From 2968a5717cf59fb948d65caf93c2da74b8820507 Mon Sep 17 00:00:00 2001
From: Stefan Agner <stefan@agner.ch>
Date: Wed, 9 Oct 2024 20:16:36 +0200
Subject: [PATCH] Update DNS plug-in on network change (#5331)

* Update DNS plug-in on network change

Restart the DNS plug-in when the primary network changes network
changes. This makes sure any potential host OS DNS configuration
changes get picked up by the DNS plug-in as well.

* Add a test case

---------

Co-authored-by: Mike Degatano <michael.degatano@gmail.com>
---
 supervisor/host/network.py      | 11 +++++++++++
 tests/host/test_connectivity.py | 18 ++++++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/supervisor/host/network.py b/supervisor/host/network.py
index ef3aa3dea..5058c3168 100644
--- a/supervisor/host/network.py
+++ b/supervisor/host/network.py
@@ -10,7 +10,9 @@ from ..coresys import CoreSys, CoreSysAttributes
 from ..dbus.const import (
     DBUS_ATTR_CONNECTION_ENABLED,
     DBUS_ATTR_CONNECTIVITY,
+    DBUS_ATTR_PRIMARY_CONNECTION,
     DBUS_IFACE_NM,
+    DBUS_OBJECT_BASE,
     DBUS_SIGNAL_NM_CONNECTION_ACTIVE_CHANGED,
     ConnectionStateType,
     ConnectivityState,
@@ -148,6 +150,15 @@ class NetworkManager(CoreSysAttributes):
         connectivity_check: bool | None = changed.get(DBUS_ATTR_CONNECTION_ENABLED)
         connectivity: bool | None = changed.get(DBUS_ATTR_CONNECTIVITY)
 
+        # This potentially updated the DNS configuration. Make sure the DNS plug-in
+        # picks up the latest settings.
+        if (
+            DBUS_ATTR_PRIMARY_CONNECTION in changed
+            and changed[DBUS_ATTR_PRIMARY_CONNECTION]
+            and changed[DBUS_ATTR_PRIMARY_CONNECTION] != DBUS_OBJECT_BASE
+        ):
+            await self.sys_plugins.dns.restart()
+
         if (
             connectivity_check is True
             or DBUS_ATTR_CONNECTION_ENABLED in invalidated
diff --git a/tests/host/test_connectivity.py b/tests/host/test_connectivity.py
index 72984be06..77e3c7483 100644
--- a/tests/host/test_connectivity.py
+++ b/tests/host/test_connectivity.py
@@ -7,6 +7,7 @@ from unittest.mock import PropertyMock, patch
 import pytest
 
 from supervisor.coresys import CoreSys
+from supervisor.plugins.dns import PluginDns
 
 from tests.dbus_service_mocks.network_manager import (
     NetworkManager as NetworkManagerService,
@@ -84,3 +85,20 @@ async def test_connectivity_events(coresys: CoreSys, force: bool):
                     },
                 }
             )
+
+
+async def test_dns_restart_on_connection_change(
+    coresys: CoreSys, network_manager_service: NetworkManagerService
+):
+    """Test dns plugin is restarted when primary connection changes."""
+    await coresys.host.network.load()
+    with patch.object(PluginDns, "restart") as restart:
+        network_manager_service.emit_properties_changed({"PrimaryConnection": "/"})
+        await network_manager_service.ping()
+        restart.assert_not_called()
+
+        network_manager_service.emit_properties_changed(
+            {"PrimaryConnection": "/org/freedesktop/NetworkManager/ActiveConnection/2"}
+        )
+        await network_manager_service.ping()
+        restart.assert_called_once()