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|
package rudp
import (
"errors"
"fmt"
"io"
"net"
)
// A PktError is an error that occured while processing a packet.
type PktError struct {
Type string // "net", "raw" or "rel".
Data []byte
Err error
}
func (e PktError) Error() string {
return fmt.Sprintf("error processing %s pkt: %x: %v", e.Type, e.Data, e.Err)
}
func (e PktError) Unwrap() error { return e.Err }
func (p *Peer) processNetPkts(pkts <-chan netPkt) {
for pkt := range pkts {
if err := p.processNetPkt(pkt); err != nil {
p.errs <- PktError{"net", pkt.Data, err}
}
}
close(p.pkts)
}
// A TrailingDataError reports a packet with trailing data,
// it doesn't stop a packet from being processed.
type TrailingDataError []byte
func (e TrailingDataError) Error() string {
return fmt.Sprintf("trailing data: %x", []byte(e))
}
func (p *Peer) processNetPkt(pkt netPkt) (err error) {
if pkt.SrcAddr.String() != p.Addr().String() {
return fmt.Errorf("got pkt from wrong addr: %s", p.Addr().String())
}
if len(pkt.Data) < MtHdrSize {
return io.ErrUnexpectedEOF
}
if id := be.Uint32(pkt.Data[0:4]); id != protoID {
return fmt.Errorf("unsupported protocol id: 0x%08x", id)
}
// src PeerID at pkt.Data[4:6]
chno := pkt.Data[6]
if chno >= ChannelCount {
return fmt.Errorf("invalid channel number: %d: >= ChannelCount", chno)
}
p.mu.RLock()
if p.timeout != nil {
p.timeout.Reset(ConnTimeout)
}
p.mu.RUnlock()
rpkt := rawPkt{
Data: pkt.Data[MtHdrSize:],
ChNo: chno,
Unrel: true,
}
if err := p.processRawPkt(rpkt); err != nil {
p.errs <- PktError{"raw", rpkt.Data, err}
}
return nil
}
func (p *Peer) processRawPkt(pkt rawPkt) (err error) {
errWrap := func(format string, a ...interface{}) {
if err != nil {
err = fmt.Errorf(format, append(a, err)...)
}
}
c := &p.chans[pkt.ChNo]
if len(pkt.Data) < 1 {
return fmt.Errorf("can't read pkt type: %w", io.ErrUnexpectedEOF)
}
switch t := rawType(pkt.Data[0]); t {
case rawTypeCtl:
defer errWrap("ctl: %w")
if len(pkt.Data) < 1+1 {
return fmt.Errorf("can't read type: %w", io.ErrUnexpectedEOF)
}
switch ct := ctlType(pkt.Data[1]); ct {
case ctlAck:
defer errWrap("ack: %w")
if len(pkt.Data) < 1+1+2 {
return io.ErrUnexpectedEOF
}
sn := seqnum(be.Uint16(pkt.Data[2:4]))
if ack, ok := c.ackChans.LoadAndDelete(sn); ok {
close(ack.(chan struct{}))
}
if len(pkt.Data) > 1+1+2 {
return TrailingDataError(pkt.Data[1+1+2:])
}
case ctlSetPeerID:
defer errWrap("set peer id: %w")
if len(pkt.Data) < 1+1+2 {
return io.ErrUnexpectedEOF
}
// Ensure no concurrent senders while peer id changes.
p.mu.Lock()
if p.idOfPeer != PeerIDNil {
return errors.New("peer id already set")
}
p.idOfPeer = PeerID(be.Uint16(pkt.Data[2:4]))
p.mu.Unlock()
if len(pkt.Data) > 1+1+2 {
return TrailingDataError(pkt.Data[1+1+2:])
}
case ctlPing:
defer errWrap("ping: %w")
if len(pkt.Data) > 1+1 {
return TrailingDataError(pkt.Data[1+1:])
}
case ctlDisco:
defer errWrap("disco: %w")
p.Close()
if len(pkt.Data) > 1+1 {
return TrailingDataError(pkt.Data[1+1:])
}
default:
return fmt.Errorf("unsupported ctl type: %d", ct)
}
case rawTypeOrig:
p.pkts <- Pkt{
Data: pkt.Data[1:],
ChNo: pkt.ChNo,
Unrel: pkt.Unrel,
}
case rawTypeSplit:
defer errWrap("split: %w")
if len(pkt.Data) < 1+2+2+2 {
return io.ErrUnexpectedEOF
}
sn := seqnum(be.Uint16(pkt.Data[1:3]))
count := be.Uint16(pkt.Data[3:5])
i := be.Uint16(pkt.Data[5:7])
if i >= count {
return nil
}
splits := p.chans[pkt.ChNo].inSplit
// Delete old incomplete split packets
// so new ones don't get corrupted.
splits[sn-0x8000] = nil
if splits[sn] == nil {
splits[sn] = &inSplit{chunks: make([][]byte, count)}
}
s := splits[sn]
if int(count) != len(s.chunks) {
return fmt.Errorf("chunk count changed on split packet: %d", sn)
}
s.chunks[i] = pkt.Data[7:]
s.size += len(s.chunks[i])
s.got++
if s.got == len(s.chunks) {
data := make([]byte, 0, s.size)
for _, chunk := range s.chunks {
data = append(data, chunk...)
}
p.pkts <- Pkt{
Data: data,
ChNo: pkt.ChNo,
Unrel: pkt.Unrel,
}
splits[sn] = nil
}
case rawTypeRel:
defer errWrap("rel: %w")
if len(pkt.Data) < 1+2 {
return io.ErrUnexpectedEOF
}
sn := seqnum(be.Uint16(pkt.Data[1:3]))
ack := make([]byte, 1+1+2)
ack[0] = uint8(rawTypeCtl)
ack[1] = uint8(ctlAck)
be.PutUint16(ack[2:4], uint16(sn))
if _, err := p.sendRaw(rawPkt{
Data: ack,
ChNo: pkt.ChNo,
Unrel: true,
}); err != nil {
if errors.Is(err, net.ErrClosed) {
return nil
}
return fmt.Errorf("can't ack %d: %w", sn, err)
}
if sn-c.inRelSN >= 0x8000 {
return nil // Already received.
}
c.inRel[sn] = pkt.Data[3:]
for ; c.inRel[c.inRelSN] != nil; c.inRelSN++ {
rpkt := rawPkt{
Data: c.inRel[c.inRelSN],
ChNo: pkt.ChNo,
Unrel: false,
}
c.inRel[c.inRelSN] = nil
if err := p.processRawPkt(rpkt); err != nil {
p.errs <- PktError{"rel", rpkt.Data, err}
}
}
default:
return fmt.Errorf("unsupported pkt type: %d", t)
}
return nil
}
|
