From mboxrd@z Thu Jan 1 00:00:00 1970 From: "J. Bruce Fields" Subject: Re: [PATCH 3/8] SUNRPC: Set V6ONLY socket option for RPC listener sockets Date: Thu, 14 Aug 2008 16:38:33 -0400 Message-ID: <20080814203833.GK23859@fieldses.org> References: <20080813223653.13068.9467.stgit@manray.1015granger.net> <20080813223953.13068.97829.stgit@manray.1015granger.net> <20080814200554.GI23859@fieldses.org> <74E488BD-DB15-41CD-AD30-A8A5213BC140@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: trond.myklebust@netapp.com, trond.myklebust@fys.uio.no, linux-nfs@vger.kernel.org To: Chuck Lever Return-path: Received: from mail.fieldses.org ([66.93.2.214]:55926 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753636AbYHNUii (ORCPT ); Thu, 14 Aug 2008 16:38:38 -0400 In-Reply-To: <74E488BD-DB15-41CD-AD30-A8A5213BC140@oracle.com> Sender: linux-nfs-owner@vger.kernel.org List-ID: On Thu, Aug 14, 2008 at 04:34:14PM -0400, Chuck Lever wrote: > On Aug 14, 2008, at 4:05 PM, J. Bruce Fields wrote: >> On Wed, Aug 13, 2008 at 06:39:54PM -0400, Chuck Lever wrote: >>> My plan is to use an AF_INET listener on systems that support only >>> IPv4, >>> and an AF_INET6 listener on systems that can support IPv6. Incoming >>> IPv4 packets will be posted to an AF_INET6 listener with a mapped >>> IPv4 >>> address. >> >> How will the nfs server choose whether to use AF_INET or AF_INET6? >> Will >> we need some new user interface? > > [PATCH 2/8] changes svc_create() to take an additional argument which > specifies the listener's address family. This value is stored in > svc_serv. Right, but I'm asking about the nfsd server, not the rpc server, and the user interface, not the in-kernel interface: so suppose I'm a server administrator, and want my nfs server to listen for ipv6 connections. Will there be some switch I'll need to flip? --b. > >>> Max Matveev says: >>> Creating a single listener can be dangerous - if net.ipv6.bindv6only >>> is enabled then it's possible to create another listener in v4 >>> namespace on the same port and steal the traffic from the "unifed" >>> listener. You need to disable V6ONLY explicitly via a sockopt to >>> stop >>> that. >>> >>> Set appropriate socket option on RPC server listener sockets to >>> prevent >>> this. >>> >>> Signed-off-by: Chuck Lever >>> --- >>> >>> net/sunrpc/svcsock.c | 13 +++++++++++++ >>> 1 files changed, 13 insertions(+), 0 deletions(-) >>> >>> diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c >>> index 3e65719..f91377c 100644 >>> --- a/net/sunrpc/svcsock.c >>> +++ b/net/sunrpc/svcsock.c >>> @@ -1114,6 +1114,7 @@ static struct svc_sock >>> *svc_setup_socket(struct svc_serv *serv, >>> struct svc_sock *svsk; >>> struct sock *inet; >>> int pmap_register = !(flags & SVC_SOCK_ANONYMOUS); >>> + int val; >>> >>> dprintk("svc: svc_setup_socket %p\n", sock); >>> if (!(svsk = kzalloc(sizeof(*svsk), GFP_KERNEL))) { >>> @@ -1146,6 +1147,18 @@ static struct svc_sock >>> *svc_setup_socket(struct svc_serv *serv, >>> else >>> svc_tcp_init(svsk, serv); >>> >>> + /* >>> + * We start one listener per sv_serv. We want AF_INET >>> + * requests to be automatically shunted to our AF_INET6 >>> + * listener using a mapped IPv4 address. Make sure >>> + * no-one starts an equivalent IPv4 listener, which >>> + * would steal our incoming connections. >>> + */ >>> + val = 0; >>> + if (serv->sv_family == AF_INET6) >>> + kernel_setsockopt(sock, SOL_IPV6, IPV6_V6ONLY, >>> + (char *)&val, sizeof(val)); >>> + >>> dprintk("svc: svc_setup_socket created %p (inet %p)\n", >>> svsk, svsk->sk_sk); >>> >>> > > -- > Chuck Lever > chuck[dot]lever[at]oracle[dot]com > > >