[fix] Ignore duplicate IP addresses in network config

Some valid OpenWrt configurations may result in the agent seeing
two times the same IP address and generating an invalid
NetJSON NetworkMonitoring object, this patch fixes this issue.

Author: pandafy

openwisp-monitoring/files/lib/openwisp-monitoring/interfaces.lua

@@ -104,14 +104,18 @@ function interfaces.get_addresses(name)
   for _, interface in pairs(interface_list) do
     if interface['l3_device'] == name then
       for _, address in pairs(interface['ipv4-address']) do
-        table.insert(addresses_list, address['address'])
-        local new_address = interfaces.new_address_array(address, interface, 'ipv4')
-        table.insert(addresses, new_address)
+        if not utils.has_value(addresses_list, address['address']) then
+          table.insert(addresses_list, address['address'])
+          local new_address = interfaces.new_address_array(address, interface, 'ipv4')
+          table.insert(addresses, new_address)
+        end
       end
       for _, address in pairs(interface['ipv6-address']) do
-        table.insert(addresses_list, address['address'])
-        local new_address = interfaces.new_address_array(address, interface, 'ipv6')
-        table.insert(addresses, new_address)
+        if not utils.has_value(addresses_list, address['address']) then
+          table.insert(addresses_list, address['address'])
+          local new_address = interfaces.new_address_array(address, interface, 'ipv6')
+          table.insert(addresses, new_address)
+        end
       end
     end
   end

openwisp-monitoring/tests/test_files/interface_data.lua

@@ -80,6 +80,40 @@ test_data.interface_data = {
       up = true,
       updated = {"addresses"},
       uptime = 773875
+    },{
+      autostart = true,
+      available = true,
+      data = {leasetime = 600},
+      delegation = true,
+      device = "eth1",
+      ["dns-search"] = {},
+      ["dns-server"] = {"10.0.2.1"},
+      dns_metric = 0,
+      dynamic = false,
+      inactive = {
+        ["dns-search"] = {},
+        ["dns-server"] = {},
+        ["ipv4-address"] = {},
+        ["ipv6-address"] = {},
+        neighbors = {},
+        route = {}
+      },
+      interface = "mgmnt",
+      ["ipv4-address"] = {{address = "10.0.2.4", mask = 24}},
+      ["ipv6-address"] = {{address = "2001:0db8:85a3:0000:0000:8a2e:0370:7334"}},
+      ["ipv6-prefix"] = {},
+      ["ipv6-prefix-assignment"] = {},
+      l3_device = "eth1",
+      metric = 0,
+      neighbors = {},
+      pending = false,
+      proto = "dhcp",
+      route = {
+        {mask = 0, nexthop = "10.0.2.1", source = "10.0.2.4/32", target = "0.0.0.0"}
+      },
+      up = true,
+      updated = {"addresses", "routes", "data"},
+      uptime = 132
     }, {
       autostart = true,
       available = true,