/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */

/*

 * Copyright (c) 2007 Georgia Tech Research Corporation

 * Copyright (c) 2010 Adrian Sai-wah Tam

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation;

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 *

 * Author: Adrian Sai-wah Tam <adrian.sw.tam@gmail.com>

 */

#ifndef TCP_SOCKET_BASE_H

#define TCP_SOCKET_BASE_H

#include <stdint.h>

#include <queue>

#include "ns3/callback.h"

#include "ns3/traced-value.h"

#include "ns3/tcp-socket.h"

#include "ns3/ptr.h"

#include "ns3/ipv4-address.h"

#include "ns3/ipv4-header.h"

#include "ns3/ipv4-interface.h"

#include "ns3/ipv6-header.h"

#include "ns3/ipv6-interface.h"

#include "ns3/event-id.h"

#include "tcp-tx-buffer.h"

#include "tcp-rx-buffer.h"

#include "rtt-estimator.h"

namespace ns3 {

class Ipv4EndPoint;

class Ipv6EndPoint;

class Node;

class Packet;

class TcpL4Protocol;

class TcpHeader;

/**

 * \ingroup socket

 * \ingroup tcp

 *

 * \brief A base class for implementation of a stream socket using TCP.

 *

 * This class contains the essential components of TCP, as well as a sockets

 * interface for upper layers to call. This serves as a base for other TCP

 * functions where the sliding window mechanism is handled here. This class

 * provides connection orientation and sliding window flow control. Part of

 * this class is modified from the original NS-3 TCP socket implementation

 * (TcpSocketImpl) by Raj Bhattacharjea <raj.b@gatech.edu> of Georgia Tech.

 */

class TcpSocketBase : public TcpSocket

{

public:

  /**

   * Get the type ID.

   * \brief Get the type ID.

   * \return the object TypeId

   */

  static TypeId GetTypeId (void);

  /**

   * Create an unbound TCP socket

   */

  TcpSocketBase (void);

  /**

   * Clone a TCP socket, for use upon receiving a connection request in LISTEN state

   *

   * \param sock the original Tcp Socket

   */

  TcpSocketBase (const TcpSocketBase& sock);

  virtual ~TcpSocketBase (void);

  // Set associated Node, TcpL4Protocol, RttEstimator to this socket

  /**

   * \brief Set the associated node.

   * \param node the node

   */

  virtual void SetNode (Ptr<Node> node);

  /**

   * \brief Set the associated TCP L4 protocol.

   * \param tcp the TCP L4 protocol

   */

  virtual void SetTcp (Ptr<TcpL4Protocol> tcp);

  /**

   * \brief Set the associated RTT estimator.

   * \param rtt the RTT estimator

   */

  virtual void SetRtt (Ptr<RttEstimator> rtt);

  // Necessary implementations of null functions from ns3::Socket

  virtual enum SocketErrno GetErrno (void) const;    // returns m_errno

  virtual enum SocketType GetSocketType (void) const; // returns socket type

  virtual Ptr<Node> GetNode (void) const;            // returns m_node

  virtual int Bind (void);    // Bind a socket by setting up endpoint in TcpL4Protocol

  virtual int Bind6 (void);    // Bind a socket by setting up endpoint in TcpL4Protocol

  virtual int Bind (const Address &address);         // ... endpoint of specific addr or port

  virtual int Connect (const Address &address);      // Setup endpoint and call ProcessAction() to connect

  virtual int Listen (void);  // Verify the socket is in a correct state and call ProcessAction() to listen

  virtual int Close (void);   // Close by app: Kill socket upon tx buffer emptied

  virtual int ShutdownSend (void);    // Assert the m_shutdownSend flag to prevent send to network

  virtual int ShutdownRecv (void);    // Assert the m_shutdownRecv flag to prevent forward to app

  virtual int Send (Ptr<Packet> p, uint32_t flags);  // Call by app to send data to network

  virtual int SendTo (Ptr<Packet> p, uint32_t flags, const Address &toAddress); // Same as Send(), toAddress is insignificant

  virtual Ptr<Packet> Recv (uint32_t maxSize, uint32_t flags); // Return a packet to be forwarded to app

  virtual Ptr<Packet> RecvFrom (uint32_t maxSize, uint32_t flags, Address &fromAddress); // ... and write the remote address at fromAddress

  virtual uint32_t GetTxAvailable (void) const; // Available Tx buffer size

  virtual uint32_t GetRxAvailable (void) const; // Available-to-read data size, i.e. value of m_rxAvailable

  virtual int GetSockName (Address &address) const; // Return local addr:port in address

  virtual void BindToNetDevice (Ptr<NetDevice> netdevice); // NetDevice with my m_endPoint

protected:

  // Implementing ns3::TcpSocket -- Attribute get/set

  // inherited, no need to doc

  virtual void     SetSndBufSize (uint32_t size);

  virtual uint32_t GetSndBufSize (void) const;

  virtual void     SetRcvBufSize (uint32_t size);

  virtual uint32_t GetRcvBufSize (void) const;

  virtual void     SetSegSize (uint32_t size);

  virtual uint32_t GetSegSize (void) const;

  virtual void     SetInitialCwnd (uint32_t cwnd) = 0;

  virtual uint32_t GetInitialCwnd (void) const = 0;

  virtual void     SetConnTimeout (Time timeout);

  virtual Time     GetConnTimeout (void) const;

  virtual void     SetConnCount (uint32_t count);

  virtual uint32_t GetConnCount (void) const;

  virtual void     SetDelAckTimeout (Time timeout);

  virtual Time     GetDelAckTimeout (void) const;

  virtual void     SetDelAckMaxCount (uint32_t count);

  virtual uint32_t GetDelAckMaxCount (void) const;

  virtual void     SetTcpNoDelay (bool noDelay);

  virtual bool     GetTcpNoDelay (void) const;

  virtual void     SetPersistTimeout (Time timeout);

  virtual Time     GetPersistTimeout (void) const;

  virtual bool     SetAllowBroadcast (bool allowBroadcast);

  virtual bool     GetAllowBroadcast (void) const;

  // Helper functions: Connection set up

  /**

   * \brief Common part of the two Bind(), i.e. set callback and remembering local addr:port

   *

   * \returns 0 on success, -1 on failure

   */

  int SetupCallback (void);

  /**

   * \brief Perform the real connection tasks: Send SYN if allowed, RST if invalid

   *

   * \returns 0 on success

   */

  int DoConnect (void);

  /**

   * \brief Schedule-friendly wrapper for Socket::NotifyConnectionSucceeded()

   */

  void ConnectionSucceeded (void);

  /**

   * \brief Configure the endpoint to a local address. Called by Connect() if Bind() didn't specify one.

   *

   * \returns 0 on success

   */

  int SetupEndpoint (void);

  /**

   * \brief Configure the endpoint v6 to a local address. Called by Connect() if Bind() didn't specify one.

   *

   * \returns 0 on success

   */

  int SetupEndpoint6 (void);

  /**

   * \brief Complete a connection by forking the socket

   *

   * This function is called only if a SYN received in LISTEN state. After

   * TcpSocketBase cloned, allocate a new end point to handle the incoming

   * connection and send a SYN+ACK to complete the handshake.

   *

   * \param p the packet triggering the fork

   * \param tcpHeader the TCP header of the triggering packet

   * \param fromAddress the address of the remote host

   * \param toAddress the address the connection is directed to

   */

  void CompleteFork (Ptr<Packet> p, const TcpHeader& tcpHeader, const Address& fromAddress, const Address& toAddress);

  // Helper functions: Transfer operation

  /**

   * \brief Called by the L3 protocol when it received a packet to pass on to TCP.

   *

   * \param packet the incoming packet

   * \param header the packet's IPv4 header

   * \param port the remote port

   * \param incomingInterface the incoming interface

   */

  void ForwardUp (Ptr<Packet> packet, Ipv4Header header, uint16_t port, Ptr<Ipv4Interface> incomingInterface);

  /**

   * \brief Called by the L3 protocol when it received a packet to pass on to TCP.

   *

   * \param packet the incoming packet

   * \param header the packet's IPv6 header

   * \param port the remote port

   * \param incomingInterface the incoming interface

   */

  void ForwardUp6 (Ptr<Packet> packet, Ipv6Header header, uint16_t port, Ptr<Ipv6Interface> incomingInterface);

  /**

   * \brief Called by TcpSocketBase::ForwardUp().

   *

   * \param packet the incoming packet

   * \param header the packet's IPv4 header

   * \param port the remote port

   * \param incomingInterface the incoming interface

   */

  virtual void DoForwardUp (Ptr<Packet> packet, Ipv4Header header, uint16_t port, Ptr<Ipv4Interface> incomingInterface); //Get a pkt from L3

  /**

   * \brief Called by TcpSocketBase::ForwardUp6().

   *

   * \param packet the incoming packet

   * \param header the packet's IPv6 header

   * \param port the remote port

   */

  virtual void DoForwardUp (Ptr<Packet> packet, Ipv6Header header, uint16_t port);

  /**

   * \brief Called by the L3 protocol when it received an ICMP packet to pass on to TCP.

   *

   * \param icmpSource the ICMP source address

   * \param icmpTtl the ICMP Time to Live

   * \param icmpType the ICMP Type

   * \param icmpCode the ICMP Code

   * \param icmpInfo the ICMP Info

   */

  void ForwardIcmp (Ipv4Address icmpSource, uint8_t icmpTtl, uint8_t icmpType, uint8_t icmpCode, uint32_t icmpInfo);

  /**

   * \brief Called by the L3 protocol when it received an ICMPv6 packet to pass on to TCP.

   *

   * \param icmpSource the ICMP source address

   * \param icmpTtl the ICMP Time to Live

   * \param icmpType the ICMP Type

   * \param icmpCode the ICMP Code

   * \param icmpInfo the ICMP Info

   */

  void ForwardIcmp6 (Ipv6Address icmpSource, uint8_t icmpTtl, uint8_t icmpType, uint8_t icmpCode, uint32_t icmpInfo);

  /**

   * \brief Send as much pending data as possible according to the Tx window.

   *

   * Note that this function did not implement the PSH flag.

   *

   * \param withAck forces an ACK to be sent

   * \returns true if some data have been sent

   */

  bool SendPendingData (bool withAck = false);

  /**

   * \brief Extract at most maxSize bytes from the TxBuffer at sequence seq, add the

   *        TCP header, and send to TcpL4Protocol

   *

   * \param seq the sequence number

   * \param maxSize the maximum data block to be transmitted (in bytes)

   * \param withAck forces an ACK to be sent

   * \returns the number of bytes sent

   */

  uint32_t SendDataPacket (SequenceNumber32 seq, uint32_t maxSize, bool withAck);

  /**

   * \brief Send a empty packet that carries a flag, e.g. ACK

   *

   * \param flags the packet's flags

   */

  void SendEmptyPacket (uint8_t flags);

  /**

   * \brief Send reset and tear down this socket

   */

  void SendRST (void);

  /**

   * \brief Check if a sequence number range is within the rx window

   *

   * \param head start of the Sequence window

   * \param tail end of the Sequence window

   * \returns true if it is in range

   */

  bool OutOfRange (SequenceNumber32 head, SequenceNumber32 tail) const;

  // Helper functions: Connection close

  /**

   * \brief Close a socket by sending RST, FIN, or FIN+ACK, depend on the current state

   *

   * \returns 0 on success

   */

  int DoClose (void);

  /**

   * \brief Peacefully close the socket by notifying the upper layer and deallocate end point

   */

  void CloseAndNotify (void);

  /**

   * \brief Kill this socket by zeroing its attributes (IPv4)

   *

   * This is a callback function configured to m_endpoint in

   * SetupCallback(), invoked when the endpoint is destroyed.

   */

  void Destroy (void);

  /**

   * \brief Kill this socket by zeroing its attributes (IPv6)

   *

   * This is a callback function configured to m_endpoint in

   * SetupCallback(), invoked when the endpoint is destroyed.

   */

  void Destroy6 (void);

  /**

   * \brief Deallocate m_endPoint and m_endPoint6

   */

  void DeallocateEndPoint (void);

  /**

   * \brief Received a FIN from peer, notify rx buffer

   *

   * \param p the packet

   * \param tcpHeader the packet's TCP header

   */

  void PeerClose (Ptr<Packet> p, const TcpHeader& tcpHeader);

  /**

   * \brief FIN is in sequence, notify app and respond with a FIN

   */

  void DoPeerClose (void);

  /**

   * \brief Cancel all timer when endpoint is deleted

   */

  void CancelAllTimers (void);

  /**

   * \brief Move from CLOSING or FIN_WAIT_2 to TIME_WAIT state

   */

  void TimeWait (void);

  // State transition functions

  /**

   * \brief Received a packet upon ESTABLISHED state.

   *

   * This function is mimicking the role of tcp_rcv_established() in tcp_input.c in Linux kernel.

   *

   * \param packet the packet

   * \param tcpHeader the packet's TCP header

   */

  void ProcessEstablished (Ptr<Packet> packet, const TcpHeader& tcpHeader); // Received a packet upon ESTABLISHED state

  /**

   * \brief Received a packet upon LISTEN state.

   *

   * \param packet the packet

   * \param tcpHeader the packet's TCP header

   * \param fromAddress the source address

   * \param toAddress the destination address

   */

  void ProcessListen (Ptr<Packet> packet, const TcpHeader& tcpHeader,

                      const Address& fromAddress, const Address& toAddress);

  /**

   * \brief Received a packet upon SYN_SENT

   *

   * \param packet the packet

   * \param tcpHeader the packet's TCP header

   */

  void ProcessSynSent (Ptr<Packet> packet, const TcpHeader& tcpHeader);

  /**

   * \brief Received a packet upon SYN_RCVD.

   *

   * \param packet the packet

   * \param tcpHeader the packet's TCP header

   * \param fromAddress the source address

   * \param toAddress the destination address

   */

  void ProcessSynRcvd (Ptr<Packet> packet, const TcpHeader& tcpHeader,

                       const Address& fromAddress, const Address& toAddress);

  /**

   * \brief Received a packet upon CLOSE_WAIT, FIN_WAIT_1, FIN_WAIT_2

   *

   * \param packet the packet

   * \param tcpHeader the packet's TCP header

   */

  void ProcessWait (Ptr<Packet> packet, const TcpHeader& tcpHeader);

  /**

   * \brief Received a packet upon CLOSING

   *

   * \param packet the packet

   * \param tcpHeader the packet's TCP header

   */

  void ProcessClosing (Ptr<Packet> packet, const TcpHeader& tcpHeader);

  /**

   * \brief Received a packet upon LAST_ACK

   *

   * \param packet the packet

   * \param tcpHeader the packet's TCP header

   */

  void ProcessLastAck (Ptr<Packet> packet, const TcpHeader& tcpHeader);

  // Window management

  /**

   * \brief Return count of number of unacked bytes

   * \returns count of number of unacked bytes

   */

  virtual uint32_t UnAckDataCount (void);

  /**

   * \brief Return total bytes in flight

   * \returns total bytes in flight

   */

  virtual uint32_t BytesInFlight (void);

  /**

   * \brief Return the max possible number of unacked bytes

   * \returns the max possible number of unacked bytes

   */

  virtual uint32_t Window (void);

  /**

   * \brief Return unfilled portion of window

   * \return unfilled portion of window

   */

  virtual uint32_t AvailableWindow (void);

  /**

   * \brief The amount of Rx window announced to the peer

   * \returns size of Rx window announced to the peer

   */

  virtual uint16_t AdvertisedWindowSize (void);

  // Manage data tx/rx

  /**

   * \brief Call CopyObject<> to clone me

   * \returns a copy of the socket

   */

  virtual Ptr<TcpSocketBase> Fork (void) = 0;

  /**

   * \brief Received an ACK packet

   * \param packet the packet

   * \param tcpHeader the packet's TCP header

   */

  virtual void ReceivedAck (Ptr<Packet> packet, const TcpHeader& tcpHeader);

  /**

   * \brief Recv of a data, put into buffer, call L7 to get it if necessary

   * \param packet the packet

   * \param tcpHeader the packet's TCP header

   */

  virtual void ReceivedData (Ptr<Packet> packet, const TcpHeader& tcpHeader);

  /**

   * \brief Take into account the packet for RTT estimation

   * \param tcpHeader the packet's TCP header

   */

  virtual void EstimateRtt (const TcpHeader& tcpHeader);

  /**

   * \brief Update buffers w.r.t. ACK