Robert Naumann wrote:
> Hello,
>
> i have got a new problem with tcp_dissect_pdus(). I got a PDU with the 
> fixed header lenght of 8 Bytes, which also contains the lenght of the 
> whole PDU.  The lenght-information is stored in the 3th Byte, so the 
> minimum Headersize is 3.  The Datalength of the PDU in my cases is 
> always 1 Byte.
>
> In the first case the PDU is split over 4 TCP-Segments:
>
> 1. Segment: 1 Byte (PDU Type)
> 2. Segment: 1 Byte (some stuff)
> 3. Segment: 1 Byte (length-information)
> 4. Segment: 5 Bytes (some stuff + one Databyte)
>
> - in this case tcp_dissect_pdus(tvb, pinfo, tree, TRUE, 3 , 
> get_pdu_len, dissect_pdus);  works fine
> -> get_pdu_len passes 9 as the number of Bytes for the whole PDU
> -> reassembling works followed by a correct dissection
>
> In the second case the PDU is only slip over 2 TCP-Segments:
>
> 1. Segment: 1 Byte (PDU Type)
> 2. Segment: 8 Bytes (some stuff + length information + some stuff + 
> Databyte)
>
> - in this case tcp_dissect_pdus(tvb, pinfo, tree, TRUE, 3 , 
> get_pdu_len, dissect_pdus);  doesnt work correctly
> -> get_pdu_len passes 9 as the number of Bytes for the whole PDU
> -> the wireshark-frame only shows [TCP segment of a reassembled PDU] 
> with reassembled 3 Bytes (minimum Headerbytes)
> -> the rest seems to be ignored, which causes wrong dissection of the 
> following packets in the same direction
>
> I already looked in packet-tcp.c and tried to figure out whats 
> happening. tcp_dissect_pdus() seems to work correctly. I think the 
> problem lies in desegment_tcp() but i couldn't figure out whats wrong.
>
> Any help would be appreciated.
> Regards,
>
> Robert
>
No answer? Noone ever had a similar problem? I wanna know if this could 
be a bug in desegment_tcp()-code or if i'm doing something wrong. This 
different (wrong) reassembling and dissection only caused by different 
splitting over  TCP-Segments makes no sense. My Dissectorcode didnt change.

Hopefully awaiting any reply,

Regards
Robert

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