NetBSD-5.0.2/sys/arch/vax/vax/in4_cksum.c
/* $NetBSD: in4_cksum.c,v 1.12 2008/03/11 05:34:03 matt Exp $ */
/*
* Copyright (C) 1999 WIDE Project.
* 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. Neither the name of the project 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 PROJECT 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 PROJECT 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.
*/
/*
* Copyright (c) 1988, 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. 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/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: in4_cksum.c,v 1.12 2008/03/11 05:34:03 matt Exp $");
#include <sys/param.h>
#include <sys/mbuf.h>
#include <sys/systm.h>
#include <sys/socket.h>
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#ifdef CKSUMDEBUG
int in4_cksum_md_debug(struct mbuf *m, uint8_t nxt, int off, int len);
#define in4_cksum in4_cksum_md_debug
#include <netinet/in4_cksum.c>
#undef in4_cksum
#undef ADDCARRY
#undef REDUCE
#endif
/*
* Checksum routine for Internet Protocol family headers.
* This is only for IPv4 pseudo header checksum.
* No need to clear non-pseudo-header fields in IPv4 header.
* len is for actual payload size, and does not include IPv4 header and
* skipped header chain (off + len should be equal to the whole packet).
*
* This implementation is VAX version.
*/
#define REDUCE {sum = (sum & 0xffff) + (sum >> 16);}
#define ADDCARRY {if (sum > 0xffff) sum -= 0xffff;}
#define ADVANCE(n) {w += n; mlen -= n;}
#define SWAP {sum <<= 8;} /* depends on recent REDUCE */
#define Asm __asm volatile
#define ADDL Asm("addl2 (%0)+,%1": "=r" (w), "=r" (sum): "0" (w), "1" (sum))
#define ADWC Asm("adwc (%0)+,%1": "=r" (w), "=r" (sum): "0" (w), "1" (sum))
#define ADDC Asm("adwc $0,%0" : "=r" (sum) : "0" (sum))
#define UNSWAP Asm("rotl $8,%0,%0" : "=r" (sum) : "0" (sum))
#define ADDBYTE {sum += *w; SWAP; byte_swapped ^= 1;}
#define ADDWORD {sum += *(uint16_t *)w;}
int
in4_cksum(struct mbuf *m, uint8_t nxt, int off, int len)
{
uint8_t *w;
uint32_t sum = 0;
int mlen = 0;
int byte_swapped = 0;
#ifdef CKSUMDEBUG
int debugrv = in4_cksum_md_debug(m, nxt, off, len);
#endif
if (nxt != 0) {
#ifdef DIAGNOSTIC
if (off < sizeof(struct ipovly))
panic("in4_cksum: offset too short");
if (m->m_len < sizeof(struct ip))
panic("in4_cksum: bad mbuf chain");
#endif
__asm volatile(
"movzwl 16(%%ap),%0;" /* mov len to sum */
"addb2 8(%%ap),%0;" /* add proto to sum */
"rotl $8,%0,%0;" /* htons, carry is preserved */
"adwc 12(%2),%0;" /* add src ip */
"adwc 16(%2),%0;" /* add dst ip */
"adwc $0,%0;" /* clean up carry */
: "=r" (sum)
: "0" (sum), "r" (mtod(m, void *)));
}
/* skip unnecessary part */
while (m && off > 0) {
if (m->m_len > off)
break;
off -= m->m_len;
m = m->m_next;
}
for (;m && len; m = m->m_next) {
if ((mlen = m->m_len) == 0)
continue;
w = mtod(m, uint8_t *);
if (off) {
w += off;
mlen -= off;
off = 0;
}
if (len < mlen)
mlen = len;
len -= mlen;
if (mlen < 16)
goto short_mbuf;
/*
* Ensure that we're aligned on a word boundary here so
* that we can do 32 bit operations below.
*/
if ((3 & (intptr_t) w) != 0) {
REDUCE;
if ((1 & (intptr_t) w) != 0) {
ADDBYTE;
ADVANCE(1);
}
if ((2 & (intptr_t) w) != 0) {
ADDWORD;
ADVANCE(2);
}
}
/*
* Do as much of the checksum as possible 32 bits at at time.
* In fact, this loop is unrolled to make overhead from
* branches &c small.
*/
while ((mlen -= 32) >= 0) {
/*
* Add with carry 16 words and fold in the last carry
* by adding a 0 with carry.
*/
ADDL; ADWC; ADWC; ADWC;
ADWC; ADWC; ADWC; ADWC;
ADDC;
}
mlen += 32;
if (mlen >= 16) {
ADDL; ADWC; ADWC; ADWC;
ADDC;
mlen -= 16;
}
short_mbuf:
if (mlen >= 8) {
ADDL; ADWC;
ADDC;
mlen -= 8;
}
if (mlen >= 4) {
ADDL;
ADDC;
mlen -= 4;
}
if (mlen > 0) {
REDUCE;
if (mlen >= 2) {
ADDWORD;
ADVANCE(2);
}
if (mlen >= 1) {
ADDBYTE;
}
}
}
if (len)
printf("cksum4: out of data\n");
if (byte_swapped) {
UNSWAP;
}
REDUCE;
ADDCARRY;
#ifdef CKSUMDEBUG
if ((sum ^ 0xffff) != debugrv)
printf("in4_cksum: rv != debugrv (rv %x debugrv %x)\n",
(sum ^ 0xffff), debugrv);
#endif
return (sum ^ 0xffff);
}