720 lines
16 KiB
Go
720 lines
16 KiB
Go
// Copyright (C) 2014 The Protocol Authors.
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package protocol
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import (
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"encoding/binary"
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"encoding/hex"
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"errors"
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"fmt"
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"io"
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"sync"
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"time"
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lz4 "github.com/bkaradzic/go-lz4"
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)
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const (
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BlockSize = 128 * 1024
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)
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const (
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messageTypeClusterConfig = 0
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messageTypeIndex = 1
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messageTypeRequest = 2
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messageTypeResponse = 3
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messageTypePing = 4
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messageTypePong = 5
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messageTypeIndexUpdate = 6
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messageTypeClose = 7
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)
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const (
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stateInitial = iota
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stateCCRcvd
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stateIdxRcvd
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)
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const (
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FlagDeleted uint32 = 1 << 12
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FlagInvalid = 1 << 13
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FlagDirectory = 1 << 14
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FlagNoPermBits = 1 << 15
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FlagSymlink = 1 << 16
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FlagSymlinkMissingTarget = 1 << 17
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SymlinkTypeMask = FlagDirectory | FlagSymlinkMissingTarget
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)
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const (
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FlagShareTrusted uint32 = 1 << 0
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FlagShareReadOnly = 1 << 1
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FlagIntroducer = 1 << 2
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FlagShareBits = 0x000000ff
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)
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var (
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ErrClusterHash = fmt.Errorf("configuration error: mismatched cluster hash")
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ErrClosed = errors.New("connection closed")
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)
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// Specific variants of empty messages...
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type pingMessage struct{ EmptyMessage }
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type pongMessage struct{ EmptyMessage }
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type Model interface {
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// An index was received from the peer device
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Index(deviceID DeviceID, folder string, files []FileInfo)
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// An index update was received from the peer device
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IndexUpdate(deviceID DeviceID, folder string, files []FileInfo)
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// A request was made by the peer device
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Request(deviceID DeviceID, folder string, name string, offset int64, size int) ([]byte, error)
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// A cluster configuration message was received
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ClusterConfig(deviceID DeviceID, config ClusterConfigMessage)
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// The peer device closed the connection
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Close(deviceID DeviceID, err error)
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}
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type Connection interface {
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ID() DeviceID
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Name() string
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Index(folder string, files []FileInfo) error
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IndexUpdate(folder string, files []FileInfo) error
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Request(folder string, name string, offset int64, size int) ([]byte, error)
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ClusterConfig(config ClusterConfigMessage)
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Statistics() Statistics
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}
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type rawConnection struct {
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id DeviceID
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name string
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receiver Model
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state int
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cr *countingReader
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cw *countingWriter
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awaiting [4096]chan asyncResult
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awaitingMut sync.Mutex
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idxMut sync.Mutex // ensures serialization of Index calls
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nextID chan int
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outbox chan hdrMsg
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closed chan struct{}
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once sync.Once
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compressionThreshold int // compress messages larger than this many bytes
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rdbuf0 []byte // used & reused by readMessage
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rdbuf1 []byte // used & reused by readMessage
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}
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type asyncResult struct {
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val []byte
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err error
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}
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type hdrMsg struct {
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hdr header
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msg encodable
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}
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type encodable interface {
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AppendXDR([]byte) ([]byte, error)
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}
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type isEofer interface {
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IsEOF() bool
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}
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const (
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pingTimeout = 30 * time.Second
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pingIdleTime = 60 * time.Second
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)
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func NewConnection(deviceID DeviceID, reader io.Reader, writer io.Writer, receiver Model, name string, compress bool) Connection {
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cr := &countingReader{Reader: reader}
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cw := &countingWriter{Writer: writer}
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compThres := 1<<31 - 1 // compression disabled
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if compress {
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compThres = 128 // compress messages that are 128 bytes long or larger
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}
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c := rawConnection{
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id: deviceID,
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name: name,
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receiver: nativeModel{receiver},
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state: stateInitial,
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cr: cr,
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cw: cw,
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outbox: make(chan hdrMsg),
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nextID: make(chan int),
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closed: make(chan struct{}),
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compressionThreshold: compThres,
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}
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go c.readerLoop()
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go c.writerLoop()
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go c.pingerLoop()
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go c.idGenerator()
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return wireFormatConnection{&c}
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}
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func (c *rawConnection) ID() DeviceID {
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return c.id
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}
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func (c *rawConnection) Name() string {
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return c.name
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}
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// Index writes the list of file information to the connected peer device
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func (c *rawConnection) Index(folder string, idx []FileInfo) error {
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select {
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case <-c.closed:
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return ErrClosed
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default:
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}
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c.idxMut.Lock()
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c.send(-1, messageTypeIndex, IndexMessage{
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Folder: folder,
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Files: idx,
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})
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c.idxMut.Unlock()
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return nil
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}
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// IndexUpdate writes the list of file information to the connected peer device as an update
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func (c *rawConnection) IndexUpdate(folder string, idx []FileInfo) error {
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select {
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case <-c.closed:
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return ErrClosed
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default:
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}
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c.idxMut.Lock()
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c.send(-1, messageTypeIndexUpdate, IndexMessage{
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Folder: folder,
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Files: idx,
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})
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c.idxMut.Unlock()
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return nil
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}
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// Request returns the bytes for the specified block after fetching them from the connected peer.
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func (c *rawConnection) Request(folder string, name string, offset int64, size int) ([]byte, error) {
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var id int
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select {
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case id = <-c.nextID:
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case <-c.closed:
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return nil, ErrClosed
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}
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c.awaitingMut.Lock()
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if ch := c.awaiting[id]; ch != nil {
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panic("id taken")
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}
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rc := make(chan asyncResult, 1)
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c.awaiting[id] = rc
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c.awaitingMut.Unlock()
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ok := c.send(id, messageTypeRequest, RequestMessage{
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Folder: folder,
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Name: name,
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Offset: uint64(offset),
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Size: uint32(size),
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})
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if !ok {
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return nil, ErrClosed
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}
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res, ok := <-rc
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if !ok {
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return nil, ErrClosed
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}
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return res.val, res.err
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}
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// ClusterConfig send the cluster configuration message to the peer and returns any error
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func (c *rawConnection) ClusterConfig(config ClusterConfigMessage) {
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c.send(-1, messageTypeClusterConfig, config)
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}
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func (c *rawConnection) ping() bool {
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var id int
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select {
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case id = <-c.nextID:
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case <-c.closed:
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return false
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}
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rc := make(chan asyncResult, 1)
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c.awaitingMut.Lock()
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c.awaiting[id] = rc
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c.awaitingMut.Unlock()
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ok := c.send(id, messageTypePing, nil)
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if !ok {
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return false
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}
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res, ok := <-rc
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return ok && res.err == nil
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}
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func (c *rawConnection) readerLoop() (err error) {
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defer func() {
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c.close(err)
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}()
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for {
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select {
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case <-c.closed:
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return ErrClosed
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default:
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}
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hdr, msg, err := c.readMessage()
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if err != nil {
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return err
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}
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switch msg := msg.(type) {
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case IndexMessage:
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if msg.Flags != 0 {
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// We don't currently support or expect any flags.
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return fmt.Errorf("protocol error: unknown flags 0x%x in Index(Update) message", msg.Flags)
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}
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switch hdr.msgType {
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case messageTypeIndex:
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if c.state < stateCCRcvd {
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return fmt.Errorf("protocol error: index message in state %d", c.state)
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}
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c.handleIndex(msg)
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c.state = stateIdxRcvd
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case messageTypeIndexUpdate:
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if c.state < stateIdxRcvd {
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return fmt.Errorf("protocol error: index update message in state %d", c.state)
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}
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c.handleIndexUpdate(msg)
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}
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case RequestMessage:
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if msg.Flags != 0 {
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// We don't currently support or expect any flags.
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return fmt.Errorf("protocol error: unknown flags 0x%x in Request message", msg.Flags)
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}
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if c.state < stateIdxRcvd {
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return fmt.Errorf("protocol error: request message in state %d", c.state)
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}
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// Requests are handled asynchronously
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go c.handleRequest(hdr.msgID, msg)
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case ResponseMessage:
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if c.state < stateIdxRcvd {
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return fmt.Errorf("protocol error: response message in state %d", c.state)
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}
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c.handleResponse(hdr.msgID, msg)
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case pingMessage:
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c.send(hdr.msgID, messageTypePong, pongMessage{})
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case pongMessage:
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c.handlePong(hdr.msgID)
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case ClusterConfigMessage:
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if c.state != stateInitial {
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return fmt.Errorf("protocol error: cluster config message in state %d", c.state)
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}
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go c.receiver.ClusterConfig(c.id, msg)
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c.state = stateCCRcvd
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case CloseMessage:
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return errors.New(msg.Reason)
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default:
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return fmt.Errorf("protocol error: %s: unknown message type %#x", c.id, hdr.msgType)
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}
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}
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}
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func (c *rawConnection) readMessage() (hdr header, msg encodable, err error) {
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if cap(c.rdbuf0) < 8 {
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c.rdbuf0 = make([]byte, 8)
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} else {
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c.rdbuf0 = c.rdbuf0[:8]
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}
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_, err = io.ReadFull(c.cr, c.rdbuf0)
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if err != nil {
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return
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}
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hdr = decodeHeader(binary.BigEndian.Uint32(c.rdbuf0[0:4]))
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msglen := int(binary.BigEndian.Uint32(c.rdbuf0[4:8]))
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if debug {
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l.Debugf("read header %v (msglen=%d)", hdr, msglen)
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}
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if hdr.version != 0 {
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err = fmt.Errorf("unknown protocol version 0x%x", hdr.version)
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return
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}
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if cap(c.rdbuf0) < msglen {
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c.rdbuf0 = make([]byte, msglen)
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} else {
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c.rdbuf0 = c.rdbuf0[:msglen]
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}
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_, err = io.ReadFull(c.cr, c.rdbuf0)
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if err != nil {
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return
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}
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if debug {
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l.Debugf("read %d bytes", len(c.rdbuf0))
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}
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msgBuf := c.rdbuf0
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if hdr.compression {
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c.rdbuf1 = c.rdbuf1[:cap(c.rdbuf1)]
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c.rdbuf1, err = lz4.Decode(c.rdbuf1, c.rdbuf0)
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if err != nil {
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return
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}
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msgBuf = c.rdbuf1
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if debug {
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l.Debugf("decompressed to %d bytes", len(msgBuf))
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}
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}
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if debug {
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if len(msgBuf) > 1024 {
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l.Debugf("message data:\n%s", hex.Dump(msgBuf[:1024]))
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} else {
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l.Debugf("message data:\n%s", hex.Dump(msgBuf))
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}
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}
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// We check each returned error for the XDRError.IsEOF() method.
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// IsEOF()==true here means that the message contained fewer fields than
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// expected. It does not signify an EOF on the socket, because we've
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// successfully read a size value and that many bytes already. New fields
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// we expected but the other peer didn't send should be interpreted as
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// zero/nil, and if that's not valid we'll verify it somewhere else.
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switch hdr.msgType {
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case messageTypeIndex, messageTypeIndexUpdate:
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var idx IndexMessage
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err = idx.UnmarshalXDR(msgBuf)
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if xdrErr, ok := err.(isEofer); ok && xdrErr.IsEOF() {
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err = nil
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}
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msg = idx
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case messageTypeRequest:
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var req RequestMessage
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err = req.UnmarshalXDR(msgBuf)
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if xdrErr, ok := err.(isEofer); ok && xdrErr.IsEOF() {
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err = nil
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}
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msg = req
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case messageTypeResponse:
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var resp ResponseMessage
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err = resp.UnmarshalXDR(msgBuf)
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if xdrErr, ok := err.(isEofer); ok && xdrErr.IsEOF() {
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err = nil
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}
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msg = resp
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case messageTypePing:
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msg = pingMessage{}
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case messageTypePong:
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msg = pongMessage{}
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case messageTypeClusterConfig:
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var cc ClusterConfigMessage
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err = cc.UnmarshalXDR(msgBuf)
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if xdrErr, ok := err.(isEofer); ok && xdrErr.IsEOF() {
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err = nil
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}
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msg = cc
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case messageTypeClose:
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var cm CloseMessage
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err = cm.UnmarshalXDR(msgBuf)
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if xdrErr, ok := err.(isEofer); ok && xdrErr.IsEOF() {
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err = nil
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}
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msg = cm
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default:
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err = fmt.Errorf("protocol error: %s: unknown message type %#x", c.id, hdr.msgType)
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}
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return
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}
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func (c *rawConnection) handleIndex(im IndexMessage) {
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if debug {
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l.Debugf("Index(%v, %v, %d files)", c.id, im.Folder, len(im.Files))
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}
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c.receiver.Index(c.id, im.Folder, filterIndexMessageFiles(im.Files))
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}
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func (c *rawConnection) handleIndexUpdate(im IndexMessage) {
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if debug {
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l.Debugf("queueing IndexUpdate(%v, %v, %d files)", c.id, im.Folder, len(im.Files))
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}
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c.receiver.IndexUpdate(c.id, im.Folder, filterIndexMessageFiles(im.Files))
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}
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func filterIndexMessageFiles(fs []FileInfo) []FileInfo {
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var out []FileInfo
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for i, f := range fs {
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switch f.Name {
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case "", ".", "..", "/": // A few obviously invalid filenames
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l.Infof("Dropping invalid filename %q from incoming index", f.Name)
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if out == nil {
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// Most incoming updates won't contain anything invalid, so we
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// delay the allocation and copy to output slice until we
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// really need to do it, then copy all the so var valid files
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// to it.
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out = make([]FileInfo, i, len(fs)-1)
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copy(out, fs)
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}
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default:
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if out != nil {
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out = append(out, f)
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}
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}
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}
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if out != nil {
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return out
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}
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return fs
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}
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func (c *rawConnection) handleRequest(msgID int, req RequestMessage) {
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data, _ := c.receiver.Request(c.id, req.Folder, req.Name, int64(req.Offset), int(req.Size))
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c.send(msgID, messageTypeResponse, ResponseMessage{
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Data: data,
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})
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}
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func (c *rawConnection) handleResponse(msgID int, resp ResponseMessage) {
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c.awaitingMut.Lock()
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if rc := c.awaiting[msgID]; rc != nil {
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c.awaiting[msgID] = nil
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rc <- asyncResult{resp.Data, nil}
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close(rc)
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}
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c.awaitingMut.Unlock()
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}
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func (c *rawConnection) handlePong(msgID int) {
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c.awaitingMut.Lock()
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if rc := c.awaiting[msgID]; rc != nil {
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c.awaiting[msgID] = nil
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rc <- asyncResult{}
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close(rc)
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}
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c.awaitingMut.Unlock()
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}
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func (c *rawConnection) send(msgID int, msgType int, msg encodable) bool {
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if msgID < 0 {
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select {
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case id := <-c.nextID:
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msgID = id
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case <-c.closed:
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return false
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}
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}
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hdr := header{
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version: 0,
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msgID: msgID,
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msgType: msgType,
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}
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select {
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case c.outbox <- hdrMsg{hdr, msg}:
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return true
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case <-c.closed:
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return false
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}
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}
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|
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func (c *rawConnection) writerLoop() {
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var msgBuf = make([]byte, 8) // buffer for wire format message, kept and reused
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var uncBuf []byte // buffer for uncompressed message, kept and reused
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for {
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var tempBuf []byte
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var err error
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select {
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case hm := <-c.outbox:
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if hm.msg != nil {
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// Uncompressed message in uncBuf
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uncBuf, err = hm.msg.AppendXDR(uncBuf[:0])
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if err != nil {
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c.close(err)
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return
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}
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|
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if len(uncBuf) >= c.compressionThreshold {
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// Use compression for large messages
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hm.hdr.compression = true
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// Make sure we have enough space for the compressed message plus header in msgBug
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msgBuf = msgBuf[:cap(msgBuf)]
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if maxLen := lz4.CompressBound(len(uncBuf)) + 8; maxLen > len(msgBuf) {
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msgBuf = make([]byte, maxLen)
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}
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|
|
|
// Compressed is written to msgBuf, we keep tb for the length only
|
|
tempBuf, err = lz4.Encode(msgBuf[8:], uncBuf)
|
|
binary.BigEndian.PutUint32(msgBuf[4:8], uint32(len(tempBuf)))
|
|
msgBuf = msgBuf[0 : len(tempBuf)+8]
|
|
|
|
if debug {
|
|
l.Debugf("write compressed message; %v (len=%d)", hm.hdr, len(tempBuf))
|
|
}
|
|
} else {
|
|
// No point in compressing very short messages
|
|
hm.hdr.compression = false
|
|
|
|
msgBuf = msgBuf[:cap(msgBuf)]
|
|
if l := len(uncBuf) + 8; l > len(msgBuf) {
|
|
msgBuf = make([]byte, l)
|
|
}
|
|
|
|
binary.BigEndian.PutUint32(msgBuf[4:8], uint32(len(uncBuf)))
|
|
msgBuf = msgBuf[0 : len(uncBuf)+8]
|
|
copy(msgBuf[8:], uncBuf)
|
|
|
|
if debug {
|
|
l.Debugf("write uncompressed message; %v (len=%d)", hm.hdr, len(uncBuf))
|
|
}
|
|
}
|
|
} else {
|
|
if debug {
|
|
l.Debugf("write empty message; %v", hm.hdr)
|
|
}
|
|
binary.BigEndian.PutUint32(msgBuf[4:8], 0)
|
|
msgBuf = msgBuf[:8]
|
|
}
|
|
|
|
binary.BigEndian.PutUint32(msgBuf[0:4], encodeHeader(hm.hdr))
|
|
|
|
if err == nil {
|
|
var n int
|
|
n, err = c.cw.Write(msgBuf)
|
|
if debug {
|
|
l.Debugf("wrote %d bytes on the wire", n)
|
|
}
|
|
}
|
|
if err != nil {
|
|
c.close(err)
|
|
return
|
|
}
|
|
case <-c.closed:
|
|
return
|
|
}
|
|
}
|
|
}
|
|
|
|
func (c *rawConnection) close(err error) {
|
|
c.once.Do(func() {
|
|
close(c.closed)
|
|
|
|
c.awaitingMut.Lock()
|
|
for i, ch := range c.awaiting {
|
|
if ch != nil {
|
|
close(ch)
|
|
c.awaiting[i] = nil
|
|
}
|
|
}
|
|
c.awaitingMut.Unlock()
|
|
|
|
go c.receiver.Close(c.id, err)
|
|
})
|
|
}
|
|
|
|
func (c *rawConnection) idGenerator() {
|
|
nextID := 0
|
|
for {
|
|
nextID = (nextID + 1) & 0xfff
|
|
select {
|
|
case c.nextID <- nextID:
|
|
case <-c.closed:
|
|
return
|
|
}
|
|
}
|
|
}
|
|
|
|
func (c *rawConnection) pingerLoop() {
|
|
var rc = make(chan bool, 1)
|
|
ticker := time.Tick(pingIdleTime / 2)
|
|
for {
|
|
select {
|
|
case <-ticker:
|
|
if d := time.Since(c.cr.Last()); d < pingIdleTime {
|
|
if debug {
|
|
l.Debugln(c.id, "ping skipped after rd", d)
|
|
}
|
|
continue
|
|
}
|
|
if d := time.Since(c.cw.Last()); d < pingIdleTime {
|
|
if debug {
|
|
l.Debugln(c.id, "ping skipped after wr", d)
|
|
}
|
|
continue
|
|
}
|
|
go func() {
|
|
if debug {
|
|
l.Debugln(c.id, "ping ->")
|
|
}
|
|
rc <- c.ping()
|
|
}()
|
|
select {
|
|
case ok := <-rc:
|
|
if debug {
|
|
l.Debugln(c.id, "<- pong")
|
|
}
|
|
if !ok {
|
|
c.close(fmt.Errorf("ping failure"))
|
|
}
|
|
case <-time.After(pingTimeout):
|
|
c.close(fmt.Errorf("ping timeout"))
|
|
case <-c.closed:
|
|
return
|
|
}
|
|
|
|
case <-c.closed:
|
|
return
|
|
}
|
|
}
|
|
}
|
|
|
|
type Statistics struct {
|
|
At time.Time
|
|
InBytesTotal uint64
|
|
OutBytesTotal uint64
|
|
}
|
|
|
|
func (c *rawConnection) Statistics() Statistics {
|
|
return Statistics{
|
|
At: time.Now(),
|
|
InBytesTotal: c.cr.Tot(),
|
|
OutBytesTotal: c.cw.Tot(),
|
|
}
|
|
}
|