356 lines
10 KiB
C
356 lines
10 KiB
C
/*
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* Simple DTLS client demonstration program
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*
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* Copyright (C) 2014, Brainspark B.V.
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*
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* This file is part of mbed TLS (https://tls.mbed.org)
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#if !defined(MBEDTLS_CONFIG_FILE)
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#include "mbedtls/config.h"
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#else
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#include MBEDTLS_CONFIG_FILE
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#endif
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#if defined(MBEDTLS_PLATFORM_C)
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#include "mbedtls/platform.h"
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#else
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#include <stdio.h>
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#define mbedtls_printf printf
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#define mbedtls_fprintf fprintf
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#endif
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#if !defined(MBEDTLS_SSL_CLI_C) || !defined(MBEDTLS_SSL_PROTO_DTLS) || \
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!defined(MBEDTLS_NET_C) || \
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!defined(MBEDTLS_ENTROPY_C) || !defined(MBEDTLS_CTR_DRBG_C) || \
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!defined(MBEDTLS_X509_CRT_PARSE_C) || !defined(MBEDTLS_RSA_C) || \
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!defined(MBEDTLS_CERTS_C)
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int main( int argc, char *argv[] )
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{
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((void) argc);
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((void) argv);
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mbedtls_printf( "MBEDTLS_SSL_CLI_C and/or MBEDTLS_SSL_PROTO_DTLS and/or "
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"MBEDTLS_NET_C and/or "
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"MBEDTLS_ENTROPY_C and/or MBEDTLS_CTR_DRBG_C and/or "
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"MBEDTLS_X509_CRT_PARSE_C and/or MBEDTLS_RSA_C and/or "
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"MBEDTLS_CERTS_C and/or MBEDTLS_PEM_PARSE_C not defined.\n" );
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return( 0 );
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}
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#else
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#include <string.h>
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#include "mbedtls/net.h"
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#include "mbedtls/debug.h"
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#include "mbedtls/ssl.h"
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#include "mbedtls/entropy.h"
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#include "mbedtls/ctr_drbg.h"
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#include "mbedtls/error.h"
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#include "mbedtls/certs.h"
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#define SERVER_PORT 4433
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#define SERVER_NAME "localhost"
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#define SERVER_ADDR "127.0.0.1" /* forces IPv4 */
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#define MESSAGE "Echo this"
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#define READ_TIMEOUT_MS 1000
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#define MAX_RETRY 5
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#define DEBUG_LEVEL 0
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static void my_debug( void *ctx, int level, const char *str )
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{
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((void) level);
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mbedtls_fprintf( (FILE *) ctx, "%s", str );
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fflush( (FILE *) ctx );
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}
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int main( int argc, char *argv[] )
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{
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int ret, len, server_fd = -1;
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unsigned char buf[1024];
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const char *pers = "dtls_client";
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int retry_left = MAX_RETRY;
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mbedtls_entropy_context entropy;
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mbedtls_ctr_drbg_context ctr_drbg;
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mbedtls_ssl_context ssl;
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mbedtls_ssl_config conf;
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mbedtls_x509_crt cacert;
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((void) argc);
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((void) argv);
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#if defined(MBEDTLS_DEBUG_C)
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mbedtls_debug_set_threshold( DEBUG_LEVEL );
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#endif
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/*
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* 0. Initialize the RNG and the session data
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*/
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mbedtls_ssl_init( &ssl );
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mbedtls_ssl_config_init( &conf );
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mbedtls_x509_crt_init( &cacert );
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mbedtls_ctr_drbg_init( &ctr_drbg );
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mbedtls_printf( "\n . Seeding the random number generator..." );
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fflush( stdout );
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mbedtls_entropy_init( &entropy );
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if( ( ret = mbedtls_ctr_drbg_seed( &ctr_drbg, mbedtls_entropy_func, &entropy,
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(const unsigned char *) pers,
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strlen( pers ) ) ) != 0 )
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{
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mbedtls_printf( " failed\n ! mbedtls_ctr_drbg_seed returned %d\n", ret );
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goto exit;
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}
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mbedtls_printf( " ok\n" );
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/*
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* 0. Load certificates
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*/
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mbedtls_printf( " . Loading the CA root certificate ..." );
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fflush( stdout );
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ret = mbedtls_x509_crt_parse( &cacert, (const unsigned char *) mbedtls_test_cas_pem,
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mbedtls_test_cas_pem_len );
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if( ret < 0 )
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{
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mbedtls_printf( " failed\n ! mbedtls_x509_crt_parse returned -0x%x\n\n", -ret );
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goto exit;
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}
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mbedtls_printf( " ok (%d skipped)\n", ret );
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/*
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* 1. Start the connection
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*/
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mbedtls_printf( " . Connecting to udp/%s/%4d...", SERVER_NAME,
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SERVER_PORT );
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fflush( stdout );
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if( ( ret = mbedtls_net_connect( &server_fd, SERVER_ADDR,
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SERVER_PORT, MBEDTLS_NET_PROTO_UDP ) ) != 0 )
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{
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mbedtls_printf( " failed\n ! mbedtls_net_connect returned %d\n\n", ret );
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goto exit;
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}
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mbedtls_printf( " ok\n" );
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/*
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* 2. Setup stuff
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*/
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mbedtls_printf( " . Setting up the DTLS structure..." );
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fflush( stdout );
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if( ( ret = mbedtls_ssl_config_defaults( &conf,
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MBEDTLS_SSL_IS_CLIENT,
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MBEDTLS_SSL_TRANSPORT_DATAGRAM ) ) != 0 )
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{
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mbedtls_printf( " failed\n ! mbedtls_ssl_config_defaults returned %d\n\n", ret );
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goto exit;
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}
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if( ( ret = mbedtls_ssl_setup( &ssl, &conf ) ) != 0 )
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{
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mbedtls_printf( " failed\n ! mbedtls_ssl_setup returned %d\n\n", ret );
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goto exit;
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}
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/* OPTIONAL is usually a bad choice for security, but makes interop easier
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* in this simplified example, in which the ca chain is hardcoded.
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* Production code should set a proper ca chain and use REQUIRED. */
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mbedtls_ssl_set_authmode( &conf, MBEDTLS_SSL_VERIFY_OPTIONAL );
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mbedtls_ssl_set_ca_chain( &conf, &cacert, NULL );
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if( ( ret = mbedtls_ssl_set_hostname( &ssl, SERVER_NAME ) ) != 0 )
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{
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mbedtls_printf( " failed\n ! mbedtls_ssl_set_hostname returned %d\n\n", ret );
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goto exit;
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}
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mbedtls_ssl_set_rng( &ssl, mbedtls_ctr_drbg_random, &ctr_drbg );
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mbedtls_ssl_set_dbg( &conf, my_debug, stdout );
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mbedtls_ssl_set_bio_timeout( &ssl, &server_fd,
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mbedtls_net_send, mbedtls_net_recv, mbedtls_net_recv_timeout,
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READ_TIMEOUT_MS );
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mbedtls_printf( " ok\n" );
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/*
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* 4. Handshake
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*/
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mbedtls_printf( " . Performing the SSL/TLS handshake..." );
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fflush( stdout );
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do ret = mbedtls_ssl_handshake( &ssl );
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while( ret == MBEDTLS_ERR_NET_WANT_READ ||
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ret == MBEDTLS_ERR_NET_WANT_WRITE );
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if( ret != 0 )
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{
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mbedtls_printf( " failed\n ! mbedtls_ssl_handshake returned -0x%x\n\n", -ret );
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goto exit;
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}
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mbedtls_printf( " ok\n" );
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/*
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* 5. Verify the server certificate
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*/
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mbedtls_printf( " . Verifying peer X.509 certificate..." );
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/* In real life, we would have used MBEDTLS_SSL_VERIFY_REQUIRED so that the
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* handshake would not succeed if the peer's cert is bad. Even if we used
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* MBEDTLS_SSL_VERIFY_OPTIONAL, we would bail out here if ret != 0 */
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if( ( ret = mbedtls_ssl_get_verify_result( &ssl ) ) != 0 )
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{
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mbedtls_printf( " failed\n" );
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if( ( ret & MBEDTLS_X509_BADCERT_EXPIRED ) != 0 )
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mbedtls_printf( " ! server certificate has expired\n" );
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if( ( ret & MBEDTLS_X509_BADCERT_REVOKED ) != 0 )
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mbedtls_printf( " ! server certificate has been revoked\n" );
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if( ( ret & MBEDTLS_X509_BADCERT_CN_MISMATCH ) != 0 )
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mbedtls_printf( " ! CN mismatch (expected CN=%s)\n", SERVER_NAME );
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if( ( ret & MBEDTLS_X509_BADCERT_NOT_TRUSTED ) != 0 )
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mbedtls_printf( " ! self-signed or not signed by a trusted CA\n" );
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mbedtls_printf( "\n" );
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}
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else
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mbedtls_printf( " ok\n" );
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/*
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* 6. Write the echo request
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*/
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send_request:
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mbedtls_printf( " > Write to server:" );
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fflush( stdout );
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len = sizeof( MESSAGE ) - 1;
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do ret = mbedtls_ssl_write( &ssl, (unsigned char *) MESSAGE, len );
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while( ret == MBEDTLS_ERR_NET_WANT_READ ||
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ret == MBEDTLS_ERR_NET_WANT_WRITE );
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if( ret < 0 )
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{
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mbedtls_printf( " failed\n ! mbedtls_ssl_write returned %d\n\n", ret );
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goto exit;
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}
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len = ret;
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mbedtls_printf( " %d bytes written\n\n%s\n\n", len, MESSAGE );
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/*
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* 7. Read the echo response
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*/
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mbedtls_printf( " < Read from server:" );
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fflush( stdout );
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len = sizeof( buf ) - 1;
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memset( buf, 0, sizeof( buf ) );
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do ret = mbedtls_ssl_read( &ssl, buf, len );
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while( ret == MBEDTLS_ERR_NET_WANT_READ ||
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ret == MBEDTLS_ERR_NET_WANT_WRITE );
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if( ret <= 0 )
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{
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switch( ret )
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{
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case MBEDTLS_ERR_NET_TIMEOUT:
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mbedtls_printf( " timeout\n\n" );
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if( retry_left-- > 0 )
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goto send_request;
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goto exit;
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case MBEDTLS_ERR_SSL_PEER_CLOSE_NOTIFY:
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mbedtls_printf( " connection was closed gracefully\n" );
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ret = 0;
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goto close_notify;
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default:
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mbedtls_printf( " mbedtls_ssl_read returned -0x%x\n\n", -ret );
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goto exit;
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}
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}
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len = ret;
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mbedtls_printf( " %d bytes read\n\n%s\n\n", len, buf );
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/*
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* 8. Done, cleanly close the connection
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*/
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close_notify:
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mbedtls_printf( " . Closing the connection..." );
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/* No error checking, the connection might be closed already */
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do ret = mbedtls_ssl_close_notify( &ssl );
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while( ret == MBEDTLS_ERR_NET_WANT_WRITE );
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ret = 0;
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mbedtls_printf( " done\n" );
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/*
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* 9. Final clean-ups and exit
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*/
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exit:
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#ifdef MBEDTLS_ERROR_C
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if( ret != 0 )
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{
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char error_buf[100];
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mbedtls_strerror( ret, error_buf, 100 );
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mbedtls_printf( "Last error was: %d - %s\n\n", ret, error_buf );
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}
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#endif
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if( server_fd != -1 )
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mbedtls_net_close( server_fd );
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mbedtls_x509_crt_free( &cacert );
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mbedtls_ssl_free( &ssl );
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mbedtls_ssl_config_free( &conf );
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mbedtls_ctr_drbg_free( &ctr_drbg );
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mbedtls_entropy_free( &entropy );
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#if defined(_WIN32)
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mbedtls_printf( " + Press Enter to exit this program.\n" );
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fflush( stdout ); getchar();
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#endif
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/* Shell can not handle large exit numbers -> 1 for errors */
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if( ret < 0 )
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ret = 1;
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return( ret );
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}
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#endif /* MBEDTLS_SSL_CLI_C && MBEDTLS_SSL_PROTO_DTLS && MBEDTLS_NET_C &&
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MBEDTLS_ENTROPY_C && MBEDTLS_CTR_DRBG_C &&
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MBEDTLS_X509_CRT_PARSE_C && MBEDTLS_RSA_C && MBEDTLS_CERTS_C &&
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MBEDTLS_PEM_PARSE_C */
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