Update README.md

This reverts commit 2f479b788c.

README.en.md

@@ -44,13 +44,13 @@ Help output under MacOS X:
 ```
 $ ./client_darwin_amd64 -h
 NAME:
-   kcptun - kcptun client
+   kcptun - client(with SMUX)
 
 USAGE:
    client_darwin_amd64 [global options] command [command options] [arguments...]
 
 VERSION:
-   20160820
+   20160922
 
 COMMANDS:
      help, h  Shows a list of commands or help for one command
@@ -58,30 +58,32 @@ COMMANDS:
 GLOBAL OPTIONS:
    --localaddr value, -l value   local listen address (default: ":12948")
    --remoteaddr value, -r value  kcp server address (default: "vps:29900")
-   --key value                   pre-shared secret for client and server (default: "it's a secrect") [$KCPTUN_KEY]
+   --key value                   pre-shared secret between client and server (default: "it's a secrect") [$KCPTUN_KEY]
    --crypt value                 aes, aes-128, aes-192, salsa20, blowfish, twofish, cast5, 3des, tea, xtea, xor, none (default: "aes")
    --mode value                  profiles: fast3, fast2, fast, normal (default: "fast")
    --conn value                  set num of UDP connections to server (default: 1)
-   --mtu value                   set maximum transmission unit of UDP packets (default: 1350)
+   --autoexpire value            set auto expiration time(in seconds) for a single UDP connection, 0 to disable (default: 0)
+   --mtu value                   set maximum transmission unit for UDP packets (default: 1350)
    --sndwnd value                set send window size(num of packets) (default: 128)
    --rcvwnd value                set receive window size(num of packets) (default: 1024)
    --datashard value             set reed-solomon erasure coding - datashard (default: 10)
    --parityshard value           set reed-solomon erasure coding - parityshard (default: 3)
    --dscp value                  set DSCP(6bit) (default: 0)
    --nocomp                      disable compression
+   --log value                   specify a log file to output, default goes to stderr
+   -c value                      config from json file, which will override the command from shell
    --help, -h                    show help
    --version, -v                 print the version
 
-
 $ ./server_darwin_amd64 -h
 NAME:
-   kcptun - kcptun server
+   kcptun - server(with SMUX)
 
 USAGE:
    server_darwin_amd64 [global options] command [command options] [arguments...]
 
 VERSION:
-   20160820
+   20160922
 
 COMMANDS:
      help, h  Shows a list of commands or help for one command
@@ -89,16 +91,18 @@ COMMANDS:
 GLOBAL OPTIONS:
    --listen value, -l value  kcp server listen address (default: ":29900")
    --target value, -t value  target server address (default: "127.0.0.1:12948")
-   --key value               pre-shared secret for client and server (default: "it's a secrect") [$KCPTUN_KEY]
+   --key value               pre-shared secret between client and server (default: "it's a secrect") [$KCPTUN_KEY]
    --crypt value             aes, aes-128, aes-192, salsa20, blowfish, twofish, cast5, 3des, tea, xtea, xor, none (default: "aes")
    --mode value              profiles: fast3, fast2, fast, normal (default: "fast")
-   --mtu value               set maximum transmission unit of UDP packets (default: 1350)
+   --mtu value               set maximum transmission unit for UDP packets (default: 1350)
    --sndwnd value            set send window size(num of packets) (default: 1024)
    --rcvwnd value            set receive window size(num of packets) (default: 1024)
    --datashard value         set reed-solomon erasure coding - datashard (default: 10)
    --parityshard value       set reed-solomon erasure coding - parityshard (default: 3)
    --dscp value              set DSCP(6bit) (default: 0)
    --nocomp                  disable compression
+   --log value               specify a log file to output, default goes to stderr
+   -c value                  config from json file, which will override the command from shell
    --help, -h                show help
    --version, -v             print the version
 ```
@@ -222,7 +226,7 @@ Of which ```RetransSegs,FastRetransSegs,LostSegs,OutSegs``` is the most useful.
 ### *Donations* :dollar:
 ![donate](donate.png)          
 
-All donations to this project will be used on the R&D of [gonet/2](http://gonet2.github.io/).
+Best wishes to you all.
 
 ### *References* :paperclip:
 1. https://github.com/skywind3000/kcp -- KCP - A Fast and Reliable ARQ Protocol.

README.md

@@ -41,13 +41,13 @@
 ```
 $ ./client_darwin_amd64 -h
 NAME:
-   kcptun - kcptun client
+   kcptun - client(with SMUX)
 
 USAGE:
    client_darwin_amd64 [global options] command [command options] [arguments...]
 
 VERSION:
-   20160820
+   20160922
 
 COMMANDS:
      help, h  Shows a list of commands or help for one command
@@ -55,30 +55,32 @@ COMMANDS:
 GLOBAL OPTIONS:
    --localaddr value, -l value   local listen address (default: ":12948")
    --remoteaddr value, -r value  kcp server address (default: "vps:29900")
-   --key value                   pre-shared secret for client and server (default: "it's a secrect") [$KCPTUN_KEY]
+   --key value                   pre-shared secret between client and server (default: "it's a secrect") [$KCPTUN_KEY]
    --crypt value                 aes, aes-128, aes-192, salsa20, blowfish, twofish, cast5, 3des, tea, xtea, xor, none (default: "aes")
    --mode value                  profiles: fast3, fast2, fast, normal (default: "fast")
    --conn value                  set num of UDP connections to server (default: 1)
-   --mtu value                   set maximum transmission unit of UDP packets (default: 1350)
+   --autoexpire value            set auto expiration time(in seconds) for a single UDP connection, 0 to disable (default: 0)
+   --mtu value                   set maximum transmission unit for UDP packets (default: 1350)
    --sndwnd value                set send window size(num of packets) (default: 128)
    --rcvwnd value                set receive window size(num of packets) (default: 1024)
    --datashard value             set reed-solomon erasure coding - datashard (default: 10)
    --parityshard value           set reed-solomon erasure coding - parityshard (default: 3)
    --dscp value                  set DSCP(6bit) (default: 0)
    --nocomp                      disable compression
+   --log value                   specify a log file to output, default goes to stderr
+   -c value                      config from json file, which will override the command from shell
    --help, -h                    show help
    --version, -v                 print the version
 
-
 $ ./server_darwin_amd64 -h
 NAME:
-   kcptun - kcptun server
+   kcptun - server(with SMUX)
 
 USAGE:
    server_darwin_amd64 [global options] command [command options] [arguments...]
 
 VERSION:
-   20160820
+   20160922
 
 COMMANDS:
      help, h  Shows a list of commands or help for one command
@@ -86,16 +88,18 @@ COMMANDS:
 GLOBAL OPTIONS:
    --listen value, -l value  kcp server listen address (default: ":29900")
    --target value, -t value  target server address (default: "127.0.0.1:12948")
-   --key value               pre-shared secret for client and server (default: "it's a secrect") [$KCPTUN_KEY]
+   --key value               pre-shared secret between client and server (default: "it's a secrect") [$KCPTUN_KEY]
    --crypt value             aes, aes-128, aes-192, salsa20, blowfish, twofish, cast5, 3des, tea, xtea, xor, none (default: "aes")
    --mode value              profiles: fast3, fast2, fast, normal (default: "fast")
-   --mtu value               set maximum transmission unit of UDP packets (default: 1350)
+   --mtu value               set maximum transmission unit for UDP packets (default: 1350)
    --sndwnd value            set send window size(num of packets) (default: 1024)
    --rcvwnd value            set receive window size(num of packets) (default: 1024)
    --datashard value         set reed-solomon erasure coding - datashard (default: 10)
    --parityshard value       set reed-solomon erasure coding - parityshard (default: 3)
    --dscp value              set DSCP(6bit) (default: 0)
    --nocomp                  disable compression
+   --log value               specify a log file to output, default goes to stderr
+   -c value                  config from json file, which will override the command from shell
    --help, -h                show help
    --version, -v             print the version
 ```
@@ -175,6 +179,8 @@ DSCP差分服务代码点（Differentiated Services Code Point），IETF于1998
 
 通过 ```-dscp ``` 参数指定dscp值，两端可分别设定。
 
+注意：设置dscp不一定会更好，需要尝试。
+
 ### *前向纠错* :lollipop: 
 前向纠错采用Reed Solomon纠删码, 它的基本原理如下： 给定n个数据块d1, d2,…, dn，n和一个正整数m， RS根据n个数据块生成m个校验块， c1, c2,…, cm。 对于任意的n和m， 从n个原始数据块和m 个校验块中任取n块就能解码出原始数据， 即RS最多容忍m个数据块或者校验块同时丢失。
 
@@ -254,9 +260,9 @@ type Snmp struct {
 ### *捐赠* :dollar:
 ![donate](donate.png)          
 
-对该项目的捐款将用于[gonet/2](http://gonet2.github.io/)游戏服务器框架的研发。     
+好人一生平安
 
-```特别感谢: 郑H立, 南D风, Li, 七q, 凌J，昶，Les*ables, Ky*n, 噼**啦, 等，名字已做特殊处理。```
+```特别感谢: 郑H立, 南D风, Li, 七q, 凌J，昶，Les*ables, Ky*n, 噼**啦, *斌, 小苍**, Ken 等，名字已做特殊处理。```
 
 ### *参考资料* :paperclip:
 1. https://github.com/skywind3000/kcp -- KCP - A Fast and Reliable ARQ Protocol.

client/config.go

@@ -0,0 +1,42 @@
+package main
+
+import (
+	"encoding/json"
+	"os"
+)
+
+// Config for client
+type Config struct {
+	LocalAddr    string `json:"localaddr"`
+	RemoteAddr   string `json:"remoteaddr"`
+	Key          string `json:"key"`
+	Crypt        string `json:"crypt"`
+	Mode         string `json:"mode"`
+	Conn         int    `json:"conn"`
+	AutoExpire   int    `json:"autoexpire"`
+	MTU          int    `json:"mtu"`
+	SndWnd       int    `json:"sndwnd"`
+	RcvWnd       int    `json:"rcvwnd"`
+	DataShard    int    `json:"datashard"`
+	ParityShard  int    `json:"parityshard"`
+	DSCP         int    `json:"dscp"`
+	NoComp       bool   `json:"nocomp"`
+	AckNodelay   bool   `json:"acknodelay"`
+	NoDelay      int    `json:"nodelay"`
+	Interval     int    `json:"interval"`
+	Resend       int    `json:"resend"`
+	NoCongestion int    `json:"nc"`
+	SockBuf      int    `json:"sockbuf"`
+	KeepAlive    int    `json:"keepalive"`
+	Log          string `json:"log"`
+}
+
+func parseJSONConfig(config *Config, path string) error {
+	file, err := os.Open(path) // For read access.
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+
+	return json.NewDecoder(file).Decode(config)
+}

client/main.go

@@ -7,15 +7,15 @@ import (
 	"math/rand"
 	"net"
 	"os"
-	"runtime"
 	"time"
 
 	"golang.org/x/crypto/pbkdf2"
 
 	"github.com/golang/snappy"
+	"github.com/pkg/errors"
 	"github.com/urfave/cli"
 	kcp "github.com/xtaci/kcp-go"
-	"github.com/xtaci/yamux"
+	"github.com/xtaci/smux"
 )
 
 var (
@@ -61,16 +61,10 @@ func handleClient(p1, p2 io.ReadWriteCloser) {
 
 	// start tunnel
 	p1die := make(chan struct{})
-	go func() {
-		io.Copy(p1, p2)
-		close(p1die)
-	}()
+	go func() { io.Copy(p1, p2); close(p1die) }()
 
 	p2die := make(chan struct{})
-	go func() {
-		io.Copy(p2, p1)
-		close(p2die)
-	}()
+	go func() { io.Copy(p2, p1); close(p2die) }()
 
 	// wait for tunnel termination
 	select {
@@ -81,7 +75,7 @@ func handleClient(p1, p2 io.ReadWriteCloser) {
 
 func checkError(err error) {
 	if err != nil {
-		log.Println(err)
+		log.Printf("%+v\n", err)
 		os.Exit(-1)
 	}
 }
@@ -94,7 +88,7 @@ func main() {
 	}
 	myApp := cli.NewApp()
 	myApp.Name = "kcptun"
-	myApp.Usage = "kcptun client"
+	myApp.Usage = "client(with SMUX)"
 	myApp.Version = VERSION
 	myApp.Flags = []cli.Flag{
 		cli.StringFlag{
@@ -158,11 +152,6 @@ func main() {
 			Value: 3,
 			Usage: "set reed-solomon erasure coding - parityshard",
 		},
-		cli.BoolFlag{
-			Name:   "acknodelay",
-			Usage:  "flush ack immediately when a packet is received",
-			Hidden: true,
-		},
 		cli.IntFlag{
 			Name:  "dscp",
 			Value: 0,
@@ -172,6 +161,11 @@ func main() {
 			Name:  "nocomp",
 			Usage: "disable compression",
 		},
+		cli.BoolFlag{
+			Name:   "acknodelay",
+			Usage:  "flush ack immediately when a packet is received",
+			Hidden: true,
+		},
 		cli.IntFlag{
 			Name:   "nodelay",
 			Value:  0,
@@ -202,32 +196,75 @@ func main() {
 			Value:  10, // nat keepalive interval in seconds
 			Hidden: true,
 		},
+		cli.StringFlag{
+			Name:  "log",
+			Value: "",
+			Usage: "specify a log file to output, default goes to stderr",
+		},
+		cli.StringFlag{
+			Name:  "c",
+			Value: "", // when the value is not empty, the config path must exists
+			Usage: "config from json file, which will override the command from shell",
+		},
 	}
 	myApp.Action = func(c *cli.Context) error {
+		config := Config{}
+		config.LocalAddr = c.String("localaddr")
+		config.RemoteAddr = c.String("remoteaddr")
+		config.Key = c.String("key")
+		config.Crypt = c.String("crypt")
+		config.Mode = c.String("mode")
+		config.Conn = c.Int("conn")
+		config.AutoExpire = c.Int("autoexpire")
+		config.MTU = c.Int("mtu")
+		config.SndWnd = c.Int("sndwnd")
+		config.RcvWnd = c.Int("rcvwnd")
+		config.DataShard = c.Int("datashard")
+		config.ParityShard = c.Int("parityshard")
+		config.DSCP = c.Int("dscp")
+		config.NoComp = c.Bool("nocomp")
+		config.AckNodelay = c.Bool("acknodelay")
+		config.NoDelay = c.Int("nodelay")
+		config.Interval = c.Int("interval")
+		config.Resend = c.Int("resend")
+		config.NoCongestion = c.Int("nc")
+		config.SockBuf = c.Int("sockbuf")
+		config.KeepAlive = c.Int("keepalive")
+		config.Log = c.String("log")
+
+		if c.String("c") != "" {
+			err := parseJSONConfig(&config, c.String("c"))
+			checkError(err)
+		}
+
+		// log redirect
+		if config.Log != "" {
+			f, err := os.OpenFile(config.Log, os.O_RDWR|os.O_CREATE|os.O_APPEND, 0666)
+			checkError(err)
+			defer f.Close()
+			log.SetOutput(f)
+		}
+
+		switch config.Mode {
+		case "normal":
+			config.NoDelay, config.Interval, config.Resend, config.NoCongestion = 0, 30, 2, 1
+		case "fast":
+			config.NoDelay, config.Interval, config.Resend, config.NoCongestion = 0, 20, 2, 1
+		case "fast2":
+			config.NoDelay, config.Interval, config.Resend, config.NoCongestion = 1, 20, 2, 1
+		case "fast3":
+			config.NoDelay, config.Interval, config.Resend, config.NoCongestion = 1, 10, 2, 1
+		}
+
 		log.Println("version:", VERSION)
-		addr, err := net.ResolveTCPAddr("tcp", c.String("localaddr"))
+		addr, err := net.ResolveTCPAddr("tcp", config.LocalAddr)
 		checkError(err)
 		listener, err := net.ListenTCP("tcp", addr)
 		checkError(err)
 
-		// kcp server
-		nodelay, interval, resend, nc := c.Int("nodelay"), c.Int("interval"), c.Int("resend"), c.Int("nc")
-
-		switch c.String("mode") {
-		case "normal":
-			nodelay, interval, resend, nc = 0, 30, 2, 1
-		case "fast":
-			nodelay, interval, resend, nc = 0, 20, 2, 1
-		case "fast2":
-			nodelay, interval, resend, nc = 1, 20, 2, 1
-		case "fast3":
-			nodelay, interval, resend, nc = 1, 10, 2, 1
-		}
-
-		crypt := c.String("crypt")
-		pass := pbkdf2.Key([]byte(c.String("key")), []byte(SALT), 4096, 32, sha1.New)
+		pass := pbkdf2.Key([]byte(config.Key), []byte(SALT), 4096, 32, sha1.New)
 		var block kcp.BlockCrypt
-		switch c.String("crypt") {
+		switch config.Crypt {
 		case "tea":
 			block, _ = kcp.NewTEABlockCrypt(pass[:16])
 		case "xor":
@@ -251,92 +288,96 @@ func main() {
 		case "salsa20":
 			block, _ = kcp.NewSalsa20BlockCrypt(pass)
 		default:
-			crypt = "aes"
+			config.Crypt = "aes"
 			block, _ = kcp.NewAESBlockCrypt(pass)
 		}
 
-		remoteaddr := c.String("remoteaddr")
-		datashard, parityshard := c.Int("datashard"), c.Int("parityshard")
-		mtu, sndwnd, rcvwnd := c.Int("mtu"), c.Int("sndwnd"), c.Int("rcvwnd")
-		nocomp, acknodelay := c.Bool("nocomp"), c.Bool("acknodelay")
-		dscp, sockbuf, keepalive, conn := c.Int("dscp"), c.Int("sockbuf"), c.Int("keepalive"), c.Int("conn")
-		autoexpire := c.Int("autoexpire")
-
 		log.Println("listening on:", listener.Addr())
-		log.Println("encryption:", crypt)
-		log.Println("nodelay parameters:", nodelay, interval, resend, nc)
-		log.Println("remote address:", remoteaddr)
-		log.Println("sndwnd:", sndwnd, "rcvwnd:", rcvwnd)
-		log.Println("compression:", !nocomp)
-		log.Println("mtu:", mtu)
-		log.Println("datashard:", datashard, "parityshard:", parityshard)
-		log.Println("acknodelay:", acknodelay)
-		log.Println("dscp:", dscp)
-		log.Println("sockbuf:", sockbuf)
-		log.Println("keepalive:", keepalive)
-		log.Println("conn:", conn)
-		log.Println("autoexpire:", autoexpire)
+		log.Println("encryption:", config.Crypt)
+		log.Println("nodelay parameters:", config.NoDelay, config.Interval, config.Resend, config.NoCongestion)
+		log.Println("remote address:", config.RemoteAddr)
+		log.Println("sndwnd:", config.SndWnd, "rcvwnd:", config.RcvWnd)
+		log.Println("compression:", !config.NoComp)
+		log.Println("mtu:", config.MTU)
+		log.Println("datashard:", config.DataShard, "parityshard:", config.ParityShard)
+		log.Println("acknodelay:", config.AckNodelay)
+		log.Println("dscp:", config.DSCP)
+		log.Println("sockbuf:", config.SockBuf)
+		log.Println("keepalive:", config.KeepAlive)
+		log.Println("conn:", config.Conn)
+		log.Println("autoexpire:", config.AutoExpire)
 
-		config := &yamux.Config{
-			AcceptBacklog:          256,
-			EnableKeepAlive:        true,
-			KeepAliveInterval:      30 * time.Second,
-			ConnectionWriteTimeout: 10 * time.Second,
-			MaxStreamWindowSize:    uint32(sockbuf),
-			LogOutput:              os.Stderr,
-		}
-		createConn := func() *yamux.Session {
-			kcpconn, err := kcp.DialWithOptions(remoteaddr, block, datashard, parityshard)
-			checkError(err)
+		smuxConfig := smux.DefaultConfig()
+		smuxConfig.MaxReceiveBuffer = config.SockBuf
+
+		createConn := func() (*smux.Session, error) {
+			kcpconn, err := kcp.DialWithOptions(config.RemoteAddr, block, config.DataShard, config.ParityShard)
+			if err != nil {
+				return nil, errors.Wrap(err, "createConn()")
+			}
 			kcpconn.SetStreamMode(true)
-			kcpconn.SetNoDelay(nodelay, interval, resend, nc)
-			kcpconn.SetWindowSize(sndwnd, rcvwnd)
-			kcpconn.SetMtu(mtu)
-			kcpconn.SetACKNoDelay(acknodelay)
-			kcpconn.SetKeepAlive(keepalive)
+			kcpconn.SetNoDelay(config.NoDelay, config.Interval, config.Resend, config.NoCongestion)
+			kcpconn.SetWindowSize(config.SndWnd, config.RcvWnd)
+			kcpconn.SetMtu(config.MTU)
+			kcpconn.SetACKNoDelay(config.AckNodelay)
+			kcpconn.SetKeepAlive(config.KeepAlive)
 
-			if err := kcpconn.SetDSCP(dscp); err != nil {
+			if err := kcpconn.SetDSCP(config.DSCP); err != nil {
 				log.Println("SetDSCP:", err)
 			}
-			if err := kcpconn.SetReadBuffer(sockbuf); err != nil {
+			if err := kcpconn.SetReadBuffer(config.SockBuf); err != nil {
 				log.Println("SetReadBuffer:", err)
 			}
-			if err := kcpconn.SetWriteBuffer(sockbuf); err != nil {
+			if err := kcpconn.SetWriteBuffer(config.SockBuf); err != nil {
 				log.Println("SetWriteBuffer:", err)
 			}
 
 			// stream multiplex
-			var session *yamux.Session
-			if nocomp {
-				session, err = yamux.Client(kcpconn, config)
+			var session *smux.Session
+			if config.NoComp {
+				session, err = smux.Client(kcpconn, smuxConfig)
 			} else {
-				session, err = yamux.Client(newCompStream(kcpconn), config)
+				session, err = smux.Client(newCompStream(kcpconn), smuxConfig)
 			}
-			checkError(err)
-			runtime.SetFinalizer(session, func(s *yamux.Session) {
-				s.Close()
-			})
-			return session
+			if err != nil {
+				return nil, errors.Wrap(err, "createConn()")
+			}
+			return session, nil
 		}
 
-		numconn := uint16(conn)
+		// wait until a connection is ready
+		waitConn := func() *smux.Session {
+			for {
+				if session, err := createConn(); err == nil {
+					return session
+				} else {
+					time.Sleep(time.Second)
+				}
+			}
+		}
+
+		numconn := uint16(config.Conn)
 		muxes := make([]struct {
-			session *yamux.Session
+			session *smux.Session
 			ttl     time.Time
 		}, numconn)
 
 		for k := range muxes {
-			muxes[k].session = createConn()
-			muxes[k].ttl = time.Now().Add(time.Duration(autoexpire) * time.Second)
+			sess, err := createConn()
+			checkError(err)
+			muxes[k].session = sess
+			muxes[k].ttl = time.Now().Add(time.Duration(config.AutoExpire) * time.Second)
 		}
 
+		chScavenger := make(chan *smux.Session, 128)
+		go scavenger(chScavenger)
 		rr := uint16(0)
 		for {
 			p1, err := listener.AcceptTCP()
-			if err := p1.SetReadBuffer(sockbuf); err != nil {
+			if err := p1.SetReadBuffer(config.SockBuf); err != nil {
 				log.Println("TCP SetReadBuffer:", err)
 			}
-			if err := p1.SetWriteBuffer(sockbuf); err != nil {
+			if err := p1.SetWriteBuffer(config.SockBuf); err != nil {
 				log.Println("TCP SetWriteBuffer:", err)
 			}
 			checkError(err)
@@ -344,17 +385,18 @@ func main() {
 
 		OPEN_P2:
 			// do auto expiration
-			if autoexpire > 0 && time.Now().After(muxes[idx].ttl) {
-				log.Println("autoexpired")
-				muxes[idx].session = createConn()
-				muxes[idx].ttl = time.Now().Add(time.Duration(autoexpire) * time.Second)
+			if config.AutoExpire > 0 && time.Now().After(muxes[idx].ttl) {
+				chScavenger <- muxes[idx].session
+				muxes[idx].session = waitConn()
+				muxes[idx].ttl = time.Now().Add(time.Duration(config.AutoExpire) * time.Second)
 			}
 
 			// do session open
-			p2, err := muxes[idx].session.Open()
-			if err != nil { // yamux failure
-				muxes[idx].session = createConn()
-				muxes[idx].ttl = time.Now().Add(time.Duration(autoexpire) * time.Second)
+			p2, err := muxes[idx].session.OpenStream()
+			if err != nil { // mux failure
+				chScavenger <- muxes[idx].session
+				muxes[idx].session = waitConn()
+				muxes[idx].ttl = time.Now().Add(time.Duration(config.AutoExpire) * time.Second)
 				goto OPEN_P2
 			}
 			go handleClient(p1, p2)
@@ -363,3 +405,36 @@ func main() {
 	}
 	myApp.Run(os.Args)
 }
+
+type scavengeSession struct {
+	session *smux.Session
+	ttl     time.Time
+}
+
+const (
+	maxScavengeTTL = 10 * time.Minute
+)
+
+func scavenger(ch chan *smux.Session) {
+	ticker := time.NewTicker(30 * time.Second)
+	defer ticker.Stop()
+	var sessionList []scavengeSession
+	for {
+		select {
+		case sess := <-ch:
+			sessionList = append(sessionList, scavengeSession{sess, time.Now()})
+		case <-ticker.C:
+			var newList []scavengeSession
+			for k := range sessionList {
+				s := sessionList[k]
+				if s.session.NumStreams() == 0 || s.session.IsClosed() || time.Since(s.ttl) > maxScavengeTTL {
+					log.Println("session scavenged")
+					s.session.Close()
+				} else {
+					newList = append(newList, sessionList[k])
+				}
+			}
+			sessionList = newList
+		}
+	}
+}

server/config.go

@@ -0,0 +1,40 @@
+package main
+
+import (
+	"encoding/json"
+	"os"
+)
+
+// Config for server
+type Config struct {
+	Listen       string `json:"listen"`
+	Target       string `json:"target"`
+	Key          string `json:"key"`
+	Crypt        string `json:"crypt"`
+	Mode         string `json:"mode"`
+	MTU          int    `json:"mtu"`
+	SndWnd       int    `json:"sndwnd"`
+	RcvWnd       int    `json:"rcvwnd"`
+	DataShard    int    `json:"datashard"`
+	ParityShard  int    `json:"parityshard"`
+	DSCP         int    `json:"dscp"`
+	NoComp       bool   `json:"nocomp"`
+	AckNodelay   bool   `json:"acknodelay"`
+	NoDelay      int    `json:"nodelay"`
+	Interval     int    `json:"interval"`
+	Resend       int    `json:"resend"`
+	NoCongestion int    `json:"nc"`
+	SockBuf      int    `json:"sockbuf"`
+	KeepAlive    int    `json:"keepalive"`
+	Log          string `json:"log"`
+}
+
+func parseJSONConfig(config *Config, path string) error {
+	file, err := os.Open(path) // For read access.
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+
+	return json.NewDecoder(file).Decode(config)
+}

server/main.go

@@ -14,7 +14,7 @@ import (
 	"github.com/golang/snappy"
 	"github.com/urfave/cli"
 	kcp "github.com/xtaci/kcp-go"
-	"github.com/xtaci/yamux"
+	"github.com/xtaci/smux"
 )
 
 var (
@@ -53,34 +53,34 @@ func newCompStream(conn net.Conn) *compStream {
 }
 
 // handle multiplex-ed connection
-func handleMux(conn io.ReadWriteCloser, target string, config *yamux.Config) {
+func handleMux(conn io.ReadWriteCloser, config *Config) {
 	// stream multiplex
-	mux, err := yamux.Server(conn, config)
+	smuxConfig := smux.DefaultConfig()
+	smuxConfig.MaxReceiveBuffer = config.SockBuf
+	mux, err := smux.Server(conn, smuxConfig)
 	if err != nil {
 		log.Println(err)
 		return
 	}
 	defer mux.Close()
 	for {
-		p1, err := mux.Accept()
+		p1, err := mux.AcceptStream()
 		if err != nil {
 			log.Println(err)
 			return
 		}
-		sockbuf := int(config.MaxStreamWindowSize)
-		p2, err := net.DialTimeout("tcp", target, 5*time.Second)
+		p2, err := net.DialTimeout("tcp", config.Target, 5*time.Second)
 		if err != nil {
+			p1.Close()
 			log.Println(err)
-			return
+			continue
 		}
-
-		if err := p2.(*net.TCPConn).SetReadBuffer(sockbuf); err != nil {
+		if err := p2.(*net.TCPConn).SetReadBuffer(config.SockBuf); err != nil {
 			log.Println("TCP SetReadBuffer:", err)
 		}
-		if err := p2.(*net.TCPConn).SetWriteBuffer(sockbuf); err != nil {
+		if err := p2.(*net.TCPConn).SetWriteBuffer(config.SockBuf); err != nil {
 			log.Println("TCP SetWriteBuffer:", err)
 		}
-
 		go handleClient(p1, p2)
 	}
 }
@@ -93,16 +93,10 @@ func handleClient(p1, p2 io.ReadWriteCloser) {
 
 	// start tunnel
 	p1die := make(chan struct{})
-	go func() {
-		io.Copy(p1, p2)
-		close(p1die)
-	}()
+	go func() { io.Copy(p1, p2); close(p1die) }()
 
 	p2die := make(chan struct{})
-	go func() {
-		io.Copy(p2, p1)
-		close(p2die)
-	}()
+	go func() { io.Copy(p2, p1); close(p2die) }()
 
 	// wait for tunnel termination
 	select {
@@ -111,6 +105,13 @@ func handleClient(p1, p2 io.ReadWriteCloser) {
 	}
 }
 
+func checkError(err error) {
+	if err != nil {
+		log.Printf("%+v\n", err)
+		os.Exit(-1)
+	}
+}
+
 func main() {
 	rand.Seed(int64(time.Now().Nanosecond()))
 	if VERSION == "SELFBUILD" {
@@ -119,7 +120,7 @@ func main() {
 	}
 	myApp := cli.NewApp()
 	myApp.Name = "kcptun"
-	myApp.Usage = "kcptun server"
+	myApp.Usage = "server(with SMUX)"
 	myApp.Version = VERSION
 	myApp.Flags = []cli.Flag{
 		cli.StringFlag{
@@ -173,11 +174,6 @@ func main() {
 			Value: 3,
 			Usage: "set reed-solomon erasure coding - parityshard",
 		},
-		cli.BoolFlag{
-			Name:   "acknodelay",
-			Usage:  "flush ack immediately when a packet is received",
-			Hidden: true,
-		},
 		cli.IntFlag{
 			Name:  "dscp",
 			Value: 0,
@@ -187,6 +183,11 @@ func main() {
 			Name:  "nocomp",
 			Usage: "disable compression",
 		},
+		cli.BoolFlag{
+			Name:   "acknodelay",
+			Usage:  "flush ack immediately when a packet is received",
+			Hidden: true,
+		},
 		cli.IntFlag{
 			Name:   "nodelay",
 			Value:  0,
@@ -217,25 +218,69 @@ func main() {
 			Value:  10, // nat keepalive interval in seconds
 			Hidden: true,
 		},
+		cli.StringFlag{
+			Name:  "log",
+			Value: "",
+			Usage: "specify a log file to output, default goes to stderr",
+		},
+		cli.StringFlag{
+			Name:  "c",
+			Value: "", // when the value is not empty, the config path must exists
+			Usage: "config from json file, which will override the command from shell",
+		},
 	}
 	myApp.Action = func(c *cli.Context) error {
-		log.Println("version:", VERSION)
-		nodelay, interval, resend, nc := c.Int("nodelay"), c.Int("interval"), c.Int("resend"), c.Int("nc")
-		switch c.String("mode") {
-		case "normal":
-			nodelay, interval, resend, nc = 0, 30, 2, 1
-		case "fast":
-			nodelay, interval, resend, nc = 0, 20, 2, 1
-		case "fast2":
-			nodelay, interval, resend, nc = 1, 20, 2, 1
-		case "fast3":
-			nodelay, interval, resend, nc = 1, 10, 2, 1
+		config := Config{}
+		config.Listen = c.String("listen")
+		config.Target = c.String("target")
+		config.Key = c.String("key")
+		config.Crypt = c.String("crypt")
+		config.Mode = c.String("mode")
+		config.MTU = c.Int("mtu")
+		config.SndWnd = c.Int("sndwnd")
+		config.RcvWnd = c.Int("rcvwnd")
+		config.DataShard = c.Int("datashard")
+		config.ParityShard = c.Int("parityshard")
+		config.DSCP = c.Int("dscp")
+		config.NoComp = c.Bool("nocomp")
+		config.AckNodelay = c.Bool("acknodelay")
+		config.NoDelay = c.Int("nodelay")
+		config.Interval = c.Int("interval")
+		config.Resend = c.Int("resend")
+		config.NoCongestion = c.Int("nc")
+		config.SockBuf = c.Int("sockbuf")
+		config.KeepAlive = c.Int("keepalive")
+		config.Log = c.String("log")
+
+		if c.String("c") != "" {
+			//Now only support json config file
+			err := parseJSONConfig(&config, c.String("c"))
+			checkError(err)
 		}
 
-		crypt := c.String("crypt")
-		pass := pbkdf2.Key([]byte(c.String("key")), []byte(SALT), 4096, 32, sha1.New)
+		// log redirect
+		if config.Log != "" {
+			f, err := os.OpenFile(config.Log, os.O_RDWR|os.O_CREATE|os.O_APPEND, 0666)
+			checkError(err)
+			defer f.Close()
+			log.SetOutput(f)
+		}
+
+		switch config.Mode {
+		case "normal":
+			config.NoDelay, config.Interval, config.Resend, config.NoCongestion = 0, 30, 2, 1
+		case "fast":
+			config.NoDelay, config.Interval, config.Resend, config.NoCongestion = 0, 20, 2, 1
+		case "fast2":
+			config.NoDelay, config.Interval, config.Resend, config.NoCongestion = 1, 20, 2, 1
+		case "fast3":
+			config.NoDelay, config.Interval, config.Resend, config.NoCongestion = 1, 10, 2, 1
+		}
+
+		log.Println("version:", VERSION)
+		pass := pbkdf2.Key([]byte(config.Key), []byte(SALT), 4096, 32, sha1.New)
 		var block kcp.BlockCrypt
-		switch crypt {
+		switch config.Crypt {
 		case "tea":
 			block, _ = kcp.NewTEABlockCrypt(pass[:16])
 		case "xor":
@@ -259,67 +304,51 @@ func main() {
 		case "salsa20":
 			block, _ = kcp.NewSalsa20BlockCrypt(pass)
 		default:
-			crypt = "aes"
+			config.Crypt = "aes"
 			block, _ = kcp.NewAESBlockCrypt(pass)
 		}
 
-		datashard, parityshard := c.Int("datashard"), c.Int("parityshard")
-		lis, err := kcp.ListenWithOptions(c.String("listen"), block, datashard, parityshard)
-		if err != nil {
-			log.Fatal(err)
-		}
+		lis, err := kcp.ListenWithOptions(config.Listen, block, config.DataShard, config.ParityShard)
+		checkError(err)
+		log.Println("listening on:", lis.Addr())
+		log.Println("target:", config.Target)
+		log.Println("encryption:", config.Crypt)
+		log.Println("nodelay parameters:", config.NoDelay, config.Interval, config.Resend, config.NoCongestion)
+		log.Println("sndwnd:", config.SndWnd, "rcvwnd:", config.RcvWnd)
+		log.Println("compression:", !config.NoComp)
+		log.Println("mtu:", config.MTU)
+		log.Println("datashard:", config.DataShard, "parityshard:", config.ParityShard)
+		log.Println("acknodelay:", config.AckNodelay)
+		log.Println("dscp:", config.DSCP)
+		log.Println("sockbuf:", config.SockBuf)
+		log.Println("keepalive:", config.KeepAlive)
 
-		mtu, sndwnd, rcvwnd := c.Int("mtu"), c.Int("sndwnd"), c.Int("rcvwnd")
-		nocomp, acknodelay := c.Bool("nocomp"), c.Bool("acknodelay")
-		dscp, sockbuf, keepalive := c.Int("dscp"), c.Int("sockbuf"), c.Int("keepalive")
-		target := c.String("target")
-
-		log.Println("listening on ", lis.Addr())
-		log.Println("encryption:", crypt)
-		log.Println("nodelay parameters:", nodelay, interval, resend, nc)
-		log.Println("sndwnd:", sndwnd, "rcvwnd:", rcvwnd)
-		log.Println("compression:", !nocomp)
-		log.Println("mtu:", mtu)
-		log.Println("datashard:", datashard, "parityshard:", parityshard)
-		log.Println("acknodelay:", acknodelay)
-		log.Println("dscp:", dscp)
-		log.Println("sockbuf:", sockbuf)
-		log.Println("keepalive:", keepalive)
-
-		if err := lis.SetDSCP(dscp); err != nil {
+		if err := lis.SetDSCP(config.DSCP); err != nil {
 			log.Println("SetDSCP:", err)
 		}
-		if err := lis.SetReadBuffer(sockbuf); err != nil {
+		if err := lis.SetReadBuffer(config.SockBuf); err != nil {
 			log.Println("SetReadBuffer:", err)
 		}
-		if err := lis.SetWriteBuffer(sockbuf); err != nil {
+		if err := lis.SetWriteBuffer(config.SockBuf); err != nil {
 			log.Println("SetWriteBuffer:", err)
 		}
-		config := &yamux.Config{
-			AcceptBacklog:          256,
-			EnableKeepAlive:        true,
-			KeepAliveInterval:      30 * time.Second,
-			ConnectionWriteTimeout: 10 * time.Second,
-			MaxStreamWindowSize:    uint32(sockbuf),
-			LogOutput:              os.Stderr,
-		}
 		for {
 			if conn, err := lis.AcceptKCP(); err == nil {
 				log.Println("remote address:", conn.RemoteAddr())
 				conn.SetStreamMode(true)
-				conn.SetNoDelay(nodelay, interval, resend, nc)
-				conn.SetMtu(mtu)
-				conn.SetWindowSize(sndwnd, rcvwnd)
-				conn.SetACKNoDelay(acknodelay)
-				conn.SetKeepAlive(keepalive)
+				conn.SetNoDelay(config.NoDelay, config.Interval, config.Resend, config.NoCongestion)
+				conn.SetMtu(config.MTU)
+				conn.SetWindowSize(config.SndWnd, config.RcvWnd)
+				conn.SetACKNoDelay(config.AckNodelay)
+				conn.SetKeepAlive(config.KeepAlive)
 
-				if nocomp {
-					go handleMux(conn, target, config)
+				if config.NoComp {
+					go handleMux(conn, &config)
 				} else {
-					go handleMux(newCompStream(conn), target, config)
+					go handleMux(newCompStream(conn), &config)
 				}
 			} else {
-				log.Println(err)
+				log.Printf("%+v", err)
 			}
 		}
 	}