Optimization: use client session cache for TLS connection (#26)

adapters/outbound/socks5.go

@@ -32,6 +32,7 @@ type Socks5 struct {
 	name           string
 	tls            bool
 	skipCertVerify bool
+	tlsConfig      *tls.Config
 }
 
 type Socks5Option struct {
@@ -54,11 +55,9 @@ func (ss *Socks5) Generator(metadata *C.Metadata) (adapter C.ProxyAdapter, err e
 	c, err := net.DialTimeout("tcp", ss.addr, tcpTimeout)
 
 	if err == nil && ss.tls {
-		tlsConfig := tls.Config{
-			InsecureSkipVerify: ss.skipCertVerify,
-			MaxVersion:         tls.VersionTLS12,
-		}
-		c = tls.Client(c, &tlsConfig)
+		cc := tls.Client(c, ss.tlsConfig)
+		err = cc.Handshake()
+		c = cc
 	}
 
 	if err != nil {
@@ -103,10 +102,22 @@ func (ss *Socks5) shakeHand(metadata *C.Metadata, rw io.ReadWriter) error {
 }
 
 func NewSocks5(option Socks5Option) *Socks5 {
+	var tlsConfig *tls.Config
+	if option.TLS {
+		tlsConfig = &tls.Config{
+			InsecureSkipVerify: option.SkipCertVerify,
+			ClientSessionCache: getClientSessionCache(),
+			MinVersion:         tls.VersionTLS11,
+			MaxVersion:         tls.VersionTLS12,
+			ServerName:         option.Server,
+		}
+	}
+
 	return &Socks5{
 		addr:           fmt.Sprintf("%s:%d", option.Server, option.Port),
 		name:           option.Name,
 		tls:            option.TLS,
 		skipCertVerify: option.SkipCertVerify,
+		tlsConfig:      tlsConfig,
 	}
 }