ip6_tunnel: Add support for wildcard tunnel endpoints.

This patch adds support for tunnels with local or
remote wildcard endpoints. With this we get a
NBMA tunnel mode like we have it for ipv4 and
sit tunnels.
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/ip6_tunnel.c

@@ -183,6 +183,7 @@ ip6_tnl_lookup(struct net *net, const struct in6_addr *remote, const struct in6_
 	unsigned int hash = HASH(remote, local);
 	struct ip6_tnl *t;
 	struct ip6_tnl_net *ip6n = net_generic(net, ip6_tnl_net_id);
+	struct in6_addr any;
 
 	for_each_ip6_tunnel_rcu(ip6n->tnls_r_l[hash]) {
 		if (ipv6_addr_equal(local, &t->parms.laddr) &&
@@ -190,6 +191,22 @@ ip6_tnl_lookup(struct net *net, const struct in6_addr *remote, const struct in6_
 		    (t->dev->flags & IFF_UP))
 			return t;
 	}
+
+	memset(&any, 0, sizeof(any));
+	hash = HASH(&any, local);
+	for_each_ip6_tunnel_rcu(ip6n->tnls_r_l[hash]) {
+		if (ipv6_addr_equal(local, &t->parms.laddr) &&
+		    (t->dev->flags & IFF_UP))
+			return t;
+	}
+
+	hash = HASH(remote, &any);
+	for_each_ip6_tunnel_rcu(ip6n->tnls_r_l[hash]) {
+		if (ipv6_addr_equal(remote, &t->parms.raddr) &&
+		    (t->dev->flags & IFF_UP))
+			return t;
+	}
+
 	t = rcu_dereference(ip6n->tnls_wc[0]);
 	if (t && (t->dev->flags & IFF_UP))
 		return t;
@@ -979,7 +996,29 @@ static int ip6_tnl_xmit2(struct sk_buff *skb,
 	u8 proto;
 	int err = -1;
 
-	if (!fl6->flowi6_mark)
+	/* NBMA tunnel */
+	if (ipv6_addr_any(&t->parms.raddr)) {
+		struct in6_addr *addr6;
+		struct neighbour *neigh;
+		int addr_type;
+
+		if (!skb_dst(skb))
+			goto tx_err_link_failure;
+
+		neigh = dst_neigh_lookup(skb_dst(skb),
+					 &ipv6_hdr(skb)->daddr);
+		if (!neigh)
+			goto tx_err_link_failure;
+
+		addr6 = (struct in6_addr *)&neigh->primary_key;
+		addr_type = ipv6_addr_type(addr6);
+
+		if (addr_type == IPV6_ADDR_ANY)
+			addr6 = &ipv6_hdr(skb)->daddr;
+
+		memcpy(&fl6->daddr, addr6, sizeof(fl6->daddr));
+		neigh_release(neigh);
+	} else if (!fl6->flowi6_mark)
 		dst = ip6_tnl_dst_check(t);
 
 	if (!ip6_tnl_xmit_ctl(t, &fl6->saddr, &fl6->daddr))