From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?utf-8?Q?Bj=C3=B8rn_Mork?= Subject: Re: [Patch net-next] ipv6: separate out procfs code from mcast.c Date: Tue, 23 Apr 2013 14:33:57 +0200 Message-ID: <87d2tlv32i.fsf@nemi.mork.no> References: <1366701302.21136.19.camel@cr0> <20130423.031805.544535198246859192.davem@davemloft.net> <1366702220.21136.23.camel@cr0> <20130423.033620.1101068519499870853.davem@davemloft.net> <1366702893.21136.28.camel@cr0> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: David Miller , netdev@vger.kernel.org, yoshfuji@linux-ipv6.org To: Cong Wang Return-path: Received: from canardo.mork.no ([148.122.252.1]:59468 "EHLO canardo.mork.no" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755000Ab3DWMeP convert rfc822-to-8bit (ORCPT ); Tue, 23 Apr 2013 08:34:15 -0400 In-Reply-To: <1366702893.21136.28.camel@cr0> (Cong Wang's message of "Tue, 23 Apr 2013 15:41:33 +0800") Sender: netdev-owner@vger.kernel.org List-ID: Cong Wang writes: > On Tue, 2013-04-23 at 03:36 -0400, David Miller wrote: >> From: Cong Wang >> Date: Tue, 23 Apr 2013 15:30:20 +0800 >>=20 >> > This is hard to do, as in the email I replied to Stephen. So I >> > prefer to just add a Kconfig dependency, at least for now. >>=20 >> A Kconfig hack is exactly what I've told you is an unacceptable >> solution. > > Please enlighten me for a third solution. :) This is an completely untested idea.... I note that vxlan_init_net requires a successful sock_create_kern(). That implies a request_module("net-pf-...") followed by try_module_get. So if the sock_create_kern(PF_INET6, ..) succeeds then you *know* you have IPv6. If it fails with -EAFNOSUPPORT, then you could fall back to sock_create_kern(PF_INET, ..) and set a flag indicating that runtime IPv6 support is disabled. Then use this flag to allow/deny configuring any IPv6 destinations. You may also have to protect the IPv6 modular symbols you use with symbol_request() or similar to prevent vxlan from depending on IPv6. I dunno... If nothing else, I believe this is a crazy enough hack that David may want to reconsider one of your other two solutions :) Bj=C3=B8rn