programs/ssl/ssl_fork_server.c - security/mbedtls - Rivoreo Source Code Repositories

 /*
  *  SSL server demonstration program using fork() for handling multiple clients
  *
  *  Copyright (C) 2006-2013, ARM Limited, All Rights Reserved
  *
  *  This file is part of mbed TLS (https://tls.mbed.org)
  *
  *  This program 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.
  *
  *  This program 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.
  */

 #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_fprintf    fprintf
 #define mbedtls_printf     printf
 #endif

 #if !defined(MBEDTLS_BIGNUM_C) || !defined(MBEDTLS_CERTS_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_CERTS_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");
     return( 0 );
 }
 #elif defined(_WIN32)
 int main( void )
 {
     mbedtls_printf("_WIN32 defined. This application requires fork() and signals "
            "to work correctly.\n");
     return( 0 );
 }
 #else

 #include "mbedtls/entropy.h"
 #include "mbedtls/ctr_drbg.h"
 #include "mbedtls/certs.h"
 #include "mbedtls/x509.h"
 #include "mbedtls/ssl.h"
 #include "mbedtls/net.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 *str )
 {
     if( level < DEBUG_LEVEL )
     {
         mbedtls_fprintf( (FILE *) ctx, "%s", str );
         fflush(  (FILE *) ctx  );
     }
 }

 int main( void )
 {
     int ret, len, cnt = 0, pid;
     int listen_fd;
     int client_fd = -1;
     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_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 );

     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\n  ! mbedtls_ctr_drbg_seed returned %d\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\n  !  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\n  !  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 );
     if( ret != 0 )
     {
         mbedtls_printf( " failed\n  !  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\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 );

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

     mbedtls_printf( " ok\n" );

     while( 1 )
     {
         /*
          * 3. Wait until a client connects
          */
         client_fd = -1;
         memset( &ssl, 0, sizeof( ssl ) );

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

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

         mbedtls_printf( " ok\n" );

         /*
          * 3.5. Forking server thread
          */

         pid = fork();

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

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

         mbedtls_printf( " ok\n" );

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

             close( client_fd );
             continue;
         }

         close( listen_fd );

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

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

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

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

         mbedtls_printf( " ok\n" );

         /*
          * 5. Handshake
          */
         mbedtls_printf( "  . Performing the SSL/TLS handshake..." );
         fflush( stdout );

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

         mbedtls_printf( " ok\n" );

         /*
          * 6. Read the HTTP Request
          */
         mbedtls_printf( "  < Read from client:" );
         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( " connection was closed gracefully\n" );
                         break;

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

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

                 break;
             }

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

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

         /*
          * 7. Write the 200 Response
          */
         mbedtls_printf( "  > Write to client:" );
         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( " failed\n  ! peer closed the connection\n\n" );
                     goto exit;
                 }

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

             mbedtls_net_usleep( 1000000 );
         }

         mbedtls_ssl_close_notify( &ssl );
         goto exit;
     }

 exit:

     if( client_fd != -1 )
         mbedtls_net_close( client_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(_WIN32)
     mbedtls_printf( "  Press Enter to exit this program.\n" );
     fflush( stdout ); getchar();
 #endif

     return( ret );
 }
 #endif /* MBEDTLS_BIGNUM_C && MBEDTLS_CERTS_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 (C) 2006-2013, ARM Limited, All Rights Reserved
	*
	* This file is part of mbed TLS (https://tls.mbed.org)
	*
	* This program 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.
	*
	* This program 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.
	*/

	#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_fprintf fprintf
	#define mbedtls_printf printf
	#endif

	#if !defined(MBEDTLS_BIGNUM_C) \|\| !defined(MBEDTLS_CERTS_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_CERTS_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");
	return( 0 );
	}
	#elif defined(_WIN32)
	int main( void )
	{
	mbedtls_printf("_WIN32 defined. This application requires fork() and signals "
	"to work correctly.\n");
	return( 0 );
	}
	#else

	#include "mbedtls/entropy.h"
	#include "mbedtls/ctr_drbg.h"
	#include "mbedtls/certs.h"
	#include "mbedtls/x509.h"
	#include "mbedtls/ssl.h"
	#include "mbedtls/net.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 str )
	{
	if( level < DEBUG_LEVEL )
	{
	mbedtls_fprintf( (FILE *) ctx, "%s", str );
	fflush( (FILE *) ctx );
	}
	}

	int main( void )
	{
	int ret, len, cnt = 0, pid;
	int listen_fd;
	int client_fd = -1;
	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_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 );

	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\n ! mbedtls_ctr_drbg_seed returned %d\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\n ! 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\n ! 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 );
	if( ret != 0 )
	{
	mbedtls_printf( " failed\n ! 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\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 );

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

	mbedtls_printf( " ok\n" );

	while( 1 )
	{
	/*
	* 3. Wait until a client connects
	*/
	client_fd = -1;
	memset( &ssl, 0, sizeof( ssl ) );

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

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

	mbedtls_printf( " ok\n" );

	/*
	* 3.5. Forking server thread
	*/

	pid = fork();

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

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

	mbedtls_printf( " ok\n" );

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

	close( client_fd );
	continue;
	}

	close( listen_fd );

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

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

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

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

	mbedtls_printf( " ok\n" );

	/*
	* 5. Handshake
	*/
	mbedtls_printf( " . Performing the SSL/TLS handshake..." );
	fflush( stdout );

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

	mbedtls_printf( " ok\n" );

	/*
	* 6. Read the HTTP Request
	*/
	mbedtls_printf( " < Read from client:" );
	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( " connection was closed gracefully\n" );
	break;

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

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

	break;
	}

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

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

	/*
	* 7. Write the 200 Response
	*/
	mbedtls_printf( " > Write to client:" );
	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( " failed\n ! peer closed the connection\n\n" );
	goto exit;
	}

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

	mbedtls_net_usleep( 1000000 );
	}

	mbedtls_ssl_close_notify( &ssl );
	goto exit;
	}

	exit:

	if( client_fd != -1 )
	mbedtls_net_close( client_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(_WIN32)
	mbedtls_printf( " Press Enter to exit this program.\n" );
	fflush( stdout ); getchar();
	#endif

	return( ret );
	}
	#endif /* MBEDTLS_BIGNUM_C && MBEDTLS_CERTS_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 */