add timeout for handshake but not for target connecting

better algorithm for backend retry

chain.go

@@ -106,7 +106,7 @@ func (c *Chain) Dial(addr string, opts ...ChainOption) (conn net.Conn, err error
 		opt(options)
 	}
 
-	retries := 1
+	retries := 10 //maximum retry
 	if c != nil && c.Retries > 0 {
 		retries = c.Retries
 	}
@@ -119,6 +119,9 @@ func (c *Chain) Dial(addr string, opts ...ChainOption) (conn net.Conn, err error
 		if err == nil {
 			break
 		}
+		if err == ErrNoneAvailable {
+			break
+		}
 	}
 	return
 }
@@ -128,6 +131,7 @@ func (c *Chain) dialWithOptions(addr string, options *ChainOptions) (net.Conn, e
 		options = &ChainOptions{}
 	}
 	route, err := c.selectRouteFor(addr)
+	//log.Log("Connecting", addr, "using", route.Nodes()[0].Addr, "failcount", route.Nodes()[0].failCount)
 	if err != nil {
 		return nil, err
 	}
@@ -138,17 +142,12 @@ func (c *Chain) dialWithOptions(addr string, options *ChainOptions) (net.Conn, e
 		return net.DialTimeout("tcp", addr, options.Timeout)
 	}
 
-	conn, err := route.getConn()
+	conn, err := route.getConn(addr)
 	if err != nil {
 		return nil, err
 	}
 
-	cc, err := route.LastNode().Client.Connect(conn, addr)
-	if err != nil {
-		conn.Close()
-		return nil, err
-	}
-	return cc, nil
+	return conn, nil
 }
 
 func (c *Chain) resolve(addr string, resolver Resolver, hosts *Hosts) string {
@@ -194,7 +193,7 @@ func (c *Chain) Conn(opts ...ChainOption) (conn net.Conn, err error) {
 		if err != nil {
 			continue
 		}
-		conn, err = route.getConn()
+		conn, err = route.getConn("")
 		if err != nil {
 			log.Log(err)
 			continue
@@ -206,7 +205,7 @@ func (c *Chain) Conn(opts ...ChainOption) (conn net.Conn, err error) {
 }
 
 // getConn obtains a connection to the last node of the chain.
-func (c *Chain) getConn() (conn net.Conn, err error) {
+func (c *Chain) getConn(addr string) (conn net.Conn, err error) {
 	if c.IsEmpty() {
 		err = ErrEmptyChain
 		return
@@ -225,7 +224,10 @@ func (c *Chain) getConn() (conn net.Conn, err error) {
 		node.MarkDead()
 		return
 	}
-	node.ResetDead()
+
+	if len(nodes) > 1 {
+		node.ResetDead() // don't reset the last node as we are going to check if it will connect successfully.
+	}
 
 	preNode := node
 	for _, node := range nodes[1:] {
@@ -242,13 +244,27 @@ func (c *Chain) getConn() (conn net.Conn, err error) {
 			node.MarkDead()
 			return
 		}
+		if len(nodes) > 1 {
 			node.ResetDead()
-
+		}
 		cn = cc
 		preNode = node
 	}
 
 	conn = cn
+	if addr != "" {
+		var cc net.Conn
+		cc, err = node.Client.Connect(conn, addr)
+		if err != nil {
+			if _, ok := err.(*net.OpError); ok {
+				node.MarkDead()
+			}
+			conn.Close()
+			return
+		}
+		conn = cc
+	}
+	node.ResetDead()
 	return
 }
 

socks.go

@@ -215,9 +215,13 @@ func (c *socks5Connector) Connect(conn net.Conn, addr string) (net.Conn, error)
 	)
 
 	cc := gosocks5.ClientConn(conn, selector)
+
+	conn.SetDeadline(time.Now().Add(time.Second * 5))
 	if err := cc.Handleshake(); err != nil {
+		conn.SetDeadline(time.Time{})
 		return nil, err
 	}
+	conn.SetDeadline(time.Time{})
 	conn = cc
 
 	host, port, err := net.SplitHostPort(addr)