Re: RTP Muxing with compressed header

[Sourabh Rathor <sourabhrathor2008 () gmail com>]

Hi Anders,

Its not there in the makefile.
For RTP muxing with compressed header. I have made some changes to
packet-nb_rtpmux.c as shown:
****
Change 1. (In dissect_nb_rtpmux.c)
 if (rtpcompressdissector)
            {
                next_tvb = tvb_new_subset(tvb, offset+5,
                        MIN(tvb_length(tvb)-5-offset, length), length);

                call_dissector(rtpcompressdissector, next_tvb, pinfo,
nb_rtpmux_tree);
            }
            else
            {
                proto_tree_add_item(nb_rtpmux_tree,
                    hf_nb_rtpmux_data, tvb, offset+5, length == 0 ?
-1:length, FALSE);
            }
*****
Change 2.

void
proto_reg_handoff_nb_rtpmux(void)
{
    static gboolean inited = FALSE;

    if (!inited) {

        dissector_handle_t nb_rtpmux_handle;

/*  Use new_create_dissector_handle() to indicate that dissect_nb_rtpmux()
 *  returns the number of bytes it dissected (or 0 if it thinks the packet
 *  does not belong to PROTONAME).
 */
        nb_rtpmux_handle = new_create_dissector_handle(dissect_nb_rtpmux,
            proto_nb_rtpmux);

        dissector_add_handle("udp.port", nb_rtpmux_handle);
        rtpcompressdissector = find_dissector("compress_rtp");
        inited = TRUE;
    }

}

And also written a new dissector function for RTP packets with compresssed
headers as shown below:
static int
dissect_compress_rtp(tvbuff_t *tvb, packet_info *pinfo, proto_tree *tree)
{

/* Set up structures needed to add the protocol subtree and manage it */
       proto_item *ti;
       proto_tree *compress_rtp_tree;
/*Need to add some checks here.....(Heuristics)*/

/* Make entries in Protocol column and info column on summary display */
       col_set_str(pinfo->cinfo,COL_PROTOCOL,"Compress_RTP");

       if(tree) {
       unsigned int offset = 0;

/* Create displays subtree for the protocol */

       //while()

       guint16 timestamp, sequence_no;

       ti =
proto_tree_add_item(tree,proto_compress_rtp,tvb,offset,-1,FALSE);
       compress_rtp_tree = proto_item_add_subtree(ti,ett_compress_rtp);


proto_tree_add_item(compress_rtp_tree,hf_compress_rtp_sequence_no,tvb,offset,1,FALSE);
       timestamp = tvb_get_ntohs(tvb,offset);

proto_tree_add_uint(compress_rtp_tree,hf_compress_rtp_timestamp,tvb,offset+1,2,FALSE);

proto_tree_add_item(compress_rtp_tree,hf_compress_rtp_data,tvb,offset+3,-1,FALSE);

       return tvb_length(tvb);
}


Any feedback for the same.

Thanks
Sourabh Rathor
On Wed, Feb 10, 2010 at 4:58 PM, Anders Broman
<anders.broman () ericsson com>wrote:

>  Hi,
> ??? It's in the makefile, in my SVN tree, on the server...
> Are youi doing svn co http://anonsvn.wireshark.org/wireshark/trunk/wireshark ?
>
> /Anders
>
>  ------------------------------
> *From:* wireshark-dev-bounces () wireshark org [mailto:
> wireshark-dev-bounces () wireshark org] *On Behalf Of *Sourabh Rathor
> *Sent:* den 10 februari 2010 09:22
> *To:* Developer support list for Wireshark
> *Subject:* Re: [Wireshark-dev] RTP Muxing with compressed header
>
> Hi Anders,
>
> Thanks for your input. This file is not visible now in the latest trunks
> and in the trunks before. Is it removed ?
> Does it support the compression or just the muxing functionality ?
>
> Thanks In advance
> Sourabh Rathor
>
> On Wed, Feb 10, 2010 at 10:56 AM, Anders Broman <a.broman () telia com>wrote:
>
> >  Hi,
> >
> > There is a basic dissector to expand on, packet-nb_rtpmux.c.
> >
> > Regards
> >
> > Anders
> >
> >
> >  ------------------------------
> >
> > *Från:* wireshark-dev-bounces () wireshark org [mailto:
> > wireshark-dev-bounces () wireshark org] *För *Sourabh Rathor
> > *Skickat:* den 10 februari 2010 05:43
> > *Till:* wireshark-dev () wireshark org
> > *Ämne:* [Wireshark-dev] RTP Muxing with compressed header
> >
> >
> >
> >
> > Hi
> >
> > I am actually looking or designing a new dissector function for decoding
> > RTP MUXed streams with compressed headers. This is compliant to 3GPP TS
> > 29.414. Need some inputs to start working on the same. Please reply if any
> > body has any pointers for it.
> >
> >
> > Thanks
> > Sourabh Rathor
> >
> >
> > ___________________________________________________________________________
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>
>
>
> --
> Sourabh Rathor
> Institute Of Informatics & Communication
> South Campus, Delhi University
>
> ___________________________________________________________________________
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-- 
Sourabh Rathor
Institute Of Informatics & Communication
South Campus, Delhi University

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