Golang Conn.Close方法代码示例

//DialClient returns two channels where one returns a ssh.Client and the other and error
func DialClient(dial, expire time.Duration, ip string, conf *ssh.ClientConfig, retry <-chan struct{}) (*ssh.Client, error) {

	flux.Report(nil, fmt.Sprintf("MakeDial for %s for dailing at %+s and expiring in %+s", conf.User, dial, expire))

	cons := make(chan *ssh.Client)
	errs := make(chan error)

	var con net.Conn
	var sc ssh.Conn
	var chans <-chan ssh.NewChannel
	var req <-chan *ssh.Request
	var err error

	flux.GoDefer("MakeDial", func() {
		con, err = net.DialTimeout("tcp", ip, dial)

		if err != nil {
			flux.Report(err, fmt.Sprintf("MakeDial:Before for %s net.DailTimeout", ip))
			errs <- err
			return
		}

		sc, chans, req, err = ssh.NewClientConn(con, ip, conf)

		if err != nil {
			flux.Report(err, fmt.Sprintf("MakeDial:After for %s ssh.NewClientConn", ip))
			errs <- err
			return
		}

		flux.Report(nil, fmt.Sprintf("MakeDial initiating NewClient for %s", ip))
		cons <- ssh.NewClient(sc, chans, req)
		return
	})

	expiration := threshold(expire)

	go func() {
		for _ = range retry {
			expiration = threshold(expire)
		}
	}()

	select {
	case err := <-errs:
		flux.Report(err, fmt.Sprintf("NewClient Ending!"))
		return nil, err
	case som := <-cons:
		flux.Report(nil, fmt.Sprintf("NewClient Created!"))
		expiration = nil
		return som, nil
	case <-expiration:
		flux.Report(nil, fmt.Sprintf("MakeDial Expired for %s!", ip))
		defer con.Close()
		if sc != nil {
			sc.Close()
		}
		return nil, ErrTimeout
	}
}

func ProxyChannels(logger lager.Logger, conn ssh.Conn, channels <-chan ssh.NewChannel) {
	logger = logger.Session("proxy-channels")

	logger.Info("started")
	defer logger.Info("completed")
	defer conn.Close()

	for newChannel := range channels {
		logger.Info("new-channel", lager.Data{
			"channelType": newChannel.ChannelType(),
			"extraData":   newChannel.ExtraData(),
		})

		targetChan, targetReqs, err := conn.OpenChannel(newChannel.ChannelType(), newChannel.ExtraData())
		if err != nil {
			logger.Error("failed-to-open-channel", err)
			if openErr, ok := err.(*ssh.OpenChannelError); ok {
				newChannel.Reject(openErr.Reason, openErr.Message)
			} else {
				newChannel.Reject(ssh.ConnectionFailed, err.Error())
			}
			continue
		}

		sourceChan, sourceReqs, err := newChannel.Accept()
		if err != nil {
			targetChan.Close()
			continue
		}

		toTargetLogger := logger.Session("to-target")
		toSourceLogger := logger.Session("to-source")

		go func() {
			helpers.Copy(toTargetLogger, nil, targetChan, sourceChan)
			targetChan.CloseWrite()
		}()
		go func() {
			helpers.Copy(toSourceLogger, nil, sourceChan, targetChan)
			sourceChan.CloseWrite()
		}()

		go ProxyRequests(toTargetLogger, newChannel.ChannelType(), sourceReqs, targetChan)
		go ProxyRequests(toSourceLogger, newChannel.ChannelType(), targetReqs, sourceChan)
	}
}

/* handleConnRequests handles proxying requests read from reqs to the SSH
connection sc.  info is used for logging */
func handleConnRequests(
	reqs <-chan *ssh.Request,
	c ssh.Conn,
	info string,
) {
	for r := range reqs {
		go handleRequest(
			r,
			func(
				name string,
				wantReply bool,
				payload []byte,
			) (bool, []byte, error) {
				return c.SendRequest(name, wantReply, payload)
			},
			func() error { return c.Close() },
			info,
		)
	}
}

func (c *comm) reconnect() (err error) {
	if c.conn != nil {
		c.conn.Close()
	}

	// Set the conn and client to nil since we'll recreate it
	c.conn = nil
	c.client = nil

	log.Printf("reconnecting to TCP connection for SSH")
	c.conn, err = c.config.Connection()
	if err != nil {
		// Explicitly set this to the REAL nil. Connection() can return
		// a nil implementation of net.Conn which will make the
		// "if c.conn == nil" check fail above. Read here for more information
		// on this psychotic language feature:
		//
		// http://golang.org/doc/faq#nil_error
		c.conn = nil

		log.Printf("reconnection error: %s", err)
		return
	}

	log.Printf("handshaking with SSH")

	// Default timeout to 1 minute if it wasn't specified (zero value). For
	// when you need to handshake from low orbit.
	var duration time.Duration
	if c.config.HandshakeTimeout == 0 {
		duration = 1 * time.Minute
	} else {
		duration = c.config.HandshakeTimeout
	}

	connectionEstablished := make(chan struct{}, 1)

	var sshConn ssh.Conn
	var sshChan <-chan ssh.NewChannel
	var req <-chan *ssh.Request

	go func() {
		sshConn, sshChan, req, err = ssh.NewClientConn(c.conn, c.address, c.config.SSHConfig)
		close(connectionEstablished)
	}()

	select {
	case <-connectionEstablished:
		// We don't need to do anything here. We just want select to block until
		// we connect or timeout.
	case <-time.After(duration):
		if c.conn != nil {
			c.conn.Close()
		}
		if sshConn != nil {
			sshConn.Close()
		}
		return ErrHandshakeTimeout
	}

	if err != nil {
		log.Printf("handshake error: %s", err)
		return
	}
	log.Printf("handshake complete!")
	if sshConn != nil {
		c.client = ssh.NewClient(sshConn, sshChan, req)
	}
	c.connectToAgent()

	return
}