ipv6: Early TCP socket demux

This is the IPv6 missing bits for infrastructure added in commit
41063e9dd1195 (ipv4: Early TCP socket demux.)

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/ip6_input.c b/net/ipv6/ip6_input.c
index 5ab923e..47975e3 100644
--- a/net/ipv6/ip6_input.c
+++ b/net/ipv6/ip6_input.c
@@ -47,9 +47,18 @@
 
 
 
-inline int ip6_rcv_finish( struct sk_buff *skb)
+int ip6_rcv_finish(struct sk_buff *skb)
 {
-	if (skb_dst(skb) == NULL)
+	if (sysctl_ip_early_demux && !skb_dst(skb)) {
+		const struct inet6_protocol *ipprot;
+
+		rcu_read_lock();
+		ipprot = rcu_dereference(inet6_protos[ipv6_hdr(skb)->nexthdr]);
+		if (ipprot && ipprot->early_demux)
+			ipprot->early_demux(skb);
+		rcu_read_unlock();
+	}
+	if (!skb_dst(skb))
 		ip6_route_input(skb);
 
 	return dst_input(skb);