1*0Sstevel@tonic-gate /*
2*0Sstevel@tonic-gate * CDDL HEADER START
3*0Sstevel@tonic-gate *
4*0Sstevel@tonic-gate * The contents of this file are subject to the terms of the
5*0Sstevel@tonic-gate * Common Development and Distribution License, Version 1.0 only
6*0Sstevel@tonic-gate * (the "License"). You may not use this file except in compliance
7*0Sstevel@tonic-gate * with the License.
8*0Sstevel@tonic-gate *
9*0Sstevel@tonic-gate * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10*0Sstevel@tonic-gate * or http://www.opensolaris.org/os/licensing.
11*0Sstevel@tonic-gate * See the License for the specific language governing permissions
12*0Sstevel@tonic-gate * and limitations under the License.
13*0Sstevel@tonic-gate *
14*0Sstevel@tonic-gate * When distributing Covered Code, include this CDDL HEADER in each
15*0Sstevel@tonic-gate * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16*0Sstevel@tonic-gate * If applicable, add the following below this CDDL HEADER, with the
17*0Sstevel@tonic-gate * fields enclosed by brackets "[]" replaced with your own identifying
18*0Sstevel@tonic-gate * information: Portions Copyright [yyyy] [name of copyright owner]
19*0Sstevel@tonic-gate *
20*0Sstevel@tonic-gate * CDDL HEADER END
21*0Sstevel@tonic-gate */
22*0Sstevel@tonic-gate /*
23*0Sstevel@tonic-gate * Copyright (c) 1996-2001 by Sun Microsystems, Inc.
24*0Sstevel@tonic-gate * All rights reserved.
25*0Sstevel@tonic-gate */
26*0Sstevel@tonic-gate
27*0Sstevel@tonic-gate #pragma ident "%Z%%M% %I% %E% SMI"
28*0Sstevel@tonic-gate
29*0Sstevel@tonic-gate #include <sys/types.h>
30*0Sstevel@tonic-gate #include <strings.h>
31*0Sstevel@tonic-gate #include <netinet/in.h>
32*0Sstevel@tonic-gate #include "v4_sum_impl.h"
33*0Sstevel@tonic-gate
34*0Sstevel@tonic-gate /*
35*0Sstevel@tonic-gate * RFC 768 pseudo header. Used in calculating UDP checksums.
36*0Sstevel@tonic-gate */
37*0Sstevel@tonic-gate struct pseudo_udp {
38*0Sstevel@tonic-gate struct in_addr src;
39*0Sstevel@tonic-gate struct in_addr dst;
40*0Sstevel@tonic-gate uint8_t notused; /* always zero */
41*0Sstevel@tonic-gate uint8_t proto; /* protocol used */
42*0Sstevel@tonic-gate uint16_t len; /* UDP len */
43*0Sstevel@tonic-gate };
44*0Sstevel@tonic-gate
45*0Sstevel@tonic-gate /*
46*0Sstevel@tonic-gate * One's complement checksum of pseudo header, udp header, and data.
47*0Sstevel@tonic-gate * Must be MT SAFE.
48*0Sstevel@tonic-gate */
49*0Sstevel@tonic-gate uint16_t
udp_chksum(struct udphdr * udph,const struct in_addr * src,const struct in_addr * dst,uint8_t proto)50*0Sstevel@tonic-gate udp_chksum(struct udphdr *udph, const struct in_addr *src,
51*0Sstevel@tonic-gate const struct in_addr *dst, uint8_t proto)
52*0Sstevel@tonic-gate {
53*0Sstevel@tonic-gate struct pseudo_udp ck;
54*0Sstevel@tonic-gate uint16_t *end_pseudo_hdr = (uint16_t *)(&ck + 1);
55*0Sstevel@tonic-gate uint16_t *sp = (uint16_t *)&ck;
56*0Sstevel@tonic-gate uint_t sum = 0;
57*0Sstevel@tonic-gate uint16_t cnt;
58*0Sstevel@tonic-gate
59*0Sstevel@tonic-gate /*
60*0Sstevel@tonic-gate * Start on the pseudo header. Note that pseudo_udp already takes
61*0Sstevel@tonic-gate * acount for the udphdr...
62*0Sstevel@tonic-gate */
63*0Sstevel@tonic-gate
64*0Sstevel@tonic-gate bzero(&ck, sizeof (ck));
65*0Sstevel@tonic-gate
66*0Sstevel@tonic-gate /* struct copies */
67*0Sstevel@tonic-gate ck.src = *src;
68*0Sstevel@tonic-gate ck.dst = *dst;
69*0Sstevel@tonic-gate ck.len = udph->uh_ulen;
70*0Sstevel@tonic-gate ck.proto = proto;
71*0Sstevel@tonic-gate
72*0Sstevel@tonic-gate /*
73*0Sstevel@tonic-gate * If the packet is an odd length, zero the pad byte for checksum
74*0Sstevel@tonic-gate * purposes [doesn't hurt data]
75*0Sstevel@tonic-gate */
76*0Sstevel@tonic-gate
77*0Sstevel@tonic-gate cnt = ntohs(ck.len) + sizeof (ck);
78*0Sstevel@tonic-gate if (cnt & 1) {
79*0Sstevel@tonic-gate ((caddr_t)udph)[ntohs(udph->uh_ulen)] = '\0';
80*0Sstevel@tonic-gate cnt++; /* make even */
81*0Sstevel@tonic-gate }
82*0Sstevel@tonic-gate
83*0Sstevel@tonic-gate for (cnt >>= 1; cnt != 0; cnt--) {
84*0Sstevel@tonic-gate
85*0Sstevel@tonic-gate sum += *sp++;
86*0Sstevel@tonic-gate if (sum >= BIT_WRAP) {
87*0Sstevel@tonic-gate /* Wrap carries into low bit */
88*0Sstevel@tonic-gate sum -= BIT_WRAP;
89*0Sstevel@tonic-gate sum++;
90*0Sstevel@tonic-gate }
91*0Sstevel@tonic-gate
92*0Sstevel@tonic-gate /*
93*0Sstevel@tonic-gate * If we've finished checking the pseudo-header, move
94*0Sstevel@tonic-gate * onto the udp header and data.
95*0Sstevel@tonic-gate */
96*0Sstevel@tonic-gate
97*0Sstevel@tonic-gate if (sp == end_pseudo_hdr)
98*0Sstevel@tonic-gate sp = (uint16_t *)udph;
99*0Sstevel@tonic-gate }
100*0Sstevel@tonic-gate
101*0Sstevel@tonic-gate return (~sum == 0 ? ~0 : ~sum);
102*0Sstevel@tonic-gate }
103