src/osbridge-crc.c

   1 /*
   2  *  Copyright (C) 2009 Gabor Juhos <juhosg@openwrt.org>
   3  *
   4  *  This program is free software; you can redistribute it and/or modify it
   5  *  under the terms of the GNU General Public License version 2 as published
   6  *  by the Free Software Foundation.
   7  *
   8  */
   9
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <stdint.h>
  13 #include <string.h>
  14 #include <unistd.h>     /* for unlink() */
  15 #include <libgen.h>
  16 #include <getopt.h>     /* for getopt() */
  17 #include <stdarg.h>
  18 #include <errno.h>
  19 #include <sys/stat.h>
  20
  21 #if (__BYTE_ORDER == __LITTLE_ENDIAN)
  22 #  define HOST_TO_LE16(x)       (x)
  23 #  define HOST_TO_LE32(x)       (x)
  24 #  define LE16_TO_HOST(x)       (x)
  25 #  define LE32_TO_HOST(x)       (x)
  26 #else
  27 #  define HOST_TO_LE16(x)       bswap_16(x)
  28 #  define HOST_TO_LE32(x)       bswap_32(x)
  29 #  define LE16_TO_HOST(x)       bswap_16(x)
  30 #  define LE32_TO_HOST(x)       bswap_32(x)
  31 #endif
  32
  33 uint32_t crc32buf(char *buf, size_t len);
  34
  35 /*
  36  * Globals
  37  */
  38 static char *ifname;
  39 static char *progname;
  40 static char *ofname;
  41
  42 /*
  43  * Message macros
  44  */
  45 #define ERR(fmt, ...) do { \
  46         fflush(0); \
  47         fprintf(stderr, "[%s] *** error: " fmt "\n", \
  48                         progname, ## __VA_ARGS__ ); \
  49 } while (0)
  50
  51 #define ERRS(fmt, ...) do { \
  52         int save = errno; \
  53         fflush(0); \
  54         fprintf(stderr, "[%s] *** error: " fmt ": %s\n", \
  55                         progname, ## __VA_ARGS__, strerror(save)); \
  56 } while (0)
  57
  58 void usage(int status)
  59 {
  60         FILE *stream = (status != EXIT_SUCCESS) ? stderr : stdout;
  61
  62         fprintf(stream, "Usage: %s [OPTIONS...]\n", progname);
  63         fprintf(stream,
  64 "\n"
  65 "Options:\n"
  66 "  -i <file>       read input from the file <file>\n"
  67 "  -o <file>       write output to the file <file>\n"
  68 "  -h              show this screen\n"
  69         );
  70
  71         exit(status);
  72 }
  73
  74 int main(int argc, char *argv[])
  75 {
  76         int res = EXIT_FAILURE;
  77         int buflen;
  78         int err;
  79         struct stat st;
  80         char *buf;
  81         uint32_t *hdr;
  82         uint32_t crc;
  83
  84         FILE *outfile, *infile;
  85
  86         progname = basename(argv[0]);
  87
  88         while ( 1 ) {
  89                 int c;
  90
  91                 c = getopt(argc, argv, "i:o:h");
  92                 if (c == -1)
  93                         break;
  94
  95                 switch (c) {
  96                 case 'i':
  97                         ifname = optarg;
  98                         break;
  99                 case 'o':
 100                         ofname = optarg;
 101                         break;
 102                 case 'h':
 103                         usage(EXIT_SUCCESS);
 104                         break;
 105                 default:
 106                         usage(EXIT_FAILURE);
 107                         break;
 108                 }
 109         }
 110
 111         if (ifname == NULL) {
 112                 ERR("no input file specified");
 113                 goto err;
 114         }
 115
 116         if (ofname == NULL) {
 117                 ERR("no output file specified");
 118                 goto err;
 119         }
 120
 121         err = stat(ifname, &st);
 122         if (err){
 123                 ERRS("stat failed on %s", ifname);
 124                 goto err;
 125         }
 126
 127         buflen = st.st_size;
 128         buf = malloc(buflen);
 129         if (!buf) {
 130                 ERR("no memory for buffer\n");
 131                 goto err;
 132         }
 133
 134         infile = fopen(ifname, "r");
 135         if (infile == NULL) {
 136                 ERRS("could not open \"%s\" for reading", ifname);
 137                 goto err_free;
 138         }
 139
 140         errno = 0;
 141         fread(buf, buflen, 1, infile);
 142         if (errno != 0) {
 143                 ERRS("unable to read from file %s", ifname);
 144                 goto err_close_in;
 145         }
 146
 147         crc = crc32buf(buf, buflen);
 148         hdr = (uint32_t *)buf;
 149         *hdr = HOST_TO_LE32(crc);
 150
 151         outfile = fopen(ofname, "w");
 152         if (outfile == NULL) {
 153                 ERRS("could not open \"%s\" for writing", ofname);
 154                 goto err_close_in;
 155         }
 156
 157         errno = 0;
 158         fwrite(buf, buflen, 1, outfile);
 159         if (errno) {
 160                 ERRS("unable to write to file %s", ofname);
 161                 goto err_close_out;
 162         }
 163
 164         res = EXIT_SUCCESS;
 165
 166         fflush(outfile);
 167
 168  err_close_out:
 169         fclose(outfile);
 170         if (res != EXIT_SUCCESS) {
 171                 unlink(ofname);
 172         }
 173
 174  err_close_in:
 175         fclose(infile);
 176
 177  err_free:
 178         free(buf);
 179
 180  err:
 181         return res;
 182 }
 183
 184 /**********************************************************************/
 185 /* The following was grabbed and tweaked from the old snippets collection
 186  * of public domain C code. */
 187
 188 /**********************************************************************\
 189 |* Demonstration program to compute the 32-bit CRC used as the frame  *|
 190 |* check sequence in ADCCP (ANSI X3.66, also known as FIPS PUB 71     *|
 191 |* and FED-STD-1003, the U.S. versions of CCITT's X.25 link-level     *|
 192 |* protocol).  The 32-bit FCS was added via the Federal Register,     *|
 193 |* 1 June 1982, p.23798.  I presume but don't know for certain that   *|
 194 |* this polynomial is or will be included in CCITT V.41, which        *|
 195 |* defines the 16-bit CRC (often called CRC-CCITT) polynomial.  FIPS  *|
 196 |* PUB 78 says that the 32-bit FCS reduces otherwise undetected       *|
 197 |* errors by a factor of 10^-5 over 16-bit FCS.                       *|
 198 \**********************************************************************/
 199
 200 /* Copyright (C) 1986 Gary S. Brown.  You may use this program, or
 201    code or tables extracted from it, as desired without restriction.*/
 202
 203 /* First, the polynomial itself and its table of feedback terms.  The  */
 204 /* polynomial is                                                       */
 205 /* X^32+X^26+X^23+X^22+X^16+X^12+X^11+X^10+X^8+X^7+X^5+X^4+X^2+X^1+X^0 */
 206 /* Note that we take it "backwards" and put the highest-order term in  */
 207 /* the lowest-order bit.  The X^32 term is "implied"; the LSB is the   */
 208 /* X^31 term, etc.  The X^0 term (usually shown as "+1") results in    */
 209 /* the MSB being 1.                                                    */
 210
 211 /* Note that the usual hardware shift register implementation, which   */
 212 /* is what we're using (we're merely optimizing it by doing eight-bit  */
 213 /* chunks at a time) shifts bits into the lowest-order term.  In our   */
 214 /* implementation, that means shifting towards the right.  Why do we   */
 215 /* do it this way?  Because the calculated CRC must be transmitted in  */
 216 /* order from highest-order term to lowest-order term.  UARTs transmit */
 217 /* characters in order from LSB to MSB.  By storing the CRC this way,  */
 218 /* we hand it to the UART in the order low-byte to high-byte; the UART */
 219 /* sends each low-bit to hight-bit; and the result is transmission bit */
 220 /* by bit from highest- to lowest-order term without requiring any bit */
 221 /* shuffling on our part.  Reception works similarly.                  */
 222
 223 /* The feedback terms table consists of 256, 32-bit entries.  Notes:   */
 224 /*                                                                     */
 225 /*  1. The table can be generated at runtime if desired; code to do so */
 226 /*     is shown later.  It might not be obvious, but the feedback      */
 227 /*     terms simply represent the results of eight shift/xor opera-    */
 228 /*     tions for all combinations of data and CRC register values.     */
 229 /*                                                                     */
 230 /*  2. The CRC accumulation logic is the same for all CRC polynomials, */
 231 /*     be they sixteen or thirty-two bits wide.  You simply choose the */
 232 /*     appropriate table.  Alternatively, because the table can be     */
 233 /*     generated at runtime, you can start by generating the table for */
 234 /*     the polynomial in question and use exactly the same "updcrc",   */
 235 /*     if your application needn't simultaneously handle two CRC       */
 236 /*     polynomials.  (Note, however, that XMODEM is strange.)          */
 237 /*                                                                     */
 238 /*  3. For 16-bit CRCs, the table entries need be only 16 bits wide;   */
 239 /*     of course, 32-bit entries work OK if the high 16 bits are zero. */
 240 /*                                                                     */
 241 /*  4. The values must be right-shifted by eight bits by the "updcrc"  */
 242 /*     logic; the shift must be unsigned (bring in zeroes).  On some   */
 243 /*     hardware you could probably optimize the shift in assembler by  */
 244 /*     using byte-swap instructions.                                   */
 245
 246 static const uint32_t crc_32_tab[] = { /* CRC polynomial 0xedb88320 */
 247 0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f,
 248 0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
 249 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91, 0x1db71064, 0x6ab020f2,
 250 0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
 251 0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9,
 252 0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
 253 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, 0x35b5a8fa, 0x42b2986c,
 254 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
 255 0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423,
 256 0xcfba9599, 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
 257 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190, 0x01db7106,
 258 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
 259 0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d,
 260 0x91646c97, 0xe6635c01, 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
 261 0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
 262 0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
 263 0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7,
 264 0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
 265 0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa,
 266 0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
 267 0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81,
 268 0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
 269 0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683, 0xe3630b12, 0x94643b84,
 270 0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
 271 0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb,
 272 0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
 273 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, 0xd6d6a3e8, 0xa1d1937e,
 274 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
 275 0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55,
 276 0x316e8eef, 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
 277 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, 0xb2bd0b28,
 278 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
 279 0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f,
 280 0x72076785, 0x05005713, 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
 281 0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242,
 282 0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
 283 0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69,
 284 0x616bffd3, 0x166ccf45, 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
 285 0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc,
 286 0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
 287 0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693,
 288 0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
 289 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
 290 };
 291
 292 #define UPDC32(octet,crc) (crc_32_tab[((crc) ^ (octet)) & 0xff] ^ ((crc) >> 8))
 293
 294 uint32_t crc32buf(char *buf, size_t len)
 295 {
 296       uint32_t crc;
 297
 298       crc = 0xFFFFFFFF;
 299
 300       for ( ; len; --len, ++buf)
 301       {
 302             crc = UPDC32(*buf, crc);
 303       }
 304
 305       return crc ^ 0xFFFFFFFF;
 306 }
 307