net/sysconfig: Handle default route setup for dhcp configured NICs

When the network configuration has a default route configured and
another network device that is configured with dhcp, SUSE sysconfig
output should not accept the default route provided by the dhcp
server.

LP: #1812117

2 files changed, 55 insertions, 17 deletions

diff --git a/cloudinit/net/network_state.py b/cloudinit/net/network_state.py
index 539b76d8..4d19f562 100644
--- a/cloudinit/net/network_state.py
+++ b/cloudinit/net/network_state.py
@@ -148,6 +148,7 @@ class NetworkState(object):
         self._network_state = copy.deepcopy(network_state)
         self._version = version
         self.use_ipv6 = network_state.get('use_ipv6', False)
+        self._has_default_route = None
 
     @property
     def config(self):
@@ -157,14 +158,6 @@ class NetworkState(object):
     def version(self):
         return self._version
 
-    def iter_routes(self, filter_func=None):
-        for route in self._network_state.get('routes', []):
-            if filter_func is not None:
-                if filter_func(route):
-                    yield route
-            else:
-                yield route
-
     @property
     def dns_nameservers(self):
         try:
@@ -179,6 +172,12 @@ class NetworkState(object):
         except KeyError:
             return []
 
+    @property
+    def has_default_route(self):
+        if self._has_default_route is None:
+            self._has_default_route = self._maybe_has_default_route()
+        return self._has_default_route
+
     def iter_interfaces(self, filter_func=None):
         ifaces = self._network_state.get('interfaces', {})
         for iface in six.itervalues(ifaces):
@@ -188,6 +187,32 @@ class NetworkState(object):
                 if filter_func(iface):
                     yield iface
 
+    def iter_routes(self, filter_func=None):
+        for route in self._network_state.get('routes', []):
+            if filter_func is not None:
+                if filter_func(route):
+                    yield route
+            else:
+                yield route
+
+    def _maybe_has_default_route(self):
+        for route in self.iter_routes():
+            if self._is_default_route(route):
+                return True
+        for iface in self.iter_interfaces():
+            for subnet in iface.get('subnets', []):
+                for route in subnet.get('routes', []):
+                    if self._is_default_route(route):
+                        return True
+        return False
+
+    def _is_default_route(self, route):
+        default_nets = ('::', '0.0.0.0')
+        return (
+            route.get('prefix') == 0
+            and route.get('network') in default_nets
+            )
+
 
 @six.add_metaclass(CommandHandlerMeta)
 class NetworkStateInterpreter(object):
diff --git a/cloudinit/net/sysconfig.py b/cloudinit/net/sysconfig.py
index 19b3e60c..e59753d5 100644
--- a/cloudinit/net/sysconfig.py
+++ b/cloudinit/net/sysconfig.py
@@ -322,7 +322,7 @@ class Renderer(renderer.Renderer):
                 iface_cfg[new_key] = old_value
 
     @classmethod
-    def _render_subnets(cls, iface_cfg, subnets):
+    def _render_subnets(cls, iface_cfg, subnets, has_default_route):
         # setting base values
         iface_cfg['BOOTPROTO'] = 'none'
 
@@ -331,6 +331,7 @@ class Renderer(renderer.Renderer):
             mtu_key = 'MTU'
             subnet_type = subnet.get('type')
             if subnet_type == 'dhcp6':
+                # TODO need to set BOOTPROTO to dhcp6 on SUSE
                 iface_cfg['IPV6INIT'] = True
                 iface_cfg['DHCPV6C'] = True
             elif subnet_type in ['dhcp4', 'dhcp']:
@@ -375,9 +376,9 @@ class Renderer(renderer.Renderer):
         ipv6_index = -1
         for i, subnet in enumerate(subnets, start=len(iface_cfg.children)):
             subnet_type = subnet.get('type')
-            if subnet_type == 'dhcp6':
-                continue
-            elif subnet_type in ['dhcp4', 'dhcp']:
+            if subnet_type in ['dhcp', 'dhcp4', 'dhcp6']:
+                if has_default_route and iface_cfg['BOOTPROTO'] != 'none':
+                    iface_cfg['DHCLIENT_SET_DEFAULT_ROUTE'] = False
                 continue
             elif subnet_type == 'static':
                 if subnet_is_ipv6(subnet):
@@ -443,6 +444,8 @@ class Renderer(renderer.Renderer):
                     # TODO(harlowja): add validation that no other iface has
                     # also provided the default route?
                     iface_cfg['DEFROUTE'] = True
+                    if iface_cfg['BOOTPROTO'] in ('dhcp', 'dhcp4', 'dhcp6'):
+                        iface_cfg['DHCLIENT_SET_DEFAULT_ROUTE'] = True
                     if 'gateway' in route:
                         if is_ipv6 or is_ipv6_addr(route['gateway']):
                             iface_cfg['IPV6_DEFAULTGW'] = route['gateway']
@@ -493,7 +496,9 @@ class Renderer(renderer.Renderer):
             iface_cfg = iface_contents[iface_name]
             route_cfg = iface_cfg.routes
 
-            cls._render_subnets(iface_cfg, iface_subnets)
+            cls._render_subnets(
+                iface_cfg, iface_subnets, network_state.has_default_route
+            )
             cls._render_subnet_routes(iface_cfg, route_cfg, iface_subnets)
 
     @classmethod
@@ -518,7 +523,9 @@ class Renderer(renderer.Renderer):
 
             iface_subnets = iface.get("subnets", [])
             route_cfg = iface_cfg.routes
-            cls._render_subnets(iface_cfg, iface_subnets)
+            cls._render_subnets(
+                iface_cfg, iface_subnets, network_state.has_default_route
+            )
             cls._render_subnet_routes(iface_cfg, route_cfg, iface_subnets)
 
             # iter_interfaces on network-state is not sorted to produce
@@ -547,7 +554,9 @@ class Renderer(renderer.Renderer):
 
             iface_subnets = iface.get("subnets", [])
             route_cfg = iface_cfg.routes
-            cls._render_subnets(iface_cfg, iface_subnets)
+            cls._render_subnets(
+                iface_cfg, iface_subnets, network_state.has_default_route
+            )
             cls._render_subnet_routes(iface_cfg, route_cfg, iface_subnets)
 
     @staticmethod
@@ -608,7 +617,9 @@ class Renderer(renderer.Renderer):
 
             iface_subnets = iface.get("subnets", [])
             route_cfg = iface_cfg.routes
-            cls._render_subnets(iface_cfg, iface_subnets)
+            cls._render_subnets(
+                iface_cfg, iface_subnets, network_state.has_default_route
+            )
             cls._render_subnet_routes(iface_cfg, route_cfg, iface_subnets)
 
     @classmethod
@@ -620,7 +631,9 @@ class Renderer(renderer.Renderer):
             iface_cfg.kind = 'infiniband'
             iface_subnets = iface.get("subnets", [])
             route_cfg = iface_cfg.routes
-            cls._render_subnets(iface_cfg, iface_subnets)
+            cls._render_subnets(
+                iface_cfg, iface_subnets, network_state.has_default_route
+            )
             cls._render_subnet_routes(iface_cfg, route_cfg, iface_subnets)
 
     @classmethod