From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrew Morton Subject: Re: [Bugme-new] [Bug 15720] New: IPv6's ipv4-compatibility addresses don't bind Date: Mon, 12 Apr 2010 21:22:41 -0400 Message-ID: <20100412212241.d8bf4185.akpm@linux-foundation.org> References: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: bugzilla-daemon@bugzilla.kernel.org, bugme-daemon@bugzilla.kernel.org, charles@kde.org To: netdev@vger.kernel.org Return-path: Received: from smtp1.linux-foundation.org ([140.211.169.13]:54932 "EHLO smtp1.linux-foundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750727Ab0DMEZl (ORCPT ); Tue, 13 Apr 2010 00:25:41 -0400 In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: (switched to email. Please respond via emailed reply-to-all, not via the bugzilla web interface). On Wed, 7 Apr 2010 23:17:32 GMT bugzilla-daemon@bugzilla.kernel.org wrote: > https://bugzilla.kernel.org/show_bug.cgi?id=15720 > > Summary: IPv6's ipv4-compatibility addresses don't bind A 2.6.9 -> 2.6.32 regression ;) > Product: Networking > Version: 2.5 > Kernel Version: 2.6.32-2-686-bigmem > Platform: All > OS/Version: Linux > Tree: Mainline > Status: NEW > Severity: normal > Priority: P1 > Component: IPV6 > AssignedTo: yoshfuji@linux-ipv6.org > ReportedBy: charles@kde.org > Regression: Yes > > > When attempting to bind to an address using ipv4-compatibility, for example, > "::ffff:127.0.0.1", Linux refuses to bind to that address when > /proc/sys/net/ipv6/bindv6only is set. > > Yes, you could say "but you specifically told ipv6 to not bind to ipv4 > addresses!" However, ::ffff:127.0.0.1 is *clearly* an ipv4 address, it's not an > alternate representation of an ipv6 address, it's an ipv4 address and only > ipv4. > > This seems to not have been the case as of linux 2.6.9, although I'm not sure > at what version this changed. > > It seems to me that the intent of "bindv6only" was to not bind to the ipv4 > address when you bind to all addresses (specifically ipv6 address "::"). So > when you bind to ::, an ipv4 client connects to you, and it appears to be > connecting from ::ffff:192.168.5.5. I don't think its intent was to effectively > disable binding to ::ffff:x.x.x.x addresses - just breaking that feature makes > no sense. > > The Linux 2.6.9 approach seems to match MacOS's (and I'm pretty sure Solaris's, > too).