Method closeSocket

src/network.js:297–335

* Close the active socket - send FIN to remote, notify main thread

()

     * Close the active socket - send FIN to remote, notify main thread
     */
    closeSocket() {
        // Find the active TCP session (the one that's in FIN_WAIT or ESTABLISHED)
        for (const [key, session] of this.natTable) {
            if (session.state === 'ESTABLISHED' || session.state === 'FIN_WAIT') {
                this.emit('debug', `[TCP] VM closing socket ${key}, state=${session.state}, sending FIN`);
                
                // If we already received FIN from remote (FIN_WAIT), just send ACK
                // Otherwise send FIN to initiate close from our side
                if (session.state === 'FIN_WAIT') {
                    // We already sent FIN-ACK when we received their FIN
                    // Now just clean up - notify main thread to close the socket
                    if (this.netPort) {
                        this.netPort.postMessage({ type: 'tcp-close', key });
                    }
                } else {
                    // ESTABLISHED - we're initiating close, send FIN
                    this.sendTCP(session.srcIP, session.srcPort, session.dstIP, session.dstPort,
                                 session.mySeq, session.myAck, 0x11); // FIN | ACK
                    session.mySeq++;
                    
                    // Notify main thread to close the socket
                    if (this.netPort) {
                        this.netPort.postMessage({ type: 'tcp-close', key });
                    }
                }
                // Delete the session to allow new connections
                this.natTable.delete(key);
                break; // Only close one socket (we only support one connection at a time currently)
            }
        }
        
        // Also clean up any stale closed sessions
        for (const [key, session] of this.natTable) {
            if (session.state === 'CLOSED_BY_REMOTE' || session.state === 'CLOSED' || session.state === 'FIN_SENT') {
                this.emit('debug', `[TCP] Cleaning up stale session ${key}, state=${session.state}`);
                this.natTable.delete(key);
            }
        }
    }
    
    hasPendingData() {
        return this.txBuffer.length > 0;