1 /* 2 * Copyright (c) 1993, 1994, 1995, 1996, 1998 3 * The Regents of the University of California. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that: (1) source code distributions 7 * retain the above copyright notice and this paragraph in its entirety, (2) 8 * distributions including binary code include the above copyright notice and 9 * this paragraph in its entirety in the documentation or other materials 10 * provided with the distribution, and (3) all advertising materials mentioning 11 * features or use of this software display the following acknowledgement: 12 * ``This product includes software developed by the University of California, 13 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of 14 * the University nor the names of its contributors may be used to endorse 15 * or promote products derived from this software without specific prior 16 * written permission. 17 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED 18 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF 19 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 20 */ 21 #ifndef lint 22 static const char rcsid[] _U_ = 23 "@(#) $Header: /tcpdump/master/libpcap/pcap-bpf.c,v 1.86.2.12 2007/06/15 17:57:27 guy Exp $ (LBL)"; 24 #endif 25 26 #ifdef HAVE_CONFIG_H 27 #include "config.h" 28 #endif 29 30 #include <sys/param.h> /* optionally get BSD define */ 31 #include <sys/time.h> 32 #include <sys/timeb.h> 33 #include <sys/socket.h> 34 #include <sys/file.h> 35 #include <sys/ioctl.h> 36 #include <sys/utsname.h> 37 38 #include <net/if.h> 39 40 #ifdef _AIX 41 42 /* 43 * Make "pcap.h" not include "pcap-bpf.h"; we are going to include the 44 * native OS version, as we need "struct bpf_config" from it. 45 */ 46 #define PCAP_DONT_INCLUDE_PCAP_BPF_H 47 48 #include <sys/types.h> 49 50 /* 51 * Prevent bpf.h from redefining the DLT_ values to their 52 * IFT_ values, as we're going to return the standard libpcap 53 * values, not IBM's non-standard IFT_ values. 54 */ 55 #undef _AIX 56 #include <net/bpf.h> 57 #define _AIX 58 59 #include <net/if_types.h> /* for IFT_ values */ 60 #include <sys/sysconfig.h> 61 #include <sys/device.h> 62 #include <sys/cfgodm.h> 63 #include <cf.h> 64 65 #ifdef __64BIT__ 66 #define domakedev makedev64 67 #define getmajor major64 68 #define bpf_hdr bpf_hdr32 69 #else /* __64BIT__ */ 70 #define domakedev makedev 71 #define getmajor major 72 #endif /* __64BIT__ */ 73 74 #define BPF_NAME "bpf" 75 #define BPF_MINORS 4 76 #define DRIVER_PATH "/usr/lib/drivers" 77 #define BPF_NODE "/dev/bpf" 78 static int bpfloadedflag = 0; 79 static int odmlockid = 0; 80 81 #else /* _AIX */ 82 83 #include <net/bpf.h> 84 85 #endif /* _AIX */ 86 87 #include <ctype.h> 88 #include <errno.h> 89 #include <netdb.h> 90 #include <stdio.h> 91 #include <stdlib.h> 92 #include <string.h> 93 #include <unistd.h> 94 95 #include "pcap-int.h" 96 97 #ifdef HAVE_DAG_API 98 #include "pcap-dag.h" 99 #endif /* HAVE_DAG_API */ 100 101 #ifdef HAVE_OS_PROTO_H 102 #include "os-proto.h" 103 #endif 104 105 #include "gencode.h" /* for "no_optimize" */ 106 107 static int pcap_setfilter_bpf(pcap_t *p, struct bpf_program *fp); 108 static int pcap_setdirection_bpf(pcap_t *, pcap_direction_t); 109 static int pcap_set_datalink_bpf(pcap_t *p, int dlt); 110 111 static int 112 pcap_stats_bpf(pcap_t *p, struct pcap_stat *ps) 113 { 114 struct bpf_stat s; 115 116 /* 117 * "ps_recv" counts packets handed to the filter, not packets 118 * that passed the filter. This includes packets later dropped 119 * because we ran out of buffer space. 120 * 121 * "ps_drop" counts packets dropped inside the BPF device 122 * because we ran out of buffer space. It doesn't count 123 * packets dropped by the interface driver. It counts 124 * only packets that passed the filter. 125 * 126 * Both statistics include packets not yet read from the kernel 127 * by libpcap, and thus not yet seen by the application. 128 */ 129 if (ioctl(p->fd, BIOCGSTATS, (caddr_t)&s) < 0) { 130 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCGSTATS: %s", 131 pcap_strerror(errno)); 132 return (-1); 133 } 134 135 ps->ps_recv = s.bs_recv; 136 ps->ps_drop = s.bs_drop; 137 return (0); 138 } 139 140 static int 141 pcap_read_bpf(pcap_t *p, int cnt, pcap_handler callback, u_char *user) 142 { 143 int cc; 144 int n = 0; 145 register u_char *bp, *ep; 146 u_char *datap; 147 struct bpf_insn *fcode; 148 #ifdef PCAP_FDDIPAD 149 register int pad; 150 #endif 151 152 fcode = p->md.use_bpf ? NULL : p->fcode.bf_insns; 153 again: 154 /* 155 * Has "pcap_breakloop()" been called? 156 */ 157 if (p->break_loop) { 158 /* 159 * Yes - clear the flag that indicates that it 160 * has, and return -2 to indicate that we were 161 * told to break out of the loop. 162 */ 163 p->break_loop = 0; 164 return (-2); 165 } 166 cc = p->cc; 167 if (p->cc == 0) { 168 cc = read(p->fd, (char *)p->buffer, p->bufsize); 169 if (cc < 0) { 170 /* Don't choke when we get ptraced */ 171 switch (errno) { 172 173 case EINTR: 174 goto again; 175 176 #ifdef _AIX 177 case EFAULT: 178 /* 179 * Sigh. More AIX wonderfulness. 180 * 181 * For some unknown reason the uiomove() 182 * operation in the bpf kernel extension 183 * used to copy the buffer into user 184 * space sometimes returns EFAULT. I have 185 * no idea why this is the case given that 186 * a kernel debugger shows the user buffer 187 * is correct. This problem appears to 188 * be mostly mitigated by the memset of 189 * the buffer before it is first used. 190 * Very strange.... Shaun Clowes 191 * 192 * In any case this means that we shouldn't 193 * treat EFAULT as a fatal error; as we 194 * don't have an API for returning 195 * a "some packets were dropped since 196 * the last packet you saw" indication, 197 * we just ignore EFAULT and keep reading. 198 */ 199 goto again; 200 #endif 201 202 case EWOULDBLOCK: 203 return (0); 204 #if defined(sun) && !defined(BSD) 205 /* 206 * Due to a SunOS bug, after 2^31 bytes, the kernel 207 * file offset overflows and read fails with EINVAL. 208 * The lseek() to 0 will fix things. 209 */ 210 case EINVAL: 211 if (lseek(p->fd, 0L, SEEK_CUR) + 212 p->bufsize < 0) { 213 (void)lseek(p->fd, 0L, SEEK_SET); 214 goto again; 215 } 216 /* fall through */ 217 #endif 218 } 219 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "read: %s", 220 pcap_strerror(errno)); 221 return (-1); 222 } 223 bp = p->buffer; 224 } else 225 bp = p->bp; 226 227 /* 228 * Loop through each packet. 229 */ 230 #define bhp ((struct bpf_hdr *)bp) 231 ep = bp + cc; 232 #ifdef PCAP_FDDIPAD 233 pad = p->fddipad; 234 #endif 235 while (bp < ep) { 236 register int caplen, hdrlen; 237 238 /* 239 * Has "pcap_breakloop()" been called? 240 * If so, return immediately - if we haven't read any 241 * packets, clear the flag and return -2 to indicate 242 * that we were told to break out of the loop, otherwise 243 * leave the flag set, so that the *next* call will break 244 * out of the loop without having read any packets, and 245 * return the number of packets we've processed so far. 246 */ 247 if (p->break_loop) { 248 if (n == 0) { 249 p->break_loop = 0; 250 return (-2); 251 } else { 252 p->bp = bp; 253 p->cc = ep - bp; 254 return (n); 255 } 256 } 257 258 caplen = bhp->bh_caplen; 259 hdrlen = bhp->bh_hdrlen; 260 datap = bp + hdrlen; 261 /* 262 * Short-circuit evaluation: if using BPF filter 263 * in kernel, no need to do it now. 264 * 265 #ifdef PCAP_FDDIPAD 266 * Note: the filter code was generated assuming 267 * that p->fddipad was the amount of padding 268 * before the header, as that's what's required 269 * in the kernel, so we run the filter before 270 * skipping that padding. 271 #endif 272 */ 273 if (fcode == NULL || 274 bpf_filter(fcode, datap, bhp->bh_datalen, caplen)) { 275 struct pcap_pkthdr pkthdr; 276 277 pkthdr.ts.tv_sec = bhp->bh_tstamp.tv_sec; 278 #ifdef _AIX 279 /* 280 * AIX's BPF returns seconds/nanoseconds time 281 * stamps, not seconds/microseconds time stamps. 282 */ 283 pkthdr.ts.tv_usec = bhp->bh_tstamp.tv_usec/1000; 284 #else 285 pkthdr.ts.tv_usec = bhp->bh_tstamp.tv_usec; 286 #endif 287 #ifdef PCAP_FDDIPAD 288 if (caplen > pad) 289 pkthdr.caplen = caplen - pad; 290 else 291 pkthdr.caplen = 0; 292 if (bhp->bh_datalen > pad) 293 pkthdr.len = bhp->bh_datalen - pad; 294 else 295 pkthdr.len = 0; 296 datap += pad; 297 #else 298 pkthdr.caplen = caplen; 299 pkthdr.len = bhp->bh_datalen; 300 #endif 301 (*callback)(user, &pkthdr, datap); 302 bp += BPF_WORDALIGN(caplen + hdrlen); 303 if (++n >= cnt && cnt > 0) { 304 p->bp = bp; 305 p->cc = ep - bp; 306 return (n); 307 } 308 } else { 309 /* 310 * Skip this packet. 311 */ 312 bp += BPF_WORDALIGN(caplen + hdrlen); 313 } 314 } 315 #undef bhp 316 p->cc = 0; 317 return (n); 318 } 319 320 static int 321 pcap_inject_bpf(pcap_t *p, const void *buf, size_t size) 322 { 323 int ret; 324 325 ret = write(p->fd, buf, size); 326 #ifdef __APPLE__ 327 if (ret == -1 && errno == EAFNOSUPPORT) { 328 /* 329 * In Mac OS X, there's a bug wherein setting the 330 * BIOCSHDRCMPLT flag causes writes to fail; see, 331 * for example: 332 * 333 * http://cerberus.sourcefire.com/~jeff/archives/patches/macosx/BIOCSHDRCMPLT-10.3.3.patch 334 * 335 * So, if, on OS X, we get EAFNOSUPPORT from the write, we 336 * assume it's due to that bug, and turn off that flag 337 * and try again. If we succeed, it either means that 338 * somebody applied the fix from that URL, or other patches 339 * for that bug from 340 * 341 * http://cerberus.sourcefire.com/~jeff/archives/patches/macosx/ 342 * 343 * and are running a Darwin kernel with those fixes, or 344 * that Apple fixed the problem in some OS X release. 345 */ 346 u_int spoof_eth_src = 0; 347 348 if (ioctl(p->fd, BIOCSHDRCMPLT, &spoof_eth_src) == -1) { 349 (void)snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 350 "send: can't turn off BIOCSHDRCMPLT: %s", 351 pcap_strerror(errno)); 352 return (-1); 353 } 354 355 /* 356 * Now try the write again. 357 */ 358 ret = write(p->fd, buf, size); 359 } 360 #endif /* __APPLE__ */ 361 if (ret == -1) { 362 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "send: %s", 363 pcap_strerror(errno)); 364 return (-1); 365 } 366 return (ret); 367 } 368 369 #ifdef _AIX 370 static int 371 bpf_odminit(char *errbuf) 372 { 373 char *errstr; 374 375 if (odm_initialize() == -1) { 376 if (odm_err_msg(odmerrno, &errstr) == -1) 377 errstr = "Unknown error"; 378 snprintf(errbuf, PCAP_ERRBUF_SIZE, 379 "bpf_load: odm_initialize failed: %s", 380 errstr); 381 return (-1); 382 } 383 384 if ((odmlockid = odm_lock("/etc/objrepos/config_lock", ODM_WAIT)) == -1) { 385 if (odm_err_msg(odmerrno, &errstr) == -1) 386 errstr = "Unknown error"; 387 snprintf(errbuf, PCAP_ERRBUF_SIZE, 388 "bpf_load: odm_lock of /etc/objrepos/config_lock failed: %s", 389 errstr); 390 return (-1); 391 } 392 393 return (0); 394 } 395 396 static int 397 bpf_odmcleanup(char *errbuf) 398 { 399 char *errstr; 400 401 if (odm_unlock(odmlockid) == -1) { 402 if (odm_err_msg(odmerrno, &errstr) == -1) 403 errstr = "Unknown error"; 404 snprintf(errbuf, PCAP_ERRBUF_SIZE, 405 "bpf_load: odm_unlock failed: %s", 406 errstr); 407 return (-1); 408 } 409 410 if (odm_terminate() == -1) { 411 if (odm_err_msg(odmerrno, &errstr) == -1) 412 errstr = "Unknown error"; 413 snprintf(errbuf, PCAP_ERRBUF_SIZE, 414 "bpf_load: odm_terminate failed: %s", 415 errstr); 416 return (-1); 417 } 418 419 return (0); 420 } 421 422 static int 423 bpf_load(char *errbuf) 424 { 425 long major; 426 int *minors; 427 int numminors, i, rc; 428 char buf[1024]; 429 struct stat sbuf; 430 struct bpf_config cfg_bpf; 431 struct cfg_load cfg_ld; 432 struct cfg_kmod cfg_km; 433 434 /* 435 * This is very very close to what happens in the real implementation 436 * but I've fixed some (unlikely) bug situations. 437 */ 438 if (bpfloadedflag) 439 return (0); 440 441 if (bpf_odminit(errbuf) != 0) 442 return (-1); 443 444 major = genmajor(BPF_NAME); 445 if (major == -1) { 446 snprintf(errbuf, PCAP_ERRBUF_SIZE, 447 "bpf_load: genmajor failed: %s", pcap_strerror(errno)); 448 return (-1); 449 } 450 451 minors = getminor(major, &numminors, BPF_NAME); 452 if (!minors) { 453 minors = genminor("bpf", major, 0, BPF_MINORS, 1, 1); 454 if (!minors) { 455 snprintf(errbuf, PCAP_ERRBUF_SIZE, 456 "bpf_load: genminor failed: %s", 457 pcap_strerror(errno)); 458 return (-1); 459 } 460 } 461 462 if (bpf_odmcleanup(errbuf)) 463 return (-1); 464 465 rc = stat(BPF_NODE "0", &sbuf); 466 if (rc == -1 && errno != ENOENT) { 467 snprintf(errbuf, PCAP_ERRBUF_SIZE, 468 "bpf_load: can't stat %s: %s", 469 BPF_NODE "0", pcap_strerror(errno)); 470 return (-1); 471 } 472 473 if (rc == -1 || getmajor(sbuf.st_rdev) != major) { 474 for (i = 0; i < BPF_MINORS; i++) { 475 sprintf(buf, "%s%d", BPF_NODE, i); 476 unlink(buf); 477 if (mknod(buf, S_IRUSR | S_IFCHR, domakedev(major, i)) == -1) { 478 snprintf(errbuf, PCAP_ERRBUF_SIZE, 479 "bpf_load: can't mknod %s: %s", 480 buf, pcap_strerror(errno)); 481 return (-1); 482 } 483 } 484 } 485 486 /* Check if the driver is loaded */ 487 memset(&cfg_ld, 0x0, sizeof(cfg_ld)); 488 cfg_ld.path = buf; 489 sprintf(cfg_ld.path, "%s/%s", DRIVER_PATH, BPF_NAME); 490 if ((sysconfig(SYS_QUERYLOAD, (void *)&cfg_ld, sizeof(cfg_ld)) == -1) || 491 (cfg_ld.kmid == 0)) { 492 /* Driver isn't loaded, load it now */ 493 if (sysconfig(SYS_SINGLELOAD, (void *)&cfg_ld, sizeof(cfg_ld)) == -1) { 494 snprintf(errbuf, PCAP_ERRBUF_SIZE, 495 "bpf_load: could not load driver: %s", 496 strerror(errno)); 497 return (-1); 498 } 499 } 500 501 /* Configure the driver */ 502 cfg_km.cmd = CFG_INIT; 503 cfg_km.kmid = cfg_ld.kmid; 504 cfg_km.mdilen = sizeof(cfg_bpf); 505 cfg_km.mdiptr = (void *)&cfg_bpf; 506 for (i = 0; i < BPF_MINORS; i++) { 507 cfg_bpf.devno = domakedev(major, i); 508 if (sysconfig(SYS_CFGKMOD, (void *)&cfg_km, sizeof(cfg_km)) == -1) { 509 snprintf(errbuf, PCAP_ERRBUF_SIZE, 510 "bpf_load: could not configure driver: %s", 511 strerror(errno)); 512 return (-1); 513 } 514 } 515 516 bpfloadedflag = 1; 517 518 return (0); 519 } 520 #endif 521 522 static inline int 523 bpf_open(pcap_t *p, char *errbuf) 524 { 525 int fd; 526 #ifdef HAVE_CLONING_BPF 527 static const char device[] = "/dev/bpf"; 528 #else 529 int n = 0; 530 char device[sizeof "/dev/bpf0000000000"]; 531 #endif 532 533 #ifdef _AIX 534 /* 535 * Load the bpf driver, if it isn't already loaded, 536 * and create the BPF device entries, if they don't 537 * already exist. 538 */ 539 if (bpf_load(errbuf) == -1) 540 return (-1); 541 #endif 542 543 #ifdef HAVE_CLONING_BPF 544 if ((fd = open(device, O_RDWR)) == -1 && 545 (errno != EACCES || (fd = open(device, O_RDONLY)) == -1)) 546 snprintf(errbuf, PCAP_ERRBUF_SIZE, 547 "(cannot open device) %s: %s", device, pcap_strerror(errno)); 548 #else 549 /* 550 * Go through all the minors and find one that isn't in use. 551 */ 552 do { 553 (void)snprintf(device, sizeof(device), "/dev/bpf%d", n++); 554 /* 555 * Initially try a read/write open (to allow the inject 556 * method to work). If that fails due to permission 557 * issues, fall back to read-only. This allows a 558 * non-root user to be granted specific access to pcap 559 * capabilities via file permissions. 560 * 561 * XXX - we should have an API that has a flag that 562 * controls whether to open read-only or read-write, 563 * so that denial of permission to send (or inability 564 * to send, if sending packets isn't supported on 565 * the device in question) can be indicated at open 566 * time. 567 */ 568 fd = open(device, O_RDWR); 569 if (fd == -1 && errno == EACCES) 570 fd = open(device, O_RDONLY); 571 } while (fd < 0 && errno == EBUSY); 572 573 /* 574 * XXX better message for all minors used 575 */ 576 if (fd < 0) 577 snprintf(errbuf, PCAP_ERRBUF_SIZE, "(no devices found) %s: %s", 578 device, pcap_strerror(errno)); 579 #endif 580 581 return (fd); 582 } 583 584 /* 585 * We include the OS's <net/bpf.h>, not our "pcap-bpf.h", so we probably 586 * don't get DLT_DOCSIS defined. 587 */ 588 #ifndef DLT_DOCSIS 589 #define DLT_DOCSIS 143 590 #endif 591 592 pcap_t * 593 pcap_open_live(const char *device, int snaplen, int promisc, int to_ms, 594 char *ebuf) 595 { 596 int fd; 597 struct ifreq ifr; 598 struct bpf_version bv; 599 #ifdef BIOCGDLTLIST 600 struct bpf_dltlist bdl; 601 #endif 602 #if defined(BIOCGHDRCMPLT) && defined(BIOCSHDRCMPLT) 603 u_int spoof_eth_src = 1; 604 #endif 605 u_int v; 606 pcap_t *p; 607 struct bpf_insn total_insn; 608 struct bpf_program total_prog; 609 struct utsname osinfo; 610 611 #ifdef HAVE_DAG_API 612 if (strstr(device, "dag")) { 613 return dag_open_live(device, snaplen, promisc, to_ms, ebuf); 614 } 615 #endif /* HAVE_DAG_API */ 616 617 #ifdef BIOCGDLTLIST 618 memset(&bdl, 0, sizeof(bdl)); 619 #endif 620 621 p = (pcap_t *)malloc(sizeof(*p)); 622 if (p == NULL) { 623 snprintf(ebuf, PCAP_ERRBUF_SIZE, "malloc: %s", 624 pcap_strerror(errno)); 625 return (NULL); 626 } 627 memset(p, 0, sizeof(*p)); 628 fd = bpf_open(p, ebuf); 629 if (fd < 0) 630 goto bad; 631 632 p->fd = fd; 633 p->snapshot = snaplen; 634 635 if (ioctl(fd, BIOCVERSION, (caddr_t)&bv) < 0) { 636 snprintf(ebuf, PCAP_ERRBUF_SIZE, "BIOCVERSION: %s", 637 pcap_strerror(errno)); 638 goto bad; 639 } 640 if (bv.bv_major != BPF_MAJOR_VERSION || 641 bv.bv_minor < BPF_MINOR_VERSION) { 642 snprintf(ebuf, PCAP_ERRBUF_SIZE, 643 "kernel bpf filter out of date"); 644 goto bad; 645 } 646 647 /* 648 * Try finding a good size for the buffer; 32768 may be too 649 * big, so keep cutting it in half until we find a size 650 * that works, or run out of sizes to try. If the default 651 * is larger, don't make it smaller. 652 * 653 * XXX - there should be a user-accessible hook to set the 654 * initial buffer size. 655 */ 656 if ((ioctl(fd, BIOCGBLEN, (caddr_t)&v) < 0) || v < 32768) 657 v = 32768; 658 for ( ; v != 0; v >>= 1) { 659 /* Ignore the return value - this is because the call fails 660 * on BPF systems that don't have kernel malloc. And if 661 * the call fails, it's no big deal, we just continue to 662 * use the standard buffer size. 663 */ 664 (void) ioctl(fd, BIOCSBLEN, (caddr_t)&v); 665 666 (void)strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name)); 667 if (ioctl(fd, BIOCSETIF, (caddr_t)&ifr) >= 0) 668 break; /* that size worked; we're done */ 669 670 if (errno != ENOBUFS) { 671 snprintf(ebuf, PCAP_ERRBUF_SIZE, "BIOCSETIF: %s: %s", 672 device, pcap_strerror(errno)); 673 goto bad; 674 } 675 } 676 677 if (v == 0) { 678 snprintf(ebuf, PCAP_ERRBUF_SIZE, 679 "BIOCSBLEN: %s: No buffer size worked", device); 680 goto bad; 681 } 682 683 /* Get the data link layer type. */ 684 if (ioctl(fd, BIOCGDLT, (caddr_t)&v) < 0) { 685 snprintf(ebuf, PCAP_ERRBUF_SIZE, "BIOCGDLT: %s", 686 pcap_strerror(errno)); 687 goto bad; 688 } 689 #ifdef _AIX 690 /* 691 * AIX's BPF returns IFF_ types, not DLT_ types, in BIOCGDLT. 692 */ 693 switch (v) { 694 695 case IFT_ETHER: 696 case IFT_ISO88023: 697 v = DLT_EN10MB; 698 break; 699 700 case IFT_FDDI: 701 v = DLT_FDDI; 702 break; 703 704 case IFT_ISO88025: 705 v = DLT_IEEE802; 706 break; 707 708 case IFT_LOOP: 709 v = DLT_NULL; 710 break; 711 712 default: 713 /* 714 * We don't know what to map this to yet. 715 */ 716 snprintf(ebuf, PCAP_ERRBUF_SIZE, "unknown interface type %u", 717 v); 718 goto bad; 719 } 720 #endif 721 #if _BSDI_VERSION - 0 >= 199510 722 /* The SLIP and PPP link layer header changed in BSD/OS 2.1 */ 723 switch (v) { 724 725 case DLT_SLIP: 726 v = DLT_SLIP_BSDOS; 727 break; 728 729 case DLT_PPP: 730 v = DLT_PPP_BSDOS; 731 break; 732 733 case 11: /*DLT_FR*/ 734 v = DLT_FRELAY; 735 break; 736 737 case 12: /*DLT_C_HDLC*/ 738 v = DLT_CHDLC; 739 break; 740 } 741 #endif 742 #ifdef PCAP_FDDIPAD 743 if (v == DLT_FDDI) 744 p->fddipad = PCAP_FDDIPAD; 745 else 746 p->fddipad = 0; 747 #endif 748 p->linktype = v; 749 750 #ifdef BIOCGDLTLIST 751 /* 752 * We know the default link type -- now determine all the DLTs 753 * this interface supports. If this fails with EINVAL, it's 754 * not fatal; we just don't get to use the feature later. 755 */ 756 if (ioctl(fd, BIOCGDLTLIST, (caddr_t)&bdl) == 0) { 757 u_int i; 758 int is_ethernet; 759 760 bdl.bfl_list = (u_int *) malloc(sizeof(u_int) * (bdl.bfl_len + 1)); 761 if (bdl.bfl_list == NULL) { 762 (void)snprintf(ebuf, PCAP_ERRBUF_SIZE, "malloc: %s", 763 pcap_strerror(errno)); 764 goto bad; 765 } 766 767 if (ioctl(fd, BIOCGDLTLIST, (caddr_t)&bdl) < 0) { 768 (void)snprintf(ebuf, PCAP_ERRBUF_SIZE, 769 "BIOCGDLTLIST: %s", pcap_strerror(errno)); 770 free(bdl.bfl_list); 771 goto bad; 772 } 773 774 /* 775 * OK, for real Ethernet devices, add DLT_DOCSIS to the 776 * list, so that an application can let you choose it, 777 * in case you're capturing DOCSIS traffic that a Cisco 778 * Cable Modem Termination System is putting out onto 779 * an Ethernet (it doesn't put an Ethernet header onto 780 * the wire, it puts raw DOCSIS frames out on the wire 781 * inside the low-level Ethernet framing). 782 * 783 * A "real Ethernet device" is defined here as a device 784 * that has a link-layer type of DLT_EN10MB and that has 785 * no alternate link-layer types; that's done to exclude 786 * 802.11 interfaces (which might or might not be the 787 * right thing to do, but I suspect it is - Ethernet <-> 788 * 802.11 bridges would probably badly mishandle frames 789 * that don't have Ethernet headers). 790 */ 791 if (p->linktype == DLT_EN10MB) { 792 is_ethernet = 1; 793 for (i = 0; i < bdl.bfl_len; i++) { 794 if (bdl.bfl_list[i] != DLT_EN10MB) { 795 is_ethernet = 0; 796 break; 797 } 798 } 799 if (is_ethernet) { 800 /* 801 * We reserved one more slot at the end of 802 * the list. 803 */ 804 bdl.bfl_list[bdl.bfl_len] = DLT_DOCSIS; 805 bdl.bfl_len++; 806 } 807 } 808 p->dlt_count = bdl.bfl_len; 809 p->dlt_list = bdl.bfl_list; 810 } else { 811 if (errno != EINVAL) { 812 (void)snprintf(ebuf, PCAP_ERRBUF_SIZE, 813 "BIOCGDLTLIST: %s", pcap_strerror(errno)); 814 goto bad; 815 } 816 } 817 #endif 818 819 /* 820 * If this is an Ethernet device, and we don't have a DLT_ list, 821 * give it a list with DLT_EN10MB and DLT_DOCSIS. (That'd give 822 * 802.11 interfaces DLT_DOCSIS, which isn't the right thing to 823 * do, but there's not much we can do about that without finding 824 * some other way of determining whether it's an Ethernet or 802.11 825 * device.) 826 */ 827 if (p->linktype == DLT_EN10MB && p->dlt_count == 0) { 828 p->dlt_list = (u_int *) malloc(sizeof(u_int) * 2); 829 /* 830 * If that fails, just leave the list empty. 831 */ 832 if (p->dlt_list != NULL) { 833 p->dlt_list[0] = DLT_EN10MB; 834 p->dlt_list[1] = DLT_DOCSIS; 835 p->dlt_count = 2; 836 } 837 } 838 839 #if defined(BIOCGHDRCMPLT) && defined(BIOCSHDRCMPLT) 840 /* 841 * Do a BIOCSHDRCMPLT, if defined, to turn that flag on, so 842 * the link-layer source address isn't forcibly overwritten. 843 * (Should we ignore errors? Should we do this only if 844 * we're open for writing?) 845 * 846 * XXX - I seem to remember some packet-sending bug in some 847 * BSDs - check CVS log for "bpf.c"? 848 */ 849 if (ioctl(fd, BIOCSHDRCMPLT, &spoof_eth_src) == -1) { 850 (void)snprintf(ebuf, PCAP_ERRBUF_SIZE, 851 "BIOCSHDRCMPLT: %s", pcap_strerror(errno)); 852 goto bad; 853 } 854 #endif 855 /* set timeout */ 856 if (to_ms != 0) { 857 /* 858 * XXX - is this seconds/nanoseconds in AIX? 859 * (Treating it as such doesn't fix the timeout 860 * problem described below.) 861 */ 862 struct timeval to; 863 to.tv_sec = to_ms / 1000; 864 to.tv_usec = (to_ms * 1000) % 1000000; 865 if (ioctl(p->fd, BIOCSRTIMEOUT, (caddr_t)&to) < 0) { 866 snprintf(ebuf, PCAP_ERRBUF_SIZE, "BIOCSRTIMEOUT: %s", 867 pcap_strerror(errno)); 868 goto bad; 869 } 870 } 871 872 #ifdef _AIX 873 #ifdef BIOCIMMEDIATE 874 /* 875 * Darren Reed notes that 876 * 877 * On AIX (4.2 at least), if BIOCIMMEDIATE is not set, the 878 * timeout appears to be ignored and it waits until the buffer 879 * is filled before returning. The result of not having it 880 * set is almost worse than useless if your BPF filter 881 * is reducing things to only a few packets (i.e. one every 882 * second or so). 883 * 884 * so we turn BIOCIMMEDIATE mode on if this is AIX. 885 * 886 * We don't turn it on for other platforms, as that means we 887 * get woken up for every packet, which may not be what we want; 888 * in the Winter 1993 USENIX paper on BPF, they say: 889 * 890 * Since a process might want to look at every packet on a 891 * network and the time between packets can be only a few 892 * microseconds, it is not possible to do a read system call 893 * per packet and BPF must collect the data from several 894 * packets and return it as a unit when the monitoring 895 * application does a read. 896 * 897 * which I infer is the reason for the timeout - it means we 898 * wait that amount of time, in the hopes that more packets 899 * will arrive and we'll get them all with one read. 900 * 901 * Setting BIOCIMMEDIATE mode on FreeBSD (and probably other 902 * BSDs) causes the timeout to be ignored. 903 * 904 * On the other hand, some platforms (e.g., Linux) don't support 905 * timeouts, they just hand stuff to you as soon as it arrives; 906 * if that doesn't cause a problem on those platforms, it may 907 * be OK to have BIOCIMMEDIATE mode on BSD as well. 908 * 909 * (Note, though, that applications may depend on the read 910 * completing, even if no packets have arrived, when the timeout 911 * expires, e.g. GUI applications that have to check for input 912 * while waiting for packets to arrive; a non-zero timeout 913 * prevents "select()" from working right on FreeBSD and 914 * possibly other BSDs, as the timer doesn't start until a 915 * "read()" is done, so the timer isn't in effect if the 916 * application is blocked on a "select()", and the "select()" 917 * doesn't get woken up for a BPF device until the buffer 918 * fills up.) 919 */ 920 v = 1; 921 if (ioctl(p->fd, BIOCIMMEDIATE, &v) < 0) { 922 snprintf(ebuf, PCAP_ERRBUF_SIZE, "BIOCIMMEDIATE: %s", 923 pcap_strerror(errno)); 924 goto bad; 925 } 926 #endif /* BIOCIMMEDIATE */ 927 #endif /* _AIX */ 928 929 if (promisc) { 930 /* set promiscuous mode, okay if it fails */ 931 if (ioctl(p->fd, BIOCPROMISC, NULL) < 0) { 932 snprintf(ebuf, PCAP_ERRBUF_SIZE, "BIOCPROMISC: %s", 933 pcap_strerror(errno)); 934 } 935 } 936 937 if (ioctl(fd, BIOCGBLEN, (caddr_t)&v) < 0) { 938 snprintf(ebuf, PCAP_ERRBUF_SIZE, "BIOCGBLEN: %s", 939 pcap_strerror(errno)); 940 goto bad; 941 } 942 p->bufsize = v; 943 p->buffer = (u_char *)malloc(p->bufsize); 944 if (p->buffer == NULL) { 945 snprintf(ebuf, PCAP_ERRBUF_SIZE, "malloc: %s", 946 pcap_strerror(errno)); 947 goto bad; 948 } 949 #ifdef _AIX 950 /* For some strange reason this seems to prevent the EFAULT 951 * problems we have experienced from AIX BPF. */ 952 memset(p->buffer, 0x0, p->bufsize); 953 #endif 954 955 /* 956 * If there's no filter program installed, there's 957 * no indication to the kernel of what the snapshot 958 * length should be, so no snapshotting is done. 959 * 960 * Therefore, when we open the device, we install 961 * an "accept everything" filter with the specified 962 * snapshot length. 963 */ 964 total_insn.code = (u_short)(BPF_RET | BPF_K); 965 total_insn.jt = 0; 966 total_insn.jf = 0; 967 total_insn.k = snaplen; 968 969 total_prog.bf_len = 1; 970 total_prog.bf_insns = &total_insn; 971 if (ioctl(p->fd, BIOCSETF, (caddr_t)&total_prog) < 0) { 972 snprintf(ebuf, PCAP_ERRBUF_SIZE, "BIOCSETF: %s", 973 pcap_strerror(errno)); 974 goto bad; 975 } 976 977 /* 978 * On most BPF platforms, either you can do a "select()" or 979 * "poll()" on a BPF file descriptor and it works correctly, 980 * or you can do it and it will return "readable" if the 981 * hold buffer is full but not if the timeout expires *and* 982 * a non-blocking read will, if the hold buffer is empty 983 * but the store buffer isn't empty, rotate the buffers 984 * and return what packets are available. 985 * 986 * In the latter case, the fact that a non-blocking read 987 * will give you the available packets means you can work 988 * around the failure of "select()" and "poll()" to wake up 989 * and return "readable" when the timeout expires by using 990 * the timeout as the "select()" or "poll()" timeout, putting 991 * the BPF descriptor into non-blocking mode, and read from 992 * it regardless of whether "select()" reports it as readable 993 * or not. 994 * 995 * However, in FreeBSD 4.3 and 4.4, "select()" and "poll()" 996 * won't wake up and return "readable" if the timer expires 997 * and non-blocking reads return EWOULDBLOCK if the hold 998 * buffer is empty, even if the store buffer is non-empty. 999 * 1000 * This means the workaround in question won't work. 1001 * 1002 * Therefore, on FreeBSD 4.3 and 4.4, we set "p->selectable_fd" 1003 * to -1, which means "sorry, you can't use 'select()' or 'poll()' 1004 * here". On all other BPF platforms, we set it to the FD for 1005 * the BPF device; in NetBSD, OpenBSD, and Darwin, a non-blocking 1006 * read will, if the hold buffer is empty and the store buffer 1007 * isn't empty, rotate the buffers and return what packets are 1008 * there (and in sufficiently recent versions of OpenBSD 1009 * "select()" and "poll()" should work correctly). 1010 * 1011 * XXX - what about AIX? 1012 */ 1013 p->selectable_fd = p->fd; /* assume select() works until we know otherwise */ 1014 if (uname(&osinfo) == 0) { 1015 /* 1016 * We can check what OS this is. 1017 */ 1018 if (strcmp(osinfo.sysname, "FreeBSD") == 0) { 1019 if (strncmp(osinfo.release, "4.3-", 4) == 0 || 1020 strncmp(osinfo.release, "4.4-", 4) == 0) 1021 p->selectable_fd = -1; 1022 } 1023 } 1024 1025 p->read_op = pcap_read_bpf; 1026 p->inject_op = pcap_inject_bpf; 1027 p->setfilter_op = pcap_setfilter_bpf; 1028 p->setdirection_op = pcap_setdirection_bpf; 1029 p->set_datalink_op = pcap_set_datalink_bpf; 1030 p->getnonblock_op = pcap_getnonblock_fd; 1031 p->setnonblock_op = pcap_setnonblock_fd; 1032 p->stats_op = pcap_stats_bpf; 1033 p->close_op = pcap_close_common; 1034 1035 return (p); 1036 bad: 1037 (void)close(fd); 1038 if (p->dlt_list != NULL) 1039 free(p->dlt_list); 1040 free(p); 1041 return (NULL); 1042 } 1043 1044 int 1045 pcap_platform_finddevs(pcap_if_t **alldevsp, char *errbuf) 1046 { 1047 #ifdef HAVE_DAG_API 1048 if (dag_platform_finddevs(alldevsp, errbuf) < 0) 1049 return (-1); 1050 #endif /* HAVE_DAG_API */ 1051 1052 return (0); 1053 } 1054 1055 static int 1056 pcap_setfilter_bpf(pcap_t *p, struct bpf_program *fp) 1057 { 1058 /* 1059 * It looks that BPF code generated by gen_protochain() is not 1060 * compatible with some of kernel BPF code (for example BSD/OS 3.1). 1061 * Take a safer side for now. 1062 */ 1063 if (no_optimize) { 1064 /* 1065 * XXX - what if we already have a filter in the kernel? 1066 */ 1067 if (install_bpf_program(p, fp) < 0) 1068 return (-1); 1069 p->md.use_bpf = 0; /* filtering in userland */ 1070 return (0); 1071 } 1072 1073 /* 1074 * Free any user-mode filter we might happen to have installed. 1075 */ 1076 pcap_freecode(&p->fcode); 1077 1078 /* 1079 * Try to install the kernel filter. 1080 */ 1081 if (ioctl(p->fd, BIOCSETF, (caddr_t)fp) < 0) { 1082 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCSETF: %s", 1083 pcap_strerror(errno)); 1084 return (-1); 1085 } 1086 p->md.use_bpf = 1; /* filtering in the kernel */ 1087 1088 /* 1089 * Discard any previously-received packets, as they might have 1090 * passed whatever filter was formerly in effect, but might 1091 * not pass this filter (BIOCSETF discards packets buffered 1092 * in the kernel, so you can lose packets in any case). 1093 */ 1094 p->cc = 0; 1095 return (0); 1096 } 1097 1098 /* 1099 * Set direction flag: Which packets do we accept on a forwarding 1100 * single device? IN, OUT or both? 1101 */ 1102 static int 1103 pcap_setdirection_bpf(pcap_t *p, pcap_direction_t d) 1104 { 1105 #if defined(BIOCSDIRECTION) 1106 u_int direction; 1107 1108 direction = (d == PCAP_D_IN) ? BPF_D_IN : 1109 ((d == PCAP_D_OUT) ? BPF_D_OUT : BPF_D_INOUT); 1110 if (ioctl(p->fd, BIOCSDIRECTION, &direction) == -1) { 1111 (void) snprintf(p->errbuf, sizeof(p->errbuf), 1112 "Cannot set direction to %s: %s", 1113 (d == PCAP_D_IN) ? "PCAP_D_IN" : 1114 ((d == PCAP_D_OUT) ? "PCAP_D_OUT" : "PCAP_D_INOUT"), 1115 strerror(errno)); 1116 return (-1); 1117 } 1118 return (0); 1119 #elif defined(BIOCSSEESENT) 1120 u_int seesent; 1121 1122 /* 1123 * We don't support PCAP_D_OUT. 1124 */ 1125 if (d == PCAP_D_OUT) { 1126 snprintf(p->errbuf, sizeof(p->errbuf), 1127 "Setting direction to PCAP_D_OUT is not supported on BPF"); 1128 return -1; 1129 } 1130 1131 seesent = (d == PCAP_D_INOUT); 1132 if (ioctl(p->fd, BIOCSSEESENT, &seesent) == -1) { 1133 (void) snprintf(p->errbuf, sizeof(p->errbuf), 1134 "Cannot set direction to %s: %s", 1135 (d == PCAP_D_INOUT) ? "PCAP_D_INOUT" : "PCAP_D_IN", 1136 strerror(errno)); 1137 return (-1); 1138 } 1139 return (0); 1140 #else 1141 (void) snprintf(p->errbuf, sizeof(p->errbuf), 1142 "This system doesn't support BIOCSSEESENT, so the direction can't be set"); 1143 return (-1); 1144 #endif 1145 } 1146 1147 static int 1148 pcap_set_datalink_bpf(pcap_t *p, int dlt) 1149 { 1150 #ifdef BIOCSDLT 1151 if (ioctl(p->fd, BIOCSDLT, &dlt) == -1) { 1152 (void) snprintf(p->errbuf, sizeof(p->errbuf), 1153 "Cannot set DLT %d: %s", dlt, strerror(errno)); 1154 return (-1); 1155 } 1156 #endif 1157 return (0); 1158 } 1159
