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/*
* This file is part of libtrace
*
* Copyright (c) 2007-2013 The University of Waikato, Hamilton,
* New Zealand.
*
* Authors: Daniel Lawson
* Perry Lorier
* Shane Alcock
*
* All rights reserved.
*
* This code has been developed by the University of Waikato WAND
* research group. For further information please see http://www.wand.net.nz/
*
* libtrace is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* libtrace is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with libtrace; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* $Id$
*
*/
#include "checksum.h"
uint32_t add_checksum(void *buffer, uint16_t length) {
uint32_t sum = 0;
uint16_t * buff = (uint16_t *) buffer;
uint16_t count = length;
uint16_t val;
while(count > 1 ) {
val = *buff;
sum += val;
buff ++;
count = count -2;
}
if(count > 0) {
sum += *(uint8_t *)buff;
}
return sum;
}
uint16_t finish_checksum(uint32_t sum) {
while (sum>>16) {
sum = (sum & 0xffff) + (sum >> 16);
}
return (uint16_t)~sum;
}
uint16_t checksum_buffer(void *buffer, uint16_t length) {
uint32_t sum = add_checksum(buffer, length);
return finish_checksum(sum);
}
uint32_t ipv4_pseudo_checksum(libtrace_ip_t *ip) {
uint32_t sum = 0;
uint16_t temp = 0;
sum += add_checksum(&ip->ip_src.s_addr,sizeof(uint32_t));
sum += add_checksum(&ip->ip_dst.s_addr,sizeof(uint32_t));
temp = htons(ip->ip_p);
sum += add_checksum(&temp, sizeof(uint16_t));
temp = htons(ntohs(ip->ip_len) - (ip->ip_hl * 4));
sum += add_checksum(&temp, sizeof(uint16_t));
return sum;
}
uint32_t ipv6_pseudo_checksum(libtrace_ip6_t *ip) {
uint32_t sum = 0;
uint16_t temp = 0;
sum += add_checksum(&ip->ip_src.s6_addr,sizeof(struct in6_addr));
sum += add_checksum(&ip->ip_dst.s6_addr,sizeof(struct in6_addr));
temp = ip->plen;
sum += add_checksum(&temp, sizeof(uint16_t));
temp = htons(ip->nxt);
sum += add_checksum(&temp, sizeof(uint16_t));
return sum;
}
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