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[dragonfly.git] / sys / netgraph7 / ng_bpf.c
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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 $
5a975a3d 41 * $DragonFly: src/sys/netgraph7/ng_bpf.c,v 1.2 2008/06/26 23:05:35 dillon Exp $
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42 * $Whistle: ng_bpf.c,v 1.3 1999/12/03 20:30:23 archie Exp $
43 */
44
45/*
46 * BPF NETGRAPH NODE TYPE
47 *
48 * This node type accepts any number of hook connections. With each hook
49 * is associated a bpf(4) filter program, and two hook names (each possibly
50 * the empty string). Incoming packets are compared against the filter;
51 * matching packets are delivered out the first named hook (or dropped if
52 * the empty string), and non-matching packets are delivered out the second
53 * named hook (or dropped if the empty string).
54 *
55 * Each hook also keeps statistics about how many packets have matched, etc.
56 */
57
58#include "opt_bpf.h"
59
60#include <sys/param.h>
61#include <sys/systm.h>
62#include <sys/errno.h>
63#include <sys/kernel.h>
64#include <sys/malloc.h>
65#include <sys/mbuf.h>
66
67#include <net/bpf.h>
68#ifdef BPF_JITTER
69#include <net/bpf_jitter.h>
70#endif
71
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72#include "ng_message.h"
73#include "netgraph.h"
74#include "ng_parse.h"
75#include "ng_bpf.h"
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76
77#ifdef NG_SEPARATE_MALLOC
78MALLOC_DEFINE(M_NETGRAPH_BPF, "netgraph_bpf", "netgraph bpf node ");
79#else
80#define M_NETGRAPH_BPF M_NETGRAPH
81#endif
82
83#define OFFSETOF(s, e) ((char *)&((s *)0)->e - (char *)((s *)0))
84
85#define ERROUT(x) do { error = (x); goto done; } while (0)
86
87/* Per hook private info */
88struct ng_bpf_hookinfo {
89 hook_p hook;
90 hook_p match;
91 hook_p nomatch;
92 struct ng_bpf_hookprog *prog;
93#ifdef BPF_JITTER
94 bpf_jit_filter *jit_prog;
95#endif
96 struct ng_bpf_hookstat stats;
97};
98typedef struct ng_bpf_hookinfo *hinfo_p;
99
100/* Netgraph methods */
101static ng_constructor_t ng_bpf_constructor;
102static ng_rcvmsg_t ng_bpf_rcvmsg;
103static ng_shutdown_t ng_bpf_shutdown;
104static ng_newhook_t ng_bpf_newhook;
105static ng_rcvdata_t ng_bpf_rcvdata;
106static ng_disconnect_t ng_bpf_disconnect;
107
108/* Internal helper functions */
109static int ng_bpf_setprog(hook_p hook, const struct ng_bpf_hookprog *hp);
110
111/* Parse type for one struct bfp_insn */
112static const struct ng_parse_struct_field ng_bpf_insn_type_fields[] = {
113 { "code", &ng_parse_hint16_type },
114 { "jt", &ng_parse_uint8_type },
115 { "jf", &ng_parse_uint8_type },
116 { "k", &ng_parse_uint32_type },
117 { NULL }
118};
119static const struct ng_parse_type ng_bpf_insn_type = {
120 &ng_parse_struct_type,
121 &ng_bpf_insn_type_fields
122};
123
124/* Parse type for the field 'bpf_prog' in struct ng_bpf_hookprog */
125static int
126ng_bpf_hookprogary_getLength(const struct ng_parse_type *type,
127 const u_char *start, const u_char *buf)
128{
129 const struct ng_bpf_hookprog *hp;
130
131 hp = (const struct ng_bpf_hookprog *)
132 (buf - OFFSETOF(struct ng_bpf_hookprog, bpf_prog));
133 return hp->bpf_prog_len;
134}
135
136static const struct ng_parse_array_info ng_bpf_hookprogary_info = {
137 &ng_bpf_insn_type,
138 &ng_bpf_hookprogary_getLength,
139 NULL
140};
141static const struct ng_parse_type ng_bpf_hookprogary_type = {
142 &ng_parse_array_type,
143 &ng_bpf_hookprogary_info
144};
145
146/* Parse type for struct ng_bpf_hookprog */
147static const struct ng_parse_struct_field ng_bpf_hookprog_type_fields[]
148 = NG_BPF_HOOKPROG_TYPE_INFO(&ng_bpf_hookprogary_type);
149static const struct ng_parse_type ng_bpf_hookprog_type = {
150 &ng_parse_struct_type,
151 &ng_bpf_hookprog_type_fields
152};
153
154/* Parse type for struct ng_bpf_hookstat */
155static const struct ng_parse_struct_field ng_bpf_hookstat_type_fields[]
156 = NG_BPF_HOOKSTAT_TYPE_INFO;
157static const struct ng_parse_type ng_bpf_hookstat_type = {
158 &ng_parse_struct_type,
159 &ng_bpf_hookstat_type_fields
160};
161
162/* List of commands and how to convert arguments to/from ASCII */
163static const struct ng_cmdlist ng_bpf_cmdlist[] = {
164 {
165 NGM_BPF_COOKIE,
166 NGM_BPF_SET_PROGRAM,
167 "setprogram",
168 &ng_bpf_hookprog_type,
169 NULL
170 },
171 {
172 NGM_BPF_COOKIE,
173 NGM_BPF_GET_PROGRAM,
174 "getprogram",
175 &ng_parse_hookbuf_type,
176 &ng_bpf_hookprog_type
177 },
178 {
179 NGM_BPF_COOKIE,
180 NGM_BPF_GET_STATS,
181 "getstats",
182 &ng_parse_hookbuf_type,
183 &ng_bpf_hookstat_type
184 },
185 {
186 NGM_BPF_COOKIE,
187 NGM_BPF_CLR_STATS,
188 "clrstats",
189 &ng_parse_hookbuf_type,
190 NULL
191 },
192 {
193 NGM_BPF_COOKIE,
194 NGM_BPF_GETCLR_STATS,
195 "getclrstats",
196 &ng_parse_hookbuf_type,
197 &ng_bpf_hookstat_type
198 },
199 { 0 }
200};
201
202/* Netgraph type descriptor */
203static struct ng_type typestruct = {
204 .version = NG_ABI_VERSION,
205 .name = NG_BPF_NODE_TYPE,
206 .constructor = ng_bpf_constructor,
207 .rcvmsg = ng_bpf_rcvmsg,
208 .shutdown = ng_bpf_shutdown,
209 .newhook = ng_bpf_newhook,
210 .rcvdata = ng_bpf_rcvdata,
211 .disconnect = ng_bpf_disconnect,
212 .cmdlist = ng_bpf_cmdlist,
213};
214NETGRAPH_INIT(bpf, &typestruct);
215
216/* Default BPF program for a hook that matches nothing */
217static const struct ng_bpf_hookprog ng_bpf_default_prog = {
218 { '\0' }, /* to be filled in at hook creation time */
219 { '\0' },
220 { '\0' },
221 1,
222 { BPF_STMT(BPF_RET+BPF_K, 0) }
223};
224
225/*
226 * Node constructor
227 *
228 * We don't keep any per-node private data
229 * We go via the hooks.
230 */
231static int
232ng_bpf_constructor(node_p node)
233{
234 NG_NODE_SET_PRIVATE(node, NULL);
235 return (0);
236}
237
238/*
239 * Callback functions to be used by NG_NODE_FOREACH_HOOK() macro.
240 */
241static int
242ng_bpf_addrefs(hook_p hook, void* arg)
243{
244 hinfo_p hip = NG_HOOK_PRIVATE(hook);
245 hook_p h = (hook_p)arg;
246
247 if (strcmp(hip->prog->ifMatch, NG_HOOK_NAME(h)) == 0)
248 hip->match = h;
249 if (strcmp(hip->prog->ifNotMatch, NG_HOOK_NAME(h)) == 0)
250 hip->nomatch = h;
251 return (1);
252}
253
254static int
255ng_bpf_remrefs(hook_p hook, void* arg)
256{
257 hinfo_p hip = NG_HOOK_PRIVATE(hook);
258 hook_p h = (hook_p)arg;
259
260 if (hip->match == h)
261 hip->match = NULL;
262 if (hip->nomatch == h)
263 hip->nomatch = NULL;
264 return (1);
265}
266
267/*
268 * Add a hook
269 */
270static int
271ng_bpf_newhook(node_p node, hook_p hook, const char *name)
272{
273 hinfo_p hip;
274 hook_p tmp;
275 int error;
276
277 /* Create hook private structure */
5a975a3d 278 MALLOC(hip, hinfo_p, sizeof(*hip), M_NETGRAPH_BPF, M_WAITOK | M_NULLOK | M_ZERO);
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279 if (hip == NULL)
280 return (ENOMEM);
281 hip->hook = hook;
282 NG_HOOK_SET_PRIVATE(hook, hip);
283
284 /* Add our reference into other hooks data. */
285 NG_NODE_FOREACH_HOOK(node, ng_bpf_addrefs, hook, tmp);
286
287 /* Attach the default BPF program */
288 if ((error = ng_bpf_setprog(hook, &ng_bpf_default_prog)) != 0) {
289 FREE(hip, M_NETGRAPH_BPF);
290 NG_HOOK_SET_PRIVATE(hook, NULL);
291 return (error);
292 }
293
294 /* Set hook name */
295 strlcpy(hip->prog->thisHook, name, sizeof(hip->prog->thisHook));
296 return (0);
297}
298
299/*
300 * Receive a control message
301 */
302static int
303ng_bpf_rcvmsg(node_p node, item_p item, hook_p lasthook)
304{
305 struct ng_mesg *msg;
306 struct ng_mesg *resp = NULL;
307 int error = 0;
308
309 NGI_GET_MSG(item, msg);
310 switch (msg->header.typecookie) {
311 case NGM_BPF_COOKIE:
312 switch (msg->header.cmd) {
313 case NGM_BPF_SET_PROGRAM:
314 {
315 struct ng_bpf_hookprog *const
316 hp = (struct ng_bpf_hookprog *)msg->data;
317 hook_p hook;
318
319 /* Sanity check */
320 if (msg->header.arglen < sizeof(*hp)
321 || msg->header.arglen
322 != NG_BPF_HOOKPROG_SIZE(hp->bpf_prog_len))
323 ERROUT(EINVAL);
324
325 /* Find hook */
326 if ((hook = ng_findhook(node, hp->thisHook)) == NULL)
327 ERROUT(ENOENT);
328
329 /* Set new program */
330 if ((error = ng_bpf_setprog(hook, hp)) != 0)
331 ERROUT(error);
332 break;
333 }
334
335 case NGM_BPF_GET_PROGRAM:
336 {
337 struct ng_bpf_hookprog *hp;
338 hook_p hook;
339
340 /* Sanity check */
341 if (msg->header.arglen == 0)
342 ERROUT(EINVAL);
343 msg->data[msg->header.arglen - 1] = '\0';
344
345 /* Find hook */
346 if ((hook = ng_findhook(node, msg->data)) == NULL)
347 ERROUT(ENOENT);
348
349 /* Build response */
350 hp = ((hinfo_p)NG_HOOK_PRIVATE(hook))->prog;
351 NG_MKRESPONSE(resp, msg,
5a975a3d 352 NG_BPF_HOOKPROG_SIZE(hp->bpf_prog_len), M_WAITOK | M_NULLOK);
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353 if (resp == NULL)
354 ERROUT(ENOMEM);
355 bcopy(hp, resp->data,
356 NG_BPF_HOOKPROG_SIZE(hp->bpf_prog_len));
357 break;
358 }
359
360 case NGM_BPF_GET_STATS:
361 case NGM_BPF_CLR_STATS:
362 case NGM_BPF_GETCLR_STATS:
363 {
364 struct ng_bpf_hookstat *stats;
365 hook_p hook;
366
367 /* Sanity check */
368 if (msg->header.arglen == 0)
369 ERROUT(EINVAL);
370 msg->data[msg->header.arglen - 1] = '\0';
371
372 /* Find hook */
373 if ((hook = ng_findhook(node, msg->data)) == NULL)
374 ERROUT(ENOENT);
375 stats = &((hinfo_p)NG_HOOK_PRIVATE(hook))->stats;
376
377 /* Build response (if desired) */
378 if (msg->header.cmd != NGM_BPF_CLR_STATS) {
379 NG_MKRESPONSE(resp,
5a975a3d 380 msg, sizeof(*stats), M_WAITOK | M_NULLOK);
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381 if (resp == NULL)
382 ERROUT(ENOMEM);
383 bcopy(stats, resp->data, sizeof(*stats));
384 }
385
386 /* Clear stats (if desired) */
387 if (msg->header.cmd != NGM_BPF_GET_STATS)
388 bzero(stats, sizeof(*stats));
389 break;
390 }
391
392 default:
393 error = EINVAL;
394 break;
395 }
396 break;
397 default:
398 error = EINVAL;
399 break;
400 }
401done:
402 NG_RESPOND_MSG(error, node, item, resp);
403 NG_FREE_MSG(msg);
404 return (error);
405}
406
407/*
408 * Receive data on a hook
409 *
410 * Apply the filter, and then drop or forward packet as appropriate.
411 */
412static int
413ng_bpf_rcvdata(hook_p hook, item_p item)
414{
415 const hinfo_p hip = NG_HOOK_PRIVATE(hook);
416 int totlen;
417 int needfree = 0, error = 0, usejit = 0;
418 u_char *data = NULL;
419 hinfo_p dhip;
420 hook_p dest;
421 u_int len;
422 struct mbuf *m;
423
424 m = NGI_M(item); /* 'item' still owns it.. we are peeking */
425 totlen = m->m_pkthdr.len;
426 /* Update stats on incoming hook. XXX Can we do 64 bits atomically? */
427 /* atomic_add_int64(&hip->stats.recvFrames, 1); */
428 /* atomic_add_int64(&hip->stats.recvOctets, totlen); */
429 hip->stats.recvFrames++;
430 hip->stats.recvOctets += totlen;
431
432 /* Don't call bpf_filter() with totlen == 0! */
433 if (totlen == 0) {
434 len = 0;
435 goto ready;
436 }
437
438#ifdef BPF_JITTER
439 if (bpf_jitter_enable != 0 && hip->jit_prog != NULL)
440 usejit = 1;
441#endif
442
443 /* Need to put packet in contiguous memory for bpf */
444 if (m->m_next != NULL && totlen > MHLEN) {
445 if (usejit) {
446 MALLOC(data, u_char *, totlen, M_NETGRAPH_BPF, M_NOWAIT);
447 if (data == NULL) {
448 NG_FREE_ITEM(item);
449 return (ENOMEM);
450 }
451 needfree = 1;
452 m_copydata(m, 0, totlen, (caddr_t)data);
453 }
454 } else {
455 if (m->m_next != NULL) {
456 NGI_M(item) = m = m_pullup(m, totlen);
457 if (m == NULL) {
458 NG_FREE_ITEM(item);
459 return (ENOBUFS);
460 }
461 }
462 data = mtod(m, u_char *);
463 }
464
465 /* Run packet through filter */
466#ifdef BPF_JITTER
467 if (usejit)
468 len = (*(hip->jit_prog->func))(data, totlen, totlen);
469 else
470#endif
471 if (data)
472 len = bpf_filter(hip->prog->bpf_prog, data, totlen, totlen);
473 else
474 len = bpf_filter(hip->prog->bpf_prog, (u_char *)m, totlen, 0);
475 if (needfree)
476 FREE(data, M_NETGRAPH_BPF);
477ready:
478 /* See if we got a match and find destination hook */
479 if (len > 0) {
480
481 /* Update stats */
482 /* XXX atomically? */
483 hip->stats.recvMatchFrames++;
484 hip->stats.recvMatchOctets += totlen;
485
486 /* Truncate packet length if required by the filter */
487 /* Assume this never changes m */
488 if (len < totlen) {
489 m_adj(m, -(totlen - len));
490 totlen = len;
491 }
492 dest = hip->match;
493 } else
494 dest = hip->nomatch;
495 if (dest == NULL) {
496 NG_FREE_ITEM(item);
497 return (0);
498 }
499
500 /* Deliver frame out destination hook */
501 dhip = NG_HOOK_PRIVATE(dest);
502 dhip->stats.xmitOctets += totlen;
503 dhip->stats.xmitFrames++;
504 NG_FWD_ITEM_HOOK(error, item, dest);
505 return (error);
506}
507
508/*
509 * Shutdown processing
510 */
511static int
512ng_bpf_shutdown(node_p node)
513{
514 NG_NODE_UNREF(node);
515 return (0);
516}
517
518/*
519 * Hook disconnection
520 */
521static int
522ng_bpf_disconnect(hook_p hook)
523{
524 const node_p node = NG_HOOK_NODE(hook);
525 const hinfo_p hip = NG_HOOK_PRIVATE(hook);
526 hook_p tmp;
527
528 KASSERT(hip != NULL, ("%s: null info", __func__));
529
530 /* Remove our reference from other hooks data. */
531 NG_NODE_FOREACH_HOOK(node, ng_bpf_remrefs, hook, tmp);
532
533 FREE(hip->prog, M_NETGRAPH_BPF);
534#ifdef BPF_JITTER
535 if (hip->jit_prog != NULL)
536 bpf_destroy_jit_filter(hip->jit_prog);
537#endif
538 FREE(hip, M_NETGRAPH_BPF);
539 if ((NG_NODE_NUMHOOKS(node) == 0) &&
540 (NG_NODE_IS_VALID(node))) {
541 ng_rmnode_self(node);
542 }
543 return (0);
544}
545
546/************************************************************************
547 HELPER STUFF
548 ************************************************************************/
549
550/*
551 * Set the BPF program associated with a hook
552 */
553static int
554ng_bpf_setprog(hook_p hook, const struct ng_bpf_hookprog *hp0)
555{
556 const hinfo_p hip = NG_HOOK_PRIVATE(hook);
557 struct ng_bpf_hookprog *hp;
558#ifdef BPF_JITTER
559 bpf_jit_filter *jit_prog;
560#endif
561 int size;
562
563 /* Check program for validity */
564 if (!bpf_validate(hp0->bpf_prog, hp0->bpf_prog_len))
565 return (EINVAL);
566
567 /* Make a copy of the program */
568 size = NG_BPF_HOOKPROG_SIZE(hp0->bpf_prog_len);
569 MALLOC(hp, struct ng_bpf_hookprog *, size, M_NETGRAPH_BPF, M_NOWAIT);
570 if (hp == NULL)
571 return (ENOMEM);
572 bcopy(hp0, hp, size);
573#ifdef BPF_JITTER
574 jit_prog = bpf_jitter(hp->bpf_prog, hp->bpf_prog_len);
575#endif
576
577 /* Free previous program, if any, and assign new one */
578 if (hip->prog != NULL)
579 FREE(hip->prog, M_NETGRAPH_BPF);
580 hip->prog = hp;
581#ifdef BPF_JITTER
582 if (hip->jit_prog != NULL)
583 bpf_destroy_jit_filter(hip->jit_prog);
584 hip->jit_prog = jit_prog;
585#endif
586
587 /* Prepare direct references on target hooks. */
588 hip->match = ng_findhook(NG_HOOK_NODE(hook), hip->prog->ifMatch);
589 hip->nomatch = ng_findhook(NG_HOOK_NODE(hook), hip->prog->ifNotMatch);
590 return (0);
591}