From b6632339e3afbcbb438a3c8935190ea22464fc99 Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Mon, 18 Aug 2008 19:33:44 -0400 Subject: [PATCH] SUNRPC: Set V6ONLY socket option for RPC listener sockets 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. 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 Signed-off-by: J. Bruce Fields --- net/sunrpc/svcsock.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c index 3e65719f1ef6..f91377c14951 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); -- 2.20.1