446 lines
8.8 KiB
Go
446 lines
8.8 KiB
Go
package protocol
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import (
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"compress/flate"
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"errors"
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"fmt"
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"io"
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"log"
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"sync"
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"time"
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"github.com/calmh/syncthing/buffers"
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"github.com/calmh/syncthing/xdr"
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)
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const BlockSize = 128 * 1024
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const (
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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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messageTypeOptions = 7
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)
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const (
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FlagDeleted = 1 << 12
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FlagInvalid = 1 << 13
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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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)
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type Model interface {
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// An index was received from the peer node
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Index(nodeID string, files []FileInfo)
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// An index update was received from the peer node
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IndexUpdate(nodeID string, files []FileInfo)
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// A request was made by the peer node
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Request(nodeID, repo string, name string, offset int64, size int) ([]byte, error)
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// The peer node closed the connection
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Close(nodeID string, err error)
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}
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type Connection struct {
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sync.RWMutex
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id string
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receiver Model
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reader io.Reader
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xr *xdr.Reader
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writer io.Writer
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xw *xdr.Writer
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closed bool
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awaiting map[int]chan asyncResult
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nextId int
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indexSent map[string]map[string][2]int64
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peerOptions map[string]string
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myOptions map[string]string
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optionsLock sync.Mutex
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hasSentIndex bool
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hasRecvdIndex bool
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statisticsLock sync.Mutex
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}
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var ErrClosed = errors.New("Connection closed")
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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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const (
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pingTimeout = 2 * time.Minute
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pingIdleTime = 5 * time.Minute
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)
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func NewConnection(nodeID string, reader io.Reader, writer io.Writer, receiver Model, options map[string]string) *Connection {
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flrd := flate.NewReader(reader)
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flwr, err := flate.NewWriter(writer, flate.BestSpeed)
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if err != nil {
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panic(err)
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}
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c := Connection{
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id: nodeID,
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receiver: receiver,
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reader: flrd,
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xr: xdr.NewReader(flrd),
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writer: flwr,
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xw: xdr.NewWriter(flwr),
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awaiting: make(map[int]chan asyncResult),
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indexSent: make(map[string]map[string][2]int64),
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}
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go c.readerLoop()
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go c.pingerLoop()
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if options != nil {
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c.myOptions = options
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go func() {
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c.Lock()
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header{0, c.nextId, messageTypeOptions}.encodeXDR(c.xw)
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var om OptionsMessage
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for k, v := range options {
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om.Options = append(om.Options, Option{k, v})
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}
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om.encodeXDR(c.xw)
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err := c.xw.Error()
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if err == nil {
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err = c.flush()
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}
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if err != nil {
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log.Println("Warning: Write error during initial handshake:", err)
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}
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c.nextId++
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c.Unlock()
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}()
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}
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return &c
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}
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func (c *Connection) ID() string {
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return c.id
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}
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// Index writes the list of file information to the connected peer node
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func (c *Connection) Index(repo string, idx []FileInfo) {
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c.Lock()
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var msgType int
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if c.indexSent[repo] == nil {
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// This is the first time we send an index.
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msgType = messageTypeIndex
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c.indexSent[repo] = make(map[string][2]int64)
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for _, f := range idx {
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c.indexSent[repo][f.Name] = [2]int64{f.Modified, int64(f.Version)}
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}
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} else {
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// We have sent one full index. Only send updates now.
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msgType = messageTypeIndexUpdate
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var diff []FileInfo
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for _, f := range idx {
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if vs, ok := c.indexSent[repo][f.Name]; !ok || f.Modified != vs[0] || int64(f.Version) != vs[1] {
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diff = append(diff, f)
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c.indexSent[repo][f.Name] = [2]int64{f.Modified, int64(f.Version)}
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}
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}
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idx = diff
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}
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header{0, c.nextId, msgType}.encodeXDR(c.xw)
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_, err := IndexMessage{repo, idx}.encodeXDR(c.xw)
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if err == nil {
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err = c.flush()
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}
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c.nextId = (c.nextId + 1) & 0xfff
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c.hasSentIndex = true
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c.Unlock()
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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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// Request returns the bytes for the specified block after fetching them from the connected peer.
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func (c *Connection) Request(repo string, name string, offset int64, size int) ([]byte, error) {
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c.Lock()
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if c.closed {
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c.Unlock()
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return nil, ErrClosed
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}
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rc := make(chan asyncResult)
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c.awaiting[c.nextId] = rc
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header{0, c.nextId, messageTypeRequest}.encodeXDR(c.xw)
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_, err := RequestMessage{repo, name, uint64(offset), uint32(size)}.encodeXDR(c.xw)
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if err == nil {
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err = c.flush()
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}
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if err != nil {
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c.Unlock()
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c.close(err)
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return nil, err
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}
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c.nextId = (c.nextId + 1) & 0xfff
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c.Unlock()
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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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func (c *Connection) ping() bool {
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c.Lock()
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if c.closed {
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c.Unlock()
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return false
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}
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rc := make(chan asyncResult, 1)
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c.awaiting[c.nextId] = rc
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header{0, c.nextId, messageTypePing}.encodeXDR(c.xw)
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err := c.flush()
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if err != nil {
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c.Unlock()
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c.close(err)
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return false
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} else if c.xw.Error() != nil {
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c.Unlock()
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c.close(c.xw.Error())
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return false
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}
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c.nextId = (c.nextId + 1) & 0xfff
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c.Unlock()
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res, ok := <-rc
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return ok && res.err == nil
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}
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type flusher interface {
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Flush() error
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}
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func (c *Connection) flush() error {
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if f, ok := c.writer.(flusher); ok {
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return f.Flush()
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}
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return nil
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}
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func (c *Connection) close(err error) {
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c.Lock()
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if c.closed {
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c.Unlock()
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return
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}
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c.closed = true
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for _, ch := range c.awaiting {
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close(ch)
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}
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c.awaiting = nil
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c.Unlock()
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c.receiver.Close(c.id, err)
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}
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func (c *Connection) isClosed() bool {
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c.RLock()
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defer c.RUnlock()
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return c.closed
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}
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func (c *Connection) readerLoop() {
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loop:
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for {
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var hdr header
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hdr.decodeXDR(c.xr)
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if c.xr.Error() != nil {
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c.close(c.xr.Error())
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break loop
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}
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if hdr.version != 0 {
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c.close(fmt.Errorf("Protocol error: %s: unknown message version %#x", c.id, hdr.version))
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break loop
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}
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switch hdr.msgType {
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case messageTypeIndex:
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var im IndexMessage
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im.decodeXDR(c.xr)
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if c.xr.Error() != nil {
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c.close(c.xr.Error())
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break loop
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} else {
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c.receiver.Index(c.id, im.Files)
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}
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c.Lock()
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c.hasRecvdIndex = true
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c.Unlock()
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case messageTypeIndexUpdate:
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var im IndexMessage
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im.decodeXDR(c.xr)
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if c.xr.Error() != nil {
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c.close(c.xr.Error())
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break loop
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} else {
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c.receiver.IndexUpdate(c.id, im.Files)
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}
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case messageTypeRequest:
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var req RequestMessage
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req.decodeXDR(c.xr)
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if c.xr.Error() != nil {
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c.close(c.xr.Error())
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break loop
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}
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go c.processRequest(hdr.msgID, req)
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case messageTypeResponse:
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data := c.xr.ReadBytesMax(256 * 1024) // Sufficiently larger than max expected block size
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if c.xr.Error() != nil {
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c.close(c.xr.Error())
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break loop
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}
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c.Lock()
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rc, ok := c.awaiting[hdr.msgID]
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delete(c.awaiting, hdr.msgID)
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c.Unlock()
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if ok {
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rc <- asyncResult{data, c.xr.Error()}
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close(rc)
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}
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case messageTypePing:
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c.Lock()
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header{0, hdr.msgID, messageTypePong}.encodeXDR(c.xw)
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err := c.flush()
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c.Unlock()
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if err != nil {
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c.close(err)
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break loop
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} else if c.xw.Error() != nil {
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c.close(c.xw.Error())
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break loop
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}
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case messageTypePong:
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c.RLock()
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rc, ok := c.awaiting[hdr.msgID]
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c.RUnlock()
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if ok {
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rc <- asyncResult{}
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close(rc)
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c.Lock()
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delete(c.awaiting, hdr.msgID)
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c.Unlock()
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}
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case messageTypeOptions:
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var om OptionsMessage
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om.decodeXDR(c.xr)
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if c.xr.Error() != nil {
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c.close(c.xr.Error())
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break loop
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}
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c.optionsLock.Lock()
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c.peerOptions = make(map[string]string, len(om.Options))
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for _, opt := range om.Options {
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c.peerOptions[opt.Key] = opt.Value
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}
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c.optionsLock.Unlock()
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if mh, rh := c.myOptions["clusterHash"], c.peerOptions["clusterHash"]; len(mh) > 0 && len(rh) > 0 && mh != rh {
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c.close(ErrClusterHash)
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break loop
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}
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default:
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c.close(fmt.Errorf("Protocol error: %s: unknown message type %#x", c.id, hdr.msgType))
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break loop
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}
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}
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}
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func (c *Connection) processRequest(msgID int, req RequestMessage) {
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data, _ := c.receiver.Request(c.id, req.Repository, req.Name, int64(req.Offset), int(req.Size))
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c.Lock()
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header{0, msgID, messageTypeResponse}.encodeXDR(c.xw)
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_, err := c.xw.WriteBytes(data)
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if err == nil {
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err = c.flush()
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}
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c.Unlock()
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buffers.Put(data)
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if err != nil {
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c.close(err)
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}
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}
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func (c *Connection) pingerLoop() {
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var rc = make(chan bool, 1)
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for {
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time.Sleep(pingIdleTime / 2)
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c.RLock()
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ready := c.hasRecvdIndex && c.hasSentIndex
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c.RUnlock()
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if ready {
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go func() {
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rc <- c.ping()
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}()
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select {
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case ok := <-rc:
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if !ok {
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c.close(fmt.Errorf("Ping failure"))
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}
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case <-time.After(pingTimeout):
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c.close(fmt.Errorf("Ping timeout"))
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}
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}
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}
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}
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type Statistics struct {
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At time.Time
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InBytesTotal int
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OutBytesTotal int
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}
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func (c *Connection) Statistics() Statistics {
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c.statisticsLock.Lock()
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defer c.statisticsLock.Unlock()
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stats := Statistics{
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At: time.Now(),
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InBytesTotal: int(c.xr.Tot()),
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OutBytesTotal: int(c.xw.Tot()),
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}
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return stats
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}
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func (c *Connection) Option(key string) string {
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c.optionsLock.Lock()
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defer c.optionsLock.Unlock()
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return c.peerOptions[key]
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}
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