Refactor(engine): parse multicast groups (#518)

engine/engine.go

@@ -3,7 +3,6 @@ package engine
 import (
 	"errors"
 	"net"
-	"net/netip"
 	"os/exec"
 	"sync"
 	"time"
@@ -190,6 +189,11 @@ func netstack(k *Key) (err error) {
 		}
 	}()
 
+	multicastGroups, err := parseMulticastGroups(k.MulticastGroups)
+	if err != nil {
+		return err
+	}
+
 	if _defaultProxy, err = parseProxy(k.Proxy); err != nil {
 		return err
 	}
@@ -199,11 +203,6 @@ func netstack(k *Key) (err error) {
 		return err
 	}
 
-	var multicastGroups []netip.Addr
-	if multicastGroups, err = parseMulticastGroups(k.MulticastGroups); err != nil {
-		return err
-	}
-
 	var opts []option.Option
 	if k.TCPModerateReceiveBuffer {
 		opts = append(opts, option.WithTCPModerateReceiveBuffer(true))

engine/key.go

@@ -13,7 +13,7 @@ type Key struct {
 	TCPModerateReceiveBuffer bool          `yaml:"tcp-moderate-receive-buffer"`
 	TCPSendBufferSize        string        `yaml:"tcp-send-buffer-size"`
 	TCPReceiveBufferSize     string        `yaml:"tcp-receive-buffer-size"`
-	MulticastGroups          string        `yaml:"multicast-groups"`
+	MulticastGroups          []string      `yaml:"multicast-groups"`
 	TUNPreUp                 string        `yaml:"tun-pre-up"`
 	TUNPostUp                string        `yaml:"tun-post-up"`
 	UDPTimeout               time.Duration `yaml:"udp-timeout"`

engine/parse.go

@@ -14,11 +14,6 @@ import (
 	"github.com/xjasonlyu/tun2socks/v2/proxy"
 )
 
-const (
-	defaultDeviceType = "tun"
-	defaultProxyType  = "socks5"
-)
-
 func parseRestAPI(s string) (*url.URL, error) {
 	if !strings.Contains(s, "://") {
 		s = fmt.Sprintf("%s://%s", "http", s)
@@ -48,7 +43,7 @@ func parseRestAPI(s string) (*url.URL, error) {
 
 func parseDevice(s string, mtu uint32) (device.Device, error) {
 	if !strings.Contains(s, "://") {
-		s = fmt.Sprintf("%s://%s", defaultDeviceType, s)
+		s = fmt.Sprintf("%s://%s", tun.Driver, s)
 	}
 
 	u, err := url.Parse(s)
@@ -80,7 +75,7 @@ func parseFD(u *url.URL, mtu uint32) (device.Device, error) {
 
 func parseProxy(s string) (proxy.Proxy, error) {
 	if !strings.Contains(s, "://") {
-		s = fmt.Sprintf("%s://%s", defaultProxyType, s)
+		s = fmt.Sprintf("%s://%s", "socks5" /* default */, s)
 	}
 
 	u, err := url.Parse(s)
@@ -90,8 +85,9 @@ func parseProxy(s string) (proxy.Proxy, error) {
 	return proxy.Parse(u)
 }
 
-func parseMulticastGroups(s string) (multicastGroups []netip.Addr, _ error) {
-	for _, ip := range strings.Split(s, ",") {
+func parseMulticastGroups(v []string) ([]netip.Addr, error) {
+	groups := make([]netip.Addr, 0, len(v))
+	for _, ip := range v {
 		if ip = strings.TrimSpace(ip); ip == "" {
 			continue
 		}
@@ -102,7 +98,7 @@ func parseMulticastGroups(s string) (multicastGroups []netip.Addr, _ error) {
 		if !addr.IsMulticast() {
 			return nil, fmt.Errorf("invalid multicast IP: %s", addr)
 		}
-		multicastGroups = append(multicastGroups, addr)
+		groups = append(groups, addr)
 	}
-	return
+	return groups, nil
 }

main.go

@@ -35,7 +35,7 @@ func init() {
 	flag.StringVar(&key.TCPSendBufferSize, "tcp-sndbuf", "", "Set TCP send buffer size for netstack")
 	flag.StringVar(&key.TCPReceiveBufferSize, "tcp-rcvbuf", "", "Set TCP receive buffer size for netstack")
 	flag.BoolVar(&key.TCPModerateReceiveBuffer, "tcp-auto-tuning", false, "Enable TCP receive buffer auto-tuning")
-	flag.StringVar(&key.MulticastGroups, "multicast-groups", "", "Set multicast groups, separated by commas")
+	flag.StringSliceVar(&key.MulticastGroups, "multicast-groups", nil, "Set multicast groups, separated by commas")
 	flag.StringVar(&key.TUNPreUp, "tun-pre-up", "", "Execute a command before TUN device setup")
 	flag.StringVar(&key.TUNPostUp, "tun-post-up", "", "Execute a command after TUN device setup")
 	flag.BoolVarP(&versionFlag, "version", "v", false, "Show version and then quit")

tunnel/tunnel.go

@@ -100,9 +100,9 @@ func (t *Tunnel) Close() {
 
 func (t *Tunnel) Proxy() proxy.Proxy {
 	t.proxyMu.RLock()
-	d := t.proxy
+	p := t.proxy
 	t.proxyMu.RUnlock()
-	return d
+	return p
 }
 
 func (t *Tunnel) SetProxy(proxy proxy.Proxy) {