Wireshark-dev: Re: [Wireshark-dev] Cannot get external capture (extcap) interface to work with
From: Roland Knall <rknall@xxxxxxxxx>
Date: Sun, 30 Dec 2018 18:18:27 +0100
Hi

Have you properly closed the pipe after sending the packets? It looks more like an issue in flushing the pipe, then a code error. tshark handles this a little bit different then wireshark, so that might be the reason, why it did work on the CLI. 

Try flushing the pipe immediately after every packet. Otherwise, without the code nothing much can be said.

kind regards
Roland

Am So., 30. Dez. 2018 um 17:39 Uhr schrieb hdv <henri.de.veer@xxxxxxxxx>:

Hello,

I'm developing a new extcap interface as described in chapter 8.2.1 of the developers guide. The goal is to implement a plugin so I can directly attach it to a CAN bus sniffing device called "AnaGate CAN" (see http://www.anagate.de/)

Until now all went well, I can see my new interface in the main wireshark window, select it, all choose all options etc.

I just implemented 2 dummy packets in my plugin before I continue to access the real target hardware (to avoid the hassle of setting up a working CAN network). The intention is to check if the interface is correct between my program and the main wireshark code.

When running my capture interface as follow:

extcap\anagate.exe  --host=192.168.2.51 --port=5001 --fifo=myfifo --capture

I nicely get a file (in libpcap format)  "myfifo" with a header and 2 CAN bus packets, which I can open in wireshark and show me the correct content.  (See attached file)

But when I start the capture from wireshark itself no packets are shown and no errors at all. The status bar says "Life capture in progress" and at the right "No Packets".

When running it via tshark with: tshark -i 4   It does return the 2 packets. So that is weird.

P.S. The random packet generator plugin does work, so the core wireshark code does not look broken.

So what is going on here? Any pointers on how to debug this in the core wireshark code.

Can anyone give me an advice how to proceed?

Thanks,

Henri


Wireshark version build:

Version 2.9.0 (v2.9.0rc0-990-g27a1906c)

Copyright 1998-2018 Gerald Combs <gerald@xxxxxxxxxxxxx> and contributors. License GPLv2+: GNU GPL version 2 or later <http://www.gnu.org/licenses/old-licenses/gpl-2.0.html> 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 (64-bit) with Qt 5.11.1, with WinPcap (4_1_3), with GLib 2.52.2, with zlib 1.2.11, with SMI 0.4.8, with c-ares 1.14.0, with Lua 5.2.4, with GnuTLS 3.4.11, with Gcrypt 1.7.6, with MIT Kerberos, with MaxMind DB resolver, with nghttp2 1.14.0, with LZ4, with Snappy, with libxml2 2.9.4, with QtMultimedia, with AirPcap, with SBC, with SpanDSP, with bcg729.

Running on 64-bit Windows 8.1, build 9600, with Intel(R) Core(TM) i7-3632QM CPU @ 2.20GHz (with SSE4.2), with 8084 MB of physical memory, with locale Dutch_Netherlands.1252, with WinPcap version 4.1.3 (packet.dll version 4.1.0.2980), based on libpcap version 1.0 branch 1_0_rel0b (20091008), with GnuTLS 3.4.11, with Gcrypt 1.7.6, with AirPcap 4.1.0 build 1622, binary plugins supported (14 loaded). Built using Microsoft Visual C++ 14.0 build 24215


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