route: workaround for removing IPv6 default gateway

Due to NM bug [1], Nmstate is not removing IPv6 default gateway. In
order to workaround this, Nmstate is deactivating first the interface if
an IPv6 route has been removed.

Integration test added.

[1] https://bugzilla.redhat.com/1837254

Signed-off-by: Fernando Fernandez Mancera <ffmancera@riseup.net>

libnmstate/nm/profile.py

@@ -49,6 +49,7 @@ from .translator import Api2Nm
 IMPORT_NM_DEV_TIMEOUT = 5
 IMPORT_NM_DEV_RETRY_INTERNAL = 0.5
 FALLBACK_CHECKER_INTERNAL = 15
+IPV6_ROUTE_REMOVED = "_ipv6_route_removed"
 
 
 class NmProfile:
@@ -162,6 +163,11 @@ class NmProfile:
             elif self._iface.is_virtual and self._nm_dev:
                 self._add_action(NmProfile.ACTION_DELETE_DEVICE)
 
+        if self._iface.raw.get(IPV6_ROUTE_REMOVED):
+            # This is a workaround for NM bug:
+            # https://bugzilla.redhat.com/1837254
+            self._add_action(NmProfile.ACTION_DEACTIVATE_FIRST)
+
         if self._iface.is_controller and self._iface.is_up:
             if self._iface.controller:
                 self._add_action(NmProfile.ACTION_OTHER_MASTER)

libnmstate/route.py

@@ -33,6 +33,9 @@ from .state import StateEntry
 from .state import state_match
 
 
+IPV6_ROUTE_REMOVED = "_ipv6_route_removed"
+
+
 class RouteEntry(StateEntry):
     IPV4_DEFAULT_GATEWAY_DESTINATION = "0.0.0.0/0"
     IPV6_DEFAULT_GATEWAY_DESTINATION = "::/0"
@@ -211,6 +214,16 @@ class RouteState:
             for route in route_set:
                 if not rt.match(route):
                     new_routes.add(route)
+                if route.is_ipv6:
+                    # The routes match and therefore it is being removed.
+                    # Nmstate will check if it is an IPv6 route and if so,
+                    # marking the interface as deactivate first.
+                    #
+                    # This is a workaround for NM bug:
+                    # https://bugzilla.redhat.com/1837254
+                    ifaces.all_kernel_ifaces[iface_name].raw[
+                        IPV6_ROUTE_REMOVED
+                    ] = True
             if new_routes != route_set:
                 self._routes[iface_name] = new_routes
 

tests/integration/route_test.py

@@ -31,6 +31,7 @@ from libnmstate.schema import InterfaceType
 from libnmstate.schema import Route
 from libnmstate.schema import RouteRule
 
+from .testlib import cmdlib
 from .testlib import iprule
 
 IPV4_ADDRESS1 = "192.0.2.251"
@@ -45,6 +46,8 @@ IPV4_DNS_NAMESERVER = "8.8.8.8"
 IPV6_DNS_NAMESERVER = "2001:4860:4860::8888"
 DNS_SEARCHES = ["example.org", "example.com"]
 
+IPV6_GATEWAY1 = "2001:db8:1::f"
+IPV6_GATEWAY2 = "2001:db8:1::e"
 
 ETH1_INTERFACE_STATE = {
     Interface.NAME: "eth1",
@@ -290,14 +293,14 @@ def _get_ipv6_gateways():
         {
             Route.DESTINATION: "::/0",
             Route.METRIC: 103,
-            Route.NEXT_HOP_ADDRESS: "2001:db8:1::f",
+            Route.NEXT_HOP_ADDRESS: IPV6_GATEWAY1,
             Route.NEXT_HOP_INTERFACE: "eth1",
             Route.TABLE_ID: 254,
         },
         {
             Route.DESTINATION: "::/0",
             Route.METRIC: 101,
-            Route.NEXT_HOP_ADDRESS: "2001:db8:1::e",
+            Route.NEXT_HOP_ADDRESS: IPV6_GATEWAY2,
             Route.NEXT_HOP_INTERFACE: "eth1",
             Route.TABLE_ID: 254,
         },
@@ -502,6 +505,44 @@ def test_apply_empty_state_preserve_routes(eth1_static_gateway_dns):
     assert current_state[DNS.KEY][DNS.CONFIG] == state[DNS.KEY][DNS.CONFIG]
 
 
+def _get_routes_from_iproute():
+    _, out, _ = cmdlib.exec_cmd("ip -6 route".split(), check=True)
+    return out
+
+
+def test_remove_default_ipv6_gateway_and_revert():
+    gateway1 = {
+        Route.DESTINATION: "::/0",
+        Route.METRIC: -1,
+        Route.NEXT_HOP_ADDRESS: IPV6_GATEWAY1,
+        Route.NEXT_HOP_INTERFACE: "eth1",
+        Route.TABLE_ID: 0,
+    }
+    gateway2 = {
+        Route.DESTINATION: "::/0",
+        Route.METRIC: -1,
+        Route.NEXT_HOP_ADDRESS: IPV6_GATEWAY2,
+        Route.NEXT_HOP_INTERFACE: "eth1",
+        Route.TABLE_ID: 0,
+    }
+
+    eth1 = copy.deepcopy(ETH1_INTERFACE_STATE)
+    d_state = {Interface.KEY: [eth1], Route.KEY: {Route.CONFIG: [gateway1]}}
+    libnmstate.apply(d_state)
+
+    gateway1[Route.STATE] = Route.STATE_ABSENT
+    d_state[Route.KEY][Route.CONFIG] = [gateway1, gateway2]
+    libnmstate.apply(d_state)
+
+    gateway1.pop(Route.STATE)
+    gateway2[Route.STATE] = Route.STATE_ABSENT
+    libnmstate.apply(d_state)
+
+    routes_output = _get_routes_from_iproute()
+    assert IPV6_GATEWAY1 in routes_output
+    assert IPV6_GATEWAY2 not in routes_output
+
+
 @pytest.fixture(scope="function")
 def route_rule_test_env(eth1_static_gateway_dns):
     yield eth1_static_gateway_dns