eb3af232c7e719171138696b96d7e5fd6449a5d1
[openssl.git] / ssl / d1_pkt.c
1 /* ssl/d1_pkt.c */
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 <stdio.h>
117 #include <errno.h>
118 #define USE_SOCKETS
119 #include "ssl_locl.h"
120 #include <openssl/evp.h>
121 #include <openssl/buffer.h>
122 #include <openssl/pqueue.h>
123 #include <openssl/rand.h>
124
125 /* mod 128 saturating subtract of two 64-bit values in big-endian order */
126 static int satsub64be(const unsigned char *v1,const unsigned char *v2)
127 {       int ret,sat,brw,i;
128
129         if (sizeof(long) == 8) do
130         {       const union { long one; char little; } is_endian = {1};
131                 long l;
132
133                 if (is_endian.little)                   break;
134                 /* not reached on little-endians */
135                 /* following test is redundant, because input is
136                  * always aligned, but I take no chances... */
137                 if (((size_t)v1|(size_t)v2)&0x7)        break;
138
139                 l  = *((long *)v1);
140                 l -= *((long *)v2);
141                 if (l>128)              return 128;
142                 else if (l<-128)        return -128;
143                 else                    return (int)l;
144         } while (0);
145
146         ret = (int)v1[7]-(int)v2[7];
147         sat = 0;
148         brw = ret>>8;   /* brw is either 0 or -1 */
149         if (ret & 0x80)
150         {       for (i=6;i>=0;i--)
151                 {       brw += (int)v1[i]-(int)v2[i];
152                         sat |= ~brw;
153                         brw >>= 8;
154                 }
155         }
156         else
157         {       for (i=6;i>=0;i--)
158                 {       brw += (int)v1[i]-(int)v2[i];
159                         sat |= brw;
160                         brw >>= 8;
161                 }
162         }
163         brw <<= 8;      /* brw is either 0 or -256 */
164
165         if (sat&0xff)   return brw | 0x80;
166         else            return brw + (ret&0xFF);
167 }
168
169 static int have_handshake_fragment(SSL *s, int type, unsigned char *buf, 
170         int len, int peek);
171 static int dtls1_record_replay_check(SSL *s, DTLS1_BITMAP *bitmap);
172 static void dtls1_record_bitmap_update(SSL *s, DTLS1_BITMAP *bitmap);
173 static DTLS1_BITMAP *dtls1_get_bitmap(SSL *s, SSL3_RECORD *rr, 
174     unsigned int *is_next_epoch);
175 #if 0
176 static int dtls1_record_needs_buffering(SSL *s, SSL3_RECORD *rr,
177         unsigned short *priority, unsigned long *offset);
178 #endif
179 static int dtls1_buffer_record(SSL *s, record_pqueue *q,
180         unsigned char *priority);
181 static int dtls1_process_record(SSL *s);
182 static void dtls1_clear_timeouts(SSL *s);
183
184 /* copy buffered record into SSL structure */
185 static int
186 dtls1_copy_record(SSL *s, pitem *item)
187     {
188     DTLS1_RECORD_DATA *rdata;
189
190     rdata = (DTLS1_RECORD_DATA *)item->data;
191     
192     if (s->s3->rbuf.buf != NULL)
193         OPENSSL_free(s->s3->rbuf.buf);
194     
195     s->packet = rdata->packet;
196     s->packet_length = rdata->packet_length;
197     memcpy(&(s->s3->rbuf), &(rdata->rbuf), sizeof(SSL3_BUFFER));
198     memcpy(&(s->s3->rrec), &(rdata->rrec), sizeof(SSL3_RECORD));
199     
200     return(1);
201     }
202
203
204 static int
205 dtls1_buffer_record(SSL *s, record_pqueue *queue, unsigned char *priority)
206         {
207         DTLS1_RECORD_DATA *rdata;
208         pitem *item;
209
210         rdata = OPENSSL_malloc(sizeof(DTLS1_RECORD_DATA));
211         item = pitem_new(priority, rdata);
212         if (rdata == NULL || item == NULL)
213                 {
214                 if (rdata != NULL) OPENSSL_free(rdata);
215                 if (item != NULL) pitem_free(item);
216                 
217                 SSLerr(SSL_F_DTLS1_BUFFER_RECORD, ERR_R_INTERNAL_ERROR);
218                 return(0);
219                 }
220         
221         rdata->packet = s->packet;
222         rdata->packet_length = s->packet_length;
223         memcpy(&(rdata->rbuf), &(s->s3->rbuf), sizeof(SSL3_BUFFER));
224         memcpy(&(rdata->rrec), &(s->s3->rrec), sizeof(SSL3_RECORD));
225
226         item->data = rdata;
227
228         /* insert should not fail, since duplicates are dropped */
229         if (pqueue_insert(queue->q, item) == NULL)
230                 {
231                 OPENSSL_free(rdata);
232                 pitem_free(item);
233                 return(0);
234                 }
235
236         s->packet = NULL;
237         s->packet_length = 0;
238         memset(&(s->s3->rbuf), 0, sizeof(SSL3_BUFFER));
239         memset(&(s->s3->rrec), 0, sizeof(SSL3_RECORD));
240         
241         if (!ssl3_setup_buffers(s))
242                 {
243                 SSLerr(SSL_F_DTLS1_BUFFER_RECORD, ERR_R_INTERNAL_ERROR);
244                 OPENSSL_free(rdata);
245                 pitem_free(item);
246                 return(0);
247                 }
248         
249         return(1);
250         }
251
252
253 static int
254 dtls1_retrieve_buffered_record(SSL *s, record_pqueue *queue)
255     {
256     pitem *item;
257
258     item = pqueue_pop(queue->q);
259     if (item)
260         {
261         dtls1_copy_record(s, item);
262
263         OPENSSL_free(item->data);
264                 pitem_free(item);
265
266         return(1);
267         }
268
269     return(0);
270     }
271
272
273 /* retrieve a buffered record that belongs to the new epoch, i.e., not processed 
274  * yet */
275 #define dtls1_get_unprocessed_record(s) \
276                    dtls1_retrieve_buffered_record((s), \
277                    &((s)->d1->unprocessed_rcds))
278
279 /* retrieve a buffered record that belongs to the current epoch, ie, processed */
280 #define dtls1_get_processed_record(s) \
281                    dtls1_retrieve_buffered_record((s), \
282                    &((s)->d1->processed_rcds))
283
284 static int
285 dtls1_process_buffered_records(SSL *s)
286     {
287     pitem *item;
288     
289     item = pqueue_peek(s->d1->unprocessed_rcds.q);
290     if (item)
291         {
292         DTLS1_RECORD_DATA *rdata;
293         rdata = (DTLS1_RECORD_DATA *)item->data;
294         
295         /* Check if epoch is current. */
296         if (s->d1->unprocessed_rcds.epoch != s->d1->r_epoch)
297             return(1);  /* Nothing to do. */
298         
299         /* Process all the records. */
300         while (pqueue_peek(s->d1->unprocessed_rcds.q))
301             {
302             dtls1_get_unprocessed_record(s);
303             if ( ! dtls1_process_record(s))
304                 return(0);
305             dtls1_buffer_record(s, &(s->d1->processed_rcds), 
306                 s->s3->rrec.seq_num);
307             }
308         }
309
310     /* sync epoch numbers once all the unprocessed records 
311      * have been processed */
312     s->d1->processed_rcds.epoch = s->d1->r_epoch;
313     s->d1->unprocessed_rcds.epoch = s->d1->r_epoch + 1;
314
315     return(1);
316     }
317
318
319 #if 0
320
321 static int
322 dtls1_get_buffered_record(SSL *s)
323         {
324         pitem *item;
325         PQ_64BIT priority = 
326                 (((PQ_64BIT)s->d1->handshake_read_seq) << 32) | 
327                 ((PQ_64BIT)s->d1->r_msg_hdr.frag_off);
328         
329         if ( ! SSL_in_init(s))  /* if we're not (re)negotiating, 
330                                                            nothing buffered */
331                 return 0;
332
333
334         item = pqueue_peek(s->d1->rcvd_records);
335         if (item && item->priority == priority)
336                 {
337                 /* Check if we've received the record of interest.  It must be
338                  * a handshake record, since data records as passed up without
339                  * buffering */
340                 DTLS1_RECORD_DATA *rdata;
341                 item = pqueue_pop(s->d1->rcvd_records);
342                 rdata = (DTLS1_RECORD_DATA *)item->data;
343                 
344                 if (s->s3->rbuf.buf != NULL)
345                         OPENSSL_free(s->s3->rbuf.buf);
346                 
347                 s->packet = rdata->packet;
348                 s->packet_length = rdata->packet_length;
349                 memcpy(&(s->s3->rbuf), &(rdata->rbuf), sizeof(SSL3_BUFFER));
350                 memcpy(&(s->s3->rrec), &(rdata->rrec), sizeof(SSL3_RECORD));
351                 
352                 OPENSSL_free(item->data);
353                 pitem_free(item);
354                 
355                 /* s->d1->next_expected_seq_num++; */
356                 return(1);
357                 }
358         
359         return 0;
360         }
361
362 #endif
363
364 static int
365 dtls1_process_record(SSL *s)
366 {
367         int i,al;
368         int clear=0;
369         int enc_err;
370         SSL_SESSION *sess;
371         SSL3_RECORD *rr;
372         unsigned int mac_size;
373         unsigned char md[EVP_MAX_MD_SIZE];
374
375
376         rr= &(s->s3->rrec);
377         sess = s->session;
378
379         /* At this point, s->packet_length == SSL3_RT_HEADER_LNGTH + rr->length,
380          * and we have that many bytes in s->packet
381          */
382         rr->input= &(s->packet[DTLS1_RT_HEADER_LENGTH]);
383
384         /* ok, we can now read from 's->packet' data into 'rr'
385          * rr->input points at rr->length bytes, which
386          * need to be copied into rr->data by either
387          * the decryption or by the decompression
388          * When the data is 'copied' into the rr->data buffer,
389          * rr->input will be pointed at the new buffer */ 
390
391         /* We now have - encrypted [ MAC [ compressed [ plain ] ] ]
392          * rr->length bytes of encrypted compressed stuff. */
393
394         /* check is not needed I believe */
395         if (rr->length > SSL3_RT_MAX_ENCRYPTED_LENGTH)
396                 {
397                 al=SSL_AD_RECORD_OVERFLOW;
398                 SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_ENCRYPTED_LENGTH_TOO_LONG);
399                 goto f_err;
400                 }
401
402         /* decrypt in place in 'rr->input' */
403         rr->data=rr->input;
404
405         enc_err = s->method->ssl3_enc->enc(s,0);
406         if (enc_err <= 0)
407                 {
408                 if (enc_err == 0)
409                         /* SSLerr() and ssl3_send_alert() have been called */
410                         goto err;
411
412                 /* otherwise enc_err == -1 */
413                 goto decryption_failed_or_bad_record_mac;
414                 }
415
416 #ifdef TLS_DEBUG
417 printf("dec %d\n",rr->length);
418 { unsigned int z; for (z=0; z<rr->length; z++) printf("%02X%c",rr->data[z],((z+1)%16)?' ':'\n'); }
419 printf("\n");
420 #endif
421
422         /* r->length is now the compressed data plus mac */
423         if (    (sess == NULL) ||
424                 (s->enc_read_ctx == NULL) ||
425                 (s->read_hash == NULL))
426         clear=1;
427
428         if (!clear)
429                 {
430                 mac_size=EVP_MD_CTX_size(s->read_hash);
431
432                 if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH+mac_size)
433                         {
434 #if 0 /* OK only for stream ciphers (then rr->length is visible from ciphertext anyway) */
435                         al=SSL_AD_RECORD_OVERFLOW;
436                         SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_PRE_MAC_LENGTH_TOO_LONG);
437                         goto f_err;
438 #else
439                         goto decryption_failed_or_bad_record_mac;
440 #endif                  
441                         }
442                 /* check the MAC for rr->input (it's in mac_size bytes at the tail) */
443                 if (rr->length < mac_size)
444                         {
445 #if 0 /* OK only for stream ciphers */
446                         al=SSL_AD_DECODE_ERROR;
447                         SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_LENGTH_TOO_SHORT);
448                         goto f_err;
449 #else
450                         goto decryption_failed_or_bad_record_mac;
451 #endif
452                         }
453                 rr->length-=mac_size;
454                 i=s->method->ssl3_enc->mac(s,md,0);
455                 if (memcmp(md,&(rr->data[rr->length]),mac_size) != 0)
456                         {
457                         goto decryption_failed_or_bad_record_mac;
458                         }
459                 }
460
461         /* r->length is now just compressed */
462         if (s->expand != NULL)
463                 {
464                 if (rr->length > SSL3_RT_MAX_COMPRESSED_LENGTH)
465                         {
466                         al=SSL_AD_RECORD_OVERFLOW;
467                         SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_COMPRESSED_LENGTH_TOO_LONG);
468                         goto f_err;
469                         }
470                 if (!ssl3_do_uncompress(s))
471                         {
472                         al=SSL_AD_DECOMPRESSION_FAILURE;
473                         SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_BAD_DECOMPRESSION);
474                         goto f_err;
475                         }
476                 }
477
478         if (rr->length > SSL3_RT_MAX_PLAIN_LENGTH)
479                 {
480                 al=SSL_AD_RECORD_OVERFLOW;
481                 SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_DATA_LENGTH_TOO_LONG);
482                 goto f_err;
483                 }
484
485         rr->off=0;
486         /* So at this point the following is true
487          * ssl->s3->rrec.type   is the type of record
488          * ssl->s3->rrec.length == number of bytes in record
489          * ssl->s3->rrec.off    == offset to first valid byte
490          * ssl->s3->rrec.data   == where to take bytes from, increment
491          *                         after use :-).
492          */
493
494         /* we have pulled in a full packet so zero things */
495         s->packet_length=0;
496         dtls1_record_bitmap_update(s, &(s->d1->bitmap));/* Mark receipt of record. */
497         return(1);
498
499 decryption_failed_or_bad_record_mac:
500         /* Separate 'decryption_failed' alert was introduced with TLS 1.0,
501          * SSL 3.0 only has 'bad_record_mac'.  But unless a decryption
502          * failure is directly visible from the ciphertext anyway,
503          * we should not reveal which kind of error occured -- this
504          * might become visible to an attacker (e.g. via logfile) */
505         al=SSL_AD_BAD_RECORD_MAC;
506         SSLerr(SSL_F_DTLS1_PROCESS_RECORD,SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC);
507 f_err:
508         ssl3_send_alert(s,SSL3_AL_FATAL,al);
509 err:
510         return(0);
511 }
512
513
514 /* Call this to get a new input record.
515  * It will return <= 0 if more data is needed, normally due to an error
516  * or non-blocking IO.
517  * When it finishes, one packet has been decoded and can be found in
518  * ssl->s3->rrec.type    - is the type of record
519  * ssl->s3->rrec.data,   - data
520  * ssl->s3->rrec.length, - number of bytes
521  */
522 /* used only by dtls1_read_bytes */
523 int dtls1_get_record(SSL *s)
524         {
525         int ssl_major,ssl_minor,al;
526         int i,n;
527         SSL3_RECORD *rr;
528         SSL_SESSION *sess;
529         unsigned char *p;
530         unsigned short version;
531         DTLS1_BITMAP *bitmap;
532         unsigned int is_next_epoch;
533
534         rr= &(s->s3->rrec);
535         sess=s->session;
536
537         /* The epoch may have changed.  If so, process all the
538          * pending records.  This is a non-blocking operation. */
539         if ( ! dtls1_process_buffered_records(s))
540             return 0;
541
542         /* if we're renegotiating, then there may be buffered records */
543         if (dtls1_get_processed_record(s))
544                 return 1;
545
546         /* get something from the wire */
547 again:
548         /* check if we have the header */
549         if (    (s->rstate != SSL_ST_READ_BODY) ||
550                 (s->packet_length < DTLS1_RT_HEADER_LENGTH)) 
551                 {
552                 n=ssl3_read_n(s, DTLS1_RT_HEADER_LENGTH, s->s3->rbuf.len, 0);
553                 /* read timeout is handled by dtls1_read_bytes */
554                 if (n <= 0) return(n); /* error or non-blocking */
555
556                 OPENSSL_assert(s->packet_length == DTLS1_RT_HEADER_LENGTH);
557
558                 s->rstate=SSL_ST_READ_BODY;
559
560                 p=s->packet;
561
562                 /* Pull apart the header into the DTLS1_RECORD */
563                 rr->type= *(p++);
564                 ssl_major= *(p++);
565                 ssl_minor= *(p++);
566                 version=(ssl_major<<8)|ssl_minor;
567
568                 /* sequence number is 64 bits, with top 2 bytes = epoch */ 
569                 n2s(p,rr->epoch);
570
571                 memcpy(&(s->s3->read_sequence[2]), p, 6);
572                 p+=6;
573
574                 n2s(p,rr->length);
575
576                 /* Lets check version */
577                 if (!s->first_packet)
578                         {
579                         if (version != s->version)
580                                 {
581                                 SSLerr(SSL_F_DTLS1_GET_RECORD,SSL_R_WRONG_VERSION_NUMBER);
582                                 /* Send back error using their
583                                  * version number :-) */
584                                 s->version=version;
585                                 al=SSL_AD_PROTOCOL_VERSION;
586                                 goto f_err;
587                                 }
588                         }
589
590                 if ((version & 0xff00) != (DTLS1_VERSION & 0xff00))
591                         {
592                         SSLerr(SSL_F_DTLS1_GET_RECORD,SSL_R_WRONG_VERSION_NUMBER);
593                         goto err;
594                         }
595
596                 if (rr->length > SSL3_RT_MAX_ENCRYPTED_LENGTH)
597                         {
598                         al=SSL_AD_RECORD_OVERFLOW;
599                         SSLerr(SSL_F_DTLS1_GET_RECORD,SSL_R_PACKET_LENGTH_TOO_LONG);
600                         goto f_err;
601                         }
602
603                 /* now s->rstate == SSL_ST_READ_BODY */
604                 }
605
606         /* s->rstate == SSL_ST_READ_BODY, get and decode the data */
607
608         if (rr->length > s->packet_length-DTLS1_RT_HEADER_LENGTH)
609                 {
610                 /* now s->packet_length == DTLS1_RT_HEADER_LENGTH */
611                 i=rr->length;
612                 n=ssl3_read_n(s,i,i,1);
613                 if (n <= 0) return(n); /* error or non-blocking io */
614
615                 /* this packet contained a partial record, dump it */
616                 if ( n != i)
617                         {
618                         s->packet_length = 0;
619                         goto again;
620                         }
621
622                 /* now n == rr->length,
623                  * and s->packet_length == DTLS1_RT_HEADER_LENGTH + rr->length */
624                 }
625         s->rstate=SSL_ST_READ_HEADER; /* set state for later operations */
626
627         /* match epochs.  NULL means the packet is dropped on the floor */
628         bitmap = dtls1_get_bitmap(s, rr, &is_next_epoch);
629         if ( bitmap == NULL)
630                 {
631                 s->packet_length = 0;  /* dump this record */
632                 goto again;   /* get another record */
633                 }
634
635         /* check whether this is a repeat, or aged record */
636         if ( ! dtls1_record_replay_check(s, bitmap))
637                 {
638                 s->packet_length=0; /* dump this record */
639                 goto again;     /* get another record */
640                 }
641
642         /* just read a 0 length packet */
643         if (rr->length == 0) goto again;
644
645         /* If this record is from the next epoch (either HM or ALERT),
646          * buffer it since it cannot be processed at this time. Records
647          * from the next epoch are marked as received even though they
648          * are not processed, so as to prevent any potential resource
649          * DoS attack */
650         if (is_next_epoch)
651                 {
652                 dtls1_record_bitmap_update(s, bitmap);
653                 dtls1_buffer_record(s, &(s->d1->unprocessed_rcds), rr->seq_num);
654                 s->packet_length = 0;
655                 goto again;
656                 }
657
658         if ( ! dtls1_process_record(s))
659                 return(0);
660
661         dtls1_clear_timeouts(s);  /* done waiting */
662         return(1);
663
664 f_err:
665         ssl3_send_alert(s,SSL3_AL_FATAL,al);
666 err:
667         return(0);
668         }
669
670 /* Return up to 'len' payload bytes received in 'type' records.
671  * 'type' is one of the following:
672  *
673  *   -  SSL3_RT_HANDSHAKE (when ssl3_get_message calls us)
674  *   -  SSL3_RT_APPLICATION_DATA (when ssl3_read calls us)
675  *   -  0 (during a shutdown, no data has to be returned)
676  *
677  * If we don't have stored data to work from, read a SSL/TLS record first
678  * (possibly multiple records if we still don't have anything to return).
679  *
680  * This function must handle any surprises the peer may have for us, such as
681  * Alert records (e.g. close_notify), ChangeCipherSpec records (not really
682  * a surprise, but handled as if it were), or renegotiation requests.
683  * Also if record payloads contain fragments too small to process, we store
684  * them until there is enough for the respective protocol (the record protocol
685  * may use arbitrary fragmentation and even interleaving):
686  *     Change cipher spec protocol
687  *             just 1 byte needed, no need for keeping anything stored
688  *     Alert protocol
689  *             2 bytes needed (AlertLevel, AlertDescription)
690  *     Handshake protocol
691  *             4 bytes needed (HandshakeType, uint24 length) -- we just have
692  *             to detect unexpected Client Hello and Hello Request messages
693  *             here, anything else is handled by higher layers
694  *     Application data protocol
695  *             none of our business
696  */
697 int dtls1_read_bytes(SSL *s, int type, unsigned char *buf, int len, int peek)
698         {
699         int al,i,j,ret;
700         unsigned int n;
701         SSL3_RECORD *rr;
702         void (*cb)(const SSL *ssl,int type2,int val)=NULL;
703
704         if (s->s3->rbuf.buf == NULL) /* Not initialized yet */
705                 if (!ssl3_setup_buffers(s))
706                         return(-1);
707
708     /* XXX: check what the second '&& type' is about */
709         if ((type && (type != SSL3_RT_APPLICATION_DATA) && 
710                 (type != SSL3_RT_HANDSHAKE) && type) ||
711             (peek && (type != SSL3_RT_APPLICATION_DATA)))
712                 {
713                 SSLerr(SSL_F_DTLS1_READ_BYTES, ERR_R_INTERNAL_ERROR);
714                 return -1;
715                 }
716
717         /* check whether there's a handshake message (client hello?) waiting */
718         if ( (ret = have_handshake_fragment(s, type, buf, len, peek)))
719                 return ret;
720
721         /* Now s->d1->handshake_fragment_len == 0 if type == SSL3_RT_HANDSHAKE. */
722
723         if (!s->in_handshake && SSL_in_init(s))
724                 {
725                 /* type == SSL3_RT_APPLICATION_DATA */
726                 i=s->handshake_func(s);
727                 if (i < 0) return(i);
728                 if (i == 0)
729                         {
730                         SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_SSL_HANDSHAKE_FAILURE);
731                         return(-1);
732                         }
733                 }
734
735 start:
736         s->rwstate=SSL_NOTHING;
737
738         /* s->s3->rrec.type         - is the type of record
739          * s->s3->rrec.data,    - data
740          * s->s3->rrec.off,     - offset into 'data' for next read
741          * s->s3->rrec.length,  - number of bytes. */
742         rr = &(s->s3->rrec);
743
744         /* get new packet if necessary */
745         if ((rr->length == 0) || (s->rstate == SSL_ST_READ_BODY))
746                 {
747                 ret=dtls1_get_record(s);
748                 if (ret <= 0) 
749                         {
750                         ret = dtls1_read_failed(s, ret);
751                         /* anything other than a timeout is an error */
752                         if (ret <= 0)  
753                                 return(ret);
754                         else
755                                 goto start;
756                         }
757                 }
758
759         /* we now have a packet which can be read and processed */
760
761         if (s->s3->change_cipher_spec /* set when we receive ChangeCipherSpec,
762                                        * reset by ssl3_get_finished */
763                 && (rr->type != SSL3_RT_HANDSHAKE))
764                 {
765                 al=SSL_AD_UNEXPECTED_MESSAGE;
766                 SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_DATA_BETWEEN_CCS_AND_FINISHED);
767                 goto err;
768                 }
769
770         /* If the other end has shut down, throw anything we read away
771          * (even in 'peek' mode) */
772         if (s->shutdown & SSL_RECEIVED_SHUTDOWN)
773                 {
774                 rr->length=0;
775                 s->rwstate=SSL_NOTHING;
776                 return(0);
777                 }
778
779
780         if (type == rr->type) /* SSL3_RT_APPLICATION_DATA or SSL3_RT_HANDSHAKE */
781                 {
782                 /* make sure that we are not getting application data when we
783                  * are doing a handshake for the first time */
784                 if (SSL_in_init(s) && (type == SSL3_RT_APPLICATION_DATA) &&
785                         (s->enc_read_ctx == NULL))
786                         {
787                         al=SSL_AD_UNEXPECTED_MESSAGE;
788                         SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_APP_DATA_IN_HANDSHAKE);
789                         goto f_err;
790                         }
791
792                 if (len <= 0) return(len);
793
794                 if ((unsigned int)len > rr->length)
795                         n = rr->length;
796                 else
797                         n = (unsigned int)len;
798
799                 memcpy(buf,&(rr->data[rr->off]),n);
800                 if (!peek)
801                         {
802                         rr->length-=n;
803                         rr->off+=n;
804                         if (rr->length == 0)
805                                 {
806                                 s->rstate=SSL_ST_READ_HEADER;
807                                 rr->off=0;
808                                 }
809                         }
810                 return(n);
811                 }
812
813
814         /* If we get here, then type != rr->type; if we have a handshake
815          * message, then it was unexpected (Hello Request or Client Hello). */
816
817         /* In case of record types for which we have 'fragment' storage,
818          * fill that so that we can process the data at a fixed place.
819          */
820                 {
821                 unsigned int k, dest_maxlen = 0;
822                 unsigned char *dest = NULL;
823                 unsigned int *dest_len = NULL;
824
825                 if (rr->type == SSL3_RT_HANDSHAKE)
826                         {
827                         dest_maxlen = sizeof s->d1->handshake_fragment;
828                         dest = s->d1->handshake_fragment;
829                         dest_len = &s->d1->handshake_fragment_len;
830                         }
831                 else if (rr->type == SSL3_RT_ALERT)
832                         {
833                         dest_maxlen = sizeof(s->d1->alert_fragment);
834                         dest = s->d1->alert_fragment;
835                         dest_len = &s->d1->alert_fragment_len;
836                         }
837                 /* else it's a CCS message, or it's wrong */
838                 else if (rr->type != SSL3_RT_CHANGE_CIPHER_SPEC)
839                         {
840                           /* Not certain if this is the right error handling */
841                           al=SSL_AD_UNEXPECTED_MESSAGE;
842                           SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_UNEXPECTED_RECORD);
843                           goto f_err;
844                         }
845
846
847                 if (dest_maxlen > 0)
848                         {
849             /* XDTLS:  In a pathalogical case, the Client Hello
850              *  may be fragmented--don't always expect dest_maxlen bytes */
851                         if ( rr->length < dest_maxlen)
852                                 {
853 #ifdef DTLS1_AD_MISSING_HANDSHAKE_MESSAGE
854                                 /*
855                                  * for normal alerts rr->length is 2, while
856                                  * dest_maxlen is 7 if we were to handle this
857                                  * non-existing alert...
858                                  */
859                                 FIX ME
860 #endif
861                                 s->rstate=SSL_ST_READ_HEADER;
862                                 rr->length = 0;
863                                 goto start;
864                                 }
865
866                         /* now move 'n' bytes: */
867                         for ( k = 0; k < dest_maxlen; k++)
868                                 {
869                                 dest[k] = rr->data[rr->off++];
870                                 rr->length--;
871                                 }
872                         *dest_len = dest_maxlen;
873                         }
874                 }
875
876         /* s->d1->handshake_fragment_len == 12  iff  rr->type == SSL3_RT_HANDSHAKE;
877          * s->d1->alert_fragment_len == 7      iff  rr->type == SSL3_RT_ALERT.
878          * (Possibly rr is 'empty' now, i.e. rr->length may be 0.) */
879
880         /* If we are a client, check for an incoming 'Hello Request': */
881         if ((!s->server) &&
882                 (s->d1->handshake_fragment_len >= DTLS1_HM_HEADER_LENGTH) &&
883                 (s->d1->handshake_fragment[0] == SSL3_MT_HELLO_REQUEST) &&
884                 (s->session != NULL) && (s->session->cipher != NULL))
885                 {
886                 s->d1->handshake_fragment_len = 0;
887
888                 if ((s->d1->handshake_fragment[1] != 0) ||
889                         (s->d1->handshake_fragment[2] != 0) ||
890                         (s->d1->handshake_fragment[3] != 0))
891                         {
892                         al=SSL_AD_DECODE_ERROR;
893                         SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_BAD_HELLO_REQUEST);
894                         goto err;
895                         }
896
897                 /* no need to check sequence number on HELLO REQUEST messages */
898
899                 if (s->msg_callback)
900                         s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, 
901                                 s->d1->handshake_fragment, 4, s, s->msg_callback_arg);
902
903                 if (SSL_is_init_finished(s) &&
904                         !(s->s3->flags & SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS) &&
905                         !s->s3->renegotiate)
906                         {
907                         ssl3_renegotiate(s);
908                         if (ssl3_renegotiate_check(s))
909                                 {
910                                 i=s->handshake_func(s);
911                                 if (i < 0) return(i);
912                                 if (i == 0)
913                                         {
914                                         SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_SSL_HANDSHAKE_FAILURE);
915                                         return(-1);
916                                         }
917
918                                 if (!(s->mode & SSL_MODE_AUTO_RETRY))
919                                         {
920                                         if (s->s3->rbuf.left == 0) /* no read-ahead left? */
921                                                 {
922                                                 BIO *bio;
923                                                 /* In the case where we try to read application data,
924                                                  * but we trigger an SSL handshake, we return -1 with
925                                                  * the retry option set.  Otherwise renegotiation may
926                                                  * cause nasty problems in the blocking world */
927                                                 s->rwstate=SSL_READING;
928                                                 bio=SSL_get_rbio(s);
929                                                 BIO_clear_retry_flags(bio);
930                                                 BIO_set_retry_read(bio);
931                                                 return(-1);
932                                                 }
933                                         }
934                                 }
935                         }
936                 /* we either finished a handshake or ignored the request,
937                  * now try again to obtain the (application) data we were asked for */
938                 goto start;
939                 }
940
941         if (s->d1->alert_fragment_len >= DTLS1_AL_HEADER_LENGTH)
942                 {
943                 int alert_level = s->d1->alert_fragment[0];
944                 int alert_descr = s->d1->alert_fragment[1];
945
946                 s->d1->alert_fragment_len = 0;
947
948                 if (s->msg_callback)
949                         s->msg_callback(0, s->version, SSL3_RT_ALERT, 
950                                 s->d1->alert_fragment, 2, s, s->msg_callback_arg);
951
952                 if (s->info_callback != NULL)
953                         cb=s->info_callback;
954                 else if (s->ctx->info_callback != NULL)
955                         cb=s->ctx->info_callback;
956
957                 if (cb != NULL)
958                         {
959                         j = (alert_level << 8) | alert_descr;
960                         cb(s, SSL_CB_READ_ALERT, j);
961                         }
962
963                 if (alert_level == 1) /* warning */
964                         {
965                         s->s3->warn_alert = alert_descr;
966                         if (alert_descr == SSL_AD_CLOSE_NOTIFY)
967                                 {
968                                 s->shutdown |= SSL_RECEIVED_SHUTDOWN;
969                                 return(0);
970                                 }
971 #if 0
972             /* XXX: this is a possible improvement in the future */
973                         /* now check if it's a missing record */
974                         if (alert_descr == DTLS1_AD_MISSING_HANDSHAKE_MESSAGE)
975                                 {
976                                 unsigned short seq;
977                                 unsigned int frag_off;
978                                 unsigned char *p = &(s->d1->alert_fragment[2]);
979
980                                 n2s(p, seq);
981                                 n2l3(p, frag_off);
982
983                                 dtls1_retransmit_message(s, seq, frag_off, &found);
984                                 if ( ! found  && SSL_in_init(s))
985                                         {
986                                         /* fprintf( stderr,"in init = %d\n", SSL_in_init(s)); */
987                                         /* requested a message not yet sent, 
988                                            send an alert ourselves */
989                                         ssl3_send_alert(s,SSL3_AL_WARNING,
990                                                 DTLS1_AD_MISSING_HANDSHAKE_MESSAGE);
991                                         }
992                                 }
993 #endif
994                         }
995                 else if (alert_level == 2) /* fatal */
996                         {
997                         char tmp[16];
998
999                         s->rwstate=SSL_NOTHING;
1000                         s->s3->fatal_alert = alert_descr;
1001                         SSLerr(SSL_F_DTLS1_READ_BYTES, SSL_AD_REASON_OFFSET + alert_descr);
1002                         BIO_snprintf(tmp,sizeof tmp,"%d",alert_descr);
1003                         ERR_add_error_data(2,"SSL alert number ",tmp);
1004                         s->shutdown|=SSL_RECEIVED_SHUTDOWN;
1005                         SSL_CTX_remove_session(s->ctx,s->session);
1006                         return(0);
1007                         }
1008                 else
1009                         {
1010                         al=SSL_AD_ILLEGAL_PARAMETER;
1011                         SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_UNKNOWN_ALERT_TYPE);
1012                         goto f_err;
1013                         }
1014
1015                 goto start;
1016                 }
1017
1018         if (s->shutdown & SSL_SENT_SHUTDOWN) /* but we have not received a shutdown */
1019                 {
1020                 s->rwstate=SSL_NOTHING;
1021                 rr->length=0;
1022                 return(0);
1023                 }
1024
1025         if (rr->type == SSL3_RT_CHANGE_CIPHER_SPEC)
1026                 {
1027                 struct ccs_header_st ccs_hdr;
1028
1029                 dtls1_get_ccs_header(rr->data, &ccs_hdr);
1030
1031                 /* 'Change Cipher Spec' is just a single byte, so we know
1032                  * exactly what the record payload has to look like */
1033                 /* XDTLS: check that epoch is consistent */
1034                 if (    (rr->length != DTLS1_CCS_HEADER_LENGTH) || 
1035                         (rr->off != 0) || (rr->data[0] != SSL3_MT_CCS))
1036                         {
1037                         i=SSL_AD_ILLEGAL_PARAMETER;
1038                         SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_BAD_CHANGE_CIPHER_SPEC);
1039                         goto err;
1040                         }
1041
1042                 rr->length=0;
1043
1044                 if (s->msg_callback)
1045                         s->msg_callback(0, s->version, SSL3_RT_CHANGE_CIPHER_SPEC, 
1046                                 rr->data, 1, s, s->msg_callback_arg);
1047
1048                 s->s3->change_cipher_spec=1;
1049                 if (!ssl3_do_change_cipher_spec(s))
1050                         goto err;
1051
1052                 /* do this whenever CCS is processed */
1053                 dtls1_reset_seq_numbers(s, SSL3_CC_READ);
1054
1055                 goto start;
1056                 }
1057
1058         /* Unexpected handshake message (Client Hello, or protocol violation) */
1059         if ((s->d1->handshake_fragment_len >= DTLS1_HM_HEADER_LENGTH) && 
1060                 !s->in_handshake)
1061                 {
1062                 struct hm_header_st msg_hdr;
1063                 
1064                 /* this may just be a stale retransmit */
1065                 dtls1_get_message_header(rr->data, &msg_hdr);
1066                 if( rr->epoch != s->d1->r_epoch)
1067                         {
1068                         rr->length = 0;
1069                         goto start;
1070                         }
1071
1072                 if (((s->state&SSL_ST_MASK) == SSL_ST_OK) &&
1073                         !(s->s3->flags & SSL3_FLAGS_NO_RENEGOTIATE_CIPHERS))
1074                         {
1075 #if 0 /* worked only because C operator preferences are not as expected (and
1076        * because this is not really needed for clients except for detecting
1077        * protocol violations): */
1078                         s->state=SSL_ST_BEFORE|(s->server)
1079                                 ?SSL_ST_ACCEPT
1080                                 :SSL_ST_CONNECT;
1081 #else
1082                         s->state = s->server ? SSL_ST_ACCEPT : SSL_ST_CONNECT;
1083 #endif
1084                         s->new_session=1;
1085                         }
1086                 i=s->handshake_func(s);
1087                 if (i < 0) return(i);
1088                 if (i == 0)
1089                         {
1090                         SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_SSL_HANDSHAKE_FAILURE);
1091                         return(-1);
1092                         }
1093
1094                 if (!(s->mode & SSL_MODE_AUTO_RETRY))
1095                         {
1096                         if (s->s3->rbuf.left == 0) /* no read-ahead left? */
1097                                 {
1098                                 BIO *bio;
1099                                 /* In the case where we try to read application data,
1100                                  * but we trigger an SSL handshake, we return -1 with
1101                                  * the retry option set.  Otherwise renegotiation may
1102                                  * cause nasty problems in the blocking world */
1103                                 s->rwstate=SSL_READING;
1104                                 bio=SSL_get_rbio(s);
1105                                 BIO_clear_retry_flags(bio);
1106                                 BIO_set_retry_read(bio);
1107                                 return(-1);
1108                                 }
1109                         }
1110                 goto start;
1111                 }
1112
1113         switch (rr->type)
1114                 {
1115         default:
1116 #ifndef OPENSSL_NO_TLS
1117                 /* TLS just ignores unknown message types */
1118                 if (s->version == TLS1_VERSION)
1119                         {
1120                         rr->length = 0;
1121                         goto start;
1122                         }
1123 #endif
1124                 al=SSL_AD_UNEXPECTED_MESSAGE;
1125                 SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_UNEXPECTED_RECORD);
1126                 goto f_err;
1127         case SSL3_RT_CHANGE_CIPHER_SPEC:
1128         case SSL3_RT_ALERT:
1129         case SSL3_RT_HANDSHAKE:
1130                 /* we already handled all of these, with the possible exception
1131                  * of SSL3_RT_HANDSHAKE when s->in_handshake is set, but that
1132                  * should not happen when type != rr->type */
1133                 al=SSL_AD_UNEXPECTED_MESSAGE;
1134                 SSLerr(SSL_F_DTLS1_READ_BYTES,ERR_R_INTERNAL_ERROR);
1135                 goto f_err;
1136         case SSL3_RT_APPLICATION_DATA:
1137                 /* At this point, we were expecting handshake data,
1138                  * but have application data.  If the library was
1139                  * running inside ssl3_read() (i.e. in_read_app_data
1140                  * is set) and it makes sense to read application data
1141                  * at this point (session renegotiation not yet started),
1142                  * we will indulge it.
1143                  */
1144                 if (s->s3->in_read_app_data &&
1145                         (s->s3->total_renegotiations != 0) &&
1146                         ((
1147                                 (s->state & SSL_ST_CONNECT) &&
1148                                 (s->state >= SSL3_ST_CW_CLNT_HELLO_A) &&
1149                                 (s->state <= SSL3_ST_CR_SRVR_HELLO_A)
1150                                 ) || (
1151                                         (s->state & SSL_ST_ACCEPT) &&
1152                                         (s->state <= SSL3_ST_SW_HELLO_REQ_A) &&
1153                                         (s->state >= SSL3_ST_SR_CLNT_HELLO_A)
1154                                         )
1155                                 ))
1156                         {
1157                         s->s3->in_read_app_data=2;
1158                         return(-1);
1159                         }
1160                 else
1161                         {
1162                         al=SSL_AD_UNEXPECTED_MESSAGE;
1163                         SSLerr(SSL_F_DTLS1_READ_BYTES,SSL_R_UNEXPECTED_RECORD);
1164                         goto f_err;
1165                         }
1166                 }
1167         /* not reached */
1168
1169 f_err:
1170         ssl3_send_alert(s,SSL3_AL_FATAL,al);
1171 err:
1172         return(-1);
1173         }
1174
1175 int
1176 dtls1_write_app_data_bytes(SSL *s, int type, const void *buf_, int len)
1177         {
1178         unsigned int n,tot;
1179         int i;
1180
1181         if (SSL_in_init(s) && !s->in_handshake)
1182                 {
1183                 i=s->handshake_func(s);
1184                 if (i < 0) return(i);
1185                 if (i == 0)
1186                         {
1187                         SSLerr(SSL_F_DTLS1_WRITE_APP_DATA_BYTES,SSL_R_SSL_HANDSHAKE_FAILURE);
1188                         return -1;
1189                         }
1190                 }
1191
1192         tot = s->s3->wnum;
1193         n = len - tot;
1194
1195         while( n)
1196                 {
1197                 /* dtls1_write_bytes sends one record at a time, sized according to 
1198                  * the currently known MTU */
1199                 i = dtls1_write_bytes(s, type, buf_, len);
1200                 if (i <= 0) return i;
1201                 
1202                 if ((i == (int)n) ||
1203                         (type == SSL3_RT_APPLICATION_DATA &&
1204                                 (s->mode & SSL_MODE_ENABLE_PARTIAL_WRITE)))
1205                         {
1206                         /* next chunk of data should get another prepended empty fragment
1207                          * in ciphersuites with known-IV weakness: */
1208                         s->s3->empty_fragment_done = 0;
1209                         return tot+i;
1210                         }
1211
1212                 tot += i;
1213                 n-=i;
1214                 }
1215
1216         return tot;
1217         }
1218
1219
1220         /* this only happens when a client hello is received and a handshake 
1221          * is started. */
1222 static int
1223 have_handshake_fragment(SSL *s, int type, unsigned char *buf, 
1224         int len, int peek)
1225         {
1226         
1227         if ((type == SSL3_RT_HANDSHAKE) && (s->d1->handshake_fragment_len > 0))
1228                 /* (partially) satisfy request from storage */
1229                 {
1230                 unsigned char *src = s->d1->handshake_fragment;
1231                 unsigned char *dst = buf;
1232                 unsigned int k,n;
1233                 
1234                 /* peek == 0 */
1235                 n = 0;
1236                 while ((len > 0) && (s->d1->handshake_fragment_len > 0))
1237                         {
1238                         *dst++ = *src++;
1239                         len--; s->d1->handshake_fragment_len--;
1240                         n++;
1241                         }
1242                 /* move any remaining fragment bytes: */
1243                 for (k = 0; k < s->d1->handshake_fragment_len; k++)
1244                         s->d1->handshake_fragment[k] = *src++;
1245                 return n;
1246                 }
1247         
1248         return 0;
1249         }
1250
1251
1252
1253
1254 /* Call this to write data in records of type 'type'
1255  * It will return <= 0 if not all data has been sent or non-blocking IO.
1256  */
1257 int dtls1_write_bytes(SSL *s, int type, const void *buf_, int len)
1258         {
1259         const unsigned char *buf=buf_;
1260         unsigned int tot,n,nw;
1261         int i;
1262         unsigned int mtu;
1263
1264         s->rwstate=SSL_NOTHING;
1265         tot=s->s3->wnum;
1266
1267         n=(len-tot);
1268
1269         /* handshake layer figures out MTU for itself, but data records
1270          * are also sent through this interface, so need to figure out MTU */
1271 #if 0
1272         mtu = BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_GET_MTU, 0, NULL);
1273         mtu += DTLS1_HM_HEADER_LENGTH;  /* HM already inserted */
1274 #endif
1275         mtu = s->d1->mtu;
1276
1277         if (mtu > SSL3_RT_MAX_PLAIN_LENGTH)
1278                 mtu = SSL3_RT_MAX_PLAIN_LENGTH;
1279
1280         if (n > mtu)
1281                 nw=mtu;
1282         else
1283                 nw=n;
1284         
1285         i=do_dtls1_write(s, type, &(buf[tot]), nw, 0);
1286         if (i <= 0)
1287                 {
1288                 s->s3->wnum=tot;
1289                 return i;
1290                 }
1291
1292         if ( (int)s->s3->wnum + i == len)
1293                 s->s3->wnum = 0;
1294         else 
1295                 s->s3->wnum += i;
1296
1297         return tot + i;
1298         }
1299
1300 int do_dtls1_write(SSL *s, int type, const unsigned char *buf, unsigned int len, int create_empty_fragment)
1301         {
1302         unsigned char *p,*pseq;
1303         int i,mac_size,clear=0;
1304         int prefix_len = 0;
1305         SSL3_RECORD *wr;
1306         SSL3_BUFFER *wb;
1307         SSL_SESSION *sess;
1308         int bs;
1309
1310         /* first check if there is a SSL3_BUFFER still being written
1311          * out.  This will happen with non blocking IO */
1312         if (s->s3->wbuf.left != 0)
1313                 {
1314                 OPENSSL_assert(0); /* XDTLS:  want to see if we ever get here */
1315                 return(ssl3_write_pending(s,type,buf,len));
1316                 }
1317
1318         /* If we have an alert to send, lets send it */
1319         if (s->s3->alert_dispatch)
1320                 {
1321                 i=s->method->ssl_dispatch_alert(s);
1322                 if (i <= 0)
1323                         return(i);
1324                 /* if it went, fall through and send more stuff */
1325                 }
1326
1327         if (len == 0 && !create_empty_fragment)
1328                 return 0;
1329
1330         wr= &(s->s3->wrec);
1331         wb= &(s->s3->wbuf);
1332         sess=s->session;
1333
1334         if (    (sess == NULL) ||
1335                 (s->enc_write_ctx == NULL) ||
1336                 (EVP_MD_CTX_md(s->write_hash) == NULL))
1337                 clear=1;
1338
1339         if (clear)
1340                 mac_size=0;
1341         else
1342                 mac_size=EVP_MD_CTX_size(s->write_hash);
1343
1344         /* DTLS implements explicit IV, so no need for empty fragments */
1345 #if 0
1346         /* 'create_empty_fragment' is true only when this function calls itself */
1347         if (!clear && !create_empty_fragment && !s->s3->empty_fragment_done
1348                 && SSL_version(s) != DTLS1_VERSION)
1349                 {
1350                 /* countermeasure against known-IV weakness in CBC ciphersuites
1351                  * (see http://www.openssl.org/~bodo/tls-cbc.txt) 
1352                  */
1353
1354                 if (s->s3->need_empty_fragments && type == SSL3_RT_APPLICATION_DATA)
1355                         {
1356                         /* recursive function call with 'create_empty_fragment' set;
1357                          * this prepares and buffers the data for an empty fragment
1358                          * (these 'prefix_len' bytes are sent out later
1359                          * together with the actual payload) */
1360                         prefix_len = s->method->do_ssl_write(s, type, buf, 0, 1);
1361                         if (prefix_len <= 0)
1362                                 goto err;
1363
1364                         if (s->s3->wbuf.len < (size_t)prefix_len + SSL3_RT_MAX_PACKET_SIZE)
1365                                 {
1366                                 /* insufficient space */
1367                                 SSLerr(SSL_F_DO_DTLS1_WRITE, ERR_R_INTERNAL_ERROR);
1368                                 goto err;
1369                                 }
1370                         }
1371                 
1372                 s->s3->empty_fragment_done = 1;
1373                 }
1374 #endif
1375
1376         p = wb->buf + prefix_len;
1377
1378         /* write the header */
1379
1380         *(p++)=type&0xff;
1381         wr->type=type;
1382
1383         *(p++)=(s->version>>8);
1384         *(p++)=s->version&0xff;
1385
1386         /* field where we are to write out packet epoch, seq num and len */
1387         pseq=p; 
1388         p+=10;
1389
1390         /* lets setup the record stuff. */
1391
1392         /* Make space for the explicit IV in case of CBC.
1393          * (this is a bit of a boundary violation, but what the heck).
1394          */
1395         if ( s->enc_write_ctx && 
1396                 (EVP_CIPHER_mode( s->enc_write_ctx->cipher ) & EVP_CIPH_CBC_MODE))
1397                 bs = EVP_CIPHER_block_size(s->enc_write_ctx->cipher);
1398         else
1399                 bs = 0;
1400
1401         wr->data=p + bs;  /* make room for IV in case of CBC */
1402         wr->length=(int)len;
1403         wr->input=(unsigned char *)buf;
1404
1405         /* we now 'read' from wr->input, wr->length bytes into
1406          * wr->data */
1407
1408         /* first we compress */
1409         if (s->compress != NULL)
1410                 {
1411                 if (!ssl3_do_compress(s))
1412                         {
1413                         SSLerr(SSL_F_DO_DTLS1_WRITE,SSL_R_COMPRESSION_FAILURE);
1414                         goto err;
1415                         }
1416                 }
1417         else
1418                 {
1419                 memcpy(wr->data,wr->input,wr->length);
1420                 wr->input=wr->data;
1421                 }
1422
1423         /* we should still have the output to wr->data and the input
1424          * from wr->input.  Length should be wr->length.
1425          * wr->data still points in the wb->buf */
1426
1427         if (mac_size != 0)
1428                 {
1429                 s->method->ssl3_enc->mac(s,&(p[wr->length + bs]),1);
1430                 wr->length+=mac_size;
1431                 }
1432
1433         /* this is true regardless of mac size */
1434         wr->input=p;
1435         wr->data=p;
1436
1437
1438         /* ssl3_enc can only have an error on read */
1439         if (bs) /* bs != 0 in case of CBC */
1440                 {
1441                 RAND_pseudo_bytes(p,bs);
1442                 /* master IV and last CBC residue stand for
1443                  * the rest of randomness */
1444                 wr->length += bs;
1445                 }
1446
1447         s->method->ssl3_enc->enc(s,1);
1448
1449         /* record length after mac and block padding */
1450 /*      if (type == SSL3_RT_APPLICATION_DATA ||
1451         (type == SSL3_RT_ALERT && ! SSL_in_init(s))) */
1452         
1453         /* there's only one epoch between handshake and app data */
1454         
1455         s2n(s->d1->w_epoch, pseq);
1456
1457         /* XDTLS: ?? */
1458 /*      else
1459         s2n(s->d1->handshake_epoch, pseq); */
1460
1461         memcpy(pseq, &(s->s3->write_sequence[2]), 6);
1462         pseq+=6;
1463         s2n(wr->length,pseq);
1464
1465         /* we should now have
1466          * wr->data pointing to the encrypted data, which is
1467          * wr->length long */
1468         wr->type=type; /* not needed but helps for debugging */
1469         wr->length+=DTLS1_RT_HEADER_LENGTH;
1470
1471 #if 0  /* this is now done at the message layer */
1472         /* buffer the record, making it easy to handle retransmits */
1473         if ( type == SSL3_RT_HANDSHAKE || type == SSL3_RT_CHANGE_CIPHER_SPEC)
1474                 dtls1_buffer_record(s, wr->data, wr->length, 
1475                         *((PQ_64BIT *)&(s->s3->write_sequence[0])));
1476 #endif
1477
1478         ssl3_record_sequence_update(&(s->s3->write_sequence[0]));
1479
1480         if (create_empty_fragment)
1481                 {
1482                 /* we are in a recursive call;
1483                  * just return the length, don't write out anything here
1484                  */
1485                 return wr->length;
1486                 }
1487
1488         /* now let's set up wb */
1489         wb->left = prefix_len + wr->length;
1490         wb->offset = 0;
1491
1492         /* memorize arguments so that ssl3_write_pending can detect bad write retries later */
1493         s->s3->wpend_tot=len;
1494         s->s3->wpend_buf=buf;
1495         s->s3->wpend_type=type;
1496         s->s3->wpend_ret=len;
1497
1498         /* we now just need to write the buffer */
1499         return ssl3_write_pending(s,type,buf,len);
1500 err:
1501         return -1;
1502         }
1503
1504
1505
1506 static int dtls1_record_replay_check(SSL *s, DTLS1_BITMAP *bitmap)
1507         {
1508         int cmp;
1509         unsigned int shift;
1510         const unsigned char *seq = s->s3->read_sequence;
1511
1512         cmp = satsub64be(seq,bitmap->max_seq_num);
1513         if (cmp > 0)
1514                 {
1515                 memcpy (s->s3->rrec.seq_num,seq,8);
1516                 return 1; /* this record in new */
1517                 }
1518         shift = -cmp;
1519         if (shift >= sizeof(bitmap->map)*8)
1520                 return 0; /* stale, outside the window */
1521         else if (bitmap->map & (1UL<<shift))
1522                 return 0; /* record previously received */
1523
1524         memcpy (s->s3->rrec.seq_num,seq,8);
1525         return 1;
1526         }
1527
1528
1529 static void dtls1_record_bitmap_update(SSL *s, DTLS1_BITMAP *bitmap)
1530         {
1531         int cmp;
1532         unsigned int shift;
1533         const unsigned char *seq = s->s3->read_sequence;
1534
1535         cmp = satsub64be(seq,bitmap->max_seq_num);
1536         if (cmp > 0)
1537                 {
1538                 shift = cmp;
1539                 if (shift < sizeof(bitmap->map)*8)
1540                         bitmap->map <<= shift, bitmap->map |= 1UL;
1541                 else
1542                         bitmap->map = 1UL;
1543                 memcpy(bitmap->max_seq_num,seq,8);
1544                 }
1545         else    {
1546                 shift = -cmp;
1547                 if (shift < sizeof(bitmap->map)*8)
1548                         bitmap->map |= 1UL<<shift;
1549                 }
1550         }
1551
1552
1553 int dtls1_dispatch_alert(SSL *s)
1554         {
1555         int i,j;
1556         void (*cb)(const SSL *ssl,int type,int val)=NULL;
1557         unsigned char buf[DTLS1_AL_HEADER_LENGTH];
1558         unsigned char *ptr = &buf[0];
1559
1560         s->s3->alert_dispatch=0;
1561
1562         memset(buf, 0x00, sizeof(buf));
1563         *ptr++ = s->s3->send_alert[0];
1564         *ptr++ = s->s3->send_alert[1];
1565
1566 #ifdef DTLS1_AD_MISSING_HANDSHAKE_MESSAGE
1567         if (s->s3->send_alert[1] == DTLS1_AD_MISSING_HANDSHAKE_MESSAGE)
1568                 {       
1569                 s2n(s->d1->handshake_read_seq, ptr);
1570 #if 0
1571                 if ( s->d1->r_msg_hdr.frag_off == 0)  /* waiting for a new msg */
1572
1573                 else
1574                         s2n(s->d1->r_msg_hdr.seq, ptr); /* partial msg read */
1575 #endif
1576
1577 #if 0
1578                 fprintf(stderr, "s->d1->handshake_read_seq = %d, s->d1->r_msg_hdr.seq = %d\n",s->d1->handshake_read_seq,s->d1->r_msg_hdr.seq);
1579 #endif
1580                 l2n3(s->d1->r_msg_hdr.frag_off, ptr);
1581                 }
1582 #endif
1583
1584         i = do_dtls1_write(s, SSL3_RT_ALERT, &buf[0], sizeof(buf), 0);
1585         if (i <= 0)
1586                 {
1587                 s->s3->alert_dispatch=1;
1588                 /* fprintf( stderr, "not done with alert\n" ); */
1589                 }
1590         else
1591                 {
1592                 if (s->s3->send_alert[0] == SSL3_AL_FATAL
1593 #ifdef DTLS1_AD_MISSING_HANDSHAKE_MESSAGE
1594                     || s->s3->send_alert[1] == DTLS1_AD_MISSING_HANDSHAKE_MESSAGE
1595 #endif
1596                     )
1597                         (void)BIO_flush(s->wbio);
1598
1599                 if (s->msg_callback)
1600                         s->msg_callback(1, s->version, SSL3_RT_ALERT, s->s3->send_alert, 
1601                                 2, s, s->msg_callback_arg);
1602
1603                 if (s->info_callback != NULL)
1604                         cb=s->info_callback;
1605                 else if (s->ctx->info_callback != NULL)
1606                         cb=s->ctx->info_callback;
1607
1608                 if (cb != NULL)
1609                         {
1610                         j=(s->s3->send_alert[0]<<8)|s->s3->send_alert[1];
1611                         cb(s,SSL_CB_WRITE_ALERT,j);
1612                         }
1613                 }
1614         return(i);
1615         }
1616
1617
1618 static DTLS1_BITMAP *
1619 dtls1_get_bitmap(SSL *s, SSL3_RECORD *rr, unsigned int *is_next_epoch)
1620     {
1621     
1622     *is_next_epoch = 0;
1623
1624     /* In current epoch, accept HM, CCS, DATA, & ALERT */
1625     if (rr->epoch == s->d1->r_epoch)
1626         return &s->d1->bitmap;
1627
1628     /* Only HM and ALERT messages can be from the next epoch */
1629     else if (rr->epoch == (unsigned long)(s->d1->r_epoch + 1) &&
1630         (rr->type == SSL3_RT_HANDSHAKE ||
1631             rr->type == SSL3_RT_ALERT))
1632         {
1633         *is_next_epoch = 1;
1634         return &s->d1->next_bitmap;
1635         }
1636
1637     return NULL;
1638     }
1639
1640 #if 0
1641 static int
1642 dtls1_record_needs_buffering(SSL *s, SSL3_RECORD *rr, unsigned short *priority,
1643         unsigned long *offset)
1644         {
1645
1646         /* alerts are passed up immediately */
1647         if ( rr->type == SSL3_RT_APPLICATION_DATA ||
1648                 rr->type == SSL3_RT_ALERT)
1649                 return 0;
1650
1651         /* Only need to buffer if a handshake is underway.
1652          * (this implies that Hello Request and Client Hello are passed up
1653          * immediately) */
1654         if ( SSL_in_init(s))
1655                 {
1656                 unsigned char *data = rr->data;
1657                 /* need to extract the HM/CCS sequence number here */
1658                 if ( rr->type == SSL3_RT_HANDSHAKE ||
1659                         rr->type == SSL3_RT_CHANGE_CIPHER_SPEC)
1660                         {
1661                         unsigned short seq_num;
1662                         struct hm_header_st msg_hdr;
1663                         struct ccs_header_st ccs_hdr;
1664
1665                         if ( rr->type == SSL3_RT_HANDSHAKE)
1666                                 {
1667                                 dtls1_get_message_header(data, &msg_hdr);
1668                                 seq_num = msg_hdr.seq;
1669                                 *offset = msg_hdr.frag_off;
1670                                 }
1671                         else
1672                                 {
1673                                 dtls1_get_ccs_header(data, &ccs_hdr);
1674                                 seq_num = ccs_hdr.seq;
1675                                 *offset = 0;
1676                                 }
1677                                 
1678                         /* this is either a record we're waiting for, or a
1679                          * retransmit of something we happened to previously 
1680                          * receive (higher layers will drop the repeat silently */
1681                         if ( seq_num < s->d1->handshake_read_seq)
1682                                 return 0;
1683                         if (rr->type == SSL3_RT_HANDSHAKE && 
1684                                 seq_num == s->d1->handshake_read_seq &&
1685                                 msg_hdr.frag_off < s->d1->r_msg_hdr.frag_off)
1686                                 return 0;
1687                         else if ( seq_num == s->d1->handshake_read_seq &&
1688                                 (rr->type == SSL3_RT_CHANGE_CIPHER_SPEC ||
1689                                         msg_hdr.frag_off == s->d1->r_msg_hdr.frag_off))
1690                                 return 0;
1691                         else
1692                                 {
1693                                 *priority = seq_num;
1694                                 return 1;
1695                                 }
1696                         }
1697                 else /* unknown record type */
1698                         return 0;
1699                 }
1700
1701         return 0;
1702         }
1703 #endif
1704
1705 void
1706 dtls1_reset_seq_numbers(SSL *s, int rw)
1707         {
1708         unsigned char *seq;
1709         unsigned int seq_bytes = sizeof(s->s3->read_sequence);
1710
1711         if ( rw & SSL3_CC_READ)
1712                 {
1713                 seq = s->s3->read_sequence;
1714                 s->d1->r_epoch++;
1715                 memcpy(&(s->d1->bitmap), &(s->d1->next_bitmap), sizeof(DTLS1_BITMAP));
1716                 memset(&(s->d1->next_bitmap), 0x00, sizeof(DTLS1_BITMAP));
1717                 }
1718         else
1719                 {
1720                 seq = s->s3->write_sequence;
1721                 s->d1->w_epoch++;
1722                 }
1723
1724         memset(seq, 0x00, seq_bytes);
1725         }
1726
1727
1728 static void
1729 dtls1_clear_timeouts(SSL *s)
1730         {
1731         memset(&(s->d1->timeout), 0x00, sizeof(struct dtls1_timeout_st));
1732         }