/*
 * Copyright (C) 2001,2002,2003 Nikos Mavroyanopoulos
 *
 * This file is part of GNUTLS.
 *
 * GNUTLS 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.
 *
 * GNUTLS 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 <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <gnutls/gnutls.h>
#include "../lib/defines.h"

/* Generates Diffie Hellman parameters (a prime and a generator
 * of the group). Exports them in PKCS #3 format. Used by certtool.
 */

extern FILE* outfile;
extern FILE* infile;
extern unsigned char buffer[];
extern const int buffer_size;

static int cparams = 0;

int generate_prime(int bits)
{
	unsigned int i;
	gnutls_dh_params dh_params;
	gnutls_datum p, g;

	gnutls_dh_params_init( &dh_params);

	fprintf(stderr, "Generating DH parameters...");
	
	gnutls_dh_params_generate2( dh_params, bits);
	gnutls_dh_params_export_raw( dh_params, &p, &g, NULL);

	if (cparams) {

		fprintf( outfile, "/* generator */\n"); 
		fprintf( outfile, "\nconst uint8 g[%d] = { ", g.size);
	
		for (i=0;i<g.size;i++) {
			if (i%7==0) fprintf(outfile, "\n\t");
			fprintf(outfile, "0x%.2x", g.data[i]);
			if (i!=g.size-1) fprintf(outfile, ", ");
		}

		fprintf(outfile, "\n};\n\n");
	} else {
		fprintf( outfile, "\nGenerator: ");
	
		for (i=0;i<g.size;i++) {
			if (i!=0 && i%12==0) fprintf( outfile,"\n\t");
			else if (i!=0 && i!=g.size) fprintf( outfile, ":");

			fprintf( outfile, "%.2x", g.data[i]);
		}

		fprintf( outfile,"\n\n");
	}

	/* print prime */

	if (cparams) {
		fprintf( outfile, "/* prime - %d bits */\n", p.size*8);
		fprintf( outfile, "\nconst uint8 prime[%d] = { ", p.size);
	
		for (i=0;i<p.size;i++) {
			if (i%7==0) fprintf( outfile,"\n\t");
			fprintf( outfile, "0x%.2x", p.data[i]);
			if (i!=p.size-1) fprintf( outfile, ", ");
		}

		fprintf( outfile,"\n};\n");
	} else {
		fprintf( outfile, "Prime: ");

		for (i=0;i<p.size;i++) {
			if (i!=0 && i%12==0) fprintf( outfile,"\n\t");
			else if (i!=0 && i!=p.size) fprintf( outfile, ":");
			fprintf( outfile, "%.2x", p.data[i]);
		}

		fprintf( outfile,"\n\n");

	}

	if (!cparams) { /* generate a PKCS#3 structure */
	
		int ret;
		size_t len = buffer_size;
	
		ret = gnutls_dh_params_export_pkcs3( dh_params, GNUTLS_X509_FMT_PEM,
			buffer, &len);
	
		if (ret == 0) {
			fprintf( outfile,"\n%s", buffer);
		} else {
			fprintf(stderr, "Error: %s\n", gnutls_strerror(ret));
		}

	}

	return 0;
}