2 * Copyright (c) 1988, 1992, 1993
3 * The Regents of the University of California. All rights reserved.
5 * Matt Thomas <matt@3am-software.com>
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8 * modification, are permitted provided that the following conditions
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17 * This product includes software developed by the University of
18 * California, Berkeley and its contributors.
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35 * @(#)in_cksum.c 8.1 (Berkeley) 6/10/93
38 #include <sys/cdefs.h>
39 __FBSDID("$FreeBSD$");
41 #include <sys/param.h>
43 #include <sys/systm.h>
44 #include <netinet/in_systm.h>
45 #include <netinet/in.h>
46 #include <netinet/ip.h>
47 #include <machine/in_cksum.h>
50 * Checksum routine for Internet Protocol family headers
51 * (Portable Alpha version).
53 * This routine is very heavily used in the network
54 * code and should be modified for each CPU to be as fast as possible.
57 #define ADDCARRY(x) (x > 65535 ? x -= 65535 : x)
61 sum = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \
66 l_util.l = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \
67 sum = l_util.s[0] + l_util.s[1]; \
71 static const u_int32_t in_masks[] = {
72 #if _BYTE_ORDER == _LITTLE_ENDIAN
73 /*0 bytes*/ /*1 byte*/ /*2 bytes*/ /*3 bytes*/
74 0x00000000, 0x000000FF, 0x0000FFFF, 0x00FFFFFF, /* offset 0 */
75 0x00000000, 0x0000FF00, 0x00FFFF00, 0xFFFFFF00, /* offset 1 */
76 0x00000000, 0x00FF0000, 0xFFFF0000, 0xFFFF0000, /* offset 2 */
77 0x00000000, 0xFF000000, 0xFF000000, 0xFF000000, /* offset 3 */
79 /*0 bytes*/ /*1 byte*/ /*2 bytes*/ /*3 bytes*/
80 0x00000000, 0xFF000000, 0xFFFF0000, 0xFFFFFF00, /* offset 0 */
81 0x00000000, 0x00FF0000, 0x00FFFF00, 0x00FFFFFF, /* offset 1 */
82 0x00000000, 0x0000FF00, 0x0000FFFF, 0x0000FFFF, /* offset 2 */
83 0x00000000, 0x000000FF, 0x000000FF, 0x000000FF, /* offset 3 */
98 in_cksumdata(const void *buf, int len)
100 const u_int32_t *lw = (const u_int32_t *) buf;
106 if ((3 & (long) lw) == 0 && len == 20) {
107 sum = (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3] + lw[4];
112 if ((offset = 3 & (long) lw) != 0) {
113 const u_int32_t *masks = in_masks + (offset << 2);
114 lw = (u_int32_t *) (((long) lw) - offset);
115 sum = *lw++ & masks[len >= 3 ? 3 : len];
124 * Force to cache line boundary.
126 offset = 32 - (0x1f & (long) lw);
127 if (offset < 32 && len > offset) {
130 sum += (u_int64_t) lw[0];
134 sum += (u_int64_t) lw[0] + lw[1];
138 sum += (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3];
144 * access prefilling to start load of next cache line.
145 * then add current cache line
146 * save result of prefilling for loop iteration.
149 while ((len -= 32) >= 4) {
150 u_int64_t prefilling = lw[8];
151 sum += prefilled + lw[1] + lw[2] + lw[3]
152 + lw[4] + lw[5] + lw[6] + lw[7];
154 prefilled = prefilling;
157 sum += prefilled + lw[1] + lw[2] + lw[3]
158 + lw[4] + lw[5] + lw[6] + lw[7];
163 while ((len -= 16) >= 0) {
164 sum += (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3];
168 while ((len -= 4) >= 0) {
169 sum += (u_int64_t) *lw++;
173 sum += (u_int64_t) (in_masks[len] & *lw);
179 in_addword(u_short a, u_short b)
181 u_int64_t sum = a + b;
188 in_pseudo(u_int32_t a, u_int32_t b, u_int32_t c)
194 sum = (u_int64_t) a + b + c;
200 in_cksum_skip(struct mbuf *m, int len, int skip)
210 for (; skip && m; m = m->m_next) {
211 if (m->m_len > skip) {
212 mlen = m->m_len - skip;
213 addr = mtod(m, caddr_t) + skip;
220 for (; m && len; m = m->m_next) {
224 addr = mtod(m, caddr_t);
229 if ((clen ^ (uintptr_t) addr) & 1)
230 sum += in_cksumdata(addr, mlen) << 8;
232 sum += in_cksumdata(addr, mlen);
238 return (~sum & 0xffff);
241 u_int in_cksum_hdr(const struct ip *ip)
243 u_int64_t sum = in_cksumdata(ip, sizeof(struct ip));
247 return (~sum & 0xffff);