netconfig: Install connected and gateway routes

The routes are installed as a result of a successful installation
of the IP addresses. The gateway is fetched with netconfig_ipv4_get_gateway
helper function according to the origin of the installed IP address.

The route priority offset can be set in main.conf. The default value
of 300 is used if the offset isn’t set.

src/netconfig.c

@@ -204,6 +204,31 @@ static struct netconfig_ifaddr *netconfig_ipv4_get_ifaddr(
 	return NULL;
 }
 
+static char *netconfig_ipv4_get_gateway(struct netconfig *netconfig,
+								uint8_t proto)
+{
+	const struct l_dhcp_lease *lease;
+	const struct l_settings *settings;
+
+	switch (proto) {
+	case RTPROT_STATIC:
+		settings = netconfig_get_connected_network_settings(netconfig);
+		if (!settings)
+			return NULL;
+
+		return l_settings_get_string(settings, "IPv4", "gateway");
+
+	case RTPROT_DHCP:
+		lease = l_dhcp_client_get_lease(netconfig->dhcp_client);
+		if (!lease)
+			return NULL;
+
+		return l_dhcp_lease_get_gateway(lease);
+	}
+
+	return NULL;
+}
+
 static char **netconfig_ipv4_get_dns(struct netconfig *netconfig, uint8_t proto)
 {
 	const struct l_dhcp_lease *lease;
@@ -339,6 +364,76 @@ static void netconfig_ifaddr_cmd_cb(int error, uint16_t type,
 	netconfig_ifaddr_notify(type, data, len, user_data);
 }
 
+/*
+ * Routing priority offset, configurable in main.conf. The route with lower
+ * priority offset is preferred.
+ */
+static int ROUTE_PRIORITY_OFFSET;
+
+static void netconfig_route_cmd_cb(int error, uint16_t type,
+						const void *data, uint32_t len,
+						void *user_data)
+{
+	if (!error)
+		return;
+
+	l_error("netconfig: Route command failure. Error %d: %s",
+						error, strerror(-error));
+}
+
+static bool netconfig_ipv4_routes_install(struct netconfig *netconfig,
+						struct netconfig_ifaddr *ifaddr)
+{
+	L_AUTO_FREE_VAR(char *, gateway) = NULL;
+	struct in_addr in_addr;
+	char *network;
+	uint8_t proto;
+
+	if (inet_pton(AF_INET, ifaddr->ip, &in_addr) < 1)
+		return false;
+
+	in_addr.s_addr = in_addr.s_addr &
+			htonl(0xFFFFFFFFLU << (32 - ifaddr->prefix_len));
+
+	network = inet_ntoa(in_addr);
+	if (!network)
+		return false;
+
+	proto = netconfig->ipv4_is_static ? RTPROT_STATIC : RTPROT_DHCP;
+
+	if (!rtnl_route_ipv4_add_connected(rtnl, netconfig->ifindex,
+						ifaddr->prefix_len, network,
+						ifaddr->ip, proto,
+						netconfig_route_cmd_cb,
+						NULL, NULL)) {
+		l_error("netconfig: Failed to add subnet route.");
+
+		return false;
+	}
+
+	gateway = netconfig_ipv4_get_gateway(netconfig, proto);
+	if (!gateway) {
+		l_error("netconfig: Failed to obtain gateway from %s.",
+			netconfig->ipv4_is_static ?
+					"setting file" : "DHCPv4 lease");
+
+		return false;
+	}
+
+	if (!rtnl_route_ipv4_add_gateway(rtnl, netconfig->ifindex, gateway,
+						ifaddr->ip,
+						ROUTE_PRIORITY_OFFSET,
+						proto, netconfig_route_cmd_cb,
+						NULL, NULL)) {
+		l_error("netconfig: Failed to add route for: %s gateway.",
+								gateway);
+
+		return false;
+	}
+
+	return true;
+}
+
 static void netconfig_ipv4_ifaddr_add_cmd_cb(int error, uint16_t type,
 						const void *data, uint32_t len,
 						void *user_data)
@@ -363,7 +458,11 @@ static void netconfig_ipv4_ifaddr_add_cmd_cb(int error, uint16_t type,
 		return;
 	}
 
-	/* TODO Install the routes */
+	if (!netconfig_ipv4_routes_install(netconfig, ifaddr)) {
+		l_error("netconfig: Failed to install IPv4 routes.");
+
+		goto done;
+	}
 
 	dns = netconfig_ipv4_get_dns(netconfig, netconfig->ipv4_is_static ?
 						RTPROT_STATIC : RTPROT_DHCP);
@@ -703,6 +802,11 @@ static int netconfig_init(void)
 		goto error;
 	}
 
+	if (!l_settings_get_int(iwd_get_config(), "General",
+							"route_priority_offset",
+							&ROUTE_PRIORITY_OFFSET))
+		ROUTE_PRIORITY_OFFSET = 300;
+
 	netconfig_list = l_queue_new();
 
 	return 0;