1 /* $NetBSD: pcap-snit.c,v 1.5 2018/09/03 15:26:43 christos Exp $ */
2
3 /*
4 * Copyright (c) 1990, 1991, 1992, 1993, 1994, 1995, 1996
5 * The Regents of the University of California. All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that: (1) source code distributions
9 * retain the above copyright notice and this paragraph in its entirety, (2)
10 * distributions including binary code include the above copyright notice and
11 * this paragraph in its entirety in the documentation or other materials
12 * provided with the distribution, and (3) all advertising materials mentioning
13 * features or use of this software display the following acknowledgement:
14 * ``This product includes software developed by the University of California,
15 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
16 * the University nor the names of its contributors may be used to endorse
17 * or promote products derived from this software without specific prior
18 * written permission.
19 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
20 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
21 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
22 *
23 * Modifications made to accommodate the new SunOS4.0 NIT facility by
24 * Micky Liu, micky@cunixc.cc.columbia.edu, Columbia University in May, 1989.
25 * This module now handles the STREAMS based NIT.
26 */
27
28 #include <sys/cdefs.h>
29 __RCSID("$NetBSD: pcap-snit.c,v 1.5 2018/09/03 15:26:43 christos Exp $");
30
31 #ifdef HAVE_CONFIG_H
32 #include <config.h>
33 #endif
34
35 #include <sys/types.h>
36 #include <sys/time.h>
37 #include <sys/timeb.h>
38 #include <sys/dir.h>
39 #include <sys/fcntlcom.h>
40 #include <sys/file.h>
41 #include <sys/ioctl.h>
42 #include <sys/socket.h>
43 #include <sys/stropts.h>
44
45 #include <net/if.h>
46 #include <net/nit.h>
47 #include <net/nit_if.h>
48 #include <net/nit_pf.h>
49 #include <net/nit_buf.h>
50
51 #include <netinet/in.h>
52 #include <netinet/in_systm.h>
53 #include <netinet/ip.h>
54 #include <netinet/if_ether.h>
55 #include <netinet/ip_var.h>
56 #include <netinet/udp.h>
57 #include <netinet/udp_var.h>
58 #include <netinet/tcp.h>
59 #include <netinet/tcpip.h>
60
61 #include <ctype.h>
62 #include <errno.h>
63 #include <stdio.h>
64 #include <string.h>
65 #include <unistd.h>
66
67 #include "pcap-int.h"
68
69 #ifdef HAVE_OS_PROTO_H
70 #include "os-proto.h"
71 #endif
72
73 /*
74 * The chunk size for NIT. This is the amount of buffering
75 * done for read calls.
76 */
77 #define CHUNKSIZE (2*1024)
78
79 /*
80 * The total buffer space used by NIT.
81 */
82 #define BUFSPACE (4*CHUNKSIZE)
83
84 /* Forwards */
85 static int nit_setflags(int, int, int, char *);
86
87 /*
88 * Private data for capturing on STREAMS NIT devices.
89 */
90 struct pcap_snit {
91 struct pcap_stat stat;
92 };
93
94 static int
pcap_stats_snit(pcap_t * p,struct pcap_stat * ps)95 pcap_stats_snit(pcap_t *p, struct pcap_stat *ps)
96 {
97 struct pcap_snit *psn = p->priv;
98
99 /*
100 * "ps_recv" counts packets handed to the filter, not packets
101 * that passed the filter. As filtering is done in userland,
102 * this does not include packets dropped because we ran out
103 * of buffer space.
104 *
105 * "ps_drop" counts packets dropped inside the "/dev/nit"
106 * device because of flow control requirements or resource
107 * exhaustion; it doesn't count packets dropped by the
108 * interface driver, or packets dropped upstream. As filtering
109 * is done in userland, it counts packets regardless of whether
110 * they would've passed the filter.
111 *
112 * These statistics don't include packets not yet read from the
113 * kernel by libpcap or packets not yet read from libpcap by the
114 * application.
115 */
116 *ps = psn->stat;
117 return (0);
118 }
119
120 static int
pcap_read_snit(pcap_t * p,int cnt,pcap_handler callback,u_char * user)121 pcap_read_snit(pcap_t *p, int cnt, pcap_handler callback, u_char *user)
122 {
123 struct pcap_snit *psn = p->priv;
124 register int cc, n;
125 register u_char *bp, *cp, *ep;
126 register struct nit_bufhdr *hdrp;
127 register struct nit_iftime *ntp;
128 register struct nit_iflen *nlp;
129 register struct nit_ifdrops *ndp;
130 register int caplen;
131
132 cc = p->cc;
133 if (cc == 0) {
134 cc = read(p->fd, (char *)p->buffer, p->bufsize);
135 if (cc < 0) {
136 if (errno == EWOULDBLOCK)
137 return (0);
138 pcap_fmt_errmsg_for_errno(p->errbuf, sizeof(p->errbuf),
139 errno, "pcap_read");
140 return (-1);
141 }
142 bp = (u_char *)p->buffer;
143 } else
144 bp = p->bp;
145
146 /*
147 * loop through each snapshot in the chunk
148 */
149 n = 0;
150 ep = bp + cc;
151 while (bp < ep) {
152 /*
153 * Has "pcap_breakloop()" been called?
154 * If so, return immediately - if we haven't read any
155 * packets, clear the flag and return -2 to indicate
156 * that we were told to break out of the loop, otherwise
157 * leave the flag set, so that the *next* call will break
158 * out of the loop without having read any packets, and
159 * return the number of packets we've processed so far.
160 */
161 if (p->break_loop) {
162 if (n == 0) {
163 p->break_loop = 0;
164 return (-2);
165 } else {
166 p->bp = bp;
167 p->cc = ep - bp;
168 return (n);
169 }
170 }
171
172 ++psn->stat.ps_recv;
173 cp = bp;
174
175 /* get past NIT buffer */
176 hdrp = (struct nit_bufhdr *)cp;
177 cp += sizeof(*hdrp);
178
179 /* get past NIT timer */
180 ntp = (struct nit_iftime *)cp;
181 cp += sizeof(*ntp);
182
183 ndp = (struct nit_ifdrops *)cp;
184 psn->stat.ps_drop = ndp->nh_drops;
185 cp += sizeof *ndp;
186
187 /* get past packet len */
188 nlp = (struct nit_iflen *)cp;
189 cp += sizeof(*nlp);
190
191 /* next snapshot */
192 bp += hdrp->nhb_totlen;
193
194 caplen = nlp->nh_pktlen;
195 if (caplen > p->snapshot)
196 caplen = p->snapshot;
197
198 if (bpf_filter(p->fcode.bf_insns, cp, nlp->nh_pktlen, caplen)) {
199 struct pcap_pkthdr h;
200 h.ts = ntp->nh_timestamp;
201 h.len = nlp->nh_pktlen;
202 h.caplen = caplen;
203 (*callback)(user, &h, cp);
204 if (++n >= cnt && !PACKET_COUNT_IS_UNLIMITED(cnt)) {
205 p->cc = ep - bp;
206 p->bp = bp;
207 return (n);
208 }
209 }
210 }
211 p->cc = 0;
212 return (n);
213 }
214
215 static int
pcap_inject_snit(pcap_t * p,const void * buf,size_t size)216 pcap_inject_snit(pcap_t *p, const void *buf, size_t size)
217 {
218 struct strbuf ctl, data;
219
220 /*
221 * XXX - can we just do
222 *
223 ret = write(pd->f, buf, size);
224 */
225 ctl.len = sizeof(*sa); /* XXX - what was this? */
226 ctl.buf = (char *)sa;
227 data.buf = buf;
228 data.len = size;
229 ret = putmsg(p->fd, &ctl, &data);
230 if (ret == -1) {
231 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
232 errno, "send");
233 return (-1);
234 }
235 return (ret);
236 }
237
238 static int
nit_setflags(pcap_t * p)239 nit_setflags(pcap_t *p)
240 {
241 bpf_u_int32 flags;
242 struct strioctl si;
243 u_int zero = 0;
244 struct timeval timeout;
245
246 if (p->opt.immediate) {
247 /*
248 * Set the chunk size to zero, so that chunks get sent
249 * up immediately.
250 */
251 si.ic_cmd = NIOCSCHUNK;
252 si.ic_len = sizeof(zero);
253 si.ic_dp = (char *)&zero;
254 if (ioctl(p->fd, I_STR, (char *)&si) < 0) {
255 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
256 errno, "NIOCSCHUNK");
257 return (-1);
258 }
259 }
260 si.ic_timout = INFTIM;
261 if (p->opt.timeout != 0) {
262 timeout.tv_sec = p->opt.timeout / 1000;
263 timeout.tv_usec = (p->opt.timeout * 1000) % 1000000;
264 si.ic_cmd = NIOCSTIME;
265 si.ic_len = sizeof(timeout);
266 si.ic_dp = (char *)&timeout;
267 if (ioctl(p->fd, I_STR, (char *)&si) < 0) {
268 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
269 errno, "NIOCSTIME");
270 return (-1);
271 }
272 }
273 flags = NI_TIMESTAMP | NI_LEN | NI_DROPS;
274 if (p->opt.promisc)
275 flags |= NI_PROMISC;
276 si.ic_cmd = NIOCSFLAGS;
277 si.ic_len = sizeof(flags);
278 si.ic_dp = (char *)&flags;
279 if (ioctl(p->fd, I_STR, (char *)&si) < 0) {
280 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
281 errno, "NIOCSFLAGS");
282 return (-1);
283 }
284 return (0);
285 }
286
287 static int
pcap_activate_snit(pcap_t * p)288 pcap_activate_snit(pcap_t *p)
289 {
290 struct strioctl si; /* struct for ioctl() */
291 struct ifreq ifr; /* interface request struct */
292 int chunksize = CHUNKSIZE;
293 int fd;
294 static const char dev[] = "/dev/nit";
295 int err;
296
297 if (p->opt.rfmon) {
298 /*
299 * No monitor mode on SunOS 4.x (no Wi-Fi devices on
300 * hardware supported by SunOS 4.x).
301 */
302 return (PCAP_ERROR_RFMON_NOTSUP);
303 }
304
305 /*
306 * Turn a negative snapshot value (invalid), a snapshot value of
307 * 0 (unspecified), or a value bigger than the normal maximum
308 * value, into the maximum allowed value.
309 *
310 * If some application really *needs* a bigger snapshot
311 * length, we should just increase MAXIMUM_SNAPLEN.
312 */
313 if (p->snapshot <= 0 || p->snapshot > MAXIMUM_SNAPLEN)
314 p->snapshot = MAXIMUM_SNAPLEN;
315
316 if (p->snapshot < 96)
317 /*
318 * NIT requires a snapshot length of at least 96.
319 */
320 p->snapshot = 96;
321
322 /*
323 * Initially try a read/write open (to allow the inject
324 * method to work). If that fails due to permission
325 * issues, fall back to read-only. This allows a
326 * non-root user to be granted specific access to pcap
327 * capabilities via file permissions.
328 *
329 * XXX - we should have an API that has a flag that
330 * controls whether to open read-only or read-write,
331 * so that denial of permission to send (or inability
332 * to send, if sending packets isn't supported on
333 * the device in question) can be indicated at open
334 * time.
335 */
336 p->fd = fd = open(dev, O_RDWR);
337 if (fd < 0 && errno == EACCES)
338 p->fd = fd = open(dev, O_RDONLY);
339 if (fd < 0) {
340 if (errno == EACCES)
341 err = PCAP_ERROR_PERM_DENIED;
342 else
343 err = PCAP_ERROR;
344 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
345 errno, "%s", dev);
346 goto bad;
347 }
348
349 /* arrange to get discrete messages from the STREAM and use NIT_BUF */
350 if (ioctl(fd, I_SRDOPT, (char *)RMSGD) < 0) {
351 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
352 errno, "I_SRDOPT");
353 err = PCAP_ERROR;
354 goto bad;
355 }
356 if (ioctl(fd, I_PUSH, "nbuf") < 0) {
357 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
358 errno, "push nbuf");
359 err = PCAP_ERROR;
360 goto bad;
361 }
362 /* set the chunksize */
363 si.ic_cmd = NIOCSCHUNK;
364 si.ic_timout = INFTIM;
365 si.ic_len = sizeof(chunksize);
366 si.ic_dp = (char *)&chunksize;
367 if (ioctl(fd, I_STR, (char *)&si) < 0) {
368 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
369 errno, "NIOCSCHUNK");
370 err = PCAP_ERROR;
371 goto bad;
372 }
373
374 /* request the interface */
375 strncpy(ifr.ifr_name, p->opt.device, sizeof(ifr.ifr_name));
376 ifr.ifr_name[sizeof(ifr.ifr_name) - 1] = '\0';
377 si.ic_cmd = NIOCBIND;
378 si.ic_len = sizeof(ifr);
379 si.ic_dp = (char *)𝔦
380 if (ioctl(fd, I_STR, (char *)&si) < 0) {
381 /*
382 * XXX - is there an error that means "no such device"?
383 * Is there one that means "that device doesn't support
384 * STREAMS NIT"?
385 */
386 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
387 errno, "NIOCBIND: %s", ifr.ifr_name);
388 err = PCAP_ERROR;
389 goto bad;
390 }
391
392 /* set the snapshot length */
393 si.ic_cmd = NIOCSSNAP;
394 si.ic_len = sizeof(p->snapshot);
395 si.ic_dp = (char *)&p->snapshot;
396 if (ioctl(fd, I_STR, (char *)&si) < 0) {
397 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
398 errno, "NIOCSSNAP");
399 err = PCAP_ERROR;
400 goto bad;
401 }
402 if (nit_setflags(p) < 0) {
403 err = PCAP_ERROR;
404 goto bad;
405 }
406
407 (void)ioctl(fd, I_FLUSH, (char *)FLUSHR);
408 /*
409 * NIT supports only ethernets.
410 */
411 p->linktype = DLT_EN10MB;
412
413 p->bufsize = BUFSPACE;
414 p->buffer = malloc(p->bufsize);
415 if (p->buffer == NULL) {
416 pcap_fmt_errmsg_for_errno(p->errbuf, PCAP_ERRBUF_SIZE,
417 errno, "malloc");
418 err = PCAP_ERROR;
419 goto bad;
420 }
421
422 /*
423 * "p->fd" is an FD for a STREAMS device, so "select()" and
424 * "poll()" should work on it.
425 */
426 p->selectable_fd = p->fd;
427
428 /*
429 * This is (presumably) a real Ethernet capture; give it a
430 * link-layer-type list with DLT_EN10MB and DLT_DOCSIS, so
431 * that an application can let you choose it, in case you're
432 * capturing DOCSIS traffic that a Cisco Cable Modem
433 * Termination System is putting out onto an Ethernet (it
434 * doesn't put an Ethernet header onto the wire, it puts raw
435 * DOCSIS frames out on the wire inside the low-level
436 * Ethernet framing).
437 */
438 p->dlt_list = (u_int *) malloc(sizeof(u_int) * 2);
439 /*
440 * If that fails, just leave the list empty.
441 */
442 if (p->dlt_list != NULL) {
443 p->dlt_list[0] = DLT_EN10MB;
444 p->dlt_list[1] = DLT_DOCSIS;
445 p->dlt_count = 2;
446 }
447
448 p->read_op = pcap_read_snit;
449 p->inject_op = pcap_inject_snit;
450 p->setfilter_op = install_bpf_program; /* no kernel filtering */
451 p->setdirection_op = NULL; /* Not implemented. */
452 p->set_datalink_op = NULL; /* can't change data link type */
453 p->getnonblock_op = pcap_getnonblock_fd;
454 p->setnonblock_op = pcap_setnonblock_fd;
455 p->stats_op = pcap_stats_snit;
456
457 return (0);
458 bad:
459 pcap_cleanup_live_common(p);
460 return (err);
461 }
462
463 pcap_t *
pcap_create_interface(const char * device _U_,char * ebuf)464 pcap_create_interface(const char *device _U_, char *ebuf)
465 {
466 pcap_t *p;
467
468 p = pcap_create_common(ebuf, sizeof (struct pcap_snit));
469 if (p == NULL)
470 return (NULL);
471
472 p->activate_op = pcap_activate_snit;
473 return (p);
474 }
475
476 /*
477 * XXX - there's probably a NIOCBIND error that means "that device
478 * doesn't support NIT"; if so, we should try an NIOCBIND and use that.
479 */
480 static int
can_be_bound(const char * name _U_)481 can_be_bound(const char *name _U_)
482 {
483 return (1);
484 }
485
486 static int
get_if_flags(const char * name _U_,bpf_u_int32 * flags _U_,char * errbuf _U_)487 get_if_flags(const char *name _U_, bpf_u_int32 *flags _U_, char *errbuf _U_)
488 {
489 /*
490 * Nothing we can do.
491 * XXX - is there a way to find out whether an adapter has
492 * something plugged into it?
493 */
494 return (0);
495 }
496
497 int
pcap_platform_finddevs(pcap_if_list_t * devlistp,char * errbuf)498 pcap_platform_finddevs(pcap_if_list_t *devlistp, char *errbuf)
499 {
500 return (pcap_findalldevs_interfaces(devlistp, errbuf, can_be_bound,
501 get_if_flags));
502 }
503
504 /*
505 * Libpcap version string.
506 */
507 const char *
pcap_lib_version(void)508 pcap_lib_version(void)
509 {
510 return (PCAP_VERSION_STRING);
511 }
512