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