compress.h

用于TM1300/PNX1300系列DSP（主要用于视频处理）的操作系统pSOS。包括全部源码

/* @(#) pSOSystem/PowerPC V2.1.2: drivers/slip/%compress.h 1.5 95/07/25 13:58:44 */
/************************************************************************/
/*                                                                      */
/*   MODULE: slcompress.h                                               */
/*   PRODUCT: pNA+                                                      */
/*   PURPOSE: definitions for VJ compression                            */
/*   DATE: 95/07/25                                                     */
/*                                                                      */
/*----------------------------------------------------------------------*/
/*                                                                      */
/*              Copyright 1993, Integrated Systems Inc.                 */
/*                      ALL RIGHTS RESERVED                             */
/*                                                                      */
/*   This computer program is the property of Integrated Systems Inc.   */
/*   Santa Clara, California, U.S.A. and may not be copied              */
/*   in any form or by any means, whether in part or in whole,          */
/*   except under license expressly granted by Integrated Systems Inc.  */
/*                                                                      */
/*   All copies of this program, whether in part or in whole, and       */
/*   whether modified or not, must display this and all other           */
/*   embedded copyright and ownership notices in full.                  */
/*                                                                      */
/*----------------------------------------------------------------------*/
/*                                                                      */
/* Global Procedures:                                                   */
/*                                                                      */
/*                                                                      */
/************************************************************************/
/*
 * Definitions for tcp compression routines.
 *
 * @(#) $Header: /tmp_mnt/homes/product1/network/slip68k/pss20c4/drivers/slip/RCS/compress.h,v 1.3 1993/12/01 00:28:00 mz Exp mz $ (LBL)
 *
 * Copyright (c) 1989, 1990, 1992 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by the University of California, Berkeley.  The name of the
 * University may not be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 *
 *  Van Jacobson ([e-mail]), Dec 31, 1989:
 *  - Initial distribution.
 */
#if defined(__cplusplus)
extern "C" {
#endif
 

#ifndef __SLCOMPRESS_H__
#define __SLCOMPRESS_H__

#ifndef _BSP_H
  #error Must inlcude bsp.h before slip/compress.h
#endif

/*======================================================================*/
/* CSLIP specific definitions                                           */
/*======================================================================*/
typedef unsigned char U_CHAR;
typedef unsigned short U_SHORT;
typedef unsigned long U_LONG;
typedef unsigned int  U_INT;
typedef char *CADDR_T;

#define LITTLE_ENDIAN   1234    /* least-significant byte first (vax) */
#define BIG_ENDIAN  4321    /* most-significant byte first (IBM, net) */
#define PDP_ENDIAN  3412    /* LSB first in word, MSW first in long (pdp) */

#if BSP_LITTLE_ENDIAN == YES
#define BYTE_ORDER LITTLE_ENDIAN
#else
#define BYTE_ORDER BIG_ENDIAN
#endif

struct mbuf
  {
  U_CHAR *m_off;     /* pointer to start of data */
  int    m_len;      /* length of data */
  };
#undef mtod
#define mtod(m, t) ((t)(m->m_off))

/*----------------------------------------------------------------------*/
/* IP header                                                            */
/*----------------------------------------------------------------------*/
#define IPVERSION 4
struct ip {
#if BYTE_ORDER == LITTLE_ENDIAN
    U_CHAR  ip_hl:4;        /* header length */
    U_CHAR  ip_v:4;         /* version */
#endif
#if BYTE_ORDER == BIG_ENDIAN
    U_CHAR  ip_v:4;         /* version */
    U_CHAR  ip_hl:4;        /* header length */
#endif
    U_CHAR  ip_tos;         /* type of service */
    U_SHORT ip_len;         /* total length */
    U_SHORT ip_id;          /* identification */
    U_SHORT ip_off;         /* fragment offset field */
#define IP_DF 0x4000            /* dont fragment flag */
#define IP_MF 0x2000            /* more fragments flag */
    U_CHAR  ip_ttl;         /* time to live */
    U_CHAR  ip_p;           /* protocol */
    U_SHORT ip_sum;         /* checksum */
    struct  in_addr ip_src,ip_dst;  /* source and dest address */
};

/*----------------------------------------------------------------------*/
/* TCP header                                                           */
/*----------------------------------------------------------------------*/
typedef U_LONG  tcp_seq;
struct tcphdr {
    U_SHORT th_sport;       /* source port */
    U_SHORT th_dport;       /* destination port */
    tcp_seq th_seq;         /* sequence number */
    tcp_seq th_ack;         /* acknowledgement number */
#if BYTE_ORDER == LITTLE_ENDIAN
    U_CHAR  th_x2:4;        /* (unused) */
    U_CHAR  th_off:4;       /* data offset */
#endif
#if BYTE_ORDER == BIG_ENDIAN
    U_CHAR  th_off:4;       /* data offset */
    U_CHAR  th_x2:4;        /* (unused) */
#endif
    U_CHAR  th_flags;
#define TH_FIN  0x01
#define TH_SYN  0x02
#define TH_RST  0x04
#define TH_PUSH 0x08
#define TH_ACK  0x10
#define TH_URG  0x20
    U_SHORT th_win;         /* window */
    U_SHORT th_sum;         /* checksum */
    U_SHORT th_urp;         /* urgent pointer */
};

#define MAX_STATES 16                /* must be > 2 and < 256 */
#define MAX_HDR 128     /* XXX 4bsd-ism: should really be 128 */

/*
 * Compressed packet format:
 *
 * The first octet contains the packet type (top 3 bits), TCP
 * 'push' bit, and flags that indicate which of the 4 TCP sequence
 * numbers have changed (bottom 5 bits).  The next octet is a
 * conversation number that associates a saved IP/TCP header with
 * the compressed packet.  The next two octets are the TCP checksum
 * from the original datagram.  The next 0 to 15 octets are
 * sequence number changes, one change per bit set in the header
 * (there may be no changes and there are two special cases where
 * the receiver implicitly knows what changed -- see below).
 *
 * There are 5 numbers which can change (they are always inserted
 * in the following order): TCP urgent pointer, window,
 * acknowlegement, sequence number and IP ID.  (The urgent pointer
 * is different from the others in that its value is sent, not the
 * change in value.)  Since typical use of SLIP links is biased
 * toward small packets (see comments on MTU/MSS below), changes
 * use a variable length coding with one octet for numbers in the
 * range 1 - 255 and 3 octets (0, MSB, LSB) for numbers in the
 * range 256 - 65535 or 0.  (If the change in sequence number or
 * ack is more than 65535, an uncompressed packet is sent.)
 */

/*
 * Packet types (must not conflict with IP protocol version)
 *
 * The top nibble of the first octet is the packet type.  There are
 * three possible types: IP (not proto TCP or tcp with one of the
 * control flags set); uncompressed TCP (a normal IP/TCP packet but
 * with the 8-bit protocol field replaced by an 8-bit connection id --
 * this type of packet syncs the sender & receiver); and compressed
 * TCP (described above).
 *
 * LSB of 4-bit field is TCP "PUSH" bit (a worthless anachronism) and
 * is logically part of the 4-bit "changes" field that follows.  Top
 * three bits are actual packet type.  For backward compatibility
 * and in the interest of conserving bits, numbers are chosen so the
 * IP protocol version number (4) which normally appears in this nibble
 * means "IP packet".
 */

/* packet types */
#define TYPE_IP 0x40
#define TYPE_UNCOMPRESSED_TCP 0x70
#define TYPE_COMPRESSED_TCP 0x80
#define TYPE_ERROR 0x00

/* Bits in first octet of compressed packet */
#define NEW_C   0x40    /* flag bits for what changed in a packet */
#define NEW_I   0x20
#define NEW_S   0x08
#define NEW_A   0x04
#define NEW_W   0x02
#define NEW_U   0x01

/* reserved, special-case values of above */
#define SPECIAL_I (NEW_S|NEW_W|NEW_U)       /* echoed interactive traffic */
#define SPECIAL_D (NEW_S|NEW_A|NEW_W|NEW_U) /* unidirectional data */
#define SPECIALS_MASK (NEW_S|NEW_A|NEW_W|NEW_U)

#define TCP_PUSH_BIT 0x10


/*
 * "state" data for each active tcp conversation on the wire.  This is
 * basically a copy of the entire IP/TCP header from the last packet
 * we saw from the conversation together with a small identifier
 * the transmit & receive ends of the line use to locate saved header.
 */
struct cstate {
    struct cstate *cs_next; /* next most recently used cstate (xmit only) */
    U_SHORT cs_hlen;    /* size of hdr (receive only) */
    U_CHAR cs_id;       /* connection # associated with this state */
    U_CHAR cs_filler;
    union {
        char csu_hdr[MAX_HDR];
        struct ip csu_ip;   /* ip/tcp hdr from most recent packet */
    } slcs_u;
};
#define cs_ip slcs_u.csu_ip
#define cs_hdr slcs_u.csu_hdr

/*
 * all the state data for one serial line (we need one of these
 * per line).
 */
struct slcompress {
    struct cstate *last_cs; /* most recently used tstate */
    U_CHAR last_recv;   /* last rcvd conn. id */
    U_CHAR last_xmit;   /* last sent conn. id */
    U_SHORT flags;
#ifndef SL_NO_STATS
    U_INT sls_packets;  /* outbound packets */
    U_INT sls_compressed;   /* outbound compressed packets */
    U_INT sls_searches; /* searches for connection state */
    U_INT sls_misses;   /* times couldn't find conn. state */
    U_INT sls_uncompressedin;/* inbound uncompressed packets */
    U_INT sls_compressedin; /* inbound compressed packets */
    U_INT sls_errorin;  /* inbound unknown type packets */
    U_INT sls_tossed;   /* inbound packets tossed because of error */
#endif
    struct cstate tstate[MAX_STATES];   /* xmit connection states */
    struct cstate rstate[MAX_STATES];   /* receive connection states */
};
/* flag values */
#define SLF_TOSS 1      /* tossing rcvd frames because of input err */

#ifdef __STDC__
extern  void slbcopy(U_CHAR *src0, U_CHAR *dst0, int length);
extern  void sl_compress_init(struct slcompress *);
extern  U_CHAR sl_compress_tcp(struct mbuf *, struct ip *, struct slcompress *, int);
extern  int sl_uncompress_tcp(U_CHAR **, int, U_INT, struct slcompress *);
#else
extern  void sl_compress_init();
extern  U_CHAR sl_compress_tcp();
extern  int sl_uncompress_tcp();
#endif

#endif /* __SLCOMPRESS_H__ */
 
#if defined(__cplusplus)
}
#endif