/* | |
* Copyright (c) 2001-2004 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> | |
* | |
*/ | |
/* inet6.c | |
* | |
* Functions common to all TCP/IP modules, such as the Internet checksum and the | |
* byte order functions. | |
* | |
*/ | |
#include "lwip/opt.h" | |
#include "lwip/def.h" | |
#include "lwip/inet.h" | |
/* 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. | |
* | |
* For now, this is not optimized. Must be optimized for the particular processor | |
* arcitecture on which it is to run. Preferebly coded in assembler. | |
*/ | |
static u32_t | |
chksum(void *dataptr, u16_t len) | |
{ | |
u16_t *sdataptr = dataptr; | |
u32_t acc; | |
for(acc = 0; len > 1; len -= 2) { | |
acc += *sdataptr++; | |
} | |
/* add up any odd byte */ | |
if (len == 1) { | |
acc += htons((u16_t)(*(u8_t *)dataptr) << 8); | |
} | |
return acc; | |
} | |
/* inet_chksum_pseudo: | |
* | |
* Calculates the pseudo Internet checksum used by TCP and UDP for a pbuf chain. | |
*/ | |
u16_t | |
inet_chksum_pseudo(struct pbuf *p, | |
struct ip_addr *src, struct ip_addr *dest, | |
u8_t proto, u32_t proto_len) | |
{ | |
u32_t acc; | |
struct pbuf *q; | |
u8_t swapped, i; | |
acc = 0; | |
swapped = 0; | |
for(q = p; q != NULL; q = q->next) { | |
acc += chksum(q->payload, q->len); | |
while (acc >> 16) { | |
acc = (acc & 0xffff) + (acc >> 16); | |
} | |
if (q->len % 2 != 0) { | |
swapped = 1 - swapped; | |
acc = ((acc & 0xff) << 8) | ((acc & 0xff00) >> 8); | |
} | |
} | |
if (swapped) { | |
acc = ((acc & 0xff) << 8) | ((acc & 0xff00) >> 8); | |
} | |
for(i = 0; i < 8; i++) { | |
acc += ((u16_t *)src->addr)[i] & 0xffff; | |
acc += ((u16_t *)dest->addr)[i] & 0xffff; | |
while (acc >> 16) { | |
acc = (acc & 0xffff) + (acc >> 16); | |
} | |
} | |
acc += (u16_t)htons((u16_t)proto); | |
acc += ((u16_t *)&proto_len)[0] & 0xffff; | |
acc += ((u16_t *)&proto_len)[1] & 0xffff; | |
while (acc >> 16) { | |
acc = (acc & 0xffff) + (acc >> 16); | |
} | |
return ~(acc & 0xffff); | |
} | |
/* inet_chksum: | |
* | |
* Calculates the Internet checksum over a portion of memory. Used primarely for IP | |
* and ICMP. | |
*/ | |
u16_t | |
inet_chksum(void *dataptr, u16_t len) | |
{ | |
u32_t acc, sum; | |
acc = chksum(dataptr, len); | |
sum = (acc & 0xffff) + (acc >> 16); | |
sum += (sum >> 16); | |
return ~(sum & 0xffff); | |
} | |
u16_t | |
inet_chksum_pbuf(struct pbuf *p) | |
{ | |
u32_t acc; | |
struct pbuf *q; | |
u8_t swapped; | |
acc = 0; | |
swapped = 0; | |
for(q = p; q != NULL; q = q->next) { | |
acc += chksum(q->payload, q->len); | |
while (acc >> 16) { | |
acc = (acc & 0xffff) + (acc >> 16); | |
} | |
if (q->len % 2 != 0) { | |
swapped = 1 - swapped; | |
acc = (acc & 0xff << 8) | (acc & 0xff00 >> 8); | |
} | |
} | |
if (swapped) { | |
acc = ((acc & 0xff) << 8) | ((acc & 0xff00) >> 8); | |
} | |
return ~(acc & 0xffff); | |
} | |