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 * $FreeBSD$ 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 */ 75 struct ng_bpf_hookinfo { 76 node_p node; 77 hook_p hook; 78 struct ng_bpf_hookprog *prog; 79 struct ng_bpf_hookstat stats; 80 }; 81 typedef struct ng_bpf_hookinfo *hinfo_p; 82 83 /* Netgraph methods */ 84 static ng_constructor_t ng_bpf_constructor; 85 static ng_rcvmsg_t ng_bpf_rcvmsg; 86 static ng_shutdown_t ng_bpf_shutdown; 87 static ng_newhook_t ng_bpf_newhook; 88 static ng_rcvdata_t ng_bpf_rcvdata; 89 static ng_disconnect_t ng_bpf_disconnect; 90 91 /* Internal helper functions */ 92 static int ng_bpf_setprog(hook_p hook, const struct ng_bpf_hookprog *hp); 93 94 /* Parse type for one struct bfp_insn */ 95 static 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 }; 104 static 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 */ 110 static int 111 ng_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 } 120 121 static const struct ng_parse_array_info ng_bpf_hookprogary_info = { 122 &ng_bpf_insn_type, 123 &ng_bpf_hookprogary_getLength, 124 NULL 125 }; 126 static 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 */ 132 static const struct ng_parse_struct_info ng_bpf_hookprog_type_info 133 = NG_BPF_HOOKPROG_TYPE_INFO(&ng_bpf_hookprogary_type); 134 static 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 */ 140 static const struct ng_parse_struct_info 141 ng_bpf_hookstat_type_info = NG_BPF_HOOKSTAT_TYPE_INFO; 142 static 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 */ 148 static 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 */ 188 static struct ng_type typestruct = { 189 NG_ABI_VERSION, 190 NG_BPF_NODE_TYPE, 191 NULL, 192 ng_bpf_constructor, 193 ng_bpf_rcvmsg, 194 ng_bpf_shutdown, 195 ng_bpf_newhook, 196 NULL, 197 NULL, 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 * We go via the hooks. 218 */ 219 static int 220 ng_bpf_constructor(node_p node) 221 { 222 node->private = NULL; 223 return (0); 224 } 225 226 /* 227 * Add a hook 228 */ 229 static int 230 ng_bpf_newhook(node_p node, hook_p hook, const char *name) 231 { 232 hinfo_p hip; 233 int error; 234 235 /* Create hook private structure */ 236 MALLOC(hip, hinfo_p, sizeof(*hip), M_NETGRAPH, M_NOWAIT | M_ZERO); 237 if (hip == NULL) 238 return (ENOMEM); 239 hip->hook = hook; 240 hook->private = hip; 241 hip->node = node; 242 243 /* Attach the default BPF program */ 244 if ((error = ng_bpf_setprog(hook, &ng_bpf_default_prog)) != 0) { 245 FREE(hip, M_NETGRAPH); 246 hook->private = NULL; 247 return (error); 248 } 249 250 /* Set hook name */ 251 strncpy(hip->prog->thisHook, name, sizeof(hip->prog->thisHook) - 1); 252 hip->prog->thisHook[sizeof(hip->prog->thisHook) - 1] = '\0'; 253 return (0); 254 } 255 256 /* 257 * Receive a control message 258 */ 259 static int 260 ng_bpf_rcvmsg(node_p node, item_p item, hook_p lasthook) 261 { 262 struct ng_mesg *msg; 263 struct ng_mesg *resp = NULL; 264 int error = 0; 265 266 NGI_GET_MSG(item, msg); 267 switch (msg->header.typecookie) { 268 case NGM_BPF_COOKIE: 269 switch (msg->header.cmd) { 270 case NGM_BPF_SET_PROGRAM: 271 { 272 struct ng_bpf_hookprog *const 273 hp = (struct ng_bpf_hookprog *)msg->data; 274 hook_p hook; 275 276 /* Sanity check */ 277 if (msg->header.arglen < sizeof(*hp) 278 || msg->header.arglen 279 != NG_BPF_HOOKPROG_SIZE(hp->bpf_prog_len)) 280 ERROUT(EINVAL); 281 282 /* Find hook */ 283 if ((hook = ng_findhook(node, hp->thisHook)) == NULL) 284 ERROUT(ENOENT); 285 286 /* Set new program */ 287 if ((error = ng_bpf_setprog(hook, hp)) != 0) 288 ERROUT(error); 289 break; 290 } 291 292 case NGM_BPF_GET_PROGRAM: 293 { 294 struct ng_bpf_hookprog *hp; 295 hook_p hook; 296 297 /* Sanity check */ 298 if (msg->header.arglen == 0) 299 ERROUT(EINVAL); 300 msg->data[msg->header.arglen - 1] = '\0'; 301 302 /* Find hook */ 303 if ((hook = ng_findhook(node, msg->data)) == NULL) 304 ERROUT(ENOENT); 305 306 /* Build response */ 307 hp = ((hinfo_p)hook->private)->prog; 308 NG_MKRESPONSE(resp, msg, 309 NG_BPF_HOOKPROG_SIZE(hp->bpf_prog_len), M_NOWAIT); 310 if (resp == NULL) 311 ERROUT(ENOMEM); 312 bcopy(hp, resp->data, 313 NG_BPF_HOOKPROG_SIZE(hp->bpf_prog_len)); 314 break; 315 } 316 317 case NGM_BPF_GET_STATS: 318 case NGM_BPF_CLR_STATS: 319 case NGM_BPF_GETCLR_STATS: 320 { 321 struct ng_bpf_hookstat *stats; 322 hook_p hook; 323 324 /* Sanity check */ 325 if (msg->header.arglen == 0) 326 ERROUT(EINVAL); 327 msg->data[msg->header.arglen - 1] = '\0'; 328 329 /* Find hook */ 330 if ((hook = ng_findhook(node, msg->data)) == NULL) 331 ERROUT(ENOENT); 332 stats = &((hinfo_p)hook->private)->stats; 333 334 /* Build response (if desired) */ 335 if (msg->header.cmd != NGM_BPF_CLR_STATS) { 336 NG_MKRESPONSE(resp, 337 msg, sizeof(*stats), M_NOWAIT); 338 if (resp == NULL) 339 ERROUT(ENOMEM); 340 bcopy(stats, resp->data, sizeof(*stats)); 341 } 342 343 /* Clear stats (if desired) */ 344 if (msg->header.cmd != NGM_BPF_GET_STATS) 345 bzero(stats, sizeof(*stats)); 346 break; 347 } 348 349 default: 350 error = EINVAL; 351 break; 352 } 353 break; 354 default: 355 error = EINVAL; 356 break; 357 } 358 NG_RESPOND_MSG(error, node, item, resp); 359 done: 360 if (item) 361 NG_FREE_ITEM(item); 362 NG_FREE_MSG(msg); 363 return (error); 364 } 365 366 /* 367 * Receive data on a hook 368 * 369 * Apply the filter, and then drop or forward packet as appropriate. 370 */ 371 static int 372 ng_bpf_rcvdata(hook_p hook, item_p item) 373 { 374 const hinfo_p hip = hook->private; 375 int totlen; 376 int needfree = 0, error = 0; 377 u_char *data, buf[256]; 378 hinfo_p dhip; 379 hook_p dest; 380 u_int len; 381 struct mbuf *m; 382 383 m = NGI_M(item); /* 'item' still owns it.. we are peeking */ 384 totlen = m->m_pkthdr.len; 385 /* Update stats on incoming hook. XXX Can we do 64 bits atomically? */ 386 /* atomic_add_int64(&hip->stats.recvFrames, 1); */ 387 /* atomic_add_int64(&hip->stats.recvOctets, totlen); */ 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_ITEM(item); 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 /* XXX atomically? */ 416 hip->stats.recvMatchFrames++; 417 hip->stats.recvMatchOctets += totlen; 418 419 /* Truncate packet length if required by the filter */ 420 /* Assume this never changes m */ 421 if (len < totlen) { 422 m_adj(m, -(totlen - len)); 423 totlen -= len; 424 } 425 dest = ng_findhook(hip->node, hip->prog->ifMatch); 426 } else 427 dest = ng_findhook(hip->node, hip->prog->ifNotMatch); 428 if (dest == NULL) { 429 NG_FREE_ITEM(item); 430 return (0); 431 } 432 433 /* Deliver frame out destination hook */ 434 dhip = (hinfo_p)dest->private; 435 dhip->stats.xmitOctets += totlen; 436 dhip->stats.xmitFrames++; 437 NG_FWD_DATA(error, item, dest); 438 return (error); 439 } 440 441 /* 442 * Shutdown processing 443 */ 444 static int 445 ng_bpf_shutdown(node_p node) 446 { 447 node->flags |= NG_INVALID; 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 && ((hook->node->flags && NG_INVALID) == 0)) { 467 ng_rmnode_self(hook->node); 468 } 469 return (0); 470 } 471 472 /************************************************************************ 473 HELPER STUFF 474 ************************************************************************/ 475 476 /* 477 * Set the BPF program associated with a hook 478 */ 479 static int 480 ng_bpf_setprog(hook_p hook, const struct ng_bpf_hookprog *hp0) 481 { 482 const hinfo_p hip = hook->private; 483 struct ng_bpf_hookprog *hp; 484 int size; 485 486 /* Check program for validity */ 487 if (!bpf_validate(hp0->bpf_prog, hp0->bpf_prog_len)) 488 return (EINVAL); 489 490 /* Make a copy of the program */ 491 size = NG_BPF_HOOKPROG_SIZE(hp0->bpf_prog_len); 492 MALLOC(hp, struct ng_bpf_hookprog *, size, M_NETGRAPH, M_NOWAIT); 493 if (hp == NULL) 494 return (ENOMEM); 495 bcopy(hp0, hp, size); 496 497 /* Free previous program, if any, and assign new one */ 498 if (hip->prog != NULL) 499 FREE(hip->prog, M_NETGRAPH); 500 hip->prog = hp; 501 return (0); 502 } 503 504