[OpenWrt] Avoid adding dns and dns_search if proto is none

Avoid adding "dns" and "dns_search" config options for interfaces
that have "proto" set to "none".

netjsonconfig/backends/openwrt/renderers.py

@@ -184,8 +184,8 @@ def __get_dns_servers(self, uci, address):
         # allow override
         if 'dns' in uci:
             return uci['dns']
-        # ignore if using DHCP
-        if address['proto'] == 'dhcp':
+        # ignore if using DHCP or if "proto" is none
+        if address['proto'] in ['dhcp', 'none']:
             return None
         # general setting
         dns = self.config.get('dns_servers', None)
@@ -196,6 +196,9 @@ def __get_dns_search(self, uci, address):
         # allow override
         if 'dns_search' in uci:
             return uci['dns_search']
+        # ignore if "proto" is none
+        if address['proto'] == 'none':
+            return None
         # general setting
         dns_search = self.config.get('dns_search', None)
         if dns_search:

tests/openwrt/test_network.py

@@ -585,6 +585,25 @@ def test_dns_dhcpv6_ignored(self):
 """)
         self.assertEqual(o.render(), expected)
 
+    def test_dhcp_ignored_proto_none(self):
+        o = OpenWrt({
+            "interfaces": [
+                {
+                    "name": "eth0",
+                    "type": "ethernet",
+                }
+            ],
+            "dns_servers": ["10.11.12.13", "8.8.8.8"],
+            "dns_search": ["netjson.org", "openwisp.org"],
+        })
+        expected = self._tabs("""package network
+
+config interface 'eth0'
+    option ifname 'eth0'
+    option proto 'none'
+""")
+        self.assertEqual(o.render(), expected)
+
     def test_rules(self):
         o = OpenWrt({
             "ip_rules": [