386 lines
10 KiB
C
386 lines
10 KiB
C
/*
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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/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <sys/param.h>
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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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static void inet6_insert_padopt(u_char *p, int len);
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/*
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* This function returns the number of bytes required to hold an option
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* when it is stored as ancillary data, including the cmsghdr structure
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* at the beginning, and any padding at the end (to make its size a
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* multiple of 8 bytes). The argument is the size of the structure
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* defining the option, which must include any pad bytes at the
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* beginning (the value y in the alignment term "xn + y"), the type
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* byte, the length byte, and the option data.
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*/
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int
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inet6_option_space(nbytes)
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int nbytes;
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{
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nbytes += 2; /* we need space for nxt-hdr and length fields */
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return(CMSG_SPACE((nbytes + 7) & ~7));
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}
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/*
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* This function is called once per ancillary data object that will
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* contain either Hop-by-Hop or Destination options. It returns 0 on
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* success or -1 on an error.
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*/
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int
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inet6_option_init(bp, cmsgp, type)
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void *bp;
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struct cmsghdr **cmsgp;
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int type;
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{
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struct cmsghdr *ch = (struct cmsghdr *)bp;
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/* argument validation */
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if (type != IPV6_HOPOPTS && type != IPV6_DSTOPTS)
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return(-1);
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ch->cmsg_level = IPPROTO_IPV6;
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ch->cmsg_type = type;
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ch->cmsg_len = CMSG_LEN(0);
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*cmsgp = ch;
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return(0);
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}
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/*
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* This function appends a Hop-by-Hop option or a Destination option
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* into an ancillary data object that has been initialized by
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* inet6_option_init(). This function returns 0 if it succeeds or -1 on
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* an error.
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* multx is the value x in the alignment term "xn + y" described
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* earlier. It must have a value of 1, 2, 4, or 8.
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* plusy is the value y in the alignment term "xn + y" described
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* earlier. It must have a value between 0 and 7, inclusive.
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*/
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int
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inet6_option_append(cmsg, typep, multx, plusy)
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struct cmsghdr *cmsg;
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const u_int8_t *typep;
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int multx;
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int plusy;
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{
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int padlen, optlen, off;
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u_char *bp = (u_char *)cmsg + cmsg->cmsg_len;
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struct ip6_ext *eh = (struct ip6_ext *)CMSG_DATA(cmsg);
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/* argument validation */
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if (multx != 1 && multx != 2 && multx != 4 && multx != 8)
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return(-1);
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if (plusy < 0 || plusy > 7)
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return(-1);
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/*
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* If this is the first option, allocate space for the
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* first 2 bytes(for next header and length fields) of
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* the option header.
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*/
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if (bp == (u_char *)eh) {
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bp += 2;
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cmsg->cmsg_len += 2;
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}
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/* calculate pad length before the option. */
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off = bp - (u_char *)eh;
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padlen = (((off % multx) + (multx - 1)) & ~(multx - 1)) -
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(off % multx);
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padlen += plusy;
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/* insert padding */
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inet6_insert_padopt(bp, padlen);
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cmsg->cmsg_len += padlen;
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bp += padlen;
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/* copy the option */
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if (typep[0] == IP6OPT_PAD1)
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optlen = 1;
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else
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optlen = typep[1] + 2;
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memcpy(bp, typep, optlen);
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bp += optlen;
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cmsg->cmsg_len += optlen;
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/* calculate pad length after the option and insert the padding */
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off = bp - (u_char *)eh;
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padlen = ((off + 7) & ~7) - off;
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inet6_insert_padopt(bp, padlen);
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bp += padlen;
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cmsg->cmsg_len += padlen;
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/* update the length field of the ip6 option header */
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eh->ip6e_len = ((bp - (u_char *)eh) >> 3) - 1;
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return(0);
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}
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/*
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* This function appends a Hop-by-Hop option or a Destination option
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* into an ancillary data object that has been initialized by
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* inet6_option_init(). This function returns a pointer to the 8-bit
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* option type field that starts the option on success, or NULL on an
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* error.
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* The difference between this function and inet6_option_append() is
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* that the latter copies the contents of a previously built option into
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* the ancillary data object while the current function returns a
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* pointer to the space in the data object where the option's TLV must
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* then be built by the caller.
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*
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*/
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u_int8_t *
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inet6_option_alloc(cmsg, datalen, multx, plusy)
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struct cmsghdr *cmsg;
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int datalen;
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int multx;
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int plusy;
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{
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int padlen, off;
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u_int8_t *bp = (u_char *)cmsg + cmsg->cmsg_len;
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u_int8_t *retval;
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struct ip6_ext *eh = (struct ip6_ext *)CMSG_DATA(cmsg);
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/* argument validation */
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if (multx != 1 && multx != 2 && multx != 4 && multx != 8)
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return(NULL);
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if (plusy < 0 || plusy > 7)
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return(NULL);
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/*
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* If this is the first option, allocate space for the
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* first 2 bytes(for next header and length fields) of
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* the option header.
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*/
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if (bp == (u_char *)eh) {
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bp += 2;
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cmsg->cmsg_len += 2;
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}
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/* calculate pad length before the option. */
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off = bp - (u_char *)eh;
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padlen = (((off % multx) + (multx - 1)) & ~(multx - 1)) -
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(off % multx);
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padlen += plusy;
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/* insert padding */
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inet6_insert_padopt(bp, padlen);
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cmsg->cmsg_len += padlen;
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bp += padlen;
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/* keep space to store specified length of data */
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retval = bp;
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bp += datalen;
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cmsg->cmsg_len += datalen;
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/* calculate pad length after the option and insert the padding */
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off = bp - (u_char *)eh;
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padlen = ((off + 7) & ~7) - off;
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inet6_insert_padopt(bp, padlen);
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bp += padlen;
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cmsg->cmsg_len += padlen;
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/* update the length field of the ip6 option header */
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eh->ip6e_len = ((bp - (u_char *)eh) >> 3) - 1;
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return(retval);
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}
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/*
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* This function processes the next Hop-by-Hop option or Destination
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* option in an ancillary data object. If another option remains to be
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* processed, the return value of the function is 0 and *tptrp points to
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* the 8-bit option type field (which is followed by the 8-bit option
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* data length, followed by the option data). If no more options remain
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* to be processed, the return value is -1 and *tptrp is NULL. If an
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* error occurs, the return value is -1 and *tptrp is not NULL.
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* (RFC 2292, 6.3.5)
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*/
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int
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inet6_option_next(cmsg, tptrp)
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const struct cmsghdr *cmsg;
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u_int8_t **tptrp;
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{
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struct ip6_ext *ip6e;
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int hdrlen, optlen;
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u_int8_t *lim;
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if (cmsg->cmsg_level != IPPROTO_IPV6 ||
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(cmsg->cmsg_type != IPV6_HOPOPTS &&
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cmsg->cmsg_type != IPV6_DSTOPTS))
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return(-1);
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/* message length validation */
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if (cmsg->cmsg_len < CMSG_SPACE(sizeof(struct ip6_ext)))
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return(-1);
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ip6e = (struct ip6_ext *)CMSG_DATA(cmsg);
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hdrlen = (ip6e->ip6e_len + 1) << 3;
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if (cmsg->cmsg_len < CMSG_SPACE(hdrlen))
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return(-1);
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/*
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* If the caller does not specify the starting point,
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* 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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lim = (u_int8_t *)ip6e + hdrlen;
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if (*tptrp == NULL)
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*tptrp = (u_int8_t *)(ip6e + 1);
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else {
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if ((optlen = ip6optlen(*tptrp, lim)) == 0)
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return(-1);
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*tptrp = *tptrp + optlen;
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}
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if (*tptrp >= lim) { /* there is no option */
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*tptrp = NULL;
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return(-1);
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}
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/*
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* Finally, checks if the next option is safely stored in the
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* cmsg data.
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*/
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if (ip6optlen(*tptrp, lim) == 0)
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return(-1);
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else
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return(0);
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}
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/*
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* This function is similar to the inet6_option_next() function,
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* except this function lets the caller specify the option type to be
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* searched for, instead of always returning the next option in the
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* ancillary data object.
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* Note: RFC 2292 says the type of tptrp is u_int8_t *, but we think
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* it's a typo. The variable should be type of u_int8_t **.
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*/
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int
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inet6_option_find(cmsg, tptrp, type)
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const struct cmsghdr *cmsg;
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u_int8_t **tptrp;
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int type;
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{
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struct ip6_ext *ip6e;
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int hdrlen, optlen;
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u_int8_t *optp, *lim;
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if (cmsg->cmsg_level != IPPROTO_IPV6 ||
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(cmsg->cmsg_type != IPV6_HOPOPTS &&
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cmsg->cmsg_type != IPV6_DSTOPTS))
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return(-1);
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/* message length validation */
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if (cmsg->cmsg_len < CMSG_SPACE(sizeof(struct ip6_ext)))
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return(-1);
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ip6e = (struct ip6_ext *)CMSG_DATA(cmsg);
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hdrlen = (ip6e->ip6e_len + 1) << 3;
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if (cmsg->cmsg_len < CMSG_SPACE(hdrlen))
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return(-1);
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/*
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* If the caller does not specify the starting point,
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* search from the beginning of the option list.
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* Otherwise, search from *the next option* of the specified point.
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*/
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lim = (u_int8_t *)ip6e + hdrlen;
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if (*tptrp == NULL)
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*tptrp = (u_int8_t *)(ip6e + 1);
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else {
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if ((optlen = ip6optlen(*tptrp, lim)) == 0)
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return(-1);
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*tptrp = *tptrp + optlen;
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}
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for (optp = *tptrp; optp < lim; optp += optlen) {
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if (*optp == type) {
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*tptrp = optp;
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return(0);
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}
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if ((optlen = ip6optlen(optp, lim)) == 0)
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return(-1);
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}
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/* search failed */
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*tptrp = NULL;
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return(-1);
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}
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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(opt, lim)
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u_int8_t *opt, *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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static void
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inet6_insert_padopt(u_char *p, int len)
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{
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switch(len) {
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case 0:
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return;
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case 1:
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p[0] = IP6OPT_PAD1;
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return;
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default:
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p[0] = IP6OPT_PADN;
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p[1] = len - 2;
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memset(&p[2], 0, len - 2);
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return;
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}
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}
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