* all: Use context in lib/dialer * a bit slimmer * https://github.com/syncthing/syncthing/pull/5753 * bot * missed adding debug.go * errors.Cause * simultaneous dialing * anti-leak
263 lines
5.6 KiB
Go
263 lines
5.6 KiB
Go
// Copyright (C) 2015 Audrius Butkevicius and Contributors (see the CONTRIBUTORS file).
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package client
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import (
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"context"
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"crypto/tls"
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"fmt"
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"net"
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"net/url"
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"time"
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"github.com/pkg/errors"
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"github.com/syncthing/syncthing/lib/dialer"
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syncthingprotocol "github.com/syncthing/syncthing/lib/protocol"
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"github.com/syncthing/syncthing/lib/relay/protocol"
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)
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type staticClient struct {
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commonClient
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uri *url.URL
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config *tls.Config
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messageTimeout time.Duration
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connectTimeout time.Duration
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conn *tls.Conn
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connected bool
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latency time.Duration
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}
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func newStaticClient(uri *url.URL, certs []tls.Certificate, invitations chan protocol.SessionInvitation, timeout time.Duration) RelayClient {
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c := &staticClient{
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uri: uri,
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config: configForCerts(certs),
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messageTimeout: time.Minute * 2,
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connectTimeout: timeout,
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}
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c.commonClient = newCommonClient(invitations, c.serve, c.String())
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return c
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}
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func (c *staticClient) serve(ctx context.Context) error {
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if err := c.connect(ctx); err != nil {
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l.Infof("Could not connect to relay %s: %s", c.uri, err)
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return err
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}
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l.Debugln(c, "connected", c.conn.RemoteAddr())
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defer c.disconnect()
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if err := c.join(); err != nil {
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l.Infof("Could not join relay %s: %s", c.uri, err)
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return err
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}
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if err := c.conn.SetDeadline(time.Time{}); err != nil {
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l.Infoln("Relay set deadline:", err)
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return err
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}
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l.Infof("Joined relay %s://%s", c.uri.Scheme, c.uri.Host)
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defer l.Infof("Disconnected from relay %s://%s", c.uri.Scheme, c.uri.Host)
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c.mut.Lock()
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c.connected = true
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c.mut.Unlock()
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messages := make(chan interface{})
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errors := make(chan error, 1)
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go messageReader(ctx, c.conn, messages, errors)
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timeout := time.NewTimer(c.messageTimeout)
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for {
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select {
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case message := <-messages:
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timeout.Reset(c.messageTimeout)
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l.Debugf("%s received message %T", c, message)
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switch msg := message.(type) {
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case protocol.Ping:
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if err := protocol.WriteMessage(c.conn, protocol.Pong{}); err != nil {
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l.Infoln("Relay write:", err)
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return err
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}
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l.Debugln(c, "sent pong")
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case protocol.SessionInvitation:
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ip := net.IP(msg.Address)
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if len(ip) == 0 || ip.IsUnspecified() {
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msg.Address = remoteIPBytes(c.conn)
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}
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c.invitations <- msg
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case protocol.RelayFull:
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l.Infof("Disconnected from relay %s due to it becoming full.", c.uri)
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return fmt.Errorf("relay full")
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default:
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l.Infoln("Relay: protocol error: unexpected message %v", msg)
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return fmt.Errorf("protocol error: unexpected message %v", msg)
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}
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case <-ctx.Done():
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l.Debugln(c, "stopping")
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return nil
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case err := <-errors:
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l.Infof("Disconnecting from relay %s due to error: %s", c.uri, err)
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return err
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case <-timeout.C:
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l.Debugln(c, "timed out")
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return fmt.Errorf("timed out")
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}
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}
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}
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func (c *staticClient) StatusOK() bool {
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c.mut.RLock()
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con := c.connected
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c.mut.RUnlock()
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return con
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}
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func (c *staticClient) Latency() time.Duration {
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c.mut.RLock()
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lat := c.latency
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c.mut.RUnlock()
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return lat
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}
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func (c *staticClient) String() string {
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return fmt.Sprintf("StaticClient:%p@%s", c, c.URI())
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}
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func (c *staticClient) URI() *url.URL {
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return c.uri
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}
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func (c *staticClient) connect(ctx context.Context) error {
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if c.uri.Scheme != "relay" {
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return fmt.Errorf("unsupported relay scheme: %v", c.uri.Scheme)
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}
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t0 := time.Now()
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timeoutCtx, cancel := context.WithTimeout(ctx, time.Second)
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defer cancel()
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tcpConn, err := dialer.DialContext(timeoutCtx, "tcp", c.uri.Host)
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if err != nil {
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return err
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}
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c.mut.Lock()
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c.latency = time.Since(t0)
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c.mut.Unlock()
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conn := tls.Client(tcpConn, c.config)
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if err := conn.SetDeadline(time.Now().Add(c.connectTimeout)); err != nil {
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conn.Close()
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return err
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}
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if err := performHandshakeAndValidation(conn, c.uri); err != nil {
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conn.Close()
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return err
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}
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c.conn = conn
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return nil
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}
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func (c *staticClient) disconnect() {
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l.Debugln(c, "disconnecting")
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c.mut.Lock()
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c.connected = false
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c.mut.Unlock()
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c.conn.Close()
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}
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func (c *staticClient) join() error {
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if err := protocol.WriteMessage(c.conn, protocol.JoinRelayRequest{}); err != nil {
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return err
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}
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message, err := protocol.ReadMessage(c.conn)
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if err != nil {
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return err
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}
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switch msg := message.(type) {
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case protocol.Response:
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if msg.Code != 0 {
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return fmt.Errorf("incorrect response code %d: %s", msg.Code, msg.Message)
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}
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case protocol.RelayFull:
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return fmt.Errorf("relay full")
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default:
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return fmt.Errorf("protocol error: expecting response got %v", msg)
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}
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return nil
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}
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func performHandshakeAndValidation(conn *tls.Conn, uri *url.URL) error {
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if err := conn.Handshake(); err != nil {
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return err
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}
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cs := conn.ConnectionState()
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if !cs.NegotiatedProtocolIsMutual || cs.NegotiatedProtocol != protocol.ProtocolName {
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return fmt.Errorf("protocol negotiation error")
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}
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q := uri.Query()
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relayIDs := q.Get("id")
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if relayIDs != "" {
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relayID, err := syncthingprotocol.DeviceIDFromString(relayIDs)
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if err != nil {
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return errors.Wrap(err, "relay address contains invalid verification id")
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}
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certs := cs.PeerCertificates
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if cl := len(certs); cl != 1 {
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return fmt.Errorf("unexpected certificate count: %d", cl)
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}
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remoteID := syncthingprotocol.NewDeviceID(certs[0].Raw)
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if remoteID != relayID {
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return fmt.Errorf("relay id does not match. Expected %v got %v", relayID, remoteID)
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}
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}
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return nil
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}
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func messageReader(ctx context.Context, conn net.Conn, messages chan<- interface{}, errors chan<- error) {
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for {
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msg, err := protocol.ReadMessage(conn)
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if err != nil {
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errors <- err
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return
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}
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select {
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case messages <- msg:
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case <-ctx.Done():
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return
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}
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}
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}
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