dns: hook plugins into DNS updates and make dnsmasq plugin actually work

4 files changed, 213 insertions, 133 deletions

diff --git a/src/dns-manager/nm-dns-dnsmasq.c b/src/dns-manager/nm-dns-dnsmasq.c
index 5fd6fe6570..a3bf516429 100644
--- a/src/dns-manager/nm-dns-dnsmasq.c
+++ b/src/dns-manager/nm-dns-dnsmasq.c
@@ -41,83 +41,11 @@ G_DEFINE_TYPE (NMDnsDnsmasq, nm_dns_dnsmasq, NM_TYPE_DNS_PLUGIN)
 #define CONFFILE LOCALSTATEDIR "/run/nm-dns-dnsmasq.conf"
 
 typedef struct {
-	int pid;
+	guint32 foo;
 } NMDnsDnsmasqPrivate;
 
 /*******************************************/
 
-#if 0
-static NMCmdLine *
-create_dm_cmd_line (const char *iface,
-                    const char *pidfile,
-                    GError **error)
-{
-	const char *dm_binary;
-	GString *conf;
-	NMIP4Address *tmp;
-	struct in_addr addr;
-	char buf[INET_ADDRSTRLEN + 15];
-	char localaddr[INET_ADDRSTRLEN + 1];
-	int i;
-
-	dm_binary = nm_find_dnsmasq ();
-	if (!dm_binary) {
-		nm_log_warn (LOGD_DNS, "could not find dnsmasq binary.");
-		return NULL;
-	}
-
-	/* Create dnsmasq command line */
-	cmd = nm_cmd_line_new ();
-	nm_cmd_line_add_string (cmd, dm_binary);
-
-	if (getenv ("NM_DNSMASQ_DEBUG"))
-		nm_cmd_line_add_string (cmd, "--log-queries");
-
-	/* dnsmasq may read from it's default config file location, which if that
-	 * location is a valid config file, it will combine with the options here
-	 * and cause undesirable side-effects.  Like sending bogus IP addresses
-	 * as the gateway or whatever.  So give dnsmasq a bogus config file
-	 * location to avoid screwing up the configuration we're passing to it.
-	 */
-	memset (buf, 0, sizeof (buf));
-	strcpy (buf, "/tmp/");
-	for (i = 5; i < 15; i++)
-		buf[i] = (char) (g_random_int_range ((guint32) 'a', (guint32) 'z') & 0xFF);
-	strcat (buf, ".conf");
-
-	nm_cmd_line_add_string (cmd, "--conf-file");
-	nm_cmd_line_add_string (cmd, buf);
-
-	nm_cmd_line_add_string (cmd, "--no-hosts");
-	nm_cmd_line_add_string (cmd, "--keep-in-foreground");
-	nm_cmd_line_add_string (cmd, "--bind-interfaces");
-	nm_cmd_line_add_string (cmd, "--except-interface=lo");
-	nm_cmd_line_add_string (cmd, "--clear-on-reload");
-
-	/* Use strict order since in the case of VPN connections, the VPN's
-	 * nameservers will be first in resolv.conf, and those need to be tried
-	 * first by dnsmasq to successfully resolve names from the VPN.
-	 */
-	nm_cmd_line_add_string (cmd, "--strict-order");
-
-	s = g_string_new ("--listen-address=");
-	addr.s_addr = nm_ip4_address_get_address (tmp);
-	if (!inet_ntop (AF_INET, &addr, &localaddr[0], INET_ADDRSTRLEN)) {
-		nm_log_warn (LOGD_SHARING, "error converting IP4 address 0x%X",
-		             ntohl (addr.s_addr));
-		goto error;
-	}
-	g_string_append (s, localaddr);
-	nm_cmd_line_add_string (cmd, s->str);
-	g_string_free (s, TRUE);
-	return cmd;
-
-error:
-	nm_cmd_line_destroy (cmd);
-	return NULL;
-}
-#endif
-
 static inline const char *
 find_dnsmasq (void)
 {
@@ -234,12 +162,19 @@ update (NMDnsPlugin *plugin,
         const char *hostname)
 {
 	NMDnsDnsmasq *self = NM_DNS_DNSMASQ (plugin);
-	NMDnsDnsmasqPrivate *priv = NM_DNS_DNSMASQ_GET_PRIVATE (self);
 	GString *conf;
 	GSList *iter;
 	const char *argv[10];
 	GError *error = NULL;
 	int ignored;
+	GPid pid = 0;
+
+	/* Kill the old dnsmasq; there doesn't appear to be a way to get dnsmasq
+	 * to reread the config file using SIGHUP or similar.  This is a small race
+	 * here when restarting dnsmasq when DNS requests could go to the upstream
+	 * servers instead of to dnsmasq.
+	 */
+	nm_dns_plugin_child_kill (plugin);
 
 	/* Build up the new dnsmasq config file */
 	conf = g_string_sized_new (150);
@@ -285,17 +220,18 @@ update (NMDnsPlugin *plugin,
 	argv[0] = find_dnsmasq ();
 	argv[1] = "--no-resolv";  /* Use only commandline */
 	argv[2] = "--keep-in-foreground";
-	argv[3] = "--pid-file=" PIDFILE;
-	argv[4] = "--listen-address=127.0.0.1"; /* Should work for both 4 and 6 */
-	argv[5] = "--conf-file=" CONFFILE;
-	argv[6] = NULL;
+	argv[3] = "--bind-interfaces";
+	argv[4] = "--pid-file=" PIDFILE;
+	argv[5] = "--listen-address=127.0.0.1"; /* Should work for both 4 and 6 */
+	argv[6] = "--conf-file=" CONFFILE;
+	argv[7] = NULL;
 
 	/* And finally spawn dnsmasq */
-	priv->pid = nm_dns_plugin_child_spawn (NM_DNS_PLUGIN (self), argv, PIDFILE, "bin/dnsmasq");
+	pid = nm_dns_plugin_child_spawn (NM_DNS_PLUGIN (self), argv, PIDFILE, "bin/dnsmasq");
 
 out:
 	g_string_free (conf, TRUE);
-	return priv->pid ? TRUE : FALSE;
+	return pid ? TRUE : FALSE;
 }
 
 /****************************************************************/
@@ -322,7 +258,6 @@ static void
 child_quit (NMDnsPlugin *plugin, gint status)
 {
 	NMDnsDnsmasq *self = NM_DNS_DNSMASQ (plugin);
-	NMDnsDnsmasqPrivate *priv = NM_DNS_DNSMASQ_GET_PRIVATE (self);
 	gboolean failed = TRUE;
 	int err;
 
@@ -341,12 +276,10 @@ child_quit (NMDnsPlugin *plugin, gint status)
 	} else {
 		nm_log_warn (LOGD_DNS, "dnsmasq died from an unknown cause");
 	}
+	unlink (CONFFILE);
 
 	if (failed)
 		g_signal_emit_by_name (self, NM_DNS_PLUGIN_FAILED);
-
-	priv->pid = 0;
-	unlink (CONFFILE);
 }
 
 /****************************************************************/
@@ -358,11 +291,17 @@ init (NMDnsPlugin *plugin)
 }
 
 static gboolean
-is_exclusive (NMDnsPlugin *plugin)
+is_caching (NMDnsPlugin *plugin)
 {
 	return TRUE;
 }
 
+static const char *
+get_name (NMDnsPlugin *plugin)
+{
+	return "dnsmasq";
+}
+
 /****************************************************************/
 
 NMDnsDnsmasq *
@@ -377,15 +316,27 @@ nm_dns_dnsmasq_init (NMDnsDnsmasq *self)
 }
 
 static void
+dispose (GObject *object)
+{
+	unlink (CONFFILE);
+
+	G_OBJECT_CLASS (nm_dns_dnsmasq_parent_class)->dispose (object);
+}
+
+static void
 nm_dns_dnsmasq_class_init (NMDnsDnsmasqClass *dns_class)
 {
 	NMDnsPluginClass *plugin_class = NM_DNS_PLUGIN_CLASS (dns_class);
+	GObjectClass *object_class = G_OBJECT_CLASS (dns_class);
 
 	g_type_class_add_private (dns_class, sizeof (NMDnsDnsmasqPrivate));
 
+	object_class->dispose = dispose;
+
 	plugin_class->init = init;
 	plugin_class->child_quit = child_quit;
-	plugin_class->is_exclusive = is_exclusive;
+	plugin_class->is_caching = is_caching;
 	plugin_class->update = update;
+	plugin_class->get_name = get_name;
 }
 
diff --git a/src/dns-manager/nm-dns-manager.c b/src/dns-manager/nm-dns-manager.c
index 615532133c..cd39a651e6 100644
--- a/src/dns-manager/nm-dns-manager.c
+++ b/src/dns-manager/nm-dns-manager.c
@@ -245,10 +245,11 @@ dispatch_netconfig (const char *domain,
                     char **nameservers,
                     const char *nis_domain,
                     char **nis_servers,
+                    gboolean caching,
                     const char *iface,
                     GError **error)
 {
-	char *str;
+	char *str, *tmp;
 	GPid pid;
 	gint fd;
 	int ret;
@@ -284,9 +285,14 @@ dispatch_netconfig (const char *domain,
 	}
 
 	if (nameservers) {
-		str = g_strjoinv (" ", nameservers);
+		tmp = g_strjoinv (" ", nameservers);
+		if (caching)
+			str = g_strdup_printf ("127.0.0.1 %s", tmp);
+		else
+			str = g_strdup (tmp);
 		write_to_netconfig (fd, "DNSSERVERS", str);
 		g_free (str);
+		g_free (tmp);
 	}
 
 	if (nis_domain)
@@ -321,6 +327,7 @@ static gboolean
 write_resolv_conf (FILE *f, const char *domain,
                    char **searches,
                    char **nameservers,
+                   gboolean caching,
                    GError **error)
 {
 	char *domain_str = NULL;
@@ -328,6 +335,7 @@ write_resolv_conf (FILE *f, const char *domain,
 	char *nameservers_str = NULL;
 	int i;
 	gboolean retval = FALSE;
+	GString *str;
 
 	if (fprintf (f, "%s","# Generated by NetworkManager\n") < 0) {
 		g_set_error (error,
@@ -349,15 +357,16 @@ write_resolv_conf (FILE *f, const char *domain,
 		g_free (tmp_str);
 	}
 
-	if (nameservers) {
-		GString *str;
-		int num;
+	str = g_string_new ("");
+
+	if (caching)
+		g_string_append_printf (str, "nameserver 127.0.0.1\n");
 
-		str = g_string_new ("");
-		num = g_strv_length (nameservers);
+	if (nameservers) {
+		int num = g_strv_length (nameservers);
 
 		for (i = 0; i < num; i++) {
-			if (i == 3) {
+			if (i == 3 && !caching) {
 				g_string_append (str, "# ");
 				g_string_append (str, _("NOTE: the libc resolver may not support more than 3 nameservers."));
 				g_string_append (str, "\n# ");
@@ -369,14 +378,14 @@ write_resolv_conf (FILE *f, const char *domain,
 			g_string_append (str, nameservers[i]);
 			g_string_append_c (str, '\n');
 		}
-
-		nameservers_str = g_string_free (str, FALSE);
 	}
 
+	nameservers_str = g_string_free (str, FALSE);
+
 	if (fprintf (f, "%s%s%s",
 	             domain_str ? domain_str : "",
 	             searches_str ? searches_str : "",
-	             nameservers_str ? nameservers_str : "") != -1)
+	             strlen (nameservers_str) ? nameservers_str : "") != -1)
 		retval = TRUE;
 
 	g_free (domain_str);
@@ -391,6 +400,7 @@ static gboolean
 dispatch_resolvconf (const char *domain,
                      char **searches,
                      char **nameservers,
+                     gboolean caching,
                      const char *iface,
                      GError **error)
 {
@@ -412,7 +422,7 @@ dispatch_resolvconf (const char *domain,
 			             RESOLVCONF_PATH,
 			             g_strerror (errno));
 		else {
-			retval = write_resolv_conf (f, domain, searches, nameservers, error);
+			retval = write_resolv_conf (f, domain, searches, nameservers, caching, error);
 			retval &= (pclose (f) == 0);
 		}
 	} else {
@@ -432,6 +442,7 @@ static gboolean
 update_resolv_conf (const char *domain,
                     char **searches,
                     char **nameservers,
+                    gboolean caching,
                     const char *iface,
                     GError **error)
 {
@@ -479,7 +490,7 @@ update_resolv_conf (const char *domain,
 		strcpy (tmp_resolv_conf_realpath, RESOLV_CONF);
 	}
 
-	write_resolv_conf (f, domain, searches, nameservers, error);
+	write_resolv_conf (f, domain, searches, nameservers, caching, error);
 
 	if (fclose (f) < 0) {
 		if (*error == NULL) {
@@ -515,23 +526,26 @@ out:
 }
 
 static gboolean
-rewrite_resolv_conf (NMDnsManager *mgr, const char *iface, GError **error)
+update_dns (NMDnsManager *self,
+            const char *iface,
+            gboolean no_caching,
+            GError **error)
 {
 	NMDnsManagerPrivate *priv;
 	NMResolvConfData rc;
-	GSList *iter;
+	GSList *iter, *vpn_configs = NULL, *dev_configs = NULL, *other_configs = NULL;
 	const char *domain = NULL;
 	const char *nis_domain = NULL;
 	char **searches = NULL;
 	char **nameservers = NULL;
 	char **nis_servers = NULL;
 	int num, i, len;
-	gboolean success = FALSE;
+	gboolean success = FALSE, caching = FALSE;
 
 	g_return_val_if_fail (error != NULL, FALSE);
 	g_return_val_if_fail (*error == NULL, FALSE);
 
-	priv = NM_DNS_MANAGER_GET_PRIVATE (mgr);
+	priv = NM_DNS_MANAGER_GET_PRIVATE (self);
 
 	if (iface) {
 		g_free (priv->last_iface);
@@ -618,20 +632,74 @@ rewrite_resolv_conf (NMDnsManager *mgr, const char *iface, GError **error)
 
 	nis_domain = rc.nis_domain;
 
+	/* Build up config lists for plugins; we use the raw configs here, not the
+	 * merged information that we write to resolv.conf so that the plugins can
+	 * still use the domain information in each config to provide split DNS if
+	 * they want to.
+	 */
+	if (priv->ip4_vpn_config)
+		vpn_configs = g_slist_append (vpn_configs, priv->ip4_vpn_config);
+	if (priv->ip6_vpn_config)
+		vpn_configs = g_slist_append (vpn_configs, priv->ip6_vpn_config);
+	if (priv->ip4_device_config)
+		dev_configs = g_slist_append (dev_configs, priv->ip4_device_config);
+	if (priv->ip6_device_config)
+		dev_configs = g_slist_append (dev_configs, priv->ip6_device_config);
+
+	for (iter = priv->configs; iter; iter = g_slist_next (iter)) {
+		if (   (iter->data != priv->ip4_vpn_config)
+		    && (iter->data != priv->ip4_device_config)
+		    && (iter->data != priv->ip6_vpn_config)
+		    && (iter->data != priv->ip6_device_config))
+			other_configs = g_slist_append (other_configs, iter->data);
+	}
+
+	/* Let any plugins do their thing first */
+	for (iter = priv->plugins; iter; iter = g_slist_next (iter)) {
+		NMDnsPlugin *plugin = NM_DNS_PLUGIN (iter->data);
+		const char *plugin_name = nm_dns_plugin_get_name (plugin);
+
+		if (nm_dns_plugin_is_caching (plugin)) {
+			if (no_caching) {
+				nm_log_dbg (LOGD_DNS, "DNS: plugin %s ignored (caching disabled)",
+				            plugin_name);
+				continue;
+			}
+			caching = TRUE;
+		}
+
+		nm_log_dbg (LOGD_DNS, "DNS: updating plugin %s", plugin_name);
+		if (!nm_dns_plugin_update (plugin,
+		                           vpn_configs,
+		                           dev_configs,
+		                           other_configs,
+		                           priv->hostname)) {
+			nm_log_warn (LOGD_DNS, "DNS: plugin %s update failed", plugin_name);
+
+			/* If the plugin failed to update, we shouldn't write out a local
+			 * caching DNS configuration to resolv.conf.
+			 */
+			caching = FALSE;
+		}
+	}
+	g_slist_free (vpn_configs);
+	g_slist_free (dev_configs);
+	g_slist_free (other_configs);
+
 #ifdef RESOLVCONF_PATH
-	success = dispatch_resolvconf (domain, searches, nameservers, iface, error);
+	success = dispatch_resolvconf (domain, searches, nameservers, caching, iface, error);
 #endif
 
 #ifdef TARGET_SUSE
 	if (success == FALSE) {
 		success = dispatch_netconfig (domain, searches, nameservers,
 		                              nis_domain, nis_servers,
-		                              iface, error);
+		                              caching, iface, error);
 	}
 #endif
 
 	if (success == FALSE)
-		success = update_resolv_conf (domain, searches, nameservers, iface, error);
+		success = update_resolv_conf (domain, searches, nameservers, caching, iface, error);
 
 	if (success)
 		nm_system_update_dns ();
@@ -646,6 +714,26 @@ rewrite_resolv_conf (NMDnsManager *mgr, const char *iface, GError **error)
 	return success;
 }
 
+static void
+plugin_failed (NMDnsPlugin *plugin, gpointer user_data)
+{
+	NMDnsManager *self = NM_DNS_MANAGER (user_data);
+	NMDnsManagerPrivate *priv = NM_DNS_MANAGER_GET_PRIVATE (self);
+	GError *error = NULL;
+
+	/* Errors with non-caching plugins aren't fatal */
+	if (!nm_dns_plugin_is_caching (plugin))
+		return;
+
+	/* Disable caching until the next DNS update */
+	if (!update_dns (self, priv->last_iface, TRUE, &error)) {
+		nm_log_warn (LOGD_DNS, "could not commit DNS changes: (%d) %s",
+		             error ? error->code : -1,
+		             error && error->message ? error->message : "(unknown)");
+		g_clear_error (&error);
+	}
+}
+
 gboolean
 nm_dns_manager_add_ip4_config (NMDnsManager *mgr,
                                const char *iface,
@@ -676,9 +764,11 @@ nm_dns_manager_add_ip4_config (NMDnsManager *mgr,
 	if (!g_slist_find (priv->configs, config))
 		priv->configs = g_slist_append (priv->configs, g_object_ref (config));
 
-	if (!rewrite_resolv_conf (mgr, iface, &error)) {
-		nm_log_warn (LOGD_DNS, "could not commit DNS changes: '%s'", error ? error->message : "(none)");
-		g_error_free (error);
+	if (!update_dns (mgr, iface, FALSE, &error)) {
+		nm_log_warn (LOGD_DNS, "could not commit DNS changes: (%d) %s",
+		             error ? error->code : -1,
+		             error && error->message ? error->message : "(unknown)");
+		g_clear_error (&error);
 	}
 
 	return TRUE;
@@ -711,10 +801,11 @@ nm_dns_manager_remove_ip4_config (NMDnsManager *mgr,
 
 	g_object_unref (config);
 
-	if (!rewrite_resolv_conf (mgr, iface, &error)) {
-		nm_log_warn (LOGD_DNS, "could not commit DNS changes: '%s'", error ? error->message : "(none)");
-		if (error)
-			g_error_free (error);
+	if (!update_dns (mgr, iface, FALSE, &error)) {
+		nm_log_warn (LOGD_DNS, "could not commit DNS changes: (%d) %s",
+		             error ? error->code : -1,
+		             error && error->message ? error->message : "(unknown)");
+		g_clear_error (&error);
 	}
 
 	return TRUE;
@@ -752,9 +843,11 @@ nm_dns_manager_add_ip6_config (NMDnsManager *mgr,
 	if (!g_slist_find (priv->configs, config))
 		priv->configs = g_slist_append (priv->configs, g_object_ref (config));
 
-	if (!rewrite_resolv_conf (mgr, iface, &error)) {
-		nm_log_warn (LOGD_DNS, "could not commit DNS changes: '%s'", error ? error->message : "(none)");
-		g_error_free (error);
+	if (!update_dns (mgr, iface, FALSE, &error)) {
+		nm_log_warn (LOGD_DNS, "could not commit DNS changes: (%d) %s",
+		             error ? error->code : -1,
+		             error && error->message ? error->message : "(unknown)");
+		g_clear_error (&error);
 	}
 
 	return TRUE;
@@ -787,10 +880,11 @@ nm_dns_manager_remove_ip6_config (NMDnsManager *mgr,
 
 	g_object_unref (config);	
 
-	if (!rewrite_resolv_conf (mgr, iface, &error)) {
-		nm_log_warn (LOGD_DNS, "could not commit DNS changes: '%s'", error ? error->message : "(none)");
-		if (error)
-			g_error_free (error);
+	if (!update_dns (mgr, iface, FALSE, &error)) {
+		nm_log_warn (LOGD_DNS, "could not commit DNS changes: (%d) %s",
+		             error ? error->code : -1,
+		             error && error->message ? error->message : "(unknown)");
+		g_clear_error (&error);
 	}
 
 	return TRUE;
@@ -824,8 +918,10 @@ nm_dns_manager_set_hostname (NMDnsManager *mgr,
 	 * wants one.  But hostname changes are system-wide and *not* tied to a
 	 * specific interface, so netconfig can't really handle this.  Fake it.
 	 */
-	if (!rewrite_resolv_conf (mgr, priv->last_iface, &error)) {
-		nm_log_warn (LOGD_DNS, "could not commit DNS changes: '%s'", error ? error->message : "(none)");
+	if (!update_dns (mgr, priv->last_iface, FALSE, &error)) {
+		nm_log_warn (LOGD_DNS, "could not commit DNS changes: (%d) %s",
+		             error ? error->code : -1,
+		             error && error->message ? error->message : "(unknown)");
 		g_clear_error (&error);
 	}
 }
@@ -848,6 +944,7 @@ load_plugins (NMDnsManager *self, const char **plugins)
 	NMDnsManagerPrivate *priv = NM_DNS_MANAGER_GET_PRIVATE (self);
 	NMDnsPlugin *plugin;
 	const char **iter;
+	gboolean have_caching = FALSE;
 
 	if (plugins && *plugins) {
 		/* Create each configured plugin */
@@ -859,19 +956,39 @@ load_plugins (NMDnsManager *self, const char **plugins)
 			else if (!strcasecmp (*iter, "chromium"))
 				plugin = NM_DNS_PLUGIN (nm_dns_chromium_new ());
 			else {
-				nm_log_warn (LOGD_DNS, "Unknown DNS plugin '%s'", *iter);
+				nm_log_warn (LOGD_DNS, "Unknown DNS plugin '%s'", *iter);\
+				continue;
+			}
+			g_assert (plugin);
+
+			/* Only one caching DNS plugin is allowed */
+			if (nm_dns_plugin_is_caching (plugin)) {
+				if (have_caching) {
+					nm_log_warn (LOGD_DNS,
+					             "Ignoring plugin %s; only one caching DNS "
+					             "plugin is allowed.",
+					             *iter);
+					g_object_unref (plugin);
+					continue;
+				}
+				have_caching = TRUE;
 			}
 
-			if (plugin)
-				priv->plugins = g_slist_append (priv->plugins, plugin);
+			nm_log_info (LOGD_DNS, "DNS: loaded plugin %s", nm_dns_plugin_get_name (plugin));
+			priv->plugins = g_slist_append (priv->plugins, plugin);
+			g_signal_connect (plugin, NM_DNS_PLUGIN_FAILED,
+			                  G_CALLBACK (plugin_failed),
+			                  self);
 		}
 	} else {
 		/* Create default plugins */
 
 		/* Chromium support */
+#if 0
 		plugin = NM_DNS_PLUGIN (nm_dns_chromium_new ());
 		g_assert (plugin);
 		priv->plugins = g_slist_append (priv->plugins, plugin);
+#endif
 	}
 }
 
diff --git a/src/dns-manager/nm-dns-plugin.c b/src/dns-manager/nm-dns-plugin.c
index bfa80bd87f..d47640b1c3 100644
--- a/src/dns-manager/nm-dns-plugin.c
+++ b/src/dns-manager/nm-dns-plugin.c
@@ -66,15 +66,22 @@ nm_dns_plugin_update (NMDnsPlugin *self,
 }
 
 static gboolean
-is_exclusive (NMDnsPlugin *self)
+is_caching (NMDnsPlugin *self)
 {
 	return FALSE;
 }
 
 gboolean
-nm_dns_plugin_is_exclusive (NMDnsPlugin *self)
+nm_dns_plugin_is_caching (NMDnsPlugin *self)
 {
-	return NM_DNS_PLUGIN_GET_CLASS (self)->is_exclusive (self);
+	return NM_DNS_PLUGIN_GET_CLASS (self)->is_caching (self);
+}
+
+const char *
+nm_dns_plugin_get_name (NMDnsPlugin *self)
+{
+	g_assert (NM_DNS_PLUGIN_GET_CLASS (self)->get_name);
+	return NM_DNS_PLUGIN_GET_CLASS (self)->get_name (self);
 }
 
 /********************************************/
@@ -158,9 +165,9 @@ nm_dns_plugin_child_spawn (NMDnsPlugin *self,
 		priv->pidfile = g_strdup (pidfile);
 	}
 
-	nm_log_info (LOGD_DNS, "Starting %s...", priv->progname);
+	nm_log_info (LOGD_DNS, "DNS: starting %s...", priv->progname);
 	cmdline = g_strjoinv (" ", (char **) argv);
-	nm_log_dbg (LOGD_DNS, "Command line: %s", cmdline);
+	nm_log_dbg (LOGD_DNS, "DNS: command line: %s", cmdline);
 	g_free (cmdline);
 
 	priv->pid = 0;
@@ -287,7 +294,7 @@ nm_dns_plugin_class_init (NMDnsPluginClass *plugin_class)
 	/* virtual methods */
 	object_class->dispose = dispose;
 	object_class->finalize = finalize;
-	plugin_class->is_exclusive = is_exclusive;
+	plugin_class->is_caching = is_caching;
 
 	/* signals */
 	signals[FAILED] =
diff --git a/src/dns-manager/nm-dns-plugin.h b/src/dns-manager/nm-dns-plugin.h
index cb8fabe1ff..d4298b869d 100644
--- a/src/dns-manager/nm-dns-plugin.h
+++ b/src/dns-manager/nm-dns-plugin.h
@@ -59,7 +59,10 @@ typedef struct {
 	 * caching nameserver that listens on localhost and would block any
 	 * other local caching nameserver from operating.
 	 */
-	gboolean (*is_exclusive) (NMDnsPlugin *self);
+	gboolean (*is_caching) (NMDnsPlugin *self);
+
+	/* Subclasses should override this and return their plugin name */
+	const char *(*get_name) (NMDnsPlugin *self);
 
 	/* Signals */
 
@@ -80,7 +83,9 @@ typedef struct {
 
 GType nm_dns_plugin_get_type (void);
 
-gboolean nm_dns_plugin_is_exclusive (NMDnsPlugin *self);
+gboolean nm_dns_plugin_is_caching (NMDnsPlugin *self);
+
+const char *nm_dns_plugin_get_name (NMDnsPlugin *self);
 
 gboolean nm_dns_plugin_update (NMDnsPlugin *self,
                                const GSList *vpn_configs,