fix(dns): fail to init DHCP DNS servers

internal/cfg/distribution/tun.go

@@ -7,6 +7,7 @@ import (
 	"github.com/igoogolx/itun2socks/internal/constants"
 	"github.com/igoogolx/itun2socks/internal/dns"
 	"github.com/igoogolx/itun2socks/internal/matcher"
+	"github.com/igoogolx/itun2socks/pkg/log"
 )
 
 type Config struct {
@@ -45,15 +46,33 @@ func NewTun(
 	localDns []string,
 	defaultInterfaceName string,
 	disableCache bool,
+	networkService string,
 ) (Config, error) {
 	if len(boostDns) == 0 || len(remoteDns) == 0 || len(localDns) == 0 {
 		return Config{}, fmt.Errorf("dns can't be empty")
 	}
+	originalDnsServers, err := dns.Hijack(networkService, "empty")
+	if err != nil {
+		return Config{}, err
+	}
+	if len(originalDnsServers) != 0 {
+		log.Infoln(log.FormatLog(log.ExecutorPrefix, "current dns servers %v: %v"), networkService, originalDnsServers)
+		defer func(networkService string) {
+			err := dns.Resume(networkService)
+			if err != nil {
+				log.Warnln(log.FormatLog(log.ExecutorPrefix, "fail to resume dns: %v"), err)
+			} else {
+				log.Infoln(log.FormatLog(log.ExecutorPrefix, "resume dns to: %v"), originalDnsServers)
+			}
+		}(networkService)
+	}
+
 	dns.ResetCache()
 	dnsConfig, err := NewDnsDistribution(boostDns, remoteDns, localDns, defaultInterfaceName, disableCache)
 	if err != nil {
 		return Config{}, err
 	}
+
 	return Config{
 		dnsConfig,
 	}, nil

internal/cfg/tun.go

@@ -40,6 +40,7 @@ func NewTun(defaultInterfaceName string) (*Config, error) {
 		rawConfig.Setting.Dns.Server.Local,
 		defaultInterfaceName,
 		disableDnsCache,
+		rawConfig.Setting.NetworkService,
 	)
 
 	if err != nil {

internal/dns/hijack_darwin.go

@@ -4,7 +4,6 @@ package dns
 
 import (
 	"fmt"
-	"github.com/igoogolx/itun2socks/internal/constants"
 	"net"
 	"os/exec"
 	"strings"
@@ -29,26 +28,26 @@ func getOriginalDnsServers(networkService string) ([]string, error) {
 	return dnsServers, nil
 }
 
-func Hijack(networkService string) error {
+func Hijack(networkService string, dnsServer string) ([]string, error) {
 	var err error
 	originalDnsServers, err = getOriginalDnsServers(networkService)
 	if err != nil {
-		return err
+		return nil, err
 	}
-	cmd := exec.Command("networksetup", "-setdnsservers", networkService, constants.HijackedDns)
+	cmd := exec.Command("networksetup", "-setdnsservers", networkService, dnsServer)
 	_, err = cmd.Output()
 	if err != nil {
-		return fmt.Errorf("failed to hajack DNS servers: %v", err)
+		return nil, fmt.Errorf("failed to hajack DNS servers: %v", err)
 	}
-	return nil
+	return originalDnsServers, nil
 }
 
 func Resume(networkService string) error {
 	var err error
 	defer func() {
 		originalDnsServers = []string{}
 	}()
-	dnsServer := "Empty"
+	dnsServer := "empty"
 	if len(originalDnsServers) != 0 {
 		dnsServer = strings.Join(originalDnsServers, " ")
 	}

internal/dns/hijack_others.go

@@ -2,8 +2,8 @@
 
 package dns
 
-func Hijack(_ string) error {
-	return nil
+func Hijack(_ string, server string) ([]string, error) {
+	return []string{}, nil
 }
 
 func Resume(_ string) error {

internal/executor/tun.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"github.com/Dreamacro/clash/component/iface"
 	"github.com/igoogolx/itun2socks/internal/cfg"
+	"github.com/igoogolx/itun2socks/internal/constants"
 	"github.com/igoogolx/itun2socks/internal/dns"
 	localserver "github.com/igoogolx/itun2socks/internal/local_server"
 	"github.com/igoogolx/itun2socks/internal/tunnel/statistic"
@@ -55,7 +56,7 @@ func (c *TunClient) Start() error {
 	}
 	if c.config.HijackDns.Enabled {
 
-		err := dns.Hijack(c.config.HijackDns.NetworkService)
+		_, err := dns.Hijack(c.config.HijackDns.NetworkService, constants.HijackedDns)
 		if err != nil {
 			return err
 		}