diff options
Diffstat (limited to 'extract.h')
| -rw-r--r-- | extract.h | 225 |
1 files changed, 225 insertions, 0 deletions
diff --git a/extract.h b/extract.h new file mode 100644 index 0000000..aa3ff99 --- /dev/null +++ b/extract.h @@ -0,0 +1,225 @@ +/* + * 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 <arpa/inet.h> +#endif + +#include <pcap/pcap-inttypes.h> +#include <pcap/compiler-tests.h> + +/* + * 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))) |