You cannot select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
tty-server/session.go

199 lines
5.7 KiB
Go

package main
import (
"container/list"
"crypto/rand"
"encoding/base64"
"encoding/json"
"net"
"sync"
)
type sessionInfo struct {
ID string
URLWebReadWrite string
}
type ttyShareSession struct {
sessionID string
serverURL string
mainRWLock sync.RWMutex
ttySenderConnection *TTYProtocolConn
ttyReceiverConnections *list.List
isAlive bool
lastWindowSizeMsg MsgAll
}
func generateNewSessionID() string {
binID := make([]byte, 32)
_, err := rand.Read(binID)
if err != nil {
panic(err)
}
return base64.URLEncoding.EncodeToString([]byte(binID))
}
func newTTYShareSession(conn net.Conn, serverURL string) *ttyShareSession {
sessionID := generateNewSessionID()
ttyShareSession := &ttyShareSession{
sessionID: sessionID,
serverURL: serverURL,
ttySenderConnection: NewTTYProtocolConn(conn),
ttyReceiverConnections: list.New(),
}
return ttyShareSession
}
func (session *ttyShareSession) InitSender() error {
_, err := session.ttySenderConnection.InitServer(ServerSessionInfo{
URLWebReadWrite: "\n\n **Your tty-share version is deprecated, and will stop working soon. Please update to the latest version!**\n\n" + session.serverURL + "/s/" + session.GetID(),
})
return err
}
func (session *ttyShareSession) GetID() string {
return session.sessionID
}
func copyList(l *list.List) *list.List {
newList := list.New()
for e := l.Front(); e != nil; e = e.Next() {
newList.PushBack(e.Value)
}
return newList
}
func (session *ttyShareSession) handleSenderMessageLock(msg MsgAll) {
switch msg.Type {
case MsgIDWinSize:
// Save the last known size of the window so we pass it to new receivers, and then
// fallthrough. We save the WinSize message as we get it, since we send it anyways
// to the receivers, packed into the same protocol
session.mainRWLock.Lock()
session.lastWindowSizeMsg = msg
session.mainRWLock.Unlock()
fallthrough
case MsgIDWrite:
data, _ := json.Marshal(msg)
session.forEachReceiverLock(func(rcvConn *TTYProtocolConn) bool {
rcvConn.WriteRawData(data)
return true
})
}
}
// Will run on the ttySendeConnection go routine (e.g.: in the TCP connection routine)
func (session *ttyShareSession) HandleSenderConnection() {
session.mainRWLock.Lock()
session.isAlive = true
senderConnection := session.ttySenderConnection
session.mainRWLock.Unlock()
for {
msg, err := senderConnection.ReadMessage()
if err != nil {
log.Debugf("TTYSender connection finished withs with error: %s", err.Error())
break
}
session.handleSenderMessageLock(msg)
}
// Close the connection to all the receivers
log.Debugf("Closing all receiver connection")
session.forEachReceiverLock(func(recvConn *TTYProtocolConn) bool {
log.Debugf("Closing receiver connection")
recvConn.Close()
return true
})
// TODO: clear here the list of receiver
session.mainRWLock.Lock()
session.isAlive = false
session.mainRWLock.Unlock()
}
// Runs the callback cb for each of the receivers in the list of the receivers, as it was when
// this function was called. Note that there might be receivers which might have lost
// the connection since this function was called.
// Return false in the callback to not continue for the rest of the receivers
func (session *ttyShareSession) forEachReceiverLock(cb func(rcvConn *TTYProtocolConn) bool) {
session.mainRWLock.RLock()
// TODO: Maybe find a better way?
rcvsCopy := copyList(session.ttyReceiverConnections)
session.mainRWLock.RUnlock()
for receiverE := rcvsCopy.Front(); receiverE != nil; receiverE = receiverE.Next() {
receiver := receiverE.Value.(*TTYProtocolConn)
if !cb(receiver) {
break
}
}
}
// Will run on the TTYReceiver connection go routine (e.g.: on the websockets connection routine)
// When HandleReceiver will exit, the connection to the TTYReceiver will be closed
func (session *ttyShareSession) HandleReceiver(rawConn *WSConnection) {
rcvProtoConn := NewTTYProtocolConn(rawConn)
session.mainRWLock.Lock()
if !session.isAlive {
log.Warnf("TTYReceiver tried to connect to a session that is not alive anymore. Rejecting it..")
session.mainRWLock.Unlock()
return
}
// Add the receiver to the list of receivers in the seesion, so we need to write-lock
rcvHandleEl := session.ttyReceiverConnections.PushBack(rcvProtoConn)
senderConn := session.ttySenderConnection
lastWindowSize, _ := json.Marshal(session.lastWindowSizeMsg)
session.mainRWLock.Unlock()
log.Debugf("Got new TTYReceiver connection (%s). Serving it..", rawConn.Address())
// Sending the initial size of the window, if we have one
rcvProtoConn.WriteRawData(lastWindowSize)
// Notify the tty-share that we got a new receiver connected
msgRcvConnected, err := MarshalMsg(MsgTTYSenderNewReceiverConnected{
Name: rawConn.Address(),
})
senderConn.WriteRawData(msgRcvConnected)
if err != nil {
log.Errorf("Cannot notify tty sender. Error: %s", err.Error())
}
// Wait until the TTYReceiver will close the connection on its end
for {
msg, err := rcvProtoConn.ReadMessage()
if err != nil {
log.Warnf("Finishing handling the TTYReceiver loop because: %s", err.Error())
break
}
switch msg.Type {
case MsgIDWinSize:
// Ignore these messages from the receiver. For now, the policy is that the sender
// decides on the window size.
case MsgIDWrite:
rawData, _ := json.Marshal(msg)
senderConn.WriteRawData(rawData)
default:
log.Warnf("Receiving unknown data from the receiver")
}
}
log.Debugf("Closing receiver connection")
rcvProtoConn.Close()
// Remove the recevier from the list of the receiver of this session, so we need to write-lock
session.mainRWLock.Lock()
session.ttyReceiverConnections.Remove(rcvHandleEl)
session.mainRWLock.Unlock()
}