feat: 设置dot环境变量

config.go

+package main
+
+import (
+	"os"
+)
+
+func SetDnsServerEnv(isDot bool) error {
+	if isDot {
+		err := os.Setenv("DOT_NAMESERVER", "0.0.0.0:5300")
+		if err != nil {
+			return err
+		}
+	} else {
+		err := os.Setenv("DOT_NAMESERVER", "223.5.5.5:53")
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}

const.go

@@ -7,5 +7,5 @@ const (
 	nat3 = "Port Restricted"
 	nat4 = "Symmetric"
 
-	Version = "v4.11.11"
+	Version = "v4.11.15"
 )

go.mod

 module nat-detect
 
-go 1.23.2
+go 1.22.3
 
 require github.com/ccding/go-stun/stun v0.0.0-20200514191101-4dc67bcdb029

nat.go

@@ -2,9 +2,11 @@ package main
 
 import (
 	"encoding/json"
+	"flag"
 	"fmt"
 	"math/rand"
 	"net"
+	"os"
 	"os/exec"
 	"strconv"
 	"strings"
@@ -21,6 +23,9 @@ var (
 
 	servers []string
 	ports   []string
+
+	version bool
+	debug   bool
 )
 
 type NATInfo struct {
@@ -33,6 +38,10 @@ type NATInfo struct {
 }
 
 func init() {
+	flag.BoolVar(&version, "v", false, "print version and exit")
+	flag.BoolVar(&debug, "d", false, "debug")
+	flag.Parse()
+
 	initMapServer()
 	initSlicePorts()
 
@@ -41,20 +50,47 @@ func init() {
 	natTable[nat2] = 2
 	natTable[nat3] = 3
 	natTable[nat4] = 4
+
+	err := SetDnsServerEnv(true)
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
 }
 
 func main() {
 
+	if version {
+		fmt.Println(Version)
+		os.Exit(0)
+	}
 	c := stun.NewClient()
 	c.SetServerAddr("newstun.bkdomain.cn:3478")
 	nat, _, err := c.Discover()
 	if err != nil {
-		fmt.Println("check nat type failed:", err)
+		if debug {
+			fmt.Println("fail to discover nat[5300]:", err)
+		}
+		if strings.Contains(err.Error(), "dial tcp: lookup") && strings.Contains(err.Error(), "connection refused") {
+			err = SetDnsServerEnv(false)
+			if err != nil {
+				fmt.Println(err)
+				return
+			}
+			nat, _, err = c.Discover()
+			if err != nil {
+				fmt.Println("check nat type failed[53]:", err)
 				return
 			}
+		}
+	}
 
 	natType := nat.String()
 	natType = strings.ToLower(natType)
+
+	if debug {
+		fmt.Println("natType:", natType)
+	}
 	if strings.Contains(natType, "full cone") {
 		NATType = nat1
 	} else if strings.Contains(natType, "symmetric") {
@@ -83,6 +119,7 @@ func main() {
 	}
 	data, err := json.Marshal(info)
 	if err != nil {
+		fmt.Println(err)
 		return
 	}