FreeRTOS/Common/ethernet/lwIP/core/inet6.c

   1 /*
   2  * Copyright (c) 2001-2004 Swedish Institute of Computer Science.
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without modification,
   6  * are permitted provided that the following conditions are met:
   7  *
   8  * 1. Redistributions of source code must retain the above copyright notice,
   9  *    this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright notice,
  11  *    this list of conditions and the following disclaimer in the documentation
  12  *    and/or other materials provided with the distribution.
  13  * 3. The name of the author may not be used to endorse or promote products
  14  *    derived from this software without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
  17  * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  18  * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
  19  * SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  20  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
  21  * OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  22  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  23  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
  24  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
  25  * OF SUCH DAMAGE.
  26  *
  27  * This file is part of the lwIP TCP/IP stack.
  28  *
  29  * Author: Adam Dunkels <adam@sics.se>
  30  *
  31  */
  32
  33
  34 /* inet6.c
  35  *
  36  * Functions common to all TCP/IP modules, such as the Internet checksum and the
  37  * byte order functions.
  38  *
  39  */
  40
  41
  42 #include "lwip/opt.h"
  43
  44 #include "lwip/def.h"
  45 #include "lwip/inet.h"
  46
  47
  48
  49 /* chksum:
  50  *
  51  * Sums up all 16 bit words in a memory portion. Also includes any odd byte.
  52  * This function is used by the other checksum functions.
  53  *
  54  * For now, this is not optimized. Must be optimized for the particular processor
  55  * arcitecture on which it is to run. Preferebly coded in assembler.
  56  */
  57
  58 static u32_t
  59 chksum(void *dataptr, u16_t len)
  60 {
  61   u16_t *sdataptr = dataptr;
  62   u32_t acc;
  63
  64
  65   for(acc = 0; len > 1; len -= 2) {
  66     acc += *sdataptr++;
  67   }
  68
  69   /* add up any odd byte */
  70   if (len == 1) {
  71     acc += htons((u16_t)(*(u8_t *)dataptr) << 8);
  72   }
  73
  74   return acc;
  75
  76 }
  77
  78 /* inet_chksum_pseudo:
  79  *
  80  * Calculates the pseudo Internet checksum used by TCP and UDP for a pbuf chain.
  81  */
  82
  83 u16_t
  84 inet_chksum_pseudo(struct pbuf *p,
  85        struct ip_addr *src, struct ip_addr *dest,
  86        u8_t proto, u32_t proto_len)
  87 {
  88   u32_t acc;
  89   struct pbuf *q;
  90   u8_t swapped, i;
  91
  92   acc = 0;
  93   swapped = 0;
  94   for(q = p; q != NULL; q = q->next) {
  95     acc += chksum(q->payload, q->len);
  96     while (acc >> 16) {
  97       acc = (acc & 0xffff) + (acc >> 16);
  98     }
  99     if (q->len % 2 != 0) {
 100       swapped = 1 - swapped;
 101       acc = ((acc & 0xff) << 8) | ((acc & 0xff00) >> 8);
 102     }
 103   }
 104
 105   if (swapped) {
 106     acc = ((acc & 0xff) << 8) | ((acc & 0xff00) >> 8);
 107   }
 108
 109   for(i = 0; i < 8; i++) {
 110     acc += ((u16_t *)src->addr)[i] & 0xffff;
 111     acc += ((u16_t *)dest->addr)[i] & 0xffff;
 112     while (acc >> 16) {
 113       acc = (acc & 0xffff) + (acc >> 16);
 114     }
 115   }
 116   acc += (u16_t)htons((u16_t)proto);
 117   acc += ((u16_t *)&proto_len)[0] & 0xffff;
 118   acc += ((u16_t *)&proto_len)[1] & 0xffff;
 119
 120   while (acc >> 16) {
 121     acc = (acc & 0xffff) + (acc >> 16);
 122   }
 123   return ~(acc & 0xffff);
 124 }
 125
 126 /* inet_chksum:
 127  *
 128  * Calculates the Internet checksum over a portion of memory. Used primarely for IP
 129  * and ICMP.
 130  */
 131
 132 u16_t
 133 inet_chksum(void *dataptr, u16_t len)
 134 {
 135   u32_t acc, sum;
 136
 137   acc = chksum(dataptr, len);
 138   sum = (acc & 0xffff) + (acc >> 16);
 139   sum += (sum >> 16);
 140   return ~(sum & 0xffff);
 141 }
 142
 143 u16_t
 144 inet_chksum_pbuf(struct pbuf *p)
 145 {
 146   u32_t acc;
 147   struct pbuf *q;
 148   u8_t swapped;
 149
 150   acc = 0;
 151   swapped = 0;
 152   for(q = p; q != NULL; q = q->next) {
 153     acc += chksum(q->payload, q->len);
 154     while (acc >> 16) {
 155       acc = (acc & 0xffff) + (acc >> 16);
 156     }
 157     if (q->len % 2 != 0) {
 158       swapped = 1 - swapped;
 159       acc = (acc & 0xff << 8) | (acc & 0xff00 >> 8);
 160     }
 161   }
 162
 163   if (swapped) {
 164     acc = ((acc & 0xff) << 8) | ((acc & 0xff00) >> 8);
 165   }
 166   return ~(acc & 0xffff);
 167 }
 168