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/* $NetBSD: in_cksum.c,v 1.12.10.4 2005/12/11 10:28:36 christos Exp $ */
/*
* Copyright (c) 1995 Matthew R. Green.
* Copyright (c) 1992, 1993
* The Regents of the University of California. All rights reserved.
*
* 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, and it's contributors.
*
* 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) 6/11/93
*/
/*
* Copyright (c) 1995 Zubin Dittia.
* Copyright (c) 1994, 1998 Charles M. Hannum.
*
* 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, and it's contributors.
*
* 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.
*
* @(#)in_cksum.c 8.1 (Berkeley) 6/11/93
*/
#include <sys/cdefs.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <netinet/in.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>
/*
* Checksum routine for Internet Protocol family headers.
*
* This routine is very heavily used in the network
* code and should be modified for each CPU to be as fast as possible.
*
* SPARC version.
*/
/*
* The checksum computation code here is significantly faster than its
* vanilla C counterpart (by significantly, I mean 2-3 times faster if
* the data is in cache, and 1.5-2 times faster if the data is not in
* cache).
* We optimize on three fronts:
* 1. By using the add-with-carry (addxcc) instruction, we can use
* 32-bit operations instead of 16-bit operations.
* 2. By unrolling the main loop to reduce branch overheads.
* 3. By doing a sequence of load,load,add,add,load,load,add,add,
* we can avoid the extra stall cycle which is incurred if the
* instruction immediately following a load tries to use the
* target register of the load.
* Another possible optimization is to replace a pair of 32-bit loads
* with a single 64-bit load (ldd) instruction, but I found that although
* this improves performance somewhat on Sun4c machines, it actually
* reduces performance considerably on Sun4m machines (I don't know why).
* So I chose to leave it out.
*
* Zubin Dittia (zubin@dworkin.wustl.edu)
*/
#define Asm __asm __volatile
#define ADD64 Asm(" ld [%4+ 0],%1; ld [%4+ 4],%2; \
addcc %0,%1,%0; addxcc %0,%2,%0; \
ld [%4+ 8],%1; ld [%4+12],%2; \
addxcc %0,%1,%0; addxcc %0,%2,%0; \
ld [%4+16],%1; ld [%4+20],%2; \
addxcc %0,%1,%0; addxcc %0,%2,%0; \
ld [%4+24],%1; ld [%4+28],%2; \
addxcc %0,%1,%0; addxcc %0,%2,%0; \
ld [%4+32],%1; ld [%4+36],%2; \
addxcc %0,%1,%0; addxcc %0,%2,%0; \
ld [%4+40],%1; ld [%4+44],%2; \
addxcc %0,%1,%0; addxcc %0,%2,%0; \
ld [%4+48],%1; ld [%4+52],%2; \
addxcc %0,%1,%0; addxcc %0,%2,%0; \
ld [%4+56],%1; ld [%4+60],%2; \
addxcc %0,%1,%0; addxcc %0,%2,%0; \
addxcc %0,0,%0" \
: "=r" (sum), "=&r" (tmp1), "=&r" (tmp2)\
: "0" (sum), "r" (w))
#define ADD32 Asm(" ld [%4+ 0],%1; ld [%4+ 4],%2; \
addcc %0,%1,%0; addxcc %0,%2,%0; \
ld [%4+ 8],%1; ld [%4+12],%2; \
addxcc %0,%1,%0; addxcc %0,%2,%0; \
ld [%4+16],%1; ld [%4+20],%2; \
addxcc %0,%1,%0; addxcc %0,%2,%0; \
ld [%4+24],%1; ld [%4+28],%2; \
addxcc %0,%1,%0; addxcc %0,%2,%0; \
addxcc %0,0,%0" \
: "=r" (sum), "=&r" (tmp1), "=&r" (tmp2)\
: "0" (sum), "r" (w))
#define ADD16 Asm(" ld [%4+ 0],%1; ld [%4+ 4],%2; \
addcc %0,%1,%0; addxcc %0,%2,%0; \
ld [%4+ 8],%1; ld [%4+12],%2; \
addxcc %0,%1,%0; addxcc %0,%2,%0; \
addxcc %0,0,%0" \
: "=r" (sum), "=&r" (tmp1), "=&r" (tmp2)\
: "0" (sum), "r" (w))
#define ADD8 Asm(" ld [%4+ 0],%1; ld [%4+ 4],%2; \
addcc %0,%1,%0; addxcc %0,%2,%0; \
addxcc %0,0,%0" \
: "=r" (sum), "=&r" (tmp1), "=&r" (tmp2)\
: "0" (sum), "r" (w))
#define ADD4 Asm(" ld [%3+ 0],%1; \
addcc %0,%1,%0; \
addxcc %0,0,%0" \
: "=r" (sum), "=&r" (tmp1) \
: "0" (sum), "r" (w))
#define REDUCE {sum = (sum & 0xffff) + (sum >> 16);}
#define ADDCARRY {if (sum > 0xffff) sum -= 0xffff;}
#define ROL {sum = sum << 8;} /* depends on recent REDUCE */
#define ADDBYTE {ROL; sum += *w; byte_swapped ^= 1;}
#define ADDSHORT {sum += *(u_short *)w;}
#define ADVANCE(n) {w += n; mlen -= n;}
static __inline__ int
in_cksum_internal(struct mbuf *m, int off, int len, u_int sum)
{
u_char *w;
int mlen = 0;
int byte_swapped = 0;
/*
* Declare two temporary registers for use by the asm code. We
* allow the compiler to pick which specific machine registers to
* use, instead of hard-coding this in the asm code above.
*/
u_int tmp1, tmp2;
for (; m && len; m = m->m_next) {
if (m->m_len == 0)
continue;
w = mtod(m, u_char *) + off;
mlen = m->m_len - off;
off = 0;
if (len < mlen)
mlen = len;
len -= mlen;
/*
* Ensure that we're aligned on a word boundary here so
* that we can do 32 bit operations below.
*/
if ((3 & (long)w) != 0) {
REDUCE;
if ((1 & (long)w) != 0 && mlen >= 1) {
ADDBYTE;
ADVANCE(1);
}
if ((2 & (long)w) != 0 && mlen >= 2) {
ADDSHORT;
ADVANCE(2);
}
}
/*
* Do as many 32 bit operations as possible using the
* 64/32/16/8/4 macro's above, using as many as possible of
* these.
*/
while (mlen >= 64) {
ADD64;
ADVANCE(64);
}
if (mlen >= 32) {
ADD32;
ADVANCE(32);
}
if (mlen >= 16) {
ADD16;
ADVANCE(16);
}
if (mlen >= 8) {
ADD8;
ADVANCE(8);
}
if (mlen >= 4) {
ADD4;
ADVANCE(4)
}
if (mlen == 0)
continue;
REDUCE;
if (mlen >= 2) {
ADDSHORT;
ADVANCE(2);
}
if (mlen == 1) {
ADDBYTE;
}
}
if (byte_swapped) {
REDUCE;
ROL;
}
REDUCE;
ADDCARRY;
return (0xffff ^ sum);
}
int
in_cksum(struct mbuf *m, int len)
{
return (in_cksum_internal(m, 0, len, 0));
}
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