/** @file
  TCP protocol header file.

  Copyright (c) 2009 - 2017, Intel Corporation. All rights reserved.<BR>

  SPDX-License-Identifier: BSD-2-Clause-Patent

**/

#ifndef _TCP_PROTO_H_
#define _TCP_PROTO_H_

///
/// Tcp states don't change their order. It is used as an
/// index to mTcpOutFlag and other macros.
///
#define TCP_CLOSED       0
#define TCP_LISTEN       1
#define TCP_SYN_SENT     2
#define TCP_SYN_RCVD     3
#define TCP_ESTABLISHED  4
#define TCP_FIN_WAIT_1   5
#define TCP_FIN_WAIT_2   6
#define TCP_CLOSING      7
#define TCP_TIME_WAIT    8
#define TCP_CLOSE_WAIT   9
#define TCP_LAST_ACK     10

///
/// Flags in the TCP header
///
#define TCP_FLG_FIN  0x01
#define TCP_FLG_SYN  0x02
#define TCP_FLG_RST  0x04
#define TCP_FLG_PSH  0x08
#define TCP_FLG_ACK  0x10
#define TCP_FLG_URG  0x20

//
// mask for all the flags
//
#define TCP_FLG_FLAG  0x3F

#define TCP_CONNECT_REFUSED  (-1)     ///< TCP error status
#define TCP_CONNECT_RESET    (-2)     ///< TCP error status
#define TCP_CONNECT_CLOSED   (-3)     ///< TCP error status

//
// Current congestion status as suggested by RFC3782.
//
#define TCP_CONGEST_RECOVER  1      ///< During the NewReno fast recovery.
#define TCP_CONGEST_LOSS     2      ///< Retxmit because of retxmit time out.
#define TCP_CONGEST_OPEN     3      ///< TCP is opening its congestion window.

//
// TCP control flags
//
#define TCP_CTRL_NO_NAGLE      0x0001   ///< Disable Nagle algorithm
#define TCP_CTRL_NO_KEEPALIVE  0x0002   ///< Disable keepalive timer.
#define TCP_CTRL_NO_WS         0x0004   ///< Disable window scale option.
#define TCP_CTRL_RCVD_WS       0x0008   ///< Received a wnd scale option in syn.
#define TCP_CTRL_NO_TS         0x0010   ///< Disable Timestamp option.
#define TCP_CTRL_RCVD_TS       0x0020   ///< Received a Timestamp option in syn.
#define TCP_CTRL_SND_TS        0x0040   ///< Send Timestamp option to remote.
#define TCP_CTRL_SND_URG       0x0080   ///< In urgent send mode.
#define TCP_CTRL_RCVD_URG      0x0100   ///< In urgent receive mode.
#define TCP_CTRL_SND_PSH       0x0200   ///< In PUSH send mode.
#define TCP_CTRL_FIN_SENT      0x0400   ///< FIN is sent.
#define TCP_CTRL_FIN_ACKED     0x0800   ///< FIN is ACKed.
#define TCP_CTRL_TIMER_ON      0x1000   ///< At least one of the timer is on.
#define TCP_CTRL_RTT_ON        0x2000   ///< The RTT measurement is on.
#define TCP_CTRL_ACK_NOW       0x4000   ///< Send the ACK now, don't delay.

//
// Timer related values
//
#define TCP_TIMER_CONNECT    0                      ///< Connection establishment timer.
#define TCP_TIMER_REXMIT     1                      ///< Retransmit timer.
#define TCP_TIMER_PROBE      2                      ///< Window probe timer.
#define TCP_TIMER_KEEPALIVE  3                      ///< Keepalive timer.
#define TCP_TIMER_FINWAIT2   4                      ///< FIN_WAIT_2 timer.
#define TCP_TIMER_2MSL       5                      ///< TIME_WAIT timer.
#define TCP_TIMER_NUMBER     6                      ///< The total number of the TCP timer.
#define TCP_TICK             200                    ///< Every TCP tick is 200ms.
#define TCP_TICK_HZ          5                      ///< The frequence of TCP tick.
#define TCP_RTT_SHIFT        3                      ///< SRTT & RTTVAR scaled by 8.
#define TCP_RTO_MIN          TCP_TICK_HZ            ///< The minimum value of RTO.
#define TCP_RTO_MAX          (TCP_TICK_HZ * 60)     ///< The maximum value of RTO.
#define TCP_FOLD_RTT         4                      ///< Timeout threshold to fold RTT.

//
// Default values for some timers
//
#define TCP_MAX_LOSS            12                           ///< Default max times to retxmit.
#define TCP_KEEPALIVE_IDLE_MIN  (TCP_TICK_HZ * 60 * 60 * 2)  ///< First keepalive.
#define TCP_KEEPALIVE_PERIOD    (TCP_TICK_HZ * 60)
#define TCP_MAX_KEEPALIVE       8
#define TCP_FIN_WAIT2_TIME      (2 * TCP_TICK_HZ)
#define TCP_TIME_WAIT_TIME      (2 * TCP_TICK_HZ)
#define TCP_PAWS_24DAY          (24 * 24 * 60 * 60 * TCP_TICK_HZ)
#define TCP_CONNECT_TIME        (75 * TCP_TICK_HZ)

//
// The header space to be reserved before TCP data to accommodate:
// 60byte IP head + 60byte TCP head + link layer head
//
#define TCP_MAX_HEAD  192

//
// Value ranges for some control option
//
#define TCP_RCV_BUF_SIZE          (2 * 1024 * 1024)
#define TCP_RCV_BUF_SIZE_MIN      (8 * 1024)
#define TCP_SND_BUF_SIZE          (2 * 1024 * 1024)
#define TCP_SND_BUF_SIZE_MIN      (8 * 1024)
#define TCP_BACKLOG               10
#define TCP_BACKLOG_MIN           5
#define TCP_MAX_LOSS_MIN          6
#define TCP_CONNECT_TIME_MIN      (60 * TCP_TICK_HZ)
#define TCP_MAX_KEEPALIVE_MIN     4
#define TCP_KEEPALIVE_IDLE_MAX    (TCP_TICK_HZ * 60 * 60 * 4)
#define TCP_KEEPALIVE_PERIOD_MIN  (TCP_TICK_HZ * 30)
#define TCP_FIN_WAIT2_TIME_MAX    (4 * TCP_TICK_HZ)
#define TCP_TIME_WAIT_TIME_MAX    (60 * TCP_TICK_HZ)

///
/// TCP_CONNECTED: both ends have synchronized their ISN.
///
#define TCP_CONNECTED(state)  ((state) > TCP_SYN_RCVD)

#define TCP_FIN_RCVD(State) \
  ( \
    ((State) == TCP_CLOSE_WAIT) || \
    ((State) == TCP_LAST_ACK) || \
    ((State) == TCP_CLOSING) || \
    ((State) == TCP_TIME_WAIT) \
  )

#define TCP_LOCAL_CLOSED(State) \
  ( \
    ((State) == TCP_FIN_WAIT_1) || \
    ((State) == TCP_FIN_WAIT_2) || \
    ((State) == TCP_CLOSING) || \
    ((State) == TCP_TIME_WAIT) || \
    ((State) == TCP_LAST_ACK) \
  )

//
// Get the TCP_SEG point from a net buffer's ProtoData.
//
#define TCPSEG_NETBUF(NBuf)  ((TCP_SEG *) ((NBuf)->ProtoData))

//
// Macros to compare sequence no
//
#define TCP_SEQ_LT(SeqA, SeqB)   ((INT32) ((SeqA) - (SeqB)) < 0)
#define TCP_SEQ_LEQ(SeqA, SeqB)  ((INT32) ((SeqA) - (SeqB)) <= 0)
#define TCP_SEQ_GT(SeqA, SeqB)   ((INT32) ((SeqB) - (SeqA)) < 0)
#define TCP_SEQ_GEQ(SeqA, SeqB)  ((INT32) ((SeqB) - (SeqA)) <= 0)

//
// TCP_SEQ_BETWEEN return whether b <= m <= e
//
#define TCP_SEQ_BETWEEN(b, m, e)  ((e) - (b) >= (m) - (b))

//
// TCP_SUB_SEQ returns Seq1 - Seq2. Make sure Seq1 >= Seq2
//
#define TCP_SUB_SEQ(Seq1, Seq2)  ((UINT32) ((Seq1) - (Seq2)))

//
// Check whether Flag is on
//
#define TCP_FLG_ON(Value, Flag)  ((BOOLEAN) (((Value) & (Flag)) != 0))
//
// Set and Clear operation on a Flag
//
#define TCP_SET_FLG(Value, Flag)    ((Value) |= (Flag))
#define TCP_CLEAR_FLG(Value, Flag)  ((Value) &= ~(Flag))

//
// Test whether two peers are equal
//
#define TCP_PEER_EQUAL(Pa, Pb, Ver) \
  (((Pa)->Port == (Pb)->Port) && TcpIsIpEqual(&((Pa)->Ip), &((Pb)->Ip), Ver))

//
// Test whether Pa matches Pb, or Pa is more specific
// than pb. Zero means wildcard.
//
#define TCP_PEER_MATCH(Pa, Pb, Ver) \
  ( \
    (((Pb)->Port == 0) || ((Pb)->Port == (Pa)->Port)) && \
    (TcpIsIpZero (&((Pb)->Ip), Ver) || TcpIsIpEqual (&((Pb)->Ip), &((Pa)->Ip), Ver)) \
  )

#define TCP_TIMER_ON(Flag, Timer)     ((Flag) & (1 << (Timer)))
#define TCP_SET_TIMER(Flag, Timer)    ((Flag) = (UINT16) ((Flag) | (1 << (Timer))))
#define TCP_CLEAR_TIMER(Flag, Timer)  ((Flag) = (UINT16) ((Flag) & (~(1 << (Timer)))))

#define TCP_TIME_LT(Ta, Tb)   ((INT32) ((Ta) - (Tb)) < 0)
#define TCP_TIME_LEQ(Ta, Tb)  ((INT32) ((Ta) - (Tb)) <= 0)
#define TCP_SUB_TIME(Ta, Tb)  ((UINT32) ((Ta) - (Tb)))

#define TCP_MAX_WIN  0xFFFFU

///
/// TCP segmentation data.
///
typedef struct _TCP_SEG {
  TCP_SEQNO    Seq;  ///< Starting sequence number.
  TCP_SEQNO    End;  ///< The sequence of the last byte + 1, include SYN/FIN. End-Seq = SEG.LEN.
  TCP_SEQNO    Ack;  ///< ACK field in the segment.
  UINT8        Flag; ///< TCP header flags.
  UINT16       Urg;  ///< Valid if URG flag is set.
  UINT32       Wnd;  ///< TCP window size field.
} TCP_SEG;

///
/// Network endpoint, IP plus Port structure.
///
typedef struct _TCP_PEER {
  EFI_IP_ADDRESS    Ip;   ///< IP address, in network byte order.
  TCP_PORTNO        Port; ///< Port number, in network byte order.
} TCP_PEER;

typedef struct _TCP_CONTROL_BLOCK TCP_CB;

///
/// TCP control block: it includes various states.
///
struct _TCP_CONTROL_BLOCK {
  LIST_ENTRY          List;    ///< Back and forward link entry
  TCP_CB              *Parent; ///< The parent TCP_CB structure

  SOCKET              *Sk;       ///< The socket it controlled.
  TCP_PEER            LocalEnd;  ///< Local endpoint.
  TCP_PEER            RemoteEnd; ///< Remote endpoint.

  LIST_ENTRY          SndQue;   ///< Retxmission queue.
  LIST_ENTRY          RcvQue;   ///< Reassemble queue.
  UINT32              CtrlFlag; ///< Control flags, such as NO_NAGLE.
  INT32               Error;    ///< Soft error status, such as TCP_CONNECT_RESET.

  //
  // RFC793 and RFC1122 defined variables
  //
  UINT8               State;      ///< TCP state, such as SYN_SENT, LISTEN.
  UINT8               DelayedAck; ///< Number of delayed ACKs.
  UINT16              HeadSum;    ///< Checksum of the fixed parts of pesudo
                                  ///< header: Src IP, Dst IP, 0, Protocol,
                                  ///< do not include the TCP length.

  TCP_SEQNO           Iss;       ///< Initial Sending Sequence.
  TCP_SEQNO           SndUna;    ///< First unacknowledged data.
  TCP_SEQNO           SndNxt;    ///< Next data sequence to send.
  TCP_SEQNO           SndPsh;    ///< Send PUSH point.
  TCP_SEQNO           SndUp;     ///< Send urgent point.
  UINT32              SndWnd;    ///< Window advertised by the remote peer.
  UINT32              SndWndMax; ///< Max send window advertised by the peer.
  TCP_SEQNO           SndWl1;    ///< Seq number used for last window update.
  TCP_SEQNO           SndWl2;    ///< Ack no of last window update.
  UINT16              SndMss;    ///< Max send segment size.
  TCP_SEQNO           RcvNxt;    ///< Next sequence no to receive.
  UINT32              RcvWnd;    ///< Window advertised by the local peer.
  TCP_SEQNO           RcvWl2;    ///< The RcvNxt (or ACK) of last window update.
                                 ///< It is necessary because of delayed ACK.

  TCP_SEQNO           RcvUp;                   ///< Urgent point;
  TCP_SEQNO           Irs;                     ///< Initial Receiving Sequence.
  UINT16              RcvMss;                  ///< Max receive segment size.
  UINT16              EnabledTimer;            ///< Which timer is currently enabled.
  UINT32              Timer[TCP_TIMER_NUMBER]; ///< When the timer will expire.
  INT32               NextExpire;              ///< Countdown offset for the nearest timer.
  UINT32              Idle;                    ///< How long the connection is in idle.
  UINT32              ProbeTime;               ///< The time out value for current window prober.
  BOOLEAN             ProbeTimerOn;            ///< If TRUE, the probe time is on.

  //
  // RFC7323 defined variables, about window scale,
  // timestamp and PAWS
  //
  UINT8               SndWndScale; ///< Wndscale received from the peer.
  UINT8               RcvWndScale; ///< Wndscale used to scale local buffer.
  UINT32              TsRecent;    ///< TsRecent to echo to the remote peer.
  UINT32              TsRecentAge; ///< When this TsRecent is updated.

  //
  // RFC2988 defined variables. about RTT measurement
  //
  TCP_SEQNO           RttSeq;     ///< The seq of measured segment now.
  UINT32              RttMeasure; ///< Currently measured RTT in heartbeats.
  UINT32              SRtt;       ///< Smoothed RTT, scaled by 8.
  UINT32              RttVar;     ///< RTT variance, scaled by 8.
  UINT32              Rto;        ///< Current RTO, not scaled.

  //
  // RFC2581, and 3782 variables.
  // Congestion control + NewReno fast recovery.
  //
  UINT32              CWnd;         ///< Sender's congestion window.
  UINT32              Ssthresh;     ///< Slow start threshold.
  TCP_SEQNO           Recover;      ///< Recover point for NewReno.
  UINT16              DupAck;       ///< Number of duplicate ACKs.
  UINT8               CongestState; ///< The current congestion state(RFC3782).
  UINT8               LossTimes;    ///< Number of retxmit timeouts in a row.
  TCP_SEQNO           LossRecover;  ///< Recover point for retxmit.

  //
  // RFC7323
  // Addressing Window Retraction for TCP Window Scale Option.
  //
  TCP_SEQNO           RetxmitSeqMax;     ///< Max Seq number in previous retransmission.

  //
  // configuration parameters, for EFI_TCP4_PROTOCOL specification
  //
  UINT32              KeepAliveIdle;   ///< Idle time before sending first probe.
  UINT32              KeepAlivePeriod; ///< Interval for subsequent keep alive probe.
  UINT8               MaxKeepAlive;    ///< Maximum keep alive probe times.
  UINT8               KeepAliveProbes; ///< The number of keep alive probe.
  UINT16              MaxRexmit;       ///< The maximum number of retxmit before abort.
  UINT32              FinWait2Timeout; ///< The FIN_WAIT_2 timeout.
  UINT32              TimeWaitTimeout; ///< The TIME_WAIT timeout.
  UINT32              ConnectTimeout;  ///< The connect establishment timeout.

  //
  // configuration for tcp provided by user
  //
  BOOLEAN             UseDefaultAddr;
  UINT8               Tos;
  UINT8               Ttl;
  EFI_IPv4_ADDRESS    SubnetMask;

  BOOLEAN             RemoteIpZero; ///< RemoteEnd.Ip is ZERO when configured.
  IP_IO_IP_INFO       *IpInfo;      ///< Pointer reference to Ip used to send pkt
  UINT32              Tick;         ///< 1 tick = 200ms
};

#endif