lwip-contrib-mac/ports/unix/lwip_chksum.c
2003-01-18 18:18:02 +00:00

74 lines
2.5 KiB
C

/*
* Copyright (c) 2001-2003 Swedish Institute of Computer Science.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
* SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
* OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
* OF SUCH DAMAGE.
*
* This file is part of the lwIP TCP/IP stack.
*
* Author: Adam Dunkels <adam@sics.se>
*
*/
#include "lwip/debug.h"
#include "lwip/arch.h"
#include "lwip/def.h"
#include "lwip/inet.h"
/*-----------------------------------------------------------------------------------*/
/* lwip_chksum:
*
* Sums up all 16 bit words in a memory portion. Also includes any odd byte.
* This function is used by the other checksum functions.
*
*/
/*-----------------------------------------------------------------------------------*/
#if 0
u16_t
lwip_chksum(void *dataptr, int len)
{
u32_t acc;
for(acc = 0; len > 1; len -= 2) {
acc += *((u16_t *)dataptr)++;
}
/* add up any odd byte */
if(len == 1) {
acc += htons((u16_t)((*(u8_t *)dataptr) & 0xff) << 8);
DEBUGF(INET_DEBUG, ("inet: chksum: odd byte %d\n", *(u8_t *)dataptr));
}
acc = (acc >> 16) + (acc & 0xffffUL);
if(acc & 0xffff0000 != 0) {
acc = (acc >> 16) + (acc & 0xffffUL);
}
return (u16_t)acc;
}
/*-----------------------------------------------------------------------------------*/
#endif