kcp

package module
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 Go to latest Published: Aug 14, 2016 License: MIT Imports: 20 Imported by: 0

README

kcp-go ♓

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A full-featured reliable UDP communication library.
Claude_Shannon

Features ⚡

  1. Optimized for Real-Time Strategy Game.
  2. Compatible with skywind3000's C version with modifications.
  3. Cache friendly and Memory optimized design in golang.
  4. A session manager has been provided, 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.

Conventions ⚡

  1. Packet delivery via UDP.
  2. The conversation id conv uint32 in session manager should be a random number initiated by client.
  3. KCP doesn't define session control messages like SYN/FIN/RST in TCP, a real world example is to use some multiplexing protocol over session, such as yamux, see kcptun for example.

Examples ⚡

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
  1. https://github.com/xtaci/libkcp -- Official client library for iOS/Android(C++11)
  2. https://github.com/skywind3000/kcp -- A Fast and Reliable ARQ Protocol
  3. https://github.com/klauspost/reedsolomon -- Reed-Solomon Erasure Coding in Go

Donation 💵

donate

All donations on this project will be used to support the development of gonet/2.

Documentation

Overview

Package kcp - A Fast and Reliable ARQ Protocol

Index

Constants

View Source 
const (
	IKCP_RTO_NDL     = 30  // no delay min rto
	IKCP_RTO_MIN     = 100 // normal min rto
	IKCP_RTO_DEF     = 200
	IKCP_RTO_MAX     = 60000
	IKCP_CMD_PUSH    = 81 // cmd: push data
	IKCP_CMD_ACK     = 82 // cmd: ack
	IKCP_CMD_WASK    = 83 // cmd: window probe (ask)
	IKCP_CMD_WINS    = 84 // cmd: window size (tell)
	IKCP_ASK_SEND    = 1  // need to send IKCP_CMD_WASK
	IKCP_ASK_TELL    = 2  // need to send IKCP_CMD_WINS
	IKCP_WND_SND     = 32
	IKCP_WND_RCV     = 32
	IKCP_MTU_DEF     = 1400
	IKCP_ACK_FAST    = 3
	IKCP_INTERVAL    = 100
	IKCP_OVERHEAD    = 24
	IKCP_DEADLINK    = 20
	IKCP_THRESH_INIT = 2
	IKCP_THRESH_MIN  = 2
	IKCP_PROBE_INIT  = 7000   // 7 secs to probe window size
	IKCP_PROBE_LIMIT = 120000 // up to 120 secs to probe window
)

Variables

This section is empty.

Functions

This section is empty.

Types

type AESBlockCrypt 

type AESBlockCrypt struct {
	// contains filtered or unexported fields
}

AESBlockCrypt implements BlockCrypt with AES

func (*AESBlockCrypt) Decrypt 

func (c *AESBlockCrypt) Decrypt(dst, src []byte)

Decrypt implements Decrypt interface

func (*AESBlockCrypt) Encrypt 

func (c *AESBlockCrypt) Encrypt(dst, src []byte)

Encrypt implements Encrypt interface

type BlockCrypt 

type BlockCrypt interface {
	// Encrypt encrypts the whole block in src into dst.
	// Dst and src may point at the same memory.
	Encrypt(dst, src []byte)

	// Decrypt decrypts the whole block in src into dst.
	// Dst and src may point at the same memory.
	Decrypt(dst, src []byte)
}

BlockCrypt defines encryption/decryption methods for a given byte slice

func NewAESBlockCrypt 

func NewAESBlockCrypt(key []byte) (BlockCrypt, error)

NewAESBlockCrypt initates AES BlockCrypt by the given key

func NewNoneBlockCrypt 

func NewNoneBlockCrypt(key []byte) (BlockCrypt, error)

NewNoneBlockCrypt initate NoneBlockCrypt by the given key

func NewSimpleXORBlockCrypt 

func NewSimpleXORBlockCrypt(key []byte) (BlockCrypt, error)

NewSimpleXORBlockCrypt initate SimpleXORBlockCrypt by the given key

func NewTEABlockCrypt 

func NewTEABlockCrypt(key []byte) (BlockCrypt, error)

NewTEABlockCrypt initate TEA BlockCrypt by the given key

type FEC 

type FEC struct {
	// contains filtered or unexported fields
}

FEC defines forward error correction for packets

type KCP 

type KCP struct {
	// contains filtered or unexported fields
}

KCP defines a single KCP connection

func NewKCP 

func NewKCP(conv uint32, output Output) *KCP

NewKCP create a new kcp control object, 'conv' must equal in two endpoint from the same connection.

func (*KCP) Check 

func (kcp *KCP) Check(current uint32) uint32

Check determines when should you invoke ikcp_update: returns when you should invoke ikcp_update in millisec, if there is no ikcp_input/_send calling. you can call ikcp_update in that time, instead of call update repeatly. Important to reduce unnacessary ikcp_update invoking. use it to schedule ikcp_update (eg. implementing an epoll-like mechanism, or optimize ikcp_update when handling massive kcp connections)

func (*KCP) Input 

func (kcp *KCP) Input(data []byte, update_ack bool) int

Input when you received a low level packet (eg. UDP packet), call it

func (*KCP) NoDelay 

func (kcp *KCP) NoDelay(nodelay, interval, resend, nc int) int

NoDelay options fastest: ikcp_nodelay(kcp, 1, 20, 2, 1) nodelay: 0:disable(default), 1:enable interval: internal update timer interval in millisec, default is 100ms resend: 0:disable fast resend(default), 1:enable fast resend nc: 0:normal congestion control(default), 1:disable congestion control

func (*KCP) PeekSize 

func (kcp *KCP) PeekSize() (length int)

PeekSize checks the size of next message in the recv queue

func (*KCP) Recv 

func (kcp *KCP) Recv(buffer []byte) (n int)

Recv is user/upper level recv: returns size, returns below zero for EAGAIN

func (*KCP) Send 

func (kcp *KCP) Send(buffer []byte) int

Send is user/upper level send, returns below zero for error

func (*KCP) SetMtu 

func (kcp *KCP) SetMtu(mtu int) int

SetMtu changes MTU size, default is 1400

func (*KCP) Update 

func (kcp *KCP) Update(current uint32)

Update updates state (call it repeatedly, every 10ms-100ms), or you can ask ikcp_check when to call it again (without ikcp_input/_send calling). 'current' - current timestamp in millisec.

func (*KCP) WaitSnd 

func (kcp *KCP) WaitSnd() int

WaitSnd gets how many packet is waiting to be sent

func (*KCP) WndSize 

func (kcp *KCP) WndSize(sndwnd, rcvwnd int) int

WndSize sets maximum window size: sndwnd=32, rcvwnd=32 by default

type Listener 

type Listener struct {
	// contains filtered or unexported fields
}

Listener defines a server listening for connections

func Listen 

func Listen(laddr string) (*Listener, error)

Listen listens for incoming KCP packets addressed to the local address laddr on the network "udp",

func ListenWithOptions 

func ListenWithOptions(laddr string, block BlockCrypt, dataShards, parityShards int) (*Listener, error)

ListenWithOptions listens for incoming KCP packets addressed to the local address laddr on the network "udp" with packet encryption, dataShards, parityShards defines Reed-Solomon Erasure Coding parameters

func (*Listener) Accept 

func (l *Listener) Accept() (*UDPSession, error)

Accept implements the Accept method in the Listener interface; it waits for the next call and returns a generic Conn.

func (*Listener) Addr 

func (l *Listener) Addr() net.Addr

Addr returns the listener's network address, The Addr returned is shared by all invocations of Addr, so do not modify it.

func (*Listener) Close 

func (l *Listener) Close() error

Close stops listening on the UDP address. Already Accepted connections are not closed.

func (*Listener) SetDSCP 

func (l *Listener) SetDSCP(dscp int) error

SetDSCP sets the 6bit DSCP field of IP header

func (*Listener) SetReadBuffer 

func (l *Listener) SetReadBuffer(bytes int) error

SetReadBuffer sets the socket read buffer for the Listener

func (*Listener) SetWriteBuffer 

func (l *Listener) SetWriteBuffer(bytes int) error

SetWriteBuffer sets the socket write buffer for the Listener

type NoneBlockCrypt 

type NoneBlockCrypt struct {
	// contains filtered or unexported fields
}

NoneBlockCrypt simple returns the plaintext

func (*NoneBlockCrypt) Decrypt 

func (c *NoneBlockCrypt) Decrypt(dst, src []byte)

Decrypt implements Decrypt interface

func (*NoneBlockCrypt) Encrypt 

func (c *NoneBlockCrypt) Encrypt(dst, src []byte)

Encrypt implements Encrypt interface

type Output 

type Output func(buf []byte, size int)

Output is a closure which captures conn and calls conn.Write

type Segment 

type Segment struct {
	// contains filtered or unexported fields
}

Segment defines a KCP segment

func NewSegment 

func NewSegment(size int) *Segment

NewSegment creates a KCP segment

type SimpleXORBlockCrypt 

type SimpleXORBlockCrypt struct {
	// contains filtered or unexported fields
}

SimpleXORBlockCrypt implements BlockCrypt with simple xor to a table

func (*SimpleXORBlockCrypt) Decrypt 

func (c *SimpleXORBlockCrypt) Decrypt(dst, src []byte)

Decrypt implements Decrypt interface

func (*SimpleXORBlockCrypt) Encrypt 

func (c *SimpleXORBlockCrypt) Encrypt(dst, src []byte)

Encrypt implements Encrypt interface

type Snmp 

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
}

Snmp defines network statistics indicator 

var DefaultSnmp *Snmp

DefaultSnmp is the global KCP connection statistics collector

func (*Snmp) Copy 

func (s *Snmp) Copy() *Snmp

Copy make a copy of current snmp snapshot

type TEABlockCrypt 

type TEABlockCrypt struct {
	// contains filtered or unexported fields
}

TEABlockCrypt implements BlockCrypt with TEA

func (*TEABlockCrypt) Decrypt 

func (c *TEABlockCrypt) Decrypt(dst, src []byte)

Decrypt implements Decrypt interface

func (*TEABlockCrypt) Encrypt 

func (c *TEABlockCrypt) Encrypt(dst, src []byte)

Encrypt implements Encrypt interface

type UDPSession 

type UDPSession struct {
	// contains filtered or unexported fields
}

UDPSession defines a KCP session implemented by UDP

func Dial 

func Dial(raddr string) (*UDPSession, error)

Dial connects to the remote address "raddr" on the network "udp"

func DialWithOptions 

func DialWithOptions(raddr string, block BlockCrypt, dataShards, parityShards int) (*UDPSession, error)

DialWithOptions connects to the remote address "raddr" on the network "udp" with packet encryption

func (*UDPSession) Close 

func (s *UDPSession) Close() error

Close closes the connection.

func (*UDPSession) GetConv 

func (s *UDPSession) GetConv() uint32

GetConv gets conversation id of a session

func (*UDPSession) LocalAddr 

func (s *UDPSession) LocalAddr() net.Addr

LocalAddr returns the local network address. The Addr returned is shared by all invocations of LocalAddr, so do not modify it.

func (*UDPSession) Read 

func (s *UDPSession) Read(b []byte) (n int, err error)

Read implements the Conn Read method.

func (*UDPSession) RemoteAddr 

func (s *UDPSession) RemoteAddr() net.Addr

RemoteAddr returns the remote network address. The Addr returned is shared by all invocations of RemoteAddr, so do not modify it.

func (*UDPSession) SetACKNoDelay 

func (s *UDPSession) SetACKNoDelay(nodelay bool)

SetACKNoDelay changes ack flush option, set true to flush ack immediately,

func (*UDPSession) SetDSCP 

func (s *UDPSession) SetDSCP(dscp int) error

SetDSCP sets the 6bit DSCP field of IP header, no effect if it's accepted from Listener

func (*UDPSession) SetDeadline 

func (s *UDPSession) SetDeadline(t time.Time) error

SetDeadline sets the deadline associated with the listener. A zero time value disables the deadline.

func (*UDPSession) SetKeepAlive 

func (s *UDPSession) SetKeepAlive(interval int)

SetKeepAlive changes per-connection NAT keepalive interval; 0 to disable, default to 10s

func (*UDPSession) SetMtu 

func (s *UDPSession) SetMtu(mtu int)

SetMtu sets the maximum transmission unit

func (*UDPSession) SetNoDelay 

func (s *UDPSession) SetNoDelay(nodelay, interval, resend, nc int)

SetNoDelay calls nodelay() of kcp

func (*UDPSession) SetReadBuffer 

func (s *UDPSession) SetReadBuffer(bytes int) error

SetReadBuffer sets the socket read buffer, no effect if it's accepted from Listener

func (*UDPSession) SetReadDeadline 

func (s *UDPSession) SetReadDeadline(t time.Time) error

SetReadDeadline implements the Conn SetReadDeadline method.

func (*UDPSession) SetStreamMode 

func (s *UDPSession) SetStreamMode(enable bool)

SetStreamMode toggles the stream mode on/off

func (*UDPSession) SetWindowSize 

func (s *UDPSession) SetWindowSize(sndwnd, rcvwnd int)

SetWindowSize set maximum window size

func (*UDPSession) SetWriteBuffer 

func (s *UDPSession) SetWriteBuffer(bytes int) error

SetWriteBuffer sets the socket write buffer, no effect if it's accepted from Listener

func (*UDPSession) SetWriteDeadline 

func (s *UDPSession) SetWriteDeadline(t time.Time) error

SetWriteDeadline implements the Conn SetWriteDeadline method.

func (*UDPSession) Write 

func (s *UDPSession) Write(b []byte) (n int, err error)

Write implements the Conn Write method.

Source Files

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