mirror of https://github.com/schollz/croc.git
501 lines
10 KiB
Go
501 lines
10 KiB
Go
package tcp
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import (
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"bytes"
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"fmt"
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"net"
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"strings"
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"sync"
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"time"
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log "github.com/schollz/logger"
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"github.com/schollz/pake/v3"
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"github.com/schollz/croc/v9/src/comm"
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"github.com/schollz/croc/v9/src/crypt"
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"github.com/schollz/croc/v9/src/models"
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)
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type server struct {
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port string
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debugLevel string
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banner string
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password string
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rooms roomMap
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}
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type roomInfo struct {
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first *comm.Comm
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second *comm.Comm
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opened time.Time
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full bool
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}
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type roomMap struct {
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rooms map[string]roomInfo
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sync.Mutex
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}
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var timeToRoomDeletion = 10 * time.Minute
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var pingRoom = "pinglkasjdlfjsaldjf"
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// Run starts a tcp listener, run async
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func Run(debugLevel, port, password string, banner ...string) (err error) {
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s := new(server)
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s.port = port
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s.password = password
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s.debugLevel = debugLevel
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if len(banner) > 0 {
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s.banner = banner[0]
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}
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return s.start()
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}
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func (s *server) start() (err error) {
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log.SetLevel(s.debugLevel)
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log.Debugf("starting with password '%s'", s.password)
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s.rooms.Lock()
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s.rooms.rooms = make(map[string]roomInfo)
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s.rooms.Unlock()
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// delete old rooms
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go func() {
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for {
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time.Sleep(timeToRoomDeletion)
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var roomsToDelete []string
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s.rooms.Lock()
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for room := range s.rooms.rooms {
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if time.Since(s.rooms.rooms[room].opened) > 3*time.Hour {
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roomsToDelete = append(roomsToDelete, room)
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}
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}
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s.rooms.Unlock()
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for _, room := range roomsToDelete {
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s.deleteRoom(room)
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}
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}
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}()
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err = s.run()
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if err != nil {
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log.Error(err)
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}
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return
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}
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func (s *server) run() (err error) {
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log.Infof("starting TCP server on " + s.port)
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server, err := net.Listen("tcp", ":"+s.port)
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if err != nil {
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return fmt.Errorf("error listening on %s: %w", s.port, err)
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}
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defer server.Close()
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// spawn a new goroutine whenever a client connects
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for {
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connection, err := server.Accept()
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if err != nil {
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return fmt.Errorf("problem accepting connection: %w", err)
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}
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log.Debugf("client %s connected", connection.RemoteAddr().String())
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go func(port string, connection net.Conn) {
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c := comm.New(connection)
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room, errCommunication := s.clientCommunication(port, c)
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log.Debugf("room: %+v", room)
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log.Debugf("err: %+v", errCommunication)
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if errCommunication != nil {
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log.Debugf("relay-%s: %s", connection.RemoteAddr().String(), errCommunication.Error())
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connection.Close()
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return
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}
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if room == pingRoom {
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log.Debugf("got ping")
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connection.Close()
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return
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}
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for {
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// check connection
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log.Debugf("checking connection of room %s for %+v", room, c)
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deleteIt := false
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s.rooms.Lock()
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if _, ok := s.rooms.rooms[room]; !ok {
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log.Debug("room is gone")
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s.rooms.Unlock()
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return
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}
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log.Debugf("room: %+v", s.rooms.rooms[room])
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if s.rooms.rooms[room].first != nil && s.rooms.rooms[room].second != nil {
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log.Debug("rooms ready")
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s.rooms.Unlock()
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break
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} else {
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if s.rooms.rooms[room].first != nil {
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errSend := s.rooms.rooms[room].first.Send([]byte{1})
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if errSend != nil {
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log.Debug(errSend)
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deleteIt = true
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}
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}
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}
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s.rooms.Unlock()
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if deleteIt {
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s.deleteRoom(room)
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break
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}
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time.Sleep(1 * time.Second)
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}
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}(s.port, connection)
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}
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}
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var weakKey = []byte{1, 2, 3}
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func (s *server) clientCommunication(port string, c *comm.Comm) (room string, err error) {
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// establish secure password with PAKE for communication with relay
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B, err := pake.InitCurve(weakKey, 1, "siec")
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if err != nil {
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return
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}
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Abytes, err := c.Receive()
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if err != nil {
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return
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}
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if bytes.Equal(Abytes, []byte("ping")) {
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room = pingRoom
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c.Send([]byte("pong"))
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return
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}
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err = B.Update(Abytes)
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if err != nil {
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return
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}
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err = c.Send(B.Bytes())
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if err != nil {
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return
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}
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strongKey, err := B.SessionKey()
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if err != nil {
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return
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}
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log.Debugf("strongkey: %x", strongKey)
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// receive salt
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salt, err := c.Receive()
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if err != nil {
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return
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}
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strongKeyForEncryption, _, err := crypt.New(strongKey, salt)
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if err != nil {
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return
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}
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log.Debugf("waiting for password")
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passwordBytesEnc, err := c.Receive()
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if err != nil {
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return
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}
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passwordBytes, err := crypt.Decrypt(passwordBytesEnc, strongKeyForEncryption)
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if err != nil {
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return
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}
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if strings.TrimSpace(string(passwordBytes)) != s.password {
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err = fmt.Errorf("bad password")
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enc, _ := crypt.Decrypt([]byte(err.Error()), strongKeyForEncryption)
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if err := c.Send(enc); err != nil {
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return "", fmt.Errorf("send error: %w", err)
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}
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return
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}
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// send ok to tell client they are connected
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banner := s.banner
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if len(banner) == 0 {
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banner = "ok"
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}
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log.Debugf("sending '%s'", banner)
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bSend, err := crypt.Encrypt([]byte(banner+"|||"+c.Connection().RemoteAddr().String()), strongKeyForEncryption)
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if err != nil {
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return
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}
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err = c.Send(bSend)
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if err != nil {
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return
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}
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// wait for client to tell me which room they want
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log.Debug("waiting for answer")
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enc, err := c.Receive()
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if err != nil {
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return
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}
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roomBytes, err := crypt.Decrypt(enc, strongKeyForEncryption)
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if err != nil {
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return
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}
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room = string(roomBytes)
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s.rooms.Lock()
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// create the room if it is new
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if _, ok := s.rooms.rooms[room]; !ok {
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s.rooms.rooms[room] = roomInfo{
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first: c,
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opened: time.Now(),
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}
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s.rooms.Unlock()
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// tell the client that they got the room
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bSend, err = crypt.Encrypt([]byte("ok"), strongKeyForEncryption)
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if err != nil {
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return
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}
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err = c.Send(bSend)
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if err != nil {
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log.Error(err)
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s.deleteRoom(room)
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return
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}
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log.Debugf("room %s has 1", room)
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return
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}
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if s.rooms.rooms[room].full {
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defer s.deleteRoom(room)
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s.rooms.Unlock()
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bSend, err = crypt.Encrypt([]byte("room full"), strongKeyForEncryption)
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if err != nil {
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return
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}
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err = c.Send(bSend)
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if err != nil {
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log.Error(err)
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return
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}
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return
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}
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log.Debugf("room %s has 2", room)
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s.rooms.rooms[room] = roomInfo{
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first: s.rooms.rooms[room].first,
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second: c,
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opened: s.rooms.rooms[room].opened,
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full: true,
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}
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otherConnection := s.rooms.rooms[room].first
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s.rooms.Unlock()
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// second connection is the sender, time to staple connections
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var wg sync.WaitGroup
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wg.Add(1)
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// start piping
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go func(com1, com2 *comm.Comm, wg *sync.WaitGroup) {
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log.Debug("starting pipes")
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pipe(com1.Connection(), com2.Connection())
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wg.Done()
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log.Debug("done piping")
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}(otherConnection, c, &wg)
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// tell the sender everything is ready
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bSend, err = crypt.Encrypt([]byte("ok"), strongKeyForEncryption)
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if err != nil {
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return
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}
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err = c.Send(bSend)
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if err != nil {
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s.deleteRoom(room)
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return
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}
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wg.Wait()
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// delete room
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s.deleteRoom(room)
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return
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}
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func (s *server) deleteRoom(room string) {
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s.rooms.Lock()
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defer s.rooms.Unlock()
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if _, ok := s.rooms.rooms[room]; !ok {
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return
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}
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log.Debugf("deleting room: %s", room)
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if s.rooms.rooms[room].first != nil {
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s.rooms.rooms[room].first.Close()
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}
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if s.rooms.rooms[room].second != nil {
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s.rooms.rooms[room].second.Close()
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}
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s.rooms.rooms[room] = roomInfo{first: nil, second: nil}
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delete(s.rooms.rooms, room)
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}
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// chanFromConn creates a channel from a Conn object, and sends everything it
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// Read()s from the socket to the channel.
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func chanFromConn(conn net.Conn) chan []byte {
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c := make(chan []byte, 1)
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if err := conn.SetReadDeadline(time.Now().Add(3 * time.Hour)); err != nil {
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log.Warnf("can't set read deadline: %v", err)
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}
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go func() {
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b := make([]byte, models.TCP_BUFFER_SIZE)
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for {
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n, err := conn.Read(b)
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if n > 0 {
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res := make([]byte, n)
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// Copy the buffer so it doesn't get changed while read by the recipient.
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copy(res, b[:n])
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c <- res
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}
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if err != nil {
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log.Debug(err)
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c <- nil
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break
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}
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}
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log.Debug("exiting")
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}()
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return c
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}
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// pipe creates a full-duplex pipe between the two sockets and
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// transfers data from one to the other.
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func pipe(conn1 net.Conn, conn2 net.Conn) {
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chan1 := chanFromConn(conn1)
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chan2 := chanFromConn(conn2)
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for {
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select {
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case b1 := <-chan1:
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if b1 == nil {
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return
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}
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if _, err := conn2.Write(b1); err != nil {
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log.Errorf("write error on channel 1: %v", err)
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}
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case b2 := <-chan2:
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if b2 == nil {
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return
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}
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if _, err := conn1.Write(b2); err != nil {
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log.Errorf("write error on channel 2: %v", err)
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}
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}
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}
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}
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func PingServer(address string) (err error) {
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c, err := comm.NewConnection(address, 200*time.Millisecond)
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if err != nil {
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return
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}
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err = c.Send([]byte("ping"))
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if err != nil {
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return
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}
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b, err := c.Receive()
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if err != nil {
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return
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}
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if bytes.Equal(b, []byte("pong")) {
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return nil
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}
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return fmt.Errorf("no pong")
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}
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// ConnectToTCPServer will initiate a new connection
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// to the specified address, room with optional time limit
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func ConnectToTCPServer(address, password, room string, timelimit ...time.Duration) (c *comm.Comm, banner string, ipaddr string, err error) {
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if len(timelimit) > 0 {
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c, err = comm.NewConnection(address, timelimit[0])
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} else {
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c, err = comm.NewConnection(address)
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}
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if err != nil {
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return
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}
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// get PAKE connection with server to establish strong key to transfer info
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A, err := pake.InitCurve(weakKey, 0, "siec")
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if err != nil {
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return
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}
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err = c.Send(A.Bytes())
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if err != nil {
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return
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}
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Bbytes, err := c.Receive()
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if err != nil {
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return
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}
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err = A.Update(Bbytes)
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if err != nil {
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return
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}
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strongKey, err := A.SessionKey()
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if err != nil {
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return
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}
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log.Debugf("strong key: %x", strongKey)
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strongKeyForEncryption, salt, err := crypt.New(strongKey, nil)
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if err != nil {
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return
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}
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// send salt
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err = c.Send(salt)
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if err != nil {
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return
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}
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log.Debug("sending password")
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bSend, err := crypt.Encrypt([]byte(password), strongKeyForEncryption)
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if err != nil {
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return
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}
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err = c.Send(bSend)
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if err != nil {
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return
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}
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log.Debug("waiting for first ok")
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enc, err := c.Receive()
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if err != nil {
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return
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}
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data, err := crypt.Decrypt(enc, strongKeyForEncryption)
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if err != nil {
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return
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}
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if !strings.Contains(string(data), "|||") {
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err = fmt.Errorf("bad response: %s", string(data))
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return
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}
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banner = strings.Split(string(data), "|||")[0]
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ipaddr = strings.Split(string(data), "|||")[1]
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log.Debug("sending room")
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bSend, err = crypt.Encrypt([]byte(room), strongKeyForEncryption)
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if err != nil {
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return
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}
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err = c.Send(bSend)
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if err != nil {
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return
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}
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log.Debug("waiting for room confirmation")
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enc, err = c.Receive()
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if err != nil {
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return
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}
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data, err = crypt.Decrypt(enc, strongKeyForEncryption)
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if err != nil {
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return
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}
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if !bytes.Equal(data, []byte("ok")) {
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err = fmt.Errorf("got bad response: %s", data)
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return
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}
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log.Debug("all set")
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return
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}
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