From owner-freebsd-multimedia Wed Nov 26 10:45:03 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id KAA08656 for multimedia-outgoing; Wed, 26 Nov 1997 10:45:03 -0800 (PST) (envelope-from owner-freebsd-multimedia) Received: from labinfo.iet.unipi.it (labinfo.iet.unipi.it [131.114.9.5]) by hub.freebsd.org (8.8.7/8.8.7) with SMTP id KAA08637; Wed, 26 Nov 1997 10:44:52 -0800 (PST) (envelope-from luigi@labinfo.iet.unipi.it) Received: from localhost (luigi@localhost) by labinfo.iet.unipi.it (8.6.5/8.6.5) id SAA07496; Wed, 26 Nov 1997 18:40:17 +0100 From: Luigi Rizzo Message-Id: <199711261740.SAA07496@labinfo.iet.unipi.it> Subject: Re: udp question related to icmp... To: luigi@labinfo.iet.unipi.it (Luigi Rizzo) Date: Wed, 26 Nov 1997 18:40:17 +0100 (MET) Cc: hackers@freebsd.org In-Reply-To: <199711261719.SAA07459@labinfo.iet.unipi.it> from "Luigi Rizzo" at Nov 26, 97 06:19:24 pm X-Mailer: ELM [version 2.4 PL23] Content-Type: text Sender: owner-freebsd-multimedia@freebsd.org X-Loop: FreeBSD.org Precedence: bulk [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/ > _____________________________|______________________________________ >