/* * Simple DTLS client demonstration program * * Copyright (C) 2014, Brainspark B.V. * * This file is part of mbed TLS (https://polarssl.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(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 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 #include #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 */