Add flag for DEFROUTE=no in ifcfg files to ignore DHCP gateway

When multiple interfaces are configured with DHCP, and more than
one interface receives a gateway from the DHCP server(s), the
resulting default gateway on the system is unpredictable. This
change adds the "defroute" boolean to the configuration syntax
for os-net-config. Any interface type may be marked so that the
gateway received from the DHCP server will not be eligible as a
default gateway for the system. This only works for ifcfg files,
/etc/network/interfaces lacks an equivalent option.

Change-Id: Id775f3506b2ec60c9a2833efd49fb8319151c00d
Closes-Bug: 1449288

etc/os-net-config/samples/interface.json

@@ -7,7 +7,20 @@
         {
           "ip_netmask": "192.0.2.1/24"
         }
+      ],
+      "routes": [
+        {
+          "ip_netmask": "0.0.0.0/0",
+          "next_hop": "192.0.2.254",
+          "default": "true"
+        }
       ]
+    },
+    {
+      "type": "interface",
+      "name": "em2",
+      "use_dhcp": true,
+      "defroute": no
     }
   ]
 }

etc/os-net-config/samples/interface.yaml

@@ -6,3 +6,13 @@ network_config:
     addresses:
     -
       ip_netmask: 192.0.2.1/24
+    routes:
+      -
+        ip_netmask: 0.0.0.0/0
+        next_hop: 192.0.2.254
+        default: true
+  -
+    type: interface
+    name: em2
+    use_dhcp: true
+    defroute: no

os_net_config/impl_ifcfg.py

@@ -145,6 +145,8 @@ class IfcfgNetConfig(os_net_config.NetConfig):
             data += "HWADDR=%s\n" % base_opt.hwaddr
         if ovs_extra:
             data += "OVS_EXTRA=\"%s\"\n" % " -- ".join(ovs_extra)
+        if not base_opt.defroute:
+            data += "DEFROUTE=no\n"
         return data
 
     def _add_routes(self, interface_name, routes=[]):

os_net_config/objects.py

@@ -130,7 +130,7 @@ class _BaseOpts(object):
 
     def __init__(self, name, use_dhcp=False, use_dhcpv6=False, addresses=[],
                  routes=[], mtu=1500, primary=False, nic_mapping=None,
-                 persist_mapping=False):
+                 persist_mapping=False, defroute=True):
         numbered_nic_names = _numbered_nics(nic_mapping)
         self.hwaddr = None
         self.hwname = None
@@ -152,6 +152,7 @@ class _BaseOpts(object):
         self.addresses = addresses
         self.routes = routes
         self.primary = primary
+        self.defroute = defroute
         self.bridge_name = None  # internal
         self.ovs_port = False  # internal
         self.primary_interface_name = None  # internal
@@ -177,6 +178,8 @@ class _BaseOpts(object):
         use_dhcp = strutils.bool_from_string(str(json.get('use_dhcp', False)))
         use_dhcpv6 = strutils.bool_from_string(str(json.get('use_dhcpv6',
                                                False)))
+        defroute = strutils.bool_from_string(str(json.get('defroute',
+                                             True)))
         mtu = json.get('mtu', 1500)
         primary = strutils.bool_from_string(str(json.get('primary', False)))
         addresses = []
@@ -207,10 +210,10 @@ class _BaseOpts(object):
 
         if include_primary:
             return (use_dhcp, use_dhcpv6, addresses, routes, mtu, primary,
-                    nic_mapping, persist_mapping)
+                    nic_mapping, persist_mapping, defroute)
         else:
             return (use_dhcp, use_dhcpv6, addresses, routes, mtu,
-                    nic_mapping, persist_mapping)
+                    nic_mapping, persist_mapping, defroute)
 
 
 class Interface(_BaseOpts):
@@ -218,10 +221,10 @@ class Interface(_BaseOpts):
 
     def __init__(self, name, use_dhcp=False, use_dhcpv6=False, addresses=[],
                  routes=[], mtu=1500, primary=False, nic_mapping=None,
-                 persist_mapping=False):
+                 persist_mapping=False, defroute=True):
         super(Interface, self).__init__(name, use_dhcp, use_dhcpv6, addresses,
                                         routes, mtu, primary, nic_mapping,
-                                        persist_mapping)
+                                        persist_mapping, defroute)
 
     @staticmethod
     def from_json(json):
@@ -239,11 +242,11 @@ class Vlan(_BaseOpts):
 
     def __init__(self, device, vlan_id, use_dhcp=False, use_dhcpv6=False,
                  addresses=[], routes=[], mtu=1500, primary=False,
-                 nic_mapping=None, persist_mapping=False):
+                 nic_mapping=None, persist_mapping=False, defroute=True):
         name = 'vlan%i' % vlan_id
         super(Vlan, self).__init__(name, use_dhcp, use_dhcpv6, addresses,
                                    routes, mtu, primary, nic_mapping,
-                                   persist_mapping)
+                                   persist_mapping, defroute)
         self.vlan_id = int(vlan_id)
 
         numbered_nic_names = _numbered_nics(nic_mapping)
@@ -266,10 +269,11 @@ class OvsBridge(_BaseOpts):
 
     def __init__(self, name, use_dhcp=False, use_dhcpv6=False, addresses=[],
                  routes=[], mtu=1500, members=[], ovs_options=None,
-                 ovs_extra=[], nic_mapping=None, persist_mapping=False):
+                 ovs_extra=[], nic_mapping=None, persist_mapping=False,
+                 defroute=True):
         super(OvsBridge, self).__init__(name, use_dhcp, use_dhcpv6, addresses,
                                         routes, mtu, False, nic_mapping,
-                                        persist_mapping)
+                                        persist_mapping, defroute)
         self.members = members
         self.ovs_options = ovs_options
         self.ovs_extra = ovs_extra
@@ -289,7 +293,7 @@ class OvsBridge(_BaseOpts):
     def from_json(json):
         name = _get_required_field(json, 'name', 'OvsBridge')
         (use_dhcp, use_dhcpv6, addresses, routes, mtu, nic_mapping,
-         persist_mapping) = _BaseOpts.base_opts_from_json(
+         persist_mapping, defroute) = _BaseOpts.base_opts_from_json(
              json, include_primary=False)
         ovs_options = json.get('ovs_options')
         ovs_extra = json.get('ovs_extra', [])
@@ -309,7 +313,7 @@ class OvsBridge(_BaseOpts):
                          addresses=addresses, routes=routes, mtu=mtu,
                          members=members, ovs_options=ovs_options,
                          ovs_extra=ovs_extra, nic_mapping=nic_mapping,
-                         persist_mapping=persist_mapping)
+                         persist_mapping=persist_mapping, defroute=defroute)
 
 
 class OvsBond(_BaseOpts):
@@ -318,10 +322,10 @@ class OvsBond(_BaseOpts):
     def __init__(self, name, use_dhcp=False, use_dhcpv6=False, addresses=[],
                  routes=[], mtu=1500, primary=False, members=[],
                  ovs_options=None, ovs_extra=[], nic_mapping=None,
-                 persist_mapping=False):
+                 persist_mapping=False, defroute=True):
         super(OvsBond, self).__init__(name, use_dhcp, use_dhcpv6, addresses,
                                       routes, mtu, primary, nic_mapping,
-                                      persist_mapping)
+                                      persist_mapping, defroute)
         self.members = members
         self.ovs_options = ovs_options
         self.ovs_extra = ovs_extra
@@ -339,7 +343,7 @@ class OvsBond(_BaseOpts):
     def from_json(json):
         name = _get_required_field(json, 'name', 'OvsBond')
         (use_dhcp, use_dhcpv6, addresses, routes, mtu, nic_mapping,
-         persist_mapping) = _BaseOpts.base_opts_from_json(
+         persist_mapping, defroute) = _BaseOpts.base_opts_from_json(
              json, include_primary=False)
         ovs_options = json.get('ovs_options')
         ovs_extra = json.get('ovs_extra', [])
@@ -359,4 +363,4 @@ class OvsBond(_BaseOpts):
                        addresses=addresses, routes=routes, mtu=mtu,
                        members=members, ovs_options=ovs_options,
                        ovs_extra=ovs_extra, nic_mapping=nic_mapping,
-                       persist_mapping=persist_mapping)
+                       persist_mapping=persist_mapping, defroute=defroute)

os_net_config/tests/test_impl_ifcfg.py

@@ -260,6 +260,27 @@ BOOTPROTO=none
         self.assertEqual(_OVS_BOND_DHCP,
                          self.get_interface_config('bond0'))
 
+    def test_interface_defroute(self):
+        interface1 = objects.Interface('em1')
+        interface2 = objects.Interface('em2', defroute=False)
+        self.provider.add_interface(interface1)
+        self.provider.add_interface(interface2)
+        em1_config = """# This file is autogenerated by os-net-config
+DEVICE=em1
+ONBOOT=yes
+HOTPLUG=no
+BOOTPROTO=none
+"""
+        em2_config = """# This file is autogenerated by os-net-config
+DEVICE=em2
+ONBOOT=yes
+HOTPLUG=no
+BOOTPROTO=none
+DEFROUTE=no
+"""
+        self.assertEqual(em1_config, self.get_interface_config('em1'))
+        self.assertEqual(em2_config, self.get_interface_config('em2'))
+
 
 class TestIfcfgNetConfigApply(base.TestCase):
 

os_net_config/tests/test_objects.py

@@ -94,6 +94,20 @@ class TestInterface(base.TestCase):
         self.assertEqual("em1", interface.name)
         self.assertEqual(True, interface.use_dhcp)
 
+    def test_from_json_defroute(self):
+        data = '{"type": "interface", "name": "em1", "use_dhcp": true}'
+        interface1 = objects.object_from_json(json.loads(data))
+        data = """{
+"type": "interface",
+"name": "em1",
+"use_dhcp": true,
+"defroute": false
+}
+"""
+        interface2 = objects.object_from_json(json.loads(data))
+        self.assertEqual(True, interface1.defroute)
+        self.assertEqual(False, interface2.defroute)
+
     def test_from_json_dhcp_nic1(self):
         def dummy_numbered_nics(nic_mapping=None):
             return {"nic1": "em3"}