ipops: mask subnet address when comparing

- allow using full ip address when specifying subnet parameter
- more flexibility on using values from sip message
- GH #1250

(cherry picked from commit 1f675c6)

src/modules/ipops/ipops_mod.c

@@ -390,7 +390,7 @@ int _ip_is_in_subnet_v4(struct in_addr *ip, char *net, size_t netlen,
 	if (netmask == 32) ipv4_mask = 0xFFFFFFFF;
 	else ipv4_mask = htonl(~(0xFFFFFFFF >> netmask));
 
-	if ((ip->s_addr & ipv4_mask) == net_addr.s_addr)
+	if ((ip->s_addr & ipv4_mask) == (net_addr.s_addr & ipv4_mask))
 		return 1;
 	return 0;
 }
@@ -1456,4 +1456,4 @@ int mod_register(char *path, int *dlflags, void *p1, void *p2)
 {
 	sr_kemi_modules_add(sr_kemi_ipops_exports);
 	return 0;
-}
+}