new_ip.c

mcf5307实验源代码

/*************************************************************************/
/*                                                                       */
/*    CopyrIght (c)  1993 - 1996 Accelerated Technology, Inc.            */
/*                                                                       */
/* PROPRIETARY RIGHTS of Accelerated Technology are involved in the      */
/* subject matter of this material.  All manufacturing, reproduction,    */
/* use, and sales rights pertaining to this subject matter are governed  */
/* by the license agreement.  The recipient of this software implicitly  */
/* accepts the terms of the license.                                     */
/*                                                                       */
/*************************************************************************/
/******************************************************************************/
/*                                                                            */
/* FILENAME                                                 VERSION           */
/*                                                                            */
/*  NEW_IP.C                                                  3.2             */
/*                                                                            */
/* DESCRIPTION                                                                */
/*                                                                            */
/*  This file contains the source for utility routines used by many           */
/*  of the TCP/IP files.  Formerly, they were in assembly language.           */
/*  They have been converted to C files for portability.                      */
/*                                                                            */
/* AUTHOR                                                                     */
/*                                                                            */
/*  Barbara G. Harwell, Accelerated Technology Inc.                           */
/*                                                                            */
/* DATA STRUCTURES                                                            */
/*                                                                            */
/*  No data structures defined in this file.                                  */
/*                                                                            */
/* FUNCTIONS                                                                  */
/*                                                                            */
/*     ipcheck                  Checksums an IP header                        */
/*     tcpcheck                 Checksums a TCP header                        */
/*     longswap                 Swaps 4 bytes of a long number                */
/*     intswap                  Swaps 2 bytes of a number                     */
/*     comparen                 Compares 2 strings for equality               */
/*                                                                            */
/* DEPENDENCIES                                                               */
/*                                                                            */
/*      NUCLEUS.H                                                             */
/*      EXTERNS.H                                                             */
/*                                                                            */
/* HISTORY                                                                    */
/*                                                                            */
/*    NAME               DATE        REMARKS                                  */
/*                                                                            */
/*  Barbara G. Harwell   10/06/92   Initial version.                          */
/*                                                                            */
/******************************************************************************/

#ifdef PLUS
  #include "nucleus.h"
#else
  #include "nu_defs.h"    /* added during ATI mods - 10/20/92, bgh */
  #include "nu_extr.h"
#endif

#include "externs.h"

#ifdef MSC
#include<time.h>
#endif

#if !(IPCHECK_ASM)
/************************************************************************/
/*                                                                      */
/*  FUNCTION                                "ipcheck"                   */
/*                                                                      */
/*                                                                      */
/*  DESCRIPTION                                                         */
/*                                                                      */
/*      This function checksums an IP header.                           */
/*                                                                      */
/*  AUTHOR                                                              */
/*                                                                      */
/*      B. Harwell,  Accelerated Technology                             */
/*                                                                      */
/*  HISTORY                                                             */
/*                                                                      */
/*      created - 12/22/92                                              */
/*                                                                      */
/*  CALLED FROM                                                         */
/*                                                                      */
/*      IP.C                                                            */
/*      TCP.C                                                           */
/*      UDP.C                                                           */
/*                                                                      */
/*  ROUTINES CALLED                                                     */
/*                                                                      */
/*      N/A                                                             */
/*                                                                      */
/*  INPUTS                                                              */
/*                                                                      */
/*      header                   Pointer to structure to be checksummed */
/*      length                   Length of header structure             */
/*                                                                      */
/*  OUTPUTS                                                             */
/*                                                                      */
/*      sum                      Checksum value of structure            */
/*                                                                      */
/************************************************************************/
uint16 ipcheck (uint16 *header, uint16 length)
{
    uint32 sum;

    for (sum = 0; length > 0; length--)
    {
         sum += *header++;
         /* check for a carry over 16 bits */
    }

    sum = (sum >> 16) + (sum & 0xffff);
    sum += (sum >> 16);
    return ((int16)~sum);
}
#endif /* IPCHECK_ASM */

#if !(TCPCHECK_ASM)
/************************************************************************/
/*                                                                      */
/*  FUNCTION                                "tcpcheck"                  */
/*                                                                      */
/*                                                                      */
/*  DESCRIPTION                                                         */
/*                                                                      */
/*      This function checksums a TCP header.                           */
/*                                                                      */
/*  AUTHOR                                                              */
/*                                                                      */
/*      B. Harwell,  Accelerated Technology                             */
/*                                                                      */
/*  HISTORY                                                             */
/*                                                                      */
/*      created - 12/22/92                                              */
/*                                                                      */
/*  CALLED FROM                                                         */
/*                                                                      */
/*      IP.C                                                            */
/*      TCP.C                                                           */
/*      UDP.C                                                           */
/*                                                                      */
/*  ROUTINES CALLED                                                     */
/*                                                                      */
/*      N/A                                                             */
/*                                                                      */
/*  INPUTS                                                              */
/*                                                                      */
/*      pseudoheader             Pointer to header to be checksummed    */
/*      tcpheader                Pointer to structure to be checksummed */
/*      length                   Length of tcpheader structure          */
/*                                                                      */
/*  OUTPUTS                                                             */
/*                                                                      */
/*      sum                      Checksum value of structure            */
/*                                                                      */
/************************************************************************/
uint16 tcpcheck (uint16 *pseudoheader, uint16 *tcpheader, uint16 length)
{
    register uint32 sum =0;
    register uint16 *pshdr = pseudoheader;
    register uint16 *tcphdr = tcpheader;

    /*  This used to be a loop.  The loop was removed to save a few
        cycles.  The header length is always 6 16-bit words.  */
    sum += *pshdr++;
    sum += *pshdr++;
    sum += *pshdr++;
    sum += *pshdr++;
    sum += *pshdr++;
    sum += *pshdr++;

    /*  Code to pad for the blank byte on odd number TCP packet length.  */
    if (length % 2)
    {
        ((char *)tcphdr)[length] = 0;
        length += 1;
    }

    /*  Make into 16-bit entities not bytes.  */
    length >>= 1;

    for (; length > 0; length--)
    {
        sum += *tcphdr++;
    }

    sum = (sum >> 16) + (sum & 0xffff);
    sum += (sum >> 16);
    return ((int16)~sum);
}
#endif /* !(TCPCHECK_ASM) */

#if !(LONGSWAP_ASM)
/************************************************************************/
/*                                                                      */
/*  FUNCTION                                "longswap"                  */
/*                                                                      */
/*                                                                      */
/*  DESCRIPTION                                                         */
/*                                                                      */
/*      This function swaps 4 bytes of a long number.                   */
/*                                                                      */