featuer: device add support unixsocket use fd

main.go

@@ -3,6 +3,7 @@ package main
 import (
 	"flag"
 	"fmt"
+	"github.com/xjasonlyu/tun2socks/v2/sock2fd"
 	"os"
 	"os/signal"
 	"syscall"
@@ -61,6 +62,11 @@ func main() {
 		}
 	}
 
+	fd, err := sock2fd.Sock2Fd(key.Device)
+	if err == nil {
+		key.Device = fmt.Sprintf("fd://%d", fd)
+	}
+
 	engine.Insert(key)
 
 	engine.Start()

sock2fd/unix2fd.go

@@ -0,0 +1,41 @@
+package sock2fd
+
+import (
+	"errors"
+	"net"
+	"strings"
+)
+
+func Sock2Fd(s string) (int, error) {
+
+	strSplit := strings.Split(s, "://")
+
+	if strSplit[0] == "unix" || strSplit[0] == "Unix" || strSplit[0] == "UNIX" {
+		return Unix2Fd(strSplit[1])
+	}
+	return 0, errors.New("unsupported socket")
+}
+
+/*
+for example:
+device: unix:///tmp/unix_socket
+*/
+
+func Unix2Fd(path string) (int, error) {
+	conn, err := net.Dial("unix", path)
+	if err != nil {
+		return 0, err
+	}
+
+	unixConn, ok := conn.(*net.UnixConn)
+	if !ok {
+		return 0, errors.New("unexpected")
+	}
+
+	fd, err := unixConn.File()
+	if err != nil {
+		return 0, errors.New("unexpected")
+	}
+
+	return int(fd.Fd()), nil
+}