net: support both ipv4 and ipv6 gateways in sysconfig.

Previously, cloud-init would throw an exception if an interface had
both ipv4 and ipv6 addresses and a default gateway for each address
family.  This change allows cloud-init to correctly configure
interfaces in this situation.

LP: #1669504

2 files changed, 118 insertions, 9 deletions

diff --git a/cloudinit/net/sysconfig.py b/cloudinit/net/sysconfig.py
index 6e7739fb..06de660f 100644
--- a/cloudinit/net/sysconfig.py
+++ b/cloudinit/net/sysconfig.py
@@ -87,7 +87,8 @@ class Route(ConfigMap):
     def __init__(self, route_name, base_sysconf_dir):
         super(Route, self).__init__()
         self.last_idx = 1
-        self.has_set_default = False
+        self.has_set_default_ipv4 = False
+        self.has_set_default_ipv6 = False
         self._route_name = route_name
         self._base_sysconf_dir = base_sysconf_dir
 
@@ -95,7 +96,8 @@ class Route(ConfigMap):
         r = Route(self._route_name, self._base_sysconf_dir)
         r._conf = self._conf.copy()
         r.last_idx = self.last_idx
-        r.has_set_default = self.has_set_default
+        r.has_set_default_ipv4 = self.has_set_default_ipv4
+        r.has_set_default_ipv6 = self.has_set_default_ipv6
         return r
 
     @property
@@ -119,10 +121,10 @@ class NetInterface(ConfigMap):
         super(NetInterface, self).__init__()
         self.children = []
         self.routes = Route(iface_name, base_sysconf_dir)
-        self._kind = kind
+        self.kind = kind
+
         self._iface_name = iface_name
         self._conf['DEVICE'] = iface_name
-        self._conf['TYPE'] = self.iface_types[kind]
         self._base_sysconf_dir = base_sysconf_dir
 
     @property
@@ -140,6 +142,8 @@ class NetInterface(ConfigMap):
 
     @kind.setter
     def kind(self, kind):
+        if kind not in self.iface_types:
+            raise ValueError(kind)
         self._kind = kind
         self._conf['TYPE'] = self.iface_types[kind]
 
@@ -173,7 +177,7 @@ class Renderer(renderer.Renderer):
         ('BOOTPROTO', 'none'),
     ])
 
-    # If these keys exist, then there values will be used to form
+    # If these keys exist, then their values will be used to form
     # a BONDING_OPTS grouping; otherwise no grouping will be set.
     bond_tpl_opts = tuple([
         ('bond_mode', "mode=%s"),
@@ -199,6 +203,7 @@ class Renderer(renderer.Renderer):
     def _render_iface_shared(cls, iface, iface_cfg):
         for k, v in cls.iface_defaults:
             iface_cfg[k] = v
+
         for (old_key, new_key) in [('mac_address', 'HWADDR'), ('mtu', 'MTU')]:
             old_value = iface.get(old_key)
             if old_value is not None:
@@ -227,10 +232,20 @@ class Renderer(renderer.Renderer):
         if 'netmask' in subnet:
             iface_cfg['NETMASK'] = subnet['netmask']
         for route in subnet.get('routes', []):
+            if subnet.get('ipv6'):
+                gw_cfg = 'IPV6_DEFAULTGW'
+            else:
+                gw_cfg = 'GATEWAY'
+
             if _is_default_route(route):
-                if route_cfg.has_set_default:
-                    raise ValueError("Duplicate declaration of default"
-                                     " route found for interface '%s'"
+                if (
+                        (subnet.get('ipv4') and
+                         route_cfg.has_set_default_ipv4) or
+                        (subnet.get('ipv6') and
+                         route_cfg.has_set_default_ipv6)
+                ):
+                    raise ValueError("Duplicate declaration of default "
+                                     "route found for interface '%s'"
                                      % (iface_cfg.name))
                 # NOTE(harlowja): ipv6 and ipv4 default gateways
                 gw_key = 'GATEWAY0'
@@ -242,7 +257,7 @@ class Renderer(renderer.Renderer):
                 # also provided the default route?
                 iface_cfg['DEFROUTE'] = True
                 if 'gateway' in route:
-                    iface_cfg['GATEWAY'] = route['gateway']
+                    iface_cfg[gw_cfg] = route['gateway']
                 route_cfg.has_set_default = True
             else:
                 gw_key = 'GATEWAY%s' % route_cfg.last_idx
diff --git a/tests/unittests/test_net.py b/tests/unittests/test_net.py
index 4b03ff72..8d253109 100644
--- a/tests/unittests/test_net.py
+++ b/tests/unittests/test_net.py
@@ -248,6 +248,100 @@ nameserver 172.19.0.12
             ('etc/udev/rules.d/70-persistent-net.rules',
              "".join(['SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ',
                       'ATTR{address}=="fa:16:3e:ed:9a:59", NAME="eth0"\n']))]
+    },
+    {
+        'in_data': {
+            "services": [{"type": "dns", "address": "172.19.0.12"}],
+            "networks": [{
+                "network_id": "public-ipv4",
+                "type": "ipv4", "netmask": "255.255.252.0",
+                "link": "tap1a81968a-79",
+                "routes": [{
+                    "netmask": "0.0.0.0",
+                    "network": "0.0.0.0",
+                    "gateway": "172.19.3.254",
+                }],
+                "ip_address": "172.19.1.34", "id": "network0"
+            }, {
+                "network_id": "public-ipv6",
+                "type": "ipv6", "netmask": "",
+                "link": "tap1a81968a-79",
+                "routes": [
+                    {
+                        "gateway": "2001:DB8::1",
+                        "netmask": "::",
+                        "network": "::"
+                    }
+                ],
+                "ip_address": "2001:DB8::10", "id": "network1"
+            }],
+            "links": [
+                {
+                    "ethernet_mac_address": "fa:16:3e:ed:9a:59",
+                    "mtu": None, "type": "bridge", "id":
+                    "tap1a81968a-79",
+                    "vif_id": "1a81968a-797a-400f-8a80-567f997eb93f"
+                },
+            ],
+        },
+        'in_macs': {
+            'fa:16:3e:ed:9a:59': 'eth0',
+        },
+        'out_sysconfig': [
+            ('etc/sysconfig/network-scripts/ifcfg-eth0',
+             """
+# Created by cloud-init on instance boot automatically, do not edit.
+#
+BOOTPROTO=none
+DEVICE=eth0
+HWADDR=fa:16:3e:ed:9a:59
+NM_CONTROLLED=no
+ONBOOT=yes
+TYPE=Ethernet
+USERCTL=no
+""".lstrip()),
+            ('etc/sysconfig/network-scripts/ifcfg-eth0:0',
+             """
+# Created by cloud-init on instance boot automatically, do not edit.
+#
+BOOTPROTO=static
+DEFROUTE=yes
+DEVICE=eth0:0
+GATEWAY=172.19.3.254
+HWADDR=fa:16:3e:ed:9a:59
+IPADDR=172.19.1.34
+NETMASK=255.255.252.0
+NM_CONTROLLED=no
+ONBOOT=yes
+TYPE=Ethernet
+USERCTL=no
+""".lstrip()),
+            ('etc/sysconfig/network-scripts/ifcfg-eth0:1',
+             """
+# Created by cloud-init on instance boot automatically, do not edit.
+#
+BOOTPROTO=static
+DEFROUTE=yes
+DEVICE=eth0:1
+HWADDR=fa:16:3e:ed:9a:59
+IPV6ADDR=2001:DB8::10
+IPV6INIT=yes
+IPV6_DEFAULTGW=2001:DB8::1
+NETMASK=
+NM_CONTROLLED=no
+ONBOOT=yes
+TYPE=Ethernet
+USERCTL=no
+""".lstrip()),
+            ('etc/resolv.conf',
+             """
+; Created by cloud-init on instance boot automatically, do not edit.
+;
+nameserver 172.19.0.12
+""".lstrip()),
+            ('etc/udev/rules.d/70-persistent-net.rules',
+             "".join(['SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ',
+                      'ATTR{address}=="fa:16:3e:ed:9a:59", NAME="eth0"\n']))]
     }
 ]