block-waiting for a connection after the client has been started

This reverts commit 2f479b788c.

.github/ISSUE_TEMPLATE

@@ -0,0 +1,13 @@
+Before firing issue, make sure you figured out the following common questions.
+
+PLEASE DO SEARCH FIRST.
+
+1. Check your ```-key xxx``` for at least 3 times, ***MAKE SURE*** both sides share the same secret.
+2. ```-nocomp, -datashard, -parityshard,  -key, -crypt``` ***must be the same*** on both side.
+3. Did you correctly set the ***-target*** on the server side?
+4. ***MAKE SURE*** ```telnet target port``` on your server successful(don't ask me why couldn't).
+5. Does your ***firewall allows UDP*** communications? (including your ISP Cable-Modem)
+6. Are you using the **same version** for both client & server
+7. Are you using the **latest release**?
+8. Which **OS** do you use?
+9. Which end for this issue related to, **client or server**?

Dockerfile

@@ -1,6 +1,8 @@
-FROM golang:latest
+FROM golang:alpine
 MAINTAINER xtaci <daniel820313@gmail.com>
-RUN go get github.com/xtaci/kcptun/client
-RUN go get github.com/xtaci/kcptun/server
+RUN apk update && \
+    apk upgrade && \
+    apk add git
+RUN go get github.com/xtaci/kcptun/client && go get github.com/xtaci/kcptun/server
 EXPOSE 29900/udp
 EXPOSE 12948

README.en.md

@@ -0,0 +1,240 @@
+# <img src="logo.png" alt="kcptun" height="60px" /> 
+[![Release][13]][14] [![Powered][17]][18] [![MIT licensed][11]][12] [![Build Status][3]][4] [![Go Report Card][5]][6] [![Downloads][15]][16] [![Gitter][19]][20] [![Docker][1]][2]
+[1]: https://images.microbadger.com/badges/image/xtaci/kcptun.svg
+[2]: https://microbadger.com/images/xtaci/kcptun
+[3]: https://travis-ci.org/xtaci/kcptun.svg?branch=master
+[4]: https://travis-ci.org/xtaci/kcptun
+[5]: https://goreportcard.com/badge/github.com/xtaci/kcptun
+[6]: https://goreportcard.com/report/github.com/xtaci/kcptun
+[7]: https://img.shields.io/badge/license-MIT-blue.svg
+[8]: https://raw.githubusercontent.com/xtaci/kcptun/master/LICENSE.md
+[9]: https://img.shields.io/github/stars/xtaci/kcptun.svg
+[10]: https://github.com/xtaci/kcptun/stargazers
+[11]: https://img.shields.io/badge/license-MIT-blue.svg
+[12]: LICENSE.md
+[13]: https://img.shields.io/github/release/xtaci/kcptun.svg
+[14]: https://github.com/xtaci/kcptun/releases/latest
+[15]: https://img.shields.io/github/downloads/xtaci/kcptun/total.svg?maxAge=1800
+[16]: https://github.com/xtaci/kcptun/releases
+[17]: https://img.shields.io/badge/KCP-Powered-blue.svg
+[18]: https://github.com/skywind3000/kcp
+[19]: https://badges.gitter.im/xtaci/kcptun.svg
+[20]: https://gitter.im/xtaci/kcptun?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge
+
+A tool for converting tcp stream into kcp+udp stream, :zap: ***[download address](https://github.com/xtaci/kcptun/releases/latest)***:zap:
+
+![kcptun](kcptun.png)
+
+***kcptun is based on [kcp-go](https://github.com/xtaci/kcp-go)***   
+
+### *QuickStart* :lollipop:
+```
+Server Side: ./server_linux_amd64 -t "127.0.0.1:1080" -l ":4000" -mode fast2  // forwarding to local port 1080
+Client Side: ./client_darwin_amd64 -r "SERVERIP:4000" -l ":1080" -mode fast2  // listening on port 1080
+```
+
+### *Performance* :lollipop:
+<img src="fast.png" alt="fast.com" height="256px" />       
+* Speed tested with: https://fast.com
+* WAN Link Speed: 100M ADSL
+* WIFI: 5GHz TL-WDR3320
+
+### *Usage* :lollipop:
+Help output under MacOS X:
+```
+$ ./client_darwin_amd64 -h
+NAME:
+   kcptun - kcptun client
+
+USAGE:
+   client_darwin_amd64 [global options] command [command options] [arguments...]
+
+VERSION:
+   20160820
+
+COMMANDS:
+     help, h  Shows a list of commands or help for one command
+
+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") [$KCPTUN_KEY]
+   --crypt value                 aes, aes-128, aes-192, salsa20, blowfish, twofish, cast5, 3des, tea, xtea, xor, none (default: "aes")
+   --mode value                  profiles: fast3, fast2, fast, normal (default: "fast")
+   --conn value                  set num of UDP connections to server (default: 1)
+   --mtu value                   set maximum transmission unit of UDP packets (default: 1350)
+   --sndwnd value                set send window size(num of packets) (default: 128)
+   --rcvwnd value                set receive window size(num of packets) (default: 1024)
+   --datashard value             set reed-solomon erasure coding - datashard (default: 10)
+   --parityshard value           set reed-solomon erasure coding - parityshard (default: 3)
+   --dscp value                  set DSCP(6bit) (default: 0)
+   --nocomp                      disable compression
+   --help, -h                    show help
+   --version, -v                 print the version
+
+
+$ ./server_darwin_amd64 -h
+NAME:
+   kcptun - kcptun server
+
+USAGE:
+   server_darwin_amd64 [global options] command [command options] [arguments...]
+
+VERSION:
+   20160820
+
+COMMANDS:
+     help, h  Shows a list of commands or help for one command
+
+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]
+   --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)
+   --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
+   --help, -h                show help
+   --version, -v             print the version
+```
+
+### *Applications* :lollipop:   
+1. Real-time gaming.
+2. Cross-ISP data exchange in PRC.
+3. Other lossy network.
+
+### *Parameters* :lollipop: 
+***Both sides must agree on the following parameters:***
+* datashard
+* parityshard
+* nocomp
+* key
+* crypt
+
+other parameters can be set independently.
+
+*How to optimize*：
+> Step 1：Increase client rcvwnd & server sndwnd simultaneously & gradually。       
+> Step 2：Try download something and observer, if the bandwidth usage is close the limit then stop, otherwise goto step 1.     
+
+***NOTICE: if too much retranmission happens, it's quite possible the windows are too large***
+
+### *Security* :lollipop: 
+No matter what encryption you are using for application layer, if you specify ```-crypt none``` to kcptun, 
+the header will be ***PLAINTEXT*** to everyone; I suggest ```-crypt aes-128``` for encryption at least .
+
+NOTICE: ```-crypt xor``` is also insecure, do not use this unless you know what you are doing.
+
+### *Memory Control* :lollipop: 
+Routers, mobile devices are sensitive to memory consumption; by setting GOGC environment(eg: GOGC=20) will lower memory consumption.
+Reference: https://blog.golang.org/go15gc
+
+### *Traffic Control* :lollipop: 
+***Intended audience : for those server's bandwidth is quite limited.***      
+
+Example: To limit outgoing bandwidth to 32mbit/s on server. 
+```
+root@kcptun:~# cat tc.sh
+tc qdisc del dev eth0 root
+tc qdisc add dev eth0 root handle 1: htb
+tc class add dev eth0 parent 1: classid 1:1 htb rate 32mbit
+tc filter add dev eth0 protocol ip parent 1:0 prio 1 handle 10 fw flowid 1:1
+iptables -t mangle -A POSTROUTING -o eth0  -j MARK --set-mark 10
+root@kcptun:~#
+```
+
+### *DSCP* :lollipop: 
+Differentiated services or DiffServ is a computer networking architecture that specifies a simple, scalable and coarse-grained mechanism for classifying and managing network traffic and providing quality of service (QoS) on modern IP networks. DiffServ can, for example, be used to provide low-latency to critical network traffic such as voice or streaming media while providing simple best-effort service to non-critical services such as web traffic or file transfers.
+
+DiffServ uses a 6-bit differentiated services code point (DSCP) in the 8-bit differentiated services field (DS field) in the IP header for packet classification purposes. The DS field and ECN field replace the outdated IPv4 TOS field.[1]
+
+setting each side with ```-dscp value```.
+
+### *Embeded Mode* :lollipop: 
+Latency:     
+*fast3 >* ***[fast2]*** *> fast > normal > default*        
+Payload Ratio:     
+*default > normal > fast >* ***[fast2]*** *> fast3*       
+Parameters in middle is balanced for latency & payload ratio, the faster you get the more wasteful you are.
+Manual control is supported with hidden parameters, you must understand KCP protocol before doing this.
+```
+ -mode manual -nodelay 1 -resend 2 -nc 1 -interval 20
+```
+I suggest fast2 for high-loss network, normal for low-loss network.
+
+### *Forward Error Correction* :lollipop: 
+In coding theory, the Reed–Solomon code belongs to the class of non-binary cyclic error-correcting codes. The Reed–Solomon code is based on univariate polynomials over finite fields.
+
+It is able to detect and correct multiple symbol errors. By adding t check symbols to the data, a Reed–Solomon code can detect any combination of up to t erroneous symbols, or correct up to ⌊t/2⌋ symbols. As an erasure code, it can correct up to t known erasures, or it can detect and correct combinations of errors and erasures. Furthermore, Reed–Solomon codes are suitable as multiple-burst bit-error correcting codes, since a sequence of b + 1 consecutive bit errors can affect at most two symbols of size b. The choice of t is up to the designer of the code, and may be selected within wide limits.
+
+![reed-solomon](rs.png)
+
+Setting parameters of RS-Code with ```-datashard 10 -parityshard 3``` 
+
+### *Snappy Stream Compression* :lollipop: 
+> Snappy is a compression/decompression library. It does not aim for maximum
+> compression, or compatibility with any other compression library; instead,
+> it aims for very high speeds and reasonable compression. For instance,
+> compared to the fastest mode of zlib, Snappy is an order of magnitude faster
+> for most inputs, but the resulting compressed files are anywhere from 20% to
+> 100% bigger.
+
+> Reference: http://google.github.io/snappy/
+
+disable compression by setting ```-nocomp``` on both side.
+
+> Tips: Turning off compression may reduce latency.
+
+### *SNMP* :lollipop:
+```go
+// Snmp defines network statistics indicator
+type Snmp struct {
+	BytesSent        uint64 // payload bytes sent
+	BytesReceived    uint64
+	MaxConn          uint64
+	ActiveOpens      uint64
+	PassiveOpens     uint64
+	CurrEstab        uint64
+	InErrs           uint64
+	InCsumErrors     uint64 // checksum errors
+	InSegs           uint64
+	OutSegs          uint64
+	OutBytes         uint64 // udp bytes sent
+	RetransSegs      uint64
+	FastRetransSegs  uint64
+	EarlyRetransSegs uint64
+	LostSegs         uint64
+	RepeatSegs       uint64
+	FECRecovered     uint64
+	FECErrs          uint64
+	FECSegs          uint64 // fec segments received
+}
+```
+
+Sending a signal by ```kill -SIGUSR1 pid``` will give SNMP information for KCP，useful for fine-grained adjustment.
+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/).
+
+### *References* :paperclip:
+1. https://github.com/skywind3000/kcp -- KCP - A Fast and Reliable ARQ Protocol.
+2. https://github.com/klauspost/reedsolomon -- Reed-Solomon Erasure Coding in Go.
+3. https://en.wikipedia.org/wiki/Differentiated_services -- DSCP.
+4. http://google.github.io/snappy/ -- A fast compressor/decompressor.
+5. https://www.backblaze.com/blog/reed-solomon/ -- Reed-Solomon Explained.
+6. http://www.qualcomm.cn/products/raptorq -- RaptorQ Forward Error Correction Scheme for Object Delivery.
+7. https://en.wikipedia.org/wiki/PBKDF2 -- Key stretching.
+8. http://blog.appcanary.com/2016/encrypt-or-compress.html -- Should you encrypt or compress first?
+9. https://github.com/hashicorp/yamux -- Connection multiplexing library.
+10. https://tools.ietf.org/html/rfc6937 -- Proportional Rate Reduction for TCP.
+11. https://tools.ietf.org/html/rfc5827 -- Early Retransmit for TCP and Stream Control Transmission Protocol (SCTP).
+12. http://http2.github.io/ -- What is HTTP/2?
+13. http://www.lartc.org/ -- Linux Advanced Routing & Traffic Control

README.md

@@ -1,48 +1,199 @@
 # <img src="logo.png" alt="kcptun" height="60px" /> 
-[![GoDoc][1]][2] [![Build Status][3]][4] [![Go Report Card][5]][6] [![Coverage Statusd][7]][8]
-[1]: https://godoc.org/github.com/xtaci/kcptun?status.svg
-[2]: https://godoc.org/github.com/xtaci/kcptun
+[![Release][13]][14] [![Powered][17]][18] [![MIT licensed][11]][12] [![Build Status][3]][4] [![Go Report Card][5]][6] [![Downloads][15]][16] [![Gitter][19]][20] [![Docker][1]][2]
+[1]: https://images.microbadger.com/badges/image/xtaci/kcptun.svg
+[2]: https://microbadger.com/images/xtaci/kcptun
 [3]: https://travis-ci.org/xtaci/kcptun.svg?branch=master
 [4]: https://travis-ci.org/xtaci/kcptun
-[5]: https://goreportcard.com/badge/xtaci/kcptun
-[6]: https://goreportcard.com/report/xtaci/kcptun
-[7]: https://coveralls.io/repos/github/xtaci/kcptun/badge.svg?branch=master
-[8]: https://coveralls.io/github/xtaci/kcptun?branch=master
+[5]: https://goreportcard.com/badge/github.com/xtaci/kcptun
+[6]: https://goreportcard.com/report/github.com/xtaci/kcptun
+[7]: https://img.shields.io/badge/license-MIT-blue.svg
+[8]: https://raw.githubusercontent.com/xtaci/kcptun/master/LICENSE.md
+[11]: https://img.shields.io/badge/license-MIT-blue.svg
+[12]: LICENSE.md
+[13]: https://img.shields.io/github/release/xtaci/kcptun.svg
+[14]: https://github.com/xtaci/kcptun/releases/latest
+[15]: https://img.shields.io/github/downloads/xtaci/kcptun/total.svg?maxAge=1800
+[16]: https://github.com/xtaci/kcptun/releases
+[17]: https://img.shields.io/badge/KCP-Powered-blue.svg
+[18]: https://github.com/skywind3000/kcp
+[19]: https://badges.gitter.im/xtaci/kcptun.svg
+[20]: https://gitter.im/xtaci/kcptun?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge
 
-TCP流转换为KCP+UDP流，:zap:***[下载地址](https://github.com/xtaci/kcptun/releases/latest)***:zap:工作示意图：  
+***[kcp-go](https://github.com/xtaci/kcp-go)协议测试小工具 :zap: [官方下载地址](https://github.com/xtaci/kcptun/releases/latest):zap:***
 
 ![kcptun](kcptun.png)
-
-***kcptun是[kcp](https://github.com/xtaci/kcp-go)协议的一个简单应用，可以用于任意tcp网络程序的传输承载，以提高在丢包环境下的网络流畅度。***   
-_采用极简设计，客户端＋服务器源码总共400行，方便用户自己扩展_ 。        
-
+[English Readme](README.en.md)
 ### *快速设定* :lollipop:
 ```
-服务器: ./server_linux_amd64 -t "127.0.0.1:1080" -l ":554" -mode fast2  // 转发到本地1080端口
-客户端: ./client_darwin_amd64 -r "IP地址:554" -l ":1080" -mode fast2    // 监听本地1080端口
+服务器: ./server_linux_amd64 -t "127.0.0.1:8388" -l ":4000" -mode fast2  // 转发到服务器的本地8388端口
+客户端: ./client_darwin_amd64 -r "服务器IP地址:4000" -l ":8388" -mode fast2    // 监听客户端的本地8388端口
+注: 服务器端需要有服务监听8388端口
 ```
 
-### *使用の方法* :lollipop:
-![client](client.png)
-![server](server.png)
+### *速度对比* :lollipop:
+<img src="fast.png" alt="fast.com" height="256px" />       
+* 测速网站: https://fast.com
+* 接入: 100M ADSL
+* WIFI: 5GHz TL-WDR3320
 
-### *适用范围限定* :lollipop:   
-1. 实时网络游戏的数据传输        
-2. 跨运营商的流量传输               
-3. 其他高丢包通信链路的TCP承载      
+### *使用方法* :lollipop:
+在Mac OS X El Capitan下的帮助输出: 
+```
+$ ./client_darwin_amd64 -h
+NAME:
+   kcptun - kcptun client
 
-### *推荐参数* :lollipop: 
+USAGE:
+   client_darwin_amd64 [global options] command [command options] [arguments...]
+
+VERSION:
+   20160820
+
+COMMANDS:
+     help, h  Shows a list of commands or help for one command
+
+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") [$KCPTUN_KEY]
+   --crypt value                 aes, aes-128, aes-192, salsa20, blowfish, twofish, cast5, 3des, tea, xtea, xor, none (default: "aes")
+   --mode value                  profiles: fast3, fast2, fast, normal (default: "fast")
+   --conn value                  set num of UDP connections to server (default: 1)
+   --mtu value                   set maximum transmission unit of UDP packets (default: 1350)
+   --sndwnd value                set send window size(num of packets) (default: 128)
+   --rcvwnd value                set receive window size(num of packets) (default: 1024)
+   --datashard value             set reed-solomon erasure coding - datashard (default: 10)
+   --parityshard value           set reed-solomon erasure coding - parityshard (default: 3)
+   --dscp value                  set DSCP(6bit) (default: 0)
+   --nocomp                      disable compression
+   --help, -h                    show help
+   --version, -v                 print the version
+
+
+$ ./server_darwin_amd64 -h
+NAME:
+   kcptun - kcptun server
+
+USAGE:
+   server_darwin_amd64 [global options] command [command options] [arguments...]
+
+VERSION:
+   20160820
+
+COMMANDS:
+     help, h  Shows a list of commands or help for one command
+
+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]
+   --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)
+   --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
+   --help, -h                show help
+   --version, -v             print the version
 ```
-适用大部分ADSL接入（非对称上下行）的参数（实验环境电信100M ADSL）
-SERVER:   -mtu 1400 -sndwnd 2048 -rcvwnd 2048 -mode fast2
-CLIENT:   -mtu 1400 -sndwnd 256 -rcvwnd 2048 -mode fast2 -dscp 46
-其它带宽请按比例降低窗口，比如50M ADSL，把CLIENT的 -sndwnd -rcvwnd减掉一半,SERVER不变
+
+### *参数调整* :lollipop: 
+***两端参数必须一致的有:***
+* datashard
+* parityshard
+* nocomp
+* key
+* crypt
+
+其余为两边可独立设定的参数
+
+*简易自我调优方法*：
+> 第一步：同时在两端逐步增大client rcvwnd和server sndwnd;        
+> 第二步：尝试下载，观察如果带宽利用率（服务器＋客户端两端都要观察）接近物理带宽则停止，否则跳转到第一步。
+
+***注意：产生大量重传时，一定是窗口偏大了***
+
+*带宽计算公式*：
 ```
-*巭孬嫑乱动*        
+在不丢包的情况下，有最大-rcvwnd 个数据包在网络上正在向你传输，以平均数据包大小avgsize计算，在任意时刻，有：     
+
+		network_cap = rcvwnd*avgsize
+
+数据流向你，这个值再除以ping值(rtt)，等于最大带宽使用量。
+
+		max_bandwidth = network_cap/rtt = rcvwnd*avgsize/rtt
+		
+举例，设rcvwnd = 1024, avgsize = 1KB, rtt = 400ms，则：
+
+		max_bandwidth = 1024 * 1KB / 400ms = 2.5MB/s ~= 25Mbps
+		
+（注：以上计算不包括前向纠错的数据量）
+
+前向纠错是最大带宽量的一个固定比例增加：
+
+		max_bandwidth_fec = max_bandwidth*(datashard+parityshard)/datashard
+
+举例，设datashard = 10 , partiyshard = 3，则：
+
+		max_bandwidth_fec = max_bandwidth * (10 + 3) /10 = 1.3*max_bandwidth ＝ 1.3 * 25Mbps = 32.5Mbps
+```
+
+### *安全* :lollipop: 
+无论你上层如何加密，如果```-crypt none```，那么协议头部都是***明文***的，建议至少采用```-crypt aes-128```加密。
+
+注意: ```-crypt xor``` 也是不安全的，除非你知道你在做什么。
+
+### *内存控制* :lollipop: 
+路由器，手机等嵌入式设备通常对内存用量敏感，通过调节环境变量GOGC（例如GOGC=20)后启动client，可以降低内存使用。      
+参考：https://blog.golang.org/go15gc
+
+### *流量控制* :lollipop: 
+***必要性: 针对流量敏感的服务器，做双保险。***      
+
+> 基本原则: SERVER的发送速率不能超过ADSL下行带宽，否则只会浪费您的服务器带宽。  
+
+在server通过linux tc，可以限制服务器发送带宽。   
+举例:  用linux tc限制server发送带宽为32mbit/s: 
+```
+root@kcptun:~# cat tc.sh
+tc qdisc del dev eth0 root
+tc qdisc add dev eth0 root handle 1: htb
+tc class add dev eth0 parent 1: classid 1:1 htb rate 32mbit
+tc filter add dev eth0 protocol ip parent 1:0 prio 1 handle 10 fw flowid 1:1
+iptables -t mangle -A POSTROUTING -o eth0  -j MARK --set-mark 10
+root@kcptun:~#
+```
+其中eth0为网卡，有些服务器为ens3，有些为p2p1，通过ifconfig查询修改。
+
 
 ### *DSCP* :lollipop: 
 DSCP差分服务代码点（Differentiated Services Code Point），IETF于1998年12月发布了Diff-Serv（Differentiated Service）的QoS分类标准。它在每个数据包IP头部的服务类别TOS标识字节中，利用已使用的6比特和未使用的2比特，通过编码值来区分优先级。     
-常用DSCP值可以参考[Wikipedia DSCP](https://en.wikipedia.org/wiki/Differentiated_services#Commonly_used_DSCP_values)，至于有没有用，完全取决于数据包经过的设备。
+常用DSCP值可以参考[Wikipedia DSCP](https://en.wikipedia.org/wiki/Differentiated_services#Commonly_used_DSCP_values)，至于有没有用，完全取决于数据包经过的设备。 
+
+通过 ```-dscp ``` 参数指定dscp值，两端可分别设定。
+
+### *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。
+
+![reed-solomon](rs.png)
+
+通过参数```-datashard 10 -parityshard 3``` 在两端同时设定。
+
+### *Snappy数据流压缩* :lollipop: 
+> Snappy is a compression/decompression library. It does not aim for maximum
+> compression, or compatibility with any other compression library; instead,
+> it aims for very high speeds and reasonable compression. For instance,
+> compared to the fastest mode of zlib, Snappy is an order of magnitude faster
+> for most inputs, but the resulting compressed files are anywhere from 20% to
+> 100% bigger.
+
+> Reference: http://google.github.io/snappy/
+
+通过参数 ```-nocomp``` 在两端同时设定以关闭压缩。
+> 提示: 关闭压缩可能会降低延迟。
 
 ### *内置模式* :lollipop: 
 响应速度:     
@@ -54,13 +205,7 @@ DSCP差分服务代码点（Differentiated Services Code Point），IETF于1998
 ```
  -mode manual -nodelay 1 -resend 2 -nc 1 -interval 20
 ```
-
-### *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。
-
-![reed-solomon](rs.png)
-
-通过```-datashard 10 -parityshard 3``` 可以调整Reed Solomon参数。
+高丢包率的网络建议采用fast2, 低丢包率的网络，建议采用normal。
 
 ### *SNMP* :lollipop:
 ```go
@@ -91,21 +236,39 @@ type Snmp struct {
 使用```kill -SIGUSR1 pid``` 可以在控制台打印出SNMP信息，通常用于精细调整***当前链路的有效载荷比***。        
 观察```RetransSegs,FastRetransSegs,LostSegs,OutSegs```这几者的数值比例，用于参考调整```-mode manual,fec```的参数。        
 
-### *性能对比* :lollipop:
-```
-root@vultr:~# iperf -s
-------------------------------------------------------------
-Server listening on TCP port 5001
-TCP window size: 4.00 MByte (default)
-------------------------------------------------------------
-[  4] local 172.7.7.1 port 5001 connected with 172.7.7.2 port 55453
-[ ID] Interval       Transfer     Bandwidth
-[  4]  0.0-18.0 sec  5.50 MBytes  2.56 Mbits/sec     <-- connection via kcptun
-[  5] local 45.32.xxx.xxx port 5001 connected with 218.88.xxx.xxx port 17220
-[  5]  0.0-17.9 sec  2.12 MBytes   997 Kbits/sec     <-- direct connnection via tcp
-```
+### *故障排除* :lollipop:
+> Q: 客户端和服务器端***皆无*** ```stream opened```信息。       
+> A: 连接客户端程序的端口设置错误。     
+
+> Q: 客户端有 ```stream opened```信息，服务器端没有。     
+> A: 连接服务器的端口设置错误，或者被防火墙拦截。     
+
+> Q: 客户端服务器***皆有*** ```stream opened```信息，但无法通信。      
+> A: 上层软件的设定错误。     
 
 ### *免责申明* :warning:
 用户以各种方式使用本软件（包括但不限于修改使用、直接使用、通过第三方使用）的过程中，不得以任何方式利用本软件直接或间接从事违反中国法律、以及社会公德的行为。软件的使用者需对自身行为负责，因使用软件引发的一切纠纷，由使用者承担全部法律及连带责任。作者不承担任何法律及连带责任。       
 
 对免责声明的解释、修改及更新权均属于作者本人所有。
+
+### *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。     
+
+```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** 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.
+2. https://github.com/klauspost/reedsolomon -- Reed-Solomon Erasure Coding in Go.
+3. https://en.wikipedia.org/wiki/Differentiated_services -- DSCP.
+4. http://google.github.io/snappy/ -- A fast compressor/decompressor.
+5. https://www.backblaze.com/blog/reed-solomon/ -- Reed-Solomon Explained.
+6. http://www.qualcomm.cn/products/raptorq -- RaptorQ Forward Error Correction Scheme for Object Delivery.
+7. https://en.wikipedia.org/wiki/PBKDF2 -- Key stretching.
+8. http://blog.appcanary.com/2016/encrypt-or-compress.html -- Should you encrypt or compress first?
+9. https://github.com/hashicorp/yamux -- Connection multiplexing library.
+10. https://tools.ietf.org/html/rfc6937 -- Proportional Rate Reduction for TCP.
+11. https://tools.ietf.org/html/rfc5827 -- Early Retransmit for TCP and Stream Control Transmission Protocol (SCTP).
+12. http://http2.github.io/ -- What is HTTP/2?
+13. http://www.lartc.org/LARTC-zh_CN.GB2312.pdf -- Linux Advanced Routing & Traffic Control

build-release.sh

@@ -12,6 +12,7 @@ fi
 
 VERSION=`date -u +%Y%m%d`
 LDFLAGS="-X main.VERSION=$VERSION -s -w"
+GCFLAGS="-B"
 
 OSES=(linux darwin windows freebsd)
 ARCHS=(amd64 386)
@@ -22,8 +23,8 @@ for os in ${OSES[@]}; do
 		then
 			suffix=".exe"
 		fi
-		env GOOS=$os GOARCH=$arch go build -ldflags "$LDFLAGS" -o client_${os}_${arch}${suffix} github.com/xtaci/kcptun/client
-		env GOOS=$os GOARCH=$arch go build -ldflags "$LDFLAGS" -o server_${os}_${arch}${suffix} github.com/xtaci/kcptun/server
+		env CGO_ENABLED=0 GOOS=$os GOARCH=$arch go build -ldflags "$LDFLAGS" -gcflags "$GCFLAGS" -o client_${os}_${arch}${suffix} github.com/xtaci/kcptun/client
+		env CGO_ENABLED=0 GOOS=$os GOARCH=$arch go build -ldflags "$LDFLAGS" -gcflags "$GCFLAGS" -o server_${os}_${arch}${suffix} github.com/xtaci/kcptun/server
 		if $UPX; then upx -9 client_${os}_${arch}${suffix} server_${os}_${arch}${suffix};fi
 		tar -zcf kcptun-${os}-${arch}-$VERSION.tar.gz client_${os}_${arch}${suffix} server_${os}_${arch}${suffix}
 		$MD5 kcptun-${os}-${arch}-$VERSION.tar.gz
@@ -33,8 +34,8 @@ done
 # ARM
 ARMS=(5 6 7)
 for v in ${ARMS[@]}; do
-	env GOOS=linux GOARCH=arm GOARM=$v go build -ldflags "$LDFLAGS" -o client_linux_arm$v  github.com/xtaci/kcptun/client
-	env GOOS=linux GOARCH=arm GOARM=$v go build -ldflags "$LDFLAGS" -o server_linux_arm$v  github.com/xtaci/kcptun/server
+	env CGO_ENABLED=0 GOOS=linux GOARCH=arm GOARM=$v go build -ldflags "$LDFLAGS" -gcflags "$GCFLAGS" -o client_linux_arm$v  github.com/xtaci/kcptun/client
+	env CGO_ENABLED=0 GOOS=linux GOARCH=arm GOARM=$v go build -ldflags "$LDFLAGS" -gcflags "$GCFLAGS" -o server_linux_arm$v  github.com/xtaci/kcptun/server
 done
 if $UPX; then upx -9 client_linux_arm* server_linux_arm*;fi
 tar -zcf kcptun-linux-arm-$VERSION.tar.gz client_linux_arm* server_linux_arm*

client/config.go

@@ -0,0 +1,41 @@
+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"`
+}
+
+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

@@ -12,14 +12,17 @@ import (
 	"golang.org/x/crypto/pbkdf2"
 
 	"github.com/golang/snappy"
-	"github.com/hashicorp/yamux"
+	"github.com/pkg/errors"
 	"github.com/urfave/cli"
-	"github.com/xtaci/kcp-go"
+	kcp "github.com/xtaci/kcp-go"
+	"github.com/xtaci/smux"
 )
 
 var (
+	// VERSION is injected by buildflags
 	VERSION = "SELFBUILD"
-	SALT    = "kcp-go"
+	// SALT is use for pbkdf2 key expansion
+	SALT = "kcp-go"
 )
 
 type compStream struct {
@@ -78,16 +81,20 @@ func handleClient(p1, p2 io.ReadWriteCloser) {
 
 func checkError(err error) {
 	if err != nil {
-		log.Println(err)
+		log.Printf("%+v\n", err)
 		os.Exit(-1)
 	}
 }
 
 func main() {
 	rand.Seed(int64(time.Now().Nanosecond()))
+	if VERSION == "SELFBUILD" {
+		// add more log flags for debugging
+		log.SetFlags(log.LstdFlags | log.Lshortfile)
+	}
 	myApp := cli.NewApp()
 	myApp.Name = "kcptun"
-	myApp.Usage = "kcptun client"
+	myApp.Usage = "client(with SMUX)"
 	myApp.Version = VERSION
 	myApp.Flags = []cli.Flag{
 		cli.StringFlag{
@@ -103,28 +110,33 @@ func main() {
 		cli.StringFlag{
 			Name:   "key",
 			Value:  "it's a secrect",
-			Usage:  "key for communcation, must be the same as kcptun server",
+			Usage:  "pre-shared secret between client and server",
 			EnvVar: "KCPTUN_KEY",
 		},
 		cli.StringFlag{
 			Name:  "crypt",
 			Value: "aes",
-			Usage: "methods for encryption: aes, tea, xor, none",
+			Usage: "aes, aes-128, aes-192, salsa20, blowfish, twofish, cast5, 3des, tea, xtea, xor, none",
 		},
 		cli.StringFlag{
 			Name:  "mode",
 			Value: "fast",
-			Usage: "mode for communication: fast3, fast2, fast, normal",
+			Usage: "profiles: fast3, fast2, fast, normal",
 		},
 		cli.IntFlag{
 			Name:  "conn",
 			Value: 1,
-			Usage: "establish N physical connections as specified by 'conn' to server",
+			Usage: "set num of UDP connections to server",
+		},
+		cli.IntFlag{
+			Name:  "autoexpire",
+			Value: 0,
+			Usage: "set auto expiration time(in seconds) for a single UDP connection, 0 to disable",
 		},
 		cli.IntFlag{
 			Name:  "mtu",
 			Value: 1350,
-			Usage: "set MTU of UDP packets, suggest 'tracepath' to discover path mtu",
+			Usage: "set maximum transmission unit for UDP packets",
 		},
 		cli.IntFlag{
 			Name:  "sndwnd",
@@ -136,10 +148,6 @@ func main() {
 			Value: 1024,
 			Usage: "set receive window size(num of packets)",
 		},
-		cli.BoolFlag{
-			Name:  "nocomp",
-			Usage: "disable compression",
-		},
 		cli.IntFlag{
 			Name:  "datashard",
 			Value: 10,
@@ -150,15 +158,20 @@ func main() {
 			Value: 3,
 			Usage: "set reed-solomon erasure coding - parityshard",
 		},
-		cli.BoolFlag{
-			Name:  "acknodelay",
-			Usage: "flush ack immediately when a packet is received",
-		},
 		cli.IntFlag{
 			Name:  "dscp",
 			Value: 0,
 			Usage: "set DSCP(6bit)",
 		},
+		cli.BoolFlag{
+			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,
@@ -179,98 +192,204 @@ func main() {
 			Value:  0,
 			Hidden: true,
 		},
+		cli.IntFlag{
+			Name:   "sockbuf",
+			Value:  4194304, // socket buffer size in bytes
+			Hidden: true,
+		},
+		cli.IntFlag{
+			Name:   "keepalive",
+			Value:  10, // nat keepalive interval in seconds
+			Hidden: true,
+		},
+		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) {
+	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")
+
+		if c.String("c") != "" {
+			err := parseJSONConfig(&config, c.String("c"))
+			checkError(err)
+		}
+
+		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)
-		pass := pbkdf2.Key([]byte(c.String("key")), []byte(SALT), 4096, 32, sha1.New)
 
-		// 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
+		pass := pbkdf2.Key([]byte(config.Key), []byte(SALT), 4096, 32, sha1.New)
+		var block kcp.BlockCrypt
+		switch config.Crypt {
+		case "tea":
+			block, _ = kcp.NewTEABlockCrypt(pass[:16])
+		case "xor":
+			block, _ = kcp.NewSimpleXORBlockCrypt(pass)
+		case "none":
+			block, _ = kcp.NewNoneBlockCrypt(pass)
+		case "aes-128":
+			block, _ = kcp.NewAESBlockCrypt(pass[:16])
+		case "aes-192":
+			block, _ = kcp.NewAESBlockCrypt(pass[:24])
+		case "blowfish":
+			block, _ = kcp.NewBlowfishBlockCrypt(pass)
+		case "twofish":
+			block, _ = kcp.NewTwofishBlockCrypt(pass)
+		case "cast5":
+			block, _ = kcp.NewCast5BlockCrypt(pass[:16])
+		case "3des":
+			block, _ = kcp.NewTripleDESBlockCrypt(pass[:24])
+		case "xtea":
+			block, _ = kcp.NewXTEABlockCrypt(pass[:16])
+		case "salsa20":
+			block, _ = kcp.NewSalsa20BlockCrypt(pass)
+		default:
+			config.Crypt = "aes"
+			block, _ = kcp.NewAESBlockCrypt(pass)
 		}
 
 		log.Println("listening on:", listener.Addr())
-		log.Println("encryption:", c.String("crypt"))
-		log.Println("nodelay parameters:", nodelay, interval, resend, nc)
-		log.Println("remote address:", c.String("remoteaddr"))
-		log.Println("sndwnd:", c.Int("sndwnd"), "rcvwnd:", c.Int("rcvwnd"))
-		log.Println("compression:", !c.Bool("nocomp"))
-		log.Println("mtu:", c.Int("mtu"))
-		log.Println("datashard:", c.Int("datashard"), "parityshard:", c.Int("parityshard"))
-		log.Println("acknodelay:", c.Bool("acknodelay"))
-		log.Println("dscp:", c.Int("dscp"))
-		log.Println("conn:", c.Int("conn"))
+		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)
 
-		createConn := func() *yamux.Session {
-			var block kcp.BlockCrypt
-			switch c.String("crypt") {
-			case "tea":
-				block, _ = kcp.NewTEABlockCrypt(pass[:16])
-			case "xor":
-				block, _ = kcp.NewSimpleXORBlockCrypt(pass)
-			case "none":
-				block, _ = kcp.NewNoneBlockCrypt(pass)
-			default:
-				block, _ = kcp.NewAESBlockCrypt(pass)
+		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(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(config.DSCP); err != nil {
+				log.Println("SetDSCP:", err)
+			}
+			if err := kcpconn.SetReadBuffer(config.SockBuf); err != nil {
+				log.Println("SetReadBuffer:", err)
+			}
+			if err := kcpconn.SetWriteBuffer(config.SockBuf); err != nil {
+				log.Println("SetWriteBuffer:", err)
 			}
-			kcpconn, err := kcp.DialWithOptions(c.String("remoteaddr"), block, c.Int("datashard"), c.Int("parityshard"))
-			checkError(err)
-			kcpconn.SetNoDelay(nodelay, interval, resend, nc)
-			kcpconn.SetWindowSize(c.Int("sndwnd"), c.Int("rcvwnd"))
-			kcpconn.SetMtu(c.Int("mtu"))
-			kcpconn.SetACKNoDelay(c.Bool("acknodelay"))
-			kcpconn.SetDSCP(c.Int("dscp"))
 
 			// stream multiplex
-			config := &yamux.Config{
-				AcceptBacklog:          256,
-				EnableKeepAlive:        true,
-				KeepAliveInterval:      30 * time.Second,
-				ConnectionWriteTimeout: 30 * time.Second,
-				MaxStreamWindowSize:    16777216,
-				LogOutput:              os.Stderr,
-			}
-			var session *yamux.Session
-			if c.Bool("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)
 			}
+			if err != nil {
+				return nil, errors.Wrap(err, "createConn()")
+			}
+			return session, nil
+		}
+
+		// 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 *smux.Session
+			ttl     time.Time
+		}, numconn)
+
+		for k := range muxes {
+			sess, err := createConn()
 			checkError(err)
-			return session
-		}
-
-		numconn := uint16(c.Int("conn"))
-		var muxes []*yamux.Session
-		for i := uint16(0); i < numconn; i++ {
-			muxes = append(muxes, createConn())
+			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(config.SockBuf); err != nil {
+				log.Println("TCP SetReadBuffer:", err)
+			}
+			if err := p1.SetWriteBuffer(config.SockBuf); err != nil {
+				log.Println("TCP SetWriteBuffer:", err)
+			}
 			checkError(err)
-			mux := muxes[rr%numconn]
-			p2, err := mux.Open()
-			if err != nil { // yamux failure
-				log.Println(err)
-				p1.Close()
-				mux.Close()
-				muxes[rr%numconn] = createConn()
-				continue
+			idx := rr % numconn
+
+		OPEN_P2:
+			// do auto expiration
+			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.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)
 			rr++
@@ -278,3 +397,36 @@ 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
+		}
+	}
+}

client/signal.go

@@ -8,7 +8,7 @@ import (
 	"os/signal"
 	"syscall"
 
-	"github.com/xtaci/kcp-go"
+	kcp "github.com/xtaci/kcp-go"
 )
 
 func init() {

server/config.go

@@ -0,0 +1,39 @@
+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"`
+}
+
+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

@@ -12,14 +12,16 @@ import (
 	"golang.org/x/crypto/pbkdf2"
 
 	"github.com/golang/snappy"
-	"github.com/hashicorp/yamux"
 	"github.com/urfave/cli"
-	"github.com/xtaci/kcp-go"
+	kcp "github.com/xtaci/kcp-go"
+	"github.com/xtaci/smux"
 )
 
 var (
+	// VERSION is injected by buildflags
 	VERSION = "SELFBUILD"
-	SALT    = "kcp-go"
+	// SALT is use for pbkdf2 key expansion
+	SALT = "kcp-go"
 )
 
 type compStream struct {
@@ -51,35 +53,33 @@ func newCompStream(conn net.Conn) *compStream {
 }
 
 // handle multiplex-ed connection
-func handleMux(conn io.ReadWriteCloser, target string) {
+func handleMux(conn io.ReadWriteCloser, config *Config) {
 	// stream multiplex
-	var mux *yamux.Session
-	config := &yamux.Config{
-		AcceptBacklog:          256,
-		EnableKeepAlive:        true,
-		KeepAliveInterval:      30 * time.Second,
-		ConnectionWriteTimeout: 30 * time.Second,
-		MaxStreamWindowSize:    16777216,
-		LogOutput:              os.Stderr,
-	}
-	m, 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
 	}
-	mux = m
 	defer mux.Close()
-
 	for {
-		p1, err := mux.Accept()
+		p1, err := mux.AcceptStream()
 		if err != nil {
 			log.Println(err)
 			return
 		}
-		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(config.SockBuf); err != nil {
+			log.Println("TCP SetReadBuffer:", err)
+		}
+		if err := p2.(*net.TCPConn).SetWriteBuffer(config.SockBuf); err != nil {
+			log.Println("TCP SetWriteBuffer:", err)
 		}
 		go handleClient(p1, p2)
 	}
@@ -111,11 +111,22 @@ 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" {
+		// add more log flags for debugging
+		log.SetFlags(log.LstdFlags | log.Lshortfile)
+	}
 	myApp := cli.NewApp()
 	myApp.Name = "kcptun"
-	myApp.Usage = "kcptun server"
+	myApp.Usage = "server(with SMUX)"
 	myApp.Version = VERSION
 	myApp.Flags = []cli.Flag{
 		cli.StringFlag{
@@ -131,23 +142,23 @@ func main() {
 		cli.StringFlag{
 			Name:   "key",
 			Value:  "it's a secrect",
-			Usage:  "key for communcation, must be the same as kcptun client",
+			Usage:  "pre-shared secret between client and server",
 			EnvVar: "KCPTUN_KEY",
 		},
 		cli.StringFlag{
 			Name:  "crypt",
 			Value: "aes",
-			Usage: "methods for encryption: aes, tea, xor, none",
+			Usage: "aes, aes-128, aes-192, salsa20, blowfish, twofish, cast5, 3des, tea, xtea, xor, none",
 		},
 		cli.StringFlag{
 			Name:  "mode",
 			Value: "fast",
-			Usage: "mode for communication: fast3, fast2, fast, normal",
+			Usage: "profiles: fast3, fast2, fast, normal",
 		},
 		cli.IntFlag{
 			Name:  "mtu",
 			Value: 1350,
-			Usage: "set MTU of UDP packets, suggest 'tracepath' to discover path mtu",
+			Usage: "set maximum transmission unit for UDP packets",
 		},
 		cli.IntFlag{
 			Name:  "sndwnd",
@@ -159,10 +170,6 @@ func main() {
 			Value: 1024,
 			Usage: "set receive window size(num of packets)",
 		},
-		cli.BoolFlag{
-			Name:  "nocomp",
-			Usage: "disable compression",
-		},
 		cli.IntFlag{
 			Name:  "datashard",
 			Value: 10,
@@ -173,15 +180,20 @@ func main() {
 			Value: 3,
 			Usage: "set reed-solomon erasure coding - parityshard",
 		},
-		cli.BoolFlag{
-			Name:  "acknodelay",
-			Usage: "flush ack immediately when a packet is received",
-		},
 		cli.IntFlag{
 			Name:  "dscp",
 			Value: 0,
 			Usage: "set DSCP(6bit)",
 		},
+		cli.BoolFlag{
+			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,
@@ -202,63 +214,133 @@ func main() {
 			Value:  0,
 			Hidden: true,
 		},
+		cli.IntFlag{
+			Name:   "sockbuf",
+			Value:  4194304, // socket buffer size in bytes
+			Hidden: true,
+		},
+		cli.IntFlag{
+			Name:   "keepalive",
+			Value:  10, // nat keepalive interval in seconds
+			Hidden: true,
+		},
+		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) {
-		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
+	myApp.Action = func(c *cli.Context) error {
+		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")
+
+		if c.String("c") != "" {
+			//Now only support json config file
+			err := parseJSONConfig(&config, c.String("c"))
+			checkError(err)
 		}
 
-		pass := pbkdf2.Key([]byte(c.String("key")), []byte(SALT), 4096, 32, sha1.New)
+		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 c.String("crypt") {
+		switch config.Crypt {
 		case "tea":
 			block, _ = kcp.NewTEABlockCrypt(pass[:16])
 		case "xor":
 			block, _ = kcp.NewSimpleXORBlockCrypt(pass)
 		case "none":
 			block, _ = kcp.NewNoneBlockCrypt(pass)
+		case "aes-128":
+			block, _ = kcp.NewAESBlockCrypt(pass[:16])
+		case "aes-192":
+			block, _ = kcp.NewAESBlockCrypt(pass[:24])
+		case "blowfish":
+			block, _ = kcp.NewBlowfishBlockCrypt(pass)
+		case "twofish":
+			block, _ = kcp.NewTwofishBlockCrypt(pass)
+		case "cast5":
+			block, _ = kcp.NewCast5BlockCrypt(pass[:16])
+		case "3des":
+			block, _ = kcp.NewTripleDESBlockCrypt(pass[:24])
+		case "xtea":
+			block, _ = kcp.NewXTEABlockCrypt(pass[:16])
+		case "salsa20":
+			block, _ = kcp.NewSalsa20BlockCrypt(pass)
 		default:
+			config.Crypt = "aes"
 			block, _ = kcp.NewAESBlockCrypt(pass)
 		}
 
-		lis, err := kcp.ListenWithOptions(c.String("listen"), block, c.Int("datashard"), c.Int("parityshard"))
-		if err != nil {
-			log.Fatal(err)
-		}
-		log.Println("listening on ", lis.Addr())
-		log.Println("encryption:", c.String("crypt"))
-		log.Println("nodelay parameters:", nodelay, interval, resend, nc)
-		log.Println("sndwnd:", c.Int("sndwnd"), "rcvwnd:", c.Int("rcvwnd"))
-		log.Println("compression:", !c.Bool("nocomp"))
-		log.Println("mtu:", c.Int("mtu"))
-		log.Println("datashard:", c.Int("datashard"), "parityshard:", c.Int("parityshard"))
-		log.Println("acknodelay:", c.Bool("acknodelay"))
-		log.Println("dscp:", c.Int("dscp"))
-		for {
-			if conn, err := lis.Accept(); err == nil {
-				log.Println("remote address:", conn.RemoteAddr())
-				conn.SetNoDelay(nodelay, interval, resend, nc)
-				conn.SetMtu(c.Int("mtu"))
-				conn.SetWindowSize(c.Int("sndwnd"), c.Int("rcvwnd"))
-				conn.SetACKNoDelay(c.Bool("acknodelay"))
-				conn.SetDSCP(c.Int("dscp"))
+		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)
 
-				if c.Bool("nocomp") {
-					go handleMux(conn, c.String("target"))
+		if err := lis.SetDSCP(config.DSCP); err != nil {
+			log.Println("SetDSCP:", err)
+		}
+		if err := lis.SetReadBuffer(config.SockBuf); err != nil {
+			log.Println("SetReadBuffer:", err)
+		}
+		if err := lis.SetWriteBuffer(config.SockBuf); err != nil {
+			log.Println("SetWriteBuffer:", err)
+		}
+		for {
+			if conn, err := lis.AcceptKCP(); err == nil {
+				log.Println("remote address:", conn.RemoteAddr())
+				conn.SetStreamMode(true)
+				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 config.NoComp {
+					go handleMux(conn, &config)
 				} else {
-					go handleMux(newCompStream(conn), c.String("target"))
+					go handleMux(newCompStream(conn), &config)
 				}
 			} else {
-				log.Println(err)
+				log.Printf("%+v", err)
 			}
 		}
 	}

server/signal.go

@@ -8,7 +8,7 @@ import (
 	"os/signal"
 	"syscall"
 
-	"github.com/xtaci/kcp-go"
+	kcp "github.com/xtaci/kcp-go"
 )
 
 func init() {