tcpdump mailing list archives
Re: Problem with generation of Pcap traces for Wireshark through Libpcap
From: Guy Harris <guy () alum mit edu>
Date: Wed, 13 May 2009 12:52:32 -0700
On May 13, 2009, at 11:38 AM, Johan Mazel wrote:
My program work like this:-I initialize my process of capture on my network interface (eth0) through these 2 functions : pcap_create, pcap_activate (I also use some function like pcap_set_timeout, pcap_set_direction but this is not really relevant). -I initialize my process of writing into the file through these 2 functions: pcap_create, pcap_dump_open.
Umm, why are you calling pcap_create twice()? pcap_dump_open() creates the dump file for you; it does require a pcap_t as an argument, but that doesn't mean "just randomly open a pcap_t", it means "the packets you're writing are presumably coming from a live capture or another savefile, so you should supply the pcap_t for the live capture or savefile".
I.e., don't call pcap_create() twice; just pass the pcap_t for eth0, after you've activated it, to pcap_dump_open().
I'll fix pcap_dump_open() to fail if it's handed a non-activated pcap_t, as the reason why it needs a pcap_t is to get a link type value and snapshot length, and, until a live-capture pcap_t is activated, it doesn't have a link type value or snapshot length, so the link type for the dump file will be bogus.
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Current thread:
- Problem with generation of Pcap traces for Wireshark through Libpcap Johan Mazel (May 13)
- Re: Problem with generation of Pcap traces for Wireshark through Libpcap Guy Harris (May 13)
- Re: Problem with generation of Pcap traces for Johan Mazel (May 13)
- Re: Problem with generation of Pcap traces for Guy Harris (May 15)
- Re: Problem with generation of Pcap traces for Johan Mazel (May 16)
- Re: Problem with generation of Pcap traces for Guy Harris (May 16)
- Re: Problem with generation of Pcap traces for Johan Mazel (May 16)
- Re: Problem with generation of Pcap traces for Guy Harris (May 16)
- Re: Problem with generation of Pcap traces for Johan Mazel (May 17)
- Re: Problem with generation of Pcap traces for Johan Mazel (May 13)
- Re: Problem with generation of Pcap traces for Aaron Turner (May 16)
- Re: Problem with generation of Pcap traces for Wireshark through Libpcap Guy Harris (May 13)