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|
package rudp
import (
"errors"
"fmt"
"net"
"sync"
"time"
)
const (
// ConnTimeout is the amount of time after no packets being received
// from a Peer that it is automatically disconnected.
ConnTimeout = 30 * time.Second
// ConnTimeout is the amount of time after no packets being sent
// to a Peer that a CtlPing is automatically sent to prevent timeout.
PingTimeout = 5 * time.Second
)
// A Peer is a connection to a client or server.
type Peer struct {
pc net.PacketConn
addr net.Addr
conn net.Conn
disco chan struct{} // close-only
id PeerID
pkts chan Pkt
errs chan error // don't close
timedOut chan struct{} // close-only
chans [ChannelCount]pktchan // read/write
mu sync.RWMutex
idOfPeer PeerID
timeout *time.Timer
ping *time.Ticker
}
// Conn returns the net.PacketConn used to communicate with the Peer.
func (p *Peer) Conn() net.PacketConn { return p.pc }
// Addr returns the address of the Peer.
func (p *Peer) Addr() net.Addr { return p.addr }
// Disco returns a channel that is closed when the Peer is closed.
func (p *Peer) Disco() <-chan struct{} { return p.disco }
// ID returns the ID of the Peer.
func (p *Peer) ID() PeerID { return p.id }
// IsSrv reports whether the Peer is a server.
func (p *Peer) IsSrv() bool {
return p.ID() == PeerIDSrv
}
// TimedOut reports whether the Peer has timed out.
func (p *Peer) TimedOut() bool {
select {
case <-p.timedOut:
return true
default:
return false
}
}
type inSplit struct {
chunks [][]byte
size, got int
}
type pktchan struct {
// Only accessed by Peer.processRawPkt.
inSplit *[65536]*inSplit
inRel *[65536][]byte
inRelSN seqnum
ackChans sync.Map // map[seqnum]chan struct{}
outSplitMu sync.Mutex
outSplitSN seqnum
outRelMu sync.Mutex
outRelSN seqnum
outRelWin seqnum
}
// Recv recieves a packet from the Peer.
// You should keep calling this until it returns net.ErrClosed
// so it doesn't leak a goroutine.
func (p *Peer) Recv() (Pkt, error) {
select {
case pkt, ok := <-p.pkts:
if !ok {
select {
case err := <-p.errs:
return Pkt{}, err
default:
return Pkt{}, net.ErrClosed
}
}
return pkt, nil
case err := <-p.errs:
return Pkt{}, err
}
}
// Close closes the Peer but does not send a disconnect packet.
func (p *Peer) Close() error {
p.mu.Lock()
defer p.mu.Unlock()
select {
case <-p.Disco():
return net.ErrClosed
default:
}
p.timeout.Stop()
p.timeout = nil
p.ping.Stop()
p.ping = nil
close(p.disco)
return nil
}
func newPeer(pc net.PacketConn, addr net.Addr, id, idOfPeer PeerID) *Peer {
p := &Peer{
pc: pc,
addr: addr,
id: id,
idOfPeer: idOfPeer,
pkts: make(chan Pkt),
disco: make(chan struct{}),
errs: make(chan error),
}
if conn, ok := pc.(net.Conn); ok && conn.RemoteAddr() != nil {
p.conn = conn
}
for i := range p.chans {
p.chans[i] = pktchan{
inSplit: new([65536]*inSplit),
inRel: new([65536][]byte),
inRelSN: seqnumInit,
outSplitSN: seqnumInit,
outRelSN: seqnumInit,
outRelWin: seqnumInit,
}
}
p.timedOut = make(chan struct{})
p.timeout = time.AfterFunc(ConnTimeout, func() {
close(p.timedOut)
p.SendDisco(0, true)
p.Close()
})
p.ping = time.NewTicker(PingTimeout)
go p.sendPings(p.ping.C)
return p
}
func (p *Peer) sendPings(ping <-chan time.Time) {
pkt := rawPkt{Data: []byte{uint8(rawTypeCtl), uint8(ctlPing)}}
for {
select {
case <-ping:
if _, err := p.sendRaw(pkt); err != nil {
if errors.Is(err, net.ErrClosed) {
return
}
p.errs <- fmt.Errorf("can't send ping: %w", err)
}
case <-p.Disco():
return
}
}
}
// Connect connects to addr using pc
// and closes pc when the returned *Peer disconnects.
func Connect(pc net.PacketConn, addr net.Addr) *Peer {
srv := newPeer(pc, addr, PeerIDSrv, PeerIDNil)
pkts := make(chan netPkt)
go readNetPkts(pc, pkts, srv.errs)
go srv.processNetPkts(pkts)
go func() {
<-srv.Disco()
pc.Close()
}()
return srv
}
|
