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connection.go
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connection.go
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package kcp
import (
"errors"
"io"
"net"
"sync"
"time"
"github.com/v2ray/v2ray-core/common/alloc"
"github.com/v2ray/v2ray-core/common/log"
"github.com/v2ray/v2ray-core/common/signal"
)
var (
errTimeout = errors.New("i/o timeout")
errBrokenPipe = errors.New("broken pipe")
errClosedListener = errors.New("Listener closed.")
errClosedConnection = errors.New("Connection closed.")
)
const (
headerSize uint32 = 2
)
type Command byte
var (
CommandData Command = 0
CommandTerminate Command = 1
)
type Option byte
var (
OptionClose Option = 1
)
type ConnState byte
var (
ConnStateActive ConnState = 0
ConnStateReadyToClose ConnState = 1
ConnStatePeerClosed ConnState = 2
ConnStateClosed ConnState = 4
)
func nowMillisec() int64 {
now := time.Now()
return now.Unix()*1000 + int64(now.Nanosecond()/1000000)
}
// Connection is a KCP connection over UDP.
type Connection struct {
sync.RWMutex
state ConnState
kcp *KCP // the core ARQ
kcpAccess sync.Mutex
block Authenticator
needUpdate bool
local, remote net.Addr
rd time.Time // read deadline
wd time.Time // write deadline
chReadEvent chan struct{}
writer io.WriteCloser
since int64
terminateOnce signal.Once
writeBufferSize uint32
}
// NewConnection create a new KCP connection between local and remote.
func NewConnection(conv uint32, writerCloser io.WriteCloser, local *net.UDPAddr, remote *net.UDPAddr, block Authenticator) *Connection {
conn := new(Connection)
conn.local = local
conn.chReadEvent = make(chan struct{}, 1)
conn.remote = remote
conn.block = block
conn.writer = writerCloser
conn.since = nowMillisec()
conn.writeBufferSize = effectiveConfig.WriteBuffer / effectiveConfig.Mtu
mtu := effectiveConfig.Mtu - uint32(block.HeaderSize()) - headerSize
conn.kcp = NewKCP(conv, mtu, effectiveConfig.GetSendingWindowSize(), effectiveConfig.GetReceivingWindowSize(), conn.writeBufferSize, conn.output)
conn.kcp.NoDelay(effectiveConfig.Tti, 2, effectiveConfig.Congestion)
conn.kcp.current = conn.Elapsed()
go conn.updateTask()
return conn
}
func (this *Connection) Elapsed() uint32 {
return uint32(nowMillisec() - this.since)
}
// Read implements the Conn Read method.
func (this *Connection) Read(b []byte) (int, error) {
if this == nil || this.state == ConnStateReadyToClose || this.state == ConnStateClosed {
return 0, io.EOF
}
for {
this.RLock()
if this.state == ConnStateReadyToClose || this.state == ConnStateClosed {
this.RUnlock()
return 0, io.EOF
}
if !this.rd.IsZero() && this.rd.Before(time.Now()) {
this.RUnlock()
return 0, errTimeout
}
this.RUnlock()
this.kcpAccess.Lock()
nBytes := this.kcp.Recv(b)
this.kcpAccess.Unlock()
if nBytes > 0 {
return nBytes, nil
}
select {
case <-this.chReadEvent:
case <-time.After(time.Second):
}
}
}
// Write implements the Conn Write method.
func (this *Connection) Write(b []byte) (int, error) {
if this == nil ||
this.state == ConnStateReadyToClose ||
this.state == ConnStatePeerClosed ||
this.state == ConnStateClosed {
return 0, io.ErrClosedPipe
}
totalWritten := 0
for {
this.RLock()
if this.state == ConnStateReadyToClose ||
this.state == ConnStatePeerClosed ||
this.state == ConnStateClosed {
this.RUnlock()
return totalWritten, io.ErrClosedPipe
}
this.RUnlock()
this.kcpAccess.Lock()
nBytes := this.kcp.Send(b[totalWritten:])
if nBytes > 0 {
totalWritten += nBytes
if totalWritten == len(b) {
this.kcpAccess.Unlock()
return totalWritten, nil
}
}
this.kcpAccess.Unlock()
if !this.wd.IsZero() && this.wd.Before(time.Now()) {
return totalWritten, errTimeout
}
// Sending windows is 1024 for the moment. This amount is not gonna sent in 1 sec.
time.Sleep(time.Second)
}
}
func (this *Connection) Terminate() {
if this == nil || this.state == ConnStateClosed {
return
}
this.Lock()
defer this.Unlock()
if this.state == ConnStateClosed {
return
}
this.state = ConnStateClosed
this.writer.Close()
}
func (this *Connection) NotifyTermination() {
for i := 0; i < 16; i++ {
this.RLock()
if this.state == ConnStateClosed {
this.RUnlock()
break
}
this.RUnlock()
buffer := alloc.NewSmallBuffer().Clear()
buffer.AppendBytes(byte(CommandTerminate), byte(OptionClose), byte(0), byte(0), byte(0), byte(0))
this.outputBuffer(buffer)
time.Sleep(time.Second)
}
this.Terminate()
}
func (this *Connection) ForceTimeout() {
if this == nil {
return
}
for i := 0; i < 5; i++ {
if this.state == ConnStateClosed {
return
}
time.Sleep(time.Minute)
}
go this.terminateOnce.Do(this.NotifyTermination)
}
// Close closes the connection.
func (this *Connection) Close() error {
if this == nil || this.state == ConnStateClosed || this.state == ConnStateReadyToClose {
return errClosedConnection
}
log.Debug("KCP|Connection: Closing connection to ", this.remote)
this.Lock()
defer this.Unlock()
if this.state == ConnStateActive {
this.state = ConnStateReadyToClose
if this.kcp.WaitSnd() == 0 {
go this.terminateOnce.Do(this.NotifyTermination)
} else {
go this.ForceTimeout()
}
}
if this.state == ConnStatePeerClosed {
go this.Terminate()
}
return nil
}
// LocalAddr returns the local network address. The Addr returned is shared by all invocations of LocalAddr, so do not modify it.
func (this *Connection) LocalAddr() net.Addr {
if this == nil {
return nil
}
return this.local
}
// RemoteAddr returns the remote network address. The Addr returned is shared by all invocations of RemoteAddr, so do not modify it.
func (this *Connection) RemoteAddr() net.Addr {
if this == nil {
return nil
}
return this.remote
}
// SetDeadline sets the deadline associated with the listener. A zero time value disables the deadline.
func (this *Connection) SetDeadline(t time.Time) error {
if this == nil || this.state != ConnStateActive {
return errClosedConnection
}
this.Lock()
defer this.Unlock()
this.rd = t
this.wd = t
return nil
}
// SetReadDeadline implements the Conn SetReadDeadline method.
func (this *Connection) SetReadDeadline(t time.Time) error {
if this == nil || this.state != ConnStateActive {
return errClosedConnection
}
this.Lock()
defer this.Unlock()
this.rd = t
return nil
}
// SetWriteDeadline implements the Conn SetWriteDeadline method.
func (this *Connection) SetWriteDeadline(t time.Time) error {
if this == nil || this.state != ConnStateActive {
return errClosedConnection
}
this.Lock()
defer this.Unlock()
this.wd = t
return nil
}
func (this *Connection) outputBuffer(payload *alloc.Buffer) {
defer payload.Release()
if this == nil {
return
}
this.RLock()
defer this.RUnlock()
if this.state == ConnStatePeerClosed || this.state == ConnStateClosed {
return
}
this.block.Seal(payload)
this.writer.Write(payload.Value)
}
func (this *Connection) output(payload []byte) {
if this == nil || this.state == ConnStateClosed {
return
}
if this.state == ConnStateReadyToClose && this.kcp.WaitSnd() == 0 {
go this.terminateOnce.Do(this.NotifyTermination)
}
if len(payload) < IKCP_OVERHEAD {
return
}
buffer := alloc.NewBuffer().Clear().Append(payload)
cmd := CommandData
opt := Option(0)
if this.state == ConnStateReadyToClose {
opt = OptionClose
}
buffer.Prepend([]byte{byte(cmd), byte(opt)})
this.outputBuffer(buffer)
}
// kcp update, input loop
func (this *Connection) updateTask() {
for this.state != ConnStateClosed {
current := this.Elapsed()
this.kcpAccess.Lock()
this.kcp.Update(current)
this.kcpAccess.Unlock()
time.Sleep(time.Duration(effectiveConfig.Tti) * time.Millisecond)
}
}
func (this *Connection) notifyReadEvent() {
select {
case this.chReadEvent <- struct{}{}:
default:
}
}
func (this *Connection) MarkPeerClose() {
this.Lock()
defer this.Unlock()
if this.state == ConnStateReadyToClose {
this.state = ConnStateClosed
go this.Terminate()
return
}
if this.state == ConnStateActive {
this.state = ConnStatePeerClosed
}
this.kcpAccess.Lock()
this.kcp.ClearSendQueue()
this.kcpAccess.Unlock()
}
func (this *Connection) kcpInput(data []byte) {
cmd := Command(data[0])
opt := Option(data[1])
if cmd == CommandTerminate {
go this.Terminate()
return
}
if opt == OptionClose {
go this.MarkPeerClose()
}
this.kcpAccess.Lock()
this.kcp.current = this.Elapsed()
this.kcp.Input(data[2:])
this.kcpAccess.Unlock()
this.notifyReadEvent()
}
func (this *Connection) FetchInputFrom(conn net.Conn) {
go func() {
for {
payload := alloc.NewBuffer()
nBytes, err := conn.Read(payload.Value)
if err != nil {
return
}
payload.Slice(0, nBytes)
if this.block.Open(payload) {
this.kcpInput(payload.Value)
} else {
log.Info("KCP|Connection: Invalid response from ", conn.RemoteAddr())
}
payload.Release()
}
}()
}
func (this *Connection) Reusable() bool {
return false
}
func (this *Connection) SetReusable(b bool) {}