src/osbridge-crc.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  Copyright (C) 2009 Gabor Juhos <juhosg@openwrt.org>
   4  */
   5
   6 #include <byteswap.h>
   7 #include <stdio.h>
   8 #include <stdlib.h>
   9 #include <stdint.h>
  10 #include <string.h>
  11 #include <unistd.h>     /* for unlink() */
  12 #include <libgen.h>
  13 #include <getopt.h>     /* for getopt() */
  14 #include <stdarg.h>
  15 #include <errno.h>
  16 #include <sys/stat.h>
  17
  18 #if (__BYTE_ORDER == __LITTLE_ENDIAN)
  19 #  define HOST_TO_LE16(x)       (x)
  20 #  define HOST_TO_LE32(x)       (x)
  21 #  define LE16_TO_HOST(x)       (x)
  22 #  define LE32_TO_HOST(x)       (x)
  23 #else
  24 #  define HOST_TO_LE16(x)       bswap_16(x)
  25 #  define HOST_TO_LE32(x)       bswap_32(x)
  26 #  define LE16_TO_HOST(x)       bswap_16(x)
  27 #  define LE32_TO_HOST(x)       bswap_32(x)
  28 #endif
  29
  30 uint32_t crc32buf(char *buf, size_t len);
  31
  32 /*
  33  * Globals
  34  */
  35 static char *ifname;
  36 static char *progname;
  37 static char *ofname;
  38
  39 /*
  40  * Message macros
  41  */
  42 #define ERR(fmt, ...) do { \
  43         fflush(0); \
  44         fprintf(stderr, "[%s] *** error: " fmt "\n", \
  45                         progname, ## __VA_ARGS__ ); \
  46 } while (0)
  47
  48 #define ERRS(fmt, ...) do { \
  49         int save = errno; \
  50         fflush(0); \
  51         fprintf(stderr, "[%s] *** error: " fmt ": %s\n", \
  52                         progname, ## __VA_ARGS__, strerror(save)); \
  53 } while (0)
  54
  55 void usage(int status)
  56 {
  57         FILE *stream = (status != EXIT_SUCCESS) ? stderr : stdout;
  58
  59         fprintf(stream, "Usage: %s [OPTIONS...]\n", progname);
  60         fprintf(stream,
  61 "\n"
  62 "Options:\n"
  63 "  -i <file>       read input from the file <file>\n"
  64 "  -o <file>       write output to the file <file>\n"
  65 "  -h              show this screen\n"
  66         );
  67
  68         exit(status);
  69 }
  70
  71 int main(int argc, char *argv[])
  72 {
  73         int res = EXIT_FAILURE;
  74         int buflen;
  75         int err;
  76         struct stat st;
  77         char *buf;
  78         uint32_t *hdr;
  79         uint32_t crc;
  80
  81         FILE *outfile, *infile;
  82
  83         progname = basename(argv[0]);
  84
  85         while ( 1 ) {
  86                 int c;
  87
  88                 c = getopt(argc, argv, "i:o:h");
  89                 if (c == -1)
  90                         break;
  91
  92                 switch (c) {
  93                 case 'i':
  94                         ifname = optarg;
  95                         break;
  96                 case 'o':
  97                         ofname = optarg;
  98                         break;
  99                 case 'h':
 100                         usage(EXIT_SUCCESS);
 101                         break;
 102                 default:
 103                         usage(EXIT_FAILURE);
 104                         break;
 105                 }
 106         }
 107
 108         if (ifname == NULL) {
 109                 ERR("no input file specified");
 110                 goto err;
 111         }
 112
 113         if (ofname == NULL) {
 114                 ERR("no output file specified");
 115                 goto err;
 116         }
 117
 118         err = stat(ifname, &st);
 119         if (err){
 120                 ERRS("stat failed on %s", ifname);
 121                 goto err;
 122         }
 123
 124         buflen = st.st_size;
 125         buf = malloc(buflen);
 126         if (!buf) {
 127                 ERR("no memory for buffer\n");
 128                 goto err;
 129         }
 130
 131         infile = fopen(ifname, "r");
 132         if (infile == NULL) {
 133                 ERRS("could not open \"%s\" for reading", ifname);
 134                 goto err_free;
 135         }
 136
 137         errno = 0;
 138         fread(buf, buflen, 1, infile);
 139         if (errno != 0) {
 140                 ERRS("unable to read from file %s", ifname);
 141                 goto err_close_in;
 142         }
 143
 144         crc = crc32buf(buf, buflen);
 145         hdr = (uint32_t *)buf;
 146         *hdr = HOST_TO_LE32(crc);
 147
 148         outfile = fopen(ofname, "w");
 149         if (outfile == NULL) {
 150                 ERRS("could not open \"%s\" for writing", ofname);
 151                 goto err_close_in;
 152         }
 153
 154         errno = 0;
 155         fwrite(buf, buflen, 1, outfile);
 156         if (errno) {
 157                 ERRS("unable to write to file %s", ofname);
 158                 goto err_close_out;
 159         }
 160
 161         res = EXIT_SUCCESS;
 162
 163         fflush(outfile);
 164
 165  err_close_out:
 166         fclose(outfile);
 167         if (res != EXIT_SUCCESS) {
 168                 unlink(ofname);
 169         }
 170
 171  err_close_in:
 172         fclose(infile);
 173
 174  err_free:
 175         free(buf);
 176
 177  err:
 178         return res;
 179 }
 180
 181 /**********************************************************************/
 182 /* The following was grabbed and tweaked from the old snippets collection
 183  * of public domain C code. */
 184
 185 /**********************************************************************\
 186 |* Demonstration program to compute the 32-bit CRC used as the frame  *|
 187 |* check sequence in ADCCP (ANSI X3.66, also known as FIPS PUB 71     *|
 188 |* and FED-STD-1003, the U.S. versions of CCITT's X.25 link-level     *|
 189 |* protocol).  The 32-bit FCS was added via the Federal Register,     *|
 190 |* 1 June 1982, p.23798.  I presume but don't know for certain that   *|
 191 |* this polynomial is or will be included in CCITT V.41, which        *|
 192 |* defines the 16-bit CRC (often called CRC-CCITT) polynomial.  FIPS  *|
 193 |* PUB 78 says that the 32-bit FCS reduces otherwise undetected       *|
 194 |* errors by a factor of 10^-5 over 16-bit FCS.                       *|
 195 \**********************************************************************/
 196
 197 /* Copyright (C) 1986 Gary S. Brown.  You may use this program, or
 198    code or tables extracted from it, as desired without restriction.*/
 199
 200 /* First, the polynomial itself and its table of feedback terms.  The  */
 201 /* polynomial is                                                       */
 202 /* 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 */
 203 /* Note that we take it "backwards" and put the highest-order term in  */
 204 /* the lowest-order bit.  The X^32 term is "implied"; the LSB is the   */
 205 /* X^31 term, etc.  The X^0 term (usually shown as "+1") results in    */
 206 /* the MSB being 1.                                                    */
 207
 208 /* Note that the usual hardware shift register implementation, which   */
 209 /* is what we're using (we're merely optimizing it by doing eight-bit  */
 210 /* chunks at a time) shifts bits into the lowest-order term.  In our   */
 211 /* implementation, that means shifting towards the right.  Why do we   */
 212 /* do it this way?  Because the calculated CRC must be transmitted in  */
 213 /* order from highest-order term to lowest-order term.  UARTs transmit */
 214 /* characters in order from LSB to MSB.  By storing the CRC this way,  */
 215 /* we hand it to the UART in the order low-byte to high-byte; the UART */
 216 /* sends each low-bit to hight-bit; and the result is transmission bit */
 217 /* by bit from highest- to lowest-order term without requiring any bit */
 218 /* shuffling on our part.  Reception works similarly.                  */
 219
 220 /* The feedback terms table consists of 256, 32-bit entries.  Notes:   */
 221 /*                                                                     */
 222 /*  1. The table can be generated at runtime if desired; code to do so */
 223 /*     is shown later.  It might not be obvious, but the feedback      */
 224 /*     terms simply represent the results of eight shift/xor opera-    */
 225 /*     tions for all combinations of data and CRC register values.     */
 226 /*                                                                     */
 227 /*  2. The CRC accumulation logic is the same for all CRC polynomials, */
 228 /*     be they sixteen or thirty-two bits wide.  You simply choose the */
 229 /*     appropriate table.  Alternatively, because the table can be     */
 230 /*     generated at runtime, you can start by generating the table for */
 231 /*     the polynomial in question and use exactly the same "updcrc",   */
 232 /*     if your application needn't simultaneously handle two CRC       */
 233 /*     polynomials.  (Note, however, that XMODEM is strange.)          */
 234 /*                                                                     */
 235 /*  3. For 16-bit CRCs, the table entries need be only 16 bits wide;   */
 236 /*     of course, 32-bit entries work OK if the high 16 bits are zero. */
 237 /*                                                                     */
 238 /*  4. The values must be right-shifted by eight bits by the "updcrc"  */
 239 /*     logic; the shift must be unsigned (bring in zeroes).  On some   */
 240 /*     hardware you could probably optimize the shift in assembler by  */
 241 /*     using byte-swap instructions.                                   */
 242
 243 static const uint32_t crc_32_tab[] = { /* CRC polynomial 0xedb88320 */
 244 0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f,
 245 0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
 246 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91, 0x1db71064, 0x6ab020f2,
 247 0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
 248 0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9,
 249 0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
 250 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, 0x35b5a8fa, 0x42b2986c,
 251 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
 252 0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423,
 253 0xcfba9599, 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
 254 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190, 0x01db7106,
 255 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
 256 0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d,
 257 0x91646c97, 0xe6635c01, 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
 258 0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
 259 0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
 260 0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7,
 261 0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
 262 0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa,
 263 0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
 264 0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81,
 265 0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
 266 0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683, 0xe3630b12, 0x94643b84,
 267 0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
 268 0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb,
 269 0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
 270 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, 0xd6d6a3e8, 0xa1d1937e,
 271 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
 272 0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55,
 273 0x316e8eef, 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
 274 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, 0xb2bd0b28,
 275 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
 276 0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f,
 277 0x72076785, 0x05005713, 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
 278 0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242,
 279 0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
 280 0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69,
 281 0x616bffd3, 0x166ccf45, 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
 282 0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc,
 283 0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
 284 0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693,
 285 0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
 286 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
 287 };
 288
 289 #define UPDC32(octet,crc) (crc_32_tab[((crc) ^ (octet)) & 0xff] ^ ((crc) >> 8))
 290
 291 uint32_t crc32buf(char *buf, size_t len)
 292 {
 293       uint32_t crc;
 294
 295       crc = 0xFFFFFFFF;
 296
 297       for ( ; len; --len, ++buf)
 298       {
 299             crc = UPDC32(*buf, crc);
 300       }
 301
 302       return crc ^ 0xFFFFFFFF;
 303 }
 304