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347 lines
10 KiB
C
347 lines
10 KiB
C
/* Copyright (C) 2003 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Ulrich Drepper <drepper@redhat.com>, 2003.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
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02111-1307 USA. */
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#include <assert.h>
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#include <string.h>
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#include <netinet/in.h>
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#include <netinet/ip6.h>
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#include <sys/param.h>
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#include <sys/socket.h>
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#include "libc-symbols.h"
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#define roundup(x, y) ((((x)+((y)-1))/(y))*(y))
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static void
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internal_function
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add_pad (struct cmsghdr *cmsg, int len)
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{
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unsigned char *p = CMSG_DATA (cmsg) + cmsg->cmsg_len - CMSG_LEN (0);
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if (len == 1)
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/* Special handling for 1, a one-byte solution. */
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*p++ = IP6OPT_PAD1;
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else if (len != 0)
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{
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/* Multibyte padding. */
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*p++ = IP6OPT_PADN;
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*p++ = len - 2; /* Discount the two header bytes. */
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/* The rest is filled with zero. */
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memset (p, '\0', len - 2);
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p += len - 2;
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}
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/* Account for the bytes. */
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cmsg->cmsg_len += len;
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}
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static int
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get_opt_end (const uint8_t **result, const uint8_t *startp,
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const uint8_t *endp)
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{
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if (startp >= endp)
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/* Out of bounds. */
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return -1;
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if (*startp == IP6OPT_PAD1)
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{
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/* Just this one byte. */
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*result = startp + 1;
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return 0;
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}
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/* Now we know there must be at least two bytes. */
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if (startp + 2 > endp
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/* Now we can get the length byte. */
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|| startp + startp[1] + 2 > endp)
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return -1;
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*result = startp + startp[1] + 2;
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return 0;
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}
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/* RFC 2292, 6.3.1
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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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int
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inet6_option_space (nbytes)
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int nbytes;
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{
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/* Add room for the extension header. */
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nbytes += sizeof (struct ip6_ext);
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return CMSG_SPACE (roundup (nbytes, 8));
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}
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/* RFC 2292, 6.3.2
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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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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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/* Only Hop-by-Hop or Destination options allowed. */
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if (type != IPV6_HOPOPTS && type != IPV6_DSTOPTS)
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return -1;
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/* BP is a pointer to the previously allocated space. */
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struct cmsghdr *newp = (struct cmsghdr *) bp;
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/* Initialize the message header.
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Length: No data yet, only the cmsghdr struct. */
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newp->cmsg_len = CMSG_LEN (0);
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/* Originating protocol: obviously IPv6. */
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newp->cmsg_level = IPPROTO_IPV6;
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/* Message type. */
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newp->cmsg_type = type;
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/* Pass up the result. */
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*cmsgp = newp;
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return 0;
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}
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/* RFC 2292, 6.3.3
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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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int
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inet6_option_append (cmsg, typep, multx, plusy)
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struct cmsghdr *cmsg;
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const uint8_t *typep;
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int multx;
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int plusy;
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{
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/* typep is a pointer to the 8-bit option type. It is assumed that this
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field is immediately followed by the 8-bit option data length field,
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which is then followed immediately by the option data.
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The option types IP6OPT_PAD1 and IP6OPT_PADN also must be handled. */
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int len = typep[0] == IP6OPT_PAD1 ? 1 : typep[1] + 2;
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/* Get the pointer to the space in the message. */
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uint8_t *ptr = inet6_option_alloc (cmsg, len, multx, plusy);
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if (ptr == NULL)
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/* Some problem with the parameters. */
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return -1;
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/* Copy the content. */
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memcpy (ptr, typep, len);
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return 0;
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}
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/* RFC 2292, 6.3.4
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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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uint8_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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/* The RFC limits the value of the alignment values. */
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if ((multx != 1 && multx != 2 && multx != 4 && multx != 8)
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|| ! (plusy >= 0 && plusy <= 7))
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return NULL;
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/* Current data size. */
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int dsize = cmsg->cmsg_len - CMSG_LEN (0);
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/* The first two bytes of the option are for the extended header. */
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if (__builtin_expect (dsize == 0, 0))
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{
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cmsg->cmsg_len += sizeof (struct ip6_ext);
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dsize = sizeof (struct ip6_ext);
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}
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/* First add padding. */
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add_pad (cmsg, ((multx - (dsize & (multx - 1))) & (multx - 1)) + plusy);
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/* Return the pointer to the start of the option space. */
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uint8_t *result = CMSG_DATA (cmsg) + cmsg->cmsg_len - CMSG_LEN (0);
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cmsg->cmsg_len += datalen;
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/* The extended option header length is measured in 8-byte groups.
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To represent the current length we might have to add padding. */
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dsize = cmsg->cmsg_len - CMSG_LEN (0);
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add_pad (cmsg, (8 - (dsize & (8 - 1))) & (8 - 1));
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/* Record the new length of the option. */
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assert (((cmsg->cmsg_len - CMSG_LEN (0)) % 8) == 0);
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int len8b = (cmsg->cmsg_len - CMSG_LEN (0)) / 8 - 1;
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if (len8b >= 256)
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/* Too long. */
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return NULL;
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((struct ip6_ext *) CMSG_DATA (cmsg))->ip6e_len = len8b;
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return result;
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}
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libc_hidden_def (inet6_option_alloc)
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/* RFC 2292, 6.3.5
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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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int
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inet6_option_next (cmsg, tptrp)
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const struct cmsghdr *cmsg;
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uint8_t **tptrp;
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{
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/* Make sure it is an option of the right type. */
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if (cmsg->cmsg_level != IPPROTO_IPV6
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|| (cmsg->cmsg_type != IPV6_HOPOPTS && cmsg->cmsg_type != IPV6_DSTOPTS))
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return -1;
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/* Pointer to the extension header. We only compute the address, we
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don't access anything yet. */
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const struct ip6_ext *ip6e = (const struct ip6_ext *) CMSG_DATA (cmsg);
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/* Make sure the message is long enough. */
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if (cmsg->cmsg_len < CMSG_LEN (sizeof (struct ip6_ext))
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/* Now we can access the extension header. */
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|| cmsg->cmsg_len < CMSG_LEN ((ip6e->ip6e_len + 1) * 8))
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/* Too small. */
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return -1;
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/* Determine the address of the byte past the message. */
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const uint8_t *endp = CMSG_DATA (cmsg) + (ip6e->ip6e_len + 1) * 8;
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const uint8_t *result;
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if (tptrp == NULL)
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/* This is the first call, return the first option if there is one. */
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result = (const uint8_t *) (ip6e + 1);
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else
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{
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/* Make sure *TPTRP points to a beginning of a new option in
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the message. The upper limit is checked in get_opt_end. */
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if (*tptrp < (const uint8_t *) (ip6e + 1))
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return -1;
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/* Get the beginning of the next option. */
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if (get_opt_end (&result, *tptrp, endp) != 0)
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return -1;
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}
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/* We know where the next option starts. */
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*tptrp = (uint8_t *) result;
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/* Check the option is fully represented in the message. */
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return get_opt_end (&result, result, endp);
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}
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/* RFC 2292, 6.3.6
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This function is similar to the previously described
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inet6_option_next() function, except this function lets the caller
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specify the option type to be searched for, instead of always
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returning the next option in the ancillary data object. cmsg is a
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pointer to cmsghdr structure of which cmsg_level equals IPPROTO_IPV6
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and cmsg_type equals either IPV6_HOPOPTS or IPV6_DSTOPTS. */
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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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uint8_t **tptrp;
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int type;
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{
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/* Make sure it is an option of the right type. */
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if (cmsg->cmsg_level != IPPROTO_IPV6
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|| (cmsg->cmsg_type != IPV6_HOPOPTS && cmsg->cmsg_type != IPV6_DSTOPTS))
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return -1;
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/* Pointer to the extension header. We only compute the address, we
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don't access anything yet. */
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const struct ip6_ext *ip6e = (const struct ip6_ext *) CMSG_DATA (cmsg);
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/* Make sure the message is long enough. */
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if (cmsg->cmsg_len < CMSG_LEN (sizeof (struct ip6_ext))
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/* Now we can access the extension header. */
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|| cmsg->cmsg_len < CMSG_LEN ((ip6e->ip6e_len + 1) * 8))
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/* Too small. */
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return -1;
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/* Determine the address of the byte past the message. */
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const uint8_t *endp = CMSG_DATA (cmsg) + (ip6e->ip6e_len + 1) * 8;
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const uint8_t *next;
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if (tptrp == NULL)
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/* This is the first call, return the first option if there is one. */
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next = (const uint8_t *) (ip6e + 1);
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else
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{
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/* Make sure *TPTRP points to a beginning of a new option in
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the message. The upper limit is checked in get_opt_end. */
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if (*tptrp < (const uint8_t *) (ip6e + 1))
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return -1;
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/* Get the beginning of the next option. */
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if (get_opt_end (&next, *tptrp, endp) != 0)
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return -1;
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}
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/* Now search for the appropriate typed entry. */
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const uint8_t *result;
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do
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{
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result = next;
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/* Get the end of this entry. */
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if (get_opt_end (&next, result, endp) != 0)
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return -1;
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}
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while (*result != type);
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/* We know where the next option starts. */
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*tptrp = (uint8_t *) result;
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/* Success. */
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return 0;
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}
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