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/* $OpenBSD: in_cksum.c,v 1.6 2003/06/02 23:27:43 millert Exp $ */
/* $NetBSD: in_cksum.c,v 1.4 1996/11/13 21:13:06 cgd Exp $ */
/*
* Copyright (c) 1988, 1992, 1993
* The Regents of the University of California. All rights reserved.
* Copyright (c) 1996
* Matt Thomas <matt@3am-software.com>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)in_cksum.c 8.1 (Berkeley) 6/10/93
*/
#include <sys/param.h>
#include <sys/mbuf.h>
#include <sys/systm.h>
#include <netinet/in.h>
u_int64_t in_cksumdata(caddr_t, int);
/*
* Checksum routine for Internet Protocol family headers
* (Portable Alpha version).
*
* This routine is very heavily used in the network
* code and should be modified for each CPU to be as fast as possible.
*/
#define ADDCARRY(x) (x > 65535 ? x -= 65535 : x)
#define REDUCE32 \
{ \
q_util.q = sum; \
sum = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \
}
#define REDUCE16 \
{ \
q_util.q = sum; \
l_util.l = q_util.s[0] + q_util.s[1] + q_util.s[2] + q_util.s[3]; \
sum = l_util.s[0] + l_util.s[1]; \
ADDCARRY(sum); \
}
static const u_int32_t in_masks[] = {
/*0 bytes*/ /*1 byte*/ /*2 bytes*/ /*3 bytes*/
0x00000000, 0x000000FF, 0x0000FFFF, 0x00FFFFFF, /* offset 0 */
0x00000000, 0x0000FF00, 0x00FFFF00, 0xFFFFFF00, /* offset 1 */
0x00000000, 0x00FF0000, 0xFFFF0000, 0xFFFF0000, /* offset 2 */
0x00000000, 0xFF000000, 0xFF000000, 0xFF000000, /* offset 3 */
};
union l_util {
u_int16_t s[2];
u_int32_t l;
};
union q_util {
u_int16_t s[4];
u_int32_t l[2];
u_int64_t q;
};
u_int64_t in_cksumdata(caddr_t buf, int len);
u_int64_t
in_cksumdata(buf, len)
register caddr_t buf;
register int len;
{
const u_int32_t *lw = (u_int32_t *) buf;
u_int64_t sum = 0;
u_int64_t prefilled;
int offset;
union q_util q_util;
if ((3 & (long) lw) == 0 && len == 20) {
sum = (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3] + lw[4];
REDUCE32;
return sum;
}
if ((offset = 3 & (long) lw) != 0) {
const u_int32_t *masks = in_masks + (offset << 2);
lw = (u_int32_t *) (((long) lw) - offset);
sum = *lw++ & masks[len >= 3 ? 3 : len];
len -= 4 - offset;
if (len <= 0) {
REDUCE32;
return sum;
}
}
#if 0
/*
* Force to cache line boundary.
*/
offset = 32 - (0x1f & (long) lw);
if (offset < 32 && len > offset) {
len -= offset;
if (4 & offset) {
sum += (u_int64_t) lw[0];
lw += 1;
}
if (8 & offset) {
sum += (u_int64_t) lw[0] + lw[1];
lw += 2;
}
if (16 & offset) {
sum += (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3];
lw += 4;
}
}
#endif
/*
* access prefilling to start load of next cache line.
* then add current cache line
* save result of prefilling for loop iteration.
*/
prefilled = lw[0];
while ((len -= 32) >= 4) {
u_int64_t prefilling = lw[8];
sum += prefilled + lw[1] + lw[2] + lw[3]
+ lw[4] + lw[5] + lw[6] + lw[7];
lw += 8;
prefilled = prefilling;
}
if (len >= 0) {
sum += prefilled + lw[1] + lw[2] + lw[3]
+ lw[4] + lw[5] + lw[6] + lw[7];
lw += 8;
} else {
len += 32;
}
while ((len -= 16) >= 0) {
sum += (u_int64_t) lw[0] + lw[1] + lw[2] + lw[3];
lw += 4;
}
len += 16;
while ((len -= 4) >= 0) {
sum += (u_int64_t) *lw++;
}
len += 4;
if (len > 0)
sum += (u_int64_t) (in_masks[len] & *lw);
REDUCE32;
return sum;
}
int
in_cksum(m, len)
register struct mbuf *m;
register int len;
{
register u_int64_t sum = 0;
register int mlen = 0;
register int clen = 0;
register caddr_t addr;
union l_util l_util;
union q_util q_util;
for (; m && len; m = m->m_next) {
if (m->m_len == 0)
continue;
mlen = m->m_len;
if (len < mlen)
mlen = len;
addr = mtod(m, caddr_t);
if ((clen ^ (long) addr) & 1)
sum += in_cksumdata(addr, mlen) << 8;
else
sum += in_cksumdata(addr, mlen);
clen += mlen;
len -= mlen;
}
REDUCE16;
return (~sum & 0xffff);
}
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