Introduction

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.

Features

1. Optimized for Real-Time Strategy Game.
2. Compatible with skywind3000's C version with optimizations.
3. Cache friendly and Memory optimized design in golang.
4. Compatible with net.Conn and net.Listener.
5. FEC(Forward Error Correction) Support with Reed-Solomon Codes
6. Packet level encryption support with AES, TEA, 3DES, Blowfish, Cast5, Salsa20, etc. in CFB mode.

Conventions

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, see kcptun for example.

Documentation

For complete documentation, see the associated Godoc.

Specification

Usage

Client: full demo

kcpconn, err := kcp.DialWithOptions("192.168.0.1:10000", nil, 10, 3)

Server: full demo

lis, err := kcp.ListenWithOptions(":10000", nil, 10, 3)

Performance

  型号名称：	MacBook Pro
  型号标识符：	MacBookPro12,1
  处理器名称：	Intel Core i5
  处理器速度：	2.7 GHz
  处理器数目：	1
  核总数：	2
  L2 缓存（每个核）：	256 KB
  L3 缓存：	3 MB
  内存：	8 GB

$ go test -run Speed
new client 127.0.0.1:61165
total recv: 16777216
time for 16MB rtt with encryption 570.41176ms
&{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}
PASS
ok  	github.com/xtaci/kcp-go	0.600s

Who is using this?

1. https://github.com/xtaci/kcptun
2. https://github.com/getlantern/lantern
3. https://github.com/smallnest/rpcx

Links

1. https://github.com/xtaci/libkcp -- FEC enhanced KCP session library for iOS/Android in C++
2. https://github.com/skywind3000/kcp -- A Fast and Reliable ARQ Protocol
3. https://github.com/klauspost/reedsolomon -- Reed-Solomon Erasure Coding in Go