Mailing List Archive: ClamAV: devel

Patch: add jitter to freshclam's update period

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npjohnso at cs

Aug 22, 2012, 9:08 AM

Post #1 of 3 (742 views)
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Patch: add jitter to freshclam's update period

Hello,

If you are managing a large number of machines, jitter helps spread
freshclam's network traffic over time so the machines don't all hit
the network simultaneously.

Here is a patch to add jitter to freshclam's update period. It adds a
random number of seconds in [0, jitter) to the bigsleep. It adds a
configuration option "Jitter" (-j, --jitter) to freshclam. The
default value is zero seconds, which will cause no change to most
users.

Thank you,
N

$ diff -w clamav-0.97.5-original/freshclam/freshclam.c
clamav-0.97.5/freshclam/freshclam.c
156a157
> mprintf(" --jitter=#n -j #n random jitter on check period, in seconds\n");
244a246,248
> /* Seed random number generator (for Jitter) */
> srand(time(0));
>
429a434
> int jitter;
455a461,467
> jitter = optget(opts, "Jitter")->numarg;
> if( jitter < 0 ) {
> logg("^Jitter must be a non-negative integer number of seconds.");
> optfree(opts);
> return 41;
> }
>
501a514,516
> if( jitter > 0 )
> sleep(bigsleep + (rand() % jitter) );
> else
505a521,522
> if( jitter > 0 )
> wakeup += rand() % jitter;

$ diff -w clamav-0.97.5-original/shared/ clamav-0.97.5/shared/
diff -w clamav-0.97.5-original/shared/optparser.c
clamav-0.97.5/shared/optparser.c
365a366
> { "Jitter", "jitter", 'j', TYPE_NUMBER, MATCH_NUMBER, 12, NULL, 0, OPT_FRESHCLAM, "This option adds random jitter to freshclam's update period.", "0" },

--
Nick Johnson
_______________________________________________
http://lurker.clamav.net/list/clamav-devel.html
Please submit your patches to our Bugzilla: http://bugs.clamav.net

molney at sourcefire

Aug 22, 2012, 9:32 AM

Post #2 of 3 (718 views)
Permalink

Re: Patch: add jitter to freshclam's update period [In reply to]

Added a bug to track this:
https://bugzilla.clamav.net/show_bug.cgi?id=5678

On Wed, Aug 22, 2012 at 12:08 PM, Nick Johnson <npjohnso [at] cs>wrote:

> Hello,
>
> If you are managing a large number of machines, jitter helps spread
> freshclam's network traffic over time so the machines don't all hit
> the network simultaneously.
>
> Here is a patch to add jitter to freshclam's update period. It adds a
> random number of seconds in [0, jitter) to the bigsleep. It adds a
> configuration option "Jitter" (-j, --jitter) to freshclam. The
> default value is zero seconds, which will cause no change to most
> users.
>
> Thank you,
> N
>
>
> $ diff -w clamav-0.97.5-original/freshclam/freshclam.c
> clamav-0.97.5/freshclam/freshclam.c
> 156a157
> > mprintf(" --jitter=#n -j #n random jitter on
> check period, in seconds\n");
> 244a246,248
> > /* Seed random number generator (for Jitter) */
> > srand(time(0));
> >
> 429a434
> > int jitter;
> 455a461,467
> > jitter = optget(opts, "Jitter")->numarg;
> > if( jitter < 0 ) {
> > logg("^Jitter must be a non-negative integer number of seconds.");
> > optfree(opts);
> > return 41;
> > }
> >
> 501a514,516
> > if( jitter > 0 )
> > sleep(bigsleep + (rand() % jitter) );
> > else
> 505a521,522
> > if( jitter > 0 )
> > wakeup += rand() % jitter;
>
> $ diff -w clamav-0.97.5-original/shared/ clamav-0.97.5/shared/
> diff -w clamav-0.97.5-original/shared/optparser.c
> clamav-0.97.5/shared/optparser.c
> 365a366
> > { "Jitter", "jitter", 'j', TYPE_NUMBER, MATCH_NUMBER, 12, NULL, 0,
> OPT_FRESHCLAM, "This option adds random jitter to freshclam's update
> period.", "0" },
>
>
> --
> Nick Johnson
> _______________________________________________
> http://lurker.clamav.net/list/clamav-devel.html
> Please submit your patches to our Bugzilla: http://bugs.clamav.net
>
_______________________________________________
http://lurker.clamav.net/list/clamav-devel.html
Please submit your patches to our Bugzilla: http://bugs.clamav.net

jesler at sourcefire

Aug 22, 2012, 10:15 AM

Post #3 of 3 (713 views)
Permalink

Re: Patch: add jitter to freshclam's update period [In reply to]

Thanks Nick,

We've opened a bug on our side to track this.

--
Joel Esler
Senior Research Engineer, VRT
OpenSource Community Manager
Sourcefire

On Aug 22, 2012, at 12:08 PM, Nick Johnson <npjohnso [at] cs> wrote:

> Hello,
>
> If you are managing a large number of machines, jitter helps spread
> freshclam's network traffic over time so the machines don't all hit
> the network simultaneously.
>
> Here is a patch to add jitter to freshclam's update period. It adds a
> random number of seconds in [0, jitter) to the bigsleep. It adds a
> configuration option "Jitter" (-j, --jitter) to freshclam. The
> default value is zero seconds, which will cause no change to most
> users.
>
> Thank you,
> N
>
>
> $ diff -w clamav-0.97.5-original/freshclam/freshclam.c
> clamav-0.97.5/freshclam/freshclam.c
> 156a157
>> mprintf(" --jitter=#n -j #n random jitter on check period, in seconds\n");
> 244a246,248
>> /* Seed random number generator (for Jitter) */
>> srand(time(0));
>>
> 429a434
>> int jitter;
> 455a461,467
>> jitter = optget(opts, "Jitter")->numarg;
>> if( jitter < 0 ) {
>> logg("^Jitter must be a non-negative integer number of seconds.");
>> optfree(opts);
>> return 41;
>> }
>>
> 501a514,516
>> if( jitter > 0 )
>> sleep(bigsleep + (rand() % jitter) );
>> else
> 505a521,522
>> if( jitter > 0 )
>> wakeup += rand() % jitter;
>
> $ diff -w clamav-0.97.5-original/shared/ clamav-0.97.5/shared/
> diff -w clamav-0.97.5-original/shared/optparser.c
> clamav-0.97.5/shared/optparser.c
> 365a366
>> { "Jitter", "jitter", 'j', TYPE_NUMBER, MATCH_NUMBER, 12, NULL, 0, OPT_FRESHCLAM, "This option adds random jitter to freshclam's update period.", "0" },
>
>
> --
> Nick Johnson
> _______________________________________________
> http://lurker.clamav.net/list/clamav-devel.html
> Please submit your patches to our Bugzilla: http://bugs.clamav.net

_______________________________________________
http://lurker.clamav.net/list/clamav-devel.html
Please submit your patches to our Bugzilla: http://bugs.clamav.net

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