DHCP relay and Renew update

Added API for get DHCPv6 Relay sserver Global address.

Use Relay agent Global Address for DHCPv6 renew if service is enabled. Fix routing issue if parent is updated.

Change-Id: I1f0a8e69629875784907a2746dea5896f890927d

nanostack/dhcp_service_api.h

@@ -133,6 +133,16 @@ uint16_t dhcp_service_init(int8_t interface_id, dhcp_instance_type_e instance_ty
 */
 void dhcp_service_relay_instance_enable(uint16_t instance, uint8_t *server_address);
 
+/**
+* \brief Get DHCPv6 Relay Agent address pointer.
+*
+* \param instance The instance ID of the registered server.
+*
+* \return NULL when address is not available
+* {
+*/
+uint8_t *dhcp_service_relay_global_addres_get(uint16_t instance);
+
 
 /**
 * \brief Deletes a server instance.

source/DHCPv6_client/dhcpv6_client_service.c

@@ -350,7 +350,12 @@ void dhcpv6_renew(protocol_interface_info_entry_t *interface, if_address_entry_t
     serverLink.linkType = srv_data_ptr->serverLinkType;
     libdhcpv6_generic_nontemporal_address_message_write(payload_ptr, &packetReq, &nonTemporalAddress, &serverLink);
     // send solicit
-    srv_data_ptr->transActionId = dhcp_service_send_req(dhcp_client.service_instance, 0, srv_data_ptr, srv_data_ptr->server_address, payload_ptr, payload_len, dhcp_solicit_resp_cb);
+    uint8_t *server_address = dhcp_service_relay_global_addres_get(dhcp_client.relay_instance);
+    if (!server_address) {
+        server_address = srv_data_ptr->server_address;
+    }
+
+    srv_data_ptr->transActionId = dhcp_service_send_req(dhcp_client.service_instance, 0, srv_data_ptr, server_address, payload_ptr, payload_len, dhcp_solicit_resp_cb);
     if (srv_data_ptr->transActionId == 0) {
         ns_dyn_mem_free(payload_ptr);
         addr->state_timer = 200; //Retry after 20 seconds

source/libDHCPv6/dhcp_service_api.c

@@ -616,6 +616,16 @@ void dhcp_service_relay_instance_enable(uint16_t instance, uint8_t *server_addre
     }
 }
 
+uint8_t *dhcp_service_relay_global_addres_get(uint16_t instance)
+{
+    relay_instance_t *realay_srv = dhcp_service_relay_find(instance);
+    if (!realay_srv || !realay_srv->relay_activated) {
+        return NULL;
+    }
+
+    return realay_srv->server_address;
+}
+
 void dhcp_service_delete(uint16_t instance)
 {
     server_instance_t *srv_ptr;

test/nanostack/unittest/stub/dhcp_service_api_stub.c

@@ -174,3 +174,8 @@ void dhcp_service_relay_instance_enable(uint16_t instance, uint8_t *server_addre
 {
 
 }
+
+uint8_t  *dhcp_service_relay_global_addres_get(uint16_t instance)
+{
+    return NULL;
+}