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/* snoop.c
*
* $Id: snoop.c,v 1.14 1999/10/05 07:06:07 guy Exp $
*
* Wiretap Library
* Copyright (c) 1998 by Gilbert Ramirez <gram@verdict.uthscsa.edu>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <errno.h>
#include "wtap.h"
#include "file.h"
#include "buffer.h"
#include "snoop.h"
#ifdef HAVE_NETINET_IN_H
#include <netinet/in.h>
#endif
/* See RFC 1761 for a description of the "snoop" file format. */
/* Magic number in "snoop" files. */
static const char snoop_magic[] = {
's', 'n', 'o', 'o', 'p', '\0', '\0', '\0'
};
/* "snoop" file header (minus magic number). */
struct snoop_hdr {
guint32 version; /* version number (should be 2) */
guint32 network; /* network type */
};
/* "snoop" record header. */
struct snooprec_hdr {
guint32 orig_len; /* actual length of packet */
guint32 incl_len; /* number of octets captured in file */
guint32 rec_len; /* length of record */
guint32 cum_drops; /* cumulative number of dropped packets */
guint32 ts_sec; /* timestamp seconds */
guint32 ts_usec; /* timestamp microseconds */
};
static int snoop_read(wtap *wth, int *err);
int snoop_open(wtap *wth, int *err)
{
int bytes_read;
char magic[sizeof snoop_magic];
struct snoop_hdr hdr;
static const int snoop_encap[] = {
WTAP_ENCAP_ETHERNET, /* IEEE 802.3 */
WTAP_ENCAP_UNKNOWN, /* IEEE 802.4 Token Bus */
WTAP_ENCAP_TR,
WTAP_ENCAP_UNKNOWN, /* IEEE 802.6 Metro Net */
WTAP_ENCAP_ETHERNET,
WTAP_ENCAP_UNKNOWN, /* HDLC */
WTAP_ENCAP_UNKNOWN, /* Character Synchronous */
WTAP_ENCAP_UNKNOWN, /* IBM Channel-to-Channel */
WTAP_ENCAP_FDDI_BITSWAPPED,
WTAP_ENCAP_UNKNOWN /* Other */
};
#define NUM_SNOOP_ENCAPS (sizeof snoop_encap / sizeof snoop_encap[0])
/* Read in the string that should be at the start of a "snoop" file */
file_seek(wth->fh, 0, SEEK_SET);
wth->data_offset = 0;
errno = WTAP_ERR_CANT_READ;
bytes_read = file_read(magic, 1, sizeof magic, wth->fh);
if (bytes_read != sizeof magic) {
*err = file_error(wth->fh);
if (*err != 0)
return -1;
return 0;
}
wth->data_offset += sizeof magic;
if (memcmp(magic, snoop_magic, sizeof snoop_magic) != 0) {
return 0;
}
/* Read the rest of the header. */
errno = WTAP_ERR_CANT_READ;
bytes_read = file_read(&hdr, 1, sizeof hdr, wth->fh);
if (bytes_read != sizeof hdr) {
*err = file_error(wth->fh);
if (*err != 0)
return -1;
return 0;
}
wth->data_offset += sizeof hdr;
hdr.version = ntohl(hdr.version);
if (hdr.version != 2) {
/* We only support version 2. */
g_message("snoop: version %u unsupported", hdr.version);
*err = WTAP_ERR_UNSUPPORTED;
return -1;
}
hdr.network = ntohl(hdr.network);
if (hdr.network >= NUM_SNOOP_ENCAPS
|| snoop_encap[hdr.network] == WTAP_ENCAP_UNKNOWN) {
g_message("snoop: network type %u unknown or unsupported",
hdr.network);
*err = WTAP_ERR_UNSUPPORTED;
return -1;
}
/* This is a snoop file */
wth->file_type = WTAP_FILE_SNOOP;
wth->subtype_read = snoop_read;
wth->file_encap = snoop_encap[hdr.network];
wth->snapshot_length = 16384; /* XXX - not available in header */
return 1;
}
/* Read the next packet */
static int snoop_read(wtap *wth, int *err)
{
guint32 packet_size;
int bytes_read;
struct snooprec_hdr hdr;
int data_offset;
char padbuf[4];
int padbytes;
int bytes_to_read;
/* Read record header. */
errno = WTAP_ERR_CANT_READ;
bytes_read = file_read(&hdr, 1, sizeof hdr, wth->fh);
if (bytes_read != sizeof hdr) {
*err = file_error(wth->fh);
if (*err != 0)
return -1;
if (bytes_read != 0) {
*err = WTAP_ERR_SHORT_READ;
return -1;
}
return 0;
}
wth->data_offset += sizeof hdr;
packet_size = ntohl(hdr.incl_len);
if (packet_size > WTAP_MAX_PACKET_SIZE) {
/*
* Probably a corrupt capture file; don't blow up trying
* to allocate space for an immensely-large packet.
*/
g_message("snoop: File has %u-byte packet, bigger than maximum of %u",
packet_size, WTAP_MAX_PACKET_SIZE);
*err = WTAP_ERR_BAD_RECORD;
return -1;
}
buffer_assure_space(wth->frame_buffer, packet_size);
data_offset = wth->data_offset;
errno = WTAP_ERR_CANT_READ;
bytes_read = file_read(buffer_start_ptr(wth->frame_buffer), 1,
packet_size, wth->fh);
if (bytes_read != packet_size) {
*err = file_error(wth->fh);
if (*err == 0)
*err = WTAP_ERR_SHORT_READ;
return -1;
}
wth->data_offset += packet_size;
wth->phdr.ts.tv_sec = ntohl(hdr.ts_sec);
wth->phdr.ts.tv_usec = ntohl(hdr.ts_usec);
wth->phdr.caplen = packet_size;
wth->phdr.len = ntohl(hdr.orig_len);
wth->phdr.pkt_encap = wth->file_encap;
/*
* Skip over the padding (don't "fseek()", as the standard
* I/O library on some platforms discards buffered data if
* you do that, which means it does a lot more reads).
* There's probably not much padding (it's probably padded only
* to a 4-byte boundary), so we probably need only do one read.
*/
padbytes = ntohl(hdr.rec_len) - (sizeof hdr + packet_size);
while (padbytes != 0) {
bytes_to_read = padbytes;
if (bytes_to_read > sizeof padbuf)
bytes_to_read = sizeof padbuf;
errno = WTAP_ERR_CANT_READ;
bytes_read = file_read(padbuf, 1, bytes_to_read, wth->fh);
if (bytes_read != bytes_to_read) {
*err = file_error(wth->fh);
if (*err == 0)
*err = WTAP_ERR_SHORT_READ;
return -1;
}
wth->data_offset += bytes_read;
padbytes -= bytes_read;
}
return data_offset;
}
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