Feature: add UDP TPROXY support on Linux (#562)

proxy/redir/udp_other.go

@@ -0,0 +1,16 @@
+// +build !linux
+
+package redir
+
+import (
+	"errors"
+	"net"
+)
+
+func setsockopt(c *net.UDPConn, addr string) error {
+	return errors.New("UDP redir not supported on current platform")
+}
+
+func getOrigDst(oob []byte, oobn int) (*net.UDPAddr, error) {
+	return nil, errors.New("UDP redir not supported on current platform")
+}