[IPSEC]: Fix transport-mode async resume on intput without netfilter

When netfilter is off the transport-mode async resumption doesn't work
because we don't push back the IP header.  This patch fixes that by
moving most of the code outside of ifdef NETFILTER since the only part
that's not common is the short-circuit in the protocol handler.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/xfrm4_input.c

@@ -51,7 +51,11 @@ int xfrm4_transport_finish(struct sk_buff *skb, int async)
 
 	iph->protocol = XFRM_MODE_SKB_CB(skb)->protocol;
 
-#ifdef CONFIG_NETFILTER
+#ifndef CONFIG_NETFILTER
+	if (!async)
+		return -iph->protocol;
+#endif
+
 	__skb_push(skb, skb->data - skb_network_header(skb));
 	iph->tot_len = htons(skb->len);
 	ip_send_check(iph);
@@ -59,12 +63,6 @@ int xfrm4_transport_finish(struct sk_buff *skb, int async)
 	NF_HOOK(PF_INET, NF_INET_PRE_ROUTING, skb, skb->dev, NULL,
 		xfrm4_rcv_encap_finish);
 	return 0;
-#else
-	if (async)
-		return xfrm4_rcv_encap_finish(skb);
-
-	return -iph->protocol;
-#endif
 }
 
 /* If it's a keepalive packet, then just eat it.

net/ipv6/xfrm6_input.c

@@ -34,19 +34,17 @@ int xfrm6_transport_finish(struct sk_buff *skb, int async)
 	skb_network_header(skb)[IP6CB(skb)->nhoff] =
 		XFRM_MODE_SKB_CB(skb)->protocol;
 
-#ifdef CONFIG_NETFILTER
+#ifndef CONFIG_NETFILTER
+	if (!async)
+		return 1;
+#endif
+
 	ipv6_hdr(skb)->payload_len = htons(skb->len);
 	__skb_push(skb, skb->data - skb_network_header(skb));
 
 	NF_HOOK(PF_INET6, NF_INET_PRE_ROUTING, skb, skb->dev, NULL,
 		ip6_rcv_finish);
 	return -1;
-#else
-	if (async)
-		return ip6_rcv_finish(skb);
-
-	return 1;
-#endif
 }
 
 int xfrm6_rcv(struct sk_buff *skb)