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|
package rudp
import (
"bytes"
"errors"
"fmt"
"io"
"net"
"sync"
"sync/atomic"
"time"
)
var ErrPktTooBig = errors.New("can't send pkt: too big")
// A TooBigChError reports a Channel greater than or equal to ChannelCount.
type TooBigChError Channel
func (e TooBigChError) Error() string {
return fmt.Sprintf("channel >= ChannelCount (%d): %d", ChannelCount, e)
}
// Send sends a Pkt to the Conn.
// Ack is closed when the packet is acknowledged.
// Ack is nil if pkt.Unrel is true or err != nil.
func (c *Conn) Send(pkt Pkt) (ack <-chan struct{}, err error) {
if pkt.Channel >= ChannelCount {
return nil, TooBigChError(pkt.Channel)
}
var e error
send := c.sendRaw(func(buf []byte) int {
buf[0] = uint8(rawOrig)
nn := 1
for nn < len(buf) {
n, err := pkt.Read(buf[nn:])
nn += n
if err != nil {
e = err
return nn
}
}
if _, e = pkt.Read(nil); e != nil {
return nn
}
pkt.Reader = io.MultiReader(
bytes.NewReader([]byte(buf[1:nn])),
pkt.Reader,
)
return nn
}, pkt.PktInfo)
if e != nil {
if e == io.EOF {
return send()
}
return nil, e
}
var (
sn seqnum
i uint16
sends []func() (<-chan struct{}, error)
)
for {
var (
b []byte
e error
)
send := c.sendRaw(func(buf []byte) int {
buf[0] = uint8(rawSplit)
n, err := io.ReadFull(pkt, buf[7:])
if err != nil && err != io.ErrUnexpectedEOF {
e = err
return 0
}
be.PutUint16(buf[5:7], i)
if i++; i == 0 {
e = ErrPktTooBig
return 0
}
b = buf
return 7 + n
}, pkt.PktInfo)
if e != nil {
if e == io.EOF {
break
}
return nil, e
}
sends = append(sends, func() (<-chan struct{}, error) {
be.PutUint16(b[1:3], uint16(sn))
be.PutUint16(b[3:5], i)
return send()
})
}
ch := &c.chans[pkt.Channel]
ch.outSplitMu.Lock()
sn = ch.outSplitSN
ch.outSplitSN++
ch.outSplitMu.Unlock()
var wg sync.WaitGroup
for _, send := range sends {
ack, err := send()
if err != nil {
return nil, err
}
if !pkt.Unrel {
wg.Add(1)
go func() {
<-ack
wg.Done()
}()
}
}
if !pkt.Unrel {
ack := make(chan struct{})
go func() {
wg.Wait()
close(ack)
}()
return ack, nil
}
return nil, nil
}
func (c *Conn) sendRaw(read func([]byte) int, pi PktInfo) func() (<-chan struct{}, error) {
if pi.Unrel {
buf := make([]byte, maxUDPPktSize)
be.PutUint32(buf[0:4], protoID)
c.mu.RLock()
be.PutUint16(buf[4:6], uint16(c.remoteID))
c.mu.RUnlock()
buf[6] = uint8(pi.Channel)
buf = buf[:7+read(buf[7:])]
return func() (<-chan struct{}, error) {
if _, err := c.udpConn.Write(buf); err != nil {
c.close(err)
return nil, net.ErrClosed
}
c.ping.Reset(PingTimeout)
if atomic.LoadUint32(&c.closing) == 1 {
c.ping.Stop()
}
return nil, nil
}
}
pi.Unrel = true
var snBuf []byte
send := c.sendRaw(func(buf []byte) int {
buf[0] = uint8(rawRel)
snBuf = buf[1:3]
return 3 + read(buf[3:])
}, pi)
return func() (<-chan struct{}, error) {
ch := &c.chans[pi.Channel]
ch.outRelMu.Lock()
defer ch.outRelMu.Unlock()
sn := ch.outRelSN
be.PutUint16(snBuf, uint16(sn))
for ; sn-ch.outRelWin >= 0x8000; ch.outRelWin++ {
if ack, ok := ch.ackChans.Load(ch.outRelWin); ok {
select {
case <-ack.(chan struct{}):
case <-c.Closed():
}
}
}
ack := make(chan struct{})
ch.ackChans.Store(sn, ack)
if _, err := send(); err != nil {
if ack, ok := ch.ackChans.LoadAndDelete(sn); ok {
close(ack.(chan struct{}))
}
return nil, err
}
ch.outRelSN++
go func() {
t := time.NewTimer(500 * time.Millisecond)
defer t.Stop()
for {
select {
case <-ack:
return
case <-t.C:
send()
t.Reset(500 * time.Millisecond)
case <-c.Closed():
return
}
}
}()
return ack, nil
}
}
|
