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mkmerakifw-old.c 9.5 KB

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  1. /*
  2. * Copyright (C) 2015 Thomas Hebb <tommyhebb@gmail.com>
  3. * Copyright (C) 2016 Christian Lamparter <chunkeey@googlemail.com>
  4. *
  5. * The format of the header this tool generates was first documented by
  6. * Chris Blake <chrisrblake93 (at) gmail.com> in a shell script of the
  7. * same purpose. I have created this reimplementation at his request. The
  8. * original script can be found at:
  9. * <https://github.com/riptidewave93/meraki-partbuilder>
  10. *
  11. * Support for the old header format, which is used by the Cisco Z1 AP
  12. * has been reverse engineered from the nandloader's nand_load_bk function.
  13. * The original code is part of Cisco's GPL code and can be found at:
  14. * <https://github.com/riptidewave93/meraki-linux>
  15. *
  16. * This program is free software; you can redistribute it and/or modify it
  17. * under the terms of the GNU General Public License version 2 as published
  18. * by the Free Software Foundation.
  19. *
  20. */
  21. #include <stdio.h>
  22. #include <stdlib.h>
  23. #include <stdbool.h>
  24. #include <string.h>
  25. #include <libgen.h>
  26. #include <endian.h>
  27. #include <getopt.h>
  28. #include <errno.h>
  29. #include <arpa/inet.h>
  30. #define PADDING_BYTE 0xff
  31. #define HDR_LENGTH 0x00000020
  32. #define HDR_OFF_MAGIC1 0
  33. #define HDR_OFF_LOAD_ADDR 4
  34. #define HDR_OFF_IMAGELEN 8
  35. #define HDR_OFF_ENTRY 12
  36. #define HDR_OFF_CHECKSUM 16
  37. #define HDR_OFF_FILLER0 20
  38. #define HDR_OFF_FILLER1 24
  39. #define HDR_OFF_FILLER2 28
  40. struct board_info {
  41. char *id;
  42. char *description;
  43. uint32_t magic;
  44. uint32_t imagelen;
  45. uint32_t load_addr;
  46. uint32_t entry;
  47. };
  48. /*
  49. * Globals
  50. */
  51. static char *progname;
  52. static bool strip_padding;
  53. static char *board_id;
  54. static const struct board_info *board;
  55. static const struct board_info boards[] = {
  56. {
  57. .id = "z1",
  58. .description = "Meraki Z1 Access Point",
  59. .magic = 0x4d495053,
  60. .imagelen = 0x007e0000,
  61. .load_addr = 0x80060000,
  62. .entry = 0x80060000
  63. }, {
  64. /* terminating entry */
  65. }
  66. };
  67. /*
  68. * Message macros
  69. */
  70. #define ERR(fmt, ...) do { \
  71. fflush(0); \
  72. fprintf(stderr, "[%s] *** error: " fmt "\n", \
  73. progname, ## __VA_ARGS__); \
  74. } while (0)
  75. #define ERRS(fmt, ...) do { \
  76. int save = errno; \
  77. fflush(0); \
  78. fprintf(stderr, "[%s] *** error: " fmt "\n", \
  79. progname, ## __VA_ARGS__, strerror(save)); \
  80. } while (0)
  81. static const struct board_info *find_board(const char *id)
  82. {
  83. const struct board_info *ret;
  84. const struct board_info *board;
  85. ret = NULL;
  86. for (board = boards; board->id != NULL; board++) {
  87. if (strcasecmp(id, board->id) == 0) {
  88. ret = board;
  89. break;
  90. }
  91. }
  92. return ret;
  93. }
  94. static void usage(int status)
  95. {
  96. FILE *stream = (status != EXIT_SUCCESS) ? stderr : stdout;
  97. const struct board_info *board;
  98. fprintf(stream, "Usage: %s [OPTIONS...]\n", progname);
  99. fprintf(stream,
  100. "\n"
  101. "Options:\n"
  102. " -B <board> create image for the board specified with <board>\n"
  103. " -i <file> read kernel image from the file <file>\n"
  104. " -o <file> write output to the file <file>\n"
  105. " -s strip padding from the end of the image\n"
  106. " -h show this screen\n"
  107. );
  108. fprintf(stream, "\nBoards:\n");
  109. for (board = boards; board->id != NULL; board++)
  110. fprintf(stream, " %-16s%s\n", board->id, board->description);
  111. exit(status);
  112. }
  113. static void writel(unsigned char *buf, size_t offset, uint32_t value)
  114. {
  115. value = htonl(value);
  116. memcpy(buf + offset, &value, sizeof(uint32_t));
  117. }
  118. static const uint32_t crc32_table[] = {
  119. 0x00000000, 0x77073096, 0xee0e612c, 0x990951ba,
  120. 0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3,
  121. 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
  122. 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91,
  123. 0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de,
  124. 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
  125. 0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec,
  126. 0x14015c4f, 0x63066cd9, 0xfa0f3d63, 0x8d080df5,
  127. 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
  128. 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b,
  129. 0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940,
  130. 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
  131. 0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116,
  132. 0x21b4f4b5, 0x56b3c423, 0xcfba9599, 0xb8bda50f,
  133. 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
  134. 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d,
  135. 0x76dc4190, 0x01db7106, 0x98d220bc, 0xefd5102a,
  136. 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
  137. 0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818,
  138. 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01,
  139. 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
  140. 0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457,
  141. 0x65b0d9c6, 0x12b7e950, 0x8bbeb8ea, 0xfcb9887c,
  142. 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
  143. 0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2,
  144. 0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb,
  145. 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
  146. 0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9,
  147. 0x5005713c, 0x270241aa, 0xbe0b1010, 0xc90c2086,
  148. 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
  149. 0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4,
  150. 0x59b33d17, 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad,
  151. 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
  152. 0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683,
  153. 0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8,
  154. 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
  155. 0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe,
  156. 0xf762575d, 0x806567cb, 0x196c3671, 0x6e6b06e7,
  157. 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
  158. 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5,
  159. 0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252,
  160. 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
  161. 0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60,
  162. 0xdf60efc3, 0xa867df55, 0x316e8eef, 0x4669be79,
  163. 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
  164. 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f,
  165. 0xc5ba3bbe, 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04,
  166. 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
  167. 0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a,
  168. 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713,
  169. 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
  170. 0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21,
  171. 0x86d3d2d4, 0xf1d4e242, 0x68ddb3f8, 0x1fda836e,
  172. 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
  173. 0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c,
  174. 0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45,
  175. 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
  176. 0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db,
  177. 0xaed16a4a, 0xd9d65adc, 0x40df0b66, 0x37d83bf0,
  178. 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
  179. 0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6,
  180. 0xbad03605, 0xcdd70693, 0x54de5729, 0x23d967bf,
  181. 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
  182. 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d,
  183. };
  184. static inline uint32_t crc32_accumulate_8(const uint32_t crc, const uint8_t ch)
  185. {
  186. return crc32_table[(crc ^ ch) & 0xff] ^ (crc >> 8);
  187. }
  188. static void crc32_csum(uint8_t *buf, const size_t len)
  189. {
  190. uint32_t crc;
  191. size_t i;
  192. crc = ~0;
  193. for (i = 0; i < len; i += 4) {
  194. crc = crc32_accumulate_8(crc, buf[i + 3]);
  195. crc = crc32_accumulate_8(crc, buf[i + 2]);
  196. crc = crc32_accumulate_8(crc, buf[i + 1]);
  197. crc = crc32_accumulate_8(crc, buf[i]);
  198. }
  199. crc = ~crc;
  200. writel(buf, HDR_OFF_CHECKSUM, crc);
  201. }
  202. static int meraki_build_hdr(const struct board_info *board, const size_t klen,
  203. FILE *out, FILE *in)
  204. {
  205. unsigned char *kernel;
  206. unsigned char *buf;
  207. size_t buflen;
  208. size_t kspace;
  209. size_t rc;
  210. buflen = board->imagelen;
  211. kspace = buflen - HDR_LENGTH;
  212. if (klen > kspace) {
  213. ERR("kernel file is too big - max size: 0x%08lX\n", kspace);
  214. return EXIT_FAILURE;
  215. }
  216. /* If requested, resize buffer to remove padding */
  217. if (strip_padding)
  218. buflen = klen + HDR_LENGTH;
  219. /* Allocate and initialize buffer for final image */
  220. buf = malloc(buflen);
  221. if (buf == NULL) {
  222. ERRS("no memory for buffer: %s\n");
  223. return EXIT_FAILURE;
  224. }
  225. memset(buf, PADDING_BYTE, buflen);
  226. /* Load kernel */
  227. kernel = buf + HDR_LENGTH;
  228. fread(kernel, klen, 1, in);
  229. /* Write magic values and filler */
  230. writel(buf, HDR_OFF_MAGIC1, board->magic);
  231. writel(buf, HDR_OFF_FILLER0, 0);
  232. writel(buf, HDR_OFF_FILLER1, 0);
  233. writel(buf, HDR_OFF_FILLER2, 0);
  234. /* Write load and kernel entry point address */
  235. writel(buf, HDR_OFF_LOAD_ADDR, board->load_addr);
  236. writel(buf, HDR_OFF_ENTRY, board->entry);
  237. /* Write header and image length */
  238. writel(buf, HDR_OFF_IMAGELEN, klen);
  239. /* this gets replaced later, after the checksum has been calculated */
  240. writel(buf, HDR_OFF_CHECKSUM, 0);
  241. /* Write checksum */
  242. crc32_csum(buf, klen + HDR_LENGTH);
  243. rc = fwrite(buf, buflen, 1, out);
  244. free(buf);
  245. return rc == 1 ? EXIT_SUCCESS : EXIT_FAILURE;
  246. }
  247. int main(int argc, char *argv[])
  248. {
  249. int ret = EXIT_FAILURE;
  250. char *ofname = NULL, *ifname = NULL;
  251. FILE *out, *in;
  252. size_t klen;
  253. progname = basename(argv[0]);
  254. while (1) {
  255. int c;
  256. c = getopt(argc, argv, "B:i:o:sh");
  257. if (c == -1)
  258. break;
  259. switch (c) {
  260. case 'B':
  261. board_id = optarg;
  262. break;
  263. case 'i':
  264. ifname = optarg;
  265. break;
  266. case 'o':
  267. ofname = optarg;
  268. break;
  269. case 's':
  270. strip_padding = true;
  271. break;
  272. case 'h':
  273. usage(EXIT_SUCCESS);
  274. break;
  275. default:
  276. usage(EXIT_FAILURE);
  277. break;
  278. }
  279. }
  280. if (board_id == NULL) {
  281. ERR("no board specified");
  282. goto err;
  283. }
  284. board = find_board(board_id);
  285. if (board == NULL) {
  286. ERR("unknown board \"%s\"", board_id);
  287. goto err;
  288. }
  289. if (ifname == NULL) {
  290. ERR("no input file specified");
  291. goto err;
  292. }
  293. if (ofname == NULL) {
  294. ERR("no output file specified");
  295. goto err;
  296. }
  297. in = fopen(ifname, "r");
  298. if (in == NULL) {
  299. ERRS("could not open \"%s\" for reading: %s", ifname);
  300. goto err;
  301. }
  302. /* Get kernel length */
  303. fseek(in, 0, SEEK_END);
  304. klen = ftell(in);
  305. rewind(in);
  306. out = fopen(ofname, "w");
  307. if (out == NULL) {
  308. ERRS("could not open \"%s\" for writing: %s", ofname);
  309. goto err_close_in;
  310. }
  311. ret = meraki_build_hdr(board, klen, out, in);
  312. fclose(out);
  313. err_close_in:
  314. fclose(in);
  315. err:
  316. return ret;
  317. }