Wireshark-dev: Re: [Wireshark-dev] tshark: drop features "dump to stdout" and "read filter" - c
From: "Jim Young" <[email protected]>
Date: Wed, 10 Oct 2007 13:40:44 -0400
Hello All,

>>> Ulf Lamping <[email protected]> 10/10/07 11:29 AM >>>
> > The "temporary file model" is working in Wiresharks "update list of 
> > packets" mode for quite a while and is working ok.
> 

When doing a "live capture" in Wireshark on Windows 
platforms I've really come to depend on dumpcap to 
create and write the temporary trace files 
(the $TEMP/etherXXXX* files).

With the current "temporary file model" by the time 
Wireshark sees the data dumpcap has already 
committed the packets to disk.

We've had several occasions where Wireshark crashed 
while in the middle of a "live capture".   With dumpcap 
building the actual trace files, I was able to open the 
orphaned etherXXXX* files and recover the trace
data.  In some cases I was able to determine that
a specific packet or set of packets triggered the 
initial Wireshark crash.   

These triggered Wireshark crashes have occurred 
because of a defect in a dissector.  Dumpcap doesn't 
have to concern itself with dissecting so is virtually 
immune to this type of crash.  

I'm not certain that these "trigger" packets would be 
recoverable if dumpcap simply forwarded the pcap data 
stream onto tshark and/or wireshark using a pipeline.  

FWIW:

I really like dumpcap's lean and mean design.  When I
really need to fetch the most data with as little packet 
drops as possible I use dumpcap (often with a snaplen
of 70 bytes or so).

Regards,

Jim Young