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Wireshark-bugs: [Wireshark-bugs] [Bug 5235] New: tcp.len (TCP Segment Len) is smaller than shoul

Date: Sat, 18 Sep 2010 06:28:47 -0700 (PDT)
https://bugs.wireshark.org/bugzilla/show_bug.cgi?id=5235

           Summary: tcp.len (TCP Segment Len) is smaller than should be
           Product: Wireshark
           Version: 1.5.x (Experimental)
          Platform: x86-64
        OS/Version: Windows 7
            Status: NEW
          Severity: Minor
          Priority: Low
         Component: TShark
        AssignedTo: wireshark-bugs@xxxxxxxxxxxxx
        ReportedBy: boaz.brickner@xxxxxxxxx


Created an attachment (id=5176)
 --> (https://bugs.wireshark.org/bugzilla/attachment.cgi?id=5176)
A packet example pcap file with the descripted problem

Build Information:
Version 1.5.0-SVN-34080 (SVN Rev 34080 from /trunk)

Copyright 1998-2010 Gerald Combs <gerald@xxxxxxxxxxxxx> and contributors.
This is free software; see the source for copying conditions. There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

Compiled with GTK+ 2.16.6, (64-bit) with GLib 2.22.4, with WinPcap (version
unknown), with libz 1.2.3, without POSIX capabilities, without libpcre, without
SMI, with c-ares 1.7.1, with Lua 5.1, without Python, with GnuTLS 2.8.5, with
Gcrypt 1.4.5, without Kerberos, with GeoIP, with PortAudio V19-devel (built Sep 
8 2010), with AirPcap.

Running on 64-bit Windows 7, build 7600, with WinPcap version 4.1.2 (packet.dll
version 4.1.0.2001), based on libpcap version 1.0 branch 1_0_rel0b (20091008),
GnuTLS 2.8.5, Gcrypt 1.4.5, without AirPcap.

Built using Microsoft Visual C++ 9.0 build 30729

Wireshark is Open Source Software released under the GNU General Public
License.

Check the man page and http://www.wireshark.org for more information.
--
Hi.

While testing Pcap.Net (http://pcapdot.net), I've found this bug in tshark:

I use tshark on a pcap file using these arguments:
-o udp.check_checksum:TRUE 
-o tcp.relative_sequence_numbers:FALSE 
-o tcp.analyze_sequence_numbers:FALSE 
-o tcp.track_bytes_in_flight:FALSE 
-o tcp.desegment_tcp_streams:FALSE 
-o tcp.check_checksum:TRUE 
-o ttp.dechunk_body:FALSE                                                      
  -t r -n -r "filename.pcap" -T pdml

The pdml file I get for specific packets has a smaller tcp.len than what I
expect.

In the attached pcap file there is one packet that if opened by Wireshark we
can see that the TCP layer takes 16 bytes.
However, when I run tshark on it I get a pdml file with tcp.len of 12 bytes.

Thank you,

Boaz.

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