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/* $OpenBSD: ip6opt.c,v 1.9 2017/04/27 23:52:35 millert Exp $ */ |
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/* $KAME: ip6opt.c,v 1.18 2005/06/15 07:11:35 keiichi Exp $ */ |
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/* |
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* Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project. |
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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 project 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 PROJECT 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 PROJECT 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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#include <sys/types.h> |
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#include <sys/socket.h> |
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#include <netinet/in.h> |
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#include <netinet/ip6.h> |
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#include <string.h> |
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#include <stdio.h> |
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static int ip6optlen(u_int8_t *opt, u_int8_t *lim); |
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/* |
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* Calculate the length of a given IPv6 option. Also checks |
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* if the option is safely stored in user's buffer according to the |
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* calculated length and the limitation of the buffer. |
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*/ |
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static int |
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ip6optlen(u_int8_t *opt, u_int8_t *lim) |
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{ |
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int optlen; |
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if (*opt == IP6OPT_PAD1) |
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optlen = 1; |
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else { |
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/* is there enough space to store type and len? */ |
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if (opt + 2 > lim) |
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return (0); |
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optlen = *(opt + 1) + 2; |
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} |
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if (opt + optlen <= lim) |
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return (optlen); |
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return (0); |
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} |
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/* |
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* The following functions are defined in RFC3542, which is a successor |
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* of RFC2292. |
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*/ |
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int |
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inet6_opt_init(void *extbuf, socklen_t extlen) |
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{ |
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struct ip6_ext *ext = (struct ip6_ext *)extbuf; |
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if (ext) { |
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if (extlen <= 0 || (extlen % 8)) |
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return (-1); |
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ext->ip6e_len = (extlen >> 3) - 1; |
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} |
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return (2); /* sizeof the next and the length fields */ |
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} |
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int |
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inet6_opt_append(void *extbuf, socklen_t extlen, int offset, u_int8_t type, |
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socklen_t len, u_int8_t align, void **databufp) |
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{ |
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int currentlen = offset, padlen = 0; |
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/* |
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* The option type must have a value from 2 to 255, inclusive. |
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* (0 and 1 are reserved for the Pad1 and PadN options, respectively.) |
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*/ |
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#if 0 /* always false */ |
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if (type < 2 || type > 255) |
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#else |
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if (type < 2) |
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#endif |
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return (-1); |
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/* |
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* The option data length must have a value between 0 and 255, |
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* inclusive, and is the length of the option data that follows. |
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*/ |
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if (len > 255) |
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return (-1); |
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/* |
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* The align parameter must have a value of 1, 2, 4, or 8. |
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* The align value can not exceed the value of len. |
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*/ |
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if (align != 1 && align != 2 && align != 4 && align != 8) |
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return (-1); |
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if (align > len) |
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return (-1); |
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/* Calculate the padding length. */ |
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currentlen += 2 + len; /* 2 means "type + len" */ |
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if (currentlen % align) |
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padlen = align - (currentlen % align); |
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/* The option must fit in the extension header buffer. */ |
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currentlen += padlen; |
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if (extlen && /* XXX: right? */ |
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currentlen > extlen) |
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return (-1); |
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if (extbuf) { |
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u_int8_t *optp = (u_int8_t *)extbuf + offset; |
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if (padlen == 1) { |
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/* insert a Pad1 option */ |
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*optp = IP6OPT_PAD1; |
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optp++; |
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} else if (padlen > 0) { |
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/* insert a PadN option for alignment */ |
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*optp++ = IP6OPT_PADN; |
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*optp++ = padlen - 2; |
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memset(optp, 0, padlen - 2); |
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optp += (padlen - 2); |
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} |
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*optp++ = type; |
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*optp++ = len; |
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*databufp = optp; |
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} |
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return (currentlen); |
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} |
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int |
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inet6_opt_finish(void *extbuf, socklen_t extlen, int offset) |
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{ |
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int updatelen = offset > 0 ? (1 + ((offset - 1) | 7)) : 0;; |
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if (extbuf) { |
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u_int8_t *padp; |
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int padlen = updatelen - offset; |
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if (updatelen > extlen) |
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return (-1); |
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padp = (u_int8_t *)extbuf + offset; |
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if (padlen == 1) |
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*padp = IP6OPT_PAD1; |
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else if (padlen > 0) { |
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*padp++ = IP6OPT_PADN; |
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*padp++ = (padlen - 2); |
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memset(padp, 0, padlen - 2); |
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} |
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} |
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return (updatelen); |
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} |
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int |
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inet6_opt_set_val(void *databuf, int offset, void *val, socklen_t vallen) |
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{ |
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memcpy((u_int8_t *)databuf + offset, val, vallen); |
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return (offset + vallen); |
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} |
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int |
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inet6_opt_next(void *extbuf, socklen_t extlen, int offset, u_int8_t *typep, |
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socklen_t *lenp, void **databufp) |
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{ |
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u_int8_t *optp, *lim; |
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int optlen; |
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/* Validate extlen. XXX: is the variable really necessary?? */ |
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if (extlen == 0 || (extlen % 8)) |
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return (-1); |
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lim = (u_int8_t *)extbuf + extlen; |
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/* |
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* If this is the first time this function called for this options |
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* header, simply return the 1st option. |
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* Otherwise, search the option list for the next option. |
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*/ |
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if (offset == 0) |
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optp = (u_int8_t *)((struct ip6_hbh *)extbuf + 1); |
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else |
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optp = (u_int8_t *)extbuf + offset; |
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/* Find the next option skipping any padding options. */ |
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while (optp < lim) { |
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switch(*optp) { |
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case IP6OPT_PAD1: |
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optp++; |
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break; |
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case IP6OPT_PADN: |
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if ((optlen = ip6optlen(optp, lim)) == 0) |
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goto optend; |
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optp += optlen; |
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break; |
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default: /* found */ |
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if ((optlen = ip6optlen(optp, lim)) == 0) |
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goto optend; |
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*typep = *optp; |
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*lenp = optlen - 2; |
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*databufp = optp + 2; |
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return (optp + optlen - (u_int8_t *)extbuf); |
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} |
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} |
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optend: |
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*databufp = NULL; /* for safety */ |
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return (-1); |
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} |
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int |
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inet6_opt_find(void *extbuf, socklen_t extlen, int offset, u_int8_t type, |
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socklen_t *lenp, void **databufp) |
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{ |
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u_int8_t *optp, *lim; |
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int optlen; |
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/* Validate extlen. XXX: is the variable really necessary?? */ |
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if (extlen == 0 || (extlen % 8)) |
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return (-1); |
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lim = (u_int8_t *)extbuf + extlen; |
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/* |
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* If this is the first time this function called for this options |
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* header, simply return the 1st option. |
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* Otherwise, search the option list for the next option. |
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*/ |
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if (offset == 0) |
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optp = (u_int8_t *)((struct ip6_hbh *)extbuf + 1); |
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else |
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optp = (u_int8_t *)extbuf + offset; |
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/* Find the specified option */ |
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while (optp < lim) { |
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if ((optlen = ip6optlen(optp, lim)) == 0) |
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goto optend; |
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if (*optp == type) { /* found */ |
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*lenp = optlen - 2; |
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*databufp = optp + 2; |
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return (optp + optlen - (u_int8_t *)extbuf); |
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} |
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optp += optlen; |
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} |
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optend: |
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*databufp = NULL; /* for safety */ |
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return (-1); |
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} |
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int |
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inet6_opt_get_val(void *databuf, int offset, void *val, socklen_t vallen) |
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{ |
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/* we can't assume alignment here */ |
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memcpy(val, (u_int8_t *)databuf + offset, vallen); |
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return (offset + vallen); |
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} |