2 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
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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.
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37 * modification, are permitted provided that the following conditions
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40 * notice, this list of conditions and the following disclaimer.
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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)
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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 _in6_cksum_pseudo(struct ip6_hdr *ip6, uint32_t len, uint8_t nxt, uint16_t csum)
100 * First create IP6 pseudo header and calculate a summary.
102 uph.ph.ph_len = htonl(len);
103 uph.ph.ph_zero[0] = uph.ph.ph_zero[1] = uph.ph.ph_zero[2] = 0;
106 /* Payload length and upper layer identifier. */
107 sum += uph.phs[0]; sum += uph.phs[1];
108 sum += uph.phs[2]; sum += uph.phs[3];
110 /* IPv6 source address. */
111 scope = in6_getscope(&ip6->ip6_src);
112 w = (u_int16_t *)&ip6->ip6_src;
113 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
114 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
118 /* IPv6 destination address. */
119 scope = in6_getscope(&ip6->ip6_dst);
120 w = (u_int16_t *)&ip6->ip6_dst;
121 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
122 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
130 in6_cksum_pseudo(struct ip6_hdr *ip6, uint32_t len, uint8_t nxt, uint16_t csum)
138 sum = _in6_cksum_pseudo(ip6, len, nxt, csum);
144 * m MUST contain a contiguous IP6 header.
145 * off is an offset where TCP/UDP/ICMP6 header starts.
146 * len is a total length of a transport segment.
147 * (e.g. TCP header + TCP payload)
150 in6_cksum(struct mbuf *m, u_int8_t nxt, u_int32_t off, u_int32_t len)
154 int byte_swapped, mlen;
174 KASSERT(m->m_pkthdr.len >= off + len, ("%s: mbuf len (%d) < off(%d)+"
175 "len(%d)", __func__, m->m_pkthdr.len, off, len));
178 * First create IP6 pseudo header and calculate a summary.
180 uph.ph.ph_len = htonl(len);
181 uph.ph.ph_zero[0] = uph.ph.ph_zero[1] = uph.ph.ph_zero[2] = 0;
184 /* Payload length and upper layer identifier. */
185 sum = uph.phs[0]; sum += uph.phs[1];
186 sum += uph.phs[2]; sum += uph.phs[3];
188 ip6 = mtod(m, struct ip6_hdr *);
190 /* IPv6 source address. */
191 scope = in6_getscope(&ip6->ip6_src);
192 w = (u_int16_t *)&ip6->ip6_src;
193 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
194 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
198 /* IPv6 destination address. */
199 scope = in6_getscope(&ip6->ip6_dst);
200 w = (u_int16_t *)&ip6->ip6_dst;
201 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
202 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
207 * Secondly calculate a summary of the first mbuf excluding offset.
216 w = (u_int16_t *)(mtod(m, u_char *) + off);
217 mlen = m->m_len - off;
222 * Force to even boundary.
224 if ((1 & (long)w) && (mlen > 0)) {
227 s_util.c[0] = *(u_char *)w;
228 w = (u_int16_t *)((char *)w + 1);
235 * Unroll the loop to make overhead from
238 while ((mlen -= 32) >= 0) {
239 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
240 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
241 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
242 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
246 while ((mlen -= 8) >= 0) {
247 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
251 if (mlen == 0 && byte_swapped == 0)
254 while ((mlen -= 2) >= 0) {
262 s_util.c[1] = *(char *)w;
267 } else if (mlen == -1)
268 s_util.c[0] = *(char *)w;
273 * Lastly calculate a summary of the rest of mbufs.
276 for (;m && len; m = m->m_next) {
279 w = mtod(m, u_int16_t *);
282 * The first byte of this mbuf is the continuation
283 * of a word spanning between this mbuf and the
286 * s_util.c[0] is already saved when scanning previous
289 s_util.c[1] = *(char *)w;
291 w = (u_int16_t *)((char *)w + 1);
300 * Force to even boundary.
302 if ((1 & (long) w) && (mlen > 0)) {
305 s_util.c[0] = *(u_char *)w;
306 w = (u_int16_t *)((char *)w + 1);
311 * Unroll the loop to make overhead from
314 while ((mlen -= 32) >= 0) {
315 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
316 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
317 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
318 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
322 while ((mlen -= 8) >= 0) {
323 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
327 if (mlen == 0 && byte_swapped == 0)
330 while ((mlen -= 2) >= 0) {
338 s_util.c[1] = *(char *)w;
343 } else if (mlen == -1)
344 s_util.c[0] = *(char *)w;
347 panic("in6_cksum: out of data");
349 /* The last mbuf has odd # of bytes. Follow the
350 standard (the odd byte may be shifted left by 8 bits
351 or not as determined by endian-ness of the machine) */
356 return (~sum & 0xffff);