1 /* $OpenBSD: tcpdump.c,v 1.97 2022/07/09 23:24:44 halex 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_PASS; /* 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, *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:")) != -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 break; 289 290 case 'i': 291 device = optarg; 292 break; 293 294 case 'I': 295 Iflag = 1; 296 break; 297 298 case 'l': 299 setvbuf(stdout, NULL, _IOLBF, 0); 300 break; 301 case 'L': 302 Lflag = 1; 303 break; 304 case 'n': 305 nflag = 1; 306 break; 307 308 case 'N': 309 Nflag = 1; 310 break; 311 312 case 'O': 313 Oflag = 0; 314 break; 315 316 case 'o': 317 oflag = 1; 318 break; 319 320 case 'p': 321 pflag = 1; 322 break; 323 324 case 'q': 325 qflag = 1; 326 break; 327 328 case 'r': 329 RFileName = optarg; 330 break; 331 332 case 's': 333 snaplen = strtonum(optarg, 1, INT_MAX, &errstr); 334 if (errstr) 335 error("invalid snaplen %s: %s", optarg, errstr); 336 break; 337 338 case 'S': 339 Sflag = 1; 340 break; 341 342 case 't': 343 --tflag; 344 break; 345 346 case 'T': 347 if (strcasecmp(optarg, "vat") == 0) 348 packettype = PT_VAT; 349 else if (strcasecmp(optarg, "wb") == 0) 350 packettype = PT_WB; 351 else if (strcasecmp(optarg, "rpc") == 0) 352 packettype = PT_RPC; 353 else if (strcasecmp(optarg, "rtp") == 0) 354 packettype = PT_RTP; 355 else if (strcasecmp(optarg, "rtcp") == 0) 356 packettype = PT_RTCP; 357 else if (strcasecmp(optarg, "cnfp") == 0) 358 packettype = PT_CNFP; 359 else if (strcasecmp(optarg, "vrrp") == 0) 360 packettype = PT_VRRP; 361 else if (strcasecmp(optarg, "tcp") == 0) 362 packettype = PT_TCP; 363 else if (strcasecmp(optarg, "gre") == 0) 364 packettype = PT_GRE; 365 else if (strcasecmp(optarg, "vxlan") == 0) 366 packettype = PT_VXLAN; 367 else if (strcasecmp(optarg, "geneve") == 0) 368 packettype = PT_GENEVE; 369 else if (strcasecmp(optarg, "erspan") == 0) 370 packettype = PT_ERSPAN; 371 else if (strcasecmp(optarg, "mpls") == 0) 372 packettype = PT_MPLS; 373 else if (strcasecmp(optarg, "tftp") == 0) 374 packettype = PT_TFTP; 375 else if (strcasecmp(optarg, "wg") == 0) 376 packettype = PT_WIREGUARD; 377 else if (strcasecmp(optarg, "sack") == 0) 378 /* 379 * kept for compatibility; DEFAULT_SNAPLEN 380 * used to be too short to capture SACK. 381 */ 382 ; 383 else 384 error("unknown packet type `%s'", optarg); 385 break; 386 387 case 'v': 388 ++vflag; 389 break; 390 391 case 'w': 392 WFileName = optarg; 393 break; 394 395 case 'y': 396 i = pcap_datalink_name_to_val(optarg); 397 if (i < 0) 398 error("invalid data link type: %s", optarg); 399 dlt = (u_int)i; 400 break; 401 402 case 'x': 403 xflag = 1; 404 break; 405 406 case 'X': 407 Xflag = 1; 408 xflag = 1; 409 break; 410 411 case 'E': 412 if (esp_init(optarg) < 0) 413 error("bad esp specification `%s'", optarg); 414 break; 415 416 default: 417 usage(); 418 /* NOTREACHED */ 419 } 420 421 if (snaplen == 0) { 422 switch (dlt) { 423 case DLT_IEEE802_11: 424 snaplen = IEEE802_11_SNAPLEN; 425 break; 426 case DLT_IEEE802_11_RADIO: 427 snaplen = IEEE802_11_RADIO_SNAPLEN; 428 break; 429 default: 430 snaplen = DEFAULT_SNAPLEN; 431 break; 432 } 433 } 434 435 if (aflag && nflag) 436 error("-a and -n options are incompatible"); 437 438 if (RFileName != NULL) { 439 pd = priv_pcap_offline(RFileName, ebuf); 440 if (pd == NULL) 441 error("%s", ebuf); 442 /* state: STATE_BPF */ 443 localnet = 0; 444 netmask = 0; 445 if (fflag != 0) 446 error("-f and -r options are incompatible"); 447 } else { 448 if (device == NULL) { 449 device = pcap_lookupdev(ebuf); 450 if (device == NULL) 451 error("%s", ebuf); 452 } 453 pd = priv_pcap_live(device, snaplen, !pflag, 1000, ebuf, 454 dlt, dirfilt, Bflag); 455 if (pd == NULL) 456 error("%s", ebuf); 457 458 /* state: STATE_BPF */ 459 if (pcap_lookupnet(device, &localnet, &netmask, ebuf)) { 460 if (fflag) 461 warning("%s", ebuf); 462 localnet = 0; 463 netmask = 0; 464 } 465 } 466 i = pcap_snapshot(pd); 467 if (snaplen < i) { 468 warning("snaplen raised from %d to %d", snaplen, i); 469 snaplen = i; 470 } 471 472 if (Lflag) { 473 pcap_list_linktypes(pd); 474 exit(0); 475 } 476 477 fcode = priv_pcap_setfilter(pd, Oflag, netmask); 478 /* state: STATE_FILTER */ 479 if (fcode == NULL) 480 error("%s", pcap_geterr(pd)); 481 if (dflag) { 482 bpf_dump(fcode, dflag); 483 exit(0); 484 } 485 if (oflag) 486 oflag = init_pfosfp(); 487 init_addrtoname(localnet, netmask); 488 489 if (WFileName) { 490 pcap_dumper_t *p; 491 492 p = priv_pcap_dump_open(pd, WFileName); 493 /* state: STATE_RUN */ 494 if (p == NULL) 495 error("%s", pcap_geterr(pd)); 496 { 497 FILE *fp = (FILE *)p; /* XXX touching pcap guts! */ 498 fflush(fp); 499 setvbuf(fp, NULL, _IONBF, 0); 500 } 501 printer = pcap_dump; 502 pcap_userdata = (u_char *)p; 503 } else { 504 printer = lookup_printer(pcap_datalink(pd)); 505 pcap_userdata = NULL; 506 priv_init_done(); 507 /* state: STATE_RUN */ 508 } 509 if (RFileName == NULL) { 510 (void)fprintf(stderr, "%s: listening on %s, link-type ", 511 program_name, device); 512 pcap_print_linktype(pd->linktype); 513 (void)fflush(stderr); 514 } 515 516 if (tflag > 0) 517 thiszone = gmt2local(0); 518 519 if (pledge("stdio", NULL) == -1) 520 err(1, "pledge"); 521 522 if (pcap_loop(pd, cnt, printer, pcap_userdata) < 0) { 523 (void)fprintf(stderr, "%s: pcap_loop: %s\n", 524 program_name, pcap_geterr(pd)); 525 exit(1); 526 } 527 pcap_close(pd); 528 exit(0); 529 } 530 531 /* make a clean exit on interrupts */ 532 void 533 cleanup(int signo) 534 { 535 struct pcap_stat stat; 536 sigset_t allsigs; 537 538 sigfillset(&allsigs); 539 sigprocmask(SIG_BLOCK, &allsigs, NULL); 540 541 /* Can't print the summary if reading from a savefile */ 542 dprintf(STDERR_FILENO, "\n"); 543 if (pd != NULL && pcap_file(pd) == NULL) { 544 if (priv_pcap_stats(&stat) < 0) { 545 dprintf(STDERR_FILENO, 546 "pcap_stats: %s\n", pcap_geterr(pd)); 547 } else { 548 dprintf(STDERR_FILENO, 549 "%u packets received by filter\n", stat.ps_recv); 550 dprintf(STDERR_FILENO, 551 "%u packets dropped by kernel\n", stat.ps_drop); 552 } 553 } 554 _exit(0); 555 } 556 557 void 558 gotchld(int signo) 559 { 560 pid_t pid; 561 int status; 562 int save_err = errno; 563 564 do { 565 pid = waitpid(child_pid, &status, WNOHANG); 566 if (pid > 0 && (WIFEXITED(status) || WIFSIGNALED(status))) 567 cleanup(0); 568 } while (pid == -1 && errno == EINTR); 569 570 if (pid == -1) 571 _exit(1); 572 573 errno = save_err; 574 } 575 576 /* dump the buffer in `emacs-hexl' style */ 577 void 578 default_print_hexl(const u_char *cp, unsigned int length) 579 { 580 unsigned int i, j, jm; 581 int c; 582 char ln[128], buf[128]; 583 584 printf("\n"); 585 for (i = 0; i < length; i += 0x10) { 586 snprintf(ln, sizeof(ln), " %04x: ", (unsigned int)i); 587 jm = length - i; 588 jm = jm > 16 ? 16 : jm; 589 590 for (j = 0; j < jm; j++) { 591 if ((j % 2) == 1) 592 snprintf(buf, sizeof(buf), "%02x ", 593 (unsigned int)cp[i+j]); 594 else 595 snprintf(buf, sizeof(buf), "%02x", 596 (unsigned int)cp[i+j]); 597 strlcat(ln, buf, sizeof ln); 598 } 599 for (; j < 16; j++) { 600 if ((j % 2) == 1) 601 snprintf(buf, sizeof buf, " "); 602 else 603 snprintf(buf, sizeof buf, " "); 604 strlcat(ln, buf, sizeof ln); 605 } 606 607 strlcat(ln, " ", sizeof ln); 608 for (j = 0; j < jm; j++) { 609 c = cp[i+j]; 610 c = isprint(c) ? c : '.'; 611 buf[0] = c; 612 buf[1] = '\0'; 613 strlcat(ln, buf, sizeof ln); 614 } 615 printf("%s\n", ln); 616 } 617 } 618 619 /* dump the text from the buffer */ 620 void 621 default_print_ascii(const u_char *cp, unsigned int length) 622 { 623 int c, i; 624 625 printf("\n"); 626 for (i = 0; i < length; i++) { 627 c = cp[i]; 628 if (isprint(c) || c == '\t' || c == '\n' || c == '\r') 629 putchar(c); 630 else 631 putchar('.'); 632 } 633 } 634 635 /* Like default_print() but data need not be aligned */ 636 void 637 default_print_unaligned(const u_char *cp, u_int length) 638 { 639 u_int i, s; 640 int nshorts; 641 642 if (Xflag) { 643 /* dump the buffer in `emacs-hexl' style */ 644 default_print_hexl(cp, length); 645 } else if (Aflag) { 646 /* dump the text in the buffer */ 647 default_print_ascii(cp, length); 648 } else { 649 /* dump the buffer in old tcpdump style */ 650 nshorts = (u_int) length / sizeof(u_short); 651 i = 0; 652 while (--nshorts >= 0) { 653 if ((i++ % 8) == 0) 654 printf("\n\t\t\t"); 655 s = *cp++; 656 printf(" %02x%02x", s, *cp++); 657 } 658 if (length & 1) { 659 if ((i % 8) == 0) 660 printf("\n\t\t\t"); 661 printf(" %02x", *cp); 662 } 663 } 664 } 665 666 void 667 default_print(const u_char *bp, u_int length) 668 { 669 const u_short *sp; 670 u_int i; 671 int nshorts; 672 673 if (Xflag) { 674 /* dump the buffer in `emacs-hexl' style */ 675 default_print_hexl(bp, length); 676 } else if (Aflag) { 677 /* dump the text in the buffer */ 678 default_print_ascii(bp, length); 679 } else { 680 /* dump the buffer in old tcpdump style */ 681 if ((long)bp & 1) { 682 default_print_unaligned(bp, length); 683 return; 684 } 685 sp = (u_short *)bp; 686 nshorts = (u_int) length / sizeof(u_short); 687 i = 0; 688 while (--nshorts >= 0) { 689 if ((i++ % 8) == 0) 690 printf("\n\t\t\t"); 691 printf(" %04x", ntohs(*sp++)); 692 } 693 if (length & 1) { 694 if ((i % 8) == 0) 695 printf("\n\t\t\t"); 696 printf(" %02x", *(u_char *)sp); 697 } 698 } 699 } 700 701 void 702 set_slave_signals(void) 703 { 704 setsignal(SIGTERM, cleanup); 705 setsignal(SIGINT, cleanup); 706 setsignal(SIGCHLD, gotchld); 707 setsignal(SIGHUP, cleanup); 708 } 709 710 __dead void 711 usage(void) 712 { 713 (void)fprintf(stderr, 714 "Usage: %s [-AadefILlNnOopqStvXx] [-B fildrop] [-c count] [-D direction]\n", 715 program_name); 716 (void)fprintf(stderr, 717 "\t [-E [espalg:]espkey] [-F file] [-i interface] [-r file]\n"); 718 (void)fprintf(stderr, 719 "\t [-s snaplen] [-T type] [-w file] [-y datalinktype] [expression]\n"); 720 exit(1); 721 } 722