189 lines
5.0 KiB
C
189 lines
5.0 KiB
C
/* snoop.c
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*
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* $Id: snoop.c,v 1.7 1999/08/22 02:29:38 guy Exp $
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*
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* Wiretap Library
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* Copyright (c) 1998 by Gilbert Ramirez <gram@verdict.uthscsa.edu>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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*/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include <errno.h>
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#include "wtap.h"
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#include "buffer.h"
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#include "snoop.h"
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#ifdef HAVE_NETINET_IN_H
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#include <netinet/in.h>
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#endif
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/* See RFC 1761 for a description of the "snoop" file format. */
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/* Magic number in "snoop" files. */
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static const char snoop_magic[] = {
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's', 'n', 'o', 'o', 'p', '\0', '\0', '\0'
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};
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/* "snoop" file header (minus magic number). */
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struct snoop_hdr {
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guint32 version; /* version number (should be 2) */
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guint32 network; /* network type */
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};
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/* "snoop" record header. */
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struct snooprec_hdr {
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guint32 orig_len; /* actual length of packet */
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guint32 incl_len; /* number of octets captured in file */
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guint32 rec_len; /* length of record */
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guint32 cum_drops; /* cumulative number of dropped packets */
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guint32 ts_sec; /* timestamp seconds */
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guint32 ts_usec; /* timestamp microseconds */
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};
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static int snoop_read(wtap *wth, int *err);
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int snoop_open(wtap *wth, int *err)
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{
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int bytes_read;
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char magic[sizeof snoop_magic];
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struct snoop_hdr hdr;
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static const int snoop_encap[] = {
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WTAP_ENCAP_UNKNOWN, /* IEEE 802.3 */
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WTAP_ENCAP_UNKNOWN, /* IEEE 802.4 Token Bus */
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WTAP_ENCAP_TR,
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WTAP_ENCAP_UNKNOWN, /* IEEE 802.6 Metro Net */
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WTAP_ENCAP_ETHERNET,
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WTAP_ENCAP_UNKNOWN, /* HDLC */
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WTAP_ENCAP_UNKNOWN, /* Character Synchronous */
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WTAP_ENCAP_UNKNOWN, /* IBM Channel-to-Channel */
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WTAP_ENCAP_FDDI,
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WTAP_ENCAP_UNKNOWN /* Other */
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};
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#define NUM_SNOOP_ENCAPS (sizeof snoop_encap / sizeof snoop_encap[0])
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/* Read in the string that should be at the start of a "snoop" file */
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fseek(wth->fh, 0, SEEK_SET);
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errno = WTAP_ERR_CANT_READ;
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bytes_read = fread(magic, 1, sizeof magic, wth->fh);
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if (bytes_read != sizeof magic) {
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if (ferror(wth->fh)) {
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*err = errno;
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return -1;
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}
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return 0;
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}
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if (memcmp(magic, snoop_magic, sizeof snoop_magic) != 0) {
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return 0;
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}
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/* Read the rest of the header. */
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errno = WTAP_ERR_CANT_READ;
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bytes_read = fread(&hdr, 1, sizeof hdr, wth->fh);
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if (bytes_read != sizeof hdr) {
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if (ferror(wth->fh)) {
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*err = errno;
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return -1;
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}
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return 0;
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}
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hdr.version = ntohl(hdr.version);
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if (hdr.version != 2) {
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/* We only support version 2. */
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g_message("snoop: version %u unsupported", hdr.version);
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*err = WTAP_ERR_UNSUPPORTED;
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return -1;
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}
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hdr.network = ntohl(hdr.network);
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if (hdr.network >= NUM_SNOOP_ENCAPS
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|| snoop_encap[hdr.network] == WTAP_ENCAP_UNKNOWN) {
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g_message("snoop: network type %u unknown or unsupported",
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hdr.network);
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*err = WTAP_ERR_UNSUPPORTED;
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return -1;
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}
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/* This is a snoop file */
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wth->file_type = WTAP_FILE_SNOOP;
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wth->subtype_read = snoop_read;
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wth->file_encap = snoop_encap[hdr.network];
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wth->snapshot_length = 16384; /* XXX - not available in header */
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return 1;
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}
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/* Read the next packet */
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static int snoop_read(wtap *wth, int *err)
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{
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guint32 packet_size;
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int bytes_read;
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struct snooprec_hdr hdr;
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int data_offset;
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/* Read record header. */
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errno = WTAP_ERR_CANT_READ;
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bytes_read = fread(&hdr, 1, sizeof hdr, wth->fh);
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if (bytes_read != sizeof hdr) {
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if (ferror(wth->fh)) {
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*err = errno;
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return -1;
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}
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if (bytes_read != 0) {
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*err = WTAP_ERR_SHORT_READ;
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return -1;
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}
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return 0;
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}
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packet_size = ntohl(hdr.incl_len);
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if (packet_size > WTAP_MAX_PACKET_SIZE) {
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/*
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* Probably a corrupt capture file; don't blow up trying
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* to allocate space for an immensely-large packet.
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*/
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g_message("snoop: File has %u-byte packet, bigger than maximum of %u",
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packet_size, WTAP_MAX_PACKET_SIZE);
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*err = WTAP_ERR_BAD_RECORD;
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return -1;
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}
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buffer_assure_space(wth->frame_buffer, packet_size);
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data_offset = ftell(wth->fh);
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errno = WTAP_ERR_CANT_READ;
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bytes_read = fread(buffer_start_ptr(wth->frame_buffer), 1,
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packet_size, wth->fh);
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if (bytes_read != packet_size) {
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if (ferror(wth->fh))
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*err = errno;
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else
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*err = WTAP_ERR_SHORT_READ;
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return -1;
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}
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wth->phdr.ts.tv_sec = ntohl(hdr.ts_sec);
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wth->phdr.ts.tv_usec = ntohl(hdr.ts_usec);
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wth->phdr.caplen = packet_size;
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wth->phdr.len = ntohl(hdr.orig_len);
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wth->phdr.pkt_encap = wth->file_encap;
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/* Skip over the padding. */
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fseek(wth->fh, ntohl(hdr.rec_len) - (sizeof hdr + packet_size),
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SEEK_CUR);
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return data_offset;
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}
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