tethering: Use fallback nameservers if dnsproxy is not in use

If user has disabled dnsproxy with -r option, then fallback to
user specified nameservers instead of using the Google one.

1 files changed, 37 insertions, 10 deletions

diff --git a/src/tethering.c b/src/tethering.c
index bd79804e..7042040c 100644
--- a/src/tethering.c
+++ b/src/tethering.c
@@ -49,12 +49,11 @@
 #endif
 
 #define BRIDGE_NAME "tether"
-#define BRIDGE_DNS "8.8.8.8"
 
 #define DEFAULT_MTU	1500
 
-#define PRIVATE_NETWORK_PRIMARY_DNS BRIDGE_DNS
-#define PRIVATE_NETWORK_SECONDARY_DNS "8.8.4.4"
+static char *private_network_primary_dns = NULL;
+static char *private_network_secondary_dns = NULL;
 
 static volatile int tethering_enabled;
 static GDHCPServer *tethering_dhcp_server = NULL;
@@ -73,8 +72,8 @@ struct connman_private_network {
 	int index;
 	guint iface_watch;
 	struct connman_ippool *pool;
-	const char *primary_dns;
-	const char *secondary_dns;
+	char *primary_dns;
+	char *secondary_dns;
 };
 
 const char *__connman_tethering_get_bridge(void)
@@ -192,6 +191,7 @@ void __connman_tethering_set_enabled(void)
 	const char *end_ip;
 	const char *dns;
 	unsigned char prefixlen;
+	char **ns;
 
 	DBG("enabled %d", tethering_enabled + 1);
 
@@ -228,11 +228,28 @@ void __connman_tethering_set_enabled(void)
 		return;
 	}
 
+	ns = connman_setting_get_string_list("FallbackNameservers");
+	if (ns != NULL) {
+		if (ns[0] != NULL) {
+			g_free(private_network_primary_dns);
+			private_network_primary_dns = g_strdup(ns[0]);
+		}
+		if (ns[1] != NULL) {
+			g_free(private_network_secondary_dns);
+			private_network_secondary_dns = g_strdup(ns[1]);
+		}
+
+		DBG("Fallback ns primary %s secondary %s",
+			private_network_primary_dns,
+			private_network_secondary_dns);
+	}
+
 	dns = gateway;
 	if (__connman_dnsproxy_add_listener(index) < 0) {
 		connman_error("Can't add listener %s to DNS proxy",
 								BRIDGE_NAME);
-		dns = BRIDGE_DNS;
+		dns = private_network_primary_dns;
+		DBG("Serving %s nameserver to clients", dns);
 	}
 
 	tethering_dhcp_server = dhcp_server_start(BRIDGE_NAME,
@@ -278,6 +295,11 @@ void __connman_tethering_set_disabled(void)
 
 	__connman_bridge_remove(BRIDGE_NAME);
 
+	g_free(private_network_primary_dns);
+	private_network_primary_dns = NULL;
+	g_free(private_network_secondary_dns);
+	private_network_secondary_dns = NULL;
+
 	DBG("tethering stopped");
 }
 
@@ -329,9 +351,12 @@ static void setup_tun_interface(unsigned int flags, unsigned change,
 					DBUS_TYPE_STRING, &server_ip);
 	connman_dbus_dict_append_basic(&dict, "PeerIPv4",
 					DBUS_TYPE_STRING, &peer_ip);
-	connman_dbus_dict_append_basic(&dict, "PrimaryDNS",
+	if (pn->primary_dns != NULL)
+		connman_dbus_dict_append_basic(&dict, "PrimaryDNS",
 					DBUS_TYPE_STRING, &pn->primary_dns);
-	connman_dbus_dict_append_basic(&dict, "SecondaryDNS",
+
+	if (pn->secondary_dns != NULL)
+		connman_dbus_dict_append_basic(&dict, "SecondaryDNS",
 					DBUS_TYPE_STRING, &pn->secondary_dns);
 
 	connman_dbus_dict_close(&array, &dict);
@@ -367,6 +392,8 @@ static void remove_private_network(gpointer user_data)
 	g_free(pn->interface);
 	g_free(pn->owner);
 	g_free(pn->path);
+	g_free(pn->primary_dns);
+	g_free(pn->secondary_dns);
 	g_free(pn);
 }
 
@@ -447,8 +474,8 @@ int __connman_private_network_request(DBusMessage *msg, const char *owner)
 		goto error;
 	}
 
-	pn->primary_dns = PRIVATE_NETWORK_PRIMARY_DNS;
-	pn->secondary_dns = PRIVATE_NETWORK_SECONDARY_DNS;
+	pn->primary_dns = g_strdup(private_network_primary_dns);
+	pn->secondary_dns = g_strdup(private_network_secondary_dns);
 
 	pn->iface_watch = connman_rtnl_add_newlink_watch(index,
 						setup_tun_interface, pn);