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