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 <makc@xxxxxxx> 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 <chuck.lever@xxxxxxxxxx>
>>> ---
>>>
>>> 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
>
>
>
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