From: "J. Bruce Fields" Subject: Re: [PATCH 3/8] SUNRPC: Set V6ONLY socket option for RPC listener sockets Date: Wed, 20 Aug 2008 15:31:26 -0400 Message-ID: <20080820193126.GB21226@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> <20080814203833.GK23859@fieldses.org> 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]:56300 "EHLO fieldses.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754930AbYHTTbe (ORCPT ); Wed, 20 Aug 2008 15:31:34 -0400 In-Reply-To: Sender: linux-nfs-owner@vger.kernel.org List-ID: On Thu, Aug 14, 2008 at 04:45:31PM -0400, Chuck Lever wrote: > On Aug 14, 2008, at 4:38 PM, J. Bruce Fields wrote: >> 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: > > Ah. That wasn't clear before. > >> 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? > > I don't know how that UI will be designed. So far, I've focused only on > the pieces needed for client side IPv6 support. I figured the Bull team > had something figured out for the server, and didn't think any more about > it. I've forgotten who was working on that; Aurelien Charbon? --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 >>> >>> >>> > > -- > Chuck Lever > chuck[dot]lever[at]oracle[dot]com > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-nfs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html