1 /*
2 * ng_bpf.c
3 */
4
5 /*-
6 * Copyright (c) 1999 Whistle Communications, Inc.
7 * All rights reserved.
8 *
9 * Subject to the following obligations and disclaimer of warranty, use and
10 * redistribution of this software, in source or object code forms, with or
11 * without modifications are expressly permitted by Whistle Communications;
12 * provided, however, that:
13 * 1. Any and all reproductions of the source or object code must include the
14 * copyright notice above and the following disclaimer of warranties; and
15 * 2. No rights are granted, in any manner or form, to use Whistle
16 * Communications, Inc. trademarks, including the mark "WHISTLE
17 * COMMUNICATIONS" on advertising, endorsements, or otherwise except as
18 * such appears in the above copyright notice or in the software.
19 *
20 * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
21 * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
22 * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
23 * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
24 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
25 * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
26 * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
27 * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
28 * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
29 * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
30 * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
31 * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
32 * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
35 * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
36 * OF SUCH DAMAGE.
37 *
38 * Author: Archie Cobbs <archie@freebsd.org>
39 *
40 * $FreeBSD: src/sys/netgraph/ng_bpf.c,v 1.24 2008/02/04 19:26:53 mav Exp $
41 * $Whistle: ng_bpf.c,v 1.3 1999/12/03 20:30:23 archie Exp $
42 */
43
44 /*
45 * BPF NETGRAPH NODE TYPE
46 *
47 * This node type accepts any number of hook connections. With each hook
48 * is associated a bpf(4) filter program, and two hook names (each possibly
49 * the empty string). Incoming packets are compared against the filter;
50 * matching packets are delivered out the first named hook (or dropped if
51 * the empty string), and non-matching packets are delivered out the second
52 * named hook (or dropped if the empty string).
53 *
54 * Each hook also keeps statistics about how many packets have matched, etc.
55 */
56
57 #include <sys/param.h>
58 #include <sys/systm.h>
59 #include <sys/errno.h>
60 #include <sys/kernel.h>
61 #include <sys/malloc.h>
62 #include <sys/mbuf.h>
63
64 #include <net/bpf.h>
65 #ifdef BPF_JITTER
66 #include <net/bpf_jitter.h>
67 #endif
68
69 #include <netgraph7/ng_message.h>
70 #include <netgraph7/netgraph.h>
71 #include <netgraph7/ng_parse.h>
72 #include "ng_bpf.h"
73
74 #ifdef NG_SEPARATE_MALLOC
75 MALLOC_DEFINE(M_NETGRAPH_BPF, "netgraph_bpf", "netgraph bpf node ");
76 #else
77 #define M_NETGRAPH_BPF M_NETGRAPH
78 #endif
79
80 #define ERROUT(x) do { error = (x); goto done; } while (0)
81
82 /* Per hook private info */
83 struct ng_bpf_hookinfo {
84 hook_p hook;
85 hook_p match;
86 hook_p nomatch;
87 struct ng_bpf_hookprog *prog;
88 #ifdef BPF_JITTER
89 bpf_jit_filter *jit_prog;
90 #endif
91 struct ng_bpf_hookstat stats;
92 };
93 typedef struct ng_bpf_hookinfo *hinfo_p;
94
95 /* Netgraph methods */
96 static ng_constructor_t ng_bpf_constructor;
97 static ng_rcvmsg_t ng_bpf_rcvmsg;
98 static ng_shutdown_t ng_bpf_shutdown;
99 static ng_newhook_t ng_bpf_newhook;
100 static ng_rcvdata_t ng_bpf_rcvdata;
101 static ng_disconnect_t ng_bpf_disconnect;
102
103 /* Internal helper functions */
104 static int ng_bpf_setprog(hook_p hook, const struct ng_bpf_hookprog *hp);
105
106 /* Parse type for one struct bfp_insn */
107 static const struct ng_parse_struct_field ng_bpf_insn_type_fields[] = {
108 { "code", &ng_parse_hint16_type },
109 { "jt", &ng_parse_uint8_type },
110 { "jf", &ng_parse_uint8_type },
111 { "k", &ng_parse_uint32_type },
112 { NULL }
113 };
114 static const struct ng_parse_type ng_bpf_insn_type = {
115 &ng_parse_struct_type,
116 &ng_bpf_insn_type_fields
117 };
118
119 /* Parse type for the field 'bpf_prog' in struct ng_bpf_hookprog */
120 static int
ng_bpf_hookprogary_getLength(const struct ng_parse_type * type,const u_char * start,const u_char * buf)121 ng_bpf_hookprogary_getLength(const struct ng_parse_type *type,
122 const u_char *start, const u_char *buf)
123 {
124 const struct ng_bpf_hookprog *hp;
125
126 hp = (const struct ng_bpf_hookprog *)
127 (buf - __offsetof(struct ng_bpf_hookprog, bpf_prog));
128 return hp->bpf_prog_len;
129 }
130
131 static const struct ng_parse_array_info ng_bpf_hookprogary_info = {
132 &ng_bpf_insn_type,
133 &ng_bpf_hookprogary_getLength,
134 NULL
135 };
136 static const struct ng_parse_type ng_bpf_hookprogary_type = {
137 &ng_parse_array_type,
138 &ng_bpf_hookprogary_info
139 };
140
141 /* Parse type for struct ng_bpf_hookprog */
142 static const struct ng_parse_struct_field ng_bpf_hookprog_type_fields[]
143 = NG_BPF_HOOKPROG_TYPE_INFO(&ng_bpf_hookprogary_type);
144 static const struct ng_parse_type ng_bpf_hookprog_type = {
145 &ng_parse_struct_type,
146 &ng_bpf_hookprog_type_fields
147 };
148
149 /* Parse type for struct ng_bpf_hookstat */
150 static const struct ng_parse_struct_field ng_bpf_hookstat_type_fields[]
151 = NG_BPF_HOOKSTAT_TYPE_INFO;
152 static const struct ng_parse_type ng_bpf_hookstat_type = {
153 &ng_parse_struct_type,
154 &ng_bpf_hookstat_type_fields
155 };
156
157 /* List of commands and how to convert arguments to/from ASCII */
158 static const struct ng_cmdlist ng_bpf_cmdlist[] = {
159 {
160 NGM_BPF_COOKIE,
161 NGM_BPF_SET_PROGRAM,
162 "setprogram",
163 &ng_bpf_hookprog_type,
164 NULL
165 },
166 {
167 NGM_BPF_COOKIE,
168 NGM_BPF_GET_PROGRAM,
169 "getprogram",
170 &ng_parse_hookbuf_type,
171 &ng_bpf_hookprog_type
172 },
173 {
174 NGM_BPF_COOKIE,
175 NGM_BPF_GET_STATS,
176 "getstats",
177 &ng_parse_hookbuf_type,
178 &ng_bpf_hookstat_type
179 },
180 {
181 NGM_BPF_COOKIE,
182 NGM_BPF_CLR_STATS,
183 "clrstats",
184 &ng_parse_hookbuf_type,
185 NULL
186 },
187 {
188 NGM_BPF_COOKIE,
189 NGM_BPF_GETCLR_STATS,
190 "getclrstats",
191 &ng_parse_hookbuf_type,
192 &ng_bpf_hookstat_type
193 },
194 { 0 }
195 };
196
197 /* Netgraph type descriptor */
198 static struct ng_type typestruct = {
199 .version = NG_ABI_VERSION,
200 .name = NG_BPF_NODE_TYPE,
201 .constructor = ng_bpf_constructor,
202 .rcvmsg = ng_bpf_rcvmsg,
203 .shutdown = ng_bpf_shutdown,
204 .newhook = ng_bpf_newhook,
205 .rcvdata = ng_bpf_rcvdata,
206 .disconnect = ng_bpf_disconnect,
207 .cmdlist = ng_bpf_cmdlist,
208 };
209 NETGRAPH_INIT(bpf, &typestruct);
210
211 /* Default BPF program for a hook that matches nothing */
212 static const struct ng_bpf_hookprog ng_bpf_default_prog = {
213 { '\0' }, /* to be filled in at hook creation time */
214 { '\0' },
215 { '\0' },
216 1,
217 { BPF_STMT(BPF_RET+BPF_K, 0) }
218 };
219
220 /*
221 * Node constructor
222 *
223 * We don't keep any per-node private data
224 * We go via the hooks.
225 */
226 static int
ng_bpf_constructor(node_p node)227 ng_bpf_constructor(node_p node)
228 {
229 NG_NODE_SET_PRIVATE(node, NULL);
230 return (0);
231 }
232
233 /*
234 * Callback functions to be used by NG_NODE_FOREACH_HOOK() macro.
235 */
236 static int
ng_bpf_addrefs(hook_p hook,void * arg)237 ng_bpf_addrefs(hook_p hook, void* arg)
238 {
239 hinfo_p hip = NG_HOOK_PRIVATE(hook);
240 hook_p h = (hook_p)arg;
241
242 if (strcmp(hip->prog->ifMatch, NG_HOOK_NAME(h)) == 0)
243 hip->match = h;
244 if (strcmp(hip->prog->ifNotMatch, NG_HOOK_NAME(h)) == 0)
245 hip->nomatch = h;
246 return (1);
247 }
248
249 static int
ng_bpf_remrefs(hook_p hook,void * arg)250 ng_bpf_remrefs(hook_p hook, void* arg)
251 {
252 hinfo_p hip = NG_HOOK_PRIVATE(hook);
253 hook_p h = (hook_p)arg;
254
255 if (hip->match == h)
256 hip->match = NULL;
257 if (hip->nomatch == h)
258 hip->nomatch = NULL;
259 return (1);
260 }
261
262 /*
263 * Add a hook
264 */
265 static int
ng_bpf_newhook(node_p node,hook_p hook,const char * name)266 ng_bpf_newhook(node_p node, hook_p hook, const char *name)
267 {
268 hinfo_p hip;
269 hook_p tmp;
270 int error;
271
272 /* Create hook private structure */
273 hip = kmalloc(sizeof(*hip), M_NETGRAPH_BPF,
274 M_WAITOK | M_NULLOK | M_ZERO);
275 if (hip == NULL)
276 return (ENOMEM);
277 hip->hook = hook;
278 NG_HOOK_SET_PRIVATE(hook, hip);
279
280 /* Add our reference into other hooks data. */
281 NG_NODE_FOREACH_HOOK(node, ng_bpf_addrefs, hook, tmp);
282
283 /* Attach the default BPF program */
284 if ((error = ng_bpf_setprog(hook, &ng_bpf_default_prog)) != 0) {
285 kfree(hip, M_NETGRAPH_BPF);
286 NG_HOOK_SET_PRIVATE(hook, NULL);
287 return (error);
288 }
289
290 /* Set hook name */
291 strlcpy(hip->prog->thisHook, name, sizeof(hip->prog->thisHook));
292 return (0);
293 }
294
295 /*
296 * Receive a control message
297 */
298 static int
ng_bpf_rcvmsg(node_p node,item_p item,hook_p lasthook)299 ng_bpf_rcvmsg(node_p node, item_p item, hook_p lasthook)
300 {
301 struct ng_mesg *msg;
302 struct ng_mesg *resp = NULL;
303 int error = 0;
304
305 NGI_GET_MSG(item, msg);
306 switch (msg->header.typecookie) {
307 case NGM_BPF_COOKIE:
308 switch (msg->header.cmd) {
309 case NGM_BPF_SET_PROGRAM:
310 {
311 struct ng_bpf_hookprog *const
312 hp = (struct ng_bpf_hookprog *)msg->data;
313 hook_p hook;
314
315 /* Sanity check */
316 if (msg->header.arglen < sizeof(*hp)
317 || msg->header.arglen
318 != NG_BPF_HOOKPROG_SIZE(hp->bpf_prog_len))
319 ERROUT(EINVAL);
320
321 /* Find hook */
322 if ((hook = ng_findhook(node, hp->thisHook)) == NULL)
323 ERROUT(ENOENT);
324
325 /* Set new program */
326 if ((error = ng_bpf_setprog(hook, hp)) != 0)
327 ERROUT(error);
328 break;
329 }
330
331 case NGM_BPF_GET_PROGRAM:
332 {
333 struct ng_bpf_hookprog *hp;
334 hook_p hook;
335
336 /* Sanity check */
337 if (msg->header.arglen == 0)
338 ERROUT(EINVAL);
339 msg->data[msg->header.arglen - 1] = '\0';
340
341 /* Find hook */
342 if ((hook = ng_findhook(node, msg->data)) == NULL)
343 ERROUT(ENOENT);
344
345 /* Build response */
346 hp = ((hinfo_p)NG_HOOK_PRIVATE(hook))->prog;
347 NG_MKRESPONSE(resp, msg,
348 NG_BPF_HOOKPROG_SIZE(hp->bpf_prog_len), M_WAITOK | M_NULLOK);
349 if (resp == NULL)
350 ERROUT(ENOMEM);
351 bcopy(hp, resp->data,
352 NG_BPF_HOOKPROG_SIZE(hp->bpf_prog_len));
353 break;
354 }
355
356 case NGM_BPF_GET_STATS:
357 case NGM_BPF_CLR_STATS:
358 case NGM_BPF_GETCLR_STATS:
359 {
360 struct ng_bpf_hookstat *stats;
361 hook_p hook;
362
363 /* Sanity check */
364 if (msg->header.arglen == 0)
365 ERROUT(EINVAL);
366 msg->data[msg->header.arglen - 1] = '\0';
367
368 /* Find hook */
369 if ((hook = ng_findhook(node, msg->data)) == NULL)
370 ERROUT(ENOENT);
371 stats = &((hinfo_p)NG_HOOK_PRIVATE(hook))->stats;
372
373 /* Build response (if desired) */
374 if (msg->header.cmd != NGM_BPF_CLR_STATS) {
375 NG_MKRESPONSE(resp,
376 msg, sizeof(*stats), M_WAITOK | M_NULLOK);
377 if (resp == NULL)
378 ERROUT(ENOMEM);
379 bcopy(stats, resp->data, sizeof(*stats));
380 }
381
382 /* Clear stats (if desired) */
383 if (msg->header.cmd != NGM_BPF_GET_STATS)
384 bzero(stats, sizeof(*stats));
385 break;
386 }
387
388 default:
389 error = EINVAL;
390 break;
391 }
392 break;
393 default:
394 error = EINVAL;
395 break;
396 }
397 done:
398 NG_RESPOND_MSG(error, node, item, resp);
399 NG_FREE_MSG(msg);
400 return (error);
401 }
402
403 /*
404 * Receive data on a hook
405 *
406 * Apply the filter, and then drop or forward packet as appropriate.
407 */
408 static int
ng_bpf_rcvdata(hook_p hook,item_p item)409 ng_bpf_rcvdata(hook_p hook, item_p item)
410 {
411 const hinfo_p hip = NG_HOOK_PRIVATE(hook);
412 int totlen;
413 int needfree = 0, error = 0, usejit = 0;
414 u_char *data = NULL;
415 hinfo_p dhip;
416 hook_p dest;
417 u_int len;
418 struct mbuf *m;
419
420 m = NGI_M(item); /* 'item' still owns it.. we are peeking */
421 totlen = m->m_pkthdr.len;
422 /* Update stats on incoming hook. XXX Can we do 64 bits atomically? */
423 /* atomic_add_int64(&hip->stats.recvFrames, 1); */
424 /* atomic_add_int64(&hip->stats.recvOctets, totlen); */
425 hip->stats.recvFrames++;
426 hip->stats.recvOctets += totlen;
427
428 /* Don't call bpf_filter() with totlen == 0! */
429 if (totlen == 0) {
430 len = 0;
431 goto ready;
432 }
433
434 #ifdef BPF_JITTER
435 if (bpf_jitter_enable != 0 && hip->jit_prog != NULL)
436 usejit = 1;
437 #endif
438
439 /* Need to put packet in contiguous memory for bpf */
440 if (m->m_next != NULL && totlen > MHLEN) {
441 if (usejit) {
442 data = kmalloc(totlen, M_NETGRAPH_BPF, M_NOWAIT);
443 if (data == NULL) {
444 NG_FREE_ITEM(item);
445 return (ENOMEM);
446 }
447 needfree = 1;
448 m_copydata(m, 0, totlen, data);
449 }
450 } else {
451 if (m->m_next != NULL) {
452 NGI_M(item) = m = m_pullup(m, totlen);
453 if (m == NULL) {
454 NG_FREE_ITEM(item);
455 return (ENOBUFS);
456 }
457 }
458 data = mtod(m, u_char *);
459 }
460
461 /* Run packet through filter */
462 #ifdef BPF_JITTER
463 if (usejit)
464 len = (*(hip->jit_prog->func))(data, totlen, totlen);
465 else
466 #endif
467 if (data)
468 len = bpf_filter(hip->prog->bpf_prog, data, totlen, totlen);
469 else
470 len = bpf_filter(hip->prog->bpf_prog, (u_char *)m, totlen, 0);
471 if (needfree)
472 kfree(data, M_NETGRAPH_BPF);
473 ready:
474 /* See if we got a match and find destination hook */
475 if (len > 0) {
476
477 /* Update stats */
478 /* XXX atomically? */
479 hip->stats.recvMatchFrames++;
480 hip->stats.recvMatchOctets += totlen;
481
482 /* Truncate packet length if required by the filter */
483 /* Assume this never changes m */
484 if (len < totlen) {
485 m_adj(m, -(totlen - len));
486 totlen = len;
487 }
488 dest = hip->match;
489 } else
490 dest = hip->nomatch;
491 if (dest == NULL) {
492 NG_FREE_ITEM(item);
493 return (0);
494 }
495
496 /* Deliver frame out destination hook */
497 dhip = NG_HOOK_PRIVATE(dest);
498 dhip->stats.xmitOctets += totlen;
499 dhip->stats.xmitFrames++;
500 NG_FWD_ITEM_HOOK(error, item, dest);
501 return (error);
502 }
503
504 /*
505 * Shutdown processing
506 */
507 static int
ng_bpf_shutdown(node_p node)508 ng_bpf_shutdown(node_p node)
509 {
510 NG_NODE_UNREF(node);
511 return (0);
512 }
513
514 /*
515 * Hook disconnection
516 */
517 static int
ng_bpf_disconnect(hook_p hook)518 ng_bpf_disconnect(hook_p hook)
519 {
520 const node_p node = NG_HOOK_NODE(hook);
521 const hinfo_p hip = NG_HOOK_PRIVATE(hook);
522 hook_p tmp;
523
524 KASSERT(hip != NULL, ("%s: null info", __func__));
525
526 /* Remove our reference from other hooks data. */
527 NG_NODE_FOREACH_HOOK(node, ng_bpf_remrefs, hook, tmp);
528
529 kfree(hip->prog, M_NETGRAPH_BPF);
530 #ifdef BPF_JITTER
531 if (hip->jit_prog != NULL)
532 bpf_destroy_jit_filter(hip->jit_prog);
533 #endif
534 kfree(hip, M_NETGRAPH_BPF);
535 if ((NG_NODE_NUMHOOKS(node) == 0) &&
536 (NG_NODE_IS_VALID(node))) {
537 ng_rmnode_self(node);
538 }
539 return (0);
540 }
541
542 /************************************************************************
543 HELPER STUFF
544 ************************************************************************/
545
546 /*
547 * Set the BPF program associated with a hook
548 */
549 static int
ng_bpf_setprog(hook_p hook,const struct ng_bpf_hookprog * hp0)550 ng_bpf_setprog(hook_p hook, const struct ng_bpf_hookprog *hp0)
551 {
552 const hinfo_p hip = NG_HOOK_PRIVATE(hook);
553 struct ng_bpf_hookprog *hp;
554 #ifdef BPF_JITTER
555 bpf_jit_filter *jit_prog;
556 #endif
557 int size;
558
559 /* Check program for validity */
560 if (!bpf_validate(hp0->bpf_prog, hp0->bpf_prog_len))
561 return (EINVAL);
562
563 /* Make a copy of the program */
564 size = NG_BPF_HOOKPROG_SIZE(hp0->bpf_prog_len);
565 hp = kmalloc(size, M_NETGRAPH_BPF, M_NOWAIT);
566 if (hp == NULL)
567 return (ENOMEM);
568 bcopy(hp0, hp, size);
569 #ifdef BPF_JITTER
570 jit_prog = bpf_jitter(hp->bpf_prog, hp->bpf_prog_len);
571 #endif
572
573 /* Free previous program, if any, and assign new one */
574 if (hip->prog != NULL)
575 kfree(hip->prog, M_NETGRAPH_BPF);
576 hip->prog = hp;
577 #ifdef BPF_JITTER
578 if (hip->jit_prog != NULL)
579 bpf_destroy_jit_filter(hip->jit_prog);
580 hip->jit_prog = jit_prog;
581 #endif
582
583 /* Prepare direct references on target hooks. */
584 hip->match = ng_findhook(NG_HOOK_NODE(hook), hip->prog->ifMatch);
585 hip->nomatch = ng_findhook(NG_HOOK_NODE(hook), hip->prog->ifNotMatch);
586 return (0);
587 }
588