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 * 39 * $FreeBSD: src/sys/netgraph/ng_bpf.c,v 1.2.4.4 2002/07/02 23:44:02 archie Exp $ 40 * $DragonFly: src/sys/netgraph/bpf/ng_bpf.c,v 1.3 2003/08/07 21:17:31 dillon 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 66 #include <netgraph/ng_message.h> 67 #include <netgraph/netgraph.h> 68 #include <netgraph/ng_parse.h> 69 #include "ng_bpf.h" 70 71 #define OFFSETOF(s, e) ((char *)&((s *)0)->e - (char *)((s *)0)) 72 73 #define ERROUT(x) do { error = (x); goto done; } while (0) 74 75 /* Per hook private info */ 76 struct ng_bpf_hookinfo { 77 node_p node; 78 hook_p hook; 79 struct ng_bpf_hookprog *prog; 80 struct ng_bpf_hookstat stats; 81 }; 82 typedef struct ng_bpf_hookinfo *hinfo_p; 83 84 /* Netgraph methods */ 85 static ng_constructor_t ng_bpf_constructor; 86 static ng_rcvmsg_t ng_bpf_rcvmsg; 87 static ng_shutdown_t ng_bpf_rmnode; 88 static ng_newhook_t ng_bpf_newhook; 89 static ng_rcvdata_t ng_bpf_rcvdata; 90 static ng_disconnect_t ng_bpf_disconnect; 91 92 /* Internal helper functions */ 93 static int ng_bpf_setprog(hook_p hook, const struct ng_bpf_hookprog *hp); 94 95 /* Parse type for one struct bfp_insn */ 96 static const struct ng_parse_struct_field ng_bpf_insn_type_fields[] = { 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 static const struct ng_parse_type ng_bpf_insn_type = { 104 &ng_parse_struct_type, 105 &ng_bpf_insn_type_fields 106 }; 107 108 /* Parse type for the field 'bpf_prog' in struct ng_bpf_hookprog */ 109 static int 110 ng_bpf_hookprogary_getLength(const struct ng_parse_type *type, 111 const u_char *start, const u_char *buf) 112 { 113 const struct ng_bpf_hookprog *hp; 114 115 hp = (const struct ng_bpf_hookprog *) 116 (buf - OFFSETOF(struct ng_bpf_hookprog, bpf_prog)); 117 return hp->bpf_prog_len; 118 } 119 120 static const struct ng_parse_array_info ng_bpf_hookprogary_info = { 121 &ng_bpf_insn_type, 122 &ng_bpf_hookprogary_getLength, 123 NULL 124 }; 125 static const struct ng_parse_type ng_bpf_hookprogary_type = { 126 &ng_parse_array_type, 127 &ng_bpf_hookprogary_info 128 }; 129 130 /* Parse type for struct ng_bpf_hookprog */ 131 static const struct ng_parse_struct_field ng_bpf_hookprog_type_fields[] 132 = NG_BPF_HOOKPROG_TYPE_INFO(&ng_bpf_hookprogary_type); 133 static const struct ng_parse_type ng_bpf_hookprog_type = { 134 &ng_parse_struct_type, 135 &ng_bpf_hookprog_type_fields 136 }; 137 138 /* Parse type for struct ng_bpf_hookstat */ 139 static const struct ng_parse_struct_field ng_bpf_hookstat_type_fields[] 140 = NG_BPF_HOOKSTAT_TYPE_INFO; 141 static const struct ng_parse_type ng_bpf_hookstat_type = { 142 &ng_parse_struct_type, 143 &ng_bpf_hookstat_type_fields 144 }; 145 146 /* List of commands and how to convert arguments to/from ASCII */ 147 static const struct ng_cmdlist ng_bpf_cmdlist[] = { 148 { 149 NGM_BPF_COOKIE, 150 NGM_BPF_SET_PROGRAM, 151 "setprogram", 152 &ng_bpf_hookprog_type, 153 NULL 154 }, 155 { 156 NGM_BPF_COOKIE, 157 NGM_BPF_GET_PROGRAM, 158 "getprogram", 159 &ng_parse_hookbuf_type, 160 &ng_bpf_hookprog_type 161 }, 162 { 163 NGM_BPF_COOKIE, 164 NGM_BPF_GET_STATS, 165 "getstats", 166 &ng_parse_hookbuf_type, 167 &ng_bpf_hookstat_type 168 }, 169 { 170 NGM_BPF_COOKIE, 171 NGM_BPF_CLR_STATS, 172 "clrstats", 173 &ng_parse_hookbuf_type, 174 NULL 175 }, 176 { 177 NGM_BPF_COOKIE, 178 NGM_BPF_GETCLR_STATS, 179 "getclrstats", 180 &ng_parse_hookbuf_type, 181 &ng_bpf_hookstat_type 182 }, 183 { 0 } 184 }; 185 186 /* Netgraph type descriptor */ 187 static struct ng_type typestruct = { 188 NG_VERSION, 189 NG_BPF_NODE_TYPE, 190 NULL, 191 ng_bpf_constructor, 192 ng_bpf_rcvmsg, 193 ng_bpf_rmnode, 194 ng_bpf_newhook, 195 NULL, 196 NULL, 197 ng_bpf_rcvdata, 198 ng_bpf_rcvdata, 199 ng_bpf_disconnect, 200 ng_bpf_cmdlist 201 }; 202 NETGRAPH_INIT(bpf, &typestruct); 203 204 /* Default BPF program for a hook that matches nothing */ 205 static 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 */ 218 static int 219 ng_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 */ 232 static int 233 ng_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); 240 if (hip == NULL) 241 return (ENOMEM); 242 bzero(hip, sizeof(*hip)); 243 hip->hook = hook; 244 hook->private = 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); 250 hook->private = 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, struct ng_mesg *msg, const char *retaddr, 265 struct ng_mesg **rptr) 266 { 267 struct ng_mesg *resp = NULL; 268 int error = 0; 269 270 switch (msg->header.typecookie) { 271 case NGM_BPF_COOKIE: 272 switch (msg->header.cmd) { 273 case NGM_BPF_SET_PROGRAM: 274 { 275 struct ng_bpf_hookprog *const 276 hp = (struct ng_bpf_hookprog *)msg->data; 277 hook_p hook; 278 279 /* Sanity check */ 280 if (msg->header.arglen < sizeof(*hp) 281 || msg->header.arglen 282 != NG_BPF_HOOKPROG_SIZE(hp->bpf_prog_len)) 283 ERROUT(EINVAL); 284 285 /* Find hook */ 286 if ((hook = ng_findhook(node, hp->thisHook)) == NULL) 287 ERROUT(ENOENT); 288 289 /* Set new program */ 290 if ((error = ng_bpf_setprog(hook, hp)) != 0) 291 ERROUT(error); 292 break; 293 } 294 295 case NGM_BPF_GET_PROGRAM: 296 { 297 struct ng_bpf_hookprog *hp; 298 hook_p hook; 299 300 /* Sanity check */ 301 if (msg->header.arglen == 0) 302 ERROUT(EINVAL); 303 msg->data[msg->header.arglen - 1] = '\0'; 304 305 /* Find hook */ 306 if ((hook = ng_findhook(node, msg->data)) == NULL) 307 ERROUT(ENOENT); 308 309 /* Build response */ 310 hp = ((hinfo_p)hook->private)->prog; 311 NG_MKRESPONSE(resp, msg, 312 NG_BPF_HOOKPROG_SIZE(hp->bpf_prog_len), M_NOWAIT); 313 if (resp == NULL) 314 ERROUT(ENOMEM); 315 bcopy(hp, resp->data, 316 NG_BPF_HOOKPROG_SIZE(hp->bpf_prog_len)); 317 break; 318 } 319 320 case NGM_BPF_GET_STATS: 321 case NGM_BPF_CLR_STATS: 322 case NGM_BPF_GETCLR_STATS: 323 { 324 struct ng_bpf_hookstat *stats; 325 hook_p hook; 326 327 /* Sanity check */ 328 if (msg->header.arglen == 0) 329 ERROUT(EINVAL); 330 msg->data[msg->header.arglen - 1] = '\0'; 331 332 /* Find hook */ 333 if ((hook = ng_findhook(node, msg->data)) == NULL) 334 ERROUT(ENOENT); 335 stats = &((hinfo_p)hook->private)->stats; 336 337 /* Build response (if desired) */ 338 if (msg->header.cmd != NGM_BPF_CLR_STATS) { 339 NG_MKRESPONSE(resp, 340 msg, sizeof(*stats), M_NOWAIT); 341 if (resp == NULL) 342 ERROUT(ENOMEM); 343 bcopy(stats, resp->data, sizeof(*stats)); 344 } 345 346 /* Clear stats (if desired) */ 347 if (msg->header.cmd != NGM_BPF_GET_STATS) 348 bzero(stats, sizeof(*stats)); 349 break; 350 } 351 352 default: 353 error = EINVAL; 354 break; 355 } 356 break; 357 default: 358 error = EINVAL; 359 break; 360 } 361 if (rptr) 362 *rptr = resp; 363 else if (resp) 364 FREE(resp, M_NETGRAPH); 365 366 done: 367 FREE(msg, M_NETGRAPH); 368 return (error); 369 } 370 371 /* 372 * Receive data on a hook 373 * 374 * Apply the filter, and then drop or forward packet as appropriate. 375 */ 376 static int 377 ng_bpf_rcvdata(hook_p hook, struct mbuf *m, meta_p meta) 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 */ 442 static int 443 ng_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 */ 455 static int 456 ng_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 */ 477 static int 478 ng_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 } 501 502