kcp

package
v1.0.4 Latest Latest
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 Go to latest Published: Jan 14, 2026 License: AGPL-3.0 Imports: 37 Imported by: 0

Documentation

Overview

Package kcp - A Fast and Reliable ARQ Protocol

Acknowledgement: 

skywind3000@github for inventing the KCP protocol
xtaci@github for translating to Golang

Index

Constants

View Source 
const (
	DataSegmentOverhead = 18
)

Variables

View Source 
var (
	ErrIOTimeout        = errors.New("Read/Write timeout")
	ErrClosedListener   = errors.New("Listener closed.")
	ErrClosedConnection = errors.New("Connection closed.")
)
View Source 
var File_transport_protocols_kcp_config_proto protoreflect.FileDescriptor

Functions

func Dial 

func Dial(ctx context.Context, dest net.Destination, kcpConfig *KcpConfig, securityConfig security.Engine, socketConfig i.Dialer) (net.Conn, error)

Dial dials a new KCP connections to the specific destination.

func NewAEADAESGCMBasedOnSeed 

func NewAEADAESGCMBasedOnSeed(seed string) cipher.AEAD

func NewKcpDialer 

func NewKcpDialer(config *KcpConfig, engine security.Engine, socketConfig i.Dialer) *kcpDialer

func NewSimpleAuthenticator 

func NewSimpleAuthenticator() cipher.AEAD

NewSimpleAuthenticator creates a new SimpleAuthenticator

Types

type AckList 

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

func NewAckList 

func NewAckList(writer SegmentWriter) *AckList

func (*AckList) Add 

func (l *AckList) Add(number uint32, timestamp uint32)

func (*AckList) Clear 

func (l *AckList) Clear(una uint32)

func (*AckList) Flush 

func (l *AckList) Flush(current uint32, rto uint32)

type AckSegment 

type AckSegment struct {
	Conv            uint16
	Option          SegmentOption
	ReceivingWindow uint32
	ReceivingNext   uint32
	Timestamp       uint32
	NumberList      []uint32
}

func NewAckSegment 

func NewAckSegment() *AckSegment

func (*AckSegment) ByteSize 

func (s *AckSegment) ByteSize() int32

func (*AckSegment) Command 

func (*AckSegment) Command() Command

func (*AckSegment) Conversation 

func (s *AckSegment) Conversation() uint16

func (*AckSegment) IsEmpty 

func (s *AckSegment) IsEmpty() bool

func (*AckSegment) IsFull 

func (s *AckSegment) IsFull() bool

func (*AckSegment) PutNumber 

func (s *AckSegment) PutNumber(number uint32)

func (*AckSegment) PutTimestamp 

func (s *AckSegment) PutTimestamp(timestamp uint32)

func (*AckSegment) Release 

func (s *AckSegment) Release()

func (*AckSegment) Serialize 

func (s *AckSegment) Serialize(b []byte)

type CmdOnlySegment 

type CmdOnlySegment struct {
	Conv          uint16
	Cmd           Command
	Option        SegmentOption
	SendingNext   uint32
	ReceivingNext uint32
	PeerRTO       uint32
}

func NewCmdOnlySegment 

func NewCmdOnlySegment() *CmdOnlySegment

func (*CmdOnlySegment) ByteSize 

func (*CmdOnlySegment) ByteSize() int32

func (*CmdOnlySegment) Command 

func (s *CmdOnlySegment) Command() Command

func (*CmdOnlySegment) Conversation 

func (s *CmdOnlySegment) Conversation() uint16

func (*CmdOnlySegment) Release 

func (*CmdOnlySegment) Release()

func (*CmdOnlySegment) Serialize 

func (s *CmdOnlySegment) Serialize(b []byte)

type Command 

type Command byte

Command is a KCP command that indicate the purpose of a Segment. 

const (
	// CommandACK indicates an AckSegment.
	CommandACK Command = 0
	// CommandData indicates a DataSegment.
	CommandData Command = 1
	// CommandTerminate indicates that peer terminates the connection.
	CommandTerminate Command = 2
	// CommandPing indicates a ping.
	CommandPing Command = 3
)

type ConnMetadata 

type ConnMetadata struct {
	LocalAddr    net.Addr
	RemoteAddr   net.Addr
	Conversation uint16
}

type Connection 

type Connection struct {
	Config *KcpConfig
	// contains filtered or unexported fields
}

Connection is a KCP connection over UDP.

func NewConnection 

func NewConnection(meta ConnMetadata, writer PacketWriter, closer io.Closer, config *KcpConfig) *Connection

NewConnection create a new KCP connection between local and remote.

func (*Connection) Close 

func (c *Connection) Close() error

Close closes the connection.

func (*Connection) CloseWrite 

func (c *Connection) CloseWrite() error

func (*Connection) Elapsed 

func (c *Connection) Elapsed() uint32

func (*Connection) HandleOption 

func (c *Connection) HandleOption(opt SegmentOption)

func (*Connection) Input 

func (c *Connection) Input(segments []Segment)

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

func (*Connection) LocalAddr 

func (c *Connection) 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 (*Connection) OnPeerClosed 

func (c *Connection) OnPeerClosed()

func (*Connection) Ping 

func (c *Connection) Ping(current uint32, cmd Command)

func (*Connection) Read 

func (c *Connection) Read(b []byte) (int, error)

Read implements the Conn Read method.

func (*Connection) ReadMultiBuffer 

func (c *Connection) ReadMultiBuffer() (buf.MultiBuffer, error)

ReadMultiBuffer implements buf.Reader.

func (*Connection) RemoteAddr 

func (c *Connection) 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 (*Connection) SetDeadline 

func (c *Connection) SetDeadline(t time.Time) error

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

func (*Connection) SetReadDeadline 

func (c *Connection) SetReadDeadline(t time.Time) error

SetReadDeadline implements the Conn SetReadDeadline method.

func (*Connection) SetState 

func (c *Connection) SetState(state State)

func (*Connection) SetWriteDeadline 

func (c *Connection) SetWriteDeadline(t time.Time) error

SetWriteDeadline implements the Conn SetWriteDeadline method.

func (*Connection) State 

func (c *Connection) State() State

func (*Connection) Terminate 

func (c *Connection) Terminate()

func (*Connection) Write 

func (c *Connection) Write(b []byte) (int, error)

Write implements io.Writer.

func (*Connection) WriteMultiBuffer 

func (c *Connection) WriteMultiBuffer(mb buf.MultiBuffer) error

WriteMultiBuffer implements buf.Writer.

type ConnectionID 

type ConnectionID struct {
	Remote net.Address
	Port   net.Port
	Conv   uint16
}

type DataSegment 

type DataSegment struct {
	Conv        uint16
	Option      SegmentOption
	Timestamp   uint32
	Number      uint32
	SendingNext uint32
	// contains filtered or unexported fields
}

func NewDataSegment 

func NewDataSegment() *DataSegment

func (*DataSegment) ByteSize 

func (s *DataSegment) ByteSize() int32

func (*DataSegment) Command 

func (*DataSegment) Command() Command

func (*DataSegment) Conversation 

func (s *DataSegment) Conversation() uint16

func (*DataSegment) Data 

func (s *DataSegment) Data() *buf.Buffer

func (*DataSegment) Detach 

func (s *DataSegment) Detach() *buf.Buffer

func (*DataSegment) Release 

func (s *DataSegment) Release()

func (*DataSegment) Serialize 

func (s *DataSegment) Serialize(b []byte)

type KCPPacketReader 

type KCPPacketReader struct {
	Security cipher.AEAD
	Header   headers.PacketHeader
}

func (*KCPPacketReader) Read 

func (r *KCPPacketReader) Read(b []byte) []Segment

type KCPPacketWriter 

type KCPPacketWriter struct {
	Header   headers.PacketHeader
	Security cipher.AEAD
	Writer   io.Writer
}

func (*KCPPacketWriter) Overhead 

func (w *KCPPacketWriter) Overhead() int

func (*KCPPacketWriter) Write 

func (w *KCPPacketWriter) Write(b []byte) (int, error)

type KcpConfig 

type KcpConfig struct {
	Mtu              uint32     `protobuf:"varint,1,opt,name=mtu,proto3" json:"mtu,omitempty"`
	Tti              uint32     `protobuf:"varint,2,opt,name=tti,proto3" json:"tti,omitempty"`
	UplinkCapacity   uint32     `protobuf:"varint,3,opt,name=uplink_capacity,json=uplinkCapacity,proto3" json:"uplink_capacity,omitempty"`
	DownlinkCapacity uint32     `protobuf:"varint,4,opt,name=downlink_capacity,json=downlinkCapacity,proto3" json:"downlink_capacity,omitempty"`
	Congestion       bool       `protobuf:"varint,5,opt,name=congestion,proto3" json:"congestion,omitempty"`
	WriteBuffer      uint32     `protobuf:"varint,6,opt,name=write_buffer,json=writeBuffer,proto3" json:"write_buffer,omitempty"`
	ReadBuffer       uint32     `protobuf:"varint,7,opt,name=read_buffer,json=readBuffer,proto3" json:"read_buffer,omitempty"`
	HeaderConfig     *anypb.Any `protobuf:"bytes,8,opt,name=header_config,json=headerConfig,proto3" json:"header_config,omitempty"`
	Seed             string     `protobuf:"bytes,10,opt,name=seed,proto3" json:"seed,omitempty"`
	// contains filtered or unexported fields
}

func (*KcpConfig) Descriptor deprecated 

func (*KcpConfig) Descriptor() ([]byte, []int)

Deprecated: Use KcpConfig.ProtoReflect.Descriptor instead.

func (*KcpConfig) GetCongestion 

func (x *KcpConfig) GetCongestion() bool

func (*KcpConfig) GetDownlinkCapacity 

func (x *KcpConfig) GetDownlinkCapacity() uint32

func (*KcpConfig) GetDownlinkCapacityValue 

func (c *KcpConfig) GetDownlinkCapacityValue() uint32

GetDownlinkCapacityValue returns the value of DownlinkCapacity settings.

func (*KcpConfig) GetHeaderConfig 

func (x *KcpConfig) GetHeaderConfig() *anypb.Any

func (*KcpConfig) GetMTUValue 

func (c *KcpConfig) GetMTUValue() uint32

GetMTUValue returns the value of MTU settings.

func (*KcpConfig) GetMtu 

func (x *KcpConfig) GetMtu() uint32

func (*KcpConfig) GetPackerHeader 

func (c *KcpConfig) GetPackerHeader() (headers.PacketHeader, error)

func (*KcpConfig) GetReadBuffer 

func (x *KcpConfig) GetReadBuffer() uint32

func (*KcpConfig) GetReadBufferSize 

func (c *KcpConfig) GetReadBufferSize() uint32

GetReadBufferSize returns the size of ReadBuffer in bytes.

func (*KcpConfig) GetReceivingBufferSize 

func (c *KcpConfig) GetReceivingBufferSize() uint32

func (*KcpConfig) GetReceivingInFlightSize 

func (c *KcpConfig) GetReceivingInFlightSize() uint32

func (*KcpConfig) GetSecurity 

func (c *KcpConfig) GetSecurity() (cipher.AEAD, error)

GetSecurity returns the security settings.

func (*KcpConfig) GetSeed 

func (x *KcpConfig) GetSeed() string

func (*KcpConfig) GetSendingBufferSize 

func (c *KcpConfig) GetSendingBufferSize() uint32

func (*KcpConfig) GetSendingInFlightSize 

func (c *KcpConfig) GetSendingInFlightSize() uint32

func (*KcpConfig) GetTTIValue 

func (c *KcpConfig) GetTTIValue() uint32

GetTTIValue returns the value of TTI settings.

func (*KcpConfig) GetTti 

func (x *KcpConfig) GetTti() uint32

func (*KcpConfig) GetUplinkCapacity 

func (x *KcpConfig) GetUplinkCapacity() uint32

func (*KcpConfig) GetUplinkCapacityValue 

func (c *KcpConfig) GetUplinkCapacityValue() uint32

GetUplinkCapacityValue returns the value of UplinkCapacity settings.

func (*KcpConfig) GetWriteBuffer 

func (x *KcpConfig) GetWriteBuffer() uint32

func (*KcpConfig) GetWriteBufferSize 

func (c *KcpConfig) GetWriteBufferSize() uint32

GetWriteBufferSize returns the size of WriterBuffer in bytes.

func (*KcpConfig) ProtoMessage 

func (*KcpConfig) ProtoMessage()

func (*KcpConfig) ProtoReflect 

func (x *KcpConfig) ProtoReflect() protoreflect.Message

func (*KcpConfig) Reset 

func (x *KcpConfig) Reset()

func (*KcpConfig) String 

func (x *KcpConfig) String() string

type Listener 

type Listener struct {
	sync.Mutex
	// contains filtered or unexported fields
}

Listener defines a server listening for connections

func Listen 

func Listen(ctx context.Context, addr net.Destination,
	config *KcpConfig, tlsConfig *tls.Config,
	so *dlhelper.SocketSetting, h func(net.Conn)) (*Listener, error)

func (*Listener) ActiveConnections 

func (l *Listener) ActiveConnections() int

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) OnReceive 

func (l *Listener) OnReceive(payload *buf.Buffer, src net.Destination)

func (*Listener) Remove 

func (l *Listener) Remove(id ConnectionID)

type PacketReader 

type PacketReader interface {
	Read([]byte) []Segment
}

type PacketWriter 

type PacketWriter interface {
	Overhead() int
	io.Writer
}

type ReceivingWindow 

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

func NewReceivingWindow 

func NewReceivingWindow() *ReceivingWindow

func (*ReceivingWindow) Has 

func (w *ReceivingWindow) Has(id uint32) bool

func (*ReceivingWindow) Remove 

func (w *ReceivingWindow) Remove(id uint32) *DataSegment

func (*ReceivingWindow) Set 

func (w *ReceivingWindow) Set(id uint32, value *DataSegment) bool

type ReceivingWorker 

type ReceivingWorker struct {
	sync.RWMutex
	// contains filtered or unexported fields
}

func NewReceivingWorker 

func NewReceivingWorker(kcp *Connection) *ReceivingWorker

func (*ReceivingWorker) CloseRead 

func (*ReceivingWorker) CloseRead()

func (*ReceivingWorker) Flush 

func (w *ReceivingWorker) Flush(current uint32)

func (*ReceivingWorker) IsDataAvailable 

func (w *ReceivingWorker) IsDataAvailable() bool

func (*ReceivingWorker) NextNumber 

func (w *ReceivingWorker) NextNumber() uint32

func (*ReceivingWorker) ProcessSegment 

func (w *ReceivingWorker) ProcessSegment(seg *DataSegment)

func (*ReceivingWorker) ProcessSendingNext 

func (w *ReceivingWorker) ProcessSendingNext(number uint32)

func (*ReceivingWorker) Read 

func (w *ReceivingWorker) Read(b []byte) int

func (*ReceivingWorker) ReadMultiBuffer 

func (w *ReceivingWorker) ReadMultiBuffer() buf.MultiBuffer

func (*ReceivingWorker) Release 

func (w *ReceivingWorker) Release()

func (*ReceivingWorker) UpdateNecessary 

func (w *ReceivingWorker) UpdateNecessary() bool

func (*ReceivingWorker) Write 

func (w *ReceivingWorker) Write(seg Segment) error

type RetryableWriter 

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

func (*RetryableWriter) Write 

func (w *RetryableWriter) Write(seg Segment) error

type RoundTripInfo 

type RoundTripInfo struct {
	sync.RWMutex
	// contains filtered or unexported fields
}

func (*RoundTripInfo) SmoothedTime 

func (info *RoundTripInfo) SmoothedTime() uint32

func (*RoundTripInfo) Timeout 

func (info *RoundTripInfo) Timeout() uint32

func (*RoundTripInfo) Update 

func (info *RoundTripInfo) Update(rtt uint32, current uint32)

func (*RoundTripInfo) UpdatePeerRTO 

func (info *RoundTripInfo) UpdatePeerRTO(rto uint32, current uint32)

type Segment 

type Segment interface {
	Release()
	Conversation() uint16
	Command() Command
	ByteSize() int32
	Serialize([]byte)
	// contains filtered or unexported methods
}

func ReadSegment 

func ReadSegment(buf []byte) (Segment, []byte)

type SegmentOption 

type SegmentOption byte
const (
	SegmentOptionClose SegmentOption = 1
)

type SegmentWriter 

type SegmentWriter interface {
	Write(seg Segment) error
}

func NewRetryableWriter 

func NewRetryableWriter(writer SegmentWriter) SegmentWriter

func NewSegmentWriter 

func NewSegmentWriter(writer io.Writer) SegmentWriter

type SendingWindow 

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

func NewSendingWindow 

func NewSendingWindow(writer SegmentWriter, onPacketLoss func(uint32)) *SendingWindow

func (*SendingWindow) Clear 

func (sw *SendingWindow) Clear(una uint32)

func (*SendingWindow) FirstNumber 

func (sw *SendingWindow) FirstNumber() uint32

func (*SendingWindow) Flush 

func (sw *SendingWindow) Flush(current uint32, rto uint32, maxInFlightSize uint32)

func (*SendingWindow) HandleFastAck 

func (sw *SendingWindow) HandleFastAck(number uint32, rto uint32)

func (*SendingWindow) IsEmpty 

func (sw *SendingWindow) IsEmpty() bool

func (*SendingWindow) Len 

func (sw *SendingWindow) Len() uint32

func (*SendingWindow) Push 

func (sw *SendingWindow) Push(number uint32, b *buf.Buffer)

func (*SendingWindow) Release 

func (sw *SendingWindow) Release()

func (*SendingWindow) Remove 

func (sw *SendingWindow) Remove(number uint32) bool

func (*SendingWindow) Visit 

func (sw *SendingWindow) Visit(visitor func(seg *DataSegment) bool)

type SendingWorker 

type SendingWorker struct {
	sync.RWMutex
	// contains filtered or unexported fields
}

func NewSendingWorker 

func NewSendingWorker(kcp *Connection) *SendingWorker

func (*SendingWorker) CloseWrite 

func (w *SendingWorker) CloseWrite()

func (*SendingWorker) FindFirstUnacknowledged 

func (w *SendingWorker) FindFirstUnacknowledged()

func (*SendingWorker) FirstUnacknowledged 

func (w *SendingWorker) FirstUnacknowledged() uint32

func (*SendingWorker) Flush 

func (w *SendingWorker) Flush(current uint32)

func (*SendingWorker) IsEmpty 

func (w *SendingWorker) IsEmpty() bool

func (*SendingWorker) OnPacketLoss 

func (w *SendingWorker) OnPacketLoss(lossRate uint32)

func (*SendingWorker) ProcessReceivingNext 

func (w *SendingWorker) ProcessReceivingNext(nextNumber uint32)

func (*SendingWorker) ProcessReceivingNextWithoutLock 

func (w *SendingWorker) ProcessReceivingNextWithoutLock(nextNumber uint32)

func (*SendingWorker) ProcessSegment 

func (w *SendingWorker) ProcessSegment(current uint32, seg *AckSegment, rto uint32)

func (*SendingWorker) Push 

func (w *SendingWorker) Push(b *buf.Buffer) bool

func (*SendingWorker) Release 

func (w *SendingWorker) Release()

func (*SendingWorker) UpdateNecessary 

func (w *SendingWorker) UpdateNecessary() bool

func (*SendingWorker) Write 

func (w *SendingWorker) Write(seg Segment) error

type SimpleAuthenticator 

type SimpleAuthenticator struct{}

SimpleAuthenticator is a legacy AEAD used for KCP encryption.

func (*SimpleAuthenticator) NonceSize 

func (*SimpleAuthenticator) NonceSize() int

NonceSize implements cipher.AEAD.NonceSize().

func (*SimpleAuthenticator) Open 

func (a *SimpleAuthenticator) Open(dst, nonce, cipherText, extra []byte) ([]byte, error)

Open implements cipher.AEAD.Open().

func (*SimpleAuthenticator) Overhead 

func (*SimpleAuthenticator) Overhead() int

Overhead implements cipher.AEAD.NonceSize().

func (*SimpleAuthenticator) Seal 

func (a *SimpleAuthenticator) Seal(dst, nonce, plain, extra []byte) []byte

Seal implements cipher.AEAD.Seal().

type SimpleSegmentWriter 

type SimpleSegmentWriter struct {
	sync.Mutex
	// contains filtered or unexported fields
}

func (*SimpleSegmentWriter) Write 

func (w *SimpleSegmentWriter) Write(seg Segment) error

type State 

type State int32

State of the connection 

const (
	StateActive          State = 0 // Connection is active
	StateReadyToClose    State = 1 // Connection is closed locally
	StatePeerClosed      State = 2 // Connection is closed on remote
	StateTerminating     State = 3 // Connection is ready to be destroyed locally
	StatePeerTerminating State = 4 // Connection is ready to be destroyed on remote
	StateTerminated      State = 5 // Connection is destroyed.
)

func (State) Is 

func (s State) Is(states ...State) bool

Is returns true if current State is one of the candidates.

type Updater 

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

func NewUpdater 

func NewUpdater(interval uint32, shouldContinue func() bool, shouldTerminate func() bool, updateFunc func()) *Updater

func (*Updater) Interval 

func (u *Updater) Interval() time.Duration

func (*Updater) SetInterval 

func (u *Updater) SetInterval(d time.Duration)

func (*Updater) WakeUp 

func (u *Updater) WakeUp()

type Writer 

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

func (*Writer) Close 

func (w *Writer) Close() error

func (*Writer) Write 

func (w *Writer) Write(payload []byte) (int, error)

Source Files

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