v1.0.0

transport/internet/tcp/sockopt_linux.go

@@ -0,0 +1,42 @@
+// +build linux
+// +build !confonly
+
+package tcp
+
+import (
+	"syscall"
+
+	"github.com/xtls/xray-core/v1/common/net"
+	"github.com/xtls/xray-core/v1/transport/internet"
+)
+
+const SO_ORIGINAL_DST = 80
+
+func GetOriginalDestination(conn internet.Connection) (net.Destination, error) {
+	sysrawconn, f := conn.(syscall.Conn)
+	if !f {
+		return net.Destination{}, newError("unable to get syscall.Conn")
+	}
+	rawConn, err := sysrawconn.SyscallConn()
+	if err != nil {
+		return net.Destination{}, newError("failed to get sys fd").Base(err)
+	}
+	var dest net.Destination
+	err = rawConn.Control(func(fd uintptr) {
+		addr, err := syscall.GetsockoptIPv6Mreq(int(fd), syscall.IPPROTO_IP, SO_ORIGINAL_DST)
+		if err != nil {
+			newError("failed to call getsockopt").Base(err).WriteToLog()
+			return
+		}
+		ip := net.IPAddress(addr.Multiaddr[4:8])
+		port := uint16(addr.Multiaddr[2])<<8 + uint16(addr.Multiaddr[3])
+		dest = net.TCPDestination(ip, net.Port(port))
+	})
+	if err != nil {
+		return net.Destination{}, newError("failed to control connection").Base(err)
+	}
+	if !dest.IsValid() {
+		return net.Destination{}, newError("failed to call getsockopt")
+	}
+	return dest, nil
+}