add gateway per route for tun server side

cmd/gost/cfg.go

@@ -7,6 +7,7 @@ import (
 	"encoding/json"
 	"errors"
 	"io/ioutil"
+	"net"
 	"net/url"
 	"os"
 	"strings"
@@ -273,3 +274,44 @@ func parseHosts(s string) *gost.Hosts {
 
 	return hosts
 }
+
+func parseIPRoutes(s string) (routes []gost.IPRoute) {
+	if s == "" {
+		return
+	}
+
+	file, err := os.Open(s)
+	if err != nil {
+		ss := strings.Split(s, ",")
+		for _, s := range ss {
+			if _, inet, _ := net.ParseCIDR(strings.TrimSpace(s)); inet != nil {
+				routes = append(routes, gost.IPRoute{Dest: inet})
+			}
+		}
+		return
+	}
+
+	defer file.Close()
+	scanner := bufio.NewScanner(file)
+	for scanner.Scan() {
+		line := strings.Replace(scanner.Text(), "\t", " ", -1)
+		line = strings.TrimSpace(line)
+		if line == "" || strings.HasPrefix(line, "#") {
+			continue
+		}
+
+		var route gost.IPRoute
+		ss := strings.Split(line, " ")
+		if len(ss) > 0 && ss[0] != "" {
+			_, route.Dest, _ = net.ParseCIDR(strings.TrimSpace(ss[0]))
+			if route.Dest == nil {
+				continue
+			}
+		}
+		if len(ss) > 1 && ss[1] != "" {
+			route.Gateway = net.ParseIP(ss[1])
+		}
+		routes = append(routes, route)
+	}
+	return routes
+}

cmd/gost/route.go

@@ -311,6 +311,8 @@ func (r *route) GenRouters() ([]router, error) {
 			ttl = time.Duration(node.GetInt("ttl")) * time.Second
 		}
 
+		tunRoutes := parseIPRoutes(node.Get("route"))
+
 		var ln gost.Listener
 		switch node.Transport {
 		case "tls":
@@ -415,7 +417,7 @@ func (r *route) GenRouters() ([]router, error) {
 				Name:    node.Get("name"),
 				Addr:    node.Get("net"),
 				MTU:     node.GetInt("mtu"),
-				Routes:  strings.Split(node.Get("route"), ","),
+				Routes:  tunRoutes,
 				Gateway: node.Get("gw"),
 			}
 			ln, err = gost.TunListener(cfg)
@@ -525,6 +527,7 @@ func (r *route) GenRouters() ([]router, error) {
 			gost.NodeHandlerOption(node),
 			gost.IPsHandlerOption(ips),
 			gost.TCPModeHandlerOption(node.GetBool("tcp")),
+			gost.IPRoutesHandlerOption(tunRoutes...),
 		)
 
 		rt := router{

handler.go

@@ -41,6 +41,7 @@ type HandlerOptions struct {
 	Host          string
 	IPs           []string
 	TCPMode       bool
+	IPRoutes      []IPRoute
 }
 
 // HandlerOption allows a common way to set handler options.
@@ -203,6 +204,13 @@ func TCPModeHandlerOption(b bool) HandlerOption {
 	}
 }
 
+// IPRoutesHandlerOption sets the IP routes for tun tunnel.
+func IPRoutesHandlerOption(routes ...IPRoute) HandlerOption {
+	return func(opts *HandlerOptions) {
+		opts.IPRoutes = routes
+	}
+}
+
 type autoHandler struct {
 	options *HandlerOptions
 }

tuntap.go

@@ -39,11 +39,16 @@ func ipProtocol(p waterutil.IPProtocol) string {
 	return fmt.Sprintf("unknown(%d)", p)
 }
 
+type IPRoute struct {
+	Dest    *net.IPNet
+	Gateway net.IP
+}
+
 type TunConfig struct {
 	Name    string
 	Addr    string
 	MTU     int
-	Routes  []string
+	Routes  []IPRoute
 	Gateway string
 }
 
@@ -224,6 +229,20 @@ func (h *tunHandler) initTunnelConn(pc net.PacketConn) (net.PacketConn, error) {
 	return pc, nil
 }
 
+func (h *tunHandler) findRouteFor(dst net.IP) net.Addr {
+	for _, route := range h.options.IPRoutes {
+		if route.Dest.Contains(dst) && route.Gateway != nil {
+			if v, ok := h.routes.Load(ipToTunRouteKey(route.Gateway)); ok {
+				return v.(net.Addr)
+			}
+		}
+	}
+	if v, ok := h.routes.Load(ipToTunRouteKey(dst)); ok {
+		return v.(net.Addr)
+	}
+	return nil
+}
+
 func (h *tunHandler) transportTun(tun net.Conn, conn net.PacketConn, raddr net.Addr) error {
 	errc := make(chan error, 1)
 
@@ -279,10 +298,7 @@ func (h *tunHandler) transportTun(tun net.Conn, conn net.PacketConn, raddr net.A
 					return err
 				}
 
-				var addr net.Addr
+				addr := h.findRouteFor(dst)
-				if v, ok := h.routes.Load(ipToTunRouteKey(dst)); ok {
-					addr = v.(net.Addr)
-				}
 				if addr == nil {
 					log.Logf("[tun] no route for %s -> %s", src, dst)
 					return nil
@@ -361,11 +377,11 @@ func (h *tunHandler) transportTun(tun net.Conn, conn net.PacketConn, raddr net.A
 					log.Logf("[tun] new route: %s -> %s", src, addr)
 				}
 
-				if v, ok := h.routes.Load(ipToTunRouteKey(dst)); ok {
+				if addr := h.findRouteFor(dst); addr != nil {
 					if Debug {
-						log.Logf("[tun] find route: %s -> %s", dst, v)
+						log.Logf("[tun] find route: %s -> %s", dst, addr)
 					}
-					_, err := conn.WriteTo(b[:n], v.(net.Addr))
+					_, err := conn.WriteTo(b[:n], addr)
 					return err
 				}
 

tuntap_darwin.go

@@ -37,7 +37,7 @@ func createTun(cfg TunConfig) (conn net.Conn, itf *net.Interface, err error) {
 		return
 	}
 
-	if err = addRoutes(ifce.Name(), cfg.Routes...); err != nil {
+	if err = addTunRoutes(ifce.Name(), cfg.Routes...); err != nil {
 		return
 	}
 
@@ -58,12 +58,12 @@ func createTap(cfg TapConfig) (conn net.Conn, itf *net.Interface, err error) {
 	return
 }
 
-func addRoutes(ifName string, routes ...string) error {
+func addTunRoutes(ifName string, routes ...IPRoute) error {
 	for _, route := range routes {
-		if route == "" {
+		if route.Dest == nil {
 			continue
 		}
-		cmd := fmt.Sprintf("route add -net %s -interface %s", route, ifName)
+		cmd := fmt.Sprintf("route add -net %s -interface %s", route.Dest.String(), ifName)
 		log.Log("[tun]", cmd)
 		args := strings.Split(cmd, " ")
 		if er := exec.Command(args[0], args[1:]...).Run(); er != nil {

tuntap_linux.go

@@ -136,14 +136,14 @@ func createTap(cfg TapConfig) (conn net.Conn, itf *net.Interface, err error) {
 	return
 }
 
-func addTunRoutes(ifName string, routes ...string) error {
+func addTunRoutes(ifName string, routes ...IPRoute) error {
 	for _, route := range routes {
-		if route == "" {
+		if route.Dest == nil {
 			continue
 		}
-		cmd := fmt.Sprintf("ip route add %s dev %s", route, ifName)
+		cmd := fmt.Sprintf("ip route add %s dev %s", route.Dest.String(), ifName)
 		log.Logf("[tun] %s", cmd)
-		if err := netlink.AddRoute(route, "", "", ifName); err != nil {
+		if err := netlink.AddRoute(route.Dest.String(), "", "", ifName); err != nil {
 			return fmt.Errorf("%s: %v", cmd, err)
 		}
 	}

tuntap_unix.go

@@ -96,12 +96,12 @@ func createTap(cfg TapConfig) (conn net.Conn, itf *net.Interface, err error) {
 	return
 }
 
-func addTunRoutes(ifName string, routes ...string) error {
+func addTunRoutes(ifName string, routes ...IPRoute) error {
 	for _, route := range routes {
-		if route == "" {
+		if route.Dest == nil {
 			continue
 		}
-		cmd := fmt.Sprintf("route add -net %s -interface %s", route, ifName)
+		cmd := fmt.Sprintf("route add -net %s -interface %s", route.Dest.String(), ifName)
 		log.Logf("[tun] %s", cmd)
 		args := strings.Split(cmd, " ")
 		if er := exec.Command(args[0], args[1:]...).Run(); er != nil {

tuntap_windows.go

@@ -98,16 +98,16 @@ func createTap(cfg TapConfig) (conn net.Conn, itf *net.Interface, err error) {
 	return
 }
 
-func addTunRoutes(ifName string, gw string, routes ...string) error {
+func addTunRoutes(ifName string, gw string, routes ...IPRoute) error {
 	for _, route := range routes {
-		if route == "" {
+		if route.Dest == nil {
 			continue
 		}
 
-		deleteRoute(ifName, route)
+		deleteRoute(ifName, route.Dest.String())
 
 		cmd := fmt.Sprintf("netsh interface ip add route prefix=%s interface=%s store=active",
-			route, ifName)
+			route.Dest.String(), ifName)
 		if gw != "" {
 			cmd += " nexthop=" + gw
 		}