Name

loc_network_cmp, loc_network_matches_address, loc_network_overlaps, loc_network_is_subnet, loc_network_subnets, loc_network_exclude, loc_network_exclude_list - Compare networks and take them apart

Synopsis

#include <libloc/network.h>

int loc_network_cmp(struct loc_network* self, struct loc_network* other);

int loc_network_matches_address(struct loc_network* network,
        const struct in6_addr* address);

int loc_network_overlaps(struct loc_network* self, struct loc_network* other);

int loc_network_is_subnet(struct loc_network* self, struct loc_network* other);

int loc_network_subnets(struct loc_network* network,
        struct loc_network** subnet1, struct loc_network** subnet2);

struct loc_network_list* loc_network_exclude(struct loc_network* self,
        struct loc_network* other);

struct loc_network_list* loc_network_exclude_list(struct loc_network* network,
        struct loc_network_list* list);

Description

loc_network_cmp() compares two networks by their first address, and then by the length of their prefix, so that a network comes before its subnets. It can be used to sort networks.

loc_network_matches_address() checks whether address is in network. IPv4 addresses have to be IPv4-mapped (see loc_network_new(3)).

loc_network_overlaps() checks whether the two networks have any addresses in common.

loc_network_is_subnet() checks whether other is inside self, which includes that both are the same network.

loc_network_subnets() splits network into its two halves, which are one bit longer. For example, 192.0.2.0/24 becomes 192.0.2.0/25 and 192.0.2.128/25. Both have the same country, Autonomous System and flags as network.

loc_network_exclude() returns the smallest list of networks which contain all addresses of self except those that are in other. loc_network_exclude_list() does the same for all networks in list. If nothing overlaps, the result only contains the network itself. The networks in the result have the same country, Autonomous System and flags as the network that they have been taken from.

Return Value

loc_network_cmp() returns a negative number, zero, or a positive number if self is smaller than, the same as, or larger than other, just like strcmp(3).

loc_network_matches_address(), loc_network_overlaps() and loc_network_is_subnet() return 1 if this is true, and zero otherwise.

loc_network_subnets() returns zero on success, and a negative error number (see errno(3)) on error, for example -EINVAL if network cannot be split because it only has one address.

loc_network_exclude() and loc_network_exclude_list() return a new list, which the caller has to release, or NULL if an error occurred.

Example

Print all of 192.0.2.0/24 except 192.0.2.64/26:

struct loc_network_list* list = loc_network_exclude(network, other);

if (list) {
        for (size_t i = 0; i < loc_network_list_size(list); i++) {
                struct loc_network* n = loc_network_list_get(list, i);

                printf("%s\n", loc_network_str(n));
                loc_network_unref(n);
        }

        loc_network_list_unref(list);
}

This prints 192.0.2.0/26 and 192.0.2.128/25.

See Also

libloc(3), loc_network_new(3), loc_network_list_new(3)

Authors

Michael Tremer