/*
 * spw303v.c - partially based on OpenWrt's imagetag.c and addpattern.c
 *
 * Copyright (C) 2011  Jonas Gorski <jonas.gorski@gmail.com>
 *
 * 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
 */

#include <arpa/inet.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include <unistd.h>
#include <sys/stat.h>

#define IMAGE_LEN 10                   /* Length of Length Field */
#define ADDRESS_LEN 12                 /* Length of Address field */
#define TAGID_LEN  6                   /* Length of tag ID */
#define TAGINFO_LEN 20                 /* Length of vendor information field in tag */
#define TAGVER_LEN 4                   /* Length of Tag Version */
#define TAGLAYOUT_LEN 4                /* Length of FlashLayoutVer */


struct spw303v_tag
{
    unsigned char tagVersion[4];       // tag version.  Will be 2 here.
    unsigned char signiture_1[20];         		 // text line for company info
    unsigned char signiture_2[14];        		// additional info (can be version number)
    unsigned char chipId[6];			 		// chip id
    unsigned char boardId[16];        		 	// board id
    unsigned char bigEndian[2];           		// if = 1 - big, = 0 - little endia of the host
    unsigned char totalImageLen[IMAGE_LEN];      // the sum of all the following length
    unsigned char cfeAddress[ADDRESS_LEN];       // if non zero, cfe starting address
    unsigned char cfeLen[IMAGE_LEN];             // if non zero, cfe size in clear ASCII text.
    unsigned char rootfsAddress[ADDRESS_LEN];    // if non zero, filesystem starting address
    unsigned char rootfsLen[IMAGE_LEN];          // if non zero, filesystem size in clear ASCII text.
    unsigned char kernelAddress[ADDRESS_LEN];    // if non zero, kernel starting address
    unsigned char kernelLen[IMAGE_LEN];          // if non zero, kernel size in clear ASCII text.

	unsigned char certf1Address[ADDRESS_LEN];
	unsigned char certf1Len[6];
	unsigned char certf2Address[ADDRESS_LEN];
	unsigned char certf2Len[6];
	unsigned char certf3Address[ADDRESS_LEN];
	unsigned char certf3Len[6];
	unsigned char httpsFileSize[4];
	unsigned char tr64FileSize[4];
	unsigned char tr69FileSize[4];
	unsigned char filesmap[4];

    unsigned char imageSequence[4];     			// incrments everytime an image is flashed
    unsigned char reserved[4];					    // reserved for later use
    unsigned char imageCRC[4];                      // 216-219: CRC32 of images
    unsigned char reserved2[16];                    // 220-235: Unused at present
    unsigned char headerCRC[4];                     // 236-239: CRC32 of header excluding tagVersion
    unsigned char reserved3[16];                    // 240-255: Unused at present
};

static uint32_t crc32tab[256] = {
	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 IMAGETAG_CRC_START			0xFFFFFFFF

#define IMAGETAG_MAGIC1_TCOM		"AAAAAAAA Corporatio"

static char fake_data[] = {
        0x18, 0x21, 0x21, 0x18, 0x21, 0x21, 0x21, 0x21, 0x21, 0x21, 0x21 ,0x18,
        0x21, 0x24, 0x21, 0x1b, 0x18, 0x18, 0x24, 0x24, 0x18, 0x21, 0x21, 0x21,
        0x21, 0x21, 0x21, 0x21, 0x1b, 0x18, 0x18, 0x24, 0x24, 0x21, 0x21, 0x21,
        0x21, 0x21, 0x21, 0x21, 0x18, 0x21, 0x21, 0x21, 0x21, 0x21, 0x21, 0x18,
        0x21, 0x21, 0x21, 0x21, 0x21, 0x21, 0x21, 0x21, 0x21, 0x18, 0x21, 0x21,
        0x21, 0x21, 0x21, 0x21,
};


uint32_t crc32(uint32_t crc, uint8_t *data, size_t len)
{
	while (len--)
		crc = (crc >> 8) ^ crc32tab[(crc ^ *data++) & 0xFF];

	return crc;
}

void fix_header(void *buf)
{
	struct spw303v_tag *tag = buf;
	uint32_t crc;
	/* Replace signature with custom t-com one */
	memset(tag->signiture_1, 0, 20);
	memcpy(tag->signiture_1, IMAGETAG_MAGIC1_TCOM, strlen(IMAGETAG_MAGIC1_TCOM));

	/* Clear cert fields to remove information_* data */
	memset(tag->certf1Address, 0, 74);

	/* replace image crc with modified one */
	crc = ntohl(*((uint32_t *)&tag->imageCRC));

	crc = htonl(crc32(crc, fake_data, 64));

	memcpy(tag->imageCRC, &crc, 4);

	/* Update tag crc */
	crc = htonl(crc32(IMAGETAG_CRC_START, buf, 236));
	memcpy(tag->headerCRC, &crc, 4);
}



void usage(void) __attribute__ (( __noreturn__ ));

void usage(void)
{
	fprintf(stderr, "Usage: spw303v [-i <inputfile>] [-o <outputfile>]\n");
	exit(EXIT_FAILURE);
}


int main(int argc, char **argv)
{
	char buf[1024];	/* keep this at 1k or adjust garbage calc below */
	FILE *in = stdin;
	FILE *out = stdout;
	char *ifn = NULL;
	char *ofn = NULL;
	int c;
	int v0, v1, v2;
	size_t n;
	int first_block = 1;

	uint32_t image_crc = IMAGETAG_CRC_START;

	while ((c = getopt(argc, argv, "i:o:h")) != -1) {
		switch (c) {
			case 'i':
				ifn = optarg;
				break;
			case 'o':
				ofn = optarg;
				break;
			case 'h':
			default:
				usage();
		}
	}

	if (optind != argc || optind == 1) {
		fprintf(stderr, "illegal arg \"%s\"\n", argv[optind]);
		usage();
	}

	if (ifn && !(in = fopen(ifn, "r"))) {
		fprintf(stderr, "can not open \"%s\" for reading\n", ifn);
		usage();
	}

	if (ofn && !(out = fopen(ofn, "w"))) {
		fprintf(stderr, "can not open \"%s\" for writing\n", ofn);
		usage();
	}



	while ((n = fread(buf, 1, sizeof(buf), in)) > 0) {
		if (n < sizeof(buf)) {
			if (ferror(in)) {
			FREAD_ERROR:
				fprintf(stderr, "fread error\n");
				return EXIT_FAILURE;
			}
		}

		if (first_block && n >= 256) {
			fix_header(buf);
			first_block = 0;
		}

		image_crc = crc32(image_crc, buf, n);

		if (!fwrite(buf, n, 1, out)) {
		FWRITE_ERROR:
			fprintf(stderr, "fwrite error\n");
			return EXIT_FAILURE;
		}
	}

	if (ferror(in)) {
		goto FREAD_ERROR;
	}

	if (fflush(out)) {
		goto FWRITE_ERROR;
	}

	fclose(in);
	fclose(out);

	return EXIT_SUCCESS;
}
