1 /* $OpenBSD: tcpdump.c,v 1.94 2020/08/17 06:29:29 dlg 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 Bflag; /* BPF fildrop setting */ 65 int dflag; /* print filter code */ 66 int eflag; /* print ethernet header */ 67 int fflag; /* don't translate "foreign" IP address */ 68 int Iflag; /* include interface in output */ 69 int Lflag; /* List available link types */ 70 int nflag; /* leave addresses as numbers */ 71 int Nflag; /* remove domains from printed host names */ 72 int Oflag = 1; /* run filter code optimizer */ 73 int oflag; /* print passive OS fingerprints */ 74 int pflag; /* don't go promiscuous */ 75 int qflag; /* quick (shorter) output */ 76 int Sflag; /* print raw TCP sequence numbers */ 77 int tflag = 1; /* print packet arrival time */ 78 int vflag; /* verbose */ 79 int xflag; /* print packet in hex */ 80 int Xflag; /* print packet in emacs-hexl style */ 81 82 int packettype; 83 84 char *program_name; 85 char *device = NULL; 86 87 int32_t thiszone; /* seconds offset from gmt to local time */ 88 89 extern volatile pid_t child_pid; 90 91 /* Externs */ 92 extern void bpf_dump(struct bpf_program *, int); 93 extern int esp_init(char *); 94 95 /* Forwards */ 96 void cleanup(int); 97 void gotchld(int); 98 extern __dead void usage(void); 99 100 /* Length of saved portion of packet. */ 101 int snaplen = 0; 102 103 struct printer { 104 pcap_handler f; 105 int type; 106 }; 107 108 /* XXX needed if using old bpf.h */ 109 #ifndef DLT_ATM_RFC1483 110 #define DLT_ATM_RFC1483 11 111 #endif 112 113 static struct printer printers[] = { 114 { ether_if_print, DLT_EN10MB }, 115 { ether_if_print, DLT_IEEE802 }, 116 { sl_if_print, DLT_SLIP }, 117 { sl_bsdos_if_print, DLT_SLIP_BSDOS }, 118 { ppp_if_print, DLT_PPP }, 119 { ppp_hdlc_if_print, DLT_PPP_SERIAL }, 120 { fddi_if_print, DLT_FDDI }, 121 { null_if_print, DLT_NULL }, 122 { raw_if_print, DLT_RAW }, 123 { atm_if_print, DLT_ATM_RFC1483 }, 124 { loop_if_print, DLT_LOOP }, 125 { enc_if_print, DLT_ENC }, 126 { pflog_if_print, DLT_PFLOG }, 127 { pfsync_if_print, DLT_PFSYNC }, 128 { ppp_ether_if_print, DLT_PPP_ETHER }, 129 { ieee802_11_if_print, DLT_IEEE802_11 }, 130 { ieee802_11_radio_if_print, DLT_IEEE802_11_RADIO }, 131 { ofp_if_print, DLT_OPENFLOW }, 132 { usbpcap_if_print, DLT_USBPCAP }, 133 { NULL, 0 }, 134 }; 135 136 static pcap_handler 137 lookup_printer(int type) 138 { 139 struct printer *p; 140 141 for (p = printers; p->f; ++p) { 142 if (type == p->type) 143 return p->f; 144 } 145 146 error("unknown data link type 0x%x", type); 147 /* NOTREACHED */ 148 } 149 150 static int 151 init_pfosfp(void) 152 { 153 pf_osfp_initialize(); 154 if (pfctl_file_fingerprints(-1, 155 PF_OPT_QUIET|PF_OPT_NOACTION, PF_OSFP_FILE) == 0) 156 return 1; 157 return 0; 158 } 159 160 static pcap_t *pd; 161 162 /* Multiple DLT support */ 163 void pcap_list_linktypes(pcap_t *); 164 void pcap_print_linktype(u_int); 165 166 void 167 pcap_print_linktype(u_int dlt) 168 { 169 const char *name; 170 171 if ((name = pcap_datalink_val_to_name(dlt)) != NULL) 172 fprintf(stderr, "%s\n", name); 173 else 174 fprintf(stderr, "<unknown: %u>\n", dlt); 175 } 176 177 void 178 pcap_list_linktypes(pcap_t *p) 179 { 180 int fd = p->fd; 181 u_int n; 182 183 #define MAXDLT 100 184 185 u_int dltlist[MAXDLT]; 186 struct bpf_dltlist dl = {MAXDLT, dltlist}; 187 188 if (fd < 0) 189 error("Invalid bpf descriptor"); 190 191 if (ioctl(fd, BIOCGDLTLIST, &dl) == -1) 192 err(1, "BIOCGDLTLIST"); 193 194 if (dl.bfl_len > MAXDLT) 195 error("Invalid number of linktypes: %u", dl.bfl_len); 196 197 fprintf(stderr, "%d link type%s supported:\n", dl.bfl_len, 198 dl.bfl_len == 1 ? "" : "s"); 199 200 for (n = 0; n < dl.bfl_len; n++) { 201 fprintf(stderr, "\t"); 202 pcap_print_linktype(dltlist[n]); 203 } 204 } 205 206 int 207 main(int argc, char **argv) 208 { 209 int cnt = -1, op, i; 210 bpf_u_int32 localnet, netmask; 211 char *cp, *infile = NULL, *RFileName = NULL; 212 char ebuf[PCAP_ERRBUF_SIZE], *WFileName = NULL; 213 pcap_handler printer; 214 struct bpf_program *fcode; 215 u_char *pcap_userdata; 216 u_int dirfilt = 0, dlt = (u_int) -1; 217 const char *errstr; 218 219 if ((cp = strrchr(argv[0], '/')) != NULL) 220 program_name = cp + 1; 221 else 222 program_name = argv[0]; 223 224 /* '-P' used internally, exec privileged portion */ 225 if (argc >= 2 && strcmp("-P", argv[1]) == 0) 226 priv_exec(argc, argv); 227 228 if (priv_init(argc, argv)) 229 error("Failed to setup privsep"); 230 231 /* state: STATE_INIT */ 232 233 opterr = 0; 234 while ((op = getopt(argc, argv, 235 "AaB:c:D:deE:fF:i:IlLnNOopqr:s:StT:vw:xXy:Y")) != -1) 236 switch (op) { 237 238 case 'A': 239 xflag = 1; 240 Aflag = 1; 241 break; 242 243 case 'a': 244 aflag = 1; 245 break; 246 247 case 'B': 248 if (strcasecmp(optarg, "pass") == 0) 249 Bflag = BPF_FILDROP_PASS; 250 else if (strcasecmp(optarg, "capture") == 0) 251 Bflag = BPF_FILDROP_CAPTURE; 252 else if (strcasecmp(optarg, "drop") == 0) 253 Bflag = BPF_FILDROP_DROP; 254 else { 255 error("invalid BPF fildrop option: %s", 256 optarg); 257 } 258 break; 259 260 case 'c': 261 cnt = strtonum(optarg, 1, INT_MAX, &errstr); 262 if (errstr) 263 error("invalid packet count %s: %s", 264 optarg, errstr); 265 break; 266 267 case 'D': 268 if (strcasecmp(optarg, "in") == 0) 269 dirfilt = BPF_DIRECTION_OUT; 270 else if (strcasecmp(optarg, "out") == 0) 271 dirfilt = BPF_DIRECTION_IN; 272 else 273 error("invalid traffic direction %s", optarg); 274 break; 275 276 case 'd': 277 ++dflag; 278 break; 279 case 'e': 280 eflag = 1; 281 break; 282 283 case 'f': 284 fflag = 1; 285 break; 286 287 case 'F': 288 infile = optarg; 289 break; 290 291 case 'i': 292 device = optarg; 293 break; 294 295 case 'I': 296 Iflag = 1; 297 break; 298 299 case 'l': 300 setvbuf(stdout, NULL, _IOLBF, 0); 301 break; 302 case 'L': 303 Lflag = 1; 304 break; 305 case 'n': 306 nflag = 1; 307 break; 308 309 case 'N': 310 Nflag = 1; 311 break; 312 313 case 'O': 314 Oflag = 0; 315 break; 316 317 case 'o': 318 oflag = 1; 319 break; 320 321 case 'p': 322 pflag = 1; 323 break; 324 325 case 'q': 326 qflag = 1; 327 break; 328 329 case 'r': 330 RFileName = optarg; 331 break; 332 333 case 's': 334 snaplen = strtonum(optarg, 1, INT_MAX, &errstr); 335 if (errstr) 336 error("invalid snaplen %s: %s", optarg, errstr); 337 break; 338 339 case 'S': 340 Sflag = 1; 341 break; 342 343 case 't': 344 --tflag; 345 break; 346 347 case 'T': 348 if (strcasecmp(optarg, "vat") == 0) 349 packettype = PT_VAT; 350 else if (strcasecmp(optarg, "wb") == 0) 351 packettype = PT_WB; 352 else if (strcasecmp(optarg, "rpc") == 0) 353 packettype = PT_RPC; 354 else if (strcasecmp(optarg, "rtp") == 0) 355 packettype = PT_RTP; 356 else if (strcasecmp(optarg, "rtcp") == 0) 357 packettype = PT_RTCP; 358 else if (strcasecmp(optarg, "cnfp") == 0) 359 packettype = PT_CNFP; 360 else if (strcasecmp(optarg, "vrrp") == 0) 361 packettype = PT_VRRP; 362 else if (strcasecmp(optarg, "tcp") == 0) 363 packettype = PT_TCP; 364 else if (strcasecmp(optarg, "gre") == 0) 365 packettype = PT_GRE; 366 else if (strcasecmp(optarg, "vxlan") == 0) 367 packettype = PT_VXLAN; 368 else if (strcasecmp(optarg, "geneve") == 0) 369 packettype = PT_GENEVE; 370 else if (strcasecmp(optarg, "erspan") == 0) 371 packettype = PT_ERSPAN; 372 else if (strcasecmp(optarg, "mpls") == 0) 373 packettype = PT_MPLS; 374 else if (strcasecmp(optarg, "tftp") == 0) 375 packettype = PT_TFTP; 376 else if (strcasecmp(optarg, "wg") == 0) 377 packettype = PT_WIREGUARD; 378 else if (strcasecmp(optarg, "sack") == 0) 379 /* 380 * kept for compatibility; DEFAULT_SNAPLEN 381 * used to be too short to capture SACK. 382 */ 383 ; 384 else 385 error("unknown packet type `%s'", optarg); 386 break; 387 388 case 'v': 389 ++vflag; 390 break; 391 392 case 'w': 393 WFileName = optarg; 394 break; 395 #ifdef YYDEBUG 396 case 'Y': 397 { 398 /* Undocumented flag */ 399 extern int yydebug; 400 yydebug = 1; 401 } 402 break; 403 #endif 404 case 'y': 405 i = pcap_datalink_name_to_val(optarg); 406 if (i < 0) 407 error("invalid data link type: %s", optarg); 408 dlt = (u_int)i; 409 break; 410 411 case 'x': 412 xflag = 1; 413 break; 414 415 case 'X': 416 Xflag = 1; 417 xflag = 1; 418 break; 419 420 case 'E': 421 if (esp_init(optarg) < 0) 422 error("bad esp specification `%s'", optarg); 423 break; 424 425 default: 426 usage(); 427 /* NOTREACHED */ 428 } 429 430 if (snaplen == 0) { 431 switch (dlt) { 432 case DLT_IEEE802_11: 433 snaplen = IEEE802_11_SNAPLEN; 434 break; 435 case DLT_IEEE802_11_RADIO: 436 snaplen = IEEE802_11_RADIO_SNAPLEN; 437 break; 438 default: 439 snaplen = DEFAULT_SNAPLEN; 440 break; 441 } 442 } 443 444 if (aflag && nflag) 445 error("-a and -n options are incompatible"); 446 447 if (RFileName != NULL) { 448 pd = priv_pcap_offline(RFileName, ebuf); 449 if (pd == NULL) 450 error("%s", ebuf); 451 /* state: STATE_BPF */ 452 localnet = 0; 453 netmask = 0; 454 if (fflag != 0) 455 error("-f and -r options are incompatible"); 456 } else { 457 if (device == NULL) { 458 device = pcap_lookupdev(ebuf); 459 if (device == NULL) 460 error("%s", ebuf); 461 } 462 pd = priv_pcap_live(device, snaplen, !pflag, 1000, ebuf, 463 dlt, dirfilt, Bflag); 464 if (pd == NULL) 465 error("%s", ebuf); 466 467 /* state: STATE_BPF */ 468 if (pcap_lookupnet(device, &localnet, &netmask, ebuf)) { 469 if (fflag) 470 warning("%s", ebuf); 471 localnet = 0; 472 netmask = 0; 473 } 474 } 475 i = pcap_snapshot(pd); 476 if (snaplen < i) { 477 warning("snaplen raised from %d to %d", snaplen, i); 478 snaplen = i; 479 } 480 481 if (Lflag) { 482 pcap_list_linktypes(pd); 483 exit(0); 484 } 485 486 fcode = priv_pcap_setfilter(pd, Oflag, netmask); 487 /* state: STATE_FILTER */ 488 if (fcode == NULL) 489 error("%s", pcap_geterr(pd)); 490 if (dflag) { 491 bpf_dump(fcode, dflag); 492 exit(0); 493 } 494 if (oflag) 495 oflag = init_pfosfp(); 496 init_addrtoname(localnet, netmask); 497 498 if (WFileName) { 499 pcap_dumper_t *p; 500 501 p = priv_pcap_dump_open(pd, WFileName); 502 /* state: STATE_RUN */ 503 if (p == NULL) 504 error("%s", pcap_geterr(pd)); 505 { 506 FILE *fp = (FILE *)p; /* XXX touching pcap guts! */ 507 fflush(fp); 508 setvbuf(fp, NULL, _IONBF, 0); 509 } 510 printer = pcap_dump; 511 pcap_userdata = (u_char *)p; 512 } else { 513 printer = lookup_printer(pcap_datalink(pd)); 514 pcap_userdata = NULL; 515 priv_init_done(); 516 /* state: STATE_RUN */ 517 } 518 if (RFileName == NULL) { 519 (void)fprintf(stderr, "%s: listening on %s, link-type ", 520 program_name, device); 521 pcap_print_linktype(pd->linktype); 522 (void)fflush(stderr); 523 } 524 525 if (tflag > 0) 526 thiszone = gmt2local(0); 527 528 if (pledge("stdio", NULL) == -1) 529 err(1, "pledge"); 530 531 if (pcap_loop(pd, cnt, printer, pcap_userdata) < 0) { 532 (void)fprintf(stderr, "%s: pcap_loop: %s\n", 533 program_name, pcap_geterr(pd)); 534 exit(1); 535 } 536 pcap_close(pd); 537 exit(0); 538 } 539 540 /* make a clean exit on interrupts */ 541 void 542 cleanup(int signo) 543 { 544 struct pcap_stat stat; 545 sigset_t allsigs; 546 547 sigfillset(&allsigs); 548 sigprocmask(SIG_BLOCK, &allsigs, NULL); 549 550 /* Can't print the summary if reading from a savefile */ 551 dprintf(STDERR_FILENO, "\n"); 552 if (pd != NULL && pcap_file(pd) == NULL) { 553 if (priv_pcap_stats(&stat) < 0) { 554 dprintf(STDERR_FILENO, 555 "pcap_stats: %s\n", pcap_geterr(pd)); 556 } else { 557 dprintf(STDERR_FILENO, 558 "%u packets received by filter\n", stat.ps_recv); 559 dprintf(STDERR_FILENO, 560 "%u packets dropped by kernel\n", stat.ps_drop); 561 } 562 } 563 _exit(0); 564 } 565 566 void 567 gotchld(int signo) 568 { 569 pid_t pid; 570 int status; 571 int save_err = errno; 572 573 do { 574 pid = waitpid(child_pid, &status, WNOHANG); 575 if (pid > 0 && (WIFEXITED(status) || WIFSIGNALED(status))) 576 cleanup(0); 577 } while (pid == -1 && errno == EINTR); 578 579 if (pid == -1) 580 _exit(1); 581 582 errno = save_err; 583 } 584 585 /* dump the buffer in `emacs-hexl' style */ 586 void 587 default_print_hexl(const u_char *cp, unsigned int length) 588 { 589 unsigned int i, j, jm; 590 int c; 591 char ln[128], buf[128]; 592 593 printf("\n"); 594 for (i = 0; i < length; i += 0x10) { 595 snprintf(ln, sizeof(ln), " %04x: ", (unsigned int)i); 596 jm = length - i; 597 jm = jm > 16 ? 16 : jm; 598 599 for (j = 0; j < jm; j++) { 600 if ((j % 2) == 1) 601 snprintf(buf, sizeof(buf), "%02x ", 602 (unsigned int)cp[i+j]); 603 else 604 snprintf(buf, sizeof(buf), "%02x", 605 (unsigned int)cp[i+j]); 606 strlcat(ln, buf, sizeof ln); 607 } 608 for (; j < 16; j++) { 609 if ((j % 2) == 1) 610 snprintf(buf, sizeof buf, " "); 611 else 612 snprintf(buf, sizeof buf, " "); 613 strlcat(ln, buf, sizeof ln); 614 } 615 616 strlcat(ln, " ", sizeof ln); 617 for (j = 0; j < jm; j++) { 618 c = cp[i+j]; 619 c = isprint(c) ? c : '.'; 620 buf[0] = c; 621 buf[1] = '\0'; 622 strlcat(ln, buf, sizeof ln); 623 } 624 printf("%s\n", ln); 625 } 626 } 627 628 /* dump the text from the buffer */ 629 void 630 default_print_ascii(const u_char *cp, unsigned int length) 631 { 632 int c, i; 633 634 printf("\n"); 635 for (i = 0; i < length; i++) { 636 c = cp[i]; 637 if (isprint(c) || c == '\t' || c == '\n' || c == '\r') 638 putchar(c); 639 else 640 putchar('.'); 641 } 642 } 643 644 /* Like default_print() but data need not be aligned */ 645 void 646 default_print_unaligned(const u_char *cp, u_int length) 647 { 648 u_int i, s; 649 int nshorts; 650 651 if (Xflag) { 652 /* dump the buffer in `emacs-hexl' style */ 653 default_print_hexl(cp, length); 654 } else if (Aflag) { 655 /* dump the text in the buffer */ 656 default_print_ascii(cp, length); 657 } else { 658 /* dump the buffer in old tcpdump style */ 659 nshorts = (u_int) length / sizeof(u_short); 660 i = 0; 661 while (--nshorts >= 0) { 662 if ((i++ % 8) == 0) 663 printf("\n\t\t\t"); 664 s = *cp++; 665 printf(" %02x%02x", s, *cp++); 666 } 667 if (length & 1) { 668 if ((i % 8) == 0) 669 printf("\n\t\t\t"); 670 printf(" %02x", *cp); 671 } 672 } 673 } 674 675 void 676 default_print(const u_char *bp, u_int length) 677 { 678 const u_short *sp; 679 u_int i; 680 int nshorts; 681 682 if (Xflag) { 683 /* dump the buffer in `emacs-hexl' style */ 684 default_print_hexl(bp, length); 685 } else if (Aflag) { 686 /* dump the text in the buffer */ 687 default_print_ascii(bp, length); 688 } else { 689 /* dump the buffer in old tcpdump style */ 690 if ((long)bp & 1) { 691 default_print_unaligned(bp, length); 692 return; 693 } 694 sp = (u_short *)bp; 695 nshorts = (u_int) length / sizeof(u_short); 696 i = 0; 697 while (--nshorts >= 0) { 698 if ((i++ % 8) == 0) 699 printf("\n\t\t\t"); 700 printf(" %04x", ntohs(*sp++)); 701 } 702 if (length & 1) { 703 if ((i % 8) == 0) 704 printf("\n\t\t\t"); 705 printf(" %02x", *(u_char *)sp); 706 } 707 } 708 } 709 710 void 711 set_slave_signals(void) 712 { 713 setsignal(SIGTERM, cleanup); 714 setsignal(SIGINT, cleanup); 715 setsignal(SIGCHLD, gotchld); 716 setsignal(SIGHUP, cleanup); 717 } 718 719 __dead void 720 usage(void) 721 { 722 (void)fprintf(stderr, 723 "Usage: %s [-AadefILlNnOopqStvXx] [-B fildrop] [-c count] [-D direction]\n", 724 program_name); 725 (void)fprintf(stderr, 726 "\t [-E [espalg:]espkey] [-F file] [-i interface] [-r file]\n"); 727 (void)fprintf(stderr, 728 "\t [-s snaplen] [-T type] [-w file] [-y datalinktype] [expression]\n"); 729 exit(1); 730 } 731