Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (c) 1992, 1993, 1994, 1995, 1996 |
| 3 | * The Regents of the University of California. All rights reserved. |
| 4 | * |
| 5 | * Redistribution and use in source and binary forms, with or without |
| 6 | * modification, are permitted provided that: (1) source code distributions |
| 7 | * retain the above copyright notice and this paragraph in its entirety, (2) |
| 8 | * distributions including binary code include the above copyright notice and |
| 9 | * this paragraph in its entirety in the documentation or other materials |
| 10 | * provided with the distribution, and (3) all advertising materials mentioning |
| 11 | * features or use of this software display the following acknowledgement: |
| 12 | * ``This product includes software developed by the University of California, |
| 13 | * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of |
| 14 | * the University nor the names of its contributors may be used to endorse |
| 15 | * or promote products derived from this software without specific prior |
| 16 | * written permission. |
| 17 | * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED |
| 18 | * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF |
| 19 | * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. |
| 20 | */ |
| 21 | |
| 22 | #ifndef _WIN32 |
| 23 | #include <arpa/inet.h> |
| 24 | #endif |
| 25 | |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 26 | #include <pcap/pcap-inttypes.h> |
| 27 | #include <pcap/compiler-tests.h> |
| 28 | |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 29 | /* |
| 30 | * Macros to extract possibly-unaligned big-endian integral values. |
| 31 | */ |
| 32 | #ifdef LBL_ALIGN |
| 33 | /* |
| 34 | * The processor doesn't natively handle unaligned loads. |
| 35 | */ |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 36 | #if PCAP_IS_AT_LEAST_GNUC_VERSION(2,0) && \ |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 37 | (defined(__alpha) || defined(__alpha__) || \ |
| 38 | defined(__mips) || defined(__mips__)) |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 39 | /* |
Haibo Huang | 165065a | 2018-07-23 17:26:52 -0700 | [diff] [blame] | 40 | * This is MIPS or Alpha, which don't natively handle unaligned loads, |
| 41 | * but which have instructions that can help when doing unaligned |
| 42 | * loads, and this is GCC 2.0 or later or a compiler that claims to |
| 43 | * be GCC 2.0 or later, which we assume that mean we have |
| 44 | * __attribute__((packed)), which we can use to convince the compiler |
| 45 | * to generate those instructions. |
Elliott Hughes | 965a4b5 | 2017-05-15 10:37:39 -0700 | [diff] [blame] | 46 | * |
| 47 | * Declare packed structures containing a uint16_t and a uint32_t, |
| 48 | * cast the pointer to point to one of those, and fetch through it; |
| 49 | * the GCC manual doesn't appear to explicitly say that |
| 50 | * __attribute__((packed)) causes the compiler to generate unaligned-safe |
| 51 | * code, but it apppears to do so. |
| 52 | * |
| 53 | * We do this in case the compiler can generate code using those |
| 54 | * instructions to do an unaligned load and pass stuff to "ntohs()" or |
| 55 | * "ntohl()", which might be better than than the code to fetch the |
| 56 | * bytes one at a time and assemble them. (That might not be the |
| 57 | * case on a little-endian platform, such as DEC's MIPS machines and |
| 58 | * Alpha machines, where "ntohs()" and "ntohl()" might not be done |
| 59 | * inline.) |
| 60 | * |
| 61 | * We do this only for specific architectures because, for example, |
| 62 | * at least some versions of GCC, when compiling for 64-bit SPARC, |
| 63 | * generate code that assumes alignment if we do this. |
| 64 | * |
| 65 | * XXX - add other architectures and compilers as possible and |
| 66 | * appropriate. |
| 67 | * |
| 68 | * HP's C compiler, indicated by __HP_cc being defined, supports |
| 69 | * "#pragma unaligned N" in version A.05.50 and later, where "N" |
| 70 | * specifies a number of bytes at which the typedef on the next |
| 71 | * line is aligned, e.g. |
| 72 | * |
| 73 | * #pragma unalign 1 |
| 74 | * typedef uint16_t unaligned_uint16_t; |
| 75 | * |
| 76 | * to define unaligned_uint16_t as a 16-bit unaligned data type. |
| 77 | * This could be presumably used, in sufficiently recent versions of |
| 78 | * the compiler, with macros similar to those below. This would be |
| 79 | * useful only if that compiler could generate better code for PA-RISC |
| 80 | * or Itanium than would be generated by a bunch of shifts-and-ORs. |
| 81 | * |
| 82 | * DEC C, indicated by __DECC being defined, has, at least on Alpha, |
| 83 | * an __unaligned qualifier that can be applied to pointers to get the |
| 84 | * compiler to generate code that does unaligned loads and stores when |
| 85 | * dereferencing the pointer in question. |
| 86 | * |
| 87 | * XXX - what if the native C compiler doesn't support |
| 88 | * __attribute__((packed))? How can we get it to generate unaligned |
| 89 | * accesses for *specific* items? |
| 90 | */ |
| 91 | typedef struct { |
| 92 | uint16_t val; |
| 93 | } __attribute__((packed)) unaligned_uint16_t; |
| 94 | |
| 95 | typedef struct { |
| 96 | uint32_t val; |
| 97 | } __attribute__((packed)) unaligned_uint32_t; |
| 98 | |
| 99 | static inline uint16_t |
| 100 | EXTRACT_16BITS(const void *p) |
| 101 | { |
| 102 | return ((uint16_t)ntohs(((const unaligned_uint16_t *)(p))->val)); |
| 103 | } |
| 104 | |
| 105 | static inline uint32_t |
| 106 | EXTRACT_32BITS(const void *p) |
| 107 | { |
| 108 | return ((uint32_t)ntohl(((const unaligned_uint32_t *)(p))->val)); |
| 109 | } |
| 110 | |
| 111 | static inline uint64_t |
| 112 | EXTRACT_64BITS(const void *p) |
| 113 | { |
| 114 | return ((uint64_t)(((uint64_t)ntohl(((const unaligned_uint32_t *)(p) + 0)->val)) << 32 | \ |
| 115 | ((uint64_t)ntohl(((const unaligned_uint32_t *)(p) + 1)->val)) << 0)); |
| 116 | } |
| 117 | |
| 118 | #else /* have to do it a byte at a time */ |
| 119 | /* |
| 120 | * This isn't a GCC-compatible compiler, we don't have __attribute__, |
| 121 | * or we do but we don't know of any better way with this instruction |
| 122 | * set to do unaligned loads, so do unaligned loads of big-endian |
| 123 | * quantities the hard way - fetch the bytes one at a time and |
| 124 | * assemble them. |
| 125 | */ |
| 126 | #define EXTRACT_16BITS(p) \ |
| 127 | ((uint16_t)(((uint16_t)(*((const uint8_t *)(p) + 0)) << 8) | \ |
| 128 | ((uint16_t)(*((const uint8_t *)(p) + 1)) << 0))) |
| 129 | #define EXTRACT_32BITS(p) \ |
| 130 | ((uint32_t)(((uint32_t)(*((const uint8_t *)(p) + 0)) << 24) | \ |
| 131 | ((uint32_t)(*((const uint8_t *)(p) + 1)) << 16) | \ |
| 132 | ((uint32_t)(*((const uint8_t *)(p) + 2)) << 8) | \ |
| 133 | ((uint32_t)(*((const uint8_t *)(p) + 3)) << 0))) |
| 134 | #define EXTRACT_64BITS(p) \ |
| 135 | ((uint64_t)(((uint64_t)(*((const uint8_t *)(p) + 0)) << 56) | \ |
| 136 | ((uint64_t)(*((const uint8_t *)(p) + 1)) << 48) | \ |
| 137 | ((uint64_t)(*((const uint8_t *)(p) + 2)) << 40) | \ |
| 138 | ((uint64_t)(*((const uint8_t *)(p) + 3)) << 32) | \ |
| 139 | ((uint64_t)(*((const uint8_t *)(p) + 4)) << 24) | \ |
| 140 | ((uint64_t)(*((const uint8_t *)(p) + 5)) << 16) | \ |
| 141 | ((uint64_t)(*((const uint8_t *)(p) + 6)) << 8) | \ |
| 142 | ((uint64_t)(*((const uint8_t *)(p) + 7)) << 0))) |
| 143 | #endif /* must special-case unaligned accesses */ |
| 144 | #else /* LBL_ALIGN */ |
| 145 | /* |
| 146 | * The processor natively handles unaligned loads, so we can just |
| 147 | * cast the pointer and fetch through it. |
| 148 | */ |
| 149 | static inline uint16_t |
| 150 | EXTRACT_16BITS(const void *p) |
| 151 | { |
| 152 | return ((uint16_t)ntohs(*(const uint16_t *)(p))); |
| 153 | } |
| 154 | |
| 155 | static inline uint32_t |
| 156 | EXTRACT_32BITS(const void *p) |
| 157 | { |
| 158 | return ((uint32_t)ntohl(*(const uint32_t *)(p))); |
| 159 | } |
| 160 | |
| 161 | static inline uint64_t |
| 162 | EXTRACT_64BITS(const void *p) |
| 163 | { |
| 164 | return ((uint64_t)(((uint64_t)ntohl(*((const uint32_t *)(p) + 0))) << 32 | \ |
| 165 | ((uint64_t)ntohl(*((const uint32_t *)(p) + 1))) << 0)); |
| 166 | |
| 167 | } |
| 168 | |
| 169 | #endif /* LBL_ALIGN */ |
| 170 | |
| 171 | #define EXTRACT_24BITS(p) \ |
| 172 | ((uint32_t)(((uint32_t)(*((const uint8_t *)(p) + 0)) << 16) | \ |
| 173 | ((uint32_t)(*((const uint8_t *)(p) + 1)) << 8) | \ |
| 174 | ((uint32_t)(*((const uint8_t *)(p) + 2)) << 0))) |
| 175 | |
| 176 | #define EXTRACT_40BITS(p) \ |
| 177 | ((uint64_t)(((uint64_t)(*((const uint8_t *)(p) + 0)) << 32) | \ |
| 178 | ((uint64_t)(*((const uint8_t *)(p) + 1)) << 24) | \ |
| 179 | ((uint64_t)(*((const uint8_t *)(p) + 2)) << 16) | \ |
| 180 | ((uint64_t)(*((const uint8_t *)(p) + 3)) << 8) | \ |
| 181 | ((uint64_t)(*((const uint8_t *)(p) + 4)) << 0))) |
| 182 | |
| 183 | #define EXTRACT_48BITS(p) \ |
| 184 | ((uint64_t)(((uint64_t)(*((const uint8_t *)(p) + 0)) << 40) | \ |
| 185 | ((uint64_t)(*((const uint8_t *)(p) + 1)) << 32) | \ |
| 186 | ((uint64_t)(*((const uint8_t *)(p) + 2)) << 24) | \ |
| 187 | ((uint64_t)(*((const uint8_t *)(p) + 3)) << 16) | \ |
| 188 | ((uint64_t)(*((const uint8_t *)(p) + 4)) << 8) | \ |
| 189 | ((uint64_t)(*((const uint8_t *)(p) + 5)) << 0))) |
| 190 | |
| 191 | #define EXTRACT_56BITS(p) \ |
| 192 | ((uint64_t)(((uint64_t)(*((const uint8_t *)(p) + 0)) << 48) | \ |
| 193 | ((uint64_t)(*((const uint8_t *)(p) + 1)) << 40) | \ |
| 194 | ((uint64_t)(*((const uint8_t *)(p) + 2)) << 32) | \ |
| 195 | ((uint64_t)(*((const uint8_t *)(p) + 3)) << 24) | \ |
| 196 | ((uint64_t)(*((const uint8_t *)(p) + 4)) << 16) | \ |
| 197 | ((uint64_t)(*((const uint8_t *)(p) + 5)) << 8) | \ |
| 198 | ((uint64_t)(*((const uint8_t *)(p) + 6)) << 0))) |
| 199 | |
| 200 | /* |
| 201 | * Macros to extract possibly-unaligned little-endian integral values. |
| 202 | * XXX - do loads on little-endian machines that support unaligned loads? |
| 203 | */ |
| 204 | #define EXTRACT_LE_8BITS(p) (*(p)) |
| 205 | #define EXTRACT_LE_16BITS(p) \ |
| 206 | ((uint16_t)(((uint16_t)(*((const uint8_t *)(p) + 1)) << 8) | \ |
| 207 | ((uint16_t)(*((const uint8_t *)(p) + 0)) << 0))) |
| 208 | #define EXTRACT_LE_32BITS(p) \ |
| 209 | ((uint32_t)(((uint32_t)(*((const uint8_t *)(p) + 3)) << 24) | \ |
| 210 | ((uint32_t)(*((const uint8_t *)(p) + 2)) << 16) | \ |
| 211 | ((uint32_t)(*((const uint8_t *)(p) + 1)) << 8) | \ |
| 212 | ((uint32_t)(*((const uint8_t *)(p) + 0)) << 0))) |
| 213 | #define EXTRACT_LE_24BITS(p) \ |
| 214 | ((uint32_t)(((uint32_t)(*((const uint8_t *)(p) + 2)) << 16) | \ |
| 215 | ((uint32_t)(*((const uint8_t *)(p) + 1)) << 8) | \ |
| 216 | ((uint32_t)(*((const uint8_t *)(p) + 0)) << 0))) |
| 217 | #define EXTRACT_LE_64BITS(p) \ |
| 218 | ((uint64_t)(((uint64_t)(*((const uint8_t *)(p) + 7)) << 56) | \ |
| 219 | ((uint64_t)(*((const uint8_t *)(p) + 6)) << 48) | \ |
| 220 | ((uint64_t)(*((const uint8_t *)(p) + 5)) << 40) | \ |
| 221 | ((uint64_t)(*((const uint8_t *)(p) + 4)) << 32) | \ |
| 222 | ((uint64_t)(*((const uint8_t *)(p) + 3)) << 24) | \ |
| 223 | ((uint64_t)(*((const uint8_t *)(p) + 2)) << 16) | \ |
| 224 | ((uint64_t)(*((const uint8_t *)(p) + 1)) << 8) | \ |
| 225 | ((uint64_t)(*((const uint8_t *)(p) + 0)) << 0))) |