From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S964977AbWFNOe7 (ORCPT ); Wed, 14 Jun 2006 10:34:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S964981AbWFNOe7 (ORCPT ); Wed, 14 Jun 2006 10:34:59 -0400 Received: from outpipe-village-512-1.bc.nu ([81.2.110.250]:58561 "EHLO lxorguk.ukuu.org.uk") by vger.kernel.org with ESMTP id S964977AbWFNOe6 (ORCPT ); Wed, 14 Jun 2006 10:34:58 -0400 Subject: Re: SO_REUSEPORT and multicasting From: Alan Cox To: Jason Cc: Jan Engelhardt , linux-kernel@vger.kernel.org In-Reply-To: <20060614142653.71443.qmail@web53606.mail.yahoo.com> References: <20060614142653.71443.qmail@web53606.mail.yahoo.com> Content-Type: text/plain Content-Transfer-Encoding: 7bit Date: Wed, 14 Jun 2006 15:51:07 +0100 Message-Id: <1150296668.3490.46.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.6.2 (2.6.2-1.fc5.5) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Ar Mer, 2006-06-14 am 07:26 -0700, ysgrifennodd Jason: > > Have you bound to a multicast group in your program? > > If BSD supports it why can't Linux? Linux follows the standards draft. SO_REUSEPORT is fairly obscure BSDism. > Yes. My code works great on HP-UX but does nothing on > Linux. That doesn't actually prove very much. Its very easy to write incorrect code that only works on one system, especially when endian-ness gets involved with network code. In particular if writing portable code you must remember to join the group. You must also remember that the various htons/htonl macros need to be correctly used or your code will break on little-endian systems. The default IP_MULTICAST_LOOP value is probably also worth overriding if you are being fairly paranoid.