Mailing List Archive

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
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