2 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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12 * documentation and/or other materials provided with the distribution.
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25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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29 * $KAME: in6_cksum.c,v 1.10 2000/12/03 00:53:59 itojun Exp $
33 * Copyright (c) 1988, 1992, 1993
34 * The Regents of the University of California. All rights reserved.
36 * Redistribution and use in source and binary forms, with or without
37 * modification, are permitted provided that the following conditions
39 * 1. Redistributions of source code must retain the above copyright
40 * notice, this list of conditions and the following disclaimer.
41 * 2. Redistributions in binary form must reproduce the above copyright
42 * notice, this list of conditions and the following disclaimer in the
43 * documentation and/or other materials provided with the distribution.
44 * 4. Neither the name of the University nor the names of its contributors
45 * may be used to endorse or promote products derived from this software
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49 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
50 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
51 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
52 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
53 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
54 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
55 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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60 * @(#)in_cksum.c 8.1 (Berkeley) 6/10/93
63 #include <sys/cdefs.h>
64 __FBSDID("$FreeBSD$");
66 #include <sys/param.h>
68 #include <sys/systm.h>
69 #include <netinet/in.h>
70 #include <netinet/ip6.h>
71 #include <netinet6/scope6_var.h>
74 * Checksum routine for Internet Protocol family headers (Portable Version).
76 * This routine is very heavily used in the network
77 * code and should be modified for each CPU to be as fast as possible.
80 #define ADDCARRY(x) (x > 65535 ? x -= 65535 : x)
81 #define REDUCE {l_util.l = sum; sum = l_util.s[0] + l_util.s[1]; (void)ADDCARRY(sum);}
84 * m MUST contain a contiguous IP6 header.
85 * off is an offset where TCP/UDP/ICMP6 header starts.
86 * len is a total length of a transport segment.
87 * (e.g. TCP header + TCP payload)
90 in6_cksum(struct mbuf *m, u_int8_t nxt, u_int32_t off, u_int32_t len)
94 int byte_swapped, mlen;
114 KASSERT(m->m_pkthdr.len >= off + len, ("%s: mbuf len (%d) < off(%d)+"
115 "len(%d)", __func__, m->m_pkthdr.len, off, len));
118 * First create IP6 pseudo header and calculate a summary.
120 uph.ph.ph_len = htonl(len);
121 uph.ph.ph_zero[0] = uph.ph.ph_zero[1] = uph.ph.ph_zero[2] = 0;
124 /* Payload length and upper layer identifier. */
125 sum = uph.phs[0]; sum += uph.phs[1];
126 sum += uph.phs[2]; sum += uph.phs[3];
128 ip6 = mtod(m, struct ip6_hdr *);
130 /* IPv6 source address. */
131 scope = in6_getscope(&ip6->ip6_src);
132 w = (u_int16_t *)&ip6->ip6_src;
133 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
134 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
138 /* IPv6 destination address. */
139 scope = in6_getscope(&ip6->ip6_dst);
140 w = (u_int16_t *)&ip6->ip6_dst;
141 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
142 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
147 * Secondly calculate a summary of the first mbuf excluding offset.
156 w = (u_int16_t *)(mtod(m, u_char *) + off);
157 mlen = m->m_len - off;
162 * Force to even boundary.
164 if ((1 & (long)w) && (mlen > 0)) {
167 s_util.c[0] = *(u_char *)w;
168 w = (u_int16_t *)((char *)w + 1);
175 * Unroll the loop to make overhead from
178 while ((mlen -= 32) >= 0) {
179 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
180 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
181 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
182 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
186 while ((mlen -= 8) >= 0) {
187 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
191 if (mlen == 0 && byte_swapped == 0)
194 while ((mlen -= 2) >= 0) {
202 s_util.c[1] = *(char *)w;
207 } else if (mlen == -1)
208 s_util.c[0] = *(char *)w;
213 * Lastly calculate a summary of the rest of mbufs.
216 for (;m && len; m = m->m_next) {
219 w = mtod(m, u_int16_t *);
222 * The first byte of this mbuf is the continuation
223 * of a word spanning between this mbuf and the
226 * s_util.c[0] is already saved when scanning previous
229 s_util.c[1] = *(char *)w;
231 w = (u_int16_t *)((char *)w + 1);
240 * Force to even boundary.
242 if ((1 & (long) w) && (mlen > 0)) {
245 s_util.c[0] = *(u_char *)w;
246 w = (u_int16_t *)((char *)w + 1);
251 * Unroll the loop to make overhead from
254 while ((mlen -= 32) >= 0) {
255 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
256 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
257 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
258 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
262 while ((mlen -= 8) >= 0) {
263 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
267 if (mlen == 0 && byte_swapped == 0)
270 while ((mlen -= 2) >= 0) {
278 s_util.c[1] = *(char *)w;
283 } else if (mlen == -1)
284 s_util.c[0] = *(char *)w;
287 panic("in6_cksum: out of data");
289 /* The last mbuf has odd # of bytes. Follow the
290 standard (the odd byte may be shifted left by 8 bits
291 or not as determined by endian-ness of the machine) */
296 return (~sum & 0xffff);