1 /*
2 * Simple DTLS client demonstration program
3 *
4 * Copyright The Mbed TLS Contributors
5 * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
6 *
7 * This file is provided under the Apache License 2.0, or the
8 * GNU General Public License v2.0 or later.
9 *
10 * **********
11 * Apache License 2.0:
12 *
13 * Licensed under the Apache License, Version 2.0 (the "License"); you may
14 * not use this file except in compliance with the License.
15 * You may obtain a copy of the License at
16 *
17 * http://www.apache.org/licenses/LICENSE-2.0
18 *
19 * Unless required by applicable law or agreed to in writing, software
20 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
21 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
22 * See the License for the specific language governing permissions and
23 * limitations under the License.
24 *
25 * **********
26 *
27 * **********
28 * GNU General Public License v2.0 or later:
29 *
30 * This program is free software; you can redistribute it and/or modify
31 * it under the terms of the GNU General Public License as published by
32 * the Free Software Foundation; either version 2 of the License, or
33 * (at your option) any later version.
34 *
35 * This program is distributed in the hope that it will be useful,
36 * but WITHOUT ANY WARRANTY; without even the implied warranty of
37 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
38 * GNU General Public License for more details.
39 *
40 * You should have received a copy of the GNU General Public License along
41 * with this program; if not, write to the Free Software Foundation, Inc.,
42 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
43 *
44 * **********
45 */
46
47 #if !defined(MBEDTLS_CONFIG_FILE)
48 #include "mbedtls/config.h"
49 #else
50 #include MBEDTLS_CONFIG_FILE
51 #endif
52
53 #if defined(MBEDTLS_PLATFORM_C)
54 #include "mbedtls/platform.h"
55 #else
56 #include <stdio.h>
57 #include <stdlib.h>
58 #define mbedtls_printf printf
59 #define mbedtls_fprintf fprintf
60 #define mbedtls_exit exit
61 #define MBEDTLS_EXIT_SUCCESS EXIT_SUCCESS
62 #define MBEDTLS_EXIT_FAILURE EXIT_FAILURE
63 #endif
64
65 #if !defined(MBEDTLS_SSL_CLI_C) || !defined(MBEDTLS_SSL_PROTO_DTLS) || \
66 !defined(MBEDTLS_NET_C) || !defined(MBEDTLS_TIMING_C) || \
67 !defined(MBEDTLS_ENTROPY_C) || !defined(MBEDTLS_CTR_DRBG_C) || \
68 !defined(MBEDTLS_X509_CRT_PARSE_C) || !defined(MBEDTLS_RSA_C) || \
69 !defined(MBEDTLS_CERTS_C) || !defined(MBEDTLS_PEM_PARSE_C)
main(void)70 int main( void )
71 {
72 mbedtls_printf( "MBEDTLS_SSL_CLI_C and/or MBEDTLS_SSL_PROTO_DTLS and/or "
73 "MBEDTLS_NET_C and/or MBEDTLS_TIMING_C and/or "
74 "MBEDTLS_ENTROPY_C and/or MBEDTLS_CTR_DRBG_C and/or "
75 "MBEDTLS_X509_CRT_PARSE_C and/or MBEDTLS_RSA_C and/or "
76 "MBEDTLS_CERTS_C and/or MBEDTLS_PEM_PARSE_C not defined.\n" );
77 mbedtls_exit( 0 );
78 }
79 #else
80
81 #include <string.h>
82
83 #include "mbedtls/net_sockets.h"
84 #include "mbedtls/debug.h"
85 #include "mbedtls/ssl.h"
86 #include "mbedtls/entropy.h"
87 #include "mbedtls/ctr_drbg.h"
88 #include "mbedtls/error.h"
89 #include "mbedtls/certs.h"
90 #include "mbedtls/timing.h"
91
92 /* Uncomment out the following line to default to IPv4 and disable IPv6 */
93 //#define FORCE_IPV4
94
95 #define SERVER_PORT "4433"
96 #define SERVER_NAME "localhost"
97
98 #ifdef FORCE_IPV4
99 #define SERVER_ADDR "127.0.0.1" /* Forces IPv4 */
100 #else
101 #define SERVER_ADDR "::1"
102 #endif
103
104 #define MESSAGE "Echo this"
105
106 #define READ_TIMEOUT_MS 1000
107 #define MAX_RETRY 5
108
109 #define DEBUG_LEVEL 0
110
111
my_debug(void * ctx,int level,const char * file,int line,const char * str)112 static void my_debug( void *ctx, int level,
113 const char *file, int line,
114 const char *str )
115 {
116 ((void) level);
117
118 mbedtls_fprintf( (FILE *) ctx, "%s:%04d: %s", file, line, str );
119 fflush( (FILE *) ctx );
120 }
121
main(int argc,char * argv[])122 int main( int argc, char *argv[] )
123 {
124 int ret, len;
125 mbedtls_net_context server_fd;
126 uint32_t flags;
127 unsigned char buf[1024];
128 const char *pers = "dtls_client";
129 int retry_left = MAX_RETRY;
130
131 mbedtls_entropy_context entropy;
132 mbedtls_ctr_drbg_context ctr_drbg;
133 mbedtls_ssl_context ssl;
134 mbedtls_ssl_config conf;
135 mbedtls_x509_crt cacert;
136 mbedtls_timing_delay_context timer;
137
138 ((void) argc);
139 ((void) argv);
140
141 #if defined(MBEDTLS_DEBUG_C)
142 mbedtls_debug_set_threshold( DEBUG_LEVEL );
143 #endif
144
145 /*
146 * 0. Initialize the RNG and the session data
147 */
148 mbedtls_net_init( &server_fd );
149 mbedtls_ssl_init( &ssl );
150 mbedtls_ssl_config_init( &conf );
151 mbedtls_x509_crt_init( &cacert );
152 mbedtls_ctr_drbg_init( &ctr_drbg );
153
154 mbedtls_printf( "\n . Seeding the random number generator..." );
155 fflush( stdout );
156
157 mbedtls_entropy_init( &entropy );
158 if( ( ret = mbedtls_ctr_drbg_seed( &ctr_drbg, mbedtls_entropy_func, &entropy,
159 (const unsigned char *) pers,
160 strlen( pers ) ) ) != 0 )
161 {
162 mbedtls_printf( " failed\n ! mbedtls_ctr_drbg_seed returned %d\n", ret );
163 goto exit;
164 }
165
166 mbedtls_printf( " ok\n" );
167
168 /*
169 * 0. Load certificates
170 */
171 mbedtls_printf( " . Loading the CA root certificate ..." );
172 fflush( stdout );
173
174 ret = mbedtls_x509_crt_parse( &cacert, (const unsigned char *) mbedtls_test_cas_pem,
175 mbedtls_test_cas_pem_len );
176 if( ret < 0 )
177 {
178 mbedtls_printf( " failed\n ! mbedtls_x509_crt_parse returned -0x%x\n\n", -ret );
179 goto exit;
180 }
181
182 mbedtls_printf( " ok (%d skipped)\n", ret );
183
184 /*
185 * 1. Start the connection
186 */
187 mbedtls_printf( " . Connecting to udp/%s/%s...", SERVER_NAME, SERVER_PORT );
188 fflush( stdout );
189
190 if( ( ret = mbedtls_net_connect( &server_fd, SERVER_ADDR,
191 SERVER_PORT, MBEDTLS_NET_PROTO_UDP ) ) != 0 )
192 {
193 mbedtls_printf( " failed\n ! mbedtls_net_connect returned %d\n\n", ret );
194 goto exit;
195 }
196
197 mbedtls_printf( " ok\n" );
198
199 /*
200 * 2. Setup stuff
201 */
202 mbedtls_printf( " . Setting up the DTLS structure..." );
203 fflush( stdout );
204
205 if( ( ret = mbedtls_ssl_config_defaults( &conf,
206 MBEDTLS_SSL_IS_CLIENT,
207 MBEDTLS_SSL_TRANSPORT_DATAGRAM,
208 MBEDTLS_SSL_PRESET_DEFAULT ) ) != 0 )
209 {
210 mbedtls_printf( " failed\n ! mbedtls_ssl_config_defaults returned %d\n\n", ret );
211 goto exit;
212 }
213
214 /* OPTIONAL is usually a bad choice for security, but makes interop easier
215 * in this simplified example, in which the ca chain is hardcoded.
216 * Production code should set a proper ca chain and use REQUIRED. */
217 mbedtls_ssl_conf_authmode( &conf, MBEDTLS_SSL_VERIFY_OPTIONAL );
218 mbedtls_ssl_conf_ca_chain( &conf, &cacert, NULL );
219 mbedtls_ssl_conf_rng( &conf, mbedtls_ctr_drbg_random, &ctr_drbg );
220 mbedtls_ssl_conf_dbg( &conf, my_debug, stdout );
221
222 if( ( ret = mbedtls_ssl_setup( &ssl, &conf ) ) != 0 )
223 {
224 mbedtls_printf( " failed\n ! mbedtls_ssl_setup returned %d\n\n", ret );
225 goto exit;
226 }
227
228 if( ( ret = mbedtls_ssl_set_hostname( &ssl, SERVER_NAME ) ) != 0 )
229 {
230 mbedtls_printf( " failed\n ! mbedtls_ssl_set_hostname returned %d\n\n", ret );
231 goto exit;
232 }
233
234 mbedtls_ssl_set_bio( &ssl, &server_fd,
235 mbedtls_net_send, mbedtls_net_recv, mbedtls_net_recv_timeout );
236
237 mbedtls_ssl_set_timer_cb( &ssl, &timer, mbedtls_timing_set_delay,
238 mbedtls_timing_get_delay );
239
240 mbedtls_printf( " ok\n" );
241
242 /*
243 * 4. Handshake
244 */
245 mbedtls_printf( " . Performing the DTLS handshake..." );
246 fflush( stdout );
247
248 do ret = mbedtls_ssl_handshake( &ssl );
249 while( ret == MBEDTLS_ERR_SSL_WANT_READ ||
250 ret == MBEDTLS_ERR_SSL_WANT_WRITE );
251
252 if( ret != 0 )
253 {
254 mbedtls_printf( " failed\n ! mbedtls_ssl_handshake returned -0x%x\n\n", -ret );
255 goto exit;
256 }
257
258 mbedtls_printf( " ok\n" );
259
260 /*
261 * 5. Verify the server certificate
262 */
263 mbedtls_printf( " . Verifying peer X.509 certificate..." );
264
265 /* In real life, we would have used MBEDTLS_SSL_VERIFY_REQUIRED so that the
266 * handshake would not succeed if the peer's cert is bad. Even if we used
267 * MBEDTLS_SSL_VERIFY_OPTIONAL, we would bail out here if ret != 0 */
268 if( ( flags = mbedtls_ssl_get_verify_result( &ssl ) ) != 0 )
269 {
270 char vrfy_buf[512];
271
272 mbedtls_printf( " failed\n" );
273
274 mbedtls_x509_crt_verify_info( vrfy_buf, sizeof( vrfy_buf ), " ! ", flags );
275
276 mbedtls_printf( "%s\n", vrfy_buf );
277 }
278 else
279 mbedtls_printf( " ok\n" );
280
281 /*
282 * 6. Write the echo request
283 */
284 send_request:
285 mbedtls_printf( " > Write to server:" );
286 fflush( stdout );
287
288 len = sizeof( MESSAGE ) - 1;
289
290 do ret = mbedtls_ssl_write( &ssl, (unsigned char *) MESSAGE, len );
291 while( ret == MBEDTLS_ERR_SSL_WANT_READ ||
292 ret == MBEDTLS_ERR_SSL_WANT_WRITE );
293
294 if( ret < 0 )
295 {
296 mbedtls_printf( " failed\n ! mbedtls_ssl_write returned %d\n\n", ret );
297 goto exit;
298 }
299
300 len = ret;
301 mbedtls_printf( " %d bytes written\n\n%s\n\n", len, MESSAGE );
302
303 /*
304 * 7. Read the echo response
305 */
306 mbedtls_printf( " < Read from server:" );
307 fflush( stdout );
308
309 len = sizeof( buf ) - 1;
310 memset( buf, 0, sizeof( buf ) );
311
312 do ret = mbedtls_ssl_read( &ssl, buf, len );
313 while( ret == MBEDTLS_ERR_SSL_WANT_READ ||
314 ret == MBEDTLS_ERR_SSL_WANT_WRITE );
315
316 if( ret <= 0 )
317 {
318 switch( ret )
319 {
320 case MBEDTLS_ERR_SSL_TIMEOUT:
321 mbedtls_printf( " timeout\n\n" );
322 if( retry_left-- > 0 )
323 goto send_request;
324 goto exit;
325
326 case MBEDTLS_ERR_SSL_PEER_CLOSE_NOTIFY:
327 mbedtls_printf( " connection was closed gracefully\n" );
328 ret = 0;
329 goto close_notify;
330
331 default:
332 mbedtls_printf( " mbedtls_ssl_read returned -0x%x\n\n", -ret );
333 goto exit;
334 }
335 }
336
337 len = ret;
338 mbedtls_printf( " %d bytes read\n\n%s\n\n", len, buf );
339
340 /*
341 * 8. Done, cleanly close the connection
342 */
343 close_notify:
344 mbedtls_printf( " . Closing the connection..." );
345
346 /* No error checking, the connection might be closed already */
347 do ret = mbedtls_ssl_close_notify( &ssl );
348 while( ret == MBEDTLS_ERR_SSL_WANT_WRITE );
349 ret = 0;
350
351 mbedtls_printf( " done\n" );
352
353 /*
354 * 9. Final clean-ups and exit
355 */
356 exit:
357
358 #ifdef MBEDTLS_ERROR_C
359 if( ret != 0 )
360 {
361 char error_buf[100];
362 mbedtls_strerror( ret, error_buf, 100 );
363 mbedtls_printf( "Last error was: %d - %s\n\n", ret, error_buf );
364 }
365 #endif
366
367 mbedtls_net_free( &server_fd );
368
369 mbedtls_x509_crt_free( &cacert );
370 mbedtls_ssl_free( &ssl );
371 mbedtls_ssl_config_free( &conf );
372 mbedtls_ctr_drbg_free( &ctr_drbg );
373 mbedtls_entropy_free( &entropy );
374
375 #if defined(_WIN32)
376 mbedtls_printf( " + Press Enter to exit this program.\n" );
377 fflush( stdout ); getchar();
378 #endif
379
380 /* Shell can not handle large exit numbers -> 1 for errors */
381 if( ret < 0 )
382 ret = 1;
383
384 mbedtls_exit( ret );
385 }
386 #endif /* MBEDTLS_SSL_CLI_C && MBEDTLS_SSL_PROTO_DTLS && MBEDTLS_NET_C &&
387 MBEDTLD_TIMING_C && MBEDTLS_ENTROPY_C && MBEDTLS_CTR_DRBG_C &&
388 MBEDTLS_X509_CRT_PARSE_C && MBEDTLS_RSA_C && MBEDTLS_CERTS_C &&
389 MBEDTLS_PEM_PARSE_C */
390