/**
* sends data from buffer.
*
* <p>precondition: sendbb is in put mode post condition: sendbb is in put mode
*/
private void sendFromBuffer() {
aa(this, isSender(), "nonsender can't write");
aa(this, isConnected() || isClosurePending(), "needs to be established can't write");
// switch sendbb to get mode
sendbb.flip();
p(this, 3, "Sending from buffer. bb flipped.");
int payloadLength = Math.min(Transport.MAX_PAYLOAD_SIZE, sendbb.limit());
p(this, 4, "Max Payload size: " + Transport.MAX_PAYLOAD_SIZE);
p(this, 4, "payloadlen: " + payloadLength);
dumpState(4);
if (roomForPacket(payloadLength) && payloadLength > 0) {
byte[] payload = new byte[payloadLength];
sendbb.get(payload);
Transport t = makeTransport(Transport.DATA, seqNum, payload);
tcpMan.sendData(this.tsid, t);
p(this, 3, "Write: converting to packet: " + TCPManager.bytesToString(payload));
// only increment the seqNum if a packet is sent
seqNum += payloadLength;
}
// switch back to put mode
sendbb.compact();
dumpState(4);
if (isClosurePending() && sendbb.position() == 0) release();
}
/** Release a connection immediately (abortive shutdown) */
public void release() {
p(this, 3, "Release()");
// TODO(syu) send a FIN
this.state = State.CLOSED;
tcpMan.sendFIN(tsid);
if (isReceiver()) tcpMan.remove(tsid);
}
/**
* Accept a connection on a socket
*
* <p>Needs to trigger sending an ACK
*
* @return TCPSock The first established connection on the request queue remove from welcomeQueue
* adds recvSocket to socketSpace sends Ack
*/
public TCPSock accept() {
aa(this, this.sockType == SocketType.WELCOME, "accept() called by non-welcome socket");
aa(this, this.state == State.LISTEN, "accept() called when not listening");
if (welcomeQueue.isEmpty()) return null;
p(this, 3, "accept()");
TCPSock recvSock = welcomeQueue.remove(0);
recvSock.state = State.ESTABLISHED;
p(recvSock, 4, "established");
tcpMan.add(recvSock.tsid, recvSock);
tcpMan.sendACK(recvSock.tsid);
return recvSock;
}
/**
* Initiate connection to a remote socket
*
* @param destAddr int Destination node address
* @param destPort int Destination port
* @return int 0 on success, -1 otherwise
*/
public int connect(int destAddr, int destPort) {
// if not starting from a closed state, connect should fail.
if (!isClosed() || !isSender()) {
pe(this, " connect() called on inappropriated");
return -1;
}
p(this, 3, "Connect() to: " + destAddr + ":" + destPort);
this.tsid.remoteAddr = destAddr;
this.tsid.remotePort = destPort;
tcpMan.add(this.tsid, this);
tcpMan.sendSYN(this.tsid);
this.state = State.SYN_SENT;
return 0;
}
/**
* Listen for connections on a socket
*
* @param backlog int Maximum number of pending connections
* @return int 0 on success, -1 otherwise
*/
public int listen(int backlog) {
if (sockType != SocketType.WELCOME) {
die(this, "not a welcome socket");
return -1;
}
this.state = State.LISTEN;
p(this, 3, "listening. backlog: " + backlog);
this.backlog = backlog;
welcomeQueue = new ArrayList<TCPSock>(backlog);
tcpMan.addWelcomeSocket(this);
return 0;
}
public void dataReceived(Transport t) {
aa(this, isReceiver(), "DATA received by non receiver socket");
aa(this, isConnected(), "DATA received by invalid socket state");
int inSeqNum = t.getSeqNum();
p(this, 3, "dataReceived() seqnum: " + inSeqNum);
transportBuffer.put(inSeqNum, t);
deliverToBuffer();
dumpState(4);
p(this, 3, "ending dataReceived");
tcpMan.sendACK(this.tsid);
}
public TCPSock(TCPManager tcpMan, SocketType type) {
this.tcpMan = tcpMan;
this.tsid = new TCPSockID();
this.tsid.localAddr = tcpMan.getAddr();
this.state = State.CLOSED;
this.sockType = type;
switch (sockType) {
case SENDER:
initSender();
break;
case RECEIVER:
initReceiver();
break;
case WELCOME:
initWelcome();
break;
}
this.seqNum = 0;
}