/* * 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 1.25 2006-01-30 16:20:07 hannes 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_24BITS(p) \	((u_int32_t)((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)))