1 /*#define CHASE_CHAIN*/
2 /*
3 * Copyright (c) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998
4 * The Regents of the University of California. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that: (1) source code distributions
8 * retain the above copyright notice and this paragraph in its entirety, (2)
9 * distributions including binary code include the above copyright notice and
10 * this paragraph in its entirety in the documentation or other materials
11 * provided with the distribution, and (3) all advertising materials mentioning
12 * features or use of this software display the following acknowledgement:
13 * ``This product includes software developed by the University of California,
14 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
15 * the University nor the names of its contributors may be used to endorse
16 * or promote products derived from this software without specific prior
17 * written permission.
18 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
19 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
20 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
21 */
22
23 #ifdef HAVE_CONFIG_H
24 #include <config.h>
25 #endif
26
27 #include <pcap-types.h>
28 #ifdef _WIN32
29 #include <ws2tcpip.h>
30 #else
31 #include <sys/socket.h>
32
33 #ifdef __NetBSD__
34 #include <sys/param.h>
35 #endif
36
37 #include <netinet/in.h>
38 #include <arpa/inet.h>
39 #endif /* _WIN32 */
40
41 #include <stdlib.h>
42 #include <string.h>
43 #include <memory.h>
44 #include <setjmp.h>
45 #include <stdarg.h>
46
47 #ifdef MSDOS
48 #include "pcap-dos.h"
49 #endif
50
51 #include "pcap-int.h"
52
53 #include "extract.h"
54
55 #include "ethertype.h"
56 #include "nlpid.h"
57 #include "llc.h"
58 #include "gencode.h"
59 #include "ieee80211.h"
60 #include "atmuni31.h"
61 #include "sunatmpos.h"
62 #include "ppp.h"
63 #include "pcap/sll.h"
64 #include "pcap/ipnet.h"
65 #include "arcnet.h"
66
67 #include "grammar.h"
68 #include "scanner.h"
69
70 #if defined(linux) && defined(PF_PACKET) && defined(SO_ATTACH_FILTER)
71 #include <linux/types.h>
72 #include <linux/if_packet.h>
73 #include <linux/filter.h>
74 #endif
75
76 #ifdef HAVE_NET_PFVAR_H
77 #include <sys/socket.h>
78 #include <net/if.h>
79 #include <net/pfvar.h>
80 #include <net/if_pflog.h>
81 #endif
82
83 #ifndef offsetof
84 #define offsetof(s, e) ((size_t)&((s *)0)->e)
85 #endif
86
87 #ifdef _WIN32
88 #ifdef INET6
89 #if defined(__MINGW32__) && defined(DEFINE_ADDITIONAL_IPV6_STUFF)
90 /* IPv6 address */
91 struct in6_addr
92 {
93 union
94 {
95 uint8_t u6_addr8[16];
96 uint16_t u6_addr16[8];
97 uint32_t u6_addr32[4];
98 } in6_u;
99 #define s6_addr in6_u.u6_addr8
100 #define s6_addr16 in6_u.u6_addr16
101 #define s6_addr32 in6_u.u6_addr32
102 #define s6_addr64 in6_u.u6_addr64
103 };
104
105 typedef unsigned short sa_family_t;
106
107 #define __SOCKADDR_COMMON(sa_prefix) \
108 sa_family_t sa_prefix##family
109
110 /* Ditto, for IPv6. */
111 struct sockaddr_in6
112 {
113 __SOCKADDR_COMMON (sin6_);
114 uint16_t sin6_port; /* Transport layer port # */
115 uint32_t sin6_flowinfo; /* IPv6 flow information */
116 struct in6_addr sin6_addr; /* IPv6 address */
117 };
118
119 #ifndef EAI_ADDRFAMILY
120 struct addrinfo {
121 int ai_flags; /* AI_PASSIVE, AI_CANONNAME */
122 int ai_family; /* PF_xxx */
123 int ai_socktype; /* SOCK_xxx */
124 int ai_protocol; /* 0 or IPPROTO_xxx for IPv4 and IPv6 */
125 size_t ai_addrlen; /* length of ai_addr */
126 char *ai_canonname; /* canonical name for hostname */
127 struct sockaddr *ai_addr; /* binary address */
128 struct addrinfo *ai_next; /* next structure in linked list */
129 };
130 #endif /* EAI_ADDRFAMILY */
131 #endif /* defined(__MINGW32__) && defined(DEFINE_ADDITIONAL_IPV6_STUFF) */
132 #endif /* INET6 */
133 #else /* _WIN32 */
134 #include <netdb.h> /* for "struct addrinfo" */
135 #endif /* _WIN32 */
136 #include <pcap/namedb.h>
137
138 #include "nametoaddr.h"
139
140 #define ETHERMTU 1500
141
142 #ifndef ETHERTYPE_TEB
143 #define ETHERTYPE_TEB 0x6558
144 #endif
145
146 #ifndef IPPROTO_HOPOPTS
147 #define IPPROTO_HOPOPTS 0
148 #endif
149 #ifndef IPPROTO_ROUTING
150 #define IPPROTO_ROUTING 43
151 #endif
152 #ifndef IPPROTO_FRAGMENT
153 #define IPPROTO_FRAGMENT 44
154 #endif
155 #ifndef IPPROTO_DSTOPTS
156 #define IPPROTO_DSTOPTS 60
157 #endif
158 #ifndef IPPROTO_SCTP
159 #define IPPROTO_SCTP 132
160 #endif
161
162 #define GENEVE_PORT 6081
163
164 #ifdef HAVE_OS_PROTO_H
165 #include "os-proto.h"
166 #endif
167
168 #define JMP(c) ((c)|BPF_JMP|BPF_K)
169
170 /*
171 * "Push" the current value of the link-layer header type and link-layer
172 * header offset onto a "stack", and set a new value. (It's not a
173 * full-blown stack; we keep only the top two items.)
174 */
175 #define PUSH_LINKHDR(cs, new_linktype, new_is_variable, new_constant_part, new_reg) \
176 { \
177 (cs)->prevlinktype = (cs)->linktype; \
178 (cs)->off_prevlinkhdr = (cs)->off_linkhdr; \
179 (cs)->linktype = (new_linktype); \
180 (cs)->off_linkhdr.is_variable = (new_is_variable); \
181 (cs)->off_linkhdr.constant_part = (new_constant_part); \
182 (cs)->off_linkhdr.reg = (new_reg); \
183 (cs)->is_geneve = 0; \
184 }
185
186 /*
187 * Offset "not set" value.
188 */
189 #define OFFSET_NOT_SET 0xffffffffU
190
191 /*
192 * Absolute offsets, which are offsets from the beginning of the raw
193 * packet data, are, in the general case, the sum of a variable value
194 * and a constant value; the variable value may be absent, in which
195 * case the offset is only the constant value, and the constant value
196 * may be zero, in which case the offset is only the variable value.
197 *
198 * bpf_abs_offset is a structure containing all that information:
199 *
200 * is_variable is 1 if there's a variable part.
201 *
202 * constant_part is the constant part of the value, possibly zero;
203 *
204 * if is_variable is 1, reg is the register number for a register
205 * containing the variable value if the register has been assigned,
206 * and -1 otherwise.
207 */
208 typedef struct {
209 int is_variable;
210 u_int constant_part;
211 int reg;
212 } bpf_abs_offset;
213
214 /*
215 * Value passed to gen_load_a() to indicate what the offset argument
216 * is relative to the beginning of.
217 */
218 enum e_offrel {
219 OR_PACKET, /* full packet data */
220 OR_LINKHDR, /* link-layer header */
221 OR_PREVLINKHDR, /* previous link-layer header */
222 OR_LLC, /* 802.2 LLC header */
223 OR_PREVMPLSHDR, /* previous MPLS header */
224 OR_LINKTYPE, /* link-layer type */
225 OR_LINKPL, /* link-layer payload */
226 OR_LINKPL_NOSNAP, /* link-layer payload, with no SNAP header at the link layer */
227 OR_TRAN_IPV4, /* transport-layer header, with IPv4 network layer */
228 OR_TRAN_IPV6 /* transport-layer header, with IPv6 network layer */
229 };
230
231 /*
232 * We divy out chunks of memory rather than call malloc each time so
233 * we don't have to worry about leaking memory. It's probably
234 * not a big deal if all this memory was wasted but if this ever
235 * goes into a library that would probably not be a good idea.
236 *
237 * XXX - this *is* in a library....
238 */
239 #define NCHUNKS 16
240 #define CHUNK0SIZE 1024
241 struct chunk {
242 size_t n_left;
243 void *m;
244 };
245
246 /* Code generator state */
247
248 struct _compiler_state {
249 jmp_buf top_ctx;
250 pcap_t *bpf_pcap;
251
252 struct icode ic;
253
254 int snaplen;
255
256 int linktype;
257 int prevlinktype;
258 int outermostlinktype;
259
260 bpf_u_int32 netmask;
261 int no_optimize;
262
263 /* Hack for handling VLAN and MPLS stacks. */
264 u_int label_stack_depth;
265 u_int vlan_stack_depth;
266
267 /* XXX */
268 u_int pcap_fddipad;
269
270 /*
271 * As errors are handled by a longjmp, anything allocated must
272 * be freed in the longjmp handler, so it must be reachable
273 * from that handler.
274 *
275 * One thing that's allocated is the result of pcap_nametoaddrinfo();
276 * it must be freed with freeaddrinfo(). This variable points to
277 * any addrinfo structure that would need to be freed.
278 */
279 struct addrinfo *ai;
280
281 /*
282 * Another thing that's allocated is the result of pcap_ether_aton();
283 * it must be freed with free(). This variable points to any
284 * address that would need to be freed.
285 */
286 u_char *e;
287
288 /*
289 * Various code constructs need to know the layout of the packet.
290 * These values give the necessary offsets from the beginning
291 * of the packet data.
292 */
293
294 /*
295 * Absolute offset of the beginning of the link-layer header.
296 */
297 bpf_abs_offset off_linkhdr;
298
299 /*
300 * If we're checking a link-layer header for a packet encapsulated
301 * in another protocol layer, this is the equivalent information
302 * for the previous layers' link-layer header from the beginning
303 * of the raw packet data.
304 */
305 bpf_abs_offset off_prevlinkhdr;
306
307 /*
308 * This is the equivalent information for the outermost layers'
309 * link-layer header.
310 */
311 bpf_abs_offset off_outermostlinkhdr;
312
313 /*
314 * Absolute offset of the beginning of the link-layer payload.
315 */
316 bpf_abs_offset off_linkpl;
317
318 /*
319 * "off_linktype" is the offset to information in the link-layer
320 * header giving the packet type. This is an absolute offset
321 * from the beginning of the packet.
322 *
323 * For Ethernet, it's the offset of the Ethernet type field; this
324 * means that it must have a value that skips VLAN tags.
325 *
326 * For link-layer types that always use 802.2 headers, it's the
327 * offset of the LLC header; this means that it must have a value
328 * that skips VLAN tags.
329 *
330 * For PPP, it's the offset of the PPP type field.
331 *
332 * For Cisco HDLC, it's the offset of the CHDLC type field.
333 *
334 * For BSD loopback, it's the offset of the AF_ value.
335 *
336 * For Linux cooked sockets, it's the offset of the type field.
337 *
338 * off_linktype.constant_part is set to OFFSET_NOT_SET for no
339 * encapsulation, in which case, IP is assumed.
340 */
341 bpf_abs_offset off_linktype;
342
343 /*
344 * TRUE if the link layer includes an ATM pseudo-header.
345 */
346 int is_atm;
347
348 /*
349 * TRUE if "geneve" appeared in the filter; it causes us to
350 * generate code that checks for a Geneve header and assume
351 * that later filters apply to the encapsulated payload.
352 */
353 int is_geneve;
354
355 /*
356 * TRUE if we need variable length part of VLAN offset
357 */
358 int is_vlan_vloffset;
359
360 /*
361 * These are offsets for the ATM pseudo-header.
362 */
363 u_int off_vpi;
364 u_int off_vci;
365 u_int off_proto;
366
367 /*
368 * These are offsets for the MTP2 fields.
369 */
370 u_int off_li;
371 u_int off_li_hsl;
372
373 /*
374 * These are offsets for the MTP3 fields.
375 */
376 u_int off_sio;
377 u_int off_opc;
378 u_int off_dpc;
379 u_int off_sls;
380
381 /*
382 * This is the offset of the first byte after the ATM pseudo_header,
383 * or -1 if there is no ATM pseudo-header.
384 */
385 u_int off_payload;
386
387 /*
388 * These are offsets to the beginning of the network-layer header.
389 * They are relative to the beginning of the link-layer payload
390 * (i.e., they don't include off_linkhdr.constant_part or
391 * off_linkpl.constant_part).
392 *
393 * If the link layer never uses 802.2 LLC:
394 *
395 * "off_nl" and "off_nl_nosnap" are the same.
396 *
397 * If the link layer always uses 802.2 LLC:
398 *
399 * "off_nl" is the offset if there's a SNAP header following
400 * the 802.2 header;
401 *
402 * "off_nl_nosnap" is the offset if there's no SNAP header.
403 *
404 * If the link layer is Ethernet:
405 *
406 * "off_nl" is the offset if the packet is an Ethernet II packet
407 * (we assume no 802.3+802.2+SNAP);
408 *
409 * "off_nl_nosnap" is the offset if the packet is an 802.3 packet
410 * with an 802.2 header following it.
411 */
412 u_int off_nl;
413 u_int off_nl_nosnap;
414
415 /*
416 * Here we handle simple allocation of the scratch registers.
417 * If too many registers are alloc'd, the allocator punts.
418 */
419 int regused[BPF_MEMWORDS];
420 int curreg;
421
422 /*
423 * Memory chunks.
424 */
425 struct chunk chunks[NCHUNKS];
426 int cur_chunk;
427 };
428
429 /*
430 * For use by routines outside this file.
431 */
432 /* VARARGS */
433 void
bpf_set_error(compiler_state_t * cstate,const char * fmt,...)434 bpf_set_error(compiler_state_t *cstate, const char *fmt, ...)
435 {
436 va_list ap;
437
438 va_start(ap, fmt);
439 (void)pcap_vsnprintf(cstate->bpf_pcap->errbuf, PCAP_ERRBUF_SIZE,
440 fmt, ap);
441 va_end(ap);
442 }
443
444 /*
445 * For use *ONLY* in routines in this file.
446 */
447 static void PCAP_NORETURN bpf_error(compiler_state_t *, const char *, ...)
448 PCAP_PRINTFLIKE(2, 3);
449
450 /* VARARGS */
451 static void PCAP_NORETURN
bpf_error(compiler_state_t * cstate,const char * fmt,...)452 bpf_error(compiler_state_t *cstate, const char *fmt, ...)
453 {
454 va_list ap;
455
456 va_start(ap, fmt);
457 (void)pcap_vsnprintf(cstate->bpf_pcap->errbuf, PCAP_ERRBUF_SIZE,
458 fmt, ap);
459 va_end(ap);
460 longjmp(cstate->top_ctx, 1);
461 /*NOTREACHED*/
462 }
463
464 static int init_linktype(compiler_state_t *, pcap_t *);
465
466 static void init_regs(compiler_state_t *);
467 static int alloc_reg(compiler_state_t *);
468 static void free_reg(compiler_state_t *, int);
469
470 static void initchunks(compiler_state_t *cstate);
471 static void *newchunk_nolongjmp(compiler_state_t *cstate, size_t);
472 static void *newchunk(compiler_state_t *cstate, size_t);
473 static void freechunks(compiler_state_t *cstate);
474 static inline struct block *new_block(compiler_state_t *cstate, int);
475 static inline struct slist *new_stmt(compiler_state_t *cstate, int);
476 static struct block *gen_retblk(compiler_state_t *cstate, int);
477 static inline void syntax(compiler_state_t *cstate);
478
479 static void backpatch(struct block *, struct block *);
480 static void merge(struct block *, struct block *);
481 static struct block *gen_cmp(compiler_state_t *, enum e_offrel, u_int,
482 u_int, bpf_int32);
483 static struct block *gen_cmp_gt(compiler_state_t *, enum e_offrel, u_int,
484 u_int, bpf_int32);
485 static struct block *gen_cmp_ge(compiler_state_t *, enum e_offrel, u_int,
486 u_int, bpf_int32);
487 static struct block *gen_cmp_lt(compiler_state_t *, enum e_offrel, u_int,
488 u_int, bpf_int32);
489 static struct block *gen_cmp_le(compiler_state_t *, enum e_offrel, u_int,
490 u_int, bpf_int32);
491 static struct block *gen_mcmp(compiler_state_t *, enum e_offrel, u_int,
492 u_int, bpf_int32, bpf_u_int32);
493 static struct block *gen_bcmp(compiler_state_t *, enum e_offrel, u_int,
494 u_int, const u_char *);
495 static struct block *gen_ncmp(compiler_state_t *, enum e_offrel, bpf_u_int32,
496 bpf_u_int32, bpf_u_int32, bpf_u_int32, int, bpf_int32);
497 static struct slist *gen_load_absoffsetrel(compiler_state_t *, bpf_abs_offset *,
498 u_int, u_int);
499 static struct slist *gen_load_a(compiler_state_t *, enum e_offrel, u_int,
500 u_int);
501 static struct slist *gen_loadx_iphdrlen(compiler_state_t *);
502 static struct block *gen_uncond(compiler_state_t *, int);
503 static inline struct block *gen_true(compiler_state_t *);
504 static inline struct block *gen_false(compiler_state_t *);
505 static struct block *gen_ether_linktype(compiler_state_t *, int);
506 static struct block *gen_ipnet_linktype(compiler_state_t *, int);
507 static struct block *gen_linux_sll_linktype(compiler_state_t *, int);
508 static struct slist *gen_load_prism_llprefixlen(compiler_state_t *);
509 static struct slist *gen_load_avs_llprefixlen(compiler_state_t *);
510 static struct slist *gen_load_radiotap_llprefixlen(compiler_state_t *);
511 static struct slist *gen_load_ppi_llprefixlen(compiler_state_t *);
512 static void insert_compute_vloffsets(compiler_state_t *, struct block *);
513 static struct slist *gen_abs_offset_varpart(compiler_state_t *,
514 bpf_abs_offset *);
515 static int ethertype_to_ppptype(int);
516 static struct block *gen_linktype(compiler_state_t *, int);
517 static struct block *gen_snap(compiler_state_t *, bpf_u_int32, bpf_u_int32);
518 static struct block *gen_llc_linktype(compiler_state_t *, int);
519 static struct block *gen_hostop(compiler_state_t *, bpf_u_int32, bpf_u_int32,
520 int, int, u_int, u_int);
521 #ifdef INET6
522 static struct block *gen_hostop6(compiler_state_t *, struct in6_addr *,
523 struct in6_addr *, int, int, u_int, u_int);
524 #endif
525 static struct block *gen_ahostop(compiler_state_t *, const u_char *, int);
526 static struct block *gen_ehostop(compiler_state_t *, const u_char *, int);
527 static struct block *gen_fhostop(compiler_state_t *, const u_char *, int);
528 static struct block *gen_thostop(compiler_state_t *, const u_char *, int);
529 static struct block *gen_wlanhostop(compiler_state_t *, const u_char *, int);
530 static struct block *gen_ipfchostop(compiler_state_t *, const u_char *, int);
531 static struct block *gen_dnhostop(compiler_state_t *, bpf_u_int32, int);
532 static struct block *gen_mpls_linktype(compiler_state_t *, int);
533 static struct block *gen_host(compiler_state_t *, bpf_u_int32, bpf_u_int32,
534 int, int, int);
535 #ifdef INET6
536 static struct block *gen_host6(compiler_state_t *, struct in6_addr *,
537 struct in6_addr *, int, int, int);
538 #endif
539 #ifndef INET6
540 static struct block *gen_gateway(compiler_state_t *, const u_char *,
541 struct addrinfo *, int, int);
542 #endif
543 static struct block *gen_ipfrag(compiler_state_t *);
544 static struct block *gen_portatom(compiler_state_t *, int, bpf_int32);
545 static struct block *gen_portrangeatom(compiler_state_t *, int, bpf_int32,
546 bpf_int32);
547 static struct block *gen_portatom6(compiler_state_t *, int, bpf_int32);
548 static struct block *gen_portrangeatom6(compiler_state_t *, int, bpf_int32,
549 bpf_int32);
550 struct block *gen_portop(compiler_state_t *, int, int, int);
551 static struct block *gen_port(compiler_state_t *, int, int, int);
552 struct block *gen_portrangeop(compiler_state_t *, int, int, int, int);
553 static struct block *gen_portrange(compiler_state_t *, int, int, int, int);
554 struct block *gen_portop6(compiler_state_t *, int, int, int);
555 static struct block *gen_port6(compiler_state_t *, int, int, int);
556 struct block *gen_portrangeop6(compiler_state_t *, int, int, int, int);
557 static struct block *gen_portrange6(compiler_state_t *, int, int, int, int);
558 static int lookup_proto(compiler_state_t *, const char *, int);
559 static struct block *gen_protochain(compiler_state_t *, int, int, int);
560 static struct block *gen_proto(compiler_state_t *, int, int, int);
561 static struct slist *xfer_to_x(compiler_state_t *, struct arth *);
562 static struct slist *xfer_to_a(compiler_state_t *, struct arth *);
563 static struct block *gen_mac_multicast(compiler_state_t *, int);
564 static struct block *gen_len(compiler_state_t *, int, int);
565 static struct block *gen_check_802_11_data_frame(compiler_state_t *);
566 static struct block *gen_geneve_ll_check(compiler_state_t *cstate);
567
568 static struct block *gen_ppi_dlt_check(compiler_state_t *);
569 static struct block *gen_atmfield_code_internal(compiler_state_t *, int,
570 bpf_int32, bpf_u_int32, int);
571 static struct block *gen_atmtype_llc(compiler_state_t *);
572 static struct block *gen_msg_abbrev(compiler_state_t *, int type);
573
574 static void
initchunks(compiler_state_t * cstate)575 initchunks(compiler_state_t *cstate)
576 {
577 int i;
578
579 for (i = 0; i < NCHUNKS; i++) {
580 cstate->chunks[i].n_left = 0;
581 cstate->chunks[i].m = NULL;
582 }
583 cstate->cur_chunk = 0;
584 }
585
586 static void *
newchunk_nolongjmp(compiler_state_t * cstate,size_t n)587 newchunk_nolongjmp(compiler_state_t *cstate, size_t n)
588 {
589 struct chunk *cp;
590 int k;
591 size_t size;
592
593 #ifndef __NetBSD__
594 /* XXX Round up to nearest long. */
595 n = (n + sizeof(long) - 1) & ~(sizeof(long) - 1);
596 #else
597 /* XXX Round up to structure boundary. */
598 n = ALIGN(n);
599 #endif
600
601 cp = &cstate->chunks[cstate->cur_chunk];
602 if (n > cp->n_left) {
603 ++cp;
604 k = ++cstate->cur_chunk;
605 if (k >= NCHUNKS) {
606 bpf_set_error(cstate, "out of memory");
607 return (NULL);
608 }
609 size = CHUNK0SIZE << k;
610 cp->m = (void *)malloc(size);
611 if (cp->m == NULL) {
612 bpf_set_error(cstate, "out of memory");
613 return (NULL);
614 }
615 memset((char *)cp->m, 0, size);
616 cp->n_left = size;
617 if (n > size) {
618 bpf_set_error(cstate, "out of memory");
619 return (NULL);
620 }
621 }
622 cp->n_left -= n;
623 return (void *)((char *)cp->m + cp->n_left);
624 }
625
626 static void *
newchunk(compiler_state_t * cstate,size_t n)627 newchunk(compiler_state_t *cstate, size_t n)
628 {
629 void *p;
630
631 p = newchunk_nolongjmp(cstate, n);
632 if (p == NULL) {
633 longjmp(cstate->top_ctx, 1);
634 /*NOTREACHED*/
635 }
636 return (p);
637 }
638
639 static void
freechunks(compiler_state_t * cstate)640 freechunks(compiler_state_t *cstate)
641 {
642 int i;
643
644 for (i = 0; i < NCHUNKS; ++i)
645 if (cstate->chunks[i].m != NULL)
646 free(cstate->chunks[i].m);
647 }
648
649 /*
650 * A strdup whose allocations are freed after code generation is over.
651 * This is used by the lexical analyzer, so it can't longjmp; it just
652 * returns NULL on an allocation error, and the callers must check
653 * for it.
654 */
655 char *
sdup(compiler_state_t * cstate,const char * s)656 sdup(compiler_state_t *cstate, const char *s)
657 {
658 size_t n = strlen(s) + 1;
659 char *cp = newchunk_nolongjmp(cstate, n);
660
661 if (cp == NULL)
662 return (NULL);
663 pcap_strlcpy(cp, s, n);
664 return (cp);
665 }
666
667 static inline struct block *
new_block(compiler_state_t * cstate,int code)668 new_block(compiler_state_t *cstate, int code)
669 {
670 struct block *p;
671
672 p = (struct block *)newchunk(cstate, sizeof(*p));
673 p->s.code = code;
674 p->head = p;
675
676 return p;
677 }
678
679 static inline struct slist *
new_stmt(compiler_state_t * cstate,int code)680 new_stmt(compiler_state_t *cstate, int code)
681 {
682 struct slist *p;
683
684 p = (struct slist *)newchunk(cstate, sizeof(*p));
685 p->s.code = code;
686
687 return p;
688 }
689
690 static struct block *
gen_retblk(compiler_state_t * cstate,int v)691 gen_retblk(compiler_state_t *cstate, int v)
692 {
693 struct block *b = new_block(cstate, BPF_RET|BPF_K);
694
695 b->s.k = v;
696 return b;
697 }
698
699 static inline PCAP_NORETURN_DEF void
syntax(compiler_state_t * cstate)700 syntax(compiler_state_t *cstate)
701 {
702 bpf_error(cstate, "syntax error in filter expression");
703 }
704
705 int
pcap_compile(pcap_t * p,struct bpf_program * program,const char * buf,int optimize,bpf_u_int32 mask)706 pcap_compile(pcap_t *p, struct bpf_program *program,
707 const char *buf, int optimize, bpf_u_int32 mask)
708 {
709 #ifdef _WIN32
710 static int done = 0;
711 #endif
712 compiler_state_t cstate;
713 const char * volatile xbuf = buf;
714 yyscan_t scanner = NULL;
715 volatile YY_BUFFER_STATE in_buffer = NULL;
716 u_int len;
717 int rc;
718
719 /*
720 * If this pcap_t hasn't been activated, it doesn't have a
721 * link-layer type, so we can't use it.
722 */
723 if (!p->activated) {
724 pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
725 "not-yet-activated pcap_t passed to pcap_compile");
726 return (-1);
727 }
728
729 #ifdef _WIN32
730 if (!done)
731 pcap_wsockinit();
732 done = 1;
733 #endif
734
735 #ifdef ENABLE_REMOTE
736 /*
737 * If the device on which we're capturing need to be notified
738 * that a new filter is being compiled, do so.
739 *
740 * This allows them to save a copy of it, in case, for example,
741 * they're implementing a form of remote packet capture, and
742 * want the remote machine to filter out the packets in which
743 * it's sending the packets it's captured.
744 *
745 * XXX - the fact that we happen to be compiling a filter
746 * doesn't necessarily mean we'll be installing it as the
747 * filter for this pcap_t; we might be running it from userland
748 * on captured packets to do packet classification. We really
749 * need a better way of handling this, but this is all that
750 * the WinPcap remote capture code did.
751 */
752 if (p->save_current_filter_op != NULL)
753 (p->save_current_filter_op)(p, buf);
754 #endif
755
756 initchunks(&cstate);
757 cstate.no_optimize = 0;
758 #ifdef INET6
759 cstate.ai = NULL;
760 #endif
761 cstate.e = NULL;
762 cstate.ic.root = NULL;
763 cstate.ic.cur_mark = 0;
764 cstate.bpf_pcap = p;
765 init_regs(&cstate);
766
767 cstate.netmask = mask;
768
769 cstate.snaplen = pcap_snapshot(p);
770 if (cstate.snaplen == 0) {
771 pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
772 "snaplen of 0 rejects all packets");
773 rc = -1;
774 goto quit;
775 }
776
777 if (pcap_lex_init(&scanner) != 0)
778 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
779 errno, "can't initialize scanner");
780 in_buffer = pcap__scan_string(xbuf ? xbuf : "", scanner);
781
782 /*
783 * Associate the compiler state with the lexical analyzer
784 * state.
785 */
786 pcap_set_extra(&cstate, scanner);
787
788 if (init_linktype(&cstate, p) == -1) {
789 rc = -1;
790 goto quit;
791 }
792 if (pcap_parse(scanner, &cstate) != 0) {
793 #ifdef INET6
794 if (cstate.ai != NULL)
795 freeaddrinfo(cstate.ai);
796 #endif
797 if (cstate.e != NULL)
798 free(cstate.e);
799 rc = -1;
800 goto quit;
801 }
802
803 if (cstate.ic.root == NULL) {
804 /*
805 * Catch errors reported by gen_retblk().
806 */
807 if (setjmp(cstate.top_ctx)) {
808 rc = -1;
809 goto quit;
810 }
811 cstate.ic.root = gen_retblk(&cstate, cstate.snaplen);
812 }
813
814 if (optimize && !cstate.no_optimize) {
815 if (bpf_optimize(&cstate.ic, p->errbuf) == -1) {
816 /* Failure */
817 rc = -1;
818 goto quit;
819 }
820 if (cstate.ic.root == NULL ||
821 (cstate.ic.root->s.code == (BPF_RET|BPF_K) && cstate.ic.root->s.k == 0)) {
822 (void)pcap_snprintf(p->errbuf, PCAP_ERRBUF_SIZE,
823 "expression rejects all packets");
824 rc = -1;
825 goto quit;
826 }
827 }
828 program->bf_insns = icode_to_fcode(&cstate.ic,
829 cstate.ic.root, &len, p->errbuf);
830 if (program->bf_insns == NULL) {
831 /* Failure */
832 rc = -1;
833 goto quit;
834 }
835 program->bf_len = len;
836
837 rc = 0; /* We're all okay */
838
839 quit:
840 /*
841 * Clean up everything for the lexical analyzer.
842 */
843 if (in_buffer != NULL)
844 pcap__delete_buffer(in_buffer, scanner);
845 if (scanner != NULL)
846 pcap_lex_destroy(scanner);
847
848 /*
849 * Clean up our own allocated memory.
850 */
851 freechunks(&cstate);
852
853 return (rc);
854 }
855
856 /*
857 * entry point for using the compiler with no pcap open
858 * pass in all the stuff that is needed explicitly instead.
859 */
860 int
pcap_compile_nopcap(int snaplen_arg,int linktype_arg,struct bpf_program * program,const char * buf,int optimize,bpf_u_int32 mask)861 pcap_compile_nopcap(int snaplen_arg, int linktype_arg,
862 struct bpf_program *program,
863 const char *buf, int optimize, bpf_u_int32 mask)
864 {
865 pcap_t *p;
866 int ret;
867
868 p = pcap_open_dead(linktype_arg, snaplen_arg);
869 if (p == NULL)
870 return (-1);
871 ret = pcap_compile(p, program, buf, optimize, mask);
872 pcap_close(p);
873 return (ret);
874 }
875
876 /*
877 * Clean up a "struct bpf_program" by freeing all the memory allocated
878 * in it.
879 */
880 void
pcap_freecode(struct bpf_program * program)881 pcap_freecode(struct bpf_program *program)
882 {
883 program->bf_len = 0;
884 if (program->bf_insns != NULL) {
885 free((char *)program->bf_insns);
886 program->bf_insns = NULL;
887 }
888 }
889
890 /*
891 * Backpatch the blocks in 'list' to 'target'. The 'sense' field indicates
892 * which of the jt and jf fields has been resolved and which is a pointer
893 * back to another unresolved block (or nil). At least one of the fields
894 * in each block is already resolved.
895 */
896 static void
backpatch(struct block * list,struct block * target)897 backpatch(struct block *list, struct block *target)
898 {
899 struct block *next;
900
901 while (list) {
902 if (!list->sense) {
903 next = JT(list);
904 JT(list) = target;
905 } else {
906 next = JF(list);
907 JF(list) = target;
908 }
909 list = next;
910 }
911 }
912
913 /*
914 * Merge the lists in b0 and b1, using the 'sense' field to indicate
915 * which of jt and jf is the link.
916 */
917 static void
merge(struct block * b0,struct block * b1)918 merge(struct block *b0, struct block *b1)
919 {
920 register struct block **p = &b0;
921
922 /* Find end of list. */
923 while (*p)
924 p = !((*p)->sense) ? &JT(*p) : &JF(*p);
925
926 /* Concatenate the lists. */
927 *p = b1;
928 }
929
930 int
finish_parse(compiler_state_t * cstate,struct block * p)931 finish_parse(compiler_state_t *cstate, struct block *p)
932 {
933 struct block *ppi_dlt_check;
934
935 /*
936 * Catch errors reported by us and routines below us, and return -1
937 * on an error.
938 */
939 if (setjmp(cstate->top_ctx))
940 return (-1);
941
942 /*
943 * Insert before the statements of the first (root) block any
944 * statements needed to load the lengths of any variable-length
945 * headers into registers.
946 *
947 * XXX - a fancier strategy would be to insert those before the
948 * statements of all blocks that use those lengths and that
949 * have no predecessors that use them, so that we only compute
950 * the lengths if we need them. There might be even better
951 * approaches than that.
952 *
953 * However, those strategies would be more complicated, and
954 * as we don't generate code to compute a length if the
955 * program has no tests that use the length, and as most
956 * tests will probably use those lengths, we would just
957 * postpone computing the lengths so that it's not done
958 * for tests that fail early, and it's not clear that's
959 * worth the effort.
960 */
961 insert_compute_vloffsets(cstate, p->head);
962
963 /*
964 * For DLT_PPI captures, generate a check of the per-packet
965 * DLT value to make sure it's DLT_IEEE802_11.
966 *
967 * XXX - TurboCap cards use DLT_PPI for Ethernet.
968 * Can we just define some DLT_ETHERNET_WITH_PHDR pseudo-header
969 * with appropriate Ethernet information and use that rather
970 * than using something such as DLT_PPI where you don't know
971 * the link-layer header type until runtime, which, in the
972 * general case, would force us to generate both Ethernet *and*
973 * 802.11 code (*and* anything else for which PPI is used)
974 * and choose between them early in the BPF program?
975 */
976 ppi_dlt_check = gen_ppi_dlt_check(cstate);
977 if (ppi_dlt_check != NULL)
978 gen_and(ppi_dlt_check, p);
979
980 backpatch(p, gen_retblk(cstate, cstate->snaplen));
981 p->sense = !p->sense;
982 backpatch(p, gen_retblk(cstate, 0));
983 cstate->ic.root = p->head;
984 return (0);
985 }
986
987 void
gen_and(struct block * b0,struct block * b1)988 gen_and(struct block *b0, struct block *b1)
989 {
990 backpatch(b0, b1->head);
991 b0->sense = !b0->sense;
992 b1->sense = !b1->sense;
993 merge(b1, b0);
994 b1->sense = !b1->sense;
995 b1->head = b0->head;
996 }
997
998 void
gen_or(struct block * b0,struct block * b1)999 gen_or(struct block *b0, struct block *b1)
1000 {
1001 b0->sense = !b0->sense;
1002 backpatch(b0, b1->head);
1003 b0->sense = !b0->sense;
1004 merge(b1, b0);
1005 b1->head = b0->head;
1006 }
1007
1008 void
gen_not(struct block * b)1009 gen_not(struct block *b)
1010 {
1011 b->sense = !b->sense;
1012 }
1013
1014 static struct block *
gen_cmp(compiler_state_t * cstate,enum e_offrel offrel,u_int offset,u_int size,bpf_int32 v)1015 gen_cmp(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
1016 u_int size, bpf_int32 v)
1017 {
1018 return gen_ncmp(cstate, offrel, offset, size, 0xffffffff, BPF_JEQ, 0, v);
1019 }
1020
1021 static struct block *
gen_cmp_gt(compiler_state_t * cstate,enum e_offrel offrel,u_int offset,u_int size,bpf_int32 v)1022 gen_cmp_gt(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
1023 u_int size, bpf_int32 v)
1024 {
1025 return gen_ncmp(cstate, offrel, offset, size, 0xffffffff, BPF_JGT, 0, v);
1026 }
1027
1028 static struct block *
gen_cmp_ge(compiler_state_t * cstate,enum e_offrel offrel,u_int offset,u_int size,bpf_int32 v)1029 gen_cmp_ge(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
1030 u_int size, bpf_int32 v)
1031 {
1032 return gen_ncmp(cstate, offrel, offset, size, 0xffffffff, BPF_JGE, 0, v);
1033 }
1034
1035 static struct block *
gen_cmp_lt(compiler_state_t * cstate,enum e_offrel offrel,u_int offset,u_int size,bpf_int32 v)1036 gen_cmp_lt(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
1037 u_int size, bpf_int32 v)
1038 {
1039 return gen_ncmp(cstate, offrel, offset, size, 0xffffffff, BPF_JGE, 1, v);
1040 }
1041
1042 static struct block *
gen_cmp_le(compiler_state_t * cstate,enum e_offrel offrel,u_int offset,u_int size,bpf_int32 v)1043 gen_cmp_le(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
1044 u_int size, bpf_int32 v)
1045 {
1046 return gen_ncmp(cstate, offrel, offset, size, 0xffffffff, BPF_JGT, 1, v);
1047 }
1048
1049 static struct block *
gen_mcmp(compiler_state_t * cstate,enum e_offrel offrel,u_int offset,u_int size,bpf_int32 v,bpf_u_int32 mask)1050 gen_mcmp(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
1051 u_int size, bpf_int32 v, bpf_u_int32 mask)
1052 {
1053 return gen_ncmp(cstate, offrel, offset, size, mask, BPF_JEQ, 0, v);
1054 }
1055
1056 static struct block *
gen_bcmp(compiler_state_t * cstate,enum e_offrel offrel,u_int offset,u_int size,const u_char * v)1057 gen_bcmp(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
1058 u_int size, const u_char *v)
1059 {
1060 register struct block *b, *tmp;
1061
1062 /*
1063 * XXX - the actual *instructions* do unsigned comparisons on
1064 * most platforms, and the load instructions don't do sign
1065 * extension, so gen_cmp() should really take an unsigned
1066 * value argument.
1067 *
1068 * As the load instructons also don't do sign-extension, we
1069 * fetch the values from the byte array as unsigned. We don't
1070 * want to use the signed versions of the extract calls.
1071 */
1072 b = NULL;
1073 while (size >= 4) {
1074 register const u_char *p = &v[size - 4];
1075
1076 tmp = gen_cmp(cstate, offrel, offset + size - 4, BPF_W,
1077 (bpf_int32)EXTRACT_32BITS(p));
1078 if (b != NULL)
1079 gen_and(b, tmp);
1080 b = tmp;
1081 size -= 4;
1082 }
1083 while (size >= 2) {
1084 register const u_char *p = &v[size - 2];
1085
1086 tmp = gen_cmp(cstate, offrel, offset + size - 2, BPF_H,
1087 (bpf_int32)EXTRACT_16BITS(p));
1088 if (b != NULL)
1089 gen_and(b, tmp);
1090 b = tmp;
1091 size -= 2;
1092 }
1093 if (size > 0) {
1094 tmp = gen_cmp(cstate, offrel, offset, BPF_B, (bpf_int32)v[0]);
1095 if (b != NULL)
1096 gen_and(b, tmp);
1097 b = tmp;
1098 }
1099 return b;
1100 }
1101
1102 /*
1103 * AND the field of size "size" at offset "offset" relative to the header
1104 * specified by "offrel" with "mask", and compare it with the value "v"
1105 * with the test specified by "jtype"; if "reverse" is true, the test
1106 * should test the opposite of "jtype".
1107 */
1108 static struct block *
gen_ncmp(compiler_state_t * cstate,enum e_offrel offrel,bpf_u_int32 offset,bpf_u_int32 size,bpf_u_int32 mask,bpf_u_int32 jtype,int reverse,bpf_int32 v)1109 gen_ncmp(compiler_state_t *cstate, enum e_offrel offrel, bpf_u_int32 offset,
1110 bpf_u_int32 size, bpf_u_int32 mask, bpf_u_int32 jtype, int reverse,
1111 bpf_int32 v)
1112 {
1113 struct slist *s, *s2;
1114 struct block *b;
1115
1116 s = gen_load_a(cstate, offrel, offset, size);
1117
1118 if (mask != 0xffffffff) {
1119 s2 = new_stmt(cstate, BPF_ALU|BPF_AND|BPF_K);
1120 s2->s.k = mask;
1121 sappend(s, s2);
1122 }
1123
1124 b = new_block(cstate, JMP(jtype));
1125 b->stmts = s;
1126 b->s.k = v;
1127 if (reverse && (jtype == BPF_JGT || jtype == BPF_JGE))
1128 gen_not(b);
1129 return b;
1130 }
1131
1132 static int
init_linktype(compiler_state_t * cstate,pcap_t * p)1133 init_linktype(compiler_state_t *cstate, pcap_t *p)
1134 {
1135 cstate->pcap_fddipad = p->fddipad;
1136
1137 /*
1138 * We start out with only one link-layer header.
1139 */
1140 cstate->outermostlinktype = pcap_datalink(p);
1141 cstate->off_outermostlinkhdr.constant_part = 0;
1142 cstate->off_outermostlinkhdr.is_variable = 0;
1143 cstate->off_outermostlinkhdr.reg = -1;
1144
1145 cstate->prevlinktype = cstate->outermostlinktype;
1146 cstate->off_prevlinkhdr.constant_part = 0;
1147 cstate->off_prevlinkhdr.is_variable = 0;
1148 cstate->off_prevlinkhdr.reg = -1;
1149
1150 cstate->linktype = cstate->outermostlinktype;
1151 cstate->off_linkhdr.constant_part = 0;
1152 cstate->off_linkhdr.is_variable = 0;
1153 cstate->off_linkhdr.reg = -1;
1154
1155 /*
1156 * XXX
1157 */
1158 cstate->off_linkpl.constant_part = 0;
1159 cstate->off_linkpl.is_variable = 0;
1160 cstate->off_linkpl.reg = -1;
1161
1162 cstate->off_linktype.constant_part = 0;
1163 cstate->off_linktype.is_variable = 0;
1164 cstate->off_linktype.reg = -1;
1165
1166 /*
1167 * Assume it's not raw ATM with a pseudo-header, for now.
1168 */
1169 cstate->is_atm = 0;
1170 cstate->off_vpi = OFFSET_NOT_SET;
1171 cstate->off_vci = OFFSET_NOT_SET;
1172 cstate->off_proto = OFFSET_NOT_SET;
1173 cstate->off_payload = OFFSET_NOT_SET;
1174
1175 /*
1176 * And not Geneve.
1177 */
1178 cstate->is_geneve = 0;
1179
1180 /*
1181 * No variable length VLAN offset by default
1182 */
1183 cstate->is_vlan_vloffset = 0;
1184
1185 /*
1186 * And assume we're not doing SS7.
1187 */
1188 cstate->off_li = OFFSET_NOT_SET;
1189 cstate->off_li_hsl = OFFSET_NOT_SET;
1190 cstate->off_sio = OFFSET_NOT_SET;
1191 cstate->off_opc = OFFSET_NOT_SET;
1192 cstate->off_dpc = OFFSET_NOT_SET;
1193 cstate->off_sls = OFFSET_NOT_SET;
1194
1195 cstate->label_stack_depth = 0;
1196 cstate->vlan_stack_depth = 0;
1197
1198 switch (cstate->linktype) {
1199
1200 case DLT_ARCNET:
1201 cstate->off_linktype.constant_part = 2;
1202 cstate->off_linkpl.constant_part = 6;
1203 cstate->off_nl = 0; /* XXX in reality, variable! */
1204 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1205 break;
1206
1207 case DLT_ARCNET_LINUX:
1208 cstate->off_linktype.constant_part = 4;
1209 cstate->off_linkpl.constant_part = 8;
1210 cstate->off_nl = 0; /* XXX in reality, variable! */
1211 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1212 break;
1213
1214 case DLT_EN10MB:
1215 cstate->off_linktype.constant_part = 12;
1216 cstate->off_linkpl.constant_part = 14; /* Ethernet header length */
1217 cstate->off_nl = 0; /* Ethernet II */
1218 cstate->off_nl_nosnap = 3; /* 802.3+802.2 */
1219 break;
1220
1221 case DLT_SLIP:
1222 /*
1223 * SLIP doesn't have a link level type. The 16 byte
1224 * header is hacked into our SLIP driver.
1225 */
1226 cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1227 cstate->off_linkpl.constant_part = 16;
1228 cstate->off_nl = 0;
1229 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1230 break;
1231
1232 case DLT_SLIP_BSDOS:
1233 /* XXX this may be the same as the DLT_PPP_BSDOS case */
1234 cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1235 /* XXX end */
1236 cstate->off_linkpl.constant_part = 24;
1237 cstate->off_nl = 0;
1238 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1239 break;
1240
1241 case DLT_NULL:
1242 case DLT_LOOP:
1243 cstate->off_linktype.constant_part = 0;
1244 cstate->off_linkpl.constant_part = 4;
1245 cstate->off_nl = 0;
1246 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1247 break;
1248
1249 case DLT_ENC:
1250 cstate->off_linktype.constant_part = 0;
1251 cstate->off_linkpl.constant_part = 12;
1252 cstate->off_nl = 0;
1253 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1254 break;
1255
1256 case DLT_PPP:
1257 case DLT_PPP_PPPD:
1258 case DLT_C_HDLC: /* BSD/OS Cisco HDLC */
1259 case DLT_PPP_SERIAL: /* NetBSD sync/async serial PPP */
1260 cstate->off_linktype.constant_part = 2; /* skip HDLC-like framing */
1261 cstate->off_linkpl.constant_part = 4; /* skip HDLC-like framing and protocol field */
1262 cstate->off_nl = 0;
1263 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1264 break;
1265
1266 case DLT_PPP_ETHER:
1267 /*
1268 * This does no include the Ethernet header, and
1269 * only covers session state.
1270 */
1271 cstate->off_linktype.constant_part = 6;
1272 cstate->off_linkpl.constant_part = 8;
1273 cstate->off_nl = 0;
1274 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1275 break;
1276
1277 case DLT_PPP_BSDOS:
1278 cstate->off_linktype.constant_part = 5;
1279 cstate->off_linkpl.constant_part = 24;
1280 cstate->off_nl = 0;
1281 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1282 break;
1283
1284 case DLT_FDDI:
1285 /*
1286 * FDDI doesn't really have a link-level type field.
1287 * We set "off_linktype" to the offset of the LLC header.
1288 *
1289 * To check for Ethernet types, we assume that SSAP = SNAP
1290 * is being used and pick out the encapsulated Ethernet type.
1291 * XXX - should we generate code to check for SNAP?
1292 */
1293 cstate->off_linktype.constant_part = 13;
1294 cstate->off_linktype.constant_part += cstate->pcap_fddipad;
1295 cstate->off_linkpl.constant_part = 13; /* FDDI MAC header length */
1296 cstate->off_linkpl.constant_part += cstate->pcap_fddipad;
1297 cstate->off_nl = 8; /* 802.2+SNAP */
1298 cstate->off_nl_nosnap = 3; /* 802.2 */
1299 break;
1300
1301 case DLT_IEEE802:
1302 /*
1303 * Token Ring doesn't really have a link-level type field.
1304 * We set "off_linktype" to the offset of the LLC header.
1305 *
1306 * To check for Ethernet types, we assume that SSAP = SNAP
1307 * is being used and pick out the encapsulated Ethernet type.
1308 * XXX - should we generate code to check for SNAP?
1309 *
1310 * XXX - the header is actually variable-length.
1311 * Some various Linux patched versions gave 38
1312 * as "off_linktype" and 40 as "off_nl"; however,
1313 * if a token ring packet has *no* routing
1314 * information, i.e. is not source-routed, the correct
1315 * values are 20 and 22, as they are in the vanilla code.
1316 *
1317 * A packet is source-routed iff the uppermost bit
1318 * of the first byte of the source address, at an
1319 * offset of 8, has the uppermost bit set. If the
1320 * packet is source-routed, the total number of bytes
1321 * of routing information is 2 plus bits 0x1F00 of
1322 * the 16-bit value at an offset of 14 (shifted right
1323 * 8 - figure out which byte that is).
1324 */
1325 cstate->off_linktype.constant_part = 14;
1326 cstate->off_linkpl.constant_part = 14; /* Token Ring MAC header length */
1327 cstate->off_nl = 8; /* 802.2+SNAP */
1328 cstate->off_nl_nosnap = 3; /* 802.2 */
1329 break;
1330
1331 case DLT_PRISM_HEADER:
1332 case DLT_IEEE802_11_RADIO_AVS:
1333 case DLT_IEEE802_11_RADIO:
1334 cstate->off_linkhdr.is_variable = 1;
1335 /* Fall through, 802.11 doesn't have a variable link
1336 * prefix but is otherwise the same. */
1337 /* FALLTHROUGH */
1338
1339 case DLT_IEEE802_11:
1340 /*
1341 * 802.11 doesn't really have a link-level type field.
1342 * We set "off_linktype.constant_part" to the offset of
1343 * the LLC header.
1344 *
1345 * To check for Ethernet types, we assume that SSAP = SNAP
1346 * is being used and pick out the encapsulated Ethernet type.
1347 * XXX - should we generate code to check for SNAP?
1348 *
1349 * We also handle variable-length radio headers here.
1350 * The Prism header is in theory variable-length, but in
1351 * practice it's always 144 bytes long. However, some
1352 * drivers on Linux use ARPHRD_IEEE80211_PRISM, but
1353 * sometimes or always supply an AVS header, so we
1354 * have to check whether the radio header is a Prism
1355 * header or an AVS header, so, in practice, it's
1356 * variable-length.
1357 */
1358 cstate->off_linktype.constant_part = 24;
1359 cstate->off_linkpl.constant_part = 0; /* link-layer header is variable-length */
1360 cstate->off_linkpl.is_variable = 1;
1361 cstate->off_nl = 8; /* 802.2+SNAP */
1362 cstate->off_nl_nosnap = 3; /* 802.2 */
1363 break;
1364
1365 case DLT_PPI:
1366 /*
1367 * At the moment we treat PPI the same way that we treat
1368 * normal Radiotap encoded packets. The difference is in
1369 * the function that generates the code at the beginning
1370 * to compute the header length. Since this code generator
1371 * of PPI supports bare 802.11 encapsulation only (i.e.
1372 * the encapsulated DLT should be DLT_IEEE802_11) we
1373 * generate code to check for this too.
1374 */
1375 cstate->off_linktype.constant_part = 24;
1376 cstate->off_linkpl.constant_part = 0; /* link-layer header is variable-length */
1377 cstate->off_linkpl.is_variable = 1;
1378 cstate->off_linkhdr.is_variable = 1;
1379 cstate->off_nl = 8; /* 802.2+SNAP */
1380 cstate->off_nl_nosnap = 3; /* 802.2 */
1381 break;
1382
1383 case DLT_ATM_RFC1483:
1384 case DLT_ATM_CLIP: /* Linux ATM defines this */
1385 /*
1386 * assume routed, non-ISO PDUs
1387 * (i.e., LLC = 0xAA-AA-03, OUT = 0x00-00-00)
1388 *
1389 * XXX - what about ISO PDUs, e.g. CLNP, ISIS, ESIS,
1390 * or PPP with the PPP NLPID (e.g., PPPoA)? The
1391 * latter would presumably be treated the way PPPoE
1392 * should be, so you can do "pppoe and udp port 2049"
1393 * or "pppoa and tcp port 80" and have it check for
1394 * PPPo{A,E} and a PPP protocol of IP and....
1395 */
1396 cstate->off_linktype.constant_part = 0;
1397 cstate->off_linkpl.constant_part = 0; /* packet begins with LLC header */
1398 cstate->off_nl = 8; /* 802.2+SNAP */
1399 cstate->off_nl_nosnap = 3; /* 802.2 */
1400 break;
1401
1402 case DLT_SUNATM:
1403 /*
1404 * Full Frontal ATM; you get AALn PDUs with an ATM
1405 * pseudo-header.
1406 */
1407 cstate->is_atm = 1;
1408 cstate->off_vpi = SUNATM_VPI_POS;
1409 cstate->off_vci = SUNATM_VCI_POS;
1410 cstate->off_proto = PROTO_POS;
1411 cstate->off_payload = SUNATM_PKT_BEGIN_POS;
1412 cstate->off_linktype.constant_part = cstate->off_payload;
1413 cstate->off_linkpl.constant_part = cstate->off_payload; /* if LLC-encapsulated */
1414 cstate->off_nl = 8; /* 802.2+SNAP */
1415 cstate->off_nl_nosnap = 3; /* 802.2 */
1416 break;
1417
1418 case DLT_RAW:
1419 case DLT_IPV4:
1420 case DLT_IPV6:
1421 cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1422 cstate->off_linkpl.constant_part = 0;
1423 cstate->off_nl = 0;
1424 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1425 break;
1426
1427 case DLT_LINUX_SLL: /* fake header for Linux cooked socket v1 */
1428 cstate->off_linktype.constant_part = 14;
1429 cstate->off_linkpl.constant_part = 16;
1430 cstate->off_nl = 0;
1431 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1432 break;
1433
1434 case DLT_LINUX_SLL2: /* fake header for Linux cooked socket v2 */
1435 cstate->off_linktype.constant_part = 0;
1436 cstate->off_linkpl.constant_part = 20;
1437 cstate->off_nl = 0;
1438 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1439 break;
1440
1441 case DLT_LTALK:
1442 /*
1443 * LocalTalk does have a 1-byte type field in the LLAP header,
1444 * but really it just indicates whether there is a "short" or
1445 * "long" DDP packet following.
1446 */
1447 cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1448 cstate->off_linkpl.constant_part = 0;
1449 cstate->off_nl = 0;
1450 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1451 break;
1452
1453 case DLT_IP_OVER_FC:
1454 /*
1455 * RFC 2625 IP-over-Fibre-Channel doesn't really have a
1456 * link-level type field. We set "off_linktype" to the
1457 * offset of the LLC header.
1458 *
1459 * To check for Ethernet types, we assume that SSAP = SNAP
1460 * is being used and pick out the encapsulated Ethernet type.
1461 * XXX - should we generate code to check for SNAP? RFC
1462 * 2625 says SNAP should be used.
1463 */
1464 cstate->off_linktype.constant_part = 16;
1465 cstate->off_linkpl.constant_part = 16;
1466 cstate->off_nl = 8; /* 802.2+SNAP */
1467 cstate->off_nl_nosnap = 3; /* 802.2 */
1468 break;
1469
1470 case DLT_FRELAY:
1471 /*
1472 * XXX - we should set this to handle SNAP-encapsulated
1473 * frames (NLPID of 0x80).
1474 */
1475 cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1476 cstate->off_linkpl.constant_part = 0;
1477 cstate->off_nl = 0;
1478 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1479 break;
1480
1481 /*
1482 * the only BPF-interesting FRF.16 frames are non-control frames;
1483 * Frame Relay has a variable length link-layer
1484 * so lets start with offset 4 for now and increments later on (FIXME);
1485 */
1486 case DLT_MFR:
1487 cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1488 cstate->off_linkpl.constant_part = 0;
1489 cstate->off_nl = 4;
1490 cstate->off_nl_nosnap = 0; /* XXX - for now -> no 802.2 LLC */
1491 break;
1492
1493 case DLT_APPLE_IP_OVER_IEEE1394:
1494 cstate->off_linktype.constant_part = 16;
1495 cstate->off_linkpl.constant_part = 18;
1496 cstate->off_nl = 0;
1497 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1498 break;
1499
1500 case DLT_SYMANTEC_FIREWALL:
1501 cstate->off_linktype.constant_part = 6;
1502 cstate->off_linkpl.constant_part = 44;
1503 cstate->off_nl = 0; /* Ethernet II */
1504 cstate->off_nl_nosnap = 0; /* XXX - what does it do with 802.3 packets? */
1505 break;
1506
1507 #ifdef HAVE_NET_PFVAR_H
1508 case DLT_PFLOG:
1509 cstate->off_linktype.constant_part = 0;
1510 cstate->off_linkpl.constant_part = PFLOG_HDRLEN;
1511 cstate->off_nl = 0;
1512 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
1513 break;
1514 #endif
1515
1516 case DLT_JUNIPER_MFR:
1517 case DLT_JUNIPER_MLFR:
1518 case DLT_JUNIPER_MLPPP:
1519 case DLT_JUNIPER_PPP:
1520 case DLT_JUNIPER_CHDLC:
1521 case DLT_JUNIPER_FRELAY:
1522 cstate->off_linktype.constant_part = 4;
1523 cstate->off_linkpl.constant_part = 4;
1524 cstate->off_nl = 0;
1525 cstate->off_nl_nosnap = OFFSET_NOT_SET; /* no 802.2 LLC */
1526 break;
1527
1528 case DLT_JUNIPER_ATM1:
1529 cstate->off_linktype.constant_part = 4; /* in reality variable between 4-8 */
1530 cstate->off_linkpl.constant_part = 4; /* in reality variable between 4-8 */
1531 cstate->off_nl = 0;
1532 cstate->off_nl_nosnap = 10;
1533 break;
1534
1535 case DLT_JUNIPER_ATM2:
1536 cstate->off_linktype.constant_part = 8; /* in reality variable between 8-12 */
1537 cstate->off_linkpl.constant_part = 8; /* in reality variable between 8-12 */
1538 cstate->off_nl = 0;
1539 cstate->off_nl_nosnap = 10;
1540 break;
1541
1542 /* frames captured on a Juniper PPPoE service PIC
1543 * contain raw ethernet frames */
1544 case DLT_JUNIPER_PPPOE:
1545 case DLT_JUNIPER_ETHER:
1546 cstate->off_linkpl.constant_part = 14;
1547 cstate->off_linktype.constant_part = 16;
1548 cstate->off_nl = 18; /* Ethernet II */
1549 cstate->off_nl_nosnap = 21; /* 802.3+802.2 */
1550 break;
1551
1552 case DLT_JUNIPER_PPPOE_ATM:
1553 cstate->off_linktype.constant_part = 4;
1554 cstate->off_linkpl.constant_part = 6;
1555 cstate->off_nl = 0;
1556 cstate->off_nl_nosnap = OFFSET_NOT_SET; /* no 802.2 LLC */
1557 break;
1558
1559 case DLT_JUNIPER_GGSN:
1560 cstate->off_linktype.constant_part = 6;
1561 cstate->off_linkpl.constant_part = 12;
1562 cstate->off_nl = 0;
1563 cstate->off_nl_nosnap = OFFSET_NOT_SET; /* no 802.2 LLC */
1564 break;
1565
1566 case DLT_JUNIPER_ES:
1567 cstate->off_linktype.constant_part = 6;
1568 cstate->off_linkpl.constant_part = OFFSET_NOT_SET; /* not really a network layer but raw IP addresses */
1569 cstate->off_nl = OFFSET_NOT_SET; /* not really a network layer but raw IP addresses */
1570 cstate->off_nl_nosnap = OFFSET_NOT_SET; /* no 802.2 LLC */
1571 break;
1572
1573 case DLT_JUNIPER_MONITOR:
1574 cstate->off_linktype.constant_part = 12;
1575 cstate->off_linkpl.constant_part = 12;
1576 cstate->off_nl = 0; /* raw IP/IP6 header */
1577 cstate->off_nl_nosnap = OFFSET_NOT_SET; /* no 802.2 LLC */
1578 break;
1579
1580 case DLT_BACNET_MS_TP:
1581 cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1582 cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1583 cstate->off_nl = OFFSET_NOT_SET;
1584 cstate->off_nl_nosnap = OFFSET_NOT_SET;
1585 break;
1586
1587 case DLT_JUNIPER_SERVICES:
1588 cstate->off_linktype.constant_part = 12;
1589 cstate->off_linkpl.constant_part = OFFSET_NOT_SET; /* L3 proto location dep. on cookie type */
1590 cstate->off_nl = OFFSET_NOT_SET; /* L3 proto location dep. on cookie type */
1591 cstate->off_nl_nosnap = OFFSET_NOT_SET; /* no 802.2 LLC */
1592 break;
1593
1594 case DLT_JUNIPER_VP:
1595 cstate->off_linktype.constant_part = 18;
1596 cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1597 cstate->off_nl = OFFSET_NOT_SET;
1598 cstate->off_nl_nosnap = OFFSET_NOT_SET;
1599 break;
1600
1601 case DLT_JUNIPER_ST:
1602 cstate->off_linktype.constant_part = 18;
1603 cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1604 cstate->off_nl = OFFSET_NOT_SET;
1605 cstate->off_nl_nosnap = OFFSET_NOT_SET;
1606 break;
1607
1608 case DLT_JUNIPER_ISM:
1609 cstate->off_linktype.constant_part = 8;
1610 cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1611 cstate->off_nl = OFFSET_NOT_SET;
1612 cstate->off_nl_nosnap = OFFSET_NOT_SET;
1613 break;
1614
1615 case DLT_JUNIPER_VS:
1616 case DLT_JUNIPER_SRX_E2E:
1617 case DLT_JUNIPER_FIBRECHANNEL:
1618 case DLT_JUNIPER_ATM_CEMIC:
1619 cstate->off_linktype.constant_part = 8;
1620 cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1621 cstate->off_nl = OFFSET_NOT_SET;
1622 cstate->off_nl_nosnap = OFFSET_NOT_SET;
1623 break;
1624
1625 case DLT_MTP2:
1626 cstate->off_li = 2;
1627 cstate->off_li_hsl = 4;
1628 cstate->off_sio = 3;
1629 cstate->off_opc = 4;
1630 cstate->off_dpc = 4;
1631 cstate->off_sls = 7;
1632 cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1633 cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1634 cstate->off_nl = OFFSET_NOT_SET;
1635 cstate->off_nl_nosnap = OFFSET_NOT_SET;
1636 break;
1637
1638 case DLT_MTP2_WITH_PHDR:
1639 cstate->off_li = 6;
1640 cstate->off_li_hsl = 8;
1641 cstate->off_sio = 7;
1642 cstate->off_opc = 8;
1643 cstate->off_dpc = 8;
1644 cstate->off_sls = 11;
1645 cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1646 cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1647 cstate->off_nl = OFFSET_NOT_SET;
1648 cstate->off_nl_nosnap = OFFSET_NOT_SET;
1649 break;
1650
1651 case DLT_ERF:
1652 cstate->off_li = 22;
1653 cstate->off_li_hsl = 24;
1654 cstate->off_sio = 23;
1655 cstate->off_opc = 24;
1656 cstate->off_dpc = 24;
1657 cstate->off_sls = 27;
1658 cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1659 cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1660 cstate->off_nl = OFFSET_NOT_SET;
1661 cstate->off_nl_nosnap = OFFSET_NOT_SET;
1662 break;
1663
1664 case DLT_PFSYNC:
1665 cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1666 cstate->off_linkpl.constant_part = 4;
1667 cstate->off_nl = 0;
1668 cstate->off_nl_nosnap = 0;
1669 break;
1670
1671 case DLT_AX25_KISS:
1672 /*
1673 * Currently, only raw "link[N:M]" filtering is supported.
1674 */
1675 cstate->off_linktype.constant_part = OFFSET_NOT_SET; /* variable, min 15, max 71 steps of 7 */
1676 cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1677 cstate->off_nl = OFFSET_NOT_SET; /* variable, min 16, max 71 steps of 7 */
1678 cstate->off_nl_nosnap = OFFSET_NOT_SET; /* no 802.2 LLC */
1679 break;
1680
1681 case DLT_IPNET:
1682 cstate->off_linktype.constant_part = 1;
1683 cstate->off_linkpl.constant_part = 24; /* ipnet header length */
1684 cstate->off_nl = 0;
1685 cstate->off_nl_nosnap = OFFSET_NOT_SET;
1686 break;
1687
1688 case DLT_NETANALYZER:
1689 cstate->off_linkhdr.constant_part = 4; /* Ethernet header is past 4-byte pseudo-header */
1690 cstate->off_linktype.constant_part = cstate->off_linkhdr.constant_part + 12;
1691 cstate->off_linkpl.constant_part = cstate->off_linkhdr.constant_part + 14; /* pseudo-header+Ethernet header length */
1692 cstate->off_nl = 0; /* Ethernet II */
1693 cstate->off_nl_nosnap = 3; /* 802.3+802.2 */
1694 break;
1695
1696 case DLT_NETANALYZER_TRANSPARENT:
1697 cstate->off_linkhdr.constant_part = 12; /* MAC header is past 4-byte pseudo-header, preamble, and SFD */
1698 cstate->off_linktype.constant_part = cstate->off_linkhdr.constant_part + 12;
1699 cstate->off_linkpl.constant_part = cstate->off_linkhdr.constant_part + 14; /* pseudo-header+preamble+SFD+Ethernet header length */
1700 cstate->off_nl = 0; /* Ethernet II */
1701 cstate->off_nl_nosnap = 3; /* 802.3+802.2 */
1702 break;
1703
1704 default:
1705 /*
1706 * For values in the range in which we've assigned new
1707 * DLT_ values, only raw "link[N:M]" filtering is supported.
1708 */
1709 if (cstate->linktype >= DLT_MATCHING_MIN &&
1710 cstate->linktype <= DLT_MATCHING_MAX) {
1711 cstate->off_linktype.constant_part = OFFSET_NOT_SET;
1712 cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
1713 cstate->off_nl = OFFSET_NOT_SET;
1714 cstate->off_nl_nosnap = OFFSET_NOT_SET;
1715 } else {
1716 bpf_set_error(cstate, "unknown data link type %d", cstate->linktype);
1717 return (-1);
1718 }
1719 break;
1720 }
1721
1722 cstate->off_outermostlinkhdr = cstate->off_prevlinkhdr = cstate->off_linkhdr;
1723 return (0);
1724 }
1725
1726 /*
1727 * Load a value relative to the specified absolute offset.
1728 */
1729 static struct slist *
gen_load_absoffsetrel(compiler_state_t * cstate,bpf_abs_offset * abs_offset,u_int offset,u_int size)1730 gen_load_absoffsetrel(compiler_state_t *cstate, bpf_abs_offset *abs_offset,
1731 u_int offset, u_int size)
1732 {
1733 struct slist *s, *s2;
1734
1735 s = gen_abs_offset_varpart(cstate, abs_offset);
1736
1737 /*
1738 * If "s" is non-null, it has code to arrange that the X register
1739 * contains the variable part of the absolute offset, so we
1740 * generate a load relative to that, with an offset of
1741 * abs_offset->constant_part + offset.
1742 *
1743 * Otherwise, we can do an absolute load with an offset of
1744 * abs_offset->constant_part + offset.
1745 */
1746 if (s != NULL) {
1747 /*
1748 * "s" points to a list of statements that puts the
1749 * variable part of the absolute offset into the X register.
1750 * Do an indirect load, to use the X register as an offset.
1751 */
1752 s2 = new_stmt(cstate, BPF_LD|BPF_IND|size);
1753 s2->s.k = abs_offset->constant_part + offset;
1754 sappend(s, s2);
1755 } else {
1756 /*
1757 * There is no variable part of the absolute offset, so
1758 * just do an absolute load.
1759 */
1760 s = new_stmt(cstate, BPF_LD|BPF_ABS|size);
1761 s->s.k = abs_offset->constant_part + offset;
1762 }
1763 return s;
1764 }
1765
1766 /*
1767 * Load a value relative to the beginning of the specified header.
1768 */
1769 static struct slist *
gen_load_a(compiler_state_t * cstate,enum e_offrel offrel,u_int offset,u_int size)1770 gen_load_a(compiler_state_t *cstate, enum e_offrel offrel, u_int offset,
1771 u_int size)
1772 {
1773 struct slist *s, *s2;
1774
1775 /*
1776 * Squelch warnings from compilers that *don't* assume that
1777 * offrel always has a valid enum value and therefore don't
1778 * assume that we'll always go through one of the case arms.
1779 *
1780 * If we have a default case, compilers that *do* assume that
1781 * will then complain about the default case code being
1782 * unreachable.
1783 *
1784 * Damned if you do, damned if you don't.
1785 */
1786 s = NULL;
1787
1788 switch (offrel) {
1789
1790 case OR_PACKET:
1791 s = new_stmt(cstate, BPF_LD|BPF_ABS|size);
1792 s->s.k = offset;
1793 break;
1794
1795 case OR_LINKHDR:
1796 s = gen_load_absoffsetrel(cstate, &cstate->off_linkhdr, offset, size);
1797 break;
1798
1799 case OR_PREVLINKHDR:
1800 s = gen_load_absoffsetrel(cstate, &cstate->off_prevlinkhdr, offset, size);
1801 break;
1802
1803 case OR_LLC:
1804 s = gen_load_absoffsetrel(cstate, &cstate->off_linkpl, offset, size);
1805 break;
1806
1807 case OR_PREVMPLSHDR:
1808 s = gen_load_absoffsetrel(cstate, &cstate->off_linkpl, cstate->off_nl - 4 + offset, size);
1809 break;
1810
1811 case OR_LINKPL:
1812 s = gen_load_absoffsetrel(cstate, &cstate->off_linkpl, cstate->off_nl + offset, size);
1813 break;
1814
1815 case OR_LINKPL_NOSNAP:
1816 s = gen_load_absoffsetrel(cstate, &cstate->off_linkpl, cstate->off_nl_nosnap + offset, size);
1817 break;
1818
1819 case OR_LINKTYPE:
1820 s = gen_load_absoffsetrel(cstate, &cstate->off_linktype, offset, size);
1821 break;
1822
1823 case OR_TRAN_IPV4:
1824 /*
1825 * Load the X register with the length of the IPv4 header
1826 * (plus the offset of the link-layer header, if it's
1827 * preceded by a variable-length header such as a radio
1828 * header), in bytes.
1829 */
1830 s = gen_loadx_iphdrlen(cstate);
1831
1832 /*
1833 * Load the item at {offset of the link-layer payload} +
1834 * {offset, relative to the start of the link-layer
1835 * paylod, of the IPv4 header} + {length of the IPv4 header} +
1836 * {specified offset}.
1837 *
1838 * If the offset of the link-layer payload is variable,
1839 * the variable part of that offset is included in the
1840 * value in the X register, and we include the constant
1841 * part in the offset of the load.
1842 */
1843 s2 = new_stmt(cstate, BPF_LD|BPF_IND|size);
1844 s2->s.k = cstate->off_linkpl.constant_part + cstate->off_nl + offset;
1845 sappend(s, s2);
1846 break;
1847
1848 case OR_TRAN_IPV6:
1849 s = gen_load_absoffsetrel(cstate, &cstate->off_linkpl, cstate->off_nl + 40 + offset, size);
1850 break;
1851 }
1852 return s;
1853 }
1854
1855 /*
1856 * Generate code to load into the X register the sum of the length of
1857 * the IPv4 header and the variable part of the offset of the link-layer
1858 * payload.
1859 */
1860 static struct slist *
gen_loadx_iphdrlen(compiler_state_t * cstate)1861 gen_loadx_iphdrlen(compiler_state_t *cstate)
1862 {
1863 struct slist *s, *s2;
1864
1865 s = gen_abs_offset_varpart(cstate, &cstate->off_linkpl);
1866 if (s != NULL) {
1867 /*
1868 * The offset of the link-layer payload has a variable
1869 * part. "s" points to a list of statements that put
1870 * the variable part of that offset into the X register.
1871 *
1872 * The 4*([k]&0xf) addressing mode can't be used, as we
1873 * don't have a constant offset, so we have to load the
1874 * value in question into the A register and add to it
1875 * the value from the X register.
1876 */
1877 s2 = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B);
1878 s2->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
1879 sappend(s, s2);
1880 s2 = new_stmt(cstate, BPF_ALU|BPF_AND|BPF_K);
1881 s2->s.k = 0xf;
1882 sappend(s, s2);
1883 s2 = new_stmt(cstate, BPF_ALU|BPF_LSH|BPF_K);
1884 s2->s.k = 2;
1885 sappend(s, s2);
1886
1887 /*
1888 * The A register now contains the length of the IP header.
1889 * We need to add to it the variable part of the offset of
1890 * the link-layer payload, which is still in the X
1891 * register, and move the result into the X register.
1892 */
1893 sappend(s, new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X));
1894 sappend(s, new_stmt(cstate, BPF_MISC|BPF_TAX));
1895 } else {
1896 /*
1897 * The offset of the link-layer payload is a constant,
1898 * so no code was generated to load the (non-existent)
1899 * variable part of that offset.
1900 *
1901 * This means we can use the 4*([k]&0xf) addressing
1902 * mode. Load the length of the IPv4 header, which
1903 * is at an offset of cstate->off_nl from the beginning of
1904 * the link-layer payload, and thus at an offset of
1905 * cstate->off_linkpl.constant_part + cstate->off_nl from the beginning
1906 * of the raw packet data, using that addressing mode.
1907 */
1908 s = new_stmt(cstate, BPF_LDX|BPF_MSH|BPF_B);
1909 s->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
1910 }
1911 return s;
1912 }
1913
1914
1915 static struct block *
gen_uncond(compiler_state_t * cstate,int rsense)1916 gen_uncond(compiler_state_t *cstate, int rsense)
1917 {
1918 struct block *b;
1919 struct slist *s;
1920
1921 s = new_stmt(cstate, BPF_LD|BPF_IMM);
1922 s->s.k = !rsense;
1923 b = new_block(cstate, JMP(BPF_JEQ));
1924 b->stmts = s;
1925
1926 return b;
1927 }
1928
1929 static inline struct block *
gen_true(compiler_state_t * cstate)1930 gen_true(compiler_state_t *cstate)
1931 {
1932 return gen_uncond(cstate, 1);
1933 }
1934
1935 static inline struct block *
gen_false(compiler_state_t * cstate)1936 gen_false(compiler_state_t *cstate)
1937 {
1938 return gen_uncond(cstate, 0);
1939 }
1940
1941 /*
1942 * Byte-swap a 32-bit number.
1943 * ("htonl()" or "ntohl()" won't work - we want to byte-swap even on
1944 * big-endian platforms.)
1945 */
1946 #define SWAPLONG(y) \
1947 ((((y)&0xff)<<24) | (((y)&0xff00)<<8) | (((y)&0xff0000)>>8) | (((y)>>24)&0xff))
1948
1949 /*
1950 * Generate code to match a particular packet type.
1951 *
1952 * "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP
1953 * value, if <= ETHERMTU. We use that to determine whether to
1954 * match the type/length field or to check the type/length field for
1955 * a value <= ETHERMTU to see whether it's a type field and then do
1956 * the appropriate test.
1957 */
1958 static struct block *
gen_ether_linktype(compiler_state_t * cstate,int proto)1959 gen_ether_linktype(compiler_state_t *cstate, int proto)
1960 {
1961 struct block *b0, *b1;
1962
1963 switch (proto) {
1964
1965 case LLCSAP_ISONS:
1966 case LLCSAP_IP:
1967 case LLCSAP_NETBEUI:
1968 /*
1969 * OSI protocols and NetBEUI always use 802.2 encapsulation,
1970 * so we check the DSAP and SSAP.
1971 *
1972 * LLCSAP_IP checks for IP-over-802.2, rather
1973 * than IP-over-Ethernet or IP-over-SNAP.
1974 *
1975 * XXX - should we check both the DSAP and the
1976 * SSAP, like this, or should we check just the
1977 * DSAP, as we do for other types <= ETHERMTU
1978 * (i.e., other SAP values)?
1979 */
1980 b0 = gen_cmp_gt(cstate, OR_LINKTYPE, 0, BPF_H, ETHERMTU);
1981 gen_not(b0);
1982 b1 = gen_cmp(cstate, OR_LLC, 0, BPF_H, (bpf_int32)
1983 ((proto << 8) | proto));
1984 gen_and(b0, b1);
1985 return b1;
1986
1987 case LLCSAP_IPX:
1988 /*
1989 * Check for;
1990 *
1991 * Ethernet_II frames, which are Ethernet
1992 * frames with a frame type of ETHERTYPE_IPX;
1993 *
1994 * Ethernet_802.3 frames, which are 802.3
1995 * frames (i.e., the type/length field is
1996 * a length field, <= ETHERMTU, rather than
1997 * a type field) with the first two bytes
1998 * after the Ethernet/802.3 header being
1999 * 0xFFFF;
2000 *
2001 * Ethernet_802.2 frames, which are 802.3
2002 * frames with an 802.2 LLC header and
2003 * with the IPX LSAP as the DSAP in the LLC
2004 * header;
2005 *
2006 * Ethernet_SNAP frames, which are 802.3
2007 * frames with an LLC header and a SNAP
2008 * header and with an OUI of 0x000000
2009 * (encapsulated Ethernet) and a protocol
2010 * ID of ETHERTYPE_IPX in the SNAP header.
2011 *
2012 * XXX - should we generate the same code both
2013 * for tests for LLCSAP_IPX and for ETHERTYPE_IPX?
2014 */
2015
2016 /*
2017 * This generates code to check both for the
2018 * IPX LSAP (Ethernet_802.2) and for Ethernet_802.3.
2019 */
2020 b0 = gen_cmp(cstate, OR_LLC, 0, BPF_B, (bpf_int32)LLCSAP_IPX);
2021 b1 = gen_cmp(cstate, OR_LLC, 0, BPF_H, (bpf_int32)0xFFFF);
2022 gen_or(b0, b1);
2023
2024 /*
2025 * Now we add code to check for SNAP frames with
2026 * ETHERTYPE_IPX, i.e. Ethernet_SNAP.
2027 */
2028 b0 = gen_snap(cstate, 0x000000, ETHERTYPE_IPX);
2029 gen_or(b0, b1);
2030
2031 /*
2032 * Now we generate code to check for 802.3
2033 * frames in general.
2034 */
2035 b0 = gen_cmp_gt(cstate, OR_LINKTYPE, 0, BPF_H, ETHERMTU);
2036 gen_not(b0);
2037
2038 /*
2039 * Now add the check for 802.3 frames before the
2040 * check for Ethernet_802.2 and Ethernet_802.3,
2041 * as those checks should only be done on 802.3
2042 * frames, not on Ethernet frames.
2043 */
2044 gen_and(b0, b1);
2045
2046 /*
2047 * Now add the check for Ethernet_II frames, and
2048 * do that before checking for the other frame
2049 * types.
2050 */
2051 b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)ETHERTYPE_IPX);
2052 gen_or(b0, b1);
2053 return b1;
2054
2055 case ETHERTYPE_ATALK:
2056 case ETHERTYPE_AARP:
2057 /*
2058 * EtherTalk (AppleTalk protocols on Ethernet link
2059 * layer) may use 802.2 encapsulation.
2060 */
2061
2062 /*
2063 * Check for 802.2 encapsulation (EtherTalk phase 2?);
2064 * we check for an Ethernet type field less than
2065 * 1500, which means it's an 802.3 length field.
2066 */
2067 b0 = gen_cmp_gt(cstate, OR_LINKTYPE, 0, BPF_H, ETHERMTU);
2068 gen_not(b0);
2069
2070 /*
2071 * 802.2-encapsulated ETHERTYPE_ATALK packets are
2072 * SNAP packets with an organization code of
2073 * 0x080007 (Apple, for Appletalk) and a protocol
2074 * type of ETHERTYPE_ATALK (Appletalk).
2075 *
2076 * 802.2-encapsulated ETHERTYPE_AARP packets are
2077 * SNAP packets with an organization code of
2078 * 0x000000 (encapsulated Ethernet) and a protocol
2079 * type of ETHERTYPE_AARP (Appletalk ARP).
2080 */
2081 if (proto == ETHERTYPE_ATALK)
2082 b1 = gen_snap(cstate, 0x080007, ETHERTYPE_ATALK);
2083 else /* proto == ETHERTYPE_AARP */
2084 b1 = gen_snap(cstate, 0x000000, ETHERTYPE_AARP);
2085 gen_and(b0, b1);
2086
2087 /*
2088 * Check for Ethernet encapsulation (Ethertalk
2089 * phase 1?); we just check for the Ethernet
2090 * protocol type.
2091 */
2092 b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)proto);
2093
2094 gen_or(b0, b1);
2095 return b1;
2096
2097 default:
2098 if (proto <= ETHERMTU) {
2099 /*
2100 * This is an LLC SAP value, so the frames
2101 * that match would be 802.2 frames.
2102 * Check that the frame is an 802.2 frame
2103 * (i.e., that the length/type field is
2104 * a length field, <= ETHERMTU) and
2105 * then check the DSAP.
2106 */
2107 b0 = gen_cmp_gt(cstate, OR_LINKTYPE, 0, BPF_H, ETHERMTU);
2108 gen_not(b0);
2109 b1 = gen_cmp(cstate, OR_LINKTYPE, 2, BPF_B, (bpf_int32)proto);
2110 gen_and(b0, b1);
2111 return b1;
2112 } else {
2113 /*
2114 * This is an Ethernet type, so compare
2115 * the length/type field with it (if
2116 * the frame is an 802.2 frame, the length
2117 * field will be <= ETHERMTU, and, as
2118 * "proto" is > ETHERMTU, this test
2119 * will fail and the frame won't match,
2120 * which is what we want).
2121 */
2122 return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H,
2123 (bpf_int32)proto);
2124 }
2125 }
2126 }
2127
2128 static struct block *
gen_loopback_linktype(compiler_state_t * cstate,int proto)2129 gen_loopback_linktype(compiler_state_t *cstate, int proto)
2130 {
2131 /*
2132 * For DLT_NULL, the link-layer header is a 32-bit word
2133 * containing an AF_ value in *host* byte order, and for
2134 * DLT_ENC, the link-layer header begins with a 32-bit
2135 * word containing an AF_ value in host byte order.
2136 *
2137 * In addition, if we're reading a saved capture file,
2138 * the host byte order in the capture may not be the
2139 * same as the host byte order on this machine.
2140 *
2141 * For DLT_LOOP, the link-layer header is a 32-bit
2142 * word containing an AF_ value in *network* byte order.
2143 */
2144 if (cstate->linktype == DLT_NULL || cstate->linktype == DLT_ENC) {
2145 /*
2146 * The AF_ value is in host byte order, but the BPF
2147 * interpreter will convert it to network byte order.
2148 *
2149 * If this is a save file, and it's from a machine
2150 * with the opposite byte order to ours, we byte-swap
2151 * the AF_ value.
2152 *
2153 * Then we run it through "htonl()", and generate
2154 * code to compare against the result.
2155 */
2156 if (cstate->bpf_pcap->rfile != NULL && cstate->bpf_pcap->swapped)
2157 proto = SWAPLONG(proto);
2158 proto = htonl(proto);
2159 }
2160 return (gen_cmp(cstate, OR_LINKHDR, 0, BPF_W, (bpf_int32)proto));
2161 }
2162
2163 /*
2164 * "proto" is an Ethernet type value and for IPNET, if it is not IPv4
2165 * or IPv6 then we have an error.
2166 */
2167 static struct block *
gen_ipnet_linktype(compiler_state_t * cstate,int proto)2168 gen_ipnet_linktype(compiler_state_t *cstate, int proto)
2169 {
2170 switch (proto) {
2171
2172 case ETHERTYPE_IP:
2173 return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B, (bpf_int32)IPH_AF_INET);
2174 /*NOTREACHED*/
2175
2176 case ETHERTYPE_IPV6:
2177 return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
2178 (bpf_int32)IPH_AF_INET6);
2179 /*NOTREACHED*/
2180
2181 default:
2182 break;
2183 }
2184
2185 return gen_false(cstate);
2186 }
2187
2188 /*
2189 * Generate code to match a particular packet type.
2190 *
2191 * "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP
2192 * value, if <= ETHERMTU. We use that to determine whether to
2193 * match the type field or to check the type field for the special
2194 * LINUX_SLL_P_802_2 value and then do the appropriate test.
2195 */
2196 static struct block *
gen_linux_sll_linktype(compiler_state_t * cstate,int proto)2197 gen_linux_sll_linktype(compiler_state_t *cstate, int proto)
2198 {
2199 struct block *b0, *b1;
2200
2201 switch (proto) {
2202
2203 case LLCSAP_ISONS:
2204 case LLCSAP_IP:
2205 case LLCSAP_NETBEUI:
2206 /*
2207 * OSI protocols and NetBEUI always use 802.2 encapsulation,
2208 * so we check the DSAP and SSAP.
2209 *
2210 * LLCSAP_IP checks for IP-over-802.2, rather
2211 * than IP-over-Ethernet or IP-over-SNAP.
2212 *
2213 * XXX - should we check both the DSAP and the
2214 * SSAP, like this, or should we check just the
2215 * DSAP, as we do for other types <= ETHERMTU
2216 * (i.e., other SAP values)?
2217 */
2218 b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, LINUX_SLL_P_802_2);
2219 b1 = gen_cmp(cstate, OR_LLC, 0, BPF_H, (bpf_int32)
2220 ((proto << 8) | proto));
2221 gen_and(b0, b1);
2222 return b1;
2223
2224 case LLCSAP_IPX:
2225 /*
2226 * Ethernet_II frames, which are Ethernet
2227 * frames with a frame type of ETHERTYPE_IPX;
2228 *
2229 * Ethernet_802.3 frames, which have a frame
2230 * type of LINUX_SLL_P_802_3;
2231 *
2232 * Ethernet_802.2 frames, which are 802.3
2233 * frames with an 802.2 LLC header (i.e, have
2234 * a frame type of LINUX_SLL_P_802_2) and
2235 * with the IPX LSAP as the DSAP in the LLC
2236 * header;
2237 *
2238 * Ethernet_SNAP frames, which are 802.3
2239 * frames with an LLC header and a SNAP
2240 * header and with an OUI of 0x000000
2241 * (encapsulated Ethernet) and a protocol
2242 * ID of ETHERTYPE_IPX in the SNAP header.
2243 *
2244 * First, do the checks on LINUX_SLL_P_802_2
2245 * frames; generate the check for either
2246 * Ethernet_802.2 or Ethernet_SNAP frames, and
2247 * then put a check for LINUX_SLL_P_802_2 frames
2248 * before it.
2249 */
2250 b0 = gen_cmp(cstate, OR_LLC, 0, BPF_B, (bpf_int32)LLCSAP_IPX);
2251 b1 = gen_snap(cstate, 0x000000, ETHERTYPE_IPX);
2252 gen_or(b0, b1);
2253 b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, LINUX_SLL_P_802_2);
2254 gen_and(b0, b1);
2255
2256 /*
2257 * Now check for 802.3 frames and OR that with
2258 * the previous test.
2259 */
2260 b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, LINUX_SLL_P_802_3);
2261 gen_or(b0, b1);
2262
2263 /*
2264 * Now add the check for Ethernet_II frames, and
2265 * do that before checking for the other frame
2266 * types.
2267 */
2268 b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)ETHERTYPE_IPX);
2269 gen_or(b0, b1);
2270 return b1;
2271
2272 case ETHERTYPE_ATALK:
2273 case ETHERTYPE_AARP:
2274 /*
2275 * EtherTalk (AppleTalk protocols on Ethernet link
2276 * layer) may use 802.2 encapsulation.
2277 */
2278
2279 /*
2280 * Check for 802.2 encapsulation (EtherTalk phase 2?);
2281 * we check for the 802.2 protocol type in the
2282 * "Ethernet type" field.
2283 */
2284 b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, LINUX_SLL_P_802_2);
2285
2286 /*
2287 * 802.2-encapsulated ETHERTYPE_ATALK packets are
2288 * SNAP packets with an organization code of
2289 * 0x080007 (Apple, for Appletalk) and a protocol
2290 * type of ETHERTYPE_ATALK (Appletalk).
2291 *
2292 * 802.2-encapsulated ETHERTYPE_AARP packets are
2293 * SNAP packets with an organization code of
2294 * 0x000000 (encapsulated Ethernet) and a protocol
2295 * type of ETHERTYPE_AARP (Appletalk ARP).
2296 */
2297 if (proto == ETHERTYPE_ATALK)
2298 b1 = gen_snap(cstate, 0x080007, ETHERTYPE_ATALK);
2299 else /* proto == ETHERTYPE_AARP */
2300 b1 = gen_snap(cstate, 0x000000, ETHERTYPE_AARP);
2301 gen_and(b0, b1);
2302
2303 /*
2304 * Check for Ethernet encapsulation (Ethertalk
2305 * phase 1?); we just check for the Ethernet
2306 * protocol type.
2307 */
2308 b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)proto);
2309
2310 gen_or(b0, b1);
2311 return b1;
2312
2313 default:
2314 if (proto <= ETHERMTU) {
2315 /*
2316 * This is an LLC SAP value, so the frames
2317 * that match would be 802.2 frames.
2318 * Check for the 802.2 protocol type
2319 * in the "Ethernet type" field, and
2320 * then check the DSAP.
2321 */
2322 b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, LINUX_SLL_P_802_2);
2323 b1 = gen_cmp(cstate, OR_LINKHDR, cstate->off_linkpl.constant_part, BPF_B,
2324 (bpf_int32)proto);
2325 gen_and(b0, b1);
2326 return b1;
2327 } else {
2328 /*
2329 * This is an Ethernet type, so compare
2330 * the length/type field with it (if
2331 * the frame is an 802.2 frame, the length
2332 * field will be <= ETHERMTU, and, as
2333 * "proto" is > ETHERMTU, this test
2334 * will fail and the frame won't match,
2335 * which is what we want).
2336 */
2337 return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)proto);
2338 }
2339 }
2340 }
2341
2342 static struct slist *
gen_load_prism_llprefixlen(compiler_state_t * cstate)2343 gen_load_prism_llprefixlen(compiler_state_t *cstate)
2344 {
2345 struct slist *s1, *s2;
2346 struct slist *sjeq_avs_cookie;
2347 struct slist *sjcommon;
2348
2349 /*
2350 * This code is not compatible with the optimizer, as
2351 * we are generating jmp instructions within a normal
2352 * slist of instructions
2353 */
2354 cstate->no_optimize = 1;
2355
2356 /*
2357 * Generate code to load the length of the radio header into
2358 * the register assigned to hold that length, if one has been
2359 * assigned. (If one hasn't been assigned, no code we've
2360 * generated uses that prefix, so we don't need to generate any
2361 * code to load it.)
2362 *
2363 * Some Linux drivers use ARPHRD_IEEE80211_PRISM but sometimes
2364 * or always use the AVS header rather than the Prism header.
2365 * We load a 4-byte big-endian value at the beginning of the
2366 * raw packet data, and see whether, when masked with 0xFFFFF000,
2367 * it's equal to 0x80211000. If so, that indicates that it's
2368 * an AVS header (the masked-out bits are the version number).
2369 * Otherwise, it's a Prism header.
2370 *
2371 * XXX - the Prism header is also, in theory, variable-length,
2372 * but no known software generates headers that aren't 144
2373 * bytes long.
2374 */
2375 if (cstate->off_linkhdr.reg != -1) {
2376 /*
2377 * Load the cookie.
2378 */
2379 s1 = new_stmt(cstate, BPF_LD|BPF_W|BPF_ABS);
2380 s1->s.k = 0;
2381
2382 /*
2383 * AND it with 0xFFFFF000.
2384 */
2385 s2 = new_stmt(cstate, BPF_ALU|BPF_AND|BPF_K);
2386 s2->s.k = 0xFFFFF000;
2387 sappend(s1, s2);
2388
2389 /*
2390 * Compare with 0x80211000.
2391 */
2392 sjeq_avs_cookie = new_stmt(cstate, JMP(BPF_JEQ));
2393 sjeq_avs_cookie->s.k = 0x80211000;
2394 sappend(s1, sjeq_avs_cookie);
2395
2396 /*
2397 * If it's AVS:
2398 *
2399 * The 4 bytes at an offset of 4 from the beginning of
2400 * the AVS header are the length of the AVS header.
2401 * That field is big-endian.
2402 */
2403 s2 = new_stmt(cstate, BPF_LD|BPF_W|BPF_ABS);
2404 s2->s.k = 4;
2405 sappend(s1, s2);
2406 sjeq_avs_cookie->s.jt = s2;
2407
2408 /*
2409 * Now jump to the code to allocate a register
2410 * into which to save the header length and
2411 * store the length there. (The "jump always"
2412 * instruction needs to have the k field set;
2413 * it's added to the PC, so, as we're jumping
2414 * over a single instruction, it should be 1.)
2415 */
2416 sjcommon = new_stmt(cstate, JMP(BPF_JA));
2417 sjcommon->s.k = 1;
2418 sappend(s1, sjcommon);
2419
2420 /*
2421 * Now for the code that handles the Prism header.
2422 * Just load the length of the Prism header (144)
2423 * into the A register. Have the test for an AVS
2424 * header branch here if we don't have an AVS header.
2425 */
2426 s2 = new_stmt(cstate, BPF_LD|BPF_W|BPF_IMM);
2427 s2->s.k = 144;
2428 sappend(s1, s2);
2429 sjeq_avs_cookie->s.jf = s2;
2430
2431 /*
2432 * Now allocate a register to hold that value and store
2433 * it. The code for the AVS header will jump here after
2434 * loading the length of the AVS header.
2435 */
2436 s2 = new_stmt(cstate, BPF_ST);
2437 s2->s.k = cstate->off_linkhdr.reg;
2438 sappend(s1, s2);
2439 sjcommon->s.jf = s2;
2440
2441 /*
2442 * Now move it into the X register.
2443 */
2444 s2 = new_stmt(cstate, BPF_MISC|BPF_TAX);
2445 sappend(s1, s2);
2446
2447 return (s1);
2448 } else
2449 return (NULL);
2450 }
2451
2452 static struct slist *
gen_load_avs_llprefixlen(compiler_state_t * cstate)2453 gen_load_avs_llprefixlen(compiler_state_t *cstate)
2454 {
2455 struct slist *s1, *s2;
2456
2457 /*
2458 * Generate code to load the length of the AVS header into
2459 * the register assigned to hold that length, if one has been
2460 * assigned. (If one hasn't been assigned, no code we've
2461 * generated uses that prefix, so we don't need to generate any
2462 * code to load it.)
2463 */
2464 if (cstate->off_linkhdr.reg != -1) {
2465 /*
2466 * The 4 bytes at an offset of 4 from the beginning of
2467 * the AVS header are the length of the AVS header.
2468 * That field is big-endian.
2469 */
2470 s1 = new_stmt(cstate, BPF_LD|BPF_W|BPF_ABS);
2471 s1->s.k = 4;
2472
2473 /*
2474 * Now allocate a register to hold that value and store
2475 * it.
2476 */
2477 s2 = new_stmt(cstate, BPF_ST);
2478 s2->s.k = cstate->off_linkhdr.reg;
2479 sappend(s1, s2);
2480
2481 /*
2482 * Now move it into the X register.
2483 */
2484 s2 = new_stmt(cstate, BPF_MISC|BPF_TAX);
2485 sappend(s1, s2);
2486
2487 return (s1);
2488 } else
2489 return (NULL);
2490 }
2491
2492 static struct slist *
gen_load_radiotap_llprefixlen(compiler_state_t * cstate)2493 gen_load_radiotap_llprefixlen(compiler_state_t *cstate)
2494 {
2495 struct slist *s1, *s2;
2496
2497 /*
2498 * Generate code to load the length of the radiotap header into
2499 * the register assigned to hold that length, if one has been
2500 * assigned. (If one hasn't been assigned, no code we've
2501 * generated uses that prefix, so we don't need to generate any
2502 * code to load it.)
2503 */
2504 if (cstate->off_linkhdr.reg != -1) {
2505 /*
2506 * The 2 bytes at offsets of 2 and 3 from the beginning
2507 * of the radiotap header are the length of the radiotap
2508 * header; unfortunately, it's little-endian, so we have
2509 * to load it a byte at a time and construct the value.
2510 */
2511
2512 /*
2513 * Load the high-order byte, at an offset of 3, shift it
2514 * left a byte, and put the result in the X register.
2515 */
2516 s1 = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS);
2517 s1->s.k = 3;
2518 s2 = new_stmt(cstate, BPF_ALU|BPF_LSH|BPF_K);
2519 sappend(s1, s2);
2520 s2->s.k = 8;
2521 s2 = new_stmt(cstate, BPF_MISC|BPF_TAX);
2522 sappend(s1, s2);
2523
2524 /*
2525 * Load the next byte, at an offset of 2, and OR the
2526 * value from the X register into it.
2527 */
2528 s2 = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS);
2529 sappend(s1, s2);
2530 s2->s.k = 2;
2531 s2 = new_stmt(cstate, BPF_ALU|BPF_OR|BPF_X);
2532 sappend(s1, s2);
2533
2534 /*
2535 * Now allocate a register to hold that value and store
2536 * it.
2537 */
2538 s2 = new_stmt(cstate, BPF_ST);
2539 s2->s.k = cstate->off_linkhdr.reg;
2540 sappend(s1, s2);
2541
2542 /*
2543 * Now move it into the X register.
2544 */
2545 s2 = new_stmt(cstate, BPF_MISC|BPF_TAX);
2546 sappend(s1, s2);
2547
2548 return (s1);
2549 } else
2550 return (NULL);
2551 }
2552
2553 /*
2554 * At the moment we treat PPI as normal Radiotap encoded
2555 * packets. The difference is in the function that generates
2556 * the code at the beginning to compute the header length.
2557 * Since this code generator of PPI supports bare 802.11
2558 * encapsulation only (i.e. the encapsulated DLT should be
2559 * DLT_IEEE802_11) we generate code to check for this too;
2560 * that's done in finish_parse().
2561 */
2562 static struct slist *
gen_load_ppi_llprefixlen(compiler_state_t * cstate)2563 gen_load_ppi_llprefixlen(compiler_state_t *cstate)
2564 {
2565 struct slist *s1, *s2;
2566
2567 /*
2568 * Generate code to load the length of the radiotap header
2569 * into the register assigned to hold that length, if one has
2570 * been assigned.
2571 */
2572 if (cstate->off_linkhdr.reg != -1) {
2573 /*
2574 * The 2 bytes at offsets of 2 and 3 from the beginning
2575 * of the radiotap header are the length of the radiotap
2576 * header; unfortunately, it's little-endian, so we have
2577 * to load it a byte at a time and construct the value.
2578 */
2579
2580 /*
2581 * Load the high-order byte, at an offset of 3, shift it
2582 * left a byte, and put the result in the X register.
2583 */
2584 s1 = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS);
2585 s1->s.k = 3;
2586 s2 = new_stmt(cstate, BPF_ALU|BPF_LSH|BPF_K);
2587 sappend(s1, s2);
2588 s2->s.k = 8;
2589 s2 = new_stmt(cstate, BPF_MISC|BPF_TAX);
2590 sappend(s1, s2);
2591
2592 /*
2593 * Load the next byte, at an offset of 2, and OR the
2594 * value from the X register into it.
2595 */
2596 s2 = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS);
2597 sappend(s1, s2);
2598 s2->s.k = 2;
2599 s2 = new_stmt(cstate, BPF_ALU|BPF_OR|BPF_X);
2600 sappend(s1, s2);
2601
2602 /*
2603 * Now allocate a register to hold that value and store
2604 * it.
2605 */
2606 s2 = new_stmt(cstate, BPF_ST);
2607 s2->s.k = cstate->off_linkhdr.reg;
2608 sappend(s1, s2);
2609
2610 /*
2611 * Now move it into the X register.
2612 */
2613 s2 = new_stmt(cstate, BPF_MISC|BPF_TAX);
2614 sappend(s1, s2);
2615
2616 return (s1);
2617 } else
2618 return (NULL);
2619 }
2620
2621 /*
2622 * Load a value relative to the beginning of the link-layer header after the 802.11
2623 * header, i.e. LLC_SNAP.
2624 * The link-layer header doesn't necessarily begin at the beginning
2625 * of the packet data; there might be a variable-length prefix containing
2626 * radio information.
2627 */
2628 static struct slist *
gen_load_802_11_header_len(compiler_state_t * cstate,struct slist * s,struct slist * snext)2629 gen_load_802_11_header_len(compiler_state_t *cstate, struct slist *s, struct slist *snext)
2630 {
2631 struct slist *s2;
2632 struct slist *sjset_data_frame_1;
2633 struct slist *sjset_data_frame_2;
2634 struct slist *sjset_qos;
2635 struct slist *sjset_radiotap_flags_present;
2636 struct slist *sjset_radiotap_ext_present;
2637 struct slist *sjset_radiotap_tsft_present;
2638 struct slist *sjset_tsft_datapad, *sjset_notsft_datapad;
2639 struct slist *s_roundup;
2640
2641 if (cstate->off_linkpl.reg == -1) {
2642 /*
2643 * No register has been assigned to the offset of
2644 * the link-layer payload, which means nobody needs
2645 * it; don't bother computing it - just return
2646 * what we already have.
2647 */
2648 return (s);
2649 }
2650
2651 /*
2652 * This code is not compatible with the optimizer, as
2653 * we are generating jmp instructions within a normal
2654 * slist of instructions
2655 */
2656 cstate->no_optimize = 1;
2657
2658 /*
2659 * If "s" is non-null, it has code to arrange that the X register
2660 * contains the length of the prefix preceding the link-layer
2661 * header.
2662 *
2663 * Otherwise, the length of the prefix preceding the link-layer
2664 * header is "off_outermostlinkhdr.constant_part".
2665 */
2666 if (s == NULL) {
2667 /*
2668 * There is no variable-length header preceding the
2669 * link-layer header.
2670 *
2671 * Load the length of the fixed-length prefix preceding
2672 * the link-layer header (if any) into the X register,
2673 * and store it in the cstate->off_linkpl.reg register.
2674 * That length is off_outermostlinkhdr.constant_part.
2675 */
2676 s = new_stmt(cstate, BPF_LDX|BPF_IMM);
2677 s->s.k = cstate->off_outermostlinkhdr.constant_part;
2678 }
2679
2680 /*
2681 * The X register contains the offset of the beginning of the
2682 * link-layer header; add 24, which is the minimum length
2683 * of the MAC header for a data frame, to that, and store it
2684 * in cstate->off_linkpl.reg, and then load the Frame Control field,
2685 * which is at the offset in the X register, with an indexed load.
2686 */
2687 s2 = new_stmt(cstate, BPF_MISC|BPF_TXA);
2688 sappend(s, s2);
2689 s2 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
2690 s2->s.k = 24;
2691 sappend(s, s2);
2692 s2 = new_stmt(cstate, BPF_ST);
2693 s2->s.k = cstate->off_linkpl.reg;
2694 sappend(s, s2);
2695
2696 s2 = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B);
2697 s2->s.k = 0;
2698 sappend(s, s2);
2699
2700 /*
2701 * Check the Frame Control field to see if this is a data frame;
2702 * a data frame has the 0x08 bit (b3) in that field set and the
2703 * 0x04 bit (b2) clear.
2704 */
2705 sjset_data_frame_1 = new_stmt(cstate, JMP(BPF_JSET));
2706 sjset_data_frame_1->s.k = 0x08;
2707 sappend(s, sjset_data_frame_1);
2708
2709 /*
2710 * If b3 is set, test b2, otherwise go to the first statement of
2711 * the rest of the program.
2712 */
2713 sjset_data_frame_1->s.jt = sjset_data_frame_2 = new_stmt(cstate, JMP(BPF_JSET));
2714 sjset_data_frame_2->s.k = 0x04;
2715 sappend(s, sjset_data_frame_2);
2716 sjset_data_frame_1->s.jf = snext;
2717
2718 /*
2719 * If b2 is not set, this is a data frame; test the QoS bit.
2720 * Otherwise, go to the first statement of the rest of the
2721 * program.
2722 */
2723 sjset_data_frame_2->s.jt = snext;
2724 sjset_data_frame_2->s.jf = sjset_qos = new_stmt(cstate, JMP(BPF_JSET));
2725 sjset_qos->s.k = 0x80; /* QoS bit */
2726 sappend(s, sjset_qos);
2727
2728 /*
2729 * If it's set, add 2 to cstate->off_linkpl.reg, to skip the QoS
2730 * field.
2731 * Otherwise, go to the first statement of the rest of the
2732 * program.
2733 */
2734 sjset_qos->s.jt = s2 = new_stmt(cstate, BPF_LD|BPF_MEM);
2735 s2->s.k = cstate->off_linkpl.reg;
2736 sappend(s, s2);
2737 s2 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_IMM);
2738 s2->s.k = 2;
2739 sappend(s, s2);
2740 s2 = new_stmt(cstate, BPF_ST);
2741 s2->s.k = cstate->off_linkpl.reg;
2742 sappend(s, s2);
2743
2744 /*
2745 * If we have a radiotap header, look at it to see whether
2746 * there's Atheros padding between the MAC-layer header
2747 * and the payload.
2748 *
2749 * Note: all of the fields in the radiotap header are
2750 * little-endian, so we byte-swap all of the values
2751 * we test against, as they will be loaded as big-endian
2752 * values.
2753 *
2754 * XXX - in the general case, we would have to scan through
2755 * *all* the presence bits, if there's more than one word of
2756 * presence bits. That would require a loop, meaning that
2757 * we wouldn't be able to run the filter in the kernel.
2758 *
2759 * We assume here that the Atheros adapters that insert the
2760 * annoying padding don't have multiple antennae and therefore
2761 * do not generate radiotap headers with multiple presence words.
2762 */
2763 if (cstate->linktype == DLT_IEEE802_11_RADIO) {
2764 /*
2765 * Is the IEEE80211_RADIOTAP_FLAGS bit (0x0000002) set
2766 * in the first presence flag word?
2767 */
2768 sjset_qos->s.jf = s2 = new_stmt(cstate, BPF_LD|BPF_ABS|BPF_W);
2769 s2->s.k = 4;
2770 sappend(s, s2);
2771
2772 sjset_radiotap_flags_present = new_stmt(cstate, JMP(BPF_JSET));
2773 sjset_radiotap_flags_present->s.k = SWAPLONG(0x00000002);
2774 sappend(s, sjset_radiotap_flags_present);
2775
2776 /*
2777 * If not, skip all of this.
2778 */
2779 sjset_radiotap_flags_present->s.jf = snext;
2780
2781 /*
2782 * Otherwise, is the "extension" bit set in that word?
2783 */
2784 sjset_radiotap_ext_present = new_stmt(cstate, JMP(BPF_JSET));
2785 sjset_radiotap_ext_present->s.k = SWAPLONG(0x80000000);
2786 sappend(s, sjset_radiotap_ext_present);
2787 sjset_radiotap_flags_present->s.jt = sjset_radiotap_ext_present;
2788
2789 /*
2790 * If so, skip all of this.
2791 */
2792 sjset_radiotap_ext_present->s.jt = snext;
2793
2794 /*
2795 * Otherwise, is the IEEE80211_RADIOTAP_TSFT bit set?
2796 */
2797 sjset_radiotap_tsft_present = new_stmt(cstate, JMP(BPF_JSET));
2798 sjset_radiotap_tsft_present->s.k = SWAPLONG(0x00000001);
2799 sappend(s, sjset_radiotap_tsft_present);
2800 sjset_radiotap_ext_present->s.jf = sjset_radiotap_tsft_present;
2801
2802 /*
2803 * If IEEE80211_RADIOTAP_TSFT is set, the flags field is
2804 * at an offset of 16 from the beginning of the raw packet
2805 * data (8 bytes for the radiotap header and 8 bytes for
2806 * the TSFT field).
2807 *
2808 * Test whether the IEEE80211_RADIOTAP_F_DATAPAD bit (0x20)
2809 * is set.
2810 */
2811 s2 = new_stmt(cstate, BPF_LD|BPF_ABS|BPF_B);
2812 s2->s.k = 16;
2813 sappend(s, s2);
2814 sjset_radiotap_tsft_present->s.jt = s2;
2815
2816 sjset_tsft_datapad = new_stmt(cstate, JMP(BPF_JSET));
2817 sjset_tsft_datapad->s.k = 0x20;
2818 sappend(s, sjset_tsft_datapad);
2819
2820 /*
2821 * If IEEE80211_RADIOTAP_TSFT is not set, the flags field is
2822 * at an offset of 8 from the beginning of the raw packet
2823 * data (8 bytes for the radiotap header).
2824 *
2825 * Test whether the IEEE80211_RADIOTAP_F_DATAPAD bit (0x20)
2826 * is set.
2827 */
2828 s2 = new_stmt(cstate, BPF_LD|BPF_ABS|BPF_B);
2829 s2->s.k = 8;
2830 sappend(s, s2);
2831 sjset_radiotap_tsft_present->s.jf = s2;
2832
2833 sjset_notsft_datapad = new_stmt(cstate, JMP(BPF_JSET));
2834 sjset_notsft_datapad->s.k = 0x20;
2835 sappend(s, sjset_notsft_datapad);
2836
2837 /*
2838 * In either case, if IEEE80211_RADIOTAP_F_DATAPAD is
2839 * set, round the length of the 802.11 header to
2840 * a multiple of 4. Do that by adding 3 and then
2841 * dividing by and multiplying by 4, which we do by
2842 * ANDing with ~3.
2843 */
2844 s_roundup = new_stmt(cstate, BPF_LD|BPF_MEM);
2845 s_roundup->s.k = cstate->off_linkpl.reg;
2846 sappend(s, s_roundup);
2847 s2 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_IMM);
2848 s2->s.k = 3;
2849 sappend(s, s2);
2850 s2 = new_stmt(cstate, BPF_ALU|BPF_AND|BPF_IMM);
2851 s2->s.k = ~3;
2852 sappend(s, s2);
2853 s2 = new_stmt(cstate, BPF_ST);
2854 s2->s.k = cstate->off_linkpl.reg;
2855 sappend(s, s2);
2856
2857 sjset_tsft_datapad->s.jt = s_roundup;
2858 sjset_tsft_datapad->s.jf = snext;
2859 sjset_notsft_datapad->s.jt = s_roundup;
2860 sjset_notsft_datapad->s.jf = snext;
2861 } else
2862 sjset_qos->s.jf = snext;
2863
2864 return s;
2865 }
2866
2867 static void
insert_compute_vloffsets(compiler_state_t * cstate,struct block * b)2868 insert_compute_vloffsets(compiler_state_t *cstate, struct block *b)
2869 {
2870 struct slist *s;
2871
2872 /* There is an implicit dependency between the link
2873 * payload and link header since the payload computation
2874 * includes the variable part of the header. Therefore,
2875 * if nobody else has allocated a register for the link
2876 * header and we need it, do it now. */
2877 if (cstate->off_linkpl.reg != -1 && cstate->off_linkhdr.is_variable &&
2878 cstate->off_linkhdr.reg == -1)
2879 cstate->off_linkhdr.reg = alloc_reg(cstate);
2880
2881 /*
2882 * For link-layer types that have a variable-length header
2883 * preceding the link-layer header, generate code to load
2884 * the offset of the link-layer header into the register
2885 * assigned to that offset, if any.
2886 *
2887 * XXX - this, and the next switch statement, won't handle
2888 * encapsulation of 802.11 or 802.11+radio information in
2889 * some other protocol stack. That's significantly more
2890 * complicated.
2891 */
2892 switch (cstate->outermostlinktype) {
2893
2894 case DLT_PRISM_HEADER:
2895 s = gen_load_prism_llprefixlen(cstate);
2896 break;
2897
2898 case DLT_IEEE802_11_RADIO_AVS:
2899 s = gen_load_avs_llprefixlen(cstate);
2900 break;
2901
2902 case DLT_IEEE802_11_RADIO:
2903 s = gen_load_radiotap_llprefixlen(cstate);
2904 break;
2905
2906 case DLT_PPI:
2907 s = gen_load_ppi_llprefixlen(cstate);
2908 break;
2909
2910 default:
2911 s = NULL;
2912 break;
2913 }
2914
2915 /*
2916 * For link-layer types that have a variable-length link-layer
2917 * header, generate code to load the offset of the link-layer
2918 * payload into the register assigned to that offset, if any.
2919 */
2920 switch (cstate->outermostlinktype) {
2921
2922 case DLT_IEEE802_11:
2923 case DLT_PRISM_HEADER:
2924 case DLT_IEEE802_11_RADIO_AVS:
2925 case DLT_IEEE802_11_RADIO:
2926 case DLT_PPI:
2927 s = gen_load_802_11_header_len(cstate, s, b->stmts);
2928 break;
2929 }
2930
2931 /*
2932 * If there there is no initialization yet and we need variable
2933 * length offsets for VLAN, initialize them to zero
2934 */
2935 if (s == NULL && cstate->is_vlan_vloffset) {
2936 struct slist *s2;
2937
2938 if (cstate->off_linkpl.reg == -1)
2939 cstate->off_linkpl.reg = alloc_reg(cstate);
2940 if (cstate->off_linktype.reg == -1)
2941 cstate->off_linktype.reg = alloc_reg(cstate);
2942
2943 s = new_stmt(cstate, BPF_LD|BPF_W|BPF_IMM);
2944 s->s.k = 0;
2945 s2 = new_stmt(cstate, BPF_ST);
2946 s2->s.k = cstate->off_linkpl.reg;
2947 sappend(s, s2);
2948 s2 = new_stmt(cstate, BPF_ST);
2949 s2->s.k = cstate->off_linktype.reg;
2950 sappend(s, s2);
2951 }
2952
2953 /*
2954 * If we have any offset-loading code, append all the
2955 * existing statements in the block to those statements,
2956 * and make the resulting list the list of statements
2957 * for the block.
2958 */
2959 if (s != NULL) {
2960 sappend(s, b->stmts);
2961 b->stmts = s;
2962 }
2963 }
2964
2965 static struct block *
gen_ppi_dlt_check(compiler_state_t * cstate)2966 gen_ppi_dlt_check(compiler_state_t *cstate)
2967 {
2968 struct slist *s_load_dlt;
2969 struct block *b;
2970
2971 if (cstate->linktype == DLT_PPI)
2972 {
2973 /* Create the statements that check for the DLT
2974 */
2975 s_load_dlt = new_stmt(cstate, BPF_LD|BPF_W|BPF_ABS);
2976 s_load_dlt->s.k = 4;
2977
2978 b = new_block(cstate, JMP(BPF_JEQ));
2979
2980 b->stmts = s_load_dlt;
2981 b->s.k = SWAPLONG(DLT_IEEE802_11);
2982 }
2983 else
2984 {
2985 b = NULL;
2986 }
2987
2988 return b;
2989 }
2990
2991 /*
2992 * Take an absolute offset, and:
2993 *
2994 * if it has no variable part, return NULL;
2995 *
2996 * if it has a variable part, generate code to load the register
2997 * containing that variable part into the X register, returning
2998 * a pointer to that code - if no register for that offset has
2999 * been allocated, allocate it first.
3000 *
3001 * (The code to set that register will be generated later, but will
3002 * be placed earlier in the code sequence.)
3003 */
3004 static struct slist *
gen_abs_offset_varpart(compiler_state_t * cstate,bpf_abs_offset * off)3005 gen_abs_offset_varpart(compiler_state_t *cstate, bpf_abs_offset *off)
3006 {
3007 struct slist *s;
3008
3009 if (off->is_variable) {
3010 if (off->reg == -1) {
3011 /*
3012 * We haven't yet assigned a register for the
3013 * variable part of the offset of the link-layer
3014 * header; allocate one.
3015 */
3016 off->reg = alloc_reg(cstate);
3017 }
3018
3019 /*
3020 * Load the register containing the variable part of the
3021 * offset of the link-layer header into the X register.
3022 */
3023 s = new_stmt(cstate, BPF_LDX|BPF_MEM);
3024 s->s.k = off->reg;
3025 return s;
3026 } else {
3027 /*
3028 * That offset isn't variable, there's no variable part,
3029 * so we don't need to generate any code.
3030 */
3031 return NULL;
3032 }
3033 }
3034
3035 /*
3036 * Map an Ethernet type to the equivalent PPP type.
3037 */
3038 static int
ethertype_to_ppptype(int proto)3039 ethertype_to_ppptype(int proto)
3040 {
3041 switch (proto) {
3042
3043 case ETHERTYPE_IP:
3044 proto = PPP_IP;
3045 break;
3046
3047 case ETHERTYPE_IPV6:
3048 proto = PPP_IPV6;
3049 break;
3050
3051 case ETHERTYPE_DN:
3052 proto = PPP_DECNET;
3053 break;
3054
3055 case ETHERTYPE_ATALK:
3056 proto = PPP_APPLE;
3057 break;
3058
3059 case ETHERTYPE_NS:
3060 proto = PPP_NS;
3061 break;
3062
3063 case LLCSAP_ISONS:
3064 proto = PPP_OSI;
3065 break;
3066
3067 case LLCSAP_8021D:
3068 /*
3069 * I'm assuming the "Bridging PDU"s that go
3070 * over PPP are Spanning Tree Protocol
3071 * Bridging PDUs.
3072 */
3073 proto = PPP_BRPDU;
3074 break;
3075
3076 case LLCSAP_IPX:
3077 proto = PPP_IPX;
3078 break;
3079 }
3080 return (proto);
3081 }
3082
3083 /*
3084 * Generate any tests that, for encapsulation of a link-layer packet
3085 * inside another protocol stack, need to be done to check for those
3086 * link-layer packets (and that haven't already been done by a check
3087 * for that encapsulation).
3088 */
3089 static struct block *
gen_prevlinkhdr_check(compiler_state_t * cstate)3090 gen_prevlinkhdr_check(compiler_state_t *cstate)
3091 {
3092 struct block *b0;
3093
3094 if (cstate->is_geneve)
3095 return gen_geneve_ll_check(cstate);
3096
3097 switch (cstate->prevlinktype) {
3098
3099 case DLT_SUNATM:
3100 /*
3101 * This is LANE-encapsulated Ethernet; check that the LANE
3102 * packet doesn't begin with an LE Control marker, i.e.
3103 * that it's data, not a control message.
3104 *
3105 * (We've already generated a test for LANE.)
3106 */
3107 b0 = gen_cmp(cstate, OR_PREVLINKHDR, SUNATM_PKT_BEGIN_POS, BPF_H, 0xFF00);
3108 gen_not(b0);
3109 return b0;
3110
3111 default:
3112 /*
3113 * No such tests are necessary.
3114 */
3115 return NULL;
3116 }
3117 /*NOTREACHED*/
3118 }
3119
3120 /*
3121 * The three different values we should check for when checking for an
3122 * IPv6 packet with DLT_NULL.
3123 */
3124 #define BSD_AFNUM_INET6_BSD 24 /* NetBSD, OpenBSD, BSD/OS, Npcap */
3125 #define BSD_AFNUM_INET6_FREEBSD 28 /* FreeBSD */
3126 #define BSD_AFNUM_INET6_DARWIN 30 /* macOS, iOS, other Darwin-based OSes */
3127
3128 /*
3129 * Generate code to match a particular packet type by matching the
3130 * link-layer type field or fields in the 802.2 LLC header.
3131 *
3132 * "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP
3133 * value, if <= ETHERMTU.
3134 */
3135 static struct block *
gen_linktype(compiler_state_t * cstate,int proto)3136 gen_linktype(compiler_state_t *cstate, int proto)
3137 {
3138 struct block *b0, *b1, *b2;
3139 const char *description;
3140
3141 /* are we checking MPLS-encapsulated packets? */
3142 if (cstate->label_stack_depth > 0) {
3143 switch (proto) {
3144 case ETHERTYPE_IP:
3145 case PPP_IP:
3146 /* FIXME add other L3 proto IDs */
3147 return gen_mpls_linktype(cstate, Q_IP);
3148
3149 case ETHERTYPE_IPV6:
3150 case PPP_IPV6:
3151 /* FIXME add other L3 proto IDs */
3152 return gen_mpls_linktype(cstate, Q_IPV6);
3153
3154 default:
3155 bpf_error(cstate, "unsupported protocol over mpls");
3156 /*NOTREACHED*/
3157 }
3158 }
3159
3160 switch (cstate->linktype) {
3161
3162 case DLT_EN10MB:
3163 case DLT_NETANALYZER:
3164 case DLT_NETANALYZER_TRANSPARENT:
3165 /* Geneve has an EtherType regardless of whether there is an
3166 * L2 header. */
3167 if (!cstate->is_geneve)
3168 b0 = gen_prevlinkhdr_check(cstate);
3169 else
3170 b0 = NULL;
3171
3172 b1 = gen_ether_linktype(cstate, proto);
3173 if (b0 != NULL)
3174 gen_and(b0, b1);
3175 return b1;
3176 /*NOTREACHED*/
3177
3178 case DLT_C_HDLC:
3179 switch (proto) {
3180
3181 case LLCSAP_ISONS:
3182 proto = (proto << 8 | LLCSAP_ISONS);
3183 /* fall through */
3184
3185 default:
3186 return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)proto);
3187 /*NOTREACHED*/
3188 }
3189
3190 case DLT_IEEE802_11:
3191 case DLT_PRISM_HEADER:
3192 case DLT_IEEE802_11_RADIO_AVS:
3193 case DLT_IEEE802_11_RADIO:
3194 case DLT_PPI:
3195 /*
3196 * Check that we have a data frame.
3197 */
3198 b0 = gen_check_802_11_data_frame(cstate);
3199
3200 /*
3201 * Now check for the specified link-layer type.
3202 */
3203 b1 = gen_llc_linktype(cstate, proto);
3204 gen_and(b0, b1);
3205 return b1;
3206 /*NOTREACHED*/
3207
3208 case DLT_FDDI:
3209 /*
3210 * XXX - check for LLC frames.
3211 */
3212 return gen_llc_linktype(cstate, proto);
3213 /*NOTREACHED*/
3214
3215 case DLT_IEEE802:
3216 /*
3217 * XXX - check for LLC PDUs, as per IEEE 802.5.
3218 */
3219 return gen_llc_linktype(cstate, proto);
3220 /*NOTREACHED*/
3221
3222 case DLT_ATM_RFC1483:
3223 case DLT_ATM_CLIP:
3224 case DLT_IP_OVER_FC:
3225 return gen_llc_linktype(cstate, proto);
3226 /*NOTREACHED*/
3227
3228 case DLT_SUNATM:
3229 /*
3230 * Check for an LLC-encapsulated version of this protocol;
3231 * if we were checking for LANE, linktype would no longer
3232 * be DLT_SUNATM.
3233 *
3234 * Check for LLC encapsulation and then check the protocol.
3235 */
3236 b0 = gen_atmfield_code_internal(cstate, A_PROTOTYPE, PT_LLC, BPF_JEQ, 0);
3237 b1 = gen_llc_linktype(cstate, proto);
3238 gen_and(b0, b1);
3239 return b1;
3240 /*NOTREACHED*/
3241
3242 case DLT_LINUX_SLL:
3243 return gen_linux_sll_linktype(cstate, proto);
3244 /*NOTREACHED*/
3245
3246 case DLT_SLIP:
3247 case DLT_SLIP_BSDOS:
3248 case DLT_RAW:
3249 /*
3250 * These types don't provide any type field; packets
3251 * are always IPv4 or IPv6.
3252 *
3253 * XXX - for IPv4, check for a version number of 4, and,
3254 * for IPv6, check for a version number of 6?
3255 */
3256 switch (proto) {
3257
3258 case ETHERTYPE_IP:
3259 /* Check for a version number of 4. */
3260 return gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, 0x40, 0xF0);
3261
3262 case ETHERTYPE_IPV6:
3263 /* Check for a version number of 6. */
3264 return gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, 0x60, 0xF0);
3265
3266 default:
3267 return gen_false(cstate); /* always false */
3268 }
3269 /*NOTREACHED*/
3270
3271 case DLT_IPV4:
3272 /*
3273 * Raw IPv4, so no type field.
3274 */
3275 if (proto == ETHERTYPE_IP)
3276 return gen_true(cstate); /* always true */
3277
3278 /* Checking for something other than IPv4; always false */
3279 return gen_false(cstate);
3280 /*NOTREACHED*/
3281
3282 case DLT_IPV6:
3283 /*
3284 * Raw IPv6, so no type field.
3285 */
3286 if (proto == ETHERTYPE_IPV6)
3287 return gen_true(cstate); /* always true */
3288
3289 /* Checking for something other than IPv6; always false */
3290 return gen_false(cstate);
3291 /*NOTREACHED*/
3292
3293 case DLT_PPP:
3294 case DLT_PPP_PPPD:
3295 case DLT_PPP_SERIAL:
3296 case DLT_PPP_ETHER:
3297 /*
3298 * We use Ethernet protocol types inside libpcap;
3299 * map them to the corresponding PPP protocol types.
3300 */
3301 proto = ethertype_to_ppptype(proto);
3302 return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)proto);
3303 /*NOTREACHED*/
3304
3305 case DLT_PPP_BSDOS:
3306 /*
3307 * We use Ethernet protocol types inside libpcap;
3308 * map them to the corresponding PPP protocol types.
3309 */
3310 switch (proto) {
3311
3312 case ETHERTYPE_IP:
3313 /*
3314 * Also check for Van Jacobson-compressed IP.
3315 * XXX - do this for other forms of PPP?
3316 */
3317 b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, PPP_IP);
3318 b1 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, PPP_VJC);
3319 gen_or(b0, b1);
3320 b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, PPP_VJNC);
3321 gen_or(b1, b0);
3322 return b0;
3323
3324 default:
3325 proto = ethertype_to_ppptype(proto);
3326 return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H,
3327 (bpf_int32)proto);
3328 }
3329 /*NOTREACHED*/
3330
3331 case DLT_NULL:
3332 case DLT_LOOP:
3333 case DLT_ENC:
3334 switch (proto) {
3335
3336 case ETHERTYPE_IP:
3337 return (gen_loopback_linktype(cstate, AF_INET));
3338
3339 case ETHERTYPE_IPV6:
3340 /*
3341 * AF_ values may, unfortunately, be platform-
3342 * dependent; AF_INET isn't, because everybody
3343 * used 4.2BSD's value, but AF_INET6 is, because
3344 * 4.2BSD didn't have a value for it (given that
3345 * IPv6 didn't exist back in the early 1980's),
3346 * and they all picked their own values.
3347 *
3348 * This means that, if we're reading from a
3349 * savefile, we need to check for all the
3350 * possible values.
3351 *
3352 * If we're doing a live capture, we only need
3353 * to check for this platform's value; however,
3354 * Npcap uses 24, which isn't Windows's AF_INET6
3355 * value. (Given the multiple different values,
3356 * programs that read pcap files shouldn't be
3357 * checking for their platform's AF_INET6 value
3358 * anyway, they should check for all of the
3359 * possible values. and they might as well do
3360 * that even for live captures.)
3361 */
3362 if (cstate->bpf_pcap->rfile != NULL) {
3363 /*
3364 * Savefile - check for all three
3365 * possible IPv6 values.
3366 */
3367 b0 = gen_loopback_linktype(cstate, BSD_AFNUM_INET6_BSD);
3368 b1 = gen_loopback_linktype(cstate, BSD_AFNUM_INET6_FREEBSD);
3369 gen_or(b0, b1);
3370 b0 = gen_loopback_linktype(cstate, BSD_AFNUM_INET6_DARWIN);
3371 gen_or(b0, b1);
3372 return (b1);
3373 } else {
3374 /*
3375 * Live capture, so we only need to
3376 * check for the value used on this
3377 * platform.
3378 */
3379 #ifdef _WIN32
3380 /*
3381 * Npcap doesn't use Windows's AF_INET6,
3382 * as that collides with AF_IPX on
3383 * some BSDs (both have the value 23).
3384 * Instead, it uses 24.
3385 */
3386 return (gen_loopback_linktype(cstate, 24));
3387 #else /* _WIN32 */
3388 #ifdef AF_INET6
3389 return (gen_loopback_linktype(cstate, AF_INET6));
3390 #else /* AF_INET6 */
3391 /*
3392 * I guess this platform doesn't support
3393 * IPv6, so we just reject all packets.
3394 */
3395 return gen_false(cstate);
3396 #endif /* AF_INET6 */
3397 #endif /* _WIN32 */
3398 }
3399
3400 default:
3401 /*
3402 * Not a type on which we support filtering.
3403 * XXX - support those that have AF_ values
3404 * #defined on this platform, at least?
3405 */
3406 return gen_false(cstate);
3407 }
3408
3409 #ifdef HAVE_NET_PFVAR_H
3410 case DLT_PFLOG:
3411 /*
3412 * af field is host byte order in contrast to the rest of
3413 * the packet.
3414 */
3415 if (proto == ETHERTYPE_IP)
3416 return (gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, af),
3417 BPF_B, (bpf_int32)AF_INET));
3418 else if (proto == ETHERTYPE_IPV6)
3419 return (gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, af),
3420 BPF_B, (bpf_int32)AF_INET6));
3421 else
3422 return gen_false(cstate);
3423 /*NOTREACHED*/
3424 #endif /* HAVE_NET_PFVAR_H */
3425
3426 case DLT_ARCNET:
3427 case DLT_ARCNET_LINUX:
3428 /*
3429 * XXX should we check for first fragment if the protocol
3430 * uses PHDS?
3431 */
3432 switch (proto) {
3433
3434 default:
3435 return gen_false(cstate);
3436
3437 case ETHERTYPE_IPV6:
3438 return (gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
3439 (bpf_int32)ARCTYPE_INET6));
3440
3441 case ETHERTYPE_IP:
3442 b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
3443 (bpf_int32)ARCTYPE_IP);
3444 b1 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
3445 (bpf_int32)ARCTYPE_IP_OLD);
3446 gen_or(b0, b1);
3447 return (b1);
3448
3449 case ETHERTYPE_ARP:
3450 b0 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
3451 (bpf_int32)ARCTYPE_ARP);
3452 b1 = gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
3453 (bpf_int32)ARCTYPE_ARP_OLD);
3454 gen_or(b0, b1);
3455 return (b1);
3456
3457 case ETHERTYPE_REVARP:
3458 return (gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
3459 (bpf_int32)ARCTYPE_REVARP));
3460
3461 case ETHERTYPE_ATALK:
3462 return (gen_cmp(cstate, OR_LINKTYPE, 0, BPF_B,
3463 (bpf_int32)ARCTYPE_ATALK));
3464 }
3465 /*NOTREACHED*/
3466
3467 case DLT_LTALK:
3468 switch (proto) {
3469 case ETHERTYPE_ATALK:
3470 return gen_true(cstate);
3471 default:
3472 return gen_false(cstate);
3473 }
3474 /*NOTREACHED*/
3475
3476 case DLT_FRELAY:
3477 /*
3478 * XXX - assumes a 2-byte Frame Relay header with
3479 * DLCI and flags. What if the address is longer?
3480 */
3481 switch (proto) {
3482
3483 case ETHERTYPE_IP:
3484 /*
3485 * Check for the special NLPID for IP.
3486 */
3487 return gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, (0x03<<8) | 0xcc);
3488
3489 case ETHERTYPE_IPV6:
3490 /*
3491 * Check for the special NLPID for IPv6.
3492 */
3493 return gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, (0x03<<8) | 0x8e);
3494
3495 case LLCSAP_ISONS:
3496 /*
3497 * Check for several OSI protocols.
3498 *
3499 * Frame Relay packets typically have an OSI
3500 * NLPID at the beginning; we check for each
3501 * of them.
3502 *
3503 * What we check for is the NLPID and a frame
3504 * control field of UI, i.e. 0x03 followed
3505 * by the NLPID.
3506 */
3507 b0 = gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, (0x03<<8) | ISO8473_CLNP);
3508 b1 = gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, (0x03<<8) | ISO9542_ESIS);
3509 b2 = gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, (0x03<<8) | ISO10589_ISIS);
3510 gen_or(b1, b2);
3511 gen_or(b0, b2);
3512 return b2;
3513
3514 default:
3515 return gen_false(cstate);
3516 }
3517 /*NOTREACHED*/
3518
3519 case DLT_MFR:
3520 bpf_error(cstate, "Multi-link Frame Relay link-layer type filtering not implemented");
3521
3522 case DLT_JUNIPER_MFR:
3523 case DLT_JUNIPER_MLFR:
3524 case DLT_JUNIPER_MLPPP:
3525 case DLT_JUNIPER_ATM1:
3526 case DLT_JUNIPER_ATM2:
3527 case DLT_JUNIPER_PPPOE:
3528 case DLT_JUNIPER_PPPOE_ATM:
3529 case DLT_JUNIPER_GGSN:
3530 case DLT_JUNIPER_ES:
3531 case DLT_JUNIPER_MONITOR:
3532 case DLT_JUNIPER_SERVICES:
3533 case DLT_JUNIPER_ETHER:
3534 case DLT_JUNIPER_PPP:
3535 case DLT_JUNIPER_FRELAY:
3536 case DLT_JUNIPER_CHDLC:
3537 case DLT_JUNIPER_VP:
3538 case DLT_JUNIPER_ST:
3539 case DLT_JUNIPER_ISM:
3540 case DLT_JUNIPER_VS:
3541 case DLT_JUNIPER_SRX_E2E:
3542 case DLT_JUNIPER_FIBRECHANNEL:
3543 case DLT_JUNIPER_ATM_CEMIC:
3544
3545 /* just lets verify the magic number for now -
3546 * on ATM we may have up to 6 different encapsulations on the wire
3547 * and need a lot of heuristics to figure out that the payload
3548 * might be;
3549 *
3550 * FIXME encapsulation specific BPF_ filters
3551 */
3552 return gen_mcmp(cstate, OR_LINKHDR, 0, BPF_W, 0x4d474300, 0xffffff00); /* compare the magic number */
3553
3554 case DLT_BACNET_MS_TP:
3555 return gen_mcmp(cstate, OR_LINKHDR, 0, BPF_W, 0x55FF0000, 0xffff0000);
3556
3557 case DLT_IPNET:
3558 return gen_ipnet_linktype(cstate, proto);
3559
3560 case DLT_LINUX_IRDA:
3561 bpf_error(cstate, "IrDA link-layer type filtering not implemented");
3562
3563 case DLT_DOCSIS:
3564 bpf_error(cstate, "DOCSIS link-layer type filtering not implemented");
3565
3566 case DLT_MTP2:
3567 case DLT_MTP2_WITH_PHDR:
3568 bpf_error(cstate, "MTP2 link-layer type filtering not implemented");
3569
3570 case DLT_ERF:
3571 bpf_error(cstate, "ERF link-layer type filtering not implemented");
3572
3573 case DLT_PFSYNC:
3574 bpf_error(cstate, "PFSYNC link-layer type filtering not implemented");
3575
3576 case DLT_LINUX_LAPD:
3577 bpf_error(cstate, "LAPD link-layer type filtering not implemented");
3578
3579 case DLT_USB_FREEBSD:
3580 case DLT_USB_LINUX:
3581 case DLT_USB_LINUX_MMAPPED:
3582 case DLT_USBPCAP:
3583 bpf_error(cstate, "USB link-layer type filtering not implemented");
3584
3585 case DLT_BLUETOOTH_HCI_H4:
3586 case DLT_BLUETOOTH_HCI_H4_WITH_PHDR:
3587 bpf_error(cstate, "Bluetooth link-layer type filtering not implemented");
3588
3589 case DLT_CAN20B:
3590 case DLT_CAN_SOCKETCAN:
3591 bpf_error(cstate, "CAN link-layer type filtering not implemented");
3592
3593 case DLT_IEEE802_15_4:
3594 case DLT_IEEE802_15_4_LINUX:
3595 case DLT_IEEE802_15_4_NONASK_PHY:
3596 case DLT_IEEE802_15_4_NOFCS:
3597 bpf_error(cstate, "IEEE 802.15.4 link-layer type filtering not implemented");
3598
3599 case DLT_IEEE802_16_MAC_CPS_RADIO:
3600 bpf_error(cstate, "IEEE 802.16 link-layer type filtering not implemented");
3601
3602 case DLT_SITA:
3603 bpf_error(cstate, "SITA link-layer type filtering not implemented");
3604
3605 case DLT_RAIF1:
3606 bpf_error(cstate, "RAIF1 link-layer type filtering not implemented");
3607
3608 case DLT_IPMB_KONTRON:
3609 case DLT_IPMB_LINUX:
3610 bpf_error(cstate, "IPMB link-layer type filtering not implemented");
3611
3612 case DLT_AX25_KISS:
3613 bpf_error(cstate, "AX.25 link-layer type filtering not implemented");
3614
3615 case DLT_NFLOG:
3616 /* Using the fixed-size NFLOG header it is possible to tell only
3617 * the address family of the packet, other meaningful data is
3618 * either missing or behind TLVs.
3619 */
3620 bpf_error(cstate, "NFLOG link-layer type filtering not implemented");
3621
3622 default:
3623 /*
3624 * Does this link-layer header type have a field
3625 * indicating the type of the next protocol? If
3626 * so, off_linktype.constant_part will be the offset of that
3627 * field in the packet; if not, it will be OFFSET_NOT_SET.
3628 */
3629 if (cstate->off_linktype.constant_part != OFFSET_NOT_SET) {
3630 /*
3631 * Yes; assume it's an Ethernet type. (If
3632 * it's not, it needs to be handled specially
3633 * above.)
3634 */
3635 return gen_cmp(cstate, OR_LINKTYPE, 0, BPF_H, (bpf_int32)proto);
3636 /*NOTREACHED */
3637 } else {
3638 /*
3639 * No; report an error.
3640 */
3641 description = pcap_datalink_val_to_description_or_dlt(cstate->linktype);
3642 bpf_error(cstate, "%s link-layer type filtering not implemented",
3643 description);
3644 /*NOTREACHED */
3645 }
3646 }
3647 }
3648
3649 /*
3650 * Check for an LLC SNAP packet with a given organization code and
3651 * protocol type; we check the entire contents of the 802.2 LLC and
3652 * snap headers, checking for DSAP and SSAP of SNAP and a control
3653 * field of 0x03 in the LLC header, and for the specified organization
3654 * code and protocol type in the SNAP header.
3655 */
3656 static struct block *
gen_snap(compiler_state_t * cstate,bpf_u_int32 orgcode,bpf_u_int32 ptype)3657 gen_snap(compiler_state_t *cstate, bpf_u_int32 orgcode, bpf_u_int32 ptype)
3658 {
3659 u_char snapblock[8];
3660
3661 snapblock[0] = LLCSAP_SNAP; /* DSAP = SNAP */
3662 snapblock[1] = LLCSAP_SNAP; /* SSAP = SNAP */
3663 snapblock[2] = 0x03; /* control = UI */
3664 snapblock[3] = (u_char)(orgcode >> 16); /* upper 8 bits of organization code */
3665 snapblock[4] = (u_char)(orgcode >> 8); /* middle 8 bits of organization code */
3666 snapblock[5] = (u_char)(orgcode >> 0); /* lower 8 bits of organization code */
3667 snapblock[6] = (u_char)(ptype >> 8); /* upper 8 bits of protocol type */
3668 snapblock[7] = (u_char)(ptype >> 0); /* lower 8 bits of protocol type */
3669 return gen_bcmp(cstate, OR_LLC, 0, 8, snapblock);
3670 }
3671
3672 /*
3673 * Generate code to match frames with an LLC header.
3674 */
3675 static struct block *
gen_llc_internal(compiler_state_t * cstate)3676 gen_llc_internal(compiler_state_t *cstate)
3677 {
3678 struct block *b0, *b1;
3679
3680 switch (cstate->linktype) {
3681
3682 case DLT_EN10MB:
3683 /*
3684 * We check for an Ethernet type field less than
3685 * 1500, which means it's an 802.3 length field.
3686 */
3687 b0 = gen_cmp_gt(cstate, OR_LINKTYPE, 0, BPF_H, ETHERMTU);
3688 gen_not(b0);
3689
3690 /*
3691 * Now check for the purported DSAP and SSAP not being
3692 * 0xFF, to rule out NetWare-over-802.3.
3693 */
3694 b1 = gen_cmp(cstate, OR_LLC, 0, BPF_H, (bpf_int32)0xFFFF);
3695 gen_not(b1);
3696 gen_and(b0, b1);
3697 return b1;
3698
3699 case DLT_SUNATM:
3700 /*
3701 * We check for LLC traffic.
3702 */
3703 b0 = gen_atmtype_llc(cstate);
3704 return b0;
3705
3706 case DLT_IEEE802: /* Token Ring */
3707 /*
3708 * XXX - check for LLC frames.
3709 */
3710 return gen_true(cstate);
3711
3712 case DLT_FDDI:
3713 /*
3714 * XXX - check for LLC frames.
3715 */
3716 return gen_true(cstate);
3717
3718 case DLT_ATM_RFC1483:
3719 /*
3720 * For LLC encapsulation, these are defined to have an
3721 * 802.2 LLC header.
3722 *
3723 * For VC encapsulation, they don't, but there's no
3724 * way to check for that; the protocol used on the VC
3725 * is negotiated out of band.
3726 */
3727 return gen_true(cstate);
3728
3729 case DLT_IEEE802_11:
3730 case DLT_PRISM_HEADER:
3731 case DLT_IEEE802_11_RADIO:
3732 case DLT_IEEE802_11_RADIO_AVS:
3733 case DLT_PPI:
3734 /*
3735 * Check that we have a data frame.
3736 */
3737 b0 = gen_check_802_11_data_frame(cstate);
3738 return b0;
3739
3740 default:
3741 bpf_error(cstate, "'llc' not supported for %s",
3742 pcap_datalink_val_to_description_or_dlt(cstate->linktype));
3743 /*NOTREACHED*/
3744 }
3745 }
3746
3747 struct block *
gen_llc(compiler_state_t * cstate)3748 gen_llc(compiler_state_t *cstate)
3749 {
3750 /*
3751 * Catch errors reported by us and routines below us, and return NULL
3752 * on an error.
3753 */
3754 if (setjmp(cstate->top_ctx))
3755 return (NULL);
3756
3757 return gen_llc_internal(cstate);
3758 }
3759
3760 struct block *
gen_llc_i(compiler_state_t * cstate)3761 gen_llc_i(compiler_state_t *cstate)
3762 {
3763 struct block *b0, *b1;
3764 struct slist *s;
3765
3766 /*
3767 * Catch errors reported by us and routines below us, and return NULL
3768 * on an error.
3769 */
3770 if (setjmp(cstate->top_ctx))
3771 return (NULL);
3772
3773 /*
3774 * Check whether this is an LLC frame.
3775 */
3776 b0 = gen_llc_internal(cstate);
3777
3778 /*
3779 * Load the control byte and test the low-order bit; it must
3780 * be clear for I frames.
3781 */
3782 s = gen_load_a(cstate, OR_LLC, 2, BPF_B);
3783 b1 = new_block(cstate, JMP(BPF_JSET));
3784 b1->s.k = 0x01;
3785 b1->stmts = s;
3786 gen_not(b1);
3787 gen_and(b0, b1);
3788 return b1;
3789 }
3790
3791 struct block *
gen_llc_s(compiler_state_t * cstate)3792 gen_llc_s(compiler_state_t *cstate)
3793 {
3794 struct block *b0, *b1;
3795
3796 /*
3797 * Catch errors reported by us and routines below us, and return NULL
3798 * on an error.
3799 */
3800 if (setjmp(cstate->top_ctx))
3801 return (NULL);
3802
3803 /*
3804 * Check whether this is an LLC frame.
3805 */
3806 b0 = gen_llc_internal(cstate);
3807
3808 /*
3809 * Now compare the low-order 2 bit of the control byte against
3810 * the appropriate value for S frames.
3811 */
3812 b1 = gen_mcmp(cstate, OR_LLC, 2, BPF_B, LLC_S_FMT, 0x03);
3813 gen_and(b0, b1);
3814 return b1;
3815 }
3816
3817 struct block *
gen_llc_u(compiler_state_t * cstate)3818 gen_llc_u(compiler_state_t *cstate)
3819 {
3820 struct block *b0, *b1;
3821
3822 /*
3823 * Catch errors reported by us and routines below us, and return NULL
3824 * on an error.
3825 */
3826 if (setjmp(cstate->top_ctx))
3827 return (NULL);
3828
3829 /*
3830 * Check whether this is an LLC frame.
3831 */
3832 b0 = gen_llc_internal(cstate);
3833
3834 /*
3835 * Now compare the low-order 2 bit of the control byte against
3836 * the appropriate value for U frames.
3837 */
3838 b1 = gen_mcmp(cstate, OR_LLC, 2, BPF_B, LLC_U_FMT, 0x03);
3839 gen_and(b0, b1);
3840 return b1;
3841 }
3842
3843 struct block *
gen_llc_s_subtype(compiler_state_t * cstate,bpf_u_int32 subtype)3844 gen_llc_s_subtype(compiler_state_t *cstate, bpf_u_int32 subtype)
3845 {
3846 struct block *b0, *b1;
3847
3848 /*
3849 * Catch errors reported by us and routines below us, and return NULL
3850 * on an error.
3851 */
3852 if (setjmp(cstate->top_ctx))
3853 return (NULL);
3854
3855 /*
3856 * Check whether this is an LLC frame.
3857 */
3858 b0 = gen_llc_internal(cstate);
3859
3860 /*
3861 * Now check for an S frame with the appropriate type.
3862 */
3863 b1 = gen_mcmp(cstate, OR_LLC, 2, BPF_B, subtype, LLC_S_CMD_MASK);
3864 gen_and(b0, b1);
3865 return b1;
3866 }
3867
3868 struct block *
gen_llc_u_subtype(compiler_state_t * cstate,bpf_u_int32 subtype)3869 gen_llc_u_subtype(compiler_state_t *cstate, bpf_u_int32 subtype)
3870 {
3871 struct block *b0, *b1;
3872
3873 /*
3874 * Catch errors reported by us and routines below us, and return NULL
3875 * on an error.
3876 */
3877 if (setjmp(cstate->top_ctx))
3878 return (NULL);
3879
3880 /*
3881 * Check whether this is an LLC frame.
3882 */
3883 b0 = gen_llc_internal(cstate);
3884
3885 /*
3886 * Now check for a U frame with the appropriate type.
3887 */
3888 b1 = gen_mcmp(cstate, OR_LLC, 2, BPF_B, subtype, LLC_U_CMD_MASK);
3889 gen_and(b0, b1);
3890 return b1;
3891 }
3892
3893 /*
3894 * Generate code to match a particular packet type, for link-layer types
3895 * using 802.2 LLC headers.
3896 *
3897 * This is *NOT* used for Ethernet; "gen_ether_linktype()" is used
3898 * for that - it handles the D/I/X Ethernet vs. 802.3+802.2 issues.
3899 *
3900 * "proto" is an Ethernet type value, if > ETHERMTU, or an LLC SAP
3901 * value, if <= ETHERMTU. We use that to determine whether to
3902 * match the DSAP or both DSAP and LSAP or to check the OUI and
3903 * protocol ID in a SNAP header.
3904 */
3905 static struct block *
gen_llc_linktype(compiler_state_t * cstate,int proto)3906 gen_llc_linktype(compiler_state_t *cstate, int proto)
3907 {
3908 /*
3909 * XXX - handle token-ring variable-length header.
3910 */
3911 switch (proto) {
3912
3913 case LLCSAP_IP:
3914 case LLCSAP_ISONS:
3915 case LLCSAP_NETBEUI:
3916 /*
3917 * XXX - should we check both the DSAP and the
3918 * SSAP, like this, or should we check just the
3919 * DSAP, as we do for other SAP values?
3920 */
3921 return gen_cmp(cstate, OR_LLC, 0, BPF_H, (bpf_u_int32)
3922 ((proto << 8) | proto));
3923
3924 case LLCSAP_IPX:
3925 /*
3926 * XXX - are there ever SNAP frames for IPX on
3927 * non-Ethernet 802.x networks?
3928 */
3929 return gen_cmp(cstate, OR_LLC, 0, BPF_B,
3930 (bpf_int32)LLCSAP_IPX);
3931
3932 case ETHERTYPE_ATALK:
3933 /*
3934 * 802.2-encapsulated ETHERTYPE_ATALK packets are
3935 * SNAP packets with an organization code of
3936 * 0x080007 (Apple, for Appletalk) and a protocol
3937 * type of ETHERTYPE_ATALK (Appletalk).
3938 *
3939 * XXX - check for an organization code of
3940 * encapsulated Ethernet as well?
3941 */
3942 return gen_snap(cstate, 0x080007, ETHERTYPE_ATALK);
3943
3944 default:
3945 /*
3946 * XXX - we don't have to check for IPX 802.3
3947 * here, but should we check for the IPX Ethertype?
3948 */
3949 if (proto <= ETHERMTU) {
3950 /*
3951 * This is an LLC SAP value, so check
3952 * the DSAP.
3953 */
3954 return gen_cmp(cstate, OR_LLC, 0, BPF_B, (bpf_int32)proto);
3955 } else {
3956 /*
3957 * This is an Ethernet type; we assume that it's
3958 * unlikely that it'll appear in the right place
3959 * at random, and therefore check only the
3960 * location that would hold the Ethernet type
3961 * in a SNAP frame with an organization code of
3962 * 0x000000 (encapsulated Ethernet).
3963 *
3964 * XXX - if we were to check for the SNAP DSAP and
3965 * LSAP, as per XXX, and were also to check for an
3966 * organization code of 0x000000 (encapsulated
3967 * Ethernet), we'd do
3968 *
3969 * return gen_snap(cstate, 0x000000, proto);
3970 *
3971 * here; for now, we don't, as per the above.
3972 * I don't know whether it's worth the extra CPU
3973 * time to do the right check or not.
3974 */
3975 return gen_cmp(cstate, OR_LLC, 6, BPF_H, (bpf_int32)proto);
3976 }
3977 }
3978 }
3979
3980 static struct block *
gen_hostop(compiler_state_t * cstate,bpf_u_int32 addr,bpf_u_int32 mask,int dir,int proto,u_int src_off,u_int dst_off)3981 gen_hostop(compiler_state_t *cstate, bpf_u_int32 addr, bpf_u_int32 mask,
3982 int dir, int proto, u_int src_off, u_int dst_off)
3983 {
3984 struct block *b0, *b1;
3985 u_int offset;
3986
3987 switch (dir) {
3988
3989 case Q_SRC:
3990 offset = src_off;
3991 break;
3992
3993 case Q_DST:
3994 offset = dst_off;
3995 break;
3996
3997 case Q_AND:
3998 b0 = gen_hostop(cstate, addr, mask, Q_SRC, proto, src_off, dst_off);
3999 b1 = gen_hostop(cstate, addr, mask, Q_DST, proto, src_off, dst_off);
4000 gen_and(b0, b1);
4001 return b1;
4002
4003 case Q_DEFAULT:
4004 case Q_OR:
4005 b0 = gen_hostop(cstate, addr, mask, Q_SRC, proto, src_off, dst_off);
4006 b1 = gen_hostop(cstate, addr, mask, Q_DST, proto, src_off, dst_off);
4007 gen_or(b0, b1);
4008 return b1;
4009
4010 case Q_ADDR1:
4011 bpf_error(cstate, "'addr1' and 'address1' are not valid qualifiers for addresses other than 802.11 MAC addresses");
4012 /*NOTREACHED*/
4013
4014 case Q_ADDR2:
4015 bpf_error(cstate, "'addr2' and 'address2' are not valid qualifiers for addresses other than 802.11 MAC addresses");
4016 /*NOTREACHED*/
4017
4018 case Q_ADDR3:
4019 bpf_error(cstate, "'addr3' and 'address3' are not valid qualifiers for addresses other than 802.11 MAC addresses");
4020 /*NOTREACHED*/
4021
4022 case Q_ADDR4:
4023 bpf_error(cstate, "'addr4' and 'address4' are not valid qualifiers for addresses other than 802.11 MAC addresses");
4024 /*NOTREACHED*/
4025
4026 case Q_RA:
4027 bpf_error(cstate, "'ra' is not a valid qualifier for addresses other than 802.11 MAC addresses");
4028 /*NOTREACHED*/
4029
4030 case Q_TA:
4031 bpf_error(cstate, "'ta' is not a valid qualifier for addresses other than 802.11 MAC addresses");
4032 /*NOTREACHED*/
4033
4034 default:
4035 abort();
4036 /*NOTREACHED*/
4037 }
4038 b0 = gen_linktype(cstate, proto);
4039 b1 = gen_mcmp(cstate, OR_LINKPL, offset, BPF_W, (bpf_int32)addr, mask);
4040 gen_and(b0, b1);
4041 return b1;
4042 }
4043
4044 #ifdef INET6
4045 static struct block *
gen_hostop6(compiler_state_t * cstate,struct in6_addr * addr,struct in6_addr * mask,int dir,int proto,u_int src_off,u_int dst_off)4046 gen_hostop6(compiler_state_t *cstate, struct in6_addr *addr,
4047 struct in6_addr *mask, int dir, int proto, u_int src_off, u_int dst_off)
4048 {
4049 struct block *b0, *b1;
4050 u_int offset;
4051 uint32_t *a, *m;
4052
4053 switch (dir) {
4054
4055 case Q_SRC:
4056 offset = src_off;
4057 break;
4058
4059 case Q_DST:
4060 offset = dst_off;
4061 break;
4062
4063 case Q_AND:
4064 b0 = gen_hostop6(cstate, addr, mask, Q_SRC, proto, src_off, dst_off);
4065 b1 = gen_hostop6(cstate, addr, mask, Q_DST, proto, src_off, dst_off);
4066 gen_and(b0, b1);
4067 return b1;
4068
4069 case Q_DEFAULT:
4070 case Q_OR:
4071 b0 = gen_hostop6(cstate, addr, mask, Q_SRC, proto, src_off, dst_off);
4072 b1 = gen_hostop6(cstate, addr, mask, Q_DST, proto, src_off, dst_off);
4073 gen_or(b0, b1);
4074 return b1;
4075
4076 case Q_ADDR1:
4077 bpf_error(cstate, "'addr1' and 'address1' are not valid qualifiers for addresses other than 802.11 MAC addresses");
4078 /*NOTREACHED*/
4079
4080 case Q_ADDR2:
4081 bpf_error(cstate, "'addr2' and 'address2' are not valid qualifiers for addresses other than 802.11 MAC addresses");
4082 /*NOTREACHED*/
4083
4084 case Q_ADDR3:
4085 bpf_error(cstate, "'addr3' and 'address3' are not valid qualifiers for addresses other than 802.11 MAC addresses");
4086 /*NOTREACHED*/
4087
4088 case Q_ADDR4:
4089 bpf_error(cstate, "'addr4' and 'address4' are not valid qualifiers for addresses other than 802.11 MAC addresses");
4090 /*NOTREACHED*/
4091
4092 case Q_RA:
4093 bpf_error(cstate, "'ra' is not a valid qualifier for addresses other than 802.11 MAC addresses");
4094 /*NOTREACHED*/
4095
4096 case Q_TA:
4097 bpf_error(cstate, "'ta' is not a valid qualifier for addresses other than 802.11 MAC addresses");
4098 /*NOTREACHED*/
4099
4100 default:
4101 abort();
4102 /*NOTREACHED*/
4103 }
4104 /* this order is important */
4105 a = (uint32_t *)addr;
4106 m = (uint32_t *)mask;
4107 b1 = gen_mcmp(cstate, OR_LINKPL, offset + 12, BPF_W, ntohl(a[3]), ntohl(m[3]));
4108 b0 = gen_mcmp(cstate, OR_LINKPL, offset + 8, BPF_W, ntohl(a[2]), ntohl(m[2]));
4109 gen_and(b0, b1);
4110 b0 = gen_mcmp(cstate, OR_LINKPL, offset + 4, BPF_W, ntohl(a[1]), ntohl(m[1]));
4111 gen_and(b0, b1);
4112 b0 = gen_mcmp(cstate, OR_LINKPL, offset + 0, BPF_W, ntohl(a[0]), ntohl(m[0]));
4113 gen_and(b0, b1);
4114 b0 = gen_linktype(cstate, proto);
4115 gen_and(b0, b1);
4116 return b1;
4117 }
4118 #endif
4119
4120 static struct block *
gen_ehostop(compiler_state_t * cstate,const u_char * eaddr,int dir)4121 gen_ehostop(compiler_state_t *cstate, const u_char *eaddr, int dir)
4122 {
4123 register struct block *b0, *b1;
4124
4125 switch (dir) {
4126 case Q_SRC:
4127 return gen_bcmp(cstate, OR_LINKHDR, 6, 6, eaddr);
4128
4129 case Q_DST:
4130 return gen_bcmp(cstate, OR_LINKHDR, 0, 6, eaddr);
4131
4132 case Q_AND:
4133 b0 = gen_ehostop(cstate, eaddr, Q_SRC);
4134 b1 = gen_ehostop(cstate, eaddr, Q_DST);
4135 gen_and(b0, b1);
4136 return b1;
4137
4138 case Q_DEFAULT:
4139 case Q_OR:
4140 b0 = gen_ehostop(cstate, eaddr, Q_SRC);
4141 b1 = gen_ehostop(cstate, eaddr, Q_DST);
4142 gen_or(b0, b1);
4143 return b1;
4144
4145 case Q_ADDR1:
4146 bpf_error(cstate, "'addr1' and 'address1' are only supported on 802.11 with 802.11 headers");
4147 /*NOTREACHED*/
4148
4149 case Q_ADDR2:
4150 bpf_error(cstate, "'addr2' and 'address2' are only supported on 802.11 with 802.11 headers");
4151 /*NOTREACHED*/
4152
4153 case Q_ADDR3:
4154 bpf_error(cstate, "'addr3' and 'address3' are only supported on 802.11 with 802.11 headers");
4155 /*NOTREACHED*/
4156
4157 case Q_ADDR4:
4158 bpf_error(cstate, "'addr4' and 'address4' are only supported on 802.11 with 802.11 headers");
4159 /*NOTREACHED*/
4160
4161 case Q_RA:
4162 bpf_error(cstate, "'ra' is only supported on 802.11 with 802.11 headers");
4163 /*NOTREACHED*/
4164
4165 case Q_TA:
4166 bpf_error(cstate, "'ta' is only supported on 802.11 with 802.11 headers");
4167 /*NOTREACHED*/
4168 }
4169 abort();
4170 /*NOTREACHED*/
4171 }
4172
4173 /*
4174 * Like gen_ehostop, but for DLT_FDDI
4175 */
4176 static struct block *
gen_fhostop(compiler_state_t * cstate,const u_char * eaddr,int dir)4177 gen_fhostop(compiler_state_t *cstate, const u_char *eaddr, int dir)
4178 {
4179 struct block *b0, *b1;
4180
4181 switch (dir) {
4182 case Q_SRC:
4183 return gen_bcmp(cstate, OR_LINKHDR, 6 + 1 + cstate->pcap_fddipad, 6, eaddr);
4184
4185 case Q_DST:
4186 return gen_bcmp(cstate, OR_LINKHDR, 0 + 1 + cstate->pcap_fddipad, 6, eaddr);
4187
4188 case Q_AND:
4189 b0 = gen_fhostop(cstate, eaddr, Q_SRC);
4190 b1 = gen_fhostop(cstate, eaddr, Q_DST);
4191 gen_and(b0, b1);
4192 return b1;
4193
4194 case Q_DEFAULT:
4195 case Q_OR:
4196 b0 = gen_fhostop(cstate, eaddr, Q_SRC);
4197 b1 = gen_fhostop(cstate, eaddr, Q_DST);
4198 gen_or(b0, b1);
4199 return b1;
4200
4201 case Q_ADDR1:
4202 bpf_error(cstate, "'addr1' and 'address1' are only supported on 802.11");
4203 /*NOTREACHED*/
4204
4205 case Q_ADDR2:
4206 bpf_error(cstate, "'addr2' and 'address2' are only supported on 802.11");
4207 /*NOTREACHED*/
4208
4209 case Q_ADDR3:
4210 bpf_error(cstate, "'addr3' and 'address3' are only supported on 802.11");
4211 /*NOTREACHED*/
4212
4213 case Q_ADDR4:
4214 bpf_error(cstate, "'addr4' and 'address4' are only supported on 802.11");
4215 /*NOTREACHED*/
4216
4217 case Q_RA:
4218 bpf_error(cstate, "'ra' is only supported on 802.11");
4219 /*NOTREACHED*/
4220
4221 case Q_TA:
4222 bpf_error(cstate, "'ta' is only supported on 802.11");
4223 /*NOTREACHED*/
4224 }
4225 abort();
4226 /*NOTREACHED*/
4227 }
4228
4229 /*
4230 * Like gen_ehostop, but for DLT_IEEE802 (Token Ring)
4231 */
4232 static struct block *
gen_thostop(compiler_state_t * cstate,const u_char * eaddr,int dir)4233 gen_thostop(compiler_state_t *cstate, const u_char *eaddr, int dir)
4234 {
4235 register struct block *b0, *b1;
4236
4237 switch (dir) {
4238 case Q_SRC:
4239 return gen_bcmp(cstate, OR_LINKHDR, 8, 6, eaddr);
4240
4241 case Q_DST:
4242 return gen_bcmp(cstate, OR_LINKHDR, 2, 6, eaddr);
4243
4244 case Q_AND:
4245 b0 = gen_thostop(cstate, eaddr, Q_SRC);
4246 b1 = gen_thostop(cstate, eaddr, Q_DST);
4247 gen_and(b0, b1);
4248 return b1;
4249
4250 case Q_DEFAULT:
4251 case Q_OR:
4252 b0 = gen_thostop(cstate, eaddr, Q_SRC);
4253 b1 = gen_thostop(cstate, eaddr, Q_DST);
4254 gen_or(b0, b1);
4255 return b1;
4256
4257 case Q_ADDR1:
4258 bpf_error(cstate, "'addr1' and 'address1' are only supported on 802.11");
4259 /*NOTREACHED*/
4260
4261 case Q_ADDR2:
4262 bpf_error(cstate, "'addr2' and 'address2' are only supported on 802.11");
4263 /*NOTREACHED*/
4264
4265 case Q_ADDR3:
4266 bpf_error(cstate, "'addr3' and 'address3' are only supported on 802.11");
4267 /*NOTREACHED*/
4268
4269 case Q_ADDR4:
4270 bpf_error(cstate, "'addr4' and 'address4' are only supported on 802.11");
4271 /*NOTREACHED*/
4272
4273 case Q_RA:
4274 bpf_error(cstate, "'ra' is only supported on 802.11");
4275 /*NOTREACHED*/
4276
4277 case Q_TA:
4278 bpf_error(cstate, "'ta' is only supported on 802.11");
4279 /*NOTREACHED*/
4280 }
4281 abort();
4282 /*NOTREACHED*/
4283 }
4284
4285 /*
4286 * Like gen_ehostop, but for DLT_IEEE802_11 (802.11 wireless LAN) and
4287 * various 802.11 + radio headers.
4288 */
4289 static struct block *
gen_wlanhostop(compiler_state_t * cstate,const u_char * eaddr,int dir)4290 gen_wlanhostop(compiler_state_t *cstate, const u_char *eaddr, int dir)
4291 {
4292 register struct block *b0, *b1, *b2;
4293 register struct slist *s;
4294
4295 #ifdef ENABLE_WLAN_FILTERING_PATCH
4296 /*
4297 * TODO GV 20070613
4298 * We need to disable the optimizer because the optimizer is buggy
4299 * and wipes out some LD instructions generated by the below
4300 * code to validate the Frame Control bits
4301 */
4302 cstate->no_optimize = 1;
4303 #endif /* ENABLE_WLAN_FILTERING_PATCH */
4304
4305 switch (dir) {
4306 case Q_SRC:
4307 /*
4308 * Oh, yuk.
4309 *
4310 * For control frames, there is no SA.
4311 *
4312 * For management frames, SA is at an
4313 * offset of 10 from the beginning of
4314 * the packet.
4315 *
4316 * For data frames, SA is at an offset
4317 * of 10 from the beginning of the packet
4318 * if From DS is clear, at an offset of
4319 * 16 from the beginning of the packet
4320 * if From DS is set and To DS is clear,
4321 * and an offset of 24 from the beginning
4322 * of the packet if From DS is set and To DS
4323 * is set.
4324 */
4325
4326 /*
4327 * Generate the tests to be done for data frames
4328 * with From DS set.
4329 *
4330 * First, check for To DS set, i.e. check "link[1] & 0x01".
4331 */
4332 s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
4333 b1 = new_block(cstate, JMP(BPF_JSET));
4334 b1->s.k = 0x01; /* To DS */
4335 b1->stmts = s;
4336
4337 /*
4338 * If To DS is set, the SA is at 24.
4339 */
4340 b0 = gen_bcmp(cstate, OR_LINKHDR, 24, 6, eaddr);
4341 gen_and(b1, b0);
4342
4343 /*
4344 * Now, check for To DS not set, i.e. check
4345 * "!(link[1] & 0x01)".
4346 */
4347 s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
4348 b2 = new_block(cstate, JMP(BPF_JSET));
4349 b2->s.k = 0x01; /* To DS */
4350 b2->stmts = s;
4351 gen_not(b2);
4352
4353 /*
4354 * If To DS is not set, the SA is at 16.
4355 */
4356 b1 = gen_bcmp(cstate, OR_LINKHDR, 16, 6, eaddr);
4357 gen_and(b2, b1);
4358
4359 /*
4360 * Now OR together the last two checks. That gives
4361 * the complete set of checks for data frames with
4362 * From DS set.
4363 */
4364 gen_or(b1, b0);
4365
4366 /*
4367 * Now check for From DS being set, and AND that with
4368 * the ORed-together checks.
4369 */
4370 s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
4371 b1 = new_block(cstate, JMP(BPF_JSET));
4372 b1->s.k = 0x02; /* From DS */
4373 b1->stmts = s;
4374 gen_and(b1, b0);
4375
4376 /*
4377 * Now check for data frames with From DS not set.
4378 */
4379 s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
4380 b2 = new_block(cstate, JMP(BPF_JSET));
4381 b2->s.k = 0x02; /* From DS */
4382 b2->stmts = s;
4383 gen_not(b2);
4384
4385 /*
4386 * If From DS isn't set, the SA is at 10.
4387 */
4388 b1 = gen_bcmp(cstate, OR_LINKHDR, 10, 6, eaddr);
4389 gen_and(b2, b1);
4390
4391 /*
4392 * Now OR together the checks for data frames with
4393 * From DS not set and for data frames with From DS
4394 * set; that gives the checks done for data frames.
4395 */
4396 gen_or(b1, b0);
4397
4398 /*
4399 * Now check for a data frame.
4400 * I.e, check "link[0] & 0x08".
4401 */
4402 s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
4403 b1 = new_block(cstate, JMP(BPF_JSET));
4404 b1->s.k = 0x08;
4405 b1->stmts = s;
4406
4407 /*
4408 * AND that with the checks done for data frames.
4409 */
4410 gen_and(b1, b0);
4411
4412 /*
4413 * If the high-order bit of the type value is 0, this
4414 * is a management frame.
4415 * I.e, check "!(link[0] & 0x08)".
4416 */
4417 s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
4418 b2 = new_block(cstate, JMP(BPF_JSET));
4419 b2->s.k = 0x08;
4420 b2->stmts = s;
4421 gen_not(b2);
4422
4423 /*
4424 * For management frames, the SA is at 10.
4425 */
4426 b1 = gen_bcmp(cstate, OR_LINKHDR, 10, 6, eaddr);
4427 gen_and(b2, b1);
4428
4429 /*
4430 * OR that with the checks done for data frames.
4431 * That gives the checks done for management and
4432 * data frames.
4433 */
4434 gen_or(b1, b0);
4435
4436 /*
4437 * If the low-order bit of the type value is 1,
4438 * this is either a control frame or a frame
4439 * with a reserved type, and thus not a
4440 * frame with an SA.
4441 *
4442 * I.e., check "!(link[0] & 0x04)".
4443 */
4444 s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
4445 b1 = new_block(cstate, JMP(BPF_JSET));
4446 b1->s.k = 0x04;
4447 b1->stmts = s;
4448 gen_not(b1);
4449
4450 /*
4451 * AND that with the checks for data and management
4452 * frames.
4453 */
4454 gen_and(b1, b0);
4455 return b0;
4456
4457 case Q_DST:
4458 /*
4459 * Oh, yuk.
4460 *
4461 * For control frames, there is no DA.
4462 *
4463 * For management frames, DA is at an
4464 * offset of 4 from the beginning of
4465 * the packet.
4466 *
4467 * For data frames, DA is at an offset
4468 * of 4 from the beginning of the packet
4469 * if To DS is clear and at an offset of
4470 * 16 from the beginning of the packet
4471 * if To DS is set.
4472 */
4473
4474 /*
4475 * Generate the tests to be done for data frames.
4476 *
4477 * First, check for To DS set, i.e. "link[1] & 0x01".
4478 */
4479 s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
4480 b1 = new_block(cstate, JMP(BPF_JSET));
4481 b1->s.k = 0x01; /* To DS */
4482 b1->stmts = s;
4483
4484 /*
4485 * If To DS is set, the DA is at 16.
4486 */
4487 b0 = gen_bcmp(cstate, OR_LINKHDR, 16, 6, eaddr);
4488 gen_and(b1, b0);
4489
4490 /*
4491 * Now, check for To DS not set, i.e. check
4492 * "!(link[1] & 0x01)".
4493 */
4494 s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
4495 b2 = new_block(cstate, JMP(BPF_JSET));
4496 b2->s.k = 0x01; /* To DS */
4497 b2->stmts = s;
4498 gen_not(b2);
4499
4500 /*
4501 * If To DS is not set, the DA is at 4.
4502 */
4503 b1 = gen_bcmp(cstate, OR_LINKHDR, 4, 6, eaddr);
4504 gen_and(b2, b1);
4505
4506 /*
4507 * Now OR together the last two checks. That gives
4508 * the complete set of checks for data frames.
4509 */
4510 gen_or(b1, b0);
4511
4512 /*
4513 * Now check for a data frame.
4514 * I.e, check "link[0] & 0x08".
4515 */
4516 s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
4517 b1 = new_block(cstate, JMP(BPF_JSET));
4518 b1->s.k = 0x08;
4519 b1->stmts = s;
4520
4521 /*
4522 * AND that with the checks done for data frames.
4523 */
4524 gen_and(b1, b0);
4525
4526 /*
4527 * If the high-order bit of the type value is 0, this
4528 * is a management frame.
4529 * I.e, check "!(link[0] & 0x08)".
4530 */
4531 s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
4532 b2 = new_block(cstate, JMP(BPF_JSET));
4533 b2->s.k = 0x08;
4534 b2->stmts = s;
4535 gen_not(b2);
4536
4537 /*
4538 * For management frames, the DA is at 4.
4539 */
4540 b1 = gen_bcmp(cstate, OR_LINKHDR, 4, 6, eaddr);
4541 gen_and(b2, b1);
4542
4543 /*
4544 * OR that with the checks done for data frames.
4545 * That gives the checks done for management and
4546 * data frames.
4547 */
4548 gen_or(b1, b0);
4549
4550 /*
4551 * If the low-order bit of the type value is 1,
4552 * this is either a control frame or a frame
4553 * with a reserved type, and thus not a
4554 * frame with an SA.
4555 *
4556 * I.e., check "!(link[0] & 0x04)".
4557 */
4558 s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
4559 b1 = new_block(cstate, JMP(BPF_JSET));
4560 b1->s.k = 0x04;
4561 b1->stmts = s;
4562 gen_not(b1);
4563
4564 /*
4565 * AND that with the checks for data and management
4566 * frames.
4567 */
4568 gen_and(b1, b0);
4569 return b0;
4570
4571 case Q_AND:
4572 b0 = gen_wlanhostop(cstate, eaddr, Q_SRC);
4573 b1 = gen_wlanhostop(cstate, eaddr, Q_DST);
4574 gen_and(b0, b1);
4575 return b1;
4576
4577 case Q_DEFAULT:
4578 case Q_OR:
4579 b0 = gen_wlanhostop(cstate, eaddr, Q_SRC);
4580 b1 = gen_wlanhostop(cstate, eaddr, Q_DST);
4581 gen_or(b0, b1);
4582 return b1;
4583
4584 /*
4585 * XXX - add BSSID keyword?
4586 */
4587 case Q_ADDR1:
4588 return (gen_bcmp(cstate, OR_LINKHDR, 4, 6, eaddr));
4589
4590 case Q_ADDR2:
4591 /*
4592 * Not present in CTS or ACK control frames.
4593 */
4594 b0 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_TYPE_CTL,
4595 IEEE80211_FC0_TYPE_MASK);
4596 gen_not(b0);
4597 b1 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_SUBTYPE_CTS,
4598 IEEE80211_FC0_SUBTYPE_MASK);
4599 gen_not(b1);
4600 b2 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_SUBTYPE_ACK,
4601 IEEE80211_FC0_SUBTYPE_MASK);
4602 gen_not(b2);
4603 gen_and(b1, b2);
4604 gen_or(b0, b2);
4605 b1 = gen_bcmp(cstate, OR_LINKHDR, 10, 6, eaddr);
4606 gen_and(b2, b1);
4607 return b1;
4608
4609 case Q_ADDR3:
4610 /*
4611 * Not present in control frames.
4612 */
4613 b0 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_TYPE_CTL,
4614 IEEE80211_FC0_TYPE_MASK);
4615 gen_not(b0);
4616 b1 = gen_bcmp(cstate, OR_LINKHDR, 16, 6, eaddr);
4617 gen_and(b0, b1);
4618 return b1;
4619
4620 case Q_ADDR4:
4621 /*
4622 * Present only if the direction mask has both "From DS"
4623 * and "To DS" set. Neither control frames nor management
4624 * frames should have both of those set, so we don't
4625 * check the frame type.
4626 */
4627 b0 = gen_mcmp(cstate, OR_LINKHDR, 1, BPF_B,
4628 IEEE80211_FC1_DIR_DSTODS, IEEE80211_FC1_DIR_MASK);
4629 b1 = gen_bcmp(cstate, OR_LINKHDR, 24, 6, eaddr);
4630 gen_and(b0, b1);
4631 return b1;
4632
4633 case Q_RA:
4634 /*
4635 * Not present in management frames; addr1 in other
4636 * frames.
4637 */
4638
4639 /*
4640 * If the high-order bit of the type value is 0, this
4641 * is a management frame.
4642 * I.e, check "(link[0] & 0x08)".
4643 */
4644 s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
4645 b1 = new_block(cstate, JMP(BPF_JSET));
4646 b1->s.k = 0x08;
4647 b1->stmts = s;
4648
4649 /*
4650 * Check addr1.
4651 */
4652 b0 = gen_bcmp(cstate, OR_LINKHDR, 4, 6, eaddr);
4653
4654 /*
4655 * AND that with the check of addr1.
4656 */
4657 gen_and(b1, b0);
4658 return (b0);
4659
4660 case Q_TA:
4661 /*
4662 * Not present in management frames; addr2, if present,
4663 * in other frames.
4664 */
4665
4666 /*
4667 * Not present in CTS or ACK control frames.
4668 */
4669 b0 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_TYPE_CTL,
4670 IEEE80211_FC0_TYPE_MASK);
4671 gen_not(b0);
4672 b1 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_SUBTYPE_CTS,
4673 IEEE80211_FC0_SUBTYPE_MASK);
4674 gen_not(b1);
4675 b2 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, IEEE80211_FC0_SUBTYPE_ACK,
4676 IEEE80211_FC0_SUBTYPE_MASK);
4677 gen_not(b2);
4678 gen_and(b1, b2);
4679 gen_or(b0, b2);
4680
4681 /*
4682 * If the high-order bit of the type value is 0, this
4683 * is a management frame.
4684 * I.e, check "(link[0] & 0x08)".
4685 */
4686 s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
4687 b1 = new_block(cstate, JMP(BPF_JSET));
4688 b1->s.k = 0x08;
4689 b1->stmts = s;
4690
4691 /*
4692 * AND that with the check for frames other than
4693 * CTS and ACK frames.
4694 */
4695 gen_and(b1, b2);
4696
4697 /*
4698 * Check addr2.
4699 */
4700 b1 = gen_bcmp(cstate, OR_LINKHDR, 10, 6, eaddr);
4701 gen_and(b2, b1);
4702 return b1;
4703 }
4704 abort();
4705 /*NOTREACHED*/
4706 }
4707
4708 /*
4709 * Like gen_ehostop, but for RFC 2625 IP-over-Fibre-Channel.
4710 * (We assume that the addresses are IEEE 48-bit MAC addresses,
4711 * as the RFC states.)
4712 */
4713 static struct block *
gen_ipfchostop(compiler_state_t * cstate,const u_char * eaddr,int dir)4714 gen_ipfchostop(compiler_state_t *cstate, const u_char *eaddr, int dir)
4715 {
4716 register struct block *b0, *b1;
4717
4718 switch (dir) {
4719 case Q_SRC:
4720 return gen_bcmp(cstate, OR_LINKHDR, 10, 6, eaddr);
4721
4722 case Q_DST:
4723 return gen_bcmp(cstate, OR_LINKHDR, 2, 6, eaddr);
4724
4725 case Q_AND:
4726 b0 = gen_ipfchostop(cstate, eaddr, Q_SRC);
4727 b1 = gen_ipfchostop(cstate, eaddr, Q_DST);
4728 gen_and(b0, b1);
4729 return b1;
4730
4731 case Q_DEFAULT:
4732 case Q_OR:
4733 b0 = gen_ipfchostop(cstate, eaddr, Q_SRC);
4734 b1 = gen_ipfchostop(cstate, eaddr, Q_DST);
4735 gen_or(b0, b1);
4736 return b1;
4737
4738 case Q_ADDR1:
4739 bpf_error(cstate, "'addr1' and 'address1' are only supported on 802.11");
4740 /*NOTREACHED*/
4741
4742 case Q_ADDR2:
4743 bpf_error(cstate, "'addr2' and 'address2' are only supported on 802.11");
4744 /*NOTREACHED*/
4745
4746 case Q_ADDR3:
4747 bpf_error(cstate, "'addr3' and 'address3' are only supported on 802.11");
4748 /*NOTREACHED*/
4749
4750 case Q_ADDR4:
4751 bpf_error(cstate, "'addr4' and 'address4' are only supported on 802.11");
4752 /*NOTREACHED*/
4753
4754 case Q_RA:
4755 bpf_error(cstate, "'ra' is only supported on 802.11");
4756 /*NOTREACHED*/
4757
4758 case Q_TA:
4759 bpf_error(cstate, "'ta' is only supported on 802.11");
4760 /*NOTREACHED*/
4761 }
4762 abort();
4763 /*NOTREACHED*/
4764 }
4765
4766 /*
4767 * This is quite tricky because there may be pad bytes in front of the
4768 * DECNET header, and then there are two possible data packet formats that
4769 * carry both src and dst addresses, plus 5 packet types in a format that
4770 * carries only the src node, plus 2 types that use a different format and
4771 * also carry just the src node.
4772 *
4773 * Yuck.
4774 *
4775 * Instead of doing those all right, we just look for data packets with
4776 * 0 or 1 bytes of padding. If you want to look at other packets, that
4777 * will require a lot more hacking.
4778 *
4779 * To add support for filtering on DECNET "areas" (network numbers)
4780 * one would want to add a "mask" argument to this routine. That would
4781 * make the filter even more inefficient, although one could be clever
4782 * and not generate masking instructions if the mask is 0xFFFF.
4783 */
4784 static struct block *
gen_dnhostop(compiler_state_t * cstate,bpf_u_int32 addr,int dir)4785 gen_dnhostop(compiler_state_t *cstate, bpf_u_int32 addr, int dir)
4786 {
4787 struct block *b0, *b1, *b2, *tmp;
4788 u_int offset_lh; /* offset if long header is received */
4789 u_int offset_sh; /* offset if short header is received */
4790
4791 switch (dir) {
4792
4793 case Q_DST:
4794 offset_sh = 1; /* follows flags */
4795 offset_lh = 7; /* flgs,darea,dsubarea,HIORD */
4796 break;
4797
4798 case Q_SRC:
4799 offset_sh = 3; /* follows flags, dstnode */
4800 offset_lh = 15; /* flgs,darea,dsubarea,did,sarea,ssub,HIORD */
4801 break;
4802
4803 case Q_AND:
4804 /* Inefficient because we do our Calvinball dance twice */
4805 b0 = gen_dnhostop(cstate, addr, Q_SRC);
4806 b1 = gen_dnhostop(cstate, addr, Q_DST);
4807 gen_and(b0, b1);
4808 return b1;
4809
4810 case Q_DEFAULT:
4811 case Q_OR:
4812 /* Inefficient because we do our Calvinball dance twice */
4813 b0 = gen_dnhostop(cstate, addr, Q_SRC);
4814 b1 = gen_dnhostop(cstate, addr, Q_DST);
4815 gen_or(b0, b1);
4816 return b1;
4817
4818 case Q_ADDR1:
4819 bpf_error(cstate, "'addr1' and 'address1' are not valid qualifiers for addresses other than 802.11 MAC addresses");
4820 /*NOTREACHED*/
4821
4822 case Q_ADDR2:
4823 bpf_error(cstate, "'addr2' and 'address2' are not valid qualifiers for addresses other than 802.11 MAC addresses");
4824 /*NOTREACHED*/
4825
4826 case Q_ADDR3:
4827 bpf_error(cstate, "'addr3' and 'address3' are not valid qualifiers for addresses other than 802.11 MAC addresses");
4828 /*NOTREACHED*/
4829
4830 case Q_ADDR4:
4831 bpf_error(cstate, "'addr4' and 'address4' are not valid qualifiers for addresses other than 802.11 MAC addresses");
4832 /*NOTREACHED*/
4833
4834 case Q_RA:
4835 bpf_error(cstate, "'ra' is not a valid qualifier for addresses other than 802.11 MAC addresses");
4836 /*NOTREACHED*/
4837
4838 case Q_TA:
4839 bpf_error(cstate, "'ta' is not a valid qualifier for addresses other than 802.11 MAC addresses");
4840 /*NOTREACHED*/
4841
4842 default:
4843 abort();
4844 /*NOTREACHED*/
4845 }
4846 b0 = gen_linktype(cstate, ETHERTYPE_DN);
4847 /* Check for pad = 1, long header case */
4848 tmp = gen_mcmp(cstate, OR_LINKPL, 2, BPF_H,
4849 (bpf_int32)ntohs(0x0681), (bpf_int32)ntohs(0x07FF));
4850 b1 = gen_cmp(cstate, OR_LINKPL, 2 + 1 + offset_lh,
4851 BPF_H, (bpf_int32)ntohs((u_short)addr));
4852 gen_and(tmp, b1);
4853 /* Check for pad = 0, long header case */
4854 tmp = gen_mcmp(cstate, OR_LINKPL, 2, BPF_B, (bpf_int32)0x06, (bpf_int32)0x7);
4855 b2 = gen_cmp(cstate, OR_LINKPL, 2 + offset_lh, BPF_H, (bpf_int32)ntohs((u_short)addr));
4856 gen_and(tmp, b2);
4857 gen_or(b2, b1);
4858 /* Check for pad = 1, short header case */
4859 tmp = gen_mcmp(cstate, OR_LINKPL, 2, BPF_H,
4860 (bpf_int32)ntohs(0x0281), (bpf_int32)ntohs(0x07FF));
4861 b2 = gen_cmp(cstate, OR_LINKPL, 2 + 1 + offset_sh, BPF_H, (bpf_int32)ntohs((u_short)addr));
4862 gen_and(tmp, b2);
4863 gen_or(b2, b1);
4864 /* Check for pad = 0, short header case */
4865 tmp = gen_mcmp(cstate, OR_LINKPL, 2, BPF_B, (bpf_int32)0x02, (bpf_int32)0x7);
4866 b2 = gen_cmp(cstate, OR_LINKPL, 2 + offset_sh, BPF_H, (bpf_int32)ntohs((u_short)addr));
4867 gen_and(tmp, b2);
4868 gen_or(b2, b1);
4869
4870 /* Combine with test for cstate->linktype */
4871 gen_and(b0, b1);
4872 return b1;
4873 }
4874
4875 /*
4876 * Generate a check for IPv4 or IPv6 for MPLS-encapsulated packets;
4877 * test the bottom-of-stack bit, and then check the version number
4878 * field in the IP header.
4879 */
4880 static struct block *
gen_mpls_linktype(compiler_state_t * cstate,int proto)4881 gen_mpls_linktype(compiler_state_t *cstate, int proto)
4882 {
4883 struct block *b0, *b1;
4884
4885 switch (proto) {
4886
4887 case Q_IP:
4888 /* match the bottom-of-stack bit */
4889 b0 = gen_mcmp(cstate, OR_LINKPL, (u_int)-2, BPF_B, 0x01, 0x01);
4890 /* match the IPv4 version number */
4891 b1 = gen_mcmp(cstate, OR_LINKPL, 0, BPF_B, 0x40, 0xf0);
4892 gen_and(b0, b1);
4893 return b1;
4894
4895 case Q_IPV6:
4896 /* match the bottom-of-stack bit */
4897 b0 = gen_mcmp(cstate, OR_LINKPL, (u_int)-2, BPF_B, 0x01, 0x01);
4898 /* match the IPv4 version number */
4899 b1 = gen_mcmp(cstate, OR_LINKPL, 0, BPF_B, 0x60, 0xf0);
4900 gen_and(b0, b1);
4901 return b1;
4902
4903 default:
4904 abort();
4905 }
4906 }
4907
4908 static struct block *
gen_host(compiler_state_t * cstate,bpf_u_int32 addr,bpf_u_int32 mask,int proto,int dir,int type)4909 gen_host(compiler_state_t *cstate, bpf_u_int32 addr, bpf_u_int32 mask,
4910 int proto, int dir, int type)
4911 {
4912 struct block *b0, *b1;
4913 const char *typestr;
4914
4915 if (type == Q_NET)
4916 typestr = "net";
4917 else
4918 typestr = "host";
4919
4920 switch (proto) {
4921
4922 case Q_DEFAULT:
4923 b0 = gen_host(cstate, addr, mask, Q_IP, dir, type);
4924 /*
4925 * Only check for non-IPv4 addresses if we're not
4926 * checking MPLS-encapsulated packets.
4927 */
4928 if (cstate->label_stack_depth == 0) {
4929 b1 = gen_host(cstate, addr, mask, Q_ARP, dir, type);
4930 gen_or(b0, b1);
4931 b0 = gen_host(cstate, addr, mask, Q_RARP, dir, type);
4932 gen_or(b1, b0);
4933 }
4934 return b0;
4935
4936 case Q_LINK:
4937 bpf_error(cstate, "link-layer modifier applied to %s", typestr);
4938
4939 case Q_IP:
4940 return gen_hostop(cstate, addr, mask, dir, ETHERTYPE_IP, 12, 16);
4941
4942 case Q_RARP:
4943 return gen_hostop(cstate, addr, mask, dir, ETHERTYPE_REVARP, 14, 24);
4944
4945 case Q_ARP:
4946 return gen_hostop(cstate, addr, mask, dir, ETHERTYPE_ARP, 14, 24);
4947
4948 case Q_SCTP:
4949 bpf_error(cstate, "'sctp' modifier applied to %s", typestr);
4950
4951 case Q_TCP:
4952 bpf_error(cstate, "'tcp' modifier applied to %s", typestr);
4953
4954 case Q_UDP:
4955 bpf_error(cstate, "'udp' modifier applied to %s", typestr);
4956
4957 case Q_ICMP:
4958 bpf_error(cstate, "'icmp' modifier applied to %s", typestr);
4959
4960 case Q_IGMP:
4961 bpf_error(cstate, "'igmp' modifier applied to %s", typestr);
4962
4963 case Q_IGRP:
4964 bpf_error(cstate, "'igrp' modifier applied to %s", typestr);
4965
4966 case Q_ATALK:
4967 bpf_error(cstate, "AppleTalk host filtering not implemented");
4968
4969 case Q_DECNET:
4970 return gen_dnhostop(cstate, addr, dir);
4971
4972 case Q_LAT:
4973 bpf_error(cstate, "LAT host filtering not implemented");
4974
4975 case Q_SCA:
4976 bpf_error(cstate, "SCA host filtering not implemented");
4977
4978 case Q_MOPRC:
4979 bpf_error(cstate, "MOPRC host filtering not implemented");
4980
4981 case Q_MOPDL:
4982 bpf_error(cstate, "MOPDL host filtering not implemented");
4983
4984 case Q_IPV6:
4985 bpf_error(cstate, "'ip6' modifier applied to ip host");
4986
4987 case Q_ICMPV6:
4988 bpf_error(cstate, "'icmp6' modifier applied to %s", typestr);
4989
4990 case Q_AH:
4991 bpf_error(cstate, "'ah' modifier applied to %s", typestr);
4992
4993 case Q_ESP:
4994 bpf_error(cstate, "'esp' modifier applied to %s", typestr);
4995
4996 case Q_PIM:
4997 bpf_error(cstate, "'pim' modifier applied to %s", typestr);
4998
4999 case Q_VRRP:
5000 bpf_error(cstate, "'vrrp' modifier applied to %s", typestr);
5001
5002 case Q_AARP:
5003 bpf_error(cstate, "AARP host filtering not implemented");
5004
5005 case Q_ISO:
5006 bpf_error(cstate, "ISO host filtering not implemented");
5007
5008 case Q_ESIS:
5009 bpf_error(cstate, "'esis' modifier applied to %s", typestr);
5010
5011 case Q_ISIS:
5012 bpf_error(cstate, "'isis' modifier applied to %s", typestr);
5013
5014 case Q_CLNP:
5015 bpf_error(cstate, "'clnp' modifier applied to %s", typestr);
5016
5017 case Q_STP:
5018 bpf_error(cstate, "'stp' modifier applied to %s", typestr);
5019
5020 case Q_IPX:
5021 bpf_error(cstate, "IPX host filtering not implemented");
5022
5023 case Q_NETBEUI:
5024 bpf_error(cstate, "'netbeui' modifier applied to %s", typestr);
5025
5026 case Q_ISIS_L1:
5027 bpf_error(cstate, "'l1' modifier applied to %s", typestr);
5028
5029 case Q_ISIS_L2:
5030 bpf_error(cstate, "'l2' modifier applied to %s", typestr);
5031
5032 case Q_ISIS_IIH:
5033 bpf_error(cstate, "'iih' modifier applied to %s", typestr);
5034
5035 case Q_ISIS_SNP:
5036 bpf_error(cstate, "'snp' modifier applied to %s", typestr);
5037
5038 case Q_ISIS_CSNP:
5039 bpf_error(cstate, "'csnp' modifier applied to %s", typestr);
5040
5041 case Q_ISIS_PSNP:
5042 bpf_error(cstate, "'psnp' modifier applied to %s", typestr);
5043
5044 case Q_ISIS_LSP:
5045 bpf_error(cstate, "'lsp' modifier applied to %s", typestr);
5046
5047 case Q_RADIO:
5048 bpf_error(cstate, "'radio' modifier applied to %s", typestr);
5049
5050 case Q_CARP:
5051 bpf_error(cstate, "'carp' modifier applied to %s", typestr);
5052
5053 default:
5054 abort();
5055 }
5056 /*NOTREACHED*/
5057 }
5058
5059 #ifdef INET6
5060 static struct block *
gen_host6(compiler_state_t * cstate,struct in6_addr * addr,struct in6_addr * mask,int proto,int dir,int type)5061 gen_host6(compiler_state_t *cstate, struct in6_addr *addr,
5062 struct in6_addr *mask, int proto, int dir, int type)
5063 {
5064 const char *typestr;
5065
5066 if (type == Q_NET)
5067 typestr = "net";
5068 else
5069 typestr = "host";
5070
5071 switch (proto) {
5072
5073 case Q_DEFAULT:
5074 return gen_host6(cstate, addr, mask, Q_IPV6, dir, type);
5075
5076 case Q_LINK:
5077 bpf_error(cstate, "link-layer modifier applied to ip6 %s", typestr);
5078
5079 case Q_IP:
5080 bpf_error(cstate, "'ip' modifier applied to ip6 %s", typestr);
5081
5082 case Q_RARP:
5083 bpf_error(cstate, "'rarp' modifier applied to ip6 %s", typestr);
5084
5085 case Q_ARP:
5086 bpf_error(cstate, "'arp' modifier applied to ip6 %s", typestr);
5087
5088 case Q_SCTP:
5089 bpf_error(cstate, "'sctp' modifier applied to ip6 %s", typestr);
5090
5091 case Q_TCP:
5092 bpf_error(cstate, "'tcp' modifier applied to ip6 %s", typestr);
5093
5094 case Q_UDP:
5095 bpf_error(cstate, "'udp' modifier applied to ip6 %s", typestr);
5096
5097 case Q_ICMP:
5098 bpf_error(cstate, "'icmp' modifier applied to ip6 %s", typestr);
5099
5100 case Q_IGMP:
5101 bpf_error(cstate, "'igmp' modifier applied to ip6 %s", typestr);
5102
5103 case Q_IGRP:
5104 bpf_error(cstate, "'igrp' modifier applied to ip6 %s", typestr);
5105
5106 case Q_ATALK:
5107 bpf_error(cstate, "AppleTalk modifier applied to ip6 %s", typestr);
5108
5109 case Q_DECNET:
5110 bpf_error(cstate, "'decnet' modifier applied to ip6 %s", typestr);
5111
5112 case Q_LAT:
5113 bpf_error(cstate, "'lat' modifier applied to ip6 %s", typestr);
5114
5115 case Q_SCA:
5116 bpf_error(cstate, "'sca' modifier applied to ip6 %s", typestr);
5117
5118 case Q_MOPRC:
5119 bpf_error(cstate, "'moprc' modifier applied to ip6 %s", typestr);
5120
5121 case Q_MOPDL:
5122 bpf_error(cstate, "'mopdl' modifier applied to ip6 %s", typestr);
5123
5124 case Q_IPV6:
5125 return gen_hostop6(cstate, addr, mask, dir, ETHERTYPE_IPV6, 8, 24);
5126
5127 case Q_ICMPV6:
5128 bpf_error(cstate, "'icmp6' modifier applied to ip6 %s", typestr);
5129
5130 case Q_AH:
5131 bpf_error(cstate, "'ah' modifier applied to ip6 %s", typestr);
5132
5133 case Q_ESP:
5134 bpf_error(cstate, "'esp' modifier applied to ip6 %s", typestr);
5135
5136 case Q_PIM:
5137 bpf_error(cstate, "'pim' modifier applied to ip6 %s", typestr);
5138
5139 case Q_VRRP:
5140 bpf_error(cstate, "'vrrp' modifier applied to ip6 %s", typestr);
5141
5142 case Q_AARP:
5143 bpf_error(cstate, "'aarp' modifier applied to ip6 %s", typestr);
5144
5145 case Q_ISO:
5146 bpf_error(cstate, "'iso' modifier applied to ip6 %s", typestr);
5147
5148 case Q_ESIS:
5149 bpf_error(cstate, "'esis' modifier applied to ip6 %s", typestr);
5150
5151 case Q_ISIS:
5152 bpf_error(cstate, "'isis' modifier applied to ip6 %s", typestr);
5153
5154 case Q_CLNP:
5155 bpf_error(cstate, "'clnp' modifier applied to ip6 %s", typestr);
5156
5157 case Q_STP:
5158 bpf_error(cstate, "'stp' modifier applied to ip6 %s", typestr);
5159
5160 case Q_IPX:
5161 bpf_error(cstate, "'ipx' modifier applied to ip6 %s", typestr);
5162
5163 case Q_NETBEUI:
5164 bpf_error(cstate, "'netbeui' modifier applied to ip6 %s", typestr);
5165
5166 case Q_ISIS_L1:
5167 bpf_error(cstate, "'l1' modifier applied to ip6 %s", typestr);
5168
5169 case Q_ISIS_L2:
5170 bpf_error(cstate, "'l2' modifier applied to ip6 %s", typestr);
5171
5172 case Q_ISIS_IIH:
5173 bpf_error(cstate, "'iih' modifier applied to ip6 %s", typestr);
5174
5175 case Q_ISIS_SNP:
5176 bpf_error(cstate, "'snp' modifier applied to ip6 %s", typestr);
5177
5178 case Q_ISIS_CSNP:
5179 bpf_error(cstate, "'csnp' modifier applied to ip6 %s", typestr);
5180
5181 case Q_ISIS_PSNP:
5182 bpf_error(cstate, "'psnp' modifier applied to ip6 %s", typestr);
5183
5184 case Q_ISIS_LSP:
5185 bpf_error(cstate, "'lsp' modifier applied to ip6 %s", typestr);
5186
5187 case Q_RADIO:
5188 bpf_error(cstate, "'radio' modifier applied to ip6 %s", typestr);
5189
5190 case Q_CARP:
5191 bpf_error(cstate, "'carp' modifier applied to ip6 %s", typestr);
5192
5193 default:
5194 abort();
5195 }
5196 /*NOTREACHED*/
5197 }
5198 #endif
5199
5200 #ifndef INET6
5201 static struct block *
gen_gateway(compiler_state_t * cstate,const u_char * eaddr,struct addrinfo * alist,int proto,int dir)5202 gen_gateway(compiler_state_t *cstate, const u_char *eaddr,
5203 struct addrinfo *alist, int proto, int dir)
5204 {
5205 struct block *b0, *b1, *tmp;
5206 struct addrinfo *ai;
5207 struct sockaddr_in *sin;
5208
5209 if (dir != 0)
5210 bpf_error(cstate, "direction applied to 'gateway'");
5211
5212 switch (proto) {
5213 case Q_DEFAULT:
5214 case Q_IP:
5215 case Q_ARP:
5216 case Q_RARP:
5217 switch (cstate->linktype) {
5218 case DLT_EN10MB:
5219 case DLT_NETANALYZER:
5220 case DLT_NETANALYZER_TRANSPARENT:
5221 b1 = gen_prevlinkhdr_check(cstate);
5222 b0 = gen_ehostop(cstate, eaddr, Q_OR);
5223 if (b1 != NULL)
5224 gen_and(b1, b0);
5225 break;
5226 case DLT_FDDI:
5227 b0 = gen_fhostop(cstate, eaddr, Q_OR);
5228 break;
5229 case DLT_IEEE802:
5230 b0 = gen_thostop(cstate, eaddr, Q_OR);
5231 break;
5232 case DLT_IEEE802_11:
5233 case DLT_PRISM_HEADER:
5234 case DLT_IEEE802_11_RADIO_AVS:
5235 case DLT_IEEE802_11_RADIO:
5236 case DLT_PPI:
5237 b0 = gen_wlanhostop(cstate, eaddr, Q_OR);
5238 break;
5239 case DLT_SUNATM:
5240 /*
5241 * This is LLC-multiplexed traffic; if it were
5242 * LANE, cstate->linktype would have been set to
5243 * DLT_EN10MB.
5244 */
5245 bpf_error(cstate,
5246 "'gateway' supported only on ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel");
5247 break;
5248 case DLT_IP_OVER_FC:
5249 b0 = gen_ipfchostop(cstate, eaddr, Q_OR);
5250 break;
5251 default:
5252 bpf_error(cstate,
5253 "'gateway' supported only on ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel");
5254 }
5255 b1 = NULL;
5256 for (ai = alist; ai != NULL; ai = ai->ai_next) {
5257 /*
5258 * Does it have an address?
5259 */
5260 if (ai->ai_addr != NULL) {
5261 /*
5262 * Yes. Is it an IPv4 address?
5263 */
5264 if (ai->ai_addr->sa_family == AF_INET) {
5265 /*
5266 * Generate an entry for it.
5267 */
5268 sin = (struct sockaddr_in *)ai->ai_addr;
5269 tmp = gen_host(cstate,
5270 ntohl(sin->sin_addr.s_addr),
5271 0xffffffff, proto, Q_OR, Q_HOST);
5272 /*
5273 * Is it the *first* IPv4 address?
5274 */
5275 if (b1 == NULL) {
5276 /*
5277 * Yes, so start with it.
5278 */
5279 b1 = tmp;
5280 } else {
5281 /*
5282 * No, so OR it into the
5283 * existing set of
5284 * addresses.
5285 */
5286 gen_or(b1, tmp);
5287 b1 = tmp;
5288 }
5289 }
5290 }
5291 }
5292 if (b1 == NULL) {
5293 /*
5294 * No IPv4 addresses found.
5295 */
5296 return (NULL);
5297 }
5298 gen_not(b1);
5299 gen_and(b0, b1);
5300 return b1;
5301 }
5302 bpf_error(cstate, "illegal modifier of 'gateway'");
5303 /*NOTREACHED*/
5304 }
5305 #endif
5306
5307 static struct block *
gen_proto_abbrev_internal(compiler_state_t * cstate,int proto)5308 gen_proto_abbrev_internal(compiler_state_t *cstate, int proto)
5309 {
5310 struct block *b0;
5311 struct block *b1;
5312
5313 switch (proto) {
5314
5315 case Q_SCTP:
5316 b1 = gen_proto(cstate, IPPROTO_SCTP, Q_IP, Q_DEFAULT);
5317 b0 = gen_proto(cstate, IPPROTO_SCTP, Q_IPV6, Q_DEFAULT);
5318 gen_or(b0, b1);
5319 break;
5320
5321 case Q_TCP:
5322 b1 = gen_proto(cstate, IPPROTO_TCP, Q_IP, Q_DEFAULT);
5323 b0 = gen_proto(cstate, IPPROTO_TCP, Q_IPV6, Q_DEFAULT);
5324 gen_or(b0, b1);
5325 break;
5326
5327 case Q_UDP:
5328 b1 = gen_proto(cstate, IPPROTO_UDP, Q_IP, Q_DEFAULT);
5329 b0 = gen_proto(cstate, IPPROTO_UDP, Q_IPV6, Q_DEFAULT);
5330 gen_or(b0, b1);
5331 break;
5332
5333 case Q_ICMP:
5334 b1 = gen_proto(cstate, IPPROTO_ICMP, Q_IP, Q_DEFAULT);
5335 break;
5336
5337 #ifndef IPPROTO_IGMP
5338 #define IPPROTO_IGMP 2
5339 #endif
5340
5341 case Q_IGMP:
5342 b1 = gen_proto(cstate, IPPROTO_IGMP, Q_IP, Q_DEFAULT);
5343 break;
5344
5345 #ifndef IPPROTO_IGRP
5346 #define IPPROTO_IGRP 9
5347 #endif
5348 case Q_IGRP:
5349 b1 = gen_proto(cstate, IPPROTO_IGRP, Q_IP, Q_DEFAULT);
5350 break;
5351
5352 #ifndef IPPROTO_PIM
5353 #define IPPROTO_PIM 103
5354 #endif
5355
5356 case Q_PIM:
5357 b1 = gen_proto(cstate, IPPROTO_PIM, Q_IP, Q_DEFAULT);
5358 b0 = gen_proto(cstate, IPPROTO_PIM, Q_IPV6, Q_DEFAULT);
5359 gen_or(b0, b1);
5360 break;
5361
5362 #ifndef IPPROTO_VRRP
5363 #define IPPROTO_VRRP 112
5364 #endif
5365
5366 case Q_VRRP:
5367 b1 = gen_proto(cstate, IPPROTO_VRRP, Q_IP, Q_DEFAULT);
5368 break;
5369
5370 #ifndef IPPROTO_CARP
5371 #define IPPROTO_CARP 112
5372 #endif
5373
5374 case Q_CARP:
5375 b1 = gen_proto(cstate, IPPROTO_CARP, Q_IP, Q_DEFAULT);
5376 break;
5377
5378 case Q_IP:
5379 b1 = gen_linktype(cstate, ETHERTYPE_IP);
5380 break;
5381
5382 case Q_ARP:
5383 b1 = gen_linktype(cstate, ETHERTYPE_ARP);
5384 break;
5385
5386 case Q_RARP:
5387 b1 = gen_linktype(cstate, ETHERTYPE_REVARP);
5388 break;
5389
5390 case Q_LINK:
5391 bpf_error(cstate, "link layer applied in wrong context");
5392
5393 case Q_ATALK:
5394 b1 = gen_linktype(cstate, ETHERTYPE_ATALK);
5395 break;
5396
5397 case Q_AARP:
5398 b1 = gen_linktype(cstate, ETHERTYPE_AARP);
5399 break;
5400
5401 case Q_DECNET:
5402 b1 = gen_linktype(cstate, ETHERTYPE_DN);
5403 break;
5404
5405 case Q_SCA:
5406 b1 = gen_linktype(cstate, ETHERTYPE_SCA);
5407 break;
5408
5409 case Q_LAT:
5410 b1 = gen_linktype(cstate, ETHERTYPE_LAT);
5411 break;
5412
5413 case Q_MOPDL:
5414 b1 = gen_linktype(cstate, ETHERTYPE_MOPDL);
5415 break;
5416
5417 case Q_MOPRC:
5418 b1 = gen_linktype(cstate, ETHERTYPE_MOPRC);
5419 break;
5420
5421 case Q_IPV6:
5422 b1 = gen_linktype(cstate, ETHERTYPE_IPV6);
5423 break;
5424
5425 #ifndef IPPROTO_ICMPV6
5426 #define IPPROTO_ICMPV6 58
5427 #endif
5428 case Q_ICMPV6:
5429 b1 = gen_proto(cstate, IPPROTO_ICMPV6, Q_IPV6, Q_DEFAULT);
5430 break;
5431
5432 #ifndef IPPROTO_AH
5433 #define IPPROTO_AH 51
5434 #endif
5435 case Q_AH:
5436 b1 = gen_proto(cstate, IPPROTO_AH, Q_IP, Q_DEFAULT);
5437 b0 = gen_proto(cstate, IPPROTO_AH, Q_IPV6, Q_DEFAULT);
5438 gen_or(b0, b1);
5439 break;
5440
5441 #ifndef IPPROTO_ESP
5442 #define IPPROTO_ESP 50
5443 #endif
5444 case Q_ESP:
5445 b1 = gen_proto(cstate, IPPROTO_ESP, Q_IP, Q_DEFAULT);
5446 b0 = gen_proto(cstate, IPPROTO_ESP, Q_IPV6, Q_DEFAULT);
5447 gen_or(b0, b1);
5448 break;
5449
5450 case Q_ISO:
5451 b1 = gen_linktype(cstate, LLCSAP_ISONS);
5452 break;
5453
5454 case Q_ESIS:
5455 b1 = gen_proto(cstate, ISO9542_ESIS, Q_ISO, Q_DEFAULT);
5456 break;
5457
5458 case Q_ISIS:
5459 b1 = gen_proto(cstate, ISO10589_ISIS, Q_ISO, Q_DEFAULT);
5460 break;
5461
5462 case Q_ISIS_L1: /* all IS-IS Level1 PDU-Types */
5463 b0 = gen_proto(cstate, ISIS_L1_LAN_IIH, Q_ISIS, Q_DEFAULT);
5464 b1 = gen_proto(cstate, ISIS_PTP_IIH, Q_ISIS, Q_DEFAULT); /* FIXME extract the circuit-type bits */
5465 gen_or(b0, b1);
5466 b0 = gen_proto(cstate, ISIS_L1_LSP, Q_ISIS, Q_DEFAULT);
5467 gen_or(b0, b1);
5468 b0 = gen_proto(cstate, ISIS_L1_CSNP, Q_ISIS, Q_DEFAULT);
5469 gen_or(b0, b1);
5470 b0 = gen_proto(cstate, ISIS_L1_PSNP, Q_ISIS, Q_DEFAULT);
5471 gen_or(b0, b1);
5472 break;
5473
5474 case Q_ISIS_L2: /* all IS-IS Level2 PDU-Types */
5475 b0 = gen_proto(cstate, ISIS_L2_LAN_IIH, Q_ISIS, Q_DEFAULT);
5476 b1 = gen_proto(cstate, ISIS_PTP_IIH, Q_ISIS, Q_DEFAULT); /* FIXME extract the circuit-type bits */
5477 gen_or(b0, b1);
5478 b0 = gen_proto(cstate, ISIS_L2_LSP, Q_ISIS, Q_DEFAULT);
5479 gen_or(b0, b1);
5480 b0 = gen_proto(cstate, ISIS_L2_CSNP, Q_ISIS, Q_DEFAULT);
5481 gen_or(b0, b1);
5482 b0 = gen_proto(cstate, ISIS_L2_PSNP, Q_ISIS, Q_DEFAULT);
5483 gen_or(b0, b1);
5484 break;
5485
5486 case Q_ISIS_IIH: /* all IS-IS Hello PDU-Types */
5487 b0 = gen_proto(cstate, ISIS_L1_LAN_IIH, Q_ISIS, Q_DEFAULT);
5488 b1 = gen_proto(cstate, ISIS_L2_LAN_IIH, Q_ISIS, Q_DEFAULT);
5489 gen_or(b0, b1);
5490 b0 = gen_proto(cstate, ISIS_PTP_IIH, Q_ISIS, Q_DEFAULT);
5491 gen_or(b0, b1);
5492 break;
5493
5494 case Q_ISIS_LSP:
5495 b0 = gen_proto(cstate, ISIS_L1_LSP, Q_ISIS, Q_DEFAULT);
5496 b1 = gen_proto(cstate, ISIS_L2_LSP, Q_ISIS, Q_DEFAULT);
5497 gen_or(b0, b1);
5498 break;
5499
5500 case Q_ISIS_SNP:
5501 b0 = gen_proto(cstate, ISIS_L1_CSNP, Q_ISIS, Q_DEFAULT);
5502 b1 = gen_proto(cstate, ISIS_L2_CSNP, Q_ISIS, Q_DEFAULT);
5503 gen_or(b0, b1);
5504 b0 = gen_proto(cstate, ISIS_L1_PSNP, Q_ISIS, Q_DEFAULT);
5505 gen_or(b0, b1);
5506 b0 = gen_proto(cstate, ISIS_L2_PSNP, Q_ISIS, Q_DEFAULT);
5507 gen_or(b0, b1);
5508 break;
5509
5510 case Q_ISIS_CSNP:
5511 b0 = gen_proto(cstate, ISIS_L1_CSNP, Q_ISIS, Q_DEFAULT);
5512 b1 = gen_proto(cstate, ISIS_L2_CSNP, Q_ISIS, Q_DEFAULT);
5513 gen_or(b0, b1);
5514 break;
5515
5516 case Q_ISIS_PSNP:
5517 b0 = gen_proto(cstate, ISIS_L1_PSNP, Q_ISIS, Q_DEFAULT);
5518 b1 = gen_proto(cstate, ISIS_L2_PSNP, Q_ISIS, Q_DEFAULT);
5519 gen_or(b0, b1);
5520 break;
5521
5522 case Q_CLNP:
5523 b1 = gen_proto(cstate, ISO8473_CLNP, Q_ISO, Q_DEFAULT);
5524 break;
5525
5526 case Q_STP:
5527 b1 = gen_linktype(cstate, LLCSAP_8021D);
5528 break;
5529
5530 case Q_IPX:
5531 b1 = gen_linktype(cstate, LLCSAP_IPX);
5532 break;
5533
5534 case Q_NETBEUI:
5535 b1 = gen_linktype(cstate, LLCSAP_NETBEUI);
5536 break;
5537
5538 case Q_RADIO:
5539 bpf_error(cstate, "'radio' is not a valid protocol type");
5540
5541 default:
5542 abort();
5543 }
5544 return b1;
5545 }
5546
5547 struct block *
gen_proto_abbrev(compiler_state_t * cstate,int proto)5548 gen_proto_abbrev(compiler_state_t *cstate, int proto)
5549 {
5550 /*
5551 * Catch errors reported by us and routines below us, and return NULL
5552 * on an error.
5553 */
5554 if (setjmp(cstate->top_ctx))
5555 return (NULL);
5556
5557 return gen_proto_abbrev_internal(cstate, proto);
5558 }
5559
5560 static struct block *
gen_ipfrag(compiler_state_t * cstate)5561 gen_ipfrag(compiler_state_t *cstate)
5562 {
5563 struct slist *s;
5564 struct block *b;
5565
5566 /* not IPv4 frag other than the first frag */
5567 s = gen_load_a(cstate, OR_LINKPL, 6, BPF_H);
5568 b = new_block(cstate, JMP(BPF_JSET));
5569 b->s.k = 0x1fff;
5570 b->stmts = s;
5571 gen_not(b);
5572
5573 return b;
5574 }
5575
5576 /*
5577 * Generate a comparison to a port value in the transport-layer header
5578 * at the specified offset from the beginning of that header.
5579 *
5580 * XXX - this handles a variable-length prefix preceding the link-layer
5581 * header, such as the radiotap or AVS radio prefix, but doesn't handle
5582 * variable-length link-layer headers (such as Token Ring or 802.11
5583 * headers).
5584 */
5585 static struct block *
gen_portatom(compiler_state_t * cstate,int off,bpf_int32 v)5586 gen_portatom(compiler_state_t *cstate, int off, bpf_int32 v)
5587 {
5588 return gen_cmp(cstate, OR_TRAN_IPV4, off, BPF_H, v);
5589 }
5590
5591 static struct block *
gen_portatom6(compiler_state_t * cstate,int off,bpf_int32 v)5592 gen_portatom6(compiler_state_t *cstate, int off, bpf_int32 v)
5593 {
5594 return gen_cmp(cstate, OR_TRAN_IPV6, off, BPF_H, v);
5595 }
5596
5597 struct block *
gen_portop(compiler_state_t * cstate,int port,int proto,int dir)5598 gen_portop(compiler_state_t *cstate, int port, int proto, int dir)
5599 {
5600 struct block *b0, *b1, *tmp;
5601
5602 /* ip proto 'proto' and not a fragment other than the first fragment */
5603 tmp = gen_cmp(cstate, OR_LINKPL, 9, BPF_B, (bpf_int32)proto);
5604 b0 = gen_ipfrag(cstate);
5605 gen_and(tmp, b0);
5606
5607 switch (dir) {
5608 case Q_SRC:
5609 b1 = gen_portatom(cstate, 0, (bpf_int32)port);
5610 break;
5611
5612 case Q_DST:
5613 b1 = gen_portatom(cstate, 2, (bpf_int32)port);
5614 break;
5615
5616 case Q_AND:
5617 tmp = gen_portatom(cstate, 0, (bpf_int32)port);
5618 b1 = gen_portatom(cstate, 2, (bpf_int32)port);
5619 gen_and(tmp, b1);
5620 break;
5621
5622 case Q_DEFAULT:
5623 case Q_OR:
5624 tmp = gen_portatom(cstate, 0, (bpf_int32)port);
5625 b1 = gen_portatom(cstate, 2, (bpf_int32)port);
5626 gen_or(tmp, b1);
5627 break;
5628
5629 case Q_ADDR1:
5630 bpf_error(cstate, "'addr1' and 'address1' are not valid qualifiers for ports");
5631 /*NOTREACHED*/
5632
5633 case Q_ADDR2:
5634 bpf_error(cstate, "'addr2' and 'address2' are not valid qualifiers for ports");
5635 /*NOTREACHED*/
5636
5637 case Q_ADDR3:
5638 bpf_error(cstate, "'addr3' and 'address3' are not valid qualifiers for ports");
5639 /*NOTREACHED*/
5640
5641 case Q_ADDR4:
5642 bpf_error(cstate, "'addr4' and 'address4' are not valid qualifiers for ports");
5643 /*NOTREACHED*/
5644
5645 case Q_RA:
5646 bpf_error(cstate, "'ra' is not a valid qualifier for ports");
5647 /*NOTREACHED*/
5648
5649 case Q_TA:
5650 bpf_error(cstate, "'ta' is not a valid qualifier for ports");
5651 /*NOTREACHED*/
5652
5653 default:
5654 abort();
5655 /*NOTREACHED*/
5656 }
5657 gen_and(b0, b1);
5658
5659 return b1;
5660 }
5661
5662 static struct block *
gen_port(compiler_state_t * cstate,int port,int ip_proto,int dir)5663 gen_port(compiler_state_t *cstate, int port, int ip_proto, int dir)
5664 {
5665 struct block *b0, *b1, *tmp;
5666
5667 /*
5668 * ether proto ip
5669 *
5670 * For FDDI, RFC 1188 says that SNAP encapsulation is used,
5671 * not LLC encapsulation with LLCSAP_IP.
5672 *
5673 * For IEEE 802 networks - which includes 802.5 token ring
5674 * (which is what DLT_IEEE802 means) and 802.11 - RFC 1042
5675 * says that SNAP encapsulation is used, not LLC encapsulation
5676 * with LLCSAP_IP.
5677 *
5678 * For LLC-encapsulated ATM/"Classical IP", RFC 1483 and
5679 * RFC 2225 say that SNAP encapsulation is used, not LLC
5680 * encapsulation with LLCSAP_IP.
5681 *
5682 * So we always check for ETHERTYPE_IP.
5683 */
5684 b0 = gen_linktype(cstate, ETHERTYPE_IP);
5685
5686 switch (ip_proto) {
5687 case IPPROTO_UDP:
5688 case IPPROTO_TCP:
5689 case IPPROTO_SCTP:
5690 b1 = gen_portop(cstate, port, ip_proto, dir);
5691 break;
5692
5693 case PROTO_UNDEF:
5694 tmp = gen_portop(cstate, port, IPPROTO_TCP, dir);
5695 b1 = gen_portop(cstate, port, IPPROTO_UDP, dir);
5696 gen_or(tmp, b1);
5697 tmp = gen_portop(cstate, port, IPPROTO_SCTP, dir);
5698 gen_or(tmp, b1);
5699 break;
5700
5701 default:
5702 abort();
5703 }
5704 gen_and(b0, b1);
5705 return b1;
5706 }
5707
5708 struct block *
gen_portop6(compiler_state_t * cstate,int port,int proto,int dir)5709 gen_portop6(compiler_state_t *cstate, int port, int proto, int dir)
5710 {
5711 struct block *b0, *b1, *tmp;
5712
5713 /* ip6 proto 'proto' */
5714 /* XXX - catch the first fragment of a fragmented packet? */
5715 b0 = gen_cmp(cstate, OR_LINKPL, 6, BPF_B, (bpf_int32)proto);
5716
5717 switch (dir) {
5718 case Q_SRC:
5719 b1 = gen_portatom6(cstate, 0, (bpf_int32)port);
5720 break;
5721
5722 case Q_DST:
5723 b1 = gen_portatom6(cstate, 2, (bpf_int32)port);
5724 break;
5725
5726 case Q_AND:
5727 tmp = gen_portatom6(cstate, 0, (bpf_int32)port);
5728 b1 = gen_portatom6(cstate, 2, (bpf_int32)port);
5729 gen_and(tmp, b1);
5730 break;
5731
5732 case Q_DEFAULT:
5733 case Q_OR:
5734 tmp = gen_portatom6(cstate, 0, (bpf_int32)port);
5735 b1 = gen_portatom6(cstate, 2, (bpf_int32)port);
5736 gen_or(tmp, b1);
5737 break;
5738
5739 default:
5740 abort();
5741 }
5742 gen_and(b0, b1);
5743
5744 return b1;
5745 }
5746
5747 static struct block *
gen_port6(compiler_state_t * cstate,int port,int ip_proto,int dir)5748 gen_port6(compiler_state_t *cstate, int port, int ip_proto, int dir)
5749 {
5750 struct block *b0, *b1, *tmp;
5751
5752 /* link proto ip6 */
5753 b0 = gen_linktype(cstate, ETHERTYPE_IPV6);
5754
5755 switch (ip_proto) {
5756 case IPPROTO_UDP:
5757 case IPPROTO_TCP:
5758 case IPPROTO_SCTP:
5759 b1 = gen_portop6(cstate, port, ip_proto, dir);
5760 break;
5761
5762 case PROTO_UNDEF:
5763 tmp = gen_portop6(cstate, port, IPPROTO_TCP, dir);
5764 b1 = gen_portop6(cstate, port, IPPROTO_UDP, dir);
5765 gen_or(tmp, b1);
5766 tmp = gen_portop6(cstate, port, IPPROTO_SCTP, dir);
5767 gen_or(tmp, b1);
5768 break;
5769
5770 default:
5771 abort();
5772 }
5773 gen_and(b0, b1);
5774 return b1;
5775 }
5776
5777 /* gen_portrange code */
5778 static struct block *
gen_portrangeatom(compiler_state_t * cstate,int off,bpf_int32 v1,bpf_int32 v2)5779 gen_portrangeatom(compiler_state_t *cstate, int off, bpf_int32 v1,
5780 bpf_int32 v2)
5781 {
5782 struct block *b1, *b2;
5783
5784 if (v1 > v2) {
5785 /*
5786 * Reverse the order of the ports, so v1 is the lower one.
5787 */
5788 bpf_int32 vtemp;
5789
5790 vtemp = v1;
5791 v1 = v2;
5792 v2 = vtemp;
5793 }
5794
5795 b1 = gen_cmp_ge(cstate, OR_TRAN_IPV4, off, BPF_H, v1);
5796 b2 = gen_cmp_le(cstate, OR_TRAN_IPV4, off, BPF_H, v2);
5797
5798 gen_and(b1, b2);
5799
5800 return b2;
5801 }
5802
5803 struct block *
gen_portrangeop(compiler_state_t * cstate,int port1,int port2,int proto,int dir)5804 gen_portrangeop(compiler_state_t *cstate, int port1, int port2, int proto,
5805 int dir)
5806 {
5807 struct block *b0, *b1, *tmp;
5808
5809 /* ip proto 'proto' and not a fragment other than the first fragment */
5810 tmp = gen_cmp(cstate, OR_LINKPL, 9, BPF_B, (bpf_int32)proto);
5811 b0 = gen_ipfrag(cstate);
5812 gen_and(tmp, b0);
5813
5814 switch (dir) {
5815 case Q_SRC:
5816 b1 = gen_portrangeatom(cstate, 0, (bpf_int32)port1, (bpf_int32)port2);
5817 break;
5818
5819 case Q_DST:
5820 b1 = gen_portrangeatom(cstate, 2, (bpf_int32)port1, (bpf_int32)port2);
5821 break;
5822
5823 case Q_AND:
5824 tmp = gen_portrangeatom(cstate, 0, (bpf_int32)port1, (bpf_int32)port2);
5825 b1 = gen_portrangeatom(cstate, 2, (bpf_int32)port1, (bpf_int32)port2);
5826 gen_and(tmp, b1);
5827 break;
5828
5829 case Q_DEFAULT:
5830 case Q_OR:
5831 tmp = gen_portrangeatom(cstate, 0, (bpf_int32)port1, (bpf_int32)port2);
5832 b1 = gen_portrangeatom(cstate, 2, (bpf_int32)port1, (bpf_int32)port2);
5833 gen_or(tmp, b1);
5834 break;
5835
5836 case Q_ADDR1:
5837 bpf_error(cstate, "'addr1' and 'address1' are not valid qualifiers for port ranges");
5838 /*NOTREACHED*/
5839
5840 case Q_ADDR2:
5841 bpf_error(cstate, "'addr2' and 'address2' are not valid qualifiers for port ranges");
5842 /*NOTREACHED*/
5843
5844 case Q_ADDR3:
5845 bpf_error(cstate, "'addr3' and 'address3' are not valid qualifiers for port ranges");
5846 /*NOTREACHED*/
5847
5848 case Q_ADDR4:
5849 bpf_error(cstate, "'addr4' and 'address4' are not valid qualifiers for port ranges");
5850 /*NOTREACHED*/
5851
5852 case Q_RA:
5853 bpf_error(cstate, "'ra' is not a valid qualifier for port ranges");
5854 /*NOTREACHED*/
5855
5856 case Q_TA:
5857 bpf_error(cstate, "'ta' is not a valid qualifier for port ranges");
5858 /*NOTREACHED*/
5859
5860 default:
5861 abort();
5862 /*NOTREACHED*/
5863 }
5864 gen_and(b0, b1);
5865
5866 return b1;
5867 }
5868
5869 static struct block *
gen_portrange(compiler_state_t * cstate,int port1,int port2,int ip_proto,int dir)5870 gen_portrange(compiler_state_t *cstate, int port1, int port2, int ip_proto,
5871 int dir)
5872 {
5873 struct block *b0, *b1, *tmp;
5874
5875 /* link proto ip */
5876 b0 = gen_linktype(cstate, ETHERTYPE_IP);
5877
5878 switch (ip_proto) {
5879 case IPPROTO_UDP:
5880 case IPPROTO_TCP:
5881 case IPPROTO_SCTP:
5882 b1 = gen_portrangeop(cstate, port1, port2, ip_proto, dir);
5883 break;
5884
5885 case PROTO_UNDEF:
5886 tmp = gen_portrangeop(cstate, port1, port2, IPPROTO_TCP, dir);
5887 b1 = gen_portrangeop(cstate, port1, port2, IPPROTO_UDP, dir);
5888 gen_or(tmp, b1);
5889 tmp = gen_portrangeop(cstate, port1, port2, IPPROTO_SCTP, dir);
5890 gen_or(tmp, b1);
5891 break;
5892
5893 default:
5894 abort();
5895 }
5896 gen_and(b0, b1);
5897 return b1;
5898 }
5899
5900 static struct block *
gen_portrangeatom6(compiler_state_t * cstate,int off,bpf_int32 v1,bpf_int32 v2)5901 gen_portrangeatom6(compiler_state_t *cstate, int off, bpf_int32 v1,
5902 bpf_int32 v2)
5903 {
5904 struct block *b1, *b2;
5905
5906 if (v1 > v2) {
5907 /*
5908 * Reverse the order of the ports, so v1 is the lower one.
5909 */
5910 bpf_int32 vtemp;
5911
5912 vtemp = v1;
5913 v1 = v2;
5914 v2 = vtemp;
5915 }
5916
5917 b1 = gen_cmp_ge(cstate, OR_TRAN_IPV6, off, BPF_H, v1);
5918 b2 = gen_cmp_le(cstate, OR_TRAN_IPV6, off, BPF_H, v2);
5919
5920 gen_and(b1, b2);
5921
5922 return b2;
5923 }
5924
5925 struct block *
gen_portrangeop6(compiler_state_t * cstate,int port1,int port2,int proto,int dir)5926 gen_portrangeop6(compiler_state_t *cstate, int port1, int port2, int proto,
5927 int dir)
5928 {
5929 struct block *b0, *b1, *tmp;
5930
5931 /* ip6 proto 'proto' */
5932 /* XXX - catch the first fragment of a fragmented packet? */
5933 b0 = gen_cmp(cstate, OR_LINKPL, 6, BPF_B, (bpf_int32)proto);
5934
5935 switch (dir) {
5936 case Q_SRC:
5937 b1 = gen_portrangeatom6(cstate, 0, (bpf_int32)port1, (bpf_int32)port2);
5938 break;
5939
5940 case Q_DST:
5941 b1 = gen_portrangeatom6(cstate, 2, (bpf_int32)port1, (bpf_int32)port2);
5942 break;
5943
5944 case Q_AND:
5945 tmp = gen_portrangeatom6(cstate, 0, (bpf_int32)port1, (bpf_int32)port2);
5946 b1 = gen_portrangeatom6(cstate, 2, (bpf_int32)port1, (bpf_int32)port2);
5947 gen_and(tmp, b1);
5948 break;
5949
5950 case Q_DEFAULT:
5951 case Q_OR:
5952 tmp = gen_portrangeatom6(cstate, 0, (bpf_int32)port1, (bpf_int32)port2);
5953 b1 = gen_portrangeatom6(cstate, 2, (bpf_int32)port1, (bpf_int32)port2);
5954 gen_or(tmp, b1);
5955 break;
5956
5957 default:
5958 abort();
5959 }
5960 gen_and(b0, b1);
5961
5962 return b1;
5963 }
5964
5965 static struct block *
gen_portrange6(compiler_state_t * cstate,int port1,int port2,int ip_proto,int dir)5966 gen_portrange6(compiler_state_t *cstate, int port1, int port2, int ip_proto,
5967 int dir)
5968 {
5969 struct block *b0, *b1, *tmp;
5970
5971 /* link proto ip6 */
5972 b0 = gen_linktype(cstate, ETHERTYPE_IPV6);
5973
5974 switch (ip_proto) {
5975 case IPPROTO_UDP:
5976 case IPPROTO_TCP:
5977 case IPPROTO_SCTP:
5978 b1 = gen_portrangeop6(cstate, port1, port2, ip_proto, dir);
5979 break;
5980
5981 case PROTO_UNDEF:
5982 tmp = gen_portrangeop6(cstate, port1, port2, IPPROTO_TCP, dir);
5983 b1 = gen_portrangeop6(cstate, port1, port2, IPPROTO_UDP, dir);
5984 gen_or(tmp, b1);
5985 tmp = gen_portrangeop6(cstate, port1, port2, IPPROTO_SCTP, dir);
5986 gen_or(tmp, b1);
5987 break;
5988
5989 default:
5990 abort();
5991 }
5992 gen_and(b0, b1);
5993 return b1;
5994 }
5995
5996 static int
lookup_proto(compiler_state_t * cstate,const char * name,int proto)5997 lookup_proto(compiler_state_t *cstate, const char *name, int proto)
5998 {
5999 register int v;
6000
6001 switch (proto) {
6002
6003 case Q_DEFAULT:
6004 case Q_IP:
6005 case Q_IPV6:
6006 v = pcap_nametoproto(name);
6007 if (v == PROTO_UNDEF)
6008 bpf_error(cstate, "unknown ip proto '%s'", name);
6009 break;
6010
6011 case Q_LINK:
6012 /* XXX should look up h/w protocol type based on cstate->linktype */
6013 v = pcap_nametoeproto(name);
6014 if (v == PROTO_UNDEF) {
6015 v = pcap_nametollc(name);
6016 if (v == PROTO_UNDEF)
6017 bpf_error(cstate, "unknown ether proto '%s'", name);
6018 }
6019 break;
6020
6021 case Q_ISO:
6022 if (strcmp(name, "esis") == 0)
6023 v = ISO9542_ESIS;
6024 else if (strcmp(name, "isis") == 0)
6025 v = ISO10589_ISIS;
6026 else if (strcmp(name, "clnp") == 0)
6027 v = ISO8473_CLNP;
6028 else
6029 bpf_error(cstate, "unknown osi proto '%s'", name);
6030 break;
6031
6032 default:
6033 v = PROTO_UNDEF;
6034 break;
6035 }
6036 return v;
6037 }
6038
6039 #if 0
6040 struct stmt *
6041 gen_joinsp(struct stmt **s, int n)
6042 {
6043 return NULL;
6044 }
6045 #endif
6046
6047 static struct block *
gen_protochain(compiler_state_t * cstate,int v,int proto,int dir)6048 gen_protochain(compiler_state_t *cstate, int v, int proto, int dir)
6049 {
6050 #ifdef NO_PROTOCHAIN
6051 return gen_proto(cstate, v, proto, dir);
6052 #else
6053 struct block *b0, *b;
6054 struct slist *s[100];
6055 int fix2, fix3, fix4, fix5;
6056 int ahcheck, again, end;
6057 int i, max;
6058 int reg2 = alloc_reg(cstate);
6059
6060 memset(s, 0, sizeof(s));
6061 fix3 = fix4 = fix5 = 0;
6062
6063 switch (proto) {
6064 case Q_IP:
6065 case Q_IPV6:
6066 break;
6067 case Q_DEFAULT:
6068 b0 = gen_protochain(cstate, v, Q_IP, dir);
6069 b = gen_protochain(cstate, v, Q_IPV6, dir);
6070 gen_or(b0, b);
6071 return b;
6072 default:
6073 bpf_error(cstate, "bad protocol applied for 'protochain'");
6074 /*NOTREACHED*/
6075 }
6076
6077 /*
6078 * We don't handle variable-length prefixes before the link-layer
6079 * header, or variable-length link-layer headers, here yet.
6080 * We might want to add BPF instructions to do the protochain
6081 * work, to simplify that and, on platforms that have a BPF
6082 * interpreter with the new instructions, let the filtering
6083 * be done in the kernel. (We already require a modified BPF
6084 * engine to do the protochain stuff, to support backward
6085 * branches, and backward branch support is unlikely to appear
6086 * in kernel BPF engines.)
6087 */
6088 if (cstate->off_linkpl.is_variable)
6089 bpf_error(cstate, "'protochain' not supported with variable length headers");
6090
6091 cstate->no_optimize = 1; /* this code is not compatible with optimizer yet */
6092
6093 /*
6094 * s[0] is a dummy entry to protect other BPF insn from damage
6095 * by s[fix] = foo with uninitialized variable "fix". It is somewhat
6096 * hard to find interdependency made by jump table fixup.
6097 */
6098 i = 0;
6099 s[i] = new_stmt(cstate, 0); /*dummy*/
6100 i++;
6101
6102 switch (proto) {
6103 case Q_IP:
6104 b0 = gen_linktype(cstate, ETHERTYPE_IP);
6105
6106 /* A = ip->ip_p */
6107 s[i] = new_stmt(cstate, BPF_LD|BPF_ABS|BPF_B);
6108 s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl + 9;
6109 i++;
6110 /* X = ip->ip_hl << 2 */
6111 s[i] = new_stmt(cstate, BPF_LDX|BPF_MSH|BPF_B);
6112 s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
6113 i++;
6114 break;
6115
6116 case Q_IPV6:
6117 b0 = gen_linktype(cstate, ETHERTYPE_IPV6);
6118
6119 /* A = ip6->ip_nxt */
6120 s[i] = new_stmt(cstate, BPF_LD|BPF_ABS|BPF_B);
6121 s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl + 6;
6122 i++;
6123 /* X = sizeof(struct ip6_hdr) */
6124 s[i] = new_stmt(cstate, BPF_LDX|BPF_IMM);
6125 s[i]->s.k = 40;
6126 i++;
6127 break;
6128
6129 default:
6130 bpf_error(cstate, "unsupported proto to gen_protochain");
6131 /*NOTREACHED*/
6132 }
6133
6134 /* again: if (A == v) goto end; else fall through; */
6135 again = i;
6136 s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K);
6137 s[i]->s.k = v;
6138 s[i]->s.jt = NULL; /*later*/
6139 s[i]->s.jf = NULL; /*update in next stmt*/
6140 fix5 = i;
6141 i++;
6142
6143 #ifndef IPPROTO_NONE
6144 #define IPPROTO_NONE 59
6145 #endif
6146 /* if (A == IPPROTO_NONE) goto end */
6147 s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K);
6148 s[i]->s.jt = NULL; /*later*/
6149 s[i]->s.jf = NULL; /*update in next stmt*/
6150 s[i]->s.k = IPPROTO_NONE;
6151 s[fix5]->s.jf = s[i];
6152 fix2 = i;
6153 i++;
6154
6155 if (proto == Q_IPV6) {
6156 int v6start, v6end, v6advance, j;
6157
6158 v6start = i;
6159 /* if (A == IPPROTO_HOPOPTS) goto v6advance */
6160 s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K);
6161 s[i]->s.jt = NULL; /*later*/
6162 s[i]->s.jf = NULL; /*update in next stmt*/
6163 s[i]->s.k = IPPROTO_HOPOPTS;
6164 s[fix2]->s.jf = s[i];
6165 i++;
6166 /* if (A == IPPROTO_DSTOPTS) goto v6advance */
6167 s[i - 1]->s.jf = s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K);
6168 s[i]->s.jt = NULL; /*later*/
6169 s[i]->s.jf = NULL; /*update in next stmt*/
6170 s[i]->s.k = IPPROTO_DSTOPTS;
6171 i++;
6172 /* if (A == IPPROTO_ROUTING) goto v6advance */
6173 s[i - 1]->s.jf = s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K);
6174 s[i]->s.jt = NULL; /*later*/
6175 s[i]->s.jf = NULL; /*update in next stmt*/
6176 s[i]->s.k = IPPROTO_ROUTING;
6177 i++;
6178 /* if (A == IPPROTO_FRAGMENT) goto v6advance; else goto ahcheck; */
6179 s[i - 1]->s.jf = s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K);
6180 s[i]->s.jt = NULL; /*later*/
6181 s[i]->s.jf = NULL; /*later*/
6182 s[i]->s.k = IPPROTO_FRAGMENT;
6183 fix3 = i;
6184 v6end = i;
6185 i++;
6186
6187 /* v6advance: */
6188 v6advance = i;
6189
6190 /*
6191 * in short,
6192 * A = P[X + packet head];
6193 * X = X + (P[X + packet head + 1] + 1) * 8;
6194 */
6195 /* A = P[X + packet head] */
6196 s[i] = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B);
6197 s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
6198 i++;
6199 /* MEM[reg2] = A */
6200 s[i] = new_stmt(cstate, BPF_ST);
6201 s[i]->s.k = reg2;
6202 i++;
6203 /* A = P[X + packet head + 1]; */
6204 s[i] = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B);
6205 s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl + 1;
6206 i++;
6207 /* A += 1 */
6208 s[i] = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
6209 s[i]->s.k = 1;
6210 i++;
6211 /* A *= 8 */
6212 s[i] = new_stmt(cstate, BPF_ALU|BPF_MUL|BPF_K);
6213 s[i]->s.k = 8;
6214 i++;
6215 /* A += X */
6216 s[i] = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X);
6217 s[i]->s.k = 0;
6218 i++;
6219 /* X = A; */
6220 s[i] = new_stmt(cstate, BPF_MISC|BPF_TAX);
6221 i++;
6222 /* A = MEM[reg2] */
6223 s[i] = new_stmt(cstate, BPF_LD|BPF_MEM);
6224 s[i]->s.k = reg2;
6225 i++;
6226
6227 /* goto again; (must use BPF_JA for backward jump) */
6228 s[i] = new_stmt(cstate, BPF_JMP|BPF_JA);
6229 s[i]->s.k = again - i - 1;
6230 s[i - 1]->s.jf = s[i];
6231 i++;
6232
6233 /* fixup */
6234 for (j = v6start; j <= v6end; j++)
6235 s[j]->s.jt = s[v6advance];
6236 } else {
6237 /* nop */
6238 s[i] = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
6239 s[i]->s.k = 0;
6240 s[fix2]->s.jf = s[i];
6241 i++;
6242 }
6243
6244 /* ahcheck: */
6245 ahcheck = i;
6246 /* if (A == IPPROTO_AH) then fall through; else goto end; */
6247 s[i] = new_stmt(cstate, BPF_JMP|BPF_JEQ|BPF_K);
6248 s[i]->s.jt = NULL; /*later*/
6249 s[i]->s.jf = NULL; /*later*/
6250 s[i]->s.k = IPPROTO_AH;
6251 if (fix3)
6252 s[fix3]->s.jf = s[ahcheck];
6253 fix4 = i;
6254 i++;
6255
6256 /*
6257 * in short,
6258 * A = P[X];
6259 * X = X + (P[X + 1] + 2) * 4;
6260 */
6261 /* A = X */
6262 s[i - 1]->s.jt = s[i] = new_stmt(cstate, BPF_MISC|BPF_TXA);
6263 i++;
6264 /* A = P[X + packet head]; */
6265 s[i] = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B);
6266 s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
6267 i++;
6268 /* MEM[reg2] = A */
6269 s[i] = new_stmt(cstate, BPF_ST);
6270 s[i]->s.k = reg2;
6271 i++;
6272 /* A = X */
6273 s[i - 1]->s.jt = s[i] = new_stmt(cstate, BPF_MISC|BPF_TXA);
6274 i++;
6275 /* A += 1 */
6276 s[i] = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
6277 s[i]->s.k = 1;
6278 i++;
6279 /* X = A */
6280 s[i] = new_stmt(cstate, BPF_MISC|BPF_TAX);
6281 i++;
6282 /* A = P[X + packet head] */
6283 s[i] = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B);
6284 s[i]->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
6285 i++;
6286 /* A += 2 */
6287 s[i] = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
6288 s[i]->s.k = 2;
6289 i++;
6290 /* A *= 4 */
6291 s[i] = new_stmt(cstate, BPF_ALU|BPF_MUL|BPF_K);
6292 s[i]->s.k = 4;
6293 i++;
6294 /* X = A; */
6295 s[i] = new_stmt(cstate, BPF_MISC|BPF_TAX);
6296 i++;
6297 /* A = MEM[reg2] */
6298 s[i] = new_stmt(cstate, BPF_LD|BPF_MEM);
6299 s[i]->s.k = reg2;
6300 i++;
6301
6302 /* goto again; (must use BPF_JA for backward jump) */
6303 s[i] = new_stmt(cstate, BPF_JMP|BPF_JA);
6304 s[i]->s.k = again - i - 1;
6305 i++;
6306
6307 /* end: nop */
6308 end = i;
6309 s[i] = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
6310 s[i]->s.k = 0;
6311 s[fix2]->s.jt = s[end];
6312 s[fix4]->s.jf = s[end];
6313 s[fix5]->s.jt = s[end];
6314 i++;
6315
6316 /*
6317 * make slist chain
6318 */
6319 max = i;
6320 for (i = 0; i < max - 1; i++)
6321 s[i]->next = s[i + 1];
6322 s[max - 1]->next = NULL;
6323
6324 /*
6325 * emit final check
6326 */
6327 b = new_block(cstate, JMP(BPF_JEQ));
6328 b->stmts = s[1]; /*remember, s[0] is dummy*/
6329 b->s.k = v;
6330
6331 free_reg(cstate, reg2);
6332
6333 gen_and(b0, b);
6334 return b;
6335 #endif
6336 }
6337
6338 static struct block *
gen_check_802_11_data_frame(compiler_state_t * cstate)6339 gen_check_802_11_data_frame(compiler_state_t *cstate)
6340 {
6341 struct slist *s;
6342 struct block *b0, *b1;
6343
6344 /*
6345 * A data frame has the 0x08 bit (b3) in the frame control field set
6346 * and the 0x04 bit (b2) clear.
6347 */
6348 s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
6349 b0 = new_block(cstate, JMP(BPF_JSET));
6350 b0->s.k = 0x08;
6351 b0->stmts = s;
6352
6353 s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
6354 b1 = new_block(cstate, JMP(BPF_JSET));
6355 b1->s.k = 0x04;
6356 b1->stmts = s;
6357 gen_not(b1);
6358
6359 gen_and(b1, b0);
6360
6361 return b0;
6362 }
6363
6364 /*
6365 * Generate code that checks whether the packet is a packet for protocol
6366 * <proto> and whether the type field in that protocol's header has
6367 * the value <v>, e.g. if <proto> is Q_IP, it checks whether it's an
6368 * IP packet and checks the protocol number in the IP header against <v>.
6369 *
6370 * If <proto> is Q_DEFAULT, i.e. just "proto" was specified, it checks
6371 * against Q_IP and Q_IPV6.
6372 */
6373 static struct block *
gen_proto(compiler_state_t * cstate,int v,int proto,int dir)6374 gen_proto(compiler_state_t *cstate, int v, int proto, int dir)
6375 {
6376 struct block *b0, *b1;
6377 #ifndef CHASE_CHAIN
6378 struct block *b2;
6379 #endif
6380
6381 if (dir != Q_DEFAULT)
6382 bpf_error(cstate, "direction applied to 'proto'");
6383
6384 switch (proto) {
6385 case Q_DEFAULT:
6386 b0 = gen_proto(cstate, v, Q_IP, dir);
6387 b1 = gen_proto(cstate, v, Q_IPV6, dir);
6388 gen_or(b0, b1);
6389 return b1;
6390
6391 case Q_LINK:
6392 return gen_linktype(cstate, v);
6393
6394 case Q_IP:
6395 /*
6396 * For FDDI, RFC 1188 says that SNAP encapsulation is used,
6397 * not LLC encapsulation with LLCSAP_IP.
6398 *
6399 * For IEEE 802 networks - which includes 802.5 token ring
6400 * (which is what DLT_IEEE802 means) and 802.11 - RFC 1042
6401 * says that SNAP encapsulation is used, not LLC encapsulation
6402 * with LLCSAP_IP.
6403 *
6404 * For LLC-encapsulated ATM/"Classical IP", RFC 1483 and
6405 * RFC 2225 say that SNAP encapsulation is used, not LLC
6406 * encapsulation with LLCSAP_IP.
6407 *
6408 * So we always check for ETHERTYPE_IP.
6409 */
6410 b0 = gen_linktype(cstate, ETHERTYPE_IP);
6411 #ifndef CHASE_CHAIN
6412 b1 = gen_cmp(cstate, OR_LINKPL, 9, BPF_B, (bpf_int32)v);
6413 #else
6414 b1 = gen_protochain(cstate, v, Q_IP);
6415 #endif
6416 gen_and(b0, b1);
6417 return b1;
6418
6419 case Q_ARP:
6420 bpf_error(cstate, "arp does not encapsulate another protocol");
6421 /*NOTREACHED*/
6422
6423 case Q_RARP:
6424 bpf_error(cstate, "rarp does not encapsulate another protocol");
6425 /*NOTREACHED*/
6426
6427 case Q_SCTP:
6428 bpf_error(cstate, "'sctp proto' is bogus");
6429 /*NOTREACHED*/
6430
6431 case Q_TCP:
6432 bpf_error(cstate, "'tcp proto' is bogus");
6433 /*NOTREACHED*/
6434
6435 case Q_UDP:
6436 bpf_error(cstate, "'udp proto' is bogus");
6437 /*NOTREACHED*/
6438
6439 case Q_ICMP:
6440 bpf_error(cstate, "'icmp proto' is bogus");
6441 /*NOTREACHED*/
6442
6443 case Q_IGMP:
6444 bpf_error(cstate, "'igmp proto' is bogus");
6445 /*NOTREACHED*/
6446
6447 case Q_IGRP:
6448 bpf_error(cstate, "'igrp proto' is bogus");
6449 /*NOTREACHED*/
6450
6451 case Q_ATALK:
6452 bpf_error(cstate, "AppleTalk encapsulation is not specifiable");
6453 /*NOTREACHED*/
6454
6455 case Q_DECNET:
6456 bpf_error(cstate, "DECNET encapsulation is not specifiable");
6457 /*NOTREACHED*/
6458
6459 case Q_LAT:
6460 bpf_error(cstate, "LAT does not encapsulate another protocol");
6461 /*NOTREACHED*/
6462
6463 case Q_SCA:
6464 bpf_error(cstate, "SCA does not encapsulate another protocol");
6465 /*NOTREACHED*/
6466
6467 case Q_MOPRC:
6468 bpf_error(cstate, "MOPRC does not encapsulate another protocol");
6469 /*NOTREACHED*/
6470
6471 case Q_MOPDL:
6472 bpf_error(cstate, "MOPDL does not encapsulate another protocol");
6473 /*NOTREACHED*/
6474
6475 case Q_IPV6:
6476 b0 = gen_linktype(cstate, ETHERTYPE_IPV6);
6477 #ifndef CHASE_CHAIN
6478 /*
6479 * Also check for a fragment header before the final
6480 * header.
6481 */
6482 b2 = gen_cmp(cstate, OR_LINKPL, 6, BPF_B, IPPROTO_FRAGMENT);
6483 b1 = gen_cmp(cstate, OR_LINKPL, 40, BPF_B, (bpf_int32)v);
6484 gen_and(b2, b1);
6485 b2 = gen_cmp(cstate, OR_LINKPL, 6, BPF_B, (bpf_int32)v);
6486 gen_or(b2, b1);
6487 #else
6488 b1 = gen_protochain(cstate, v, Q_IPV6);
6489 #endif
6490 gen_and(b0, b1);
6491 return b1;
6492
6493 case Q_ICMPV6:
6494 bpf_error(cstate, "'icmp6 proto' is bogus");
6495 /*NOTREACHED*/
6496
6497 case Q_AH:
6498 bpf_error(cstate, "'ah proto' is bogus");
6499 /*NOTREACHED*/
6500
6501 case Q_ESP:
6502 bpf_error(cstate, "'ah proto' is bogus");
6503 /*NOTREACHED*/
6504
6505 case Q_PIM:
6506 bpf_error(cstate, "'pim proto' is bogus");
6507 /*NOTREACHED*/
6508
6509 case Q_VRRP:
6510 bpf_error(cstate, "'vrrp proto' is bogus");
6511 /*NOTREACHED*/
6512
6513 case Q_AARP:
6514 bpf_error(cstate, "'aarp proto' is bogus");
6515 /*NOTREACHED*/
6516
6517 case Q_ISO:
6518 switch (cstate->linktype) {
6519
6520 case DLT_FRELAY:
6521 /*
6522 * Frame Relay packets typically have an OSI
6523 * NLPID at the beginning; "gen_linktype(cstate, LLCSAP_ISONS)"
6524 * generates code to check for all the OSI
6525 * NLPIDs, so calling it and then adding a check
6526 * for the particular NLPID for which we're
6527 * looking is bogus, as we can just check for
6528 * the NLPID.
6529 *
6530 * What we check for is the NLPID and a frame
6531 * control field value of UI, i.e. 0x03 followed
6532 * by the NLPID.
6533 *
6534 * XXX - assumes a 2-byte Frame Relay header with
6535 * DLCI and flags. What if the address is longer?
6536 *
6537 * XXX - what about SNAP-encapsulated frames?
6538 */
6539 return gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, (0x03<<8) | v);
6540 /*NOTREACHED*/
6541
6542 case DLT_C_HDLC:
6543 /*
6544 * Cisco uses an Ethertype lookalike - for OSI,
6545 * it's 0xfefe.
6546 */
6547 b0 = gen_linktype(cstate, LLCSAP_ISONS<<8 | LLCSAP_ISONS);
6548 /* OSI in C-HDLC is stuffed with a fudge byte */
6549 b1 = gen_cmp(cstate, OR_LINKPL_NOSNAP, 1, BPF_B, (long)v);
6550 gen_and(b0, b1);
6551 return b1;
6552
6553 default:
6554 b0 = gen_linktype(cstate, LLCSAP_ISONS);
6555 b1 = gen_cmp(cstate, OR_LINKPL_NOSNAP, 0, BPF_B, (long)v);
6556 gen_and(b0, b1);
6557 return b1;
6558 }
6559
6560 case Q_ESIS:
6561 bpf_error(cstate, "'esis proto' is bogus");
6562 /*NOTREACHED*/
6563
6564 case Q_ISIS:
6565 b0 = gen_proto(cstate, ISO10589_ISIS, Q_ISO, Q_DEFAULT);
6566 /*
6567 * 4 is the offset of the PDU type relative to the IS-IS
6568 * header.
6569 */
6570 b1 = gen_cmp(cstate, OR_LINKPL_NOSNAP, 4, BPF_B, (long)v);
6571 gen_and(b0, b1);
6572 return b1;
6573
6574 case Q_CLNP:
6575 bpf_error(cstate, "'clnp proto' is not supported");
6576 /*NOTREACHED*/
6577
6578 case Q_STP:
6579 bpf_error(cstate, "'stp proto' is bogus");
6580 /*NOTREACHED*/
6581
6582 case Q_IPX:
6583 bpf_error(cstate, "'ipx proto' is bogus");
6584 /*NOTREACHED*/
6585
6586 case Q_NETBEUI:
6587 bpf_error(cstate, "'netbeui proto' is bogus");
6588 /*NOTREACHED*/
6589
6590 case Q_ISIS_L1:
6591 bpf_error(cstate, "'l1 proto' is bogus");
6592 /*NOTREACHED*/
6593
6594 case Q_ISIS_L2:
6595 bpf_error(cstate, "'l2 proto' is bogus");
6596 /*NOTREACHED*/
6597
6598 case Q_ISIS_IIH:
6599 bpf_error(cstate, "'iih proto' is bogus");
6600 /*NOTREACHED*/
6601
6602 case Q_ISIS_SNP:
6603 bpf_error(cstate, "'snp proto' is bogus");
6604 /*NOTREACHED*/
6605
6606 case Q_ISIS_CSNP:
6607 bpf_error(cstate, "'csnp proto' is bogus");
6608 /*NOTREACHED*/
6609
6610 case Q_ISIS_PSNP:
6611 bpf_error(cstate, "'psnp proto' is bogus");
6612 /*NOTREACHED*/
6613
6614 case Q_ISIS_LSP:
6615 bpf_error(cstate, "'lsp proto' is bogus");
6616 /*NOTREACHED*/
6617
6618 case Q_RADIO:
6619 bpf_error(cstate, "'radio proto' is bogus");
6620 /*NOTREACHED*/
6621
6622 case Q_CARP:
6623 bpf_error(cstate, "'carp proto' is bogus");
6624 /*NOTREACHED*/
6625
6626 default:
6627 abort();
6628 /*NOTREACHED*/
6629 }
6630 /*NOTREACHED*/
6631 }
6632
6633 struct block *
gen_scode(compiler_state_t * cstate,const char * name,struct qual q)6634 gen_scode(compiler_state_t *cstate, const char *name, struct qual q)
6635 {
6636 int proto = q.proto;
6637 int dir = q.dir;
6638 int tproto;
6639 u_char *eaddr;
6640 bpf_u_int32 mask, addr;
6641 struct addrinfo *res, *res0;
6642 struct sockaddr_in *sin4;
6643 #ifdef INET6
6644 int tproto6;
6645 struct sockaddr_in6 *sin6;
6646 struct in6_addr mask128;
6647 #endif /*INET6*/
6648 struct block *b, *tmp;
6649 int port, real_proto;
6650 int port1, port2;
6651
6652 /*
6653 * Catch errors reported by us and routines below us, and return NULL
6654 * on an error.
6655 */
6656 if (setjmp(cstate->top_ctx))
6657 return (NULL);
6658
6659 switch (q.addr) {
6660
6661 case Q_NET:
6662 addr = pcap_nametonetaddr(name);
6663 if (addr == 0)
6664 bpf_error(cstate, "unknown network '%s'", name);
6665 /* Left justify network addr and calculate its network mask */
6666 mask = 0xffffffff;
6667 while (addr && (addr & 0xff000000) == 0) {
6668 addr <<= 8;
6669 mask <<= 8;
6670 }
6671 return gen_host(cstate, addr, mask, proto, dir, q.addr);
6672
6673 case Q_DEFAULT:
6674 case Q_HOST:
6675 if (proto == Q_LINK) {
6676 switch (cstate->linktype) {
6677
6678 case DLT_EN10MB:
6679 case DLT_NETANALYZER:
6680 case DLT_NETANALYZER_TRANSPARENT:
6681 eaddr = pcap_ether_hostton(name);
6682 if (eaddr == NULL)
6683 bpf_error(cstate,
6684 "unknown ether host '%s'", name);
6685 tmp = gen_prevlinkhdr_check(cstate);
6686 b = gen_ehostop(cstate, eaddr, dir);
6687 if (tmp != NULL)
6688 gen_and(tmp, b);
6689 free(eaddr);
6690 return b;
6691
6692 case DLT_FDDI:
6693 eaddr = pcap_ether_hostton(name);
6694 if (eaddr == NULL)
6695 bpf_error(cstate,
6696 "unknown FDDI host '%s'", name);
6697 b = gen_fhostop(cstate, eaddr, dir);
6698 free(eaddr);
6699 return b;
6700
6701 case DLT_IEEE802:
6702 eaddr = pcap_ether_hostton(name);
6703 if (eaddr == NULL)
6704 bpf_error(cstate,
6705 "unknown token ring host '%s'", name);
6706 b = gen_thostop(cstate, eaddr, dir);
6707 free(eaddr);
6708 return b;
6709
6710 case DLT_IEEE802_11:
6711 case DLT_PRISM_HEADER:
6712 case DLT_IEEE802_11_RADIO_AVS:
6713 case DLT_IEEE802_11_RADIO:
6714 case DLT_PPI:
6715 eaddr = pcap_ether_hostton(name);
6716 if (eaddr == NULL)
6717 bpf_error(cstate,
6718 "unknown 802.11 host '%s'", name);
6719 b = gen_wlanhostop(cstate, eaddr, dir);
6720 free(eaddr);
6721 return b;
6722
6723 case DLT_IP_OVER_FC:
6724 eaddr = pcap_ether_hostton(name);
6725 if (eaddr == NULL)
6726 bpf_error(cstate,
6727 "unknown Fibre Channel host '%s'", name);
6728 b = gen_ipfchostop(cstate, eaddr, dir);
6729 free(eaddr);
6730 return b;
6731 }
6732
6733 bpf_error(cstate, "only ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel supports link-level host name");
6734 } else if (proto == Q_DECNET) {
6735 unsigned short dn_addr;
6736
6737 if (!__pcap_nametodnaddr(name, &dn_addr)) {
6738 #ifdef DECNETLIB
6739 bpf_error(cstate, "unknown decnet host name '%s'\n", name);
6740 #else
6741 bpf_error(cstate, "decnet name support not included, '%s' cannot be translated\n",
6742 name);
6743 #endif
6744 }
6745 /*
6746 * I don't think DECNET hosts can be multihomed, so
6747 * there is no need to build up a list of addresses
6748 */
6749 return (gen_host(cstate, dn_addr, 0, proto, dir, q.addr));
6750 } else {
6751 #ifdef INET6
6752 memset(&mask128, 0xff, sizeof(mask128));
6753 #endif
6754 res0 = res = pcap_nametoaddrinfo(name);
6755 if (res == NULL)
6756 bpf_error(cstate, "unknown host '%s'", name);
6757 cstate->ai = res;
6758 b = tmp = NULL;
6759 tproto = proto;
6760 #ifdef INET6
6761 tproto6 = proto;
6762 #endif
6763 if (cstate->off_linktype.constant_part == OFFSET_NOT_SET &&
6764 tproto == Q_DEFAULT) {
6765 tproto = Q_IP;
6766 #ifdef INET6
6767 tproto6 = Q_IPV6;
6768 #endif
6769 }
6770 for (res = res0; res; res = res->ai_next) {
6771 switch (res->ai_family) {
6772 case AF_INET:
6773 #ifdef INET6
6774 if (tproto == Q_IPV6)
6775 continue;
6776 #endif
6777
6778 sin4 = (struct sockaddr_in *)
6779 res->ai_addr;
6780 tmp = gen_host(cstate, ntohl(sin4->sin_addr.s_addr),
6781 0xffffffff, tproto, dir, q.addr);
6782 break;
6783 #ifdef INET6
6784 case AF_INET6:
6785 if (tproto6 == Q_IP)
6786 continue;
6787
6788 sin6 = (struct sockaddr_in6 *)
6789 res->ai_addr;
6790 tmp = gen_host6(cstate, &sin6->sin6_addr,
6791 &mask128, tproto6, dir, q.addr);
6792 break;
6793 #endif
6794 default:
6795 continue;
6796 }
6797 if (b)
6798 gen_or(b, tmp);
6799 b = tmp;
6800 }
6801 cstate->ai = NULL;
6802 freeaddrinfo(res0);
6803 if (b == NULL) {
6804 bpf_error(cstate, "unknown host '%s'%s", name,
6805 (proto == Q_DEFAULT)
6806 ? ""
6807 : " for specified address family");
6808 }
6809 return b;
6810 }
6811
6812 case Q_PORT:
6813 if (proto != Q_DEFAULT &&
6814 proto != Q_UDP && proto != Q_TCP && proto != Q_SCTP)
6815 bpf_error(cstate, "illegal qualifier of 'port'");
6816 if (pcap_nametoport(name, &port, &real_proto) == 0)
6817 bpf_error(cstate, "unknown port '%s'", name);
6818 if (proto == Q_UDP) {
6819 if (real_proto == IPPROTO_TCP)
6820 bpf_error(cstate, "port '%s' is tcp", name);
6821 else if (real_proto == IPPROTO_SCTP)
6822 bpf_error(cstate, "port '%s' is sctp", name);
6823 else
6824 /* override PROTO_UNDEF */
6825 real_proto = IPPROTO_UDP;
6826 }
6827 if (proto == Q_TCP) {
6828 if (real_proto == IPPROTO_UDP)
6829 bpf_error(cstate, "port '%s' is udp", name);
6830
6831 else if (real_proto == IPPROTO_SCTP)
6832 bpf_error(cstate, "port '%s' is sctp", name);
6833 else
6834 /* override PROTO_UNDEF */
6835 real_proto = IPPROTO_TCP;
6836 }
6837 if (proto == Q_SCTP) {
6838 if (real_proto == IPPROTO_UDP)
6839 bpf_error(cstate, "port '%s' is udp", name);
6840
6841 else if (real_proto == IPPROTO_TCP)
6842 bpf_error(cstate, "port '%s' is tcp", name);
6843 else
6844 /* override PROTO_UNDEF */
6845 real_proto = IPPROTO_SCTP;
6846 }
6847 if (port < 0)
6848 bpf_error(cstate, "illegal port number %d < 0", port);
6849 if (port > 65535)
6850 bpf_error(cstate, "illegal port number %d > 65535", port);
6851 b = gen_port(cstate, port, real_proto, dir);
6852 gen_or(gen_port6(cstate, port, real_proto, dir), b);
6853 return b;
6854
6855 case Q_PORTRANGE:
6856 if (proto != Q_DEFAULT &&
6857 proto != Q_UDP && proto != Q_TCP && proto != Q_SCTP)
6858 bpf_error(cstate, "illegal qualifier of 'portrange'");
6859 if (pcap_nametoportrange(name, &port1, &port2, &real_proto) == 0)
6860 bpf_error(cstate, "unknown port in range '%s'", name);
6861 if (proto == Q_UDP) {
6862 if (real_proto == IPPROTO_TCP)
6863 bpf_error(cstate, "port in range '%s' is tcp", name);
6864 else if (real_proto == IPPROTO_SCTP)
6865 bpf_error(cstate, "port in range '%s' is sctp", name);
6866 else
6867 /* override PROTO_UNDEF */
6868 real_proto = IPPROTO_UDP;
6869 }
6870 if (proto == Q_TCP) {
6871 if (real_proto == IPPROTO_UDP)
6872 bpf_error(cstate, "port in range '%s' is udp", name);
6873 else if (real_proto == IPPROTO_SCTP)
6874 bpf_error(cstate, "port in range '%s' is sctp", name);
6875 else
6876 /* override PROTO_UNDEF */
6877 real_proto = IPPROTO_TCP;
6878 }
6879 if (proto == Q_SCTP) {
6880 if (real_proto == IPPROTO_UDP)
6881 bpf_error(cstate, "port in range '%s' is udp", name);
6882 else if (real_proto == IPPROTO_TCP)
6883 bpf_error(cstate, "port in range '%s' is tcp", name);
6884 else
6885 /* override PROTO_UNDEF */
6886 real_proto = IPPROTO_SCTP;
6887 }
6888 if (port1 < 0)
6889 bpf_error(cstate, "illegal port number %d < 0", port1);
6890 if (port1 > 65535)
6891 bpf_error(cstate, "illegal port number %d > 65535", port1);
6892 if (port2 < 0)
6893 bpf_error(cstate, "illegal port number %d < 0", port2);
6894 if (port2 > 65535)
6895 bpf_error(cstate, "illegal port number %d > 65535", port2);
6896
6897 b = gen_portrange(cstate, port1, port2, real_proto, dir);
6898 gen_or(gen_portrange6(cstate, port1, port2, real_proto, dir), b);
6899 return b;
6900
6901 case Q_GATEWAY:
6902 #ifndef INET6
6903 eaddr = pcap_ether_hostton(name);
6904 if (eaddr == NULL)
6905 bpf_error(cstate, "unknown ether host: %s", name);
6906
6907 res = pcap_nametoaddrinfo(name);
6908 cstate->ai = res;
6909 if (res == NULL)
6910 bpf_error(cstate, "unknown host '%s'", name);
6911 b = gen_gateway(cstate, eaddr, res, proto, dir);
6912 cstate->ai = NULL;
6913 freeaddrinfo(res);
6914 if (b == NULL)
6915 bpf_error(cstate, "unknown host '%s'", name);
6916 return b;
6917 #else
6918 bpf_error(cstate, "'gateway' not supported in this configuration");
6919 #endif /*INET6*/
6920
6921 case Q_PROTO:
6922 real_proto = lookup_proto(cstate, name, proto);
6923 if (real_proto >= 0)
6924 return gen_proto(cstate, real_proto, proto, dir);
6925 else
6926 bpf_error(cstate, "unknown protocol: %s", name);
6927
6928 case Q_PROTOCHAIN:
6929 real_proto = lookup_proto(cstate, name, proto);
6930 if (real_proto >= 0)
6931 return gen_protochain(cstate, real_proto, proto, dir);
6932 else
6933 bpf_error(cstate, "unknown protocol: %s", name);
6934
6935 case Q_UNDEF:
6936 syntax(cstate);
6937 /*NOTREACHED*/
6938 }
6939 abort();
6940 /*NOTREACHED*/
6941 }
6942
6943 struct block *
gen_mcode(compiler_state_t * cstate,const char * s1,const char * s2,unsigned int masklen,struct qual q)6944 gen_mcode(compiler_state_t *cstate, const char *s1, const char *s2,
6945 unsigned int masklen, struct qual q)
6946 {
6947 register int nlen, mlen;
6948 bpf_u_int32 n, m;
6949
6950 /*
6951 * Catch errors reported by us and routines below us, and return NULL
6952 * on an error.
6953 */
6954 if (setjmp(cstate->top_ctx))
6955 return (NULL);
6956
6957 nlen = __pcap_atoin(s1, &n);
6958 /* Promote short ipaddr */
6959 n <<= 32 - nlen;
6960
6961 if (s2 != NULL) {
6962 mlen = __pcap_atoin(s2, &m);
6963 /* Promote short ipaddr */
6964 m <<= 32 - mlen;
6965 if ((n & ~m) != 0)
6966 bpf_error(cstate, "non-network bits set in \"%s mask %s\"",
6967 s1, s2);
6968 } else {
6969 /* Convert mask len to mask */
6970 if (masklen > 32)
6971 bpf_error(cstate, "mask length must be <= 32");
6972 if (masklen == 0) {
6973 /*
6974 * X << 32 is not guaranteed by C to be 0; it's
6975 * undefined.
6976 */
6977 m = 0;
6978 } else
6979 m = 0xffffffff << (32 - masklen);
6980 if ((n & ~m) != 0)
6981 bpf_error(cstate, "non-network bits set in \"%s/%d\"",
6982 s1, masklen);
6983 }
6984
6985 switch (q.addr) {
6986
6987 case Q_NET:
6988 return gen_host(cstate, n, m, q.proto, q.dir, q.addr);
6989
6990 default:
6991 bpf_error(cstate, "Mask syntax for networks only");
6992 /*NOTREACHED*/
6993 }
6994 /*NOTREACHED*/
6995 }
6996
6997 struct block *
gen_ncode(compiler_state_t * cstate,const char * s,bpf_u_int32 v,struct qual q)6998 gen_ncode(compiler_state_t *cstate, const char *s, bpf_u_int32 v, struct qual q)
6999 {
7000 bpf_u_int32 mask;
7001 int proto;
7002 int dir;
7003 register int vlen;
7004
7005 /*
7006 * Catch errors reported by us and routines below us, and return NULL
7007 * on an error.
7008 */
7009 if (setjmp(cstate->top_ctx))
7010 return (NULL);
7011
7012 proto = q.proto;
7013 dir = q.dir;
7014 if (s == NULL)
7015 vlen = 32;
7016 else if (q.proto == Q_DECNET) {
7017 vlen = __pcap_atodn(s, &v);
7018 if (vlen == 0)
7019 bpf_error(cstate, "malformed decnet address '%s'", s);
7020 } else
7021 vlen = __pcap_atoin(s, &v);
7022
7023 switch (q.addr) {
7024
7025 case Q_DEFAULT:
7026 case Q_HOST:
7027 case Q_NET:
7028 if (proto == Q_DECNET)
7029 return gen_host(cstate, v, 0, proto, dir, q.addr);
7030 else if (proto == Q_LINK) {
7031 bpf_error(cstate, "illegal link layer address");
7032 } else {
7033 mask = 0xffffffff;
7034 if (s == NULL && q.addr == Q_NET) {
7035 /* Promote short net number */
7036 while (v && (v & 0xff000000) == 0) {
7037 v <<= 8;
7038 mask <<= 8;
7039 }
7040 } else {
7041 /* Promote short ipaddr */
7042 v <<= 32 - vlen;
7043 mask <<= 32 - vlen ;
7044 }
7045 return gen_host(cstate, v, mask, proto, dir, q.addr);
7046 }
7047
7048 case Q_PORT:
7049 if (proto == Q_UDP)
7050 proto = IPPROTO_UDP;
7051 else if (proto == Q_TCP)
7052 proto = IPPROTO_TCP;
7053 else if (proto == Q_SCTP)
7054 proto = IPPROTO_SCTP;
7055 else if (proto == Q_DEFAULT)
7056 proto = PROTO_UNDEF;
7057 else
7058 bpf_error(cstate, "illegal qualifier of 'port'");
7059
7060 if (v > 65535)
7061 bpf_error(cstate, "illegal port number %u > 65535", v);
7062
7063 {
7064 struct block *b;
7065 b = gen_port(cstate, (int)v, proto, dir);
7066 gen_or(gen_port6(cstate, (int)v, proto, dir), b);
7067 return b;
7068 }
7069
7070 case Q_PORTRANGE:
7071 if (proto == Q_UDP)
7072 proto = IPPROTO_UDP;
7073 else if (proto == Q_TCP)
7074 proto = IPPROTO_TCP;
7075 else if (proto == Q_SCTP)
7076 proto = IPPROTO_SCTP;
7077 else if (proto == Q_DEFAULT)
7078 proto = PROTO_UNDEF;
7079 else
7080 bpf_error(cstate, "illegal qualifier of 'portrange'");
7081
7082 if (v > 65535)
7083 bpf_error(cstate, "illegal port number %u > 65535", v);
7084
7085 {
7086 struct block *b;
7087 b = gen_portrange(cstate, (int)v, (int)v, proto, dir);
7088 gen_or(gen_portrange6(cstate, (int)v, (int)v, proto, dir), b);
7089 return b;
7090 }
7091
7092 case Q_GATEWAY:
7093 bpf_error(cstate, "'gateway' requires a name");
7094 /*NOTREACHED*/
7095
7096 case Q_PROTO:
7097 return gen_proto(cstate, (int)v, proto, dir);
7098
7099 case Q_PROTOCHAIN:
7100 return gen_protochain(cstate, (int)v, proto, dir);
7101
7102 case Q_UNDEF:
7103 syntax(cstate);
7104 /*NOTREACHED*/
7105
7106 default:
7107 abort();
7108 /*NOTREACHED*/
7109 }
7110 /*NOTREACHED*/
7111 }
7112
7113 #ifdef INET6
7114 struct block *
gen_mcode6(compiler_state_t * cstate,const char * s1,const char * s2,unsigned int masklen,struct qual q)7115 gen_mcode6(compiler_state_t *cstate, const char *s1, const char *s2,
7116 unsigned int masklen, struct qual q)
7117 {
7118 struct addrinfo *res;
7119 struct in6_addr *addr;
7120 struct in6_addr mask;
7121 struct block *b;
7122 uint32_t *a, *m;
7123
7124 /*
7125 * Catch errors reported by us and routines below us, and return NULL
7126 * on an error.
7127 */
7128 if (setjmp(cstate->top_ctx))
7129 return (NULL);
7130
7131 if (s2)
7132 bpf_error(cstate, "no mask %s supported", s2);
7133
7134 res = pcap_nametoaddrinfo(s1);
7135 if (!res)
7136 bpf_error(cstate, "invalid ip6 address %s", s1);
7137 cstate->ai = res;
7138 if (res->ai_next)
7139 bpf_error(cstate, "%s resolved to multiple address", s1);
7140 addr = &((struct sockaddr_in6 *)res->ai_addr)->sin6_addr;
7141
7142 if (sizeof(mask) * 8 < masklen)
7143 bpf_error(cstate, "mask length must be <= %u", (unsigned int)(sizeof(mask) * 8));
7144 memset(&mask, 0, sizeof(mask));
7145 memset(&mask, 0xff, masklen / 8);
7146 if (masklen % 8) {
7147 mask.s6_addr[masklen / 8] =
7148 (0xff << (8 - masklen % 8)) & 0xff;
7149 }
7150
7151 a = (uint32_t *)addr;
7152 m = (uint32_t *)&mask;
7153 if ((a[0] & ~m[0]) || (a[1] & ~m[1])
7154 || (a[2] & ~m[2]) || (a[3] & ~m[3])) {
7155 bpf_error(cstate, "non-network bits set in \"%s/%d\"", s1, masklen);
7156 }
7157
7158 switch (q.addr) {
7159
7160 case Q_DEFAULT:
7161 case Q_HOST:
7162 if (masklen != 128)
7163 bpf_error(cstate, "Mask syntax for networks only");
7164 /* FALLTHROUGH */
7165
7166 case Q_NET:
7167 b = gen_host6(cstate, addr, &mask, q.proto, q.dir, q.addr);
7168 cstate->ai = NULL;
7169 freeaddrinfo(res);
7170 return b;
7171
7172 default:
7173 bpf_error(cstate, "invalid qualifier against IPv6 address");
7174 /*NOTREACHED*/
7175 }
7176 }
7177 #endif /*INET6*/
7178
7179 struct block *
gen_ecode(compiler_state_t * cstate,const char * s,struct qual q)7180 gen_ecode(compiler_state_t *cstate, const char *s, struct qual q)
7181 {
7182 struct block *b, *tmp;
7183
7184 /*
7185 * Catch errors reported by us and routines below us, and return NULL
7186 * on an error.
7187 */
7188 if (setjmp(cstate->top_ctx))
7189 return (NULL);
7190
7191 if ((q.addr == Q_HOST || q.addr == Q_DEFAULT) && q.proto == Q_LINK) {
7192 cstate->e = pcap_ether_aton(s);
7193 if (cstate->e == NULL)
7194 bpf_error(cstate, "malloc");
7195 switch (cstate->linktype) {
7196 case DLT_EN10MB:
7197 case DLT_NETANALYZER:
7198 case DLT_NETANALYZER_TRANSPARENT:
7199 tmp = gen_prevlinkhdr_check(cstate);
7200 b = gen_ehostop(cstate, cstate->e, (int)q.dir);
7201 if (tmp != NULL)
7202 gen_and(tmp, b);
7203 break;
7204 case DLT_FDDI:
7205 b = gen_fhostop(cstate, cstate->e, (int)q.dir);
7206 break;
7207 case DLT_IEEE802:
7208 b = gen_thostop(cstate, cstate->e, (int)q.dir);
7209 break;
7210 case DLT_IEEE802_11:
7211 case DLT_PRISM_HEADER:
7212 case DLT_IEEE802_11_RADIO_AVS:
7213 case DLT_IEEE802_11_RADIO:
7214 case DLT_PPI:
7215 b = gen_wlanhostop(cstate, cstate->e, (int)q.dir);
7216 break;
7217 case DLT_IP_OVER_FC:
7218 b = gen_ipfchostop(cstate, cstate->e, (int)q.dir);
7219 break;
7220 default:
7221 free(cstate->e);
7222 cstate->e = NULL;
7223 bpf_error(cstate, "ethernet addresses supported only on ethernet/FDDI/token ring/802.11/ATM LANE/Fibre Channel");
7224 /*NOTREACHED*/
7225 }
7226 free(cstate->e);
7227 cstate->e = NULL;
7228 return (b);
7229 }
7230 bpf_error(cstate, "ethernet address used in non-ether expression");
7231 /*NOTREACHED*/
7232 }
7233
7234 void
sappend(struct slist * s0,struct slist * s1)7235 sappend(struct slist *s0, struct slist *s1)
7236 {
7237 /*
7238 * This is definitely not the best way to do this, but the
7239 * lists will rarely get long.
7240 */
7241 while (s0->next)
7242 s0 = s0->next;
7243 s0->next = s1;
7244 }
7245
7246 static struct slist *
xfer_to_x(compiler_state_t * cstate,struct arth * a)7247 xfer_to_x(compiler_state_t *cstate, struct arth *a)
7248 {
7249 struct slist *s;
7250
7251 s = new_stmt(cstate, BPF_LDX|BPF_MEM);
7252 s->s.k = a->regno;
7253 return s;
7254 }
7255
7256 static struct slist *
xfer_to_a(compiler_state_t * cstate,struct arth * a)7257 xfer_to_a(compiler_state_t *cstate, struct arth *a)
7258 {
7259 struct slist *s;
7260
7261 s = new_stmt(cstate, BPF_LD|BPF_MEM);
7262 s->s.k = a->regno;
7263 return s;
7264 }
7265
7266 /*
7267 * Modify "index" to use the value stored into its register as an
7268 * offset relative to the beginning of the header for the protocol
7269 * "proto", and allocate a register and put an item "size" bytes long
7270 * (1, 2, or 4) at that offset into that register, making it the register
7271 * for "index".
7272 */
7273 static struct arth *
gen_load_internal(compiler_state_t * cstate,int proto,struct arth * inst,int size)7274 gen_load_internal(compiler_state_t *cstate, int proto, struct arth *inst, int size)
7275 {
7276 struct slist *s, *tmp;
7277 struct block *b;
7278 int regno = alloc_reg(cstate);
7279
7280 free_reg(cstate, inst->regno);
7281 switch (size) {
7282
7283 default:
7284 bpf_error(cstate, "data size must be 1, 2, or 4");
7285
7286 case 1:
7287 size = BPF_B;
7288 break;
7289
7290 case 2:
7291 size = BPF_H;
7292 break;
7293
7294 case 4:
7295 size = BPF_W;
7296 break;
7297 }
7298 switch (proto) {
7299 default:
7300 bpf_error(cstate, "unsupported index operation");
7301
7302 case Q_RADIO:
7303 /*
7304 * The offset is relative to the beginning of the packet
7305 * data, if we have a radio header. (If we don't, this
7306 * is an error.)
7307 */
7308 if (cstate->linktype != DLT_IEEE802_11_RADIO_AVS &&
7309 cstate->linktype != DLT_IEEE802_11_RADIO &&
7310 cstate->linktype != DLT_PRISM_HEADER)
7311 bpf_error(cstate, "radio information not present in capture");
7312
7313 /*
7314 * Load into the X register the offset computed into the
7315 * register specified by "index".
7316 */
7317 s = xfer_to_x(cstate, inst);
7318
7319 /*
7320 * Load the item at that offset.
7321 */
7322 tmp = new_stmt(cstate, BPF_LD|BPF_IND|size);
7323 sappend(s, tmp);
7324 sappend(inst->s, s);
7325 break;
7326
7327 case Q_LINK:
7328 /*
7329 * The offset is relative to the beginning of
7330 * the link-layer header.
7331 *
7332 * XXX - what about ATM LANE? Should the index be
7333 * relative to the beginning of the AAL5 frame, so
7334 * that 0 refers to the beginning of the LE Control
7335 * field, or relative to the beginning of the LAN
7336 * frame, so that 0 refers, for Ethernet LANE, to
7337 * the beginning of the destination address?
7338 */
7339 s = gen_abs_offset_varpart(cstate, &cstate->off_linkhdr);
7340
7341 /*
7342 * If "s" is non-null, it has code to arrange that the
7343 * X register contains the length of the prefix preceding
7344 * the link-layer header. Add to it the offset computed
7345 * into the register specified by "index", and move that
7346 * into the X register. Otherwise, just load into the X
7347 * register the offset computed into the register specified
7348 * by "index".
7349 */
7350 if (s != NULL) {
7351 sappend(s, xfer_to_a(cstate, inst));
7352 sappend(s, new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X));
7353 sappend(s, new_stmt(cstate, BPF_MISC|BPF_TAX));
7354 } else
7355 s = xfer_to_x(cstate, inst);
7356
7357 /*
7358 * Load the item at the sum of the offset we've put in the
7359 * X register and the offset of the start of the link
7360 * layer header (which is 0 if the radio header is
7361 * variable-length; that header length is what we put
7362 * into the X register and then added to the index).
7363 */
7364 tmp = new_stmt(cstate, BPF_LD|BPF_IND|size);
7365 tmp->s.k = cstate->off_linkhdr.constant_part;
7366 sappend(s, tmp);
7367 sappend(inst->s, s);
7368 break;
7369
7370 case Q_IP:
7371 case Q_ARP:
7372 case Q_RARP:
7373 case Q_ATALK:
7374 case Q_DECNET:
7375 case Q_SCA:
7376 case Q_LAT:
7377 case Q_MOPRC:
7378 case Q_MOPDL:
7379 case Q_IPV6:
7380 /*
7381 * The offset is relative to the beginning of
7382 * the network-layer header.
7383 * XXX - are there any cases where we want
7384 * cstate->off_nl_nosnap?
7385 */
7386 s = gen_abs_offset_varpart(cstate, &cstate->off_linkpl);
7387
7388 /*
7389 * If "s" is non-null, it has code to arrange that the
7390 * X register contains the variable part of the offset
7391 * of the link-layer payload. Add to it the offset
7392 * computed into the register specified by "index",
7393 * and move that into the X register. Otherwise, just
7394 * load into the X register the offset computed into
7395 * the register specified by "index".
7396 */
7397 if (s != NULL) {
7398 sappend(s, xfer_to_a(cstate, inst));
7399 sappend(s, new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X));
7400 sappend(s, new_stmt(cstate, BPF_MISC|BPF_TAX));
7401 } else
7402 s = xfer_to_x(cstate, inst);
7403
7404 /*
7405 * Load the item at the sum of the offset we've put in the
7406 * X register, the offset of the start of the network
7407 * layer header from the beginning of the link-layer
7408 * payload, and the constant part of the offset of the
7409 * start of the link-layer payload.
7410 */
7411 tmp = new_stmt(cstate, BPF_LD|BPF_IND|size);
7412 tmp->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
7413 sappend(s, tmp);
7414 sappend(inst->s, s);
7415
7416 /*
7417 * Do the computation only if the packet contains
7418 * the protocol in question.
7419 */
7420 b = gen_proto_abbrev_internal(cstate, proto);
7421 if (inst->b)
7422 gen_and(inst->b, b);
7423 inst->b = b;
7424 break;
7425
7426 case Q_SCTP:
7427 case Q_TCP:
7428 case Q_UDP:
7429 case Q_ICMP:
7430 case Q_IGMP:
7431 case Q_IGRP:
7432 case Q_PIM:
7433 case Q_VRRP:
7434 case Q_CARP:
7435 /*
7436 * The offset is relative to the beginning of
7437 * the transport-layer header.
7438 *
7439 * Load the X register with the length of the IPv4 header
7440 * (plus the offset of the link-layer header, if it's
7441 * a variable-length header), in bytes.
7442 *
7443 * XXX - are there any cases where we want
7444 * cstate->off_nl_nosnap?
7445 * XXX - we should, if we're built with
7446 * IPv6 support, generate code to load either
7447 * IPv4, IPv6, or both, as appropriate.
7448 */
7449 s = gen_loadx_iphdrlen(cstate);
7450
7451 /*
7452 * The X register now contains the sum of the variable
7453 * part of the offset of the link-layer payload and the
7454 * length of the network-layer header.
7455 *
7456 * Load into the A register the offset relative to
7457 * the beginning of the transport layer header,
7458 * add the X register to that, move that to the
7459 * X register, and load with an offset from the
7460 * X register equal to the sum of the constant part of
7461 * the offset of the link-layer payload and the offset,
7462 * relative to the beginning of the link-layer payload,
7463 * of the network-layer header.
7464 */
7465 sappend(s, xfer_to_a(cstate, inst));
7466 sappend(s, new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X));
7467 sappend(s, new_stmt(cstate, BPF_MISC|BPF_TAX));
7468 sappend(s, tmp = new_stmt(cstate, BPF_LD|BPF_IND|size));
7469 tmp->s.k = cstate->off_linkpl.constant_part + cstate->off_nl;
7470 sappend(inst->s, s);
7471
7472 /*
7473 * Do the computation only if the packet contains
7474 * the protocol in question - which is true only
7475 * if this is an IP datagram and is the first or
7476 * only fragment of that datagram.
7477 */
7478 gen_and(gen_proto_abbrev_internal(cstate, proto), b = gen_ipfrag(cstate));
7479 if (inst->b)
7480 gen_and(inst->b, b);
7481 gen_and(gen_proto_abbrev_internal(cstate, Q_IP), b);
7482 inst->b = b;
7483 break;
7484 case Q_ICMPV6:
7485 /*
7486 * Do the computation only if the packet contains
7487 * the protocol in question.
7488 */
7489 b = gen_proto_abbrev_internal(cstate, Q_IPV6);
7490 if (inst->b) {
7491 gen_and(inst->b, b);
7492 }
7493 inst->b = b;
7494
7495 /*
7496 * Check if we have an icmp6 next header
7497 */
7498 b = gen_cmp(cstate, OR_LINKPL, 6, BPF_B, 58);
7499 if (inst->b) {
7500 gen_and(inst->b, b);
7501 }
7502 inst->b = b;
7503
7504
7505 s = gen_abs_offset_varpart(cstate, &cstate->off_linkpl);
7506 /*
7507 * If "s" is non-null, it has code to arrange that the
7508 * X register contains the variable part of the offset
7509 * of the link-layer payload. Add to it the offset
7510 * computed into the register specified by "index",
7511 * and move that into the X register. Otherwise, just
7512 * load into the X register the offset computed into
7513 * the register specified by "index".
7514 */
7515 if (s != NULL) {
7516 sappend(s, xfer_to_a(cstate, inst));
7517 sappend(s, new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X));
7518 sappend(s, new_stmt(cstate, BPF_MISC|BPF_TAX));
7519 } else {
7520 s = xfer_to_x(cstate, inst);
7521 }
7522
7523 /*
7524 * Load the item at the sum of the offset we've put in the
7525 * X register, the offset of the start of the network
7526 * layer header from the beginning of the link-layer
7527 * payload, and the constant part of the offset of the
7528 * start of the link-layer payload.
7529 */
7530 tmp = new_stmt(cstate, BPF_LD|BPF_IND|size);
7531 tmp->s.k = cstate->off_linkpl.constant_part + cstate->off_nl + 40;
7532
7533 sappend(s, tmp);
7534 sappend(inst->s, s);
7535
7536 break;
7537 }
7538 inst->regno = regno;
7539 s = new_stmt(cstate, BPF_ST);
7540 s->s.k = regno;
7541 sappend(inst->s, s);
7542
7543 return inst;
7544 }
7545
7546 struct arth *
gen_load(compiler_state_t * cstate,int proto,struct arth * inst,int size)7547 gen_load(compiler_state_t *cstate, int proto, struct arth *inst, int size)
7548 {
7549 /*
7550 * Catch errors reported by us and routines below us, and return NULL
7551 * on an error.
7552 */
7553 if (setjmp(cstate->top_ctx))
7554 return (NULL);
7555
7556 return gen_load_internal(cstate, proto, inst, size);
7557 }
7558
7559 static struct block *
gen_relation_internal(compiler_state_t * cstate,int code,struct arth * a0,struct arth * a1,int reversed)7560 gen_relation_internal(compiler_state_t *cstate, int code, struct arth *a0,
7561 struct arth *a1, int reversed)
7562 {
7563 struct slist *s0, *s1, *s2;
7564 struct block *b, *tmp;
7565
7566 s0 = xfer_to_x(cstate, a1);
7567 s1 = xfer_to_a(cstate, a0);
7568 if (code == BPF_JEQ) {
7569 s2 = new_stmt(cstate, BPF_ALU|BPF_SUB|BPF_X);
7570 b = new_block(cstate, JMP(code));
7571 sappend(s1, s2);
7572 }
7573 else
7574 b = new_block(cstate, BPF_JMP|code|BPF_X);
7575 if (reversed)
7576 gen_not(b);
7577
7578 sappend(s0, s1);
7579 sappend(a1->s, s0);
7580 sappend(a0->s, a1->s);
7581
7582 b->stmts = a0->s;
7583
7584 free_reg(cstate, a0->regno);
7585 free_reg(cstate, a1->regno);
7586
7587 /* 'and' together protocol checks */
7588 if (a0->b) {
7589 if (a1->b) {
7590 gen_and(a0->b, tmp = a1->b);
7591 }
7592 else
7593 tmp = a0->b;
7594 } else
7595 tmp = a1->b;
7596
7597 if (tmp)
7598 gen_and(tmp, b);
7599
7600 return b;
7601 }
7602
7603 struct block *
gen_relation(compiler_state_t * cstate,int code,struct arth * a0,struct arth * a1,int reversed)7604 gen_relation(compiler_state_t *cstate, int code, struct arth *a0,
7605 struct arth *a1, int reversed)
7606 {
7607 /*
7608 * Catch errors reported by us and routines below us, and return NULL
7609 * on an error.
7610 */
7611 if (setjmp(cstate->top_ctx))
7612 return (NULL);
7613
7614 return gen_relation_internal(cstate, code, a0, a1, reversed);
7615 }
7616
7617 struct arth *
gen_loadlen(compiler_state_t * cstate)7618 gen_loadlen(compiler_state_t *cstate)
7619 {
7620 int regno;
7621 struct arth *a;
7622 struct slist *s;
7623
7624 /*
7625 * Catch errors reported by us and routines below us, and return NULL
7626 * on an error.
7627 */
7628 if (setjmp(cstate->top_ctx))
7629 return (NULL);
7630
7631 regno = alloc_reg(cstate);
7632 a = (struct arth *)newchunk(cstate, sizeof(*a));
7633 s = new_stmt(cstate, BPF_LD|BPF_LEN);
7634 s->next = new_stmt(cstate, BPF_ST);
7635 s->next->s.k = regno;
7636 a->s = s;
7637 a->regno = regno;
7638
7639 return a;
7640 }
7641
7642 static struct arth *
gen_loadi_internal(compiler_state_t * cstate,int val)7643 gen_loadi_internal(compiler_state_t *cstate, int val)
7644 {
7645 struct arth *a;
7646 struct slist *s;
7647 int reg;
7648
7649 a = (struct arth *)newchunk(cstate, sizeof(*a));
7650
7651 reg = alloc_reg(cstate);
7652
7653 s = new_stmt(cstate, BPF_LD|BPF_IMM);
7654 s->s.k = val;
7655 s->next = new_stmt(cstate, BPF_ST);
7656 s->next->s.k = reg;
7657 a->s = s;
7658 a->regno = reg;
7659
7660 return a;
7661 }
7662
7663 struct arth *
gen_loadi(compiler_state_t * cstate,int val)7664 gen_loadi(compiler_state_t *cstate, int val)
7665 {
7666 /*
7667 * Catch errors reported by us and routines below us, and return NULL
7668 * on an error.
7669 */
7670 if (setjmp(cstate->top_ctx))
7671 return (NULL);
7672
7673 return gen_loadi_internal(cstate, val);
7674 }
7675
7676 /*
7677 * The a_arg dance is to avoid annoying whining by compilers that
7678 * a might be clobbered by longjmp - yeah, it might, but *WHO CARES*?
7679 * It's not *used* after setjmp returns.
7680 */
7681 struct arth *
gen_neg(compiler_state_t * cstate,struct arth * a_arg)7682 gen_neg(compiler_state_t *cstate, struct arth *a_arg)
7683 {
7684 struct arth *a = a_arg;
7685 struct slist *s;
7686
7687 /*
7688 * Catch errors reported by us and routines below us, and return NULL
7689 * on an error.
7690 */
7691 if (setjmp(cstate->top_ctx))
7692 return (NULL);
7693
7694 s = xfer_to_a(cstate, a);
7695 sappend(a->s, s);
7696 s = new_stmt(cstate, BPF_ALU|BPF_NEG);
7697 s->s.k = 0;
7698 sappend(a->s, s);
7699 s = new_stmt(cstate, BPF_ST);
7700 s->s.k = a->regno;
7701 sappend(a->s, s);
7702
7703 return a;
7704 }
7705
7706 /*
7707 * The a0_arg dance is to avoid annoying whining by compilers that
7708 * a0 might be clobbered by longjmp - yeah, it might, but *WHO CARES*?
7709 * It's not *used* after setjmp returns.
7710 */
7711 struct arth *
gen_arth(compiler_state_t * cstate,int code,struct arth * a0_arg,struct arth * a1)7712 gen_arth(compiler_state_t *cstate, int code, struct arth *a0_arg,
7713 struct arth *a1)
7714 {
7715 struct arth *a0 = a0_arg;
7716 struct slist *s0, *s1, *s2;
7717
7718 /*
7719 * Catch errors reported by us and routines below us, and return NULL
7720 * on an error.
7721 */
7722 if (setjmp(cstate->top_ctx))
7723 return (NULL);
7724
7725 /*
7726 * Disallow division by, or modulus by, zero; we do this here
7727 * so that it gets done even if the optimizer is disabled.
7728 *
7729 * Also disallow shifts by a value greater than 31; we do this
7730 * here, for the same reason.
7731 */
7732 if (code == BPF_DIV) {
7733 if (a1->s->s.code == (BPF_LD|BPF_IMM) && a1->s->s.k == 0)
7734 bpf_error(cstate, "division by zero");
7735 } else if (code == BPF_MOD) {
7736 if (a1->s->s.code == (BPF_LD|BPF_IMM) && a1->s->s.k == 0)
7737 bpf_error(cstate, "modulus by zero");
7738 } else if (code == BPF_LSH || code == BPF_RSH) {
7739 /*
7740 * XXX - we need to make up our minds as to what integers
7741 * are signed and what integers are unsigned in BPF programs
7742 * and in our IR.
7743 */
7744 if (a1->s->s.code == (BPF_LD|BPF_IMM) &&
7745 (a1->s->s.k < 0 || a1->s->s.k > 31))
7746 bpf_error(cstate, "shift by more than 31 bits");
7747 }
7748 s0 = xfer_to_x(cstate, a1);
7749 s1 = xfer_to_a(cstate, a0);
7750 s2 = new_stmt(cstate, BPF_ALU|BPF_X|code);
7751
7752 sappend(s1, s2);
7753 sappend(s0, s1);
7754 sappend(a1->s, s0);
7755 sappend(a0->s, a1->s);
7756
7757 free_reg(cstate, a0->regno);
7758 free_reg(cstate, a1->regno);
7759
7760 s0 = new_stmt(cstate, BPF_ST);
7761 a0->regno = s0->s.k = alloc_reg(cstate);
7762 sappend(a0->s, s0);
7763
7764 return a0;
7765 }
7766
7767 /*
7768 * Initialize the table of used registers and the current register.
7769 */
7770 static void
init_regs(compiler_state_t * cstate)7771 init_regs(compiler_state_t *cstate)
7772 {
7773 cstate->curreg = 0;
7774 memset(cstate->regused, 0, sizeof cstate->regused);
7775 }
7776
7777 /*
7778 * Return the next free register.
7779 */
7780 static int
alloc_reg(compiler_state_t * cstate)7781 alloc_reg(compiler_state_t *cstate)
7782 {
7783 int n = BPF_MEMWORDS;
7784
7785 while (--n >= 0) {
7786 if (cstate->regused[cstate->curreg])
7787 cstate->curreg = (cstate->curreg + 1) % BPF_MEMWORDS;
7788 else {
7789 cstate->regused[cstate->curreg] = 1;
7790 return cstate->curreg;
7791 }
7792 }
7793 bpf_error(cstate, "too many registers needed to evaluate expression");
7794 /*NOTREACHED*/
7795 }
7796
7797 /*
7798 * Return a register to the table so it can
7799 * be used later.
7800 */
7801 static void
free_reg(compiler_state_t * cstate,int n)7802 free_reg(compiler_state_t *cstate, int n)
7803 {
7804 cstate->regused[n] = 0;
7805 }
7806
7807 static struct block *
gen_len(compiler_state_t * cstate,int jmp,int n)7808 gen_len(compiler_state_t *cstate, int jmp, int n)
7809 {
7810 struct slist *s;
7811 struct block *b;
7812
7813 s = new_stmt(cstate, BPF_LD|BPF_LEN);
7814 b = new_block(cstate, JMP(jmp));
7815 b->stmts = s;
7816 b->s.k = n;
7817
7818 return b;
7819 }
7820
7821 struct block *
gen_greater(compiler_state_t * cstate,int n)7822 gen_greater(compiler_state_t *cstate, int n)
7823 {
7824 /*
7825 * Catch errors reported by us and routines below us, and return NULL
7826 * on an error.
7827 */
7828 if (setjmp(cstate->top_ctx))
7829 return (NULL);
7830
7831 return gen_len(cstate, BPF_JGE, n);
7832 }
7833
7834 /*
7835 * Actually, this is less than or equal.
7836 */
7837 struct block *
gen_less(compiler_state_t * cstate,int n)7838 gen_less(compiler_state_t *cstate, int n)
7839 {
7840 struct block *b;
7841
7842 /*
7843 * Catch errors reported by us and routines below us, and return NULL
7844 * on an error.
7845 */
7846 if (setjmp(cstate->top_ctx))
7847 return (NULL);
7848
7849 b = gen_len(cstate, BPF_JGT, n);
7850 gen_not(b);
7851
7852 return b;
7853 }
7854
7855 /*
7856 * This is for "byte {idx} {op} {val}"; "idx" is treated as relative to
7857 * the beginning of the link-layer header.
7858 * XXX - that means you can't test values in the radiotap header, but
7859 * as that header is difficult if not impossible to parse generally
7860 * without a loop, that might not be a severe problem. A new keyword
7861 * "radio" could be added for that, although what you'd really want
7862 * would be a way of testing particular radio header values, which
7863 * would generate code appropriate to the radio header in question.
7864 */
7865 struct block *
gen_byteop(compiler_state_t * cstate,int op,int idx,int val)7866 gen_byteop(compiler_state_t *cstate, int op, int idx, int val)
7867 {
7868 struct block *b;
7869 struct slist *s;
7870
7871 /*
7872 * Catch errors reported by us and routines below us, and return NULL
7873 * on an error.
7874 */
7875 if (setjmp(cstate->top_ctx))
7876 return (NULL);
7877
7878 switch (op) {
7879 default:
7880 abort();
7881
7882 case '=':
7883 return gen_cmp(cstate, OR_LINKHDR, (u_int)idx, BPF_B, (bpf_int32)val);
7884
7885 case '<':
7886 b = gen_cmp_lt(cstate, OR_LINKHDR, (u_int)idx, BPF_B, (bpf_int32)val);
7887 return b;
7888
7889 case '>':
7890 b = gen_cmp_gt(cstate, OR_LINKHDR, (u_int)idx, BPF_B, (bpf_int32)val);
7891 return b;
7892
7893 case '|':
7894 s = new_stmt(cstate, BPF_ALU|BPF_OR|BPF_K);
7895 break;
7896
7897 case '&':
7898 s = new_stmt(cstate, BPF_ALU|BPF_AND|BPF_K);
7899 break;
7900 }
7901 s->s.k = val;
7902 b = new_block(cstate, JMP(BPF_JEQ));
7903 b->stmts = s;
7904 gen_not(b);
7905
7906 return b;
7907 }
7908
7909 static const u_char abroadcast[] = { 0x0 };
7910
7911 struct block *
gen_broadcast(compiler_state_t * cstate,int proto)7912 gen_broadcast(compiler_state_t *cstate, int proto)
7913 {
7914 bpf_u_int32 hostmask;
7915 struct block *b0, *b1, *b2;
7916 static const u_char ebroadcast[] = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
7917
7918 /*
7919 * Catch errors reported by us and routines below us, and return NULL
7920 * on an error.
7921 */
7922 if (setjmp(cstate->top_ctx))
7923 return (NULL);
7924
7925 switch (proto) {
7926
7927 case Q_DEFAULT:
7928 case Q_LINK:
7929 switch (cstate->linktype) {
7930 case DLT_ARCNET:
7931 case DLT_ARCNET_LINUX:
7932 return gen_ahostop(cstate, abroadcast, Q_DST);
7933 case DLT_EN10MB:
7934 case DLT_NETANALYZER:
7935 case DLT_NETANALYZER_TRANSPARENT:
7936 b1 = gen_prevlinkhdr_check(cstate);
7937 b0 = gen_ehostop(cstate, ebroadcast, Q_DST);
7938 if (b1 != NULL)
7939 gen_and(b1, b0);
7940 return b0;
7941 case DLT_FDDI:
7942 return gen_fhostop(cstate, ebroadcast, Q_DST);
7943 case DLT_IEEE802:
7944 return gen_thostop(cstate, ebroadcast, Q_DST);
7945 case DLT_IEEE802_11:
7946 case DLT_PRISM_HEADER:
7947 case DLT_IEEE802_11_RADIO_AVS:
7948 case DLT_IEEE802_11_RADIO:
7949 case DLT_PPI:
7950 return gen_wlanhostop(cstate, ebroadcast, Q_DST);
7951 case DLT_IP_OVER_FC:
7952 return gen_ipfchostop(cstate, ebroadcast, Q_DST);
7953 default:
7954 bpf_error(cstate, "not a broadcast link");
7955 }
7956 /*NOTREACHED*/
7957
7958 case Q_IP:
7959 /*
7960 * We treat a netmask of PCAP_NETMASK_UNKNOWN (0xffffffff)
7961 * as an indication that we don't know the netmask, and fail
7962 * in that case.
7963 */
7964 if (cstate->netmask == PCAP_NETMASK_UNKNOWN)
7965 bpf_error(cstate, "netmask not known, so 'ip broadcast' not supported");
7966 b0 = gen_linktype(cstate, ETHERTYPE_IP);
7967 hostmask = ~cstate->netmask;
7968 b1 = gen_mcmp(cstate, OR_LINKPL, 16, BPF_W, (bpf_int32)0, hostmask);
7969 b2 = gen_mcmp(cstate, OR_LINKPL, 16, BPF_W,
7970 (bpf_int32)(~0 & hostmask), hostmask);
7971 gen_or(b1, b2);
7972 gen_and(b0, b2);
7973 return b2;
7974 }
7975 bpf_error(cstate, "only link-layer/IP broadcast filters supported");
7976 /*NOTREACHED*/
7977 }
7978
7979 /*
7980 * Generate code to test the low-order bit of a MAC address (that's
7981 * the bottom bit of the *first* byte).
7982 */
7983 static struct block *
gen_mac_multicast(compiler_state_t * cstate,int offset)7984 gen_mac_multicast(compiler_state_t *cstate, int offset)
7985 {
7986 register struct block *b0;
7987 register struct slist *s;
7988
7989 /* link[offset] & 1 != 0 */
7990 s = gen_load_a(cstate, OR_LINKHDR, offset, BPF_B);
7991 b0 = new_block(cstate, JMP(BPF_JSET));
7992 b0->s.k = 1;
7993 b0->stmts = s;
7994 return b0;
7995 }
7996
7997 struct block *
gen_multicast(compiler_state_t * cstate,int proto)7998 gen_multicast(compiler_state_t *cstate, int proto)
7999 {
8000 register struct block *b0, *b1, *b2;
8001 register struct slist *s;
8002
8003 /*
8004 * Catch errors reported by us and routines below us, and return NULL
8005 * on an error.
8006 */
8007 if (setjmp(cstate->top_ctx))
8008 return (NULL);
8009
8010 switch (proto) {
8011
8012 case Q_DEFAULT:
8013 case Q_LINK:
8014 switch (cstate->linktype) {
8015 case DLT_ARCNET:
8016 case DLT_ARCNET_LINUX:
8017 /* all ARCnet multicasts use the same address */
8018 return gen_ahostop(cstate, abroadcast, Q_DST);
8019 case DLT_EN10MB:
8020 case DLT_NETANALYZER:
8021 case DLT_NETANALYZER_TRANSPARENT:
8022 b1 = gen_prevlinkhdr_check(cstate);
8023 /* ether[0] & 1 != 0 */
8024 b0 = gen_mac_multicast(cstate, 0);
8025 if (b1 != NULL)
8026 gen_and(b1, b0);
8027 return b0;
8028 case DLT_FDDI:
8029 /*
8030 * XXX TEST THIS: MIGHT NOT PORT PROPERLY XXX
8031 *
8032 * XXX - was that referring to bit-order issues?
8033 */
8034 /* fddi[1] & 1 != 0 */
8035 return gen_mac_multicast(cstate, 1);
8036 case DLT_IEEE802:
8037 /* tr[2] & 1 != 0 */
8038 return gen_mac_multicast(cstate, 2);
8039 case DLT_IEEE802_11:
8040 case DLT_PRISM_HEADER:
8041 case DLT_IEEE802_11_RADIO_AVS:
8042 case DLT_IEEE802_11_RADIO:
8043 case DLT_PPI:
8044 /*
8045 * Oh, yuk.
8046 *
8047 * For control frames, there is no DA.
8048 *
8049 * For management frames, DA is at an
8050 * offset of 4 from the beginning of
8051 * the packet.
8052 *
8053 * For data frames, DA is at an offset
8054 * of 4 from the beginning of the packet
8055 * if To DS is clear and at an offset of
8056 * 16 from the beginning of the packet
8057 * if To DS is set.
8058 */
8059
8060 /*
8061 * Generate the tests to be done for data frames.
8062 *
8063 * First, check for To DS set, i.e. "link[1] & 0x01".
8064 */
8065 s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
8066 b1 = new_block(cstate, JMP(BPF_JSET));
8067 b1->s.k = 0x01; /* To DS */
8068 b1->stmts = s;
8069
8070 /*
8071 * If To DS is set, the DA is at 16.
8072 */
8073 b0 = gen_mac_multicast(cstate, 16);
8074 gen_and(b1, b0);
8075
8076 /*
8077 * Now, check for To DS not set, i.e. check
8078 * "!(link[1] & 0x01)".
8079 */
8080 s = gen_load_a(cstate, OR_LINKHDR, 1, BPF_B);
8081 b2 = new_block(cstate, JMP(BPF_JSET));
8082 b2->s.k = 0x01; /* To DS */
8083 b2->stmts = s;
8084 gen_not(b2);
8085
8086 /*
8087 * If To DS is not set, the DA is at 4.
8088 */
8089 b1 = gen_mac_multicast(cstate, 4);
8090 gen_and(b2, b1);
8091
8092 /*
8093 * Now OR together the last two checks. That gives
8094 * the complete set of checks for data frames.
8095 */
8096 gen_or(b1, b0);
8097
8098 /*
8099 * Now check for a data frame.
8100 * I.e, check "link[0] & 0x08".
8101 */
8102 s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
8103 b1 = new_block(cstate, JMP(BPF_JSET));
8104 b1->s.k = 0x08;
8105 b1->stmts = s;
8106
8107 /*
8108 * AND that with the checks done for data frames.
8109 */
8110 gen_and(b1, b0);
8111
8112 /*
8113 * If the high-order bit of the type value is 0, this
8114 * is a management frame.
8115 * I.e, check "!(link[0] & 0x08)".
8116 */
8117 s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
8118 b2 = new_block(cstate, JMP(BPF_JSET));
8119 b2->s.k = 0x08;
8120 b2->stmts = s;
8121 gen_not(b2);
8122
8123 /*
8124 * For management frames, the DA is at 4.
8125 */
8126 b1 = gen_mac_multicast(cstate, 4);
8127 gen_and(b2, b1);
8128
8129 /*
8130 * OR that with the checks done for data frames.
8131 * That gives the checks done for management and
8132 * data frames.
8133 */
8134 gen_or(b1, b0);
8135
8136 /*
8137 * If the low-order bit of the type value is 1,
8138 * this is either a control frame or a frame
8139 * with a reserved type, and thus not a
8140 * frame with an SA.
8141 *
8142 * I.e., check "!(link[0] & 0x04)".
8143 */
8144 s = gen_load_a(cstate, OR_LINKHDR, 0, BPF_B);
8145 b1 = new_block(cstate, JMP(BPF_JSET));
8146 b1->s.k = 0x04;
8147 b1->stmts = s;
8148 gen_not(b1);
8149
8150 /*
8151 * AND that with the checks for data and management
8152 * frames.
8153 */
8154 gen_and(b1, b0);
8155 return b0;
8156 case DLT_IP_OVER_FC:
8157 b0 = gen_mac_multicast(cstate, 2);
8158 return b0;
8159 default:
8160 break;
8161 }
8162 /* Link not known to support multicasts */
8163 break;
8164
8165 case Q_IP:
8166 b0 = gen_linktype(cstate, ETHERTYPE_IP);
8167 b1 = gen_cmp_ge(cstate, OR_LINKPL, 16, BPF_B, (bpf_int32)224);
8168 gen_and(b0, b1);
8169 return b1;
8170
8171 case Q_IPV6:
8172 b0 = gen_linktype(cstate, ETHERTYPE_IPV6);
8173 b1 = gen_cmp(cstate, OR_LINKPL, 24, BPF_B, (bpf_int32)255);
8174 gen_and(b0, b1);
8175 return b1;
8176 }
8177 bpf_error(cstate, "link-layer multicast filters supported only on ethernet/FDDI/token ring/ARCNET/802.11/ATM LANE/Fibre Channel");
8178 /*NOTREACHED*/
8179 }
8180
8181 /*
8182 * Filter on inbound (dir == 0) or outbound (dir == 1) traffic.
8183 * Outbound traffic is sent by this machine, while inbound traffic is
8184 * sent by a remote machine (and may include packets destined for a
8185 * unicast or multicast link-layer address we are not subscribing to).
8186 * These are the same definitions implemented by pcap_setdirection().
8187 * Capturing only unicast traffic destined for this host is probably
8188 * better accomplished using a higher-layer filter.
8189 */
8190 struct block *
gen_inbound(compiler_state_t * cstate,int dir)8191 gen_inbound(compiler_state_t *cstate, int dir)
8192 {
8193 register struct block *b0;
8194
8195 /*
8196 * Catch errors reported by us and routines below us, and return NULL
8197 * on an error.
8198 */
8199 if (setjmp(cstate->top_ctx))
8200 return (NULL);
8201
8202 /*
8203 * Only some data link types support inbound/outbound qualifiers.
8204 */
8205 switch (cstate->linktype) {
8206 case DLT_SLIP:
8207 b0 = gen_relation_internal(cstate, BPF_JEQ,
8208 gen_load_internal(cstate, Q_LINK, gen_loadi_internal(cstate, 0), 1),
8209 gen_loadi_internal(cstate, 0),
8210 dir);
8211 break;
8212
8213 case DLT_IPNET:
8214 if (dir) {
8215 /* match outgoing packets */
8216 b0 = gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, IPNET_OUTBOUND);
8217 } else {
8218 /* match incoming packets */
8219 b0 = gen_cmp(cstate, OR_LINKHDR, 2, BPF_H, IPNET_INBOUND);
8220 }
8221 break;
8222
8223 case DLT_LINUX_SLL:
8224 /* match outgoing packets */
8225 b0 = gen_cmp(cstate, OR_LINKHDR, 0, BPF_H, LINUX_SLL_OUTGOING);
8226 if (!dir) {
8227 /* to filter on inbound traffic, invert the match */
8228 gen_not(b0);
8229 }
8230 break;
8231
8232 case DLT_LINUX_SLL2:
8233 /* match outgoing packets */
8234 b0 = gen_cmp(cstate, OR_LINKHDR, 10, BPF_B, LINUX_SLL_OUTGOING);
8235 if (!dir) {
8236 /* to filter on inbound traffic, invert the match */
8237 gen_not(b0);
8238 }
8239 break;
8240
8241 #ifdef HAVE_NET_PFVAR_H
8242 case DLT_PFLOG:
8243 b0 = gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, dir), BPF_B,
8244 (bpf_int32)((dir == 0) ? PF_IN : PF_OUT));
8245 break;
8246 #endif
8247
8248 case DLT_PPP_PPPD:
8249 if (dir) {
8250 /* match outgoing packets */
8251 b0 = gen_cmp(cstate, OR_LINKHDR, 0, BPF_B, PPP_PPPD_OUT);
8252 } else {
8253 /* match incoming packets */
8254 b0 = gen_cmp(cstate, OR_LINKHDR, 0, BPF_B, PPP_PPPD_IN);
8255 }
8256 break;
8257
8258 case DLT_JUNIPER_MFR:
8259 case DLT_JUNIPER_MLFR:
8260 case DLT_JUNIPER_MLPPP:
8261 case DLT_JUNIPER_ATM1:
8262 case DLT_JUNIPER_ATM2:
8263 case DLT_JUNIPER_PPPOE:
8264 case DLT_JUNIPER_PPPOE_ATM:
8265 case DLT_JUNIPER_GGSN:
8266 case DLT_JUNIPER_ES:
8267 case DLT_JUNIPER_MONITOR:
8268 case DLT_JUNIPER_SERVICES:
8269 case DLT_JUNIPER_ETHER:
8270 case DLT_JUNIPER_PPP:
8271 case DLT_JUNIPER_FRELAY:
8272 case DLT_JUNIPER_CHDLC:
8273 case DLT_JUNIPER_VP:
8274 case DLT_JUNIPER_ST:
8275 case DLT_JUNIPER_ISM:
8276 case DLT_JUNIPER_VS:
8277 case DLT_JUNIPER_SRX_E2E:
8278 case DLT_JUNIPER_FIBRECHANNEL:
8279 case DLT_JUNIPER_ATM_CEMIC:
8280
8281 /* juniper flags (including direction) are stored
8282 * the byte after the 3-byte magic number */
8283 if (dir) {
8284 /* match outgoing packets */
8285 b0 = gen_mcmp(cstate, OR_LINKHDR, 3, BPF_B, 0, 0x01);
8286 } else {
8287 /* match incoming packets */
8288 b0 = gen_mcmp(cstate, OR_LINKHDR, 3, BPF_B, 1, 0x01);
8289 }
8290 break;
8291
8292 default:
8293 /*
8294 * If we have packet meta-data indicating a direction,
8295 * and that metadata can be checked by BPF code, check
8296 * it. Otherwise, give up, as this link-layer type has
8297 * nothing in the packet data.
8298 *
8299 * Currently, the only platform where a BPF filter can
8300 * check that metadata is Linux with the in-kernel
8301 * BPF interpreter. If other packet capture mechanisms
8302 * and BPF filters also supported this, it would be
8303 * nice. It would be even better if they made that
8304 * metadata available so that we could provide it
8305 * with newer capture APIs, allowing it to be saved
8306 * in pcapng files.
8307 */
8308 #if defined(linux) && defined(PF_PACKET) && defined(SO_ATTACH_FILTER)
8309 /*
8310 * This is Linux with PF_PACKET support.
8311 * If this is a *live* capture, we can look at
8312 * special meta-data in the filter expression;
8313 * if it's a savefile, we can't.
8314 */
8315 if (cstate->bpf_pcap->rfile != NULL) {
8316 /* We have a FILE *, so this is a savefile */
8317 bpf_error(cstate, "inbound/outbound not supported on %s when reading savefiles",
8318 pcap_datalink_val_to_description_or_dlt(cstate->linktype));
8319 b0 = NULL;
8320 /*NOTREACHED*/
8321 }
8322 /* match outgoing packets */
8323 b0 = gen_cmp(cstate, OR_LINKHDR, SKF_AD_OFF + SKF_AD_PKTTYPE, BPF_H,
8324 PACKET_OUTGOING);
8325 if (!dir) {
8326 /* to filter on inbound traffic, invert the match */
8327 gen_not(b0);
8328 }
8329 #else /* defined(linux) && defined(PF_PACKET) && defined(SO_ATTACH_FILTER) */
8330 bpf_error(cstate, "inbound/outbound not supported on %s",
8331 pcap_datalink_val_to_description_or_dlt(cstate->linktype));
8332 /*NOTREACHED*/
8333 #endif /* defined(linux) && defined(PF_PACKET) && defined(SO_ATTACH_FILTER) */
8334 }
8335 return (b0);
8336 }
8337
8338 #ifdef HAVE_NET_PFVAR_H
8339 /* PF firewall log matched interface */
8340 struct block *
gen_pf_ifname(compiler_state_t * cstate,const char * ifname)8341 gen_pf_ifname(compiler_state_t *cstate, const char *ifname)
8342 {
8343 struct block *b0;
8344 u_int len, off;
8345
8346 /*
8347 * Catch errors reported by us and routines below us, and return NULL
8348 * on an error.
8349 */
8350 if (setjmp(cstate->top_ctx))
8351 return (NULL);
8352
8353 if (cstate->linktype != DLT_PFLOG) {
8354 bpf_error(cstate, "ifname supported only on PF linktype");
8355 /*NOTREACHED*/
8356 }
8357 len = sizeof(((struct pfloghdr *)0)->ifname);
8358 off = offsetof(struct pfloghdr, ifname);
8359 if (strlen(ifname) >= len) {
8360 bpf_error(cstate, "ifname interface names can only be %d characters",
8361 len-1);
8362 /*NOTREACHED*/
8363 }
8364 b0 = gen_bcmp(cstate, OR_LINKHDR, off, (u_int)strlen(ifname),
8365 (const u_char *)ifname);
8366 return (b0);
8367 }
8368
8369 /* PF firewall log ruleset name */
8370 struct block *
gen_pf_ruleset(compiler_state_t * cstate,char * ruleset)8371 gen_pf_ruleset(compiler_state_t *cstate, char *ruleset)
8372 {
8373 struct block *b0;
8374
8375 /*
8376 * Catch errors reported by us and routines below us, and return NULL
8377 * on an error.
8378 */
8379 if (setjmp(cstate->top_ctx))
8380 return (NULL);
8381
8382 if (cstate->linktype != DLT_PFLOG) {
8383 bpf_error(cstate, "ruleset supported only on PF linktype");
8384 /*NOTREACHED*/
8385 }
8386
8387 if (strlen(ruleset) >= sizeof(((struct pfloghdr *)0)->ruleset)) {
8388 bpf_error(cstate, "ruleset names can only be %ld characters",
8389 (long)(sizeof(((struct pfloghdr *)0)->ruleset) - 1));
8390 /*NOTREACHED*/
8391 }
8392
8393 b0 = gen_bcmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, ruleset),
8394 (u_int)strlen(ruleset), (const u_char *)ruleset);
8395 return (b0);
8396 }
8397
8398 /* PF firewall log rule number */
8399 struct block *
gen_pf_rnr(compiler_state_t * cstate,int rnr)8400 gen_pf_rnr(compiler_state_t *cstate, int rnr)
8401 {
8402 struct block *b0;
8403
8404 /*
8405 * Catch errors reported by us and routines below us, and return NULL
8406 * on an error.
8407 */
8408 if (setjmp(cstate->top_ctx))
8409 return (NULL);
8410
8411 if (cstate->linktype != DLT_PFLOG) {
8412 bpf_error(cstate, "rnr supported only on PF linktype");
8413 /*NOTREACHED*/
8414 }
8415
8416 b0 = gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, rulenr), BPF_W,
8417 (bpf_int32)rnr);
8418 return (b0);
8419 }
8420
8421 /* PF firewall log sub-rule number */
8422 struct block *
gen_pf_srnr(compiler_state_t * cstate,int srnr)8423 gen_pf_srnr(compiler_state_t *cstate, int srnr)
8424 {
8425 struct block *b0;
8426
8427 /*
8428 * Catch errors reported by us and routines below us, and return NULL
8429 * on an error.
8430 */
8431 if (setjmp(cstate->top_ctx))
8432 return (NULL);
8433
8434 if (cstate->linktype != DLT_PFLOG) {
8435 bpf_error(cstate, "srnr supported only on PF linktype");
8436 /*NOTREACHED*/
8437 }
8438
8439 b0 = gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, subrulenr), BPF_W,
8440 (bpf_int32)srnr);
8441 return (b0);
8442 }
8443
8444 /* PF firewall log reason code */
8445 struct block *
gen_pf_reason(compiler_state_t * cstate,int reason)8446 gen_pf_reason(compiler_state_t *cstate, int reason)
8447 {
8448 struct block *b0;
8449
8450 /*
8451 * Catch errors reported by us and routines below us, and return NULL
8452 * on an error.
8453 */
8454 if (setjmp(cstate->top_ctx))
8455 return (NULL);
8456
8457 if (cstate->linktype != DLT_PFLOG) {
8458 bpf_error(cstate, "reason supported only on PF linktype");
8459 /*NOTREACHED*/
8460 }
8461
8462 b0 = gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, reason), BPF_B,
8463 (bpf_int32)reason);
8464 return (b0);
8465 }
8466
8467 /* PF firewall log action */
8468 struct block *
gen_pf_action(compiler_state_t * cstate,int action)8469 gen_pf_action(compiler_state_t *cstate, int action)
8470 {
8471 struct block *b0;
8472
8473 /*
8474 * Catch errors reported by us and routines below us, and return NULL
8475 * on an error.
8476 */
8477 if (setjmp(cstate->top_ctx))
8478 return (NULL);
8479
8480 if (cstate->linktype != DLT_PFLOG) {
8481 bpf_error(cstate, "action supported only on PF linktype");
8482 /*NOTREACHED*/
8483 }
8484
8485 b0 = gen_cmp(cstate, OR_LINKHDR, offsetof(struct pfloghdr, action), BPF_B,
8486 (bpf_int32)action);
8487 return (b0);
8488 }
8489 #else /* !HAVE_NET_PFVAR_H */
8490 struct block *
gen_pf_ifname(compiler_state_t * cstate,const char * ifname _U_)8491 gen_pf_ifname(compiler_state_t *cstate, const char *ifname _U_)
8492 {
8493 /*
8494 * Catch errors reported by us and routines below us, and return NULL
8495 * on an error.
8496 */
8497 if (setjmp(cstate->top_ctx))
8498 return (NULL);
8499
8500 bpf_error(cstate, "libpcap was compiled without pf support");
8501 /*NOTREACHED*/
8502 }
8503
8504 struct block *
gen_pf_ruleset(compiler_state_t * cstate,char * ruleset _U_)8505 gen_pf_ruleset(compiler_state_t *cstate, char *ruleset _U_)
8506 {
8507 /*
8508 * Catch errors reported by us and routines below us, and return NULL
8509 * on an error.
8510 */
8511 if (setjmp(cstate->top_ctx))
8512 return (NULL);
8513
8514 bpf_error(cstate, "libpcap was compiled on a machine without pf support");
8515 /*NOTREACHED*/
8516 }
8517
8518 struct block *
gen_pf_rnr(compiler_state_t * cstate,int rnr _U_)8519 gen_pf_rnr(compiler_state_t *cstate, int rnr _U_)
8520 {
8521 /*
8522 * Catch errors reported by us and routines below us, and return NULL
8523 * on an error.
8524 */
8525 if (setjmp(cstate->top_ctx))
8526 return (NULL);
8527
8528 bpf_error(cstate, "libpcap was compiled on a machine without pf support");
8529 /*NOTREACHED*/
8530 }
8531
8532 struct block *
gen_pf_srnr(compiler_state_t * cstate,int srnr _U_)8533 gen_pf_srnr(compiler_state_t *cstate, int srnr _U_)
8534 {
8535 /*
8536 * Catch errors reported by us and routines below us, and return NULL
8537 * on an error.
8538 */
8539 if (setjmp(cstate->top_ctx))
8540 return (NULL);
8541
8542 bpf_error(cstate, "libpcap was compiled on a machine without pf support");
8543 /*NOTREACHED*/
8544 }
8545
8546 struct block *
gen_pf_reason(compiler_state_t * cstate,int reason _U_)8547 gen_pf_reason(compiler_state_t *cstate, int reason _U_)
8548 {
8549 /*
8550 * Catch errors reported by us and routines below us, and return NULL
8551 * on an error.
8552 */
8553 if (setjmp(cstate->top_ctx))
8554 return (NULL);
8555
8556 bpf_error(cstate, "libpcap was compiled on a machine without pf support");
8557 /*NOTREACHED*/
8558 }
8559
8560 struct block *
gen_pf_action(compiler_state_t * cstate,int action _U_)8561 gen_pf_action(compiler_state_t *cstate, int action _U_)
8562 {
8563 /*
8564 * Catch errors reported by us and routines below us, and return NULL
8565 * on an error.
8566 */
8567 if (setjmp(cstate->top_ctx))
8568 return (NULL);
8569
8570 bpf_error(cstate, "libpcap was compiled on a machine without pf support");
8571 /*NOTREACHED*/
8572 }
8573 #endif /* HAVE_NET_PFVAR_H */
8574
8575 /* IEEE 802.11 wireless header */
8576 struct block *
gen_p80211_type(compiler_state_t * cstate,int type,int mask)8577 gen_p80211_type(compiler_state_t *cstate, int type, int mask)
8578 {
8579 struct block *b0;
8580
8581 /*
8582 * Catch errors reported by us and routines below us, and return NULL
8583 * on an error.
8584 */
8585 if (setjmp(cstate->top_ctx))
8586 return (NULL);
8587
8588 switch (cstate->linktype) {
8589
8590 case DLT_IEEE802_11:
8591 case DLT_PRISM_HEADER:
8592 case DLT_IEEE802_11_RADIO_AVS:
8593 case DLT_IEEE802_11_RADIO:
8594 b0 = gen_mcmp(cstate, OR_LINKHDR, 0, BPF_B, (bpf_int32)type,
8595 (bpf_int32)mask);
8596 break;
8597
8598 default:
8599 bpf_error(cstate, "802.11 link-layer types supported only on 802.11");
8600 /*NOTREACHED*/
8601 }
8602
8603 return (b0);
8604 }
8605
8606 struct block *
gen_p80211_fcdir(compiler_state_t * cstate,int fcdir)8607 gen_p80211_fcdir(compiler_state_t *cstate, int fcdir)
8608 {
8609 struct block *b0;
8610
8611 /*
8612 * Catch errors reported by us and routines below us, and return NULL
8613 * on an error.
8614 */
8615 if (setjmp(cstate->top_ctx))
8616 return (NULL);
8617
8618 switch (cstate->linktype) {
8619
8620 case DLT_IEEE802_11:
8621 case DLT_PRISM_HEADER:
8622 case DLT_IEEE802_11_RADIO_AVS:
8623 case DLT_IEEE802_11_RADIO:
8624 break;
8625
8626 default:
8627 bpf_error(cstate, "frame direction supported only with 802.11 headers");
8628 /*NOTREACHED*/
8629 }
8630
8631 b0 = gen_mcmp(cstate, OR_LINKHDR, 1, BPF_B, (bpf_int32)fcdir,
8632 (bpf_u_int32)IEEE80211_FC1_DIR_MASK);
8633
8634 return (b0);
8635 }
8636
8637 struct block *
gen_acode(compiler_state_t * cstate,const char * s,struct qual q)8638 gen_acode(compiler_state_t *cstate, const char *s, struct qual q)
8639 {
8640 struct block *b;
8641
8642 /*
8643 * Catch errors reported by us and routines below us, and return NULL
8644 * on an error.
8645 */
8646 if (setjmp(cstate->top_ctx))
8647 return (NULL);
8648
8649 switch (cstate->linktype) {
8650
8651 case DLT_ARCNET:
8652 case DLT_ARCNET_LINUX:
8653 if ((q.addr == Q_HOST || q.addr == Q_DEFAULT) &&
8654 q.proto == Q_LINK) {
8655 cstate->e = pcap_ether_aton(s);
8656 if (cstate->e == NULL)
8657 bpf_error(cstate, "malloc");
8658 b = gen_ahostop(cstate, cstate->e, (int)q.dir);
8659 free(cstate->e);
8660 cstate->e = NULL;
8661 return (b);
8662 } else
8663 bpf_error(cstate, "ARCnet address used in non-arc expression");
8664 /*NOTREACHED*/
8665
8666 default:
8667 bpf_error(cstate, "aid supported only on ARCnet");
8668 /*NOTREACHED*/
8669 }
8670 }
8671
8672 static struct block *
gen_ahostop(compiler_state_t * cstate,const u_char * eaddr,int dir)8673 gen_ahostop(compiler_state_t *cstate, const u_char *eaddr, int dir)
8674 {
8675 register struct block *b0, *b1;
8676
8677 switch (dir) {
8678 /* src comes first, different from Ethernet */
8679 case Q_SRC:
8680 return gen_bcmp(cstate, OR_LINKHDR, 0, 1, eaddr);
8681
8682 case Q_DST:
8683 return gen_bcmp(cstate, OR_LINKHDR, 1, 1, eaddr);
8684
8685 case Q_AND:
8686 b0 = gen_ahostop(cstate, eaddr, Q_SRC);
8687 b1 = gen_ahostop(cstate, eaddr, Q_DST);
8688 gen_and(b0, b1);
8689 return b1;
8690
8691 case Q_DEFAULT:
8692 case Q_OR:
8693 b0 = gen_ahostop(cstate, eaddr, Q_SRC);
8694 b1 = gen_ahostop(cstate, eaddr, Q_DST);
8695 gen_or(b0, b1);
8696 return b1;
8697
8698 case Q_ADDR1:
8699 bpf_error(cstate, "'addr1' and 'address1' are only supported on 802.11");
8700 /*NOTREACHED*/
8701
8702 case Q_ADDR2:
8703 bpf_error(cstate, "'addr2' and 'address2' are only supported on 802.11");
8704 /*NOTREACHED*/
8705
8706 case Q_ADDR3:
8707 bpf_error(cstate, "'addr3' and 'address3' are only supported on 802.11");
8708 /*NOTREACHED*/
8709
8710 case Q_ADDR4:
8711 bpf_error(cstate, "'addr4' and 'address4' are only supported on 802.11");
8712 /*NOTREACHED*/
8713
8714 case Q_RA:
8715 bpf_error(cstate, "'ra' is only supported on 802.11");
8716 /*NOTREACHED*/
8717
8718 case Q_TA:
8719 bpf_error(cstate, "'ta' is only supported on 802.11");
8720 /*NOTREACHED*/
8721 }
8722 abort();
8723 /*NOTREACHED*/
8724 }
8725
8726 static struct block *
gen_vlan_tpid_test(compiler_state_t * cstate)8727 gen_vlan_tpid_test(compiler_state_t *cstate)
8728 {
8729 struct block *b0, *b1;
8730
8731 /* check for VLAN, including QinQ */
8732 b0 = gen_linktype(cstate, ETHERTYPE_8021Q);
8733 b1 = gen_linktype(cstate, ETHERTYPE_8021AD);
8734 gen_or(b0,b1);
8735 b0 = b1;
8736 b1 = gen_linktype(cstate, ETHERTYPE_8021QINQ);
8737 gen_or(b0,b1);
8738
8739 return b1;
8740 }
8741
8742 static struct block *
gen_vlan_vid_test(compiler_state_t * cstate,bpf_u_int32 vlan_num)8743 gen_vlan_vid_test(compiler_state_t *cstate, bpf_u_int32 vlan_num)
8744 {
8745 if (vlan_num > 0x0fff) {
8746 bpf_error(cstate, "VLAN tag %u greater than maximum %u",
8747 vlan_num, 0x0fff);
8748 }
8749 return gen_mcmp(cstate, OR_LINKPL, 0, BPF_H, (bpf_int32)vlan_num, 0x0fff);
8750 }
8751
8752 static struct block *
gen_vlan_no_bpf_extensions(compiler_state_t * cstate,bpf_u_int32 vlan_num,int has_vlan_tag)8753 gen_vlan_no_bpf_extensions(compiler_state_t *cstate, bpf_u_int32 vlan_num,
8754 int has_vlan_tag)
8755 {
8756 struct block *b0, *b1;
8757
8758 b0 = gen_vlan_tpid_test(cstate);
8759
8760 if (has_vlan_tag) {
8761 b1 = gen_vlan_vid_test(cstate, vlan_num);
8762 gen_and(b0, b1);
8763 b0 = b1;
8764 }
8765
8766 /*
8767 * Both payload and link header type follow the VLAN tags so that
8768 * both need to be updated.
8769 */
8770 cstate->off_linkpl.constant_part += 4;
8771 cstate->off_linktype.constant_part += 4;
8772
8773 return b0;
8774 }
8775
8776 #if defined(SKF_AD_VLAN_TAG_PRESENT)
8777 /* add v to variable part of off */
8778 static void
gen_vlan_vloffset_add(compiler_state_t * cstate,bpf_abs_offset * off,int v,struct slist * s)8779 gen_vlan_vloffset_add(compiler_state_t *cstate, bpf_abs_offset *off, int v, struct slist *s)
8780 {
8781 struct slist *s2;
8782
8783 if (!off->is_variable)
8784 off->is_variable = 1;
8785 if (off->reg == -1)
8786 off->reg = alloc_reg(cstate);
8787
8788 s2 = new_stmt(cstate, BPF_LD|BPF_MEM);
8789 s2->s.k = off->reg;
8790 sappend(s, s2);
8791 s2 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_IMM);
8792 s2->s.k = v;
8793 sappend(s, s2);
8794 s2 = new_stmt(cstate, BPF_ST);
8795 s2->s.k = off->reg;
8796 sappend(s, s2);
8797 }
8798
8799 /*
8800 * patch block b_tpid (VLAN TPID test) to update variable parts of link payload
8801 * and link type offsets first
8802 */
8803 static void
gen_vlan_patch_tpid_test(compiler_state_t * cstate,struct block * b_tpid)8804 gen_vlan_patch_tpid_test(compiler_state_t *cstate, struct block *b_tpid)
8805 {
8806 struct slist s;
8807
8808 /* offset determined at run time, shift variable part */
8809 s.next = NULL;
8810 cstate->is_vlan_vloffset = 1;
8811 gen_vlan_vloffset_add(cstate, &cstate->off_linkpl, 4, &s);
8812 gen_vlan_vloffset_add(cstate, &cstate->off_linktype, 4, &s);
8813
8814 /* we get a pointer to a chain of or-ed blocks, patch first of them */
8815 sappend(s.next, b_tpid->head->stmts);
8816 b_tpid->head->stmts = s.next;
8817 }
8818
8819 /*
8820 * patch block b_vid (VLAN id test) to load VID value either from packet
8821 * metadata (using BPF extensions) if SKF_AD_VLAN_TAG_PRESENT is true
8822 */
8823 static void
gen_vlan_patch_vid_test(compiler_state_t * cstate,struct block * b_vid)8824 gen_vlan_patch_vid_test(compiler_state_t *cstate, struct block *b_vid)
8825 {
8826 struct slist *s, *s2, *sjeq;
8827 unsigned cnt;
8828
8829 s = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS);
8830 s->s.k = SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT;
8831
8832 /* true -> next instructions, false -> beginning of b_vid */
8833 sjeq = new_stmt(cstate, JMP(BPF_JEQ));
8834 sjeq->s.k = 1;
8835 sjeq->s.jf = b_vid->stmts;
8836 sappend(s, sjeq);
8837
8838 s2 = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS);
8839 s2->s.k = SKF_AD_OFF + SKF_AD_VLAN_TAG;
8840 sappend(s, s2);
8841 sjeq->s.jt = s2;
8842
8843 /* Jump to the test in b_vid. We need to jump one instruction before
8844 * the end of the b_vid block so that we only skip loading the TCI
8845 * from packet data and not the 'and' instruction extractging VID.
8846 */
8847 cnt = 0;
8848 for (s2 = b_vid->stmts; s2; s2 = s2->next)
8849 cnt++;
8850 s2 = new_stmt(cstate, JMP(BPF_JA));
8851 s2->s.k = cnt - 1;
8852 sappend(s, s2);
8853
8854 /* insert our statements at the beginning of b_vid */
8855 sappend(s, b_vid->stmts);
8856 b_vid->stmts = s;
8857 }
8858
8859 /*
8860 * Generate check for "vlan" or "vlan <id>" on systems with support for BPF
8861 * extensions. Even if kernel supports VLAN BPF extensions, (outermost) VLAN
8862 * tag can be either in metadata or in packet data; therefore if the
8863 * SKF_AD_VLAN_TAG_PRESENT test is negative, we need to check link
8864 * header for VLAN tag. As the decision is done at run time, we need
8865 * update variable part of the offsets
8866 */
8867 static struct block *
gen_vlan_bpf_extensions(compiler_state_t * cstate,bpf_u_int32 vlan_num,int has_vlan_tag)8868 gen_vlan_bpf_extensions(compiler_state_t *cstate, bpf_u_int32 vlan_num,
8869 int has_vlan_tag)
8870 {
8871 struct block *b0, *b_tpid, *b_vid = NULL;
8872 struct slist *s;
8873
8874 /* generate new filter code based on extracting packet
8875 * metadata */
8876 s = new_stmt(cstate, BPF_LD|BPF_B|BPF_ABS);
8877 s->s.k = SKF_AD_OFF + SKF_AD_VLAN_TAG_PRESENT;
8878
8879 b0 = new_block(cstate, JMP(BPF_JEQ));
8880 b0->stmts = s;
8881 b0->s.k = 1;
8882
8883 /*
8884 * This is tricky. We need to insert the statements updating variable
8885 * parts of offsets before the the traditional TPID and VID tests so
8886 * that they are called whenever SKF_AD_VLAN_TAG_PRESENT fails but
8887 * we do not want this update to affect those checks. That's why we
8888 * generate both test blocks first and insert the statements updating
8889 * variable parts of both offsets after that. This wouldn't work if
8890 * there already were variable length link header when entering this
8891 * function but gen_vlan_bpf_extensions() isn't called in that case.
8892 */
8893 b_tpid = gen_vlan_tpid_test(cstate);
8894 if (has_vlan_tag)
8895 b_vid = gen_vlan_vid_test(cstate, vlan_num);
8896
8897 gen_vlan_patch_tpid_test(cstate, b_tpid);
8898 gen_or(b0, b_tpid);
8899 b0 = b_tpid;
8900
8901 if (has_vlan_tag) {
8902 gen_vlan_patch_vid_test(cstate, b_vid);
8903 gen_and(b0, b_vid);
8904 b0 = b_vid;
8905 }
8906
8907 return b0;
8908 }
8909 #endif
8910
8911 /*
8912 * support IEEE 802.1Q VLAN trunk over ethernet
8913 */
8914 struct block *
gen_vlan(compiler_state_t * cstate,bpf_u_int32 vlan_num,int has_vlan_tag)8915 gen_vlan(compiler_state_t *cstate, bpf_u_int32 vlan_num, int has_vlan_tag)
8916 {
8917 struct block *b0;
8918
8919 /*
8920 * Catch errors reported by us and routines below us, and return NULL
8921 * on an error.
8922 */
8923 if (setjmp(cstate->top_ctx))
8924 return (NULL);
8925
8926 /* can't check for VLAN-encapsulated packets inside MPLS */
8927 if (cstate->label_stack_depth > 0)
8928 bpf_error(cstate, "no VLAN match after MPLS");
8929
8930 /*
8931 * Check for a VLAN packet, and then change the offsets to point
8932 * to the type and data fields within the VLAN packet. Just
8933 * increment the offsets, so that we can support a hierarchy, e.g.
8934 * "vlan 300 && vlan 200" to capture VLAN 200 encapsulated within
8935 * VLAN 100.
8936 *
8937 * XXX - this is a bit of a kludge. If we were to split the
8938 * compiler into a parser that parses an expression and
8939 * generates an expression tree, and a code generator that
8940 * takes an expression tree (which could come from our
8941 * parser or from some other parser) and generates BPF code,
8942 * we could perhaps make the offsets parameters of routines
8943 * and, in the handler for an "AND" node, pass to subnodes
8944 * other than the VLAN node the adjusted offsets.
8945 *
8946 * This would mean that "vlan" would, instead of changing the
8947 * behavior of *all* tests after it, change only the behavior
8948 * of tests ANDed with it. That would change the documented
8949 * semantics of "vlan", which might break some expressions.
8950 * However, it would mean that "(vlan and ip) or ip" would check
8951 * both for VLAN-encapsulated IP and IP-over-Ethernet, rather than
8952 * checking only for VLAN-encapsulated IP, so that could still
8953 * be considered worth doing; it wouldn't break expressions
8954 * that are of the form "vlan and ..." or "vlan N and ...",
8955 * which I suspect are the most common expressions involving
8956 * "vlan". "vlan or ..." doesn't necessarily do what the user
8957 * would really want, now, as all the "or ..." tests would
8958 * be done assuming a VLAN, even though the "or" could be viewed
8959 * as meaning "or, if this isn't a VLAN packet...".
8960 */
8961 switch (cstate->linktype) {
8962
8963 case DLT_EN10MB:
8964 case DLT_NETANALYZER:
8965 case DLT_NETANALYZER_TRANSPARENT:
8966 #if defined(SKF_AD_VLAN_TAG_PRESENT)
8967 /* Verify that this is the outer part of the packet and
8968 * not encapsulated somehow. */
8969 if (cstate->vlan_stack_depth == 0 && !cstate->off_linkhdr.is_variable &&
8970 cstate->off_linkhdr.constant_part ==
8971 cstate->off_outermostlinkhdr.constant_part) {
8972 /*
8973 * Do we need special VLAN handling?
8974 */
8975 if (cstate->bpf_pcap->bpf_codegen_flags & BPF_SPECIAL_VLAN_HANDLING)
8976 b0 = gen_vlan_bpf_extensions(cstate, vlan_num,
8977 has_vlan_tag);
8978 else
8979 b0 = gen_vlan_no_bpf_extensions(cstate,
8980 vlan_num, has_vlan_tag);
8981 } else
8982 #endif
8983 b0 = gen_vlan_no_bpf_extensions(cstate, vlan_num,
8984 has_vlan_tag);
8985 break;
8986
8987 case DLT_IEEE802_11:
8988 case DLT_PRISM_HEADER:
8989 case DLT_IEEE802_11_RADIO_AVS:
8990 case DLT_IEEE802_11_RADIO:
8991 b0 = gen_vlan_no_bpf_extensions(cstate, vlan_num, has_vlan_tag);
8992 break;
8993
8994 default:
8995 bpf_error(cstate, "no VLAN support for %s",
8996 pcap_datalink_val_to_description_or_dlt(cstate->linktype));
8997 /*NOTREACHED*/
8998 }
8999
9000 cstate->vlan_stack_depth++;
9001
9002 return (b0);
9003 }
9004
9005 /*
9006 * support for MPLS
9007 *
9008 * The label_num_arg dance is to avoid annoying whining by compilers that
9009 * label_num might be clobbered by longjmp - yeah, it might, but *WHO CARES*?
9010 * It's not *used* after setjmp returns.
9011 */
9012 struct block *
gen_mpls(compiler_state_t * cstate,bpf_u_int32 label_num_arg,int has_label_num)9013 gen_mpls(compiler_state_t *cstate, bpf_u_int32 label_num_arg,
9014 int has_label_num)
9015 {
9016 volatile bpf_u_int32 label_num = label_num_arg;
9017 struct block *b0, *b1;
9018
9019 /*
9020 * Catch errors reported by us and routines below us, and return NULL
9021 * on an error.
9022 */
9023 if (setjmp(cstate->top_ctx))
9024 return (NULL);
9025
9026 if (cstate->label_stack_depth > 0) {
9027 /* just match the bottom-of-stack bit clear */
9028 b0 = gen_mcmp(cstate, OR_PREVMPLSHDR, 2, BPF_B, 0, 0x01);
9029 } else {
9030 /*
9031 * We're not in an MPLS stack yet, so check the link-layer
9032 * type against MPLS.
9033 */
9034 switch (cstate->linktype) {
9035
9036 case DLT_C_HDLC: /* fall through */
9037 case DLT_EN10MB:
9038 case DLT_NETANALYZER:
9039 case DLT_NETANALYZER_TRANSPARENT:
9040 b0 = gen_linktype(cstate, ETHERTYPE_MPLS);
9041 break;
9042
9043 case DLT_PPP:
9044 b0 = gen_linktype(cstate, PPP_MPLS_UCAST);
9045 break;
9046
9047 /* FIXME add other DLT_s ...
9048 * for Frame-Relay/and ATM this may get messy due to SNAP headers
9049 * leave it for now */
9050
9051 default:
9052 bpf_error(cstate, "no MPLS support for %s",
9053 pcap_datalink_val_to_description_or_dlt(cstate->linktype));
9054 /*NOTREACHED*/
9055 }
9056 }
9057
9058 /* If a specific MPLS label is requested, check it */
9059 if (has_label_num) {
9060 if (label_num > 0xFFFFF) {
9061 bpf_error(cstate, "MPLS label %u greater than maximum %u",
9062 label_num, 0xFFFFF);
9063 }
9064 label_num = label_num << 12; /* label is shifted 12 bits on the wire */
9065 b1 = gen_mcmp(cstate, OR_LINKPL, 0, BPF_W, (bpf_int32)label_num,
9066 0xfffff000); /* only compare the first 20 bits */
9067 gen_and(b0, b1);
9068 b0 = b1;
9069 }
9070
9071 /*
9072 * Change the offsets to point to the type and data fields within
9073 * the MPLS packet. Just increment the offsets, so that we
9074 * can support a hierarchy, e.g. "mpls 100000 && mpls 1024" to
9075 * capture packets with an outer label of 100000 and an inner
9076 * label of 1024.
9077 *
9078 * Increment the MPLS stack depth as well; this indicates that
9079 * we're checking MPLS-encapsulated headers, to make sure higher
9080 * level code generators don't try to match against IP-related
9081 * protocols such as Q_ARP, Q_RARP etc.
9082 *
9083 * XXX - this is a bit of a kludge. See comments in gen_vlan().
9084 */
9085 cstate->off_nl_nosnap += 4;
9086 cstate->off_nl += 4;
9087 cstate->label_stack_depth++;
9088 return (b0);
9089 }
9090
9091 /*
9092 * Support PPPOE discovery and session.
9093 */
9094 struct block *
gen_pppoed(compiler_state_t * cstate)9095 gen_pppoed(compiler_state_t *cstate)
9096 {
9097 /*
9098 * Catch errors reported by us and routines below us, and return NULL
9099 * on an error.
9100 */
9101 if (setjmp(cstate->top_ctx))
9102 return (NULL);
9103
9104 /* check for PPPoE discovery */
9105 return gen_linktype(cstate, (bpf_int32)ETHERTYPE_PPPOED);
9106 }
9107
9108 struct block *
gen_pppoes(compiler_state_t * cstate,bpf_u_int32 sess_num,int has_sess_num)9109 gen_pppoes(compiler_state_t *cstate, bpf_u_int32 sess_num, int has_sess_num)
9110 {
9111 struct block *b0, *b1;
9112
9113 /*
9114 * Catch errors reported by us and routines below us, and return NULL
9115 * on an error.
9116 */
9117 if (setjmp(cstate->top_ctx))
9118 return (NULL);
9119
9120 /*
9121 * Test against the PPPoE session link-layer type.
9122 */
9123 b0 = gen_linktype(cstate, (bpf_int32)ETHERTYPE_PPPOES);
9124
9125 /* If a specific session is requested, check PPPoE session id */
9126 if (has_sess_num) {
9127 if (sess_num > 0x0000ffff) {
9128 bpf_error(cstate, "PPPoE session number %u greater than maximum %u",
9129 sess_num, 0x0000ffff);
9130 }
9131 b1 = gen_mcmp(cstate, OR_LINKPL, 0, BPF_W,
9132 (bpf_int32)sess_num, 0x0000ffff);
9133 gen_and(b0, b1);
9134 b0 = b1;
9135 }
9136
9137 /*
9138 * Change the offsets to point to the type and data fields within
9139 * the PPP packet, and note that this is PPPoE rather than
9140 * raw PPP.
9141 *
9142 * XXX - this is a bit of a kludge. See the comments in
9143 * gen_vlan().
9144 *
9145 * The "network-layer" protocol is PPPoE, which has a 6-byte
9146 * PPPoE header, followed by a PPP packet.
9147 *
9148 * There is no HDLC encapsulation for the PPP packet (it's
9149 * encapsulated in PPPoES instead), so the link-layer type
9150 * starts at the first byte of the PPP packet. For PPPoE,
9151 * that offset is relative to the beginning of the total
9152 * link-layer payload, including any 802.2 LLC header, so
9153 * it's 6 bytes past cstate->off_nl.
9154 */
9155 PUSH_LINKHDR(cstate, DLT_PPP, cstate->off_linkpl.is_variable,
9156 cstate->off_linkpl.constant_part + cstate->off_nl + 6, /* 6 bytes past the PPPoE header */
9157 cstate->off_linkpl.reg);
9158
9159 cstate->off_linktype = cstate->off_linkhdr;
9160 cstate->off_linkpl.constant_part = cstate->off_linkhdr.constant_part + 2;
9161
9162 cstate->off_nl = 0;
9163 cstate->off_nl_nosnap = 0; /* no 802.2 LLC */
9164
9165 return b0;
9166 }
9167
9168 /* Check that this is Geneve and the VNI is correct if
9169 * specified. Parameterized to handle both IPv4 and IPv6. */
9170 static struct block *
gen_geneve_check(compiler_state_t * cstate,struct block * (* gen_portfn)(compiler_state_t *,int,int,int),enum e_offrel offrel,bpf_u_int32 vni,int has_vni)9171 gen_geneve_check(compiler_state_t *cstate,
9172 struct block *(*gen_portfn)(compiler_state_t *, int, int, int),
9173 enum e_offrel offrel, bpf_u_int32 vni, int has_vni)
9174 {
9175 struct block *b0, *b1;
9176
9177 b0 = gen_portfn(cstate, GENEVE_PORT, IPPROTO_UDP, Q_DST);
9178
9179 /* Check that we are operating on version 0. Otherwise, we
9180 * can't decode the rest of the fields. The version is 2 bits
9181 * in the first byte of the Geneve header. */
9182 b1 = gen_mcmp(cstate, offrel, 8, BPF_B, (bpf_int32)0, 0xc0);
9183 gen_and(b0, b1);
9184 b0 = b1;
9185
9186 if (has_vni) {
9187 if (vni > 0xffffff) {
9188 bpf_error(cstate, "Geneve VNI %u greater than maximum %u",
9189 vni, 0xffffff);
9190 }
9191 vni <<= 8; /* VNI is in the upper 3 bytes */
9192 b1 = gen_mcmp(cstate, offrel, 12, BPF_W, (bpf_int32)vni,
9193 0xffffff00);
9194 gen_and(b0, b1);
9195 b0 = b1;
9196 }
9197
9198 return b0;
9199 }
9200
9201 /* The IPv4 and IPv6 Geneve checks need to do two things:
9202 * - Verify that this actually is Geneve with the right VNI.
9203 * - Place the IP header length (plus variable link prefix if
9204 * needed) into register A to be used later to compute
9205 * the inner packet offsets. */
9206 static struct block *
gen_geneve4(compiler_state_t * cstate,bpf_u_int32 vni,int has_vni)9207 gen_geneve4(compiler_state_t *cstate, bpf_u_int32 vni, int has_vni)
9208 {
9209 struct block *b0, *b1;
9210 struct slist *s, *s1;
9211
9212 b0 = gen_geneve_check(cstate, gen_port, OR_TRAN_IPV4, vni, has_vni);
9213
9214 /* Load the IP header length into A. */
9215 s = gen_loadx_iphdrlen(cstate);
9216
9217 s1 = new_stmt(cstate, BPF_MISC|BPF_TXA);
9218 sappend(s, s1);
9219
9220 /* Forcibly append these statements to the true condition
9221 * of the protocol check by creating a new block that is
9222 * always true and ANDing them. */
9223 b1 = new_block(cstate, BPF_JMP|BPF_JEQ|BPF_X);
9224 b1->stmts = s;
9225 b1->s.k = 0;
9226
9227 gen_and(b0, b1);
9228
9229 return b1;
9230 }
9231
9232 static struct block *
gen_geneve6(compiler_state_t * cstate,bpf_u_int32 vni,int has_vni)9233 gen_geneve6(compiler_state_t *cstate, bpf_u_int32 vni, int has_vni)
9234 {
9235 struct block *b0, *b1;
9236 struct slist *s, *s1;
9237
9238 b0 = gen_geneve_check(cstate, gen_port6, OR_TRAN_IPV6, vni, has_vni);
9239
9240 /* Load the IP header length. We need to account for a
9241 * variable length link prefix if there is one. */
9242 s = gen_abs_offset_varpart(cstate, &cstate->off_linkpl);
9243 if (s) {
9244 s1 = new_stmt(cstate, BPF_LD|BPF_IMM);
9245 s1->s.k = 40;
9246 sappend(s, s1);
9247
9248 s1 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X);
9249 s1->s.k = 0;
9250 sappend(s, s1);
9251 } else {
9252 s = new_stmt(cstate, BPF_LD|BPF_IMM);
9253 s->s.k = 40;
9254 }
9255
9256 /* Forcibly append these statements to the true condition
9257 * of the protocol check by creating a new block that is
9258 * always true and ANDing them. */
9259 s1 = new_stmt(cstate, BPF_MISC|BPF_TAX);
9260 sappend(s, s1);
9261
9262 b1 = new_block(cstate, BPF_JMP|BPF_JEQ|BPF_X);
9263 b1->stmts = s;
9264 b1->s.k = 0;
9265
9266 gen_and(b0, b1);
9267
9268 return b1;
9269 }
9270
9271 /* We need to store three values based on the Geneve header::
9272 * - The offset of the linktype.
9273 * - The offset of the end of the Geneve header.
9274 * - The offset of the end of the encapsulated MAC header. */
9275 static struct slist *
gen_geneve_offsets(compiler_state_t * cstate)9276 gen_geneve_offsets(compiler_state_t *cstate)
9277 {
9278 struct slist *s, *s1, *s_proto;
9279
9280 /* First we need to calculate the offset of the Geneve header
9281 * itself. This is composed of the IP header previously calculated
9282 * (include any variable link prefix) and stored in A plus the
9283 * fixed sized headers (fixed link prefix, MAC length, and UDP
9284 * header). */
9285 s = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
9286 s->s.k = cstate->off_linkpl.constant_part + cstate->off_nl + 8;
9287
9288 /* Stash this in X since we'll need it later. */
9289 s1 = new_stmt(cstate, BPF_MISC|BPF_TAX);
9290 sappend(s, s1);
9291
9292 /* The EtherType in Geneve is 2 bytes in. Calculate this and
9293 * store it. */
9294 s1 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
9295 s1->s.k = 2;
9296 sappend(s, s1);
9297
9298 cstate->off_linktype.reg = alloc_reg(cstate);
9299 cstate->off_linktype.is_variable = 1;
9300 cstate->off_linktype.constant_part = 0;
9301
9302 s1 = new_stmt(cstate, BPF_ST);
9303 s1->s.k = cstate->off_linktype.reg;
9304 sappend(s, s1);
9305
9306 /* Load the Geneve option length and mask and shift to get the
9307 * number of bytes. It is stored in the first byte of the Geneve
9308 * header. */
9309 s1 = new_stmt(cstate, BPF_LD|BPF_IND|BPF_B);
9310 s1->s.k = 0;
9311 sappend(s, s1);
9312
9313 s1 = new_stmt(cstate, BPF_ALU|BPF_AND|BPF_K);
9314 s1->s.k = 0x3f;
9315 sappend(s, s1);
9316
9317 s1 = new_stmt(cstate, BPF_ALU|BPF_MUL|BPF_K);
9318 s1->s.k = 4;
9319 sappend(s, s1);
9320
9321 /* Add in the rest of the Geneve base header. */
9322 s1 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
9323 s1->s.k = 8;
9324 sappend(s, s1);
9325
9326 /* Add the Geneve header length to its offset and store. */
9327 s1 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_X);
9328 s1->s.k = 0;
9329 sappend(s, s1);
9330
9331 /* Set the encapsulated type as Ethernet. Even though we may
9332 * not actually have Ethernet inside there are two reasons this
9333 * is useful:
9334 * - The linktype field is always in EtherType format regardless
9335 * of whether it is in Geneve or an inner Ethernet frame.
9336 * - The only link layer that we have specific support for is
9337 * Ethernet. We will confirm that the packet actually is
9338 * Ethernet at runtime before executing these checks. */
9339 PUSH_LINKHDR(cstate, DLT_EN10MB, 1, 0, alloc_reg(cstate));
9340
9341 s1 = new_stmt(cstate, BPF_ST);
9342 s1->s.k = cstate->off_linkhdr.reg;
9343 sappend(s, s1);
9344
9345 /* Calculate whether we have an Ethernet header or just raw IP/
9346 * MPLS/etc. If we have Ethernet, advance the end of the MAC offset
9347 * and linktype by 14 bytes so that the network header can be found
9348 * seamlessly. Otherwise, keep what we've calculated already. */
9349
9350 /* We have a bare jmp so we can't use the optimizer. */
9351 cstate->no_optimize = 1;
9352
9353 /* Load the EtherType in the Geneve header, 2 bytes in. */
9354 s1 = new_stmt(cstate, BPF_LD|BPF_IND|BPF_H);
9355 s1->s.k = 2;
9356 sappend(s, s1);
9357
9358 /* Load X with the end of the Geneve header. */
9359 s1 = new_stmt(cstate, BPF_LDX|BPF_MEM);
9360 s1->s.k = cstate->off_linkhdr.reg;
9361 sappend(s, s1);
9362
9363 /* Check if the EtherType is Transparent Ethernet Bridging. At the
9364 * end of this check, we should have the total length in X. In
9365 * the non-Ethernet case, it's already there. */
9366 s_proto = new_stmt(cstate, JMP(BPF_JEQ));
9367 s_proto->s.k = ETHERTYPE_TEB;
9368 sappend(s, s_proto);
9369
9370 s1 = new_stmt(cstate, BPF_MISC|BPF_TXA);
9371 sappend(s, s1);
9372 s_proto->s.jt = s1;
9373
9374 /* Since this is Ethernet, use the EtherType of the payload
9375 * directly as the linktype. Overwrite what we already have. */
9376 s1 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
9377 s1->s.k = 12;
9378 sappend(s, s1);
9379
9380 s1 = new_stmt(cstate, BPF_ST);
9381 s1->s.k = cstate->off_linktype.reg;
9382 sappend(s, s1);
9383
9384 /* Advance two bytes further to get the end of the Ethernet
9385 * header. */
9386 s1 = new_stmt(cstate, BPF_ALU|BPF_ADD|BPF_K);
9387 s1->s.k = 2;
9388 sappend(s, s1);
9389
9390 /* Move the result to X. */
9391 s1 = new_stmt(cstate, BPF_MISC|BPF_TAX);
9392 sappend(s, s1);
9393
9394 /* Store the final result of our linkpl calculation. */
9395 cstate->off_linkpl.reg = alloc_reg(cstate);
9396 cstate->off_linkpl.is_variable = 1;
9397 cstate->off_linkpl.constant_part = 0;
9398
9399 s1 = new_stmt(cstate, BPF_STX);
9400 s1->s.k = cstate->off_linkpl.reg;
9401 sappend(s, s1);
9402 s_proto->s.jf = s1;
9403
9404 cstate->off_nl = 0;
9405
9406 return s;
9407 }
9408
9409 /* Check to see if this is a Geneve packet. */
9410 struct block *
gen_geneve(compiler_state_t * cstate,bpf_u_int32 vni,int has_vni)9411 gen_geneve(compiler_state_t *cstate, bpf_u_int32 vni, int has_vni)
9412 {
9413 struct block *b0, *b1;
9414 struct slist *s;
9415
9416 /*
9417 * Catch errors reported by us and routines below us, and return NULL
9418 * on an error.
9419 */
9420 if (setjmp(cstate->top_ctx))
9421 return (NULL);
9422
9423 b0 = gen_geneve4(cstate, vni, has_vni);
9424 b1 = gen_geneve6(cstate, vni, has_vni);
9425
9426 gen_or(b0, b1);
9427 b0 = b1;
9428
9429 /* Later filters should act on the payload of the Geneve frame,
9430 * update all of the header pointers. Attach this code so that
9431 * it gets executed in the event that the Geneve filter matches. */
9432 s = gen_geneve_offsets(cstate);
9433
9434 b1 = gen_true(cstate);
9435 sappend(s, b1->stmts);
9436 b1->stmts = s;
9437
9438 gen_and(b0, b1);
9439
9440 cstate->is_geneve = 1;
9441
9442 return b1;
9443 }
9444
9445 /* Check that the encapsulated frame has a link layer header
9446 * for Ethernet filters. */
9447 static struct block *
gen_geneve_ll_check(compiler_state_t * cstate)9448 gen_geneve_ll_check(compiler_state_t *cstate)
9449 {
9450 struct block *b0;
9451 struct slist *s, *s1;
9452
9453 /* The easiest way to see if there is a link layer present
9454 * is to check if the link layer header and payload are not
9455 * the same. */
9456
9457 /* Geneve always generates pure variable offsets so we can
9458 * compare only the registers. */
9459 s = new_stmt(cstate, BPF_LD|BPF_MEM);
9460 s->s.k = cstate->off_linkhdr.reg;
9461
9462 s1 = new_stmt(cstate, BPF_LDX|BPF_MEM);
9463 s1->s.k = cstate->off_linkpl.reg;
9464 sappend(s, s1);
9465
9466 b0 = new_block(cstate, BPF_JMP|BPF_JEQ|BPF_X);
9467 b0->stmts = s;
9468 b0->s.k = 0;
9469 gen_not(b0);
9470
9471 return b0;
9472 }
9473
9474 static struct block *
gen_atmfield_code_internal(compiler_state_t * cstate,int atmfield,bpf_int32 jvalue,bpf_u_int32 jtype,int reverse)9475 gen_atmfield_code_internal(compiler_state_t *cstate, int atmfield,
9476 bpf_int32 jvalue, bpf_u_int32 jtype, int reverse)
9477 {
9478 struct block *b0;
9479
9480 switch (atmfield) {
9481
9482 case A_VPI:
9483 if (!cstate->is_atm)
9484 bpf_error(cstate, "'vpi' supported only on raw ATM");
9485 if (cstate->off_vpi == OFFSET_NOT_SET)
9486 abort();
9487 b0 = gen_ncmp(cstate, OR_LINKHDR, cstate->off_vpi, BPF_B, 0xffffffff, jtype,
9488 reverse, jvalue);
9489 break;
9490
9491 case A_VCI:
9492 if (!cstate->is_atm)
9493 bpf_error(cstate, "'vci' supported only on raw ATM");
9494 if (cstate->off_vci == OFFSET_NOT_SET)
9495 abort();
9496 b0 = gen_ncmp(cstate, OR_LINKHDR, cstate->off_vci, BPF_H, 0xffffffff, jtype,
9497 reverse, jvalue);
9498 break;
9499
9500 case A_PROTOTYPE:
9501 if (cstate->off_proto == OFFSET_NOT_SET)
9502 abort(); /* XXX - this isn't on FreeBSD */
9503 b0 = gen_ncmp(cstate, OR_LINKHDR, cstate->off_proto, BPF_B, 0x0f, jtype,
9504 reverse, jvalue);
9505 break;
9506
9507 case A_MSGTYPE:
9508 if (cstate->off_payload == OFFSET_NOT_SET)
9509 abort();
9510 b0 = gen_ncmp(cstate, OR_LINKHDR, cstate->off_payload + MSG_TYPE_POS, BPF_B,
9511 0xffffffff, jtype, reverse, jvalue);
9512 break;
9513
9514 case A_CALLREFTYPE:
9515 if (!cstate->is_atm)
9516 bpf_error(cstate, "'callref' supported only on raw ATM");
9517 if (cstate->off_proto == OFFSET_NOT_SET)
9518 abort();
9519 b0 = gen_ncmp(cstate, OR_LINKHDR, cstate->off_proto, BPF_B, 0xffffffff,
9520 jtype, reverse, jvalue);
9521 break;
9522
9523 default:
9524 abort();
9525 }
9526 return b0;
9527 }
9528
9529 static struct block *
gen_atmtype_metac(compiler_state_t * cstate)9530 gen_atmtype_metac(compiler_state_t *cstate)
9531 {
9532 struct block *b0, *b1;
9533
9534 b0 = gen_atmfield_code_internal(cstate, A_VPI, 0, BPF_JEQ, 0);
9535 b1 = gen_atmfield_code_internal(cstate, A_VCI, 1, BPF_JEQ, 0);
9536 gen_and(b0, b1);
9537 return b1;
9538 }
9539
9540 static struct block *
gen_atmtype_sc(compiler_state_t * cstate)9541 gen_atmtype_sc(compiler_state_t *cstate)
9542 {
9543 struct block *b0, *b1;
9544
9545 b0 = gen_atmfield_code_internal(cstate, A_VPI, 0, BPF_JEQ, 0);
9546 b1 = gen_atmfield_code_internal(cstate, A_VCI, 5, BPF_JEQ, 0);
9547 gen_and(b0, b1);
9548 return b1;
9549 }
9550
9551 static struct block *
gen_atmtype_llc(compiler_state_t * cstate)9552 gen_atmtype_llc(compiler_state_t *cstate)
9553 {
9554 struct block *b0;
9555
9556 b0 = gen_atmfield_code_internal(cstate, A_PROTOTYPE, PT_LLC, BPF_JEQ, 0);
9557 cstate->linktype = cstate->prevlinktype;
9558 return b0;
9559 }
9560
9561 struct block *
gen_atmfield_code(compiler_state_t * cstate,int atmfield,bpf_int32 jvalue,bpf_u_int32 jtype,int reverse)9562 gen_atmfield_code(compiler_state_t *cstate, int atmfield,
9563 bpf_int32 jvalue, bpf_u_int32 jtype, int reverse)
9564 {
9565 /*
9566 * Catch errors reported by us and routines below us, and return NULL
9567 * on an error.
9568 */
9569 if (setjmp(cstate->top_ctx))
9570 return (NULL);
9571
9572 return gen_atmfield_code_internal(cstate, atmfield, jvalue, jtype,
9573 reverse);
9574 }
9575
9576 struct block *
gen_atmtype_abbrev(compiler_state_t * cstate,int type)9577 gen_atmtype_abbrev(compiler_state_t *cstate, int type)
9578 {
9579 struct block *b0, *b1;
9580
9581 /*
9582 * Catch errors reported by us and routines below us, and return NULL
9583 * on an error.
9584 */
9585 if (setjmp(cstate->top_ctx))
9586 return (NULL);
9587
9588 switch (type) {
9589
9590 case A_METAC:
9591 /* Get all packets in Meta signalling Circuit */
9592 if (!cstate->is_atm)
9593 bpf_error(cstate, "'metac' supported only on raw ATM");
9594 b1 = gen_atmtype_metac(cstate);
9595 break;
9596
9597 case A_BCC:
9598 /* Get all packets in Broadcast Circuit*/
9599 if (!cstate->is_atm)
9600 bpf_error(cstate, "'bcc' supported only on raw ATM");
9601 b0 = gen_atmfield_code_internal(cstate, A_VPI, 0, BPF_JEQ, 0);
9602 b1 = gen_atmfield_code_internal(cstate, A_VCI, 2, BPF_JEQ, 0);
9603 gen_and(b0, b1);
9604 break;
9605
9606 case A_OAMF4SC:
9607 /* Get all cells in Segment OAM F4 circuit*/
9608 if (!cstate->is_atm)
9609 bpf_error(cstate, "'oam4sc' supported only on raw ATM");
9610 b0 = gen_atmfield_code_internal(cstate, A_VPI, 0, BPF_JEQ, 0);
9611 b1 = gen_atmfield_code_internal(cstate, A_VCI, 3, BPF_JEQ, 0);
9612 gen_and(b0, b1);
9613 break;
9614
9615 case A_OAMF4EC:
9616 /* Get all cells in End-to-End OAM F4 Circuit*/
9617 if (!cstate->is_atm)
9618 bpf_error(cstate, "'oam4ec' supported only on raw ATM");
9619 b0 = gen_atmfield_code_internal(cstate, A_VPI, 0, BPF_JEQ, 0);
9620 b1 = gen_atmfield_code_internal(cstate, A_VCI, 4, BPF_JEQ, 0);
9621 gen_and(b0, b1);
9622 break;
9623
9624 case A_SC:
9625 /* Get all packets in connection Signalling Circuit */
9626 if (!cstate->is_atm)
9627 bpf_error(cstate, "'sc' supported only on raw ATM");
9628 b1 = gen_atmtype_sc(cstate);
9629 break;
9630
9631 case A_ILMIC:
9632 /* Get all packets in ILMI Circuit */
9633 if (!cstate->is_atm)
9634 bpf_error(cstate, "'ilmic' supported only on raw ATM");
9635 b0 = gen_atmfield_code_internal(cstate, A_VPI, 0, BPF_JEQ, 0);
9636 b1 = gen_atmfield_code_internal(cstate, A_VCI, 16, BPF_JEQ, 0);
9637 gen_and(b0, b1);
9638 break;
9639
9640 case A_LANE:
9641 /* Get all LANE packets */
9642 if (!cstate->is_atm)
9643 bpf_error(cstate, "'lane' supported only on raw ATM");
9644 b1 = gen_atmfield_code_internal(cstate, A_PROTOTYPE, PT_LANE, BPF_JEQ, 0);
9645
9646 /*
9647 * Arrange that all subsequent tests assume LANE
9648 * rather than LLC-encapsulated packets, and set
9649 * the offsets appropriately for LANE-encapsulated
9650 * Ethernet.
9651 *
9652 * We assume LANE means Ethernet, not Token Ring.
9653 */
9654 PUSH_LINKHDR(cstate, DLT_EN10MB, 0,
9655 cstate->off_payload + 2, /* Ethernet header */
9656 -1);
9657 cstate->off_linktype.constant_part = cstate->off_linkhdr.constant_part + 12;
9658 cstate->off_linkpl.constant_part = cstate->off_linkhdr.constant_part + 14; /* Ethernet */
9659 cstate->off_nl = 0; /* Ethernet II */
9660 cstate->off_nl_nosnap = 3; /* 802.3+802.2 */
9661 break;
9662
9663 case A_LLC:
9664 /* Get all LLC-encapsulated packets */
9665 if (!cstate->is_atm)
9666 bpf_error(cstate, "'llc' supported only on raw ATM");
9667 b1 = gen_atmtype_llc(cstate);
9668 break;
9669
9670 default:
9671 abort();
9672 }
9673 return b1;
9674 }
9675
9676 /*
9677 * Filtering for MTP2 messages based on li value
9678 * FISU, length is null
9679 * LSSU, length is 1 or 2
9680 * MSU, length is 3 or more
9681 * For MTP2_HSL, sequences are on 2 bytes, and length on 9 bits
9682 */
9683 struct block *
gen_mtp2type_abbrev(compiler_state_t * cstate,int type)9684 gen_mtp2type_abbrev(compiler_state_t *cstate, int type)
9685 {
9686 struct block *b0, *b1;
9687
9688 /*
9689 * Catch errors reported by us and routines below us, and return NULL
9690 * on an error.
9691 */
9692 if (setjmp(cstate->top_ctx))
9693 return (NULL);
9694
9695 switch (type) {
9696
9697 case M_FISU:
9698 if ( (cstate->linktype != DLT_MTP2) &&
9699 (cstate->linktype != DLT_ERF) &&
9700 (cstate->linktype != DLT_MTP2_WITH_PHDR) )
9701 bpf_error(cstate, "'fisu' supported only on MTP2");
9702 /* gen_ncmp(cstate, offrel, offset, size, mask, jtype, reverse, value) */
9703 b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li, BPF_B, 0x3f, BPF_JEQ, 0, 0);
9704 break;
9705
9706 case M_LSSU:
9707 if ( (cstate->linktype != DLT_MTP2) &&
9708 (cstate->linktype != DLT_ERF) &&
9709 (cstate->linktype != DLT_MTP2_WITH_PHDR) )
9710 bpf_error(cstate, "'lssu' supported only on MTP2");
9711 b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li, BPF_B, 0x3f, BPF_JGT, 1, 2);
9712 b1 = gen_ncmp(cstate, OR_PACKET, cstate->off_li, BPF_B, 0x3f, BPF_JGT, 0, 0);
9713 gen_and(b1, b0);
9714 break;
9715
9716 case M_MSU:
9717 if ( (cstate->linktype != DLT_MTP2) &&
9718 (cstate->linktype != DLT_ERF) &&
9719 (cstate->linktype != DLT_MTP2_WITH_PHDR) )
9720 bpf_error(cstate, "'msu' supported only on MTP2");
9721 b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li, BPF_B, 0x3f, BPF_JGT, 0, 2);
9722 break;
9723
9724 case MH_FISU:
9725 if ( (cstate->linktype != DLT_MTP2) &&
9726 (cstate->linktype != DLT_ERF) &&
9727 (cstate->linktype != DLT_MTP2_WITH_PHDR) )
9728 bpf_error(cstate, "'hfisu' supported only on MTP2_HSL");
9729 /* gen_ncmp(cstate, offrel, offset, size, mask, jtype, reverse, value) */
9730 b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li_hsl, BPF_H, 0xff80, BPF_JEQ, 0, 0);
9731 break;
9732
9733 case MH_LSSU:
9734 if ( (cstate->linktype != DLT_MTP2) &&
9735 (cstate->linktype != DLT_ERF) &&
9736 (cstate->linktype != DLT_MTP2_WITH_PHDR) )
9737 bpf_error(cstate, "'hlssu' supported only on MTP2_HSL");
9738 b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li_hsl, BPF_H, 0xff80, BPF_JGT, 1, 0x0100);
9739 b1 = gen_ncmp(cstate, OR_PACKET, cstate->off_li_hsl, BPF_H, 0xff80, BPF_JGT, 0, 0);
9740 gen_and(b1, b0);
9741 break;
9742
9743 case MH_MSU:
9744 if ( (cstate->linktype != DLT_MTP2) &&
9745 (cstate->linktype != DLT_ERF) &&
9746 (cstate->linktype != DLT_MTP2_WITH_PHDR) )
9747 bpf_error(cstate, "'hmsu' supported only on MTP2_HSL");
9748 b0 = gen_ncmp(cstate, OR_PACKET, cstate->off_li_hsl, BPF_H, 0xff80, BPF_JGT, 0, 0x0100);
9749 break;
9750
9751 default:
9752 abort();
9753 }
9754 return b0;
9755 }
9756
9757 /*
9758 * The jvalue_arg dance is to avoid annoying whining by compilers that
9759 * jvalue might be clobbered by longjmp - yeah, it might, but *WHO CARES*?
9760 * It's not *used* after setjmp returns.
9761 */
9762 struct block *
gen_mtp3field_code(compiler_state_t * cstate,int mtp3field,bpf_u_int32 jvalue_arg,bpf_u_int32 jtype,int reverse)9763 gen_mtp3field_code(compiler_state_t *cstate, int mtp3field,
9764 bpf_u_int32 jvalue_arg, bpf_u_int32 jtype, int reverse)
9765 {
9766 volatile bpf_u_int32 jvalue = jvalue_arg;
9767 struct block *b0;
9768 bpf_u_int32 val1 , val2 , val3;
9769 u_int newoff_sio;
9770 u_int newoff_opc;
9771 u_int newoff_dpc;
9772 u_int newoff_sls;
9773
9774 /*
9775 * Catch errors reported by us and routines below us, and return NULL
9776 * on an error.
9777 */
9778 if (setjmp(cstate->top_ctx))
9779 return (NULL);
9780
9781 newoff_sio = cstate->off_sio;
9782 newoff_opc = cstate->off_opc;
9783 newoff_dpc = cstate->off_dpc;
9784 newoff_sls = cstate->off_sls;
9785 switch (mtp3field) {
9786
9787 case MH_SIO:
9788 newoff_sio += 3; /* offset for MTP2_HSL */
9789 /* FALLTHROUGH */
9790
9791 case M_SIO:
9792 if (cstate->off_sio == OFFSET_NOT_SET)
9793 bpf_error(cstate, "'sio' supported only on SS7");
9794 /* sio coded on 1 byte so max value 255 */
9795 if(jvalue > 255)
9796 bpf_error(cstate, "sio value %u too big; max value = 255",
9797 jvalue);
9798 b0 = gen_ncmp(cstate, OR_PACKET, newoff_sio, BPF_B, 0xffffffff,
9799 (u_int)jtype, reverse, (u_int)jvalue);
9800 break;
9801
9802 case MH_OPC:
9803 newoff_opc += 3;
9804
9805 /* FALLTHROUGH */
9806 case M_OPC:
9807 if (cstate->off_opc == OFFSET_NOT_SET)
9808 bpf_error(cstate, "'opc' supported only on SS7");
9809 /* opc coded on 14 bits so max value 16383 */
9810 if (jvalue > 16383)
9811 bpf_error(cstate, "opc value %u too big; max value = 16383",
9812 jvalue);
9813 /* the following instructions are made to convert jvalue
9814 * to the form used to write opc in an ss7 message*/
9815 val1 = jvalue & 0x00003c00;
9816 val1 = val1 >>10;
9817 val2 = jvalue & 0x000003fc;
9818 val2 = val2 <<6;
9819 val3 = jvalue & 0x00000003;
9820 val3 = val3 <<22;
9821 jvalue = val1 + val2 + val3;
9822 b0 = gen_ncmp(cstate, OR_PACKET, newoff_opc, BPF_W, 0x00c0ff0f,
9823 (u_int)jtype, reverse, (u_int)jvalue);
9824 break;
9825
9826 case MH_DPC:
9827 newoff_dpc += 3;
9828 /* FALLTHROUGH */
9829
9830 case M_DPC:
9831 if (cstate->off_dpc == OFFSET_NOT_SET)
9832 bpf_error(cstate, "'dpc' supported only on SS7");
9833 /* dpc coded on 14 bits so max value 16383 */
9834 if (jvalue > 16383)
9835 bpf_error(cstate, "dpc value %u too big; max value = 16383",
9836 jvalue);
9837 /* the following instructions are made to convert jvalue
9838 * to the forme used to write dpc in an ss7 message*/
9839 val1 = jvalue & 0x000000ff;
9840 val1 = val1 << 24;
9841 val2 = jvalue & 0x00003f00;
9842 val2 = val2 << 8;
9843 jvalue = val1 + val2;
9844 b0 = gen_ncmp(cstate, OR_PACKET, newoff_dpc, BPF_W, 0xff3f0000,
9845 (u_int)jtype, reverse, (u_int)jvalue);
9846 break;
9847
9848 case MH_SLS:
9849 newoff_sls += 3;
9850 /* FALLTHROUGH */
9851
9852 case M_SLS:
9853 if (cstate->off_sls == OFFSET_NOT_SET)
9854 bpf_error(cstate, "'sls' supported only on SS7");
9855 /* sls coded on 4 bits so max value 15 */
9856 if (jvalue > 15)
9857 bpf_error(cstate, "sls value %u too big; max value = 15",
9858 jvalue);
9859 /* the following instruction is made to convert jvalue
9860 * to the forme used to write sls in an ss7 message*/
9861 jvalue = jvalue << 4;
9862 b0 = gen_ncmp(cstate, OR_PACKET, newoff_sls, BPF_B, 0xf0,
9863 (u_int)jtype,reverse, (u_int)jvalue);
9864 break;
9865
9866 default:
9867 abort();
9868 }
9869 return b0;
9870 }
9871
9872 static struct block *
gen_msg_abbrev(compiler_state_t * cstate,int type)9873 gen_msg_abbrev(compiler_state_t *cstate, int type)
9874 {
9875 struct block *b1;
9876
9877 /*
9878 * Q.2931 signalling protocol messages for handling virtual circuits
9879 * establishment and teardown
9880 */
9881 switch (type) {
9882
9883 case A_SETUP:
9884 b1 = gen_atmfield_code_internal(cstate, A_MSGTYPE, SETUP, BPF_JEQ, 0);
9885 break;
9886
9887 case A_CALLPROCEED:
9888 b1 = gen_atmfield_code_internal(cstate, A_MSGTYPE, CALL_PROCEED, BPF_JEQ, 0);
9889 break;
9890
9891 case A_CONNECT:
9892 b1 = gen_atmfield_code_internal(cstate, A_MSGTYPE, CONNECT, BPF_JEQ, 0);
9893 break;
9894
9895 case A_CONNECTACK:
9896 b1 = gen_atmfield_code_internal(cstate, A_MSGTYPE, CONNECT_ACK, BPF_JEQ, 0);
9897 break;
9898
9899 case A_RELEASE:
9900 b1 = gen_atmfield_code_internal(cstate, A_MSGTYPE, RELEASE, BPF_JEQ, 0);
9901 break;
9902
9903 case A_RELEASE_DONE:
9904 b1 = gen_atmfield_code_internal(cstate, A_MSGTYPE, RELEASE_DONE, BPF_JEQ, 0);
9905 break;
9906
9907 default:
9908 abort();
9909 }
9910 return b1;
9911 }
9912
9913 struct block *
gen_atmmulti_abbrev(compiler_state_t * cstate,int type)9914 gen_atmmulti_abbrev(compiler_state_t *cstate, int type)
9915 {
9916 struct block *b0, *b1;
9917
9918 /*
9919 * Catch errors reported by us and routines below us, and return NULL
9920 * on an error.
9921 */
9922 if (setjmp(cstate->top_ctx))
9923 return (NULL);
9924
9925 switch (type) {
9926
9927 case A_OAM:
9928 if (!cstate->is_atm)
9929 bpf_error(cstate, "'oam' supported only on raw ATM");
9930 /* OAM F4 type */
9931 b0 = gen_atmfield_code_internal(cstate, A_VCI, 3, BPF_JEQ, 0);
9932 b1 = gen_atmfield_code_internal(cstate, A_VCI, 4, BPF_JEQ, 0);
9933 gen_or(b0, b1);
9934 b0 = gen_atmfield_code_internal(cstate, A_VPI, 0, BPF_JEQ, 0);
9935 gen_and(b0, b1);
9936 break;
9937
9938 case A_OAMF4:
9939 if (!cstate->is_atm)
9940 bpf_error(cstate, "'oamf4' supported only on raw ATM");
9941 /* OAM F4 type */
9942 b0 = gen_atmfield_code_internal(cstate, A_VCI, 3, BPF_JEQ, 0);
9943 b1 = gen_atmfield_code_internal(cstate, A_VCI, 4, BPF_JEQ, 0);
9944 gen_or(b0, b1);
9945 b0 = gen_atmfield_code_internal(cstate, A_VPI, 0, BPF_JEQ, 0);
9946 gen_and(b0, b1);
9947 break;
9948
9949 case A_CONNECTMSG:
9950 /*
9951 * Get Q.2931 signalling messages for switched
9952 * virtual connection
9953 */
9954 if (!cstate->is_atm)
9955 bpf_error(cstate, "'connectmsg' supported only on raw ATM");
9956 b0 = gen_msg_abbrev(cstate, A_SETUP);
9957 b1 = gen_msg_abbrev(cstate, A_CALLPROCEED);
9958 gen_or(b0, b1);
9959 b0 = gen_msg_abbrev(cstate, A_CONNECT);
9960 gen_or(b0, b1);
9961 b0 = gen_msg_abbrev(cstate, A_CONNECTACK);
9962 gen_or(b0, b1);
9963 b0 = gen_msg_abbrev(cstate, A_RELEASE);
9964 gen_or(b0, b1);
9965 b0 = gen_msg_abbrev(cstate, A_RELEASE_DONE);
9966 gen_or(b0, b1);
9967 b0 = gen_atmtype_sc(cstate);
9968 gen_and(b0, b1);
9969 break;
9970
9971 case A_METACONNECT:
9972 if (!cstate->is_atm)
9973 bpf_error(cstate, "'metaconnect' supported only on raw ATM");
9974 b0 = gen_msg_abbrev(cstate, A_SETUP);
9975 b1 = gen_msg_abbrev(cstate, A_CALLPROCEED);
9976 gen_or(b0, b1);
9977 b0 = gen_msg_abbrev(cstate, A_CONNECT);
9978 gen_or(b0, b1);
9979 b0 = gen_msg_abbrev(cstate, A_RELEASE);
9980 gen_or(b0, b1);
9981 b0 = gen_msg_abbrev(cstate, A_RELEASE_DONE);
9982 gen_or(b0, b1);
9983 b0 = gen_atmtype_metac(cstate);
9984 gen_and(b0, b1);
9985 break;
9986
9987 default:
9988 abort();
9989 }
9990 return b1;
9991 }
9992