cflowd with incorrect statistics

From: Alexandre Peixoto Ferreira (
Date: Wed Sep 27 2000 - 06:30:44 PDT

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    I have discovered a bug in Cflowd that inflates the statistics. The bug
    is related to a race condition in the code for the locking of
    shared-memory. This bug when hit allows cflowd to processes again old
    flows already processed, distorting the statistics to higher values.

    There is a patch included with this e-mail that corrects the problem and
    simplifies the debugging processes by modifying flowwatch to record for
    each flow a timestamp and a sequence number. Flowwatch can read old
    dumps but new dumps can not be read by an old flowwatch.

    I think this bug has been around for a while and been a subject of many
    discussions in this list before (I've checked the maillist archive).

    Any question can be directed to me.

    To apply the patch just use the command below:

    cd <directory where the source of cflowd is installed>/cflowd-2-1.a9
    gunzip -c cflowd-2-1.a9.patch.gz | patch -p1

    recompile and good luck.


    Alexandre P. Ferreira
    Empresa de Correios e Telégrafos

    cflowd mailing list

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