nm-cloud-setup: set preserve-external-ip flag during reapply

Externally added IP addresses/routes should be preserved by
nm-cloud-setup. This allows other tools to also configure the interface
and the Reapply() call from nm-cloud-setup would not interfere
with those tools.

https://bugzilla.redhat.com/show_bug.cgi?id=2132754

src/nm-cloud-setup/main.c

@@ -450,6 +450,7 @@ _config_one(GCancellable                      *sigterm_cancellable,
     gboolean                              version_id_changed;
     guint                                 try_count;
     gboolean                              any_changes = FALSE;
+    gboolean                              maybe_no_preserved_external_ip;
 
     g_main_context_iteration(NULL, FALSE);
 
@@ -538,10 +539,17 @@ try_again:
     /* we are about to call Reapply(). Even if that fails, it counts as if we changed something. */
     any_changes = TRUE;
 
+    /* "preserve-external-ip" flag was only introduced in 1.41.6 (but maybe backported!).
+     * If we run 1.41.6+, we are sure that it's gonna work. Otherwise, we take into account
+     * that the call might fail due to the invalid flag and we retry. */
+    maybe_no_preserved_external_ip =
+        (nmc_client_has_version_info_v(nmc) < NM_ENCODE_VERSION(1, 41, 6));
+
     if (!nmcs_device_reapply(device,
                              sigterm_cancellable,
                              applied_connection,
                              applied_version_id,
+                             maybe_no_preserved_external_ip,
                              &version_id_changed,
                              &error)) {
         if (version_id_changed && try_count < 5) {

src/nm-cloud-setup/nm-cloud-setup-utils.c

@@ -822,6 +822,7 @@ nmcs_device_reapply(NMDevice     *device,
                     GCancellable *sigterm_cancellable,
                     NMConnection *connection,
                     guint64       version_id,
+                    gboolean      maybe_no_preserved_external_ip,
                     gboolean     *out_version_id_changed,
                     GError      **error)
 {
@@ -829,11 +830,13 @@ nmcs_device_reapply(NMDevice     *device,
     DeviceReapplyData                  data      = {
                               .main_loop = main_loop,
     };
+    NMDeviceReapplyFlags reapply_flags = NM_DEVICE_REAPPLY_FLAGS_PRESERVE_EXTERNAL_IP;
 
+again:
     nm_device_reapply_async(device,
                             connection,
                             version_id,
-                            0,
+                            reapply_flags,
                             sigterm_cancellable,
                             _nmcs_device_reapply_cb,
                             &data);
@@ -841,6 +844,17 @@ nmcs_device_reapply(NMDevice     *device,
     g_main_loop_run(main_loop);
 
     if (data.error) {
+        if (maybe_no_preserved_external_ip
+            && reapply_flags == NM_DEVICE_REAPPLY_FLAGS_PRESERVE_EXTERNAL_IP
+            && nm_g_error_matches(data.error, NM_DEVICE_ERROR, NM_DEVICE_ERROR_FAILED)) {
+            /* Hm? Maybe we running against an older version of NetworkManager that
+             * doesn't support "preserve-external-ip" flags? Retry without the flag.
+             *
+             * Note that recent version would reject invalid flags with NM_DEVICE_ERROR_INVALID_ARGUMENT,
+             * but we want to detect old daemon versions here. */
+            reapply_flags = NM_DEVICE_REAPPLY_FLAGS_NONE;
+            goto again;
+        }
         NM_SET_OUT(
             out_version_id_changed,
             g_error_matches(data.error, NM_DEVICE_ERROR, NM_DEVICE_ERROR_VERSION_ID_MISMATCH));

src/nm-cloud-setup/nm-cloud-setup-utils.h

@@ -136,6 +136,7 @@ gboolean nmcs_device_reapply(NMDevice     *device,
                              GCancellable *sigterm_cancellable,
                              NMConnection *connection,
                              guint64       version_id,
+                             gboolean      maybe_no_preserved_external_ip,
                              gboolean     *out_version_id_changed,
                              GError      **error);