[XFRM]: Fix wildcard as tunnel source

Hashing SAs by source address breaks templates with wildcards as tunnel
source since the source address used for hashing/lookup is still 0/0.
Move source address lookup to xfrm_tmpl_resolve_one() so we can use the
real address in the lookup.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/xfrm6_policy.c b/net/ipv6/xfrm6_policy.c
index 9391c4c..6a252e2 100644
--- a/net/ipv6/xfrm6_policy.c
+++ b/net/ipv6/xfrm6_policy.c
@@ -34,6 +34,26 @@
 	return err;
 }
 
+static int xfrm6_get_saddr(xfrm_address_t *saddr, xfrm_address_t *daddr)
+{
+	struct rt6_info *rt;
+	struct flowi fl_tunnel = {
+		.nl_u = {
+			.ip6_u = {
+				.daddr = *(struct in6_addr *)&daddr->a6,
+			},
+		},
+	};
+
+	if (!xfrm6_dst_lookup((struct xfrm_dst **)&rt, &fl_tunnel)) {
+		ipv6_get_saddr(&rt->u.dst, (struct in6_addr *)&daddr->a6,
+			       (struct in6_addr *)&saddr->a6);
+		dst_release(&rt->u.dst);
+		return 0;
+	}
+	return -EHOSTUNREACH;
+}
+
 static struct dst_entry *
 __xfrm6_find_bundle(struct flowi *fl, struct xfrm_policy *policy)
 {
@@ -362,6 +382,7 @@
 	.family =		AF_INET6,
 	.dst_ops =		&xfrm6_dst_ops,
 	.dst_lookup =		xfrm6_dst_lookup,
+	.get_saddr = 		xfrm6_get_saddr,
 	.find_bundle =		__xfrm6_find_bundle,
 	.bundle_create =	__xfrm6_bundle_create,
 	.decode_session =	_decode_session6,