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, GUARANBPF, 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 *
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39 * $FreeBSD: head/sys/netgraph/ng_bpf.c 68876 2000-11-18 15:17:43Z dwmalone $
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39 * $FreeBSD: head/sys/netgraph/ng_bpf.c 69922 2000-12-12 18:52:14Z julian $ |
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#define OFFSETOF(s, e) ((char *)&((s *)0)->e - (char *)((s *)0)) 71 72#define ERROUT(x) do { error = (x); goto done; } while (0) 73 74/* Per hook private info */ 75struct ng_bpf_hookinfo { 76 node_p node; 77 hook_p hook; 78 struct ng_bpf_hookprog *prog; 79 struct ng_bpf_hookstat stats; 80}; 81typedef struct ng_bpf_hookinfo *hinfo_p; 82 83/* Netgraph methods */ 84static ng_constructor_t ng_bpf_constructor; 85static ng_rcvmsg_t ng_bpf_rcvmsg; 86static ng_shutdown_t ng_bpf_rmnode; 87static ng_newhook_t ng_bpf_newhook; 88static ng_rcvdata_t ng_bpf_rcvdata; 89static ng_disconnect_t ng_bpf_disconnect; 90 91/* Internal helper functions */ 92static int ng_bpf_setprog(hook_p hook, const struct ng_bpf_hookprog *hp); 93 94/* Parse type for one struct bfp_insn */ 95static const struct ng_parse_struct_info ng_bpf_insn_type_info = { 96 { 97 { "code", &ng_parse_hint16_type }, 98 { "jt", &ng_parse_uint8_type }, 99 { "jf", &ng_parse_uint8_type }, 100 { "k", &ng_parse_uint32_type }, 101 { NULL } 102 } 103}; 104static const struct ng_parse_type ng_bpf_insn_type = { 105 &ng_parse_struct_type, 106 &ng_bpf_insn_type_info 107}; 108 109/* Parse type for the field 'bpf_prog' in struct ng_bpf_hookprog */ 110static int 111ng_bpf_hookprogary_getLength(const struct ng_parse_type *type, 112 const u_char *start, const u_char *buf) 113{ 114 const struct ng_bpf_hookprog *hp; 115 116 hp = (const struct ng_bpf_hookprog *) 117 (buf - OFFSETOF(struct ng_bpf_hookprog, bpf_prog)); 118 return hp->bpf_prog_len; 119} 120 121static const struct ng_parse_array_info ng_bpf_hookprogary_info = { 122 &ng_bpf_insn_type, 123 &ng_bpf_hookprogary_getLength, 124 NULL 125}; 126static const struct ng_parse_type ng_bpf_hookprogary_type = { 127 &ng_parse_array_type, 128 &ng_bpf_hookprogary_info 129}; 130 131/* Parse type for struct ng_bpf_hookprog */ 132static const struct ng_parse_struct_info ng_bpf_hookprog_type_info 133 = NG_BPF_HOOKPROG_TYPE_INFO(&ng_bpf_hookprogary_type); 134static const struct ng_parse_type ng_bpf_hookprog_type = { 135 &ng_parse_struct_type, 136 &ng_bpf_hookprog_type_info 137}; 138 139/* Parse type for struct ng_bpf_hookstat */ 140static const struct ng_parse_struct_info 141 ng_bpf_hookstat_type_info = NG_BPF_HOOKSTAT_TYPE_INFO; 142static const struct ng_parse_type ng_bpf_hookstat_type = { 143 &ng_parse_struct_type, 144 &ng_bpf_hookstat_type_info 145}; 146 147/* List of commands and how to convert arguments to/from ASCII */ 148static const struct ng_cmdlist ng_bpf_cmdlist[] = { 149 { 150 NGM_BPF_COOKIE, 151 NGM_BPF_SET_PROGRAM, 152 "setprogram", 153 &ng_bpf_hookprog_type, 154 NULL 155 }, 156 { 157 NGM_BPF_COOKIE, 158 NGM_BPF_GET_PROGRAM, 159 "getprogram", 160 &ng_parse_hookbuf_type, 161 &ng_bpf_hookprog_type 162 }, 163 { 164 NGM_BPF_COOKIE, 165 NGM_BPF_GET_STATS, 166 "getstats", 167 &ng_parse_hookbuf_type, 168 &ng_bpf_hookstat_type 169 }, 170 { 171 NGM_BPF_COOKIE, 172 NGM_BPF_CLR_STATS, 173 "clrstats", 174 &ng_parse_hookbuf_type, 175 NULL 176 }, 177 { 178 NGM_BPF_COOKIE, 179 NGM_BPF_GETCLR_STATS, 180 "getclrstats", 181 &ng_parse_hookbuf_type, 182 &ng_bpf_hookstat_type 183 }, 184 { 0 } 185}; 186 187/* Netgraph type descriptor */ 188static struct ng_type typestruct = { 189 NG_VERSION, 190 NG_BPF_NODE_TYPE, 191 NULL, 192 ng_bpf_constructor, 193 ng_bpf_rcvmsg, 194 ng_bpf_rmnode, 195 ng_bpf_newhook, 196 NULL, 197 NULL, 198 ng_bpf_rcvdata,
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199 ng_bpf_rcvdata,
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199 ng_bpf_disconnect, 200 ng_bpf_cmdlist 201}; 202NETGRAPH_INIT(bpf, &typestruct); 203 204/* Default BPF program for a hook that matches nothing */ 205static const struct ng_bpf_hookprog ng_bpf_default_prog = { 206 { '\0' }, /* to be filled in at hook creation time */ 207 { '\0' }, 208 { '\0' }, 209 1, 210 { BPF_STMT(BPF_RET+BPF_K, 0) } 211}; 212 213/* 214 * Node constructor 215 * 216 * We don't keep any per-node private data 217 */ 218static int 219ng_bpf_constructor(node_p *nodep) 220{ 221 int error = 0; 222 223 if ((error = ng_make_node_common(&typestruct, nodep))) 224 return (error); 225 (*nodep)->private = NULL; 226 return (0); 227} 228 229/* 230 * Add a hook 231 */ 232static int 233ng_bpf_newhook(node_p node, hook_p hook, const char *name) 234{ 235 hinfo_p hip; 236 int error; 237 238 /* Create hook private structure */ 239 MALLOC(hip, hinfo_p, sizeof(*hip), M_NETGRAPH, M_NOWAIT | M_ZERO); 240 if (hip == NULL) 241 return (ENOMEM); 242 hip->hook = hook; 243 hook->private = hip; 244 hip->node = node; 245 246 /* Attach the default BPF program */ 247 if ((error = ng_bpf_setprog(hook, &ng_bpf_default_prog)) != 0) { 248 FREE(hip, M_NETGRAPH); 249 hook->private = NULL; 250 return (error); 251 } 252 253 /* Set hook name */ 254 strncpy(hip->prog->thisHook, name, sizeof(hip->prog->thisHook) - 1); 255 hip->prog->thisHook[sizeof(hip->prog->thisHook) - 1] = '\0'; 256 return (0); 257} 258 259/* 260 * Receive a control message 261 */ 262static int 263ng_bpf_rcvmsg(node_p node, struct ng_mesg *msg, const char *retaddr, 264 struct ng_mesg **rptr, hook_p lasthook) 265{ 266 struct ng_mesg *resp = NULL; 267 int error = 0; 268 269 switch (msg->header.typecookie) { 270 case NGM_BPF_COOKIE: 271 switch (msg->header.cmd) { 272 case NGM_BPF_SET_PROGRAM: 273 { 274 struct ng_bpf_hookprog *const 275 hp = (struct ng_bpf_hookprog *)msg->data; 276 hook_p hook; 277 278 /* Sanity check */ 279 if (msg->header.arglen < sizeof(*hp) 280 || msg->header.arglen 281 != NG_BPF_HOOKPROG_SIZE(hp->bpf_prog_len)) 282 ERROUT(EINVAL); 283 284 /* Find hook */ 285 if ((hook = ng_findhook(node, hp->thisHook)) == NULL) 286 ERROUT(ENOENT); 287 288 /* Set new program */ 289 if ((error = ng_bpf_setprog(hook, hp)) != 0) 290 ERROUT(error); 291 break; 292 } 293 294 case NGM_BPF_GET_PROGRAM: 295 { 296 struct ng_bpf_hookprog *hp; 297 hook_p hook; 298 299 /* Sanity check */ 300 if (msg->header.arglen == 0) 301 ERROUT(EINVAL); 302 msg->data[msg->header.arglen - 1] = '\0'; 303 304 /* Find hook */ 305 if ((hook = ng_findhook(node, msg->data)) == NULL) 306 ERROUT(ENOENT); 307 308 /* Build response */ 309 hp = ((hinfo_p)hook->private)->prog; 310 NG_MKRESPONSE(resp, msg, 311 NG_BPF_HOOKPROG_SIZE(hp->bpf_prog_len), M_NOWAIT); 312 if (resp == NULL) 313 ERROUT(ENOMEM); 314 bcopy(hp, resp->data, 315 NG_BPF_HOOKPROG_SIZE(hp->bpf_prog_len)); 316 break; 317 } 318 319 case NGM_BPF_GET_STATS: 320 case NGM_BPF_CLR_STATS: 321 case NGM_BPF_GETCLR_STATS: 322 { 323 struct ng_bpf_hookstat *stats; 324 hook_p hook; 325 326 /* Sanity check */ 327 if (msg->header.arglen == 0) 328 ERROUT(EINVAL); 329 msg->data[msg->header.arglen - 1] = '\0'; 330 331 /* Find hook */ 332 if ((hook = ng_findhook(node, msg->data)) == NULL) 333 ERROUT(ENOENT); 334 stats = &((hinfo_p)hook->private)->stats; 335 336 /* Build response (if desired) */ 337 if (msg->header.cmd != NGM_BPF_CLR_STATS) { 338 NG_MKRESPONSE(resp, 339 msg, sizeof(*stats), M_NOWAIT); 340 if (resp == NULL) 341 ERROUT(ENOMEM); 342 bcopy(stats, resp->data, sizeof(*stats)); 343 } 344 345 /* Clear stats (if desired) */ 346 if (msg->header.cmd != NGM_BPF_GET_STATS) 347 bzero(stats, sizeof(*stats)); 348 break; 349 } 350 351 default: 352 error = EINVAL; 353 break; 354 } 355 break; 356 default: 357 error = EINVAL; 358 break; 359 } 360 if (rptr) 361 *rptr = resp; 362 else if (resp) 363 FREE(resp, M_NETGRAPH); 364 365done: 366 FREE(msg, M_NETGRAPH); 367 return (error); 368} 369 370/* 371 * Receive data on a hook 372 * 373 * Apply the filter, and then drop or forward packet as appropriate. 374 */ 375static int 376ng_bpf_rcvdata(hook_p hook, struct mbuf *m, meta_p meta,
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378 struct mbuf **ret_m, meta_p *ret_meta)
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377 struct mbuf **ret_m, meta_p *ret_meta, struct ng_mesg **resp) |
378{ 379 const hinfo_p hip = hook->private; 380 int totlen = m->m_pkthdr.len; 381 int needfree = 0, error = 0; 382 u_char *data, buf[256]; 383 hinfo_p dhip; 384 hook_p dest; 385 u_int len; 386 387 /* Update stats on incoming hook */ 388 hip->stats.recvFrames++; 389 hip->stats.recvOctets += totlen; 390 391 /* Need to put packet in contiguous memory for bpf */ 392 if (m->m_next != NULL) { 393 if (totlen > sizeof(buf)) { 394 MALLOC(data, u_char *, totlen, M_NETGRAPH, M_NOWAIT); 395 if (data == NULL) { 396 NG_FREE_DATA(m, meta); 397 return (ENOMEM); 398 } 399 needfree = 1; 400 } else 401 data = buf; 402 m_copydata(m, 0, totlen, (caddr_t)data); 403 } else 404 data = mtod(m, u_char *); 405 406 /* Run packet through filter */ 407 len = bpf_filter(hip->prog->bpf_prog, data, totlen, totlen); 408 if (needfree) 409 FREE(data, M_NETGRAPH); 410 411 /* See if we got a match and find destination hook */ 412 if (len > 0) { 413 414 /* Update stats */ 415 hip->stats.recvMatchFrames++; 416 hip->stats.recvMatchOctets += totlen; 417 418 /* Truncate packet length if required by the filter */ 419 if (len < totlen) { 420 m_adj(m, -(totlen - len)); 421 totlen -= len; 422 } 423 dest = ng_findhook(hip->node, hip->prog->ifMatch); 424 } else 425 dest = ng_findhook(hip->node, hip->prog->ifNotMatch); 426 if (dest == NULL) { 427 NG_FREE_DATA(m, meta); 428 return (0); 429 } 430 431 /* Deliver frame out destination hook */ 432 dhip = (hinfo_p)dest->private; 433 dhip->stats.xmitOctets += totlen; 434 dhip->stats.xmitFrames++; 435 NG_SEND_DATA(error, dest, m, meta); 436 return (error); 437} 438 439/* 440 * Shutdown processing 441 */ 442static int 443ng_bpf_rmnode(node_p node) 444{ 445 node->flags |= NG_INVALID; 446 ng_cutlinks(node); 447 ng_unname(node); 448 ng_unref(node); 449 return (0); 450} 451 452/* 453 * Hook disconnection 454 */ 455static int 456ng_bpf_disconnect(hook_p hook) 457{ 458 const hinfo_p hip = hook->private; 459 460 KASSERT(hip != NULL, ("%s: null info", __FUNCTION__)); 461 FREE(hip->prog, M_NETGRAPH); 462 bzero(hip, sizeof(*hip)); 463 FREE(hip, M_NETGRAPH); 464 hook->private = NULL; /* for good measure */ 465 if (hook->node->numhooks == 0) 466 ng_rmnode(hook->node); 467 return (0); 468} 469 470/************************************************************************ 471 HELPER STUFF 472 ************************************************************************/ 473 474/* 475 * Set the BPF program associated with a hook 476 */ 477static int 478ng_bpf_setprog(hook_p hook, const struct ng_bpf_hookprog *hp0) 479{ 480 const hinfo_p hip = hook->private; 481 struct ng_bpf_hookprog *hp; 482 int size; 483 484 /* Check program for validity */ 485 if (!bpf_validate(hp0->bpf_prog, hp0->bpf_prog_len)) 486 return (EINVAL); 487 488 /* Make a copy of the program */ 489 size = NG_BPF_HOOKPROG_SIZE(hp0->bpf_prog_len); 490 MALLOC(hp, struct ng_bpf_hookprog *, size, M_NETGRAPH, M_NOWAIT); 491 if (hp == NULL) 492 return (ENOMEM); 493 bcopy(hp0, hp, size); 494 495 /* Free previous program, if any, and assign new one */ 496 if (hip->prog != NULL) 497 FREE(hip->prog, M_NETGRAPH); 498 hip->prog = hp; 499 return (0); 500} 501
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