func (d *UDPClient) sendAnnouncement(remote net.Addr, conn *net.UDPConn) bool {
if debug {
l.Debugf("discover %s: broadcast: Sending self announcement to %v", d.url, remote)
}
ann := d.announcer.Announcement()
pkt, err := ann.MarshalXDR()
if err != nil {
return false
}
myID := protocol.DeviceIDFromBytes(ann.This.ID)
_, err = conn.WriteTo(pkt, remote)
if err != nil {
if debug {
l.Debugf("discover %s: broadcast: Failed to send self announcement: %s", d.url, err)
}
return false
}
// Verify that the announce server responds positively for our device ID
time.Sleep(1 * time.Second)
ann, err = d.Lookup(myID)
if err != nil && debug {
l.Debugf("discover %s: broadcast: Self-lookup failed: %v", d.url, err)
} else if debug {
l.Debugf("discover %s: broadcast: Self-lookup returned: %v", d.url, ann.This.Addresses)
}
return len(ann.This.Addresses) > 0
}
func (d *Discoverer) recvAnnouncements(b beacon.Interface) {
for {
buf, addr := b.Recv()
var pkt Announce
err := pkt.UnmarshalXDR(buf)
if err != nil && err != io.EOF {
if debug {
l.Debugf("discover: Failed to unmarshal local announcement from %s:\n%s", addr, hex.Dump(buf))
}
continue
}
if debug {
l.Debugf("discover: Received local announcement from %s for %s", addr, protocol.DeviceIDFromBytes(pkt.This.ID))
}
var newDevice bool
if bytes.Compare(pkt.This.ID, d.myID[:]) != 0 {
newDevice = d.registerDevice(addr, pkt.This)
}
if newDevice {
select {
case d.forcedBcastTick <- time.Now():
}
}
}
}
func (d *UDPClient) Start(uri *url.URL, pkt *Announce) error {
d.url = uri
d.id = protocol.DeviceIDFromBytes(pkt.This.ID)
d.stop = make(chan struct{})
params := uri.Query()
// The address must not have a port, as otherwise both announce and lookup
// sockets would try to bind to the same port.
addr, err := net.ResolveUDPAddr(d.url.Scheme, params.Get("listenaddress")+":0")
if err != nil {
return err
}
d.listenAddress = addr
broadcastSeconds, err := strconv.ParseUint(params.Get("broadcast"), 0, 0)
if err != nil {
d.globalBroadcastInterval = DefaultGlobalBroadcastInterval
} else {
d.globalBroadcastInterval = time.Duration(broadcastSeconds) * time.Second
}
retrySeconds, err := strconv.ParseUint(params.Get("retry"), 0, 0)
if err != nil {
d.errorRetryInterval = DefaultErrorRetryInternval
} else {
d.errorRetryInterval = time.Duration(retrySeconds) * time.Second
}
d.wg.Add(1)
go d.broadcast(pkt.MustMarshalXDR())
return nil
}
func ldbAvailability(db *leveldb.DB, folder, file []byte) []protocol.DeviceID {
k := globalKey(folder, file)
bs, err := db.Get(k, nil)
if err == leveldb.ErrNotFound {
return nil
}
if err != nil {
panic(err)
}
var vl versionList
err = vl.UnmarshalXDR(bs)
if err != nil {
panic(err)
}
var devices []protocol.DeviceID
for _, v := range vl.versions {
if v.version != vl.versions[0].version {
break
}
n := protocol.DeviceIDFromBytes(v.device)
devices = append(devices, n)
}
return devices
}
func ldbReplaceWithDelete(db *leveldb.DB, folder, device []byte, fs []protocol.FileInfo) int64 {
return ldbGenericReplace(db, folder, device, fs, func(db dbReader, batch dbWriter, folder, device, name []byte, dbi iterator.Iterator) int64 {
var tf FileInfoTruncated
err := tf.UnmarshalXDR(dbi.Value())
if err != nil {
panic(err)
}
if !tf.IsDeleted() {
if debugDB {
l.Debugf("mark deleted; folder=%q device=%v name=%q", folder, protocol.DeviceIDFromBytes(device), name)
}
ts := clock(tf.LocalVersion)
f := protocol.FileInfo{
Name: tf.Name,
Version: lamport.Default.Tick(tf.Version),
LocalVersion: ts,
Flags: tf.Flags | protocol.FlagDeleted,
Modified: tf.Modified,
}
bs, _ := f.MarshalXDR()
if debugDB {
l.Debugf("batch.Put %p %x", batch, dbi.Key())
}
batch.Put(dbi.Key(), bs)
ldbUpdateGlobal(db, batch, folder, device, deviceKeyName(dbi.Key()), f.Version)
return ts
}
return 0
})
}
// ldbUpdateGlobal adds this device+version to the version list for the given
// file. If the device is already present in the list, the version is updated.
// If the file does not have an entry in the global list, it is created.
func ldbUpdateGlobal(db dbReader, batch dbWriter, folder, device, file []byte, version protocol.Vector) bool {
if debugDB {
l.Debugf("update global; folder=%q device=%v file=%q version=%d", folder, protocol.DeviceIDFromBytes(device), file, version)
}
gk := globalKey(folder, file)
svl, err := db.Get(gk, nil)
if err != nil && err != leveldb.ErrNotFound {
panic(err)
}
var fl versionList
// Remove the device from the current version list
if svl != nil {
err = fl.UnmarshalXDR(svl)
if err != nil {
panic(err)
}
for i := range fl.versions {
if bytes.Compare(fl.versions[i].device, device) == 0 {
if fl.versions[i].version.Equal(version) {
// No need to do anything
return false
}
fl.versions = append(fl.versions[:i], fl.versions[i+1:]...)
break
}
}
}
nv := fileVersion{
device: device,
version: version,
}
for i := range fl.versions {
// We compare against ConcurrentLesser as well here because we need
// to enforce a consistent ordering of versions even in the case of
// conflicts.
if comp := fl.versions[i].version.Compare(version); comp == protocol.Equal || comp == protocol.Lesser || comp == protocol.ConcurrentLesser {
t := append(fl.versions, fileVersion{})
copy(t[i+1:], t[i:])
t[i] = nv
fl.versions = t
goto done
}
}
fl.versions = append(fl.versions, nv)
done:
if debugDB {
l.Debugf("batch.Put %p %x", batch, gk)
l.Debugf("new global after update: %v", fl)
}
batch.Put(gk, fl.MustMarshalXDR())
return true
}
// ldbUpdateGlobal adds this device+version to the version list for the given
// file. If the device is already present in the list, the version is updated.
// If the file does not have an entry in the global list, it is created.
func ldbUpdateGlobal(db dbReader, batch dbWriter, folder, device, file []byte, version int64) bool {
if debugDB {
l.Debugf("update global; folder=%q device=%v file=%q version=%d", folder, protocol.DeviceIDFromBytes(device), file, version)
}
gk := globalKey(folder, file)
svl, err := db.Get(gk, nil)
if err != nil && err != leveldb.ErrNotFound {
panic(err)
}
var fl versionList
nv := fileVersion{
device: device,
version: version,
}
if svl != nil {
err = fl.UnmarshalXDR(svl)
if err != nil {
panic(err)
}
for i := range fl.versions {
if bytes.Compare(fl.versions[i].device, device) == 0 {
if fl.versions[i].version == version {
// No need to do anything
return false
}
fl.versions = append(fl.versions[:i], fl.versions[i+1:]...)
break
}
}
}
for i := range fl.versions {
if fl.versions[i].version <= version {
t := append(fl.versions, fileVersion{})
copy(t[i+1:], t[i:])
t[i] = nv
fl.versions = t
goto done
}
}
fl.versions = append(fl.versions, nv)
done:
if debugDB {
l.Debugf("batch.Put %p %x", batch, gk)
l.Debugf("new global after update: %v", fl)
}
batch.Put(gk, fl.MustMarshalXDR())
return true
}
func ldbReplace(db *leveldb.DB, folder, device []byte, fs []protocol.FileInfo) int64 {
// TODO: Return the remaining maxLocalVer?
return ldbGenericReplace(db, folder, device, fs, func(db dbReader, batch dbWriter, folder, device, name []byte, dbi iterator.Iterator) int64 {
// Database has a file that we are missing. Remove it.
if debugDB {
l.Debugf("delete; folder=%q device=%v name=%q", folder, protocol.DeviceIDFromBytes(device), name)
}
ldbRemoveFromGlobal(db, batch, folder, device, name)
if debugDB {
l.Debugf("batch.Delete %p %x", batch, dbi.Key())
}
batch.Delete(dbi.Key())
return 0
})
}
func ldbInsert(batch dbWriter, folder, device []byte, file protocol.FileInfo) int64 {
if debugDB {
l.Debugf("insert; folder=%q device=%v %v", folder, protocol.DeviceIDFromBytes(device), file)
}
if file.LocalVersion == 0 {
file.LocalVersion = clock(0)
}
name := []byte(file.Name)
nk := deviceKey(folder, device, name)
if debugDB {
l.Debugf("batch.Put %p %x", batch, nk)
}
batch.Put(nk, file.MustMarshalXDR())
return file.LocalVersion
}
// ldbRemoveFromGlobal removes the device from the global version list for the
// given file. If the version list is empty after this, the file entry is
// removed entirely.
func ldbRemoveFromGlobal(db dbReader, batch dbWriter, folder, device, file []byte) {
if debugDB {
l.Debugf("remove from global; folder=%q device=%v file=%q", folder, protocol.DeviceIDFromBytes(device), file)
}
gk := globalKey(folder, file)
svl, err := db.Get(gk, nil)
if err != nil {
// We might be called to "remove" a global version that doesn't exist
// if the first update for the file is already marked invalid.
return
}
var fl versionList
err = fl.UnmarshalXDR(svl)
if err != nil {
panic(err)
}
for i := range fl.versions {
if bytes.Compare(fl.versions[i].device, device) == 0 {
fl.versions = append(fl.versions[:i], fl.versions[i+1:]...)
break
}
}
if len(fl.versions) == 0 {
if debugDB {
l.Debugf("batch.Delete %p %x", batch, gk)
}
batch.Delete(gk)
} else {
if debugDB {
l.Debugf("batch.Put %p %x", batch, gk)
l.Debugf("new global after remove: %v", fl)
}
batch.Put(gk, fl.MustMarshalXDR())
}
}
func (d *UDPClient) broadcast() {
defer d.wg.Done()
conn, err := net.ListenUDP(d.url.Scheme, d.listenAddress)
for err != nil {
if debug {
l.Debugf("discover %s: broadcast listen: %v; trying again in %v", d.url, err, d.errorRetryInterval)
}
select {
case <-d.stop:
return
case <-time.After(d.errorRetryInterval):
}
conn, err = net.ListenUDP(d.url.Scheme, d.listenAddress)
}
defer conn.Close()
remote, err := net.ResolveUDPAddr(d.url.Scheme, d.url.Host)
for err != nil {
if debug {
l.Debugf("discover %s: broadcast resolve: %v; trying again in %v", d.url, err, d.errorRetryInterval)
}
select {
case <-d.stop:
return
case <-time.After(d.errorRetryInterval):
}
remote, err = net.ResolveUDPAddr(d.url.Scheme, d.url.Host)
}
timer := time.NewTimer(0)
for {
select {
case <-d.stop:
return
case <-timer.C:
var ok bool
if debug {
l.Debugf("discover %s: broadcast: Sending self announcement to %v", d.url, remote)
}
ann := d.announcer.Announcement()
pkt, err := ann.MarshalXDR()
if err != nil {
timer.Reset(d.errorRetryInterval)
continue
}
_, err = conn.WriteTo(pkt, remote)
if err != nil {
if debug {
l.Debugf("discover %s: broadcast: Failed to send self announcement: %s", d.url, err)
}
ok = false
} else {
// Verify that the announce server responds positively for our device ID
time.Sleep(1 * time.Second)
pkt, err := d.Lookup(protocol.DeviceIDFromBytes(ann.This.ID))
if err != nil && debug {
l.Debugf("discover %s: broadcast: Self-lookup failed: %v", d.url, err)
} else if debug {
l.Debugf("discover %s: broadcast: Self-lookup returned: %v", d.url, pkt.This.Addresses)
}
ok = len(pkt.This.Addresses) > 0
}
d.mut.Lock()
d.status = ok
d.mut.Unlock()
if ok {
timer.Reset(d.globalBroadcastInterval)
} else {
timer.Reset(d.errorRetryInterval)
}
}
}
}
func (i SessionInvitation) String() string {
return fmt.Sprintf("%s@%s", syncthingprotocol.DeviceIDFromBytes(i.From), i.AddressString())
}
func ldbWithNeed(db *leveldb.DB, folder, device []byte, truncate bool, fn Iterator) {
runtime.GC()
start := globalKey(folder, nil)
limit := globalKey(folder, []byte{0xff, 0xff, 0xff, 0xff})
snap, err := db.GetSnapshot()
if err != nil {
panic(err)
}
if debugDB {
l.Debugf("created snapshot %p", snap)
}
defer func() {
if debugDB {
l.Debugf("close snapshot %p", snap)
}
snap.Release()
}()
dbi := snap.NewIterator(&util.Range{Start: start, Limit: limit}, nil)
defer dbi.Release()
outer:
for dbi.Next() {
var vl versionList
err := vl.UnmarshalXDR(dbi.Value())
if err != nil {
panic(err)
}
if len(vl.versions) == 0 {
l.Debugln(dbi.Key())
panic("no versions?")
}
have := false // If we have the file, any version
need := false // If we have a lower version of the file
var haveVersion int64
for _, v := range vl.versions {
if bytes.Compare(v.device, device) == 0 {
have = true
haveVersion = v.version
need = v.version < vl.versions[0].version
break
}
}
if need || !have {
name := globalKeyName(dbi.Key())
needVersion := vl.versions[0].version
inner:
for i := range vl.versions {
if vl.versions[i].version != needVersion {
// We haven't found a valid copy of the file with the needed version.
continue outer
}
fk := deviceKey(folder, vl.versions[i].device, name)
if debugDB {
l.Debugf("snap.Get %p %x", snap, fk)
}
bs, err := snap.Get(fk, nil)
if err != nil {
var id protocol.DeviceID
copy(id[:], device)
l.Debugf("device: %v", id)
l.Debugf("need: %v, have: %v", need, have)
l.Debugf("key: %q (%x)", dbi.Key(), dbi.Key())
l.Debugf("vl: %v", vl)
l.Debugf("i: %v", i)
l.Debugf("fk: %q (%x)", fk, fk)
l.Debugf("name: %q (%x)", name, name)
panic(err)
}
gf, err := unmarshalTrunc(bs, truncate)
if err != nil {
panic(err)
}
if gf.IsInvalid() {
// The file is marked invalid for whatever reason, don't use it.
continue inner
}
if gf.IsDeleted() && !have {
// We don't need deleted files that we don't have
continue outer
}
if debugDB {
l.Debugf("need folder=%q device=%v name=%q need=%v have=%v haveV=%d globalV=%d", folder, protocol.DeviceIDFromBytes(device), name, need, have, haveVersion, vl.versions[0].version)
}
if cont := fn(gf); !cont {
return
}
// This file is handled, no need to look further in the version list
continue outer
}
}
}
}
func ldbGenericReplace(db *leveldb.DB, folder, device []byte, fs []protocol.FileInfo, deleteFn deletionHandler) int64 {
runtime.GC()
sort.Sort(fileList(fs)) // sort list on name, same as in the database
start := deviceKey(folder, device, nil) // before all folder/device files
limit := deviceKey(folder, device, []byte{0xff, 0xff, 0xff, 0xff}) // after all folder/device files
batch := new(leveldb.Batch)
if debugDB {
l.Debugf("new batch %p", batch)
}
snap, err := db.GetSnapshot()
if err != nil {
panic(err)
}
if debugDB {
l.Debugf("created snapshot %p", snap)
}
defer func() {
if debugDB {
l.Debugf("close snapshot %p", snap)
}
snap.Release()
}()
dbi := snap.NewIterator(&util.Range{Start: start, Limit: limit}, nil)
defer dbi.Release()
moreDb := dbi.Next()
fsi := 0
var maxLocalVer int64
for {
var newName, oldName []byte
moreFs := fsi < len(fs)
if !moreDb && !moreFs {
break
}
if moreFs {
newName = []byte(fs[fsi].Name)
}
if moreDb {
oldName = deviceKeyName(dbi.Key())
}
cmp := bytes.Compare(newName, oldName)
if debugDB {
l.Debugf("generic replace; folder=%q device=%v moreFs=%v moreDb=%v cmp=%d newName=%q oldName=%q", folder, protocol.DeviceIDFromBytes(device), moreFs, moreDb, cmp, newName, oldName)
}
switch {
case moreFs && (!moreDb || cmp == -1):
if debugDB {
l.Debugln("generic replace; missing - insert")
}
// Database is missing this file. Insert it.
if lv := ldbInsert(batch, folder, device, fs[fsi]); lv > maxLocalVer {
maxLocalVer = lv
}
if fs[fsi].IsInvalid() {
ldbRemoveFromGlobal(snap, batch, folder, device, newName)
} else {
ldbUpdateGlobal(snap, batch, folder, device, newName, fs[fsi].Version)
}
fsi++
case moreFs && moreDb && cmp == 0:
// File exists on both sides - compare versions. We might get an
// update with the same version and different flags if a device has
// marked a file as invalid, so handle that too.
if debugDB {
l.Debugln("generic replace; exists - compare")
}
var ef FileInfoTruncated
ef.UnmarshalXDR(dbi.Value())
if fs[fsi].Version > ef.Version ||
(fs[fsi].Version == ef.Version && fs[fsi].Flags != ef.Flags) {
if debugDB {
l.Debugln("generic replace; differs - insert")
}
if lv := ldbInsert(batch, folder, device, fs[fsi]); lv > maxLocalVer {
maxLocalVer = lv
}
if fs[fsi].IsInvalid() {
ldbRemoveFromGlobal(snap, batch, folder, device, newName)
} else {
ldbUpdateGlobal(snap, batch, folder, device, newName, fs[fsi].Version)
}
} else if debugDB {
l.Debugln("generic replace; equal - ignore")
}
fsi++
moreDb = dbi.Next()
case moreDb && (!moreFs || cmp == 1):
if debugDB {
l.Debugln("generic replace; exists - remove")
}
if lv := deleteFn(snap, batch, folder, device, oldName, dbi); lv > maxLocalVer {
maxLocalVer = lv
}
moreDb = dbi.Next()
}
}
if debugDB {
l.Debugf("db.Write %p", batch)
}
err = db.Write(batch, nil)
if err != nil {
panic(err)
}
return maxLocalVer
}
// ldbUpdateGlobal adds this device+version to the version list for the given
// file. If the device is already present in the list, the version is updated.
// If the file does not have an entry in the global list, it is created.
func ldbUpdateGlobal(db dbReader, batch dbWriter, folder, device []byte, file protocol.FileInfo) bool {
if debugDB {
l.Debugf("update global; folder=%q device=%v file=%q version=%d", folder, protocol.DeviceIDFromBytes(device), file.Name, file.Version)
}
name := []byte(file.Name)
gk := globalKey(folder, name)
svl, err := db.Get(gk, nil)
if err != nil && err != leveldb.ErrNotFound {
panic(err)
}
var fl versionList
// Remove the device from the current version list
if svl != nil {
err = fl.UnmarshalXDR(svl)
if err != nil {
panic(err)
}
for i := range fl.versions {
if bytes.Compare(fl.versions[i].device, device) == 0 {
if fl.versions[i].version.Equal(file.Version) {
// No need to do anything
return false
}
fl.versions = append(fl.versions[:i], fl.versions[i+1:]...)
break
}
}
}
nv := fileVersion{
device: device,
version: file.Version,
}
// Find a position in the list to insert this file. The file at the front
// of the list is the newer, the "global".
for i := range fl.versions {
switch fl.versions[i].version.Compare(file.Version) {
case protocol.Equal, protocol.Lesser:
// The version at this point in the list is equal to or lesser
// ("older") than us. We insert ourselves in front of it.
fl.versions = insertVersion(fl.versions, i, nv)
goto done
case protocol.ConcurrentLesser, protocol.ConcurrentGreater:
// The version at this point is in conflict with us. We must pull
// the actual file metadata to determine who wins. If we win, we
// insert ourselves in front of the loser here. (The "Lesser" and
// "Greater" in the condition above is just based on the device
// IDs in the version vector, which is not the only thing we use
// to determine the winner.)
of, ok := ldbGet(db, folder, fl.versions[i].device, name)
if !ok {
panic("file referenced in version list does not exist")
}
if file.WinsConflict(of) {
fl.versions = insertVersion(fl.versions, i, nv)
goto done
}
}
}
// We didn't find a position for an insert above, so append to the end.
fl.versions = append(fl.versions, nv)
done:
if debugDB {
l.Debugf("batch.Put %p %x", batch, gk)
l.Debugf("new global after update: %v", fl)
}
batch.Put(gk, fl.MustMarshalXDR())
return true
}
func protocolConnectionHandler(tcpConn net.Conn, config *tls.Config) {
conn := tls.Server(tcpConn, config)
err := conn.Handshake()
if err != nil {
if debug {
log.Println("Protocol connection TLS handshake:", conn.RemoteAddr(), err)
}
conn.Close()
return
}
state := conn.ConnectionState()
if (!state.NegotiatedProtocolIsMutual || state.NegotiatedProtocol != protocol.ProtocolName) && debug {
log.Println("Protocol negotiation error")
}
certs := state.PeerCertificates
if len(certs) != 1 {
if debug {
log.Println("Certificate list error")
}
conn.Close()
return
}
id := syncthingprotocol.NewDeviceID(certs[0].Raw)
messages := make(chan interface{})
errors := make(chan error, 1)
outbox := make(chan interface{})
// Read messages from the connection and send them on the messages
// channel. When there is an error, send it on the error channel and
// return. Applies also when the connection gets closed, so the pattern
// below is to close the connection on error, then wait for the error
// signal from messageReader to exit.
go messageReader(conn, messages, errors)
pingTicker := time.NewTicker(pingInterval)
timeoutTicker := time.NewTimer(networkTimeout)
joined := false
for {
select {
case message := <-messages:
timeoutTicker.Reset(networkTimeout)
if debug {
log.Printf("Message %T from %s", message, id)
}
switch msg := message.(type) {
case protocol.JoinRelayRequest:
outboxesMut.RLock()
_, ok := outboxes[id]
outboxesMut.RUnlock()
if ok {
protocol.WriteMessage(conn, protocol.ResponseAlreadyConnected)
if debug {
log.Println("Already have a peer with the same ID", id, conn.RemoteAddr())
}
conn.Close()
continue
}
outboxesMut.Lock()
outboxes[id] = outbox
outboxesMut.Unlock()
joined = true
protocol.WriteMessage(conn, protocol.ResponseSuccess)
case protocol.ConnectRequest:
requestedPeer := syncthingprotocol.DeviceIDFromBytes(msg.ID)
outboxesMut.RLock()
peerOutbox, ok := outboxes[requestedPeer]
outboxesMut.RUnlock()
if !ok {
if debug {
log.Println(id, "is looking for", requestedPeer, "which does not exist")
}
protocol.WriteMessage(conn, protocol.ResponseNotFound)
conn.Close()
continue
}
ses := newSession(sessionLimiter, globalLimiter)
go ses.Serve()
clientInvitation := ses.GetClientInvitationMessage(requestedPeer)
serverInvitation := ses.GetServerInvitationMessage(id)
if err := protocol.WriteMessage(conn, clientInvitation); err != nil {
if debug {
log.Printf("Error sending invitation from %s to client: %s", id, err)
}
conn.Close()
continue
}
peerOutbox <- serverInvitation
if debug {
log.Println("Sent invitation from", id, "to", requestedPeer)
}
conn.Close()
case protocol.Pong:
// Nothing
default:
if debug {
log.Printf("Unknown message %s: %T", id, message)
}
protocol.WriteMessage(conn, protocol.ResponseUnexpectedMessage)
conn.Close()
}
case err := <-errors:
if debug {
log.Printf("Closing connection %s: %s", id, err)
}
close(outbox)
// Potentially closing a second time.
conn.Close()
// Only delete the outbox if the client is joined, as it might be
// a lookup request coming from the same client.
if joined {
outboxesMut.Lock()
delete(outboxes, id)
outboxesMut.Unlock()
}
return
case <-pingTicker.C:
if !joined {
if debug {
log.Println(id, "didn't join within", pingInterval)
}
conn.Close()
continue
}
if err := protocol.WriteMessage(conn, protocol.Ping{}); err != nil {
if debug {
log.Println(id, err)
}
conn.Close()
}
case <-timeoutTicker.C:
// We should receive a error from the reader loop, which will cause
// us to quit this loop.
if debug {
log.Printf("%s timed out", id)
}
conn.Close()
case msg := <-outbox:
if debug {
log.Printf("Sending message %T to %s", msg, id)
}
if err := protocol.WriteMessage(conn, msg); err != nil {
if debug {
log.Println(id, err)
}
conn.Close()
}
}
}
}