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 1.5 2008/01/05 14:02:39 swildner 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 | 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 */ 262 static int 263 ng_bpf_rcvmsg(node_p node, struct ng_mesg *msg, const char *retaddr, 264 struct ng_mesg **rptr) 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); 364 365 done: 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 */ 375 static int 376 ng_bpf_rcvdata(hook_p hook, struct mbuf *m, meta_p meta) 377 { 378 const hinfo_p hip = hook->private; 379 int totlen = m->m_pkthdr.len; 380 int needfree = 0, error = 0; 381 u_char *data, buf[256]; 382 hinfo_p dhip; 383 hook_p dest; 384 u_int len; 385 386 /* Update stats on incoming hook */ 387 hip->stats.recvFrames++; 388 hip->stats.recvOctets += totlen; 389 390 /* Need to put packet in contiguous memory for bpf */ 391 if (m->m_next != NULL) { 392 if (totlen > sizeof(buf)) { 393 MALLOC(data, u_char *, totlen, M_NETGRAPH, M_NOWAIT); 394 if (data == NULL) { 395 NG_FREE_DATA(m, meta); 396 return (ENOMEM); 397 } 398 needfree = 1; 399 } else 400 data = buf; 401 m_copydata(m, 0, totlen, (caddr_t)data); 402 } else 403 data = mtod(m, u_char *); 404 405 /* Run packet through filter */ 406 len = bpf_filter(hip->prog->bpf_prog, data, totlen, totlen); 407 if (needfree) 408 FREE(data, M_NETGRAPH); 409 410 /* See if we got a match and find destination hook */ 411 if (len > 0) { 412 413 /* Update stats */ 414 hip->stats.recvMatchFrames++; 415 hip->stats.recvMatchOctets += totlen; 416 417 /* Truncate packet length if required by the filter */ 418 if (len < totlen) { 419 m_adj(m, -(totlen - len)); 420 totlen -= len; 421 } 422 dest = ng_findhook(hip->node, hip->prog->ifMatch); 423 } else 424 dest = ng_findhook(hip->node, hip->prog->ifNotMatch); 425 if (dest == NULL) { 426 NG_FREE_DATA(m, meta); 427 return (0); 428 } 429 430 /* Deliver frame out destination hook */ 431 dhip = (hinfo_p)dest->private; 432 dhip->stats.xmitOctets += totlen; 433 dhip->stats.xmitFrames++; 434 NG_SEND_DATA(error, dest, m, meta); 435 return (error); 436 } 437 438 /* 439 * Shutdown processing 440 */ 441 static int 442 ng_bpf_rmnode(node_p node) 443 { 444 node->flags |= NG_INVALID; 445 ng_cutlinks(node); 446 ng_unname(node); 447 ng_unref(node); 448 return (0); 449 } 450 451 /* 452 * Hook disconnection 453 */ 454 static int 455 ng_bpf_disconnect(hook_p hook) 456 { 457 const hinfo_p hip = hook->private; 458 459 KASSERT(hip != NULL, ("%s: null info", __func__)); 460 FREE(hip->prog, M_NETGRAPH); 461 bzero(hip, sizeof(*hip)); 462 FREE(hip, M_NETGRAPH); 463 hook->private = NULL; /* for good measure */ 464 if (hook->node->numhooks == 0) 465 ng_rmnode(hook->node); 466 return (0); 467 } 468 469 /************************************************************************ 470 HELPER STUFF 471 ************************************************************************/ 472 473 /* 474 * Set the BPF program associated with a hook 475 */ 476 static int 477 ng_bpf_setprog(hook_p hook, const struct ng_bpf_hookprog *hp0) 478 { 479 const hinfo_p hip = hook->private; 480 struct ng_bpf_hookprog *hp; 481 int size; 482 483 /* Check program for validity */ 484 if (!bpf_validate(hp0->bpf_prog, hp0->bpf_prog_len)) 485 return (EINVAL); 486 487 /* Make a copy of the program */ 488 size = NG_BPF_HOOKPROG_SIZE(hp0->bpf_prog_len); 489 MALLOC(hp, struct ng_bpf_hookprog *, size, M_NETGRAPH, M_NOWAIT); 490 if (hp == NULL) 491 return (ENOMEM); 492 bcopy(hp0, hp, size); 493 494 /* Free previous program, if any, and assign new one */ 495 if (hip->prog != NULL) 496 FREE(hip->prog, M_NETGRAPH); 497 hip->prog = hp; 498 return (0); 499 } 500 501