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-rw-r--r--epan/follow.c336
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diff --git a/epan/follow.c b/epan/follow.c
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+/* follow.c
+ *
+ * $Id$
+ *
+ * Copyright 1998 Mike Hall <mlh@io.com>
+ *
+ * Ethereal - Network traffic analyzer
+ * By Gerald Combs <gerald@ethereal.com>
+ * 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 <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#ifdef HAVE_UNISTD_H
+#include <unistd.h>
+#endif
+
+#include <glib.h>
+#include <epan/packet.h>
+#include "follow.h"
+
+#define MAX_IPADDR_LEN 16
+
+typedef struct _tcp_frag {
+ gulong seq;
+ gulong len;
+ gulong data_len;
+ gchar *data;
+ struct _tcp_frag *next;
+} tcp_frag;
+
+FILE* data_out_file = NULL;
+
+gboolean incomplete_tcp_stream = FALSE;
+
+static guint8 ip_address[2][MAX_IPADDR_LEN];
+static guint tcp_port[2];
+static guint bytes_written[2];
+static gboolean is_ipv6 = FALSE;
+
+static int check_fragments( int, tcp_stream_chunk * );
+static void write_packet_data( int, tcp_stream_chunk *, const char * );
+
+void
+follow_tcp_stats(follow_tcp_stats_t* stats)
+{
+ int i;
+
+ for (i = 0; i < 2 ; i++) {
+ memcpy(stats->ip_address[i], ip_address[i], MAX_IPADDR_LEN);
+ stats->tcp_port[i] = tcp_port[i];
+ stats->bytes_written[i] = bytes_written[i];
+ stats->is_ipv6 = is_ipv6;
+ }
+}
+
+/* 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 = g_malloc(1024);
+ int len;
+ 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 );
+ len = 4;
+ is_ipv6 = FALSE;
+ }
+ else if( pi->net_src.type == AT_IPv6 && pi->net_dst.type == AT_IPv6
+ && pi->ipproto == 6 ) {
+ /* TCP over IPv6 */
+ sprintf( buf,
+ "(ipv6.addr eq %s and ipv6.addr eq %s) and (tcp.port eq %d and tcp.port eq %d)",
+ ip6_to_str((const struct e_in6_addr *)pi->net_src.data),
+ ip6_to_str((const struct e_in6_addr *)pi->net_dst.data),
+ pi->srcport, pi->destport );
+ len = 16;
+ is_ipv6 = TRUE;
+ }
+ else {
+ g_free( buf );
+ return NULL;
+ }
+ memcpy(ip_address[0], pi->net_src.data, len);
+ memcpy(ip_address[1], pi->net_dst.data, len);
+ 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 gulong seq[2];
+static guint8 src_addr[2][MAX_IPADDR_LEN];
+static guint src_port[2] = { 0, 0 };
+
+void
+reassemble_tcp( gulong sequence, gulong length, const char* data,
+ gulong data_length, int synflag, address *net_src,
+ address *net_dst, guint srcport, guint dstport) {
+ guint8 srcx[MAX_IPADDR_LEN], dstx[MAX_IPADDR_LEN];
+ int src_index, j, first = 0, len;
+ gulong newseq;
+ tcp_frag *tmp_frag;
+ tcp_stream_chunk sc;
+
+ src_index = -1;
+
+ /* First, check if this packet should be processed. */
+
+ if ((net_src->type != AT_IPv4 && net_src->type != AT_IPv6) ||
+ (net_dst->type != AT_IPv4 && net_dst->type != AT_IPv6))
+ return;
+
+ if (net_src->type == AT_IPv4)
+ len = 4;
+ else
+ len = 16;
+
+ /* Now check if the packet is for this connection. */
+ memcpy(srcx, net_src->data, len);
+ memcpy(dstx, net_dst->data, len);
+ if (
+ ! (
+ memcmp(srcx, ip_address[0], len) == 0 &&
+ memcmp(dstx, ip_address[1], len) == 0 &&
+ srcport == tcp_port[0] &&
+ dstport == tcp_port[1]
+ ) &&
+ ! (
+ memcmp(srcx, ip_address[1], len) == 0 &&
+ memcmp(dstx, ip_address[0], len) == 0 &&
+ srcport == tcp_port[1] &&
+ dstport == tcp_port[0]
+ )
+ )
+ return;
+
+ /* Initialize our stream chunk. This data gets written to disk. */
+ memcpy(sc.src_addr, srcx, len);
+ sc.src_port = srcport;
+ sc.dlen = data_length;
+
+ /* Check to see if we have seen this source IP and port before.
+ (Yes, we have to check both source IP and port; the connection
+ might be between two different ports on the same machine.) */
+ for( j=0; j<2; j++ ) {
+ if (memcmp(src_addr[j], srcx, len) == 0 && src_port[j] == srcport ) {
+ 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_port[j] == 0 ) {
+ memcpy(src_addr[j], srcx, len);
+ src_port[j] = srcport;
+ 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( src_index, &sc, data );
+ 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] ) {
+ gulong 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;
+ }
+ sc.dlen = data_length;
+ 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( src_index, &sc, data );
+ }
+ /* done with the packet, see if it caused a fragment to fit */
+ while( check_fragments( src_index, &sc ) )
+ ;
+ }
+ else {
+ /* out of order packet */
+ if(data_length > 0 && sequence > seq[src_index] ) {
+ tmp_frag = (tcp_frag *)malloc( sizeof( tcp_frag ) );
+ tmp_frag->data = (guchar *)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_stream_chunk *sc ) {
+ 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 ) {
+ sc->dlen = current->data_len;
+ write_packet_data( index, sc, current->data );
+ }
+ 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;
+ memset(src_addr[i], '\0', MAX_IPADDR_LEN);
+ src_port[i] = 0;
+ memset(ip_address[i], '\0', MAX_IPADDR_LEN);
+ tcp_port[i] = 0;
+ bytes_written[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( int index, tcp_stream_chunk *sc, const char *data )
+{
+ fwrite( sc, 1, sizeof(tcp_stream_chunk), data_out_file );
+ fwrite( data, 1, sc->dlen, data_out_file );
+ bytes_written[index] += sc->dlen;
+}