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conn.go
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conn.go
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package nps_mux
import (
"errors"
"io"
"log"
"math"
"net"
"runtime"
"sync"
"sync/atomic"
"time"
)
type conn struct {
net.Conn
connStatusOkCh chan struct{}
connStatusFailCh chan struct{}
connId int32
isClose bool
closingFlag bool // closing conn flag
receiveWindow *receiveWindow
sendWindow *sendWindow
once sync.Once
}
func NewConn(connId int32, mux *Mux) *conn {
c := &conn{
connStatusOkCh: make(chan struct{}),
connStatusFailCh: make(chan struct{}),
connId: connId,
receiveWindow: new(receiveWindow),
sendWindow: new(sendWindow),
once: sync.Once{},
}
c.receiveWindow.New(mux)
c.sendWindow.New(mux)
return c
}
func (s *conn) Read(buf []byte) (n int, err error) {
if s.isClose || buf == nil {
return 0, errors.New("the conn has closed")
}
if len(buf) == 0 {
return 0, nil
}
// waiting for takeout from receive window finish or timeout
n, err = s.receiveWindow.Read(buf, s.connId)
return
}
func (s *conn) Write(buf []byte) (n int, err error) {
if s.isClose {
return 0, errors.New("the conn has closed")
}
if s.closingFlag {
return 0, errors.New("io: write on closed conn")
}
if len(buf) == 0 {
return 0, nil
}
n, err = s.sendWindow.WriteFull(buf, s.connId)
return
}
func (s *conn) Close() (err error) {
s.once.Do(s.closeProcess)
return
}
func (s *conn) closeProcess() {
s.isClose = true
s.receiveWindow.mux.connMap.Delete(s.connId)
if !s.receiveWindow.mux.IsClose {
// if server or user close the conn while reading, will Get a io.EOF
// and this Close method will be invoke, send this signal to close other side
s.receiveWindow.mux.sendInfo(muxConnClose, s.connId, nil)
}
s.sendWindow.CloseWindow()
s.receiveWindow.CloseWindow()
return
}
func (s *conn) LocalAddr() net.Addr {
return s.receiveWindow.mux.conn.LocalAddr()
}
func (s *conn) RemoteAddr() net.Addr {
return s.receiveWindow.mux.conn.RemoteAddr()
}
func (s *conn) SetDeadline(t time.Time) error {
_ = s.SetReadDeadline(t)
_ = s.SetWriteDeadline(t)
return nil
}
func (s *conn) SetReadDeadline(t time.Time) error {
s.receiveWindow.SetTimeOut(t)
return nil
}
func (s *conn) SetWriteDeadline(t time.Time) error {
s.sendWindow.SetTimeOut(t)
return nil
}
type window struct {
maxSizeDone uint64
// 64bit alignment
// maxSizeDone contains 4 parts
// 1 31 1 31
// wait maxSize useless done
// wait zero means false, one means true
off uint32
closeOp bool
closeOpCh chan struct{}
mux *Mux
}
const windowBits = 31
const waitBits = dequeueBits + windowBits
const mask1 = 1
const mask31 = 1<<windowBits - 1
func (Self *window) unpack(ptrs uint64) (maxSize, done uint32, wait bool) {
maxSize = uint32((ptrs >> dequeueBits) & mask31)
done = uint32(ptrs & mask31)
if ((ptrs >> waitBits) & mask1) == 1 {
wait = true
return
}
return
}
func (Self *window) pack(maxSize, done uint32, wait bool) uint64 {
if wait {
return (uint64(1)<<waitBits |
uint64(maxSize&mask31)<<dequeueBits) |
uint64(done&mask31)
}
return (uint64(0)<<waitBits |
uint64(maxSize&mask31)<<dequeueBits) |
uint64(done&mask31)
}
func (Self *window) New() {
Self.closeOpCh = make(chan struct{}, 2)
}
func (Self *window) CloseWindow() {
if !Self.closeOp {
Self.closeOp = true
Self.closeOpCh <- struct{}{}
Self.closeOpCh <- struct{}{}
}
}
type receiveWindow struct {
window
bufQueue *receiveWindowQueue
element *listElement
count int8
bw *writeBandwidth
once sync.Once
// receive window send the current max size and read size to send window
// means done size actually store the size receive window has read
}
func (Self *receiveWindow) New(mux *Mux) {
// initial a window for receive
Self.bufQueue = newReceiveWindowQueue()
Self.element = listEle.Get()
Self.maxSizeDone = Self.pack(maximumSegmentSize*30, 0, false)
Self.mux = mux
Self.window.New()
Self.bw = newWriteBandwidth()
}
func (Self *receiveWindow) remainingSize(maxSize uint32, delta uint16) (n uint32) {
// receive window remaining
l := int64(maxSize) - int64(Self.bufQueue.Len())
l -= int64(delta)
if l > 0 {
n = uint32(l)
}
return
}
func (Self *receiveWindow) calcSize() {
// calculating maximum receive window size
if Self.count == 0 {
muxBw := Self.mux.bw.Get()
connBw := Self.bw.Get()
latency := math.Float64frombits(atomic.LoadUint64(&Self.mux.latency))
var n uint32
if connBw > 0 && muxBw > 0 {
if connBw > muxBw {
connBw = muxBw
Self.bw.GrowRatio()
}
n = uint32(latency * (muxBw + connBw))
}
if n < maximumSegmentSize*30 {
n = maximumSegmentSize * 30
}
if n < uint32(float64(maximumSegmentSize*3000)*latency) {
// latency gain
// if there are some latency more than 10ms will trigger this gain
// network pipeline need fill more data that we can measure the max bandwidth
n = uint32(float64(maximumSegmentSize*3000) * latency)
}
for {
ptrs := atomic.LoadUint64(&Self.maxSizeDone)
size, read, wait := Self.unpack(ptrs)
rem := Self.remainingSize(size, 0)
ra := float64(rem) / float64(size)
if ra > 0.8 {
// low fill window gain
// if receive window keep low fill, maybe pipeline fill the data, we need a gain
// less than 20% fill, gain will trigger
n = uint32(float64(n) * 1.5625 * ra * ra)
}
if n < size/2 {
n = size / 2
// half reduce
}
// set the minimal size
if n > 2*size {
if size == maximumSegmentSize*30 {
// we give more ratio when the initial window size, to reduce the time window grow up
if n > size*6 {
n = size * 6
}
} else {
n = 2 * size
// twice grow
}
}
if connBw > 0 && muxBw > 0 {
limit := uint32(maximumWindowSize * (connBw / (muxBw + connBw)))
if n > limit {
log.Println("window too large, calculated:", n, "limit:", limit, connBw, muxBw)
n = limit
}
}
// set the maximum size
if atomic.CompareAndSwapUint64(&Self.maxSizeDone, ptrs, Self.pack(n, read, wait)) {
// only change the maxSize
break
}
}
Self.count = -10
}
Self.count += 1
return
}
func (Self *receiveWindow) Write(buf []byte, l uint16, part bool, id int32) (err error) {
if Self.closeOp {
return errors.New("conn.receiveWindow: write on closed window")
}
element, err := newListElement(buf, l, part)
if err != nil {
return
}
Self.calcSize() // calculate the max window size
var wait bool
var maxSize, read uint32
start:
ptrs := atomic.LoadUint64(&Self.maxSizeDone)
maxSize, read, wait = Self.unpack(ptrs)
remain := Self.remainingSize(maxSize, l)
// calculate the remaining window size now, plus the element we will push
if remain == 0 && !wait {
wait = true
if !atomic.CompareAndSwapUint64(&Self.maxSizeDone, ptrs, Self.pack(maxSize, read, wait)) {
// only change the wait status, not send the read size
goto start
// another goroutine change the status, make sure shall we need wait
}
} else if !wait {
if !atomic.CompareAndSwapUint64(&Self.maxSizeDone, ptrs, Self.pack(maxSize, 0, wait)) {
// reset read size here, and send the read size directly
goto start
// another goroutine change the status, make sure shall we need wait
}
} // maybe there are still some data received even if window is full, just keep the wait status
// and push into queue. when receive window read enough, send window will be acknowledged.
Self.bufQueue.Push(element)
// status check finish, now we can push the element into the queue
if !wait {
Self.mux.sendInfo(muxMsgSendOk, id, Self.pack(maxSize, read, false))
// send the current status to send window
}
return nil
}
func (Self *receiveWindow) Read(p []byte, id int32) (n int, err error) {
if Self.closeOp {
return 0, io.EOF // receive close signal, returns eof
}
Self.bw.StartRead()
n, err = Self.readFromQueue(p, id)
Self.bw.SetCopySize(uint16(n))
return
}
func (Self *receiveWindow) readFromQueue(p []byte, id int32) (n int, err error) {
pOff := 0
l := 0
copyData:
if Self.off == uint32(Self.element.L) {
// on the first Read method invoked, Self.off and Self.element.l
// both zero value
listEle.Put(Self.element)
if Self.closeOp {
return 0, io.EOF
}
Self.element, err = Self.bufQueue.Pop()
// if the queue is empty, Pop method will wait until one element push
// into the queue successful, or timeout.
// timer start on timeout parameter is set up
Self.off = 0
if err != nil {
Self.CloseWindow() // also close the window, to avoid read twice
return // queue receive stop or time out, break the loop and return
}
}
l = copy(p[pOff:], Self.element.Buf[Self.off:Self.element.L])
pOff += l
Self.off += uint32(l)
n += l
l = 0
if Self.off == uint32(Self.element.L) {
windowBuff.Put(Self.element.Buf)
Self.sendStatus(id, Self.element.L)
// check the window full status
}
if pOff < len(p) && Self.element.Part {
// element is a part of the segments, trying to fill up buf p
goto copyData
}
return // buf p is full or all of segments in buf, return
}
func (Self *receiveWindow) sendStatus(id int32, l uint16) {
var maxSize, read uint32
var wait bool
for {
ptrs := atomic.LoadUint64(&Self.maxSizeDone)
maxSize, read, wait = Self.unpack(ptrs)
if read <= (read+uint32(l))&mask31 {
read += uint32(l)
remain := Self.remainingSize(maxSize, 0)
if wait && remain > 0 || read >= maxSize/2 || remain == maxSize {
if atomic.CompareAndSwapUint64(&Self.maxSizeDone, ptrs, Self.pack(maxSize, 0, false)) {
// now we get the current window status success
// receive window free up some space we need acknowledge send window, also reset the read size
// still having a condition that receive window is empty and not send the status to send window
// so send the status here
Self.mux.sendInfo(muxMsgSendOk, id, Self.pack(maxSize, read, false))
break
}
} else {
if atomic.CompareAndSwapUint64(&Self.maxSizeDone, ptrs, Self.pack(maxSize, read, wait)) {
// receive window not into the wait status, or still not having any space now,
// just change the read size
break
}
}
} else {
//overflow
if atomic.CompareAndSwapUint64(&Self.maxSizeDone, ptrs, Self.pack(maxSize, uint32(l), wait)) {
// reset to l
Self.mux.sendInfo(muxMsgSendOk, id, Self.pack(maxSize, read, false))
break
}
}
runtime.Gosched()
// another goroutine change remaining or wait status, make sure
}
return
}
func (Self *receiveWindow) SetTimeOut(t time.Time) {
// waiting for FIFO queue Pop method
Self.bufQueue.SetTimeOut(t)
}
func (Self *receiveWindow) Stop() {
// queue has no more data to push, so unblock pop method
Self.once.Do(Self.bufQueue.Stop)
}
func (Self *receiveWindow) CloseWindow() {
Self.window.CloseWindow()
Self.Stop()
Self.release()
}
func (Self *receiveWindow) release() {
//if Self.element != nil {
// if Self.element.Buf != nil {
// common.WindowBuff.Put(Self.element.Buf)
// }
// common.ListElementPool.Put(Self.element)
//}
for {
ele := Self.bufQueue.TryPop()
if ele == nil {
return
}
if ele.Buf != nil {
windowBuff.Put(ele.Buf)
}
listEle.Put(ele)
} // release resource
}
type sendWindow struct {
window
buf []byte
setSizeCh chan struct{}
timeout time.Time
// send window receive the receive window max size and read size
// done size store the size send window has send, send and read will be totally equal
// so send minus read, send window can get the current window size remaining
}
func (Self *sendWindow) New(mux *Mux) {
Self.setSizeCh = make(chan struct{})
Self.maxSizeDone = Self.pack(maximumSegmentSize*30, 0, false)
Self.mux = mux
Self.window.New()
}
func (Self *sendWindow) SetSendBuf(buf []byte) {
// send window buff from conn write method, set it to send window
Self.buf = buf
Self.off = 0
}
func (Self *sendWindow) remainingSize(maxSize, send uint32) uint32 {
l := int64(maxSize&mask31) - int64(send&mask31)
if l > 0 {
return uint32(l)
}
return 0
}
func (Self *sendWindow) SetSize(currentMaxSizeDone uint64) (closed bool) {
// set the window size from receive window
defer func() {
if recover() != nil {
closed = true
}
}()
if Self.closeOp {
close(Self.setSizeCh)
return true
}
var maxsize, send uint32
var wait, newWait bool
currentMaxSize, read, _ := Self.unpack(currentMaxSizeDone)
for {
ptrs := atomic.LoadUint64(&Self.maxSizeDone)
maxsize, send, wait = Self.unpack(ptrs)
if read > send {
log.Println("window read > send: max size:", currentMaxSize, "read:", read, "send", send)
return
}
if read == 0 && currentMaxSize == maxsize {
return
}
send -= read
remain := Self.remainingSize(currentMaxSize, send)
if remain == 0 && wait {
// just keep the wait status
newWait = true
}
// remain > 0, change wait to false. or remain == 0, wait is false, just keep it
if atomic.CompareAndSwapUint64(&Self.maxSizeDone, ptrs, Self.pack(currentMaxSize, send, newWait)) {
//log.Printf("currentMaxSize:%d read:%d send:%d", currentMaxSize, read, send)
break
}
// anther goroutine change wait status or window size
}
if wait && !newWait {
// send window into the wait status, need notice the channel
Self.allow()
}
// send window not into the wait status, so just do slide
return false
}
func (Self *sendWindow) allow() {
select {
case Self.setSizeCh <- struct{}{}:
return
case <-Self.closeOpCh:
close(Self.setSizeCh)
return
}
}
func (Self *sendWindow) sent(sentSize uint32) {
var maxSie, send uint32
var wait bool
for {
ptrs := atomic.LoadUint64(&Self.maxSizeDone)
maxSie, send, wait = Self.unpack(ptrs)
if (send+sentSize)&mask31 < send {
// overflow
runtime.Gosched()
continue
}
if atomic.CompareAndSwapUint64(&Self.maxSizeDone, ptrs, Self.pack(maxSie, send+sentSize, wait)) {
// set the send size
break
}
}
}
func (Self *sendWindow) WriteTo() (p []byte, sendSize uint32, part bool, err error) {
// returns buf segments, return only one segments, need a loop outside
// until err = io.EOF
if Self.closeOp {
return nil, 0, false, errors.New("conn.writeWindow: window closed")
}
if Self.off == uint32(len(Self.buf)) {
return nil, 0, false, io.EOF
// send window buff is drain, return eof and get another one
}
var maxSize, send uint32
start:
ptrs := atomic.LoadUint64(&Self.maxSizeDone)
maxSize, send, _ = Self.unpack(ptrs)
remain := Self.remainingSize(maxSize, send)
if remain == 0 {
if !atomic.CompareAndSwapUint64(&Self.maxSizeDone, ptrs, Self.pack(maxSize, send, true)) {
// just change the status wait status
goto start // another goroutine change the window, try again
}
// into the wait status
err = Self.waitReceiveWindow()
if err != nil {
return nil, 0, false, err
}
goto start
}
// there are still remaining window
if len(Self.buf[Self.off:]) > maximumSegmentSize {
sendSize = maximumSegmentSize
} else {
sendSize = uint32(len(Self.buf[Self.off:]))
}
if remain < sendSize {
// usable window size is small than
// window MAXIMUM_SEGMENT_SIZE or send buf left
sendSize = remain
}
if sendSize < uint32(len(Self.buf[Self.off:])) {
part = true
}
p = Self.buf[Self.off : sendSize+Self.off]
Self.off += sendSize
Self.sent(sendSize)
return
}
func (Self *sendWindow) waitReceiveWindow() (err error) {
t := Self.timeout.Sub(time.Now())
if t < 0 { // not set the timeout, wait for it as long as connection close
select {
case _, ok := <-Self.setSizeCh:
if !ok {
return errors.New("conn.writeWindow: window closed")
}
return nil
case <-Self.closeOpCh:
return errors.New("conn.writeWindow: window closed")
}
}
timer := time.NewTimer(t)
defer timer.Stop()
// waiting for receive usable window size, or timeout
select {
case _, ok := <-Self.setSizeCh:
if !ok {
return errors.New("conn.writeWindow: window closed")
}
return nil
case <-timer.C:
return errors.New("conn.writeWindow: write to time out")
case <-Self.closeOpCh:
return errors.New("conn.writeWindow: window closed")
}
}
func (Self *sendWindow) WriteFull(buf []byte, id int32) (n int, err error) {
Self.SetSendBuf(buf) // set the buf to send window
var bufSeg []byte
var part bool
var l uint32
for {
bufSeg, l, part, err = Self.WriteTo()
// get the buf segments from send window
if bufSeg == nil && part == false && err == io.EOF {
// send window is drain, break the loop
err = nil
break
}
if err != nil {
break
}
n += int(l)
l = 0
if part {
Self.mux.sendInfo(muxNewMsgPart, id, bufSeg)
} else {
Self.mux.sendInfo(muxNewMsg, id, bufSeg)
}
// send to other side, not send nil data to other side
}
return
}
func (Self *sendWindow) SetTimeOut(t time.Time) {
// waiting for receive a receive window size
Self.timeout = t
}
type writeBandwidth struct {
writeBW uint64 // store in bits, but it's float64
readEnd time.Time
duration float64
bufLength uint32
ratio uint32
}
const writeCalcThreshold uint32 = 5 * 1024 * 1024
func newWriteBandwidth() *writeBandwidth {
return &writeBandwidth{ratio: 1}
}
func (Self *writeBandwidth) StartRead() {
if Self.readEnd.IsZero() {
Self.readEnd = time.Now()
}
Self.duration += time.Now().Sub(Self.readEnd).Seconds()
if Self.bufLength >= writeCalcThreshold*atomic.LoadUint32(&Self.ratio) {
Self.calcBandWidth()
}
}
func (Self *writeBandwidth) SetCopySize(n uint16) {
Self.bufLength += uint32(n)
Self.endRead()
}
func (Self *writeBandwidth) endRead() {
Self.readEnd = time.Now()
}
func (Self *writeBandwidth) calcBandWidth() {
atomic.StoreUint64(&Self.writeBW, math.Float64bits(float64(Self.bufLength)/Self.duration))
Self.bufLength = 0
Self.duration = 0
}
func (Self *writeBandwidth) Get() (bw float64) {
// The zero value, 0 for numeric types
bw = math.Float64frombits(atomic.LoadUint64(&Self.writeBW))
if bw <= 0 {
bw = 0
}
return
}
func (Self *writeBandwidth) GrowRatio() {
atomic.AddUint32(&Self.ratio, 1)
}