tcp.h

用于嵌入式系统的TCP/IP协议栈及若干服务

/*
*            Copyright (c) 1998-2001 by NETsilicon Inc.
*
*  This software is copyrighted by and is the sole property of
*  NETsilicon.  All rights, title, ownership, or other interests
*  in the software remain the property of NETsilicon.  This
*  software may only be used in accordance with the corresponding
*  license agreement.  Any unauthorized use, duplication, transmission,
*  distribution, or disclosure of this software is expressly forbidden.
*
*  This Copyright notice may not be removed or modified without prior
*  written consent of NETsilicon.
*
*  NETsilicon, reserves the right to modify this software
*  without notice.
*
*  NETsilicon
*  411 Waverley Oaks Road                  USA 781.647.1234
*  Suite 227                               http://www.netsilicon.com
*  Waltham, MA 02452                       [e-mail]
*
*************************************************************************
*  $Name: Fusion 6.52 $
*  $Date: 2002/04/10 16:04:20 $
*  $Source: M:/psisrc/stack/incl/rcs/tcp.h $
*  $Revision: 1.31.2.2 $
**************************************************************************
*  File Description:  TCP (Transmission Control Protocol) defines
*
**************************************************************************/

#ifndef _TCP_
#define _TCP_

#include "config.h"
#include "ccdep.h"
#include "q.h"
#include "std.h"
#include "socket.h"
#include "timer.h"
#include "dsu.h"
#include "psu.h"
#include "so.h"
#include "ip.h"
#include "m.h"

/* TCP header */
typedef u8 TCPH_T;

#define TCPH_SPORT    0                 /* source port number, 2 bytes */
#define TCPH_DPORT    (TCPH_SPORT+2)    /* destination port number, 2 bytes */
#define TCPH_SEQNO    (TCPH_DPORT+2)    /* sequence number of first data byte, 4 bytes */
#define TCPH_ACKNO    (TCPH_SEQNO+4)    /* sequence number we next expect, 4 bytes */
#define TCPH_FLAGS    (TCPH_ACKNO+4)    /* 4 bits data offset : 12 bits flags, 2 bytes */
#define TCPH_WINDOW   (TCPH_FLAGS+2)    /* how much data can be accepted now, 2 bytes */
#define TCPH_CHECKSUM (TCPH_WINDOW+2)   /* ones complement checksum, 2 bytes */
#define TCPH_URGENT   (TCPH_CHECKSUM+2) /* urgent pointer, 2 bytes */

#define SIZEOF_TCPH_T (TCPH_URGENT+2)

/* Maximum size possible for the options in a TCP header. Limited by the fact
   that the data offset field is 4 bits (thus the highest value is 15, and its 
   unit is 32-bit words, thus the maximum data offset is 60), and the size of 
   the standard TCP header is 20 bytes */
#define TCP_MAX_SEG_OPTSIZE 40          

#if ( defined(TCP_SS_CA_FRETR_FREC) || defined(TCP_SELACK_ENHANCEMENTS) )
#define TCP_RETRANSMIT_ENHANCEMENTS
#endif

/*****************************************************************/
/* definitions pertaining to TCP options                         */
/*****************************************************************/

/* offsets from the beginning of any particular option into the
   fields of that option */
typedef u8 TCPO_T;
#define TCPO_KIND     0                 /* 1 byte */
#define TCPO_SIZE     (TCPO_KIND+1)     /* 1 byte */
#define TCPO_VAL      (TCPO_SIZE+1)     /* "size" bytes */

#define TCPO_EOL_KIND      0     /* End of option list */
/* no other fields */

#define TCPO_NOP_KIND      1     /* No operation, used for padding */
#define TCPO_NOP_LEN       1
/* no other fields */

#define TCPO_MSS_KIND      2     /* Maximum segment size */
#define TCPO_MSS_LEN       4     

#define TCPO_WSF_KIND      3     /* Window scale factor */
#define TCPO_WSF_LEN       3

#define TCPO_SACK_PERMITTED_KIND 4     /* Selective-Acknowledgements permitted */
#define TCPO_SACK_PERMITTED_LEN  2

#define TCPO_SACK_KIND     5           /* Selective Acknowledgement option */
/* Length of this option is variable, depending on how many SACKS are included */
#define TCPO_SACK_BLOCK_SIZE 8         /* Size of each block in a SACK option */

#define TCPO_TMSTMP_KIND   8     /* Time-Stamp */
#define TCPO_TMSTMP_LEN    10  
#define TCPO_TMSTMP_TSVAL  (TCPO_VAL)  /* 4 bytes in length */
#define TCPO_TMSTMP_TSECR  (TCPO_TMSTMP_TSVAL + 4)

/*******************************************************/
/* Options related to Transaction TCP                  */

#define TCPO_CC_KIND       11     /* Connection Count */
#define TCPO_CC_LEN        6
#define TCPO_CC_VAL        (TCPO_VAL)  /* 4 bytes in length */

#define TCPO_CCNEW_KIND    12     /* Connection Count (new) */
#define TCPO_CCNEW_LEN     6     
#define TCPO_CCNEW_VAL     (TCPO_VAL)  /* 4 bytes in length */

#define TCPO_CCECHO_KIND   13     /* Connection Count (new) */
#define TCPO_CCECHO_LEN    6     
#define TCPO_CCECHO_VAL    (TCPO_VAL)  /* 4 bytes in length */

/* Must update the following if any higher-numbered kinds are added */
#define TCPO_HIGHEST_KIND TCPO_CCECHO_KIND



#define TCP_DRMSS       536     /* Default Receive Maximum Segment Size, as per 
                                   RFC 1122, section 4.2.2.6 */

/* flags in TCP header ('tcph_flags') */
#define URG     ((u16)0x0020)   /* URGent pointer is significant */
#define ACK     ((u16)0x0010)   /* ACKnowledgement field is significant */
#define PSH     ((u16)0x0008)   /* PuSH function active in this segment */
#define RST     ((u16)0x0004)   /* connection ReSeT directive */
#define SYN     ((u16)0x0002)   /* SYNchronize seq numbers directive */
#define FIN     ((u16)0x0001)   /* FINished, no more data from sender, start close */

#define FLAG_MASK       ((u16)0x0FFF)   /* top 4 bits is data offset */
#define RSVD_FLGS       ((u16)0x0FC0)   /* these bits are reserved */

/* macros to test the states of flags */
#define URG_ON(f)       bT1((f), URG)
#define URG_OFF(f)      bF1((f), URG)
#define ACK_ON(f)       bT1((f), ACK)
#define ACK_OFF(f)      bF1((f), ACK)
#define PSH_ON(f)       bT1((f), PSH)
#define PSH_OFF(f)      bF1((f), PSH)
#define RST_ON(f)       bT1((f), RST)
#define RST_OFF(f)      bF1((f), RST)
#define SYN_ON(f)       bT1((f), SYN)
#define SYN_OFF(f)      bF1((f), SYN)
#define FIN_ON(f)       bT1((f), FIN)
#define FIN_OFF(f)      bF1((f), FIN)

/* length of TCP header */
#define tcphl(tcphp)    ((NetToHost16(&(tcphp)[TCPH_FLAGS]) >> 10) & 0x3C)
#define TCPHL tcphl

/* length of options part of TCP header */
#define TCPHOPTL(tcphp)   ( TCPHL(tcphp) - SIZEOF_TCPH_T)

/* pointer to the beginning of the options part of TCP header (should only be
   used if actually is an options part, i.e.mTCPHOPTL is non-zero */
#define TCPHOPTPTR(tcphp) (&( ( ((char *)tcphp)[SIZEOF_TCPH_T]) ) )

#ifdef TCP_SELACK_ENHANCEMENTS
/* Definitions pertaining to selective ack processing */

/* most SACK blocks that can fit into the options field of a TCP header which
   is devoid of any other options */
#define MAX_NUM_OUT_SACK_BLOCKS 4

/* The maximum number of incoming SACK blocks that Fusion will remember for a
   connection. */
#define MAX_NUM_IN_SACK_BLOCKS  8

/* structure of information from which a single SACK block option can be constructed */
typedef struct _tcp_sack_block_ {
   u32 begin_seqno;
   u32 end_seqno;
} tcp_sack_block_;
#endif /* TCP_SELACK_ENHANCEMENTS */


#define MOD32   /* for tcpsv_t */

#ifndef _MODULO_
#include "modulo.h"
#endif

#ifdef  SV_SKEPTIC

#define MAXREF  20
#define sv_bind(svp, ref, m_ok) _sv_bind(svp, ref, m_ok)
#define sv_detach(svp, ref, m_ok)       _sv_detach(svp, ref, m_ok)
#else
/* #define sv_bind(svp, ref, m_ok) _sv_bind(svp)    */
#define sv_bind(svp,ref,m_ok) (svp)->sv_refcnt++;
#define sv_detach(svp, ref, m_ok)       _sv_detach(svp)

#endif

/* Transmission Control Protocol Statistics Record */
typedef struct tcpsr_s  {
    u32     sr_avgbpc;      /* current (smoothed) average bytes / click */
    u8      sr_nsamples;    /* # of samples in the above average */
    u8      sr_1pad;
    u16     sr_flags;       /* status and control (see below) */
} tcpsr_t;

/* values of 'sr_flags' */
/* no special ones yet; some values of 'sv_rsflags' (below) also apply */


#ifdef TCP_TRANSACTION_TCP
#include "tcptrans.h"
#endif

/* Transmission Control Protocol State Vector */
typedef struct tcpsv_t  {  /* TCP state vector */
    q       sv_q;           /* queue of active state vectors */
    ipa     sv_src;         /* source address */
    ipa     sv_dest;        /* destination address */
    u16     sv_state;       /* state of connection */
    u16     sv_refcnt;      /* state vector reference count */
    u16     sv_flags;       /* historical state & pending actions */
	u16		sv_flags2;      /* More flags -- used separate u16 instead of changing 
							   sv_flags into u32 so that the existing flag checks
							   wouldn't cause 32-bit fetches -- maybe saves performance
							   loss */
	u16		sv_rcv_mss;     /* The receive MSS which has been set by a the
							   TCP_SET_RCV_MSS socket option. If this option has
							   been set, then this value will be advertised in the 
							   outgoing SYN instead of using the send MSS value */

#ifdef IP_RFC_1191
    u16		sv_peer_mss;    /* The MSS option value that was received from the peer 
							   (if any) in a SYN segment. Must be remembered because
							   we not never adjust our operational send MSS larger
							   than this (e.g., as a result of path MTU discovery
							   notifications). */
#endif /* IP_RFC_1191 */
    u16     sv_mss;         /* max. segment size (not including standard TCP header) */
	u16		sv_mssd;		/* maximum user data size in a maximum-sized segment 
							   (mss - length of the options field) -- included for
							   performance purposes, so that this value doesn't
							   have to be determined on a per-segment basis, involving
							   computations and function calls). This value is set
							   at the same time as sv_mss, and it is assumed that
							   all incoming and outgoing data segments will have the
							   same-sized options field */
	u16		sv_dseg_options; /* contains a bitmask of the options that will be present
							    in data segments on this connection. Present for the same
								reason as sv_mssd -- to minimize need for per-segment
								CPU-cosnuming function calls */
	u16		sv_mss_m_len;   /* message length that will be allocated for 
							    outgoing segements with mss worth of data */
    u32     sv_sq_max;      /* max size of the socket send queue for this TCP
                               connection. If the sq_max is adjusted downward
                               in response to a source quench, it will gradually
                               be adjusted upward back to this value */
    u32     sv_rq_max;      /* size of the socket receive queue for this TCP connection.*/
#ifdef SOCKET_USE_OLD_SOCKOPT_FUNCTIONS
    u16     sv_soptions;    /* copy of 'so_options' from socket */
#else
    u32     sv_soptions;    /* copy of 'so_options' from socket */
#endif
    u8      sv_tos;         /* copy of 'ipsu.ipsu_tos' from socket */
    u8      sv_prec;        /* precedence */
    u16     sv_err;         /* error which terminated this state vector */
    u16     sv_soindx;      /* socket index (for validation of sv_sop) */
    so_t    * sv_sop;       /* pointer to the socket this is attached to */
    /* These variables defined on pgs. [70..71] MIL-STD-1778 */
    m32     sv_snxt;        /* Send_NXT */
    m32     sv_suna;        /* Send_UNA */
    m32     sv_surg;        /* Send_URG */
    m32     sv_spsh;        /* Send_PuSH */
    m32     sv_rnxt;        /* Recv_NeXT */
    m32     sv_rurg;        /* Recv_URG */
    m32     sv_read;        /* Next byte for ULP to read (used for urgent data processing) */
    m32     sv_sisn;        /* Send_Initial_Sequence_Number */
    u32     sv_swnd;        /* Send_WNDw */
#ifdef TCP_SS_CA_FRETR_FREC 
    u32     sv_cwnd;        /* Congestion window for slow start/congestion avoidance */
	u32		sv_ssthresh;     /* Slow start threshold for slow start/congestion avoidance */
#define TCP_OPERATIONAL_SEND_WINDOW(s) ( min(s->sv_swnd, s->sv_cwnd) )
#endif
#ifdef TCP_WND_SCALE
	u16		sv_swndscale;   /* Send window scale */
#endif
    IPOS_T  sv_sec[SIZEOF_IPOS_T]; /* security structure */

    /* (re)transmission smarts */
    struct tcb * sv_rextcb; /* retransmission timer */