1 /* $OpenBSD: tcpdump.c,v 1.83 2018/02/06 03:07:51 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 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 { ppp_hdlc_if_print, DLT_PPP_SERIAL }, 119 { fddi_if_print, DLT_FDDI }, 120 { null_if_print, DLT_NULL }, 121 { raw_if_print, DLT_RAW }, 122 { atm_if_print, DLT_ATM_RFC1483 }, 123 { loop_if_print, DLT_LOOP }, 124 { enc_if_print, DLT_ENC }, 125 { pflog_if_print, DLT_PFLOG }, 126 { pfsync_if_print, DLT_PFSYNC }, 127 { ppp_ether_if_print, DLT_PPP_ETHER }, 128 { ieee802_11_if_print, DLT_IEEE802_11 }, 129 { ieee802_11_radio_if_print, DLT_IEEE802_11_RADIO }, 130 { ofp_if_print, DLT_OPENFLOW }, 131 { usbpcap_if_print, DLT_USBPCAP }, 132 { NULL, 0 }, 133 }; 134 135 static pcap_handler 136 lookup_printer(int type) 137 { 138 struct printer *p; 139 140 for (p = printers; p->f; ++p) { 141 if (type == p->type) 142 return p->f; 143 } 144 145 error("unknown data link type 0x%x", type); 146 /* NOTREACHED */ 147 } 148 149 static int 150 init_pfosfp(void) 151 { 152 pf_osfp_initialize(); 153 if (pfctl_file_fingerprints(-1, 154 PF_OPT_QUIET|PF_OPT_NOACTION, PF_OSFP_FILE) == 0) 155 return 1; 156 return 0; 157 } 158 159 static pcap_t *pd; 160 161 /* Multiple DLT support */ 162 void pcap_list_linktypes(pcap_t *); 163 void pcap_print_linktype(u_int); 164 165 void 166 pcap_print_linktype(u_int dlt) 167 { 168 const char *name; 169 170 if ((name = pcap_datalink_val_to_name(dlt)) != NULL) 171 fprintf(stderr, "%s\n", name); 172 else 173 fprintf(stderr, "<unknown: %u>\n", dlt); 174 } 175 176 void 177 pcap_list_linktypes(pcap_t *p) 178 { 179 int fd = p->fd; 180 u_int n; 181 182 #define MAXDLT 100 183 184 u_int dltlist[MAXDLT]; 185 struct bpf_dltlist dl = {MAXDLT, dltlist}; 186 187 if (fd < 0) 188 error("Invalid bpf descriptor"); 189 190 if (ioctl(fd, BIOCGDLTLIST, &dl) < 0) 191 err(1, "BIOCGDLTLIST"); 192 193 if (dl.bfl_len > MAXDLT) 194 error("Invalid number of linktypes: %u", dl.bfl_len); 195 196 fprintf(stderr, "%d link type%s supported:\n", dl.bfl_len, 197 dl.bfl_len == 1 ? "" : "s"); 198 199 for (n = 0; n < dl.bfl_len; n++) { 200 fprintf(stderr, "\t"); 201 pcap_print_linktype(dltlist[n]); 202 } 203 } 204 205 int 206 main(int argc, char **argv) 207 { 208 int cnt = -1, op, i; 209 bpf_u_int32 localnet, netmask; 210 char *cp, *infile = NULL, *RFileName = NULL; 211 char ebuf[PCAP_ERRBUF_SIZE], *WFileName = NULL; 212 pcap_handler printer; 213 struct bpf_program *fcode; 214 u_char *pcap_userdata; 215 u_int dirfilt = 0, dlt = (u_int) -1; 216 const char *errstr; 217 218 if ((cp = strrchr(argv[0], '/')) != NULL) 219 program_name = cp + 1; 220 else 221 program_name = argv[0]; 222 223 /* '-P' used internally, exec privileged portion */ 224 if (argc >= 2 && strcmp("-P", argv[1]) == 0) 225 priv_exec(argc, argv); 226 227 if (priv_init(argc, argv)) 228 error("Failed to setup privsep"); 229 230 /* state: STATE_INIT */ 231 232 opterr = 0; 233 while ((op = getopt(argc, argv, 234 "Aac:D:deE:fF:i:IlLnNOopqr:s:StT:vw:xXy:Y")) != -1) 235 switch (op) { 236 237 case 'A': 238 xflag = 1; 239 Aflag = 1; 240 break; 241 242 case 'a': 243 aflag = 1; 244 break; 245 246 case 'c': 247 cnt = strtonum(optarg, 1, INT_MAX, &errstr); 248 if (errstr) 249 error("invalid packet count %s: %s", 250 optarg, errstr); 251 break; 252 253 case 'D': 254 if (strcasecmp(optarg, "in") == 0) 255 dirfilt = BPF_DIRECTION_OUT; 256 else if (strcasecmp(optarg, "out") == 0) 257 dirfilt = BPF_DIRECTION_IN; 258 else 259 error("invalid traffic direction %s", optarg); 260 break; 261 262 case 'd': 263 ++dflag; 264 break; 265 case 'e': 266 eflag = 1; 267 break; 268 269 case 'f': 270 fflag = 1; 271 break; 272 273 case 'F': 274 infile = optarg; 275 break; 276 277 case 'i': 278 device = optarg; 279 break; 280 281 case 'I': 282 Iflag = 1; 283 break; 284 285 case 'l': 286 setvbuf(stdout, NULL, _IOLBF, 0); 287 break; 288 case 'L': 289 Lflag = 1; 290 break; 291 case 'n': 292 nflag = 1; 293 break; 294 295 case 'N': 296 Nflag = 1; 297 break; 298 299 case 'O': 300 Oflag = 0; 301 break; 302 303 case 'o': 304 oflag = 1; 305 break; 306 307 case 'p': 308 pflag = 1; 309 break; 310 311 case 'q': 312 qflag = 1; 313 break; 314 315 case 'r': 316 RFileName = optarg; 317 break; 318 319 case 's': 320 snaplen = strtonum(optarg, 1, INT_MAX, &errstr); 321 if (errstr) 322 error("invalid snaplen %s: %s", optarg, errstr); 323 break; 324 325 case 'S': 326 Sflag = 1; 327 break; 328 329 case 't': 330 --tflag; 331 break; 332 333 case 'T': 334 if (strcasecmp(optarg, "vat") == 0) 335 packettype = PT_VAT; 336 else if (strcasecmp(optarg, "wb") == 0) 337 packettype = PT_WB; 338 else if (strcasecmp(optarg, "rpc") == 0) 339 packettype = PT_RPC; 340 else if (strcasecmp(optarg, "rtp") == 0) 341 packettype = PT_RTP; 342 else if (strcasecmp(optarg, "rtcp") == 0) 343 packettype = PT_RTCP; 344 else if (strcasecmp(optarg, "cnfp") == 0) 345 packettype = PT_CNFP; 346 else if (strcasecmp(optarg, "vrrp") == 0) 347 packettype = PT_VRRP; 348 else if (strcasecmp(optarg, "tcp") == 0) 349 packettype = PT_TCP; 350 else if (strcasecmp(optarg, "sack") == 0) 351 /* 352 * kept for compatibility; DEFAULT_SNAPLEN 353 * used to be too short to capture SACK. 354 */ 355 ; 356 else 357 error("unknown packet type `%s'", optarg); 358 break; 359 360 case 'v': 361 ++vflag; 362 break; 363 364 case 'w': 365 WFileName = optarg; 366 break; 367 #ifdef YYDEBUG 368 case 'Y': 369 { 370 /* Undocumented flag */ 371 extern int yydebug; 372 yydebug = 1; 373 } 374 break; 375 #endif 376 case 'y': 377 i = pcap_datalink_name_to_val(optarg); 378 if (i < 0) 379 error("invalid data link type: %s", optarg); 380 dlt = (u_int)i; 381 break; 382 383 case 'x': 384 xflag = 1; 385 break; 386 387 case 'X': 388 Xflag = 1; 389 xflag = 1; 390 break; 391 392 case 'E': 393 if (esp_init(optarg) < 0) 394 error("bad esp specification `%s'", optarg); 395 break; 396 397 default: 398 usage(); 399 /* NOTREACHED */ 400 } 401 402 if (snaplen == 0) { 403 switch (dlt) { 404 case DLT_IEEE802_11: 405 snaplen = IEEE802_11_SNAPLEN; 406 break; 407 case DLT_IEEE802_11_RADIO: 408 snaplen = IEEE802_11_RADIO_SNAPLEN; 409 break; 410 default: 411 snaplen = DEFAULT_SNAPLEN; 412 break; 413 } 414 } 415 416 if (aflag && nflag) 417 error("-a and -n options are incompatible"); 418 419 if (RFileName != NULL) { 420 pd = priv_pcap_offline(RFileName, ebuf); 421 if (pd == NULL) 422 error("%s", ebuf); 423 /* state: STATE_BPF */ 424 localnet = 0; 425 netmask = 0; 426 if (fflag != 0) 427 error("-f and -r options are incompatible"); 428 } else { 429 if (device == NULL) { 430 device = pcap_lookupdev(ebuf); 431 if (device == NULL) 432 error("%s", ebuf); 433 } 434 pd = priv_pcap_live(device, snaplen, !pflag, 1000, ebuf, 435 dlt, dirfilt); 436 if (pd == NULL) 437 error("%s", ebuf); 438 439 /* state: STATE_BPF */ 440 if (pcap_lookupnet(device, &localnet, &netmask, ebuf)) { 441 if (fflag) 442 warning("%s", ebuf); 443 localnet = 0; 444 netmask = 0; 445 } 446 } 447 i = pcap_snapshot(pd); 448 if (snaplen < i) { 449 warning("snaplen raised from %d to %d", snaplen, i); 450 snaplen = i; 451 } 452 453 if (Lflag) { 454 pcap_list_linktypes(pd); 455 exit(0); 456 } 457 458 fcode = priv_pcap_setfilter(pd, Oflag, netmask); 459 /* state: STATE_FILTER */ 460 if (fcode == NULL) 461 error("%s", pcap_geterr(pd)); 462 if (dflag) { 463 bpf_dump(fcode, dflag); 464 exit(0); 465 } 466 init_addrtoname(localnet, netmask); 467 468 if (WFileName) { 469 pcap_dumper_t *p; 470 471 p = priv_pcap_dump_open(pd, WFileName); 472 /* state: STATE_RUN */ 473 if (p == NULL) 474 error("%s", pcap_geterr(pd)); 475 { 476 FILE *fp = (FILE *)p; /* XXX touching pcap guts! */ 477 fflush(fp); 478 setvbuf(fp, NULL, _IONBF, 0); 479 } 480 printer = pcap_dump; 481 pcap_userdata = (u_char *)p; 482 } else { 483 printer = lookup_printer(pcap_datalink(pd)); 484 pcap_userdata = NULL; 485 priv_init_done(); 486 /* state: STATE_RUN */ 487 } 488 if (RFileName == NULL) { 489 (void)fprintf(stderr, "%s: listening on %s, link-type ", 490 program_name, device); 491 pcap_print_linktype(pd->linktype); 492 (void)fflush(stderr); 493 } 494 495 if (oflag) 496 oflag = init_pfosfp(); 497 if (tflag > 0) 498 thiszone = gmt2local(0); 499 500 if (pledge("stdio", NULL) == -1) 501 err(1, "pledge"); 502 503 if (pcap_loop(pd, cnt, printer, pcap_userdata) < 0) { 504 (void)fprintf(stderr, "%s: pcap_loop: %s\n", 505 program_name, pcap_geterr(pd)); 506 exit(1); 507 } 508 pcap_close(pd); 509 exit(0); 510 } 511 512 /* make a clean exit on interrupts */ 513 void 514 cleanup(int signo) 515 { 516 struct pcap_stat stat; 517 sigset_t allsigs; 518 519 sigfillset(&allsigs); 520 sigprocmask(SIG_BLOCK, &allsigs, NULL); 521 522 /* Can't print the summary if reading from a savefile */ 523 dprintf(STDERR_FILENO, "\n"); 524 if (pd != NULL && pcap_file(pd) == NULL) { 525 if (priv_pcap_stats(&stat) < 0) { 526 dprintf(STDERR_FILENO, 527 "pcap_stats: %s\n", pcap_geterr(pd)); 528 } else { 529 dprintf(STDERR_FILENO, 530 "%u packets received by filter\n", stat.ps_recv); 531 dprintf(STDERR_FILENO, 532 "%u packets dropped by kernel\n", stat.ps_drop); 533 } 534 } 535 _exit(0); 536 } 537 538 void 539 gotchld(int signo) 540 { 541 pid_t pid; 542 int status; 543 int save_err = errno; 544 545 do { 546 pid = waitpid(child_pid, &status, WNOHANG); 547 if (pid > 0 && (WIFEXITED(status) || WIFSIGNALED(status))) 548 cleanup(0); 549 } while (pid == -1 && errno == EINTR); 550 551 if (pid == -1) 552 _exit(1); 553 554 errno = save_err; 555 } 556 557 /* dump the buffer in `emacs-hexl' style */ 558 void 559 default_print_hexl(const u_char *cp, unsigned int length) 560 { 561 unsigned int i, j, jm; 562 int c; 563 char ln[128], buf[128]; 564 565 printf("\n"); 566 for (i = 0; i < length; i += 0x10) { 567 snprintf(ln, sizeof(ln), " %04x: ", (unsigned int)i); 568 jm = length - i; 569 jm = jm > 16 ? 16 : jm; 570 571 for (j = 0; j < jm; j++) { 572 if ((j % 2) == 1) 573 snprintf(buf, sizeof(buf), "%02x ", 574 (unsigned int)cp[i+j]); 575 else 576 snprintf(buf, sizeof(buf), "%02x", 577 (unsigned int)cp[i+j]); 578 strlcat(ln, buf, sizeof ln); 579 } 580 for (; j < 16; j++) { 581 if ((j % 2) == 1) 582 snprintf(buf, sizeof buf, " "); 583 else 584 snprintf(buf, sizeof buf, " "); 585 strlcat(ln, buf, sizeof ln); 586 } 587 588 strlcat(ln, " ", sizeof ln); 589 for (j = 0; j < jm; j++) { 590 c = cp[i+j]; 591 c = isprint(c) ? c : '.'; 592 buf[0] = c; 593 buf[1] = '\0'; 594 strlcat(ln, buf, sizeof ln); 595 } 596 printf("%s\n", ln); 597 } 598 } 599 600 /* dump the text from the buffer */ 601 void 602 default_print_ascii(const u_char *cp, unsigned int length) 603 { 604 int c, i; 605 606 printf("\n"); 607 for (i = 0; i < length; i++) { 608 c = cp[i]; 609 if (isprint(c) || c == '\t' || c == '\n' || c == '\r') 610 putchar(c); 611 else 612 putchar('.'); 613 } 614 } 615 616 /* Like default_print() but data need not be aligned */ 617 void 618 default_print_unaligned(const u_char *cp, u_int length) 619 { 620 u_int i, s; 621 int nshorts; 622 623 if (Xflag) { 624 /* dump the buffer in `emacs-hexl' style */ 625 default_print_hexl(cp, length); 626 } else if (Aflag) { 627 /* dump the text in the buffer */ 628 default_print_ascii(cp, length); 629 } else { 630 /* dump the buffer in old tcpdump style */ 631 nshorts = (u_int) length / sizeof(u_short); 632 i = 0; 633 while (--nshorts >= 0) { 634 if ((i++ % 8) == 0) 635 (void)printf("\n\t\t\t"); 636 s = *cp++; 637 (void)printf(" %02x%02x", s, *cp++); 638 } 639 if (length & 1) { 640 if ((i % 8) == 0) 641 (void)printf("\n\t\t\t"); 642 (void)printf(" %02x", *cp); 643 } 644 } 645 } 646 647 void 648 default_print(const u_char *bp, u_int length) 649 { 650 const u_short *sp; 651 u_int i; 652 int nshorts; 653 654 if (Xflag) { 655 /* dump the buffer in `emacs-hexl' style */ 656 default_print_hexl(bp, length); 657 } else if (Aflag) { 658 /* dump the text in the buffer */ 659 default_print_ascii(bp, length); 660 } else { 661 /* dump the buffer in old tcpdump style */ 662 if ((long)bp & 1) { 663 default_print_unaligned(bp, length); 664 return; 665 } 666 sp = (u_short *)bp; 667 nshorts = (u_int) length / sizeof(u_short); 668 i = 0; 669 while (--nshorts >= 0) { 670 if ((i++ % 8) == 0) 671 (void)printf("\n\t\t\t"); 672 (void)printf(" %04x", ntohs(*sp++)); 673 } 674 if (length & 1) { 675 if ((i % 8) == 0) 676 (void)printf("\n\t\t\t"); 677 (void)printf(" %02x", *(u_char *)sp); 678 } 679 } 680 } 681 682 void 683 set_slave_signals(void) 684 { 685 setsignal(SIGTERM, cleanup); 686 setsignal(SIGINT, cleanup); 687 setsignal(SIGCHLD, gotchld); 688 setsignal(SIGHUP, cleanup); 689 } 690 691 __dead void 692 usage(void) 693 { 694 (void)fprintf(stderr, 695 "Usage: %s [-AadefILlNnOopqStvXx] [-c count] [-D direction]\n", 696 program_name); 697 (void)fprintf(stderr, 698 "\t [-E [espalg:]espkey] [-F file] [-i interface] [-r file]\n"); 699 (void)fprintf(stderr, 700 "\t [-s snaplen] [-T type] [-w file] [-y datalinktype] [expression]\n"); 701 exit(1); 702 } 703