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 * $FreeBSD$ 22 */ 23 #ifndef lint 24 static const char rcsid[] _U_ = 25 "@(#) $Header: /tcpdump/master/libpcap/pcap-bpf.c,v 1.116 2008-09-16 18:42:29 guy Exp $ (LBL)"; 26 #endif 27 28 #ifdef HAVE_CONFIG_H 29 #include "config.h" 30 #endif 31 32 #include <sys/param.h> /* optionally get BSD define */ 33 #ifdef HAVE_ZEROCOPY_BPF 34 #include <sys/mman.h> 35 #endif 36 #include <sys/time.h> 37 #include <sys/socket.h> 38 /* 39 * <net/bpf.h> defines ioctls, but doesn't include <sys/ioccom.h>. 40 * 41 * We include <sys/ioctl.h> as it might be necessary to declare ioctl(); 42 * at least on *BSD and Mac OS X, it also defines various SIOC ioctls - 43 * we could include <sys/sockio.h>, but if we're already including 44 * <sys/ioctl.h>, which includes <sys/sockio.h> on those platforms, 45 * there's not much point in doing so. 46 * 47 * If we have <sys/ioccom.h>, we include it as well, to handle systems 48 * such as Solaris which don't arrange to include <sys/ioccom.h> if you 49 * include <sys/ioctl.h> 50 */ 51 #include <sys/ioctl.h> 52 #ifdef HAVE_SYS_IOCCOM_H 53 #include <sys/ioccom.h> 54 #endif 55 #include <sys/utsname.h> 56 57 #ifdef HAVE_ZEROCOPY_BPF 58 #include <machine/atomic.h> 59 #endif 60 61 #include <net/if.h> 62 63 #ifdef _AIX 64 65 /* 66 * Make "pcap.h" not include "pcap/bpf.h"; we are going to include the 67 * native OS version, as we need "struct bpf_config" from it. 68 */ 69 #define PCAP_DONT_INCLUDE_PCAP_BPF_H 70 71 #include <sys/types.h> 72 73 /* 74 * Prevent bpf.h from redefining the DLT_ values to their 75 * IFT_ values, as we're going to return the standard libpcap 76 * values, not IBM's non-standard IFT_ values. 77 */ 78 #undef _AIX 79 #include <net/bpf.h> 80 #define _AIX 81 82 #include <net/if_types.h> /* for IFT_ values */ 83 #include <sys/sysconfig.h> 84 #include <sys/device.h> 85 #include <sys/cfgodm.h> 86 #include <cf.h> 87 88 #ifdef __64BIT__ 89 #define domakedev makedev64 90 #define getmajor major64 91 #define bpf_hdr bpf_hdr32 92 #else /* __64BIT__ */ 93 #define domakedev makedev 94 #define getmajor major 95 #endif /* __64BIT__ */ 96 97 #define BPF_NAME "bpf" 98 #define BPF_MINORS 4 99 #define DRIVER_PATH "/usr/lib/drivers" 100 #define BPF_NODE "/dev/bpf" 101 static int bpfloadedflag = 0; 102 static int odmlockid = 0; 103 104 static int bpf_load(char *errbuf); 105 106 #else /* _AIX */ 107 108 #include <net/bpf.h> 109 110 #endif /* _AIX */ 111 112 #include <ctype.h> 113 #include <fcntl.h> 114 #include <errno.h> 115 #include <netdb.h> 116 #include <stdio.h> 117 #include <stdlib.h> 118 #include <string.h> 119 #include <unistd.h> 120 121 #ifdef HAVE_NET_IF_MEDIA_H 122 # include <net/if_media.h> 123 #endif 124 125 #include "pcap-int.h" 126 127 #ifdef HAVE_DAG_API 128 #include "pcap-dag.h" 129 #endif /* HAVE_DAG_API */ 130 131 #ifdef HAVE_SNF_API 132 #include "pcap-snf.h" 133 #endif /* HAVE_SNF_API */ 134 135 #ifdef HAVE_OS_PROTO_H 136 #include "os-proto.h" 137 #endif 138 139 #ifdef BIOCGDLTLIST 140 # if (defined(HAVE_NET_IF_MEDIA_H) && defined(IFM_IEEE80211)) && !defined(__APPLE__) 141 #define HAVE_BSD_IEEE80211 142 # endif 143 144 # if defined(__APPLE__) || defined(HAVE_BSD_IEEE80211) 145 static int find_802_11(struct bpf_dltlist *); 146 147 # ifdef HAVE_BSD_IEEE80211 148 static int monitor_mode(pcap_t *, int); 149 # endif 150 151 # if defined(__APPLE__) 152 static void remove_en(pcap_t *); 153 static void remove_802_11(pcap_t *); 154 # endif 155 156 # endif /* defined(__APPLE__) || defined(HAVE_BSD_IEEE80211) */ 157 158 #endif /* BIOCGDLTLIST */ 159 160 /* 161 * We include the OS's <net/bpf.h>, not our "pcap/bpf.h", so we probably 162 * don't get DLT_DOCSIS defined. 163 */ 164 #ifndef DLT_DOCSIS 165 #define DLT_DOCSIS 143 166 #endif 167 168 /* 169 * On OS X, we don't even get any of the 802.11-plus-radio-header DLT_'s 170 * defined, even though some of them are used by various Airport drivers. 171 */ 172 #ifndef DLT_PRISM_HEADER 173 #define DLT_PRISM_HEADER 119 174 #endif 175 #ifndef DLT_AIRONET_HEADER 176 #define DLT_AIRONET_HEADER 120 177 #endif 178 #ifndef DLT_IEEE802_11_RADIO 179 #define DLT_IEEE802_11_RADIO 127 180 #endif 181 #ifndef DLT_IEEE802_11_RADIO_AVS 182 #define DLT_IEEE802_11_RADIO_AVS 163 183 #endif 184 185 static int pcap_can_set_rfmon_bpf(pcap_t *p); 186 static int pcap_activate_bpf(pcap_t *p); 187 static int pcap_setfilter_bpf(pcap_t *p, struct bpf_program *fp); 188 static int pcap_setdirection_bpf(pcap_t *, pcap_direction_t); 189 static int pcap_set_datalink_bpf(pcap_t *p, int dlt); 190 191 #ifdef HAVE_ZEROCOPY_BPF 192 /* 193 * For zerocopy bpf, we need to override the setnonblock/getnonblock routines 194 * so we don't call select(2) if the pcap handle is in non-blocking mode. We 195 * preserve the timeout supplied by pcap_open functions to make sure it 196 * does not get clobbered if the pcap handle moves between blocking and non- 197 * blocking mode. 198 */ 199 static int 200 pcap_getnonblock_zbuf(pcap_t *p, char *errbuf) 201 { 202 /* 203 * Use a negative value for the timeout to represent that the 204 * pcap handle is in non-blocking mode. 205 */ 206 return (p->md.timeout < 0); 207 } 208 209 static int 210 pcap_setnonblock_zbuf(pcap_t *p, int nonblock, char *errbuf) 211 { 212 /* 213 * Map each value to the corresponding 2's complement, to 214 * preserve the timeout value provided with pcap_set_timeout. 215 * (from pcap-linux.c). 216 */ 217 if (nonblock) { 218 if (p->md.timeout >= 0) { 219 /* 220 * Timeout is non-negative, so we're not already 221 * in non-blocking mode; set it to the 2's 222 * complement, to make it negative, as an 223 * indication that we're in non-blocking mode. 224 */ 225 p->md.timeout = p->md.timeout * -1 - 1; 226 } 227 } else { 228 if (p->md.timeout < 0) { 229 /* 230 * Timeout is negative, so we're not already 231 * in blocking mode; reverse the previous 232 * operation, to make the timeout non-negative 233 * again. 234 */ 235 p->md.timeout = (p->md.timeout + 1) * -1; 236 } 237 } 238 return (0); 239 } 240 241 /* 242 * Zero-copy specific close method. Un-map the shared buffers then call 243 * pcap_cleanup_live_common. 244 */ 245 static void 246 pcap_cleanup_zbuf(pcap_t *p) 247 { 248 /* 249 * Delete the mappings. Note that p->buffer gets initialized to one 250 * of the mmapped regions in this case, so do not try and free it 251 * directly; null it out so that pcap_cleanup_live_common() doesn't 252 * try to free it. 253 */ 254 if (p->md.zbuf1 != MAP_FAILED && p->md.zbuf1 != NULL) 255 (void) munmap(p->md.zbuf1, p->md.zbufsize); 256 if (p->md.zbuf2 != MAP_FAILED && p->md.zbuf2 != NULL) 257 (void) munmap(p->md.zbuf2, p->md.zbufsize); 258 p->buffer = NULL; 259 pcap_cleanup_live_common(p); 260 } 261 262 /* 263 * Zero-copy BPF buffer routines to check for and acknowledge BPF data in 264 * shared memory buffers. 265 * 266 * pcap_next_zbuf_shm(): Check for a newly available shared memory buffer, 267 * and set up p->buffer and cc to reflect one if available. Notice that if 268 * there was no prior buffer, we select zbuf1 as this will be the first 269 * buffer filled for a fresh BPF session. 270 */ 271 static int 272 pcap_next_zbuf_shm(pcap_t *p, int *cc) 273 { 274 struct bpf_zbuf_header *bzh; 275 276 if (p->md.zbuffer == p->md.zbuf2 || p->md.zbuffer == NULL) { 277 bzh = (struct bpf_zbuf_header *)p->md.zbuf1; 278 if (bzh->bzh_user_gen != 279 atomic_load_acq_int(&bzh->bzh_kernel_gen)) { 280 p->md.bzh = bzh; 281 p->md.zbuffer = (u_char *)p->md.zbuf1; 282 p->buffer = p->md.zbuffer + sizeof(*bzh); 283 *cc = bzh->bzh_kernel_len; 284 return (1); 285 } 286 } else if (p->md.zbuffer == p->md.zbuf1) { 287 bzh = (struct bpf_zbuf_header *)p->md.zbuf2; 288 if (bzh->bzh_user_gen != 289 atomic_load_acq_int(&bzh->bzh_kernel_gen)) { 290 p->md.bzh = bzh; 291 p->md.zbuffer = (u_char *)p->md.zbuf2; 292 p->buffer = p->md.zbuffer + sizeof(*bzh); 293 *cc = bzh->bzh_kernel_len; 294 return (1); 295 } 296 } 297 *cc = 0; 298 return (0); 299 } 300 301 /* 302 * pcap_next_zbuf() -- Similar to pcap_next_zbuf_shm(), except wait using 303 * select() for data or a timeout, and possibly force rotation of the buffer 304 * in the event we time out or are in immediate mode. Invoke the shared 305 * memory check before doing system calls in order to avoid doing avoidable 306 * work. 307 */ 308 static int 309 pcap_next_zbuf(pcap_t *p, int *cc) 310 { 311 struct bpf_zbuf bz; 312 struct timeval tv; 313 struct timespec cur; 314 fd_set r_set; 315 int data, r; 316 int expire, tmout; 317 318 #define TSTOMILLI(ts) (((ts)->tv_sec * 1000) + ((ts)->tv_nsec / 1000000)) 319 /* 320 * Start out by seeing whether anything is waiting by checking the 321 * next shared memory buffer for data. 322 */ 323 data = pcap_next_zbuf_shm(p, cc); 324 if (data) 325 return (data); 326 /* 327 * If a previous sleep was interrupted due to signal delivery, make 328 * sure that the timeout gets adjusted accordingly. This requires 329 * that we analyze when the timeout should be been expired, and 330 * subtract the current time from that. If after this operation, 331 * our timeout is less then or equal to zero, handle it like a 332 * regular timeout. 333 */ 334 tmout = p->md.timeout; 335 if (tmout) 336 (void) clock_gettime(CLOCK_MONOTONIC, &cur); 337 if (p->md.interrupted && p->md.timeout) { 338 expire = TSTOMILLI(&p->md.firstsel) + p->md.timeout; 339 tmout = expire - TSTOMILLI(&cur); 340 #undef TSTOMILLI 341 if (tmout <= 0) { 342 p->md.interrupted = 0; 343 data = pcap_next_zbuf_shm(p, cc); 344 if (data) 345 return (data); 346 if (ioctl(p->fd, BIOCROTZBUF, &bz) < 0) { 347 (void) snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 348 "BIOCROTZBUF: %s", strerror(errno)); 349 return (PCAP_ERROR); 350 } 351 return (pcap_next_zbuf_shm(p, cc)); 352 } 353 } 354 /* 355 * No data in the buffer, so must use select() to wait for data or 356 * the next timeout. Note that we only call select if the handle 357 * is in blocking mode. 358 */ 359 if (p->md.timeout >= 0) { 360 FD_ZERO(&r_set); 361 FD_SET(p->fd, &r_set); 362 if (tmout != 0) { 363 tv.tv_sec = tmout / 1000; 364 tv.tv_usec = (tmout * 1000) % 1000000; 365 } 366 r = select(p->fd + 1, &r_set, NULL, NULL, 367 p->md.timeout != 0 ? &tv : NULL); 368 if (r < 0 && errno == EINTR) { 369 if (!p->md.interrupted && p->md.timeout) { 370 p->md.interrupted = 1; 371 p->md.firstsel = cur; 372 } 373 return (0); 374 } else if (r < 0) { 375 (void) snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 376 "select: %s", strerror(errno)); 377 return (PCAP_ERROR); 378 } 379 } 380 p->md.interrupted = 0; 381 /* 382 * Check again for data, which may exist now that we've either been 383 * woken up as a result of data or timed out. Try the "there's data" 384 * case first since it doesn't require a system call. 385 */ 386 data = pcap_next_zbuf_shm(p, cc); 387 if (data) 388 return (data); 389 /* 390 * Try forcing a buffer rotation to dislodge timed out or immediate 391 * data. 392 */ 393 if (ioctl(p->fd, BIOCROTZBUF, &bz) < 0) { 394 (void) snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 395 "BIOCROTZBUF: %s", strerror(errno)); 396 return (PCAP_ERROR); 397 } 398 return (pcap_next_zbuf_shm(p, cc)); 399 } 400 401 /* 402 * Notify kernel that we are done with the buffer. We don't reset zbuffer so 403 * that we know which buffer to use next time around. 404 */ 405 static int 406 pcap_ack_zbuf(pcap_t *p) 407 { 408 409 atomic_store_rel_int(&p->md.bzh->bzh_user_gen, 410 p->md.bzh->bzh_kernel_gen); 411 p->md.bzh = NULL; 412 p->buffer = NULL; 413 return (0); 414 } 415 #endif 416 417 pcap_t * 418 pcap_create(const char *device, char *ebuf) 419 { 420 pcap_t *p; 421 422 #ifdef HAVE_DAG_API 423 if (strstr(device, "dag")) 424 return (dag_create(device, ebuf)); 425 #endif /* HAVE_DAG_API */ 426 #ifdef HAVE_SNF_API 427 if (strstr(device, "snf")) 428 return (snf_create(device, ebuf)); 429 #endif /* HAVE_SNF_API */ 430 431 p = pcap_create_common(device, ebuf); 432 if (p == NULL) 433 return (NULL); 434 435 p->activate_op = pcap_activate_bpf; 436 p->can_set_rfmon_op = pcap_can_set_rfmon_bpf; 437 return (p); 438 } 439 440 static int 441 bpf_open(pcap_t *p) 442 { 443 int fd; 444 #ifdef HAVE_CLONING_BPF 445 static const char device[] = "/dev/bpf"; 446 #else 447 int n = 0; 448 char device[sizeof "/dev/bpf0000000000"]; 449 #endif 450 451 #ifdef _AIX 452 /* 453 * Load the bpf driver, if it isn't already loaded, 454 * and create the BPF device entries, if they don't 455 * already exist. 456 */ 457 if (bpf_load(p->errbuf) == PCAP_ERROR) 458 return (PCAP_ERROR); 459 #endif 460 461 #ifdef HAVE_CLONING_BPF 462 if ((fd = open(device, O_RDWR)) == -1 && 463 (errno != EACCES || (fd = open(device, O_RDONLY)) == -1)) { 464 if (errno == EACCES) 465 fd = PCAP_ERROR_PERM_DENIED; 466 else 467 fd = PCAP_ERROR; 468 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 469 "(cannot open device) %s: %s", device, pcap_strerror(errno)); 470 } 471 #else 472 /* 473 * Go through all the minors and find one that isn't in use. 474 */ 475 do { 476 (void)snprintf(device, sizeof(device), "/dev/bpf%d", n++); 477 /* 478 * Initially try a read/write open (to allow the inject 479 * method to work). If that fails due to permission 480 * issues, fall back to read-only. This allows a 481 * non-root user to be granted specific access to pcap 482 * capabilities via file permissions. 483 * 484 * XXX - we should have an API that has a flag that 485 * controls whether to open read-only or read-write, 486 * so that denial of permission to send (or inability 487 * to send, if sending packets isn't supported on 488 * the device in question) can be indicated at open 489 * time. 490 */ 491 fd = open(device, O_RDWR); 492 if (fd == -1 && errno == EACCES) 493 fd = open(device, O_RDONLY); 494 } while (fd < 0 && errno == EBUSY); 495 496 /* 497 * XXX better message for all minors used 498 */ 499 if (fd < 0) { 500 if (errno == EACCES) 501 fd = PCAP_ERROR_PERM_DENIED; 502 else 503 fd = PCAP_ERROR; 504 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "(no devices found) %s: %s", 505 device, pcap_strerror(errno)); 506 } 507 #endif 508 509 return (fd); 510 } 511 512 #ifdef BIOCGDLTLIST 513 static int 514 get_dlt_list(int fd, int v, struct bpf_dltlist *bdlp, char *ebuf) 515 { 516 memset(bdlp, 0, sizeof(*bdlp)); 517 if (ioctl(fd, BIOCGDLTLIST, (caddr_t)bdlp) == 0) { 518 u_int i; 519 int is_ethernet; 520 521 bdlp->bfl_list = (u_int *) malloc(sizeof(u_int) * (bdlp->bfl_len + 1)); 522 if (bdlp->bfl_list == NULL) { 523 (void)snprintf(ebuf, PCAP_ERRBUF_SIZE, "malloc: %s", 524 pcap_strerror(errno)); 525 return (PCAP_ERROR); 526 } 527 528 if (ioctl(fd, BIOCGDLTLIST, (caddr_t)bdlp) < 0) { 529 (void)snprintf(ebuf, PCAP_ERRBUF_SIZE, 530 "BIOCGDLTLIST: %s", pcap_strerror(errno)); 531 free(bdlp->bfl_list); 532 return (PCAP_ERROR); 533 } 534 535 /* 536 * OK, for real Ethernet devices, add DLT_DOCSIS to the 537 * list, so that an application can let you choose it, 538 * in case you're capturing DOCSIS traffic that a Cisco 539 * Cable Modem Termination System is putting out onto 540 * an Ethernet (it doesn't put an Ethernet header onto 541 * the wire, it puts raw DOCSIS frames out on the wire 542 * inside the low-level Ethernet framing). 543 * 544 * A "real Ethernet device" is defined here as a device 545 * that has a link-layer type of DLT_EN10MB and that has 546 * no alternate link-layer types; that's done to exclude 547 * 802.11 interfaces (which might or might not be the 548 * right thing to do, but I suspect it is - Ethernet <-> 549 * 802.11 bridges would probably badly mishandle frames 550 * that don't have Ethernet headers). 551 * 552 * On Solaris with BPF, Ethernet devices also offer 553 * DLT_IPNET, so we, if DLT_IPNET is defined, we don't 554 * treat it as an indication that the device isn't an 555 * Ethernet. 556 */ 557 if (v == DLT_EN10MB) { 558 is_ethernet = 1; 559 for (i = 0; i < bdlp->bfl_len; i++) { 560 if (bdlp->bfl_list[i] != DLT_EN10MB 561 #ifdef DLT_IPNET 562 && bdlp->bfl_list[i] != DLT_IPNET 563 #endif 564 ) { 565 is_ethernet = 0; 566 break; 567 } 568 } 569 if (is_ethernet) { 570 /* 571 * We reserved one more slot at the end of 572 * the list. 573 */ 574 bdlp->bfl_list[bdlp->bfl_len] = DLT_DOCSIS; 575 bdlp->bfl_len++; 576 } 577 } 578 } else { 579 /* 580 * EINVAL just means "we don't support this ioctl on 581 * this device"; don't treat it as an error. 582 */ 583 if (errno != EINVAL) { 584 (void)snprintf(ebuf, PCAP_ERRBUF_SIZE, 585 "BIOCGDLTLIST: %s", pcap_strerror(errno)); 586 return (PCAP_ERROR); 587 } 588 } 589 return (0); 590 } 591 #endif 592 593 static int 594 pcap_can_set_rfmon_bpf(pcap_t *p) 595 { 596 #if defined(__APPLE__) 597 struct utsname osinfo; 598 struct ifreq ifr; 599 int fd; 600 #ifdef BIOCGDLTLIST 601 struct bpf_dltlist bdl; 602 #endif 603 604 /* 605 * The joys of monitor mode on OS X. 606 * 607 * Prior to 10.4, it's not supported at all. 608 * 609 * In 10.4, if adapter enN supports monitor mode, there's a 610 * wltN adapter corresponding to it; you open it, instead of 611 * enN, to get monitor mode. You get whatever link-layer 612 * headers it supplies. 613 * 614 * In 10.5, and, we assume, later releases, if adapter enN 615 * supports monitor mode, it offers, among its selectable 616 * DLT_ values, values that let you get the 802.11 header; 617 * selecting one of those values puts the adapter into monitor 618 * mode (i.e., you can't get 802.11 headers except in monitor 619 * mode, and you can't get Ethernet headers in monitor mode). 620 */ 621 if (uname(&osinfo) == -1) { 622 /* 623 * Can't get the OS version; just say "no". 624 */ 625 return (0); 626 } 627 /* 628 * We assume osinfo.sysname is "Darwin", because 629 * __APPLE__ is defined. We just check the version. 630 */ 631 if (osinfo.release[0] < '8' && osinfo.release[1] == '.') { 632 /* 633 * 10.3 (Darwin 7.x) or earlier. 634 * Monitor mode not supported. 635 */ 636 return (0); 637 } 638 if (osinfo.release[0] == '8' && osinfo.release[1] == '.') { 639 /* 640 * 10.4 (Darwin 8.x). s/en/wlt/, and check 641 * whether the device exists. 642 */ 643 if (strncmp(p->opt.source, "en", 2) != 0) { 644 /* 645 * Not an enN device; no monitor mode. 646 */ 647 return (0); 648 } 649 fd = socket(AF_INET, SOCK_DGRAM, 0); 650 if (fd == -1) { 651 (void)snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 652 "socket: %s", pcap_strerror(errno)); 653 return (PCAP_ERROR); 654 } 655 strlcpy(ifr.ifr_name, "wlt", sizeof(ifr.ifr_name)); 656 strlcat(ifr.ifr_name, p->opt.source + 2, sizeof(ifr.ifr_name)); 657 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifr) < 0) { 658 /* 659 * No such device? 660 */ 661 close(fd); 662 return (0); 663 } 664 close(fd); 665 return (1); 666 } 667 668 #ifdef BIOCGDLTLIST 669 /* 670 * Everything else is 10.5 or later; for those, 671 * we just open the enN device, and check whether 672 * we have any 802.11 devices. 673 * 674 * First, open a BPF device. 675 */ 676 fd = bpf_open(p); 677 if (fd < 0) 678 return (fd); 679 680 /* 681 * Now bind to the device. 682 */ 683 (void)strncpy(ifr.ifr_name, p->opt.source, sizeof(ifr.ifr_name)); 684 if (ioctl(fd, BIOCSETIF, (caddr_t)&ifr) < 0) { 685 if (errno == ENETDOWN) { 686 /* 687 * Return a "network down" indication, so that 688 * the application can report that rather than 689 * saying we had a mysterious failure and 690 * suggest that they report a problem to the 691 * libpcap developers. 692 */ 693 close(fd); 694 return (PCAP_ERROR_IFACE_NOT_UP); 695 } else { 696 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 697 "BIOCSETIF: %s: %s", 698 p->opt.source, pcap_strerror(errno)); 699 close(fd); 700 return (PCAP_ERROR); 701 } 702 } 703 704 /* 705 * We know the default link type -- now determine all the DLTs 706 * this interface supports. If this fails with EINVAL, it's 707 * not fatal; we just don't get to use the feature later. 708 * (We don't care about DLT_DOCSIS, so we pass DLT_NULL 709 * as the default DLT for this adapter.) 710 */ 711 if (get_dlt_list(fd, DLT_NULL, &bdl, p->errbuf) == PCAP_ERROR) { 712 close(fd); 713 return (PCAP_ERROR); 714 } 715 if (find_802_11(&bdl) != -1) { 716 /* 717 * We have an 802.11 DLT, so we can set monitor mode. 718 */ 719 free(bdl.bfl_list); 720 close(fd); 721 return (1); 722 } 723 free(bdl.bfl_list); 724 #endif /* BIOCGDLTLIST */ 725 return (0); 726 #elif defined(HAVE_BSD_IEEE80211) 727 int ret; 728 729 ret = monitor_mode(p, 0); 730 if (ret == PCAP_ERROR_RFMON_NOTSUP) 731 return (0); /* not an error, just a "can't do" */ 732 if (ret == 0) 733 return (1); /* success */ 734 return (ret); 735 #else 736 return (0); 737 #endif 738 } 739 740 static int 741 pcap_stats_bpf(pcap_t *p, struct pcap_stat *ps) 742 { 743 struct bpf_stat s; 744 745 /* 746 * "ps_recv" counts packets handed to the filter, not packets 747 * that passed the filter. This includes packets later dropped 748 * because we ran out of buffer space. 749 * 750 * "ps_drop" counts packets dropped inside the BPF device 751 * because we ran out of buffer space. It doesn't count 752 * packets dropped by the interface driver. It counts 753 * only packets that passed the filter. 754 * 755 * Both statistics include packets not yet read from the kernel 756 * by libpcap, and thus not yet seen by the application. 757 */ 758 if (ioctl(p->fd, BIOCGSTATS, (caddr_t)&s) < 0) { 759 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCGSTATS: %s", 760 pcap_strerror(errno)); 761 return (PCAP_ERROR); 762 } 763 764 ps->ps_recv = s.bs_recv; 765 ps->ps_drop = s.bs_drop; 766 ps->ps_ifdrop = 0; 767 return (0); 768 } 769 770 static int 771 pcap_read_bpf(pcap_t *p, int cnt, pcap_handler callback, u_char *user) 772 { 773 int cc; 774 int n = 0; 775 register u_char *bp, *ep; 776 u_char *datap; 777 #ifdef PCAP_FDDIPAD 778 register int pad; 779 #endif 780 #ifdef HAVE_ZEROCOPY_BPF 781 int i; 782 #endif 783 784 again: 785 /* 786 * Has "pcap_breakloop()" been called? 787 */ 788 if (p->break_loop) { 789 /* 790 * Yes - clear the flag that indicates that it 791 * has, and return PCAP_ERROR_BREAK to indicate 792 * that we were told to break out of the loop. 793 */ 794 p->break_loop = 0; 795 return (PCAP_ERROR_BREAK); 796 } 797 cc = p->cc; 798 if (p->cc == 0) { 799 /* 800 * When reading without zero-copy from a file descriptor, we 801 * use a single buffer and return a length of data in the 802 * buffer. With zero-copy, we update the p->buffer pointer 803 * to point at whatever underlying buffer contains the next 804 * data and update cc to reflect the data found in the 805 * buffer. 806 */ 807 #ifdef HAVE_ZEROCOPY_BPF 808 if (p->md.zerocopy) { 809 if (p->buffer != NULL) 810 pcap_ack_zbuf(p); 811 i = pcap_next_zbuf(p, &cc); 812 if (i == 0) 813 goto again; 814 if (i < 0) 815 return (PCAP_ERROR); 816 } else 817 #endif 818 { 819 cc = read(p->fd, (char *)p->buffer, p->bufsize); 820 } 821 if (cc < 0) { 822 /* Don't choke when we get ptraced */ 823 switch (errno) { 824 825 case EINTR: 826 goto again; 827 828 #ifdef _AIX 829 case EFAULT: 830 /* 831 * Sigh. More AIX wonderfulness. 832 * 833 * For some unknown reason the uiomove() 834 * operation in the bpf kernel extension 835 * used to copy the buffer into user 836 * space sometimes returns EFAULT. I have 837 * no idea why this is the case given that 838 * a kernel debugger shows the user buffer 839 * is correct. This problem appears to 840 * be mostly mitigated by the memset of 841 * the buffer before it is first used. 842 * Very strange.... Shaun Clowes 843 * 844 * In any case this means that we shouldn't 845 * treat EFAULT as a fatal error; as we 846 * don't have an API for returning 847 * a "some packets were dropped since 848 * the last packet you saw" indication, 849 * we just ignore EFAULT and keep reading. 850 */ 851 goto again; 852 #endif 853 854 case EWOULDBLOCK: 855 return (0); 856 857 case ENXIO: 858 /* 859 * The device on which we're capturing 860 * went away. 861 * 862 * XXX - we should really return 863 * PCAP_ERROR_IFACE_NOT_UP, but 864 * pcap_dispatch() etc. aren't 865 * defined to retur that. 866 */ 867 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 868 "The interface went down"); 869 return (PCAP_ERROR); 870 871 #if defined(sun) && !defined(BSD) && !defined(__svr4__) && !defined(__SVR4) 872 /* 873 * Due to a SunOS bug, after 2^31 bytes, the kernel 874 * file offset overflows and read fails with EINVAL. 875 * The lseek() to 0 will fix things. 876 */ 877 case EINVAL: 878 if (lseek(p->fd, 0L, SEEK_CUR) + 879 p->bufsize < 0) { 880 (void)lseek(p->fd, 0L, SEEK_SET); 881 goto again; 882 } 883 /* fall through */ 884 #endif 885 } 886 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "read: %s", 887 pcap_strerror(errno)); 888 return (PCAP_ERROR); 889 } 890 bp = p->buffer; 891 } else 892 bp = p->bp; 893 894 /* 895 * Loop through each packet. 896 */ 897 #define bhp ((struct bpf_hdr *)bp) 898 ep = bp + cc; 899 #ifdef PCAP_FDDIPAD 900 pad = p->fddipad; 901 #endif 902 while (bp < ep) { 903 register int caplen, hdrlen; 904 905 /* 906 * Has "pcap_breakloop()" been called? 907 * If so, return immediately - if we haven't read any 908 * packets, clear the flag and return PCAP_ERROR_BREAK 909 * to indicate that we were told to break out of the loop, 910 * otherwise leave the flag set, so that the *next* call 911 * will break out of the loop without having read any 912 * packets, and return the number of packets we've 913 * processed so far. 914 */ 915 if (p->break_loop) { 916 if (n == 0) { 917 p->break_loop = 0; 918 return (PCAP_ERROR_BREAK); 919 } else { 920 p->bp = bp; 921 p->cc = ep - bp; 922 return (n); 923 } 924 } 925 926 caplen = bhp->bh_caplen; 927 hdrlen = bhp->bh_hdrlen; 928 datap = bp + hdrlen; 929 /* 930 * Short-circuit evaluation: if using BPF filter 931 * in kernel, no need to do it now - we already know 932 * the packet passed the filter. 933 * 934 #ifdef PCAP_FDDIPAD 935 * Note: the filter code was generated assuming 936 * that p->fddipad was the amount of padding 937 * before the header, as that's what's required 938 * in the kernel, so we run the filter before 939 * skipping that padding. 940 #endif 941 */ 942 if (p->md.use_bpf || 943 bpf_filter(p->fcode.bf_insns, datap, bhp->bh_datalen, caplen)) { 944 struct pcap_pkthdr pkthdr; 945 946 pkthdr.ts.tv_sec = bhp->bh_tstamp.tv_sec; 947 #ifdef _AIX 948 /* 949 * AIX's BPF returns seconds/nanoseconds time 950 * stamps, not seconds/microseconds time stamps. 951 */ 952 pkthdr.ts.tv_usec = bhp->bh_tstamp.tv_usec/1000; 953 #else 954 pkthdr.ts.tv_usec = bhp->bh_tstamp.tv_usec; 955 #endif 956 #ifdef PCAP_FDDIPAD 957 if (caplen > pad) 958 pkthdr.caplen = caplen - pad; 959 else 960 pkthdr.caplen = 0; 961 if (bhp->bh_datalen > pad) 962 pkthdr.len = bhp->bh_datalen - pad; 963 else 964 pkthdr.len = 0; 965 datap += pad; 966 #else 967 pkthdr.caplen = caplen; 968 pkthdr.len = bhp->bh_datalen; 969 #endif 970 (*callback)(user, &pkthdr, datap); 971 bp += BPF_WORDALIGN(caplen + hdrlen); 972 if (++n >= cnt && cnt > 0) { 973 p->bp = bp; 974 p->cc = ep - bp; 975 return (n); 976 } 977 } else { 978 /* 979 * Skip this packet. 980 */ 981 bp += BPF_WORDALIGN(caplen + hdrlen); 982 } 983 } 984 #undef bhp 985 p->cc = 0; 986 return (n); 987 } 988 989 static int 990 pcap_inject_bpf(pcap_t *p, const void *buf, size_t size) 991 { 992 int ret; 993 994 ret = write(p->fd, buf, size); 995 #ifdef __APPLE__ 996 if (ret == -1 && errno == EAFNOSUPPORT) { 997 /* 998 * In Mac OS X, there's a bug wherein setting the 999 * BIOCSHDRCMPLT flag causes writes to fail; see, 1000 * for example: 1001 * 1002 * http://cerberus.sourcefire.com/~jeff/archives/patches/macosx/BIOCSHDRCMPLT-10.3.3.patch 1003 * 1004 * So, if, on OS X, we get EAFNOSUPPORT from the write, we 1005 * assume it's due to that bug, and turn off that flag 1006 * and try again. If we succeed, it either means that 1007 * somebody applied the fix from that URL, or other patches 1008 * for that bug from 1009 * 1010 * http://cerberus.sourcefire.com/~jeff/archives/patches/macosx/ 1011 * 1012 * and are running a Darwin kernel with those fixes, or 1013 * that Apple fixed the problem in some OS X release. 1014 */ 1015 u_int spoof_eth_src = 0; 1016 1017 if (ioctl(p->fd, BIOCSHDRCMPLT, &spoof_eth_src) == -1) { 1018 (void)snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 1019 "send: can't turn off BIOCSHDRCMPLT: %s", 1020 pcap_strerror(errno)); 1021 return (PCAP_ERROR); 1022 } 1023 1024 /* 1025 * Now try the write again. 1026 */ 1027 ret = write(p->fd, buf, size); 1028 } 1029 #endif /* __APPLE__ */ 1030 if (ret == -1) { 1031 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "send: %s", 1032 pcap_strerror(errno)); 1033 return (PCAP_ERROR); 1034 } 1035 return (ret); 1036 } 1037 1038 #ifdef _AIX 1039 static int 1040 bpf_odminit(char *errbuf) 1041 { 1042 char *errstr; 1043 1044 if (odm_initialize() == -1) { 1045 if (odm_err_msg(odmerrno, &errstr) == -1) 1046 errstr = "Unknown error"; 1047 snprintf(errbuf, PCAP_ERRBUF_SIZE, 1048 "bpf_load: odm_initialize failed: %s", 1049 errstr); 1050 return (PCAP_ERROR); 1051 } 1052 1053 if ((odmlockid = odm_lock("/etc/objrepos/config_lock", ODM_WAIT)) == -1) { 1054 if (odm_err_msg(odmerrno, &errstr) == -1) 1055 errstr = "Unknown error"; 1056 snprintf(errbuf, PCAP_ERRBUF_SIZE, 1057 "bpf_load: odm_lock of /etc/objrepos/config_lock failed: %s", 1058 errstr); 1059 (void)odm_terminate(); 1060 return (PCAP_ERROR); 1061 } 1062 1063 return (0); 1064 } 1065 1066 static int 1067 bpf_odmcleanup(char *errbuf) 1068 { 1069 char *errstr; 1070 1071 if (odm_unlock(odmlockid) == -1) { 1072 if (errbuf != NULL) { 1073 if (odm_err_msg(odmerrno, &errstr) == -1) 1074 errstr = "Unknown error"; 1075 snprintf(errbuf, PCAP_ERRBUF_SIZE, 1076 "bpf_load: odm_unlock failed: %s", 1077 errstr); 1078 } 1079 return (PCAP_ERROR); 1080 } 1081 1082 if (odm_terminate() == -1) { 1083 if (errbuf != NULL) { 1084 if (odm_err_msg(odmerrno, &errstr) == -1) 1085 errstr = "Unknown error"; 1086 snprintf(errbuf, PCAP_ERRBUF_SIZE, 1087 "bpf_load: odm_terminate failed: %s", 1088 errstr); 1089 } 1090 return (PCAP_ERROR); 1091 } 1092 1093 return (0); 1094 } 1095 1096 static int 1097 bpf_load(char *errbuf) 1098 { 1099 long major; 1100 int *minors; 1101 int numminors, i, rc; 1102 char buf[1024]; 1103 struct stat sbuf; 1104 struct bpf_config cfg_bpf; 1105 struct cfg_load cfg_ld; 1106 struct cfg_kmod cfg_km; 1107 1108 /* 1109 * This is very very close to what happens in the real implementation 1110 * but I've fixed some (unlikely) bug situations. 1111 */ 1112 if (bpfloadedflag) 1113 return (0); 1114 1115 if (bpf_odminit(errbuf) == PCAP_ERROR) 1116 return (PCAP_ERROR); 1117 1118 major = genmajor(BPF_NAME); 1119 if (major == -1) { 1120 snprintf(errbuf, PCAP_ERRBUF_SIZE, 1121 "bpf_load: genmajor failed: %s", pcap_strerror(errno)); 1122 (void)bpf_odmcleanup(NULL); 1123 return (PCAP_ERROR); 1124 } 1125 1126 minors = getminor(major, &numminors, BPF_NAME); 1127 if (!minors) { 1128 minors = genminor("bpf", major, 0, BPF_MINORS, 1, 1); 1129 if (!minors) { 1130 snprintf(errbuf, PCAP_ERRBUF_SIZE, 1131 "bpf_load: genminor failed: %s", 1132 pcap_strerror(errno)); 1133 (void)bpf_odmcleanup(NULL); 1134 return (PCAP_ERROR); 1135 } 1136 } 1137 1138 if (bpf_odmcleanup(errbuf) == PCAP_ERROR) 1139 return (PCAP_ERROR); 1140 1141 rc = stat(BPF_NODE "0", &sbuf); 1142 if (rc == -1 && errno != ENOENT) { 1143 snprintf(errbuf, PCAP_ERRBUF_SIZE, 1144 "bpf_load: can't stat %s: %s", 1145 BPF_NODE "0", pcap_strerror(errno)); 1146 return (PCAP_ERROR); 1147 } 1148 1149 if (rc == -1 || getmajor(sbuf.st_rdev) != major) { 1150 for (i = 0; i < BPF_MINORS; i++) { 1151 sprintf(buf, "%s%d", BPF_NODE, i); 1152 unlink(buf); 1153 if (mknod(buf, S_IRUSR | S_IFCHR, domakedev(major, i)) == -1) { 1154 snprintf(errbuf, PCAP_ERRBUF_SIZE, 1155 "bpf_load: can't mknod %s: %s", 1156 buf, pcap_strerror(errno)); 1157 return (PCAP_ERROR); 1158 } 1159 } 1160 } 1161 1162 /* Check if the driver is loaded */ 1163 memset(&cfg_ld, 0x0, sizeof(cfg_ld)); 1164 cfg_ld.path = buf; 1165 sprintf(cfg_ld.path, "%s/%s", DRIVER_PATH, BPF_NAME); 1166 if ((sysconfig(SYS_QUERYLOAD, (void *)&cfg_ld, sizeof(cfg_ld)) == -1) || 1167 (cfg_ld.kmid == 0)) { 1168 /* Driver isn't loaded, load it now */ 1169 if (sysconfig(SYS_SINGLELOAD, (void *)&cfg_ld, sizeof(cfg_ld)) == -1) { 1170 snprintf(errbuf, PCAP_ERRBUF_SIZE, 1171 "bpf_load: could not load driver: %s", 1172 strerror(errno)); 1173 return (PCAP_ERROR); 1174 } 1175 } 1176 1177 /* Configure the driver */ 1178 cfg_km.cmd = CFG_INIT; 1179 cfg_km.kmid = cfg_ld.kmid; 1180 cfg_km.mdilen = sizeof(cfg_bpf); 1181 cfg_km.mdiptr = (void *)&cfg_bpf; 1182 for (i = 0; i < BPF_MINORS; i++) { 1183 cfg_bpf.devno = domakedev(major, i); 1184 if (sysconfig(SYS_CFGKMOD, (void *)&cfg_km, sizeof(cfg_km)) == -1) { 1185 snprintf(errbuf, PCAP_ERRBUF_SIZE, 1186 "bpf_load: could not configure driver: %s", 1187 strerror(errno)); 1188 return (PCAP_ERROR); 1189 } 1190 } 1191 1192 bpfloadedflag = 1; 1193 1194 return (0); 1195 } 1196 #endif 1197 1198 /* 1199 * Turn off rfmon mode if necessary. 1200 */ 1201 static void 1202 pcap_cleanup_bpf(pcap_t *p) 1203 { 1204 #ifdef HAVE_BSD_IEEE80211 1205 int sock; 1206 struct ifmediareq req; 1207 struct ifreq ifr; 1208 #endif 1209 1210 if (p->md.must_do_on_close != 0) { 1211 /* 1212 * There's something we have to do when closing this 1213 * pcap_t. 1214 */ 1215 #ifdef HAVE_BSD_IEEE80211 1216 if (p->md.must_do_on_close & MUST_CLEAR_RFMON) { 1217 /* 1218 * We put the interface into rfmon mode; 1219 * take it out of rfmon mode. 1220 * 1221 * XXX - if somebody else wants it in rfmon 1222 * mode, this code cannot know that, so it'll take 1223 * it out of rfmon mode. 1224 */ 1225 sock = socket(AF_INET, SOCK_DGRAM, 0); 1226 if (sock == -1) { 1227 fprintf(stderr, 1228 "Can't restore interface flags (socket() failed: %s).\n" 1229 "Please adjust manually.\n", 1230 strerror(errno)); 1231 } else { 1232 memset(&req, 0, sizeof(req)); 1233 strncpy(req.ifm_name, p->md.device, 1234 sizeof(req.ifm_name)); 1235 if (ioctl(sock, SIOCGIFMEDIA, &req) < 0) { 1236 fprintf(stderr, 1237 "Can't restore interface flags (SIOCGIFMEDIA failed: %s).\n" 1238 "Please adjust manually.\n", 1239 strerror(errno)); 1240 } else { 1241 if (req.ifm_current & IFM_IEEE80211_MONITOR) { 1242 /* 1243 * Rfmon mode is currently on; 1244 * turn it off. 1245 */ 1246 memset(&ifr, 0, sizeof(ifr)); 1247 (void)strncpy(ifr.ifr_name, 1248 p->md.device, 1249 sizeof(ifr.ifr_name)); 1250 ifr.ifr_media = 1251 req.ifm_current & ~IFM_IEEE80211_MONITOR; 1252 if (ioctl(sock, SIOCSIFMEDIA, 1253 &ifr) == -1) { 1254 fprintf(stderr, 1255 "Can't restore interface flags (SIOCSIFMEDIA failed: %s).\n" 1256 "Please adjust manually.\n", 1257 strerror(errno)); 1258 } 1259 } 1260 } 1261 close(sock); 1262 } 1263 } 1264 #endif /* HAVE_BSD_IEEE80211 */ 1265 1266 /* 1267 * Take this pcap out of the list of pcaps for which we 1268 * have to take the interface out of some mode. 1269 */ 1270 pcap_remove_from_pcaps_to_close(p); 1271 p->md.must_do_on_close = 0; 1272 } 1273 1274 #ifdef HAVE_ZEROCOPY_BPF 1275 /* 1276 * In zero-copy mode, p->buffer is just a pointer into one of the two 1277 * memory-mapped buffers, so no need to free it. 1278 */ 1279 if (p->md.zerocopy) { 1280 if (p->md.zbuf1 != MAP_FAILED && p->md.zbuf1 != NULL) 1281 munmap(p->md.zbuf1, p->md.zbufsize); 1282 if (p->md.zbuf2 != MAP_FAILED && p->md.zbuf2 != NULL) 1283 munmap(p->md.zbuf2, p->md.zbufsize); 1284 p->buffer = NULL; 1285 } 1286 #endif 1287 if (p->md.device != NULL) { 1288 free(p->md.device); 1289 p->md.device = NULL; 1290 } 1291 pcap_cleanup_live_common(p); 1292 } 1293 1294 static int 1295 check_setif_failure(pcap_t *p, int error) 1296 { 1297 #ifdef __APPLE__ 1298 int fd; 1299 struct ifreq ifr; 1300 int err; 1301 #endif 1302 1303 if (error == ENXIO) { 1304 /* 1305 * No such device exists. 1306 */ 1307 #ifdef __APPLE__ 1308 if (p->opt.rfmon && strncmp(p->opt.source, "wlt", 3) == 0) { 1309 /* 1310 * Monitor mode was requested, and we're trying 1311 * to open a "wltN" device. Assume that this 1312 * is 10.4 and that we were asked to open an 1313 * "enN" device; if that device exists, return 1314 * "monitor mode not supported on the device". 1315 */ 1316 fd = socket(AF_INET, SOCK_DGRAM, 0); 1317 if (fd != -1) { 1318 strlcpy(ifr.ifr_name, "en", 1319 sizeof(ifr.ifr_name)); 1320 strlcat(ifr.ifr_name, p->opt.source + 3, 1321 sizeof(ifr.ifr_name)); 1322 if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifr) < 0) { 1323 /* 1324 * We assume this failed because 1325 * the underlying device doesn't 1326 * exist. 1327 */ 1328 err = PCAP_ERROR_NO_SUCH_DEVICE; 1329 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 1330 "SIOCGIFFLAGS on %s failed: %s", 1331 ifr.ifr_name, pcap_strerror(errno)); 1332 } else { 1333 /* 1334 * The underlying "enN" device 1335 * exists, but there's no 1336 * corresponding "wltN" device; 1337 * that means that the "enN" 1338 * device doesn't support 1339 * monitor mode, probably because 1340 * it's an Ethernet device rather 1341 * than a wireless device. 1342 */ 1343 err = PCAP_ERROR_RFMON_NOTSUP; 1344 } 1345 close(fd); 1346 } else { 1347 /* 1348 * We can't find out whether there's 1349 * an underlying "enN" device, so 1350 * just report "no such device". 1351 */ 1352 err = PCAP_ERROR_NO_SUCH_DEVICE; 1353 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 1354 "socket() failed: %s", 1355 pcap_strerror(errno)); 1356 } 1357 return (err); 1358 } 1359 #endif 1360 /* 1361 * No such device. 1362 */ 1363 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCSETIF failed: %s", 1364 pcap_strerror(errno)); 1365 return (PCAP_ERROR_NO_SUCH_DEVICE); 1366 } else if (errno == ENETDOWN) { 1367 /* 1368 * Return a "network down" indication, so that 1369 * the application can report that rather than 1370 * saying we had a mysterious failure and 1371 * suggest that they report a problem to the 1372 * libpcap developers. 1373 */ 1374 return (PCAP_ERROR_IFACE_NOT_UP); 1375 } else { 1376 /* 1377 * Some other error; fill in the error string, and 1378 * return PCAP_ERROR. 1379 */ 1380 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCSETIF: %s: %s", 1381 p->opt.source, pcap_strerror(errno)); 1382 return (PCAP_ERROR); 1383 } 1384 } 1385 1386 /* 1387 * Default capture buffer size. 1388 * 32K isn't very much for modern machines with fast networks; we 1389 * pick .5M, as that's the maximum on at least some systems with BPF. 1390 */ 1391 #define DEFAULT_BUFSIZE 524288 1392 1393 static int 1394 pcap_activate_bpf(pcap_t *p) 1395 { 1396 int status = 0; 1397 int fd; 1398 struct ifreq ifr; 1399 struct bpf_version bv; 1400 #ifdef __APPLE__ 1401 int sockfd; 1402 char *wltdev = NULL; 1403 #endif 1404 #ifdef BIOCGDLTLIST 1405 struct bpf_dltlist bdl; 1406 #if defined(__APPLE__) || defined(HAVE_BSD_IEEE80211) 1407 int new_dlt; 1408 #endif 1409 #endif /* BIOCGDLTLIST */ 1410 #if defined(BIOCGHDRCMPLT) && defined(BIOCSHDRCMPLT) 1411 u_int spoof_eth_src = 1; 1412 #endif 1413 u_int v; 1414 struct bpf_insn total_insn; 1415 struct bpf_program total_prog; 1416 struct utsname osinfo; 1417 1418 #ifdef HAVE_DAG_API 1419 if (strstr(device, "dag")) { 1420 return dag_open_live(device, snaplen, promisc, to_ms, ebuf); 1421 } 1422 #endif /* HAVE_DAG_API */ 1423 1424 #ifdef BIOCGDLTLIST 1425 memset(&bdl, 0, sizeof(bdl)); 1426 int have_osinfo = 0; 1427 #ifdef HAVE_ZEROCOPY_BPF 1428 struct bpf_zbuf bz; 1429 u_int bufmode, zbufmax; 1430 #endif 1431 1432 fd = bpf_open(p); 1433 if (fd < 0) { 1434 status = fd; 1435 goto bad; 1436 } 1437 1438 p->fd = fd; 1439 1440 if (ioctl(fd, BIOCVERSION, (caddr_t)&bv) < 0) { 1441 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCVERSION: %s", 1442 pcap_strerror(errno)); 1443 status = PCAP_ERROR; 1444 goto bad; 1445 } 1446 if (bv.bv_major != BPF_MAJOR_VERSION || 1447 bv.bv_minor < BPF_MINOR_VERSION) { 1448 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 1449 "kernel bpf filter out of date"); 1450 status = PCAP_ERROR; 1451 goto bad; 1452 } 1453 1454 p->md.device = strdup(p->opt.source); 1455 if (p->md.device == NULL) { 1456 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "strdup: %s", 1457 pcap_strerror(errno)); 1458 status = PCAP_ERROR; 1459 goto bad; 1460 } 1461 1462 /* 1463 * Try finding a good size for the buffer; 32768 may be too 1464 * big, so keep cutting it in half until we find a size 1465 * that works, or run out of sizes to try. If the default 1466 * is larger, don't make it smaller. 1467 * 1468 * XXX - there should be a user-accessible hook to set the 1469 * initial buffer size. 1470 * Attempt to find out the version of the OS on which we're running. 1471 */ 1472 if (uname(&osinfo) == 0) 1473 have_osinfo = 1; 1474 1475 #ifdef __APPLE__ 1476 /* 1477 * See comment in pcap_can_set_rfmon_bpf() for an explanation 1478 * of why we check the version number. 1479 */ 1480 if (p->opt.rfmon) { 1481 if (have_osinfo) { 1482 /* 1483 * We assume osinfo.sysname is "Darwin", because 1484 * __APPLE__ is defined. We just check the version. 1485 */ 1486 if (osinfo.release[0] < '8' && 1487 osinfo.release[1] == '.') { 1488 /* 1489 * 10.3 (Darwin 7.x) or earlier. 1490 */ 1491 status = PCAP_ERROR_RFMON_NOTSUP; 1492 goto bad; 1493 } 1494 if (osinfo.release[0] == '8' && 1495 osinfo.release[1] == '.') { 1496 /* 1497 * 10.4 (Darwin 8.x). s/en/wlt/ 1498 */ 1499 if (strncmp(p->opt.source, "en", 2) != 0) { 1500 /* 1501 * Not an enN device; check 1502 * whether the device even exists. 1503 */ 1504 sockfd = socket(AF_INET, SOCK_DGRAM, 0); 1505 if (sockfd != -1) { 1506 strlcpy(ifr.ifr_name, 1507 p->opt.source, 1508 sizeof(ifr.ifr_name)); 1509 if (ioctl(sockfd, SIOCGIFFLAGS, 1510 (char *)&ifr) < 0) { 1511 /* 1512 * We assume this 1513 * failed because 1514 * the underlying 1515 * device doesn't 1516 * exist. 1517 */ 1518 status = PCAP_ERROR_NO_SUCH_DEVICE; 1519 snprintf(p->errbuf, 1520 PCAP_ERRBUF_SIZE, 1521 "SIOCGIFFLAGS failed: %s", 1522 pcap_strerror(errno)); 1523 } else 1524 status = PCAP_ERROR_RFMON_NOTSUP; 1525 close(sockfd); 1526 } else { 1527 /* 1528 * We can't find out whether 1529 * the device exists, so just 1530 * report "no such device". 1531 */ 1532 status = PCAP_ERROR_NO_SUCH_DEVICE; 1533 snprintf(p->errbuf, 1534 PCAP_ERRBUF_SIZE, 1535 "socket() failed: %s", 1536 pcap_strerror(errno)); 1537 } 1538 goto bad; 1539 } 1540 wltdev = malloc(strlen(p->opt.source) + 2); 1541 if (wltdev == NULL) { 1542 (void)snprintf(p->errbuf, 1543 PCAP_ERRBUF_SIZE, "malloc: %s", 1544 pcap_strerror(errno)); 1545 status = PCAP_ERROR; 1546 goto bad; 1547 } 1548 strcpy(wltdev, "wlt"); 1549 strcat(wltdev, p->opt.source + 2); 1550 free(p->opt.source); 1551 p->opt.source = wltdev; 1552 } 1553 /* 1554 * Everything else is 10.5 or later; for those, 1555 * we just open the enN device, and set the DLT. 1556 */ 1557 } 1558 } 1559 #endif /* __APPLE__ */ 1560 #ifdef HAVE_ZEROCOPY_BPF 1561 /* 1562 * If the BPF extension to set buffer mode is present, try setting 1563 * the mode to zero-copy. If that fails, use regular buffering. If 1564 * it succeeds but other setup fails, return an error to the user. 1565 */ 1566 bufmode = BPF_BUFMODE_ZBUF; 1567 if (ioctl(fd, BIOCSETBUFMODE, (caddr_t)&bufmode) == 0) { 1568 /* 1569 * We have zerocopy BPF; use it. 1570 */ 1571 p->md.zerocopy = 1; 1572 1573 /* 1574 * Set the cleanup and set/get nonblocking mode ops 1575 * as appropriate for zero-copy mode. 1576 */ 1577 p->cleanup_op = pcap_cleanup_zbuf; 1578 p->setnonblock_op = pcap_setnonblock_zbuf; 1579 p->getnonblock_op = pcap_getnonblock_zbuf; 1580 1581 /* 1582 * How to pick a buffer size: first, query the maximum buffer 1583 * size supported by zero-copy. This also lets us quickly 1584 * determine whether the kernel generally supports zero-copy. 1585 * Then, if a buffer size was specified, use that, otherwise 1586 * query the default buffer size, which reflects kernel 1587 * policy for a desired default. Round to the nearest page 1588 * size. 1589 */ 1590 if (ioctl(fd, BIOCGETZMAX, (caddr_t)&zbufmax) < 0) { 1591 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCGETZMAX: %s", 1592 pcap_strerror(errno)); 1593 goto bad; 1594 } 1595 1596 if (p->opt.buffer_size != 0) { 1597 /* 1598 * A buffer size was explicitly specified; use it. 1599 */ 1600 v = p->opt.buffer_size; 1601 } else { 1602 if ((ioctl(fd, BIOCGBLEN, (caddr_t)&v) < 0) || 1603 v < DEFAULT_BUFSIZE) 1604 v = DEFAULT_BUFSIZE; 1605 } 1606 #ifndef roundup 1607 #define roundup(x, y) ((((x)+((y)-1))/(y))*(y)) /* to any y */ 1608 #endif 1609 p->md.zbufsize = roundup(v, getpagesize()); 1610 if (p->md.zbufsize > zbufmax) 1611 p->md.zbufsize = zbufmax; 1612 p->md.zbuf1 = mmap(NULL, p->md.zbufsize, PROT_READ | PROT_WRITE, 1613 MAP_ANON, -1, 0); 1614 p->md.zbuf2 = mmap(NULL, p->md.zbufsize, PROT_READ | PROT_WRITE, 1615 MAP_ANON, -1, 0); 1616 if (p->md.zbuf1 == MAP_FAILED || p->md.zbuf2 == MAP_FAILED) { 1617 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "mmap: %s", 1618 pcap_strerror(errno)); 1619 goto bad; 1620 } 1621 bzero(&bz, sizeof(bz)); 1622 bz.bz_bufa = p->md.zbuf1; 1623 bz.bz_bufb = p->md.zbuf2; 1624 bz.bz_buflen = p->md.zbufsize; 1625 if (ioctl(fd, BIOCSETZBUF, (caddr_t)&bz) < 0) { 1626 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCSETZBUF: %s", 1627 pcap_strerror(errno)); 1628 goto bad; 1629 } 1630 (void)strncpy(ifr.ifr_name, p->opt.source, sizeof(ifr.ifr_name)); 1631 if (ioctl(fd, BIOCSETIF, (caddr_t)&ifr) < 0) { 1632 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCSETIF: %s: %s", 1633 p->opt.source, pcap_strerror(errno)); 1634 goto bad; 1635 } 1636 v = p->md.zbufsize - sizeof(struct bpf_zbuf_header); 1637 } else 1638 #endif 1639 { 1640 /* 1641 * We don't have zerocopy BPF. 1642 * Set the buffer size. 1643 */ 1644 if (p->opt.buffer_size != 0) { 1645 /* 1646 * A buffer size was explicitly specified; use it. 1647 */ 1648 if (ioctl(fd, BIOCSBLEN, 1649 (caddr_t)&p->opt.buffer_size) < 0) { 1650 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 1651 "BIOCSBLEN: %s: %s", p->opt.source, 1652 pcap_strerror(errno)); 1653 status = PCAP_ERROR; 1654 goto bad; 1655 } 1656 1657 /* 1658 * Now bind to the device. 1659 */ 1660 (void)strncpy(ifr.ifr_name, p->opt.source, 1661 sizeof(ifr.ifr_name)); 1662 if (ioctl(fd, BIOCSETIF, (caddr_t)&ifr) < 0) { 1663 status = check_setif_failure(p, errno); 1664 goto bad; 1665 } 1666 } else { 1667 /* 1668 * No buffer size was explicitly specified. 1669 * 1670 * Try finding a good size for the buffer; 1671 * DEFAULT_BUFSIZE may be too big, so keep 1672 * cutting it in half until we find a size 1673 * that works, or run out of sizes to try. 1674 * If the default is larger, don't make it smaller. 1675 */ 1676 if ((ioctl(fd, BIOCGBLEN, (caddr_t)&v) < 0) || 1677 v < DEFAULT_BUFSIZE) 1678 v = DEFAULT_BUFSIZE; 1679 for ( ; v != 0; v >>= 1) { 1680 /* 1681 * Ignore the return value - this is because the 1682 * call fails on BPF systems that don't have 1683 * kernel malloc. And if the call fails, it's 1684 * no big deal, we just continue to use the 1685 * standard buffer size. 1686 */ 1687 (void) ioctl(fd, BIOCSBLEN, (caddr_t)&v); 1688 1689 (void)strncpy(ifr.ifr_name, p->opt.source, 1690 sizeof(ifr.ifr_name)); 1691 if (ioctl(fd, BIOCSETIF, (caddr_t)&ifr) >= 0) 1692 break; /* that size worked; we're done */ 1693 1694 if (errno != ENOBUFS) { 1695 status = check_setif_failure(p, errno); 1696 goto bad; 1697 } 1698 } 1699 1700 if (v == 0) { 1701 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 1702 "BIOCSBLEN: %s: No buffer size worked", 1703 p->opt.source); 1704 status = PCAP_ERROR; 1705 goto bad; 1706 } 1707 } 1708 } 1709 #endif 1710 1711 /* Get the data link layer type. */ 1712 if (ioctl(fd, BIOCGDLT, (caddr_t)&v) < 0) { 1713 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCGDLT: %s", 1714 pcap_strerror(errno)); 1715 status = PCAP_ERROR; 1716 goto bad; 1717 } 1718 1719 #ifdef _AIX 1720 /* 1721 * AIX's BPF returns IFF_ types, not DLT_ types, in BIOCGDLT. 1722 */ 1723 switch (v) { 1724 1725 case IFT_ETHER: 1726 case IFT_ISO88023: 1727 v = DLT_EN10MB; 1728 break; 1729 1730 case IFT_FDDI: 1731 v = DLT_FDDI; 1732 break; 1733 1734 case IFT_ISO88025: 1735 v = DLT_IEEE802; 1736 break; 1737 1738 case IFT_LOOP: 1739 v = DLT_NULL; 1740 break; 1741 1742 default: 1743 /* 1744 * We don't know what to map this to yet. 1745 */ 1746 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "unknown interface type %u", 1747 v); 1748 status = PCAP_ERROR; 1749 goto bad; 1750 } 1751 #endif 1752 #if _BSDI_VERSION - 0 >= 199510 1753 /* The SLIP and PPP link layer header changed in BSD/OS 2.1 */ 1754 switch (v) { 1755 1756 case DLT_SLIP: 1757 v = DLT_SLIP_BSDOS; 1758 break; 1759 1760 case DLT_PPP: 1761 v = DLT_PPP_BSDOS; 1762 break; 1763 1764 case 11: /*DLT_FR*/ 1765 v = DLT_FRELAY; 1766 break; 1767 1768 case 12: /*DLT_C_HDLC*/ 1769 v = DLT_CHDLC; 1770 break; 1771 } 1772 #endif 1773 1774 #ifdef BIOCGDLTLIST 1775 /* 1776 * We know the default link type -- now determine all the DLTs 1777 * this interface supports. If this fails with EINVAL, it's 1778 * not fatal; we just don't get to use the feature later. 1779 */ 1780 if (get_dlt_list(fd, v, &bdl, p->errbuf) == -1) { 1781 status = PCAP_ERROR; 1782 goto bad; 1783 } 1784 p->dlt_count = bdl.bfl_len; 1785 p->dlt_list = bdl.bfl_list; 1786 1787 #ifdef __APPLE__ 1788 /* 1789 * Monitor mode fun, continued. 1790 * 1791 * For 10.5 and, we're assuming, later releases, as noted above, 1792 * 802.1 adapters that support monitor mode offer both DLT_EN10MB, 1793 * DLT_IEEE802_11, and possibly some 802.11-plus-radio-information 1794 * DLT_ value. Choosing one of the 802.11 DLT_ values will turn 1795 * monitor mode on. 1796 * 1797 * Therefore, if the user asked for monitor mode, we filter out 1798 * the DLT_EN10MB value, as you can't get that in monitor mode, 1799 * and, if the user didn't ask for monitor mode, we filter out 1800 * the 802.11 DLT_ values, because selecting those will turn 1801 * monitor mode on. Then, for monitor mode, if an 802.11-plus- 1802 * radio DLT_ value is offered, we try to select that, otherwise 1803 * we try to select DLT_IEEE802_11. 1804 */ 1805 if (have_osinfo) { 1806 if (isdigit((unsigned)osinfo.release[0]) && 1807 (osinfo.release[0] == '9' || 1808 isdigit((unsigned)osinfo.release[1]))) { 1809 /* 1810 * 10.5 (Darwin 9.x), or later. 1811 */ 1812 new_dlt = find_802_11(&bdl); 1813 if (new_dlt != -1) { 1814 /* 1815 * We have at least one 802.11 DLT_ value, 1816 * so this is an 802.11 interface. 1817 * new_dlt is the best of the 802.11 1818 * DLT_ values in the list. 1819 */ 1820 if (p->opt.rfmon) { 1821 /* 1822 * Our caller wants monitor mode. 1823 * Purge DLT_EN10MB from the list 1824 * of link-layer types, as selecting 1825 * it will keep monitor mode off. 1826 */ 1827 remove_en(p); 1828 1829 /* 1830 * If the new mode we want isn't 1831 * the default mode, attempt to 1832 * select the new mode. 1833 */ 1834 if (new_dlt != v) { 1835 if (ioctl(p->fd, BIOCSDLT, 1836 &new_dlt) != -1) { 1837 /* 1838 * We succeeded; 1839 * make this the 1840 * new DLT_ value. 1841 */ 1842 v = new_dlt; 1843 } 1844 } 1845 } else { 1846 /* 1847 * Our caller doesn't want 1848 * monitor mode. Unless this 1849 * is being done by pcap_open_live(), 1850 * purge the 802.11 link-layer types 1851 * from the list, as selecting 1852 * one of them will turn monitor 1853 * mode on. 1854 */ 1855 if (!p->oldstyle) 1856 remove_802_11(p); 1857 } 1858 } else { 1859 if (p->opt.rfmon) { 1860 /* 1861 * The caller requested monitor 1862 * mode, but we have no 802.11 1863 * link-layer types, so they 1864 * can't have it. 1865 */ 1866 status = PCAP_ERROR_RFMON_NOTSUP; 1867 goto bad; 1868 } 1869 } 1870 } 1871 } 1872 #elif defined(HAVE_BSD_IEEE80211) 1873 /* 1874 * *BSD with the new 802.11 ioctls. 1875 * Do we want monitor mode? 1876 */ 1877 if (p->opt.rfmon) { 1878 /* 1879 * Try to put the interface into monitor mode. 1880 */ 1881 status = monitor_mode(p, 1); 1882 if (status != 0) { 1883 /* 1884 * We failed. 1885 */ 1886 goto bad; 1887 } 1888 1889 /* 1890 * We're in monitor mode. 1891 * Try to find the best 802.11 DLT_ value and, if we 1892 * succeed, try to switch to that mode if we're not 1893 * already in that mode. 1894 */ 1895 new_dlt = find_802_11(&bdl); 1896 if (new_dlt != -1) { 1897 /* 1898 * We have at least one 802.11 DLT_ value. 1899 * new_dlt is the best of the 802.11 1900 * DLT_ values in the list. 1901 * 1902 * If the new mode we want isn't the default mode, 1903 * attempt to select the new mode. 1904 */ 1905 if (new_dlt != v) { 1906 if (ioctl(p->fd, BIOCSDLT, &new_dlt) != -1) { 1907 /* 1908 * We succeeded; make this the 1909 * new DLT_ value. 1910 */ 1911 v = new_dlt; 1912 } 1913 } 1914 } 1915 } 1916 #endif /* various platforms */ 1917 #endif /* BIOCGDLTLIST */ 1918 1919 /* 1920 * If this is an Ethernet device, and we don't have a DLT_ list, 1921 * give it a list with DLT_EN10MB and DLT_DOCSIS. (That'd give 1922 * 802.11 interfaces DLT_DOCSIS, which isn't the right thing to 1923 * do, but there's not much we can do about that without finding 1924 * some other way of determining whether it's an Ethernet or 802.11 1925 * device.) 1926 */ 1927 if (v == DLT_EN10MB && p->dlt_count == 0) { 1928 p->dlt_list = (u_int *) malloc(sizeof(u_int) * 2); 1929 /* 1930 * If that fails, just leave the list empty. 1931 */ 1932 if (p->dlt_list != NULL) { 1933 p->dlt_list[0] = DLT_EN10MB; 1934 p->dlt_list[1] = DLT_DOCSIS; 1935 p->dlt_count = 2; 1936 } 1937 } 1938 #ifdef PCAP_FDDIPAD 1939 if (v == DLT_FDDI) 1940 p->fddipad = PCAP_FDDIPAD; 1941 else 1942 p->fddipad = 0; 1943 #endif 1944 p->linktype = v; 1945 1946 #if defined(BIOCGHDRCMPLT) && defined(BIOCSHDRCMPLT) 1947 /* 1948 * Do a BIOCSHDRCMPLT, if defined, to turn that flag on, so 1949 * the link-layer source address isn't forcibly overwritten. 1950 * (Should we ignore errors? Should we do this only if 1951 * we're open for writing?) 1952 * 1953 * XXX - I seem to remember some packet-sending bug in some 1954 * BSDs - check CVS log for "bpf.c"? 1955 */ 1956 if (ioctl(fd, BIOCSHDRCMPLT, &spoof_eth_src) == -1) { 1957 (void)snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 1958 "BIOCSHDRCMPLT: %s", pcap_strerror(errno)); 1959 status = PCAP_ERROR; 1960 goto bad; 1961 } 1962 #endif 1963 /* set timeout */ 1964 #ifdef HAVE_ZEROCOPY_BPF 1965 if (p->md.timeout != 0 && !p->md.zerocopy) { 1966 #else 1967 if (p->md.timeout) { 1968 #endif 1969 /* 1970 * XXX - is this seconds/nanoseconds in AIX? 1971 * (Treating it as such doesn't fix the timeout 1972 * problem described below.) 1973 * 1974 * XXX - Mac OS X 10.6 mishandles BIOCSRTIMEOUT in 1975 * 64-bit userland - it takes, as an argument, a 1976 * "struct BPF_TIMEVAL", which has 32-bit tv_sec 1977 * and tv_usec, rather than a "struct timeval". 1978 * 1979 * If this platform defines "struct BPF_TIMEVAL", 1980 * we check whether the structure size in BIOCSRTIMEOUT 1981 * is that of a "struct timeval" and, if not, we use 1982 * a "struct BPF_TIMEVAL" rather than a "struct timeval". 1983 * (That way, if the bug is fixed in a future release, 1984 * we will still do the right thing.) 1985 */ 1986 struct timeval to; 1987 #ifdef HAVE_STRUCT_BPF_TIMEVAL 1988 struct BPF_TIMEVAL bpf_to; 1989 1990 if (IOCPARM_LEN(BIOCSRTIMEOUT) != sizeof(struct timeval)) { 1991 bpf_to.tv_sec = p->md.timeout / 1000; 1992 bpf_to.tv_usec = (p->md.timeout * 1000) % 1000000; 1993 if (ioctl(p->fd, BIOCSRTIMEOUT, (caddr_t)&bpf_to) < 0) { 1994 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 1995 "BIOCSRTIMEOUT: %s", pcap_strerror(errno)); 1996 status = PCAP_ERROR; 1997 goto bad; 1998 } 1999 } else { 2000 #endif 2001 to.tv_sec = p->md.timeout / 1000; 2002 to.tv_usec = (p->md.timeout * 1000) % 1000000; 2003 if (ioctl(p->fd, BIOCSRTIMEOUT, (caddr_t)&to) < 0) { 2004 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 2005 "BIOCSRTIMEOUT: %s", pcap_strerror(errno)); 2006 status = PCAP_ERROR; 2007 goto bad; 2008 } 2009 #ifdef HAVE_STRUCT_BPF_TIMEVAL 2010 } 2011 #endif 2012 } 2013 2014 #ifdef _AIX 2015 #ifdef BIOCIMMEDIATE 2016 /* 2017 * Darren Reed notes that 2018 * 2019 * On AIX (4.2 at least), if BIOCIMMEDIATE is not set, the 2020 * timeout appears to be ignored and it waits until the buffer 2021 * is filled before returning. The result of not having it 2022 * set is almost worse than useless if your BPF filter 2023 * is reducing things to only a few packets (i.e. one every 2024 * second or so). 2025 * 2026 * so we turn BIOCIMMEDIATE mode on if this is AIX. 2027 * 2028 * We don't turn it on for other platforms, as that means we 2029 * get woken up for every packet, which may not be what we want; 2030 * in the Winter 1993 USENIX paper on BPF, they say: 2031 * 2032 * Since a process might want to look at every packet on a 2033 * network and the time between packets can be only a few 2034 * microseconds, it is not possible to do a read system call 2035 * per packet and BPF must collect the data from several 2036 * packets and return it as a unit when the monitoring 2037 * application does a read. 2038 * 2039 * which I infer is the reason for the timeout - it means we 2040 * wait that amount of time, in the hopes that more packets 2041 * will arrive and we'll get them all with one read. 2042 * 2043 * Setting BIOCIMMEDIATE mode on FreeBSD (and probably other 2044 * BSDs) causes the timeout to be ignored. 2045 * 2046 * On the other hand, some platforms (e.g., Linux) don't support 2047 * timeouts, they just hand stuff to you as soon as it arrives; 2048 * if that doesn't cause a problem on those platforms, it may 2049 * be OK to have BIOCIMMEDIATE mode on BSD as well. 2050 * 2051 * (Note, though, that applications may depend on the read 2052 * completing, even if no packets have arrived, when the timeout 2053 * expires, e.g. GUI applications that have to check for input 2054 * while waiting for packets to arrive; a non-zero timeout 2055 * prevents "select()" from working right on FreeBSD and 2056 * possibly other BSDs, as the timer doesn't start until a 2057 * "read()" is done, so the timer isn't in effect if the 2058 * application is blocked on a "select()", and the "select()" 2059 * doesn't get woken up for a BPF device until the buffer 2060 * fills up.) 2061 */ 2062 v = 1; 2063 if (ioctl(p->fd, BIOCIMMEDIATE, &v) < 0) { 2064 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCIMMEDIATE: %s", 2065 pcap_strerror(errno)); 2066 status = PCAP_ERROR; 2067 goto bad; 2068 } 2069 #endif /* BIOCIMMEDIATE */ 2070 #endif /* _AIX */ 2071 2072 if (p->opt.promisc) { 2073 /* set promiscuous mode, just warn if it fails */ 2074 if (ioctl(p->fd, BIOCPROMISC, NULL) < 0) { 2075 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCPROMISC: %s", 2076 pcap_strerror(errno)); 2077 status = PCAP_WARNING_PROMISC_NOTSUP; 2078 } 2079 } 2080 2081 if (ioctl(fd, BIOCGBLEN, (caddr_t)&v) < 0) { 2082 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCGBLEN: %s", 2083 pcap_strerror(errno)); 2084 status = PCAP_ERROR; 2085 goto bad; 2086 } 2087 p->bufsize = v; 2088 #ifdef HAVE_ZEROCOPY_BPF 2089 if (!p->md.zerocopy) { 2090 #endif 2091 p->buffer = (u_char *)malloc(p->bufsize); 2092 if (p->buffer == NULL) { 2093 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "malloc: %s", 2094 pcap_strerror(errno)); 2095 status = PCAP_ERROR; 2096 goto bad; 2097 } 2098 #ifdef _AIX 2099 /* For some strange reason this seems to prevent the EFAULT 2100 * problems we have experienced from AIX BPF. */ 2101 memset(p->buffer, 0x0, p->bufsize); 2102 #endif 2103 #ifdef HAVE_ZEROCOPY_BPF 2104 } 2105 #endif 2106 2107 /* 2108 * If there's no filter program installed, there's 2109 * no indication to the kernel of what the snapshot 2110 * length should be, so no snapshotting is done. 2111 * 2112 * Therefore, when we open the device, we install 2113 * an "accept everything" filter with the specified 2114 * snapshot length. 2115 */ 2116 total_insn.code = (u_short)(BPF_RET | BPF_K); 2117 total_insn.jt = 0; 2118 total_insn.jf = 0; 2119 total_insn.k = p->snapshot; 2120 2121 total_prog.bf_len = 1; 2122 total_prog.bf_insns = &total_insn; 2123 if (ioctl(p->fd, BIOCSETF, (caddr_t)&total_prog) < 0) { 2124 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCSETF: %s", 2125 pcap_strerror(errno)); 2126 status = PCAP_ERROR; 2127 goto bad; 2128 } 2129 2130 /* 2131 * On most BPF platforms, either you can do a "select()" or 2132 * "poll()" on a BPF file descriptor and it works correctly, 2133 * or you can do it and it will return "readable" if the 2134 * hold buffer is full but not if the timeout expires *and* 2135 * a non-blocking read will, if the hold buffer is empty 2136 * but the store buffer isn't empty, rotate the buffers 2137 * and return what packets are available. 2138 * 2139 * In the latter case, the fact that a non-blocking read 2140 * will give you the available packets means you can work 2141 * around the failure of "select()" and "poll()" to wake up 2142 * and return "readable" when the timeout expires by using 2143 * the timeout as the "select()" or "poll()" timeout, putting 2144 * the BPF descriptor into non-blocking mode, and read from 2145 * it regardless of whether "select()" reports it as readable 2146 * or not. 2147 * 2148 * However, in FreeBSD 4.3 and 4.4, "select()" and "poll()" 2149 * won't wake up and return "readable" if the timer expires 2150 * and non-blocking reads return EWOULDBLOCK if the hold 2151 * buffer is empty, even if the store buffer is non-empty. 2152 * 2153 * This means the workaround in question won't work. 2154 * 2155 * Therefore, on FreeBSD 4.3 and 4.4, we set "p->selectable_fd" 2156 * to -1, which means "sorry, you can't use 'select()' or 'poll()' 2157 * here". On all other BPF platforms, we set it to the FD for 2158 * the BPF device; in NetBSD, OpenBSD, and Darwin, a non-blocking 2159 * read will, if the hold buffer is empty and the store buffer 2160 * isn't empty, rotate the buffers and return what packets are 2161 * there (and in sufficiently recent versions of OpenBSD 2162 * "select()" and "poll()" should work correctly). 2163 * 2164 * XXX - what about AIX? 2165 */ 2166 p->selectable_fd = p->fd; /* assume select() works until we know otherwise */ 2167 if (have_osinfo) { 2168 /* 2169 * We can check what OS this is. 2170 */ 2171 if (strcmp(osinfo.sysname, "FreeBSD") == 0) { 2172 if (strncmp(osinfo.release, "4.3-", 4) == 0 || 2173 strncmp(osinfo.release, "4.4-", 4) == 0) 2174 p->selectable_fd = -1; 2175 } 2176 } 2177 2178 p->read_op = pcap_read_bpf; 2179 p->inject_op = pcap_inject_bpf; 2180 p->setfilter_op = pcap_setfilter_bpf; 2181 p->setdirection_op = pcap_setdirection_bpf; 2182 p->set_datalink_op = pcap_set_datalink_bpf; 2183 p->getnonblock_op = pcap_getnonblock_fd; 2184 p->setnonblock_op = pcap_setnonblock_fd; 2185 p->stats_op = pcap_stats_bpf; 2186 p->cleanup_op = pcap_cleanup_bpf; 2187 2188 return (status); 2189 bad: 2190 pcap_cleanup_bpf(p); 2191 return (status); 2192 } 2193 2194 int 2195 pcap_platform_finddevs(pcap_if_t **alldevsp, char *errbuf) 2196 { 2197 #ifdef HAVE_DAG_API 2198 if (dag_platform_finddevs(alldevsp, errbuf) < 0) 2199 return (-1); 2200 #endif /* HAVE_DAG_API */ 2201 #ifdef HAVE_SNF_API 2202 if (snf_platform_finddevs(alldevsp, errbuf) < 0) 2203 return (-1); 2204 #endif /* HAVE_SNF_API */ 2205 2206 return (0); 2207 } 2208 2209 #ifdef HAVE_BSD_IEEE80211 2210 static int 2211 monitor_mode(pcap_t *p, int set) 2212 { 2213 int sock; 2214 struct ifmediareq req; 2215 int *media_list; 2216 int i; 2217 int can_do; 2218 struct ifreq ifr; 2219 2220 sock = socket(AF_INET, SOCK_DGRAM, 0); 2221 if (sock == -1) { 2222 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "can't open socket: %s", 2223 pcap_strerror(errno)); 2224 return (PCAP_ERROR); 2225 } 2226 2227 memset(&req, 0, sizeof req); 2228 strncpy(req.ifm_name, p->opt.source, sizeof req.ifm_name); 2229 2230 /* 2231 * Find out how many media types we have. 2232 */ 2233 if (ioctl(sock, SIOCGIFMEDIA, &req) < 0) { 2234 /* 2235 * Can't get the media types. 2236 */ 2237 if (errno == EINVAL) { 2238 /* 2239 * Interface doesn't support SIOC{G,S}IFMEDIA. 2240 */ 2241 close(sock); 2242 return (PCAP_ERROR_RFMON_NOTSUP); 2243 } 2244 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "SIOCGIFMEDIA 1: %s", 2245 pcap_strerror(errno)); 2246 close(sock); 2247 return (PCAP_ERROR); 2248 } 2249 if (req.ifm_count == 0) { 2250 /* 2251 * No media types. 2252 */ 2253 close(sock); 2254 return (PCAP_ERROR_RFMON_NOTSUP); 2255 } 2256 2257 /* 2258 * Allocate a buffer to hold all the media types, and 2259 * get the media types. 2260 */ 2261 media_list = malloc(req.ifm_count * sizeof(int)); 2262 if (media_list == NULL) { 2263 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "malloc: %s", 2264 pcap_strerror(errno)); 2265 close(sock); 2266 return (PCAP_ERROR); 2267 } 2268 req.ifm_ulist = media_list; 2269 if (ioctl(sock, SIOCGIFMEDIA, &req) < 0) { 2270 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "SIOCGIFMEDIA: %s", 2271 pcap_strerror(errno)); 2272 free(media_list); 2273 close(sock); 2274 return (PCAP_ERROR); 2275 } 2276 2277 /* 2278 * Look for an 802.11 "automatic" media type. 2279 * We assume that all 802.11 adapters have that media type, 2280 * and that it will carry the monitor mode supported flag. 2281 */ 2282 can_do = 0; 2283 for (i = 0; i < req.ifm_count; i++) { 2284 if (IFM_TYPE(media_list[i]) == IFM_IEEE80211 2285 && IFM_SUBTYPE(media_list[i]) == IFM_AUTO) { 2286 /* OK, does it do monitor mode? */ 2287 if (media_list[i] & IFM_IEEE80211_MONITOR) { 2288 can_do = 1; 2289 break; 2290 } 2291 } 2292 } 2293 free(media_list); 2294 if (!can_do) { 2295 /* 2296 * This adapter doesn't support monitor mode. 2297 */ 2298 close(sock); 2299 return (PCAP_ERROR_RFMON_NOTSUP); 2300 } 2301 2302 if (set) { 2303 /* 2304 * Don't just check whether we can enable monitor mode, 2305 * do so, if it's not already enabled. 2306 */ 2307 if ((req.ifm_current & IFM_IEEE80211_MONITOR) == 0) { 2308 /* 2309 * Monitor mode isn't currently on, so turn it on, 2310 * and remember that we should turn it off when the 2311 * pcap_t is closed. 2312 */ 2313 2314 /* 2315 * If we haven't already done so, arrange to have 2316 * "pcap_close_all()" called when we exit. 2317 */ 2318 if (!pcap_do_addexit(p)) { 2319 /* 2320 * "atexit()" failed; don't put the interface 2321 * in monitor mode, just give up. 2322 */ 2323 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 2324 "atexit failed"); 2325 close(sock); 2326 return (PCAP_ERROR); 2327 } 2328 memset(&ifr, 0, sizeof(ifr)); 2329 (void)strncpy(ifr.ifr_name, p->opt.source, 2330 sizeof(ifr.ifr_name)); 2331 ifr.ifr_media = req.ifm_current | IFM_IEEE80211_MONITOR; 2332 if (ioctl(sock, SIOCSIFMEDIA, &ifr) == -1) { 2333 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, 2334 "SIOCSIFMEDIA: %s", pcap_strerror(errno)); 2335 close(sock); 2336 return (PCAP_ERROR); 2337 } 2338 2339 p->md.must_do_on_close |= MUST_CLEAR_RFMON; 2340 2341 /* 2342 * Add this to the list of pcaps to close when we exit. 2343 */ 2344 pcap_add_to_pcaps_to_close(p); 2345 } 2346 } 2347 return (0); 2348 } 2349 #endif /* HAVE_BSD_IEEE80211 */ 2350 2351 #if defined(BIOCGDLTLIST) && (defined(__APPLE__) || defined(HAVE_BSD_IEEE80211)) 2352 /* 2353 * Check whether we have any 802.11 link-layer types; return the best 2354 * of the 802.11 link-layer types if we find one, and return -1 2355 * otherwise. 2356 * 2357 * DLT_IEEE802_11_RADIO, with the radiotap header, is considered the 2358 * best 802.11 link-layer type; any of the other 802.11-plus-radio 2359 * headers are second-best; 802.11 with no radio information is 2360 * the least good. 2361 */ 2362 static int 2363 find_802_11(struct bpf_dltlist *bdlp) 2364 { 2365 int new_dlt; 2366 int i; 2367 2368 /* 2369 * Scan the list of DLT_ values, looking for 802.11 values, 2370 * and, if we find any, choose the best of them. 2371 */ 2372 new_dlt = -1; 2373 for (i = 0; i < bdlp->bfl_len; i++) { 2374 switch (bdlp->bfl_list[i]) { 2375 2376 case DLT_IEEE802_11: 2377 /* 2378 * 802.11, but no radio. 2379 * 2380 * Offer this, and select it as the new mode 2381 * unless we've already found an 802.11 2382 * header with radio information. 2383 */ 2384 if (new_dlt == -1) 2385 new_dlt = bdlp->bfl_list[i]; 2386 break; 2387 2388 case DLT_PRISM_HEADER: 2389 case DLT_AIRONET_HEADER: 2390 case DLT_IEEE802_11_RADIO_AVS: 2391 /* 2392 * 802.11 with radio, but not radiotap. 2393 * 2394 * Offer this, and select it as the new mode 2395 * unless we've already found the radiotap DLT_. 2396 */ 2397 if (new_dlt != DLT_IEEE802_11_RADIO) 2398 new_dlt = bdlp->bfl_list[i]; 2399 break; 2400 2401 case DLT_IEEE802_11_RADIO: 2402 /* 2403 * 802.11 with radiotap. 2404 * 2405 * Offer this, and select it as the new mode. 2406 */ 2407 new_dlt = bdlp->bfl_list[i]; 2408 break; 2409 2410 default: 2411 /* 2412 * Not 802.11. 2413 */ 2414 break; 2415 } 2416 } 2417 2418 return (new_dlt); 2419 } 2420 #endif /* defined(BIOCGDLTLIST) && (defined(__APPLE__) || defined(HAVE_BSD_IEEE80211)) */ 2421 2422 #if defined(__APPLE__) && defined(BIOCGDLTLIST) 2423 /* 2424 * Remove DLT_EN10MB from the list of DLT_ values, as we're in monitor mode, 2425 * and DLT_EN10MB isn't supported in monitor mode. 2426 */ 2427 static void 2428 remove_en(pcap_t *p) 2429 { 2430 int i, j; 2431 2432 /* 2433 * Scan the list of DLT_ values and discard DLT_EN10MB. 2434 */ 2435 j = 0; 2436 for (i = 0; i < p->dlt_count; i++) { 2437 switch (p->dlt_list[i]) { 2438 2439 case DLT_EN10MB: 2440 /* 2441 * Don't offer this one. 2442 */ 2443 continue; 2444 2445 default: 2446 /* 2447 * Just copy this mode over. 2448 */ 2449 break; 2450 } 2451 2452 /* 2453 * Copy this DLT_ value to its new position. 2454 */ 2455 p->dlt_list[j] = p->dlt_list[i]; 2456 j++; 2457 } 2458 2459 /* 2460 * Set the DLT_ count to the number of entries we copied. 2461 */ 2462 p->dlt_count = j; 2463 } 2464 2465 /* 2466 * Remove 802.11 link-layer types from the list of DLT_ values, as 2467 * we're not in monitor mode, and those DLT_ values will switch us 2468 * to monitor mode. 2469 */ 2470 static void 2471 remove_802_11(pcap_t *p) 2472 { 2473 int i, j; 2474 2475 /* 2476 * Scan the list of DLT_ values and discard 802.11 values. 2477 */ 2478 j = 0; 2479 for (i = 0; i < p->dlt_count; i++) { 2480 switch (p->dlt_list[i]) { 2481 2482 case DLT_IEEE802_11: 2483 case DLT_PRISM_HEADER: 2484 case DLT_AIRONET_HEADER: 2485 case DLT_IEEE802_11_RADIO: 2486 case DLT_IEEE802_11_RADIO_AVS: 2487 /* 2488 * 802.11. Don't offer this one. 2489 */ 2490 continue; 2491 2492 default: 2493 /* 2494 * Just copy this mode over. 2495 */ 2496 break; 2497 } 2498 2499 /* 2500 * Copy this DLT_ value to its new position. 2501 */ 2502 p->dlt_list[j] = p->dlt_list[i]; 2503 j++; 2504 } 2505 2506 /* 2507 * Set the DLT_ count to the number of entries we copied. 2508 */ 2509 p->dlt_count = j; 2510 } 2511 #endif /* defined(__APPLE__) && defined(BIOCGDLTLIST) */ 2512 2513 static int 2514 pcap_setfilter_bpf(pcap_t *p, struct bpf_program *fp) 2515 { 2516 /* 2517 * Free any user-mode filter we might happen to have installed. 2518 */ 2519 pcap_freecode(&p->fcode); 2520 2521 /* 2522 * Try to install the kernel filter. 2523 */ 2524 if (ioctl(p->fd, BIOCSETF, (caddr_t)fp) == 0) { 2525 /* 2526 * It worked. 2527 */ 2528 p->md.use_bpf = 1; /* filtering in the kernel */ 2529 2530 /* 2531 * Discard any previously-received packets, as they might 2532 * have passed whatever filter was formerly in effect, but 2533 * might not pass this filter (BIOCSETF discards packets 2534 * buffered in the kernel, so you can lose packets in any 2535 * case). 2536 */ 2537 p->cc = 0; 2538 return (0); 2539 } 2540 2541 /* 2542 * We failed. 2543 * 2544 * If it failed with EINVAL, that's probably because the program 2545 * is invalid or too big. Validate it ourselves; if we like it 2546 * (we currently allow backward branches, to support protochain), 2547 * run it in userland. (There's no notion of "too big" for 2548 * userland.) 2549 * 2550 * Otherwise, just give up. 2551 * XXX - if the copy of the program into the kernel failed, 2552 * we will get EINVAL rather than, say, EFAULT on at least 2553 * some kernels. 2554 */ 2555 if (errno != EINVAL) { 2556 snprintf(p->errbuf, PCAP_ERRBUF_SIZE, "BIOCSETF: %s", 2557 pcap_strerror(errno)); 2558 return (-1); 2559 } 2560 2561 /* 2562 * install_bpf_program() validates the program. 2563 * 2564 * XXX - what if we already have a filter in the kernel? 2565 */ 2566 if (install_bpf_program(p, fp) < 0) 2567 return (-1); 2568 p->md.use_bpf = 0; /* filtering in userland */ 2569 return (0); 2570 } 2571 2572 /* 2573 * Set direction flag: Which packets do we accept on a forwarding 2574 * single device? IN, OUT or both? 2575 */ 2576 static int 2577 pcap_setdirection_bpf(pcap_t *p, pcap_direction_t d) 2578 { 2579 #if defined(BIOCSDIRECTION) 2580 u_int direction; 2581 2582 direction = (d == PCAP_D_IN) ? BPF_D_IN : 2583 ((d == PCAP_D_OUT) ? BPF_D_OUT : BPF_D_INOUT); 2584 if (ioctl(p->fd, BIOCSDIRECTION, &direction) == -1) { 2585 (void) snprintf(p->errbuf, sizeof(p->errbuf), 2586 "Cannot set direction to %s: %s", 2587 (d == PCAP_D_IN) ? "PCAP_D_IN" : 2588 ((d == PCAP_D_OUT) ? "PCAP_D_OUT" : "PCAP_D_INOUT"), 2589 strerror(errno)); 2590 return (-1); 2591 } 2592 return (0); 2593 #elif defined(BIOCSSEESENT) 2594 u_int seesent; 2595 2596 /* 2597 * We don't support PCAP_D_OUT. 2598 */ 2599 if (d == PCAP_D_OUT) { 2600 snprintf(p->errbuf, sizeof(p->errbuf), 2601 "Setting direction to PCAP_D_OUT is not supported on BPF"); 2602 return -1; 2603 } 2604 2605 seesent = (d == PCAP_D_INOUT); 2606 if (ioctl(p->fd, BIOCSSEESENT, &seesent) == -1) { 2607 (void) snprintf(p->errbuf, sizeof(p->errbuf), 2608 "Cannot set direction to %s: %s", 2609 (d == PCAP_D_INOUT) ? "PCAP_D_INOUT" : "PCAP_D_IN", 2610 strerror(errno)); 2611 return (-1); 2612 } 2613 return (0); 2614 #else 2615 (void) snprintf(p->errbuf, sizeof(p->errbuf), 2616 "This system doesn't support BIOCSSEESENT, so the direction can't be set"); 2617 return (-1); 2618 #endif 2619 } 2620 2621 static int 2622 pcap_set_datalink_bpf(pcap_t *p, int dlt) 2623 { 2624 #ifdef BIOCSDLT 2625 if (ioctl(p->fd, BIOCSDLT, &dlt) == -1) { 2626 (void) snprintf(p->errbuf, sizeof(p->errbuf), 2627 "Cannot set DLT %d: %s", dlt, strerror(errno)); 2628 return (-1); 2629 } 2630 #endif 2631 return (0); 2632 } 2633