dns: cleanup RequestItem and track ifindex and self parameter

We will need these changes next:

- add "self" and "ifindex" fields to RequestItem struct. We will
  pass on these structs are user-data for the callbacks, so that
  we afterwards know which request completed.

- add DBUS_OP_SET_LINK_DEFAULT_ROUTE global variable. We don't
  clone the "operation" string but use string literals. However,
  string literals are not guaranteed to be deduplicated, so we
  should only compare them with strcmp(). The static variable
  avoids this: we can use pointer equality to compare it.
  This will be used next.

1 files changed, 43 insertions, 28 deletions

diff --git a/src/dns/nm-dns-systemd-resolved.c b/src/dns/nm-dns-systemd-resolved.c
index d1756a573b..b4aab861ef 100644
--- a/src/dns/nm-dns-systemd-resolved.c
+++ b/src/dns/nm-dns-systemd-resolved.c
@@ -34,6 +34,9 @@
 #define SYSTEMD_RESOLVED_MANAGER_IFACE "org.freedesktop.resolve1.Manager"
 #define SYSTEMD_RESOLVED_DBUS_PATH     "/org/freedesktop/resolve1"
 
+/* define a variable, so that we can compare the operation with pointer equality. */
+static const char *const DBUS_OP_SET_LINK_DEFAULT_ROUTE = "SetLinkDefaultRoute";
+
 /*****************************************************************************/
 
 typedef struct {
@@ -42,9 +45,11 @@ typedef struct {
 } InterfaceConfig;
 
 typedef struct {
-    CList       request_queue_lst;
-    const char *operation;
-    GVariant *  argument;
+    CList                 request_queue_lst;
+    const char *          operation;
+    GVariant *            argument;
+    NMDnsSystemdResolved *self;
+    int                   ifindex;
 } RequestItem;
 
 /*****************************************************************************/
@@ -88,18 +93,26 @@ _request_item_free(RequestItem *request_item)
 {
     c_list_unlink_stale(&request_item->request_queue_lst);
     g_variant_unref(request_item->argument);
-    g_slice_free(RequestItem, request_item);
+    nm_g_slice_free(request_item);
 }
 
 static void
-_request_item_append(CList *request_queue_lst_head, const char *operation, GVariant *argument)
+_request_item_append(NMDnsSystemdResolved *self,
+                     const char *          operation,
+                     int                   ifindex,
+                     GVariant *            argument)
 {
-    RequestItem *request_item;
+    NMDnsSystemdResolvedPrivate *priv = NM_DNS_SYSTEMD_RESOLVED_GET_PRIVATE(self);
+    RequestItem *                request_item;
 
-    request_item            = g_slice_new(RequestItem);
-    request_item->operation = operation;
-    request_item->argument  = g_variant_ref_sink(argument);
-    c_list_link_tail(request_queue_lst_head, &request_item->request_queue_lst);
+    request_item  = g_slice_new(RequestItem);
+    *request_item = (RequestItem){
+        .operation = operation,
+        .argument  = g_variant_ref_sink(argument),
+        .self      = self,
+        .ifindex   = ifindex,
+    };
+    c_list_link_tail(&priv->request_queue_lst_head, &request_item->request_queue_lst);
 }
 
 /*****************************************************************************/
@@ -116,13 +129,14 @@ call_done(GObject *source, GAsyncResult *r, gpointer user_data)
 {
     gs_unref_variant GVariant *v       = NULL;
     gs_free_error GError *       error = NULL;
-    NMDnsSystemdResolved *       self  = (NMDnsSystemdResolved *) user_data;
+    NMDnsSystemdResolved *       self;
     NMDnsSystemdResolvedPrivate *priv;
 
     v = g_dbus_connection_call_finish(G_DBUS_CONNECTION(source), r, &error);
-    if (!v && g_error_matches(error, G_IO_ERROR, G_IO_ERROR_CANCELLED))
+    if (nm_utils_error_is_cancelled(error))
         return;
 
+    self = user_data;
     priv = NM_DNS_SYSTEMD_RESOLVED_GET_PRIVATE(self);
 
     if (!v) {
@@ -198,14 +212,14 @@ free_pending_updates(NMDnsSystemdResolved *self)
 static gboolean
 prepare_one_interface(NMDnsSystemdResolved *self, InterfaceConfig *ic)
 {
-    NMDnsSystemdResolvedPrivate *priv = NM_DNS_SYSTEMD_RESOLVED_GET_PRIVATE(self);
-    GVariantBuilder              dns, domains;
-    NMCListElem *                elem;
-    NMSettingConnectionMdns      mdns     = NM_SETTING_CONNECTION_MDNS_DEFAULT;
-    NMSettingConnectionLlmnr     llmnr    = NM_SETTING_CONNECTION_LLMNR_DEFAULT;
-    const char *                 mdns_arg = NULL, *llmnr_arg = NULL;
-    gboolean                     has_config        = FALSE;
-    gboolean                     has_default_route = FALSE;
+    GVariantBuilder          dns;
+    GVariantBuilder          domains;
+    NMCListElem *            elem;
+    NMSettingConnectionMdns  mdns     = NM_SETTING_CONNECTION_MDNS_DEFAULT;
+    NMSettingConnectionLlmnr llmnr    = NM_SETTING_CONNECTION_LLMNR_DEFAULT;
+    const char *             mdns_arg = NULL, *llmnr_arg = NULL;
+    gboolean                 has_config        = FALSE;
+    gboolean                 has_default_route = FALSE;
 
     g_variant_builder_init(&dns, G_VARIANT_TYPE("(ia(iay))"));
     g_variant_builder_add(&dns, "i", ic->ifindex);
@@ -268,19 +282,20 @@ prepare_one_interface(NMDnsSystemdResolved *self, InterfaceConfig *ic)
     if (!nm_str_is_empty(mdns_arg) || !nm_str_is_empty(llmnr_arg))
         has_config = TRUE;
 
-    _request_item_append(&priv->request_queue_lst_head,
-                         "SetLinkDomains",
-                         g_variant_builder_end(&domains));
-    _request_item_append(&priv->request_queue_lst_head,
-                         "SetLinkDefaultRoute",
+    _request_item_append(self, "SetLinkDomains", ic->ifindex, g_variant_builder_end(&domains));
+    _request_item_append(self,
+                         DBUS_OP_SET_LINK_DEFAULT_ROUTE,
+                         ic->ifindex,
                          g_variant_new("(ib)", ic->ifindex, has_default_route));
-    _request_item_append(&priv->request_queue_lst_head,
+    _request_item_append(self,
                          "SetLinkMulticastDNS",
+                         ic->ifindex,
                          g_variant_new("(is)", ic->ifindex, mdns_arg ?: ""));
-    _request_item_append(&priv->request_queue_lst_head,
+    _request_item_append(self,
                          "SetLinkLLMNR",
+                         ic->ifindex,
                          g_variant_new("(is)", ic->ifindex, llmnr_arg ?: ""));
-    _request_item_append(&priv->request_queue_lst_head, "SetLinkDNS", g_variant_builder_end(&dns));
+    _request_item_append(self, "SetLinkDNS", ic->ifindex, g_variant_builder_end(&dns));
 
     return has_config;
 }