/*      $NetBSD: dest6.c,v 1.22 2018/04/13 11:01:14 maxv Exp $  */
/*      $KAME: dest6.c,v 1.25 2001/02/22 01:39:16 itojun Exp $  */

/*
* Copyright (C) 1995, 1996, 1997, and 1998 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.
*/

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: dest6.c,v 1.22 2018/04/13 11:01:14 maxv Exp $");

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/errno.h>
#include <sys/time.h>
#include <sys/kernel.h>

#include <net/if.h>

#include <netinet/in.h>
#include <netinet/in_var.h>
#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>
#include <netinet6/ip6_private.h>
#include <netinet/icmp6.h>

/*
* Destination options header processing.
*/
int
dest6_input(struct mbuf **mp, int *offp, int proto)
{
       struct mbuf *m = *mp;
       int off = *offp, erroff, dstoptlen, optlen;
       struct ip6_dest *dstopts;
       u_int8_t *opt;

       /* validation of the length of the header */
       IP6_EXTHDR_GET(dstopts, struct ip6_dest *, m, off, sizeof(*dstopts));
       if (dstopts == NULL)
               return IPPROTO_DONE;
       dstoptlen = (dstopts->ip6d_len + 1) << 3;

       IP6_EXTHDR_GET(dstopts, struct ip6_dest *, m, off, dstoptlen);
       if (dstopts == NULL)
               return IPPROTO_DONE;
       off += dstoptlen;
       dstoptlen -= sizeof(struct ip6_dest);
       opt = (u_int8_t *)dstopts + sizeof(struct ip6_dest);

       /* search header for all options. */
       for (optlen = 0; dstoptlen > 0; dstoptlen -= optlen, opt += optlen) {
               if (*opt != IP6OPT_PAD1 &&
                   (dstoptlen < IP6OPT_MINLEN || *(opt + 1) + 2 > dstoptlen)) {
                       IP6_STATINC(IP6_STAT_TOOSMALL);
                       goto bad;
               }

               switch (*opt) {
               case IP6OPT_PAD1:
                       optlen = 1;
                       break;
               case IP6OPT_PADN:
                       optlen = *(opt + 1) + 2;
                       break;
               default:                /* unknown option */
                       erroff = *offp + (opt - (u_int8_t *)dstopts);
                       optlen = ip6_unknown_opt(opt, m, erroff);
                       if (optlen == -1)
                               return IPPROTO_DONE;
                       optlen += 2;
                       break;
               }
       }

       *offp = off;
       return dstopts->ip6d_nxt;

bad:
       m_freem(m);
       return IPPROTO_DONE;
}