/*

 * Copyright (c) 2020 Apple Inc. All rights reserved.

 *

 * @APPLE_OSREFERENCE_LICENSE_HEADER_START@

 *

 * This file contains Original Code and/or Modifications of Original Code

 * as defined in and that are subject to the Apple Public Source License

 * Version 2.0 (the 'License'). You may not use this file except in

 * compliance with the License. The rights granted to you under the License

 * may not be used to create, or enable the creation or redistribution of,

 * unlawful or unlicensed copies of an Apple operating system, or to

 * circumvent, violate, or enable the circumvention or violation of, any

 * terms of an Apple operating system software license agreement.

 *

 * Please obtain a copy of the License at

 * http://www.opensource.apple.com/apsl/ and read it before using this file.

 *

 * The Original Code and all software distributed under the License are

 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER

 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,

 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,

 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.

 * Please see the License for the specific language governing rights and

 * limitations under the License.

 *

 * @APPLE_OSREFERENCE_LICENSE_HEADER_END@

 */

/*  $FreeBSD: src/sys/netinet6/dest6.c,v 1.1.2.3 2001/07/03 11:01:49 ume Exp $  */

/*  $KAME: dest6.c,v 1.27 2001/03/29 05:34:30 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/param.h>

#include <sys/systm.h>

#include <sys/malloc.h>

#include <sys/mbuf.h>

#include <sys/domain.h>

#include <sys/protosw.h>

#include <sys/socket.h>

#include <sys/errno.h>

#include <sys/time.h>

#include <sys/kernel.h>

#include <net/if.h>

#include <net/route.h>

#include <netinet/in.h>

#include <netinet/in_var.h>

#include <netinet/ip6.h>

#include <netinet6/ip6_var.h>

#include <netinet/icmp6.h>

/*

 * Destination options header processing.

 */

int

dest6_input(struct mbuf **mp, int *offp, int proto)

{

#pragma unused(proto)

  struct mbuf *m = *mp;

  int off = *offp, dstoptlen = 0, optlen = 0;

  struct ip6_dest *dstopts = NULL;

  u_int8_t *opt = NULL;

  /* validation of the length of the header */

  IP6_EXTHDR_CHECK(m, off, sizeof(*dstopts), return IPPROTO_DONE);

  dstopts = (struct ip6_dest *)(mtod(m, caddr_t) + off);

  dstoptlen = (dstopts->ip6d_len + 1) << 3;

  IP6_EXTHDR_CHECK(m, off, dstoptlen, return IPPROTO_DONE);

  dstopts = (struct ip6_dest *)(mtod(m, caddr_t) + off);

  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)) {

      ip6stat.ip6s_toosmall++;

      goto bad;

    }

    switch (*opt) {

    case IP6OPT_PAD1:

      optlen = 1;

      break;

    case IP6OPT_PADN:

      optlen = *(opt + 1) + 2;

      break;

    default:                /* unknown option */

      optlen = ip6_unknown_opt(opt, m,

          opt - mtod(m, u_int8_t *));

      if (optlen == -1) {

        return IPPROTO_DONE;

      }

      optlen += 2;

      break;

    }

  }

  *mp = m;

  *offp = off;

  return dstopts->ip6d_nxt;

bad:

  *mp = NULL;

  m_freem(m);

  return IPPROTO_DONE;

}