kernel-interface: Add method to enumerate locally attached subnets

src/libcharon/kernel/kernel_interface.c

@@ -554,6 +554,16 @@ METHOD(kernel_interface_t, create_address_enumerator, enumerator_t*,
 	return this->net->create_address_enumerator(this->net, which);
 }
 
+METHOD(kernel_interface_t, create_local_subnet_enumerator, enumerator_t*,
+	private_kernel_interface_t *this)
+{
+	if (!this->net || !this->net->create_local_subnet_enumerator)
+	{
+		return enumerator_create_empty();
+	}
+	return this->net->create_local_subnet_enumerator(this->net);
+}
+
 METHOD(kernel_interface_t, add_ip, status_t,
 	private_kernel_interface_t *this, host_t *virtual_ip, int prefix,
 	char *iface)
@@ -1005,6 +1015,7 @@ kernel_interface_t *kernel_interface_create()
 			.get_nexthop = _get_nexthop,
 			.get_interface = _get_interface,
 			.create_address_enumerator = _create_address_enumerator,
+			.create_local_subnet_enumerator = _create_local_subnet_enumerator,
 			.add_ip = _add_ip,
 			.del_ip = _del_ip,
 			.add_route = _add_route,

src/libcharon/kernel/kernel_interface.h

@@ -315,6 +315,15 @@ struct kernel_interface_t {
 	enumerator_t *(*create_address_enumerator) (kernel_interface_t *this,
 												kernel_address_type_t which);
 
+	/**
+	 * Creates an enumerator over all local subnets.
+	 *
+	 * Local subnets are subnets the host is directly connected to.
+	 *
+	 * @return				enumerator over host_t*, uint8_t
+	 */
+	enumerator_t *(*create_local_subnet_enumerator)(kernel_interface_t *this);
+
 	/**
 	 * Add a virtual IP to an interface.
 	 *

src/libcharon/kernel/kernel_net.h

@@ -118,6 +118,15 @@ struct kernel_net_t {
 	enumerator_t *(*create_address_enumerator) (kernel_net_t *this,
 												kernel_address_type_t which);
 
+	/**
+	 * Creates an enumerator over all local subnets.
+	 *
+	 * Local subnets are subnets the host is directly connected to.
+	 *
+	 * @return				enumerator over host_t*, uint8_t
+	 */
+	enumerator_t *(*create_local_subnet_enumerator)(kernel_net_t *this);
+
 	/**
 	 * Add a virtual IP to an interface.
 	 *