gnrc_ndp: don't don't let addresses timeout

This is a temporary quick-fix for #5122 to not have GUAs removed on an
interface.
It solves the issue by both not letting the registration run out on the router
and by not letting the lifetime of an auto-configured address expire.

sys/net/gnrc/network_layer/ipv6/gnrc_ipv6.c

@@ -255,11 +255,13 @@ static void *_event_loop(void *args)
                 ((gnrc_ipv6_nc_t *)msg.content.ptr)->flags &= ~GNRC_IPV6_NC_IS_ROUTER;
                 break;
 
-            case GNRC_NDP_MSG_ADDR_TIMEOUT:
-                DEBUG("ipv6: Router advertisement timer event received\n");
-                gnrc_ipv6_netif_remove_addr(KERNEL_PID_UNDEF,
-                                            (ipv6_addr_t *)msg.content.ptr);
-                break;
+            /* XXX reactivate when https://github.com/RIOT-OS/RIOT/issues/5122 is
+             * solved properly */
+            /* case GNRC_NDP_MSG_ADDR_TIMEOUT: */
+            /*     DEBUG("ipv6: Router advertisement timer event received\n"); */
+            /*     gnrc_ipv6_netif_remove_addr(KERNEL_PID_UNDEF, */
+            /*                                 (ipv6_addr_t *)msg.content.ptr); */
+            /*     break; */
 
             case GNRC_NDP_MSG_NBR_SOL_RETRANS:
                 DEBUG("ipv6: Neigbor solicitation retransmission timer event received\n");
@@ -310,10 +312,12 @@ static void *_event_loop(void *args)
                 gnrc_sixlowpan_nd_router_abr_remove(
                         (gnrc_sixlowpan_nd_router_abr_t *)msg.content.ptr);
                 break;
-            case GNRC_SIXLOWPAN_ND_MSG_AR_TIMEOUT:
-                DEBUG("ipv6: address registration timeout received\n");
-                gnrc_sixlowpan_nd_router_gc_nc((gnrc_ipv6_nc_t *)msg.content.ptr);
-                break;
+            /* XXX reactivate when https://github.com/RIOT-OS/RIOT/issues/5122 is
+             * solved properly */
+            /* case GNRC_SIXLOWPAN_ND_MSG_AR_TIMEOUT: */
+            /*     DEBUG("ipv6: address registration timeout received\n"); */
+            /*     gnrc_sixlowpan_nd_router_gc_nc((gnrc_ipv6_nc_t *)msg.content.ptr); */
+            /*     break; */
             case GNRC_NDP_MSG_RTR_ADV_SIXLOWPAN_DELAY:
                 DEBUG("ipv6: Delayed router advertisement event received\n");
                 gnrc_ipv6_nc_t *nc_entry = (gnrc_ipv6_nc_t *)msg.content.ptr;