netfilter: nf_nat_core: eliminate useless find_appropriate_src for IP_NAT_RANGE_PROTO_RANDOM

Signed-off-by: NChangli Gao <xiaosuo@gmail.com>
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/netfilter/nf_nat_core.c

@@ -240,10 +240,10 @@ get_unique_tuple(struct nf_conntrack_tuple *tuple,
 	   This is only required for source (ie. NAT/masq) mappings.
 	   So far, we don't do local source mappings, so multiple
 	   manips not an issue.  */
-	if (maniptype == IP_NAT_MANIP_SRC) {
+	if (maniptype == IP_NAT_MANIP_SRC &&
+	    !(range->flags & IP_NAT_RANGE_PROTO_RANDOM)) {
 		if (find_appropriate_src(orig_tuple, tuple, range)) {
 			pr_debug("get_unique_tuple: Found current src map\n");
-			if (!(range->flags & IP_NAT_RANGE_PROTO_RANDOM))
 			if (!nf_nat_used_tuple(tuple, ct))
 				return;
 		}