/* * 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. */ #ifndef _WIN32 #include #endif #include #include /* * Macros to extract possibly-unaligned big-endian integral values. */ #ifdef LBL_ALIGN /* * The processor doesn't natively handle unaligned loads. */ #if PCAP_IS_AT_LEAST_GNUC_VERSION(2,0) && \ (defined(__alpha) || defined(__alpha__) || \ defined(__mips) || defined(__mips__)) /* * This is MIPS or Alpha, which don't natively handle unaligned loads, * but which have instructions that can help when doing unaligned * loads, and this is GCC 2.0 or later or a compiler that claims to * be GCC 2.0 or later, which we assume that mean we have * __attribute__((packed)), which we can use to convince the compiler * to generate those instructions. * * Declare packed structures containing a uint16_t and a uint32_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 code using those * instructions to do an unaligned load and pass stuff to "ntohs()" or * "ntohl()", which might be better than 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, such as DEC's MIPS machines and * Alpha machines, where "ntohs()" and "ntohl()" might not be done * inline.) * * We do this only for specific architectures because, for example, * at least some versions of GCC, when compiling for 64-bit SPARC, * generate code that assumes alignment if we do this. * * XXX - add other architectures and compilers as possible and * appropriate. * * HP's C compiler, indicated by __HP_cc being defined, supports * "#pragma unaligned N" in version A.05.50 and later, where "N" * specifies a number of bytes at which the typedef on the next * line is aligned, e.g. * * #pragma unalign 1 * typedef uint16_t unaligned_uint16_t; * * to define unaligned_uint16_t as a 16-bit unaligned data type. * This could be presumably used, in sufficiently recent versions of * the compiler, with macros similar to those below. This would be * useful only if that compiler could generate better code for PA-RISC * or Itanium than would be generated by a bunch of shifts-and-ORs. * * DEC C, indicated by __DECC being defined, has, at least on Alpha, * an __unaligned qualifier that can be applied to pointers to get the * compiler to generate code that does unaligned loads and stores when * dereferencing the pointer in question. * * XXX - what if the native C compiler doesn't support * __attribute__((packed))? How can we get it to generate unaligned * accesses for *specific* items? */ typedef struct { uint16_t val; } __attribute__((packed)) unaligned_uint16_t; typedef struct { uint32_t val; } __attribute__((packed)) unaligned_uint32_t; static inline uint16_t EXTRACT_16BITS(const void *p) { return ((uint16_t)ntohs(((const unaligned_uint16_t *)(p))->val)); } static inline uint32_t EXTRACT_32BITS(const void *p) { return ((uint32_t)ntohl(((const unaligned_uint32_t *)(p))->val)); } static inline uint64_t EXTRACT_64BITS(const void *p) { return ((uint64_t)(((uint64_t)ntohl(((const unaligned_uint32_t *)(p) + 0)->val)) << 32 | \ ((uint64_t)ntohl(((const unaligned_uint32_t *)(p) + 1)->val)) << 0)); } #else /* have to do it a byte at a time */ /* * This isn't a GCC-compatible compiler, we don't have __attribute__, * or we do but we don't know of any better way with this instruction * set to do unaligned loads, 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) \ ((uint16_t)(((uint16_t)(*((const uint8_t *)(p) + 0)) << 8) | \ ((uint16_t)(*((const uint8_t *)(p) + 1)) << 0))) #define EXTRACT_32BITS(p) \ ((uint32_t)(((uint32_t)(*((const uint8_t *)(p) + 0)) << 24) | \ ((uint32_t)(*((const uint8_t *)(p) + 1)) << 16) | \ ((uint32_t)(*((const uint8_t *)(p) + 2)) << 8) | \ ((uint32_t)(*((const uint8_t *)(p) + 3)) << 0))) #define EXTRACT_64BITS(p) \ ((uint64_t)(((uint64_t)(*((const uint8_t *)(p) + 0)) << 56) | \ ((uint64_t)(*((const uint8_t *)(p) + 1)) << 48) | \ ((uint64_t)(*((const uint8_t *)(p) + 2)) << 40) | \ ((uint64_t)(*((const uint8_t *)(p) + 3)) << 32) | \ ((uint64_t)(*((const uint8_t *)(p) + 4)) << 24) | \ ((uint64_t)(*((const uint8_t *)(p) + 5)) << 16) | \ ((uint64_t)(*((const uint8_t *)(p) + 6)) << 8) | \ ((uint64_t)(*((const uint8_t *)(p) + 7)) << 0))) #endif /* must special-case unaligned accesses */ #else /* LBL_ALIGN */ /* * The processor natively handles unaligned loads, so we can just * cast the pointer and fetch through it. */ static inline uint16_t EXTRACT_16BITS(const void *p) { return ((uint16_t)ntohs(*(const uint16_t *)(p))); } static inline uint32_t EXTRACT_32BITS(const void *p) { return ((uint32_t)ntohl(*(const uint32_t *)(p))); } static inline uint64_t EXTRACT_64BITS(const void *p) { return ((uint64_t)(((uint64_t)ntohl(*((const uint32_t *)(p) + 0))) << 32 | \ ((uint64_t)ntohl(*((const uint32_t *)(p) + 1))) << 0)); } #endif /* LBL_ALIGN */ #define EXTRACT_24BITS(p) \ ((uint32_t)(((uint32_t)(*((const uint8_t *)(p) + 0)) << 16) | \ ((uint32_t)(*((const uint8_t *)(p) + 1)) << 8) | \ ((uint32_t)(*((const uint8_t *)(p) + 2)) << 0))) #define EXTRACT_40BITS(p) \ ((uint64_t)(((uint64_t)(*((const uint8_t *)(p) + 0)) << 32) | \ ((uint64_t)(*((const uint8_t *)(p) + 1)) << 24) | \ ((uint64_t)(*((const uint8_t *)(p) + 2)) << 16) | \ ((uint64_t)(*((const uint8_t *)(p) + 3)) << 8) | \ ((uint64_t)(*((const uint8_t *)(p) + 4)) << 0))) #define EXTRACT_48BITS(p) \ ((uint64_t)(((uint64_t)(*((const uint8_t *)(p) + 0)) << 40) | \ ((uint64_t)(*((const uint8_t *)(p) + 1)) << 32) | \ ((uint64_t)(*((const uint8_t *)(p) + 2)) << 24) | \ ((uint64_t)(*((const uint8_t *)(p) + 3)) << 16) | \ ((uint64_t)(*((const uint8_t *)(p) + 4)) << 8) | \ ((uint64_t)(*((const uint8_t *)(p) + 5)) << 0))) #define EXTRACT_56BITS(p) \ ((uint64_t)(((uint64_t)(*((const uint8_t *)(p) + 0)) << 48) | \ ((uint64_t)(*((const uint8_t *)(p) + 1)) << 40) | \ ((uint64_t)(*((const uint8_t *)(p) + 2)) << 32) | \ ((uint64_t)(*((const uint8_t *)(p) + 3)) << 24) | \ ((uint64_t)(*((const uint8_t *)(p) + 4)) << 16) | \ ((uint64_t)(*((const uint8_t *)(p) + 5)) << 8) | \ ((uint64_t)(*((const uint8_t *)(p) + 6)) << 0))) /* * 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) \ ((uint16_t)(((uint16_t)(*((const uint8_t *)(p) + 1)) << 8) | \ ((uint16_t)(*((const uint8_t *)(p) + 0)) << 0))) #define EXTRACT_LE_32BITS(p) \ ((uint32_t)(((uint32_t)(*((const uint8_t *)(p) + 3)) << 24) | \ ((uint32_t)(*((const uint8_t *)(p) + 2)) << 16) | \ ((uint32_t)(*((const uint8_t *)(p) + 1)) << 8) | \ ((uint32_t)(*((const uint8_t *)(p) + 0)) << 0))) #define EXTRACT_LE_24BITS(p) \ ((uint32_t)(((uint32_t)(*((const uint8_t *)(p) + 2)) << 16) | \ ((uint32_t)(*((const uint8_t *)(p) + 1)) << 8) | \ ((uint32_t)(*((const uint8_t *)(p) + 0)) << 0))) #define EXTRACT_LE_64BITS(p) \ ((uint64_t)(((uint64_t)(*((const uint8_t *)(p) + 7)) << 56) | \ ((uint64_t)(*((const uint8_t *)(p) + 6)) << 48) | \ ((uint64_t)(*((const uint8_t *)(p) + 5)) << 40) | \ ((uint64_t)(*((const uint8_t *)(p) + 4)) << 32) | \ ((uint64_t)(*((const uint8_t *)(p) + 3)) << 24) | \ ((uint64_t)(*((const uint8_t *)(p) + 2)) << 16) | \ ((uint64_t)(*((const uint8_t *)(p) + 1)) << 8) | \ ((uint64_t)(*((const uint8_t *)(p) + 0)) << 0)))