/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
 * All rights reserved.
 *
 * This package is an SSL implementation written
 * by Eric Young (eay@cryptsoft.com).
 * The implementation was written so as to conform with Netscapes SSL.
 *
 * This library is free for commercial and non-commercial use as long as
 * the following conditions are aheared to.  The following conditions
 * apply to all code found in this distribution, be it the RC4, RSA,
 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
 * included with this distribution is covered by the same copyright terms
 * except that the holder is Tim Hudson (tjh@cryptsoft.com).
 *
 * Copyright remains Eric Young's, and as such any Copyright notices in
 * the code are not to be removed.
 * If this package is used in a product, Eric Young should be given attribution
 * as the author of the parts of the library used.
 * This can be in the form of a textual message at program startup or
 * in documentation (online or textual) provided with the package.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    "This product includes cryptographic software written by
 *     Eric Young (eay@cryptsoft.com)"
 *    The word 'cryptographic' can be left out if the rouines from the library
 *    being used are not cryptographic related :-).
 * 4. If you include any Windows specific code (or a derivative thereof) from
 *    the apps directory (application code) you must include an acknowledgement:
 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
 *
 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * The licence and distribution terms for any publically available version or
 * derivative of this code cannot be changed.  i.e. this code cannot simply be
 * copied and put under another distribution licence
 * [including the GNU Public Licence.]
 */
/* ====================================================================
 * Copyright (c) 1998-2000 The OpenSSL Project.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. All advertising materials mentioning features or use of this
 *    software must display the following acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
 *
 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
 *    endorse or promote products derived from this software without
 *    prior written permission. For written permission, please contact
 *    openssl-core@openssl.org.
 *
 * 5. Products derived from this software may not be called "OpenSSL"
 *    nor may "OpenSSL" appear in their names without prior written
 *    permission of the OpenSSL Project.
 *
 * 6. Redistributions of any form whatsoever must retain the following
 *    acknowledgment:
 *    "This product includes software developed by the OpenSSL Project
 *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
 *
 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 * ====================================================================
 *
 * This product includes cryptographic software written by Eric Young
 * (eay@cryptsoft.com).  This product includes software written by Tim
 * Hudson (tjh@cryptsoft.com).
 *
 */

#include <openssl/opensslconf.h> /* for OPENSSL_NO_DH */
#ifndef OPENSSL_NO_DH
# include <stdio.h>
# include <stdlib.h>
# include <time.h>
# include <string.h>
# include "apps.h"
# include <openssl/bio.h>
# include <openssl/err.h>
# include <openssl/bn.h>
# include <openssl/dh.h>
# include <openssl/x509.h>
# include <openssl/pem.h>

# ifndef OPENSSL_NO_DSA
#  include <openssl/dsa.h>
# endif

# define DEFBITS 2048

static int dh_cb(int p, int n, BN_GENCB *cb);

typedef enum OPTION_choice {
    OPT_ERR = -1, OPT_EOF = 0, OPT_HELP,
    OPT_INFORM, OPT_OUTFORM, OPT_IN, OPT_OUT,
    OPT_ENGINE, OPT_CHECK, OPT_TEXT, OPT_NOOUT,
    OPT_RAND, OPT_DSAPARAM, OPT_C, OPT_2, OPT_5
} OPTION_CHOICE;

OPTIONS dhparam_options[] = {
    {OPT_HELP_STR, 1, '-', "Usage: %s [flags] [numbits]\n"},
    {OPT_HELP_STR, 1, '-', "Valid options are:\n"},
    {"help", OPT_HELP, '-', "Display this summary"},
    {"in", OPT_IN, '<', "Input file"},
    {"inform", OPT_INFORM, 'F', "Input format, DER or PEM"},
    {"outform", OPT_OUTFORM, 'F', "Output format, DER or PEM"},
    {"out", OPT_OUT, '>', "Output file"},
    {"check", OPT_CHECK, '-', "Check the DH parameters"},
    {"text", OPT_TEXT, '-', "Print a text form of the DH parameters"},
    {"noout", OPT_NOOUT, '-'},
    {"rand", OPT_RAND, 's',
     "Load the file(s) into the random number generator"},
    {"C", OPT_C, '-', "Print C code"},
    {"2", OPT_2, '-', "Generate parameters using 2 as the generator value"},
    {"5", OPT_5, '-', "Generate parameters using 5 as the generator value"},
# ifndef OPENSSL_NO_DSA
    {"dsaparam", OPT_DSAPARAM, '-',
     "Read or generate DSA parameters, convert to DH"},
# endif
# ifndef OPENSSL_NO_ENGINE
    {"engine", OPT_ENGINE, 's', "Use engine e, possibly a hardware device"},
# endif
    {NULL}
};

int dhparam_main(int argc, char **argv)
{
    BIO *in = NULL, *out = NULL;
    DH *dh = NULL;
    char *infile = NULL, *outfile = NULL, *prog, *inrand = NULL;
    int dsaparam = 0, i, text = 0, C = 0, ret = 1, num = 0, g = 0;
    int informat = FORMAT_PEM, outformat = FORMAT_PEM, check = 0, noout = 0;
    OPTION_CHOICE o;

    prog = opt_init(argc, argv, dhparam_options);
    while ((o = opt_next()) != OPT_EOF) {
        switch (o) {
        case OPT_EOF:
        case OPT_ERR:
 opthelp:
            BIO_printf(bio_err, "%s: Use -help for summary.\n", prog);
            goto end;
        case OPT_HELP:
            opt_help(dhparam_options);
            ret = 0;
            goto end;
        case OPT_INFORM:
            if (!opt_format(opt_arg(), OPT_FMT_PEMDER, &informat))
                goto opthelp;
            break;
        case OPT_OUTFORM:
            if (!opt_format(opt_arg(), OPT_FMT_PEMDER, &outformat))
                goto opthelp;
            break;
        case OPT_IN:
            infile = opt_arg();
            break;
        case OPT_OUT:
            outfile = opt_arg();
            break;
        case OPT_ENGINE:
            (void)setup_engine(opt_arg(), 0);
            break;
        case OPT_CHECK:
            check = 1;
            break;
        case OPT_TEXT:
            text = 1;
            break;
        case OPT_DSAPARAM:
            dsaparam = 1;
            break;
        case OPT_C:
            C = 1;
            break;
        case OPT_2:
            g = 2;
            break;
        case OPT_5:
            g = 5;
            break;
        case OPT_NOOUT:
            noout = 1;
            break;
        case OPT_RAND:
            inrand = opt_arg();
            break;
        }
    }
    argc = opt_num_rest();
    argv = opt_rest();

    if (argv[0] && (!opt_int(argv[0], &num) || num <= 0))
        goto end;

    if (g && !num)
        num = DEFBITS;

# ifndef OPENSSL_NO_DSA
    if (dsaparam && g) {
        BIO_printf(bio_err,
                   "generator may not be chosen for DSA parameters\n");
        goto end;
    }
# endif
    /* DH parameters */
    if (num && !g)
        g = 2;

    if (num) {

        BN_GENCB *cb;
        cb = BN_GENCB_new();
        if (!cb) {
            ERR_print_errors(bio_err);
            goto end;
        }

        BN_GENCB_set(cb, dh_cb, bio_err);
        if (!app_RAND_load_file(NULL, 1) && inrand == NULL) {
            BIO_printf(bio_err,
                       "warning, not much extra random data, consider using the -rand option\n");
        }
        if (inrand != NULL)
            BIO_printf(bio_err, "%ld semi-random bytes loaded\n",
                       app_RAND_load_files(inrand));

# ifndef OPENSSL_NO_DSA
        if (dsaparam) {
            DSA *dsa = DSA_new();

            BIO_printf(bio_err,
                       "Generating DSA parameters, %d bit long prime\n", num);
            if (!dsa
                || !DSA_generate_parameters_ex(dsa, num, NULL, 0, NULL, NULL,
                                               cb)) {
                DSA_free(dsa);
                BN_GENCB_free(cb);
                ERR_print_errors(bio_err);
                goto end;
            }

            dh = DSA_dup_DH(dsa);
            DSA_free(dsa);
            if (dh == NULL) {
                BN_GENCB_free(cb);
                ERR_print_errors(bio_err);
                goto end;
            }
        } else
# endif
        {
            dh = DH_new();
            BIO_printf(bio_err,
                       "Generating DH parameters, %d bit long safe prime, generator %d\n",
                       num, g);
            BIO_printf(bio_err, "This is going to take a long time\n");
            if (!dh || !DH_generate_parameters_ex(dh, num, g, cb)) {
                BN_GENCB_free(cb);
                ERR_print_errors(bio_err);
                goto end;
            }
        }

        BN_GENCB_free(cb);
        app_RAND_write_file(NULL);
    } else {

        in = bio_open_default(infile, 'r', informat);
        if (in == NULL)
            goto end;

# ifndef OPENSSL_NO_DSA
        if (dsaparam) {
            DSA *dsa;

            if (informat == FORMAT_ASN1)
                dsa = d2i_DSAparams_bio(in, NULL);
            else                /* informat == FORMAT_PEM */
                dsa = PEM_read_bio_DSAparams(in, NULL, NULL, NULL);

            if (dsa == NULL) {
                BIO_printf(bio_err, "unable to load DSA parameters\n");
                ERR_print_errors(bio_err);
                goto end;
            }

            dh = DSA_dup_DH(dsa);
            DSA_free(dsa);
            if (dh == NULL) {
                ERR_print_errors(bio_err);
                goto end;
            }
        } else
# endif
        {
            if (informat == FORMAT_ASN1)
                dh = d2i_DHparams_bio(in, NULL);
            else                /* informat == FORMAT_PEM */
                dh = PEM_read_bio_DHparams(in, NULL, NULL, NULL);

            if (dh == NULL) {
                BIO_printf(bio_err, "unable to load DH parameters\n");
                ERR_print_errors(bio_err);
                goto end;
            }
        }

        /* dh != NULL */
    }

    out = bio_open_default(outfile, 'w', outformat);
    if (out == NULL)
        goto end;

    if (text) {
        DHparams_print(out, dh);
    }

    if (check) {
        if (!DH_check(dh, &i)) {
            ERR_print_errors(bio_err);
            goto end;
        }
        if (i & DH_CHECK_P_NOT_PRIME)
            printf("p value is not prime\n");
        if (i & DH_CHECK_P_NOT_SAFE_PRIME)
            printf("p value is not a safe prime\n");
        if (i & DH_UNABLE_TO_CHECK_GENERATOR)
            printf("unable to check the generator value\n");
        if (i & DH_NOT_SUITABLE_GENERATOR)
            printf("the g value is not a generator\n");
        if (i == 0)
            printf("DH parameters appear to be ok.\n");
    }
    if (C) {
        unsigned char *data;
        int len, bits;

        len = BN_num_bytes(dh->p);
        bits = BN_num_bits(dh->p);
        data = app_malloc(len, "print a BN");
        BIO_printf(out, "#ifndef HEADER_DH_H\n"
                        "# include <openssl/dh.h>\n"
                        "#endif\n"
                        "\n");
        BIO_printf(out, "DH *get_dh%d()\n{\n", bits);
        print_bignum_var(out, dh->p, "dhp", bits, data);
        print_bignum_var(out, dh->g, "dhg", bits, data);
        BIO_printf(out, "    DH *dh = DN_new();\n"
                        "\n"
                        "    if (dh == NULL)\n"
                        "        return NULL;\n");
        BIO_printf(out, "    dh->p = BN_bin2bn(dhp_%d, sizeof (dhp_%d), NULL);\n",
               bits, bits);
        BIO_printf(out, "    dh->g = BN_bin2bn(dhg_%d, sizeof (dhg_%d), NULL);\n",
               bits, bits);
        BIO_printf(out, "    if (!dh->p || !dh->g) {\n"
                        "        DH_free(dh);\n"
                        "        return NULL;\n"
                        "    }\n");
        if (dh->length)
            BIO_printf(out,
                        "    dh->length = %ld;\n", dh->length);
        BIO_printf(out, "    return dh;\n}\n");
        OPENSSL_free(data);
    }

    if (!noout) {
        if (outformat == FORMAT_ASN1)
            i = i2d_DHparams_bio(out, dh);
        else if (dh->q)
            i = PEM_write_bio_DHxparams(out, dh);
        else
            i = PEM_write_bio_DHparams(out, dh);
        if (!i) {
            BIO_printf(bio_err, "unable to write DH parameters\n");
            ERR_print_errors(bio_err);
            goto end;
        }
    }
    ret = 0;
 end:
    BIO_free(in);
    BIO_free_all(out);
    DH_free(dh);
    return (ret);
}

static int dh_cb(int p, int n, BN_GENCB *cb)
{
    char c = '*';

    if (p == 0)
        c = '.';
    if (p == 1)
        c = '+';
    if (p == 2)
        c = '*';
    if (p == 3)
        c = '\n';
    BIO_write(BN_GENCB_get_arg(cb), &c, 1);
    (void)BIO_flush(BN_GENCB_get_arg(cb));
    return 1;
}

#else                           /* !OPENSSL_NO_DH */

# if PEDANTIC
static void *dummy = &dummy;
# endif

#endif