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NetBSD/dist/tcpdump/tcpdump.c
thorpej c00254d517 * Add -D datalinktype to set the data link type to use when 
capturing packets.
* Add -L to list the known data link types and exit.

From David Young <dyoung@ojctech.com>, with some minor changes by me.
2002-09-22 16:59:16 +00:00

790 lines
17 KiB
C
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/* $NetBSD: tcpdump.c,v 1.6 2002/09/22 16:59:16 thorpej Exp $ */
/*
* Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 2000
* 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.
*
* Support for splitting captures into multiple files with a maximum
* file size:
*
* Copyright (c) 2001
* Seth Webster <swebster@sst.ll.mit.edu>
*/
#include <sys/cdefs.h>
#ifndef lint
#if 0
static const char copyright[] =
"@(#) Copyright (c) 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 2000\n\
The Regents of the University of California. All rights reserved.\n";
static const char rcsid[] =
"@(#) Header: /tcpdump/master/tcpdump/tcpdump.c,v 1.176 2002/05/16 10:25:58 guy Exp (LBL)";
#else
__RCSID("$NetBSD: tcpdump.c,v 1.6 2002/09/22 16:59:16 thorpej Exp $");
#endif
#endif
/*
* 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.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <sys/types.h>
#include <sys/time.h>
#include <netinet/in.h>
#include <pcap.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <ctype.h>
#include "interface.h"
#include "addrtoname.h"
#include "machdep.h"
#include "setsignal.h"
#include "gmt2local.h"
int aflag; /* translate network and broadcast addresses */
int dflag; /* print filter code */
int eflag; /* print ethernet header */
int fflag; /* don't translate "foreign" IP address */
int Lflag; /* list available data link types and exit */
int nflag; /* leave addresses as numbers */
int Nflag; /* remove domains from printed host names */
int Oflag = 1; /* run filter code optimizer */
int pflag; /* don't go promiscuous */
int qflag; /* quick (shorter) output */
int Rflag = 1; /* print sequence # field in AH/ESP*/
int sflag = 0; /* use the libsmi to translate OIDs */
int Sflag; /* print raw TCP sequence numbers */
int tflag = 1; /* print packet arrival time */
int uflag = 0; /* Print undecoded NFS handles */
int vflag; /* verbose */
int xflag; /* print packet in hex */
int Xflag; /* print packet in ascii as well as hex */
off_t Cflag = 0; /* rotate dump files after this many bytes */
int Aflag = 0; /* print packet only in ascii observing LF, CR, TAB, SPACE */
int dlt = -1; /* if != -1, ask libpcap for the DLT it names */
const char *dlt_name = NULL;
char *espsecret = NULL; /* ESP secret key */
int packettype;
int infodelay;
int infoprint;
char *program_name;
int32_t thiszone; /* seconds offset from gmt to local time */
/* Forwards */
static RETSIGTYPE cleanup(int);
static void usage(void) __attribute__((noreturn));
static void show_dlts_and_exit(pcap_t *pd) __attribute__((noreturn));
static void dump_and_trunc(u_char *, const struct pcap_pkthdr *, const u_char *);
#ifdef SIGINFO
RETSIGTYPE requestinfo(int);
#endif
/* Length of saved portion of packet. */
int snaplen = DEFAULT_SNAPLEN;
struct printer {
pcap_handler f;
int type;
};
static struct printer printers[] = {
{ arcnet_if_print, DLT_ARCNET },
{ ether_if_print, DLT_EN10MB },
{ token_if_print, DLT_IEEE802 },
#ifdef DLT_LANE8023
{ lane_if_print, DLT_LANE8023 },
#endif
#ifdef DLT_CIP
{ cip_if_print, DLT_CIP },
#endif
#ifdef DLT_ATM_CLIP
{ cip_if_print, DLT_ATM_CLIP },
#endif
{ sl_if_print, DLT_SLIP },
{ sl_bsdos_if_print, DLT_SLIP_BSDOS },
{ ppp_if_print, DLT_PPP },
{ ppp_bsdos_if_print, DLT_PPP_BSDOS },
{ fddi_if_print, DLT_FDDI },
{ null_if_print, DLT_NULL },
#ifdef DLT_LOOP
{ null_if_print, DLT_LOOP },
#endif
{ raw_if_print, DLT_RAW },
{ atm_if_print, DLT_ATM_RFC1483 },
#ifdef DLT_C_HDLC
{ chdlc_if_print, DLT_C_HDLC },
#endif
#ifdef DLT_HDLC
{ chdlc_if_print, DLT_HDLC },
#endif
#ifdef DLT_PPP_SERIAL
{ ppp_hdlc_if_print, DLT_PPP_SERIAL },
#endif
#ifdef DLT_PPP_ETHER
{ pppoe_if_print, DLT_PPP_ETHER },
#endif
#ifdef DLT_LINUX_SLL
{ sll_if_print, DLT_LINUX_SLL },
#endif
#ifdef DLT_IEEE802_11
{ ieee802_11_if_print, DLT_IEEE802_11},
#endif
#ifdef DLT_LTALK
{ ltalk_if_print, DLT_LTALK },
#endif
#ifdef DLT_PFLOG
{ pflog_if_print, DLT_PFLOG },
#endif
{ 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 %d", type);
/* NOTREACHED */
}
static pcap_t *pd;
extern int optind;
extern int opterr;
extern char *optarg;
struct dump_info {
char *WFileName;
pcap_t *pd;
pcap_dumper_t *p;
};
struct dlt_choice {
const char* name;
int dlt;
};
#define DLT_CHOICE(code) { #code, code }
#define DLT_CHOICE_SENTINEL { NULL, 0 }
struct dlt_choice dlt_choices[] = {
DLT_CHOICE(DLT_ARCNET),
DLT_CHOICE(DLT_EN10MB),
DLT_CHOICE(DLT_IEEE802),
#ifdef DLT_LANE8023
DLT_CHOICE(DLT_LANE8023),
#endif
#ifdef DLT_CIP
DLT_CHOICE(DLT_CIP),
#endif
#ifdef DLT_ATM_CLIP
DLT_CHOICE(DLT_ATM_CLIP),
#endif
DLT_CHOICE(DLT_SLIP),
DLT_CHOICE(DLT_SLIP_BSDOS),
DLT_CHOICE(DLT_PPP),
DLT_CHOICE(DLT_PPP_BSDOS),
DLT_CHOICE(DLT_FDDI),
DLT_CHOICE(DLT_NULL),
#ifdef DLT_LOOP
DLT_CHOICE(DLT_LOOP),
#endif
DLT_CHOICE(DLT_RAW),
DLT_CHOICE(DLT_ATM_RFC1483),
#ifdef DLT_C_HDLC
DLT_CHOICE(DLT_C_HDLC),
#endif
#ifdef DLT_HDLC
DLT_CHOICE(DLT_HDLC),
#endif
#ifdef DLT_PPP_SERIAL
DLT_CHOICE(DLT_PPP_SERIAL),
#endif
#ifdef DLT_PPP_ETHER
DLT_CHOICE(DLT_PPP_ETHER),
#endif
#ifdef DLT_LINUX_SLL
DLT_CHOICE(DLT_LINUX_SLL),
#endif
#ifdef DLT_IEEE802_11
DLT_CHOICE(DLT_IEEE802_11),
#endif
#ifdef DLT_LTALK
DLT_CHOICE(DLT_LTALK),
#endif
#ifdef DLT_PFLOG
DLT_CHOICE(DLT_PFLOG),
#endif
DLT_CHOICE_SENTINEL
};
static void
show_dlts_and_exit(pcap_t *pd)
{
int i, n_dlts;
int *dlts = 0;
n_dlts = pcap_list_datalinks(pd, &dlts);
if (n_dlts < 0)
error("%s", pcap_geterr(pd));
else if (n_dlts == 0 || !dlts)
error("No data link types.");
(void) fprintf(stderr, "Data link types (use option -D):\n");
while (--n_dlts >= 0) {
for (i = 0; dlt_choices[i].name; i++) {
if (dlt_choices[i].dlt != dlts[n_dlts]) {
continue;
}
(void) fprintf(stderr, " %s\n",
dlt_choices[i].name + sizeof("DLT_") - 1);
break;
}
if (!dlt_choices[i].name)
fprintf(stderr, " %d (not supported)\n", dlts[n_dlts]);
}
free(dlts);
exit(0);
}
int
main(int argc, char **argv)
{
register int cnt, op, i;
bpf_u_int32 localnet, netmask;
register char *cp, *infile, *cmdbuf, *device, *RFileName, *WFileName;
pcap_handler printer;
struct bpf_program fcode;
RETSIGTYPE (*oldhandler)(int);
struct dump_info dumpinfo;
u_char *pcap_userdata;
char ebuf[PCAP_ERRBUF_SIZE];
cnt = -1;
device = NULL;
infile = NULL;
RFileName = NULL;
WFileName = NULL;
if ((cp = strrchr(argv[0], '/')) != NULL)
program_name = cp + 1;
else
program_name = argv[0];
if (abort_on_misalignment(ebuf, sizeof(ebuf)) < 0)
error("%s", ebuf);
#ifdef LIBSMI
smiInit("tcpdump");
#endif
opterr = 0;
while (
(op = getopt(argc, argv, "aAc:C:dD:eE:fF:i:lLm:nNOpqr:Rs:StT:uvw:xXY")) != -1)
switch (op) {
case 'a':
++aflag;
break;
case 'A':
++xflag;
++Xflag;
++Aflag;
break;
case 'c':
cnt = atoi(optarg);
if (cnt <= 0)
error("invalid packet count %s", optarg);
break;
case 'C':
Cflag = atoi(optarg) * 1000000;
if (Cflag < 0)
error("invalid file size %s", optarg);
break;
case 'd':
++dflag;
break;
case 'D':
for (i = 0; dlt_choices[i].name; i++) {
if (!strcasecmp(dlt_choices[i].name +
sizeof("DLT_") - 1,
optarg)) {
dlt = dlt_choices[i].dlt;
dlt_name = dlt_choices[i].name;
break;
}
}
if (dlt < 0) {
error("invalid data link type %s", optarg);
}
break;
case 'L':
Lflag++;
break;
case 'e':
++eflag;
break;
case 'E':
#ifndef HAVE_LIBCRYPTO
warning("crypto code not compiled in");
#endif
espsecret = optarg;
break;
case 'f':
++fflag;
break;
case 'F':
infile = optarg;
break;
case 'i':
device = optarg;
break;
case 'l':
#ifdef HAVE_SETLINEBUF
setlinebuf(stdout);
#else
setvbuf(stdout, NULL, _IOLBF, 0);
#endif
break;
case 'n':
++nflag;
break;
case 'N':
++Nflag;
break;
case 'm':
#ifdef LIBSMI
if (smiLoadModule(optarg) == 0) {
error("could not load MIB module %s", optarg);
}
sflag = 1;
#else
(void)fprintf(stderr, "%s: ignoring option `-m %s' ",
program_name, optarg);
(void)fprintf(stderr, "(no libsmi support)\n");
#endif
case 'O':
Oflag = 0;
break;
case 'p':
++pflag;
break;
case 'q':
++qflag;
break;
case 'r':
RFileName = optarg;
break;
case 'R':
Rflag = 0;
break;
case 's': {
char *end;
snaplen = strtol(optarg, &end, 0);
if (optarg == end || *end != '\0'
|| snaplen < 0 || snaplen > 65535)
error("invalid snaplen %s", optarg);
else if (snaplen == 0)
snaplen = 65535;
break;
}
case 'S':
++Sflag;
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, "snmp") == 0)
packettype = PT_SNMP;
else if (strcasecmp(optarg, "cnfp") == 0)
packettype = PT_CNFP;
else
error("unknown packet type `%s'", optarg);
break;
case 'u':
++uflag;
break;
case 'v':
++vflag;
break;
case 'w':
WFileName = optarg;
break;
case 'x':
++xflag;
break;
case 'X':
++xflag;
++Xflag;
break;
#ifdef YYDEBUG
case 'Y':
{
/* Undocumented flag */
extern int yydebug;
yydebug = 1;
}
break;
#endif
default:
usage();
/* NOTREACHED */
}
if (aflag && nflag)
error("-a and -n options are incompatible");
if (tflag > 0)
thiszone = gmt2local(0);
if (RFileName != NULL) {
/*
* We don't need network access, so set it back to the user id.
* Also, this prevents the user from reading anyone's
* trace file.
*/
setuid(getuid());
pd = pcap_open_offline(RFileName, ebuf);
if (pd == NULL)
error("%s", ebuf);
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);
}
*ebuf = '\0';
pd = pcap_open_live(device, snaplen, !pflag, 1000, ebuf);
if (pd == NULL)
error("%s", ebuf);
else if (*ebuf)
warning("%s", ebuf);
if (Lflag) {
show_dlts_and_exit(pd);
}
if (dlt >= 0) {
if (pcap_set_datalink(pd, dlt) < 0)
error("%s", pcap_geterr(pd));
(void)fprintf(stderr, "%s: data link type %s\n",
program_name, dlt_name);
(void)fflush(stderr);
}
i = pcap_snapshot(pd);
if (snaplen < i) {
warning("snaplen raised from %d to %d", snaplen, i);
snaplen = i;
}
if (pcap_lookupnet(device, &localnet, &netmask, ebuf) < 0) {
localnet = 0;
netmask = 0;
warning("%s", ebuf);
}
/*
* Let user own process after socket has been opened.
*/
setuid(getuid());
}
if (infile)
cmdbuf = read_infile(infile);
else
cmdbuf = copy_argv(&argv[optind]);
if (pcap_compile(pd, &fcode, cmdbuf, Oflag, netmask) < 0)
error("%s", pcap_geterr(pd));
if (dflag) {
bpf_dump(&fcode, dflag);
exit(0);
}
init_addrtoname(localnet, netmask);
(void)setsignal(SIGTERM, cleanup);
(void)setsignal(SIGINT, cleanup);
/* Cooperate with nohup(1) */
if ((oldhandler = setsignal(SIGHUP, cleanup)) != SIG_DFL)
(void)setsignal(SIGHUP, oldhandler);
if (pcap_setfilter(pd, &fcode) < 0)
error("%s", pcap_geterr(pd));
if (WFileName) {
pcap_dumper_t *p = pcap_dump_open(pd, WFileName);
if (p == NULL)
error("%s", pcap_geterr(pd));
if (Cflag != 0) {
printer = dump_and_trunc;
dumpinfo.WFileName = WFileName;
dumpinfo.pd = pd;
dumpinfo.p = p;
pcap_userdata = (u_char *)&dumpinfo;
} else {
printer = pcap_dump;
pcap_userdata = (u_char *)p;
}
} else {
printer = lookup_printer(pcap_datalink(pd));
pcap_userdata = 0;
#ifdef SIGINFO
(void)setsignal(SIGINFO, requestinfo);
#endif
}
if (RFileName == NULL) {
(void)fprintf(stderr, "%s: listening on %s\n",
program_name, device);
(void)fflush(stderr);
}
if (pcap_loop(pd, cnt, printer, pcap_userdata) < 0) {
(void)fprintf(stderr, "%s: pcap_loop: %s\n",
program_name, pcap_geterr(pd));
cleanup(0);
pcap_close(pd);
exit(1);
}
if (RFileName == NULL)
info(1);
pcap_close(pd);
exit(0);
}
/* make a clean exit on interrupts */
static RETSIGTYPE
cleanup(int signo)
{
/* Can't print the summary if reading from a savefile */
if (pd != NULL && pcap_file(pd) == NULL) {
(void)fflush(stdout);
putc('\n', stderr);
info(1);
}
if (signo)
exit(0);
}
void
info(register int verbose)
{
struct pcap_stat stat;
if (pcap_stats(pd, &stat) < 0) {
(void)fprintf(stderr, "pcap_stats: %s\n", pcap_geterr(pd));
return;
}
if (!verbose)
fprintf(stderr, "%s: ", program_name);
(void)fprintf(stderr, "%d packets received by filter", stat.ps_recv);
if (!verbose)
fputs(", ", stderr);
else
putc('\n', stderr);
(void)fprintf(stderr, "%d packets dropped by kernel\n", stat.ps_drop);
infoprint = 0;
}
static void
reverse(char *s)
{
int i, j, c;
for (i = 0, j = strlen(s) - 1; i < j; i++, j--) {
c = s[i];
s[i] = s[j];
s[j] = c;
}
}
static void
swebitoa(unsigned int n, char *s)
{
unsigned int i;
i = 0;
do {
s[i++] = n % 10 + '0';
} while ((n /= 10) > 0);
s[i] = '\0';
reverse(s);
}
static void
dump_and_trunc(u_char *user, const struct pcap_pkthdr *h, const u_char *sp)
{
struct dump_info *info;
static uint cnt = 2;
char *name;
info = (struct dump_info *)user;
/*
* XXX - this won't prevent capture files from getting
* larger than Cflag - the last packet written to the
* file could put it over Cflag.
*/
if (ftell((FILE *)info->p) > Cflag) {
name = (char *) malloc(strlen(info->WFileName) + 4);
if (name == NULL)
error("dump_and_trunc: malloc");
strcpy(name, info->WFileName);
swebitoa(cnt, name + strlen(info->WFileName));
cnt++;
pcap_dump_close(info->p);
info->p = pcap_dump_open(info->pd, name);
free(name);
if (info->p == NULL)
error("%s", pcap_geterr(pd));
}
pcap_dump((u_char *)info->p, h, sp);
}
/* Like default_print() but data need not be aligned */
void
default_print_unaligned(register const u_char *cp, register u_int length)
{
register u_int i, s;
register int nshorts;
if (Xflag) {
ascii_print(cp, length);
return;
}
nshorts = (u_int) length / sizeof(u_short);
i = 0;
while (--nshorts >= 0) {
if ((i++ % 8) == 0)
(void)printf("\n\t\t\t");
s = *cp++;
(void)printf(" %02x%02x", s, *cp++);
}
if (length & 1) {
if ((i % 8) == 0)
(void)printf("\n\t\t\t");
(void)printf(" %02x", *cp);
}
}
/*
* By default, print the packet out in hex.
*/
void
default_print(register const u_char *bp, register u_int length)
{
default_print_unaligned(bp, length);
}
#ifdef SIGINFO
RETSIGTYPE requestinfo(int signo)
{
if (infodelay)
++infoprint;
else
info(0);
}
#endif
static void
usage(void)
{
extern char version[];
extern char pcap_version[];
(void)fprintf(stderr, "%s version %s\n", program_name, version);
(void)fprintf(stderr, "libpcap version %s\n", pcap_version);
(void)fprintf(stderr,
"Usage: %s [-aAdeflLnNOpqRStuvxX] [ -D datalinktype ] [ -c count ] [ -C file_size ]\n", program_name);
(void)fprintf(stderr,
"\t\t[ -F file ] [ -i interface ] [ -r file ] [ -s snaplen ]\n");
(void)fprintf(stderr,
"\t\t[ -T type ] [ -w file ] [ -E algo:secret ] [ expression ]\n");
exit(1);
}
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