programs/ssl/ssl_fork_server.c - mirror/mbed-tls.git - TrustedFirmware Git Browser

 /*
  *  SSL server demonstration program using fork() for handling multiple clients
  *
  *  Copyright The Mbed TLS Contributors
  *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
  */

 #include "mbedtls/build_info.h"

 #include "mbedtls/platform.h"

 #if !defined(MBEDTLS_BIGNUM_C) || !defined(MBEDTLS_ENTROPY_C) ||          \
     !defined(MBEDTLS_SSL_TLS_C) || !defined(MBEDTLS_SSL_SRV_C) ||         \
     !defined(MBEDTLS_NET_C) || !defined(MBEDTLS_RSA_C) ||                 \
     !defined(MBEDTLS_CTR_DRBG_C) || !defined(MBEDTLS_X509_CRT_PARSE_C) || \
     !defined(MBEDTLS_TIMING_C) || !defined(MBEDTLS_FS_IO) ||              \
     !defined(MBEDTLS_PEM_PARSE_C)
 int main(int argc, char *argv[])
 {
     ((void) argc);
     ((void) argv);

     mbedtls_printf("MBEDTLS_BIGNUM_C and/or MBEDTLS_ENTROPY_C "
                    "and/or MBEDTLS_SSL_TLS_C and/or MBEDTLS_SSL_SRV_C and/or "
                    "MBEDTLS_NET_C and/or MBEDTLS_RSA_C and/or "
                    "MBEDTLS_CTR_DRBG_C and/or MBEDTLS_X509_CRT_PARSE_C and/or "
                    "MBEDTLS_TIMING_C and/or MBEDTLS_PEM_PARSE_C not defined.\n");
     mbedtls_exit(0);
 }
 #elif defined(_WIN32)
 int main(void)
 {
     mbedtls_printf("_WIN32 defined. This application requires fork() and signals "
                    "to work correctly.\n");
     mbedtls_exit(0);
 }
 #else

 #include "mbedtls/entropy.h"
 #include "mbedtls/ctr_drbg.h"
 #include "test/certs.h"
 #include "mbedtls/x509.h"
 #include "mbedtls/ssl.h"
 #include "mbedtls/net_sockets.h"
 #include "mbedtls/timing.h"

 #include <string.h>
 #include <signal.h>

 #if !defined(_MSC_VER) || defined(EFIX64) || defined(EFI32)
 #include <unistd.h>
 #endif

 #define HTTP_RESPONSE \
     "HTTP/1.0 200 OK\r\nContent-Type: text/html\r\n\r\n" \
     "<h2>Mbed TLS Test Server</h2>\r\n" \
     "<p>Successful connection using: %s</p>\r\n"

 #define DEBUG_LEVEL 0


 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(void)
 {
     int ret = 1, len, cnt = 0, pid;
     int exit_code = MBEDTLS_EXIT_FAILURE;
     mbedtls_net_context listen_fd, client_fd;
     unsigned char buf[1024];
     const char *pers = "ssl_fork_server";

     mbedtls_entropy_context entropy;
     mbedtls_ctr_drbg_context ctr_drbg;
     mbedtls_ssl_context ssl;
     mbedtls_ssl_config conf;
     mbedtls_x509_crt srvcert;
     mbedtls_pk_context pkey;

     mbedtls_net_init(&listen_fd);
     mbedtls_net_init(&client_fd);
     mbedtls_ssl_init(&ssl);
     mbedtls_ssl_config_init(&conf);
     mbedtls_entropy_init(&entropy);
     mbedtls_pk_init(&pkey);
     mbedtls_x509_crt_init(&srvcert);
     mbedtls_ctr_drbg_init(&ctr_drbg);

 #if defined(MBEDTLS_USE_PSA_CRYPTO)
     psa_status_t status = psa_crypto_init();
     if (status != PSA_SUCCESS) {
         mbedtls_fprintf(stderr, "Failed to initialize PSA Crypto implementation: %d\n",
                         (int) status);
         goto exit;
     }
 #endif /* MBEDTLS_USE_PSA_CRYPTO */

     signal(SIGCHLD, SIG_IGN);

     /*
      * 0. Initial seeding of the RNG
      */
     mbedtls_printf("\n  . Initial seeding of the random generator...");
     fflush(stdout);

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

     mbedtls_printf(" ok\n");

     /*
      * 1. Load the certificates and private RSA key
      */
     mbedtls_printf("  . 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().
      */
     ret = mbedtls_x509_crt_parse(&srvcert, (const unsigned char *) mbedtls_test_srv_crt,
                                  mbedtls_test_srv_crt_len);
     if (ret != 0) {
         mbedtls_printf(" failed!  mbedtls_x509_crt_parse returned %d\n\n", ret);
         goto exit;
     }

     ret = mbedtls_x509_crt_parse(&srvcert, (const unsigned char *) mbedtls_test_cas_pem,
                                  mbedtls_test_cas_pem_len);
     if (ret != 0) {
         mbedtls_printf(" failed!  mbedtls_x509_crt_parse returned %d\n\n", ret);
         goto exit;
     }

     ret =  mbedtls_pk_parse_key(&pkey, (const unsigned char *) mbedtls_test_srv_key,
                                 mbedtls_test_srv_key_len, NULL, 0,
                                 mbedtls_ctr_drbg_random, &ctr_drbg);
     if (ret != 0) {
         mbedtls_printf(" failed!  mbedtls_pk_parse_key returned %d\n\n", ret);
         goto exit;
     }

     mbedtls_printf(" ok\n");

     /*
      * 1b. Prepare SSL configuration
      */
     mbedtls_printf("  . Configuring SSL...");
     fflush(stdout);

     if ((ret = mbedtls_ssl_config_defaults(&conf,
                                            MBEDTLS_SSL_IS_SERVER,
                                            MBEDTLS_SSL_TRANSPORT_STREAM,
                                            MBEDTLS_SSL_PRESET_DEFAULT)) != 0) {
         mbedtls_printf(" failed!  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);

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

     mbedtls_printf(" ok\n");

     /*
      * 2. Setup the listening TCP socket
      */
     mbedtls_printf("  . Bind on https://localhost:4433/ ...");
     fflush(stdout);

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

     mbedtls_printf(" ok\n");

     while (1) {
         /*
          * 3. Wait until a client connects
          */
         mbedtls_net_init(&client_fd);
         mbedtls_ssl_init(&ssl);

         mbedtls_printf("  . Waiting for a remote connection ...\n");
         fflush(stdout);

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

         /*
          * 3.5. Forking server thread
          */

         mbedtls_printf("  . Forking to handle connection ...");
         fflush(stdout);

         pid = fork();

         if (pid < 0) {
             mbedtls_printf(" failed!  fork returned %d\n\n", pid);
             goto exit;
         }

         if (pid != 0) {
             mbedtls_printf(" ok\n");
             mbedtls_net_close(&client_fd);

             if ((ret = mbedtls_ctr_drbg_reseed(&ctr_drbg,
                                                (const unsigned char *) "parent",
                                                6)) != 0) {
                 mbedtls_printf(" failed!  mbedtls_ctr_drbg_reseed returned %d\n\n", ret);
                 goto exit;
             }

             continue;
         }

         mbedtls_net_close(&listen_fd);

         pid = getpid();

         /*
          * 4. Setup stuff
          */
         mbedtls_printf("pid %d: Setting up the SSL data.\n", pid);
         fflush(stdout);

         if ((ret = mbedtls_ctr_drbg_reseed(&ctr_drbg,
                                            (const unsigned char *) "child",
                                            5)) != 0) {
             mbedtls_printf(
                 "pid %d: SSL setup failed!  mbedtls_ctr_drbg_reseed returned %d\n\n",
                 pid, ret);
             goto exit;
         }

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

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

         mbedtls_printf("pid %d: SSL setup ok\n", pid);

         /*
          * 5. Handshake
          */
         mbedtls_printf("pid %d: Performing the SSL/TLS handshake.\n", pid);
         fflush(stdout);

         while ((ret = mbedtls_ssl_handshake(&ssl)) != 0) {
             if (ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE) {
                 mbedtls_printf(
                     "pid %d: SSL handshake failed!  mbedtls_ssl_handshake returned %d\n\n",
                     pid, ret);
                 goto exit;
             }
         }

         mbedtls_printf("pid %d: SSL handshake ok\n", pid);

         /*
          * 6. Read the HTTP Request
          */
         mbedtls_printf("pid %d: Start reading from client.\n", pid);
         fflush(stdout);

         do {
             len = sizeof(buf) - 1;
             memset(buf, 0, sizeof(buf));
             ret = mbedtls_ssl_read(&ssl, buf, len);

             if (ret == MBEDTLS_ERR_SSL_WANT_READ || ret == MBEDTLS_ERR_SSL_WANT_WRITE) {
                 continue;
             }

             if (ret <= 0) {
                 switch (ret) {
                     case MBEDTLS_ERR_SSL_PEER_CLOSE_NOTIFY:
                         mbedtls_printf("pid %d: connection was closed gracefully\n", pid);
                         break;

                     case MBEDTLS_ERR_NET_CONN_RESET:
                         mbedtls_printf("pid %d: connection was reset by peer\n", pid);
                         break;

                     default:
                         mbedtls_printf("pid %d: mbedtls_ssl_read returned %d\n", pid, ret);
                         break;
                 }

                 break;
             }

             len = ret;
             mbedtls_printf("pid %d: %d bytes read\n\n%s", pid, len, (char *) buf);

             if (ret > 0) {
                 break;
             }
         } while (1);

         /*
          * 7. Write the 200 Response
          */
         mbedtls_printf("pid %d: Start writing to client.\n", pid);
         fflush(stdout);

         len = sprintf((char *) buf, HTTP_RESPONSE,
                       mbedtls_ssl_get_ciphersuite(&ssl));

         while (cnt++ < 100) {
             while ((ret = mbedtls_ssl_write(&ssl, buf, len)) <= 0) {
                 if (ret == MBEDTLS_ERR_NET_CONN_RESET) {
                     mbedtls_printf(
                         "pid %d: Write failed!  peer closed the connection\n\n", pid);
                     goto exit;
                 }

                 if (ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE) {
                     mbedtls_printf(
                         "pid %d: Write failed!  mbedtls_ssl_write returned %d\n\n",
                         pid, ret);
                     goto exit;
                 }
             }
             len = ret;
             mbedtls_printf("pid %d: %d bytes written\n\n%s\n", pid, len, (char *) buf);

             mbedtls_net_usleep(1000000);
         }

         mbedtls_ssl_close_notify(&ssl);
         goto exit;
     }

     exit_code = MBEDTLS_EXIT_SUCCESS;

 exit:
     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_ctr_drbg_free(&ctr_drbg);
     mbedtls_entropy_free(&entropy);
 #if defined(MBEDTLS_USE_PSA_CRYPTO)
     mbedtls_psa_crypto_free();
 #endif /* MBEDTLS_USE_PSA_CRYPTO */

     mbedtls_exit(exit_code);
 }
 #endif /* MBEDTLS_BIGNUM_C && MBEDTLS_ENTROPY_C &&
           MBEDTLS_SSL_TLS_C && MBEDTLS_SSL_SRV_C && MBEDTLS_NET_C &&
           MBEDTLS_RSA_C && MBEDTLS_CTR_DRBG_C && MBEDTLS_PEM_PARSE_C &&
           ! _WIN32 */
	/*
	* SSL server demonstration program using fork() for handling multiple clients
	*
	* Copyright The Mbed TLS Contributors
	* SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
	*/

	#include "mbedtls/build_info.h"

	#include "mbedtls/platform.h"

	#if !defined(MBEDTLS_BIGNUM_C) \|\| !defined(MBEDTLS_ENTROPY_C) \|\| \
	!defined(MBEDTLS_SSL_TLS_C) \|\| !defined(MBEDTLS_SSL_SRV_C) \|\| \
	!defined(MBEDTLS_NET_C) \|\| !defined(MBEDTLS_RSA_C) \|\| \
	!defined(MBEDTLS_CTR_DRBG_C) \|\| !defined(MBEDTLS_X509_CRT_PARSE_C) \|\| \
	!defined(MBEDTLS_TIMING_C) \|\| !defined(MBEDTLS_FS_IO) \|\| \
	!defined(MBEDTLS_PEM_PARSE_C)
	int main(int argc, char *argv[])
	{
	((void) argc);
	((void) argv);

	mbedtls_printf("MBEDTLS_BIGNUM_C and/or MBEDTLS_ENTROPY_C "
	"and/or MBEDTLS_SSL_TLS_C and/or MBEDTLS_SSL_SRV_C and/or "
	"MBEDTLS_NET_C and/or MBEDTLS_RSA_C and/or "
	"MBEDTLS_CTR_DRBG_C and/or MBEDTLS_X509_CRT_PARSE_C and/or "
	"MBEDTLS_TIMING_C and/or MBEDTLS_PEM_PARSE_C not defined.\n");
	mbedtls_exit(0);
	}
	#elif defined(_WIN32)
	int main(void)
	{
	mbedtls_printf("_WIN32 defined. This application requires fork() and signals "
	"to work correctly.\n");
	mbedtls_exit(0);
	}
	#else

	#include "mbedtls/entropy.h"
	#include "mbedtls/ctr_drbg.h"
	#include "test/certs.h"
	#include "mbedtls/x509.h"
	#include "mbedtls/ssl.h"
	#include "mbedtls/net_sockets.h"
	#include "mbedtls/timing.h"

	#include <string.h>
	#include <signal.h>

	#if !defined(_MSC_VER) \|\| defined(EFIX64) \|\| defined(EFI32)
	#include <unistd.h>
	#endif

	#define HTTP_RESPONSE \
	"HTTP/1.0 200 OK\r\nContent-Type: text/html\r\n\r\n" \
	"<h2>Mbed TLS Test Server</h2>\r\n" \
	"<p>Successful connection using: %s</p>\r\n"

	#define DEBUG_LEVEL 0


	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(void)
	{
	int ret = 1, len, cnt = 0, pid;
	int exit_code = MBEDTLS_EXIT_FAILURE;
	mbedtls_net_context listen_fd, client_fd;
	unsigned char buf[1024];
	const char *pers = "ssl_fork_server";

	mbedtls_entropy_context entropy;
	mbedtls_ctr_drbg_context ctr_drbg;
	mbedtls_ssl_context ssl;
	mbedtls_ssl_config conf;
	mbedtls_x509_crt srvcert;
	mbedtls_pk_context pkey;

	mbedtls_net_init(&listen_fd);
	mbedtls_net_init(&client_fd);
	mbedtls_ssl_init(&ssl);
	mbedtls_ssl_config_init(&conf);
	mbedtls_entropy_init(&entropy);
	mbedtls_pk_init(&pkey);
	mbedtls_x509_crt_init(&srvcert);
	mbedtls_ctr_drbg_init(&ctr_drbg);

	#if defined(MBEDTLS_USE_PSA_CRYPTO)
	psa_status_t status = psa_crypto_init();
	if (status != PSA_SUCCESS) {
	mbedtls_fprintf(stderr, "Failed to initialize PSA Crypto implementation: %d\n",
	(int) status);
	goto exit;
	}
	#endif /* MBEDTLS_USE_PSA_CRYPTO */

	signal(SIGCHLD, SIG_IGN);

	/*
	* 0. Initial seeding of the RNG
	*/
	mbedtls_printf("\n . Initial seeding of the random generator...");
	fflush(stdout);

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

	mbedtls_printf(" ok\n");

	/*
	* 1. Load the certificates and private RSA key
	*/
	mbedtls_printf(" . 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().
	*/
	ret = mbedtls_x509_crt_parse(&srvcert, (const unsigned char *) mbedtls_test_srv_crt,
	mbedtls_test_srv_crt_len);
	if (ret != 0) {
	mbedtls_printf(" failed! mbedtls_x509_crt_parse returned %d\n\n", ret);
	goto exit;
	}

	ret = mbedtls_x509_crt_parse(&srvcert, (const unsigned char *) mbedtls_test_cas_pem,
	mbedtls_test_cas_pem_len);
	if (ret != 0) {
	mbedtls_printf(" failed! mbedtls_x509_crt_parse returned %d\n\n", ret);
	goto exit;
	}

	ret = mbedtls_pk_parse_key(&pkey, (const unsigned char *) mbedtls_test_srv_key,
	mbedtls_test_srv_key_len, NULL, 0,
	mbedtls_ctr_drbg_random, &ctr_drbg);
	if (ret != 0) {
	mbedtls_printf(" failed! mbedtls_pk_parse_key returned %d\n\n", ret);
	goto exit;
	}

	mbedtls_printf(" ok\n");

	/*
	* 1b. Prepare SSL configuration
	*/
	mbedtls_printf(" . Configuring SSL...");
	fflush(stdout);

	if ((ret = mbedtls_ssl_config_defaults(&conf,
	MBEDTLS_SSL_IS_SERVER,
	MBEDTLS_SSL_TRANSPORT_STREAM,
	MBEDTLS_SSL_PRESET_DEFAULT)) != 0) {
	mbedtls_printf(" failed! 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);

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

	mbedtls_printf(" ok\n");

	/*
	* 2. Setup the listening TCP socket
	*/
	mbedtls_printf(" . Bind on https://localhost:4433/ ...");
	fflush(stdout);

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

	mbedtls_printf(" ok\n");

	while (1) {
	/*
	* 3. Wait until a client connects
	*/
	mbedtls_net_init(&client_fd);
	mbedtls_ssl_init(&ssl);

	mbedtls_printf(" . Waiting for a remote connection ...\n");
	fflush(stdout);

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

	/*
	* 3.5. Forking server thread
	*/

	mbedtls_printf(" . Forking to handle connection ...");
	fflush(stdout);

	pid = fork();

	if (pid < 0) {
	mbedtls_printf(" failed! fork returned %d\n\n", pid);
	goto exit;
	}

	if (pid != 0) {
	mbedtls_printf(" ok\n");
	mbedtls_net_close(&client_fd);

	if ((ret = mbedtls_ctr_drbg_reseed(&ctr_drbg,
	(const unsigned char *) "parent",
	6)) != 0) {
	mbedtls_printf(" failed! mbedtls_ctr_drbg_reseed returned %d\n\n", ret);
	goto exit;
	}

	continue;
	}

	mbedtls_net_close(&listen_fd);

	pid = getpid();

	/*
	* 4. Setup stuff
	*/
	mbedtls_printf("pid %d: Setting up the SSL data.\n", pid);
	fflush(stdout);

	if ((ret = mbedtls_ctr_drbg_reseed(&ctr_drbg,
	(const unsigned char *) "child",
	5)) != 0) {
	mbedtls_printf(
	"pid %d: SSL setup failed! mbedtls_ctr_drbg_reseed returned %d\n\n",
	pid, ret);
	goto exit;
	}

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

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

	mbedtls_printf("pid %d: SSL setup ok\n", pid);

	/*
	* 5. Handshake
	*/
	mbedtls_printf("pid %d: Performing the SSL/TLS handshake.\n", pid);
	fflush(stdout);

	while ((ret = mbedtls_ssl_handshake(&ssl)) != 0) {
	if (ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE) {
	mbedtls_printf(
	"pid %d: SSL handshake failed! mbedtls_ssl_handshake returned %d\n\n",
	pid, ret);
	goto exit;
	}
	}

	mbedtls_printf("pid %d: SSL handshake ok\n", pid);

	/*
	* 6. Read the HTTP Request
	*/
	mbedtls_printf("pid %d: Start reading from client.\n", pid);
	fflush(stdout);

	do {
	len = sizeof(buf) - 1;
	memset(buf, 0, sizeof(buf));
	ret = mbedtls_ssl_read(&ssl, buf, len);

	if (ret == MBEDTLS_ERR_SSL_WANT_READ \|\| ret == MBEDTLS_ERR_SSL_WANT_WRITE) {
	continue;
	}

	if (ret <= 0) {
	switch (ret) {
	case MBEDTLS_ERR_SSL_PEER_CLOSE_NOTIFY:
	mbedtls_printf("pid %d: connection was closed gracefully\n", pid);
	break;

	case MBEDTLS_ERR_NET_CONN_RESET:
	mbedtls_printf("pid %d: connection was reset by peer\n", pid);
	break;

	default:
	mbedtls_printf("pid %d: mbedtls_ssl_read returned %d\n", pid, ret);
	break;
	}

	break;
	}

	len = ret;
	mbedtls_printf("pid %d: %d bytes read\n\n%s", pid, len, (char *) buf);

	if (ret > 0) {
	break;
	}
	} while (1);

	/*
	* 7. Write the 200 Response
	*/
	mbedtls_printf("pid %d: Start writing to client.\n", pid);
	fflush(stdout);

	len = sprintf((char *) buf, HTTP_RESPONSE,
	mbedtls_ssl_get_ciphersuite(&ssl));

	while (cnt++ < 100) {
	while ((ret = mbedtls_ssl_write(&ssl, buf, len)) <= 0) {
	if (ret == MBEDTLS_ERR_NET_CONN_RESET) {
	mbedtls_printf(
	"pid %d: Write failed! peer closed the connection\n\n", pid);
	goto exit;
	}

	if (ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE) {
	mbedtls_printf(
	"pid %d: Write failed! mbedtls_ssl_write returned %d\n\n",
	pid, ret);
	goto exit;
	}
	}
	len = ret;
	mbedtls_printf("pid %d: %d bytes written\n\n%s\n", pid, len, (char *) buf);

	mbedtls_net_usleep(1000000);
	}

	mbedtls_ssl_close_notify(&ssl);
	goto exit;
	}

	exit_code = MBEDTLS_EXIT_SUCCESS;

	exit:
	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_ctr_drbg_free(&ctr_drbg);
	mbedtls_entropy_free(&entropy);
	#if defined(MBEDTLS_USE_PSA_CRYPTO)
	mbedtls_psa_crypto_free();
	#endif /* MBEDTLS_USE_PSA_CRYPTO */

	mbedtls_exit(exit_code);
	}
	#endif /* MBEDTLS_BIGNUM_C && MBEDTLS_ENTROPY_C &&
	MBEDTLS_SSL_TLS_C && MBEDTLS_SSL_SRV_C && MBEDTLS_NET_C &&
	MBEDTLS_RSA_C && MBEDTLS_CTR_DRBG_C && MBEDTLS_PEM_PARSE_C &&
	! _WIN32 */