Re: Sometimes SLL/Linux cooked-mode capture is decoded and sometimes its not (difference between two packets?)

[Michael Lum <michael.lum () starsolutions com>]

Sorry, for the late reply/thanks Pascal.

My capture tool needed to look at the datalink type from libpcap in order to encode the "fake" syslog correctly.

I wondered why when I first added this feature that it seemed like sometimes it would work and sometimes it wouldn't.

As you would know it was because the datalink type was changing depending on what interface I was capturing
and the encapsulation has to be formatted differently.

I now have ethernet, Linux cooked capture, and NFLOG working.

Thanks again!

BR,

Michael Lum

________________________________
From: Wireshark-dev [mailto:wireshark-dev-bounces () wireshark org] On Behalf Of Pascal Quantin
Sent: June-07-18 2:40 PM
To: Developer support list for Wireshark
Subject: Re: [Wireshark-dev] Sometimes SLL/Linux cooked-mode capture is decoded and sometimes its not (difference 
between two packets?)

Hi Michael,

Le jeu. 7 juin 2018 à 23:32, Michael Lum <michael.lum () starsolutions com<mailto:michael.lum () starsolutions com>> a 
écrit :
Hi,

I've attached two captures with a single packet in each.

They are both supposed to be syslog events injected into the capture with SLL (Linux cooked capture).

On one everthing is decoded as expected in the other with the same first 16 octets it is detected as
Ethernet II only.

I cannot figure out why they are not both decoded as SLL/Linux cooked-mode captures.

Any thoughts would be greatly appreciated.

I'm running on Windows 7 using Wireshark 2.6.1.
The capture was taken on a CentOs 7 box by a tool injecting the "fake" syslog message.

This comes from the encapsulation type stored in the pcap file: one is using 25 (Linux coooked capture) while the other 
one is using 1 (ethernet). So something is wrong with the tool used to capture the second pcap.
You can fix the file with the following command: editcap -T linux-sll sll-not_detected.pcap sll-not_detected_fixed.pcap

Best regards,
Pascal.

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