Enabled roaming and routing between multiple Wi-SUN BR

Send NA to backbone when new devices join to flush caches of other BR
Use autonomous addressing to make devices to have non conflicting address
Set specific lifetime for DHCP addresses to notice device roaming or loss

Author: Mika Tervonen

source/6LoWPAN/ws/ws_bbr_api.c

@@ -216,6 +216,31 @@ static int ws_bbr_dodag_get(protocol_interface_info_entry_t *cur, uint8_t *stati
     memcpy(dodag_id_ptr, global_address, 16);
     return 0;
 }
+static void wisun_bbr_na_send(int8_t interface_id, const uint8_t target[static 16])
+{
+    protocol_interface_info_entry_t *cur = protocol_stack_interface_info_get_by_id(interface_id);
+    if (!cur) {
+        return;
+    }
+
+    buffer_t *buffer = icmpv6_build_na(cur, false, true, true, target, NULL, ADDR_UNSPECIFIED);
+    protocol_push(buffer);
+    return;
+
+}
+
+static bool wisun_dhcp_address_add_cb(int8_t interfaceId, dhcp_address_cache_update_t *address_info, void *route_src)
+{
+    (void)route_src;
+    protocol_interface_info_entry_t *curPtr = protocol_stack_interface_info_get_by_id(interfaceId);
+    if (!curPtr) {
+        return false;
+    }
+
+    // When address is allocated we send NA to backbone to notify the new address and flush from other BBRs
+    wisun_bbr_na_send(backbone_interface_id, address_info->allocatedAddress);
+    return true;
+}
 
 
 static void ws_bbr_rpl_status_check(protocol_interface_info_entry_t *cur)
@@ -264,8 +289,11 @@ static void ws_bbr_rpl_status_check(protocol_interface_info_entry_t *cur)
                 tr_error("DHCPv6 Server create fail");
                 return;
             }
+            DHCPv6_server_service_callback_set(cur->id, global_id, NULL, wisun_dhcp_address_add_cb);
+
+            DHCPv6_server_service_set_address_autonous_flag(cur->id, global_id, true);
+            DHCPv6_server_service_set_address_validlifetime(cur->id, global_id, 7200);
 
-            DHCPv6_server_service_set_address_autonous_flag(cur->id, global_id, false);
             tr_info("RPL GUA activate %s", trace_ipv6(global_id));
             ws_dhcp_client_address_request(cur, global_id, ll);