add a max ttl for session in scavenger

This reverts commit cb0f299263.

.github/ISSUE_TEMPLATE

@@ -1,15 +1,3 @@
-问问题前先搜索ISSUE，并搞清楚下面的问题:
-
-1. 检查 ```-key xxx``` 至少三遍, ***保证***两边一致。
-2. 保证```-nocomp, -datashard, -parityshard,  -key, -crypt```两边一致。
-3. 是否在服务器端，正确设定了转发的目标服务器地址 ***--target***。
-4. 如果第3条不确定，尝试在服务器上telnet target port试试。
-5. 防火墙是否关闭了UDP通信。
-6. 两端的版本是否一致？
-7. 是不是最新版本？
-8. 两端分别是什么操作系统？
-9. 两端的输出日志是什么？
-
 Before firing issue, make sure you figured out the following common questions.
 
 PLEASE DO SEARCH FIRST.
@@ -23,5 +11,3 @@ PLEASE DO SEARCH FIRST.
 7. Are you using the **latest release**?
 8. Which **OS** do you use?
 9. Which end for this issue related to, **client or server**?
-
-

.travis.yml

@@ -1,6 +1,6 @@
 language: go
 go:
-    - 1.9
+    - 1.6
 before_install:
     - go get github.com/mattn/goveralls
     - go get golang.org/x/tools/cmd/cover

Dockerfile

@@ -3,6 +3,6 @@ MAINTAINER xtaci <daniel820313@gmail.com>
 RUN apk update && \
     apk upgrade && \
     apk add git
-RUN go get -ldflags "-X main.VERSION=$(date -u +%Y%m%d) -s -w" github.com/xtaci/kcptun/client && go get -ldflags "-X main.VERSION=$(date -u +%Y%m%d) -s -w" github.com/xtaci/kcptun/server
+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

@@ -1,7 +1,5 @@
-# <img src="logo.png" alt="kcptun" height="54px" /> 
-
-[![Release][13]][14] [![Powered][17]][18] [![MIT licensed][11]][12] [![Build Status][3]][4] [![Go Report Card][5]][6] [![Downloads][15]][16] [![Docker][1]][2]
-
+# <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
@@ -18,196 +16,173 @@
 [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
 
-<img src="kcptun.png" alt="kcptun" height="300px"/>
-
-> *kcptun maintains a single website — [github.com/xtaci/kcptun](https://github.com/xtaci/kcptun). Any websites other than [github.com/xtaci/kcptun](https://github.com/xtaci/kcptun) are not endorsed by xtaci. kcptun won't publish anything on any social media.*
-
-### QuickStart
-
-Download precompiled [Releases](https://github.com/xtaci/kcptun/releases).
+***[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)
+[English Readme](README.en.md)
+### *快速设定* :lollipop:
 ```
-KCP Client: ./client_darwin_amd64 -r "KCP_SERVER_IP:4000" -l ":8388" -mode fast2
-KCP Server: ./server_linux_amd64 -t "TARGET_IP:8388" -l ":4000" -mode fast2
-```
-The above commands will establish port forwarding for 8388/tcp as:
-
-> Application -> **KCP Client(8388/tcp) -> KCP Server(4000/udp)** -> Target Server(8388/tcp) 
-
-Tunnels the original connection:
-
-> Application -> Target Server(8388/tcp) 
-
-### Install from source
-
-```
-$go get -u github.com/xtaci/kcptun/client
-$go get -u github.com/xtaci/kcptun/server
+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
 ```
 
-All precompiled releases are genereated from `build-release.sh` script.
-
-### Performance
-
+### *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
 
-### Basic Tuning Guide
-
-#### Improving Thoughput
-
-> **Q: I have a high speed network link, how to reach the maximum bandwidth?**        
-
-> **A:** Increase `-rcvwnd` on KCP Client and `-sndwnd` on KCP Server **simultaneously & gradually**, the mininum one decides the maximum transfer rate of the link, as `wnd * mtu / rtt`; Then try downloading something and to see if it meets your requirements. 
-(mtu is adjustable by `-mtu`)
-
-#### Improving Latency
-
-> **Q: I'm using kcptun for game, I don't want any lag happening.**    
-
-> **A:** Lag means packet loss for most of the time, lags can be improved by changing `-mode`.
-
-> eg: `-mode fast3`    
-
-> Aggresiveness/Responsiveness on retransmission for embeded modes are:
-
-> *fast3 > fast2 > fast > normal > default*
-
--
-
-### Expert Tuning Guide
-
-#### Overview
-
-<p align="left"><img src="layeredparams.png" alt="params" height="450px"/></p>
-
-#### Usage
-
+### *使用方法* :lollipop:
+在Mac OS X El Capitan下的帮助输出: 
 ```
 $ ./client_darwin_amd64 -h
 NAME:
-   kcptun - client(with SMUX)
+   kcptun - kcptun client
 
 USAGE:
    client_darwin_amd64 [global options] command [command options] [arguments...]
 
 VERSION:
-   20170120
+   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 between client and server (default: "it's a secrect") [$KCPTUN_KEY]
-   --crypt value                    aes, aes-128, aes-192, salsa20, blowfish, twofish, cast5, 3des, tea, xtea, xor, none (default: "aes")
-   --mode value                     profiles: fast3, fast2, fast, normal (default: "fast")
-   --conn value                     set num of UDP connections to server (default: 1)
-   --autoexpire value               set auto expiration time(in seconds) for a single UDP connection, 0 to disable (default: 0)
-   --mtu value                      set maximum transmission unit for UDP packets (default: 1350)
-   --sndwnd value                   set send window size(num of packets) (default: 128)
-   --rcvwnd value                   set receive window size(num of packets) (default: 512)
-   --datashard value, --ds value    set reed-solomon erasure coding - datashard (default: 10)
-   --parityshard value, --ps value  set reed-solomon erasure coding - parityshard (default: 3)
-   --dscp value                     set DSCP(6bit) (default: 0)
-   --nocomp                         disable compression
-   --snmplog value                  collect snmp to file, aware of timeformat in golang, like: ./snmp-20060102.log
-   --snmpperiod value               snmp collect period, in seconds (default: 60)
-   --log value                      specify a log file to output, default goes to stderr
-   -c value                         config from json file, which will override the command from shell
-   --help, -h                       show help
-   --version, -v                    print the version
+   --localaddr value, -l value   local listen address (default: ":12948")
+   --remoteaddr value, -r value  kcp server address (default: "vps:29900")
+   --key value                   pre-shared secret for client and server (default: "it's a secrect") [$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 - server(with SMUX)
+   kcptun - kcptun server
 
 USAGE:
    server_darwin_amd64 [global options] command [command options] [arguments...]
 
 VERSION:
-   20170120
+   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 between client and server (default: "it's a secrect") [$KCPTUN_KEY]
-   --crypt value                    aes, aes-128, aes-192, salsa20, blowfish, twofish, cast5, 3des, tea, xtea, xor, none (default: "aes")
-   --mode value                     profiles: fast3, fast2, fast, normal (default: "fast")
-   --mtu value                      set maximum transmission unit for UDP packets (default: 1350)
-   --sndwnd value                   set send window size(num of packets) (default: 1024)
-   --rcvwnd value                   set receive window size(num of packets) (default: 1024)
-   --datashard value, --ds value    set reed-solomon erasure coding - datashard (default: 10)
-   --parityshard value, --ps value  set reed-solomon erasure coding - parityshard (default: 3)
-   --dscp value                     set DSCP(6bit) (default: 0)
-   --nocomp                         disable compression
-   --snmplog value                  collect snmp to file, aware of timeformat in golang, like: ./snmp-20060102.log
-   --snmpperiod value               snmp collect period, in seconds (default: 60)
-   --log value                      specify a log file to output, default goes to stderr
-   -c value                         config from json file, which will override the command from shell
-   --help, -h                       show help
-   --version, -v                    print the version
+   --listen value, -l value  kcp server listen address (default: ":29900")
+   --target value, -t value  target server address (default: "127.0.0.1:12948")
+   --key value               pre-shared secret for client and server (default: "it's a secrect") [$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
 ```
 
-#### Forward Error Correction
+### *参数调整* :lollipop: 
+***两端参数必须一致的有:***
+* datashard
+* parityshard
+* nocomp
+* key
+* crypt
 
-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.
+其余为两边可独立设定的参数
 
-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.
+*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*：
+```
+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。 
+
+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)
 
-Setting parameters of RS-Code with ```-datashard m -parityshard n``` on **BOTH** KCP Client & KCP Server **MUST** be **IDENTICAL**.
-
-#### DSCP
-
-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.
-
-setting each side with ```-dscp value```, Here are some [Commonly used DSCP values](https://en.wikipedia.org/wiki/Differentiated_services#Commonly_used_DSCP_values).
-
-#### Security
-
-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 .
-
-`-crypt` and `-key` must be the same on both KCP Client & KCP Server.
-
-NOTICE: ```-crypt xor``` is also insecure, do not use this unless you know what you are doing.
-
-Benchmarks for crypto algorithms supported by kcptun:
-
-```
-BenchmarkAES128-4      	  200000	     11182 ns/op
-BenchmarkAES192-4      	  200000	     12699 ns/op
-BenchmarkAES256-4      	  100000	     13757 ns/op
-BenchmarkTEA-4         	   50000	     26441 ns/op
-BenchmarkSimpleXOR-4   	 3000000	       441 ns/op
-BenchmarkBlowfish-4    	   30000	     48036 ns/op
-BenchmarkNone-4        	20000000	       106 ns/op
-BenchmarkCast5-4       	   20000	     60222 ns/op
-BenchmarkTripleDES-4   	    2000	    878759 ns/op
-BenchmarkTwofish-4     	   20000	     68501 ns/op
-BenchmarkXTEA-4        	   20000	     77417 ns/op
-BenchmarkSalsa20-4     	  300000	      4998 ns/op
-```
-
-
-
-#### Memory Control
-
-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
-
-#### Compression
-
-kcptun has builtin snappy algorithms for compressing streams:
+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,
@@ -217,84 +192,83 @@ kcptun has builtin snappy algorithms for compressing streams:
 
 > Reference: http://google.github.io/snappy/
 
-Compression may save bandwidth for **PLAINTEXT** data, such as HTTP data.
+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。
 
-Compression is enabled by default, you can disable it by setting ```-nocomp``` on **BOTH** KCP Client & KCP Server **MUST** be **IDENTICAL**.
-
-#### SNMP
+### *内置模式* :lollipop: 
+响应速度:     
+*fast3 >* ***[fast2]*** *> fast > normal > default*        
+有效载荷比:     
+*default > normal > fast >* ***[fast2]*** *> fast3*       
+中间mode参数比较均衡，总之就是越快越浪费带宽，推荐模式 ***fast2***         
+更高级的 ***手动档*** 需要理解KCP协议，并通过 ***隐藏参数*** 调整，例如:
+```
+ -mode manual -nodelay 1 -resend 2 -nc 1 -interval 20
+```
+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
 // Snmp defines network statistics indicator
 type Snmp struct {
-    BytesSent        uint64 // raw bytes sent
-    BytesReceived    uint64
-    MaxConn          uint64
-    ActiveOpens      uint64
-    PassiveOpens     uint64
-    CurrEstab        uint64 // count of connections for now
-    InErrs           uint64 // udp read errors
-    InCsumErrors     uint64 // checksum errors from CRC32
-    KCPInErrors      uint64 // packet iput errors from kcp
-    InSegs           uint64
-    OutSegs          uint64
-    InBytes          uint64 // udp bytes received
-    OutBytes         uint64 // udp bytes sent
-    RetransSegs      uint64
-    FastRetransSegs  uint64
-    EarlyRetransSegs uint64
-    LostSegs         uint64 // number of segs infered as lost
-    RepeatSegs       uint64 // number of segs duplicated
-    FECRecovered     uint64 // correct packets recovered from FEC
-    FECErrs          uint64 // incorrect packets recovered from FEC
-    FECSegs          uint64 // FEC segments received
-    FECShortShards   uint64 // number of data shards that's not enough for recovery
+	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 `SIGUSR1` signal to KCP Client or KCP Server will dump SNMP information to console, just like `/proc/net/snmp`. You can use this information to do fine-grained tuning.
+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。        
 
-### Manual Control
+### *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。     
 
-https://github.com/skywind3000/kcp/blob/master/README.en.md#protocol-configuration
+> 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。     
 
-`-mode manual -nodelay 1 -interval 20 -resend 2 -nc 1`
+> 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。     
 
-Low-level KCP configuration can be altered by using manual mode like above, make sure you really **UNDERSTAND** what these means before doing **ANY** manual settings.
+### *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。
 
-### Identical Parmeters
+### *捐赠* :dollar:
+![donate](donate.png)          
 
-The parameters below **MUST** be **IDENTICAL** on **BOTH** side:
+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。     
 
-1. -key
-1. -crypt
-1. -nocomp
-1. -datashard
-1. -parityshard
-
-### References
+```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.
-1. https://github.com/xtaci/kcp-go/ -- A Production-Grade Reliable-UDP Library for golang
-1. https://github.com/klauspost/reedsolomon -- Reed-Solomon Erasure Coding in Go.
-1. https://en.wikipedia.org/wiki/Differentiated_services -- DSCP.
-1. http://google.github.io/snappy/ -- A fast compressor/decompressor.
-1. https://www.backblaze.com/blog/reed-solomon/ -- Reed-Solomon Explained.
-1. http://www.qualcomm.cn/products/raptorq -- RaptorQ Forward Error Correction Scheme for Object Delivery.
-1. https://en.wikipedia.org/wiki/PBKDF2 -- Key stretching.
-1. http://blog.appcanary.com/2016/encrypt-or-compress.html -- Should you encrypt or compress first?
-1. https://github.com/hashicorp/yamux -- Connection multiplexing library.
-1. https://tools.ietf.org/html/rfc6937 -- Proportional Rate Reduction for TCP.
-1. https://tools.ietf.org/html/rfc5827 -- Early Retransmit for TCP and Stream Control Transmission Protocol (SCTP).
-1. http://http2.github.io/ -- What is HTTP/2?
-1. http://www.lartc.org/ -- Linux Advanced Routing & Traffic Control
-1. https://en.wikipedia.org/wiki/Noisy-channel_coding_theorem -- Noisy channel coding theorem
-1. https://play.google.com/store/apps/details?id=com.k17game.k3 -- Battle Zone - Earth 2048, an online strategy game using kcp.
-
-Donate via ETH:
-
-Address: 0x2e4b43ab3d0983da282592571eef61ae5e60f726
-
-QR Code:
-
-![ETH](0x2e4b43ab3d0983da282592571eef61ae5e60f726.png)
+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

@@ -1,13 +1,8 @@
 #!/bin/bash
-sum="sha1sum"
-
-if ! hash sha1sum 2>/dev/null; then
-	if ! hash shasum 2>/dev/null; then
-		echo "I can't see 'sha1sum' or 'shasum'"
-		echo "Please install one of them!"
-		exit
-	fi
-	sum="shasum"
+MD5='md5sum'
+unamestr=`uname`
+if [[ "$unamestr" == 'Darwin' ]]; then
+	MD5='md5'
 fi
 
 UPX=false
@@ -17,7 +12,7 @@ fi
 
 VERSION=`date -u +%Y%m%d`
 LDFLAGS="-X main.VERSION=$VERSION -s -w"
-GCFLAGS=""
+GCFLAGS="-B"
 
 OSES=(linux darwin windows freebsd)
 ARCHS=(amd64 386)
@@ -32,7 +27,7 @@ for os in ${OSES[@]}; do
 		env CGO_ENABLED=0 GOOS=$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}
-		$sum kcptun-${os}-${arch}-$VERSION.tar.gz
+		$MD5 kcptun-${os}-${arch}-$VERSION.tar.gz
 	done
 done
 
@@ -44,16 +39,4 @@ for v in ${ARMS[@]}; do
 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*
-$sum kcptun-linux-arm-$VERSION.tar.gz
-
-#MIPS32LE
-env CGO_ENABLED=0 GOOS=linux GOARCH=mipsle go build -ldflags "$LDFLAGS" -gcflags "$GCFLAGS" -o client_linux_mipsle github.com/xtaci/kcptun/client
-env CGO_ENABLED=0 GOOS=linux GOARCH=mipsle go build -ldflags "$LDFLAGS" -gcflags "$GCFLAGS" -o server_linux_mipsle github.com/xtaci/kcptun/server
-env CGO_ENABLED=0 GOOS=linux GOARCH=mips go build -ldflags "$LDFLAGS" -gcflags "$GCFLAGS" -o client_linux_mips github.com/xtaci/kcptun/client
-env CGO_ENABLED=0 GOOS=linux GOARCH=mips go build -ldflags "$LDFLAGS" -gcflags "$GCFLAGS" -o server_linux_mips github.com/xtaci/kcptun/server
-
-if $UPX; then upx -9 client_linux_mips* server_linux_mips*;fi
-tar -zcf kcptun-linux-mipsle-$VERSION.tar.gz client_linux_mipsle server_linux_mipsle
-tar -zcf kcptun-linux-mips-$VERSION.tar.gz client_linux_mips server_linux_mips
-$sum kcptun-linux-mipsle-$VERSION.tar.gz
-$sum kcptun-linux-mips-$VERSION.tar.gz
+$MD5 kcptun-linux-arm-$VERSION.tar.gz

client/config.go

@@ -5,7 +5,6 @@ import (
 	"os"
 )
 
-// Config for client
 type Config struct {
 	LocalAddr    string `json:"localaddr"`
 	RemoteAddr   string `json:"remoteaddr"`
@@ -14,7 +13,6 @@ type Config struct {
 	Mode         string `json:"mode"`
 	Conn         int    `json:"conn"`
 	AutoExpire   int    `json:"autoexpire"`
-	ScavengeTTL  int    `json:"scavengettl"`
 	MTU          int    `json:"mtu"`
 	SndWnd       int    `json:"sndwnd"`
 	RcvWnd       int    `json:"rcvwnd"`
@@ -29,17 +27,18 @@ type Config struct {
 	NoCongestion int    `json:"nc"`
 	SockBuf      int    `json:"sockbuf"`
 	KeepAlive    int    `json:"keepalive"`
-	Log          string `json:"log"`
-	SnmpLog      string `json:"snmplog"`
-	SnmpPeriod   int    `json:"snmpperiod"`
 }
 
-func parseJSONConfig(config *Config, path string) error {
+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)
+	if err = json.NewDecoder(file).Decode(config); err != nil {
+		return err
+	}
+
+	return err
 }

client/main.go

@@ -2,8 +2,6 @@ package main
 
 import (
 	"crypto/sha1"
-	"encoding/csv"
-	"fmt"
 	"io"
 	"log"
 	"math/rand"
@@ -14,7 +12,6 @@ import (
 	"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/smux"
@@ -55,22 +52,24 @@ func newCompStream(conn net.Conn) *compStream {
 	return c
 }
 
-func handleClient(sess *smux.Session, p1 io.ReadWriteCloser) {
+func handleClient(p1, p2 io.ReadWriteCloser) {
 	log.Println("stream opened")
 	defer log.Println("stream closed")
 	defer p1.Close()
-	p2, err := sess.OpenStream()
-	if err != nil {
-		return
-	}
 	defer p2.Close()
 
 	// 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 {
@@ -121,7 +120,7 @@ func main() {
 		cli.StringFlag{
 			Name:  "mode",
 			Value: "fast",
-			Usage: "profiles: fast3, fast2, fast, normal, manual",
+			Usage: "profiles: fast3, fast2, fast, normal",
 		},
 		cli.IntFlag{
 			Name:  "conn",
@@ -133,11 +132,6 @@ func main() {
 			Value: 0,
 			Usage: "set auto expiration time(in seconds) for a single UDP connection, 0 to disable",
 		},
-		cli.IntFlag{
-			Name:  "scavengettl",
-			Value: 600,
-			Usage: "set how long an expired connection can live(in sec), -1 to disable",
-		},
 		cli.IntFlag{
 			Name:  "mtu",
 			Value: 1350,
@@ -150,16 +144,16 @@ func main() {
 		},
 		cli.IntFlag{
 			Name:  "rcvwnd",
-			Value: 512,
+			Value: 1024,
 			Usage: "set receive window size(num of packets)",
 		},
 		cli.IntFlag{
-			Name:  "datashard,ds",
+			Name:  "datashard",
 			Value: 10,
 			Usage: "set reed-solomon erasure coding - datashard",
 		},
 		cli.IntFlag{
-			Name:  "parityshard,ps",
+			Name:  "parityshard",
 			Value: 3,
 			Usage: "set reed-solomon erasure coding - parityshard",
 		},
@@ -184,7 +178,7 @@ func main() {
 		},
 		cli.IntFlag{
 			Name:   "interval",
-			Value:  50,
+			Value:  40,
 			Hidden: true,
 		},
 		cli.IntFlag{
@@ -207,21 +201,6 @@ func main() {
 			Value:  10, // nat keepalive interval in seconds
 			Hidden: true,
 		},
-		cli.StringFlag{
-			Name:  "snmplog",
-			Value: "",
-			Usage: "collect snmp to file, aware of timeformat in golang, like: ./snmp-20060102.log",
-		},
-		cli.IntFlag{
-			Name:  "snmpperiod",
-			Value: 60,
-			Usage: "snmp collect period, in seconds",
-		},
-		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
@@ -237,7 +216,6 @@ func main() {
 		config.Mode = c.String("mode")
 		config.Conn = c.Int("conn")
 		config.AutoExpire = c.Int("autoexpire")
-		config.ScavengeTTL = c.Int("scavengettl")
 		config.MTU = c.Int("mtu")
 		config.SndWnd = c.Int("sndwnd")
 		config.RcvWnd = c.Int("rcvwnd")
@@ -252,28 +230,17 @@ func main() {
 		config.NoCongestion = c.Int("nc")
 		config.SockBuf = c.Int("sockbuf")
 		config.KeepAlive = c.Int("keepalive")
-		config.Log = c.String("log")
-		config.SnmpLog = c.String("snmplog")
-		config.SnmpPeriod = c.Int("snmpperiod")
 
 		if c.String("c") != "" {
-			err := parseJSONConfig(&config, 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, 40, 2, 1
-		case "fast":
 			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":
@@ -330,25 +297,19 @@ func main() {
 		log.Println("keepalive:", config.KeepAlive)
 		log.Println("conn:", config.Conn)
 		log.Println("autoexpire:", config.AutoExpire)
-		log.Println("scavengettl:", config.ScavengeTTL)
-		log.Println("snmplog:", config.SnmpLog)
-		log.Println("snmpperiod:", config.SnmpPeriod)
 
 		smuxConfig := smux.DefaultConfig()
 		smuxConfig.MaxReceiveBuffer = config.SockBuf
-		smuxConfig.KeepAliveInterval = time.Duration(config.KeepAlive) * time.Second
 
-		createConn := func() (*smux.Session, error) {
+		createConn := func() *smux.Session {
 			kcpconn, err := kcp.DialWithOptions(config.RemoteAddr, block, config.DataShard, config.ParityShard)
-			if err != nil {
-				return nil, errors.Wrap(err, "createConn()")
-			}
+			checkError(err)
 			kcpconn.SetStreamMode(true)
-			kcpconn.SetWriteDelay(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)
@@ -367,23 +328,8 @@ func main() {
 			} else {
 				session, err = smux.Client(newCompStream(kcpconn), smuxConfig)
 			}
-			if err != nil {
-				return nil, errors.Wrap(err, "createConn()")
-			}
-			log.Println("connection:", kcpconn.LocalAddr(), "->", kcpconn.RemoteAddr())
-			return session, nil
-		}
-
-		// wait until a connection is ready
-		waitConn := func() *smux.Session {
-			for {
-				if session, err := createConn(); err == nil {
-					return session
-				} else {
-					log.Println("re-connecting:", err)
-					time.Sleep(time.Second)
-				}
-			}
+			checkError(err)
+			return session
 		}
 
 		numconn := uint16(config.Conn)
@@ -393,30 +339,41 @@ func main() {
 		}, numconn)
 
 		for k := range muxes {
-			muxes[k].session = waitConn()
+			muxes[k].session = createConn()
 			muxes[k].ttl = time.Now().Add(time.Duration(config.AutoExpire) * time.Second)
 		}
 
 		chScavenger := make(chan *smux.Session, 128)
-		go scavenger(chScavenger, config.ScavengeTTL)
-		go snmpLogger(config.SnmpLog, config.SnmpPeriod)
+		go scavenger(chScavenger)
 		rr := uint16(0)
 		for {
 			p1, err := listener.AcceptTCP()
-			if err != nil {
-				log.Fatalln(err)
+			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)
 			idx := rr % numconn
 
-			// do auto expiration && reconnection
-			if muxes[idx].session.IsClosed() || (config.AutoExpire > 0 && time.Now().After(muxes[idx].ttl)) {
+		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].session = createConn()
 				muxes[idx].ttl = time.Now().Add(time.Duration(config.AutoExpire) * time.Second)
 			}
 
-			go handleClient(muxes[idx].session, p1)
+			// do session open
+			p2, err := muxes[idx].session.OpenStream()
+			if err != nil { // mux failure
+				chScavenger <- muxes[idx].session
+				muxes[idx].session = createConn()
+				muxes[idx].ttl = time.Now().Add(time.Duration(config.AutoExpire) * time.Second)
+				goto OPEN_P2
+			}
+			go handleClient(p1, p2)
 			rr++
 		}
 	}
@@ -425,27 +382,27 @@ func main() {
 
 type scavengeSession struct {
 	session *smux.Session
-	ts      time.Time
+	ttl     time.Time
 }
 
-func scavenger(ch chan *smux.Session, ttl int) {
-	ticker := time.NewTicker(time.Second)
+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()})
-			log.Println("session marked as expired")
 		case <-ticker.C:
 			var newList []scavengeSession
 			for k := range sessionList {
 				s := sessionList[k]
-				if s.session.NumStreams() == 0 || s.session.IsClosed() {
-					log.Println("session normally closed")
-					s.session.Close()
-				} else if ttl >= 0 && time.Since(s.ts) >= time.Duration(ttl)*time.Second {
-					log.Println("session reached scavenge ttl")
+				if s.session.NumStreams() == 0 || s.session.IsClosed() || time.Now().Sub(s.ttl) > maxScavengeTTL {
+					log.Println("session scavenged")
 					s.session.Close()
 				} else {
 					newList = append(newList, sessionList[k])
@@ -455,34 +412,3 @@ func scavenger(ch chan *smux.Session, ttl int) {
 		}
 	}
 }
-
-func snmpLogger(path string, interval int) {
-	if path == "" || interval == 0 {
-		return
-	}
-	ticker := time.NewTicker(time.Duration(interval) * time.Second)
-	defer ticker.Stop()
-	for {
-		select {
-		case <-ticker.C:
-			f, err := os.OpenFile(time.Now().Format(path), os.O_RDWR|os.O_CREATE|os.O_APPEND, 0666)
-			if err != nil {
-				log.Println(err)
-				return
-			}
-			w := csv.NewWriter(f)
-			// write header in empty file
-			if stat, err := f.Stat(); err == nil && stat.Size() == 0 {
-				if err := w.Write(append([]string{"Unix"}, kcp.DefaultSnmp.Header()...)); err != nil {
-					log.Println(err)
-				}
-			}
-			if err := w.Write(append([]string{fmt.Sprint(time.Now().Unix())}, kcp.DefaultSnmp.ToSlice()...)); err != nil {
-				log.Println(err)
-			}
-			kcp.DefaultSnmp.Reset()
-			w.Flush()
-			f.Close()
-		}
-	}
-}

client/signal.go

@@ -18,7 +18,6 @@ func init() {
 func sigHandler() {
 	ch := make(chan os.Signal, 1)
 	signal.Notify(ch, syscall.SIGUSR1)
-	signal.Ignore(syscall.SIGPIPE)
 
 	for {
 		switch <-ch {

server/config.go

@@ -5,7 +5,6 @@ import (
 	"os"
 )
 
-// Config for server
 type Config struct {
 	Listen       string `json:"listen"`
 	Target       string `json:"target"`
@@ -26,18 +25,18 @@ type Config struct {
 	NoCongestion int    `json:"nc"`
 	SockBuf      int    `json:"sockbuf"`
 	KeepAlive    int    `json:"keepalive"`
-	Log          string `json:"log"`
-	SnmpLog      string `json:"snmplog"`
-	SnmpPeriod   int    `json:"snmpperiod"`
-	Pprof        bool   `json:"pprof"`
 }
 
-func parseJSONConfig(config *Config, path string) error {
+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)
+	if err = json.NewDecoder(file).Decode(config); err != nil {
+		return err
+	}
+
+	return err
 }

server/main.go

@@ -2,14 +2,10 @@ package main
 
 import (
 	"crypto/sha1"
-	"encoding/csv"
-	"fmt"
 	"io"
 	"log"
 	"math/rand"
 	"net"
-	"net/http"
-	_ "net/http/pprof"
 	"os"
 	"time"
 
@@ -61,8 +57,6 @@ func handleMux(conn io.ReadWriteCloser, config *Config) {
 	// stream multiplex
 	smuxConfig := smux.DefaultConfig()
 	smuxConfig.MaxReceiveBuffer = config.SockBuf
-	smuxConfig.KeepAliveInterval = time.Duration(config.KeepAlive) * time.Second
-
 	mux, err := smux.Server(conn, smuxConfig)
 	if err != nil {
 		log.Println(err)
@@ -81,6 +75,12 @@ func handleMux(conn io.ReadWriteCloser, config *Config) {
 			log.Println(err)
 			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)
 	}
 }
@@ -93,10 +93,16 @@ 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 {
@@ -147,7 +153,7 @@ func main() {
 		cli.StringFlag{
 			Name:  "mode",
 			Value: "fast",
-			Usage: "profiles: fast3, fast2, fast, normal, manual",
+			Usage: "profiles: fast3, fast2, fast, normal",
 		},
 		cli.IntFlag{
 			Name:  "mtu",
@@ -165,12 +171,12 @@ func main() {
 			Usage: "set receive window size(num of packets)",
 		},
 		cli.IntFlag{
-			Name:  "datashard,ds",
+			Name:  "datashard",
 			Value: 10,
 			Usage: "set reed-solomon erasure coding - datashard",
 		},
 		cli.IntFlag{
-			Name:  "parityshard,ps",
+			Name:  "parityshard",
 			Value: 3,
 			Usage: "set reed-solomon erasure coding - parityshard",
 		},
@@ -195,7 +201,7 @@ func main() {
 		},
 		cli.IntFlag{
 			Name:   "interval",
-			Value:  50,
+			Value:  40,
 			Hidden: true,
 		},
 		cli.IntFlag{
@@ -218,25 +224,6 @@ func main() {
 			Value:  10, // nat keepalive interval in seconds
 			Hidden: true,
 		},
-		cli.StringFlag{
-			Name:  "snmplog",
-			Value: "",
-			Usage: "collect snmp to file, aware of timeformat in golang, like: ./snmp-20060102.log",
-		},
-		cli.IntFlag{
-			Name:  "snmpperiod",
-			Value: 60,
-			Usage: "snmp collect period, in seconds",
-		},
-		cli.BoolFlag{
-			Name:  "pprof",
-			Usage: "start profiling server on :6060",
-		},
-		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
@@ -264,30 +251,18 @@ func main() {
 		config.NoCongestion = c.Int("nc")
 		config.SockBuf = c.Int("sockbuf")
 		config.KeepAlive = c.Int("keepalive")
-		config.Log = c.String("log")
-		config.SnmpLog = c.String("snmplog")
-		config.SnmpPeriod = c.Int("snmpperiod")
-		config.Pprof = c.Bool("pprof")
 
 		if c.String("c") != "" {
 			//Now only support json config file
-			err := parseJSONConfig(&config, 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, 40, 2, 1
-		case "fast":
 			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":
@@ -339,9 +314,6 @@ func main() {
 		log.Println("dscp:", config.DSCP)
 		log.Println("sockbuf:", config.SockBuf)
 		log.Println("keepalive:", config.KeepAlive)
-		log.Println("snmplog:", config.SnmpLog)
-		log.Println("snmpperiod:", config.SnmpPeriod)
-		log.Println("pprof:", config.Pprof)
 
 		if err := lis.SetDSCP(config.DSCP); err != nil {
 			log.Println("SetDSCP:", err)
@@ -352,21 +324,15 @@ func main() {
 		if err := lis.SetWriteBuffer(config.SockBuf); err != nil {
 			log.Println("SetWriteBuffer:", err)
 		}
-
-		go snmpLogger(config.SnmpLog, config.SnmpPeriod)
-		if config.Pprof {
-			go http.ListenAndServe(":6060", nil)
-		}
-
 		for {
 			if conn, err := lis.AcceptKCP(); err == nil {
 				log.Println("remote address:", conn.RemoteAddr())
 				conn.SetStreamMode(true)
-				conn.SetWriteDelay(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)
@@ -380,34 +346,3 @@ func main() {
 	}
 	myApp.Run(os.Args)
 }
-
-func snmpLogger(path string, interval int) {
-	if path == "" || interval == 0 {
-		return
-	}
-	ticker := time.NewTicker(time.Duration(interval) * time.Second)
-	defer ticker.Stop()
-	for {
-		select {
-		case <-ticker.C:
-			f, err := os.OpenFile(time.Now().Format(path), os.O_RDWR|os.O_CREATE|os.O_APPEND, 0666)
-			if err != nil {
-				log.Println(err)
-				return
-			}
-			w := csv.NewWriter(f)
-			// write header in empty file
-			if stat, err := f.Stat(); err == nil && stat.Size() == 0 {
-				if err := w.Write(append([]string{"Unix"}, kcp.DefaultSnmp.Header()...)); err != nil {
-					log.Println(err)
-				}
-			}
-			if err := w.Write(append([]string{fmt.Sprint(time.Now().Unix())}, kcp.DefaultSnmp.ToSlice()...)); err != nil {
-				log.Println(err)
-			}
-			kcp.DefaultSnmp.Reset()
-			w.Flush()
-			f.Close()
-		}
-	}
-}

server/signal.go

@@ -18,7 +18,6 @@ func init() {
 func sigHandler() {
 	ch := make(chan os.Signal, 1)
 	signal.Notify(ch, syscall.SIGUSR1)
-	signal.Ignore(syscall.SIGPIPE)
 
 	for {
 		switch <-ch {