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