source: lib/checksum.c

4.0.1-hotfixescachetimestampsdevelopdpdk-ndagetsilivendag_formatrc-4.0.1rc-4.0.2rc-4.0.3rc-4.0.4ringdecrementfixringperformanceringtimestampfixes
Last change on this file was ee6e802, checked in by Shane Alcock <salcock@…>, 5 years ago

Updated copyright blurb on all source files

In some cases, this meant adding copyright blurbs to files that
had never had them before.

  • Property mode set to 100644
File size: 2.4 KB
Line 
1/*
2 *
3 * Copyright (c) 2007-2016 The University of Waikato, Hamilton, New Zealand.
4 * All rights reserved.
5 *
6 * This file is part of libtrace.
7 *
8 * This code has been developed by the University of Waikato WAND
9 * research group. For further information please see http://www.wand.net.nz/
10 *
11 * libtrace is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU Lesser General Public License as published by
13 * the Free Software Foundation; either version 3 of the License, or
14 * (at your option) any later version.
15 *
16 * libtrace is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
19 * GNU Lesser General Public License for more details.
20 *
21 * You should have received a copy of the GNU Lesser General Public License
22 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
23 *
24 *
25 */
26
27
28#include "checksum.h"
29
30uint32_t add_checksum(void *buffer, uint16_t length) {
31        uint32_t sum = 0;
32        uint16_t * buff = (uint16_t *) buffer;
33        uint16_t count = length;
34        uint16_t val;
35
36        while(count > 1 ) {
37                val = *buff;
38                sum += val;
39                buff ++;
40                count = count -2;
41        }
42
43        if(count > 0) {
44                sum += *(uint8_t *)buff;
45        }
46
47        return sum;
48}
49
50uint16_t finish_checksum(uint32_t sum) {
51        while (sum>>16) {
52                sum = (sum & 0xffff) + (sum >> 16);
53        }
54        return (uint16_t)~sum;
55}
56
57uint16_t checksum_buffer(void *buffer, uint16_t length) {
58
59        uint32_t sum = add_checksum(buffer, length);
60        return finish_checksum(sum);
61
62}
63
64uint32_t ipv4_pseudo_checksum(libtrace_ip_t *ip) {
65
66        uint32_t sum = 0;
67        uint16_t temp = 0;
68
69        sum += add_checksum(&ip->ip_src.s_addr,sizeof(uint32_t));
70        sum += add_checksum(&ip->ip_dst.s_addr,sizeof(uint32_t));
71
72        temp = htons(ip->ip_p);
73        sum += add_checksum(&temp, sizeof(uint16_t));
74
75        temp = htons(ntohs(ip->ip_len) - (ip->ip_hl * 4));
76        sum += add_checksum(&temp, sizeof(uint16_t));
77
78        return sum;     
79
80}
81
82uint32_t ipv6_pseudo_checksum(libtrace_ip6_t *ip) {
83
84        uint32_t sum = 0;
85        uint16_t temp = 0;
86
87        sum += add_checksum(&ip->ip_src.s6_addr,sizeof(struct in6_addr));
88        sum += add_checksum(&ip->ip_dst.s6_addr,sizeof(struct in6_addr));
89       
90        temp = ip->plen;
91        sum += add_checksum(&temp, sizeof(uint16_t));
92
93
94        temp = htons(ip->nxt);
95        sum += add_checksum(&temp, sizeof(uint16_t));
96
97
98        return sum;     
99
100}
101
102
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