From: Chuck Lever Subject: Re: [PATCH 3/8] SUNRPC: Set V6ONLY socket option for RPC listener sockets Date: Thu, 14 Aug 2008 16:34:14 -0400 Message-ID: <74E488BD-DB15-41CD-AD30-A8A5213BC140@oracle.com> References: <20080813223653.13068.9467.stgit@manray.1015granger.net> <20080813223953.13068.97829.stgit@manray.1015granger.net> <20080814200554.GI23859@fieldses.org> Mime-Version: 1.0 (Apple Message framework v928.1) Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Cc: trond.myklebust@netapp.com, trond.myklebust@fys.uio.no, linux-nfs@vger.kernel.org To: "J. Bruce Fields" Return-path: Received: from rgminet01.oracle.com ([148.87.113.118]:25492 "EHLO rgminet01.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751213AbYHNUei (ORCPT ); Thu, 14 Aug 2008 16:34:38 -0400 In-Reply-To: <20080814200554.GI23859@fieldses.org> Sender: linux-nfs-owner@vger.kernel.org List-ID: 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. >> 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