FreeBSD/Linux Kernel Cross Reference
sys/netgraph/ng_bpf.c
1
2 /*
3 * ng_bpf.c
4 *
5 * Copyright (c) 1999 Whistle Communications, Inc.
6 * All rights reserved.
7 *
8 * Subject to the following obligations and disclaimer of warranty, use and
9 * redistribution of this software, in source or object code forms, with or
10 * without modifications are expressly permitted by Whistle Communications;
11 * provided, however, that:
12 * 1. Any and all reproductions of the source or object code must include the
13 * copyright notice above and the following disclaimer of warranties; and
14 * 2. No rights are granted, in any manner or form, to use Whistle
15 * Communications, Inc. trademarks, including the mark "WHISTLE
16 * COMMUNICATIONS" on advertising, endorsements, or otherwise except as
17 * such appears in the above copyright notice or in the software.
18 *
19 * THIS SOFTWARE IS BEING PROVIDED BY WHISTLE COMMUNICATIONS "AS IS", AND
20 * TO THE MAXIMUM EXTENT PERMITTED BY LAW, WHISTLE COMMUNICATIONS MAKES NO
21 * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS SOFTWARE,
22 * INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED WARRANTIES OF
23 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT.
24 * WHISTLE COMMUNICATIONS DOES NOT WARRANT, GUARANTEE, OR MAKE ANY
25 * REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS OF THE USE OF THIS
26 * SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY, RELIABILITY OR OTHERWISE.
27 * IN NO EVENT SHALL WHISTLE COMMUNICATIONS BE LIABLE FOR ANY DAMAGES
28 * RESULTING FROM OR ARISING OUT OF ANY USE OF THIS SOFTWARE, INCLUDING
29 * WITHOUT LIMITATION, ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY,
30 * PUNITIVE, OR CONSEQUENTIAL DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR
31 * SERVICES, LOSS OF USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER ANY
32 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
33 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
34 * THIS SOFTWARE, EVEN IF WHISTLE COMMUNICATIONS IS ADVISED OF THE POSSIBILITY
35 * OF SUCH DAMAGE.
36 *
37 * Author: Archie Cobbs <archie@freebsd.org>
38 *
39 * $FreeBSD: releng/5.1/sys/netgraph/ng_bpf.c 97685 2002-05-31 23:48:03Z archie $
40 * $Whistle: ng_bpf.c,v 1.3 1999/12/03 20:30:23 archie Exp $
41 */
42
43 /*
44 * BPF NETGRAPH NODE TYPE
45 *
46 * This node type accepts any number of hook connections. With each hook
47 * is associated a bpf(4) filter program, and two hook names (each possibly
48 * the empty string). Incoming packets are compared against the filter;
49 * matching packets are delivered out the first named hook (or dropped if
50 * the empty string), and non-matching packets are delivered out the second
51 * named hook (or dropped if the empty string).
52 *
53 * Each hook also keeps statistics about how many packets have matched, etc.
54 */
55
56 #include <sys/param.h>
57 #include <sys/systm.h>
58 #include <sys/errno.h>
59 #include <sys/kernel.h>
60 #include <sys/malloc.h>
61 #include <sys/mbuf.h>
62
63 #include <net/bpf.h>
64
65 #include <netgraph/ng_message.h>
66 #include <netgraph/netgraph.h>
67 #include <netgraph/ng_parse.h>
68 #include <netgraph/ng_bpf.h>
69
70 #ifdef NG_SEPARATE_MALLOC
71 MALLOC_DEFINE(M_NETGRAPH_BPF, "netgraph_bpf", "netgraph bpf node ");
72 #else
73 #define M_NETGRAPH_BPF M_NETGRAPH
74 #endif
75
76 #define OFFSETOF(s, e) ((char *)&((s *)0)->e - (char *)((s *)0))
77
78 #define ERROUT(x) do { error = (x); goto done; } while (0)
79
80 /* Per hook private info */
81 struct ng_bpf_hookinfo {
82 node_p node;
83 hook_p hook;
84 struct ng_bpf_hookprog *prog;
85 struct ng_bpf_hookstat stats;
86 };
87 typedef struct ng_bpf_hookinfo *hinfo_p;
88
89 /* Netgraph methods */
90 static ng_constructor_t ng_bpf_constructor;
91 static ng_rcvmsg_t ng_bpf_rcvmsg;
92 static ng_shutdown_t ng_bpf_shutdown;
93 static ng_newhook_t ng_bpf_newhook;
94 static ng_rcvdata_t ng_bpf_rcvdata;
95 static ng_disconnect_t ng_bpf_disconnect;
96
97 /* Internal helper functions */
98 static int ng_bpf_setprog(hook_p hook, const struct ng_bpf_hookprog *hp);
99
100 /* Parse type for one struct bfp_insn */
101 static const struct ng_parse_struct_field ng_bpf_insn_type_fields[] = {
102 { "code", &ng_parse_hint16_type },
103 { "jt", &ng_parse_uint8_type },
104 { "jf", &ng_parse_uint8_type },
105 { "k", &ng_parse_uint32_type },
106 { NULL }
107 };
108 static const struct ng_parse_type ng_bpf_insn_type = {
109 &ng_parse_struct_type,
110 &ng_bpf_insn_type_fields
111 };
112
113 /* Parse type for the field 'bpf_prog' in struct ng_bpf_hookprog */
114 static int
115 ng_bpf_hookprogary_getLength(const struct ng_parse_type *type,
116 const u_char *start, const u_char *buf)
117 {
118 const struct ng_bpf_hookprog *hp;
119
120 hp = (const struct ng_bpf_hookprog *)
121 (buf - OFFSETOF(struct ng_bpf_hookprog, bpf_prog));
122 return hp->bpf_prog_len;
123 }
124
125 static const struct ng_parse_array_info ng_bpf_hookprogary_info = {
126 &ng_bpf_insn_type,
127 &ng_bpf_hookprogary_getLength,
128 NULL
129 };
130 static const struct ng_parse_type ng_bpf_hookprogary_type = {
131 &ng_parse_array_type,
132 &ng_bpf_hookprogary_info
133 };
134
135 /* Parse type for struct ng_bpf_hookprog */
136 static const struct ng_parse_struct_field ng_bpf_hookprog_type_fields[]
137 = NG_BPF_HOOKPROG_TYPE_INFO(&ng_bpf_hookprogary_type);
138 static const struct ng_parse_type ng_bpf_hookprog_type = {
139 &ng_parse_struct_type,
140 &ng_bpf_hookprog_type_fields
141 };
142
143 /* Parse type for struct ng_bpf_hookstat */
144 static const struct ng_parse_struct_field ng_bpf_hookstat_type_fields[]
145 = NG_BPF_HOOKSTAT_TYPE_INFO;
146 static const struct ng_parse_type ng_bpf_hookstat_type = {
147 &ng_parse_struct_type,
148 &ng_bpf_hookstat_type_fields
149 };
150
151 /* List of commands and how to convert arguments to/from ASCII */
152 static const struct ng_cmdlist ng_bpf_cmdlist[] = {
153 {
154 NGM_BPF_COOKIE,
155 NGM_BPF_SET_PROGRAM,
156 "setprogram",
157 &ng_bpf_hookprog_type,
158 NULL
159 },
160 {
161 NGM_BPF_COOKIE,
162 NGM_BPF_GET_PROGRAM,
163 "getprogram",
164 &ng_parse_hookbuf_type,
165 &ng_bpf_hookprog_type
166 },
167 {
168 NGM_BPF_COOKIE,
169 NGM_BPF_GET_STATS,
170 "getstats",
171 &ng_parse_hookbuf_type,
172 &ng_bpf_hookstat_type
173 },
174 {
175 NGM_BPF_COOKIE,
176 NGM_BPF_CLR_STATS,
177 "clrstats",
178 &ng_parse_hookbuf_type,
179 NULL
180 },
181 {
182 NGM_BPF_COOKIE,
183 NGM_BPF_GETCLR_STATS,
184 "getclrstats",
185 &ng_parse_hookbuf_type,
186 &ng_bpf_hookstat_type
187 },
188 { 0 }
189 };
190
191 /* Netgraph type descriptor */
192 static struct ng_type typestruct = {
193 NG_ABI_VERSION,
194 NG_BPF_NODE_TYPE,
195 NULL,
196 ng_bpf_constructor,
197 ng_bpf_rcvmsg,
198 ng_bpf_shutdown,
199 ng_bpf_newhook,
200 NULL,
201 NULL,
202 ng_bpf_rcvdata,
203 ng_bpf_disconnect,
204 ng_bpf_cmdlist
205 };
206 NETGRAPH_INIT(bpf, &typestruct);
207
208 /* Default BPF program for a hook that matches nothing */
209 static const struct ng_bpf_hookprog ng_bpf_default_prog = {
210 { '\0' }, /* to be filled in at hook creation time */
211 { '\0' },
212 { '\0' },
213 1,
214 { BPF_STMT(BPF_RET+BPF_K, 0) }
215 };
216
217 /*
218 * Node constructor
219 *
220 * We don't keep any per-node private data
221 * We go via the hooks.
222 */
223 static int
224 ng_bpf_constructor(node_p node)
225 {
226 NG_NODE_SET_PRIVATE(node, NULL);
227 return (0);
228 }
229
230 /*
231 * Add a hook
232 */
233 static int
234 ng_bpf_newhook(node_p node, hook_p hook, const char *name)
235 {
236 hinfo_p hip;
237 int error;
238
239 /* Create hook private structure */
240 MALLOC(hip, hinfo_p, sizeof(*hip), M_NETGRAPH_BPF, M_NOWAIT | M_ZERO);
241 if (hip == NULL)
242 return (ENOMEM);
243 hip->hook = hook;
244 NG_HOOK_SET_PRIVATE(hook, hip);
245 hip->node = node;
246
247 /* Attach the default BPF program */
248 if ((error = ng_bpf_setprog(hook, &ng_bpf_default_prog)) != 0) {
249 FREE(hip, M_NETGRAPH_BPF);
250 NG_HOOK_SET_PRIVATE(hook, NULL);
251 return (error);
252 }
253
254 /* Set hook name */
255 strncpy(hip->prog->thisHook, name, sizeof(hip->prog->thisHook) - 1);
256 hip->prog->thisHook[sizeof(hip->prog->thisHook) - 1] = '\0';
257 return (0);
258 }
259
260 /*
261 * Receive a control message
262 */
263 static int
264 ng_bpf_rcvmsg(node_p node, item_p item, hook_p lasthook)
265 {
266 struct ng_mesg *msg;
267 struct ng_mesg *resp = NULL;
268 int error = 0;
269
270 NGI_GET_MSG(item, msg);
271 switch (msg->header.typecookie) {
272 case NGM_BPF_COOKIE:
273 switch (msg->header.cmd) {
274 case NGM_BPF_SET_PROGRAM:
275 {
276 struct ng_bpf_hookprog *const
277 hp = (struct ng_bpf_hookprog *)msg->data;
278 hook_p hook;
279
280 /* Sanity check */
281 if (msg->header.arglen < sizeof(*hp)
282 || msg->header.arglen
283 != NG_BPF_HOOKPROG_SIZE(hp->bpf_prog_len))
284 ERROUT(EINVAL);
285
286 /* Find hook */
287 if ((hook = ng_findhook(node, hp->thisHook)) == NULL)
288 ERROUT(ENOENT);
289
290 /* Set new program */
291 if ((error = ng_bpf_setprog(hook, hp)) != 0)
292 ERROUT(error);
293 break;
294 }
295
296 case NGM_BPF_GET_PROGRAM:
297 {
298 struct ng_bpf_hookprog *hp;
299 hook_p hook;
300
301 /* Sanity check */
302 if (msg->header.arglen == 0)
303 ERROUT(EINVAL);
304 msg->data[msg->header.arglen - 1] = '\0';
305
306 /* Find hook */
307 if ((hook = ng_findhook(node, msg->data)) == NULL)
308 ERROUT(ENOENT);
309
310 /* Build response */
311 hp = ((hinfo_p)NG_HOOK_PRIVATE(hook))->prog;
312 NG_MKRESPONSE(resp, msg,
313 NG_BPF_HOOKPROG_SIZE(hp->bpf_prog_len), M_NOWAIT);
314 if (resp == NULL)
315 ERROUT(ENOMEM);
316 bcopy(hp, resp->data,
317 NG_BPF_HOOKPROG_SIZE(hp->bpf_prog_len));
318 break;
319 }
320
321 case NGM_BPF_GET_STATS:
322 case NGM_BPF_CLR_STATS:
323 case NGM_BPF_GETCLR_STATS:
324 {
325 struct ng_bpf_hookstat *stats;
326 hook_p hook;
327
328 /* Sanity check */
329 if (msg->header.arglen == 0)
330 ERROUT(EINVAL);
331 msg->data[msg->header.arglen - 1] = '\0';
332
333 /* Find hook */
334 if ((hook = ng_findhook(node, msg->data)) == NULL)
335 ERROUT(ENOENT);
336 stats = &((hinfo_p)NG_HOOK_PRIVATE(hook))->stats;
337
338 /* Build response (if desired) */
339 if (msg->header.cmd != NGM_BPF_CLR_STATS) {
340 NG_MKRESPONSE(resp,
341 msg, sizeof(*stats), M_NOWAIT);
342 if (resp == NULL)
343 ERROUT(ENOMEM);
344 bcopy(stats, resp->data, sizeof(*stats));
345 }
346
347 /* Clear stats (if desired) */
348 if (msg->header.cmd != NGM_BPF_GET_STATS)
349 bzero(stats, sizeof(*stats));
350 break;
351 }
352
353 default:
354 error = EINVAL;
355 break;
356 }
357 break;
358 default:
359 error = EINVAL;
360 break;
361 }
362 done:
363 NG_RESPOND_MSG(error, node, item, resp);
364 NG_FREE_MSG(msg);
365 return (error);
366 }
367
368 /*
369 * Receive data on a hook
370 *
371 * Apply the filter, and then drop or forward packet as appropriate.
372 */
373 static int
374 ng_bpf_rcvdata(hook_p hook, item_p item)
375 {
376 const hinfo_p hip = NG_HOOK_PRIVATE(hook);
377 int totlen;
378 int needfree = 0, error = 0;
379 u_char *data, buf[256];
380 hinfo_p dhip;
381 hook_p dest;
382 u_int len;
383 struct mbuf *m;
384
385 m = NGI_M(item); /* 'item' still owns it.. we are peeking */
386 totlen = m->m_pkthdr.len;
387 /* Update stats on incoming hook. XXX Can we do 64 bits atomically? */
388 /* atomic_add_int64(&hip->stats.recvFrames, 1); */
389 /* atomic_add_int64(&hip->stats.recvOctets, totlen); */
390 hip->stats.recvFrames++;
391 hip->stats.recvOctets += totlen;
392
393 /* Need to put packet in contiguous memory for bpf */
394 if (m->m_next != NULL) {
395 if (totlen > sizeof(buf)) {
396 MALLOC(data, u_char *, totlen, M_NETGRAPH_BPF, M_NOWAIT);
397 if (data == NULL) {
398 NG_FREE_ITEM(item);
399 return (ENOMEM);
400 }
401 needfree = 1;
402 } else
403 data = buf;
404 m_copydata(m, 0, totlen, (caddr_t)data);
405 } else
406 data = mtod(m, u_char *);
407
408 /* Run packet through filter */
409 len = bpf_filter(hip->prog->bpf_prog, data, totlen, totlen);
410 if (needfree)
411 FREE(data, M_NETGRAPH_BPF);
412
413 /* See if we got a match and find destination hook */
414 if (len > 0) {
415
416 /* Update stats */
417 /* XXX atomically? */
418 hip->stats.recvMatchFrames++;
419 hip->stats.recvMatchOctets += totlen;
420
421 /* Truncate packet length if required by the filter */
422 /* Assume this never changes m */
423 if (len < totlen) {
424 m_adj(m, -(totlen - len));
425 totlen -= len;
426 }
427 dest = ng_findhook(hip->node, hip->prog->ifMatch);
428 } else
429 dest = ng_findhook(hip->node, hip->prog->ifNotMatch);
430 if (dest == NULL) {
431 NG_FREE_ITEM(item);
432 return (0);
433 }
434
435 /* Deliver frame out destination hook */
436 dhip = NG_HOOK_PRIVATE(dest);
437 dhip->stats.xmitOctets += totlen;
438 dhip->stats.xmitFrames++;
439 NG_FWD_ITEM_HOOK(error, item, dest);
440 return (error);
441 }
442
443 /*
444 * Shutdown processing
445 */
446 static int
447 ng_bpf_shutdown(node_p node)
448 {
449 NG_NODE_UNREF(node);
450 return (0);
451 }
452
453 /*
454 * Hook disconnection
455 */
456 static int
457 ng_bpf_disconnect(hook_p hook)
458 {
459 const hinfo_p hip = NG_HOOK_PRIVATE(hook);
460
461 KASSERT(hip != NULL, ("%s: null info", __func__));
462 FREE(hip->prog, M_NETGRAPH_BPF);
463 bzero(hip, sizeof(*hip));
464 FREE(hip, M_NETGRAPH_BPF);
465 NG_HOOK_SET_PRIVATE(hook, NULL); /* for good measure */
466 if ((NG_NODE_NUMHOOKS(NG_HOOK_NODE(hook)) == 0)
467 && (NG_NODE_IS_VALID(NG_HOOK_NODE(hook)))) {
468 ng_rmnode_self(NG_HOOK_NODE(hook));
469 }
470 return (0);
471 }
472
473 /************************************************************************
474 HELPER STUFF
475 ************************************************************************/
476
477 /*
478 * Set the BPF program associated with a hook
479 */
480 static int
481 ng_bpf_setprog(hook_p hook, const struct ng_bpf_hookprog *hp0)
482 {
483 const hinfo_p hip = NG_HOOK_PRIVATE(hook);
484 struct ng_bpf_hookprog *hp;
485 int size;
486
487 /* Check program for validity */
488 if (!bpf_validate(hp0->bpf_prog, hp0->bpf_prog_len))
489 return (EINVAL);
490
491 /* Make a copy of the program */
492 size = NG_BPF_HOOKPROG_SIZE(hp0->bpf_prog_len);
493 MALLOC(hp, struct ng_bpf_hookprog *, size, M_NETGRAPH_BPF, M_NOWAIT);
494 if (hp == NULL)
495 return (ENOMEM);
496 bcopy(hp0, hp, size);
497
498 /* Free previous program, if any, and assign new one */
499 if (hip->prog != NULL)
500 FREE(hip->prog, M_NETGRAPH_BPF);
501 hip->prog = hp;
502 return (0);
503 }
504
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