/*      $OpenBSD: in4_cksum.c,v 1.8 2022/02/01 15:30:10 miod Exp $      */
/*      $NetBSD: in4_cksum.c,v 1.5 2003/10/13 14:22:20 agc 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 its 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) 2001 Eduardo Horvath.
 * 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 its 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/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/socketvar.h>

#include <netinet/in.h>
#include <netinet/ip.h>
#include <netinet/ip_var.h>

extern int in_cksum_internal(struct mbuf *, int len, int offset, int sum);

int
in4_cksum(struct mbuf *m, u_int8_t nxt, int off, int len)
{
        u_int sum = 0;
        struct ipovly ipov;

        /*
         * Declare three 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.
         */
        u_int tmp1, tmp2;

        if (nxt != 0) {
                /* pseudo header */
                ipov.ih_src = mtod(m, struct ip *)->ip_src;
                ipov.ih_dst = mtod(m, struct ip *)->ip_dst;
                sum = ((u_int)nxt << 16) | htons(len);
                /* assumes sizeof(ipov) == 20 */
                __asm volatile(
                        " lduw [%4 + 12], %1; "
                        " lduw [%4 + 16], %2; "
                        " add %0, %1, %0; "
                        " add %0, %2, %0; "
                        " srlx %0, 32, %2; "
                        " add %0, %2, %0; "
                        : "=r" (sum), "=&r" (tmp1), "=&r" (tmp2)
                        : "0" (sum), "r" (&ipov));
        }

        /* skip unnecessary part */
        while (m && off > 0) {
                if (m->m_len > off)
                        break;
                off -= m->m_len;
                m = m->m_next;
        }
        return (in_cksum_internal(m, len, off, sum));
}