/* * Simple DTLS client demonstration program * * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved * 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 #define mbedtls_printf printf #define mbedtls_fprintf fprintf #endif #if !defined(MBEDTLS_SSL_CLI_C) || !defined(MBEDTLS_SSL_PROTO_DTLS) || \ !defined(MBEDTLS_NET_C) || !defined(MBEDTLS_TIMING_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) int main( void ) { mbedtls_printf( "MBEDTLS_SSL_CLI_C and/or MBEDTLS_SSL_PROTO_DTLS and/or " "MBEDTLS_NET_C and/or MBEDTLS_TIMING_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 not defined.\n" ); return( 0 ); } #else #include #include "mbedtls/net_sockets.h" #include "mbedtls/debug.h" #include "mbedtls/ssl.h" #include "mbedtls/entropy.h" #include "mbedtls/ctr_drbg.h" #include "mbedtls/error.h" #include "mbedtls/certs.h" #include "mbedtls/timing.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 *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, len; mbedtls_net_context server_fd; uint32_t flags; unsigned char buf[1024]; const char *pers = "dtls_client"; int retry_left = MAX_RETRY; mbedtls_entropy_context entropy; mbedtls_ctr_drbg_context ctr_drbg; mbedtls_ssl_context ssl; mbedtls_ssl_config conf; mbedtls_x509_crt cacert; mbedtls_timing_delay_context timer; ((void) argc); ((void) argv); #if defined(MBEDTLS_DEBUG_C) mbedtls_debug_set_threshold( DEBUG_LEVEL ); #endif /* * 0. Initialize the RNG and the session data */ mbedtls_net_init( &server_fd ); mbedtls_ssl_init( &ssl ); mbedtls_ssl_config_init( &conf ); mbedtls_x509_crt_init( &cacert ); mbedtls_ctr_drbg_init( &ctr_drbg ); mbedtls_printf( "\n . Seeding the random number generator..." ); fflush( stdout ); mbedtls_entropy_init( &entropy ); 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" ); /* * 0. Load certificates */ mbedtls_printf( " . Loading the CA root certificate ..." ); fflush( stdout ); ret = mbedtls_x509_crt_parse( &cacert, (const unsigned char *) mbedtls_test_cas_pem, mbedtls_test_cas_pem_len ); if( ret < 0 ) { mbedtls_printf( " failed\n ! mbedtls_x509_crt_parse returned -0x%x\n\n", -ret ); goto exit; } mbedtls_printf( " ok (%d skipped)\n", ret ); /* * 1. Start the connection */ mbedtls_printf( " . Connecting to udp/%s/%s...", SERVER_NAME, SERVER_PORT ); fflush( stdout ); if( ( ret = mbedtls_net_connect( &server_fd, SERVER_ADDR, SERVER_PORT, MBEDTLS_NET_PROTO_UDP ) ) != 0 ) { mbedtls_printf( " failed\n ! mbedtls_net_connect returned %d\n\n", ret ); goto exit; } mbedtls_printf( " ok\n" ); /* * 2. Setup stuff */ mbedtls_printf( " . Setting up the DTLS structure..." ); fflush( stdout ); if( ( ret = mbedtls_ssl_config_defaults( &conf, MBEDTLS_SSL_IS_CLIENT, MBEDTLS_SSL_TRANSPORT_DATAGRAM, MBEDTLS_SSL_PRESET_DEFAULT ) ) != 0 ) { mbedtls_printf( " failed\n ! mbedtls_ssl_config_defaults returned %d\n\n", ret ); goto exit; } /* 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. */ mbedtls_ssl_conf_authmode( &conf, MBEDTLS_SSL_VERIFY_OPTIONAL ); mbedtls_ssl_conf_ca_chain( &conf, &cacert, NULL ); mbedtls_ssl_conf_rng( &conf, mbedtls_ctr_drbg_random, &ctr_drbg ); mbedtls_ssl_conf_dbg( &conf, my_debug, stdout ); if( ( ret = mbedtls_ssl_setup( &ssl, &conf ) ) != 0 ) { mbedtls_printf( " failed\n ! mbedtls_ssl_setup returned %d\n\n", ret ); goto exit; } if( ( ret = mbedtls_ssl_set_hostname( &ssl, SERVER_NAME ) ) != 0 ) { mbedtls_printf( " failed\n ! mbedtls_ssl_set_hostname returned %d\n\n", ret ); goto exit; } mbedtls_ssl_set_bio( &ssl, &server_fd, mbedtls_net_send, mbedtls_net_recv, mbedtls_net_recv_timeout ); mbedtls_ssl_set_timer_cb( &ssl, &timer, mbedtls_timing_set_delay, mbedtls_timing_get_delay ); mbedtls_printf( " ok\n" ); /* * 4. Handshake */ mbedtls_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 != 0 ) { mbedtls_printf( " failed\n ! mbedtls_ssl_handshake returned -0x%x\n\n", -ret ); goto exit; } mbedtls_printf( " ok\n" ); /* * 5. Verify the server certificate */ mbedtls_printf( " . Verifying peer X.509 certificate..." ); /* In real life, we would have used MBEDTLS_SSL_VERIFY_REQUIRED so that the * handshake would not succeed if the peer's cert is bad. Even if we used * MBEDTLS_SSL_VERIFY_OPTIONAL, we would bail out here if ret != 0 */ if( ( flags = mbedtls_ssl_get_verify_result( &ssl ) ) != 0 ) { char vrfy_buf[512]; mbedtls_printf( " failed\n" ); mbedtls_x509_crt_verify_info( vrfy_buf, sizeof( vrfy_buf ), " ! ", flags ); mbedtls_printf( "%s\n", vrfy_buf ); } else mbedtls_printf( " ok\n" ); /* * 6. Write the echo request */ send_request: mbedtls_printf( " > Write to server:" ); fflush( stdout ); len = sizeof( MESSAGE ) - 1; do ret = mbedtls_ssl_write( &ssl, (unsigned char *) MESSAGE, len ); while( ret == MBEDTLS_ERR_SSL_WANT_READ || ret == MBEDTLS_ERR_SSL_WANT_WRITE ); if( ret < 0 ) { 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\n", len, MESSAGE ); /* * 7. Read the echo response */ mbedtls_printf( " < Read from server:" ); 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: mbedtls_printf( " timeout\n\n" ); if( retry_left-- > 0 ) goto send_request; goto exit; case MBEDTLS_ERR_SSL_PEER_CLOSE_NOTIFY: mbedtls_printf( " connection was closed gracefully\n" ); ret = 0; goto close_notify; default: mbedtls_printf( " mbedtls_ssl_read returned -0x%x\n\n", -ret ); goto exit; } } len = ret; mbedtls_printf( " %d bytes read\n\n%s\n\n", len, buf ); /* * 8. Done, cleanly close the connection */ close_notify: mbedtls_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; mbedtls_printf( " done\n" ); /* * 9. Final clean-ups and exit */ exit: #ifdef MBEDTLS_ERROR_C if( ret != 0 ) { char error_buf[100]; mbedtls_strerror( ret, error_buf, 100 ); mbedtls_printf( "Last error was: %d - %s\n\n", ret, error_buf ); } #endif mbedtls_net_free( &server_fd ); mbedtls_x509_crt_free( &cacert ); 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 /* Shell can not handle large exit numbers -> 1 for errors */ if( ret < 0 ) ret = 1; return( ret ); } #endif /* MBEDTLS_SSL_CLI_C && MBEDTLS_SSL_PROTO_DTLS && MBEDTLS_NET_C && MBEDTLD_TIMING_C && MBEDTLS_ENTROPY_C && MBEDTLS_CTR_DRBG_C && MBEDTLS_X509_CRT_PARSE_C && MBEDTLS_RSA_C && MBEDTLS_CERTS_C && MBEDTLS_PEM_PARSE_C */