tcpdump.c

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/*
 * 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 <[e-mail]>
 */

#ifndef lint
static const char copyright[] _U_ =
    "@(#) 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[] _U_ =
    "@(#) $Header: /tcpdump/master/tcpdump/tcpdump.c,v 1.271.2.11 2008-09-25 21:50:04 guy Exp $ (LBL)";
#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 <tcpdump-stdinc.h>

#ifdef WIN32
#include "getopt.h"
#include "w32_fzs.h"
extern int strcasecmp (const char *__s1, const char *__s2);
extern int SIZE_BUF;
#define off_t long
#define uint UINT
#endif /* WIN32 */

#ifdef HAVE_SMI_H
#include <smi.h>
#endif

#include <pcap.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#ifndef WIN32
#include <sys/wait.h>
#include <sys/resource.h>
#include <pwd.h>
#include <grp.h>
#include <errno.h>
#endif /* WIN32 */


#include "netdissect.h"
#include "interface.h"
#include "addrtoname.h"
#include "machdep.h"
#include "setsignal.h"
#include "gmt2local.h"
#include "pcap-missing.h"

#ifndef NAME_MAX
#define NAME_MAX 255
#endif

netdissect_options Gndo;
netdissect_options *gndo = &Gndo;

int dflag;			/* print filter code */
int Lflag;			/* list available data link types and exit */
char *zflag = NULL;		/* compress each savefile using a specified command (like gzip or bzip2) */

static int infodelay;
static int infoprint;

char *program_name;

int32_t thiszone;		/* seconds offset from gmt to local time */

/* Forwards */
static RETSIGTYPE cleanup(int);
static RETSIGTYPE child_cleanup(int);
static void usage(void) __attribute__((noreturn));
static void show_dlts_and_exit(pcap_t *pd) __attribute__((noreturn));

static void print_packet(u_char *, const struct pcap_pkthdr *, const u_char *);
static void ndo_default_print(netdissect_options *, const u_char *, u_int);
static void dump_packet_and_trunc(u_char *, const struct pcap_pkthdr *, const u_char *);
static void dump_packet(u_char *, const struct pcap_pkthdr *, const u_char *);
static void droproot(const char *, const char *);
static void ndo_error(netdissect_options *ndo, const char *fmt, ...);
static void ndo_warning(netdissect_options *ndo, const char *fmt, ...);

#ifdef SIGINFO
RETSIGTYPE requestinfo(int);
#endif

#if defined(USE_WIN32_MM_TIMER)
  #include <MMsystem.h>
  static UINT timer_id;
  static void CALLBACK verbose_stats_dump(UINT, UINT, DWORD_PTR, DWORD_PTR, DWORD_PTR);
#elif defined(HAVE_ALARM)
  static void verbose_stats_dump(int sig);
#endif

static void info(int);
static u_int packets_captured;

typedef u_int (*if_printer)(const struct pcap_pkthdr *, const u_char *);

struct printer {
	if_printer f;
	int type;
};

static struct printer printers[] = {
	{ arcnet_if_print,	DLT_ARCNET },
#ifdef DLT_ARCNET_LINUX
	{ arcnet_linux_if_print, DLT_ARCNET_LINUX },
#endif
	{ 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 },
#ifdef DLT_SLIP_BSDOS
	{ sl_bsdos_if_print,	DLT_SLIP_BSDOS },
#endif
	{ ppp_if_print,		DLT_PPP },
#ifdef DLT_PPP_WITHDIRECTION
	{ ppp_if_print,		DLT_PPP_WITHDIRECTION },
#endif
#ifdef DLT_PPP_BSDOS
	{ ppp_bsdos_if_print,	DLT_PPP_BSDOS },
#endif
	{ 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
#if defined(DLT_PFLOG) && defined(HAVE_NET_PFVAR_H)
	{ pflog_if_print, 	DLT_PFLOG },
#endif
#ifdef DLT_FR
	{ fr_if_print,		DLT_FR },
#endif
#ifdef DLT_FRELAY
	{ fr_if_print,		DLT_FRELAY },
#endif
#ifdef DLT_SUNATM
	{ sunatm_if_print,	DLT_SUNATM },
#endif
#ifdef DLT_IP_OVER_FC
	{ ipfc_if_print,	DLT_IP_OVER_FC },
#endif
#ifdef DLT_PRISM_HEADER
	{ prism_if_print,	DLT_PRISM_HEADER },
#endif
#ifdef DLT_IEEE802_11_RADIO
	{ ieee802_11_radio_if_print,	DLT_IEEE802_11_RADIO },
#endif
#ifdef DLT_ENC
	{ enc_if_print, 	DLT_ENC },
#endif
#ifdef DLT_SYMANTEC_FIREWALL
	{ symantec_if_print, 	DLT_SYMANTEC_FIREWALL },
#endif
#ifdef DLT_APPLE_IP_OVER_IEEE1394
	{ ap1394_if_print,	DLT_APPLE_IP_OVER_IEEE1394 },
#endif
#ifdef DLT_IEEE802_11_RADIO_AVS
	{ ieee802_11_radio_avs_if_print,	DLT_IEEE802_11_RADIO_AVS },
#endif
#ifdef DLT_JUNIPER_ATM1
	{ juniper_atm1_print,	DLT_JUNIPER_ATM1 },
#endif
#ifdef DLT_JUNIPER_ATM2
	{ juniper_atm2_print,	DLT_JUNIPER_ATM2 },
#endif
#ifdef DLT_JUNIPER_MFR
	{ juniper_mfr_print,	DLT_JUNIPER_MFR },
#endif
#ifdef DLT_JUNIPER_MLFR
	{ juniper_mlfr_print,	DLT_JUNIPER_MLFR },
#endif
#ifdef DLT_JUNIPER_MLPPP
	{ juniper_mlppp_print,	DLT_JUNIPER_MLPPP },
#endif
#ifdef DLT_JUNIPER_PPPOE
	{ juniper_pppoe_print,	DLT_JUNIPER_PPPOE },
#endif
#ifdef DLT_JUNIPER_PPPOE_ATM
	{ juniper_pppoe_atm_print, DLT_JUNIPER_PPPOE_ATM },
#endif
#ifdef DLT_JUNIPER_GGSN
	{ juniper_ggsn_print,	DLT_JUNIPER_GGSN },
#endif
#ifdef DLT_JUNIPER_ES
	{ juniper_es_print,	DLT_JUNIPER_ES },
#endif
#ifdef DLT_JUNIPER_MONITOR
	{ juniper_monitor_print, DLT_JUNIPER_MONITOR },
#endif
#ifdef DLT_JUNIPER_SERVICES
	{ juniper_services_print, DLT_JUNIPER_SERVICES },
#endif
#ifdef DLT_JUNIPER_ETHER
	{ juniper_ether_print, DLT_JUNIPER_ETHER },
#endif
#ifdef DLT_JUNIPER_PPP
	{ juniper_ppp_print, DLT_JUNIPER_PPP },
#endif
#ifdef DLT_JUNIPER_FRELAY
	{ juniper_frelay_print, DLT_JUNIPER_FRELAY },
#endif
#ifdef DLT_JUNIPER_CHDLC
	{ juniper_chdlc_print, DLT_JUNIPER_CHDLC },
#endif
#ifdef DLT_MFR
	{ mfr_if_print, DLT_MFR },
#endif
#if defined(DLT_BLUETOOTH_HCI_H4_WITH_PHDR) && defined(HAVE_PCAP_BLUETOOTH_H)
	{ bt_if_print, DLT_BLUETOOTH_HCI_H4_WITH_PHDR},
#endif
	{ NULL,			0 },
};

static if_printer
lookup_printer(int type)
{
	struct printer *p;

	for (p = printers; p->f; ++p)
		if (type == p->type)
			return p->f;

	return NULL;
	/* NOTREACHED */
}

static pcap_t *pd;

extern int optind;
extern int opterr;
extern char *optarg;

struct print_info {
	if_printer printer;
};

struct dump_info {
	char	*WFileName;
	char	*CurrentFileName;
	pcap_t	*pd;
	pcap_dumper_t *p;
};

static void
show_dlts_and_exit(pcap_t *pd)
{
	int n_dlts;
	int *dlts = 0;
	const char *dlt_name;

	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 -y to set):\n");

	while (--n_dlts >= 0) {
		dlt_name = pcap_datalink_val_to_name(dlts[n_dlts]);
		if (dlt_name != NULL) {
			(void) fprintf(stderr, "  %s (%s)", dlt_name,
			    pcap_datalink_val_to_description(dlts[n_dlts]));

			/*
			 * OK, does tcpdump handle that type?
			 */
			if (lookup_printer(dlts[n_dlts]) == NULL)
				(void) fprintf(stderr, " (printing not supported)");
			putchar('\n');
		} else {
			(void) fprintf(stderr, "  DLT %d (printing not supported)\n",
			    dlts[n_dlts]);
		}
	}
	free(dlts);
	exit(0);
}

/*
 * Set up flags that might or might not be supported depending on the
 * version of libpcap we're using.
 */
#if defined(HAVE_PCAP_CREATE) || defined(WIN32)
#define B_FLAG		"B:"
#define B_FLAG_USAGE	" [ -B size ]"
#else /* defined(HAVE_PCAP_CREATE) || defined(WIN32) */
#define B_FLAG
#define B_FLAG_USAGE
#endif /* defined(HAVE_PCAP_CREATE) || defined(WIN32) */

#ifdef HAVE_PCAP_CREATE
#define I_FLAG		"I"
#else /* HAVE_PCAP_CREATE */
#define I_FLAG
#endif /* HAVE_PCAP_CREATE */

#ifdef HAVE_PCAP_FINDALLDEVS
#ifndef HAVE_PCAP_IF_T
#undef HAVE_PCAP_FINDALLDEVS
#endif
#endif

#ifdef HAVE_PCAP_FINDALLDEVS
#define D_FLAG	"D"
#else
#define D_FLAG
#endif

#ifdef HAVE_PCAP_DUMP_FLUSH
#define U_FLAG	"U"
#else
#define U_FLAG
#endif

#ifndef WIN32
/* Drop root privileges and chroot if necessary */
static void
droproot(const char *username, const char *chroot_dir)
{
	struct passwd *pw = NULL;

	if (chroot_dir && !username) {
		fprintf(stderr, "tcpdump: Chroot without dropping root is insecure\n");
		exit(1);
	}
	
	pw = getpwnam(username);
	if (pw) {
		if (chroot_dir) {
			if (chroot(chroot_dir) != 0 || chdir ("/") != 0) {
				fprintf(stderr, "tcpdump: Couldn't chroot/chdir to '%.64s': %s\n",
				    chroot_dir, pcap_strerror(errno));
				exit(1);
			}
		}
		if (initgroups(pw->pw_name, pw->pw_gid) != 0 ||
		    setgid(pw->pw_gid) != 0 || setuid(pw->pw_uid) != 0) {
			fprintf(stderr, "tcpdump: Couldn't change to '%.32s' uid=%lu gid=%lu: %s\n",
			    username, 
			    (unsigned long)pw->pw_uid,
			    (unsigned long)pw->pw_gid,
			    pcap_strerror(errno));
			exit(1);
		}
	}
	else {
		fprintf(stderr, "tcpdump: Couldn't find user '%.32s'\n",
		    username);
		exit(1);
	}
}
#endif /* WIN32 */

static int
getWflagChars(int x)
{
	int c = 0;

	x -= 1;
	while (x > 0) {
		c += 1;
		x /= 10;
	}

	return c;
}


static void
MakeFilename(char *buffer, char *orig_name, int cnt, int max_chars)
{
        char *filename = malloc(NAME_MAX + 1);

        /* Process with strftime if Gflag is set. */
        if (Gflag != 0) {
          struct tm *local_tm;

          /* Convert Gflag_time to a usable format */
          if ((local_tm = localtime(&Gflag_time)) == NULL) {
                  error("MakeTimedFilename: localtime");
          }

          /* There's no good way to detect an error in strftime since a return
           * value of 0 isn't necessarily failure.
           */
          strftime(filename, NAME_MAX, orig_name, local_tm);
        } else {
          strncpy(filename, orig_name, NAME_MAX);
        }

	if (cnt == 0 && max_chars == 0)
		strncpy(buffer, filename, NAME_MAX + 1);
	else
		if (snprintf(buffer, NAME_MAX + 1, "%s%0*d", filename, max_chars, cnt) > NAME_MAX)
                  /* Report an error if the filename is too large */
                  error("too many output files or filename is too long (> %d)", NAME_MAX);
        free(filename);
}

static int tcpdump_printf(netdissect_options *ndo _U_,
			  const char *fmt, ...)
{
  
  va_list args;
  int ret;

  va_start(args, fmt);
  ret=vfprintf(stdout, fmt, args);
  va_end(args);

  return ret;
}

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 callback;
	int type;
	struct bpf_program fcode;
#ifndef WIN32
	RETSIGTYPE (*oldhandler)(int);
#endif
	struct print_info printinfo;
	struct dump_info dumpinfo;
	u_char *pcap_userdata;
	char ebuf[PCAP_ERRBUF_SIZE];
	char *username = NULL;
	char *chroot_dir = NULL;
#ifdef HAVE_PCAP_FINDALLDEVS
	pcap_if_t *devpointer;
	int devnum;
#endif
	int status;
#ifdef WIN32
	if(wsockinit() != 0) return 1;
#endif /* WIN32 */

        gndo->ndo_Oflag=1;
	gndo->ndo_Rflag=1;
	gndo->ndo_dlt=-1;
	gndo->ndo_default_print=ndo_default_print;
	gndo->ndo_printf=tcpdump_printf;
	gndo->ndo_error=ndo_error;
	gndo->ndo_warning=ndo_warning;
	gndo->ndo_snaplen = DEFAULT_SNAPLEN;
  
	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, "aA" B_FLAG "c:C:d" D_FLAG "eE:fF:G:i:" I_FLAG "KlLm:M:nNOpqr:Rs:StT:u" U_FLAG "vw:W:xXy:Yz:Z:")) != -1)
		switch (op) {

		case 'a':
			/* compatibility for old -a */
			break;

		case 'A':
			++Aflag;
			break;

#if defined(HAVE_PCAP_CREATE) || defined(WIN32)
		case 'B':
			Bflag = atoi(optarg)*1024;
			if (Bflag <= 0)
				error("invalid packet buffer size %s", optarg);
			break;
#endif /* defined(HAVE_PCAP_CREATE) || defined(WIN32) */

		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;

#ifdef HAVE_PCAP_FINDALLDEVS
		case 'D':
			if (pcap_findalldevs(&devpointer, ebuf) < 0)
				error("%s", ebuf);