croc/src/client.go

package croc

import (
	"net"
	"net/url"
	"os"
	"os/signal"
	"sync"
	"time"

	log "github.com/cihub/seelog"
	"github.com/gorilla/websocket"
	"github.com/pkg/errors"
	"github.com/schollz/croc/src/pake"
)

func (c *Croc) client(role int, codePhrase string) (err error) {
	defer log.Flush()

	// initialize the channel data for this client
	c.cs.Lock()

	c.cs.channel.codePhrase = codePhrase
	if len(codePhrase) > 0 {
		if len(codePhrase) < 4 {
			err = errors.New("code phrase must be more than 4 characters")
			return
		}
		c.cs.channel.Channel = codePhrase[:3]
		c.cs.channel.passPhrase = codePhrase[3:]
	} else {
		// TODO
		// generate code phrase
		c.cs.channel.Channel = "chou"
		c.cs.channel.passPhrase = codePhrase[3:]
	}
	channel := c.cs.channel.Channel
	c.cs.Unlock()

	interrupt := make(chan os.Signal, 1)
	signal.Notify(interrupt, os.Interrupt)

	// connect to the websocket
	// TODO:
	// use predefined host and HTTPS, if exists
	u := url.URL{Scheme: "ws", Host: "localhost:8003", Path: "/"}
	log.Debugf("connecting to %s", u.String())
	ws, _, err := websocket.DefaultDialer.Dial(u.String(), nil)
	if err != nil {
		log.Error("dial:", err)
		return
	}
	defer ws.Close()

	// read in the messages and process them
	done := make(chan struct{})
	go func() {
		defer close(done)
		for {
			var cd channelData
			err := ws.ReadJSON(&cd)
			if err != nil {
				log.Debugf("sender read error:", err)
				return
			}
			log.Debugf("recv: %s", cd)
			err = c.processState(ws, cd)
			if err != nil {
				log.Warn(err)
				return
			}
		}
	}()

	// initialize by joining as corresponding role
	// TODO:
	// allowing suggesting a channel
	p := channelData{
		Open:    true,
		Role:    role,
		Channel: channel,
	}
	log.Debugf("sending opening payload: %+v", p)
	err = ws.WriteJSON(p)
	if err != nil {
		log.Errorf("problem opening: %s", err.Error())
		return
	}

	var wg sync.WaitGroup
	wg.Add(1)
	go func(wg *sync.WaitGroup) {
		defer wg.Done()
		for {
			select {
			case <-done:
				return
			case <-interrupt:
				// send Close signal to relay on interrupt
				log.Debugf("interrupt")
				c.cs.Lock()
				channel := c.cs.channel.Channel
				uuid := c.cs.channel.UUID
				c.cs.Unlock()
				// Cleanly close the connection by sending a close message and then
				// waiting (with timeout) for the server to close the connection.
				log.Debug("sending close signal")
				errWrite := ws.WriteJSON(channelData{
					Channel: channel,
					UUID:    uuid,
					Close:   true,
				})
				if errWrite != nil {
					log.Debugf("write close:", err)
					return
				}
				select {
				case <-done:
				case <-time.After(time.Second):
				}
				return
			}
		}
	}(&wg)
	wg.Wait()

	c.cs.Lock()
	if c.cs.channel.FileReceived {
		log.Info("file recieved!")
	}
	c.cs.Unlock()
	return
}

func (c *Croc) processState(ws *websocket.Conn, cd channelData) (err error) {
	c.cs.Lock()
	defer c.cs.Unlock()

	// first check if there is relay reported error
	if cd.Error != "" {
		err = errors.New(cd.Error)
		return
	}
	// TODO:
	// check if the state is not aligned (i.e. have h(k) but no hh(k))
	// throw error if not aligned so it can exit

	// if file received, then you are all done
	if cd.FileReceived {
		c.cs.channel.FileReceived = true
		log.Debug("file recieved!")
		log.Debug("sending close signal")
		c.cs.channel.Close = true
		ws.WriteJSON(c.cs.channel)
		return
	}

	// if transfer ready then send file
	if cd.TransferReady {
		c.cs.channel.TransferReady = true
		return
	}

	// first update the channel data
	// initialize if has UUID
	if cd.UUID != "" {
		c.cs.channel.UUID = cd.UUID
		c.cs.channel.Channel = cd.Channel
		c.cs.channel.Role = cd.Role
		c.cs.channel.Curve = cd.Curve
		c.cs.channel.Pake, err = pake.Init([]byte(c.cs.channel.passPhrase), cd.Role, getCurve(cd.Curve))
		c.cs.channel.Update = true
		log.Debugf("updating channel")
		errWrite := ws.WriteJSON(c.cs.channel)
		if errWrite != nil {
			log.Error(errWrite)
		}
		c.cs.channel.Update = false
		log.Debugf("initialized client state")
		return
	}
	// copy over the rest of the state
	c.cs.channel.Ports = cd.Ports

	// update the Pake
	if cd.Pake != nil && cd.Pake.Role != c.cs.channel.Role {
		log.Debugf("updating pake from %d", cd.Pake.Role)
		if c.cs.channel.Pake.HkA == nil {
			err = c.cs.channel.Pake.Update(cd.Pake.Bytes())
			if err != nil {
				log.Error(err)
				log.Debug("sending close signal")
				c.cs.channel.Close = true
				c.cs.channel.Error = err.Error()
				ws.WriteJSON(c.cs.channel)
				return
			}
			c.cs.channel.Update = true
			log.Debugf("updating channel")
			errWrite := ws.WriteJSON(c.cs.channel)
			if errWrite != nil {
				log.Error(errWrite)
			}
			c.cs.channel.Update = false
		}
	}
	if c.cs.channel.Role == 0 && c.cs.channel.Pake.IsVerified() {
		go func() {
			// encrypt the files
			// TODO
			c.cs.Lock()
			c.cs.channel.fileReady = true
			c.cs.Unlock()
		}()
	}

	// TODO
	// process the client state
	if c.cs.channel.Pake.IsVerified() && !c.cs.channel.isReady {
		// spawn TCP connections
		c.cs.channel.isReady = true
		go func(role int) {
			err = c.dialUp()
			if err == nil {
				if role == 1 {
					c.cs.Lock()
					c.cs.channel.Update = true
					c.cs.channel.FileReceived = true
					log.Debugf("got file successfully")
					errWrite := ws.WriteJSON(c.cs.channel)
					if errWrite != nil {
						log.Error(errWrite)
					}
					c.cs.channel.Update = false
					c.cs.Unlock()
				}
			} else {
				log.Error(err)
			}
		}(c.cs.channel.Role)
	}
	return
}

func (c *Croc) dialUp() (err error) {
	c.cs.Lock()
	ports := c.cs.channel.Ports
	channel := c.cs.channel.Channel
	uuid := c.cs.channel.UUID
	role := c.cs.channel.Role
	c.cs.Unlock()
	errorChan := make(chan error)
	for i, port := range ports {
		go func(channel, uuid, port string, i int) {
			if i == 0 {
				log.Debug("dialing up")
			}
			log.Debugf("connecting to %s", "localhost:"+port)
			connection, err := net.Dial("tcp", "localhost:"+port)
			if err != nil {
				errorChan <- err
				return
			}
			defer connection.Close()
			connection.SetReadDeadline(time.Now().Add(1 * time.Hour))
			connection.SetDeadline(time.Now().Add(1 * time.Hour))
			connection.SetWriteDeadline(time.Now().Add(1 * time.Hour))
			message, err := receiveMessage(connection)
			if err != nil {
				errorChan <- err
				return
			}
			log.Debugf("relay says: %s", message)
			err = sendMessage(channel, connection)
			if err != nil {
				errorChan <- err
				return
			}
			err = sendMessage(uuid, connection)
			if err != nil {
				errorChan <- err
				return
			}

			// wait for transfer to be ready
			for {
				c.cs.RLock()
				ready := c.cs.channel.TransferReady
				if role == 0 {
					ready = ready && c.cs.channel.fileReady
				}
				c.cs.RUnlock()
				if ready {
					break
				}
				time.Sleep(10 * time.Millisecond)
			}
			if role == 0 {
				log.Debug("send file")
			} else {
				log.Debug("receive file")
			}
			time.Sleep(3 * time.Second)
			errorChan <- nil
		}(channel, uuid, port, i)
	}

	// collect errors
	for i := 0; i < len(ports); i++ {
		errOne := <-errorChan
		if errOne != nil {
			log.Warn(errOne)
		}
	}
	return
}