Date: Sat, 3 Aug 2002 10:00:09 -0700 From: Luigi Rizzo <rizzo@icir.org> To: Valentine Zaretsky <valik@apex.dp.ua> Cc: ipfw@FreeBSD.ORG Subject: Re: ipfw2 & dummynet Message-ID: <20020803100008.A98813@iguana.icir.org> In-Reply-To: <007601c23b07$8c667550$226e03d4@zhome>; from valik@apex.dp.ua on Sat, Aug 03, 2002 at 07:05:08PM %2B0300 References: <007601c23b07$8c667550$226e03d4@zhome>
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good catch :)
The problem was in fact a missing #include "opt_ipdn.h" to let us know
whether we are being compiled for the old ipfw or for IPFW2.
Without that, compilation defaulted to ipfw, resulting in
a number of erroneous manipulations of data.
Just committed a fix, thanks
luigi
On Sat, Aug 03, 2002 at 07:05:08PM +0300, Valentine Zaretsky wrote:
> Hi,
>
> Playing with ipfw2 in -stable (last time cvsup'ed yesterday), I found a bug when using dummynet pipes and queues
>
> Here is the simplest example to repeat it:
>
> ipfw pipe 1 config bw 20KBytes/s
> ipfw add 400 pipe 1 ip from any to me
>
> The first packet matching rule 400 leads to kernel panic caused by "division by zero"
>
> Analyzing crashdump with gdb, I found that it happens in the following code in /usr/src/sys/netinet/ip_dummynet.c:
> (lines 1198-1205)
> ==============================
> if (DN_KEY_GT(q->S, q->F)) { /* means timestamps are invalid */
> q->S = pipe->V ;
> pipe->sum += fs->weight ; /* add weight of new queue */
> } else {
> heap_extract(&(pipe->idle_heap), q);
> q->S = MAX64(q->F, pipe->V ) ;
> }
> q->F = q->S + ( len<<MY_M )/(u_int64_t) fs->weight;
> ==============================
>
> So the weight is 0 when it should be 1.
> And it's not quite understood why should this code execute at all? There is no queues (only simple pipe, so "is_pipe" should be 1)
>
> Adding dumb "if(fs->weight==0) fs->weight=1;" before the code above, fixes this kernel panic.
>
> I think it could/should be fixed a little smarter ;)
>
> --
> With best regards, Valentine Zaretsky
>
>
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