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31 * $KAME: in6_cksum.c,v 1.10 2000/12/03 00:53:59 itojun Exp $
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39 * modification, are permitted provided that the following conditions
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55 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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62 * @(#)in_cksum.c 8.1 (Berkeley) 6/10/93
65 #include <sys/cdefs.h>
66 __FBSDID("$FreeBSD$");
68 #include <sys/param.h>
70 #include <sys/systm.h>
71 #include <netinet/in.h>
72 #include <netinet/ip6.h>
73 #include <netinet6/scope6_var.h>
76 * Checksum routine for Internet Protocol family headers (Portable Version).
78 * This routine is very heavily used in the network
79 * code and should be modified for each CPU to be as fast as possible.
82 #define ADDCARRY(x) (x > 65535 ? x -= 65535 : x)
83 #define REDUCE {l_util.l = sum; sum = l_util.s[0] + l_util.s[1]; (void)ADDCARRY(sum);}
86 _in6_cksum_pseudo(struct ip6_hdr *ip6, uint32_t len, uint8_t nxt, uint16_t csum)
102 * First create IP6 pseudo header and calculate a summary.
104 uph.ph.ph_len = htonl(len);
105 uph.ph.ph_zero[0] = uph.ph.ph_zero[1] = uph.ph.ph_zero[2] = 0;
108 /* Payload length and upper layer identifier. */
109 sum += uph.phs[0]; sum += uph.phs[1];
110 sum += uph.phs[2]; sum += uph.phs[3];
112 /* IPv6 source address. */
113 scope = in6_getscope(&ip6->ip6_src);
114 w = (u_int16_t *)&ip6->ip6_src;
115 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
116 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
120 /* IPv6 destination address. */
121 scope = in6_getscope(&ip6->ip6_dst);
122 w = (u_int16_t *)&ip6->ip6_dst;
123 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
124 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
132 in6_cksum_pseudo(struct ip6_hdr *ip6, uint32_t len, uint8_t nxt, uint16_t csum)
140 sum = _in6_cksum_pseudo(ip6, len, nxt, csum);
146 * m MUST contain a contiguous IP6 header.
147 * off is an offset where TCP/UDP/ICMP6 header starts.
148 * len is a total length of a transport segment.
149 * (e.g. TCP header + TCP payload)
150 * cov is the number of bytes to be taken into account for the checksum
153 in6_cksum_partial(struct mbuf *m, u_int8_t nxt, u_int32_t off,
154 u_int32_t len, u_int32_t cov)
158 int byte_swapped, mlen;
178 KASSERT(m->m_pkthdr.len >= off + len, ("%s: mbuf len (%d) < off(%d)+"
179 "len(%d)", __func__, m->m_pkthdr.len, off, len));
182 * First create IP6 pseudo header and calculate a summary.
184 uph.ph.ph_len = htonl(len);
185 uph.ph.ph_zero[0] = uph.ph.ph_zero[1] = uph.ph.ph_zero[2] = 0;
188 /* Payload length and upper layer identifier. */
189 sum = uph.phs[0]; sum += uph.phs[1];
190 sum += uph.phs[2]; sum += uph.phs[3];
192 ip6 = mtod(m, struct ip6_hdr *);
194 /* IPv6 source address. */
195 scope = in6_getscope(&ip6->ip6_src);
196 w = (u_int16_t *)&ip6->ip6_src;
197 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
198 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
202 /* IPv6 destination address. */
203 scope = in6_getscope(&ip6->ip6_dst);
204 w = (u_int16_t *)&ip6->ip6_dst;
205 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
206 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
211 * Secondly calculate a summary of the first mbuf excluding offset.
220 w = (u_int16_t *)(mtod(m, u_char *) + off);
221 mlen = m->m_len - off;
226 * Force to even boundary.
228 if ((1 & (long)w) && (mlen > 0)) {
231 s_util.c[0] = *(u_char *)w;
232 w = (u_int16_t *)((char *)w + 1);
239 * Unroll the loop to make overhead from
242 while ((mlen -= 32) >= 0) {
243 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
244 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
245 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
246 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
250 while ((mlen -= 8) >= 0) {
251 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
255 if (mlen == 0 && byte_swapped == 0)
258 while ((mlen -= 2) >= 0) {
266 s_util.c[1] = *(char *)w;
271 } else if (mlen == -1)
272 s_util.c[0] = *(char *)w;
277 * Lastly calculate a summary of the rest of mbufs.
280 for (;m && cov; m = m->m_next) {
283 w = mtod(m, u_int16_t *);
286 * The first byte of this mbuf is the continuation
287 * of a word spanning between this mbuf and the
290 * s_util.c[0] is already saved when scanning previous
293 s_util.c[1] = *(char *)w;
295 w = (u_int16_t *)((char *)w + 1);
304 * Force to even boundary.
306 if ((1 & (long) w) && (mlen > 0)) {
309 s_util.c[0] = *(u_char *)w;
310 w = (u_int16_t *)((char *)w + 1);
315 * Unroll the loop to make overhead from
318 while ((mlen -= 32) >= 0) {
319 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
320 sum += w[4]; sum += w[5]; sum += w[6]; sum += w[7];
321 sum += w[8]; sum += w[9]; sum += w[10]; sum += w[11];
322 sum += w[12]; sum += w[13]; sum += w[14]; sum += w[15];
326 while ((mlen -= 8) >= 0) {
327 sum += w[0]; sum += w[1]; sum += w[2]; sum += w[3];
331 if (mlen == 0 && byte_swapped == 0)
334 while ((mlen -= 2) >= 0) {
342 s_util.c[1] = *(char *)w;
347 } else if (mlen == -1)
348 s_util.c[0] = *(char *)w;
351 panic("in6_cksum: out of data");
353 /* The last mbuf has odd # of bytes. Follow the
354 standard (the odd byte may be shifted left by 8 bits
355 or not as determined by endian-ness of the machine) */
360 return (~sum & 0xffff);
364 in6_cksum(struct mbuf *m, u_int8_t nxt, u_int32_t off, u_int32_t len)
366 return (in6_cksum_partial(m, nxt, off, len, len));