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[/] [openrisc/] [trunk/] [rtos/] [freertos-6.1.1/] [Demo/] [Common/] [ethernet/] [lwIP/] [core/] [inet6.c] - Blame information for rev 606

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Line No. Rev Author Line
1 606 jeremybenn
/*
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 * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
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 * All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without modification,
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 * are permitted provided that the following conditions are met:
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 *
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 * 1. Redistributions of source code must retain the above copyright notice,
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 *    this list of conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright notice,
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 *    this list of conditions and the following disclaimer in the documentation
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 *    and/or other materials provided with the distribution.
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 * 3. The name of the author may not be used to endorse or promote products
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 *    derived from this software without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
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 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
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 * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
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 * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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 * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
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 * OF SUCH DAMAGE.
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 *
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 * This file is part of the lwIP TCP/IP stack.
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 *
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 * Author: Adam Dunkels <adam@sics.se>
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 *
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 */
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/* inet6.c
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 *
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 * Functions common to all TCP/IP modules, such as the Internet checksum and the
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 * byte order functions.
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 *
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 */
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#include "lwip/opt.h"
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#include "lwip/def.h"
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#include "lwip/inet.h"
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/* chksum:
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 *
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 * Sums up all 16 bit words in a memory portion. Also includes any odd byte.
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 * This function is used by the other checksum functions.
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 *
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 * For now, this is not optimized. Must be optimized for the particular processor
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 * arcitecture on which it is to run. Preferebly coded in assembler.
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 */
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static u32_t
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chksum(void *dataptr, u16_t len)
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{
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  u16_t *sdataptr = dataptr;
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  u32_t acc;
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  for(acc = 0; len > 1; len -= 2) {
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    acc += *sdataptr++;
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  }
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  /* add up any odd byte */
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  if (len == 1) {
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    acc += htons((u16_t)(*(u8_t *)dataptr) << 8);
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  }
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  return acc;
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}
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/* inet_chksum_pseudo:
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 *
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 * Calculates the pseudo Internet checksum used by TCP and UDP for a pbuf chain.
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 */
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u16_t
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inet_chksum_pseudo(struct pbuf *p,
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       struct ip_addr *src, struct ip_addr *dest,
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       u8_t proto, u32_t proto_len)
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{
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  u32_t acc;
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  struct pbuf *q;
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  u8_t swapped, i;
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  acc = 0;
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  swapped = 0;
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  for(q = p; q != NULL; q = q->next) {
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    acc += chksum(q->payload, q->len);
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    while (acc >> 16) {
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      acc = (acc & 0xffff) + (acc >> 16);
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    }
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    if (q->len % 2 != 0) {
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      swapped = 1 - swapped;
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      acc = ((acc & 0xff) << 8) | ((acc & 0xff00) >> 8);
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    }
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  }
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  if (swapped) {
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    acc = ((acc & 0xff) << 8) | ((acc & 0xff00) >> 8);
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  }
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  for(i = 0; i < 8; i++) {
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    acc += ((u16_t *)src->addr)[i] & 0xffff;
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    acc += ((u16_t *)dest->addr)[i] & 0xffff;
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    while (acc >> 16) {
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      acc = (acc & 0xffff) + (acc >> 16);
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    }
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  }
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  acc += (u16_t)htons((u16_t)proto);
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  acc += ((u16_t *)&proto_len)[0] & 0xffff;
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  acc += ((u16_t *)&proto_len)[1] & 0xffff;
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  while (acc >> 16) {
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    acc = (acc & 0xffff) + (acc >> 16);
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  }
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  return ~(acc & 0xffff);
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}
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/* inet_chksum:
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 *
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 * Calculates the Internet checksum over a portion of memory. Used primarely for IP
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 * and ICMP.
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 */
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u16_t
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inet_chksum(void *dataptr, u16_t len)
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{
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  u32_t acc, sum;
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  acc = chksum(dataptr, len);
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  sum = (acc & 0xffff) + (acc >> 16);
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  sum += (sum >> 16);
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  return ~(sum & 0xffff);
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}
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u16_t
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inet_chksum_pbuf(struct pbuf *p)
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{
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  u32_t acc;
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  struct pbuf *q;
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  u8_t swapped;
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  acc = 0;
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  swapped = 0;
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  for(q = p; q != NULL; q = q->next) {
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    acc += chksum(q->payload, q->len);
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    while (acc >> 16) {
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      acc = (acc & 0xffff) + (acc >> 16);
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    }
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    if (q->len % 2 != 0) {
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      swapped = 1 - swapped;
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      acc = (acc & 0xff << 8) | (acc & 0xff00 >> 8);
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    }
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  }
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  if (swapped) {
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    acc = ((acc & 0xff) << 8) | ((acc & 0xff00) >> 8);
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  }
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  return ~(acc & 0xffff);
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}
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