fix issue #173

chain.go

@@ -3,6 +3,9 @@ package gost
 import (
 	"errors"
 	"net"
+	"strings"
+
+	"github.com/go-log/log"
 )
 
 var (
@@ -122,13 +125,18 @@ func (c *Chain) getConn() (conn net.Conn, nodes []Node, err error) {
 	if selector == nil {
 		selector = &defaultSelector{}
 	}
+	// select node from node group
 	node, err := selector.Select(groups[0].Nodes(), groups[0].Options...)
 	if err != nil {
 		return
 	}
 	nodes = append(nodes, node)
 
-	cn, err := node.Client.Dial(node.Addr, node.DialOptions...)
+	addr, err := selectIP(&node)
+	if err != nil {
+		return
+	}
+	cn, err := node.Client.Dial(addr, node.DialOptions...)
 	if err != nil {
 		return
 	}
@@ -154,8 +162,13 @@ func (c *Chain) getConn() (conn net.Conn, nodes []Node, err error) {
 		}
 		nodes = append(nodes, node)
 
+		addr, err = selectIP(&node)
+		if err != nil {
+			return
+		}
+
 		var cc net.Conn
-		cc, err = preNode.Client.Connect(cn, node.Addr)
+		cc, err = preNode.Client.Connect(cn, addr)
 		if err != nil {
 			cn.Close()
 			return
@@ -172,3 +185,29 @@ func (c *Chain) getConn() (conn net.Conn, nodes []Node, err error) {
 	conn = cn
 	return
 }
+
+func selectIP(node *Node) (string, error) {
+	addr := node.Addr
+	s := node.IPSelector
+	if s == nil {
+		s = &RandomIPSelector{}
+	}
+	// select IP from IP list
+	ip, err := s.Select(node.IPs)
+	if err != nil {
+		return "", err
+	}
+	if ip != "" {
+		if !strings.Contains(ip, ":") {
+			_, sport, err := net.SplitHostPort(addr)
+			if err != nil {
+				return "", err
+			}
+			ip = ip + ":" + sport
+		}
+		addr = ip
+		node.HandshakeOptions = append(node.HandshakeOptions, AddrHandshakeOption(addr))
+	}
+	log.Log("select IP:", node.Addr, node.IPs, addr)
+	return addr, nil
+}

client.go

@@ -4,7 +4,6 @@ import (
 	"crypto/tls"
 	"net"
 	"net/url"
-	"sync/atomic"
 	"time"
 )
 
@@ -64,7 +63,6 @@ type Transporter interface {
 }
 
 type tcpTransporter struct {
-	count uint64
 }
 
 // TCPTransporter creates a transporter for TCP proxy client.
@@ -78,16 +76,6 @@ func (tr *tcpTransporter) Dial(addr string, options ...DialOption) (net.Conn, er
 		option(opts)
 	}
 
-	if len(opts.IPs) > 0 {
-		count := atomic.AddUint64(&tr.count, 1)
-		_, sport, err := net.SplitHostPort(addr)
-		if err != nil {
-			return nil, err
-		}
-		n := uint64(len(opts.IPs))
-		addr = opts.IPs[int(count%n)] + ":" + sport
-	}
-
 	if opts.Chain == nil {
 		return net.DialTimeout("tcp", addr, opts.Timeout)
 	}
@@ -106,7 +94,7 @@ func (tr *tcpTransporter) Multiplex() bool {
 type DialOptions struct {
 	Timeout time.Duration
 	Chain   *Chain
-	IPs     []string
+	// IPs     []string
 }
 
 // DialOption allows a common way to set dial options.
@@ -126,13 +114,6 @@ func ChainDialOption(chain *Chain) DialOption {
 	}
 }
 
-// IPDialOption specifies an IP list used by Transporter.Dial
-func IPDialOption(ips ...string) DialOption {
-	return func(opts *DialOptions) {
-		opts.IPs = ips
-	}
-}
-
 // HandshakeOptions describes the options for handshake.
 type HandshakeOptions struct {
 	Addr       string

cmd/gost/main.go

@@ -81,6 +81,10 @@ func initChain() (*gost.Chain, error) {
 		if err != nil {
 			return nil, err
 		}
+
+		node.IPs = parseIP(node.Values.Get("ip"))
+		node.IPSelector = &gost.RoundRobinIPSelector{}
+
 		users, err := parseUsers(node.Values.Get("secrets"))
 		if err != nil {
 			return nil, err
@@ -201,7 +205,6 @@ func initChain() (*gost.Chain, error) {
 		timeout, _ := strconv.Atoi(node.Values.Get("timeout"))
 		node.DialOptions = append(node.DialOptions,
 			gost.TimeoutDialOption(time.Duration(timeout)*time.Second),
-			gost.IPDialOption(parseIP(node.Values.Get("ip"))...),
 		)
 
 		interval, _ := strconv.Atoi(node.Values.Get("ping"))
@@ -511,9 +514,11 @@ func parseIP(s string) (ips []string) {
 	if err != nil {
 		ss := strings.Split(s, ",")
 		for _, s := range ss {
-			if ip := net.ParseIP(s); ip != nil {
+			s = strings.TrimSpace(s)
+			if s != "" {
 				ips = append(ips, s)
 			}
+
 		}
 		return
 	}
@@ -524,9 +529,7 @@ func parseIP(s string) (ips []string) {
 		if line == "" || strings.HasPrefix(line, "#") {
 			continue
 		}
-		if ip := net.ParseIP(line); ip != nil {
-			ips = append(ips, line)
-		}
+		ips = append(ips, line)
 	}
 	return
 }

node.go

@@ -8,6 +8,7 @@ import (
 // Node is a proxy node, mainly used to construct a proxy chain.
 type Node struct {
 	Addr             string
+	IPs              []string
 	Protocol         string
 	Transport        string
 	Remote           string // remote address, used by tcp/udp port forwarding
@@ -16,6 +17,7 @@ type Node struct {
 	DialOptions      []DialOption
 	HandshakeOptions []HandshakeOption
 	Client           *Client
+	IPSelector       IPSelector
 }
 
 // ParseNode parses the node info.
@@ -81,7 +83,7 @@ func ParseNode(s string) (node Node, err error) {
 type NodeGroup struct {
 	nodes    []Node
 	Options  []SelectOption
-	Selector Selector
+	Selector NodeSelector
 }
 
 // NewNodeGroup creates a node group

selector.go

@@ -1,6 +1,10 @@
 package gost
 
-import "errors"
+import (
+	"errors"
+	"sync/atomic"
+	"time"
+)
 
 var (
 	// ErrNoneAvailable indicates there is no node available
@@ -10,8 +14,8 @@ var (
 // SelectOption used when making a select call
 type SelectOption func(*SelectOptions)
 
-// Selector as a mechanism to pick nodes and mark their status.
-type Selector interface {
+// NodeSelector as a mechanism to pick nodes and mark their status.
+type NodeSelector interface {
 	Select(nodes []Node, opts ...SelectOption) (Node, error)
 	// Mark(node Node)
 	String() string
@@ -71,3 +75,44 @@ func WithStrategy(s Strategy) SelectOption {
 		o.Strategy = s
 	}
 }
+
+// IPSelector as a mechanism to pick IPs and mark their status.
+type IPSelector interface {
+	Select(ips []string) (string, error)
+	String() string
+}
+
+// RandomIPSelector is an IP Selector that selects an IP with random strategy.
+type RandomIPSelector struct {
+}
+
+// Select selects an IP from ips list.
+func (s *RandomIPSelector) Select(ips []string) (string, error) {
+	if len(ips) == 0 {
+		return "", nil
+	}
+	return ips[time.Now().Nanosecond()%len(ips)], nil
+}
+
+func (s *RandomIPSelector) String() string {
+	return "random"
+}
+
+// RoundRobinIPSelector is an IP Selector that selects an IP with round-robin strategy.
+type RoundRobinIPSelector struct {
+	count uint64
+}
+
+// Select selects an IP from ips list.
+func (s *RoundRobinIPSelector) Select(ips []string) (string, error) {
+	if len(ips) == 0 {
+		return "", nil
+	}
+
+	count := atomic.AddUint64(&s.count, 1)
+	return ips[int(count%uint64(len(ips)))], nil
+}
+
+func (s *RoundRobinIPSelector) String() string {
+	return "round"
+}

tls.go

@@ -6,7 +6,6 @@ import (
 	"errors"
 	"net"
 	"sync"
-	"sync/atomic"
 	"time"
 
 	"github.com/go-log/log"
@@ -53,20 +52,10 @@ func (tr *mtlsTransporter) Dial(addr string, options ...DialOption) (conn net.Co
 		option(opts)
 	}
 
-	if len(opts.IPs) > 0 {
-		count := atomic.AddUint64(&tr.count, 1)
-		_, sport, err := net.SplitHostPort(addr)
-		if err != nil {
-			return nil, err
-		}
-		n := uint64(len(opts.IPs))
-		addr = opts.IPs[int(count%n)] + ":" + sport
-	}
-
 	tr.sessionMutex.Lock()
 	defer tr.sessionMutex.Unlock()
 
-	session, ok := tr.sessions[addr] // TODO: the addr may be changed.
+	session, ok := tr.sessions[addr]
 	if !ok {
 		if opts.Chain == nil {
 			conn, err = net.DialTimeout("tcp", addr, opts.Timeout)

ws.go

@@ -10,7 +10,6 @@ import (
 	"net/http"
 	"net/http/httputil"
 	"sync"
-	"sync/atomic"
 	"time"
 
 	"net/url"
@@ -155,20 +154,10 @@ func (tr *mwsTransporter) Dial(addr string, options ...DialOption) (conn net.Con
 		option(opts)
 	}
 
-	if len(opts.IPs) > 0 {
-		count := atomic.AddUint64(&tr.count, 1)
-		_, sport, err := net.SplitHostPort(addr)
-		if err != nil {
-			return nil, err
-		}
-		n := uint64(len(opts.IPs))
-		addr = opts.IPs[int(count%n)] + ":" + sport
-	}
-
 	tr.sessionMutex.Lock()
 	defer tr.sessionMutex.Unlock()
 
-	session, ok := tr.sessions[addr] // TODO: the addr may be changed.
+	session, ok := tr.sessions[addr]
 	if !ok {
 		if opts.Chain == nil {
 			conn, err = net.DialTimeout("tcp", addr, opts.Timeout)
@@ -288,20 +277,10 @@ func (tr *mwssTransporter) Dial(addr string, options ...DialOption) (conn net.Co
 		option(opts)
 	}
 
-	if len(opts.IPs) > 0 {
-		count := atomic.AddUint64(&tr.count, 1)
-		_, sport, err := net.SplitHostPort(addr)
-		if err != nil {
-			return nil, err
-		}
-		n := uint64(len(opts.IPs))
-		addr = opts.IPs[int(count%n)] + ":" + sport
-	}
-
 	tr.sessionMutex.Lock()
 	defer tr.sessionMutex.Unlock()
 
-	session, ok := tr.sessions[addr] // TODO: the addr may be changed.
+	session, ok := tr.sessions[addr]
 	if !ok {
 		if opts.Chain == nil {
 			conn, err = net.DialTimeout("tcp", addr, opts.Timeout)