xref: /dragonfly/crypto/libressl/ssl/d1_both.c (revision de0e0e4d)
1 /* $OpenBSD: d1_both.c,v 1.81 2022/02/05 14:54:10 jsing Exp $ */
2 /*
3  * DTLS implementation written by Nagendra Modadugu
4  * (nagendra@cs.stanford.edu) for the OpenSSL project 2005.
5  */
6 /* ====================================================================
7  * Copyright (c) 1998-2005 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 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
60  * All rights reserved.
61  *
62  * This package is an SSL implementation written
63  * by Eric Young (eay@cryptsoft.com).
64  * The implementation was written so as to conform with Netscapes SSL.
65  *
66  * This library is free for commercial and non-commercial use as long as
67  * the following conditions are aheared to.  The following conditions
68  * apply to all code found in this distribution, be it the RC4, RSA,
69  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
70  * included with this distribution is covered by the same copyright terms
71  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
72  *
73  * Copyright remains Eric Young's, and as such any Copyright notices in
74  * the code are not to be removed.
75  * If this package is used in a product, Eric Young should be given attribution
76  * as the author of the parts of the library used.
77  * This can be in the form of a textual message at program startup or
78  * in documentation (online or textual) provided with the package.
79  *
80  * Redistribution and use in source and binary forms, with or without
81  * modification, are permitted provided that the following conditions
82  * are met:
83  * 1. Redistributions of source code must retain the copyright
84  *    notice, this list of conditions and the following disclaimer.
85  * 2. Redistributions in binary form must reproduce the above copyright
86  *    notice, this list of conditions and the following disclaimer in the
87  *    documentation and/or other materials provided with the distribution.
88  * 3. All advertising materials mentioning features or use of this software
89  *    must display the following acknowledgement:
90  *    "This product includes cryptographic software written by
91  *     Eric Young (eay@cryptsoft.com)"
92  *    The word 'cryptographic' can be left out if the rouines from the library
93  *    being used are not cryptographic related :-).
94  * 4. If you include any Windows specific code (or a derivative thereof) from
95  *    the apps directory (application code) you must include an acknowledgement:
96  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
97  *
98  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
99  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
100  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
101  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
102  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
103  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
104  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
105  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
106  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
107  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
108  * SUCH DAMAGE.
109  *
110  * The licence and distribution terms for any publically available version or
111  * derivative of this code cannot be changed.  i.e. this code cannot simply be
112  * copied and put under another distribution licence
113  * [including the GNU Public Licence.]
114  */
115 
116 #include <limits.h>
117 #include <stdio.h>
118 #include <string.h>
119 
120 #include <openssl/buffer.h>
121 #include <openssl/evp.h>
122 #include <openssl/objects.h>
123 #include <openssl/x509.h>
124 
125 #include "bytestring.h"
126 #include "dtls_locl.h"
127 #include "pqueue.h"
128 #include "ssl_locl.h"
129 
130 #define RSMBLY_BITMASK_SIZE(msg_len) (((msg_len) + 7) / 8)
131 
132 #define RSMBLY_BITMASK_MARK(bitmask, start, end) { \
133 			if ((end) - (start) <= 8) { \
134 				long ii; \
135 				for (ii = (start); ii < (end); ii++) bitmask[((ii) >> 3)] |= (1 << ((ii) & 7)); \
136 			} else { \
137 				long ii; \
138 				bitmask[((start) >> 3)] |= bitmask_start_values[((start) & 7)]; \
139 				for (ii = (((start) >> 3) + 1); ii < ((((end) - 1)) >> 3); ii++) bitmask[ii] = 0xff; \
140 				bitmask[(((end) - 1) >> 3)] |= bitmask_end_values[((end) & 7)]; \
141 			} }
142 
143 #define RSMBLY_BITMASK_IS_COMPLETE(bitmask, msg_len, is_complete) { \
144 			long ii; \
145 			OPENSSL_assert((msg_len) > 0); \
146 			is_complete = 1; \
147 			if (bitmask[(((msg_len) - 1) >> 3)] != bitmask_end_values[((msg_len) & 7)]) is_complete = 0; \
148 			if (is_complete) for (ii = (((msg_len) - 1) >> 3) - 1; ii >= 0 ; ii--) \
149 				if (bitmask[ii] != 0xff) { is_complete = 0; break; } }
150 
151 static const unsigned char bitmask_start_values[] = {
152 	0xff, 0xfe, 0xfc, 0xf8, 0xf0, 0xe0, 0xc0, 0x80
153 };
154 static const unsigned char bitmask_end_values[] = {
155 	0xff, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f
156 };
157 
158 /* XDTLS:  figure out the right values */
159 static const unsigned int g_probable_mtu[] = {1500 - 28, 512 - 28, 256 - 28};
160 
161 static unsigned int dtls1_guess_mtu(unsigned int curr_mtu);
162 static void dtls1_fix_message_header(SSL *s, unsigned long frag_off,
163     unsigned long frag_len);
164 static int dtls1_write_message_header(const struct hm_header_st *msg_hdr,
165     unsigned long frag_off, unsigned long frag_len, unsigned char *p);
166 static long dtls1_get_message_fragment(SSL *s, int st1, int stn, long max,
167     int *ok);
168 
169 void dtls1_hm_fragment_free(hm_fragment *frag);
170 
171 static hm_fragment *
dtls1_hm_fragment_new(unsigned long frag_len,int reassembly)172 dtls1_hm_fragment_new(unsigned long frag_len, int reassembly)
173 {
174 	hm_fragment *frag;
175 
176 	if ((frag = calloc(1, sizeof(*frag))) == NULL)
177 		goto err;
178 
179 	if (frag_len > 0) {
180 		if ((frag->fragment = calloc(1, frag_len)) == NULL)
181 			goto err;
182 	}
183 
184 	/* Initialize reassembly bitmask if necessary. */
185 	if (reassembly) {
186 		if ((frag->reassembly = calloc(1,
187 		    RSMBLY_BITMASK_SIZE(frag_len))) == NULL)
188 			goto err;
189 	}
190 
191 	return frag;
192 
193  err:
194 	dtls1_hm_fragment_free(frag);
195 	return NULL;
196 }
197 
198 void
dtls1_hm_fragment_free(hm_fragment * frag)199 dtls1_hm_fragment_free(hm_fragment *frag)
200 {
201 	if (frag == NULL)
202 		return;
203 
204 	free(frag->fragment);
205 	free(frag->reassembly);
206 	free(frag);
207 }
208 
209 /* send s->internal->init_buf in records of type 'type' (SSL3_RT_HANDSHAKE or SSL3_RT_CHANGE_CIPHER_SPEC) */
210 int
dtls1_do_write(SSL * s,int type)211 dtls1_do_write(SSL *s, int type)
212 {
213 	int ret;
214 	int curr_mtu;
215 	unsigned int len, frag_off;
216 	size_t overhead;
217 
218 	/* AHA!  Figure out the MTU, and stick to the right size */
219 	if (s->d1->mtu < dtls1_min_mtu() &&
220 	    !(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) {
221 		s->d1->mtu = BIO_ctrl(SSL_get_wbio(s),
222 		    BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
223 
224 		/*
225 		 * I've seen the kernel return bogus numbers when it
226 		 * doesn't know the MTU (ie., the initial write), so just
227 		 * make sure we have a reasonable number
228 		 */
229 		if (s->d1->mtu < dtls1_min_mtu()) {
230 			s->d1->mtu = 0;
231 			s->d1->mtu = dtls1_guess_mtu(s->d1->mtu);
232 			BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SET_MTU,
233 			    s->d1->mtu, NULL);
234 		}
235 	}
236 
237 	OPENSSL_assert(s->d1->mtu >= dtls1_min_mtu());
238 	/* should have something reasonable now */
239 
240 	if (s->internal->init_off == 0  && type == SSL3_RT_HANDSHAKE)
241 		OPENSSL_assert(s->internal->init_num ==
242 		    (int)s->d1->w_msg_hdr.msg_len + DTLS1_HM_HEADER_LENGTH);
243 
244 	if (!tls12_record_layer_write_overhead(s->internal->rl, &overhead))
245 		return -1;
246 
247 	frag_off = 0;
248 	while (s->internal->init_num) {
249 		curr_mtu = s->d1->mtu - BIO_wpending(SSL_get_wbio(s)) -
250 		    DTLS1_RT_HEADER_LENGTH - overhead;
251 
252 		if (curr_mtu <= DTLS1_HM_HEADER_LENGTH) {
253 			/* grr.. we could get an error if MTU picked was wrong */
254 			ret = BIO_flush(SSL_get_wbio(s));
255 			if (ret <= 0)
256 				return ret;
257 			curr_mtu = s->d1->mtu - DTLS1_RT_HEADER_LENGTH -
258 			    overhead;
259 		}
260 
261 		if (s->internal->init_num > curr_mtu)
262 			len = curr_mtu;
263 		else
264 			len = s->internal->init_num;
265 
266 		/* XDTLS: this function is too long.  split out the CCS part */
267 		if (type == SSL3_RT_HANDSHAKE) {
268 			if (s->internal->init_off != 0) {
269 				OPENSSL_assert(s->internal->init_off > DTLS1_HM_HEADER_LENGTH);
270 				s->internal->init_off -= DTLS1_HM_HEADER_LENGTH;
271 				s->internal->init_num += DTLS1_HM_HEADER_LENGTH;
272 
273 				if (s->internal->init_num > curr_mtu)
274 					len = curr_mtu;
275 				else
276 					len = s->internal->init_num;
277 			}
278 
279 			dtls1_fix_message_header(s, frag_off,
280 			    len - DTLS1_HM_HEADER_LENGTH);
281 
282 			if (!dtls1_write_message_header(&s->d1->w_msg_hdr,
283 			    s->d1->w_msg_hdr.frag_off, s->d1->w_msg_hdr.frag_len,
284 			    (unsigned char *)&s->internal->init_buf->data[s->internal->init_off]))
285 				return -1;
286 
287 			OPENSSL_assert(len >= DTLS1_HM_HEADER_LENGTH);
288 		}
289 
290 		ret = dtls1_write_bytes(s, type,
291 		    &s->internal->init_buf->data[s->internal->init_off], len);
292 		if (ret < 0) {
293 			/*
294 			 * Might need to update MTU here, but we don't know
295 			 * which previous packet caused the failure -- so
296 			 * can't really retransmit anything.  continue as
297 			 * if everything is fine and wait for an alert to
298 			 * handle the retransmit
299 			 */
300 			if (BIO_ctrl(SSL_get_wbio(s),
301 			    BIO_CTRL_DGRAM_MTU_EXCEEDED, 0, NULL) > 0)
302 				s->d1->mtu = BIO_ctrl(SSL_get_wbio(s),
303 				    BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
304 			else
305 				return (-1);
306 		} else {
307 
308 			/*
309 			 * Bad if this assert fails, only part of the
310 			 * handshake message got sent.  but why would
311 			 * this happen?
312 			 */
313 			OPENSSL_assert(len == (unsigned int)ret);
314 
315 			if (type == SSL3_RT_HANDSHAKE &&
316 			    !s->d1->retransmitting) {
317 				/*
318 				 * Should not be done for 'Hello Request's,
319 				 * but in that case we'll ignore the result
320 				 * anyway
321 				 */
322 				unsigned char *p = (unsigned char *)&s->internal->init_buf->data[s->internal->init_off];
323 				const struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
324 				int xlen;
325 
326 				if (frag_off == 0) {
327 					/*
328 					 * Reconstruct message header is if it
329 					 * is being sent in single fragment
330 					 */
331 					if (!dtls1_write_message_header(msg_hdr,
332 					    0, msg_hdr->msg_len, p))
333 						return (-1);
334 					xlen = ret;
335 				} else {
336 					p += DTLS1_HM_HEADER_LENGTH;
337 					xlen = ret - DTLS1_HM_HEADER_LENGTH;
338 				}
339 
340 				tls1_transcript_record(s, p, xlen);
341 			}
342 
343 			if (ret == s->internal->init_num) {
344 				if (s->internal->msg_callback)
345 					s->internal->msg_callback(1, s->version, type,
346 					    s->internal->init_buf->data,
347 					    (size_t)(s->internal->init_off + s->internal->init_num),
348 					    s, s->internal->msg_callback_arg);
349 
350 				s->internal->init_off = 0;
351 				/* done writing this message */
352 				s->internal->init_num = 0;
353 
354 				return (1);
355 			}
356 			s->internal->init_off += ret;
357 			s->internal->init_num -= ret;
358 			frag_off += (ret -= DTLS1_HM_HEADER_LENGTH);
359 		}
360 	}
361 	return (0);
362 }
363 
364 
365 /*
366  * Obtain handshake message of message type 'mt' (any if mt == -1),
367  * maximum acceptable body length 'max'.
368  * Read an entire handshake message.  Handshake messages arrive in
369  * fragments.
370  */
371 int
dtls1_get_message(SSL * s,int st1,int stn,int mt,long max)372 dtls1_get_message(SSL *s, int st1, int stn, int mt, long max)
373 {
374 	struct hm_header_st *msg_hdr;
375 	unsigned char *p;
376 	unsigned long msg_len;
377 	int i, al, ok;
378 
379 	/*
380 	 * s3->internal->tmp is used to store messages that are unexpected, caused
381 	 * by the absence of an optional handshake message
382 	 */
383 	if (s->s3->hs.tls12.reuse_message) {
384 		s->s3->hs.tls12.reuse_message = 0;
385 		if ((mt >= 0) && (s->s3->hs.tls12.message_type != mt)) {
386 			al = SSL_AD_UNEXPECTED_MESSAGE;
387 			SSLerror(s, SSL_R_UNEXPECTED_MESSAGE);
388 			goto fatal_err;
389 		}
390 		s->internal->init_msg = s->internal->init_buf->data + DTLS1_HM_HEADER_LENGTH;
391 		s->internal->init_num = (int)s->s3->hs.tls12.message_size;
392 		return 1;
393 	}
394 
395 	msg_hdr = &s->d1->r_msg_hdr;
396 	memset(msg_hdr, 0, sizeof(struct hm_header_st));
397 
398  again:
399 	i = dtls1_get_message_fragment(s, st1, stn, max, &ok);
400 	if (i == DTLS1_HM_BAD_FRAGMENT ||
401 	    i == DTLS1_HM_FRAGMENT_RETRY)  /* bad fragment received */
402 		goto again;
403 	else if (i <= 0 && !ok)
404 		return i;
405 
406 	p = (unsigned char *)s->internal->init_buf->data;
407 	msg_len = msg_hdr->msg_len;
408 
409 	/* reconstruct message header */
410 	if (!dtls1_write_message_header(msg_hdr, 0, msg_len, p))
411 		return -1;
412 
413 	msg_len += DTLS1_HM_HEADER_LENGTH;
414 
415 	tls1_transcript_record(s, p, msg_len);
416 	if (s->internal->msg_callback)
417 		s->internal->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, p, msg_len,
418 		    s, s->internal->msg_callback_arg);
419 
420 	memset(msg_hdr, 0, sizeof(struct hm_header_st));
421 
422 	/* Don't change sequence numbers while listening */
423 	if (!s->d1->listen)
424 		s->d1->handshake_read_seq++;
425 
426 	s->internal->init_msg = s->internal->init_buf->data + DTLS1_HM_HEADER_LENGTH;
427 	return 1;
428 
429  fatal_err:
430 	ssl3_send_alert(s, SSL3_AL_FATAL, al);
431 	return -1;
432 }
433 
434 static int
dtls1_preprocess_fragment(SSL * s,struct hm_header_st * msg_hdr,int max)435 dtls1_preprocess_fragment(SSL *s, struct hm_header_st *msg_hdr, int max)
436 {
437 	size_t frag_off, frag_len, msg_len;
438 
439 	msg_len = msg_hdr->msg_len;
440 	frag_off = msg_hdr->frag_off;
441 	frag_len = msg_hdr->frag_len;
442 
443 	/* sanity checking */
444 	if ((frag_off + frag_len) > msg_len) {
445 		SSLerror(s, SSL_R_EXCESSIVE_MESSAGE_SIZE);
446 		return SSL_AD_ILLEGAL_PARAMETER;
447 	}
448 
449 	if ((frag_off + frag_len) > (unsigned long)max) {
450 		SSLerror(s, SSL_R_EXCESSIVE_MESSAGE_SIZE);
451 		return SSL_AD_ILLEGAL_PARAMETER;
452 	}
453 
454 	if ( s->d1->r_msg_hdr.frag_off == 0) /* first fragment */
455 	{
456 		/*
457 		 * msg_len is limited to 2^24, but is effectively checked
458 		 * against max above
459 		 */
460 		if (!BUF_MEM_grow_clean(s->internal->init_buf,
461 		    msg_len + DTLS1_HM_HEADER_LENGTH)) {
462 			SSLerror(s, ERR_R_BUF_LIB);
463 			return SSL_AD_INTERNAL_ERROR;
464 		}
465 
466 		s->s3->hs.tls12.message_size = msg_len;
467 		s->d1->r_msg_hdr.msg_len = msg_len;
468 		s->s3->hs.tls12.message_type = msg_hdr->type;
469 		s->d1->r_msg_hdr.type = msg_hdr->type;
470 		s->d1->r_msg_hdr.seq = msg_hdr->seq;
471 	} else if (msg_len != s->d1->r_msg_hdr.msg_len) {
472 		/*
473 		 * They must be playing with us! BTW, failure to enforce
474 		 * upper limit would open possibility for buffer overrun.
475 		 */
476 		SSLerror(s, SSL_R_EXCESSIVE_MESSAGE_SIZE);
477 		return SSL_AD_ILLEGAL_PARAMETER;
478 	}
479 
480 	return 0; /* no error */
481 }
482 
483 static int
dtls1_retrieve_buffered_fragment(SSL * s,long max,int * ok)484 dtls1_retrieve_buffered_fragment(SSL *s, long max, int *ok)
485 {
486 	/*
487 	 * (0) check whether the desired fragment is available
488 	 * if so:
489 	 * (1) copy over the fragment to s->internal->init_buf->data[]
490 	 * (2) update s->internal->init_num
491 	 */
492 	pitem *item;
493 	hm_fragment *frag;
494 	int al;
495 
496 	*ok = 0;
497 	item = pqueue_peek(s->d1->buffered_messages);
498 	if (item == NULL)
499 		return 0;
500 
501 	frag = (hm_fragment *)item->data;
502 
503 	/* Don't return if reassembly still in progress */
504 	if (frag->reassembly != NULL)
505 		return 0;
506 
507 	if (s->d1->handshake_read_seq == frag->msg_header.seq) {
508 		unsigned long frag_len = frag->msg_header.frag_len;
509 		pqueue_pop(s->d1->buffered_messages);
510 
511 		al = dtls1_preprocess_fragment(s, &frag->msg_header, max);
512 
513 		if (al == 0) /* no alert */
514 		{
515 			unsigned char *p = (unsigned char *)s->internal->init_buf->data + DTLS1_HM_HEADER_LENGTH;
516 			memcpy(&p[frag->msg_header.frag_off],
517 			    frag->fragment, frag->msg_header.frag_len);
518 		}
519 
520 		dtls1_hm_fragment_free(frag);
521 		pitem_free(item);
522 
523 		if (al == 0) {
524 			*ok = 1;
525 			return frag_len;
526 		}
527 
528 		ssl3_send_alert(s, SSL3_AL_FATAL, al);
529 		s->internal->init_num = 0;
530 		*ok = 0;
531 		return -1;
532 	} else
533 		return 0;
534 }
535 
536 /*
537  * dtls1_max_handshake_message_len returns the maximum number of bytes
538  * permitted in a DTLS handshake message for |s|. The minimum is 16KB,
539  * but may be greater if the maximum certificate list size requires it.
540  */
541 static unsigned long
dtls1_max_handshake_message_len(const SSL * s)542 dtls1_max_handshake_message_len(const SSL *s)
543 {
544 	unsigned long max_len;
545 
546 	max_len = DTLS1_HM_HEADER_LENGTH + SSL3_RT_MAX_ENCRYPTED_LENGTH;
547 	if (max_len < (unsigned long)s->internal->max_cert_list)
548 		return s->internal->max_cert_list;
549 	return max_len;
550 }
551 
552 static int
dtls1_reassemble_fragment(SSL * s,struct hm_header_st * msg_hdr,int * ok)553 dtls1_reassemble_fragment(SSL *s, struct hm_header_st* msg_hdr, int *ok)
554 {
555 	hm_fragment *frag = NULL;
556 	pitem *item = NULL;
557 	int i = -1, is_complete;
558 	unsigned char seq64be[8];
559 	unsigned long frag_len = msg_hdr->frag_len;
560 
561 	if ((msg_hdr->frag_off + frag_len) > msg_hdr->msg_len ||
562 	    msg_hdr->msg_len > dtls1_max_handshake_message_len(s))
563 		goto err;
564 
565 	if (frag_len == 0) {
566 		i = DTLS1_HM_FRAGMENT_RETRY;
567 		goto err;
568 	}
569 
570 	/* Try to find item in queue */
571 	memset(seq64be, 0, sizeof(seq64be));
572 	seq64be[6] = (unsigned char)(msg_hdr->seq >> 8);
573 	seq64be[7] = (unsigned char)msg_hdr->seq;
574 	item = pqueue_find(s->d1->buffered_messages, seq64be);
575 
576 	if (item == NULL) {
577 		frag = dtls1_hm_fragment_new(msg_hdr->msg_len, 1);
578 		if (frag == NULL)
579 			goto err;
580 		memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
581 		frag->msg_header.frag_len = frag->msg_header.msg_len;
582 		frag->msg_header.frag_off = 0;
583 	} else {
584 		frag = (hm_fragment*)item->data;
585 		if (frag->msg_header.msg_len != msg_hdr->msg_len) {
586 			item = NULL;
587 			frag = NULL;
588 			goto err;
589 		}
590 	}
591 
592 	/*
593 	 * If message is already reassembled, this must be a
594 	 * retransmit and can be dropped.
595 	 */
596 	if (frag->reassembly == NULL) {
597 		unsigned char devnull [256];
598 
599 		while (frag_len) {
600 			i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE,
601 			    devnull, frag_len > sizeof(devnull) ?
602 			    sizeof(devnull) : frag_len, 0);
603 			if (i <= 0)
604 				goto err;
605 			frag_len -= i;
606 		}
607 		i = DTLS1_HM_FRAGMENT_RETRY;
608 		goto err;
609 	}
610 
611 	/* read the body of the fragment (header has already been read */
612 	i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE,
613 	    frag->fragment + msg_hdr->frag_off, frag_len, 0);
614 	if (i <= 0 || (unsigned long)i != frag_len)
615 		goto err;
616 
617 	RSMBLY_BITMASK_MARK(frag->reassembly, (long)msg_hdr->frag_off,
618 	    (long)(msg_hdr->frag_off + frag_len));
619 
620 	RSMBLY_BITMASK_IS_COMPLETE(frag->reassembly, (long)msg_hdr->msg_len,
621 	    is_complete);
622 
623 	if (is_complete) {
624 		free(frag->reassembly);
625 		frag->reassembly = NULL;
626 	}
627 
628 	if (item == NULL) {
629 		memset(seq64be, 0, sizeof(seq64be));
630 		seq64be[6] = (unsigned char)(msg_hdr->seq >> 8);
631 		seq64be[7] = (unsigned char)(msg_hdr->seq);
632 
633 		item = pitem_new(seq64be, frag);
634 		if (item == NULL) {
635 			i = -1;
636 			goto err;
637 		}
638 
639 		pqueue_insert(s->d1->buffered_messages, item);
640 	}
641 
642 	return DTLS1_HM_FRAGMENT_RETRY;
643 
644  err:
645 	if (item == NULL && frag != NULL)
646 		dtls1_hm_fragment_free(frag);
647 	*ok = 0;
648 	return i;
649 }
650 
651 
652 static int
dtls1_process_out_of_seq_message(SSL * s,struct hm_header_st * msg_hdr,int * ok)653 dtls1_process_out_of_seq_message(SSL *s, struct hm_header_st* msg_hdr, int *ok)
654 {
655 	int i = -1;
656 	hm_fragment *frag = NULL;
657 	pitem *item = NULL;
658 	unsigned char seq64be[8];
659 	unsigned long frag_len = msg_hdr->frag_len;
660 
661 	if ((msg_hdr->frag_off + frag_len) > msg_hdr->msg_len)
662 		goto err;
663 
664 	/* Try to find item in queue, to prevent duplicate entries */
665 	memset(seq64be, 0, sizeof(seq64be));
666 	seq64be[6] = (unsigned char) (msg_hdr->seq >> 8);
667 	seq64be[7] = (unsigned char) msg_hdr->seq;
668 	item = pqueue_find(s->d1->buffered_messages, seq64be);
669 
670 	/*
671 	 * If we already have an entry and this one is a fragment,
672 	 * don't discard it and rather try to reassemble it.
673 	 */
674 	if (item != NULL && frag_len < msg_hdr->msg_len)
675 		item = NULL;
676 
677 	/*
678 	 * Discard the message if sequence number was already there, is
679 	 * too far in the future, already in the queue or if we received
680 	 * a FINISHED before the SERVER_HELLO, which then must be a stale
681 	 * retransmit.
682 	 */
683 	if (msg_hdr->seq <= s->d1->handshake_read_seq ||
684 	    msg_hdr->seq > s->d1->handshake_read_seq + 10 || item != NULL ||
685 	    (s->d1->handshake_read_seq == 0 &&
686 	    msg_hdr->type == SSL3_MT_FINISHED)) {
687 		unsigned char devnull [256];
688 
689 		while (frag_len) {
690 			i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE,
691 			    devnull, frag_len > sizeof(devnull) ?
692 			    sizeof(devnull) : frag_len, 0);
693 			if (i <= 0)
694 				goto err;
695 			frag_len -= i;
696 		}
697 	} else {
698 		if (frag_len < msg_hdr->msg_len)
699 			return dtls1_reassemble_fragment(s, msg_hdr, ok);
700 
701 		if (frag_len > dtls1_max_handshake_message_len(s))
702 			goto err;
703 
704 		frag = dtls1_hm_fragment_new(frag_len, 0);
705 		if (frag == NULL)
706 			goto err;
707 
708 		memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
709 
710 		if (frag_len) {
711 			/* read the body of the fragment (header has already been read */
712 			i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE,
713 			    frag->fragment, frag_len, 0);
714 			if (i <= 0 || (unsigned long)i != frag_len)
715 				goto err;
716 		}
717 
718 		memset(seq64be, 0, sizeof(seq64be));
719 		seq64be[6] = (unsigned char)(msg_hdr->seq >> 8);
720 		seq64be[7] = (unsigned char)(msg_hdr->seq);
721 
722 		item = pitem_new(seq64be, frag);
723 		if (item == NULL)
724 			goto err;
725 
726 		pqueue_insert(s->d1->buffered_messages, item);
727 	}
728 
729 	return DTLS1_HM_FRAGMENT_RETRY;
730 
731  err:
732 	if (item == NULL && frag != NULL)
733 		dtls1_hm_fragment_free(frag);
734 	*ok = 0;
735 	return i;
736 }
737 
738 
739 static long
dtls1_get_message_fragment(SSL * s,int st1,int stn,long max,int * ok)740 dtls1_get_message_fragment(SSL *s, int st1, int stn, long max, int *ok)
741 {
742 	unsigned char wire[DTLS1_HM_HEADER_LENGTH];
743 	unsigned long len, frag_off, frag_len;
744 	struct hm_header_st msg_hdr;
745 	int i, al;
746 	CBS cbs;
747 
748  again:
749 	/* see if we have the required fragment already */
750 	if ((frag_len = dtls1_retrieve_buffered_fragment(s, max, ok)) || *ok) {
751 		if (*ok)
752 			s->internal->init_num = frag_len;
753 		return frag_len;
754 	}
755 
756 	/* read handshake message header */
757 	i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE, wire,
758 	    DTLS1_HM_HEADER_LENGTH, 0);
759 	if (i <= 0) {
760 	 	/* nbio, or an error */
761 		s->internal->rwstate = SSL_READING;
762 		*ok = 0;
763 		return i;
764 	}
765 
766 	CBS_init(&cbs, wire, i);
767 	if (!dtls1_get_message_header(&cbs, &msg_hdr)) {
768 		/* Handshake fails if message header is incomplete. */
769 		al = SSL_AD_UNEXPECTED_MESSAGE;
770 		SSLerror(s, SSL_R_UNEXPECTED_MESSAGE);
771 		goto fatal_err;
772 	}
773 
774 	/*
775 	 * if this is a future (or stale) message it gets buffered
776 	 * (or dropped)--no further processing at this time
777 	 * While listening, we accept seq 1 (ClientHello with cookie)
778 	 * although we're still expecting seq 0 (ClientHello)
779 	 */
780 	if (msg_hdr.seq != s->d1->handshake_read_seq &&
781 	    !(s->d1->listen && msg_hdr.seq == 1))
782 		return dtls1_process_out_of_seq_message(s, &msg_hdr, ok);
783 
784 	len = msg_hdr.msg_len;
785 	frag_off = msg_hdr.frag_off;
786 	frag_len = msg_hdr.frag_len;
787 
788 	if (frag_len && frag_len < len)
789 		return dtls1_reassemble_fragment(s, &msg_hdr, ok);
790 
791 	if (!s->server && s->d1->r_msg_hdr.frag_off == 0 &&
792 	    wire[0] == SSL3_MT_HELLO_REQUEST) {
793 		/*
794 		 * The server may always send 'Hello Request' messages --
795 		 * we are doing a handshake anyway now, so ignore them
796 		 * if their format is correct. Does not count for
797 		 * 'Finished' MAC.
798 		 */
799 		if (wire[1] == 0 && wire[2] == 0 && wire[3] == 0) {
800 			if (s->internal->msg_callback)
801 				s->internal->msg_callback(0, s->version,
802 				    SSL3_RT_HANDSHAKE, wire,
803 				    DTLS1_HM_HEADER_LENGTH, s,
804 				    s->internal->msg_callback_arg);
805 
806 			s->internal->init_num = 0;
807 			goto again;
808 		}
809 		else /* Incorrectly formated Hello request */
810 		{
811 			al = SSL_AD_UNEXPECTED_MESSAGE;
812 			SSLerror(s, SSL_R_UNEXPECTED_MESSAGE);
813 			goto fatal_err;
814 		}
815 	}
816 
817 	if ((al = dtls1_preprocess_fragment(s, &msg_hdr, max)))
818 		goto fatal_err;
819 
820 	/* XDTLS:  ressurect this when restart is in place */
821 	s->s3->hs.state = stn;
822 
823 	if (frag_len > 0) {
824 		unsigned char *p = (unsigned char *)s->internal->init_buf->data + DTLS1_HM_HEADER_LENGTH;
825 
826 		i = s->method->ssl_read_bytes(s, SSL3_RT_HANDSHAKE,
827 		    &p[frag_off], frag_len, 0);
828 		/* XDTLS:  fix this--message fragments cannot span multiple packets */
829 		if (i <= 0) {
830 			s->internal->rwstate = SSL_READING;
831 			*ok = 0;
832 			return i;
833 		}
834 	} else
835 		i = 0;
836 
837 	/*
838 	 * XDTLS:  an incorrectly formatted fragment should cause the
839 	 * handshake to fail
840 	 */
841 	if (i != (int)frag_len) {
842 		al = SSL_AD_ILLEGAL_PARAMETER;
843 		SSLerror(s, SSL_R_SSLV3_ALERT_ILLEGAL_PARAMETER);
844 		goto fatal_err;
845 	}
846 
847 	/*
848 	 * Note that s->internal->init_num is *not* used as current offset in
849 	 * s->internal->init_buf->data, but as a counter summing up fragments'
850 	 * lengths: as soon as they sum up to handshake packet
851 	 * length, we assume we have got all the fragments.
852 	 */
853 	s->internal->init_num = frag_len;
854 	*ok = 1;
855 	return frag_len;
856 
857  fatal_err:
858 	ssl3_send_alert(s, SSL3_AL_FATAL, al);
859 	s->internal->init_num = 0;
860 
861 	*ok = 0;
862 	return (-1);
863 }
864 
865 int
dtls1_read_failed(SSL * s,int code)866 dtls1_read_failed(SSL *s, int code)
867 {
868 	if (code > 0) {
869 #ifdef DEBUG
870 		fprintf(stderr, "invalid state reached %s:%d",
871 		    __FILE__, __LINE__);
872 #endif
873 		return 1;
874 	}
875 
876 	if (!dtls1_is_timer_expired(s)) {
877 		/*
878 		 * not a timeout, none of our business, let higher layers
879 		 * handle this.  in fact it's probably an error
880 		 */
881 		return code;
882 	}
883 
884 	if (!SSL_in_init(s))  /* done, no need to send a retransmit */
885 	{
886 		BIO_set_flags(SSL_get_rbio(s), BIO_FLAGS_READ);
887 		return code;
888 	}
889 
890 	return dtls1_handle_timeout(s);
891 }
892 
893 int
dtls1_get_queue_priority(unsigned short seq,int is_ccs)894 dtls1_get_queue_priority(unsigned short seq, int is_ccs)
895 {
896 	/*
897 	 * The index of the retransmission queue actually is the message
898 	 * sequence number, since the queue only contains messages of a
899 	 * single handshake. However, the ChangeCipherSpec has no message
900 	 * sequence number and so using only the sequence will result in
901 	 * the CCS and Finished having the same index. To prevent this, the
902 	 * sequence number is multiplied by 2. In case of a CCS 1 is
903 	 * subtracted.  This does not only differ CSS and Finished, it also
904 	 * maintains the order of the index (important for priority queues)
905 	 * and fits in the unsigned short variable.
906 	 */
907 	return seq * 2 - is_ccs;
908 }
909 
910 int
dtls1_retransmit_buffered_messages(SSL * s)911 dtls1_retransmit_buffered_messages(SSL *s)
912 {
913 	pqueue sent = s->d1->sent_messages;
914 	piterator iter;
915 	pitem *item;
916 	hm_fragment *frag;
917 	int found = 0;
918 
919 	iter = pqueue_iterator(sent);
920 
921 	for (item = pqueue_next(&iter); item != NULL;
922 	    item = pqueue_next(&iter)) {
923 		frag = (hm_fragment *)item->data;
924 		if (dtls1_retransmit_message(s,
925 		    (unsigned short)dtls1_get_queue_priority(
926 		    frag->msg_header.seq, frag->msg_header.is_ccs), 0,
927 		    &found) <= 0 && found) {
928 #ifdef DEBUG
929 			fprintf(stderr, "dtls1_retransmit_message() failed\n");
930 #endif
931 			return -1;
932 		}
933 	}
934 
935 	return 1;
936 }
937 
938 int
dtls1_buffer_message(SSL * s,int is_ccs)939 dtls1_buffer_message(SSL *s, int is_ccs)
940 {
941 	pitem *item;
942 	hm_fragment *frag;
943 	unsigned char seq64be[8];
944 
945 	/* Buffer the messsage in order to handle DTLS retransmissions. */
946 
947 	/*
948 	 * This function is called immediately after a message has
949 	 * been serialized
950 	 */
951 	OPENSSL_assert(s->internal->init_off == 0);
952 
953 	frag = dtls1_hm_fragment_new(s->internal->init_num, 0);
954 	if (frag == NULL)
955 		return 0;
956 
957 	memcpy(frag->fragment, s->internal->init_buf->data, s->internal->init_num);
958 
959 	OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
960 	    (is_ccs ? DTLS1_CCS_HEADER_LENGTH : DTLS1_HM_HEADER_LENGTH) ==
961 	    (unsigned int)s->internal->init_num);
962 
963 	frag->msg_header.msg_len = s->d1->w_msg_hdr.msg_len;
964 	frag->msg_header.seq = s->d1->w_msg_hdr.seq;
965 	frag->msg_header.type = s->d1->w_msg_hdr.type;
966 	frag->msg_header.frag_off = 0;
967 	frag->msg_header.frag_len = s->d1->w_msg_hdr.msg_len;
968 	frag->msg_header.is_ccs = is_ccs;
969 
970 	/* save current state*/
971 	frag->msg_header.saved_retransmit_state.session = s->session;
972 	frag->msg_header.saved_retransmit_state.epoch =
973 	    tls12_record_layer_write_epoch(s->internal->rl);
974 
975 	memset(seq64be, 0, sizeof(seq64be));
976 	seq64be[6] = (unsigned char)(dtls1_get_queue_priority(
977 	    frag->msg_header.seq, frag->msg_header.is_ccs) >> 8);
978 	seq64be[7] = (unsigned char)(dtls1_get_queue_priority(
979 	    frag->msg_header.seq, frag->msg_header.is_ccs));
980 
981 	item = pitem_new(seq64be, frag);
982 	if (item == NULL) {
983 		dtls1_hm_fragment_free(frag);
984 		return 0;
985 	}
986 
987 	pqueue_insert(s->d1->sent_messages, item);
988 	return 1;
989 }
990 
991 int
dtls1_retransmit_message(SSL * s,unsigned short seq,unsigned long frag_off,int * found)992 dtls1_retransmit_message(SSL *s, unsigned short seq, unsigned long frag_off,
993     int *found)
994 {
995 	int ret;
996 	/* XDTLS: for now assuming that read/writes are blocking */
997 	pitem *item;
998 	hm_fragment *frag;
999 	unsigned long header_length;
1000 	unsigned char seq64be[8];
1001 	struct dtls1_retransmit_state saved_state;
1002 
1003 	/*
1004 	  OPENSSL_assert(s->internal->init_num == 0);
1005 	  OPENSSL_assert(s->internal->init_off == 0);
1006 	 */
1007 
1008 	/* XDTLS:  the requested message ought to be found, otherwise error */
1009 	memset(seq64be, 0, sizeof(seq64be));
1010 	seq64be[6] = (unsigned char)(seq >> 8);
1011 	seq64be[7] = (unsigned char)seq;
1012 
1013 	item = pqueue_find(s->d1->sent_messages, seq64be);
1014 	if (item == NULL) {
1015 #ifdef DEBUG
1016 		fprintf(stderr, "retransmit:  message %d non-existent\n", seq);
1017 #endif
1018 		*found = 0;
1019 		return 0;
1020 	}
1021 
1022 	*found = 1;
1023 	frag = (hm_fragment *)item->data;
1024 
1025 	if (frag->msg_header.is_ccs)
1026 		header_length = DTLS1_CCS_HEADER_LENGTH;
1027 	else
1028 		header_length = DTLS1_HM_HEADER_LENGTH;
1029 
1030 	memcpy(s->internal->init_buf->data, frag->fragment,
1031 	    frag->msg_header.msg_len + header_length);
1032 	s->internal->init_num = frag->msg_header.msg_len + header_length;
1033 
1034 	dtls1_set_message_header_int(s, frag->msg_header.type,
1035 	    frag->msg_header.msg_len, frag->msg_header.seq, 0,
1036 	    frag->msg_header.frag_len);
1037 
1038 	/* save current state */
1039 	saved_state.session = s->session;
1040 	saved_state.epoch = tls12_record_layer_write_epoch(s->internal->rl);
1041 
1042 	s->d1->retransmitting = 1;
1043 
1044 	/* restore state in which the message was originally sent */
1045 	s->session = frag->msg_header.saved_retransmit_state.session;
1046 	if (!tls12_record_layer_use_write_epoch(s->internal->rl,
1047 	    frag->msg_header.saved_retransmit_state.epoch))
1048 		return 0;
1049 
1050 	ret = dtls1_do_write(s, frag->msg_header.is_ccs ?
1051 	    SSL3_RT_CHANGE_CIPHER_SPEC : SSL3_RT_HANDSHAKE);
1052 
1053 	/* restore current state */
1054 	s->session = saved_state.session;
1055 	if (!tls12_record_layer_use_write_epoch(s->internal->rl,
1056 	    saved_state.epoch))
1057 		return 0;
1058 
1059 	s->d1->retransmitting = 0;
1060 
1061 	(void)BIO_flush(SSL_get_wbio(s));
1062 	return ret;
1063 }
1064 
1065 /* call this function when the buffered messages are no longer needed */
1066 void
dtls1_clear_record_buffer(SSL * s)1067 dtls1_clear_record_buffer(SSL *s)
1068 {
1069 	hm_fragment *frag;
1070 	pitem *item;
1071 
1072 	for(item = pqueue_pop(s->d1->sent_messages); item != NULL;
1073 	    item = pqueue_pop(s->d1->sent_messages)) {
1074 		frag = item->data;
1075 		if (frag->msg_header.is_ccs)
1076 			tls12_record_layer_write_epoch_done(s->internal->rl,
1077 			    frag->msg_header.saved_retransmit_state.epoch);
1078 		dtls1_hm_fragment_free(frag);
1079 		pitem_free(item);
1080 	}
1081 }
1082 
1083 void
dtls1_set_message_header(SSL * s,unsigned char mt,unsigned long len,unsigned long frag_off,unsigned long frag_len)1084 dtls1_set_message_header(SSL *s, unsigned char mt, unsigned long len,
1085     unsigned long frag_off, unsigned long frag_len)
1086 {
1087 	/* Don't change sequence numbers while listening */
1088 	if (frag_off == 0 && !s->d1->listen) {
1089 		s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
1090 		s->d1->next_handshake_write_seq++;
1091 	}
1092 
1093 	dtls1_set_message_header_int(s, mt, len, s->d1->handshake_write_seq,
1094 	    frag_off, frag_len);
1095 }
1096 
1097 /* don't actually do the writing, wait till the MTU has been retrieved */
1098 void
dtls1_set_message_header_int(SSL * s,unsigned char mt,unsigned long len,unsigned short seq_num,unsigned long frag_off,unsigned long frag_len)1099 dtls1_set_message_header_int(SSL *s, unsigned char mt, unsigned long len,
1100     unsigned short seq_num, unsigned long frag_off, unsigned long frag_len)
1101 {
1102 	struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1103 
1104 	msg_hdr->type = mt;
1105 	msg_hdr->msg_len = len;
1106 	msg_hdr->seq = seq_num;
1107 	msg_hdr->frag_off = frag_off;
1108 	msg_hdr->frag_len = frag_len;
1109 }
1110 
1111 static void
dtls1_fix_message_header(SSL * s,unsigned long frag_off,unsigned long frag_len)1112 dtls1_fix_message_header(SSL *s, unsigned long frag_off, unsigned long frag_len)
1113 {
1114 	struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
1115 
1116 	msg_hdr->frag_off = frag_off;
1117 	msg_hdr->frag_len = frag_len;
1118 }
1119 
1120 static int
dtls1_write_message_header(const struct hm_header_st * msg_hdr,unsigned long frag_off,unsigned long frag_len,unsigned char * p)1121 dtls1_write_message_header(const struct hm_header_st *msg_hdr,
1122     unsigned long frag_off, unsigned long frag_len, unsigned char *p)
1123 {
1124 	CBB cbb;
1125 
1126 	/* We assume DTLS1_HM_HEADER_LENGTH bytes are available for now... */
1127 	if (!CBB_init_fixed(&cbb, p, DTLS1_HM_HEADER_LENGTH))
1128 		return 0;
1129 	if (!CBB_add_u8(&cbb, msg_hdr->type))
1130 		goto err;
1131 	if (!CBB_add_u24(&cbb, msg_hdr->msg_len))
1132 		goto err;
1133 	if (!CBB_add_u16(&cbb, msg_hdr->seq))
1134 		goto err;
1135 	if (!CBB_add_u24(&cbb, frag_off))
1136 		goto err;
1137 	if (!CBB_add_u24(&cbb, frag_len))
1138 		goto err;
1139 	if (!CBB_finish(&cbb, NULL, NULL))
1140 		goto err;
1141 
1142 	return 1;
1143 
1144  err:
1145 	CBB_cleanup(&cbb);
1146 	return 0;
1147 }
1148 
1149 unsigned int
dtls1_min_mtu(void)1150 dtls1_min_mtu(void)
1151 {
1152 	return (g_probable_mtu[(sizeof(g_probable_mtu) /
1153 	    sizeof(g_probable_mtu[0])) - 1]);
1154 }
1155 
1156 static unsigned int
dtls1_guess_mtu(unsigned int curr_mtu)1157 dtls1_guess_mtu(unsigned int curr_mtu)
1158 {
1159 	unsigned int i;
1160 
1161 	if (curr_mtu == 0)
1162 		return g_probable_mtu[0];
1163 
1164 	for (i = 0; i < sizeof(g_probable_mtu) / sizeof(g_probable_mtu[0]); i++)
1165 		if (curr_mtu > g_probable_mtu[i])
1166 			return g_probable_mtu[i];
1167 
1168 	return curr_mtu;
1169 }
1170 
1171 int
dtls1_get_message_header(CBS * header,struct hm_header_st * msg_hdr)1172 dtls1_get_message_header(CBS *header, struct hm_header_st *msg_hdr)
1173 {
1174 	uint32_t msg_len, frag_off, frag_len;
1175 	uint16_t seq;
1176 	uint8_t type;
1177 
1178 	memset(msg_hdr, 0, sizeof(*msg_hdr));
1179 
1180 	if (!CBS_get_u8(header, &type))
1181 		return 0;
1182 	if (!CBS_get_u24(header, &msg_len))
1183 		return 0;
1184 	if (!CBS_get_u16(header, &seq))
1185 		return 0;
1186 	if (!CBS_get_u24(header, &frag_off))
1187 		return 0;
1188 	if (!CBS_get_u24(header, &frag_len))
1189 		return 0;
1190 
1191 	msg_hdr->type = type;
1192 	msg_hdr->msg_len = msg_len;
1193 	msg_hdr->seq = seq;
1194 	msg_hdr->frag_off = frag_off;
1195 	msg_hdr->frag_len = frag_len;
1196 
1197 	return 1;
1198 }
1199