129 lines
5.5 KiB
C
129 lines
5.5 KiB
C
/* $NetBSD: extract.h,v 1.3 2007/07/24 11:53:38 drochner Exp $ */
|
|
|
|
/*
|
|
* Copyright (c) 1992, 1993, 1994, 1995, 1996
|
|
* The Regents of the University of California. All rights reserved.
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that: (1) source code distributions
|
|
* retain the above copyright notice and this paragraph in its entirety, (2)
|
|
* distributions including binary code include the above copyright notice and
|
|
* this paragraph in its entirety in the documentation or other materials
|
|
* provided with the distribution, and (3) all advertising materials mentioning
|
|
* features or use of this software display the following acknowledgement:
|
|
* ``This product includes software developed by the University of California,
|
|
* Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
|
|
* the University nor the names of its contributors may be used to endorse
|
|
* or promote products derived from this software without specific prior
|
|
* written permission.
|
|
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
|
|
* WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
|
|
* MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
|
|
*
|
|
* @(#) Header: /tcpdump/master/tcpdump/extract.h,v 1.24 2005/01/15 02:06:50 guy Exp (LBL)
|
|
*/
|
|
|
|
/*
|
|
* Macros to extract possibly-unaligned big-endian integral values.
|
|
*/
|
|
#ifdef LBL_ALIGN
|
|
/*
|
|
* The processor doesn't natively handle unaligned loads.
|
|
*/
|
|
#ifdef HAVE___ATTRIBUTE__
|
|
/*
|
|
* We have __attribute__; we assume that means we have __attribute__((packed)).
|
|
* Declare packed structures containing a u_int16_t and a u_int32_t,
|
|
* cast the pointer to point to one of those, and fetch through it;
|
|
* the GCC manual doesn't appear to explicitly say that
|
|
* __attribute__((packed)) causes the compiler to generate unaligned-safe
|
|
* code, but it apppears to do so.
|
|
*
|
|
* We do this in case the compiler can generate, for this instruction set,
|
|
* better code to do an unaligned load and pass stuff to "ntohs()" or
|
|
* "ntohl()" than the code to fetch the bytes one at a time and
|
|
* assemble them. (That might not be the case on a little-endian platform,
|
|
* where "ntohs()" and "ntohl()" might not be done inline.)
|
|
*/
|
|
typedef struct {
|
|
u_int16_t val;
|
|
} __attribute__((packed)) unaligned_u_int16_t;
|
|
|
|
typedef struct {
|
|
u_int32_t val;
|
|
} __attribute__((packed)) unaligned_u_int32_t;
|
|
|
|
#define EXTRACT_16BITS(p) \
|
|
((u_int16_t)ntohs(((const unaligned_u_int16_t *)(p))->val))
|
|
#define EXTRACT_32BITS(p) \
|
|
((u_int32_t)ntohl(((const unaligned_u_int32_t *)(p))->val))
|
|
#define EXTRACT_64BITS(p) \
|
|
((u_int64_t)(((u_int64_t)ntohl(((const unaligned_u_int32_t *)(p) + 0)->val)) << 32 | \
|
|
((u_int64_t)ntohl(((const unaligned_u_int32_t *)(p) + 1)->val)) << 0))
|
|
|
|
#else /* HAVE___ATTRIBUTE__ */
|
|
/*
|
|
* We don't have __attribute__, so do unaligned loads of big-endian
|
|
* quantities the hard way - fetch the bytes one at a time and
|
|
* assemble them.
|
|
*/
|
|
#define EXTRACT_16BITS(p) \
|
|
((u_int16_t)((u_int16_t)*((const u_int8_t *)(p) + 0) << 8 | \
|
|
(u_int16_t)*((const u_int8_t *)(p) + 1)))
|
|
#define EXTRACT_32BITS(p) \
|
|
((u_int32_t)((u_int32_t)*((const u_int8_t *)(p) + 0) << 24 | \
|
|
(u_int32_t)*((const u_int8_t *)(p) + 1) << 16 | \
|
|
(u_int32_t)*((const u_int8_t *)(p) + 2) << 8 | \
|
|
(u_int32_t)*((const u_int8_t *)(p) + 3)))
|
|
#define EXTRACT_64BITS(p) \
|
|
((u_int64_t)((u_int64_t)*((const u_int8_t *)(p) + 0) << 56 | \
|
|
(u_int64_t)*((const u_int8_t *)(p) + 1) << 48 | \
|
|
(u_int64_t)*((const u_int8_t *)(p) + 2) << 40 | \
|
|
(u_int64_t)*((const u_int8_t *)(p) + 3) << 32 | \
|
|
(u_int64_t)*((const u_int8_t *)(p) + 4) << 24 | \
|
|
(u_int64_t)*((const u_int8_t *)(p) + 5) << 16 | \
|
|
(u_int64_t)*((const u_int8_t *)(p) + 6) << 8 | \
|
|
(u_int64_t)*((const u_int8_t *)(p) + 7)))
|
|
#endif /* HAVE___ATTRIBUTE__ */
|
|
#else /* LBL_ALIGN */
|
|
/*
|
|
* The processor natively handles unaligned loads, so we can just
|
|
* cast the pointer and fetch through it.
|
|
*/
|
|
#define EXTRACT_16BITS(p) \
|
|
((u_int16_t)ntohs(*(const u_int16_t *)(p)))
|
|
#define EXTRACT_32BITS(p) \
|
|
((u_int32_t)ntohl(*(const u_int32_t *)(p)))
|
|
#define EXTRACT_64BITS(p) \
|
|
((u_int64_t)(((u_int64_t)ntohl(*((const u_int32_t *)(p) + 0))) << 32 | \
|
|
((u_int64_t)ntohl(*((const u_int32_t *)(p) + 1))) << 0))
|
|
#endif /* LBL_ALIGN */
|
|
|
|
#define EXTRACT_24BITS(p) \
|
|
((u_int32_t)((u_int32_t)*((const u_int8_t *)(p) + 0) << 16 | \
|
|
(u_int32_t)*((const u_int8_t *)(p) + 1) << 8 | \
|
|
(u_int32_t)*((const u_int8_t *)(p) + 2)))
|
|
|
|
/*
|
|
* Macros to extract possibly-unaligned little-endian integral values.
|
|
* XXX - do loads on little-endian machines that support unaligned loads?
|
|
*/
|
|
#define EXTRACT_LE_8BITS(p) (*(p))
|
|
#define EXTRACT_LE_16BITS(p) \
|
|
((u_int16_t)((u_int16_t)*((const u_int8_t *)(p) + 1) << 8 | \
|
|
(u_int16_t)*((const u_int8_t *)(p) + 0)))
|
|
#define EXTRACT_LE_32BITS(p) \
|
|
((u_int32_t)((u_int32_t)*((const u_int8_t *)(p) + 3) << 24 | \
|
|
(u_int32_t)*((const u_int8_t *)(p) + 2) << 16 | \
|
|
(u_int32_t)*((const u_int8_t *)(p) + 1) << 8 | \
|
|
(u_int32_t)*((const u_int8_t *)(p) + 0)))
|
|
#define EXTRACT_LE_64BITS(p) \
|
|
((u_int64_t)((u_int64_t)*((const u_int8_t *)(p) + 7) << 56 | \
|
|
(u_int64_t)*((const u_int8_t *)(p) + 6) << 48 | \
|
|
(u_int64_t)*((const u_int8_t *)(p) + 5) << 40 | \
|
|
(u_int64_t)*((const u_int8_t *)(p) + 4) << 32 | \
|
|
(u_int64_t)*((const u_int8_t *)(p) + 3) << 24 | \
|
|
(u_int64_t)*((const u_int8_t *)(p) + 2) << 16 | \
|
|
(u_int64_t)*((const u_int8_t *)(p) + 1) << 8 | \
|
|
(u_int64_t)*((const u_int8_t *)(p) + 0)))
|