Wireshark-bugs: [Wireshark-bugs] [Bug 2200] New: Delays in packet capture on Windows with named
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From: bugzilla-daemon@xxxxxxxxxxxxx
Date: Wed, 16 Jan 2008 01:04:12 +0000 (GMT)
http://bugs.wireshark.org/bugzilla/show_bug.cgi?id=2200

           Summary: Delays in packet capture on Windows with named pipes
           Product: Wireshark
           Version: 0.99.6
          Platform: PC
        OS/Version: Windows XP
            Status: NEW
          Severity: Major
          Priority: High
         Component: Wireshark
        AssignedTo: wireshark-bugs@xxxxxxxxxxxxx
        ReportedBy: benjamin_tse@xxxxxxxxxxx


Build Information:
Version 0.99.6a (SVN Rev 22276)

Copyright 1998-2007 Gerald Combs <[EMAIL PROTECTED]> 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+ 2.10.12, with GLib 2.12.12, with WinPcap (version unknown),
with libz 1.2.3, with libpcre 6.4, with Net-SNMP 5.4, with ADNS, with Lua 5.1,
with GnuTLS 1.6.1, with Gcrypt 1.2.3, with MIT Kerberos, with PortAudio
PortAudio V19-devel, with AirPcap.

Running on Windows XP Service Pack 2, build 2600, with WinPcap version 4.1 beta
(packet.dll version 4.1.0.902), based on libpcap version 0.9.6 branch, with
AirPcap 3.0.0 build 954.

Built using Microsoft Visual C++ 6.0 build 8804
--
Bug 1181 still happens on Windows machines when capturing from a named pipe.

I've created a new bug rather than reopening 1181 as the scope is constrained
somewhat more.

Basically, when capturing from a named pipe the wireshark display lags by one
packet. This is especially frustrating when the packets arrive at low rates.

tshark is fine. But the packet count in dumpcap also lags by one.

Looking at the code, the problem appears to be in cap_pipe_select(). It
attempts to use WaitForSingleObject() on the named pipe but AFAICT this never
blocks.

I've attached a diff for some code that fixes the issue for me. The semantics
of overlapped IO in Win32 is quite different from the select/read model - hence
the other changes!

I've tested this fix on WinXP, 2k server and 2003 server. I've also checked
that my changes compile on a Freespire box that I have lying around.


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