text: /* ssl/d1_both.c */
  /* 
   * DTLS implementation written by Nagendra Modadugu
   * (nagendra@cs.stanford.edu) for the OpenSSL project 2005.  
   */
  /* ====================================================================
   * Copyright (c) 1998-2005 The OpenSSL Project.  All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   *
   * 1. Redistributions of source code must retain the above copyright
   *    notice, this list of conditions and the following disclaimer. 
   *
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in
   *    the documentation and/or other materials provided with the
   *    distribution.
   *
   * 3. All advertising materials mentioning features or use of this
   *    software must display the following acknowledgment:
   *    "This product includes software developed by the OpenSSL Project
   *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
   *
   * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
   *    endorse or promote products derived from this software without
   *    prior written permission. For written permission, please contact
   *    openssl-core@openssl.org.
   *
   * 5. Products derived from this software may not be called "OpenSSL"
   *    nor may "OpenSSL" appear in their names without prior written
   *    permission of the OpenSSL Project.
   *
   * 6. Redistributions of any form whatsoever must retain the following
   *    acknowledgment:
   *    "This product includes software developed by the OpenSSL Project
   *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
   *
   * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
   * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
   * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
   * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
   * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
   * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
   * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
   * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
   * OF THE POSSIBILITY OF SUCH DAMAGE.
   * ====================================================================
   *
   * This product includes cryptographic software written by Eric Young
   * (eay@cryptsoft.com).  This product includes software written by Tim
   * Hudson (tjh@cryptsoft.com).
   *
   */
  /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
   * All rights reserved.
   *
   * This package is an SSL implementation written
   * by Eric Young (eay@cryptsoft.com).
   * The implementation was written so as to conform with Netscapes SSL.
   * 
   * This library is free for commercial and non-commercial use as long as
   * the following conditions are aheared to.  The following conditions
   * apply to all code found in this distribution, be it the RC4, RSA,
   * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
   * included with this distribution is covered by the same copyright terms
   * except that the holder is Tim Hudson (tjh@cryptsoft.com).
   * 
   * Copyright remains Eric Young's, and as such any Copyright notices in
   * the code are not to be removed.
   * If this package is used in a product, Eric Young should be given attribution
   * as the author of the parts of the library used.
   * This can be in the form of a textual message at program startup or
   * in documentation (online or textual) provided with the package.
   * 
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions
   * are met:
   * 1. Redistributions of source code must retain the copyright
   *    notice, this list of conditions and the following disclaimer.
   * 2. Redistributions in binary form must reproduce the above copyright
   *    notice, this list of conditions and the following disclaimer in the
   *    documentation and/or other materials provided with the distribution.
   * 3. All advertising materials mentioning features or use of this software
   *    must display the following acknowledgement:
   *    "This product includes cryptographic software written by
   *     Eric Young (eay@cryptsoft.com)"
   *    The word 'cryptographic' can be left out if the rouines from the library
   *    being used are not cryptographic related :-).
   * 4. If you include any Windows specific code (or a derivative thereof) from 
   *    the apps directory (application code) you must include an acknowledgement:
   *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
   * 
   * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
   * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   * SUCH DAMAGE.
   * 
   * The licence and distribution terms for any publically available version or
   * derivative of this code cannot be changed.  i.e. this code cannot simply be
   * copied and put under another distribution licence
   * [including the GNU Public Licence.]
   */
  
  #include <limits.h>
  #include <string.h>
  #include <stdio.h>
  #include "ssl_locl.h"
  #include <openssl/buffer.h>
  #include <openssl/rand.h>
  #include <openssl/objects.h>
  #include <openssl/evp.h>
  #include <openssl/x509.h>
  
  #define RSMBLY_BITMASK_SIZE(msg_len) (((msg_len) + 7) / 8)
  
  #define RSMBLY_BITMASK_MARK(bitmask, start, end) { \
  			if ((end) - (start) <= 8) { \
  				long ii; \
  				for (ii = (start); ii < (end); ii++) bitmask[((ii) >> 3)] |= (1 << ((ii) & 7)); \
  			} else { \
  				long ii; \
  				bitmask[((start) >> 3)] |= bitmask_start_values[((start) & 7)]; \
  				for (ii = (((start) >> 3) + 1); ii < ((((end) - 1)) >> 3); ii++) bitmask[ii] = 0xff; \
  				bitmask[(((end) - 1) >> 3)] |= bitmask_end_values[((end) & 7)]; \
  			} }
  
  #define RSMBLY_BITMASK_IS_COMPLETE(bitmask, msg_len, is_complete) { \
  			long ii; \
  			OPENSSL_assert((msg_len) > 0); \
  			is_complete = 1; \
  			if (bitmask[(((msg_len) - 1) >> 3)] != bitmask_end_values[((msg_len) & 7)]) is_complete = 0; \
  			if (is_complete) for (ii = (((msg_len) - 1) >> 3) - 1; ii >= 0 ; ii--) \
  				if (bitmask[ii] != 0xff) { is_complete = 0; break; } }
  
  #if 0
  #define RSMBLY_BITMASK_PRINT(bitmask, msg_len) { \
  			long ii; \
  			printf("bitmask: "); for (ii = 0; ii < (msg_len); ii++) \
  			printf("%d ", (bitmask[ii >> 3] & (1 << (ii & 7))) >> (ii & 7)); \
  			printf("\n"); }
  #endif
  
  static unsigned char bitmask_start_values[] = {0xff, 0xfe, 0xfc, 0xf8, 0xf0, 0xe0, 0xc0, 0x80};
  static unsigned char bitmask_end_values[]   = {0xff, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f};
  
  /* XDTLS:  figure out the right values */
  static unsigned int g_probable_mtu[] = {1500 - 28, 512 - 28, 256 - 28};
  
  static unsigned int dtls1_guess_mtu(unsigned int curr_mtu);
  static void dtls1_fix_message_header(SSL *s, unsigned long frag_off, 
  	unsigned long frag_len);
  static unsigned char *dtls1_write_message_header(SSL *s,
  	unsigned char *p);
  static 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);
  static long dtls1_get_message_fragment(SSL *s, int st1, int stn, 
  	long max, int *ok);
  
  static hm_fragment *
  dtls1_hm_fragment_new(unsigned long frag_len, int reassembly)
  	{
  	hm_fragment *frag = NULL;
  	unsigned char *buf = NULL;
  	unsigned char *bitmask = NULL;
  
  	frag = (hm_fragment *)OPENSSL_malloc(sizeof(hm_fragment));
  	if ( frag == NULL)
  		return NULL;
  
  	if (frag_len)
  		{
  		buf = (unsigned char *)OPENSSL_malloc(frag_len);
  		if ( buf == NULL)
  			{
  			OPENSSL_free(frag);
  			return NULL;
  			}
  		}
  
  	/* zero length fragment gets zero frag->fragment */
  	frag->fragment = buf;
  
  	/* Initialize reassembly bitmask if necessary */
  	if (reassembly)
  		{
  		bitmask = (unsigned char *)OPENSSL_malloc(RSMBLY_BITMASK_SIZE(frag_len));
  		if (bitmask == NULL)
  			{
  			if (buf != NULL) OPENSSL_free(buf);
  			OPENSSL_free(frag);
  			return NULL;
  			}
  		memset(bitmask, 0, RSMBLY_BITMASK_SIZE(frag_len));
  		}
  
  	frag->reassembly = bitmask;
  
  	return frag;
  	}
  
  static void
  dtls1_hm_fragment_free(hm_fragment *frag)
  	{
  	if (frag->fragment) OPENSSL_free(frag->fragment);
  	if (frag->reassembly) OPENSSL_free(frag->reassembly);
  	OPENSSL_free(frag);
  	}
  
  /* send s->init_buf in records of type 'type' (SSL3_RT_HANDSHAKE or SSL3_RT_CHANGE_CIPHER_SPEC) */
  int dtls1_do_write(SSL *s, int type)
  	{
  	int ret;
  	int curr_mtu;
  	unsigned int len, frag_off, mac_size, blocksize;
  
  	/* AHA!  Figure out the MTU, and stick to the right size */
  	if (s->d1->mtu < dtls1_min_mtu() && !(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU))
  		{
  		s->d1->mtu = 
  			BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
  
  		/* I've seen the kernel return bogus numbers when it doesn't know
  		 * (initial write), so just make sure we have a reasonable number */
  		if (s->d1->mtu < dtls1_min_mtu())
  			{
  			s->d1->mtu = 0;
  			s->d1->mtu = dtls1_guess_mtu(s->d1->mtu);
  			BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SET_MTU, 
  				s->d1->mtu, NULL);
  			}
  		}
  #if 0 
  	mtu = s->d1->mtu;
  
  	fprintf(stderr, "using MTU = %d\n", mtu);
  
  	mtu -= (DTLS1_HM_HEADER_LENGTH + DTLS1_RT_HEADER_LENGTH);
  
  	curr_mtu = mtu - BIO_wpending(SSL_get_wbio(s));
  
  	if ( curr_mtu > 0)
  		mtu = curr_mtu;
  	else if ( ( ret = BIO_flush(SSL_get_wbio(s))) <= 0)
  		return ret;
  
  	if ( BIO_wpending(SSL_get_wbio(s)) + s->init_num >= mtu)
  		{
  		ret = BIO_flush(SSL_get_wbio(s));
  		if ( ret <= 0)
  			return ret;
  		mtu = s->d1->mtu - (DTLS1_HM_HEADER_LENGTH + DTLS1_RT_HEADER_LENGTH);
  		}
  #endif
  
  	OPENSSL_assert(s->d1->mtu >= dtls1_min_mtu());  /* should have something reasonable now */
  
  	if ( s->init_off == 0  && type == SSL3_RT_HANDSHAKE)
  		OPENSSL_assert(s->init_num == 
  			(int)s->d1->w_msg_hdr.msg_len + DTLS1_HM_HEADER_LENGTH);
  
  	if (s->write_hash)
  		mac_size = EVP_MD_size(s->write_hash);
  	else
  		mac_size = 0;
  
  	if (s->enc_write_ctx && 
  		(EVP_CIPHER_mode( s->enc_write_ctx->cipher) & EVP_CIPH_CBC_MODE))
  		blocksize = 2 * EVP_CIPHER_block_size(s->enc_write_ctx->cipher);
  	else
  		blocksize = 0;
  
  	frag_off = 0;
  	while( s->init_num)
  		{
  		curr_mtu = s->d1->mtu - BIO_wpending(SSL_get_wbio(s)) - 
  			DTLS1_RT_HEADER_LENGTH - mac_size - blocksize;
  
  		if ( curr_mtu <= DTLS1_HM_HEADER_LENGTH)
  			{
  			/* grr.. we could get an error if MTU picked was wrong */
  			ret = BIO_flush(SSL_get_wbio(s));
  			if ( ret <= 0)
  				return ret;
  			curr_mtu = s->d1->mtu - DTLS1_RT_HEADER_LENGTH -
  				mac_size - blocksize;
  			}
  
  		if ( s->init_num > curr_mtu)
  			len = curr_mtu;
  		else
  			len = s->init_num;
  
  
  		/* XDTLS: this function is too long.  split out the CCS part */
  		if ( type == SSL3_RT_HANDSHAKE)
  			{
  			if ( s->init_off != 0)
  				{
  				OPENSSL_assert(s->init_off > DTLS1_HM_HEADER_LENGTH);
  				s->init_off -= DTLS1_HM_HEADER_LENGTH;
  				s->init_num += DTLS1_HM_HEADER_LENGTH;
  
  				/* write atleast DTLS1_HM_HEADER_LENGTH bytes */
  				if ( len <= DTLS1_HM_HEADER_LENGTH)  
  					len += DTLS1_HM_HEADER_LENGTH;
  				}
  
  			dtls1_fix_message_header(s, frag_off, 
  				len - DTLS1_HM_HEADER_LENGTH);
  
  			dtls1_write_message_header(s, (unsigned char *)&s->init_buf->data[s->init_off]);
  
  			OPENSSL_assert(len >= DTLS1_HM_HEADER_LENGTH);
  			}
  
  		ret=dtls1_write_bytes(s,type,&s->init_buf->data[s->init_off],
  			len);
  		if (ret < 0)
  			{
  			/* might need to update MTU here, but we don't know
  			 * which previous packet caused the failure -- so can't
  			 * really retransmit anything.  continue as if everything
  			 * is fine and wait for an alert to handle the
  			 * retransmit 
  			 */
  			if ( BIO_ctrl(SSL_get_wbio(s),
  				BIO_CTRL_DGRAM_MTU_EXCEEDED, 0, NULL) > 0 )
  				s->d1->mtu = BIO_ctrl(SSL_get_wbio(s),
  					BIO_CTRL_DGRAM_QUERY_MTU, 0, NULL);
  			else
  				return(-1);
  			}
  		else
  			{
  
  			/* bad if this assert fails, only part of the handshake
  			 * message got sent.  but why would this happen? */
  			OPENSSL_assert(len == (unsigned int)ret);
  
  			if (type == SSL3_RT_HANDSHAKE && ! s->d1->retransmitting)
  				{
  				/* should not be done for 'Hello Request's, but in that case
  				 * we'll ignore the result anyway */
  				unsigned char *p = (unsigned char *)&s->init_buf->data[s->init_off];
  				const struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
  				int xlen;
  
  				if (frag_off == 0 && s->client_version != DTLS1_BAD_VER)
  					{
  					/* reconstruct message header is if it
  					 * is being sent in single fragment */
  					*p++ = msg_hdr->type;
  					l2n3(msg_hdr->msg_len,p);
  					s2n (msg_hdr->seq,p);
  					l2n3(0,p);
  					l2n3(msg_hdr->msg_len,p);
  					p  -= DTLS1_HM_HEADER_LENGTH;
  					xlen = ret;
  					}
  				else
  					{
  					p  += DTLS1_HM_HEADER_LENGTH;
  					xlen = ret - DTLS1_HM_HEADER_LENGTH;
  					}
  
  				ssl3_finish_mac(s, p, xlen);
  				}
  
  			if (ret == s->init_num)
  				{
  				if (s->msg_callback)
  					s->msg_callback(1, s->version, type, s->init_buf->data, 
  						(size_t)(s->init_off + s->init_num), s, 
  						s->msg_callback_arg);
  
  				s->init_off = 0;  /* done writing this message */
  				s->init_num = 0;
  
  				return(1);
  				}
  			s->init_off+=ret;
  			s->init_num-=ret;
  			frag_off += (ret -= DTLS1_HM_HEADER_LENGTH);
  			}
  		}
  	return(0);
  	}
  
  
  /* Obtain handshake message of message type 'mt' (any if mt == -1),
   * maximum acceptable body length 'max'.
   * Read an entire handshake message.  Handshake messages arrive in
   * fragments.
   */
  long dtls1_get_message(SSL *s, int st1, int stn, int mt, long max, int *ok)
  	{
  	int i, al;
  	struct hm_header_st *msg_hdr;
  	unsigned char *p;
  	unsigned long msg_len;
  
  	/* s3->tmp is used to store messages that are unexpected, caused
  	 * by the absence of an optional handshake message */
  	if (s->s3->tmp.reuse_message)
  		{
  		s->s3->tmp.reuse_message=0;
  		if ((mt >= 0) && (s->s3->tmp.message_type != mt))
  			{
  			al=SSL_AD_UNEXPECTED_MESSAGE;
  			SSLerr(SSL_F_DTLS1_GET_MESSAGE,SSL_R_UNEXPECTED_MESSAGE);
  			goto f_err;
  			}
  		*ok=1;
  		s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
  		s->init_num = (int)s->s3->tmp.message_size;
  		return s->init_num;
  		}
  
  	msg_hdr = &s->d1->r_msg_hdr;
  	memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
  
  again:
  	i = dtls1_get_message_fragment(s, st1, stn, max, ok);
  	if ( i == DTLS1_HM_BAD_FRAGMENT ||
  		i == DTLS1_HM_FRAGMENT_RETRY)  /* bad fragment received */
  		goto again;
  	else if ( i <= 0 && !*ok)
  		return i;
  
  	p = (unsigned char *)s->init_buf->data;
  	msg_len = msg_hdr->msg_len;
  
  	/* reconstruct message header */
  	*(p++) = msg_hdr->type;
  	l2n3(msg_len,p);
  	s2n (msg_hdr->seq,p);
  	l2n3(0,p);
  	l2n3(msg_len,p);
  	if (s->version != DTLS1_BAD_VER) {
  		p       -= DTLS1_HM_HEADER_LENGTH;
  		msg_len += DTLS1_HM_HEADER_LENGTH;
  	}
  
  	ssl3_finish_mac(s, p, msg_len);
  	if (s->msg_callback)
  		s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE,
  			p, msg_len,
  			s, s->msg_callback_arg);
  
  	memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
  
  	/* Don't change sequence numbers while listening */
  	if (!s->d1->listen)
  		s->d1->handshake_read_seq++;
  
  	s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
  	return s->init_num;
  
  f_err:
  	ssl3_send_alert(s,SSL3_AL_FATAL,al);
  	*ok = 0;
  	return -1;
  	}
  
  
  static int dtls1_preprocess_fragment(SSL *s,struct hm_header_st *msg_hdr,int max)
  	{
  	size_t frag_off,frag_len,msg_len;
  
  	msg_len  = msg_hdr->msg_len;
  	frag_off = msg_hdr->frag_off;
  	frag_len = msg_hdr->frag_len;
  
  	/* sanity checking */
  	if ( (frag_off+frag_len) > msg_len)
  		{
  		SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
  		return SSL_AD_ILLEGAL_PARAMETER;
  		}
  
  	if ( (frag_off+frag_len) > (unsigned long)max)
  		{
  		SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
  		return SSL_AD_ILLEGAL_PARAMETER;
  		}
  
  	if ( s->d1->r_msg_hdr.frag_off == 0) /* first fragment */
  		{
  		/* msg_len is limited to 2^24, but is effectively checked
  		 * against max above */
  		if (!BUF_MEM_grow_clean(s->init_buf,(int)msg_len+DTLS1_HM_HEADER_LENGTH))
  			{
  			SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,ERR_R_BUF_LIB);
  			return SSL_AD_INTERNAL_ERROR;
  			}
  
  		s->s3->tmp.message_size  = msg_len;
  		s->d1->r_msg_hdr.msg_len = msg_len;
  		s->s3->tmp.message_type  = msg_hdr->type;
  		s->d1->r_msg_hdr.type    = msg_hdr->type;
  		s->d1->r_msg_hdr.seq     = msg_hdr->seq;
  		}
  	else if (msg_len != s->d1->r_msg_hdr.msg_len)
  		{
  		/* They must be playing with us! BTW, failure to enforce
  		 * upper limit would open possibility for buffer overrun. */
  		SSLerr(SSL_F_DTLS1_PREPROCESS_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
  		return SSL_AD_ILLEGAL_PARAMETER;
  		}
  
  	return 0; /* no error */
  	}
  
  
  static int
  dtls1_retrieve_buffered_fragment(SSL *s, long max, int *ok)
  	{
  	/* (0) check whether the desired fragment is available
  	 * if so:
  	 * (1) copy over the fragment to s->init_buf->data[]
  	 * (2) update s->init_num
  	 */
  	pitem *item;
  	hm_fragment *frag;
  	int al;
  
  	*ok = 0;
  	item = pqueue_peek(s->d1->buffered_messages);
  	if ( item == NULL)
  		return 0;
  
  	frag = (hm_fragment *)item->data;
  	
  	/* Don't return if reassembly still in progress */
  	if (frag->reassembly != NULL)
  		return 0;
  
  	if ( s->d1->handshake_read_seq == frag->msg_header.seq)
  		{
  		unsigned long frag_len = frag->msg_header.frag_len;
  		pqueue_pop(s->d1->buffered_messages);
  
  		al=dtls1_preprocess_fragment(s,&frag->msg_header,max);
  
  		if (al==0) /* no alert */
  			{
  			unsigned char *p = (unsigned char *)s->init_buf->data+DTLS1_HM_HEADER_LENGTH;
  			memcpy(&p[frag->msg_header.frag_off],
  				frag->fragment,frag->msg_header.frag_len);
  			}
  
  		dtls1_hm_fragment_free(frag);
  		pitem_free(item);
  
  		if (al==0)
  			{
  			*ok = 1;
  			return frag_len;
  			}
  
  		ssl3_send_alert(s,SSL3_AL_FATAL,al);
  		s->init_num = 0;
  		*ok = 0;
  		return -1;
  		}
  	else
  		return 0;
  	}
  
  
  static int
  dtls1_reassemble_fragment(SSL *s, struct hm_header_st* msg_hdr, int *ok)
  	{
  	hm_fragment *frag = NULL;
  	pitem *item = NULL;
  	int i = -1, is_complete;
  	PQ_64BIT seq64;
  	unsigned long frag_len = msg_hdr->frag_len, max_len;
  
  	if ((msg_hdr->frag_off+frag_len) > msg_hdr->msg_len)
  		goto err;
  
  	/* Determine maximum allowed message size. Depends on (user set)
  	 * maximum certificate length, but 16k is minimum.
  	 */
  	if (DTLS1_HM_HEADER_LENGTH + SSL3_RT_MAX_ENCRYPTED_LENGTH < s->max_cert_list)
  		max_len = s->max_cert_list;
  	else
  		max_len = DTLS1_HM_HEADER_LENGTH + SSL3_RT_MAX_ENCRYPTED_LENGTH;
  
  	if ((msg_hdr->frag_off+frag_len) > max_len)
  		goto err;
  
  	/* Try to find item in queue */
  	pq_64bit_init(&seq64);
  	pq_64bit_assign_word(&seq64, msg_hdr->seq);
  	item = pqueue_find(s->d1->buffered_messages, seq64);
  	pq_64bit_free(&seq64);
  
  	if (item == NULL)
  		{
  		frag = dtls1_hm_fragment_new(msg_hdr->msg_len, 1);
  		if ( frag == NULL)
  			goto err;
  		memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
  		frag->msg_header.frag_len = frag->msg_header.msg_len;
  		frag->msg_header.frag_off = 0;
  		}
  	else
  		frag = (hm_fragment*) item->data;
  
  	/* If message is already reassembled, this must be a
  	 * retransmit and can be dropped.
  	 */
  	if (frag->reassembly == NULL)
  		{
  		unsigned char devnull [256];
  
  		while (frag_len)
  			{
  			i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
  				devnull,
  				frag_len>sizeof(devnull)?sizeof(devnull):frag_len,0);
  			if (i<=0) goto err;
  			frag_len -= i;
  			}
  		return DTLS1_HM_FRAGMENT_RETRY;
  		}
  
  	/* read the body of the fragment (header has already been read */
  	i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
  		frag->fragment + msg_hdr->frag_off,frag_len,0);
  	if (i<=0 || (unsigned long)i!=frag_len)
  		goto err;
  
  	RSMBLY_BITMASK_MARK(frag->reassembly, (long)msg_hdr->frag_off,
  	                    (long)(msg_hdr->frag_off + frag_len));
  
  	RSMBLY_BITMASK_IS_COMPLETE(frag->reassembly, (long)msg_hdr->msg_len,
  	                           is_complete);
  
  	if (is_complete)
  		{
  		OPENSSL_free(frag->reassembly);
  		frag->reassembly = NULL;
  		}
  
  	if (item == NULL)
  		{
  		pq_64bit_init(&seq64);
  		pq_64bit_assign_word(&seq64, msg_hdr->seq);
  		item = pitem_new(seq64, frag);
  		pq_64bit_free(&seq64);
  
  		if (item == NULL)
  			{
  			goto err;
  			i = -1;
  			}
  
  		pqueue_insert(s->d1->buffered_messages, item);
  		}
  
  	return DTLS1_HM_FRAGMENT_RETRY;
  
  err:
  	if (frag != NULL) dtls1_hm_fragment_free(frag);
  	if (item != NULL) OPENSSL_free(item);
  	*ok = 0;
  	return i;
  	}
  
  
  static int
  dtls1_process_out_of_seq_message(SSL *s, struct hm_header_st* msg_hdr, int *ok)
  {
  	int i=-1;
  	hm_fragment *frag = NULL;
  	pitem *item = NULL;
  	PQ_64BIT seq64;
  	unsigned long frag_len = msg_hdr->frag_len;
  
  	if ((msg_hdr->frag_off+frag_len) > msg_hdr->msg_len)
  		goto err;
  
  	/* Try to find item in queue, to prevent duplicate entries */
  	pq_64bit_init(&seq64);
  	pq_64bit_assign_word(&seq64, msg_hdr->seq);
  	item = pqueue_find(s->d1->buffered_messages, seq64);
  	pq_64bit_free(&seq64);
  
  	/* If we already have an entry and this one is a fragment,
  	 * don't discard it and rather try to reassemble it.
  	 */
  	if (item != NULL && frag_len < msg_hdr->msg_len)
  		item = NULL;
  
  	/* Discard the message if sequence number was already there, is
  	 * too far in the future, already in the queue or if we received
  	 * a FINISHED before the SERVER_HELLO, which then must be a stale
  	 * retransmit.
  	 */
  	if (msg_hdr->seq <= s->d1->handshake_read_seq ||
  		msg_hdr->seq > s->d1->handshake_read_seq + 10 || item != NULL ||
  		(s->d1->handshake_read_seq == 0 && msg_hdr->type == SSL3_MT_FINISHED))
  		{
  		unsigned char devnull [256];
  
  		while (frag_len)
  			{
  			i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
  				devnull,
  				frag_len>sizeof(devnull)?sizeof(devnull):frag_len,0);
  			if (i<=0) goto err;
  			frag_len -= i;
  			}
  		}
  	else
  		{
  		if (frag_len && frag_len < msg_hdr->msg_len)
  			return dtls1_reassemble_fragment(s, msg_hdr, ok);
  
  		frag = dtls1_hm_fragment_new(frag_len, 0);
  		if ( frag == NULL)
  			goto err;
  
  		memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
  
  		if (frag_len)
  			{
  			/* read the body of the fragment (header has already been read) */
  			i = s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
  				frag->fragment,frag_len,0);
  			if (i<=0 || (unsigned long)i!=frag_len)
  				goto err;
  			}
  
  		pq_64bit_init(&seq64);
  		pq_64bit_assign_word(&seq64, msg_hdr->seq);
  
  		item = pitem_new(seq64, frag);
  		pq_64bit_free(&seq64);
  		if ( item == NULL)
  			goto err;
  
  		pqueue_insert(s->d1->buffered_messages, item);
  		}
  
  	return DTLS1_HM_FRAGMENT_RETRY;
  
  err:
  	if ( frag != NULL) dtls1_hm_fragment_free(frag);
  	if ( item != NULL) OPENSSL_free(item);
  	*ok = 0;
  	return i;
  	}
  
  
  static long
  dtls1_get_message_fragment(SSL *s, int st1, int stn, long max, int *ok)
  	{
  	unsigned char wire[DTLS1_HM_HEADER_LENGTH];
  	unsigned long len, frag_off, frag_len;
  	int i,al;
  	struct hm_header_st msg_hdr;
  
  	/* see if we have the required fragment already */
  	if ((frag_len = dtls1_retrieve_buffered_fragment(s,max,ok)) || *ok)
  		{
  		if (*ok)	s->init_num = frag_len;
  		return frag_len;
  		}
  
  	/* read handshake message header */
  	i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,wire,
  		DTLS1_HM_HEADER_LENGTH, 0);
  	if (i <= 0) 	/* nbio, or an error */
  		{
  		s->rwstate=SSL_READING;
  		*ok = 0;
  		return i;
  		}
  	/* Handshake fails if message header is incomplete */
  	if (i != DTLS1_HM_HEADER_LENGTH)
  		{
  		al=SSL_AD_UNEXPECTED_MESSAGE;
  		SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL_R_UNEXPECTED_MESSAGE);
  		goto f_err;
  		}
  
  	/* parse the message fragment header */
  	dtls1_get_message_header(wire, &msg_hdr);
  
  	/* 
  	 * if this is a future (or stale) message it gets buffered
  	 * (or dropped)--no further processing at this time
  	 * While listening, we accept seq 1 (ClientHello with cookie)
  	 * although we're still expecting seq 0 (ClientHello)
  	 */
  	if (msg_hdr.seq != s->d1->handshake_read_seq && !(s->d1->listen && msg_hdr.seq == 1))
  		return dtls1_process_out_of_seq_message(s, &msg_hdr, ok);
  
  	len = msg_hdr.msg_len;
  	frag_off = msg_hdr.frag_off;
  	frag_len = msg_hdr.frag_len;
  
  	if (frag_len && frag_len < len)
  		return dtls1_reassemble_fragment(s, &msg_hdr, ok);
  
  	if (!s->server && s->d1->r_msg_hdr.frag_off == 0 &&
  		wire[0] == SSL3_MT_HELLO_REQUEST)
  		{
  		/* The server may always send 'Hello Request' messages --
  		 * we are doing a handshake anyway now, so ignore them
  		 * if their format is correct. Does not count for
  		 * 'Finished' MAC. */
  		if (wire[1] == 0 && wire[2] == 0 && wire[3] == 0)
  			{
  			if (s->msg_callback)
  				s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, 
  					wire, DTLS1_HM_HEADER_LENGTH, s, 
  					s->msg_callback_arg);
  			
  			s->init_num = 0;
  			return dtls1_get_message_fragment(s, st1, stn,
  				max, ok);
  			}
  		else /* Incorrectly formated Hello request */
  			{
  			al=SSL_AD_UNEXPECTED_MESSAGE;
  			SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL_R_UNEXPECTED_MESSAGE);
  			goto f_err;
  			}
  		}
  
  	if ((al=dtls1_preprocess_fragment(s,&msg_hdr,max)))
  		goto f_err;
  
  	/* XDTLS:  ressurect this when restart is in place */
  	s->state=stn;
  
  	if ( frag_len > 0)
  		{
  		unsigned char *p=(unsigned char *)s->init_buf->data+DTLS1_HM_HEADER_LENGTH;
  
  		i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
  			&p[frag_off],frag_len,0);
  		/* XDTLS:  fix this--message fragments cannot span multiple packets */
  		if (i <= 0)
  			{
  			s->rwstate=SSL_READING;
  			*ok = 0;
  			return i;
  			}
  		}
  	else
  		i = 0;
  
  	/* XDTLS:  an incorrectly formatted fragment should cause the 
  	 * handshake to fail */
  	if (i != (int)frag_len)
  		{
  		al=SSL3_AD_ILLEGAL_PARAMETER;
  		SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL3_AD_ILLEGAL_PARAMETER);
  		goto f_err;
  		}
  
  	*ok = 1;
  
  	/* Note that s->init_num is *not* used as current offset in
  	 * s->init_buf->data, but as a counter summing up fragments'
  	 * lengths: as soon as they sum up to handshake packet
  	 * length, we assume we have got all the fragments. */
  	s->init_num = frag_len;
  	return frag_len;
  
  f_err:
  	ssl3_send_alert(s,SSL3_AL_FATAL,al);
  	s->init_num = 0;
  
  	*ok=0;
  	return(-1);
  	}
  
  int dtls1_send_finished(SSL *s, int a, int b, const char *sender, int slen)
  	{
  	unsigned char *p,*d;
  	int i;
  	unsigned long l;
  
  	if (s->state == a)
  		{
  		d=(unsigned char *)s->init_buf->data;
  		p= &(d[DTLS1_HM_HEADER_LENGTH]);
  
  		i=s->method->ssl3_enc->final_finish_mac(s,
  			&(s->s3->finish_dgst1),
  			&(s->s3->finish_dgst2),
  			sender,slen,s->s3->tmp.finish_md);
  		s->s3->tmp.finish_md_len = i;
  		memcpy(p, s->s3->tmp.finish_md, i);
  		p+=i;
  		l=i;
  
  	/* Copy the finished so we can use it for
  	 * renegotiation checks
  	 */
  	if(s->type == SSL_ST_CONNECT)
  		{
  		OPENSSL_assert(i <= EVP_MAX_MD_SIZE);
  		memcpy(s->s3->previous_client_finished, 
  		       s->s3->tmp.finish_md, i);
  		s->s3->previous_client_finished_len=i;
  		}
  	else
  		{
  		OPENSSL_assert(i <= EVP_MAX_MD_SIZE);
  		memcpy(s->s3->previous_server_finished, 
  		       s->s3->tmp.finish_md, i);
  		s->s3->previous_server_finished_len=i;
  		}
  
  #ifdef OPENSSL_SYS_WIN16
  		/* MSVC 1.5 does not clear the top bytes of the word unless
  		 * I do this.
  		 */
  		l&=0xffff;
  #endif
  
  		d = dtls1_set_message_header(s, d, SSL3_MT_FINISHED, l, 0, l);
  		s->init_num=(int)l+DTLS1_HM_HEADER_LENGTH;
  		s->init_off=0;
  
  		/* buffer the message to handle re-xmits */
  		dtls1_buffer_message(s, 0);
  
  		s->state=b;
  		}
  
  	/* SSL3_ST_SEND_xxxxxx_HELLO_B */
  	return(dtls1_do_write(s,SSL3_RT_HANDSHAKE));
  	}
  
  /* for these 2 messages, we need to
   * ssl->enc_read_ctx			re-init
   * ssl->s3->read_sequence		zero
   * ssl->s3->read_mac_secret		re-init
   * ssl->session->read_sym_enc		assign
   * ssl->session->read_compression	assign
   * ssl->session->read_hash		assign
   */
  int dtls1_send_change_cipher_spec(SSL *s, int a, int b)
  	{ 
  	unsigned char *p;
  
  	if (s->state == a)
  		{
  		p=(unsigned char *)s->init_buf->data;
  		*p++=SSL3_MT_CCS;
  		s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
  		s->init_num=DTLS1_CCS_HEADER_LENGTH;
  
  		if (s->client_version == DTLS1_BAD_VER)
  			{
  			s->d1->next_handshake_write_seq++;
  			s2n(s->d1->handshake_write_seq,p);
  			s->init_num+=2;
  			}
  
  		s->init_off=0;
  
  		dtls1_set_message_header_int(s, SSL3_MT_CCS, 0, 
  			s->d1->handshake_write_seq, 0, 0);
  
  		/* buffer the message to handle re-xmits */
  		dtls1_buffer_message(s, 1);
  
  		s->state=b;
  		}
  
  	/* SSL3_ST_CW_CHANGE_B */
  	return(dtls1_do_write(s,SSL3_RT_CHANGE_CIPHER_SPEC));
  	}
  
  static int dtls1_add_cert_to_buf(BUF_MEM *buf, unsigned long *l, X509 *x)
  	{
  		int n;
  		unsigned char *p;
  
  		n=i2d_X509(x,NULL);
  		if (!BUF_MEM_grow_clean(buf,(int)(n+(*l)+3)))
  			{
  			SSLerr(SSL_F_DTLS1_ADD_CERT_TO_BUF,ERR_R_BUF_LIB);
  			return 0;
  			}
  		p=(unsigned char *)&(buf->data[*l]);
  		l2n3(n,p);
  		i2d_X509(x,&p);
  		*l+=n+3;
  
  		return 1;
  	}
  unsigned long dtls1_output_cert_chain(SSL *s, X509 *x)
  	{
  	unsigned char *p;
  	int i;
  	unsigned long l= 3 + DTLS1_HM_HEADER_LENGTH;
  	BUF_MEM *buf;
  
  	/* TLSv1 sends a chain with nothing in it, instead of an alert */
  	buf=s->init_buf;
  	if (!BUF_MEM_grow_clean(buf,10))
  		{
  		SSLerr(SSL_F_DTLS1_OUTPUT_CERT_CHAIN,ERR_R_BUF_LIB);
  		return(0);
  		}
  	if (x != NULL)
  		{
  		X509_STORE_CTX xs_ctx;
    
  		if (!X509_STORE_CTX_init(&xs_ctx,s->ctx->cert_store,x,NULL))
    			{
    			SSLerr(SSL_F_DTLS1_OUTPUT_CERT_CHAIN,ERR_R_X509_LIB);
    			return(0);
    			}
    
  		X509_verify_cert(&xs_ctx);
  		/* Don't leave errors in the queue */
  		ERR_clear_error();
  		for (i=0; i < sk_X509_num(xs_ctx.chain); i++)
    			{
  			x = sk_X509_value(xs_ctx.chain, i);
  
  			if (!dtls1_add_cert_to_buf(buf, &l, x))
    				{
  				X509_STORE_CTX_cleanup(&xs_ctx);
  				return 0;
    				}
    			}
    		X509_STORE_CTX_cleanup(&xs_ctx);
    		}
  	/* Thawte special :-) */
  	for (i=0; i<sk_X509_num(s->ctx->extra_certs); i++)
  		{
  		x=sk_X509_value(s->ctx->extra_certs,i);
  		if (!dtls1_add_cert_to_buf(buf, &l, x))
  			return 0;
  		}
  
  	l-= (3 + DTLS1_HM_HEADER_LENGTH);
  
  	p=(unsigned char *)&(buf->data[DTLS1_HM_HEADER_LENGTH]);
  	l2n3(l,p);
  	l+=3;
  	p=(unsigned char *)&(buf->data[0]);
  	p = dtls1_set_message_header(s, p, SSL3_MT_CERTIFICATE, l, 0, l);
  
  	l+=DTLS1_HM_HEADER_LENGTH;
  	return(l);
  	}
  
  int dtls1_read_failed(SSL *s, int code)
  	{
  	if ( code > 0)
  		{
  		fprintf( stderr, "invalid state reached %s:%d", __FILE__, __LINE__);
  		return 1;
  		}
  
  	if (!dtls1_is_timer_expired(s))
  		{
  		/* not a timeout, none of our business, 
  		   let higher layers handle this.  in fact it's probably an error */
  		return code;
  		}
  
  	if ( ! SSL_in_init(s))  /* done, no need to send a retransmit */
  		{
  		BIO_set_flags(SSL_get_rbio(s), BIO_FLAGS_READ);
  		return code;
  		}
  
  #if 0 /* for now, each alert contains only one record number */
  	item = pqueue_peek(state->rcvd_records);
  	if ( item )
  		{
  		/* send an alert immediately for all the missing records */
  		}
  	else
  #endif
  
  #if 0  /* no more alert sending, just retransmit the last set of messages */
  	if ( state->timeout.read_timeouts >= DTLS1_TMO_READ_COUNT)
  		ssl3_send_alert(s,SSL3_AL_WARNING,
  			DTLS1_AD_MISSING_HANDSHAKE_MESSAGE);
  #endif
  
  	return dtls1_handle_timeout(s);
  	}
  
  int
  dtls1_get_queue_priority(unsigned short seq, int is_ccs)
  	{
  	/* The index of the retransmission queue actually is the message sequence number,
  	 * since the queue only contains messages of a single handshake. However, the
  	 * ChangeCipherSpec has no message sequence number and so using only the sequence
  	 * will result in the CCS and Finished having the same index. To prevent this,
  	 * the sequence number is multiplied by 2. In case of a CCS 1 is subtracted.
  	 * This does not only differ CSS and Finished, it also maintains the order of the
  	 * index (important for priority queues) and fits in the unsigned short variable.
  	 */	
  	return seq * 2 - is_ccs;
  	}
  
  int
  dtls1_retransmit_buffered_messages(SSL *s)
  	{
  	pqueue sent = s->d1->sent_messages;
  	piterator iter;
  	pitem *item;
  	hm_fragment *frag;
  	int found = 0;
  
  	iter = pqueue_iterator(sent);
  
  	for ( item = pqueue_next(&iter); item != NULL; item = pqueue_next(&iter))
  		{
  		frag = (hm_fragment *)item->data;
  			if ( dtls1_retransmit_message(s,
  				(unsigned short)dtls1_get_queue_priority(frag->msg_header.seq, frag->msg_header.is_ccs),
  				0, &found) <= 0 && found)
  			{
  			fprintf(stderr, "dtls1_retransmit_message() failed\n");
  			return -1;
  			}
  		}
  
  	return 1;
  	}
  
  int
  dtls1_buffer_message(SSL *s, int is_ccs)
  	{
  	pitem *item;
  	hm_fragment *frag;
  	PQ_64BIT seq64;
  
  	/* this function is called immediately after a message has 
  	 * been serialized */
  	OPENSSL_assert(s->init_off == 0);
  
  	frag = dtls1_hm_fragment_new(s->init_num, 0);
  
  	memcpy(frag->fragment, s->init_buf->data, s->init_num);
  
  	if ( is_ccs)
  		{
  		OPENSSL_assert(s->d1->w_msg_hdr.msg_len + 
  			DTLS1_CCS_HEADER_LENGTH <= (unsigned int)s->init_num);
  		}
  	else
  		{
  		OPENSSL_assert(s->d1->w_msg_hdr.msg_len + 
  			DTLS1_HM_HEADER_LENGTH == (unsigned int)s->init_num);
  		}
  
  	frag->msg_header.msg_len = s->d1->w_msg_hdr.msg_len;
  	frag->msg_header.seq = s->d1->w_msg_hdr.seq;
  	frag->msg_header.type = s->d1->w_msg_hdr.type;
  	frag->msg_header.frag_off = 0;
  	frag->msg_header.frag_len = s->d1->w_msg_hdr.msg_len;
  	frag->msg_header.is_ccs = is_ccs;
  
  	/* save current state*/
  	frag->msg_header.saved_retransmit_state.enc_write_ctx = s->enc_write_ctx;
  	frag->msg_header.saved_retransmit_state.write_hash = s->write_hash;
  	frag->msg_header.saved_retransmit_state.compress = s->compress;
  	frag->msg_header.saved_retransmit_state.session = s->session;
  	frag->msg_header.saved_retransmit_state.epoch = s->d1->w_epoch;
  
  	pq_64bit_init(&seq64);
  
  	pq_64bit_assign_word(&seq64,
  						 dtls1_get_queue_priority(frag->msg_header.seq,
  												  frag->msg_header.is_ccs));
  		
  	item = pitem_new(seq64, frag);
  	pq_64bit_free(&seq64);
  	if ( item == NULL)
  		{
  		dtls1_hm_fragment_free(frag);
  		return 0;
  		}
  
  #if 0
  	fprintf( stderr, "buffered messge: \ttype = %xx\n", msg_buf->type);
  	fprintf( stderr, "\t\t\t\t\tlen = %d\n", msg_buf->len);
  	fprintf( stderr, "\t\t\t\t\tseq_num = %d\n", msg_buf->seq_num);
  #endif
  
  	pqueue_insert(s->d1->sent_messages, item);
  	return 1;
  	}
  
  int
  dtls1_retransmit_message(SSL *s, unsigned short seq, unsigned long frag_off,
  	int *found)
  	{
  	int ret;
  	/* XDTLS: for now assuming that read/writes are blocking */
  	pitem *item;
  	hm_fragment *frag ;
  	unsigned long header_length;
  	PQ_64BIT seq64;
  	struct dtls1_retransmit_state saved_state;
  	unsigned char save_write_sequence[8];
  
  	/*
  	  OPENSSL_assert(s->init_num == 0);
  	  OPENSSL_assert(s->init_off == 0);
  	 */
  
  	/* XDTLS:  the requested message ought to be found, otherwise error */
  	pq_64bit_init(&seq64);
  	pq_64bit_assign_word(&seq64, seq);
  
  	item = pqueue_find(s->d1->sent_messages, seq64);
  	pq_64bit_free(&seq64);
  	if ( item == NULL)
  		{
  		fprintf(stderr, "retransmit:  message %d non-existant\n", seq);
  		*found = 0;
  		return 0;
  		}
  
  	*found = 1;
  	frag = (hm_fragment *)item->data;
  
  	if ( frag->msg_header.is_ccs)
  		header_length = DTLS1_CCS_HEADER_LENGTH;
  	else
  		header_length = DTLS1_HM_HEADER_LENGTH;
  
  	memcpy(s->init_buf->data, frag->fragment, 
  		frag->msg_header.msg_len + header_length);
  		s->init_num = frag->msg_header.msg_len + header_length;
  
  	dtls1_set_message_header_int(s, frag->msg_header.type, 
  		frag->msg_header.msg_len, frag->msg_header.seq, 0, 
  		frag->msg_header.frag_len);
  
  	/* save current state */
  	saved_state.enc_write_ctx = s->enc_write_ctx;
  	saved_state.write_hash = s->write_hash;
  	saved_state.compress = s->compress;
  	saved_state.session = s->session;
  	saved_state.epoch = s->d1->w_epoch;
  	saved_state.epoch = s->d1->w_epoch;
  	
  	s->d1->retransmitting = 1;
  	
  	/* restore state in which the message was originally sent */
  	s->enc_write_ctx = frag->msg_header.saved_retransmit_state.enc_write_ctx;
  	s->write_hash = frag->msg_header.saved_retransmit_state.write_hash;
  	s->compress = frag->msg_header.saved_retransmit_state.compress;
  	s->session = frag->msg_header.saved_retransmit_state.session;
  	s->d1->w_epoch = frag->msg_header.saved_retransmit_state.epoch;
  	
  	if (frag->msg_header.saved_retransmit_state.epoch == saved_state.epoch - 1)
  	{
  		memcpy(save_write_sequence, s->s3->write_sequence, sizeof(s->s3->write_sequence));
  		memcpy(s->s3->write_sequence, s->d1->last_write_sequence, sizeof(s->s3->write_sequence));
  	}
  	
  	ret = dtls1_do_write(s, frag->msg_header.is_ccs ? 
  						 SSL3_RT_CHANGE_CIPHER_SPEC : SSL3_RT_HANDSHAKE);
  	
  	/* restore current state */
  	s->enc_write_ctx = saved_state.enc_write_ctx;
  	s->write_hash = saved_state.write_hash;
  	s->compress = saved_state.compress;
  	s->session = saved_state.session;
  	s->d1->w_epoch = saved_state.epoch;
  	
  	if (frag->msg_header.saved_retransmit_state.epoch == saved_state.epoch - 1)
  	{
  		memcpy(s->d1->last_write_sequence, s->s3->write_sequence, sizeof(s->s3->write_sequence));
  		memcpy(s->s3->write_sequence, save_write_sequence, sizeof(s->s3->write_sequence));
  	}
  
  	s->d1->retransmitting = 0;
  
  	(void)BIO_flush(SSL_get_wbio(s));
  	return ret;
  	}
  
  /* call this function when the buffered messages are no longer needed */
  void
  dtls1_clear_record_buffer(SSL *s)
  	{
  	pitem *item;
  
  	for(item = pqueue_pop(s->d1->sent_messages);
  		item != NULL; item = pqueue_pop(s->d1->sent_messages))
  		{
  		dtls1_hm_fragment_free((hm_fragment *)item->data);
  		pitem_free(item);
  		}
  	}
  
  
  unsigned char *
  dtls1_set_message_header(SSL *s, unsigned char *p, unsigned char mt,
  			unsigned long len, unsigned long frag_off, unsigned long frag_len)
  	{
  	/* Don't change sequence numbers while listening */
  	if (frag_off == 0 && !s->d1->listen)
  		{
  		s->d1->handshake_write_seq = s->d1->next_handshake_write_seq;
  		s->d1->next_handshake_write_seq++;
  		}
  
  	dtls1_set_message_header_int(s, mt, len, s->d1->handshake_write_seq,
  		frag_off, frag_len);
  
  	return p += DTLS1_HM_HEADER_LENGTH;
  	}
  
  
  /* don't actually do the writing, wait till the MTU has been retrieved */
  static 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)
  	{
  	struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
  
  	msg_hdr->type = mt;
  	msg_hdr->msg_len = len;
  	msg_hdr->seq = seq_num;
  	msg_hdr->frag_off = frag_off;
  	msg_hdr->frag_len = frag_len;
  	}
  
  static void
  dtls1_fix_message_header(SSL *s, unsigned long frag_off,
  			unsigned long frag_len)
  	{
  	struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
  
  	msg_hdr->frag_off = frag_off;
  	msg_hdr->frag_len = frag_len;
  	}
  
  static unsigned char *
  dtls1_write_message_header(SSL *s, unsigned char *p)
  	{
  	struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
  
  	*p++ = msg_hdr->type;
  	l2n3(msg_hdr->msg_len, p);
  
  	s2n(msg_hdr->seq, p);
  	l2n3(msg_hdr->frag_off, p);
  	l2n3(msg_hdr->frag_len, p);
  
  	return p;
  	}
  
  unsigned int 
  dtls1_min_mtu(void)
  	{
  	return (g_probable_mtu[(sizeof(g_probable_mtu) / 
  		sizeof(g_probable_mtu[0])) - 1]);
  	}
  
  static unsigned int 
  dtls1_guess_mtu(unsigned int curr_mtu)
  	{
  	size_t i;
  
  	if ( curr_mtu == 0 )
  		return g_probable_mtu[0] ;
  
  	for ( i = 0; i < sizeof(g_probable_mtu)/sizeof(g_probable_mtu[0]); i++)
  		if ( curr_mtu > g_probable_mtu[i])
  			return g_probable_mtu[i];
  
  	return curr_mtu;
  	}
  
  void
  dtls1_get_message_header(unsigned char *data, struct hm_header_st *msg_hdr)
  	{
  	memset(msg_hdr, 0x00, sizeof(struct hm_header_st));
  	msg_hdr->type = *(data++);
  	n2l3(data, msg_hdr->msg_len);
  
  	n2s(data, msg_hdr->seq);
  	n2l3(data, msg_hdr->frag_off);
  	n2l3(data, msg_hdr->frag_len);
  	}
  
  void
  dtls1_get_ccs_header(unsigned char *data, struct ccs_header_st *ccs_hdr)
  	{
  	memset(ccs_hdr, 0x00, sizeof(struct ccs_header_st));
  
  	ccs_hdr->type = *(data++);
  	}
  