[IPSEC]: Use the correct family for input state lookup

When merging the input paths of IPsec I accidentally left a hard-coded
AF_INET for the state lookup call.  This broke IPv6 obviously.  This
patch fixes by getting the input callers to specify the family through
skb->cb.

Credit goes to Kazunori Miyazawa for diagnosing this and providing an
initial patch.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/xfrm/xfrm_input.c b/net/xfrm/xfrm_input.c
index 96f42c1..8b2b1b5 100644
--- a/net/xfrm/xfrm_input.c
+++ b/net/xfrm/xfrm_input.c
@@ -102,6 +102,7 @@
 	__be32 seq;
 	struct xfrm_state *x;
 	xfrm_address_t *daddr;
+	unsigned int family;
 	int decaps = 0;
 	int async = 0;
 
@@ -127,6 +128,7 @@
 
 	daddr = (xfrm_address_t *)(skb_network_header(skb) +
 				   XFRM_SPI_SKB_CB(skb)->daddroff);
+	family = XFRM_SPI_SKB_CB(skb)->family;
 
 	seq = 0;
 	if (!spi && (err = xfrm_parse_spi(skb, nexthdr, &spi, &seq)) != 0)
@@ -136,7 +138,7 @@
 		if (skb->sp->len == XFRM_MAX_DEPTH)
 			goto drop;
 
-		x = xfrm_state_lookup(daddr, spi, nexthdr, AF_INET);
+		x = xfrm_state_lookup(daddr, spi, nexthdr, family);
 		if (x == NULL)
 			goto drop;
 
@@ -198,6 +200,7 @@
 		 * transport mode so the outer address is identical.
 		 */
 		daddr = &x->id.daddr;
+		family = x->outer_mode->afinfo->family;
 
 		err = xfrm_parse_spi(skb, nexthdr, &spi, &seq);
 		if (err < 0)