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Diffstat (limited to 'tools/firmware-utils/src/wndr3700.c')
| -rw-r--r-- | tools/firmware-utils/src/wndr3700.c | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/tools/firmware-utils/src/wndr3700.c b/tools/firmware-utils/src/wndr3700.c new file mode 100644 index 000000000..97b5f1d45 --- /dev/null +++ b/tools/firmware-utils/src/wndr3700.c @@ -0,0 +1,150 @@ +/* + * wndr3700.c - partially based on OpenWrt's add_header.c + * + * Copyright (C) 2009 Anael Orlinski <naouel@naouel.org> + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License, + * version 2 as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + */ + +/* + * The add_header utility used by various vendors preprends the buf + * image with a header containing a CRC32 value which is generated for the + * model id + reserved space for CRC32 + buf, then replaces the reserved + * area with the actual CRC32. This replacement tool mimics this behavior. + */ + +#include <stdio.h> +#include <stdlib.h> +#include <stddef.h> +#include <unistd.h> +#include <errno.h> +#include <fcntl.h> +#include <sys/mman.h> +#include <string.h> +#include <netinet/in.h> +#include <inttypes.h> + +#define BPB 8 /* bits/byte */ + +#define WNDR3700_MAGIC_LEN 4 + +static uint32_t crc32[1<<BPB]; +static char *magic = "3700"; + +static void init_crc32() +{ + const uint32_t poly = ntohl(0x2083b8ed); + int n; + + for (n = 0; n < 1<<BPB; n++) { + uint32_t crc = n; + int bit; + + for (bit = 0; bit < BPB; bit++) + crc = (crc & 1) ? (poly ^ (crc >> 1)) : (crc >> 1); + crc32[n] = crc; + } +} + +static uint32_t crc32buf(unsigned char *buf, size_t len) +{ + uint32_t crc = 0xFFFFFFFF; + + for (; len; len--, buf++) + crc = crc32[(uint8_t)crc ^ *buf] ^ (crc >> BPB); + return ~crc; +} + +struct header { + unsigned char magic[WNDR3700_MAGIC_LEN]; + uint32_t crc; + unsigned char stuff[56]; +}; + +static void usage(const char *) __attribute__ (( __noreturn__ )); + +static void usage(const char *mess) +{ + fprintf(stderr, "Error: %s\n", mess); + fprintf(stderr, "Usage: wndr3700 input_file output_file [magic]\n"); + fprintf(stderr, "\n"); + exit(1); +} + +int main(int argc, char **argv) +{ + off_t len; // of original buf + off_t buflen; // of the output file + int fd; + void *input_file; // pointer to the input file (mmmapped) + struct header header; + unsigned char *buf; // pointer to prefix + copy of original buf + + // verify parameters + + if (argc < 3) + usage("wrong number of arguments"); + + if (argc > 3) + magic = argv[3]; + + if (strlen(magic) != WNDR3700_MAGIC_LEN) { + fprintf(stderr, "Invalid magic: '%s'\n", magic); + exit(1); + } + + // mmap input_file + if ((fd = open(argv[1], O_RDONLY)) < 0 + || (len = lseek(fd, 0, SEEK_END)) < 0 + || (input_file = mmap(0, len, PROT_READ, MAP_SHARED, fd, 0)) == (void *) (-1) + || close(fd) < 0) + { + fprintf(stderr, "Error loading file %s: %s\n", argv[1], strerror(errno)); + exit(1); + } + + buflen = len; + + init_crc32(); + + // preload header + memcpy(&header, input_file, sizeof(header)); + + memcpy(header.magic, magic, WNDR3700_MAGIC_LEN); + header.crc = 0; + + // create a firmware image in memory and copy the input_file to it + buf = malloc(buflen); + memcpy(buf, input_file, len); + + // CRC of temporary header + header.crc = htonl(crc32buf((unsigned char*)&header, sizeof(header))); + + memcpy(buf, &header, sizeof(header)); + + // write the buf + if ((fd = open(argv[2], O_CREAT|O_WRONLY|O_TRUNC,0644)) < 0 + || write(fd, buf, buflen) != buflen + || close(fd) < 0) + { + fprintf(stderr, "Error storing file %s: %s\n", argv[2], strerror(errno)); + exit(2); + } + + free(buf); + + munmap(input_file,len); + + return 0; +} |