14edb46e9SPaul Traina /* 24edb46e9SPaul Traina * Copyright (c) 1992, 1993, 1994, 1995, 1996 34edb46e9SPaul Traina * The Regents of the University of California. All rights reserved. 44edb46e9SPaul Traina * 54edb46e9SPaul Traina * Redistribution and use in source and binary forms, with or without 64edb46e9SPaul Traina * modification, are permitted provided that: (1) source code distributions 74edb46e9SPaul Traina * retain the above copyright notice and this paragraph in its entirety, (2) 84edb46e9SPaul Traina * distributions including binary code include the above copyright notice and 94edb46e9SPaul Traina * this paragraph in its entirety in the documentation or other materials 104edb46e9SPaul Traina * provided with the distribution, and (3) all advertising materials mentioning 114edb46e9SPaul Traina * features or use of this software display the following acknowledgement: 124edb46e9SPaul Traina * ``This product includes software developed by the University of California, 134edb46e9SPaul Traina * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of 144edb46e9SPaul Traina * the University nor the names of its contributors may be used to endorse 154edb46e9SPaul Traina * or promote products derived from this software without specific prior 164edb46e9SPaul Traina * written permission. 174edb46e9SPaul Traina * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED 184edb46e9SPaul Traina * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF 194edb46e9SPaul Traina * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 204edb46e9SPaul Traina * 21a5779b6eSRui Paulo * @(#) $Header: /tcpdump/master/tcpdump/extract.h,v 1.25 2006-01-30 16:20:07 hannes Exp $ (LBL) 224edb46e9SPaul Traina */ 234edb46e9SPaul Traina 241de50e9fSSam Leffler /* 251de50e9fSSam Leffler * Macros to extract possibly-unaligned big-endian integral values. 261de50e9fSSam Leffler */ 274edb46e9SPaul Traina #ifdef LBL_ALIGN 285b0fe478SBruce M Simpson /* 295b0fe478SBruce M Simpson * The processor doesn't natively handle unaligned loads. 305b0fe478SBruce M Simpson */ 315b0fe478SBruce M Simpson #ifdef HAVE___ATTRIBUTE__ 325b0fe478SBruce M Simpson /* 335b0fe478SBruce M Simpson * We have __attribute__; we assume that means we have __attribute__((packed)). 345b0fe478SBruce M Simpson * Declare packed structures containing a u_int16_t and a u_int32_t, 355b0fe478SBruce M Simpson * cast the pointer to point to one of those, and fetch through it; 365b0fe478SBruce M Simpson * the GCC manual doesn't appear to explicitly say that 375b0fe478SBruce M Simpson * __attribute__((packed)) causes the compiler to generate unaligned-safe 385b0fe478SBruce M Simpson * code, but it apppears to do so. 395b0fe478SBruce M Simpson * 405b0fe478SBruce M Simpson * We do this in case the compiler can generate, for this instruction set, 415b0fe478SBruce M Simpson * better code to do an unaligned load and pass stuff to "ntohs()" or 425b0fe478SBruce M Simpson * "ntohl()" than the code to fetch the bytes one at a time and 435b0fe478SBruce M Simpson * assemble them. (That might not be the case on a little-endian platform, 445b0fe478SBruce M Simpson * where "ntohs()" and "ntohl()" might not be done inline.) 455b0fe478SBruce M Simpson */ 465b0fe478SBruce M Simpson typedef struct { 475b0fe478SBruce M Simpson u_int16_t val; 485b0fe478SBruce M Simpson } __attribute__((packed)) unaligned_u_int16_t; 495b0fe478SBruce M Simpson 505b0fe478SBruce M Simpson typedef struct { 515b0fe478SBruce M Simpson u_int32_t val; 525b0fe478SBruce M Simpson } __attribute__((packed)) unaligned_u_int32_t; 535b0fe478SBruce M Simpson 54*340b3427SPedro F. Giffuni static inline u_int16_t 55*340b3427SPedro F. Giffuni EXTRACT_16BITS(const void *p) 56*340b3427SPedro F. Giffuni { 57*340b3427SPedro F. Giffuni return ((u_int16_t)ntohs(((const unaligned_u_int16_t *)(p))->val)); 58*340b3427SPedro F. Giffuni } 59*340b3427SPedro F. Giffuni 60*340b3427SPedro F. Giffuni static inline u_int32_t 61*340b3427SPedro F. Giffuni EXTRACT_32BITS(const void *p) 62*340b3427SPedro F. Giffuni { 63*340b3427SPedro F. Giffuni return ((u_int32_t)ntohl(((const unaligned_u_int32_t *)(p))->val)); 64*340b3427SPedro F. Giffuni } 65*340b3427SPedro F. Giffuni 66*340b3427SPedro F. Giffuni static inline u_int64_t 67*340b3427SPedro F. Giffuni EXTRACT_64BITS(const void *p) 68*340b3427SPedro F. Giffuni { 69*340b3427SPedro F. Giffuni return ((u_int64_t)(((u_int64_t)ntohl(((const unaligned_u_int32_t *)(p) + 0)->val)) << 32 | \ 70*340b3427SPedro F. Giffuni ((u_int64_t)ntohl(((const unaligned_u_int32_t *)(p) + 1)->val)) << 0)); 71*340b3427SPedro F. Giffuni 72*340b3427SPedro F. Giffuni } 731de50e9fSSam Leffler 745b0fe478SBruce M Simpson #else /* HAVE___ATTRIBUTE__ */ 755b0fe478SBruce M Simpson /* 765b0fe478SBruce M Simpson * We don't have __attribute__, so do unaligned loads of big-endian 775b0fe478SBruce M Simpson * quantities the hard way - fetch the bytes one at a time and 785b0fe478SBruce M Simpson * assemble them. 795b0fe478SBruce M Simpson */ 805b0fe478SBruce M Simpson #define EXTRACT_16BITS(p) \ 815b0fe478SBruce M Simpson ((u_int16_t)((u_int16_t)*((const u_int8_t *)(p) + 0) << 8 | \ 825b0fe478SBruce M Simpson (u_int16_t)*((const u_int8_t *)(p) + 1))) 835b0fe478SBruce M Simpson #define EXTRACT_32BITS(p) \ 845b0fe478SBruce M Simpson ((u_int32_t)((u_int32_t)*((const u_int8_t *)(p) + 0) << 24 | \ 85a90e161bSBill Fenner (u_int32_t)*((const u_int8_t *)(p) + 1) << 16 | \ 86a90e161bSBill Fenner (u_int32_t)*((const u_int8_t *)(p) + 2) << 8 | \ 875b0fe478SBruce M Simpson (u_int32_t)*((const u_int8_t *)(p) + 3))) 881de50e9fSSam Leffler #define EXTRACT_64BITS(p) \ 891de50e9fSSam Leffler ((u_int64_t)((u_int64_t)*((const u_int8_t *)(p) + 0) << 56 | \ 901de50e9fSSam Leffler (u_int64_t)*((const u_int8_t *)(p) + 1) << 48 | \ 911de50e9fSSam Leffler (u_int64_t)*((const u_int8_t *)(p) + 2) << 40 | \ 921de50e9fSSam Leffler (u_int64_t)*((const u_int8_t *)(p) + 3) << 32 | \ 931de50e9fSSam Leffler (u_int64_t)*((const u_int8_t *)(p) + 4) << 24 | \ 941de50e9fSSam Leffler (u_int64_t)*((const u_int8_t *)(p) + 5) << 16 | \ 951de50e9fSSam Leffler (u_int64_t)*((const u_int8_t *)(p) + 6) << 8 | \ 961de50e9fSSam Leffler (u_int64_t)*((const u_int8_t *)(p) + 7))) 975b0fe478SBruce M Simpson #endif /* HAVE___ATTRIBUTE__ */ 985b0fe478SBruce M Simpson #else /* LBL_ALIGN */ 995b0fe478SBruce M Simpson /* 1005b0fe478SBruce M Simpson * The processor natively handles unaligned loads, so we can just 1015b0fe478SBruce M Simpson * cast the pointer and fetch through it. 1025b0fe478SBruce M Simpson */ 103*340b3427SPedro F. Giffuni static inline u_int16_t 104*340b3427SPedro F. Giffuni EXTRACT_16BITS(const void *p) 105*340b3427SPedro F. Giffuni { 106*340b3427SPedro F. Giffuni return ((u_int16_t)ntohs(*(const u_int16_t *)(p))); 107*340b3427SPedro F. Giffuni } 108*340b3427SPedro F. Giffuni 109*340b3427SPedro F. Giffuni static inline u_int32_t 110*340b3427SPedro F. Giffuni EXTRACT_32BITS(const void *p) 111*340b3427SPedro F. Giffuni { 112*340b3427SPedro F. Giffuni return ((u_int32_t)ntohl(*(const u_int32_t *)(p))); 113*340b3427SPedro F. Giffuni } 114*340b3427SPedro F. Giffuni 115*340b3427SPedro F. Giffuni static inline u_int64_t 116*340b3427SPedro F. Giffuni EXTRACT_64BITS(const void *p) 117*340b3427SPedro F. Giffuni { 118*340b3427SPedro F. Giffuni return ((u_int64_t)(((u_int64_t)ntohl(*((const u_int32_t *)(p) + 0))) << 32 | \ 119*340b3427SPedro F. Giffuni ((u_int64_t)ntohl(*((const u_int32_t *)(p) + 1))) << 0)); 120*340b3427SPedro F. Giffuni 121*340b3427SPedro F. Giffuni } 122*340b3427SPedro F. Giffuni 1235b0fe478SBruce M Simpson #endif /* LBL_ALIGN */ 1244edb46e9SPaul Traina 1254edb46e9SPaul Traina #define EXTRACT_24BITS(p) \ 1265b0fe478SBruce M Simpson ((u_int32_t)((u_int32_t)*((const u_int8_t *)(p) + 0) << 16 | \ 127a90e161bSBill Fenner (u_int32_t)*((const u_int8_t *)(p) + 1) << 8 | \ 1285b0fe478SBruce M Simpson (u_int32_t)*((const u_int8_t *)(p) + 2))) 1294edb46e9SPaul Traina 1301de50e9fSSam Leffler /* 1311de50e9fSSam Leffler * Macros to extract possibly-unaligned little-endian integral values. 1321de50e9fSSam Leffler * XXX - do loads on little-endian machines that support unaligned loads? 1331de50e9fSSam Leffler */ 1344edb46e9SPaul Traina #define EXTRACT_LE_8BITS(p) (*(p)) 1354edb46e9SPaul Traina #define EXTRACT_LE_16BITS(p) \ 1365b0fe478SBruce M Simpson ((u_int16_t)((u_int16_t)*((const u_int8_t *)(p) + 1) << 8 | \ 1375b0fe478SBruce M Simpson (u_int16_t)*((const u_int8_t *)(p) + 0))) 1384edb46e9SPaul Traina #define EXTRACT_LE_32BITS(p) \ 1395b0fe478SBruce M Simpson ((u_int32_t)((u_int32_t)*((const u_int8_t *)(p) + 3) << 24 | \ 140a90e161bSBill Fenner (u_int32_t)*((const u_int8_t *)(p) + 2) << 16 | \ 141a90e161bSBill Fenner (u_int32_t)*((const u_int8_t *)(p) + 1) << 8 | \ 1425b0fe478SBruce M Simpson (u_int32_t)*((const u_int8_t *)(p) + 0))) 143a5779b6eSRui Paulo #define EXTRACT_LE_24BITS(p) \ 144a5779b6eSRui Paulo ((u_int32_t)((u_int32_t)*((const u_int8_t *)(p) + 2) << 16 | \ 145a5779b6eSRui Paulo (u_int32_t)*((const u_int8_t *)(p) + 1) << 8 | \ 146a5779b6eSRui Paulo (u_int32_t)*((const u_int8_t *)(p) + 0))) 1471de50e9fSSam Leffler #define EXTRACT_LE_64BITS(p) \ 1481de50e9fSSam Leffler ((u_int64_t)((u_int64_t)*((const u_int8_t *)(p) + 7) << 56 | \ 1491de50e9fSSam Leffler (u_int64_t)*((const u_int8_t *)(p) + 6) << 48 | \ 1501de50e9fSSam Leffler (u_int64_t)*((const u_int8_t *)(p) + 5) << 40 | \ 1511de50e9fSSam Leffler (u_int64_t)*((const u_int8_t *)(p) + 4) << 32 | \ 1521de50e9fSSam Leffler (u_int64_t)*((const u_int8_t *)(p) + 3) << 24 | \ 1531de50e9fSSam Leffler (u_int64_t)*((const u_int8_t *)(p) + 2) << 16 | \ 1541de50e9fSSam Leffler (u_int64_t)*((const u_int8_t *)(p) + 1) << 8 | \ 1551de50e9fSSam Leffler (u_int64_t)*((const u_int8_t *)(p) + 0))) 156