Wireshark · Ethereal-dev: Re: [Ethereal-dev] T.38 decode with RTP

[Alejandro Vaquero <alejandrovaquero@xxxxxxxxx>]

Hi All, find attached a patch to add t38 setup info for h245 packets.

Regards
Alejandro

Alejandro Vaquero wrote:
> Hi Thomas,
>     that is because we only support t38 conversation setup on SDP 
> sessions (SIP or MGCP for example), and not in h245 used in h323. When 
> time permits, will add this for h245.
>
> Alejandro
>
> Thomas Sillaber wrote:
> > Hola Alejandro,
> >
> > thanks for the t30 patch => cool !
> >
> >  
> > >     What is the "method" you are talking about? is that "Decode 
> > > as.."? also can you provide the capture?
> > >     
> >
> >
> > When setting up a voip fax call the first packets (ced tone) are sent 
> > via
> > rtp . Then the actual channel is closed and reopend as t.38. ethereal
> > decodes the rtp packets right, but the t.38 packets are decoded as 
> > unkown
> > rtp verion 0.
> > To troubleshoot t.38 issues it will be cool to see the t.38 packets 
> > as t.38
> > protokoll and not as rtp version 0 packets (unknown packets)!!
> >
> > Attached is a sample t.38 capture
> >
> >
> > Thanks
> >
> > Thomas
> >
> >
> >
> >
> >
> >   
> > ------------------------------------------------------------------------
> >
> > _______________________________________________
> > Ethereal-dev mailing list
> > Ethereal-dev@xxxxxxxxxxxx
> > http://www.ethereal.com/mailman/listinfo/ethereal-dev
> >   
>
> _______________________________________________
> Ethereal-dev mailing list
> Ethereal-dev@xxxxxxxxxxxx
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Index: asn1/h245/packet-h245-template.c
===================================================================
--- asn1/h245/packet-h245-template.c	(revision 17033)
+++ asn1/h245/packet-h245-template.c	(working copy)
@@ -52,6 +52,7 @@
 #include <epan/emem.h>
 #include "packet-rtp.h"
 #include "packet-rtcp.h"
+#include "packet-t38.h"
 #include "packet-ber.h"
 #include <epan/emem.h>
 
@@ -61,6 +62,7 @@
 
 static dissector_handle_t rtp_handle=NULL;
 static dissector_handle_t rtcp_handle=NULL;
+static dissector_handle_t t38_handle=NULL;
 static dissector_table_t nsp_object_dissector_table;
 static dissector_table_t nsp_h221_dissector_table;
 static dissector_handle_t nsp_handle;
@@ -403,6 +405,7 @@
 void proto_reg_handoff_h245(void) {
 	rtp_handle = find_dissector("rtp");
 	rtcp_handle = find_dissector("rtcp");
+	t38_handle = find_dissector("t38");
 	data_handle = find_dissector("data");
 	h263_handle = find_dissector("h263data");
 	amr_handle = find_dissector("amr_if2");
Index: asn1/h245/h245.cnf
===================================================================
--- asn1/h245/h245.cnf	(revision 17033)
+++ asn1/h245/h245.cnf	(working copy)
@@ -576,25 +576,38 @@
 #----------------------------------------------------------------------------------------
 #.FN_FTR OpenLogicalChannelAck/forwardMultiplexAckParameters
 	
-	if((!pinfo->fd->flags.visited) && ipv4_address!=0 && ipv4_port!=0 && rtp_handle){
-		address src_addr;
+	if (!pinfo->fd->flags.visited) {
+		if (codec_type && strcmp(codec_type, "t38fax")==0) {
+			if(ipv4_address!=0 && ipv4_port!=0 && t38_handle){
+				address src_addr;
 
-		src_addr.type=AT_IPv4;
-		src_addr.len=4;
-		src_addr.data=(guint8*)&ipv4_address;
+				src_addr.type=AT_IPv4;
+				src_addr.len=4;
+				src_addr.data=(guint8*)&ipv4_address;
 
-		rtp_add_address(pinfo, &src_addr, ipv4_port, 0, "H245", pinfo->fd->num, NULL);
-	}
-	if((!pinfo->fd->flags.visited) && rtcp_ipv4_address!=0 && rtcp_ipv4_port!=0 && rtcp_handle){
-		address src_addr;
+				t38_add_address(pinfo, &src_addr, ipv4_port, 0, "H245", pinfo->fd->num);
+			}
+		} else {
+			if(ipv4_address!=0 && ipv4_port!=0 && rtp_handle){
+				address src_addr;
 
-		src_addr.type=AT_IPv4;
-		src_addr.len=4;
-		src_addr.data=(guint8*)&rtcp_ipv4_address;
+				src_addr.type=AT_IPv4;
+				src_addr.len=4;
+				src_addr.data=(guint8*)&ipv4_address;
 
-		rtcp_add_address(pinfo, &src_addr, rtcp_ipv4_port, 0, "H245", pinfo->fd->num);
+				rtp_add_address(pinfo, &src_addr, ipv4_port, 0, "H245", pinfo->fd->num, NULL);
+			}
+			if(rtcp_ipv4_address!=0 && rtcp_ipv4_port!=0 && rtcp_handle){
+				address src_addr;
+
+				src_addr.type=AT_IPv4;
+				src_addr.len=4;
+				src_addr.data=(guint8*)&rtcp_ipv4_address;
+
+				rtcp_add_address(pinfo, &src_addr, rtcp_ipv4_port, 0, "H245", pinfo->fd->num);
+			}
+		}
 	}
-
 #.END
 #----------------------------------------------------------------------------------------
 #.FN_HDR OpenLogicalChannel/reverseLogicalChannelParameters/multiplexParameters
@@ -606,25 +619,39 @@
 #.END
 #----------------------------------------------------------------------------------------
 #.FN_FTR OpenLogicalChannel/reverseLogicalChannelParameters/multiplexParameters
-	if((!pinfo->fd->flags.visited) && ipv4_address!=0 && ipv4_port!=0 && rtp_handle){
-		address src_addr;
+	
+	if (!pinfo->fd->flags.visited) {
+		if (codec_type && (strcmp(codec_type, "t38fax")==0)) {
+			if(ipv4_address!=0 && ipv4_port!=0 && t38_handle){
+				address src_addr;
 
-		src_addr.type=AT_IPv4;
-		src_addr.len=4;
-		src_addr.data=(guint8*)&ipv4_address;
+				src_addr.type=AT_IPv4;
+				src_addr.len=4;
+				src_addr.data=(guint8*)&ipv4_address;
 
-		rtp_add_address(pinfo, &src_addr, ipv4_port, 0, "H245", pinfo->fd->num, NULL);
-	}
-	if((!pinfo->fd->flags.visited) && rtcp_ipv4_address!=0 && rtcp_ipv4_port!=0 && rtcp_handle){
-		address src_addr;
+				t38_add_address(pinfo, &src_addr, ipv4_port, 0, "H245", pinfo->fd->num);
+			}
+		} else {
+			if(ipv4_address!=0 && ipv4_port!=0 && rtp_handle){
+				address src_addr;
 
-		src_addr.type=AT_IPv4;
-		src_addr.len=4;
-		src_addr.data=(guint8*)&rtcp_ipv4_address;
+				src_addr.type=AT_IPv4;
+				src_addr.len=4;
+				src_addr.data=(guint8*)&ipv4_address;
 
-		rtcp_add_address(pinfo, &src_addr, rtcp_ipv4_port, 0, "H245", pinfo->fd->num);
+				rtp_add_address(pinfo, &src_addr, ipv4_port, 0, "H245", pinfo->fd->num, NULL);
+			}
+			if(rtcp_ipv4_address!=0 && rtcp_ipv4_port!=0 && rtcp_handle){
+				address src_addr;
+
+				src_addr.type=AT_IPv4;
+				src_addr.len=4;
+				src_addr.data=(guint8*)&rtcp_ipv4_address;
+
+				rtcp_add_address(pinfo, &src_addr, rtcp_ipv4_port, 0, "H245", pinfo->fd->num);
+			}
+		}
 	}
-
 #.END
 
 #--- NonStandardParameter ---------------------------------------------------------------