tls: allow enabling the TLS debug trace

Enable the same trace output that the OpenSSL s_client and s_server
support with their `-trace` option. This is invaluable when debugging
reports of TLS bugs as well as when debugging the internal TLS
implementation.

See:
- https://github.com/nodejs/node/issues/25383
- https://github.com/nodejs/node/issues/17936
- https://github.com/postmanlabs/postman-app-support/issues/5918#issuecomment-465311423

PR-URL: https://github.com/nodejs/node/pull/27376
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: Richard Lau <riclau@uk.ibm.com>

1 files changed, 13 insertions, 0 deletions

diff --git a/lib/_tls_wrap.js b/lib/_tls_wrap.js
index 0b844e6a82..b999c73329 100644
--- a/lib/_tls_wrap.js
+++ b/lib/_tls_wrap.js
@@ -63,6 +63,7 @@ const kErrorEmitted = Symbol('error-emitted');
 const kHandshakeTimeout = Symbol('handshake-timeout');
 const kRes = Symbol('res');
 const kSNICallback = Symbol('snicallback');
+const kEnableTrace = Symbol('enableTrace');
 
 const noop = () => {};
 
@@ -811,6 +812,7 @@ function makeSocketMethodProxy(name) {
   'getSession',
   'getTLSTicket',
   'isSessionReused',
+  'enableTrace',
 ].forEach((method) => {
   TLSSocket.prototype[method] = makeSocketMethodProxy(method);
 });
@@ -872,6 +874,8 @@ function tlsConnectionListener(rawSocket) {
     ALPNProtocols: this.ALPNProtocols,
     SNICallback: this[kSNICallback] || SNICallback
   });
+  if (this[kEnableTrace] && socket._handle)
+    socket._handle.enableTrace();
 
   socket.on('secure', onServerSocketSecure);
 
@@ -992,6 +996,15 @@ function Server(options, listener) {
   if (listener) {
     this.on('secureConnection', listener);
   }
+
+  const enableTrace = options.enableTrace;
+  if (enableTrace === true)
+    this[kEnableTrace] = true;
+  else if (enableTrace === false || enableTrace == null)
+    ;  // Tracing explicitly disabled, or defaulting to disabled.
+  else
+    throw new ERR_INVALID_ARG_TYPE(
+      'options.enableTrace', 'boolean', enableTrace);
 }
 
 Object.setPrototypeOf(Server.prototype, net.Server.prototype);