mirror of
https://github.com/v2fly/v2ray-core.git
synced 2024-09-07 04:24:23 -04:00
478 lines
11 KiB
Go
478 lines
11 KiB
Go
package kcp
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import (
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"errors"
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"io"
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"net"
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"sync"
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"sync/atomic"
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"time"
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"github.com/v2ray/v2ray-core/common/alloc"
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"github.com/v2ray/v2ray-core/common/log"
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)
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var (
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errTimeout = errors.New("i/o timeout")
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errBrokenPipe = errors.New("broken pipe")
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errClosedListener = errors.New("Listener closed.")
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errClosedConnection = errors.New("Connection closed.")
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)
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type State int32
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const (
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StateActive State = 0
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StateReadyToClose State = 1
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StatePeerClosed State = 2
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StateTerminating State = 3
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StateTerminated State = 4
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)
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const (
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headerSize uint32 = 2
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)
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func nowMillisec() int64 {
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now := time.Now()
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return now.Unix()*1000 + int64(now.Nanosecond()/1000000)
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}
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type RountTripInfo struct {
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sync.RWMutex
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variation uint32
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srtt uint32
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rto uint32
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minRtt uint32
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}
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func (this *RountTripInfo) Update(rtt uint32) {
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if rtt > 0x7FFFFFFF {
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return
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}
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this.Lock()
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defer this.Unlock()
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// https://tools.ietf.org/html/rfc6298
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if this.srtt == 0 {
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this.srtt = rtt
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this.variation = rtt / 2
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} else {
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delta := rtt - this.srtt
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if this.srtt > rtt {
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delta = this.srtt - rtt
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}
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this.variation = (3*this.variation + delta) / 4
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this.srtt = (7*this.srtt + rtt) / 8
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if this.srtt < this.minRtt {
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this.srtt = this.minRtt
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}
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}
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var rto uint32
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if this.minRtt < 4*this.variation {
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rto = this.srtt + 4*this.variation
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} else {
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rto = this.srtt + this.variation
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}
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if rto > 10000 {
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rto = 10000
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}
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this.rto = rto * 3 / 2
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}
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func (this *RountTripInfo) Timeout() uint32 {
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this.RLock()
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defer this.RUnlock()
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return this.rto
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}
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func (this *RountTripInfo) SmoothedTime() uint32 {
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this.RLock()
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defer this.RUnlock()
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return this.srtt
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}
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// Connection is a KCP connection over UDP.
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type Connection struct {
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block Authenticator
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local, remote net.Addr
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rd time.Time
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wd time.Time // write deadline
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writer io.WriteCloser
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since int64
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dataInputCond *sync.Cond
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conv uint16
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state State
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stateBeginTime uint32
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lastIncomingTime uint32
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sendingUpdated bool
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lastPingTime uint32
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mss uint32
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roundTrip *RountTripInfo
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interval uint32
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receivingWorker *ReceivingWorker
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sendingWorker *SendingWorker
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fastresend uint32
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congestionControl bool
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output *BufferedSegmentWriter
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}
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// NewConnection create a new KCP connection between local and remote.
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func NewConnection(conv uint16, writerCloser io.WriteCloser, local *net.UDPAddr, remote *net.UDPAddr, block Authenticator) *Connection {
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log.Info("KCP|Connection: creating connection ", conv)
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conn := new(Connection)
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conn.local = local
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conn.remote = remote
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conn.block = block
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conn.writer = writerCloser
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conn.since = nowMillisec()
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conn.dataInputCond = sync.NewCond(new(sync.Mutex))
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authWriter := &AuthenticationWriter{
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Authenticator: block,
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Writer: writerCloser,
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}
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conn.conv = conv
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conn.output = NewSegmentWriter(authWriter)
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conn.mss = authWriter.Mtu() - DataSegmentOverhead
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conn.roundTrip = &RountTripInfo{
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rto: 100,
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minRtt: effectiveConfig.Tti,
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}
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conn.interval = effectiveConfig.Tti
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conn.receivingWorker = NewReceivingWorker(conn)
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conn.fastresend = 2
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conn.congestionControl = effectiveConfig.Congestion
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conn.sendingWorker = NewSendingWorker(conn)
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go conn.updateTask()
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return conn
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}
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func (this *Connection) Elapsed() uint32 {
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return uint32(nowMillisec() - this.since)
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}
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// Read implements the Conn Read method.
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func (this *Connection) Read(b []byte) (int, error) {
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if this == nil {
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return 0, io.EOF
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}
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for {
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if this.State() == StateReadyToClose || this.State() == StateTerminating || this.State() == StateTerminated {
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return 0, io.EOF
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}
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nBytes := this.receivingWorker.Read(b)
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if nBytes > 0 {
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return nBytes, nil
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}
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var timer *time.Timer
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if !this.rd.IsZero() {
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duration := this.rd.Sub(time.Now())
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if duration <= 0 {
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return 0, errTimeout
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}
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timer = time.AfterFunc(duration, this.dataInputCond.Signal)
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}
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this.dataInputCond.L.Lock()
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this.dataInputCond.Wait()
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this.dataInputCond.L.Unlock()
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if timer != nil {
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timer.Stop()
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}
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if !this.rd.IsZero() && this.rd.Before(time.Now()) {
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return 0, errTimeout
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}
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}
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}
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// Write implements the Conn Write method.
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func (this *Connection) Write(b []byte) (int, error) {
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if this == nil || this.State() != StateActive {
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return 0, io.ErrClosedPipe
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}
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totalWritten := 0
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for {
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if this == nil || this.State() != StateActive {
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return totalWritten, io.ErrClosedPipe
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}
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nBytes := this.sendingWorker.Push(b[totalWritten:])
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if nBytes > 0 {
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totalWritten += nBytes
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if totalWritten == len(b) {
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return totalWritten, nil
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}
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}
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if !this.wd.IsZero() && this.wd.Before(time.Now()) {
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return totalWritten, errTimeout
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}
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// Sending windows is 1024 for the moment. This amount is not gonna sent in 1 sec.
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time.Sleep(time.Second)
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}
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}
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func (this *Connection) SetState(state State) {
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current := this.Elapsed()
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atomic.StoreInt32((*int32)(&this.state), int32(state))
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atomic.StoreUint32(&this.stateBeginTime, current)
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log.Info("KCP|Connection: Entering state ", state, " at ", current)
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switch state {
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case StateReadyToClose:
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this.receivingWorker.CloseRead()
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case StatePeerClosed:
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this.sendingWorker.CloseWrite()
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case StateTerminating:
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this.receivingWorker.CloseRead()
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this.sendingWorker.CloseWrite()
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case StateTerminated:
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this.receivingWorker.CloseRead()
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this.sendingWorker.CloseWrite()
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}
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}
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// Close closes the connection.
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func (this *Connection) Close() error {
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if this == nil {
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return errClosedConnection
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}
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this.dataInputCond.Broadcast()
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state := this.State()
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if state == StateReadyToClose ||
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state == StateTerminating ||
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state == StateTerminated {
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return errClosedConnection
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}
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log.Info("KCP|Connection: Closing connection to ", this.remote)
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if state == StateActive {
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this.SetState(StateReadyToClose)
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}
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if state == StatePeerClosed {
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this.SetState(StateTerminating)
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}
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return nil
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}
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// LocalAddr returns the local network address. The Addr returned is shared by all invocations of LocalAddr, so do not modify it.
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func (this *Connection) LocalAddr() net.Addr {
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if this == nil {
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return nil
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}
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return this.local
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}
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// RemoteAddr returns the remote network address. The Addr returned is shared by all invocations of RemoteAddr, so do not modify it.
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func (this *Connection) RemoteAddr() net.Addr {
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if this == nil {
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return nil
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}
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return this.remote
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}
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// SetDeadline sets the deadline associated with the listener. A zero time value disables the deadline.
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func (this *Connection) SetDeadline(t time.Time) error {
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if err := this.SetReadDeadline(t); err != nil {
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return err
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}
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if err := this.SetWriteDeadline(t); err != nil {
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return err
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}
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return nil
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}
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// SetReadDeadline implements the Conn SetReadDeadline method.
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func (this *Connection) SetReadDeadline(t time.Time) error {
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if this == nil || this.State() != StateActive {
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return errClosedConnection
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}
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this.rd = t
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return nil
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}
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// SetWriteDeadline implements the Conn SetWriteDeadline method.
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func (this *Connection) SetWriteDeadline(t time.Time) error {
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if this == nil || this.State() != StateActive {
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return errClosedConnection
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}
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this.wd = t
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return nil
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}
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// kcp update, input loop
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func (this *Connection) updateTask() {
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for this.State() != StateTerminated {
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this.flush()
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interval := time.Duration(effectiveConfig.Tti) * time.Millisecond
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if this.State() == StateTerminating {
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interval = time.Second
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}
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time.Sleep(interval)
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}
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this.Terminate()
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}
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func (this *Connection) FetchInputFrom(conn io.Reader) {
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go func() {
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payload := alloc.NewBuffer()
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defer payload.Release()
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for {
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payload.Reset()
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nBytes, err := conn.Read(payload.Value)
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if err != nil {
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return
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}
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payload.Slice(0, nBytes)
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if this.block.Open(payload) {
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this.Input(payload.Value)
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}
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}
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}()
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}
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func (this *Connection) Reusable() bool {
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return false
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}
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func (this *Connection) SetReusable(b bool) {}
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func (this *Connection) Terminate() {
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if this == nil || this.writer == nil {
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return
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}
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log.Info("KCP|Connection: Terminating connection to ", this.RemoteAddr())
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this.writer.Close()
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}
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func (this *Connection) HandleOption(opt SegmentOption) {
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if (opt & SegmentOptionClose) == SegmentOptionClose {
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this.OnPeerClosed()
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}
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}
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func (this *Connection) OnPeerClosed() {
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state := this.State()
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if state == StateReadyToClose {
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this.SetState(StateTerminating)
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}
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if state == StateActive {
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this.SetState(StatePeerClosed)
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}
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}
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// Input when you received a low level packet (eg. UDP packet), call it
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func (this *Connection) Input(data []byte) int {
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current := this.Elapsed()
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atomic.StoreUint32(&this.lastIncomingTime, current)
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var seg Segment
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for {
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seg, data = ReadSegment(data)
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if seg == nil {
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break
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}
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switch seg := seg.(type) {
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case *DataSegment:
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this.HandleOption(seg.Opt)
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this.receivingWorker.ProcessSegment(seg)
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this.dataInputCond.Signal()
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case *AckSegment:
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this.HandleOption(seg.Opt)
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this.sendingWorker.ProcessSegment(current, seg)
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case *CmdOnlySegment:
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this.HandleOption(seg.Opt)
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if seg.Cmd == SegmentCommandTerminated {
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state := this.State()
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if state == StateActive ||
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state == StateReadyToClose ||
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state == StatePeerClosed {
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this.SetState(StateTerminating)
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} else if state == StateTerminating {
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this.SetState(StateTerminated)
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}
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}
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this.sendingWorker.ProcessReceivingNext(seg.ReceivinNext)
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this.receivingWorker.ProcessSendingNext(seg.SendingNext)
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default:
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}
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}
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return 0
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}
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func (this *Connection) flush() {
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current := this.Elapsed()
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if this.State() == StateTerminated {
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return
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}
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if this.State() == StateActive && current-atomic.LoadUint32(&this.lastIncomingTime) >= 30000 {
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this.Close()
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}
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if this.State() == StateTerminating {
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this.output.Write(&CmdOnlySegment{
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Conv: this.conv,
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Cmd: SegmentCommandTerminated,
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})
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this.output.Flush()
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if current-atomic.LoadUint32(&this.stateBeginTime) > 8000 {
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this.SetState(StateTerminated)
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}
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return
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}
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if this.State() == StateReadyToClose && current-atomic.LoadUint32(&this.stateBeginTime) > 15000 {
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this.SetState(StateTerminating)
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}
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// flush acknowledges
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this.receivingWorker.Flush(current)
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this.sendingWorker.Flush(current)
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if this.sendingWorker.PingNecessary() || this.receivingWorker.PingNecessary() || current-atomic.LoadUint32(&this.lastPingTime) >= 5000 {
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seg := NewCmdOnlySegment()
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seg.Conv = this.conv
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seg.Cmd = SegmentCommandPing
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seg.ReceivinNext = this.receivingWorker.nextNumber
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seg.SendingNext = this.sendingWorker.firstUnacknowledged
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if this.State() == StateReadyToClose {
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seg.Opt = SegmentOptionClose
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}
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this.output.Write(seg)
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this.lastPingTime = current
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this.sendingUpdated = false
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seg.Release()
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}
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// flash remain segments
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this.output.Flush()
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}
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func (this *Connection) State() State {
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return State(atomic.LoadInt32((*int32)(&this.state)))
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}
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