Fix for valid lifetime for slaac based address. (ARMmbed#2071)

Author: deepakvenugopal

source/6LoWPAN/ws/ws_bbr_api.c

@@ -366,7 +366,15 @@ static void ws_bbr_rpl_status_check(protocol_interface_info_entry_t *cur)
 
             if (configuration & BBR_GUA_C) {
                 // Add also global prefix and route to RPL
-                rpl_control_update_dodag_prefix(protocol_6lowpan_rpl_root_dodag, global_id, 64, t_flags, 0, 0, false);
+                uint32_t valid_lifetime;
+                if (t_flags & PIO_A) {
+                    valid_lifetime = 7200;
+                } else {
+                    valid_lifetime = 0;
+                }
+
+                rpl_control_update_dodag_prefix(protocol_6lowpan_rpl_root_dodag, global_id, 64, t_flags, valid_lifetime, valid_lifetime, false);
+
             }
             if (configuration & BBR_GUA_ROUTE) {
                 // Add also global prefix and route to RPL