dns: fix handling of searches and domains in resolv.conf

Fix a few issues here:

- nm_utils_merge_ip4_config() didn't reset domains, which would cause domains
    to still be used even if the user elected to ignore DHCP-provided DNS
- nm_ip4_config_add_domain() and nm_ip4_config_add_search() didn't filter
    duplicates
- nm_ip4_config_reset_searches() leaked everything
- If the user had specified an appended search in the connection, that search
    would be added to the 'searches' field in resolv.conf, but any server
    returned domains in 'domain_name' would be ignored because at least one
    search existed.

src/NetworkManagerUtils.c

@@ -204,6 +204,7 @@ nm_utils_merge_ip4_config (NMIP4Config *ip4_config, NMSettingIP4Config *setting)
 
 	if (nm_setting_ip4_config_get_ignore_auto_dns (setting)) {
 		nm_ip4_config_reset_nameservers (ip4_config);
+		nm_ip4_config_reset_domains (ip4_config);
 		nm_ip4_config_reset_searches (ip4_config);
 	}
 

src/named-manager/nm-named-manager.c

@@ -107,16 +107,15 @@ merge_one_ip4_config (NMIP4Config *dst, NMIP4Config *src)
 		nm_ip4_config_add_domain (dst, nm_ip4_config_get_domain (src, i));
 
 	num = nm_ip4_config_get_num_searches (src);
-	if (num > 0) {
 	for (i = 0; i < num; i++)
 		nm_ip4_config_add_search (dst, nm_ip4_config_get_search (src, i));
-	} else {
+
-		/* If no search domains were specified, add the 'domain' list to
+	/* Add the 'domain' list to searches as well since overloading the
-		 * search domains.
+	 * 'domain_name' DHCP field used to be the way you got searches
+	 * into resolv.conf.
 	 */
 	for (i = 0; i < num_domains; i++)
 		nm_ip4_config_add_search (dst, nm_ip4_config_get_domain (src, i));
-	}
 }
 
 
@@ -381,6 +380,35 @@ update_resolv_conf (const char *domain,
 	return *error ? FALSE : TRUE;
 }
 
+static char **
+compute_searches (guint32 num, NMIP4Config *config, gboolean searches)
+{
+	GPtrArray *array;
+	size_t len, elem_len;
+	const char *elem;
+	int i;
+
+	/* Search list is limited to 6 domains total per 'man resolv.conf' */
+	if (num > 6)
+		num = 6;
+
+	array = g_ptr_array_sized_new (num + 1);
+	for (i = 0, len = 0; i < num; i++) {
+		elem = searches ? nm_ip4_config_get_search (config, i)
+			        : nm_ip4_config_get_domain (config, i);
+		elem_len = strlen (elem);
+
+		/* The search list is limited to 256 characters per 'man resolv.conf' */
+		if (len + elem_len > 255)
+			break;
+
+		g_ptr_array_add (array, g_strdup (elem));
+		len += elem_len + 1;  /* +1 for spaces */
+	}
+
+	g_ptr_array_add (array, NULL);
+	return (char **) g_ptr_array_free (array, FALSE);
+}
 
 static gboolean
 rewrite_resolv_conf (NMNamedManager *mgr, const char *iface, GError **error)
@@ -433,21 +461,10 @@ rewrite_resolv_conf (NMNamedManager *mgr, const char *iface, GError **error)
 		domain = nm_ip4_config_get_domain (composite, 0);
 
 	/* Searches */
-	if (num_searches > 0) {
+	if (num_searches > 0)
-		array = g_ptr_array_sized_new (num_searches + 1);
+		searches = compute_searches (num_searches, composite, TRUE);
-		for (i = 0; i < num_searches; i++)
+	else if (num_domains > 0)
-			g_ptr_array_add (array, g_strdup (nm_ip4_config_get_search (composite, i)));
+		searches = compute_searches (num_searches, composite, FALSE);
-
-		g_ptr_array_add (array, NULL);
-		searches = (char **) g_ptr_array_free (array, FALSE);
-	} else if (num_domains > 0) {
-		array = g_ptr_array_sized_new (num_domains + 1);
-		for (i = 0; i < num_domains; i++)
-			g_ptr_array_add (array, g_strdup (nm_ip4_config_get_domain (composite, i)));
-
-		g_ptr_array_add (array, NULL);
-		searches = (char **) g_ptr_array_free (array, FALSE);
-	}
 
 	/* Name servers */
 	num_nameservers = nm_ip4_config_get_num_nameservers (composite);
@@ -473,6 +490,8 @@ rewrite_resolv_conf (NMNamedManager *mgr, const char *iface, GError **error)
 		nameservers = (char **) g_ptr_array_free (array, FALSE);
 	}
 
+	g_object_unref (composite);
+
 #ifdef RESOLVCONF_PATH
 	success = dispatch_resolvconf (domain, searches, nameservers, iface, error);
 #endif

src/nm-ip4-config.c

@@ -352,14 +352,21 @@ void nm_ip4_config_reset_routes (NMIP4Config *config)
 
 void nm_ip4_config_add_domain (NMIP4Config *config, const char *domain)
 {
+	NMIP4ConfigPrivate *priv;
+	int i;
+
 	g_return_if_fail (NM_IS_IP4_CONFIG (config));
 	g_return_if_fail (domain != NULL);
 	g_return_if_fail (strlen (domain) > 0);
 
-	if (!strlen (domain))
+	priv = NM_IP4_CONFIG_GET_PRIVATE (config);
-		return;
 
-	g_ptr_array_add (NM_IP4_CONFIG_GET_PRIVATE (config)->domains, g_strdup (domain));
+	for (i = 0; i < priv->domains->len; i++) {
+		if (!strcmp (g_ptr_array_index (priv->domains, i), domain))
+			return;
+	}
+
+	g_ptr_array_add (priv->domains, g_strdup (domain));
 }
 
 const char *nm_ip4_config_get_domain (NMIP4Config *config, guint i)
@@ -376,13 +383,37 @@ guint32 nm_ip4_config_get_num_domains (NMIP4Config *config)
 	return NM_IP4_CONFIG_GET_PRIVATE (config)->domains->len;
 }
 
+void nm_ip4_config_reset_domains (NMIP4Config *config)
+{
+	NMIP4ConfigPrivate *priv;
+	int i;
+
+	g_return_if_fail (NM_IS_IP4_CONFIG (config));
+
+	priv = NM_IP4_CONFIG_GET_PRIVATE (config);
+	for (i = 0; i < priv->domains->len; i++)
+		g_free (g_ptr_array_index (priv->domains, i));
+	g_ptr_array_free (priv->domains, TRUE);
+	priv->domains = g_ptr_array_sized_new (3);
+}
+
 void nm_ip4_config_add_search (NMIP4Config *config, const char *search)
 {
+	NMIP4ConfigPrivate *priv;
+	int i;
+
 	g_return_if_fail (config != NULL);
 	g_return_if_fail (search != NULL);
 	g_return_if_fail (strlen (search) > 0);
 
-	g_ptr_array_add (NM_IP4_CONFIG_GET_PRIVATE (config)->searches, g_strdup (search));
+	priv = NM_IP4_CONFIG_GET_PRIVATE (config);
+
+	for (i = 0; i < priv->searches->len; i++) {
+		if (!strcmp (g_ptr_array_index (priv->searches, i), search))
+			return;
+	}
+
+	g_ptr_array_add (priv->searches, g_strdup (search));
 }
 
 const char *nm_ip4_config_get_search (NMIP4Config *config, guint i)
@@ -402,12 +433,15 @@ guint32 nm_ip4_config_get_num_searches (NMIP4Config *config)
 void nm_ip4_config_reset_searches (NMIP4Config *config)
 {
 	NMIP4ConfigPrivate *priv;
+	int i;
 
 	g_return_if_fail (NM_IS_IP4_CONFIG (config));
 
 	priv = NM_IP4_CONFIG_GET_PRIVATE (config);
-	if (priv->searches->len)
+	for (i = 0; i < priv->searches->len; i++)
-		g_ptr_array_remove_range (priv->searches, 0, priv->searches->len);
+		g_free (g_ptr_array_index (priv->searches, i));
+	g_ptr_array_free (priv->searches, TRUE);
+	priv->searches = g_ptr_array_sized_new (3);
 }
 
 guint32 nm_ip4_config_get_mtu (NMIP4Config *config)
@@ -696,8 +730,8 @@ nm_ip4_config_init (NMIP4Config *config)
 
 	priv->nameservers = g_array_new (FALSE, TRUE, sizeof (guint32));
 	priv->wins = g_array_new (FALSE, TRUE, sizeof (guint32));
-	priv->domains = g_ptr_array_new ();
+	priv->domains = g_ptr_array_sized_new (3);
-	priv->searches = g_ptr_array_new ();
+	priv->searches = g_ptr_array_sized_new (3);
 }
 
 static void

src/nm-ip4-config.h

@@ -83,6 +83,7 @@ void          nm_ip4_config_reset_routes        (NMIP4Config *config);
 void          nm_ip4_config_add_domain          (NMIP4Config *config, const char *domain);
 const char *  nm_ip4_config_get_domain          (NMIP4Config *config, guint i);
 guint32       nm_ip4_config_get_num_domains     (NMIP4Config *config);
+void          nm_ip4_config_reset_domains       (NMIP4Config *config);
 
 void          nm_ip4_config_add_search          (NMIP4Config *config, const char *search);
 const char *  nm_ip4_config_get_search          (NMIP4Config *config, guint i);