/* $OpenBSD: tcpdump.c,v 1.95 2020/12/04 11:36:13 mvs Exp $ */ /* * Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that: (1) source code distributions * retain the above copyright notice and this paragraph in its entirety, (2) * distributions including binary code include the above copyright notice and * this paragraph in its entirety in the documentation or other materials * provided with the distribution, and (3) all advertising materials mentioning * features or use of this software display the following acknowledgement: * ``This product includes software developed by the University of California, * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of * the University nor the names of its contributors may be used to endorse * or promote products derived from this software without specific prior * written permission. * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. */ /* * tcpdump - monitor tcp/ip traffic on an ethernet. * * First written in 1987 by Van Jacobson, Lawrence Berkeley Laboratory. * Mercilessly hacked and occasionally improved since then via the * combined efforts of Van, Steve McCanne and Craig Leres of LBL. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "interface.h" #include "addrtoname.h" #include "setsignal.h" #include "gmt2local.h" #include #include #include #include "pfctl.h" #include "pfctl_parser.h" #include "privsep.h" int Aflag; /* dump ascii */ int aflag; /* translate network and broadcast addresses */ int Bflag; /* BPF fildrop setting */ int dflag; /* print filter code */ int eflag; /* print ethernet header */ int fflag; /* don't translate "foreign" IP address */ int Iflag; /* include interface in output */ int Lflag; /* List available link types */ int nflag; /* leave addresses as numbers */ int Nflag; /* remove domains from printed host names */ int Oflag = 1; /* run filter code optimizer */ int oflag; /* print passive OS fingerprints */ int pflag; /* don't go promiscuous */ int qflag; /* quick (shorter) output */ int Sflag; /* print raw TCP sequence numbers */ int tflag = 1; /* print packet arrival time */ int vflag; /* verbose */ int xflag; /* print packet in hex */ int Xflag; /* print packet in emacs-hexl style */ int packettype; char *program_name; char *device = NULL; int32_t thiszone; /* seconds offset from gmt to local time */ extern volatile pid_t child_pid; /* Externs */ extern void bpf_dump(struct bpf_program *, int); extern int esp_init(char *); /* Forwards */ void cleanup(int); void gotchld(int); extern __dead void usage(void); /* Length of saved portion of packet. */ int snaplen = 0; struct printer { pcap_handler f; int type; }; /* XXX needed if using old bpf.h */ #ifndef DLT_ATM_RFC1483 #define DLT_ATM_RFC1483 11 #endif static struct printer printers[] = { { ether_if_print, DLT_EN10MB }, { ether_if_print, DLT_IEEE802 }, { sl_if_print, DLT_SLIP }, { sl_bsdos_if_print, DLT_SLIP_BSDOS }, { ppp_if_print, DLT_PPP }, { ppp_hdlc_if_print, DLT_PPP_SERIAL }, { fddi_if_print, DLT_FDDI }, { null_if_print, DLT_NULL }, { raw_if_print, DLT_RAW }, { atm_if_print, DLT_ATM_RFC1483 }, { loop_if_print, DLT_LOOP }, { enc_if_print, DLT_ENC }, { pflog_if_print, DLT_PFLOG }, { pfsync_if_print, DLT_PFSYNC }, { ppp_ether_if_print, DLT_PPP_ETHER }, { ieee802_11_if_print, DLT_IEEE802_11 }, { ieee802_11_radio_if_print, DLT_IEEE802_11_RADIO }, { ofp_if_print, DLT_OPENFLOW }, { usbpcap_if_print, DLT_USBPCAP }, { NULL, 0 }, }; static pcap_handler lookup_printer(int type) { struct printer *p; for (p = printers; p->f; ++p) { if (type == p->type) return p->f; } error("unknown data link type 0x%x", type); /* NOTREACHED */ } static int init_pfosfp(void) { pf_osfp_initialize(); if (pfctl_file_fingerprints(-1, PF_OPT_QUIET|PF_OPT_NOACTION, PF_OSFP_FILE) == 0) return 1; return 0; } static pcap_t *pd; /* Multiple DLT support */ void pcap_list_linktypes(pcap_t *); void pcap_print_linktype(u_int); void pcap_print_linktype(u_int dlt) { const char *name; if ((name = pcap_datalink_val_to_name(dlt)) != NULL) fprintf(stderr, "%s\n", name); else fprintf(stderr, "\n", dlt); } void pcap_list_linktypes(pcap_t *p) { int fd = p->fd; u_int n; #define MAXDLT 100 u_int dltlist[MAXDLT]; struct bpf_dltlist dl = {MAXDLT, dltlist}; if (fd < 0) error("Invalid bpf descriptor"); if (ioctl(fd, BIOCGDLTLIST, &dl) == -1) err(1, "BIOCGDLTLIST"); if (dl.bfl_len > MAXDLT) error("Invalid number of linktypes: %u", dl.bfl_len); fprintf(stderr, "%d link type%s supported:\n", dl.bfl_len, dl.bfl_len == 1 ? "" : "s"); for (n = 0; n < dl.bfl_len; n++) { fprintf(stderr, "\t"); pcap_print_linktype(dltlist[n]); } } int main(int argc, char **argv) { int cnt = -1, op, i; bpf_u_int32 localnet, netmask; char *cp, *infile = NULL, *RFileName = NULL; char ebuf[PCAP_ERRBUF_SIZE], *WFileName = NULL; pcap_handler printer; struct bpf_program *fcode; u_char *pcap_userdata; u_int dirfilt = 0, dlt = (u_int) -1; const char *errstr; if ((cp = strrchr(argv[0], '/')) != NULL) program_name = cp + 1; else program_name = argv[0]; /* '-P' used internally, exec privileged portion */ if (argc >= 2 && strcmp("-P", argv[1]) == 0) priv_exec(argc, argv); if (priv_init(argc, argv)) error("Failed to setup privsep"); /* state: STATE_INIT */ opterr = 0; while ((op = getopt(argc, argv, "AaB:c:D:deE:fF:i:IlLnNOopqr:s:StT:vw:xXy:")) != -1) switch (op) { case 'A': xflag = 1; Aflag = 1; break; case 'a': aflag = 1; break; case 'B': if (strcasecmp(optarg, "pass") == 0) Bflag = BPF_FILDROP_PASS; else if (strcasecmp(optarg, "capture") == 0) Bflag = BPF_FILDROP_CAPTURE; else if (strcasecmp(optarg, "drop") == 0) Bflag = BPF_FILDROP_DROP; else { error("invalid BPF fildrop option: %s", optarg); } break; case 'c': cnt = strtonum(optarg, 1, INT_MAX, &errstr); if (errstr) error("invalid packet count %s: %s", optarg, errstr); break; case 'D': if (strcasecmp(optarg, "in") == 0) dirfilt = BPF_DIRECTION_OUT; else if (strcasecmp(optarg, "out") == 0) dirfilt = BPF_DIRECTION_IN; else error("invalid traffic direction %s", optarg); break; case 'd': ++dflag; break; case 'e': eflag = 1; break; case 'f': fflag = 1; break; case 'F': infile = optarg; break; case 'i': device = optarg; break; case 'I': Iflag = 1; break; case 'l': setvbuf(stdout, NULL, _IOLBF, 0); break; case 'L': Lflag = 1; break; case 'n': nflag = 1; break; case 'N': Nflag = 1; break; case 'O': Oflag = 0; break; case 'o': oflag = 1; break; case 'p': pflag = 1; break; case 'q': qflag = 1; break; case 'r': RFileName = optarg; break; case 's': snaplen = strtonum(optarg, 1, INT_MAX, &errstr); if (errstr) error("invalid snaplen %s: %s", optarg, errstr); break; case 'S': Sflag = 1; break; case 't': --tflag; break; case 'T': if (strcasecmp(optarg, "vat") == 0) packettype = PT_VAT; else if (strcasecmp(optarg, "wb") == 0) packettype = PT_WB; else if (strcasecmp(optarg, "rpc") == 0) packettype = PT_RPC; else if (strcasecmp(optarg, "rtp") == 0) packettype = PT_RTP; else if (strcasecmp(optarg, "rtcp") == 0) packettype = PT_RTCP; else if (strcasecmp(optarg, "cnfp") == 0) packettype = PT_CNFP; else if (strcasecmp(optarg, "vrrp") == 0) packettype = PT_VRRP; else if (strcasecmp(optarg, "tcp") == 0) packettype = PT_TCP; else if (strcasecmp(optarg, "gre") == 0) packettype = PT_GRE; else if (strcasecmp(optarg, "vxlan") == 0) packettype = PT_VXLAN; else if (strcasecmp(optarg, "geneve") == 0) packettype = PT_GENEVE; else if (strcasecmp(optarg, "erspan") == 0) packettype = PT_ERSPAN; else if (strcasecmp(optarg, "mpls") == 0) packettype = PT_MPLS; else if (strcasecmp(optarg, "tftp") == 0) packettype = PT_TFTP; else if (strcasecmp(optarg, "wg") == 0) packettype = PT_WIREGUARD; else if (strcasecmp(optarg, "sack") == 0) /* * kept for compatibility; DEFAULT_SNAPLEN * used to be too short to capture SACK. */ ; else error("unknown packet type `%s'", optarg); break; case 'v': ++vflag; break; case 'w': WFileName = optarg; break; case 'y': i = pcap_datalink_name_to_val(optarg); if (i < 0) error("invalid data link type: %s", optarg); dlt = (u_int)i; break; case 'x': xflag = 1; break; case 'X': Xflag = 1; xflag = 1; break; case 'E': if (esp_init(optarg) < 0) error("bad esp specification `%s'", optarg); break; default: usage(); /* NOTREACHED */ } if (snaplen == 0) { switch (dlt) { case DLT_IEEE802_11: snaplen = IEEE802_11_SNAPLEN; break; case DLT_IEEE802_11_RADIO: snaplen = IEEE802_11_RADIO_SNAPLEN; break; default: snaplen = DEFAULT_SNAPLEN; break; } } if (aflag && nflag) error("-a and -n options are incompatible"); if (RFileName != NULL) { pd = priv_pcap_offline(RFileName, ebuf); if (pd == NULL) error("%s", ebuf); /* state: STATE_BPF */ localnet = 0; netmask = 0; if (fflag != 0) error("-f and -r options are incompatible"); } else { if (device == NULL) { device = pcap_lookupdev(ebuf); if (device == NULL) error("%s", ebuf); } pd = priv_pcap_live(device, snaplen, !pflag, 1000, ebuf, dlt, dirfilt, Bflag); if (pd == NULL) error("%s", ebuf); /* state: STATE_BPF */ if (pcap_lookupnet(device, &localnet, &netmask, ebuf)) { if (fflag) warning("%s", ebuf); localnet = 0; netmask = 0; } } i = pcap_snapshot(pd); if (snaplen < i) { warning("snaplen raised from %d to %d", snaplen, i); snaplen = i; } if (Lflag) { pcap_list_linktypes(pd); exit(0); } fcode = priv_pcap_setfilter(pd, Oflag, netmask); /* state: STATE_FILTER */ if (fcode == NULL) error("%s", pcap_geterr(pd)); if (dflag) { bpf_dump(fcode, dflag); exit(0); } if (oflag) oflag = init_pfosfp(); init_addrtoname(localnet, netmask); if (WFileName) { pcap_dumper_t *p; p = priv_pcap_dump_open(pd, WFileName); /* state: STATE_RUN */ if (p == NULL) error("%s", pcap_geterr(pd)); { FILE *fp = (FILE *)p; /* XXX touching pcap guts! */ fflush(fp); setvbuf(fp, NULL, _IONBF, 0); } printer = pcap_dump; pcap_userdata = (u_char *)p; } else { printer = lookup_printer(pcap_datalink(pd)); pcap_userdata = NULL; priv_init_done(); /* state: STATE_RUN */ } if (RFileName == NULL) { (void)fprintf(stderr, "%s: listening on %s, link-type ", program_name, device); pcap_print_linktype(pd->linktype); (void)fflush(stderr); } if (tflag > 0) thiszone = gmt2local(0); if (pledge("stdio", NULL) == -1) err(1, "pledge"); if (pcap_loop(pd, cnt, printer, pcap_userdata) < 0) { (void)fprintf(stderr, "%s: pcap_loop: %s\n", program_name, pcap_geterr(pd)); exit(1); } pcap_close(pd); exit(0); } /* make a clean exit on interrupts */ void cleanup(int signo) { struct pcap_stat stat; sigset_t allsigs; sigfillset(&allsigs); sigprocmask(SIG_BLOCK, &allsigs, NULL); /* Can't print the summary if reading from a savefile */ dprintf(STDERR_FILENO, "\n"); if (pd != NULL && pcap_file(pd) == NULL) { if (priv_pcap_stats(&stat) < 0) { dprintf(STDERR_FILENO, "pcap_stats: %s\n", pcap_geterr(pd)); } else { dprintf(STDERR_FILENO, "%u packets received by filter\n", stat.ps_recv); dprintf(STDERR_FILENO, "%u packets dropped by kernel\n", stat.ps_drop); } } _exit(0); } void gotchld(int signo) { pid_t pid; int status; int save_err = errno; do { pid = waitpid(child_pid, &status, WNOHANG); if (pid > 0 && (WIFEXITED(status) || WIFSIGNALED(status))) cleanup(0); } while (pid == -1 && errno == EINTR); if (pid == -1) _exit(1); errno = save_err; } /* dump the buffer in `emacs-hexl' style */ void default_print_hexl(const u_char *cp, unsigned int length) { unsigned int i, j, jm; int c; char ln[128], buf[128]; printf("\n"); for (i = 0; i < length; i += 0x10) { snprintf(ln, sizeof(ln), " %04x: ", (unsigned int)i); jm = length - i; jm = jm > 16 ? 16 : jm; for (j = 0; j < jm; j++) { if ((j % 2) == 1) snprintf(buf, sizeof(buf), "%02x ", (unsigned int)cp[i+j]); else snprintf(buf, sizeof(buf), "%02x", (unsigned int)cp[i+j]); strlcat(ln, buf, sizeof ln); } for (; j < 16; j++) { if ((j % 2) == 1) snprintf(buf, sizeof buf, " "); else snprintf(buf, sizeof buf, " "); strlcat(ln, buf, sizeof ln); } strlcat(ln, " ", sizeof ln); for (j = 0; j < jm; j++) { c = cp[i+j]; c = isprint(c) ? c : '.'; buf[0] = c; buf[1] = '\0'; strlcat(ln, buf, sizeof ln); } printf("%s\n", ln); } } /* dump the text from the buffer */ void default_print_ascii(const u_char *cp, unsigned int length) { int c, i; printf("\n"); for (i = 0; i < length; i++) { c = cp[i]; if (isprint(c) || c == '\t' || c == '\n' || c == '\r') putchar(c); else putchar('.'); } } /* Like default_print() but data need not be aligned */ void default_print_unaligned(const u_char *cp, u_int length) { u_int i, s; int nshorts; if (Xflag) { /* dump the buffer in `emacs-hexl' style */ default_print_hexl(cp, length); } else if (Aflag) { /* dump the text in the buffer */ default_print_ascii(cp, length); } else { /* dump the buffer in old tcpdump style */ nshorts = (u_int) length / sizeof(u_short); i = 0; while (--nshorts >= 0) { if ((i++ % 8) == 0) printf("\n\t\t\t"); s = *cp++; printf(" %02x%02x", s, *cp++); } if (length & 1) { if ((i % 8) == 0) printf("\n\t\t\t"); printf(" %02x", *cp); } } } void default_print(const u_char *bp, u_int length) { const u_short *sp; u_int i; int nshorts; if (Xflag) { /* dump the buffer in `emacs-hexl' style */ default_print_hexl(bp, length); } else if (Aflag) { /* dump the text in the buffer */ default_print_ascii(bp, length); } else { /* dump the buffer in old tcpdump style */ if ((long)bp & 1) { default_print_unaligned(bp, length); return; } sp = (u_short *)bp; nshorts = (u_int) length / sizeof(u_short); i = 0; while (--nshorts >= 0) { if ((i++ % 8) == 0) printf("\n\t\t\t"); printf(" %04x", ntohs(*sp++)); } if (length & 1) { if ((i % 8) == 0) printf("\n\t\t\t"); printf(" %02x", *(u_char *)sp); } } } void set_slave_signals(void) { setsignal(SIGTERM, cleanup); setsignal(SIGINT, cleanup); setsignal(SIGCHLD, gotchld); setsignal(SIGHUP, cleanup); } __dead void usage(void) { (void)fprintf(stderr, "Usage: %s [-AadefILlNnOopqStvXx] [-B fildrop] [-c count] [-D direction]\n", program_name); (void)fprintf(stderr, "\t [-E [espalg:]espkey] [-F file] [-i interface] [-r file]\n"); (void)fprintf(stderr, "\t [-s snaplen] [-T type] [-w file] [-y datalinktype] [expression]\n"); exit(1); }