![Guy Harris](/assets/img/avatar_default.png)
wtap_file_read_expected_bytes() from an open routine - open routines are supposed to return -1 on error, 0 if the file doesn't appear to be a file of the specified type, or 1 if the file does appear to be a file of the specified type, but those macros will cause the caller to return FALSE on errors (so that, even if there's an I/O error, it reports "the file isn't a file of the specified type" rather than "we got an error trying to read the file"). When doing reads in an open routine before we've concluded that the file is probably of the right type, return 0, rather than -1, if we get WTAP_ERR_SHORT_READ - if we don't have enough data to check whether a file is of a given type, we should keep trying other types, not give up. For reads done *after* we've concluded the file is probably of the right type, if a read doesn't return the number of bytes we asked for, but returns an error of 0, return WTAP_ERR_SHORT_READ - the file is apparently cut short. For NetMon and NetXRay/Windows Sniffer files, use a #define for the magic number size, and use that for both magic numbers. svn path=/trunk/; revision=46803
257 lines
7.2 KiB
C
257 lines
7.2 KiB
C
/* csids.c
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*
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* $Id$
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*
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* Copyright (c) 2000 by Mike Hall <mlh@io.com>
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* Copyright (c) 2000 by Cisco Systems
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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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include "config.h"
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#include "wtap-int.h"
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#include "buffer.h"
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#include "csids.h"
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#include "file_wrappers.h"
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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/*
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* This module reads the output from the Cisco Secure Intrusion Detection
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* System iplogging facility. The term iplogging is misleading since this
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* logger will only output TCP. There is no link layer information.
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* Packet format is 4 byte timestamp (seconds since epoch), and a 4 byte size
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* of data following for that packet.
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*
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* For a time there was an error in iplogging and the ip length, flags, and id
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* were byteswapped. We will check for this and handle it before handing to
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* wireshark.
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*/
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static gboolean csids_read(wtap *wth, int *err, gchar **err_info,
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gint64 *data_offset);
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static gboolean csids_seek_read(wtap *wth, gint64 seek_off,
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struct wtap_pkthdr *phdr, guint8 *pd, int len,
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int *err, gchar **err_info);
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struct csids_header {
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guint32 seconds; /* seconds since epoch */
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guint16 zeropad; /* 2 byte zero'ed pads */
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guint16 caplen; /* the capture length */
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};
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typedef struct {
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gboolean byteswapped;
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} csids_t;
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/* XXX - return -1 on I/O error and actually do something with 'err'. */
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int csids_open(wtap *wth, int *err, gchar **err_info)
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{
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/* There is no file header. There is only a header for each packet
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* so we read a packet header and compare the caplen with iplen. They
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* should always be equal except with the wierd byteswap version.
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*
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* THIS IS BROKEN-- anytime the caplen is 0x0101 or 0x0202 up to 0x0505
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* this will byteswap it. I need to fix this. XXX --mlh
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*/
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int tmp,iplen,bytesRead;
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gboolean byteswap = FALSE;
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struct csids_header hdr;
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csids_t *csids;
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/* check the file to make sure it is a csids file. */
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bytesRead = file_read( &hdr, sizeof( struct csids_header), wth->fh );
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if( bytesRead != sizeof( struct csids_header) ) {
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*err = file_error( wth->fh, err_info );
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if( *err != 0 && *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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if( hdr.zeropad != 0 || hdr.caplen == 0 ) {
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return 0;
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}
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hdr.seconds = pntohl( &hdr.seconds );
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hdr.caplen = pntohs( &hdr.caplen );
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bytesRead = file_read( &tmp, 2, wth->fh );
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if( bytesRead != 2 ) {
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*err = file_error( wth->fh, err_info );
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if( *err != 0 && *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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bytesRead = file_read( &iplen, 2, wth->fh );
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if( bytesRead != 2 ) {
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*err = file_error( wth->fh, err_info );
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if( *err != 0 && *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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iplen = pntohs(&iplen);
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if ( iplen == 0 )
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return 0;
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/* if iplen and hdr.caplen are equal, default to no byteswap. */
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if( iplen > hdr.caplen ) {
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/* maybe this is just a byteswapped version. the iplen ipflags */
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/* and ipid are swapped. We cannot use the normal swaps because */
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/* we don't know the host */
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iplen = BSWAP16(iplen);
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if( iplen <= hdr.caplen ) {
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/* we know this format */
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byteswap = TRUE;
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} else {
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/* don't know this one */
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return 0;
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}
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} else {
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byteswap = FALSE;
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}
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/* no file header. So reset the fh to 0 so we can read the first packet */
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if (file_seek(wth->fh, 0, SEEK_SET, err) == -1)
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return -1;
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csids = (csids_t *)g_malloc(sizeof(csids_t));
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wth->priv = (void *)csids;
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csids->byteswapped = byteswap;
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wth->file_encap = WTAP_ENCAP_RAW_IP;
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wth->file_type = WTAP_FILE_CSIDS;
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wth->snapshot_length = 0; /* not known */
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wth->subtype_read = csids_read;
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wth->subtype_seek_read = csids_seek_read;
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wth->tsprecision = WTAP_FILE_TSPREC_SEC;
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return 1;
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}
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/* Find the next packet and parse it; called from wtap_read(). */
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static gboolean csids_read(wtap *wth, int *err, gchar **err_info,
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gint64 *data_offset)
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{
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csids_t *csids = (csids_t *)wth->priv;
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guint8 *buf;
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int bytesRead = 0;
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struct csids_header hdr;
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*data_offset = file_tell(wth->fh);
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bytesRead = file_read( &hdr, sizeof( struct csids_header) , wth->fh );
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if( bytesRead != sizeof( struct csids_header) ) {
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*err = file_error( wth->fh, err_info );
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if (*err == 0 && bytesRead != 0)
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*err = WTAP_ERR_SHORT_READ;
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return FALSE;
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}
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hdr.seconds = pntohl(&hdr.seconds);
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hdr.caplen = pntohs(&hdr.caplen);
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/* Make sure we have enough room for the packet */
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buffer_assure_space(wth->frame_buffer, hdr.caplen);
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buf = buffer_start_ptr(wth->frame_buffer);
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bytesRead = file_read( buf, hdr.caplen, wth->fh );
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if( bytesRead != hdr.caplen ) {
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*err = file_error( wth->fh, err_info );
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if (*err == 0)
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*err = WTAP_ERR_SHORT_READ;
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return FALSE;
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}
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wth->phdr.presence_flags = WTAP_HAS_TS;
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wth->phdr.len = hdr.caplen;
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wth->phdr.caplen = hdr.caplen;
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wth->phdr.ts.secs = hdr.seconds;
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wth->phdr.ts.nsecs = 0;
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if( csids->byteswapped ) {
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if( hdr.caplen >= 2 ) {
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PBSWAP16(buf); /* the ip len */
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if( hdr.caplen >= 4 ) {
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PBSWAP16(buf+2); /* ip id */
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if( hdr.caplen >= 6 )
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PBSWAP16(buf+4); /* ip flags and fragoff */
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}
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}
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}
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return TRUE;
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}
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/* Used to read packets in random-access fashion */
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static gboolean
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csids_seek_read (wtap *wth,
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gint64 seek_off,
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struct wtap_pkthdr *phdr _U_,
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guint8 *pd,
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int len,
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int *err,
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gchar **err_info)
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{
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csids_t *csids = (csids_t *)wth->priv;
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int bytesRead;
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struct csids_header hdr;
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if( file_seek( wth->random_fh, seek_off, SEEK_SET, err ) == -1 )
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return FALSE;
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bytesRead = file_read( &hdr, sizeof( struct csids_header), wth->random_fh );
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if( bytesRead != sizeof( struct csids_header) ) {
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*err = file_error( wth->random_fh, err_info );
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if( *err == 0 ) {
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*err = WTAP_ERR_SHORT_READ;
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}
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return FALSE;
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}
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hdr.seconds = pntohl(&hdr.seconds);
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hdr.caplen = pntohs(&hdr.caplen);
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if( len != hdr.caplen ) {
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*err = WTAP_ERR_BAD_FILE;
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*err_info = g_strdup_printf("csids: record length %u doesn't match requested length %d",
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hdr.caplen, len);
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return FALSE;
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}
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bytesRead = file_read( pd, hdr.caplen, wth->random_fh );
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if( bytesRead != hdr.caplen ) {
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*err = file_error( wth->random_fh, err_info );
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if( *err == 0 ) {
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*err = WTAP_ERR_SHORT_READ;
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}
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return FALSE;
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}
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if( csids->byteswapped ) {
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if( hdr.caplen >= 2 ) {
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PBSWAP16(pd); /* the ip len */
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if( hdr.caplen >= 4 ) {
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PBSWAP16(pd+2); /* ip id */
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if( hdr.caplen >= 6 )
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PBSWAP16(pd+4); /* ip flags and fragoff */
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}
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}
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}
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return TRUE;
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}
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