Wireshark-dev: Re: [Wireshark-dev] DESEGMENT_ONE_MORE_SEGMENT usage/fault
From: wsgd <[email protected]>
Date: Mon, 22 Mar 2010 20:32:50 +0100
Are you above TCP ?
Inside Wireshark,
verify that "Edit / Preferences / Protocols / TCP / Allow subdissector to reassemble TCP streams"
is checked.


Lajos Oláh a écrit :
Hi all,
I'm developing a dissector dissecting MTP2 packets from RTP stream (for semipermanent connections). I used part of the code from packet-lapd.c (it is almost tha same except that it is for the LAPD protocol). In that code, when the RTP data ends in the middle of an MTP2 packet, the dissector sets pinfo->desegment_offset = 0 and pinfo->desegment_len = DESEGMENT_ONE_MORE_SEGMENT and exits. In the README.developer, it is written that if a dissector sets these values and returns it will be called again with data from the actual packet plus the data from the next packet. But this never happens. My dissector is never called with more data than 1 RTP data filed (40 byte in my case). I've also created debug patches for the TELNET dissector (packet-telnet.c) (to test this defregmentation functionality outside my buggy code) to force the dissector to always request data from the next packet using DESEGMENT_ONE_MORE_SEGMENT but it was failing as well. Have anyone of You encountered such problem? Am I doing something wrong? Do I need to do something extra to get this feature work or we have a wireshark bug? Please share experiences with these defregmentation method. (I've attached my code with debug printing included) Thanks.

*System Test Engineer*

Ericsson Telecom Hungary
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1017, Hungary
Phone +36309537333
[email protected]

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