tcpdump/cpack.c
Guy Harris 54db122321 Support RX flags, MCS and the vendor namespace, and fix Rate.
Based on patches from an anonymous donor, support the radiotap RX flags and
MCS fields, and the vendor namespace, and, if Channel and XChannel are
both present, use XChannel, not Channel.

Do not try to look up a rate for an MCS value from the Rate field; you
cannot map an MCS value to a rate without also knowing the channel width
and guard interval length.
2011-04-27 12:08:27 -07:00

145 lines
3.6 KiB
C

/*-
* Copyright (c) 2003, 2004 David Young. 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. The name of David Young may not be used to endorse or promote
* products derived from this software without specific prior
* written permission.
*
* THIS SOFTWARE IS PROVIDED BY DAVID YOUNG ``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 DAVID
* YOUNG 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.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <stdlib.h>
#include <string.h>
#include <tcpdump-stdinc.h>
#include "cpack.h"
#include "extract.h"
u_int8_t *
cpack_next_boundary(u_int8_t *buf, u_int8_t *p, size_t alignment)
{
size_t misalignment = (size_t)(p - buf) % alignment;
if (misalignment == 0)
return p;
return p + (alignment - misalignment);
}
/* Advance to the next wordsize boundary. Return NULL if fewer than
* wordsize bytes remain in the buffer after the boundary. Otherwise,
* return a pointer to the boundary.
*/
u_int8_t *
cpack_align_and_reserve(struct cpack_state *cs, size_t wordsize)
{
u_int8_t *next;
/* Ensure alignment. */
next = cpack_next_boundary(cs->c_buf, cs->c_next, wordsize);
/* Too little space for wordsize bytes? */
if (next - cs->c_buf + wordsize > cs->c_len)
return NULL;
return next;
}
int
cpack_init(struct cpack_state *cs, u_int8_t *buf, size_t buflen)
{
memset(cs, 0, sizeof(*cs));
cs->c_buf = buf;
cs->c_len = buflen;
cs->c_next = cs->c_buf;
return 0;
}
/* Unpack a 64-bit unsigned integer. */
int
cpack_uint64(struct cpack_state *cs, u_int64_t *u)
{
u_int8_t *next;
if ((next = cpack_align_and_reserve(cs, sizeof(*u))) == NULL)
return -1;
*u = EXTRACT_LE_64BITS(next);
/* Move pointer past the u_int64_t. */
cs->c_next = next + sizeof(*u);
return 0;
}
/* Unpack a 32-bit unsigned integer. */
int
cpack_uint32(struct cpack_state *cs, u_int32_t *u)
{
u_int8_t *next;
if ((next = cpack_align_and_reserve(cs, sizeof(*u))) == NULL)
return -1;
*u = EXTRACT_LE_32BITS(next);
/* Move pointer past the u_int32_t. */
cs->c_next = next + sizeof(*u);
return 0;
}
/* Unpack a 16-bit unsigned integer. */
int
cpack_uint16(struct cpack_state *cs, u_int16_t *u)
{
u_int8_t *next;
if ((next = cpack_align_and_reserve(cs, sizeof(*u))) == NULL)
return -1;
*u = EXTRACT_LE_16BITS(next);
/* Move pointer past the u_int16_t. */
cs->c_next = next + sizeof(*u);
return 0;
}
/* Unpack an 8-bit unsigned integer. */
int
cpack_uint8(struct cpack_state *cs, u_int8_t *u)
{
/* No space left? */
if ((size_t)(cs->c_next - cs->c_buf) >= cs->c_len)
return -1;
*u = *cs->c_next;
/* Move pointer past the u_int8_t. */
cs->c_next++;
return 0;
}