No host route needed for nameservers on the same subnet

3 files changed, 64 insertions, 1 deletions

diff --git a/include/inet.h b/include/inet.h
index 207410ae..389a584c 100644
--- a/include/inet.h
+++ b/include/inet.h
@@ -50,6 +50,7 @@ int connman_inet_set_gateway_address(int index, const char *gateway);
 int connman_inet_clear_gateway_address(int index, const char *gateway);
 int connman_inet_set_gateway_interface(int index);
 int connman_inet_clear_gateway_interface(int index);
+connman_bool_t connman_inet_compare_subnet(int index, const char *host);
 
 #ifdef __cplusplus
 }
diff --git a/src/inet.c b/src/inet.c
index cfb7f92f..094c7880 100644
--- a/src/inet.c
+++ b/src/inet.c
@@ -898,3 +898,50 @@ int connman_inet_clear_gateway_interface(int index)
 
 	return err;
 }
+
+connman_bool_t connman_inet_compare_subnet(int index, const char *host)
+{
+	struct ifreq ifr;
+	struct in_addr _host_addr;
+	in_addr_t host_addr, netmask_addr, if_addr;
+	struct sockaddr_in *netmask, *addr;
+	int sk;
+
+	DBG("host %s", host);
+
+	if (host == NULL)
+		return FALSE;
+
+	if (inet_aton(host, &_host_addr) == 0)
+		return -1;
+	host_addr = _host_addr.s_addr;
+
+	sk = socket(PF_INET, SOCK_DGRAM, 0);
+	if (sk < 0)
+		return FALSE;
+
+	memset(&ifr, 0, sizeof(ifr));
+	ifr.ifr_ifindex = index;
+
+	if (ioctl(sk, SIOCGIFNAME, &ifr) < 0) {
+		close(sk);
+		return FALSE;
+	}
+
+	if (ioctl(sk, SIOCGIFNETMASK, &ifr) < 0) {
+		close(sk);
+		return FALSE;
+	}
+
+	netmask = (struct sockaddr_in *)&ifr.ifr_netmask;
+	netmask_addr = netmask->sin_addr.s_addr;
+
+	if (ioctl(sk, SIOCGIFADDR, &ifr) < 0) {
+		close(sk);
+		return FALSE;
+	}
+	addr = (struct sockaddr_in *)&ifr.ifr_addr;
+	if_addr = addr->sin_addr.s_addr;
+
+	return ((if_addr & netmask_addr) == (host_addr & netmask_addr));
+}
diff --git a/src/service.c b/src/service.c
index 93eaa5a1..057b2da3 100644
--- a/src/service.c
+++ b/src/service.c
@@ -384,10 +384,25 @@ void __connman_service_nameserver_add_routes(struct connman_service *service,
 	if (service->nameservers != NULL) {
 		int i;
 
-		for (i = 0; service->nameservers[i]; i++)
+		/*
+		 * We add nameservers host routes for nameservers that
+		 * are not on our subnet. For those who are, the subnet
+		 * route will be installed by the time the dns proxy code
+		 * tries to reach them. The subnet route is installed
+		 * when setting the interface IP address.
+		 */
+		for (i = 0; service->nameservers[i]; i++) {
+			if (connman_inet_compare_subnet(index,
+							service->nameservers[i]))
+				continue;
+
 			connman_inet_add_host_route(index,
 						service->nameservers[i], gw);
+		}
 	} else if (service->nameserver != NULL) {
+		if (connman_inet_compare_subnet(index, service->nameserver))
+			return;
+
 		connman_inet_add_host_route(index, service->nameserver, gw);
 	}
 }