core/connection: ensure wired settings are around for bridges

Bridges are wired ethernet bridges, it makes sense for them to have
wired ethernet settings.

Ensuring they always exist makes reapplying the MTU changes more
convenient. The MTU for bridges is taken from wired settings, making it
impossible to change and reapply it for connections that lack them
(as reapply doesn't really cope well with addition and removal of
settings).

https://bugzilla.redhat.com/show_bug.cgi?id=2076131
https://gitlab.freedesktop.org/NetworkManager/NetworkManager/-/merge_requests/1208

3 files changed, 16 insertions, 1 deletions

diff --git a/src/core/settings/plugins/keyfile/tests/test-keyfile-settings.c b/src/core/settings/plugins/keyfile/tests/test-keyfile-settings.c
index 11a8e4169c..b24acc45af 100644
--- a/src/core/settings/plugins/keyfile/tests/test-keyfile-settings.c
+++ b/src/core/settings/plugins/keyfile/tests/test-keyfile-settings.c
@@ -1924,6 +1924,7 @@ test_write_bridge_main(void)
     gs_unref_object NMConnection *connection = NULL;
     NMSettingConnection          *s_con;
     NMSettingBridge              *s_bridge;
+    NMSettingWired               *s_wired;
     NMSettingIPConfig            *s_ip4;
     NMSettingIPConfig            *s_ip6;
 
@@ -1953,6 +1954,11 @@ test_write_bridge_main(void)
     g_assert(s_bridge);
     nm_connection_add_setting(connection, NM_SETTING(s_bridge));
 
+    /* Ethernet setting */
+    s_wired = (NMSettingWired *) nm_setting_wired_new();
+    g_assert(s_wired);
+    nm_connection_add_setting(connection, NM_SETTING(s_wired));
+
     /* IP4 setting */
     s_ip4 = (NMSettingIPConfig *) nm_setting_ip4_config_new();
     g_assert(s_ip4);
diff --git a/src/libnm-core-impl/nm-connection.c b/src/libnm-core-impl/nm-connection.c
index 5f1a157a65..aed4be2113 100644
--- a/src/libnm-core-impl/nm-connection.c
+++ b/src/libnm-core-impl/nm-connection.c
@@ -1708,7 +1708,7 @@ _normalize_required_settings(NMConnection *self)
     NMSetting          *s_bridge;
     gboolean            changed = FALSE;
 
-    if (nm_connection_get_setting_vlan(self)) {
+    if (nm_connection_get_setting_vlan(self) || nm_connection_get_setting_bridge(self)) {
         if (!nm_connection_get_setting_wired(self)) {
             nm_connection_add_setting(self, nm_setting_wired_new());
             changed = TRUE;
diff --git a/src/libnm-core-impl/nm-setting-bridge.c b/src/libnm-core-impl/nm-setting-bridge.c
index fab6e4762e..39a3fb6017 100644
--- a/src/libnm-core-impl/nm-setting-bridge.c
+++ b/src/libnm-core-impl/nm-setting-bridge.c
@@ -1311,6 +1311,15 @@ verify(NMSetting *setting, NMConnection *connection, GError **error)
                                            NM_SETTING_BRIDGE_VLANS))
         return NM_SETTING_VERIFY_NORMALIZABLE;
 
+    if (connection && !nm_connection_get_setting_wired(connection)) {
+        g_set_error_literal(error,
+                            NM_CONNECTION_ERROR,
+                            NM_CONNECTION_ERROR_SETTING_NOT_FOUND,
+                            _("bridge connection should have a ethernet setting as well"));
+        g_prefix_error(error, "%s: ", NM_SETTING_BRIDGE_SETTING_NAME);
+        return NM_SETTING_VERIFY_NORMALIZABLE;
+    }
+
     return TRUE;
 }