/*                                                                                 
* Copyright (C) 2004 
* "Ian (Larry) Latter" <ian dot latter at midnightcode dot org> 
* 
* This program is free software; you can redistribute it and/or modify 
* it under the terms of the GNU General Public License as published by 
* the Free Software Foundation; either version 2 of the License, or 
* (at your option) any later version. 
* 
* 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 
*/

/* 
* October 10, 2004 
* 
* This "belky" tool is a hacked addition to OpenWRT's "trx" tool  
* (as at July 29, 2004) which in itself is a hacked replacement for  
* the 'trx' utility used to create wrt54g .trx firmware files.  It 
* isn't pretty, but ... you know ... 
* 
*   -- Adapted from "trx" by Manuel Novoa III of August 2004 
* 
*/

/* linux makefile touches stdafx.h .. Visual Studio blows */
//#include "stdafx.h"

#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <stdint.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <endian.h>
#include <byteswap.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>
#define  O_BINARY 0

#if __BYTE_ORDER == __BIG_ENDIAN
#define STORE32_LE(X)                  bswap_32(X)
#elif __BYTE_ORDER == __LITTLE_ENDIAN
#define STORE32_LE(X)                  (X)
#else
#error unkown endianness!
#endif

uint32_t crc32buf(char *buf, size_t len);

/**********************************************************************/
/* Program Info */
char vernam[] = "belky";
char vernum[] = "0.3.hax";

// Need to make this a command line option someday...
//#define BELKY_MAGIC_H		0x44414F4C /* "LOAD" Used by 7230 */
#define BELKY_MAGIC_H		0x02013f00  /* Used by 7231 */
//#define BELKY_MAGIC_H		0x02012f00  /* Used by 8230 */

#define BELKY_MAGIC_F		0x5241564E	/* "NVAR" */
#define BELKY_VERS_H			0x00000800	/* Version Magic */
#define BELKY_VERS_F			0x00008000	/* Version Magic */
#define BELKY_MAX_LEN		0x3A0000

struct belky_header
{
	uint32_t magic;		/* 0  ...  3 "LOAD" */
	uint32_t len;		/* 4  ...  7  Length of file including header */
	uint32_t crc32;		/* 8  ... 11  32-bit CRC (ver to eof), LE, !bit */
	uint32_t version;	/* 12 ... 27  0x8000 (32bit LE), 0, 0, 0 */
	  uint32_t pad_0;

	  uint32_t pad_1;

	  uint32_t pad_2;

	char offset_data;	/* not a header field - sneaky data offset only */
};

struct belky_header *header;

struct belky_footer
{
	uint32_t magic;	/* 0  ...  3 "NVAR"                          */
	uint32_t len;		/* 4  ...  7  Length of footer including magic */
	uint32_t crc32;	/* 8  ... 11  32-bit CRC (ver to eof), LE */
	uint32_t version;	/* 12 ... 27  0x8000 (32bit LE), 0, 0, 0 */
	  uint32_t pad_0;

	  uint32_t pad_1;

	  uint32_t pad_2;

	char offset_data;	/* not a footer field - sneaky data 
				   offset only */
};

struct belky_footer *footer;



      /* Transient program global variables */
uint32_t config_maxlen;
char config_trx[256];
char config_output[256];
char config_userconf[256];

int allow_dumb_defaults = 1;

      /**********************************************************************/


int
input_validation(void)
{

	/* output file check */
	if (strlen(config_output) == 0)
	{
		if (allow_dumb_defaults)
		{
			strncpy(config_output, "firmware.belkin", 255);
		}
		else
		{
			printf("%s: no output file specified (try --help).\n", vernam);
			return -1;
		}
	}

	/* OpenWRT firmware file check */
	if (strlen(config_trx) == 0)
	{
		if (allow_dumb_defaults)
		{
			strncpy(config_trx, "linux.trx", 255);
		}
		else
		{
			printf("%s: no OpenWRT firmware file specified (try --help).\n", vernam);
			return -1;
		}
	}

	/* user.conf file check */
	if (strlen(config_userconf) == 0)
	{
		if (allow_dumb_defaults)
		{
			strncpy(config_userconf, "user.conf", 255);
		}
		else
		{
			printf("%s: no user.conf file specified " "(try --help).\n", vernam);
			return -1;
		}
	}

	/* maxlen check */
	if (config_maxlen > BELKY_MAX_LEN)
	{
		printf("%s: *warning* maxlen [%u] exceeds default maximum [%u]\n", vernam, config_maxlen, BELKY_MAX_LEN);
		printf("%s: Be very careful, you may overwrite NVRAM\n",
		       vernam);
	}
	else
	{
		config_maxlen = BELKY_MAX_LEN;
	}


	return 0;
}


int
read_in_data_file(char *data_file, void *buffer, int maxbytes, int type)
{
	int fd;
	int bytes;
	char filesize[3];

	bytes = 0;

	if (maxbytes < 0)
	{
		printf("%s: spare buffer space is negative -- increase maxlen (?)\n", vernam);
		return -1;
	}

	if ((fd = open(data_file, O_BINARY | O_RDONLY)) < 0)
	{
		printf("%s: unable to open file [%s] for reading.\n", vernam, data_file);
		return -1;
	}

	if (lseek(fd, 0, SEEK_SET) < 0)
	{
		printf("%s: unable to seek to start of file [%s]\n", vernam, data_file);
		return -1;
	}

	/* special work for user.conf file */
	if (type == 2)
	{
		memset(filesize, 0, 3);
		bytes = read(fd, filesize, 2);
		if (bytes < 0)
		{
			printf("%s: unable to read from user.conf file [%s].\n", vernam, data_file);
			return -1;
		}
		bytes = (uint8_t) filesize[1] * 256 + (uint8_t) filesize[0];
		if (bytes > 0)
		{
			if ((bytes - 18) <= maxbytes)
			{
				maxbytes = bytes - 18;
			}
			else
			{
				printf("%s: more data in file [%s] than space left in buffer -- increase maxlen?\n", vernam, data_file);
				return -1;
			}
		}
		else
		{
			printf("%s: unable to read file size from header of file [%s].\n", vernam, data_file);
			return -1;
		}
	}

	bytes = read(fd, buffer, maxbytes);

	close(fd);

	if (bytes < 0)
	{
		printf("%s: unable to read from file [%s].\n", vernam, data_file);
		return -1;
	}

	return bytes;
}


int
write_firmware(char *data_file, char *buffer, int maxbytes)
{
	int fd;

	if ((fd = open(data_file, O_BINARY | O_RDWR | O_CREAT | O_TRUNC,
		       S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH)) < 0)
	{
		printf("%s: unable to open firmware file [%s] for writing.\n", vernam, data_file);
		return -1;
	}

	if (write(fd, buffer, maxbytes) <= 0)
	{
		printf("%s: unable to write to firmware file [%s].\n", vernam, data_file);
		return -1;
	}

	close(fd);

	return 0;
}


int
fill_headers(uint32_t filelen, uint32_t footerlen)
{

	header->magic = STORE32_LE(BELKY_MAGIC_H);
	header->len = STORE32_LE(filelen);
	header->crc32 = crc32buf((char *)&header->version,
				 filelen
				 - offsetof(struct belky_header, version));
	header->crc32 = STORE32_LE(header->crc32);
	header->version = STORE32_LE(BELKY_VERS_H);

	footer->magic = STORE32_LE(BELKY_MAGIC_F);
	footer->len = STORE32_LE(footerlen);
	footer->version = STORE32_LE(BELKY_VERS_F);
	footer->crc32 = crc32buf((char *)&footer->version, footerlen);
	footer->crc32 = STORE32_LE(footer->crc32);

	return 0;
}


int
write_debug(char *data_file, char *buffer, int maxbytes)
{
	int fd;

	if ((fd = open(data_file, O_BINARY | O_RDWR | O_CREAT | O_TRUNC)) < 0)
	{
		printf("%s: unable to open debug file [%s] for writing.\n", vernam, data_file);
		return -1;
	}

	if (write(fd, buffer, maxbytes) <= 0)
	{
		printf("%s: unable to write to debug file [%s].\n", vernam, data_file);
		return -1;
	}

	close(fd);

	return 0;
}



int
usage(int errlvl, char *runbin)
{
	/* how many printf's must a man print out, before he is truly a 
	   man .. */
	printf("\n");

	printf("%s: Usage;\n\n", vernam);
	printf("  %s [-t {linux.trx}] [-u {user.conf}] [-o {firmware.belkin}] [-m maxlen]\n", runbin);
	printf("\n");
	printf("%s: Parameters;\n\n", vernam);
	printf("  Long       Short Args        Description\n");
	printf("  ~~~~~~~~~~ ~~~~~ ~~~~~~~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\n");
	printf("  --help     -h                Display this help screen\n");
	printf("  --maxlen   -m    {num}       Over-ride / set firmware max length to {num}\n");
	printf("  --trx      -t    {file}      Read OpenWRT TRX firmware file {file}\n");
	printf("  --output   -o    {file}      Write Belkin firmware to file {file}\n");
	printf("  --userconf -u    {file}      Read Belkin \"user.conf\" file {file}\n");
	printf("  --version  -V                Display version and exit\n");
	printf("\n");

	/* the answer, my friend, is exit number one ...                 */
	/* the answer is exit number one ..                                            */
	exit(errlvl);
}


void
parse_args(int argc, char **argv)
{
	int argn;

	/* defaults */
	config_maxlen = 0;
	memset(config_trx, 0, 256);
	memset(config_output, 0, 256);
	memset(config_userconf, 0, 256);

	argn = 1;
	while (argn < argc && argv[argn][0] == '-')
	{
		// -h, --help 
		if (strcmp(argv[argn], "-h") == 0 ||
		    strcmp(argv[argn], "--help") == 0)
		{
			usage(0, argv[0]);
		}
		// -m, --maxlen 
		else if ((strcmp(argv[argn], "-m") == 0 ||
			  strcmp(argv[argn], "--maxlen") == 0)
			 && argn + 1 < argc)
		{
			++argn;
			config_maxlen = (uint32_t) atoi(argv[argn]);
		}
		// -t, --trx 
		else if ((strcmp(argv[argn], "-t") == 0 ||
			  strcmp(argv[argn], "--trx") == 0)
			 && argn + 1 < argc)
		{
			++argn;
			strncpy(config_trx, argv[argn], 255);
		}
		// -o, --output 
		else if ((strcmp(argv[argn], "-o") == 0 ||
			  strcmp(argv[argn], "--output") == 0)
			 && argn + 1 < argc)
		{
			++argn;
			strncpy(config_output, argv[argn], 255);
		}
		// -u, --userconf 
		else if ((strcmp(argv[argn], "-u") == 0 ||
			  strcmp(argv[argn], "--userconf") == 0)
			 && argn + 1 < argc)
		{
			++argn;
			strncpy(config_userconf, argv[argn], 255);
		}
		// -V, --version 
		else if (strcmp(argv[argn], "-V") == 0 ||
			 strcmp(argv[argn], "--version") == 0)
		{
			printf("%s v%s\n", vernam, vernum);
			exit(0);
		}
		// doh
		else
		{
			printf("%s: Unrecognised command parameter [%s], exiting.\n", vernam, argv[argn]);
			usage(1, argv[0]);
		}
		++argn;
	}
	if (argn != argc)
		usage(1, argv[0]);
}




      // Evil way to make main main 
#ifdef WIN32
int
_tmain(int argc, _TCHAR * argv[])
{
#else
int
main(int argc, char **argv)
{
#endif /* win32 */

	int maxlen;
	int bytes;
	int totlen;
	int fotlen;

#if O_BINARY
	_setmode(fileno(stdin), O_BINARY);
	_setmode(fileno(stdout), O_BINARY);
#endif

	/* obtain configuration state */
	parse_args(argc, argv);

	/* input validation check */
	if (input_validation() < 0)
	{
		return -1;
	}

	/* create memory region for firmware storage */
	if ((header = (struct belky_header *)malloc(config_maxlen)) == NULL)
	{
		printf("%s: unable to malloc [%d] bytes.\n", vernam, config_maxlen);
		return -1;
	}
	memset(header, 0, config_maxlen);

	/* read in the linux.trx file */
	maxlen = config_maxlen - sizeof(struct belky_header) -
		sizeof(struct belky_footer) + (sizeof(char) * 2);
	bytes = read_in_data_file(config_trx, (void *)&header->offset_data,
				  maxlen, 1);
	if (bytes < 0)
	{
		return -1;
	}
	totlen = sizeof(struct belky_header) - sizeof(char) + bytes - 3;

	/* set the correct footer offset */
	footer = (struct belky_footer *)((char *)header + (uint32_t) totlen);

	/* read in the user.conf file */
	maxlen = config_maxlen - sizeof(struct belky_footer) +
		sizeof(char) - totlen;
	bytes = read_in_data_file(config_userconf,
				  (void *)&footer->offset_data, maxlen, 2);
	if (bytes < 0)
	{
		return -1;
	}
	totlen += sizeof(struct belky_footer) - sizeof(char) + bytes - 3;
	fotlen = sizeof(footer->version) + sizeof(footer->pad_0) +
		sizeof(footer->pad_1) + sizeof(footer->pad_2) + bytes;

	/* time to colour in the picture */
	if (fill_headers((uint32_t) totlen, (uint32_t) fotlen) < 0)
	{
		return -1;
	}

	/* write firmware to firmware.belkin file */
	maxlen = totlen;
	bytes = write_firmware(config_output, (char *)header, maxlen);
	if (bytes < 0)
	{
		return -1;
	}


	return (0);
}


      /**********************************************************************/
      /* The following was grabbed and tweaked from the old snippets collection 
       * of public domain C code. */

      /**********************************************************************\ 
      |* Demonstration program to compute the 32-bit CRC used as the frame  *| 
      |* check sequence in ADCCP (ANSI X3.66, also known as FIPS PUB 71     *| 
      |* and FED-STD-1003, the U.S. versions of CCITT's X.25 link-level     *| 
      |* protocol).  The 32-bit FCS was added via the Federal Register,     *| 
      |* 1 June 1982, p.23798.  I presume but don't know for certain that   *| 
      |* this polynomial is or will be included in CCITT V.41, which        *| 
      |* defines the 16-bit CRC (often called CRC-CCITT) polynomial.  FIPS  *| 
      |* PUB 78 says that the 32-bit FCS reduces otherwise undetected       *| 
      |* errors by a factor of 10^-5 over 16-bit FCS.                       *| 
      \**********************************************************************/

      /* Copyright (C) 1986 Gary S. Brown.  You may use this program, or 
         code or tables extracted from it, as desired without restriction. */

      /* First, the polynomial itself and its table of feedback terms.  The  */
      /* polynomial is                                                       */
      /* 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 */
      /* Note that we take it "backwards" and put the highest-order term in  */
      /* the lowest-order bit.  The X^32 term is "implied"; the LSB is the   */
      /* X^31 term, etc.  The X^0 term (usually shown as "+1") results in    */
      /* the MSB being 1.                                                    */

      /* Note that the usual hardware shift register implementation, which   */
      /* is what we're using (we're merely optimizing it by doing eight-bit  */
      /* chunks at a time) shifts bits into the lowest-order term.  In our   */
      /* implementation, that means shifting towards the right.  Why do we   */
      /* do it this way?  Because the calculated CRC must be transmitted in  */
      /* order from highest-order term to lowest-order term.  UARTs transmit */
      /* characters in order from LSB to MSB.  By storing the CRC this way,  */
      /* we hand it to the UART in the order low-byte to high-byte; the UART */
      /* sends each low-bit to hight-bit; and the result is transmission bit */
      /* by bit from highest- to lowest-order term without requiring any bit */
      /* shuffling on our part.  Reception works similarly.                  */

      /* The feedback terms table consists of 256, 32-bit entries.  Notes:   */
      /*                                                                     */
      /*  1. The table can be generated at runtime if desired; code to do so */
      /*     is shown later.  It might not be obvious, but the feedback      */
      /*     terms simply represent the results of eight shift/xor opera-    */
      /*     tions for all combinations of data and CRC register values.     */
      /*                                                                     */
      /*  2. The CRC accumulation logic is the same for all CRC polynomials, */
      /*     be they sixteen or thirty-two bits wide.  You simply choose the */
      /*     appropriate table.  Alternatively, because the table can be     */
      /*     generated at runtime, you can start by generating the table for */
      /*     the polynomial in question and use exactly the same "updcrc",   */
      /*     if your application needn't simultaneously handle two CRC       */
      /*     polynomials.  (Note, however, that XMODEM is strange.)          */
      /*                                                                     */
      /*  3. For 16-bit CRCs, the table entries need be only 16 bits wide;   */
      /*     of course, 32-bit entries work OK if the high 16 bits are zero. */
      /*                                                                     */
      /*  4. The values must be right-shifted by eight bits by the "updcrc"  */
      /*     logic; the shift must be unsigned (bring in zeroes).  On some   */
      /*     hardware you could probably optimize the shift in assembler by  */
      /*     using byte-swap instructions.                                   */

static const uint32_t crc_32_tab[] = {	/* CRC polynomial 0xedb88320 */
	0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f,
	0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
	0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91, 0x1db71064, 0x6ab020f2,
	0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
	0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9,
	0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
	0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, 0x35b5a8fa, 0x42b2986c,
	0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
	0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423,
	0xcfba9599, 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
	0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190, 0x01db7106,
	0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
	0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d,
	0x91646c97, 0xe6635c01, 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
	0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
	0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
	0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7,
	0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
	0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa,
	0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
	0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81,
	0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
	0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683, 0xe3630b12, 0x94643b84,
	0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
	0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb,
	0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
	0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, 0xd6d6a3e8, 0xa1d1937e,
	0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
	0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55,
	0x316e8eef, 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
	0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, 0xb2bd0b28,
	0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
	0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f,
	0x72076785, 0x05005713, 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
	0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242,
	0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
	0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69,
	0x616bffd3, 0x166ccf45, 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
	0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc,
	0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
	0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693,
	0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
	0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
};

#define UPDC32(octet,crc) (crc_32_tab[((crc) ^ (octet)) & 0xff] ^ ((crc) >> 8))
uint32_t
crc32buf(char *buf, size_t len)
{
	uint32_t crc;

	crc = 0xFFFFFFFF;

	for (; len; --len, ++buf)
	{
		crc = UPDC32(*buf, crc);
	}

	return crc;
}