kcp

package module
v5.6.3 Latest Latest
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 Go to latest Published: Dec 12, 2022 License: MIT Imports: 32 Imported by: 0

README

关于本分支

详见：KCP-GO的重传机制以及带宽利用率的提升

基于此分支的KCPTUN：https://github.com/yzslab/kcptun

原README：点击此处查阅

Documentation

Overview

Package kcp-go is a Reliable-UDP library for golang.

This library intents to provide a smooth, resilient, ordered, error-checked and anonymous delivery of streams over UDP packets.

The interfaces of this package aims to be compatible with net.Conn in standard library, but offers powerful features for advanced users.

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
	IKCP_SN_OFFSET   = 12
)

Variables

This section is empty.

Functions

func Dial 

func Dial(raddr string) (net.Conn, error)

Dial connects to the remote address "raddr" on the network "udp" without encryption and FEC

func Listen 

func Listen(laddr string) (net.Listener, error)

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

Types

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. Notes on implementing: the data to be encrypted contains a builtin nonce at the first 16 bytes

func NewAESBlockCrypt 

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

NewAESBlockCrypt https://en.wikipedia.org/wiki/Advanced_Encryption_Standard

func NewBlowfishBlockCrypt 

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

NewBlowfishBlockCrypt https://en.wikipedia.org/wiki/Blowfish_(cipher)

func NewCast5BlockCrypt 

func NewCast5BlockCrypt(key []byte) (BlockCrypt, error)

NewCast5BlockCrypt https://en.wikipedia.org/wiki/CAST-128

func NewNoneBlockCrypt 

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

NewNoneBlockCrypt does nothing but copying

func NewSM4BlockCrypt 

func NewSM4BlockCrypt(key []byte) (BlockCrypt, error)

NewSM4BlockCrypt https://github.com/tjfoc/gmsm/tree/master/sm4

func NewSalsa20BlockCrypt 

func NewSalsa20BlockCrypt(key []byte) (BlockCrypt, error)

NewSalsa20BlockCrypt https://en.wikipedia.org/wiki/Salsa20

func NewSimpleXORBlockCrypt 

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

NewSimpleXORBlockCrypt simple xor with key expanding

func NewTEABlockCrypt 

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

NewTEABlockCrypt https://en.wikipedia.org/wiki/Tiny_Encryption_Algorithm

func NewTripleDESBlockCrypt 

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

NewTripleDESBlockCrypt https://en.wikipedia.org/wiki/Triple_DES

func NewTwofishBlockCrypt 

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

NewTwofishBlockCrypt https://en.wikipedia.org/wiki/Twofish

func NewXTEABlockCrypt 

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

NewXTEABlockCrypt https://en.wikipedia.org/wiki/XTEA

type Entropy 

type Entropy interface {
	Init()
	Fill(nonce []byte)
}

Entropy defines a entropy source

type KCP 

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

KCP defines a single KCP connection

func NewKCP 

func NewKCP(conv uint32, options KCPOptions, output output_callback) *KCP

NewKCP create a new kcp state machine

'conv' must be equal in the connection peers, or else data will be silently rejected.

'output' function will be called whenever these is data to be sent on wire.

func (*KCP) Check 

func (kcp *KCP) Check() uint32

(deprecated)

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, regular, ackNoDelay bool) int

Input a packet into kcp state machine.

'regular' indicates it's a real data packet from remote, and it means it's not generated from ReedSolomon codecs.

'ackNoDelay' will trigger immediate ACK, but surely it will not be efficient in bandwidth

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)

Receive data from kcp state machine

Return number of bytes read.

Return -1 when there is no readable data.

Return -2 if len(buffer) is smaller than kcp.PeekSize().

func (*KCP) ReleaseTX 

func (kcp *KCP) ReleaseTX()

Release all cached outgoing segments

func (*KCP) ReserveBytes 

func (kcp *KCP) ReserveBytes(n int) bool

ReserveBytes keeps n bytes untouched from the beginning of the buffer, the output_callback function should be aware of this.

Return false if n >= mss

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()

(deprecated)

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 KCPOptions 

type KCPOptions struct {
	InitialTXRTOBackoff       uint8
	InitialTXRTOBackoffThresh int
	EarlyRetransmit           bool
}

type Listener 

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

Listener defines a server which will be waiting to accept incoming connections

func ListenWithOptions 

func ListenWithOptions(laddr string, block BlockCrypt, dataShards, parityShards int, fullEncrypt bool, kcpOptions KCPOptions) (*Listener, error)

ListenWithOptions listens for incoming KCP packets addressed to the local address laddr on the network "udp" with packet encryption.

'block' is the block encryption algorithm to encrypt packets.

'dataShards', 'parityShards' specify how many parity packets will be generated following the data packets.

Check https://github.com/klauspost/reedsolomon for details

func ServeConn 

func ServeConn(block BlockCrypt, dataShards, parityShards int, conn net.PacketConn, fullEncrypt bool, kcpOptions KCPOptions) (*Listener, error)

ServeConn serves KCP protocol for a single packet connection.

func (*Listener) Accept 

func (l *Listener) Accept() (net.Conn, error)

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

func (*Listener) AcceptKCP 

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

AcceptKCP accepts a KCP connection

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, and closes the socket

func (*Listener) SetDSCP 

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

SetDSCP sets the 6bit DSCP field in IPv4 header, or 8bit Traffic Class in IPv6 header.

if the underlying connection has implemented `func SetDSCP(int) error`, SetDSCP() will invoke this function instead.

func (*Listener) SetDeadline 

func (l *Listener) SetDeadline(t time.Time) error

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

func (*Listener) SetReadBuffer 

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

SetReadBuffer sets the socket read buffer for the Listener

func (*Listener) SetReadDeadline 

func (l *Listener) SetReadDeadline(t time.Time) error

SetReadDeadline implements the Conn SetReadDeadline method.

func (*Listener) SetWriteBuffer 

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

SetWriteBuffer sets the socket write buffer for the Listener

func (*Listener) SetWriteDeadline 

func (l *Listener) SetWriteDeadline(t time.Time) error

SetWriteDeadline implements the Conn SetWriteDeadline method.

type Snmp 

type Snmp struct {
	BytesSent        uint64 // bytes sent from upper level
	BytesReceived    uint64 // bytes received to upper level
	MaxConn          uint64 // max number of connections ever reached
	ActiveOpens      uint64 // accumulated active open connections
	PassiveOpens     uint64 // accumulated passive open connections
	CurrEstab        uint64 // current number of established connections
	InErrs           uint64 // UDP read errors reported from net.PacketConn
	InCsumErrors     uint64 // checksum errors from CRC32
	KCPInErrors      uint64 // packet iput errors reported from KCP
	InPkts           uint64 // incoming packets count
	OutPkts          uint64 // outgoing packets count
	InSegs           uint64 // incoming KCP segments
	OutSegs          uint64 // outgoing KCP segments
	InBytes          uint64 // UDP bytes received
	OutBytes         uint64 // UDP bytes sent
	RetransSegs      uint64 // accmulated retransmited segments
	FastRetransSegs  uint64 // accmulated fast retransmitted segments
	EarlyRetransSegs uint64 // accmulated early retransmitted segments
	LostSegs         uint64 // number of segs inferred as lost
	RepeatSegs       uint64 // number of segs duplicated
	FECRecovered     uint64 // correct packets recovered from FEC
	FECErrs          uint64 // incorrect packets recovered from FEC
	FECParityShards  uint64 // FEC segments received
	FECShortShards   uint64 // number of data shards that's not enough for recovery
}

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

func (*Snmp) Header 

func (s *Snmp) Header() []string

Header returns all field names

func (*Snmp) Reset 

func (s *Snmp) Reset()

Reset values to zero

func (*Snmp) ToSlice 

func (s *Snmp) ToSlice() []string

ToSlice returns current snmp info as slice

type TimedSched 

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

TimedSched represents the control struct for timed parallel scheduler 

var SystemTimedSched *TimedSched = NewTimedSched(runtime.NumCPU())

SystemTimedSched is the library level timed-scheduler

func NewTimedSched 

func NewTimedSched(parallel int) *TimedSched

NewTimedSched creates a parallel-scheduler with given parallelization

func (*TimedSched) Close 

func (ts *TimedSched) Close()

Close terminates this scheduler

func (*TimedSched) Put 

func (ts *TimedSched) Put(f func(), deadline time.Time)

Put a function 'f' awaiting to be executed at 'deadline'

type UDPSession 

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

UDPSession defines a KCP session implemented by UDP

func DialWithOptions 

func DialWithOptions(raddr string, block BlockCrypt, dataShards, parityShards int, fullEncrypt bool, kcpOptions KCPOptions) (*UDPSession, error)

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

'block' is the block encryption algorithm to encrypt packets.

'dataShards', 'parityShards' specify how many parity packets will be generated following the data packets.

Check https://github.com/klauspost/reedsolomon for details

func NewConn 

func NewConn(raddr string, block BlockCrypt, dataShards, parityShards int, conn net.PacketConn, fullEncrypt bool, kcpOptions KCPOptions) (*UDPSession, error)

NewConn establishes a session and talks KCP protocol over a packet connection.

func NewConn2 

func NewConn2(raddr net.Addr, block BlockCrypt, dataShards, parityShards int, conn net.PacketConn, fullEncrypt bool, kcpOptions KCPOptions) (*UDPSession, error)

NewConn2 establishes a session and talks KCP protocol over a packet connection.

func NewConn3 

func NewConn3(convid uint32, raddr net.Addr, block BlockCrypt, dataShards, parityShards int, conn net.PacketConn, fullEncrypt bool, kcpOptions KCPOptions) (*UDPSession, error)

NewConn3 establishes a session and talks KCP protocol over a packet connection.

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) GetRTO 

func (s *UDPSession) GetRTO() uint32

GetRTO gets current rto of the session

func (*UDPSession) GetSRTT 

func (s *UDPSession) GetSRTT() int32

GetSRTT gets current srtt of the session

func (*UDPSession) GetSRTTVar 

func (s *UDPSession) GetSRTTVar() int32

GetRTTVar gets current rtt variance of the 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 net.Conn

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 in IPv4 header, or 8bit Traffic Class in IPv6 header.

if the underlying connection has implemented `func SetDSCP(int) error`, SetDSCP() will invoke this function instead.

It has no effect if it's accepted from Listener.

func (*UDPSession) SetDUP 

func (s *UDPSession) SetDUP(dup int)

(deprecated)

SetDUP duplicates udp packets for kcp output.

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) SetMtu 

func (s *UDPSession) SetMtu(mtu int) bool

SetMtu sets the maximum transmission unit(not including UDP header)

func (*UDPSession) SetNoDelay 

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

SetNoDelay calls nodelay() of kcp https://github.com/skywind3000/kcp/blob/master/README.en.md#protocol-configuration

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) SetWriteDelay 

func (s *UDPSession) SetWriteDelay(delay bool)

SetWriteDelay delays write for bulk transfer until the next update interval

func (*UDPSession) Write 

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

Write implements net.Conn

func (*UDPSession) WriteBuffers 

func (s *UDPSession) WriteBuffers(v [][]byte) (n int, err error)

WriteBuffers write a vector of byte slices to the underlying connection

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