text: #pragma once
  
  #include <Kernel/Net/IPv4Socket.h>
  
  class TCPSocket final : public IPv4Socket {
  public:
      static Retained<TCPSocket> create(int protocol);
      virtual ~TCPSocket() override;
  
      enum class State
      {
          Disconnected,
          Connecting,
          Connected,
          Disconnecting,
      };
  
      State state() const { return m_state; }
      void set_state(State state) { m_state = state; }
  
      void set_ack_number(dword n) { m_ack_number = n; }
      void set_sequence_number(dword n) { m_sequence_number = n; }
      dword ack_number() const { return m_ack_number; }
      dword sequence_number() const { return m_sequence_number; }
  
      void send_tcp_packet(word flags, const void* = nullptr, int = 0);
  
      static Lockable<HashMap<word, TCPSocket*>>& sockets_by_port();
      static TCPSocketHandle from_port(word);
  
  private:
      explicit TCPSocket(int protocol);
      virtual const char* class_name() const override { return "TCPSocket"; }
  
      static NetworkOrdered<word> compute_tcp_checksum(const IPv4Address& source, const IPv4Address& destination, const TCPPacket&, word payload_size);
  
      virtual int protocol_receive(const ByteBuffer&, void* buffer, size_t buffer_size, int flags, sockaddr* addr, socklen_t* addr_length) override;
      virtual int protocol_send(const void*, int) override;
      virtual KResult protocol_connect(FileDescriptor&, ShouldBlock) override;
      virtual int protocol_allocate_local_port() override;
      virtual bool protocol_is_disconnected() const override;
      virtual KResult protocol_bind() override;
  
      dword m_sequence_number { 0 };
      dword m_ack_number { 0 };
      State m_state { State::Disconnected };
  };
  
  class TCPSocketHandle : public SocketHandle {
  public:
      TCPSocketHandle() {}
  
      TCPSocketHandle(RetainPtr<TCPSocket>&& socket)
          : SocketHandle(move(socket))
      {
      }
  
      TCPSocketHandle(TCPSocketHandle&& other)
          : SocketHandle(move(other))
      {
      }
  
      TCPSocketHandle(const TCPSocketHandle&) = delete;
      TCPSocketHandle& operator=(const TCPSocketHandle&) = delete;
  
      TCPSocket* operator->() { return &socket(); }
      const TCPSocket* operator->() const { return &socket(); }
  
      TCPSocket& socket() { return static_cast<TCPSocket&>(SocketHandle::socket()); }
      const TCPSocket& socket() const { return static_cast<const TCPSocket&>(SocketHandle::socket()); }
  };
  