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freebsd
GitHub Repository: freebsd/freebsd-src
 Path: blob/main/sys/i386/include/in_cksum.h
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/*-

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 * SPDX-License-Identifier: BSD-3-Clause

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 *

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 * Copyright (c) 1990 The Regents of the University of California.

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 * All rights reserved.

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 *

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 * Redistribution and use in source and binary forms, with or without

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 * modification, are permitted provided that the following conditions

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 * are met:

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 * 1. Redistributions of source code must retain the above copyright

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 *    notice, this list of conditions and the following disclaimer.

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 * 2. Redistributions in binary form must reproduce the above copyright

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 *    notice, this list of conditions and the following disclaimer in the

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 *    documentation and/or other materials provided with the distribution.

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 * 3. Neither the name of the University nor the names of its contributors

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 *    may be used to endorse or promote products derived from this software

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 *    without specific prior written permission.

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 *

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 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND

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 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

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 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

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 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE

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 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

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 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

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 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

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 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

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 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

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 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

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 * SUCH DAMAGE.

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 *

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 *	from tahoe:	in_cksum.c	1.2	86/01/05

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 *	from: Id: in_cksum.c,v 1.8 1995/12/03 18:35:19 bde Exp

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 */

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#ifndef _MACHINE_IN_CKSUM_H_

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#define	_MACHINE_IN_CKSUM_H_	1

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#include <sys/cdefs.h>

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#define in_cksum(m, len)	in_cksum_skip(m, len, 0)

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/*

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 * It it useful to have an Internet checksum routine which is inlineable

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 * and optimized specifically for the task of computing IP header checksums

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 * in the normal case (where there are no options and the header length is

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 * therefore always exactly five 32-bit words.

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 */

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#if defined(IPVERSION) && (IPVERSION == 4)

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static __inline u_int

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in_cksum_hdr(const struct ip *ip)

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{

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	u_int sum = 0;

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	__asm(

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		"addl %1, %0\n"

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		"adcl %2, %0\n"

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		"adcl %3, %0\n"

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		"adcl %4, %0\n"

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		"adcl %5, %0\n"

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		"adcl $0, %0"

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		: "+r" (sum)

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		: "g" (((const u_int32_t *)ip)[0]),

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		  "g" (((const u_int32_t *)ip)[1]),

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		  "g" (((const u_int32_t *)ip)[2]),

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		  "g" (((const u_int32_t *)ip)[3]),

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		  "g" (((const u_int32_t *)ip)[4])

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		: "cc"

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	);

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	sum = (sum & 0xffff) + (sum >> 16);

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	if (sum > 0xffff)

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		sum -= 0xffff;

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	return ~sum & 0xffff;

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}

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#endif

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static __inline u_short

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in_addword(u_short sum, u_short b)

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{

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	__asm(

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		"addw %1, %0\n"

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		"adcw $0, %0"

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		: "+r" (sum)

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		: "g" (b)

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		: "cc"

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	);

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	return (sum);

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}

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static __inline u_short

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in_pseudo(u_int sum, u_int b, u_int c)

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{

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	__asm(

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		"addl %1, %0\n"

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		"adcl %2, %0\n"

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		"adcl $0, %0"

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		: "+r" (sum)

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		: "g" (b),

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		  "g" (c)

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		: "cc"

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	);

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	sum = (sum & 0xffff) + (sum >> 16);

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	if (sum > 0xffff)

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		sum -= 0xffff;

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	return (sum);

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}

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#ifdef _KERNEL

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#define	HAVE_MD_IN_CKSUM

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u_short in_cksum_skip(struct mbuf *m, int len, int skip);

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#endif /* _KERNEL */

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#endif /* _MACHINE_IN_CKSUM_H_ */

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