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