From owner-freebsd-hackers Wed Nov 26 10:24:44 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id KAA06955 for hackers-outgoing; Wed, 26 Nov 1997 10:24:44 -0800 (PST) (envelope-from owner-freebsd-hackers) 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 KAA06933; Wed, 26 Nov 1997 10:24:18 -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 SAA07459; Wed, 26 Nov 1997 18:19:44 +0100 From: Luigi Rizzo Message-Id: <199711261719.SAA07459@labinfo.iet.unipi.it> Subject: udp question related to icmp... To: hackers@freebsd.org Date: Wed, 26 Nov 1997 18:19:43 +0100 (MET) X-Mailer: ELM [version 2.4 PL23] Content-Type: text Sender: owner-freebsd-hackers@freebsd.org X-Loop: FreeBSD.org Precedence: bulk Hi, just now i tried to use connect on a SOCK_DGRAM to avoid having to specify the destination address every time. Things worked perfectly with multicast, and by pure luck they worked while i was doing testing on my machine. When i tried with a remote machine which was not listening, a problem came out: the remote machine was (presumably) sending back ICMP port unreachable, which caused the kernel to disable further writes to that socket, so after the first few packets, nothing went out anymore. 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. 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/ _____________________________|______________________________________