Date: Wed, 26 Nov 1997 18:40:17 +0100 (MET) From: Luigi Rizzo <luigi@labinfo.iet.unipi.it> To: luigi@labinfo.iet.unipi.it (Luigi Rizzo) Cc: hackers@freebsd.org Subject: Re: udp question related to icmp... Message-ID: <199711261740.SAA07496@labinfo.iet.unipi.it> In-Reply-To: <199711261719.SAA07459@labinfo.iet.unipi.it> from "Luigi Rizzo" at Nov 26, 97 06:19:24 pm
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[added -multimedia in Bcc because the problem seems to affect vat...]
> Further investigation in vat sources (net.cc) shows that the problem is
> well known (although not mentioned in the manpages). I was almost going
> to apply the fix to the kernel mentioned in vat's net.cc when I
> realized that after all it is not such a terrible idea to report failures
> (due to ICMP port unreachable) up to the application, if nothing else
> to avoid flooding the net with undesired data.
more on this: from vat's sources (net.cc):
* This bug originated at CSRG in Berkeley
* and was present in the BSD Reno networking
* code release. It has since been fixed
* in 4.4BSD and OSF-3.x. It is know to remain
* in AIX-4.1.3.
*
* A fix is to change the following lines from
* kern/uipc_socket.c:
*
* if (so_serror)
* snderr(so->so_error);
*
* to:
*
* if (so->so_error) {
* error = so->so_error;
* so->so_error = 0;
* splx(s);
* goto release;
* }
looking at our kern/uipc_socket.c (i am running 2.2.1) it appears
that the fix has been applied in some way only in soreceive, not
in sosend. So I am a bit unsure about the above comment related
to 4.4BSD ... this would also explain why, in some cases, when I fire vat
using unicast before the remote party, i cannot be heard...
Luigi
>
> So... I started writing this email looking for a fix, but now I guess I
> just have to point this behaviour to your attention...
>
> Cheers
> Luigi
> -----------------------------+--------------------------------------
> Luigi Rizzo | Dip. di Ingegneria dell'Informazione
> email: luigi@iet.unipi.it | Universita' di Pisa
> tel: +39-50-568533 | via Diotisalvi 2, 56126 PISA (Italy)
> fax: +39-50-568522 | http://www.iet.unipi.it/~luigi/
> _____________________________|______________________________________
>
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