1/* ssl/d1_lib.c */
2/*
3 * DTLS implementation written by Nagendra Modadugu
4 * (nagendra@cs.stanford.edu) for the OpenSSL project 2005.
5 */
6/* ====================================================================
7 * Copyright (c) 1999-2005 The OpenSSL Project.  All rights reserved.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 *
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 *
16 * 2. Redistributions in binary form must reproduce the above copyright
17 *    notice, this list of conditions and the following disclaimer in
18 *    the documentation and/or other materials provided with the
19 *    distribution.
20 *
21 * 3. All advertising materials mentioning features or use of this
22 *    software must display the following acknowledgment:
23 *    "This product includes software developed by the OpenSSL Project
24 *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
25 *
26 * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
27 *    endorse or promote products derived from this software without
28 *    prior written permission. For written permission, please contact
29 *    openssl-core@OpenSSL.org.
30 *
31 * 5. Products derived from this software may not be called "OpenSSL"
32 *    nor may "OpenSSL" appear in their names without prior written
33 *    permission of the OpenSSL Project.
34 *
35 * 6. Redistributions of any form whatsoever must retain the following
36 *    acknowledgment:
37 *    "This product includes software developed by the OpenSSL Project
38 *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
39 *
40 * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
41 * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
43 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
44 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
45 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
46 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
47 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
49 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
50 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
51 * OF THE POSSIBILITY OF SUCH DAMAGE.
52 * ====================================================================
53 *
54 * This product includes cryptographic software written by Eric Young
55 * (eay@cryptsoft.com).  This product includes software written by Tim
56 * Hudson (tjh@cryptsoft.com).
57 *
58 */
59
60#include <stdio.h>
61#define USE_SOCKETS
62#include <openssl/objects.h>
63#include "ssl_locl.h"
64
65#if defined(OPENSSL_SYS_WIN32) || defined(OPENSSL_SYS_VMS)
66#include <sys/timeb.h>
67#endif
68
69static void get_current_time(struct timeval *t);
70const char dtls1_version_str[]="DTLSv1" OPENSSL_VERSION_PTEXT;
71int dtls1_listen(SSL *s, struct sockaddr *client);
72
73SSL3_ENC_METHOD DTLSv1_enc_data={
74    dtls1_enc,
75	tls1_mac,
76	tls1_setup_key_block,
77	tls1_generate_master_secret,
78	tls1_change_cipher_state,
79	tls1_final_finish_mac,
80	TLS1_FINISH_MAC_LENGTH,
81	tls1_cert_verify_mac,
82	TLS_MD_CLIENT_FINISH_CONST,TLS_MD_CLIENT_FINISH_CONST_SIZE,
83	TLS_MD_SERVER_FINISH_CONST,TLS_MD_SERVER_FINISH_CONST_SIZE,
84	tls1_alert_code,
85	};
86
87long dtls1_default_timeout(void)
88	{
89	/* 2 hours, the 24 hours mentioned in the DTLSv1 spec
90	 * is way too long for http, the cache would over fill */
91	return(60*60*2);
92	}
93
94int dtls1_new(SSL *s)
95	{
96	DTLS1_STATE *d1;
97
98	if (!ssl3_new(s)) return(0);
99	if ((d1=OPENSSL_malloc(sizeof *d1)) == NULL) return (0);
100	memset(d1,0, sizeof *d1);
101
102	/* d1->handshake_epoch=0; */
103
104	d1->unprocessed_rcds.q=pqueue_new();
105	d1->processed_rcds.q=pqueue_new();
106	d1->buffered_messages = pqueue_new();
107	d1->sent_messages=pqueue_new();
108	d1->buffered_app_data.q=pqueue_new();
109
110	if ( s->server)
111		{
112		d1->cookie_len = sizeof(s->d1->cookie);
113		}
114
115	d1->link_mtu = 0;
116	d1->mtu = 0;
117
118	if( ! d1->unprocessed_rcds.q || ! d1->processed_rcds.q
119        || ! d1->buffered_messages || ! d1->sent_messages || ! d1->buffered_app_data.q)
120		{
121        if ( d1->unprocessed_rcds.q) pqueue_free(d1->unprocessed_rcds.q);
122        if ( d1->processed_rcds.q) pqueue_free(d1->processed_rcds.q);
123        if ( d1->buffered_messages) pqueue_free(d1->buffered_messages);
124		if ( d1->sent_messages) pqueue_free(d1->sent_messages);
125		if ( d1->buffered_app_data.q) pqueue_free(d1->buffered_app_data.q);
126		OPENSSL_free(d1);
127		return (0);
128		}
129
130	s->d1=d1;
131	s->method->ssl_clear(s);
132	return(1);
133	}
134
135static void dtls1_clear_queues(SSL *s)
136	{
137    pitem *item = NULL;
138    hm_fragment *frag = NULL;
139	DTLS1_RECORD_DATA *rdata;
140
141    while( (item = pqueue_pop(s->d1->unprocessed_rcds.q)) != NULL)
142        {
143		rdata = (DTLS1_RECORD_DATA *) item->data;
144		if (rdata->rbuf.buf)
145			{
146			OPENSSL_free(rdata->rbuf.buf);
147			}
148        OPENSSL_free(item->data);
149        pitem_free(item);
150        }
151
152    while( (item = pqueue_pop(s->d1->processed_rcds.q)) != NULL)
153        {
154		rdata = (DTLS1_RECORD_DATA *) item->data;
155		if (rdata->rbuf.buf)
156			{
157			OPENSSL_free(rdata->rbuf.buf);
158			}
159        OPENSSL_free(item->data);
160        pitem_free(item);
161        }
162
163    while( (item = pqueue_pop(s->d1->buffered_messages)) != NULL)
164        {
165        frag = (hm_fragment *)item->data;
166        dtls1_hm_fragment_free(frag);
167        pitem_free(item);
168        }
169
170    while ( (item = pqueue_pop(s->d1->sent_messages)) != NULL)
171        {
172        frag = (hm_fragment *)item->data;
173        dtls1_hm_fragment_free(frag);
174        pitem_free(item);
175        }
176
177	while ( (item = pqueue_pop(s->d1->buffered_app_data.q)) != NULL)
178		{
179		rdata = (DTLS1_RECORD_DATA *) item->data;
180		if (rdata->rbuf.buf)
181			{
182			OPENSSL_free(rdata->rbuf.buf);
183			}
184		OPENSSL_free(item->data);
185		pitem_free(item);
186		}
187	}
188
189void dtls1_free(SSL *s)
190	{
191	ssl3_free(s);
192
193	dtls1_clear_queues(s);
194
195    pqueue_free(s->d1->unprocessed_rcds.q);
196    pqueue_free(s->d1->processed_rcds.q);
197    pqueue_free(s->d1->buffered_messages);
198	pqueue_free(s->d1->sent_messages);
199	pqueue_free(s->d1->buffered_app_data.q);
200
201	OPENSSL_free(s->d1);
202	s->d1 = NULL;
203	}
204
205void dtls1_clear(SSL *s)
206	{
207    pqueue unprocessed_rcds;
208    pqueue processed_rcds;
209    pqueue buffered_messages;
210	pqueue sent_messages;
211	pqueue buffered_app_data;
212	unsigned int mtu;
213	unsigned int link_mtu;
214
215	if (s->d1)
216		{
217		unprocessed_rcds = s->d1->unprocessed_rcds.q;
218		processed_rcds = s->d1->processed_rcds.q;
219		buffered_messages = s->d1->buffered_messages;
220		sent_messages = s->d1->sent_messages;
221		buffered_app_data = s->d1->buffered_app_data.q;
222		mtu = s->d1->mtu;
223		link_mtu = s->d1->link_mtu;
224
225		dtls1_clear_queues(s);
226
227		memset(s->d1, 0, sizeof(*(s->d1)));
228
229		if (s->server)
230			{
231			s->d1->cookie_len = sizeof(s->d1->cookie);
232			}
233
234		if (SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)
235			{
236			s->d1->mtu = mtu;
237			s->d1->link_mtu = link_mtu;
238			}
239
240		s->d1->unprocessed_rcds.q = unprocessed_rcds;
241		s->d1->processed_rcds.q = processed_rcds;
242		s->d1->buffered_messages = buffered_messages;
243		s->d1->sent_messages = sent_messages;
244		s->d1->buffered_app_data.q = buffered_app_data;
245		}
246
247	ssl3_clear(s);
248	if (s->options & SSL_OP_CISCO_ANYCONNECT)
249		s->version=DTLS1_BAD_VER;
250	else
251		s->version=DTLS1_VERSION;
252	}
253
254long dtls1_ctrl(SSL *s, int cmd, long larg, void *parg)
255	{
256	int ret=0;
257
258	switch (cmd)
259		{
260	case DTLS_CTRL_GET_TIMEOUT:
261		if (dtls1_get_timeout(s, (struct timeval*) parg) != NULL)
262			{
263			ret = 1;
264			}
265		break;
266	case DTLS_CTRL_HANDLE_TIMEOUT:
267		ret = dtls1_handle_timeout(s);
268		break;
269	case DTLS_CTRL_LISTEN:
270		ret = dtls1_listen(s, parg);
271		break;
272	case SSL_CTRL_CHECK_PROTO_VERSION:
273		/* For library-internal use; checks that the current protocol
274		 * is the highest enabled version (according to s->ctx->method,
275		 * as version negotiation may have changed s->method). */
276#if DTLS_MAX_VERSION != DTLS1_VERSION
277#  error Code needs update for DTLS_method() support beyond DTLS1_VERSION.
278#endif
279		/* Just one protocol version is supported so far;
280		 * fail closed if the version is not as expected. */
281		return s->version == DTLS_MAX_VERSION;
282	case DTLS_CTRL_SET_LINK_MTU:
283		if (larg < (long)dtls1_link_min_mtu())
284			return 0;
285		s->d1->link_mtu = larg;
286		return 1;
287	case DTLS_CTRL_GET_LINK_MIN_MTU:
288		return (long)dtls1_link_min_mtu();
289	case SSL_CTRL_SET_MTU:
290		/*
291		 *  We may not have a BIO set yet so can't call dtls1_min_mtu()
292		 *  We'll have to make do with dtls1_link_min_mtu() and max overhead
293		 */
294		if (larg < (long)dtls1_link_min_mtu() - DTLS1_MAX_MTU_OVERHEAD)
295			return 0;
296		s->d1->mtu = larg;
297		return larg;
298	default:
299		ret = ssl3_ctrl(s, cmd, larg, parg);
300		break;
301		}
302	return(ret);
303	}
304
305/*
306 * As it's impossible to use stream ciphers in "datagram" mode, this
307 * simple filter is designed to disengage them in DTLS. Unfortunately
308 * there is no universal way to identify stream SSL_CIPHER, so we have
309 * to explicitly list their SSL_* codes. Currently RC4 is the only one
310 * available, but if new ones emerge, they will have to be added...
311 */
312const SSL_CIPHER *dtls1_get_cipher(unsigned int u)
313	{
314	const SSL_CIPHER *ciph = ssl3_get_cipher(u);
315
316	if (ciph != NULL)
317		{
318		if (ciph->algorithm_enc == SSL_RC4)
319			return NULL;
320		}
321
322	return ciph;
323	}
324
325void dtls1_start_timer(SSL *s)
326	{
327	/* If timer is not set, initialize duration with 1 second */
328	if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0)
329		{
330		s->d1->timeout_duration = 1;
331		}
332
333	/* Set timeout to current time */
334	get_current_time(&(s->d1->next_timeout));
335
336	/* Add duration to current time */
337	s->d1->next_timeout.tv_sec += s->d1->timeout_duration;
338	BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0, &(s->d1->next_timeout));
339	}
340
341struct timeval* dtls1_get_timeout(SSL *s, struct timeval* timeleft)
342	{
343	struct timeval timenow;
344
345	/* If no timeout is set, just return NULL */
346	if (s->d1->next_timeout.tv_sec == 0 && s->d1->next_timeout.tv_usec == 0)
347		{
348		return NULL;
349		}
350
351	/* Get current time */
352	get_current_time(&timenow);
353
354	/* If timer already expired, set remaining time to 0 */
355	if (s->d1->next_timeout.tv_sec < timenow.tv_sec ||
356		(s->d1->next_timeout.tv_sec == timenow.tv_sec &&
357		 s->d1->next_timeout.tv_usec <= timenow.tv_usec))
358		{
359		memset(timeleft, 0, sizeof(struct timeval));
360		return timeleft;
361		}
362
363	/* Calculate time left until timer expires */
364	memcpy(timeleft, &(s->d1->next_timeout), sizeof(struct timeval));
365	timeleft->tv_sec -= timenow.tv_sec;
366	timeleft->tv_usec -= timenow.tv_usec;
367	if (timeleft->tv_usec < 0)
368		{
369		timeleft->tv_sec--;
370		timeleft->tv_usec += 1000000;
371		}
372
373	/* If remaining time is less than 15 ms, set it to 0
374	 * to prevent issues because of small devergences with
375	 * socket timeouts.
376	 */
377	if (timeleft->tv_sec == 0 && timeleft->tv_usec < 15000)
378		{
379		memset(timeleft, 0, sizeof(struct timeval));
380		}
381
382
383	return timeleft;
384	}
385
386int dtls1_is_timer_expired(SSL *s)
387	{
388	struct timeval timeleft;
389
390	/* Get time left until timeout, return false if no timer running */
391	if (dtls1_get_timeout(s, &timeleft) == NULL)
392		{
393		return 0;
394		}
395
396	/* Return false if timer is not expired yet */
397	if (timeleft.tv_sec > 0 || timeleft.tv_usec > 0)
398		{
399		return 0;
400		}
401
402	/* Timer expired, so return true */
403	return 1;
404	}
405
406void dtls1_double_timeout(SSL *s)
407	{
408	s->d1->timeout_duration *= 2;
409	if (s->d1->timeout_duration > 60)
410		s->d1->timeout_duration = 60;
411	dtls1_start_timer(s);
412	}
413
414void dtls1_stop_timer(SSL *s)
415	{
416	/* Reset everything */
417	memset(&(s->d1->timeout), 0, sizeof(struct dtls1_timeout_st));
418	memset(&(s->d1->next_timeout), 0, sizeof(struct timeval));
419	s->d1->timeout_duration = 1;
420	BIO_ctrl(SSL_get_rbio(s), BIO_CTRL_DGRAM_SET_NEXT_TIMEOUT, 0, &(s->d1->next_timeout));
421	/* Clear retransmission buffer */
422	dtls1_clear_record_buffer(s);
423	}
424
425int dtls1_check_timeout_num(SSL *s)
426	{
427	unsigned int mtu;
428
429	s->d1->timeout.num_alerts++;
430
431	/* Reduce MTU after 2 unsuccessful retransmissions */
432	if (s->d1->timeout.num_alerts > 2
433			&& !(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU))
434		{
435		mtu = BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_GET_FALLBACK_MTU, 0, NULL);
436		if(mtu < s->d1->mtu)
437			s->d1->mtu = mtu;
438		}
439
440	if (s->d1->timeout.num_alerts > DTLS1_TMO_ALERT_COUNT)
441		{
442		/* fail the connection, enough alerts have been sent */
443		SSLerr(SSL_F_DTLS1_CHECK_TIMEOUT_NUM,SSL_R_READ_TIMEOUT_EXPIRED);
444		return -1;
445		}
446
447	return 0;
448	}
449
450int dtls1_handle_timeout(SSL *s)
451	{
452	/* if no timer is expired, don't do anything */
453	if (!dtls1_is_timer_expired(s))
454		{
455		return 0;
456		}
457
458	dtls1_double_timeout(s);
459
460	if (dtls1_check_timeout_num(s) < 0)
461		return -1;
462
463	s->d1->timeout.read_timeouts++;
464	if (s->d1->timeout.read_timeouts > DTLS1_TMO_READ_COUNT)
465		{
466		s->d1->timeout.read_timeouts = 1;
467		}
468
469	dtls1_start_timer(s);
470	return dtls1_retransmit_buffered_messages(s);
471	}
472
473static void get_current_time(struct timeval *t)
474{
475#ifdef OPENSSL_SYS_WIN32
476	struct _timeb tb;
477	_ftime(&tb);
478	t->tv_sec = (long)tb.time;
479	t->tv_usec = (long)tb.millitm * 1000;
480#elif defined(OPENSSL_SYS_VMS)
481	struct timeb tb;
482	ftime(&tb);
483	t->tv_sec = (long)tb.time;
484	t->tv_usec = (long)tb.millitm * 1000;
485#else
486	gettimeofday(t, NULL);
487#endif
488}
489
490int dtls1_listen(SSL *s, struct sockaddr *client)
491	{
492	int ret;
493
494	SSL_set_options(s, SSL_OP_COOKIE_EXCHANGE);
495	s->d1->listen = 1;
496
497	ret = SSL_accept(s);
498	if (ret <= 0) return ret;
499
500	(void) BIO_dgram_get_peer(SSL_get_rbio(s), client);
501	return 1;
502	}
503