/*
 * Copyright (C) 2004,2005 Free Software Foundation
 * 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
 */

#include <config.h>

#ifdef ENABLE_PKI

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include <gnutls/gnutls.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;

/* If how is zero then the included parameters are used.
 */
int generate_prime(int bits, int how)
{
    unsigned int i;
    int ret;
    gnutls_dh_params dh_params;
    gnutls_datum p, g;

    gnutls_dh_params_init(&dh_params);

    fprintf(stderr, "Generating DH parameters...");

    if (how!=0) {
        ret = gnutls_dh_params_generate2(dh_params, bits);
        if (ret < 0) {
	    fprintf(stderr, "Error generating parameters: %s\n",
		gnutls_strerror(ret));
	    exit(1);
        }

        ret = gnutls_dh_params_export_raw(dh_params, &p, &g, NULL);
        if (ret < 0) {
  	    fprintf(stderr, "Error exporting parameters: %s\n",
		gnutls_strerror(ret));
	    exit(1);
        }
    } else {
        if (bits <= 1024) {
            p=gnutls_srp_1024_group_prime;
            g=gnutls_srp_1024_group_generator;
        } else if (bits<=1536) {
            p=gnutls_srp_1536_group_prime;
            g=gnutls_srp_1536_group_generator;
        } else {
            p=gnutls_srp_2048_group_prime;
            g=gnutls_srp_2048_group_generator;
        }

        ret = gnutls_dh_params_import_raw(dh_params, &p, &g);
        if (ret < 0) {
  	    fprintf(stderr, "Error exporting parameters: %s\n",
		gnutls_strerror(ret));
	    exit(1);
        }
    }

    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;
}

#endif