206 lines
6.4 KiB
C
206 lines
6.4 KiB
C
/*
|
|
* Copyright (c) 1982, 1992, 1993
|
|
* The Regents of the University of California. All rights reserved.
|
|
*
|
|
* 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. All advertising materials mentioning features or use of this software
|
|
* must display the following acknowledgement:
|
|
* This product includes software developed by the University of
|
|
* California, Berkeley and its contributors.
|
|
* 4. 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.
|
|
*
|
|
* @(#)ns_cksum.c 8.1 (Berkeley) 6/10/93
|
|
* $Id$
|
|
*/
|
|
|
|
#include <sys/param.h>
|
|
#include <sys/mbuf.h>
|
|
|
|
/*
|
|
* Checksum routine for Network Systems Protocol Packets (Big-Endian).
|
|
*
|
|
* 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) { if ((x) > 65535) (x) -= 65535; }
|
|
#define FOLD(x) {l_util.l = (x); (x) = l_util.s[0] + l_util.s[1]; ADDCARRY(x);}
|
|
|
|
u_short
|
|
ns_cksum(m, len)
|
|
register struct mbuf *m;
|
|
register int len;
|
|
{
|
|
register u_short *w;
|
|
register int sum = 0;
|
|
register int mlen = 0;
|
|
register int sum2;
|
|
|
|
union {
|
|
u_short s[2];
|
|
long l;
|
|
} l_util;
|
|
|
|
for (;m && len; m = m->m_next) {
|
|
if (m->m_len == 0)
|
|
continue;
|
|
/*
|
|
* Each trip around loop adds in
|
|
* word from one mbuf segment.
|
|
*/
|
|
w = mtod(m, u_short *);
|
|
if (mlen == -1) {
|
|
/*
|
|
* There is a byte left from the last segment;
|
|
* ones-complement add it into the checksum.
|
|
*/
|
|
#if BYTE_ORDER == BIG_ENDIAN
|
|
sum += *(u_char *)w;
|
|
#else
|
|
sum += *(u_char *)w << 8;
|
|
#endif
|
|
sum += sum;
|
|
w = (u_short *)(1 + (char *)w);
|
|
mlen = m->m_len - 1;
|
|
len--;
|
|
FOLD(sum);
|
|
} else
|
|
mlen = m->m_len;
|
|
if (len < mlen)
|
|
mlen = len;
|
|
len -= mlen;
|
|
/*
|
|
* We can do a 16 bit ones complement sum using
|
|
* 32 bit arithmetic registers for adding,
|
|
* with carries from the low added
|
|
* into the high (by normal carry-chaining)
|
|
* so long as we fold back before 16 carries have occured.
|
|
*/
|
|
if (1 & (int) w)
|
|
goto uuuuglyy;
|
|
#ifndef TINY
|
|
/* -DTINY reduces the size from 1250 to 550, but slows it down by 22% */
|
|
while ((mlen -= 32) >= 0) {
|
|
sum += w[0]; sum += sum; sum += w[1]; sum += sum;
|
|
sum += w[2]; sum += sum; sum += w[3]; sum += sum;
|
|
sum += w[4]; sum += sum; sum += w[5]; sum += sum;
|
|
sum += w[6]; sum += sum; sum += w[7]; sum += sum;
|
|
FOLD(sum);
|
|
sum += w[8]; sum += sum; sum += w[9]; sum += sum;
|
|
sum += w[10]; sum += sum; sum += w[11]; sum += sum;
|
|
sum += w[12]; sum += sum; sum += w[13]; sum += sum;
|
|
sum += w[14]; sum += sum; sum += w[15]; sum += sum;
|
|
FOLD(sum);
|
|
w += 16;
|
|
}
|
|
mlen += 32;
|
|
#endif
|
|
while ((mlen -= 8) >= 0) {
|
|
sum += w[0]; sum += sum; sum += w[1]; sum += sum;
|
|
sum += w[2]; sum += sum; sum += w[3]; sum += sum;
|
|
FOLD(sum);
|
|
w += 4;
|
|
}
|
|
mlen += 8;
|
|
while ((mlen -= 2) >= 0) {
|
|
sum += *w++; sum += sum;
|
|
}
|
|
goto commoncase;
|
|
uuuuglyy:
|
|
#if BYTE_ORDER == BIG_ENDIAN
|
|
#define ww(n) (((u_char *)w)[n + n + 1])
|
|
#define vv(n) (((u_char *)w)[n + n])
|
|
#else
|
|
#if BYTE_ORDER == LITTLE_ENDIAN
|
|
#define vv(n) (((u_char *)w)[n + n + 1])
|
|
#define ww(n) (((u_char *)w)[n + n])
|
|
#endif
|
|
#endif
|
|
sum2 = 0;
|
|
#ifndef TINY
|
|
while ((mlen -= 32) >= 0) {
|
|
sum += ww(0); sum += sum; sum += ww(1); sum += sum;
|
|
sum += ww(2); sum += sum; sum += ww(3); sum += sum;
|
|
sum += ww(4); sum += sum; sum += ww(5); sum += sum;
|
|
sum += ww(6); sum += sum; sum += ww(7); sum += sum;
|
|
FOLD(sum);
|
|
sum += ww(8); sum += sum; sum += ww(9); sum += sum;
|
|
sum += ww(10); sum += sum; sum += ww(11); sum += sum;
|
|
sum += ww(12); sum += sum; sum += ww(13); sum += sum;
|
|
sum += ww(14); sum += sum; sum += ww(15); sum += sum;
|
|
FOLD(sum);
|
|
sum2 += vv(0); sum2 += sum2; sum2 += vv(1); sum2 += sum2;
|
|
sum2 += vv(2); sum2 += sum2; sum2 += vv(3); sum2 += sum2;
|
|
sum2 += vv(4); sum2 += sum2; sum2 += vv(5); sum2 += sum2;
|
|
sum2 += vv(6); sum2 += sum2; sum2 += vv(7); sum2 += sum2;
|
|
FOLD(sum2);
|
|
sum2 += vv(8); sum2 += sum2; sum2 += vv(9); sum2 += sum2;
|
|
sum2 += vv(10); sum2 += sum2; sum2 += vv(11); sum2 += sum2;
|
|
sum2 += vv(12); sum2 += sum2; sum2 += vv(13); sum2 += sum2;
|
|
sum2 += vv(14); sum2 += sum2; sum2 += vv(15); sum2 += sum2;
|
|
FOLD(sum2);
|
|
w += 16;
|
|
}
|
|
mlen += 32;
|
|
#endif
|
|
while ((mlen -= 8) >= 0) {
|
|
sum += ww(0); sum += sum; sum += ww(1); sum += sum;
|
|
sum += ww(2); sum += sum; sum += ww(3); sum += sum;
|
|
FOLD(sum);
|
|
sum2 += vv(0); sum2 += sum2; sum2 += vv(1); sum2 += sum2;
|
|
sum2 += vv(2); sum2 += sum2; sum2 += vv(3); sum2 += sum2;
|
|
FOLD(sum2);
|
|
w += 4;
|
|
}
|
|
mlen += 8;
|
|
while ((mlen -= 2) >= 0) {
|
|
sum += ww(0); sum += sum;
|
|
sum2 += vv(0); sum2 += sum2;
|
|
w++;
|
|
}
|
|
sum += (sum2 << 8);
|
|
commoncase:
|
|
if (mlen == -1) {
|
|
#if BYTE_ORDER == BIG_ENDIAN
|
|
sum += *(u_char *)w << 8;
|
|
#else
|
|
sum += *(u_char *)w;
|
|
#endif
|
|
}
|
|
FOLD(sum);
|
|
}
|
|
if (mlen == -1) {
|
|
/* We had an odd number of bytes to sum; assume a garbage
|
|
byte of zero and clean up */
|
|
sum += sum;
|
|
FOLD(sum);
|
|
}
|
|
/*
|
|
* sum has already been kept to low sixteen bits.
|
|
* just examine result and exit.
|
|
*/
|
|
if(sum==0xffff) sum = 0;
|
|
return (sum);
|
|
}
|