269 lines
7.1 KiB
C
269 lines
7.1 KiB
C
/* follow.c
|
|
*
|
|
* $Id: follow.c,v 1.17 1999/11/18 21:04:53 guy Exp $
|
|
*
|
|
* Copyright 1998 Mike Hall <mlh@io.com>
|
|
*
|
|
* Ethereal - Network traffic analyzer
|
|
* By Gerald Combs <gerald@zing.org>
|
|
* Copyright 1998 Gerald Combs
|
|
*
|
|
*
|
|
* 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 <gtk/gtk.h>
|
|
#include <stdlib.h>
|
|
#include <stdio.h>
|
|
#include <string.h>
|
|
#ifdef HAVE_UNISTD_H
|
|
#include <unistd.h>
|
|
#endif
|
|
|
|
#ifdef HAVE_SYS_TYPES_H
|
|
# include <sys/types.h>
|
|
#endif
|
|
|
|
#include <glib.h>
|
|
#include "gtk/main.h"
|
|
#include "packet.h"
|
|
#include "follow.h"
|
|
|
|
extern FILE* data_out_file;
|
|
|
|
gboolean incomplete_tcp_stream = FALSE;
|
|
|
|
static guint32 ip_address[2];
|
|
static u_int tcp_port[2];
|
|
|
|
static int check_fragments( int );
|
|
static void write_packet_data( const char *, int );
|
|
|
|
/* this will build libpcap filter text that will only
|
|
pass the packets related to the stream. There is a
|
|
chance that two streams could intersect, but not a
|
|
very good one */
|
|
char*
|
|
build_follow_filter( packet_info *pi ) {
|
|
char* buf = malloc(1024);
|
|
if( pi->net_src.type == AT_IPv4 && pi->net_dst.type == AT_IPv4
|
|
&& pi->ipproto == 6 ) {
|
|
/* TCP over IPv4 */
|
|
sprintf( buf,
|
|
"(ip.addr eq %s and ip.addr eq %s) and (tcp.port eq %d and tcp.port eq %d)",
|
|
ip_to_str( pi->net_src.data),
|
|
ip_to_str( pi->net_dst.data),
|
|
pi->srcport, pi->destport );
|
|
}
|
|
else {
|
|
free( buf );
|
|
return NULL;
|
|
}
|
|
memcpy(&ip_address[0], pi->net_src.data, sizeof ip_address[0]);
|
|
memcpy(&ip_address[1], pi->net_dst.data, sizeof ip_address[1]);
|
|
tcp_port[0] = pi->srcport;
|
|
tcp_port[1] = pi->destport;
|
|
return buf;
|
|
}
|
|
|
|
/* here we are going to try and reconstruct the data portion of a TCP
|
|
session. We will try and handle duplicates, TCP fragments, and out
|
|
of order packets in a smart way. */
|
|
|
|
static tcp_frag *frags[2] = { 0, 0};
|
|
static u_long seq[2];
|
|
static guint32 src[2] = { 0, 0 };
|
|
|
|
void
|
|
reassemble_tcp( u_long sequence, u_long length, const char* data,
|
|
u_long data_length, int synflag, address *net_src,
|
|
address *net_dst, u_int srcport, u_int dstport ) {
|
|
guint32 srcx, dstx;
|
|
int src_index, j, first = 0;
|
|
u_long newseq;
|
|
tcp_frag *tmp_frag;
|
|
src_index = -1;
|
|
|
|
/* first check if this packet should be processed */
|
|
if (net_src->type != AT_IPv4 || net_dst->type != AT_IPv4)
|
|
return;
|
|
memcpy(&srcx, net_src->data, sizeof srcx);
|
|
memcpy(&dstx, net_dst->data, sizeof dstx);
|
|
if ((srcx != ip_address[0] && srcx != ip_address[1]) ||
|
|
(dstx != ip_address[0] && dstx != ip_address[1]) ||
|
|
(srcport != tcp_port[0] && srcport != tcp_port[1]) ||
|
|
(dstport != tcp_port[0] && dstport != tcp_port[1]))
|
|
return;
|
|
|
|
/* first we check to see if we have seen this src ip before. */
|
|
for( j=0; j<2; j++ ) {
|
|
if( src[j] == srcx ) {
|
|
src_index = j;
|
|
}
|
|
}
|
|
/* we didn't find it if src_index == -1 */
|
|
if( src_index < 0 ) {
|
|
/* assign it to a src_index and get going */
|
|
for( j=0; j<2; j++ ) {
|
|
if( src[j] == 0 ) {
|
|
src[j] = srcx;
|
|
src_index = j;
|
|
first = 1;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
if( src_index < 0 ) {
|
|
fprintf( stderr, "ERROR in reassemble_tcp: Too many addresses!\n");
|
|
return;
|
|
}
|
|
|
|
if( data_length < length ) {
|
|
incomplete_tcp_stream = TRUE;
|
|
}
|
|
|
|
/* now that we have filed away the srcs, lets get the sequence number stuff
|
|
figured out */
|
|
if( first ) {
|
|
/* this is the first time we have seen this src's sequence number */
|
|
seq[src_index] = sequence + length;
|
|
if( synflag ) {
|
|
seq[src_index]++;
|
|
}
|
|
/* write out the packet data */
|
|
write_packet_data( data, data_length );
|
|
return;
|
|
}
|
|
/* if we are here, we have already seen this src, let's
|
|
try and figure out if this packet is in the right place */
|
|
if( sequence < seq[src_index] ) {
|
|
/* this sequence number seems dated, but
|
|
check the end to make sure it has no more
|
|
info than we have already seen */
|
|
newseq = sequence + length;
|
|
if( newseq > seq[src_index] ) {
|
|
u_long new_len;
|
|
|
|
/* this one has more than we have seen. let's get the
|
|
payload that we have not seen. */
|
|
|
|
new_len = seq[src_index] - sequence;
|
|
|
|
if ( data_length <= new_len ) {
|
|
data = NULL;
|
|
data_length = 0;
|
|
incomplete_tcp_stream = TRUE;
|
|
} else {
|
|
data += new_len;
|
|
data_length -= new_len;
|
|
}
|
|
sequence = seq[src_index];
|
|
length = newseq - seq[src_index];
|
|
|
|
/* this will now appear to be right on time :) */
|
|
}
|
|
}
|
|
if ( sequence == seq[src_index] ) {
|
|
/* right on time */
|
|
seq[src_index] += length;
|
|
if( synflag ) seq[src_index]++;
|
|
if( data ) {
|
|
write_packet_data( data, data_length );
|
|
}
|
|
/* done with the packet, see if it caused a fragment to fit */
|
|
while( check_fragments( src_index ) )
|
|
;
|
|
}
|
|
else {
|
|
/* out of order packet */
|
|
if( sequence > seq[src_index] ) {
|
|
tmp_frag = (tcp_frag *)malloc( sizeof( tcp_frag ) );
|
|
tmp_frag->data = (u_char *)malloc( data_length );
|
|
tmp_frag->seq = sequence;
|
|
tmp_frag->len = length;
|
|
tmp_frag->data_len = data_length;
|
|
memcpy( tmp_frag->data, data, data_length );
|
|
if( frags[src_index] ) {
|
|
tmp_frag->next = frags[src_index];
|
|
} else {
|
|
tmp_frag->next = NULL;
|
|
}
|
|
frags[src_index] = tmp_frag;
|
|
}
|
|
}
|
|
} /* end reassemble_tcp */
|
|
|
|
/* here we search through all the frag we have collected to see if
|
|
one fits */
|
|
static int
|
|
check_fragments( int index ) {
|
|
tcp_frag *prev = NULL;
|
|
tcp_frag *current;
|
|
current = frags[index];
|
|
while( current ) {
|
|
if( current->seq == seq[index] ) {
|
|
/* this fragment fits the stream */
|
|
if( current->data ) {
|
|
write_packet_data( current->data, current->data_len );
|
|
}
|
|
seq[index] += current->len;
|
|
if( prev ) {
|
|
prev->next = current->next;
|
|
} else {
|
|
frags[index] = current->next;
|
|
}
|
|
free( current->data );
|
|
free( current );
|
|
return 1;
|
|
}
|
|
prev = current;
|
|
current = current->next;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
/* this should always be called before we start to reassemble a stream */
|
|
void
|
|
reset_tcp_reassembly() {
|
|
tcp_frag *current, *next;
|
|
int i;
|
|
incomplete_tcp_stream = FALSE;
|
|
for( i=0; i<2; i++ ) {
|
|
seq[i] = 0;
|
|
src[i] = 0;
|
|
ip_address[i] = 0;
|
|
tcp_port[i] = 0;
|
|
current = frags[i];
|
|
while( current ) {
|
|
next = current->next;
|
|
free( current->data );
|
|
free( current );
|
|
current = next;
|
|
}
|
|
frags[i] = NULL;
|
|
}
|
|
}
|
|
|
|
static void
|
|
write_packet_data( const char* data, int length ) {
|
|
fwrite( data, 1, length, data_out_file );
|
|
}
|
|
|