1 /* $OpenBSD: tcpdump.c,v 1.78 2015/12/22 21:01:07 mmcc Exp $ */ 2 3 /* 4 * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997 5 * The Regents of the University of California. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that: (1) source code distributions 9 * retain the above copyright notice and this paragraph in its entirety, (2) 10 * distributions including binary code include the above copyright notice and 11 * this paragraph in its entirety in the documentation or other materials 12 * provided with the distribution, and (3) all advertising materials mentioning 13 * features or use of this software display the following acknowledgement: 14 * ``This product includes software developed by the University of California, 15 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of 16 * the University nor the names of its contributors may be used to endorse 17 * or promote products derived from this software without specific prior 18 * written permission. 19 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED 20 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF 21 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 22 */ 23 24 /* 25 * tcpdump - monitor tcp/ip traffic on an ethernet. 26 * 27 * First written in 1987 by Van Jacobson, Lawrence Berkeley Laboratory. 28 * Mercilessly hacked and occasionally improved since then via the 29 * combined efforts of Van, Steve McCanne and Craig Leres of LBL. 30 */ 31 32 #include <sys/types.h> 33 #include <sys/time.h> 34 #include <sys/ioctl.h> 35 #include <sys/wait.h> 36 37 #include <netinet/in.h> 38 39 #include <pcap.h> 40 #include <signal.h> 41 #include <stdio.h> 42 #include <stdlib.h> 43 #include <string.h> 44 #include <unistd.h> 45 #include <limits.h> 46 #include <ctype.h> 47 #include <err.h> 48 #include <errno.h> 49 50 #include "interface.h" 51 #include "addrtoname.h" 52 #include "setsignal.h" 53 #include "gmt2local.h" 54 55 #include <sys/socket.h> 56 #include <net/if.h> 57 #include <net/pfvar.h> 58 #include "pfctl.h" 59 #include "pfctl_parser.h" 60 #include "privsep.h" 61 62 int Aflag; /* dump ascii */ 63 int aflag; /* translate network and broadcast addresses */ 64 int dflag; /* print filter code */ 65 int eflag; /* print ethernet header */ 66 int fflag; /* don't translate "foreign" IP address */ 67 int Iflag; /* include interface in output */ 68 int Lflag; /* List available link types */ 69 int nflag; /* leave addresses as numbers */ 70 int Nflag; /* remove domains from printed host names */ 71 int Oflag = 1; /* run filter code optimizer */ 72 int oflag; /* print passive OS fingerprints */ 73 int pflag; /* don't go promiscuous */ 74 int qflag; /* quick (shorter) output */ 75 int Sflag; /* print raw TCP sequence numbers */ 76 int tflag = 1; /* print packet arrival time */ 77 int vflag; /* verbose */ 78 int xflag; /* print packet in hex */ 79 int Xflag; /* print packet in emacs-hexl style */ 80 81 int packettype; 82 83 char *program_name; 84 char *device = NULL; 85 86 int32_t thiszone; /* seconds offset from gmt to local time */ 87 88 extern volatile pid_t child_pid; 89 90 /* Externs */ 91 extern void bpf_dump(struct bpf_program *, int); 92 extern int esp_init(char *); 93 94 /* Forwards */ 95 void cleanup(int); 96 void gotchld(int); 97 extern __dead void usage(void); 98 99 /* Length of saved portion of packet. */ 100 int snaplen = 0; 101 102 struct printer { 103 pcap_handler f; 104 int type; 105 }; 106 107 /* XXX needed if using old bpf.h */ 108 #ifndef DLT_ATM_RFC1483 109 #define DLT_ATM_RFC1483 11 110 #endif 111 112 static struct printer printers[] = { 113 { ether_if_print, DLT_EN10MB }, 114 { ether_if_print, DLT_IEEE802 }, 115 { sl_if_print, DLT_SLIP }, 116 { sl_bsdos_if_print, DLT_SLIP_BSDOS }, 117 { ppp_if_print, DLT_PPP }, 118 { fddi_if_print, DLT_FDDI }, 119 { null_if_print, DLT_NULL }, 120 { raw_if_print, DLT_RAW }, 121 { atm_if_print, DLT_ATM_RFC1483 }, 122 { loop_if_print, DLT_LOOP }, 123 { enc_if_print, DLT_ENC }, 124 { pflog_if_print, DLT_PFLOG }, 125 { pfsync_if_print, DLT_PFSYNC }, 126 { ppp_ether_if_print, DLT_PPP_ETHER }, 127 { ieee802_11_if_print, DLT_IEEE802_11 }, 128 { ieee802_11_radio_if_print, DLT_IEEE802_11_RADIO }, 129 { NULL, 0 }, 130 }; 131 132 static pcap_handler 133 lookup_printer(int type) 134 { 135 struct printer *p; 136 137 for (p = printers; p->f; ++p) { 138 if (type == p->type) 139 return p->f; 140 } 141 142 error("unknown data link type 0x%x", type); 143 /* NOTREACHED */ 144 } 145 146 static int 147 init_pfosfp(void) 148 { 149 pf_osfp_initialize(); 150 if (pfctl_file_fingerprints(-1, 151 PF_OPT_QUIET|PF_OPT_NOACTION, PF_OSFP_FILE) == 0) 152 return 1; 153 return 0; 154 } 155 156 static pcap_t *pd; 157 158 /* Multiple DLT support */ 159 void pcap_list_linktypes(pcap_t *); 160 void pcap_print_linktype(u_int); 161 162 void 163 pcap_print_linktype(u_int dlt) 164 { 165 const char *name; 166 167 if ((name = pcap_datalink_val_to_name(dlt)) != NULL) 168 fprintf(stderr, "%s\n", name); 169 else 170 fprintf(stderr, "<unknown: %u>\n", dlt); 171 } 172 173 void 174 pcap_list_linktypes(pcap_t *p) 175 { 176 int fd = p->fd; 177 u_int n; 178 179 #define MAXDLT 100 180 181 u_int dltlist[MAXDLT]; 182 struct bpf_dltlist dl = {MAXDLT, dltlist}; 183 184 if (fd < 0) 185 error("Invalid bpf descriptor"); 186 187 if (ioctl(fd, BIOCGDLTLIST, &dl) < 0) 188 err(1, "BIOCGDLTLIST"); 189 190 if (dl.bfl_len > MAXDLT) 191 error("Invalid number of linktypes: %u", dl.bfl_len); 192 193 fprintf(stderr, "%d link type%s supported:\n", dl.bfl_len, 194 dl.bfl_len == 1 ? "" : "s"); 195 196 for (n = 0; n < dl.bfl_len; n++) { 197 fprintf(stderr, "\t"); 198 pcap_print_linktype(dltlist[n]); 199 } 200 } 201 202 int 203 main(int argc, char **argv) 204 { 205 int cnt = -1, op, i; 206 bpf_u_int32 localnet, netmask; 207 char *cp, *infile = NULL, *RFileName = NULL; 208 char ebuf[PCAP_ERRBUF_SIZE], *WFileName = NULL; 209 pcap_handler printer; 210 struct bpf_program *fcode; 211 u_char *pcap_userdata; 212 u_int dirfilt = 0, dlt = (u_int) -1; 213 const char *errstr; 214 215 if ((cp = strrchr(argv[0], '/')) != NULL) 216 program_name = cp + 1; 217 else 218 program_name = argv[0]; 219 220 if (priv_init(argc, argv)) 221 error("Failed to setup privsep"); 222 223 /* state: STATE_INIT */ 224 225 opterr = 0; 226 while ((op = getopt(argc, argv, 227 "Aac:D:deE:fF:i:IlLnNOopqr:s:StT:vw:xXy:Y")) != -1) 228 switch (op) { 229 230 case 'A': 231 xflag = 1; 232 Aflag = 1; 233 break; 234 235 case 'a': 236 aflag = 1; 237 break; 238 239 case 'c': 240 cnt = strtonum(optarg, 1, INT_MAX, &errstr); 241 if (errstr) 242 error("invalid packet count %s: %s", 243 optarg, errstr); 244 break; 245 246 case 'D': 247 if (strcasecmp(optarg, "in") == 0) 248 dirfilt = BPF_DIRECTION_OUT; 249 else if (strcasecmp(optarg, "out") == 0) 250 dirfilt = BPF_DIRECTION_IN; 251 else 252 error("invalid traffic direction %s", optarg); 253 break; 254 255 case 'd': 256 ++dflag; 257 break; 258 case 'e': 259 eflag = 1; 260 break; 261 262 case 'f': 263 fflag = 1; 264 break; 265 266 case 'F': 267 infile = optarg; 268 break; 269 270 case 'i': 271 device = optarg; 272 break; 273 274 case 'I': 275 Iflag = 1; 276 break; 277 278 case 'l': 279 setvbuf(stdout, NULL, _IOLBF, 0); 280 break; 281 case 'L': 282 Lflag = 1; 283 break; 284 case 'n': 285 nflag = 1; 286 break; 287 288 case 'N': 289 Nflag = 1; 290 break; 291 292 case 'O': 293 Oflag = 0; 294 break; 295 296 case 'o': 297 oflag = 1; 298 break; 299 300 case 'p': 301 pflag = 1; 302 break; 303 304 case 'q': 305 qflag = 1; 306 break; 307 308 case 'r': 309 RFileName = optarg; 310 break; 311 312 case 's': 313 snaplen = strtonum(optarg, 1, INT_MAX, &errstr); 314 if (errstr) 315 error("invalid snaplen %s: %s", optarg, errstr); 316 break; 317 318 case 'S': 319 Sflag = 1; 320 break; 321 322 case 't': 323 --tflag; 324 break; 325 326 case 'T': 327 if (strcasecmp(optarg, "vat") == 0) 328 packettype = PT_VAT; 329 else if (strcasecmp(optarg, "wb") == 0) 330 packettype = PT_WB; 331 else if (strcasecmp(optarg, "rpc") == 0) 332 packettype = PT_RPC; 333 else if (strcasecmp(optarg, "rtp") == 0) 334 packettype = PT_RTP; 335 else if (strcasecmp(optarg, "rtcp") == 0) 336 packettype = PT_RTCP; 337 else if (strcasecmp(optarg, "cnfp") == 0) 338 packettype = PT_CNFP; 339 else if (strcasecmp(optarg, "vrrp") == 0) 340 packettype = PT_VRRP; 341 else if (strcasecmp(optarg, "tcp") == 0) 342 packettype = PT_TCP; 343 else if (strcasecmp(optarg, "sack") == 0) 344 /* 345 * kept for compatibility; DEFAULT_SNAPLEN 346 * used to be too short to capture SACK. 347 */ 348 ; 349 else 350 error("unknown packet type `%s'", optarg); 351 break; 352 353 case 'v': 354 ++vflag; 355 break; 356 357 case 'w': 358 WFileName = optarg; 359 break; 360 #ifdef YYDEBUG 361 case 'Y': 362 { 363 /* Undocumented flag */ 364 extern int yydebug; 365 yydebug = 1; 366 } 367 break; 368 #endif 369 case 'y': 370 i = pcap_datalink_name_to_val(optarg); 371 if (i < 0) 372 error("invalid data link type: %s", optarg); 373 dlt = (u_int)i; 374 break; 375 376 case 'x': 377 xflag = 1; 378 break; 379 380 case 'X': 381 Xflag = 1; 382 xflag = 1; 383 break; 384 385 case 'E': 386 if (esp_init(optarg) < 0) 387 error("bad esp specification `%s'", optarg); 388 break; 389 390 default: 391 usage(); 392 /* NOTREACHED */ 393 } 394 395 if (snaplen == 0) { 396 switch (dlt) { 397 case DLT_IEEE802_11: 398 snaplen = IEEE802_11_SNAPLEN; 399 break; 400 case DLT_IEEE802_11_RADIO: 401 snaplen = IEEE802_11_RADIO_SNAPLEN; 402 break; 403 default: 404 snaplen = DEFAULT_SNAPLEN; 405 break; 406 } 407 } 408 409 if (aflag && nflag) 410 error("-a and -n options are incompatible"); 411 412 if (RFileName != NULL) { 413 pd = priv_pcap_offline(RFileName, ebuf); 414 if (pd == NULL) 415 error("%s", ebuf); 416 /* state: STATE_BPF */ 417 localnet = 0; 418 netmask = 0; 419 if (fflag != 0) 420 error("-f and -r options are incompatible"); 421 } else { 422 if (device == NULL) { 423 device = pcap_lookupdev(ebuf); 424 if (device == NULL) 425 error("%s", ebuf); 426 } 427 pd = priv_pcap_live(device, snaplen, !pflag, 1000, ebuf, 428 dlt, dirfilt); 429 if (pd == NULL) 430 error("%s", ebuf); 431 432 /* state: STATE_BPF */ 433 if (pcap_lookupnet(device, &localnet, &netmask, ebuf)) { 434 if (fflag) 435 warning("%s", ebuf); 436 localnet = 0; 437 netmask = 0; 438 } 439 } 440 i = pcap_snapshot(pd); 441 if (snaplen < i) { 442 warning("snaplen raised from %d to %d", snaplen, i); 443 snaplen = i; 444 } 445 446 if (Lflag) { 447 pcap_list_linktypes(pd); 448 exit(0); 449 } 450 451 fcode = priv_pcap_setfilter(pd, Oflag, netmask); 452 /* state: STATE_FILTER */ 453 if (fcode == NULL) 454 error("%s", pcap_geterr(pd)); 455 if (dflag) { 456 bpf_dump(fcode, dflag); 457 exit(0); 458 } 459 init_addrtoname(localnet, netmask); 460 461 if (WFileName) { 462 pcap_dumper_t *p; 463 464 p = priv_pcap_dump_open(pd, WFileName); 465 /* state: STATE_RUN */ 466 if (p == NULL) 467 error("%s", pcap_geterr(pd)); 468 { 469 FILE *fp = (FILE *)p; /* XXX touching pcap guts! */ 470 fflush(fp); 471 setvbuf(fp, NULL, _IONBF, 0); 472 } 473 printer = pcap_dump; 474 pcap_userdata = (u_char *)p; 475 } else { 476 printer = lookup_printer(pcap_datalink(pd)); 477 pcap_userdata = NULL; 478 priv_init_done(); 479 /* state: STATE_RUN */ 480 } 481 if (RFileName == NULL) { 482 (void)fprintf(stderr, "%s: listening on %s, link-type ", 483 program_name, device); 484 pcap_print_linktype(pd->linktype); 485 (void)fflush(stderr); 486 } 487 488 if (oflag) 489 oflag = init_pfosfp(); 490 if (tflag > 0) 491 thiszone = gmt2local(0); 492 493 if (pledge("stdio", NULL) == -1) 494 err(1, "pledge"); 495 496 if (pcap_loop(pd, cnt, printer, pcap_userdata) < 0) { 497 (void)fprintf(stderr, "%s: pcap_loop: %s\n", 498 program_name, pcap_geterr(pd)); 499 exit(1); 500 } 501 pcap_close(pd); 502 exit(0); 503 } 504 505 /* make a clean exit on interrupts */ 506 void 507 cleanup(int signo) 508 { 509 struct pcap_stat stat; 510 sigset_t allsigs; 511 char buf[1024]; 512 513 sigfillset(&allsigs); 514 sigprocmask(SIG_BLOCK, &allsigs, NULL); 515 516 /* Can't print the summary if reading from a savefile */ 517 (void)write(STDERR_FILENO, "\n", 1); 518 if (pd != NULL && pcap_file(pd) == NULL) { 519 if (priv_pcap_stats(&stat) < 0) { 520 (void)snprintf(buf, sizeof buf, 521 "pcap_stats: %s\n", pcap_geterr(pd)); 522 write(STDERR_FILENO, buf, strlen(buf)); 523 } else { 524 (void)snprintf(buf, sizeof buf, 525 "%u packets received by filter\n", stat.ps_recv); 526 write(STDERR_FILENO, buf, strlen(buf)); 527 (void)snprintf(buf, sizeof buf, 528 "%u packets dropped by kernel\n", stat.ps_drop); 529 write(STDERR_FILENO, buf, strlen(buf)); 530 } 531 } 532 _exit(0); 533 } 534 535 void 536 gotchld(int signo) 537 { 538 pid_t pid; 539 int status; 540 int save_err = errno; 541 542 do { 543 pid = waitpid(child_pid, &status, WNOHANG); 544 if (pid > 0 && (WIFEXITED(status) || WIFSIGNALED(status))) 545 cleanup(0); 546 } while (pid == -1 && errno == EINTR); 547 548 if (pid == -1) 549 _exit(1); 550 551 errno = save_err; 552 } 553 554 /* dump the buffer in `emacs-hexl' style */ 555 void 556 default_print_hexl(const u_char *cp, unsigned int length) 557 { 558 unsigned int i, j, jm; 559 int c; 560 char ln[128], buf[128]; 561 562 printf("\n"); 563 for (i = 0; i < length; i += 0x10) { 564 snprintf(ln, sizeof(ln), " %04x: ", (unsigned int)i); 565 jm = length - i; 566 jm = jm > 16 ? 16 : jm; 567 568 for (j = 0; j < jm; j++) { 569 if ((j % 2) == 1) 570 snprintf(buf, sizeof(buf), "%02x ", 571 (unsigned int)cp[i+j]); 572 else 573 snprintf(buf, sizeof(buf), "%02x", 574 (unsigned int)cp[i+j]); 575 strlcat(ln, buf, sizeof ln); 576 } 577 for (; j < 16; j++) { 578 if ((j % 2) == 1) 579 snprintf(buf, sizeof buf, " "); 580 else 581 snprintf(buf, sizeof buf, " "); 582 strlcat(ln, buf, sizeof ln); 583 } 584 585 strlcat(ln, " ", sizeof ln); 586 for (j = 0; j < jm; j++) { 587 c = cp[i+j]; 588 c = isprint(c) ? c : '.'; 589 buf[0] = c; 590 buf[1] = '\0'; 591 strlcat(ln, buf, sizeof ln); 592 } 593 printf("%s\n", ln); 594 } 595 } 596 597 /* dump the text from the buffer */ 598 void 599 default_print_ascii(const u_char *cp, unsigned int length) 600 { 601 int c, i; 602 603 printf("\n"); 604 for (i = 0; i < length; i++) { 605 c = cp[i]; 606 if (isprint(c) || c == '\t' || c == '\n' || c == '\r') 607 putchar(c); 608 else 609 putchar('.'); 610 } 611 } 612 613 /* Like default_print() but data need not be aligned */ 614 void 615 default_print_unaligned(const u_char *cp, u_int length) 616 { 617 u_int i, s; 618 int nshorts; 619 620 if (Xflag) { 621 /* dump the buffer in `emacs-hexl' style */ 622 default_print_hexl(cp, length); 623 } else if (Aflag) { 624 /* dump the text in the buffer */ 625 default_print_ascii(cp, length); 626 } else { 627 /* dump the buffer in old tcpdump style */ 628 nshorts = (u_int) length / sizeof(u_short); 629 i = 0; 630 while (--nshorts >= 0) { 631 if ((i++ % 8) == 0) 632 (void)printf("\n\t\t\t"); 633 s = *cp++; 634 (void)printf(" %02x%02x", s, *cp++); 635 } 636 if (length & 1) { 637 if ((i % 8) == 0) 638 (void)printf("\n\t\t\t"); 639 (void)printf(" %02x", *cp); 640 } 641 } 642 } 643 644 void 645 default_print(const u_char *bp, u_int length) 646 { 647 const u_short *sp; 648 u_int i; 649 int nshorts; 650 651 if (Xflag) { 652 /* dump the buffer in `emacs-hexl' style */ 653 default_print_hexl(bp, length); 654 } else if (Aflag) { 655 /* dump the text in the buffer */ 656 default_print_ascii(bp, length); 657 } else { 658 /* dump the buffer in old tcpdump style */ 659 if ((long)bp & 1) { 660 default_print_unaligned(bp, length); 661 return; 662 } 663 sp = (u_short *)bp; 664 nshorts = (u_int) length / sizeof(u_short); 665 i = 0; 666 while (--nshorts >= 0) { 667 if ((i++ % 8) == 0) 668 (void)printf("\n\t\t\t"); 669 (void)printf(" %04x", ntohs(*sp++)); 670 } 671 if (length & 1) { 672 if ((i % 8) == 0) 673 (void)printf("\n\t\t\t"); 674 (void)printf(" %02x", *(u_char *)sp); 675 } 676 } 677 } 678 679 void 680 set_slave_signals(void) 681 { 682 setsignal(SIGTERM, cleanup); 683 setsignal(SIGINT, cleanup); 684 setsignal(SIGCHLD, gotchld); 685 setsignal(SIGHUP, cleanup); 686 } 687 688 __dead void 689 usage(void) 690 { 691 (void)fprintf(stderr, 692 "Usage: %s [-AadefILlNnOopqStvXx] [-c count] [-D direction]\n", 693 program_name); 694 (void)fprintf(stderr, 695 "\t [-E [espalg:]espkey] [-F file] [-i interface] [-r file]\n"); 696 (void)fprintf(stderr, 697 "\t [-s snaplen] [-T type] [-w file] [-y datalinktype] [expression]\n"); 698 exit(1); 699 } 700