From 26f4b5e6ba348aebe8af3e555defd897a5084ad3 Mon Sep 17 00:00:00 2001
From: asynts <asynts@gmail.com>
Date: Sun, 20 Sep 2020 12:41:01 +0200
Subject: [PATCH] TelnetServer: Use OutputMemoryStream instead of BufferStream.

I could not test these changes because I could not get my telnet client
(on Linux) to connect to the telnet server running in Serenity.

I tried the follwing:

    # Serenity
    su
    TelnetServer

    # Linux
    telnet localhost 8823

The server then immediatelly closes the connection:

    Connection closed by foreign host.

In the debug logs the following message appears:

    [NetworkTask(5:5)]: handle_tcp: unexpected flags in FinWait2 state
    [NetworkTask(5:5)]: handle_tcp: unexpected flags in Closed state
    [NetworkTask(5:5)]: handle_tcp: unexpected flags in Closed state

This seems to be an unrelated bug in the TCP implementation.
---
 Services/TelnetServer/Client.cpp | 8 +++++---
 Services/TelnetServer/main.cpp   | 1 -
 2 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/Services/TelnetServer/Client.cpp b/Services/TelnetServer/Client.cpp
index e983025df6..dba7c8a052 100644
--- a/Services/TelnetServer/Client.cpp
+++ b/Services/TelnetServer/Client.cpp
@@ -25,8 +25,8 @@
  */
 
 #include "Client.h"
-#include <AK/BufferStream.h>
 #include <AK/ByteBuffer.h>
+#include <AK/MemoryStream.h>
 #include <AK/String.h>
 #include <AK/StringBuilder.h>
 #include <AK/StringView.h>
@@ -171,10 +171,12 @@ void Client::send_command(Command command)
 void Client::send_commands(Vector<Command> commands)
 {
     auto buffer = ByteBuffer::create_uninitialized(commands.size() * 3);
-    BufferStream stream(buffer);
+    OutputMemoryStream stream { buffer };
+
     for (auto& command : commands)
         stream << (u8)IAC << command.command << command.subcommand;
-    stream.snip();
+
+    ASSERT(stream.is_end());
     m_socket->write(buffer.data(), buffer.size());
 }
 
diff --git a/Services/TelnetServer/main.cpp b/Services/TelnetServer/main.cpp
index 6acb900b61..3fd26aff42 100644
--- a/Services/TelnetServer/main.cpp
+++ b/Services/TelnetServer/main.cpp
@@ -25,7 +25,6 @@
  */
 
 #include "Client.h"
-#include <AK/BufferStream.h>
 #include <AK/ByteBuffer.h>
 #include <AK/HashMap.h>
 #include <AK/IPv4Address.h>