mirror of
https://git.FreeBSD.org/src.git
synced 2024-12-15 10:17:20 +00:00
115 lines
3.1 KiB
C
115 lines
3.1 KiB
C
/*
|
|
* Copyright (c) 1995, Mike Mitchell
|
|
* 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.
|
|
*
|
|
* @(#)ipx_cksum.c
|
|
*/
|
|
|
|
#include <sys/cdefs.h>
|
|
__FBSDID("$FreeBSD$");
|
|
|
|
#include <sys/param.h>
|
|
#include <sys/mbuf.h>
|
|
#include <sys/libkern.h>
|
|
|
|
#include <netipx/ipx.h>
|
|
#include <netipx/ipx_var.h>
|
|
|
|
|
|
#define SUMADV sum += *w++
|
|
|
|
u_short
|
|
ipx_cksum(struct mbuf *m, int len) {
|
|
u_int32_t sum = 0;
|
|
u_char *w;
|
|
u_char oldtc;
|
|
int mlen, words;
|
|
struct ipx *ipx;
|
|
union {
|
|
u_char b[2];
|
|
u_short w;
|
|
} buf;
|
|
|
|
ipx = mtod(m, struct ipx*);
|
|
oldtc = ipx->ipx_tc;
|
|
ipx->ipx_tc = 0;
|
|
w = (u_char *)&ipx->ipx_len;
|
|
len -= 2;
|
|
mlen = 2;
|
|
|
|
for(;;) {
|
|
mlen = imin(m->m_len - mlen, len);
|
|
words = mlen / 2;
|
|
len -= mlen & ~1;
|
|
while (words >= 16) {
|
|
SUMADV; SUMADV; SUMADV; SUMADV;
|
|
SUMADV; SUMADV; SUMADV; SUMADV;
|
|
SUMADV; SUMADV; SUMADV; SUMADV;
|
|
SUMADV; SUMADV; SUMADV; SUMADV;
|
|
words -= 16;
|
|
}
|
|
while (words--)
|
|
SUMADV;
|
|
if (len == 0)
|
|
break;
|
|
mlen &= 1;
|
|
if (mlen) {
|
|
buf.b[0] = *w;
|
|
if (--len == 0) {
|
|
buf.b[1] = 0;
|
|
sum += buf.w;
|
|
break;
|
|
}
|
|
}
|
|
m = m->m_next;
|
|
if (m == NULL)
|
|
break;
|
|
w = mtod(m, u_char *);
|
|
if (mlen) {
|
|
buf.b[1] = *w;
|
|
sum += buf.w;
|
|
w++;
|
|
if (--len == 0)
|
|
break;
|
|
}
|
|
}
|
|
|
|
ipx->ipx_tc = oldtc;
|
|
|
|
sum = (sum & 0xffff) + (sum >> 16);
|
|
if (sum >= 0x10000)
|
|
sum++;
|
|
if (sum)
|
|
sum = ~sum;
|
|
return (sum);
|
|
}
|