Updating ssh protocol to support disconnect message and language in packet

lib/client.js

@@ -1176,9 +1176,10 @@ class Client extends EventEmitter {
     return this;
   }
 
-  end() {
+  end(reason = null, message = '', lang = '') {
+    reason = reason || DISCONNECT_REASON.BY_APPLICATION;
     if (this._sock && isWritable(this._sock)) {
-      this._protocol.disconnect(DISCONNECT_REASON.BY_APPLICATION);
+      this._protocol.disconnect(reason, message, lang);
       this._sock.end();
     }
     return this;

lib/protocol/Protocol.js

@@ -321,23 +321,37 @@ class Protocol {
 
   // Global
   // ------
-  disconnect(reason) {
-    const pktLen = 1 + 4 + 4 + 4;
+  disconnect(reason, message = '', lang = '') {
+    const msgLen = Buffer.byteLength(message);
+    const langLen = Buffer.byteLength(lang);
+    const pktLen = 1 + 4 + 4 + msgLen + 4 + langLen;
     // We don't use _packetRW.write.* here because we need to make sure that
     // we always get a full packet allocated because this message can be sent
     // at any time -- even during a key exchange
     let p = this._packetRW.write.allocStartKEX;
     const packet = this._packetRW.write.alloc(pktLen, true);
-    const end = p + pktLen;
 
     if (!VALID_DISCONNECT_REASONS.has(reason))
       reason = DISCONNECT_REASON.PROTOCOL_ERROR;
 
     packet[p] = MESSAGE.DISCONNECT;
     writeUInt32BE(packet, reason, ++p);
-    packet.fill(0, p += 4, end);
 
-    this._debug && this._debug(`Outbound: Sending DISCONNECT (${reason})`);
+    writeUInt32BE(packet, msgLen, p += 4);
+    if (msgLen > 0){
+      packet.utf8Write(message, p += 4, msgLen);
+    } else {
+      // This is because the SSH protocol expects a 4-byte length field for the message,
+      // followed by the message data (which may be zero bytes).
+      // Advancing the pointer by 4 ensures the next field (the language tag)
+      // is written at the correct offset, maintaining the correct packet structure.
+      p += 4;
+    }
+
+    writeUInt32BE(packet, langLen, p += msgLen);
+    if (langLen > 0) packet.utf8Write(lang, p += 4, langLen);
+
+    this._debug && this._debug(`Outbound: Sending DISCONNECT (${reason}, message: ${message})`);
     sendPacket(this, this._packetRW.write.finalize(packet, true), true);
   }
   ping() {

lib/server.js

@@ -1278,9 +1278,10 @@ class Client extends EventEmitter {
     }
   }
 
-  end() {
+  end(reason = null, message = '', lang = '') {
+    reason = reason || DISCONNECT_REASON.BY_APPLICATION;
     if (this._sock && isWritable(this._sock)) {
-      this._protocol.disconnect(DISCONNECT_REASON.BY_APPLICATION);
+      this._protocol.disconnect(reason, message, lang);
       this._sock.end();
     }
     return this;