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-rw-r--r--inet/inet6_opt.c278
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diff --git a/inet/inet6_opt.c b/inet/inet6_opt.c
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+/* Copyright (C) 2006, 2007 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Ulrich Drepper <drepper@redhat.com>, 2006.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+#include <string.h>
+#include <netinet/in.h>
+#include <netinet/ip6.h>
+
+
+/* RFC 3542, 10.1
+
+ This function returns the number of bytes needed for the empty
+ extension header i.e., without any options. If EXTBUF is not NULL it
+ also initializes the extension header to have the correct length
+ field. In that case if the EXTLEN value is not a positive (i.e.,
+ non-zero) multiple of 8 the function fails and returns -1. */
+int
+inet6_opt_init (void *extbuf, socklen_t extlen)
+{
+ if (extbuf != NULL)
+ {
+ if (extlen <= 0 || (extlen % 8) != 0)
+ return -1;
+
+ /* Fill in the length in units of 8 octets. */
+ struct ip6_hbh *extp = (struct ip6_hbh *) extbuf;
+ extp->ip6h_len = extlen / 8;
+ }
+
+ return sizeof (struct ip6_hbh);
+}
+
+
+static void
+add_padding (uint8_t *extbuf, int offset, int npad)
+{
+ if (npad == 1)
+ extbuf[offset] = IP6OPT_PAD1;
+ else if (npad > 0)
+ {
+ struct ip6_opt *pad_opt = (struct ip6_opt *) (extbuf + offset);
+
+ pad_opt->ip6o_type = IP6OPT_PADN;
+ pad_opt->ip6o_len = npad - sizeof (struct ip6_opt);
+ /* Clear the memory used by the padding. */
+ memset (pad_opt + 1, '\0', pad_opt->ip6o_len);
+ }
+}
+
+
+
+/* RFC 3542, 10.2
+
+ This function returns the updated total length taking into account
+ adding an option with length 'len' and alignment 'align'. If
+ EXTBUF is not NULL then, in addition to returning the length, the
+ function inserts any needed pad option, initializes the option
+ (setting the type and length fields) and returns a pointer to the
+ location for the option content in databufp. If the option does
+ not fit in the extension header buffer the function returns -1. */
+int
+inet6_opt_append (void *extbuf, socklen_t extlen, int offset, uint8_t type,
+ socklen_t len, uint8_t align, void **databufp)
+{
+ /* Check minimum offset. */
+ if (offset < sizeof (struct ip6_hbh))
+ return -1;
+
+ /* One cannot add padding options. */
+ if (type == IP6OPT_PAD1 || type == IP6OPT_PADN)
+ return -1;
+
+ /* The option length must fit in one octet. */
+ if (len > 255)
+ return -1;
+
+ /* The alignment can only by 1, 2, 4, or 8 and must not exceed the
+ option length. */
+ if (align == 0 || align > 8 || (align & (align - 1)) != 0 || align > len)
+ return -1;
+
+ /* Determine the needed padding for alignment. Following the
+ current content of the buffer we have the is the IPv6 option type
+ and length, followed immediately by the data. The data has the
+ alignment constraints. Therefore padding must be inserted in the
+ form of padding options before the new option. */
+ int data_offset = offset + sizeof (struct ip6_opt);
+ int npad = (align - data_offset % align) & (align - 1);
+
+ if (extbuf != NULL)
+ {
+ /* Now we can check whether the buffer is large enough. */
+ if (data_offset + npad + len > extlen)
+ return -1;
+
+ add_padding (extbuf, offset, npad);
+
+ offset += npad;
+
+ /* Now prepare the option itself. */
+ struct ip6_opt *opt = (struct ip6_opt *) ((uint8_t *) extbuf + offset);
+
+ opt->ip6o_type = type;
+ opt->ip6o_len = len;
+
+ *databufp = opt + 1;
+ }
+ else
+ offset += npad;
+
+ return offset + sizeof (struct ip6_opt) + len;
+}
+
+
+/* RFC 3542, 10.3
+
+ This function returns the updated total length taking into account
+ the final padding of the extension header to make it a multiple of
+ 8 bytes. If EXTBUF is not NULL the function also initializes the
+ option by inserting a Pad1 or PadN option of the proper length. */
+int
+inet6_opt_finish (void *extbuf, socklen_t extlen, int offset)
+{
+ /* Check minimum offset. */
+ if (offset < sizeof (struct ip6_hbh))
+ return -1;
+
+ /* Required padding at the end. */
+ int npad = (8 - (offset & 7)) & 7;
+
+ if (extbuf != NULL)
+ {
+ /* Make sure the buffer is large enough. */
+ if (offset + npad > extlen)
+ return -1;
+
+ add_padding (extbuf, offset, npad);
+ }
+
+ return offset + npad;
+}
+
+
+/* RFC 3542, 10.4
+
+ This function inserts data items of various sizes in the data
+ portion of the option. VAL should point to the data to be
+ inserted. OFFSET specifies where in the data portion of the option
+ the value should be inserted; the first byte after the option type
+ and length is accessed by specifying an offset of zero. */
+int
+inet6_opt_set_val (void *databuf, int offset, void *val, socklen_t vallen)
+{
+ memcpy ((uint8_t *) databuf + offset, val, vallen);
+
+ return offset + vallen;
+}
+
+
+/* RFC 3542, 10.5
+
+ This function parses received option extension headers returning
+ the next option. EXTBUF and EXTLEN specifies the extension header.
+ OFFSET should either be zero (for the first option) or the length
+ returned by a previous call to 'inet6_opt_next' or
+ 'inet6_opt_find'. It specifies the position where to continue
+ scanning the extension buffer. */
+int
+inet6_opt_next (void *extbuf, socklen_t extlen, int offset, uint8_t *typep,
+ socklen_t *lenp, void **databufp)
+{
+ if (offset == 0)
+ offset = sizeof (struct ip6_hbh);
+ else if (offset < sizeof (struct ip6_hbh))
+ return -1;
+
+ while (offset < extlen)
+ {
+ struct ip6_opt *opt = (struct ip6_opt *) ((uint8_t *) extbuf + offset);
+
+ if (opt->ip6o_type == IP6OPT_PAD1)
+ /* Single byte padding. */
+ ++offset;
+ else if (opt->ip6o_type == IP6OPT_PADN)
+ offset += sizeof (struct ip6_opt) + opt->ip6o_len;
+ else
+ {
+ /* Check whether the option is valid. */
+ offset += sizeof (struct ip6_opt) + opt->ip6o_len;
+ if (offset > extlen)
+ return -1;
+
+ *typep = opt->ip6o_type;
+ *lenp = opt->ip6o_len;
+ *databufp = opt + 1;
+ return offset;
+ }
+ }
+
+ return -1;
+}
+
+
+/* RFC 3542, 10.6
+
+ This function is similar to the previously described
+ 'inet6_opt_next' function, except this function lets the caller
+ specify the option type to be searched for, instead of always
+ returning the next option in the extension header. */
+int
+inet6_opt_find (void *extbuf, socklen_t extlen, int offset, uint8_t type,
+ socklen_t *lenp, void **databufp)
+{
+ if (offset == 0)
+ offset = sizeof (struct ip6_hbh);
+ else if (offset < sizeof (struct ip6_hbh))
+ return -1;
+
+ while (offset < extlen)
+ {
+ struct ip6_opt *opt = (struct ip6_opt *) ((uint8_t *) extbuf + offset);
+
+ if (opt->ip6o_type == IP6OPT_PAD1)
+ {
+ /* Single byte padding. */
+ ++offset;
+ if (type == IP6OPT_PAD1)
+ {
+ *lenp = 0;
+ *databufp = (uint8_t *) extbuf + offset;
+ return offset;
+ }
+ }
+ else if (opt->ip6o_type != type)
+ offset += sizeof (struct ip6_opt) + opt->ip6o_len;
+ else
+ {
+ /* Check whether the option is valid. */
+ offset += sizeof (struct ip6_opt) + opt->ip6o_len;
+ if (offset > extlen)
+ return -1;
+
+ *lenp = opt->ip6o_len;
+ *databufp = opt + 1;
+ return offset;
+ }
+ }
+
+ return -1;
+}
+
+
+/* RFC 3542, 10.7
+
+ This function extracts data items of various sizes in the data
+ portion of the option. */
+int
+inet6_opt_get_val (void *databuf, int offset, void *val, socklen_t vallen)
+{
+ memcpy (val, (uint8_t *) databuf + offset, vallen);
+
+ return offset + vallen;
+}