90 lines
4.0 KiB
Markdown
90 lines
4.0 KiB
Markdown
<img src="kcp-go.png" alt="kcp-go" height="50px" />
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[![GoDoc][1]][2] [![Powered][9]][10] [![MIT licensed][11]][12] [![Build Status][3]][4] [![Go Report Card][5]][6] [![Coverage Statusd][7]][8]
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[1]: https://godoc.org/github.com/xtaci/kcp-go?status.svg
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[2]: https://godoc.org/github.com/xtaci/kcp-go
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[3]: https://travis-ci.org/xtaci/kcp-go.svg?branch=master
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[4]: https://travis-ci.org/xtaci/kcp-go
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[5]: https://goreportcard.com/badge/github.com/xtaci/kcp-go
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[6]: https://goreportcard.com/report/github.com/xtaci/kcp-go
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[7]: https://codecov.io/gh/xtaci/kcp-go/branch/master/graph/badge.svg
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[8]: https://codecov.io/gh/xtaci/kcp-go
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[9]: https://img.shields.io/badge/KCP-Powered-blue.svg
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[10]: https://github.com/skywind3000/kcp
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[11]: https://img.shields.io/badge/license-MIT-blue.svg
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[12]: LICENSE
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[](https://en.wikipedia.org/wiki/Claude_Shannon)
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## Introduction
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kcp-go is a full-featured ***Reliable-UDP*** library for golang. It provides ***reliable, ordered, and error-checked*** delivery of a stream of octets between applications running on hosts communicating over an IP network.
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## Features
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1. Optimized for ***Online Games, Audio/Video Streaming***.
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1. Compatible with [skywind3000's](https://github.com/skywind3000) C version with optimizations.
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1. ***Cache friendly*** and ***Memory optimized*** design in golang.
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1. Compatible with [net.Conn](https://golang.org/pkg/net/#Conn) and [net.Listener](https://golang.org/pkg/net/#Listener).
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1. [FEC(Forward Error Correction)](https://en.wikipedia.org/wiki/Forward_error_correction) Support with [Reed-Solomon Codes](https://en.wikipedia.org/wiki/Reed%E2%80%93Solomon_error_correction)
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1. Packet level encryption support with [AES](https://en.wikipedia.org/wiki/Advanced_Encryption_Standard), [TEA](https://en.wikipedia.org/wiki/Tiny_Encryption_Algorithm), [3DES](https://en.wikipedia.org/wiki/Triple_DES), [Blowfish](https://en.wikipedia.org/wiki/Blowfish_(cipher)), [Cast5](https://en.wikipedia.org/wiki/CAST-128), [Salsa20]( https://en.wikipedia.org/wiki/Salsa20), etc. in [CFB](https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation#Cipher_Feedback_.28CFB.29) mode.
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## Conventions
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Control messages like SYN/FIN/RST in TCP ***are not defined*** in KCP, you need some ***keepalive mechanims*** in the application-level. a real world example is to use some ***multiplexing*** protocol over session, such as [smux](https://github.com/xtaci/smux), see [kcptun](https://github.com/xtaci/kcptun) for example.
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## Documentation
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For complete documentation, see the associated [Godoc](https://godoc.org/github.com/xtaci/kcp-go).
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## Specification
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<img src="frame.png" alt="Frame Format" height="109px" />
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## Usage
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Client: [full demo](https://github.com/xtaci/kcptun/blob/master/client/main.go#L231)
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```go
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kcpconn, err := kcp.DialWithOptions("192.168.0.1:10000", nil, 10, 3)
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```
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Server: [full demo](https://github.com/xtaci/kcptun/blob/master/server/main.go#L235)
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```go
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lis, err := kcp.ListenWithOptions(":10000", nil, 10, 3)
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```
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## Performance
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```
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型号名称： MacBook Pro
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型号标识符： MacBookPro12,1
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处理器名称： Intel Core i5
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处理器速度： 2.7 GHz
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处理器数目： 1
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核总数： 2
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L2 缓存（每个核）： 256 KB
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L3 缓存： 3 MB
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内存： 8 GB
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```
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```
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$ go test -run Speed
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new client 127.0.0.1:61165
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total recv: 16777216
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time for 16MB rtt with encryption 570.41176ms
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&{BytesSent:33554432 BytesReceived:33554432 MaxConn:2 ActiveOpens:1 PassiveOpens:1 CurrEstab:1 InErrs:0 InCsumErrors:0 InSegs:42577 OutSegs:42641 OutBytes:48111336 RetransSegs:92 FastRetransSegs:92 LostSegs:0 RepeatSegs:0 FECRecovered:1 FECErrs:0 FECSegs:8514}
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PASS
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ok github.com/xtaci/kcp-go 0.600s
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```
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## Who is using this?
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1. https://github.com/xtaci/kcptun
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2. https://github.com/getlantern/lantern
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3. https://github.com/smallnest/rpcx
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## Links
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1. https://github.com/xtaci/libkcp -- FEC enhanced KCP session library for iOS/Android in C++
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2. https://github.com/skywind3000/kcp -- A Fast and Reliable ARQ Protocol
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3. https://github.com/klauspost/reedsolomon -- Reed-Solomon Erasure Coding in Go
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