source: rtems-libbsd/freebsd/i386/include/freebsd/machine/in_cksum.h @ 6434b4b

/*-
 * Copyright (c) 1990 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.
 * 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.
 *
 *      from tahoe:     in_cksum.c      1.2     86/01/05
 *      from:           @(#)in_cksum.c  1.3 (Berkeley) 1/19/91
 *      from: Id: in_cksum.c,v 1.8 1995/12/03 18:35:19 bde Exp
 * $FreeBSD$
 */

#ifndef _MACHINE_IN_CKSUM_HH_
#define _MACHINE_IN_CKSUM_HH_   1

#ifndef _SYS_CDEFS_HH_
#error this file needs sys/cdefs.h as a prerequisite
#endif

/*
 * MP safe (alfred)
 */

#include <freebsd/sys/cdefs.h>

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

/*
 * It it useful to have an Internet checksum routine which is inlineable
 * and optimized specifically for the task of computing IP header checksums
 * in the normal case (where there are no options and the header length is
 * therefore always exactly five 32-bit words.
 */
#if defined(__GNUCLIKE_ASM) && !defined(__INTEL_COMPILER)
static __inline u_int
in_cksum_hdr(const struct ip *ip)
{
        u_int sum = 0;

        __asm(
                "addl %1, %0\n"
                "adcl %2, %0\n"
                "adcl %3, %0\n"
                "adcl %4, %0\n"
                "adcl %5, %0\n"
                "adcl $0, %0"
                : "+r" (sum)
                : "g" (((const u_int32_t *)ip)[0]),
                  "g" (((const u_int32_t *)ip)[1]),
                  "g" (((const u_int32_t *)ip)[2]),
                  "g" (((const u_int32_t *)ip)[3]),
                  "g" (((const u_int32_t *)ip)[4])
                : "cc"
        );
        sum = (sum & 0xffff) + (sum >> 16);
        if (sum > 0xffff)
                sum -= 0xffff;

        return ~sum & 0xffff;
}

static __inline void
in_cksum_update(struct ip *ip)
{
        int __tmpsum;
        __tmpsum = (int)ntohs(ip->ip_sum) + 256;
        ip->ip_sum = htons(__tmpsum + (__tmpsum >> 16));
}

static __inline u_short
in_addword(u_short sum, u_short b)
{
        __asm(
                "addw %1, %0\n"
                "adcw $0, %0"
                : "+r" (sum)
                : "g" (b)
                : "cc"
        );
        return (sum);
}

static __inline u_short
in_pseudo(u_int sum, u_int b, u_int c)
{
        __asm(
                "addl %1, %0\n"
                "adcl %2, %0\n"
                "adcl $0, %0"
                : "+r" (sum)
                : "g" (b),
                  "g" (c)
                : "cc"
        );
        sum = (sum & 0xffff) + (sum >> 16);
        if (sum > 0xffff)
                sum -= 0xffff;
        return (sum);
}

#else
#define in_cksum_update(ip) \
        do { \
                int __tmpsum; \
                __tmpsum = (int)ntohs(ip->ip_sum) + 256; \
                ip->ip_sum = htons(__tmpsum + (__tmpsum >> 16)); \
        } while(0)

#endif

#ifdef _KERNEL
#if !defined(__GNUCLIKE_ASM) || defined(__INTEL_COMPILER)
u_int in_cksum_hdr(const struct ip *ip);
u_short in_addword(u_short sum, u_short b);
u_short in_pseudo(u_int sum, u_int b, u_int c);
#endif
u_short in_cksum_skip(struct mbuf *m, int len, int skip);
#endif /* _KERNEL */

#endif /* _MACHINE_IN_CKSUM_HH_ */