Bug #77807 for Net-Pcap: Net-Pcap loop will not work correctly in a multi-threaded environment

Wed Jun 13 16:41:40 2012 mike.schmidt [...] intello.com - Ticket created

Subject:	Net-Pcap loop will not work correctly in a multi-threaded environment
Date:	Wed, 13 Jun 2012 16:41:10 -0400
To:	bug-Net-Pcap [...] rt.cpan.org
From:	Mike Schmidt <mike.schmidt [...] intello.com>

I have been trying to use Net::Pcap's loop function (cia Net::PcapUtuls) in a multithreaded environment where I need to monitor about 15-20 interfaces. It did not work correctly, in that only one callback routine was ever called, no matter what the interface was. This is, I presume, what you meant in the Limitations section of the Net::Pcap docs. Is this a limit imposed by Net::Pcap? In the libpcap documentation, they certainly imply that multithreade use is possible, even expected. If this is a Net::Pcap limit, is it easy to change? -- *Mike SCHMIDT **CTO Intello Technologies Inc. **mike.schmidt@intello.com* *Canada: 1-888-404-6261 x320 USA: 1-888-404-6268 x320 Mobile: 514-409-6898 www.intello.com* * *

Wed Nov 28 18:09:08 2012 SAPER [...] cpan.org - Correspondence added

Subject:	Re: [rt.cpan.org #77807] Net-Pcap loop will not work correctly in a multi-threaded environment
Date:	Thu, 29 Nov 2012 00:08:52 +0100
To:	bug-Net-Pcap [...] rt.cpan.org
From:	Sébastien Aperghis-Tramoni <saper [...] cpan.org>

Mike Schmidt wrote via RT: Show quoted text

> I have been trying to use Net::Pcap's loop function (cia Net::PcapUtuls) in > a multithreaded environment where I need to monitor about 15-20 interfaces. > It did not work correctly, in that only one callback routine was ever > called, no matter what the interface was. This is, I presume, what you > meant in the Limitations section of the Net::Pcap docs. Is this a limit > imposed by Net::Pcap? In the libpcap documentation, they certainly imply > that multithreade use is possible, even expected. > If this is a Net::Pcap limit, is it easy to change?

This is a limit in Net::Pcap itself and not in libpcap. The origin of the problem, as described in the documentation, is that the callback function is stored in a global variable in Pcap.xs » https://github.com/maddingue/Net-Pcap/blob/master/Pcap.xs#L52 A solution would be to wrap the pcap_t object in a Net::Pcap object so each Perl callback can be attached to the corresponding pcap object. It's not necessarily hard, but it takes a bit of time and C knowledge to do correctly. -- Sébastien Aperghis-Tramoni Close the world, txEn eht nepO.

Wed Nov 28 18:09:09 2012 The RT System itself - Status changed from 'new' to 'open'

Sun May 15 09:46:13 2016 SAPER [...] cpan.org - Correspondence added

James Rouzier found a way to remove this limitation. This should be fixed with version 0.18. Details in: https://github.com/maddingue/Net-Pcap/pull/5 -- Close the world, txEn eht nepO.

Mon May 16 09:03:23 2016 SAPER [...] cpan.org - Status changed from 'open' to 'resolved'

Mon May 16 09:03:23 2016 SAPER [...] cpan.org - Fixed in 0.18 added