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
8 #define MBEDTLS_DECLARE_PRIVATE_IDENTIFIERS
9
10 #include "mbedtls/build_info.h"
11
12 #include "mbedtls/platform.h"
13
14 #if !defined(MBEDTLS_ENTROPY_C) || !defined(MBEDTLS_CTR_DRBG_C) || \
15 !defined(MBEDTLS_NET_C) || !defined(MBEDTLS_SSL_CLI_C) || \
16 !defined(MBEDTLS_TIMING_C) || !defined(MBEDTLS_SSL_PROTO_DTLS) || \
17 !defined(MBEDTLS_PEM_PARSE_C) || !defined(MBEDTLS_X509_CRT_PARSE_C)
main(void)18 int main(void)
19 {
20 mbedtls_printf("MBEDTLS_ENTROPY_C and/or MBEDTLS_CTR_DRBG_C and/or "
21 "MBEDTLS_NET_C and/or MBEDTLS_SSL_CLI_C and/or "
22 "MBEDTLS_TIMING_C and/or MBEDTLS_SSL_PROTO_DTLS and/or "
23 "MBEDTLS_PEM_PARSE_C and/or MBEDTLS_X509_CRT_PARSE_C "
24 "not defined.\n");
25 mbedtls_exit(0);
26 }
27 #else
28
29 #include <string.h>
30
31 #include "mbedtls/net_sockets.h"
32 #include "mbedtls/debug.h"
33 #include "mbedtls/ssl.h"
34 #include "mbedtls/entropy.h"
35 #include "mbedtls/ctr_drbg.h"
36 #include "mbedtls/error.h"
37 #include "mbedtls/timing.h"
38 #include "test/certs.h"
39
40 /* Uncomment out the following line to default to IPv4 and disable IPv6 */
41 //#define FORCE_IPV4
42
43 #define SERVER_PORT "4433"
44 #define SERVER_NAME "localhost"
45
46 #ifdef FORCE_IPV4
47 #define SERVER_ADDR "127.0.0.1" /* Forces IPv4 */
48 #else
49 #define SERVER_ADDR SERVER_NAME
50 #endif
51
52 #define MESSAGE "Echo this"
53
54 #define READ_TIMEOUT_MS 1000
55 #define MAX_RETRY 5
56
57 #define DEBUG_LEVEL 0
58
59
my_debug(void * ctx,int level,const char * file,int line,const char * str)60 static void my_debug(void *ctx, int level,
61 const char *file, int line,
62 const char *str)
63 {
64 ((void) level);
65
66 mbedtls_fprintf((FILE *) ctx, "%s:%04d: %s", file, line, str);
67 fflush((FILE *) ctx);
68 }
69
main(int argc,char * argv[])70 int main(int argc, char *argv[])
71 {
72 int ret, len;
73 mbedtls_net_context server_fd;
74 uint32_t flags;
75 unsigned char buf[1024];
76 const char *pers = "dtls_client";
77 int retry_left = MAX_RETRY;
78
79 mbedtls_entropy_context entropy;
80 mbedtls_ctr_drbg_context ctr_drbg;
81 mbedtls_ssl_context ssl;
82 mbedtls_ssl_config conf;
83 mbedtls_x509_crt cacert;
84 mbedtls_timing_delay_context timer;
85
86 ((void) argc);
87 ((void) argv);
88
89 #if defined(MBEDTLS_DEBUG_C)
90 mbedtls_debug_set_threshold(DEBUG_LEVEL);
91 #endif
92
93 /*
94 * 0. Initialize the RNG and the session data
95 */
96 mbedtls_net_init(&server_fd);
97 mbedtls_ssl_init(&ssl);
98 mbedtls_ssl_config_init(&conf);
99 mbedtls_x509_crt_init(&cacert);
100 mbedtls_ctr_drbg_init(&ctr_drbg);
101 mbedtls_entropy_init(&entropy);
102
103 psa_status_t status = psa_crypto_init();
104 if (status != PSA_SUCCESS) {
105 mbedtls_fprintf(stderr, "Failed to initialize PSA Crypto implementation: %d\n",
106 (int) status);
107 ret = MBEDTLS_ERR_SSL_HW_ACCEL_FAILED;
108 goto exit;
109 }
110
111 mbedtls_printf("\n . Seeding the random number generator...");
112 fflush(stdout);
113
114 if ((ret = mbedtls_ctr_drbg_seed(&ctr_drbg, mbedtls_entropy_func, &entropy,
115 (const unsigned char *) pers,
116 strlen(pers))) != 0) {
117 mbedtls_printf(" failed\n ! mbedtls_ctr_drbg_seed returned %d\n", ret);
118 goto exit;
119 }
120
121 mbedtls_printf(" ok\n");
122
123 /*
124 * 0. Load certificates
125 */
126 mbedtls_printf(" . Loading the CA root certificate ...");
127 fflush(stdout);
128
129 ret = mbedtls_x509_crt_parse(&cacert, (const unsigned char *) mbedtls_test_cas_pem,
130 mbedtls_test_cas_pem_len);
131 if (ret < 0) {
132 mbedtls_printf(" failed\n ! mbedtls_x509_crt_parse returned -0x%x\n\n",
133 (unsigned int) -ret);
134 goto exit;
135 }
136
137 mbedtls_printf(" ok (%d skipped)\n", ret);
138
139 /*
140 * 1. Start the connection
141 */
142 mbedtls_printf(" . Connecting to udp/%s/%s...", SERVER_NAME, SERVER_PORT);
143 fflush(stdout);
144
145 if ((ret = mbedtls_net_connect(&server_fd, SERVER_ADDR,
146 SERVER_PORT, MBEDTLS_NET_PROTO_UDP)) != 0) {
147 mbedtls_printf(" failed\n ! mbedtls_net_connect returned %d\n\n", ret);
148 goto exit;
149 }
150
151 mbedtls_printf(" ok\n");
152
153 /*
154 * 2. Setup stuff
155 */
156 mbedtls_printf(" . Setting up the DTLS structure...");
157 fflush(stdout);
158
159 if ((ret = mbedtls_ssl_config_defaults(&conf,
160 MBEDTLS_SSL_IS_CLIENT,
161 MBEDTLS_SSL_TRANSPORT_DATAGRAM,
162 MBEDTLS_SSL_PRESET_DEFAULT)) != 0) {
163 mbedtls_printf(" failed\n ! mbedtls_ssl_config_defaults returned %d\n\n", ret);
164 goto exit;
165 }
166
167 /* OPTIONAL is usually a bad choice for security, but makes interop easier
168 * in this simplified example, in which the ca chain is hardcoded.
169 * Production code should set a proper ca chain and use REQUIRED. */
170 mbedtls_ssl_conf_authmode(&conf, MBEDTLS_SSL_VERIFY_OPTIONAL);
171 mbedtls_ssl_conf_ca_chain(&conf, &cacert, NULL);
172 mbedtls_ssl_conf_dbg(&conf, my_debug, stdout);
173 mbedtls_ssl_conf_read_timeout(&conf, READ_TIMEOUT_MS);
174
175 if ((ret = mbedtls_ssl_setup(&ssl, &conf)) != 0) {
176 mbedtls_printf(" failed\n ! mbedtls_ssl_setup returned %d\n\n", ret);
177 goto exit;
178 }
179
180 if ((ret = mbedtls_ssl_set_hostname(&ssl, SERVER_NAME)) != 0) {
181 mbedtls_printf(" failed\n ! mbedtls_ssl_set_hostname returned %d\n\n", ret);
182 goto exit;
183 }
184
185 mbedtls_ssl_set_bio(&ssl, &server_fd,
186 mbedtls_net_send, mbedtls_net_recv, mbedtls_net_recv_timeout);
187
188 mbedtls_ssl_set_timer_cb(&ssl, &timer, mbedtls_timing_set_delay,
189 mbedtls_timing_get_delay);
190
191 mbedtls_printf(" ok\n");
192
193 /*
194 * 4. Handshake
195 */
196 mbedtls_printf(" . Performing the DTLS handshake...");
197 fflush(stdout);
198
199 do {
200 ret = mbedtls_ssl_handshake(&ssl);
201 } while (ret == MBEDTLS_ERR_SSL_WANT_READ ||
202 ret == MBEDTLS_ERR_SSL_WANT_WRITE);
203
204 if (ret != 0) {
205 mbedtls_printf(" failed\n ! mbedtls_ssl_handshake returned -0x%x\n\n",
206 (unsigned int) -ret);
207 goto exit;
208 }
209
210 mbedtls_printf(" ok\n");
211
212 /*
213 * 5. Verify the server certificate
214 */
215 mbedtls_printf(" . Verifying peer X.509 certificate...");
216
217 /* In real life, we would have used MBEDTLS_SSL_VERIFY_REQUIRED so that the
218 * handshake would not succeed if the peer's cert is bad. Even if we used
219 * MBEDTLS_SSL_VERIFY_OPTIONAL, we would bail out here if ret != 0 */
220 if ((flags = mbedtls_ssl_get_verify_result(&ssl)) != 0) {
221 #if !defined(MBEDTLS_X509_REMOVE_INFO)
222 char vrfy_buf[512];
223 #endif
224
225 mbedtls_printf(" failed\n");
226
227 #if !defined(MBEDTLS_X509_REMOVE_INFO)
228 mbedtls_x509_crt_verify_info(vrfy_buf, sizeof(vrfy_buf), " ! ", flags);
229
230 mbedtls_printf("%s\n", vrfy_buf);
231 #endif
232 } else {
233 mbedtls_printf(" ok\n");
234 }
235
236 /*
237 * 6. Write the echo request
238 */
239 send_request:
240 mbedtls_printf(" > Write to server:");
241 fflush(stdout);
242
243 len = sizeof(MESSAGE) - 1;
244
245 do {
246 ret = mbedtls_ssl_write(&ssl, (unsigned char *) MESSAGE, len);
247 } while (ret == MBEDTLS_ERR_SSL_WANT_READ ||
248 ret == MBEDTLS_ERR_SSL_WANT_WRITE);
249
250 if (ret < 0) {
251 mbedtls_printf(" failed\n ! mbedtls_ssl_write returned %d\n\n", ret);
252 goto exit;
253 }
254
255 len = ret;
256 mbedtls_printf(" %d bytes written\n\n%s\n\n", len, MESSAGE);
257
258 /*
259 * 7. Read the echo response
260 */
261 mbedtls_printf(" < Read from server:");
262 fflush(stdout);
263
264 len = sizeof(buf) - 1;
265 memset(buf, 0, sizeof(buf));
266
267 do {
268 ret = mbedtls_ssl_read(&ssl, buf, len);
269 } while (ret == MBEDTLS_ERR_SSL_WANT_READ ||
270 ret == MBEDTLS_ERR_SSL_WANT_WRITE);
271
272 if (ret <= 0) {
273 switch (ret) {
274 case MBEDTLS_ERR_SSL_TIMEOUT:
275 mbedtls_printf(" timeout\n\n");
276 if (retry_left-- > 0) {
277 goto send_request;
278 }
279 goto exit;
280
281 case MBEDTLS_ERR_SSL_PEER_CLOSE_NOTIFY:
282 mbedtls_printf(" connection was closed gracefully\n");
283 goto close_notify;
284
285 default:
286 mbedtls_printf(" mbedtls_ssl_read returned -0x%x\n\n", (unsigned int) -ret);
287 goto exit;
288 }
289 }
290
291 len = ret;
292 mbedtls_printf(" %d bytes read\n\n%s\n\n", len, buf);
293
294 /*
295 * 8. Done, cleanly close the connection
296 */
297 close_notify:
298 mbedtls_printf(" . Closing the connection...");
299
300 /* No error checking, the connection might be closed already */
301 do {
302 ret = mbedtls_ssl_close_notify(&ssl);
303 } while (ret == MBEDTLS_ERR_SSL_WANT_WRITE);
304 ret = 0;
305
306 mbedtls_printf(" done\n");
307
308 /*
309 * 9. Final clean-ups and exit
310 */
311 exit:
312
313 #ifdef MBEDTLS_ERROR_C
314 if (ret != 0) {
315 char error_buf[100];
316 mbedtls_strerror(ret, error_buf, 100);
317 mbedtls_printf("Last error was: %d - %s\n\n", ret, error_buf);
318 }
319 #endif
320
321 mbedtls_net_free(&server_fd);
322 mbedtls_x509_crt_free(&cacert);
323 mbedtls_ssl_free(&ssl);
324 mbedtls_ssl_config_free(&conf);
325 mbedtls_ctr_drbg_free(&ctr_drbg);
326 mbedtls_entropy_free(&entropy);
327 mbedtls_psa_crypto_free();
328
329 /* Shell can not handle large exit numbers -> 1 for errors */
330 if (ret < 0) {
331 ret = 1;
332 }
333
334 mbedtls_exit(ret);
335 }
336
337 #endif /* configuration allows running this program */
338