mbedtls/programs/ssl/dtls_client.c
2014-10-21 16:32:54 +02:00

344 lines
9.1 KiB
C

/*
* Simple DTLS client demonstration program
*
* Copyright (C) 2014, Brainspark B.V.
*
* This file is part of PolarSSL (http://www.polarssl.org)
* Lead Maintainer: Paul Bakker <polarssl_maintainer at polarssl.org>
*
* All rights reserved.
*
* 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(POLARSSL_CONFIG_FILE)
#include "polarssl/config.h"
#else
#include POLARSSL_CONFIG_FILE
#endif
#if !defined(POLARSSL_SSL_CLI_C) || !defined(POLARSSL_SSL_PROTO_DTLS) || \
!defined(POLARSSL_NET_C) || \
!defined(POLARSSL_ENTROPY_C) || !defined(POLARSSL_CTR_DRBG_C) || \
!defined(POLARSSL_X509_CRT_PARSE_C) || !defined(POLARSSL_RSA_C) || \
!defined(POLARSSL_CERTS_C)
#include <stdio.h>
int main( int argc, char *argv[] )
{
((void) argc);
((void) argv);
printf( "POLARSSL_SSL_CLI_C and/or POLARSSL_SSL_PROTO_DTLS and/or "
"POLARSSL_NET_C and/or "
"POLARSSL_ENTROPY_C and/or POLARSSL_CTR_DRBG_C and/or "
"POLARSSL_X509_CRT_PARSE_C and/or POLARSSL_RSA_C and/or "
"POLARSSL_CERTS_C not defined.\n" );
return( 0 );
}
#else
#include <string.h>
#include <stdio.h>
#include "polarssl/net.h"
#include "polarssl/debug.h"
#include "polarssl/ssl.h"
#include "polarssl/entropy.h"
#include "polarssl/ctr_drbg.h"
#include "polarssl/error.h"
#include "polarssl/certs.h"
#define SERVER_PORT 4433
#define SERVER_NAME "localhost"
#define SERVER_ADDR "127.0.0.1" /* forces IPv4 */
#define MESSAGE "Echo this"
#define READ_TIMEOUT_MS 1000
#define MAX_RETRY 5
#define DEBUG_LEVEL 0
static void my_debug( void *ctx, int level, const char *str )
{
((void) level);
fprintf( (FILE *) ctx, "%s", str );
fflush( (FILE *) ctx );
}
int main( int argc, char *argv[] )
{
int ret, len, server_fd = -1;
unsigned char buf[1024];
const char *pers = "dtls_client";
int retry_left = MAX_RETRY;
entropy_context entropy;
ctr_drbg_context ctr_drbg;
ssl_context ssl;
x509_crt cacert;
((void) argc);
((void) argv);
#if defined(POLARSSL_DEBUG_C)
debug_set_threshold( DEBUG_LEVEL );
#endif
/*
* 0. Initialize the RNG and the session data
*/
memset( &ssl, 0, sizeof( ssl_context ) );
x509_crt_init( &cacert );
printf( "\n . Seeding the random number generator..." );
fflush( stdout );
entropy_init( &entropy );
if( ( ret = ctr_drbg_init( &ctr_drbg, entropy_func, &entropy,
(const unsigned char *) pers,
strlen( pers ) ) ) != 0 )
{
printf( " failed\n ! ctr_drbg_init returned %d\n", ret );
goto exit;
}
printf( " ok\n" );
/*
* 0. Initialize certificates
*/
printf( " . Loading the CA root certificate ..." );
fflush( stdout );
#if defined(POLARSSL_CERTS_C)
ret = x509_crt_parse( &cacert, (const unsigned char *) test_ca_list,
strlen( test_ca_list ) );
#else
ret = 1;
printf("POLARSSL_CERTS_C not defined.");
#endif
if( ret < 0 )
{
printf( " failed\n ! x509_crt_parse returned -0x%x\n\n", -ret );
goto exit;
}
printf( " ok (%d skipped)\n", ret );
/*
* 1. Start the connection
*/
printf( " . Connecting to udp/%s/%4d...", SERVER_NAME,
SERVER_PORT );
fflush( stdout );
if( ( ret = net_connect( &server_fd, SERVER_ADDR,
SERVER_PORT, NET_PROTO_UDP ) ) != 0 )
{
printf( " failed\n ! net_connect returned %d\n\n", ret );
goto exit;
}
printf( " ok\n" );
/*
* 2. Setup stuff
*/
printf( " . Setting up the DTLS structure..." );
fflush( stdout );
if( ( ret = ssl_init( &ssl ) ) != 0 )
{
printf( " failed\n ! ssl_init returned %d\n\n", ret );
goto exit;
}
printf( " ok\n" );
ssl_set_endpoint( &ssl, SSL_IS_CLIENT );
ssl_set_transport( &ssl, SSL_TRANSPORT_DATAGRAM );
/* OPTIONAL is usually a bad choice for security, but makes interop easier
* in this simplified example, in which the ca chain is hardcoded.
* Production code should set a proper ca chain and use REQUIRED. */
ssl_set_authmode( &ssl, SSL_VERIFY_OPTIONAL );
ssl_set_ca_chain( &ssl, &cacert, NULL, SERVER_NAME );
ssl_set_rng( &ssl, ctr_drbg_random, &ctr_drbg );
ssl_set_dbg( &ssl, my_debug, stdout );
ssl_set_bio_timeout( &ssl, &server_fd,
net_send, net_recv, net_recv_timeout,
READ_TIMEOUT_MS );
/*
* 4. Handshake
*/
printf( " . Performing the SSL/TLS handshake..." );
fflush( stdout );
do ret = ssl_handshake( &ssl );
while( ret == POLARSSL_ERR_NET_WANT_READ ||
ret == POLARSSL_ERR_NET_WANT_WRITE );
if( ret != 0 )
{
printf( " failed\n ! ssl_handshake returned -0x%x\n\n", -ret );
goto exit;
}
printf( " ok\n" );
/*
* 5. Verify the server certificate
*/
printf( " . Verifying peer X.509 certificate..." );
/* In real life, we would have used SSL_VERIFY_REQUIRED so that the
* handshake would not succeed if the peer's cert is bad. Even if we used
* SSL_VERIFY_OPTIONAL, we would bail out here if ret != 0 */
if( ( ret = ssl_get_verify_result( &ssl ) ) != 0 )
{
printf( " failed\n" );
if( ( ret & BADCERT_EXPIRED ) != 0 )
printf( " ! server certificate has expired\n" );
if( ( ret & BADCERT_REVOKED ) != 0 )
printf( " ! server certificate has been revoked\n" );
if( ( ret & BADCERT_CN_MISMATCH ) != 0 )
printf( " ! CN mismatch (expected CN=%s)\n", SERVER_NAME );
if( ( ret & BADCERT_NOT_TRUSTED ) != 0 )
printf( " ! self-signed or not signed by a trusted CA\n" );
printf( "\n" );
}
else
printf( " ok\n" );
/*
* 6. Write the echo request
*/
send_request:
printf( " > Write to server:" );
fflush( stdout );
len = sizeof( MESSAGE ) - 1;
do ret = ssl_write( &ssl, (unsigned char *) MESSAGE, len );
while( ret == POLARSSL_ERR_NET_WANT_READ ||
ret == POLARSSL_ERR_NET_WANT_WRITE );
if( ret < 0 )
{
printf( " failed\n ! ssl_write returned %d\n\n", ret );
goto exit;
}
len = ret;
printf( " %d bytes written\n\n%s\n\n", len, MESSAGE );
/*
* 7. Read the echo response
*/
printf( " < Read from server:" );
fflush( stdout );
len = sizeof( buf ) - 1;
memset( buf, 0, sizeof( buf ) );
do ret = ssl_read( &ssl, buf, len );
while( ret == POLARSSL_ERR_NET_WANT_READ ||
ret == POLARSSL_ERR_NET_WANT_WRITE );
if( ret <= 0 )
{
switch( ret )
{
case POLARSSL_ERR_NET_TIMEOUT:
printf( " timeout\n\n" );
if( retry_left-- > 0 )
goto send_request;
goto exit;
case POLARSSL_ERR_SSL_PEER_CLOSE_NOTIFY:
printf( " connection was closed gracefully\n" );
ret = 0;
goto close_notify;
default:
printf( " ssl_read returned -0x%x\n\n", -ret );
goto exit;
}
}
len = ret;
printf( " %d bytes read\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 = ssl_close_notify( &ssl );
while( ret == POLARSSL_ERR_NET_WANT_WRITE );
ret = 0;
printf( " done\n" );
/*
* 9. Final clean-ups and exit
*/
exit:
#ifdef POLARSSL_ERROR_C
if( ret != 0 )
{
char error_buf[100];
polarssl_strerror( ret, error_buf, 100 );
printf( "Last error was: %d - %s\n\n", ret, error_buf );
}
#endif
if( server_fd != -1 )
net_close( server_fd );
x509_crt_free( &cacert );
ssl_free( &ssl );
ctr_drbg_free( &ctr_drbg );
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;
return( ret );
}
#endif /* POLARSSL_SSL_CLI_C && POLARSSL_SSL_PROTO_DTLS && POLARSSL_NET_C &&
POLARSSL_ENTROPY_C && POLARSSL_CTR_DRBG_C &&
POLARSSL_X509_CRT_PARSE_C && POLARSSL_RSA_C && POLARSSL_CERTS_C */