Hello all,
attached is a patch for the sdp dissector.
It will add automatic detection of RTP and RTCP for Protocols using SDP
(e.g. SIP, MGCP, ...).
However, this is a first try and it might not work in some cases. I have
tested it only with a few SIP calls.
Best Regards,
Lars Roland
Index: ethereal/packet-sdp.c
===================================================================
RCS file: /cvsroot/ethereal/packet-sdp.c,v
retrieving revision 1.35
diff -u -r1.35 packet-sdp.c
--- ethereal/packet-sdp.c 14 Oct 2003 21:26:37 -0000 1.35
+++ ethereal/packet-sdp.c 17 Nov 2003 14:42:50 -0000
@@ -32,8 +32,12 @@
#include <glib.h>
#include <epan/packet.h>
+#include <epan/conversation.h>
#include <epan/strutil.h>
+static dissector_handle_t rtp_handle=NULL;
+static dissector_handle_t rtcp_handle=NULL;
+
static int proto_sdp = -1;
/* Top level fields */
@@ -137,6 +141,11 @@
static void dissect_sdp_media(tvbuff_t *tvb, proto_item *ti);
static void dissect_sdp_media_attribute(tvbuff_t *tvb, proto_item *ti);
+static char *media_port;
+static char *media_proto;
+static char *connection_address;
+static char *connection_type;
+
static void
dissect_sdp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{
@@ -153,6 +162,20 @@
int hf = -1;
char *string;
+ address src_addr;
+ conversation_t *conv=NULL;
+
+ guint32 ipv4_address=0;
+ guint32 ipv4_port=0;
+ gboolean is_rtp=FALSE;
+ gboolean is_ipv4_addr=FALSE;
+ struct in_addr ipaddr;
+
+ media_port=NULL;
+ media_proto=NULL;
+ connection_address=NULL;
+ connection_type=NULL;
+
/*
* As RFC 2327 says, "SDP is purely a format for session
* description - it does not incorporate a transport protocol,
@@ -289,6 +312,60 @@
offset = next_offset;
}
+
+ /* Now look, if we have strings collected.
+ * Try to convert ipv4 address and port into binary format,
+ * so we can use them to detect rtp and rtcp streams.
+ * Don't forget to free the strings!
+ */
+
+ if(media_port!=NULL) {
+ ipv4_port = atol(media_port);
+ g_free(media_port);
+ }
+ if(media_proto!=NULL) {
+ /* Check if media protocol is RTP */
+ is_rtp= !strcmp(media_proto,"RTP/AVP");
+ g_free(media_proto);
+ }
+ if(connection_address!=NULL) {
+ if(connection_type!=NULL && strcmp(connection_type,"IP4")==0 ) {
+ if(inet_aton(connection_address, &ipaddr) !=0 ) {
+ /* connection_address could be converted to a valid
ipv4 address*/
+ is_ipv4_addr=TRUE;
+ ipv4_address = ipaddr.s_addr;
+ }
+ }
+ g_free(connection_address);
+ }
+ if(connection_type!=NULL) {
+ g_free(connection_type);
+ }
+
+ /* Add rtp and rtcp conversation, if available */
+ if((!pinfo->fd->flags.visited) && ipv4_address!=0 && ipv4_port!=0 && is_rtp &&
is_ipv4_addr){
+ src_addr.type=AT_IPv4;
+ src_addr.len=4;
+ src_addr.data=(char *)&ipv4_address;
+
+ if(rtp_handle){
+ conv=find_conversation(&src_addr, &src_addr, PT_UDP,
ipv4_port, ipv4_port, NO_ADDR_B|NO_PORT_B);
+ if(!conv){
+ conv=conversation_new(&src_addr, &src_addr, PT_UDP,
ipv4_port, ipv4_port, NO_ADDR_B|NO_PORT_B);
+ conversation_set_dissector(conv, rtp_handle);
+ }
+ }
+
+ if(rtcp_handle){
+ ipv4_port++;
+ conv=find_conversation(&src_addr, &src_addr, PT_UDP,
ipv4_port, ipv4_port, NO_ADDR_B|NO_PORT_B);
+ if(!conv){
+ conv=conversation_new(&src_addr, &src_addr, PT_UDP,
ipv4_port, ipv4_port, NO_ADDR_B|NO_PORT_B);
+ conversation_set_dissector(conv, rtcp_handle);
+ }
+ }
+ }
+
datalen = tvb_length_remaining(tvb, offset);
if (datalen > 0) {
proto_tree_add_text(sdp_tree, tvb, offset, datalen,
@@ -414,6 +491,8 @@
if( next_offset == -1 )
return;
tokenlen = next_offset - offset;
+ /* Save connection address type */
+ connection_type = tvb_get_string(tvb, offset, tokenlen);
proto_tree_add_item(sdp_connection_info_tree,
hf_connection_info_address_type,tvb,
@@ -424,9 +503,14 @@
next_offset = tvb_find_guint8(tvb,offset,-1,'/');
if( next_offset == -1){
tokenlen = -1; /* end of tvbuff */
+ /* Save connection address */
+ connection_address = tvb_get_string(tvb, offset, tvb_length_remaining(tvb,
offset));
} else {
tokenlen = next_offset - offset;
+ /* Save connection address */
+ connection_address = tvb_get_string(tvb, offset, tokenlen);
}
+
proto_tree_add_item(sdp_connection_info_tree,
hf_connection_info_connection_address, tvb,
offset,tokenlen,FALSE);
@@ -667,6 +751,8 @@
if(next_offset != -1){
tokenlen = next_offset - offset;
+ /* Save port info */
+ media_port = tvb_get_string(tvb, offset, tokenlen);
proto_tree_add_item(sdp_media_tree, hf_media_port, tvb,
offset, tokenlen, FALSE);
@@ -684,6 +770,8 @@
if(next_offset == -1)
return;
tokenlen = next_offset - offset;
+ /* Save port info */
+ media_port = tvb_get_string(tvb, offset, tokenlen);
/* XXX Remember Port */
proto_tree_add_item(sdp_media_tree, hf_media_port, tvb,
@@ -697,6 +785,8 @@
return;
tokenlen = next_offset - offset;
+ /* Save port protocol */
+ media_proto = tvb_get_string(tvb, offset, tokenlen);
/* XXX Remember Protocol */
proto_tree_add_item(sdp_media_tree, hf_media_proto, tvb,
@@ -722,7 +812,7 @@
* We need to find out the address of the other side first and it
* looks like that info can be found in SIP headers only.
*/
-
+
}
static void dissect_sdp_media_attribute(tvbuff_t *tvb, proto_item * ti){
@@ -987,3 +1077,10 @@
*/
register_dissector("sdp", dissect_sdp, proto_sdp);
}
+
+void
+proto_reg_handoff_sdp(void)
+{
+ rtp_handle = find_dissector("rtp");
+ rtcp_handle = find_dissector("rtcp");
+}
\ No newline at end of file
