syncthing/lib/protocol/protocol.go
André Colomb ab0eb909a2
gui, lib/connections: Let the backend decide whether connection is local (fixes #8686) (#8694)
* lib/connections: Cache isLAN decision for later external access.

The check whether a remote device's address is on a local network
currently happens when handling the Hello message, to configure the
limiters.  Save the result to the ConnectionInfo and pass it out as
part of the model's ConnectionInfo struct in ConnectionStats().

* gui: Use provided connection attribute to distinguish LAN / WAN.

Replace the dumb IP address check which didn't catch common cases and
actually could contradict what the backend decided.  That could have
been confusing if the GUI says WAN, but the limiter is not actually
applied because the backend thinks it's a LAN.

Add strings for QUIC and relay connections to also differentiate
between LAN and WAN.

* gui: Redefine reception level icons for all connection types.

Move the mapping to the JS code, as it is much easier to handle
multiple switch cases by fall-through there.

QUIC is regarded no less than TCP anymore.  LAN and WAN make the
difference between levels 4 / 3 and 2 / 1:

{TCP,QUIC} LAN --> {TCP,QUIC} WAN --> Relay LAN --> Relay WAN -->
Disconnected.
2022-11-28 09:28:33 +01:00

1073 lines
29 KiB
Go

// Copyright (C) 2014 The Protocol Authors.
//go:generate -command counterfeiter go run github.com/maxbrunsfeld/counterfeiter/v6
// Prevents import loop, for internal testing
//go:generate counterfeiter -o mocked_connection_info_test.go --fake-name mockedConnectionInfo . ConnectionInfo
//go:generate go run ../../script/prune_mocks.go -t mocked_connection_info_test.go
//go:generate counterfeiter -o mocks/connection_info.go --fake-name ConnectionInfo . ConnectionInfo
//go:generate counterfeiter -o mocks/connection.go --fake-name Connection . Connection
package protocol
import (
"context"
"crypto/sha256"
"encoding/binary"
"errors"
"fmt"
"io"
"net"
"path"
"strings"
"sync"
"time"
lz4 "github.com/pierrec/lz4/v4"
)
const (
// Shifts
KiB = 10
MiB = 20
GiB = 30
)
const (
// MaxMessageLen is the largest message size allowed on the wire. (500 MB)
MaxMessageLen = 500 * 1000 * 1000
// MinBlockSize is the minimum block size allowed
MinBlockSize = 128 << KiB
// MaxBlockSize is the maximum block size allowed
MaxBlockSize = 16 << MiB
// DesiredPerFileBlocks is the number of blocks we aim for per file
DesiredPerFileBlocks = 2000
)
// BlockSizes is the list of valid block sizes, from min to max
var BlockSizes []int
// For each block size, the hash of a block of all zeroes
var sha256OfEmptyBlock = map[int][sha256.Size]byte{
128 << KiB: {0xfa, 0x43, 0x23, 0x9b, 0xce, 0xe7, 0xb9, 0x7c, 0xa6, 0x2f, 0x0, 0x7c, 0xc6, 0x84, 0x87, 0x56, 0xa, 0x39, 0xe1, 0x9f, 0x74, 0xf3, 0xdd, 0xe7, 0x48, 0x6d, 0xb3, 0xf9, 0x8d, 0xf8, 0xe4, 0x71},
256 << KiB: {0x8a, 0x39, 0xd2, 0xab, 0xd3, 0x99, 0x9a, 0xb7, 0x3c, 0x34, 0xdb, 0x24, 0x76, 0x84, 0x9c, 0xdd, 0xf3, 0x3, 0xce, 0x38, 0x9b, 0x35, 0x82, 0x68, 0x50, 0xf9, 0xa7, 0x0, 0x58, 0x9b, 0x4a, 0x90},
512 << KiB: {0x7, 0x85, 0x4d, 0x2f, 0xef, 0x29, 0x7a, 0x6, 0xba, 0x81, 0x68, 0x5e, 0x66, 0xc, 0x33, 0x2d, 0xe3, 0x6d, 0x5d, 0x18, 0xd5, 0x46, 0x92, 0x7d, 0x30, 0xda, 0xad, 0x6d, 0x7f, 0xda, 0x15, 0x41},
1 << MiB: {0x30, 0xe1, 0x49, 0x55, 0xeb, 0xf1, 0x35, 0x22, 0x66, 0xdc, 0x2f, 0xf8, 0x6, 0x7e, 0x68, 0x10, 0x46, 0x7, 0xe7, 0x50, 0xab, 0xb9, 0xd3, 0xb3, 0x65, 0x82, 0xb8, 0xaf, 0x90, 0x9f, 0xcb, 0x58},
2 << MiB: {0x56, 0x47, 0xf0, 0x5e, 0xc1, 0x89, 0x58, 0x94, 0x7d, 0x32, 0x87, 0x4e, 0xeb, 0x78, 0x8f, 0xa3, 0x96, 0xa0, 0x5d, 0xb, 0xab, 0x7c, 0x1b, 0x71, 0xf1, 0x12, 0xce, 0xb7, 0xe9, 0xb3, 0x1e, 0xee},
4 << MiB: {0xbb, 0x9f, 0x8d, 0xf6, 0x14, 0x74, 0xd2, 0x5e, 0x71, 0xfa, 0x0, 0x72, 0x23, 0x18, 0xcd, 0x38, 0x73, 0x96, 0xca, 0x17, 0x36, 0x60, 0x5e, 0x12, 0x48, 0x82, 0x1c, 0xc0, 0xde, 0x3d, 0x3a, 0xf8},
8 << MiB: {0x2d, 0xae, 0xb1, 0xf3, 0x60, 0x95, 0xb4, 0x4b, 0x31, 0x84, 0x10, 0xb3, 0xf4, 0xe8, 0xb5, 0xd9, 0x89, 0xdc, 0xc7, 0xbb, 0x2, 0x3d, 0x14, 0x26, 0xc4, 0x92, 0xda, 0xb0, 0xa3, 0x5, 0x3e, 0x74},
16 << MiB: {0x8, 0xa, 0xcf, 0x35, 0xa5, 0x7, 0xac, 0x98, 0x49, 0xcf, 0xcb, 0xa4, 0x7d, 0xc2, 0xad, 0x83, 0xe0, 0x1b, 0x75, 0x66, 0x3a, 0x51, 0x62, 0x79, 0xc8, 0xb9, 0xd2, 0x43, 0xb7, 0x19, 0x64, 0x3e},
}
var (
errNotCompressible = errors.New("not compressible")
)
func init() {
for blockSize := MinBlockSize; blockSize <= MaxBlockSize; blockSize *= 2 {
BlockSizes = append(BlockSizes, blockSize)
if _, ok := sha256OfEmptyBlock[blockSize]; !ok {
panic("missing hard coded value for sha256 of empty block")
}
}
BufferPool = newBufferPool()
}
// BlockSize returns the block size to use for the given file size
func BlockSize(fileSize int64) int {
var blockSize int
for _, blockSize = range BlockSizes {
if fileSize < DesiredPerFileBlocks*int64(blockSize) {
break
}
}
return blockSize
}
const (
stateInitial = iota
stateReady
)
// FileInfo.LocalFlags flags
const (
FlagLocalUnsupported = 1 << 0 // The kind is unsupported, e.g. symlinks on Windows
FlagLocalIgnored = 1 << 1 // Matches local ignore patterns
FlagLocalMustRescan = 1 << 2 // Doesn't match content on disk, must be rechecked fully
FlagLocalReceiveOnly = 1 << 3 // Change detected on receive only folder
// Flags that should result in the Invalid bit on outgoing updates
LocalInvalidFlags = FlagLocalUnsupported | FlagLocalIgnored | FlagLocalMustRescan | FlagLocalReceiveOnly
// Flags that should result in a file being in conflict with its
// successor, due to us not having an up to date picture of its state on
// disk.
LocalConflictFlags = FlagLocalUnsupported | FlagLocalIgnored | FlagLocalReceiveOnly
LocalAllFlags = FlagLocalUnsupported | FlagLocalIgnored | FlagLocalMustRescan | FlagLocalReceiveOnly
)
var (
ErrClosed = errors.New("connection closed")
ErrTimeout = errors.New("read timeout")
errUnknownMessage = errors.New("unknown message")
errInvalidFilename = errors.New("filename is invalid")
errUncleanFilename = errors.New("filename not in canonical format")
errDeletedHasBlocks = errors.New("deleted file with non-empty block list")
errDirectoryHasBlocks = errors.New("directory with non-empty block list")
errFileHasNoBlocks = errors.New("file with empty block list")
)
type Model interface {
// An index was received from the peer device
Index(deviceID DeviceID, folder string, files []FileInfo) error
// An index update was received from the peer device
IndexUpdate(deviceID DeviceID, folder string, files []FileInfo) error
// A request was made by the peer device
Request(deviceID DeviceID, folder, name string, blockNo, size int32, offset int64, hash []byte, weakHash uint32, fromTemporary bool) (RequestResponse, error)
// A cluster configuration message was received
ClusterConfig(deviceID DeviceID, config ClusterConfig) error
// The peer device closed the connection or an error occurred
Closed(device DeviceID, err error)
// The peer device sent progress updates for the files it is currently downloading
DownloadProgress(deviceID DeviceID, folder string, updates []FileDownloadProgressUpdate) error
}
type RequestResponse interface {
Data() []byte
Close() // Must always be called once the byte slice is no longer in use
Wait() // Blocks until Close is called
}
type Connection interface {
Start()
SetFolderPasswords(passwords map[string]string)
Close(err error)
ID() DeviceID
Index(ctx context.Context, folder string, files []FileInfo) error
IndexUpdate(ctx context.Context, folder string, files []FileInfo) error
Request(ctx context.Context, folder string, name string, blockNo int, offset int64, size int, hash []byte, weakHash uint32, fromTemporary bool) ([]byte, error)
ClusterConfig(config ClusterConfig)
DownloadProgress(ctx context.Context, folder string, updates []FileDownloadProgressUpdate)
Statistics() Statistics
Closed() <-chan struct{}
ConnectionInfo
}
type ConnectionInfo interface {
Type() string
Transport() string
IsLocal() bool
RemoteAddr() net.Addr
Priority() int
String() string
Crypto() string
EstablishedAt() time.Time
}
type rawConnection struct {
ConnectionInfo
id DeviceID
receiver Model
startTime time.Time
cr *countingReader
cw *countingWriter
closer io.Closer // Closing the underlying connection and thus cr and cw
awaitingMut sync.Mutex // Protects awaiting and nextID.
awaiting map[int]chan asyncResult
nextID int
idxMut sync.Mutex // ensures serialization of Index calls
inbox chan message
outbox chan asyncMessage
closeBox chan asyncMessage
clusterConfigBox chan *ClusterConfig
dispatcherLoopStopped chan struct{}
closed chan struct{}
closeOnce sync.Once
sendCloseOnce sync.Once
compression Compression
loopWG sync.WaitGroup // Need to ensure no leftover routines in testing
}
type asyncResult struct {
val []byte
err error
}
type message interface {
ProtoSize() int
Marshal() ([]byte, error)
MarshalTo([]byte) (int, error)
Unmarshal([]byte) error
}
type asyncMessage struct {
msg message
done chan struct{} // done closes when we're done sending the message
}
const (
// PingSendInterval is how often we make sure to send a message, by
// triggering pings if necessary.
PingSendInterval = 90 * time.Second
// ReceiveTimeout is the longest we'll wait for a message from the other
// side before closing the connection.
ReceiveTimeout = 300 * time.Second
)
// CloseTimeout is the longest we'll wait when trying to send the close
// message before just closing the connection.
// Should not be modified in production code, just for testing.
var CloseTimeout = 10 * time.Second
func NewConnection(deviceID DeviceID, reader io.Reader, writer io.Writer, closer io.Closer, receiver Model, connInfo ConnectionInfo, compress Compression, passwords map[string]string) Connection {
// Encryption / decryption is first (outermost) before conversion to
// native path formats.
nm := makeNative(receiver)
em := &encryptedModel{model: nm, folderKeys: newFolderKeyRegistry(passwords)}
// We do the wire format conversion first (outermost) so that the
// metadata is in wire format when it reaches the encryption step.
rc := newRawConnection(deviceID, reader, writer, closer, em, connInfo, compress)
ec := encryptedConnection{ConnectionInfo: rc, conn: rc, folderKeys: em.folderKeys}
wc := wireFormatConnection{ec}
return wc
}
func newRawConnection(deviceID DeviceID, reader io.Reader, writer io.Writer, closer io.Closer, receiver Model, connInfo ConnectionInfo, compress Compression) *rawConnection {
cr := &countingReader{Reader: reader}
cw := &countingWriter{Writer: writer}
return &rawConnection{
ConnectionInfo: connInfo,
id: deviceID,
receiver: receiver,
cr: cr,
cw: cw,
closer: closer,
awaiting: make(map[int]chan asyncResult),
inbox: make(chan message),
outbox: make(chan asyncMessage),
closeBox: make(chan asyncMessage),
clusterConfigBox: make(chan *ClusterConfig),
dispatcherLoopStopped: make(chan struct{}),
closed: make(chan struct{}),
compression: compress,
loopWG: sync.WaitGroup{},
}
}
// Start creates the goroutines for sending and receiving of messages. It must
// be called exactly once after creating a connection.
func (c *rawConnection) Start() {
c.loopWG.Add(5)
go func() {
c.readerLoop()
c.loopWG.Done()
}()
go func() {
err := c.dispatcherLoop()
c.Close(err)
c.loopWG.Done()
}()
go func() {
c.writerLoop()
c.loopWG.Done()
}()
go func() {
c.pingSender()
c.loopWG.Done()
}()
go func() {
c.pingReceiver()
c.loopWG.Done()
}()
c.startTime = time.Now().Truncate(time.Second)
}
func (c *rawConnection) ID() DeviceID {
return c.id
}
// Index writes the list of file information to the connected peer device
func (c *rawConnection) Index(ctx context.Context, folder string, idx []FileInfo) error {
select {
case <-c.closed:
return ErrClosed
default:
}
c.idxMut.Lock()
c.send(ctx, &Index{
Folder: folder,
Files: idx,
}, nil)
c.idxMut.Unlock()
return nil
}
// IndexUpdate writes the list of file information to the connected peer device as an update
func (c *rawConnection) IndexUpdate(ctx context.Context, folder string, idx []FileInfo) error {
select {
case <-c.closed:
return ErrClosed
default:
}
c.idxMut.Lock()
c.send(ctx, &IndexUpdate{
Folder: folder,
Files: idx,
}, nil)
c.idxMut.Unlock()
return nil
}
// Request returns the bytes for the specified block after fetching them from the connected peer.
func (c *rawConnection) Request(ctx context.Context, folder string, name string, blockNo int, offset int64, size int, hash []byte, weakHash uint32, fromTemporary bool) ([]byte, error) {
rc := make(chan asyncResult, 1)
c.awaitingMut.Lock()
id := c.nextID
c.nextID++
if _, ok := c.awaiting[id]; ok {
c.awaitingMut.Unlock()
panic("id taken")
}
c.awaiting[id] = rc
c.awaitingMut.Unlock()
ok := c.send(ctx, &Request{
ID: id,
Folder: folder,
Name: name,
Offset: offset,
Size: size,
BlockNo: blockNo,
Hash: hash,
WeakHash: weakHash,
FromTemporary: fromTemporary,
}, nil)
if !ok {
return nil, ErrClosed
}
select {
case res, ok := <-rc:
if !ok {
return nil, ErrClosed
}
return res.val, res.err
case <-ctx.Done():
return nil, ctx.Err()
}
}
// ClusterConfig sends the cluster configuration message to the peer.
func (c *rawConnection) ClusterConfig(config ClusterConfig) {
select {
case c.clusterConfigBox <- &config:
case <-c.closed:
}
}
func (c *rawConnection) Closed() <-chan struct{} {
return c.closed
}
// DownloadProgress sends the progress updates for the files that are currently being downloaded.
func (c *rawConnection) DownloadProgress(ctx context.Context, folder string, updates []FileDownloadProgressUpdate) {
c.send(ctx, &DownloadProgress{
Folder: folder,
Updates: updates,
}, nil)
}
func (c *rawConnection) ping() bool {
return c.send(context.Background(), &Ping{}, nil)
}
func (c *rawConnection) readerLoop() {
fourByteBuf := make([]byte, 4)
for {
msg, err := c.readMessage(fourByteBuf)
if err != nil {
if err == errUnknownMessage {
// Unknown message types are skipped, for future extensibility.
continue
}
c.internalClose(err)
return
}
select {
case c.inbox <- msg:
case <-c.closed:
return
}
}
}
func (c *rawConnection) dispatcherLoop() (err error) {
defer close(c.dispatcherLoopStopped)
var msg message
state := stateInitial
for {
select {
case msg = <-c.inbox:
case <-c.closed:
return ErrClosed
}
msgContext, err := messageContext(msg)
if err != nil {
return fmt.Errorf("protocol error: %w", err)
}
l.Debugf("handle %v message", msgContext)
switch msg := msg.(type) {
case *ClusterConfig:
if state == stateInitial {
state = stateReady
}
case *Close:
return fmt.Errorf("closed by remote: %v", msg.Reason)
default:
if state != stateReady {
return newProtocolError(fmt.Errorf("invalid state %d", state), msgContext)
}
}
switch msg := msg.(type) {
case *Index:
err = checkIndexConsistency(msg.Files)
case *IndexUpdate:
err = checkIndexConsistency(msg.Files)
case *Request:
err = checkFilename(msg.Name)
}
if err != nil {
return newProtocolError(err, msgContext)
}
switch msg := msg.(type) {
case *ClusterConfig:
err = c.receiver.ClusterConfig(c.id, *msg)
case *Index:
err = c.handleIndex(*msg)
case *IndexUpdate:
err = c.handleIndexUpdate(*msg)
case *Request:
go c.handleRequest(*msg)
case *Response:
c.handleResponse(*msg)
case *DownloadProgress:
err = c.receiver.DownloadProgress(c.id, msg.Folder, msg.Updates)
}
if err != nil {
return newHandleError(err, msgContext)
}
}
}
func (c *rawConnection) readMessage(fourByteBuf []byte) (message, error) {
hdr, err := c.readHeader(fourByteBuf)
if err != nil {
return nil, err
}
return c.readMessageAfterHeader(hdr, fourByteBuf)
}
func (c *rawConnection) readMessageAfterHeader(hdr Header, fourByteBuf []byte) (message, error) {
// First comes a 4 byte message length
if _, err := io.ReadFull(c.cr, fourByteBuf[:4]); err != nil {
return nil, fmt.Errorf("reading message length: %w", err)
}
msgLen := int32(binary.BigEndian.Uint32(fourByteBuf))
if msgLen < 0 {
return nil, fmt.Errorf("negative message length %d", msgLen)
} else if msgLen > MaxMessageLen {
return nil, fmt.Errorf("message length %d exceeds maximum %d", msgLen, MaxMessageLen)
}
// Then comes the message
buf := BufferPool.Get(int(msgLen))
if _, err := io.ReadFull(c.cr, buf); err != nil {
BufferPool.Put(buf)
return nil, fmt.Errorf("reading message: %w", err)
}
// ... which might be compressed
switch hdr.Compression {
case MessageCompressionNone:
// Nothing
case MessageCompressionLZ4:
decomp, err := lz4Decompress(buf)
BufferPool.Put(buf)
if err != nil {
return nil, fmt.Errorf("decompressing message: %w", err)
}
buf = decomp
default:
return nil, fmt.Errorf("unknown message compression %d", hdr.Compression)
}
// ... and is then unmarshalled
msg, err := newMessage(hdr.Type)
if err != nil {
BufferPool.Put(buf)
return nil, err
}
if err := msg.Unmarshal(buf); err != nil {
BufferPool.Put(buf)
return nil, fmt.Errorf("unmarshalling message: %w", err)
}
BufferPool.Put(buf)
return msg, nil
}
func (c *rawConnection) readHeader(fourByteBuf []byte) (Header, error) {
// First comes a 2 byte header length
if _, err := io.ReadFull(c.cr, fourByteBuf[:2]); err != nil {
return Header{}, fmt.Errorf("reading length: %w", err)
}
hdrLen := int16(binary.BigEndian.Uint16(fourByteBuf))
if hdrLen < 0 {
return Header{}, fmt.Errorf("negative header length %d", hdrLen)
}
// Then comes the header
buf := BufferPool.Get(int(hdrLen))
if _, err := io.ReadFull(c.cr, buf); err != nil {
BufferPool.Put(buf)
return Header{}, fmt.Errorf("reading header: %w", err)
}
var hdr Header
err := hdr.Unmarshal(buf)
BufferPool.Put(buf)
if err != nil {
return Header{}, fmt.Errorf("unmarshalling header: %w", err)
}
return hdr, nil
}
func (c *rawConnection) handleIndex(im Index) error {
l.Debugf("Index(%v, %v, %d file)", c.id, im.Folder, len(im.Files))
return c.receiver.Index(c.id, im.Folder, im.Files)
}
func (c *rawConnection) handleIndexUpdate(im IndexUpdate) error {
l.Debugf("queueing IndexUpdate(%v, %v, %d files)", c.id, im.Folder, len(im.Files))
return c.receiver.IndexUpdate(c.id, im.Folder, im.Files)
}
// checkIndexConsistency verifies a number of invariants on FileInfos received in
// index messages.
func checkIndexConsistency(fs []FileInfo) error {
for _, f := range fs {
if err := checkFileInfoConsistency(f); err != nil {
return fmt.Errorf("%q: %w", f.Name, err)
}
}
return nil
}
// checkFileInfoConsistency verifies a number of invariants on the given FileInfo
func checkFileInfoConsistency(f FileInfo) error {
if err := checkFilename(f.Name); err != nil {
return err
}
switch {
case f.Deleted && len(f.Blocks) != 0:
// Deleted files should have no blocks
return errDeletedHasBlocks
case f.Type == FileInfoTypeDirectory && len(f.Blocks) != 0:
// Directories should have no blocks
return errDirectoryHasBlocks
case !f.Deleted && !f.IsInvalid() && f.Type == FileInfoTypeFile && len(f.Blocks) == 0:
// Non-deleted, non-invalid files should have at least one block
return errFileHasNoBlocks
}
return nil
}
// checkFilename verifies that the given filename is valid according to the
// spec on what's allowed over the wire. A filename failing this test is
// grounds for disconnecting the device.
func checkFilename(name string) error {
cleanedName := path.Clean(name)
if cleanedName != name {
// The filename on the wire should be in canonical format. If
// Clean() managed to clean it up, there was something wrong with
// it.
return errUncleanFilename
}
switch name {
case "", ".", "..":
// These names are always invalid.
return errInvalidFilename
}
if strings.HasPrefix(name, "/") {
// Names are folder relative, not absolute.
return errInvalidFilename
}
if strings.HasPrefix(name, "../") {
// Starting with a dotdot is not allowed. Any other dotdots would
// have been handled by the Clean() call at the top.
return errInvalidFilename
}
return nil
}
func (c *rawConnection) handleRequest(req Request) {
res, err := c.receiver.Request(c.id, req.Folder, req.Name, int32(req.BlockNo), int32(req.Size), req.Offset, req.Hash, req.WeakHash, req.FromTemporary)
if err != nil {
c.send(context.Background(), &Response{
ID: req.ID,
Code: errorToCode(err),
}, nil)
return
}
done := make(chan struct{})
c.send(context.Background(), &Response{
ID: req.ID,
Data: res.Data(),
Code: errorToCode(nil),
}, done)
<-done
res.Close()
}
func (c *rawConnection) handleResponse(resp Response) {
c.awaitingMut.Lock()
if rc := c.awaiting[resp.ID]; rc != nil {
delete(c.awaiting, resp.ID)
rc <- asyncResult{resp.Data, codeToError(resp.Code)}
close(rc)
}
c.awaitingMut.Unlock()
}
func (c *rawConnection) send(ctx context.Context, msg message, done chan struct{}) bool {
select {
case c.outbox <- asyncMessage{msg, done}:
return true
case <-c.closed:
case <-ctx.Done():
}
if done != nil {
close(done)
}
return false
}
func (c *rawConnection) writerLoop() {
select {
case cc := <-c.clusterConfigBox:
err := c.writeMessage(cc)
if err != nil {
c.internalClose(err)
return
}
case hm := <-c.closeBox:
_ = c.writeMessage(hm.msg)
close(hm.done)
return
case <-c.closed:
return
}
for {
select {
case cc := <-c.clusterConfigBox:
err := c.writeMessage(cc)
if err != nil {
c.internalClose(err)
return
}
case hm := <-c.outbox:
err := c.writeMessage(hm.msg)
if hm.done != nil {
close(hm.done)
}
if err != nil {
c.internalClose(err)
return
}
case hm := <-c.closeBox:
_ = c.writeMessage(hm.msg)
close(hm.done)
return
case <-c.closed:
return
}
}
}
func (c *rawConnection) writeMessage(msg message) error {
msgContext, _ := messageContext(msg)
l.Debugf("Writing %v", msgContext)
size := msg.ProtoSize()
hdr := Header{
Type: typeOf(msg),
}
hdrSize := hdr.ProtoSize()
if hdrSize > 1<<16-1 {
panic("impossibly large header")
}
overhead := 2 + hdrSize + 4
totSize := overhead + size
buf := BufferPool.Get(totSize)
defer BufferPool.Put(buf)
// Message
if _, err := msg.MarshalTo(buf[2+hdrSize+4:]); err != nil {
return fmt.Errorf("marshalling message: %w", err)
}
if c.shouldCompressMessage(msg) {
ok, err := c.writeCompressedMessage(msg, buf[overhead:])
if ok {
return err
}
}
// Header length
binary.BigEndian.PutUint16(buf, uint16(hdrSize))
// Header
if _, err := hdr.MarshalTo(buf[2:]); err != nil {
return fmt.Errorf("marshalling header: %w", err)
}
// Message length
binary.BigEndian.PutUint32(buf[2+hdrSize:], uint32(size))
n, err := c.cw.Write(buf)
l.Debugf("wrote %d bytes on the wire (2 bytes length, %d bytes header, 4 bytes message length, %d bytes message), err=%v", n, hdrSize, size, err)
if err != nil {
return fmt.Errorf("writing message: %w", err)
}
return nil
}
// Write msg out compressed, given its uncompressed marshaled payload.
//
// The first return value indicates whether compression succeeded.
// If not, the caller should retry without compression.
func (c *rawConnection) writeCompressedMessage(msg message, marshaled []byte) (ok bool, err error) {
hdr := Header{
Type: typeOf(msg),
Compression: MessageCompressionLZ4,
}
hdrSize := hdr.ProtoSize()
if hdrSize > 1<<16-1 {
panic("impossibly large header")
}
cOverhead := 2 + hdrSize + 4
// The compressed size may be at most n-n/32 = .96875*n bytes,
// I.e., if we can't save at least 3.125% bandwidth, we forgo compression.
// This number is arbitrary but cheap to compute.
maxCompressed := cOverhead + len(marshaled) - len(marshaled)/32
buf := BufferPool.Get(maxCompressed)
defer BufferPool.Put(buf)
compressedSize, err := lz4Compress(marshaled, buf[cOverhead:])
totSize := compressedSize + cOverhead
if err != nil {
return false, nil
}
// Header length
binary.BigEndian.PutUint16(buf, uint16(hdrSize))
// Header
if _, err := hdr.MarshalTo(buf[2:]); err != nil {
return true, fmt.Errorf("marshalling header: %w", err)
}
// Message length
binary.BigEndian.PutUint32(buf[2+hdrSize:], uint32(compressedSize))
n, err := c.cw.Write(buf[:totSize])
l.Debugf("wrote %d bytes on the wire (2 bytes length, %d bytes header, 4 bytes message length, %d bytes message (%d uncompressed)), err=%v", n, hdrSize, compressedSize, len(marshaled), err)
if err != nil {
return true, fmt.Errorf("writing message: %w", err)
}
return true, nil
}
func typeOf(msg message) MessageType {
switch msg.(type) {
case *ClusterConfig:
return MessageTypeClusterConfig
case *Index:
return MessageTypeIndex
case *IndexUpdate:
return MessageTypeIndexUpdate
case *Request:
return MessageTypeRequest
case *Response:
return MessageTypeResponse
case *DownloadProgress:
return MessageTypeDownloadProgress
case *Ping:
return MessageTypePing
case *Close:
return MessageTypeClose
default:
panic("bug: unknown message type")
}
}
func newMessage(t MessageType) (message, error) {
switch t {
case MessageTypeClusterConfig:
return new(ClusterConfig), nil
case MessageTypeIndex:
return new(Index), nil
case MessageTypeIndexUpdate:
return new(IndexUpdate), nil
case MessageTypeRequest:
return new(Request), nil
case MessageTypeResponse:
return new(Response), nil
case MessageTypeDownloadProgress:
return new(DownloadProgress), nil
case MessageTypePing:
return new(Ping), nil
case MessageTypeClose:
return new(Close), nil
default:
return nil, errUnknownMessage
}
}
func (c *rawConnection) shouldCompressMessage(msg message) bool {
switch c.compression {
case CompressionNever:
return false
case CompressionAlways:
// Use compression for large enough messages
return msg.ProtoSize() >= compressionThreshold
case CompressionMetadata:
_, isResponse := msg.(*Response)
// Compress if it's large enough and not a response message
return !isResponse && msg.ProtoSize() >= compressionThreshold
default:
panic("unknown compression setting")
}
}
// Close is called when the connection is regularely closed and thus the Close
// BEP message is sent before terminating the actual connection. The error
// argument specifies the reason for closing the connection.
func (c *rawConnection) Close(err error) {
c.sendCloseOnce.Do(func() {
done := make(chan struct{})
timeout := time.NewTimer(CloseTimeout)
select {
case c.closeBox <- asyncMessage{&Close{err.Error()}, done}:
select {
case <-done:
case <-timeout.C:
case <-c.closed:
}
case <-timeout.C:
case <-c.closed:
}
})
// Close might be called from a method that is called from within
// dispatcherLoop, resulting in a deadlock.
// The sending above must happen before spawning the routine, to prevent
// the underlying connection from terminating before sending the close msg.
go c.internalClose(err)
}
// internalClose is called if there is an unexpected error during normal operation.
func (c *rawConnection) internalClose(err error) {
c.closeOnce.Do(func() {
l.Debugln("close due to", err)
if cerr := c.closer.Close(); cerr != nil {
l.Debugln(c.id, "failed to close underlying conn:", cerr)
}
close(c.closed)
c.awaitingMut.Lock()
for i, ch := range c.awaiting {
if ch != nil {
close(ch)
delete(c.awaiting, i)
}
}
c.awaitingMut.Unlock()
<-c.dispatcherLoopStopped
c.receiver.Closed(c.ID(), err)
})
}
// The pingSender makes sure that we've sent a message within the last
// PingSendInterval. If we already have something sent in the last
// PingSendInterval/2, we do nothing. Otherwise we send a ping message. This
// results in an effecting ping interval of somewhere between
// PingSendInterval/2 and PingSendInterval.
func (c *rawConnection) pingSender() {
ticker := time.NewTicker(PingSendInterval / 2)
defer ticker.Stop()
for {
select {
case <-ticker.C:
d := time.Since(c.cw.Last())
if d < PingSendInterval/2 {
l.Debugln(c.id, "ping skipped after wr", d)
continue
}
l.Debugln(c.id, "ping -> after", d)
c.ping()
case <-c.closed:
return
}
}
}
// The pingReceiver checks that we've received a message (any message will do,
// but we expect pings in the absence of other messages) within the last
// ReceiveTimeout. If not, we close the connection with an ErrTimeout.
func (c *rawConnection) pingReceiver() {
ticker := time.NewTicker(ReceiveTimeout / 2)
defer ticker.Stop()
for {
select {
case <-ticker.C:
d := time.Since(c.cr.Last())
if d > ReceiveTimeout {
l.Debugln(c.id, "ping timeout", d)
c.internalClose(ErrTimeout)
}
l.Debugln(c.id, "last read within", d)
case <-c.closed:
return
}
}
}
type Statistics struct {
At time.Time `json:"at"`
InBytesTotal int64 `json:"inBytesTotal"`
OutBytesTotal int64 `json:"outBytesTotal"`
StartedAt time.Time `json:"startedAt"`
}
func (c *rawConnection) Statistics() Statistics {
return Statistics{
At: time.Now().Truncate(time.Second),
InBytesTotal: c.cr.Tot(),
OutBytesTotal: c.cw.Tot(),
StartedAt: c.startTime,
}
}
func lz4Compress(src, buf []byte) (int, error) {
n, err := lz4.CompressBlock(src, buf[4:], nil)
if err != nil {
return -1, err
} else if n == 0 {
return -1, errNotCompressible
}
// The compressed block is prefixed by the size of the uncompressed data.
binary.BigEndian.PutUint32(buf, uint32(len(src)))
return n + 4, nil
}
func lz4Decompress(src []byte) ([]byte, error) {
size := binary.BigEndian.Uint32(src)
buf := BufferPool.Get(int(size))
n, err := lz4.UncompressBlock(src[4:], buf)
if err != nil {
BufferPool.Put(buf)
return nil, err
}
return buf[:n], nil
}
func newProtocolError(err error, msgContext string) error {
return fmt.Errorf("protocol error on %v: %w", msgContext, err)
}
func newHandleError(err error, msgContext string) error {
return fmt.Errorf("handling %v: %w", msgContext, err)
}
func messageContext(msg message) (string, error) {
switch msg := msg.(type) {
case *ClusterConfig:
return "cluster-config", nil
case *Index:
return fmt.Sprintf("index for %v", msg.Folder), nil
case *IndexUpdate:
return fmt.Sprintf("index-update for %v", msg.Folder), nil
case *Request:
return fmt.Sprintf(`request for "%v" in %v`, msg.Name, msg.Folder), nil
case *Response:
return "response", nil
case *DownloadProgress:
return fmt.Sprintf("download-progress for %v", msg.Folder), nil
case *Ping:
return "ping", nil
case *Close:
return "close", nil
default:
return "", errors.New("unknown or empty message")
}
}