fix(tls): Improve TLS alert handling in connection handler: use the new TlsAlert class to send proper unrecognized_name alerts when a ClientHello is missing SNI and wait for a retry on the same connection before closing. Also, add alertFallbackTimeout tracking to connection records for better timeout management.
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@ -11,6 +11,7 @@ import { TlsManager } from './classes.pp.tlsmanager.js';
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import { NetworkProxyBridge } from './classes.pp.networkproxybridge.js';
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import { TimeoutManager } from './classes.pp.timeoutmanager.js';
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import { PortRangeManager } from './classes.pp.portrangemanager.js';
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import { TlsAlert } from './classes.pp.tlsalert.js';
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/**
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* Handles new connection processing and setup logic
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@ -560,95 +561,125 @@ export class ConnectionHandler {
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// Block ClientHello without SNI when allowSessionTicket is false
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console.log(
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`[${connectionId}] No SNI detected in ClientHello and allowSessionTicket=false. ` +
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`Sending warning unrecognized_name alert to encourage immediate retry with SNI.`
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`Sending unrecognized_name alert to encourage immediate retry with SNI on same connection.`
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);
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// Set the termination reason first
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if (record.incomingTerminationReason === null) {
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record.incomingTerminationReason = 'session_ticket_blocked_no_sni';
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this.connectionManager.incrementTerminationStat(
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'incoming',
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'session_ticket_blocked_no_sni'
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);
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}
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// Create a warning-level alert for unrecognized_name
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// This encourages Chrome to retry immediately with SNI
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const serverNameUnknownAlertData = Buffer.from([
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0x15, // Alert record type
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0x03,
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0x03, // TLS 1.2 version
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0x00,
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0x02, // Length
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0x01, // Warning alert level (not fatal)
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0x70, // unrecognized_name alert (code 112)
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]);
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// Send a handshake_failure alert instead of unrecognized_name
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const sslHandshakeFailureAlertData = Buffer.from([
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0x15, // Alert record type
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0x03,
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0x03, // TLS 1.2 version
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0x00,
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0x02, // Length
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0x01, // Warning alert level (not fatal)
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0x28, // handshake_failure alert (40) instead of unrecognized_name (112)
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]);
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const closeNotifyAlert = Buffer.from([
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0x15, // Alert record type
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0x03,
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0x03, // TLS 1.2 version
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0x00,
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0x02, // Length
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0x01, // Warning alert level (1)
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0x00, // close_notify alert (0)
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]);
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const certificateExpiredAlert = Buffer.from([
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0x15, // Alert record type
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0x03,
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0x03, // TLS 1.2 version
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0x00,
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0x02, // Length
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0x01, // Warning alert level (1)
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0x2F, // certificate_expired alert (47)
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]);
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try {
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// Use cork/uncork to ensure the alert is sent as a single packet
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// Send the alert but do NOT end the connection
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// Using our new TlsAlert class for better alert management
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socket.cork();
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const writeSuccessful = socket.write(serverNameUnknownAlertData);
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socket.write(TlsAlert.alerts.unrecognizedName);
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socket.uncork();
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// Function to handle the clean socket termination - but more gradually
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const finishConnection = () => {
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// Give Chrome more time to process the alert before closing
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// We won't call destroy() at all - just end() and let the socket close naturally
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// Log the cleanup but wait for natural closure
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setTimeout(() => {
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socket.end();
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this.connectionManager.cleanupConnection(record, 'session_ticket_blocked_no_sni');
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}, 5000); // Longer delay to let socket cleanup happen naturally
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};
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if (writeSuccessful) {
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// Wait longer before ending connection to ensure alert is processed by client
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setTimeout(finishConnection, 200); // Increased from 50ms to 200ms
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} else {
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// If the kernel buffer was full, wait for the drain event
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socket.once('drain', () => {
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// Wait longer after drain as well
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setTimeout(finishConnection, 200);
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});
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// Safety timeout is increased too
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setTimeout(() => {
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socket.removeAllListeners('drain');
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finishConnection();
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}, 400); // Increased from 250ms to 400ms
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console.log(
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`[${connectionId}] Alert sent, waiting for new ClientHello on same connection...`
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);
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// Remove existing data listener and wait for a new ClientHello
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socket.removeAllListeners('data');
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// Set up a new data handler to capture the next message
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socket.once('data', (retryChunk) => {
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// Cancel the fallback timeout as we received data
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if (record.alertFallbackTimeout) {
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clearTimeout(record.alertFallbackTimeout);
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record.alertFallbackTimeout = null;
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}
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// Check if this is a new ClientHello
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if (this.tlsManager.isClientHello(retryChunk)) {
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console.log(`[${connectionId}] Received new ClientHello after alert`);
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// Extract SNI from the new ClientHello
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const newServerName = this.tlsManager.extractSNI(retryChunk, connInfo) || '';
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if (newServerName) {
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console.log(`[${connectionId}] New ClientHello contains SNI: ${newServerName}`);
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// Update the record with the new SNI
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record.lockedDomain = newServerName;
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// Continue with normal connection setup using the new chunk with SNI
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setupConnection(newServerName, retryChunk);
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} else {
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console.log(
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`[${connectionId}] New ClientHello still missing SNI, closing connection`
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);
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// If still no SNI after retry, now we can close the connection
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if (record.incomingTerminationReason === null) {
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record.incomingTerminationReason = 'session_ticket_blocked_no_sni';
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this.connectionManager.incrementTerminationStat(
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'incoming',
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'session_ticket_blocked_no_sni'
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);
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}
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// Send a close_notify alert before ending the connection
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TlsAlert.sendCloseNotify(socket)
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.catch((err) => {
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console.log(`[${connectionId}] Error sending close_notify: ${err.message}`);
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})
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.finally(() => {
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// Clean up even if sending the alert fails
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this.connectionManager.cleanupConnection(
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record,
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'session_ticket_blocked_no_sni'
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);
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});
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}
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} else {
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console.log(
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`[${connectionId}] Received non-ClientHello data after alert, closing connection`
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);
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// If we got something other than a ClientHello, close the connection
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if (record.incomingTerminationReason === null) {
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record.incomingTerminationReason = 'invalid_protocol';
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this.connectionManager.incrementTerminationStat('incoming', 'invalid_protocol');
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}
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// Send a protocol_version alert before ending the connection
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TlsAlert.send(socket, TlsAlert.LEVEL_FATAL, TlsAlert.PROTOCOL_VERSION, true)
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.catch((err) => {
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console.log(
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`[${connectionId}] Error sending protocol_version alert: ${err.message}`
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);
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})
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.finally(() => {
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// Clean up even if sending the alert fails
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this.connectionManager.cleanupConnection(record, 'invalid_protocol');
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});
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}
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});
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// Set a fallback timeout in case the client doesn't respond
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const fallbackTimeout = setTimeout(() => {
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console.log(`[${connectionId}] No response after alert, closing connection`);
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if (record.incomingTerminationReason === null) {
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record.incomingTerminationReason = 'alert_timeout';
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this.connectionManager.incrementTerminationStat('incoming', 'alert_timeout');
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}
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// Send a close_notify alert before ending the connection
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TlsAlert.sendCloseNotify(socket)
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.catch((err) => {
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console.log(`[${connectionId}] Error sending close_notify: ${err.message}`);
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})
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.finally(() => {
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// Clean up even if sending the alert fails
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this.connectionManager.cleanupConnection(record, 'alert_timeout');
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});
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}, 10000); // 10 second timeout
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// Make sure the timeout doesn't keep the process alive
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if (fallbackTimeout.unref) {
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fallbackTimeout.unref();
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}
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// Store the timeout in the record so it can be cleared during cleanup
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record.alertFallbackTimeout = fallbackTimeout;
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} catch (err) {
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// If we can't send the alert, fall back to immediate termination
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console.log(`[${connectionId}] Error sending TLS alert: ${err.message}`);
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@ -656,6 +687,7 @@ export class ConnectionHandler {
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this.connectionManager.cleanupConnection(record, 'session_ticket_blocked_no_sni');
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}
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// Return early to prevent the normal flow
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return;
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}
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}
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