Snort mailing list archives
Re: var PKT_TIMEOUT in sfdaq.c
From: Russ Combs <rcombs () sourcefire com>
Date: Wed, 29 Feb 2012 18:05:33 -0500
You should post your question on snort-users or wherever the PFRING DAQ is supported. On Wed, Feb 29, 2012 at 6:01 PM, Guillaume Daleux < guillaume.daleux () abovesecurity com> wrote:
Hi,**** ** ** Thanks for your answer, I understand why you used a positive timeout with Idle functions.**** ** ** We use snort 2.9.2.1 with daq 0.6.2 and pfring daq module. I spoke about heisenbug bug because the problem arrived just when we launched snort with svc program and it stopped when we printed a debug line in pfring daq module.**** ** ** Thanks**** Guillaume DALEUX**** ** ** ** ** *From:* Russ Combs [mailto:rcombs () sourcefire com] *Sent:* Wednesday, February 29, 2012 5:29 PM *To:* Michael Altizer *Cc:* snort-devel () lists sourceforge net *Subject:* Re: [Snort-devel] var PKT_TIMEOUT in sfdaq.c**** ** ** ** ** On Wed, Feb 29, 2012 at 5:22 PM, Michael Altizer <maltizer () sourcefire com> wrote:**** On 02/29/2012 05:00 PM, Guillaume Daleux wrote: **** Hi all,**** **** We had some problems with snort and snort daq which use 100% of processing power. After debugging, we saw that our system had a lot of call to poll function.**** **** The function poll (call in daq) set with a default snort parameter (PKT_TIMEOUT = 1000) is called everytime and didn't respect this timeout of 1 second (maybe heisenbug because only one printf removed this problem).** ** **** We want to ask you, why this parameter is set to 1000 ms and not -1 ? The poll function is called to wait packets so why the snort daq uses a timeout and not directly value -1 which would block until a packet arrive ?**** **** Can we patch snort and change PKT_TIMEOUT to -1 ?**** **** **** Thanks for your answer.**** **** **** ** ** Snort does certain "idle work" (see snort.c:SnortIdle()) each time the DAQ acquire call returns. If you made the call fully blocking, it would only return in the case of an error/signal/breakloop, and that code would not execute [often enough] when the packet rate is too low. I do not know why the timeout was being ignored in your case, which seems to be the real issue. You have not mentioned which DAQ module you are using.**** ** ** If you are mucking about in the code, it would help to know what the call to poll() is returning as well. **** ------------------------------------------------------------------------------ Virtualization & Cloud Management Using Capacity Planning Cloud computing makes use of virtualization - but cloud computing also focuses on allowing computing to be delivered as a service. http://www.accelacomm.com/jaw/sfnl/114/51521223/ _______________________________________________ Snort-devel mailing list Snort-devel () lists sourceforge net https://lists.sourceforge.net/lists/listinfo/snort-devel Please visit http://blog.snort.org for the latest news about Snort!**** ** **
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Current thread:
- Re: Invalid protocol name for "ip_proto" rule option: "igmp" Lukas Matt (Feb 24)
- Re: Invalid protocol name for "ip_proto" rule option: "igmp" Joel Esler (Feb 24)
- var PKT_TIMEOUT in sfdaq.c Guillaume Daleux (Feb 29)
- Re: var PKT_TIMEOUT in sfdaq.c Michael Altizer (Feb 29)
- Re: var PKT_TIMEOUT in sfdaq.c Russ Combs (Feb 29)
- Re: var PKT_TIMEOUT in sfdaq.c Guillaume Daleux (Feb 29)
- Re: var PKT_TIMEOUT in sfdaq.c Russ Combs (Feb 29)
- var PKT_TIMEOUT in sfdaq.c Guillaume Daleux (Feb 29)
- Re: Invalid protocol name for "ip_proto" rule option: "igmp" Joel Esler (Feb 24)