/*
 *  Simple DTLS server demonstration program
 *
 *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
 *  Copyright 2019 NXP
 *  SPDX-License-Identifier: Apache-2.0
 *
 *  Licensed under the Apache License, Version 2.0 (the "License"); you may
 *  not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *  http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *  This file is part of mbed TLS (https://tls.mbed.org)
 */

#if !defined(MBEDTLS_CONFIG_FILE)
#include "mbedtls/config.h"
#else
#include MBEDTLS_CONFIG_FILE
#endif

#if defined(MBEDTLS_PLATFORM_C)
#include "mbedtls/platform.h"
#else
#include <stdio.h>
#define mbedtls_printf printf
#define mbedtls_fprintf fprintf
#define mbedtls_time_t time_t
#endif

#if !defined(MBEDTLS_SSL_SRV_C) || !defined(MBEDTLS_SSL_PROTO_DTLS) || !defined(MBEDTLS_SSL_COOKIE_C) || \
    !defined(MBEDTLS_NET_C) || !defined(MBEDTLS_ENTROPY_C) || !defined(MBEDTLS_CTR_DRBG_C) ||            \
    !defined(MBEDTLS_X509_CRT_PARSE_C) || !defined(MBEDTLS_RSA_C) || !defined(MBEDTLS_CERTS_C) ||        \
    !defined(MBEDTLS_PEM_PARSE_C) || !defined(MBEDTLS_TIMING_C)

int main(void)
{
    printf(
        "MBEDTLS_SSL_SRV_C and/or MBEDTLS_SSL_PROTO_DTLS and/or "
        "MBEDTLS_SSL_COOKIE_C and/or MBEDTLS_NET_C and/or "
        "MBEDTLS_ENTROPY_C and/or MBEDTLS_CTR_DRBG_C and/or "
        "MBEDTLS_X509_CRT_PARSE_C and/or MBEDTLS_RSA_C and/or "
        "MBEDTLS_CERTS_C and/or MBEDTLS_PEM_PARSE_C and/or "
        "MBEDTLS_TIMING_C not defined.\n");
    return (0);
}
#else

#if defined(_WIN32)
#include <windows.h>
#endif

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "mbedtls/certs.h"
#include "mbedtls/ctr_drbg.h"
#include "mbedtls/debug.h"
#include "mbedtls/entropy.h"
#include "mbedtls/error.h"
#include "mbedtls/net_sockets.h"
#include "mbedtls/ssl.h"
#include "mbedtls/ssl_cookie.h"
#include "mbedtls/timing.h"
#include "mbedtls/x509.h"

#if defined(MBEDTLS_SSL_CACHE_C)
#include "mbedtls/ssl_cache.h"
#endif

#define READ_TIMEOUT_MS 10000 /* 5 seconds */

#define DFL_DEBUG_LEVEL 0
#define DFL_CRT_FILE ""
#define DFL_KEY_FILE ""
#define DFL_CA_FILE ""
#define DFL_MIN_VERSION -1
#define DFL_MAJ_VERSION -1

#if defined(MBEDTLS_X509_CRT_PARSE_C)
#if defined(MBEDTLS_FS_IO)
#define USAGE_IO                                                               \
    "    ca_file=%%s          The single file containing the top-level CA(s) " \
    "you fully trust\n"                                                        \
    "                        default: \"\" (pre-loaded)\n"
#else
#define USAGE_IO "    No file operations available (MBEDTLS_FS_IO not defined)\n"
#endif /* MBEDTLS_FS_IO */
#else
#define USAGE_IO ""
#endif /* MBEDTLS_X509_CRT_PARSE_C */

#define USAGE "    debug_level=%%d      default: 0 (disabled)\n" USAGE_IO

/*
 * global options
 */
struct options
{
    int debug_level;      /* level of debugging                       */
    const char *crt_file; /* the file with the server certificate     */
    const char *key_file; /* the file with the server key             */
    const char *ca_file;  /* the file with the server key             */
    int min_version;      /* minimum protocol version accepted        */
    int max_version;      /* minimum protocol version accepted        */
} opt;

static void my_debug(void *ctx, int level, const char *file, int line, const char *str)
{
    ((void)level);

    mbedtls_fprintf((FILE *)ctx, "%s:%04d: %s", file, line, str);
    fflush((FILE *)ctx);
}

int main(int argc, char *argv[])
{
    int ret = 0, len, i;
    mbedtls_net_context listen_fd, client_fd;
    unsigned char buf[1024];
    const char *pers            = "dtls_server";
    unsigned char client_ip[16] = {0};
    size_t cliip_len;
    mbedtls_ssl_cookie_ctx cookie_ctx;

    mbedtls_entropy_context entropy;
    mbedtls_ctr_drbg_context ctr_drbg;
    mbedtls_ssl_context ssl;
    mbedtls_ssl_config conf;
    mbedtls_x509_crt srvcert;
    mbedtls_x509_crt cacert;
    mbedtls_pk_context pkey;
    mbedtls_timing_delay_context timer;
#if defined(MBEDTLS_SSL_CACHE_C)
    mbedtls_ssl_cache_context cache;
#endif

    char *p, *q;

    mbedtls_net_init(&listen_fd);
    mbedtls_net_init(&client_fd);
    mbedtls_ssl_init(&ssl);
    mbedtls_ssl_config_init(&conf);
    mbedtls_ssl_cookie_init(&cookie_ctx);
#if defined(MBEDTLS_SSL_CACHE_C)
    mbedtls_ssl_cache_init(&cache);
#endif
    mbedtls_x509_crt_init(&srvcert);
    mbedtls_x509_crt_init(&cacert);
    mbedtls_pk_init(&pkey);
    mbedtls_entropy_init(&entropy);
    mbedtls_ctr_drbg_init(&ctr_drbg);

    if (argc == 1) {
    usage:
        if (ret == 0)
            ret = 1;

        mbedtls_printf(USAGE_IO);

        mbedtls_printf("\n");
        goto exit;
    }

    opt.debug_level = DFL_DEBUG_LEVEL;
    opt.crt_file    = DFL_CRT_FILE;
    opt.key_file    = DFL_KEY_FILE;
    opt.ca_file     = DFL_CA_FILE;
    opt.min_version = MBEDTLS_SSL_MINOR_VERSION_3;
    opt.max_version = MBEDTLS_SSL_MAJOR_VERSION_3;

    for (i = 1; i < argc; i++) {
        p = argv[i];
        if ((q = strchr(p, '=')) == NULL)
            goto usage;
        *q++ = '\0';

        if (strcmp(p, "debug_level") == 0) {
            opt.debug_level = atoi(q);
            if (opt.debug_level < 0 || opt.debug_level > 65535)
                goto usage;
        }
        else if (strcmp(p, "crt_file") == 0)
            opt.crt_file = q;
        else if (strcmp(p, "key_file") == 0)
            opt.key_file = q;
        else if (strcmp(p, "ca_file") == 0)
            opt.ca_file = q;
        else
            continue;
    }

#if defined(MBEDTLS_DEBUG_C)
    mbedtls_debug_set_threshold(opt.debug_level);
#endif

    /*
     * 1. Load the certificates and private RSA key
     */
    printf("\n  . Loading the server cert. and key...");
    fflush(stdout);

    /*
     * This demonstration program uses embedded test certificates.
     * Instead, you may want to use mbedtls_x509_crt_parse_file() to read the
     * server and CA certificates, as well as mbedtls_pk_parse_keyfile().
     */

/*Server-Certificate load Start*/
#if defined(MBEDTLS_FS_IO)

    if (strlen(opt.crt_file)) {
        if (strcmp(opt.crt_file, "none") == 0)
            ret = 0;
        else {
            ret = mbedtls_x509_crt_parse_file(&srvcert, opt.crt_file);
            if (ret != 0) {
                printf(" failed\n  !  mbedtls_x509_crt_parse returned %d\n\n", ret);
                goto exit;
            }
        }
    }
    else
#endif
#if defined(MBEDTLS_CERTS_C)
    {
        ret = mbedtls_x509_crt_parse(&srvcert, (const unsigned char *)mbedtls_test_srv_crt, mbedtls_test_srv_crt_len);
        if (ret != 0) {
            printf(" failed\n  !  mbedtls_x509_crt_parse returned %d\n\n", ret);
            goto exit;
        }
    }
#else
    {
        ret = 1;
        mbedtls_printf("MBEDTLS_CERTS_C not defined.");
    }
#endif

/*Server-Certificate load end*/

/*Server-key load start*/
#if defined(MBEDTLS_FS_IO)

    if (strlen(opt.key_file)) {
        if (strcmp(opt.key_file, "none") == 0)
            ret = 0;
        else {
            ret = mbedtls_pk_parse_keyfile(&pkey, opt.key_file, NULL);
            if (ret != 0) {
                printf(" failed\n  !  mbedtls_pk_parse_key returned %d\n\n", ret);
                goto exit;
            }
        }
    }
    else
#endif
#if defined(MBEDTLS_CERTS_C)
    {

        ret =
            mbedtls_pk_parse_key(&pkey, (const unsigned char *)mbedtls_test_srv_key, mbedtls_test_srv_key_len, NULL, 0);
        if (ret != 0) {
            printf(" failed\n  !  mbedtls_pk_parse_key returned %d\n\n", ret);
            goto exit;
        }
    }
#else
    {
        ret = 1;
        mbedtls_printf("MBEDTLS_CERTS_C not defined.");
    }
#endif
/*Server-key load end*/

/*Load CA Certificate*/
#if defined(MBEDTLS_FS_IO)

    if (strlen(opt.ca_file)) {
        if (strcmp(opt.ca_file, "none") == 0)
            ret = 0;
        else {
            ret = mbedtls_x509_crt_parse_file(&cacert, opt.ca_file);
            if (ret != 0) {
                printf(" failed\n  !  mbedtls_pk_parse_key returned %d\n\n", ret);
                goto exit;
            }
        }
    }
    else
#endif
#if defined(MBEDTLS_CERTS_C)
    {
        ret = mbedtls_x509_crt_parse(&cacert, (const unsigned char *)mbedtls_test_cas[i], mbedtls_test_cas_len[i]);

        if (ret != 0) {
            printf(" failed\n  !  mbedtls_pk_parse_key returned %d\n\n", ret);
            goto exit;
        }
    }
#else
    {
        ret = 1;
        mbedtls_printf("MBEDTLS_CERTS_C not defined.");
    }
#endif
    /*End Load CA Certificate*/

    printf(" ok\n");

    /*
     * 2. Setup the "listening" UDP socket
     */
    printf("  . Bind on udp/*/4433 ...");
    fflush(stdout);

    if ((ret = mbedtls_net_bind(&listen_fd, "127.0.0.1", "4433", MBEDTLS_NET_PROTO_UDP)) != 0) {
        printf(" failed\n  ! mbedtls_net_bind returned %d\n\n", ret);
        goto exit;
    }

    printf(" ok\n");

    /*
     * 3. Seed the RNG
     */
    printf("  . Seeding the random number generator...");
    fflush(stdout);

    if ((ret = mbedtls_ctr_drbg_seed(
             &ctr_drbg, mbedtls_entropy_func, &entropy, (const unsigned char *)pers, strlen(pers))) != 0) {
        printf(" failed\n  ! mbedtls_ctr_drbg_seed returned %d\n", ret);
        goto exit;
    }

    printf(" ok\n");

    /*
     * 4. Setup stuff
     */
    printf("  . Setting up the DTLS data...");
    fflush(stdout);

    if ((ret = mbedtls_ssl_config_defaults(
             &conf, MBEDTLS_SSL_IS_SERVER, MBEDTLS_SSL_TRANSPORT_DATAGRAM, MBEDTLS_SSL_PRESET_DEFAULT)) != 0) {
        mbedtls_printf(" failed\n  ! mbedtls_ssl_config_defaults returned %d\n\n", ret);
        goto exit;
    }

    mbedtls_ssl_conf_rng(&conf, mbedtls_ctr_drbg_random, &ctr_drbg);
    mbedtls_ssl_conf_dbg(&conf, my_debug, stdout);

#if defined(MBEDTLS_SSL_CACHE_C)
    mbedtls_ssl_conf_session_cache(&conf, &cache, mbedtls_ssl_cache_get, mbedtls_ssl_cache_set);
#endif

    mbedtls_ssl_conf_ca_chain(&conf, &cacert, NULL);
    if ((ret = mbedtls_ssl_conf_own_cert(&conf, &srvcert, &pkey)) != 0) {
        printf(" failed\n  ! mbedtls_ssl_conf_own_cert returned %d\n\n", ret);
        goto exit;
    }

    if (opt.min_version != DFL_MIN_VERSION)
        mbedtls_ssl_conf_min_version(&conf, MBEDTLS_SSL_MAJOR_VERSION_3, opt.min_version);

    if (opt.max_version != DFL_MAJ_VERSION)
        mbedtls_ssl_conf_max_version(&conf, MBEDTLS_SSL_MAJOR_VERSION_3, opt.max_version);

    if ((ret = mbedtls_ssl_cookie_setup(&cookie_ctx, mbedtls_ctr_drbg_random, &ctr_drbg)) != 0) {
        printf(" failed\n  ! mbedtls_ssl_cookie_setup returned %d\n\n", ret);
        goto exit;
    }

    mbedtls_ssl_conf_dtls_cookies(&conf, mbedtls_ssl_cookie_write, mbedtls_ssl_cookie_check, &cookie_ctx);

    if ((ret = mbedtls_ssl_setup(&ssl, &conf)) != 0) {
        printf(" failed\n  ! mbedtls_ssl_setup returned %d\n\n", ret);
        goto exit;
    }

    mbedtls_ssl_set_timer_cb(&ssl, &timer, mbedtls_timing_set_delay, mbedtls_timing_get_delay);

    printf(" ok\n");

reset:
#ifdef MBEDTLS_ERROR_C
    if (ret != 0) {
        char error_buf[100];
        mbedtls_strerror(ret, error_buf, 100);
        printf("Last error was: %d - %s\n\n", ret, error_buf);
    }
#endif

    mbedtls_net_free(&client_fd);

    mbedtls_ssl_session_reset(&ssl);

    /*
     * 3. Wait until a client connects
     */
    printf("  . Waiting for a remote connection ...");
    fflush(stdout);

    if ((ret = mbedtls_net_accept(&listen_fd, &client_fd, client_ip, sizeof(client_ip), &cliip_len)) != 0) {
        printf(" failed\n  ! mbedtls_net_accept returned %d\n\n", ret);
        goto exit;
    }

    /* For HelloVerifyRequest cookies */
    if ((ret = mbedtls_ssl_set_client_transport_id(&ssl, client_ip, cliip_len)) != 0) {
        printf(
            " failed\n  ! "
            "mbedtls_ssl_set_client_transport_id() returned -0x%x\n\n",
            -ret);
        goto exit;
    }

    mbedtls_ssl_set_bio(&ssl, &client_fd, mbedtls_net_send, mbedtls_net_recv, mbedtls_net_recv_timeout);

    printf(" ok\n");

    /*
     * 5. Handshake
     */
    printf("  . Performing the DTLS handshake...");
    fflush(stdout);

    do
        ret = mbedtls_ssl_handshake(&ssl);
    while (ret == MBEDTLS_ERR_SSL_WANT_READ || ret == MBEDTLS_ERR_SSL_WANT_WRITE);

    if (ret == MBEDTLS_ERR_SSL_HELLO_VERIFY_REQUIRED) {
        printf(" hello verification requested\n");
        ret = 0;
        goto reset;
    }
    else if (ret != 0) {
        printf(" failed\n  ! mbedtls_ssl_handshake returned -0x%x\n\n", -ret);
        goto reset;
    }

    printf(" ok\n");

    /*
     * 6. Read the echo Request
     */
    printf("  < Read from client:");
    fflush(stdout);

    len = sizeof(buf) - 1;
    memset(buf, 0, sizeof(buf));

    do
        ret = mbedtls_ssl_read(&ssl, buf, len);
    while (ret == MBEDTLS_ERR_SSL_WANT_READ || ret == MBEDTLS_ERR_SSL_WANT_WRITE);

    if (ret <= 0) {
        switch (ret) {
        case MBEDTLS_ERR_SSL_TIMEOUT:
            printf(" timeout\n\n");
            goto reset;

        case MBEDTLS_ERR_SSL_PEER_CLOSE_NOTIFY:
            printf(" connection was closed gracefully\n");
            ret = 0;
            goto close_notify;

        default:
            printf(" mbedtls_ssl_read returned -0x%x\n\n", -ret);
            goto reset;
        }
    }

    len = ret;
    printf(" %d bytes read\n\n%s\n\n", len, buf);

    /*
     * 7. Write the 200 Response
     */
    printf("  > Write to client:");
    fflush(stdout);

    do
        ret = mbedtls_ssl_write(&ssl, buf, len);
    while (ret == MBEDTLS_ERR_SSL_WANT_READ || ret == MBEDTLS_ERR_SSL_WANT_WRITE);

    if (ret < 0) {
        printf(" failed\n  ! mbedtls_ssl_write returned %d\n\n", ret);
        goto exit;
    }

    len = ret;
    printf(" %d bytes written\n\n%s\n\n", len, buf);

    /*
     * 8. Done, cleanly close the connection
     */
close_notify:
    printf("  . Closing the connection...");

    /* No error checking, the connection might be closed already */
    do
        ret = mbedtls_ssl_close_notify(&ssl);
    while (ret == MBEDTLS_ERR_SSL_WANT_WRITE);
    ret = 0;

    printf(" done\n");
#ifdef _WIN32
    {
        Sleep(1000);
    }
#endif
    goto reset;

    /*
     * Final clean-ups and exit
     */
exit:

#ifdef MBEDTLS_ERROR_C
    if (ret != 0) {
        char error_buf[100];
        mbedtls_strerror(ret, error_buf, 100);
        printf("Last error was: %d - %s\n\n", ret, error_buf);
    }
#endif

    mbedtls_net_free(&client_fd);
    mbedtls_net_free(&listen_fd);

    mbedtls_x509_crt_free(&srvcert);
    mbedtls_pk_free(&pkey);
    mbedtls_ssl_free(&ssl);
    mbedtls_ssl_config_free(&conf);
    mbedtls_ssl_cookie_free(&cookie_ctx);
#if defined(MBEDTLS_SSL_CACHE_C)
    mbedtls_ssl_cache_free(&cache);
#endif
    mbedtls_ctr_drbg_free(&ctr_drbg);
    mbedtls_entropy_free(&entropy);

#if defined(_WIN32)
    printf("  Press Enter to exit this program.\n");
    fflush(stdout);
    getchar();
#endif

    /* Shell can not handle large exit numbers -> 1 for errors */
    if (ret < 0) {
        ret = 1;
        printf("Failed");
    }
    else {
        printf("Passed");
    }

    return (ret);
}
#endif /* MBEDTLS_SSL_SRV_C && MBEDTLS_SSL_PROTO_DTLS &&
          MBEDTLS_SSL_COOKIE_C && MBEDTLS_NET_C && MBEDTLS_ENTROPY_C &&
          MBEDTLS_CTR_DRBG_C && MBEDTLS_X509_CRT_PARSE_C && MBEDTLS_RSA_C
          && MBEDTLS_CERTS_C && MBEDTLS_PEM_PARSE_C && MBEDTLS_TIMING_C */