Revert "passive tunnel termination"

This reverts commit bf1d0d6419.

.github/ISSUE_TEMPLATE

@@ -1,3 +1,15 @@
+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.
@@ -11,3 +23,5 @@ 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:
-    - 1.6
+    - 1.9
 before_install:
     - go get github.com/mattn/goveralls
     - go get golang.org/x/tools/cmd/cover

Dockerfile

@@ -1,8 +1,11 @@
-FROM golang:alpine
+FROM golang:alpine as builder
 MAINTAINER xtaci <daniel820313@gmail.com>
 RUN apk update && \
     apk upgrade && \
     apk add git
-RUN go get github.com/xtaci/kcptun/client && go get github.com/xtaci/kcptun/server
+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
+
+FROM alpine:3.6
+COPY --from=builder /go/bin /bin
 EXPOSE 29900/udp
 EXPOSE 12948

README.en.md

@@ -1,250 +0,0 @@
-# <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:
-Client, server, respectively, download the corresponding platform binary compression package, and extract, through the following command to start port forwarding.
-```
-Server: ./server_linux_amd64 -t "SERVER_IP:8388" -l ":4000" -mode fast2
-Client: ./client_darwin_amd64 -r "SERVER_IP:4000" -l ":8388" -mode fast2
-```
-The above command can establish 8388/tcp port forwarding (through 4000/udp port).
-
-
-### *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 - client(with SMUX)
-
-USAGE:
-   client_darwin_amd64 [global options] command [command options] [arguments...]
-
-VERSION:
-   20160922
-
-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") [$KCPTUN_KEY]
-   --crypt value                 aes, aes-128, aes-192, salsa20, blowfish, twofish, cast5, 3des, tea, xtea, xor, none (default: "aes")
-   --mode value                  profiles: fast3, fast2, fast, normal (default: "fast")
-   --conn value                  set num of UDP connections to server (default: 1)
-   --autoexpire value            set auto expiration time(in seconds) for a single UDP connection, 0 to disable (default: 0)
-   --mtu value                   set maximum transmission unit for UDP packets (default: 1350)
-   --sndwnd value                set send window size(num of packets) (default: 128)
-   --rcvwnd value                set receive window size(num of packets) (default: 1024)
-   --datashard value             set reed-solomon erasure coding - datashard (default: 10)
-   --parityshard value           set reed-solomon erasure coding - parityshard (default: 3)
-   --dscp value                  set DSCP(6bit) (default: 0)
-   --nocomp                      disable compression
-   --log value                   specify a log file to output, default goes to stderr
-   -c value                      config from json file, which will override the command from shell
-   --help, -h                    show help
-   --version, -v                 print the version
-
-$ ./server_darwin_amd64 -h
-NAME:
-   kcptun - server(with SMUX)
-
-USAGE:
-   server_darwin_amd64 [global options] command [command options] [arguments...]
-
-VERSION:
-   20160922
-
-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         set reed-solomon erasure coding - datashard (default: 10)
-   --parityshard value       set reed-solomon erasure coding - parityshard (default: 3)
-   --dscp value              set DSCP(6bit) (default: 0)
-   --nocomp                  disable compression
-   --log value               specify a log file to output, default goes to stderr
-   -c value                  config from json file, which will override the command from shell
-   --help, -h                show help
-   --version, -v             print the version
-```
-#### *Parameters by Layers* :lollipop:   
-
-<p align="left"><img src="layeredparams.png" alt="params" height="450px"/></p>
-
-### *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 m -parityshard n```
-
-### *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)          
-
-Best wishes to you all.
-
-### *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

@@ -1,9 +1,7 @@
-<p align="center"><img src="logo.png" alt="kcptun" height="60px" /></p>
-<p align="center"><em>也许是世界上最快的UDP传输工具</em></p>
+# <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]
 
-[![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
@@ -20,35 +18,77 @@
 [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
 
-<p align="center"><img src="kcptun.png" alt="kcptun" height="200px"/></p>
-<p align="center"><a href="https://github.com/xtaci/kcptun/releases/latest">立即安装</a></p>
-<p align="center"><em>支持macOS/Linux/Windows/FreeBSD/ARM/Raspberry Pi/OpenWrt</em></p>
-<p align="right"><a href="https://github.com/xtaci/kcptun/blob/master/README.en.md">ENG</a></p>
+<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.*
+
+> *KCP communication group: 364933586 (QQ group number), KCP integration, tuning, network transmission and related technical discussions.*
+
+### QuickStart
+
+Increase number of open files on your server, as:
+
+`ulimit -n 65535`, or write it in `~/.bashrc`.
+
+Download precompiled [Releases](https://github.com/xtaci/kcptun/releases).
+
+```
+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
+```
+
+All precompiled releases are genereated from `build-release.sh` script.
+
+### Performance
+
+<img src="fast.png" alt="fast.com" height="256px" />       
+
+### 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*
 
 -
 
-### 快速设定
+### Expert Tuning Guide
 
-客户端、服务器分别**下载**对应平台的二进制压缩包，并**解压**，通过下面的命令**启动**端口转发。
-```
-服务器: ./server_linux_amd64 -t "服务器IP地址:8388" -l ":4000" -mode fast2
-客户端: ./client_darwin_amd64 -r "服务器IP地址:4000" -l ":8388" -mode fast2
-```
-以上命令可以实现8388/tcp端口的转发（通过4000/udp端口）。
+#### Overview
 
-### 速度对比
+<p align="left"><img src="layeredparams.png" alt="params" height="450px"/></p>
 
-<img src="fast.png" alt="fast.com" height="256px" />       
-* 测速网站: https://fast.com
-* 接入速度: 100Mbps
-* WIFI: 5GHz TL-WDR3320
+#### Usage
 
-### 使用方法
-
-在Mac OS X El Capitan下的帮助输出，注意默认值: 
 ```
 $ ./client_darwin_amd64 -h
 NAME:
@@ -58,30 +98,32 @@ USAGE:
    client_darwin_amd64 [global options] command [command options] [arguments...]
 
 VERSION:
-   20161025
+   20170120
 
 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") [$KCPTUN_KEY]
-   --crypt value                 aes, aes-128, aes-192, salsa20, blowfish, twofish, cast5, 3des, tea, xtea, xor, none (default: "aes")
-   --mode value                  profiles: fast3, fast2, fast, normal (default: "fast")
-   --conn value                  set num of UDP connections to server (default: 1)
-   --autoexpire value            set auto expiration time(in seconds) for a single UDP connection, 0 to disable (default: 0)
-   --mtu value                   set maximum transmission unit for UDP packets (default: 1350)
-   --sndwnd value                set send window size(num of packets) (default: 128)
-   --rcvwnd value                set receive window size(num of packets) (default: 1024)
-   --datashard value             set reed-solomon erasure coding - datashard (default: 10)
-   --parityshard value           set reed-solomon erasure coding - parityshard (default: 3)
-   --dscp value                  set DSCP(6bit) (default: 0)
-   --nocomp                      disable compression
-   --log value                   specify a log file to output, default goes to stderr
-   -c value                      config from json file, which will override the command from shell
-   --help, -h                    show help
-   --version, -v                 print the version
+   --localaddr value, -l value      local listen address (default: ":12948")
+   --remoteaddr value, -r value     kcp server address (default: "vps:29900")
+   --key value                      pre-shared secret between client and server (default: "it's a secrect") [$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
 
 $ ./server_darwin_amd64 -h
 NAME:
@@ -91,91 +133,60 @@ USAGE:
    server_darwin_amd64 [global options] command [command options] [arguments...]
 
 VERSION:
-   20161025
+   20170120
 
 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") [$KCPTUN_KEY]
-   --crypt value             aes, aes-128, aes-192, salsa20, blowfish, twofish, cast5, 3des, tea, xtea, xor, none (default: "aes")
-   --mode value              profiles: fast3, fast2, fast, normal (default: "fast")
-   --mtu value               set maximum transmission unit for UDP packets (default: 1350)
-   --sndwnd value            set send window size(num of packets) (default: 1024)
-   --rcvwnd value            set receive window size(num of packets) (default: 1024)
-   --datashard value         set reed-solomon erasure coding - datashard (default: 10)
-   --parityshard value       set reed-solomon erasure coding - parityshard (default: 3)
-   --dscp value              set DSCP(6bit) (default: 0)
-   --nocomp                  disable compression
-   --log value               specify a log file to output, default goes to stderr
-   -c value                  config from json file, which will override the command from shell
-   --help, -h                show help
-   --version, -v             print the version
-```
-#### 分层参数图
-
-<p align="left"><img src="layeredparams.png" alt="params" height="450px"/></p>
-
-### 内置模式
-
-响应速度:     
-*fast3 > fast2 >* **[fast]** *> normal > default*        
-有效载荷比:     
-*default > normal >* **[fast]** *> fast2 > fast3*       
-中间mode参数比较均衡，总之就是越快，包重传越激进。       
-更高级的 **手动档** 需要理解KCP协议，并通过 **隐藏参数** 调整，例如:
-```
- -mode manual -nodelay 1 -resend 2 -nc 1 -interval 20
+   --listen value, -l value         kcp server listen address (default: ":29900")
+   --target value, -t value         target server address (default: "127.0.0.1:12948")
+   --key value                      pre-shared secret between client and server (default: "it's a secrect") [$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
 ```
 
-* 搭配1. fast + FEC(5,5)
-* 搭配2. fast2 + FEC(10,3)
-* 搭配3. fast2 + FEC(0,0)
+#### Forward Error Correction
 
-默认profile参考: https://github.com/xtaci/kcptun/blob/master/client/main.go#L248
+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.
 
-### 前向纠错
-
-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**。
+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)
 
-通过参数```-datashard n -parityshard m``` 在两端同时设定。
+Setting parameters of RS-Code with ```-datashard m -parityshard n``` on **BOTH** KCP Client & KCP Server **MUST** be **IDENTICAL**.
 
-数据包发送顺序严格遵循: n个datashard紧接m个parityshard，重复。
+#### DSCP
 
-注意：为了发挥FEC最佳效果，设置 parityshard/(parity+datashard) > packet loss，比如5/(5+5) > 30%
+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.
 
-### 窗口调整
+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.
 
-**两端参数必须一致的有**:
+setting each side with ```-dscp value```, Here are some [Commonly used DSCP values](https://en.wikipedia.org/wiki/Differentiated_services#Commonly_used_DSCP_values).
 
-* datashard --前向纠错
-* parityshard --前向纠错
-* nocomp --压缩
-* key --密钥
-* crypt --加密算法
+#### Security
 
-其余为两边可独立设定的参数
+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 .
 
-**简易窗口自我调优方法**：
+`-crypt` and `-key` must be the same on both KCP Client & KCP Server.
 
-> 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。
+NOTICE: ```-crypt xor``` is also insecure, do not use this unless you know what you are doing.
 
-**注意：产生大量重传时，一定是窗口偏大了**
-
-### 安全
-
-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，并修改密码。
-
-密码可以通过`-key`指定，也可以通过环境变量`KCPTUN_KEY`指定。
-
-注意: ```-crypt xor``` 也是不安全的，除非你知道你在做什么。 
-
-附加密速度Benchmark：
+Benchmarks for crypto algorithms supported by kcptun:
 
 ```
 BenchmarkAES128-4      	  200000	     11182 ns/op
@@ -192,22 +203,16 @@ BenchmarkXTEA-4        	   20000	     77417 ns/op
 BenchmarkSalsa20-4     	  300000	      4998 ns/op
 ```
 
-### 内存控制
-
-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
 
 
-### DSCP
+#### Memory Control
 
-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。 
+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
 
-通过 ```-dscp ``` 参数指定dscp值，两端可分别设定。
+#### Compression
 
-注意：设置dscp不一定会更好，需要尝试。
-
-### Snappy数据流压缩
+kcptun has builtin snappy algorithms for compressing streams:
 
 > Snappy is a compression/decompression library. It does not aim for maximum
 > compression, or compatibility with any other compression library; instead,
@@ -218,133 +223,82 @@ DSCP差分服务代码点（Differentiated Services Code Point），IETF于1998
 
 > 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。
+Compression may save bandwidth for **PLAINTEXT** data, such as HTTP data.
 
-### 流量控制
+Compression is enabled by default, you can disable it by setting ```-nocomp``` on **BOTH** KCP Client & KCP Server **MUST** be **IDENTICAL**.
 
-**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。
-
-### SNMP
+#### SNMP
 
 ```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
+    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
 }
 ```
 
-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。    
+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.
 
-#### 带宽计算公式
+### Manual Control
 
-```
-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：     
+https://github.com/skywind3000/kcp/blob/master/README.en.md#protocol-configuration
 
-		network_cap = rcvwnd*avgsize
+`-mode manual -nodelay 1 -interval 20 -resend 2 -nc 1`
 
-数据流向你，这个值再除以ping值(rtt)，等于最大带宽使用量。
+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.
 
-		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）
+### Identical Parmeters
 
-前向纠错是最大带宽量的一个固定比例增加：
+The parameters below **MUST** be **IDENTICAL** on **BOTH** side:
 
-		max_bandwidth_fec = max_bandwidth*(datashard+parityshard)/datashard
+1. -key
+1. -crypt
+1. -nocomp
+1. -datashard
+1. -parityshard
 
-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
-```
-
-### 故障排除
-
-> 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
-
-**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
-
-![donate](donate.png)          
-
-### 特别鸣谢
-
-> 郑H立, 南东风, Li, 七七, 凌君, 昶，LesMiserables, KyOn, 噼里啪啦, 继斌, 小苍辛苦, **Ken**, 
-> 乔槁, 佳晨, 猪肉佬, lcx, 昊文, 冰峰, 凡, alex, **海豹叔叔**, 奥姐, 张冰, 司成, 
-> 武子, **慎**，Alex43211，**Coxxs**，荣，NeroNg，吴骁，定一，我不是林J
-
-好人一生平安!
-
-### 相关软件
-
-1. https://github.com/bettermanbao/openwrt-kcptun
-2. https://github.com/EasyPi/openwrt-kcptun
-3. https://github.com/kuoruan/luci-app-kcptun
-4. https://github.com/dfdragon/kcptun_gclient
-
-### 参考资料
+### References
 
 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
-14. https://en.wikipedia.org/wiki/Noisy-channel_coding_theorem -- Noisy channel coding theorem
+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 Ethereum(ETH)
+
+Address: 0x2e4b43ab3d0983da282592571eef61ae5e60f726 , Or scan here:
+
+<img src="0x2e4b43ab3d0983da282592571eef61ae5e60f726.png" alt="kcptun" height="100px" /> 

build-release.sh

@@ -1,8 +1,13 @@
 #!/bin/bash
-MD5='md5sum'
-unamestr=`uname`
-if [[ "$unamestr" == 'Darwin' ]]; then
-	MD5='md5'
+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"
 fi
 
 UPX=false
@@ -27,7 +32,7 @@ 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}
-		$MD5 kcptun-${os}-${arch}-$VERSION.tar.gz
+		$sum kcptun-${os}-${arch}-$VERSION.tar.gz
 	done
 done
 
@@ -39,4 +44,16 @@ 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*
-$MD5 kcptun-linux-arm-$VERSION.tar.gz
+$sum kcptun-linux-arm-$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

client/config.go

@@ -14,6 +14,7 @@ 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"`
@@ -29,6 +30,9 @@ type Config struct {
 	SockBuf      int    `json:"sockbuf"`
 	KeepAlive    int    `json:"keepalive"`
 	Log          string `json:"log"`
+	SnmpLog      string `json:"snmplog"`
+	SnmpPeriod   int    `json:"snmpperiod"`
+	Quiet        bool   `json:"quiet"`
 }
 
 func parseJSONConfig(config *Config, path string) error {

client/main.go

@@ -2,6 +2,8 @@ package main
 
 import (
 	"crypto/sha1"
+	"encoding/csv"
+	"fmt"
 	"io"
 	"log"
 	"math/rand"
@@ -11,7 +13,7 @@ import (
 
 	"golang.org/x/crypto/pbkdf2"
 
-	"github.com/klauspost/compress/snappy"
+	"github.com/golang/snappy"
 	"github.com/pkg/errors"
 	"github.com/urfave/cli"
 	kcp "github.com/xtaci/kcp-go"
@@ -53,10 +55,17 @@ func newCompStream(conn net.Conn) *compStream {
 	return c
 }
 
-func handleClient(p1, p2 io.ReadWriteCloser) {
-	log.Println("stream opened")
-	defer log.Println("stream closed")
+func handleClient(sess *smux.Session, p1 io.ReadWriteCloser, quiet bool) {
+	if !quiet {
+		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
@@ -110,12 +119,12 @@ func main() {
 		cli.StringFlag{
 			Name:  "crypt",
 			Value: "aes",
-			Usage: "aes, aes-128, aes-192, salsa20, blowfish, twofish, cast5, 3des, tea, xtea, xor, none",
+			Usage: "aes, aes-128, aes-192, salsa20, blowfish, twofish, cast5, 3des, tea, xtea, xor, sm4, none",
 		},
 		cli.StringFlag{
 			Name:  "mode",
 			Value: "fast",
-			Usage: "profiles: fast3, fast2, fast, normal",
+			Usage: "profiles: fast3, fast2, fast, normal, manual",
 		},
 		cli.IntFlag{
 			Name:  "conn",
@@ -127,6 +136,11 @@ 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,
@@ -139,16 +153,16 @@ func main() {
 		},
 		cli.IntFlag{
 			Name:  "rcvwnd",
-			Value: 1024,
+			Value: 512,
 			Usage: "set receive window size(num of packets)",
 		},
 		cli.IntFlag{
-			Name:  "datashard",
+			Name:  "datashard,ds",
 			Value: 10,
 			Usage: "set reed-solomon erasure coding - datashard",
 		},
 		cli.IntFlag{
-			Name:  "parityshard",
+			Name:  "parityshard,ps",
 			Value: 3,
 			Usage: "set reed-solomon erasure coding - parityshard",
 		},
@@ -173,7 +187,7 @@ func main() {
 		},
 		cli.IntFlag{
 			Name:   "interval",
-			Value:  40,
+			Value:  50,
 			Hidden: true,
 		},
 		cli.IntFlag{
@@ -196,11 +210,25 @@ 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.BoolFlag{
+			Name:  "quiet",
+			Usage: "to suppress the 'stream open/close' messages",
+		},
 		cli.StringFlag{
 			Name:  "c",
 			Value: "", // when the value is not empty, the config path must exists
@@ -216,6 +244,7 @@ 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")
@@ -231,6 +260,9 @@ func main() {
 		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.Quiet = c.Bool("quiet")
 
 		if c.String("c") != "" {
 			err := parseJSONConfig(&config, c.String("c"))
@@ -247,9 +279,9 @@ func main() {
 
 		switch config.Mode {
 		case "normal":
-			config.NoDelay, config.Interval, config.Resend, config.NoCongestion = 0, 30, 2, 1
+			config.NoDelay, config.Interval, config.Resend, config.NoCongestion = 0, 40, 2, 1
 		case "fast":
-			config.NoDelay, config.Interval, config.Resend, config.NoCongestion = 0, 20, 2, 1
+			config.NoDelay, config.Interval, config.Resend, config.NoCongestion = 0, 30, 2, 1
 		case "fast2":
 			config.NoDelay, config.Interval, config.Resend, config.NoCongestion = 1, 20, 2, 1
 		case "fast3":
@@ -265,6 +297,8 @@ func main() {
 		pass := pbkdf2.Key([]byte(config.Key), []byte(SALT), 4096, 32, sha1.New)
 		var block kcp.BlockCrypt
 		switch config.Crypt {
+		case "sm4":
+			block, _ = kcp.NewSM4BlockCrypt(pass[:16])
 		case "tea":
 			block, _ = kcp.NewTEABlockCrypt(pass[:16])
 		case "xor":
@@ -306,9 +340,14 @@ 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)
+		log.Println("quiet:", config.Quiet)
 
 		smuxConfig := smux.DefaultConfig()
 		smuxConfig.MaxReceiveBuffer = config.SockBuf
+		smuxConfig.KeepAliveInterval = time.Duration(config.KeepAlive) * time.Second
 
 		createConn := func() (*smux.Session, error) {
 			kcpconn, err := kcp.DialWithOptions(config.RemoteAddr, block, config.DataShard, config.ParityShard)
@@ -316,11 +355,11 @@ func main() {
 				return nil, errors.Wrap(err, "createConn()")
 			}
 			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)
@@ -342,6 +381,7 @@ func main() {
 			if err != nil {
 				return nil, errors.Wrap(err, "createConn()")
 			}
+			log.Println("connection:", kcpconn.LocalAddr(), "->", kcpconn.RemoteAddr())
 			return session, nil
 		}
 
@@ -351,6 +391,7 @@ func main() {
 				if session, err := createConn(); err == nil {
 					return session
 				} else {
+					log.Println("re-connecting:", err)
 					time.Sleep(time.Second)
 				}
 			}
@@ -363,43 +404,30 @@ func main() {
 		}, numconn)
 
 		for k := range muxes {
-			sess, err := createConn()
-			checkError(err)
-			muxes[k].session = sess
+			muxes[k].session = waitConn()
 			muxes[k].ttl = time.Now().Add(time.Duration(config.AutoExpire) * time.Second)
 		}
 
 		chScavenger := make(chan *smux.Session, 128)
-		go scavenger(chScavenger)
+		go scavenger(chScavenger, config.ScavengeTTL)
+		go snmpLogger(config.SnmpLog, config.SnmpPeriod)
 		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)
+			if err != nil {
+				log.Fatalln(err)
 			}
 			checkError(err)
 			idx := rr % numconn
 
-		OPEN_P2:
-			// do auto expiration
-			if config.AutoExpire > 0 && time.Now().After(muxes[idx].ttl) {
+			// do auto expiration && reconnection
+			if muxes[idx].session.IsClosed() || (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)
+			go handleClient(muxes[idx].session, p1, config.Quiet)
 			rr++
 		}
 	}
@@ -408,27 +436,27 @@ func main() {
 
 type scavengeSession struct {
 	session *smux.Session
-	ttl     time.Time
+	ts      time.Time
 }
 
-const (
-	maxScavengeTTL = 10 * time.Minute
-)
-
-func scavenger(ch chan *smux.Session) {
-	ticker := time.NewTicker(30 * time.Second)
+func scavenger(ch chan *smux.Session, ttl int) {
+	ticker := time.NewTicker(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() || time.Since(s.ttl) > maxScavengeTTL {
-					log.Println("session scavenged")
+				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")
 					s.session.Close()
 				} else {
 					newList = append(newList, sessionList[k])
@@ -438,3 +466,34 @@ func scavenger(ch chan *smux.Session) {
 		}
 	}
 }
+
+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

@@ -18,6 +18,7 @@ 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

@@ -27,6 +27,10 @@ type Config struct {
 	SockBuf      int    `json:"sockbuf"`
 	KeepAlive    int    `json:"keepalive"`
 	Log          string `json:"log"`
+	SnmpLog      string `json:"snmplog"`
+	SnmpPeriod   int    `json:"snmpperiod"`
+	Pprof        bool   `json:"pprof"`
+	Quiet        bool   `json:"quiet"`
 }
 
 func parseJSONConfig(config *Config, path string) error {

server/main.go

@@ -2,16 +2,20 @@ package main
 
 import (
 	"crypto/sha1"
+	"encoding/csv"
+	"fmt"
 	"io"
 	"log"
 	"math/rand"
 	"net"
+	"net/http"
+	_ "net/http/pprof"
 	"os"
 	"time"
 
 	"golang.org/x/crypto/pbkdf2"
 
-	"github.com/klauspost/compress/snappy"
+	"github.com/golang/snappy"
 	"github.com/urfave/cli"
 	kcp "github.com/xtaci/kcp-go"
 	"github.com/xtaci/smux"
@@ -57,6 +61,8 @@ 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)
@@ -75,19 +81,15 @@ 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)
+		go handleClient(p1, p2, config.Quiet)
 	}
 }
 
-func handleClient(p1, p2 io.ReadWriteCloser) {
-	log.Println("stream opened")
-	defer log.Println("stream closed")
+func handleClient(p1, p2 io.ReadWriteCloser, quiet bool) {
+	if !quiet {
+		log.Println("stream opened")
+		defer log.Println("stream closed")
+	}
 	defer p1.Close()
 	defer p2.Close()
 
@@ -142,12 +144,12 @@ func main() {
 		cli.StringFlag{
 			Name:  "crypt",
 			Value: "aes",
-			Usage: "aes, aes-128, aes-192, salsa20, blowfish, twofish, cast5, 3des, tea, xtea, xor, none",
+			Usage: "aes, aes-128, aes-192, salsa20, blowfish, twofish, cast5, 3des, tea, xtea, xor, sm4, none",
 		},
 		cli.StringFlag{
 			Name:  "mode",
 			Value: "fast",
-			Usage: "profiles: fast3, fast2, fast, normal",
+			Usage: "profiles: fast3, fast2, fast, normal, manual",
 		},
 		cli.IntFlag{
 			Name:  "mtu",
@@ -165,12 +167,12 @@ func main() {
 			Usage: "set receive window size(num of packets)",
 		},
 		cli.IntFlag{
-			Name:  "datashard",
+			Name:  "datashard,ds",
 			Value: 10,
 			Usage: "set reed-solomon erasure coding - datashard",
 		},
 		cli.IntFlag{
-			Name:  "parityshard",
+			Name:  "parityshard,ps",
 			Value: 3,
 			Usage: "set reed-solomon erasure coding - parityshard",
 		},
@@ -195,7 +197,7 @@ func main() {
 		},
 		cli.IntFlag{
 			Name:   "interval",
-			Value:  40,
+			Value:  50,
 			Hidden: true,
 		},
 		cli.IntFlag{
@@ -218,11 +220,29 @@ 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.BoolFlag{
+			Name:  "quiet",
+			Usage: "to suppress the 'stream open/close' messages",
+		},
 		cli.StringFlag{
 			Name:  "c",
 			Value: "", // when the value is not empty, the config path must exists
@@ -251,6 +271,10 @@ func main() {
 		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")
+		config.Quiet = c.Bool("quiet")
 
 		if c.String("c") != "" {
 			//Now only support json config file
@@ -268,9 +292,9 @@ func main() {
 
 		switch config.Mode {
 		case "normal":
-			config.NoDelay, config.Interval, config.Resend, config.NoCongestion = 0, 30, 2, 1
+			config.NoDelay, config.Interval, config.Resend, config.NoCongestion = 0, 40, 2, 1
 		case "fast":
-			config.NoDelay, config.Interval, config.Resend, config.NoCongestion = 0, 20, 2, 1
+			config.NoDelay, config.Interval, config.Resend, config.NoCongestion = 0, 30, 2, 1
 		case "fast2":
 			config.NoDelay, config.Interval, config.Resend, config.NoCongestion = 1, 20, 2, 1
 		case "fast3":
@@ -281,6 +305,8 @@ func main() {
 		pass := pbkdf2.Key([]byte(config.Key), []byte(SALT), 4096, 32, sha1.New)
 		var block kcp.BlockCrypt
 		switch config.Crypt {
+		case "sm4":
+			block, _ = kcp.NewSM4BlockCrypt(pass[:16])
 		case "tea":
 			block, _ = kcp.NewTEABlockCrypt(pass[:16])
 		case "xor":
@@ -322,6 +348,10 @@ 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)
+		log.Println("quiet:", config.Quiet)
 
 		if err := lis.SetDSCP(config.DSCP); err != nil {
 			log.Println("SetDSCP:", err)
@@ -332,15 +362,21 @@ 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)
@@ -354,3 +390,34 @@ 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

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