export: Skip writing any subnets

[people/ms/libloc.git] / src / network.c

diff --git a/src/network.c b/src/network.c
index 5a8db7a58b7f30e2286bb23653cd7c254d13ff2b..286e13685498befb84c80db7421cf47ff450ad9b 100644 (file)
--- a/src/network.c
+++ b/src/network.c
@@ -346,6 +346,24 @@ LOC_EXPORT int loc_network_match_flag(struct loc_network* network, uint32_t flag
        return loc_network_has_flag(network, flag);
 }
 
+LOC_EXPORT int loc_network_is_subnet_of(struct loc_network* self, struct loc_network* other) {
+       // If the start address of the other network is smaller than this network,
+       // it cannot be a subnet.
+       if (in6_addr_cmp(&self->start_address, &other->start_address) < 0)
+               return 0;
+
+       // Get the end addresses
+       struct in6_addr last_address_self  = make_last_address(&self->start_address,  self->prefix);
+       struct in6_addr last_address_other = make_last_address(&other->start_address, other->prefix);
+
+       // If the end address of the other network is greater than this network,
+       // it cannot be a subnet.
+       if (in6_addr_cmp(&last_address_self, &last_address_other) > 0)
+               return 0;
+
+       return 1;
+}
+
 LOC_EXPORT int loc_network_to_database_v1(struct loc_network* network, struct loc_database_network_v1* dbobj) {
        // Add country code
        loc_country_code_copy(dbobj->country_code, network->country_code);