dns: add function to retrieve the systemd-resolved plugin instance

Now that we have nm_dns_systemd_resolved_resolve_address(), we also
need a way to obtain a reference to the plugin.

(cherry picked from commit 7285bc56a9)

src/core/dns/nm-dns-dnsmasq.h

@@ -7,6 +7,7 @@
 #define __NETWORKMANAGER_DNS_DNSMASQ_H__
 
 #include "nm-dns-plugin.h"
+#include "nm-dns-manager.h"
 
 #define NM_TYPE_DNS_DNSMASQ (nm_dns_dnsmasq_get_type())
 #define NM_DNS_DNSMASQ(obj) (G_TYPE_CHECK_INSTANCE_CAST((obj), NM_TYPE_DNS_DNSMASQ, NMDnsDnsmasq))

src/core/dns/nm-dns-manager.c

@@ -378,11 +378,11 @@ _mgr_get_configs_lst_head(NMDnsManager *self)
 
 /*****************************************************************************/
 
-gboolean
-nm_dns_manager_has_systemd_resolved(NMDnsManager *self)
+NMDnsPlugin *
+nm_dns_manager_get_systemd_resolved(NMDnsManager *self)
 {
-    NMDnsManagerPrivate * priv;
-    NMDnsSystemdResolved *plugin = NULL;
+    NMDnsManagerPrivate *priv;
+    NMDnsPlugin *        plugin = NULL;
 
     g_return_val_if_fail(NM_IS_DNS_MANAGER(self), FALSE);
 
@@ -390,11 +390,14 @@ nm_dns_manager_has_systemd_resolved(NMDnsManager *self)
 
     if (priv->sd_resolve_plugin) {
         nm_assert(!NM_IS_DNS_SYSTEMD_RESOLVED(priv->plugin));
-        plugin = NM_DNS_SYSTEMD_RESOLVED(priv->sd_resolve_plugin);
+        plugin = priv->sd_resolve_plugin;
     } else if (NM_IS_DNS_SYSTEMD_RESOLVED(priv->plugin))
-        plugin = NM_DNS_SYSTEMD_RESOLVED(priv->plugin);
+        plugin = priv->plugin;
 
-    return plugin && nm_dns_systemd_resolved_is_running(plugin);
+    if (plugin && nm_dns_systemd_resolved_is_running(NM_DNS_SYSTEMD_RESOLVED(plugin)))
+        return plugin;
+
+    return NULL;
 }
 
 /*****************************************************************************/

src/core/dns/nm-dns-manager.h

@@ -11,6 +11,7 @@
 #include "nm-ip4-config.h"
 #include "nm-ip6-config.h"
 #include "nm-setting-connection.h"
+#include "nm-dns-plugin.h"
 
 typedef enum {
     NM_DNS_IP_CONFIG_TYPE_REMOVED = -1,
@@ -148,7 +149,7 @@ typedef enum {
 
 void nm_dns_manager_stop(NMDnsManager *self);
 
-gboolean nm_dns_manager_has_systemd_resolved(NMDnsManager *self);
+NMDnsPlugin *nm_dns_manager_get_systemd_resolved(NMDnsManager *self);
 
 /*****************************************************************************/
 

src/core/dns/nm-dns-plugin.h

@@ -6,7 +6,8 @@
 #ifndef __NM_DNS_PLUGIN_H__
 #define __NM_DNS_PLUGIN_H__
 
-#include "nm-dns-manager.h"
+#include "c-list/src/c-list.h"
+
 #include "nm-config-data.h"
 
 #define NM_TYPE_DNS_PLUGIN (nm_dns_plugin_get_type())

src/core/dns/nm-dns-systemd-resolved.h

@@ -8,6 +8,7 @@
 #define __NETWORKMANAGER_DNS_SYSTEMD_RESOLVED_H__
 
 #include "nm-dns-plugin.h"
+#include "nm-dns-manager.h"
 
 #define NM_TYPE_DNS_SYSTEMD_RESOLVED (nm_dns_systemd_resolved_get_type())
 #define NM_DNS_SYSTEMD_RESOLVED(obj) \

src/core/nm-connectivity.c

@@ -904,7 +904,7 @@ nm_connectivity_check_start(NMConnectivity *            self,
          * This is relatively cumbersome to avoid, because we would have to go through
          * NMDnsSystemdResolved trying to asynchronously start the service, to ensure there
          * is only one attempt to start the service. */
-        has_systemd_resolved = nm_dns_manager_has_systemd_resolved(nm_dns_manager_get());
+        has_systemd_resolved = !!nm_dns_manager_get_systemd_resolved(nm_dns_manager_get());
 
         if (has_systemd_resolved) {
             GDBusConnection *dbus_connection;