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/* snoop.c
*
* $Id: snoop.c,v 1.4 1999/03/01 18:57:07 gram 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.
*
*/
#include "wtap.h"
#include "buffer.h"
#include "snoop.h"
#include <netinet/in.h>
/* 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 */
};
/* Returns WTAP_FILE_SNOOP on success, WTAP_FILE_UNKNOWN on failure */
int snoop_open(wtap *wth)
{
int bytes_read;
char magic[sizeof snoop_magic];
struct snoop_hdr hdr;
static const int snoop_encap[] = {
WTAP_ENCAP_NONE, /* IEEE 802.3 */
WTAP_ENCAP_NONE, /* IEEE 802.4 Token Bus */
WTAP_ENCAP_TR,
WTAP_ENCAP_NONE, /* IEEE 802.6 Metro Net */
WTAP_ENCAP_ETHERNET,
WTAP_ENCAP_NONE, /* HDLC */
WTAP_ENCAP_NONE, /* Character Synchronous */
WTAP_ENCAP_NONE, /* IBM Channel-to-Channel */
WTAP_ENCAP_FDDI,
WTAP_ENCAP_NONE /* 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 */
fseek(wth->fh, 0, SEEK_SET);
bytes_read = fread(magic, 1, sizeof magic, wth->fh);
if (bytes_read != sizeof magic) {
return WTAP_FILE_UNKNOWN;
}
if (memcmp(magic, snoop_magic, sizeof snoop_magic) != 0) {
return WTAP_FILE_UNKNOWN;
}
/* Read the rest of the header. */
bytes_read = fread(&hdr, 1, sizeof hdr, wth->fh);
if (bytes_read != sizeof hdr) {
return WTAP_FILE_UNKNOWN;
}
hdr.version = ntohl(hdr.version);
if (hdr.version != 2) {
/* We only support version 2. */
return WTAP_FILE_UNKNOWN;
}
hdr.network = ntohl(hdr.network);
if (hdr.network >= NUM_SNOOP_ENCAPS) {
g_error("snoop: network type %d unknown", hdr.network);
return WTAP_FILE_UNKNOWN;
}
/* This is a snoop file */
wth->subtype_read = snoop_read;
wth->file_encap = snoop_encap[hdr.network];
wth->snapshot_length = 16384; /* XXX - not available in header */
return WTAP_FILE_SNOOP;
}
/* Read the next packet */
int snoop_read(wtap *wth)
{
int packet_size;
int bytes_read;
struct snooprec_hdr hdr;
int data_offset;
/* Read record header. */
bytes_read = fread(&hdr, 1, sizeof hdr, wth->fh);
if (bytes_read != sizeof hdr) {
if (bytes_read != 0) {
g_error("snoop_read: not enough packet header data (%d bytes)",
bytes_read);
return -1;
}
return 0;
}
packet_size = ntohl(hdr.incl_len);
buffer_assure_space(wth->frame_buffer, packet_size);
data_offset = ftell(wth->fh);
bytes_read = fread(buffer_start_ptr(wth->frame_buffer), 1,
packet_size, wth->fh);
if (bytes_read != packet_size) {
if (ferror(wth->fh)) {
g_error("snoop_read: fread for data: read error\n");
} else {
g_error("snoop_read: fread for data: %d bytes out of %d",
bytes_read, packet_size);
}
return -1;
}
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. */
fseek(wth->fh, ntohl(hdr.rec_len) - (sizeof hdr + packet_size),
SEEK_CUR);
return data_offset;
}
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