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>
  
  
  /* XDTLS:  figure out the right values */
  static unsigned int g_probable_mtu[] = {1500 - 28, 512 - 28, 256 - 28};
  
  static unsigned int dtls1_min_mtu(void);
  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 int dtls1_retransmit_buffered_messages(SSL *s);
  static long dtls1_get_message_fragment(SSL *s, int st1, int stn, 
      long max, int *ok);
  static void dtls1_process_handshake_fragment(SSL *s, int frag_len);
  
  static hm_fragment *
  dtls1_hm_fragment_new(unsigned long frag_len)
      {
      hm_fragment *frag = NULL;
      unsigned char *buf = NULL;
  
      frag = (hm_fragment *)OPENSSL_malloc(sizeof(hm_fragment));
      if ( frag == NULL)
          return NULL;
  
      buf = (unsigned char *)OPENSSL_malloc(frag_len 
          + DTLS1_HM_HEADER_LENGTH);
      if ( buf == NULL)
          {
          OPENSSL_free(frag);
          return NULL;
          }
      
      frag->fragment = buf;
  
      return frag;
      }
  
  static void
  dtls1_hm_fragment_free(hm_fragment *frag)
      {
      OPENSSL_free(frag->fragment);
      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;
  
  	/* AHA!  Figure out the MTU, and stick to the right size */
  	if ( ! (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);
  		}
  
  	OPENSSL_assert(mtu > 0);  /* should have something reasonable now */
  
  #endif
  
  	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);
  
  	frag_off = 0;
  	while( s->init_num)
  		{
  		curr_mtu = s->d1->mtu - BIO_wpending(SSL_get_wbio(s)) - 
  			DTLS1_RT_HEADER_LENGTH;
  
  		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;
  			}
  
  		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))
  				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 */
  				ssl3_finish_mac(s, 
  					(unsigned char *)&s->init_buf->data[s->init_off + 
  						DTLS1_HM_HEADER_LENGTH], ret - DTLS1_HM_HEADER_LENGTH);
  			
  			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;
  
  	/* 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;
  		}
  	
  	do
  		{
  		if ( s->d1->r_msg_hdr.frag_off == 0)
  			{
  			/* s->d1->r_message_header.msg_len = 0; */
  			memset(&(s->d1->r_msg_hdr), 0x00, sizeof(struct hm_header_st));
  			}
  
  		i = dtls1_get_message_fragment(s, st1, stn, max, ok);
  		if ( i == DTLS1_HM_BAD_FRAGMENT ||
              i == DTLS1_HM_FRAGMENT_RETRY)  /* bad fragment received */
  			continue;
  		else if ( i <= 0 && !*ok)
  			return i;
  
  		if (s->d1->r_msg_hdr.msg_len == (unsigned int)s->init_num - DTLS1_HM_HEADER_LENGTH)
  			{
  			memset(&(s->d1->r_msg_hdr), 0x00, sizeof(struct hm_header_st));
  
  			s->d1->handshake_read_seq++;
  			/* we just read a handshake message from the other side:
  			 * this means that we don't need to retransmit of the
  			 * buffered messages.  
  			 * XDTLS: may be able clear out this
  			 * buffer a little sooner (i.e if an out-of-order
  			 * handshake message/record is received at the record
  			 * layer.  
  			 * XDTLS: exception is that the server needs to
  			 * know that change cipher spec and finished messages
  			 * have been received by the client before clearing this
  			 * buffer.  this can simply be done by waiting for the
  			 * first data  segment, but is there a better way?  */
  			dtls1_clear_record_buffer(s);
  
              s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
  			return s->init_num - DTLS1_HM_HEADER_LENGTH;
  			}
  		else
  			s->d1->r_msg_hdr.frag_off = i;
  		} while(1) ;
  
  f_err:
  	ssl3_send_alert(s,SSL3_AL_FATAL,al);
  	*ok = 0;
  	return -1;
  	}
  
  
  static int
  dtls1_retrieve_buffered_fragment(SSL *s, unsigned long *copied)
      {
      /* (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;
      unsigned long overlap;
      unsigned char *p;
  
      item = pqueue_peek(s->d1->buffered_messages);
      if ( item == NULL)
          return 0;
  
      frag = (hm_fragment *)item->data;
      
      if ( s->d1->handshake_read_seq == frag->msg_header.seq &&
          frag->msg_header.frag_off <= (unsigned int)s->init_num - DTLS1_HM_HEADER_LENGTH)
          {
          pqueue_pop(s->d1->buffered_messages);
          overlap = s->init_num - DTLS1_HM_HEADER_LENGTH 
              - frag->msg_header.frag_off;
  
          p = frag->fragment;
  
          memcpy(&s->init_buf->data[s->init_num],
              p + DTLS1_HM_HEADER_LENGTH + overlap,
              frag->msg_header.frag_len - overlap);
      
          OPENSSL_free(frag->fragment);
          OPENSSL_free(frag);
          pitem_free(item);
  
          *copied = frag->msg_header.frag_len - overlap;
          return *copied;
          }
      else
          return 0;
      }
  
  
  static int
  dtls1_buffer_handshake_fragment(SSL *s, struct hm_header_st* msg_hdr)
  {
      hm_fragment *frag = NULL;
      pitem *item = NULL;
  	PQ_64BIT seq64;
  
      frag = dtls1_hm_fragment_new(msg_hdr->frag_len);
      if ( frag == NULL)
          goto err;
  
      memcpy(frag->fragment, &(s->init_buf->data[s->init_num]),
          msg_hdr->frag_len + DTLS1_HM_HEADER_LENGTH);
  
      memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
  
      pq_64bit_init(&seq64);
      pq_64bit_assign_word(&seq64, msg_hdr->seq);
  
      item = pitem_new(seq64, frag);
      if ( item == NULL)
          goto err;
  
      pq_64bit_free(&seq64);
  
      pqueue_insert(s->d1->buffered_messages, item);
      return 1;
  
  err:
      if ( frag != NULL) dtls1_hm_fragment_free(frag);
      if ( item != NULL) OPENSSL_free(item);
      return 0;
  }
  
  
  static void
  dtls1_process_handshake_fragment(SSL *s, int frag_len)
      {
      unsigned char *p;
  
      p = (unsigned char *)s->init_buf->data;
  
  	ssl3_finish_mac(s, &p[s->init_num - frag_len], frag_len);
      }
  
  
  static int
  dtls1_process_out_of_seq_message(SSL *s, struct hm_header_st *msg_hdr, int *ok)
      {
      int i;
      unsigned char *p;
  
      /* make sure there's enough room to read this fragment */
      if ( (int)msg_hdr->frag_len && !BUF_MEM_grow_clean(s->init_buf, 
               (int)msg_hdr->frag_len + DTLS1_HM_HEADER_LENGTH + s->init_num))
          {
          SSLerr(SSL_F_DTLS1_PROCESS_OUT_OF_SEQ_MESSAGE,ERR_R_BUF_LIB);
          goto err;
          }
  
      p = (unsigned char *)s->init_buf->data;
  
      /* read the body of the fragment (header has already been read */
      if ( msg_hdr->frag_len > 0)
  		{
  		i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
              &p[s->init_num], 
              msg_hdr->frag_len,0);
  		if (i <= 0)
  			{
  			*ok = 0;
  			return i;
  			}
  		}
  
      if ( msg_hdr->seq > s->d1->handshake_read_seq)
          dtls1_buffer_handshake_fragment(s, msg_hdr);
      else
          OPENSSL_assert(msg_hdr->seq < s->d1->handshake_read_seq);
  
      return DTLS1_HM_FRAGMENT_RETRY;
  err:
      *ok = 0;
      return -1;
      }
  
  
  static long
  dtls1_get_message_fragment(SSL *s, int st1, int stn, long max, int *ok)
  	{
  	unsigned char *p;
  	unsigned long l, frag_off, frag_len;
  	int i,al;
  	struct hm_header_st msg_hdr;
      unsigned long overlap;
      
      /* see if we have the required fragment already */
      if (dtls1_retrieve_buffered_fragment(s, &l))
      {
          /* compute MAC, remove fragment headers */
          dtls1_process_handshake_fragment(s, l);
          s->init_msg = s->init_buf->data + DTLS1_HM_HEADER_LENGTH;
          s->state = stn;
          return 1;
      }
  
      /* get a handshake fragment from the record layer */
  	p = (unsigned char *)s->init_buf->data;
  
      /* read handshake message header */
  	i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,&p[s->init_num],
  		DTLS1_HM_HEADER_LENGTH, 0);
  	if (i <= 0) 	/* nbio, or an error */
  		{
  		s->rwstate=SSL_READING;
  		*ok = 0;
  		return i;
  		}
  
  	OPENSSL_assert(i == DTLS1_HM_HEADER_LENGTH);
  
  	p += s->init_num;
      /* parse the message fragment header */
      
      dtls1_get_message_header(p, &msg_hdr);
  
      /* 
       * if this is a future (or stale) message it gets buffered
       * (or dropped)--no further processing at this time 
       */
      if ( msg_hdr.seq != s->d1->handshake_read_seq)
          return dtls1_process_out_of_seq_message(s, &msg_hdr, ok);
  
      l = msg_hdr.msg_len;
      frag_off = msg_hdr.frag_off;
  	frag_len = msg_hdr.frag_len;
  
      /* sanity checking */
      if ( frag_off + frag_len > l)
          {
          al=SSL_AD_ILLEGAL_PARAMETER;
          SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
          goto f_err;
          }
  
  	if (!s->server && s->d1->r_msg_hdr.frag_off == 0 &&
          p[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 (p[1] == 0 && p[2] == 0 &&p[3] == 0)
              {
              if (s->msg_callback)
                  s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, 
                      p, 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;
              }
          }
  
      /* XDTLS: do a sanity check on the fragment */
  
      s->init_num += i;
  
  	if ( s->d1->r_msg_hdr.frag_off == 0) /* first fragment */
  		{
  		/* BUF_MEM_grow takes an 'int' parameter */
  		if (l > (INT_MAX-DTLS1_HM_HEADER_LENGTH)) 
  			{
  			al=SSL_AD_ILLEGAL_PARAMETER;
  			SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
  			goto f_err;
  			}
  		if (l && !BUF_MEM_grow_clean(s->init_buf,(int)l
  			+ DTLS1_HM_HEADER_LENGTH))
  			{
  			SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,ERR_R_BUF_LIB);
  			goto err;
  			}
          /* Only do this test when we're reading the expected message.
           * Stale messages will be dropped and future messages will be buffered */
          if ( l > (unsigned long)max)
  			{
  			al=SSL_AD_ILLEGAL_PARAMETER;
  			SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
  			goto f_err;
  			}
  
  		s->s3->tmp.message_size=l;
  		}
  
      if ( frag_len > (unsigned long)max)
          {
          al=SSL_AD_ILLEGAL_PARAMETER;
          SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
          goto f_err;
          }
      if ( frag_len + s->init_num > (INT_MAX - DTLS1_HM_HEADER_LENGTH))
          {
          al=SSL_AD_ILLEGAL_PARAMETER;
          SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,SSL_R_EXCESSIVE_MESSAGE_SIZE);
          goto f_err;
          }
  
      if ( frag_len & !BUF_MEM_grow_clean(s->init_buf, (int)frag_len 
               + DTLS1_HM_HEADER_LENGTH + s->init_num))
          {
          SSLerr(SSL_F_DTLS1_GET_MESSAGE_FRAGMENT,ERR_R_BUF_LIB);
          goto err;
          }
  
  	if ( s->d1->r_msg_hdr.frag_off == 0)
  		{
  		s->s3->tmp.message_type = msg_hdr.type;
  		s->d1->r_msg_hdr.type = msg_hdr.type;
  		s->d1->r_msg_hdr.msg_len = l;
  		/* s->d1->r_msg_hdr.seq = seq_num; */
  		}
  
  	/* XDTLS:  ressurect this when restart is in place */
  	s->state=stn;
  	
  	/* next state (stn) */
  	p = (unsigned char *)s->init_buf->data;
  
  	if ( frag_len > 0)
  		{
  		i=s->method->ssl_read_bytes(s,SSL3_RT_HANDSHAKE,
              &p[s->init_num], 
              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 */
  	OPENSSL_assert(i == (int)frag_len);
  
  #if 0
      /* Successfully read a fragment.
       * It may be (1) out of order, or
       *           (2) it's a repeat, in which case we dump it
       *           (3) the one we are expecting next (maybe with overlap)
       * If it is next one, it may overlap with previously read bytes
       */
  
      /* case (1): buffer the future fragment 
       * (we can treat fragments from a future message the same
       * as future fragments from the message being currently read, since
       * they are sematically simply out of order.
       */
      if ( msg_hdr.seq > s->d1->handshake_read_seq ||
          frag_off > s->init_num - DTLS1_HM_HEADER_LENGTH)
      {
          dtls1_buffer_handshake_fragment(s, &msg_hdr);
          return DTLS1_HM_FRAGMENT_RETRY;
      }
  
      /* case (2):  drop the entire fragment, and try again */
      if ( msg_hdr.seq < s->d1->handshake_read_seq ||
          frag_off + frag_len < s->init_num - DTLS1_HM_HEADER_LENGTH)
          {
          s->init_num -= DTLS1_HM_HEADER_LENGTH;
          return DTLS1_HM_FRAGMENT_RETRY;
          }
  #endif
  
      /* case (3): received a immediately useful fragment.  Determine the 
       * possible overlap and copy the fragment.
       */
      overlap = (s->init_num - DTLS1_HM_HEADER_LENGTH) - frag_off;
          
      /* retain the header for the first fragment */
      if ( s->init_num > DTLS1_HM_HEADER_LENGTH)
          {
          memmove(&(s->init_buf->data[s->init_num]),
              &(s->init_buf->data[s->init_num + DTLS1_HM_HEADER_LENGTH + overlap]),
              frag_len - overlap);
  
          s->init_num += frag_len - overlap;
          }
      else
          s->init_num += frag_len;
  
      dtls1_process_handshake_fragment(s, frag_len - overlap);
  
  	if (s->msg_callback)
  		s->msg_callback(0, s->version, SSL3_RT_HANDSHAKE, s->init_buf->data, 
  			(size_t)s->init_num, s, 
  			s->msg_callback_arg);
  	*ok=1;
  
  	return s->init_num;
  
  f_err:
  	ssl3_send_alert(s,SSL3_AL_FATAL,al);
      s->init_num = 0;
  err:
  	*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;
  
  #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->d1->next_handshake_write_seq++;
  		s2n(s->d1->handshake_write_seq,p);
  
  		s->init_num=DTLS1_CCS_HEADER_LENGTH;
  		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));
  	}
  
  unsigned long dtls1_output_cert_chain(SSL *s, X509 *x)
  	{
  	unsigned char *p;
  	int n,i;
  	unsigned long l= 3 + DTLS1_HM_HEADER_LENGTH;
  	BUF_MEM *buf;
  	X509_STORE_CTX xs_ctx;
  	X509_OBJECT obj;
  
  	/* 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)
  		{
  		if(!X509_STORE_CTX_init(&xs_ctx,s->ctx->cert_store,NULL,NULL))
  			{
  			SSLerr(SSL_F_DTLS1_OUTPUT_CERT_CHAIN,ERR_R_X509_LIB);
  			return(0);
  			}
  
  		for (;;)
  			{
  			n=i2d_X509(x,NULL);
  			if (!BUF_MEM_grow_clean(buf,(int)(n+l+3)))
  				{
  				SSLerr(SSL_F_DTLS1_OUTPUT_CERT_CHAIN,ERR_R_BUF_LIB);
  				return(0);
  				}
  			p=(unsigned char *)&(buf->data[l]);
  			l2n3(n,p);
  			i2d_X509(x,&p);
  			l+=n+3;
  			if (X509_NAME_cmp(X509_get_subject_name(x),
  				X509_get_issuer_name(x)) == 0) break;
  
  			i=X509_STORE_get_by_subject(&xs_ctx,X509_LU_X509,
  				X509_get_issuer_name(x),&obj);
  			if (i <= 0) break;
  			x=obj.data.x509;
  			/* Count is one too high since the X509_STORE_get uped the
  			 * ref count */
  			X509_free(x);
  			}
  
  		X509_STORE_CTX_cleanup(&xs_ctx);
  		}
  
  	/* Thawte special :-) */
  	if (s->ctx->extra_certs != NULL)
  	for (i=0; i<sk_X509_num(s->ctx->extra_certs); i++)
  		{
  		x=sk_X509_value(s->ctx->extra_certs,i);
  		n=i2d_X509(x,NULL);
  		if (!BUF_MEM_grow_clean(buf,(int)(n+l+3)))
  			{
  			SSLerr(SSL_F_DTLS1_OUTPUT_CERT_CHAIN,ERR_R_BUF_LIB);
  			return(0);
  			}
  		p=(unsigned char *)&(buf->data[l]);
  		l2n3(n,p);
  		i2d_X509(x,&p);
  		l+=n+3;
  		}
  
  	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)
      {
      DTLS1_STATE *state;
      BIO *bio;
      int send_alert = 0;
  
      if ( code > 0)
          {
          fprintf( stderr, "invalid state reached %s:%d", __FILE__, __LINE__);
          return 1;
          }
  
      bio = SSL_get_rbio(s);
      if ( ! BIO_dgram_recv_timedout(bio))
          {
          /* 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;
          }
  
      state = s->d1;
      state->timeout.num_alerts++;
      if ( state->timeout.num_alerts > DTLS1_TMO_ALERT_COUNT)
          {
          /* fail the connection, enough alerts have been sent */
          SSLerr(SSL_F_DTLS1_READ_FAILED,SSL_R_READ_TIMEOUT_EXPIRED);
          return 0;
          }
  	
      state->timeout.read_timeouts++;
      if ( state->timeout.read_timeouts > DTLS1_TMO_READ_COUNT)
          {
          send_alert = 1;
          state->timeout.read_timeouts = 1;
          }
  
  	
  #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 ( send_alert)
              ssl3_send_alert(s,SSL3_AL_WARNING,
                  DTLS1_AD_MISSING_HANDSHAKE_MESSAGE);
  #endif
  
      return dtls1_retransmit_buffered_messages(s) ;
      }
  
  
  static 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, frag->msg_header.seq, 0, &found) <= 0 &&
              found)
              {
              fprintf(stderr, "dtls1_retransmit_message() failed\n");
              return -1;
              }
          }
  
      return 1;
      }
  
  #if 0
  static dtls1_message_buffer *
  dtls1_message_buffer_new(unsigned int len)
      {
      dtls1_message_buffer *msg_buf;
  
      msg_buf = (dtls1_message_buffer *) 
          OPENSSL_malloc(sizeof(dtls1_message_buffer)); 
      if ( msg_buf == NULL)
          return NULL;
  
      memset(msg_buf, 0x00, sizeof(dtls1_message_buffer));
  
      msg_buf->data = (unsigned char *) OPENSSL_malloc(len);
      if ( msg_buf->data == NULL)
          {
          OPENSSL_free(msg_buf);
          return NULL;
          }
  
      memset(msg_buf->data, 0x00, len);
      return msg_buf;
      }
  #endif
  
  #if 0
  static void
  dtls1_message_buffer_free(dtls1_message_buffer *msg_buf)
      {
      if (msg_buf != NULL)
          {
          OPENSSL_free(msg_buf->data);
          OPENSSL_free(msg_buf);
          }
      }
  #endif
  
  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);
  
      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;
  
      pq_64bit_init(&seq64);
      pq_64bit_assign_word(&seq64, frag->msg_header.seq);
  
      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;
  
      /*
        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);
  
      s->d1->retransmitting = 1;
      ret = dtls1_do_write(s, frag->msg_header.is_ccs ? 
          SSL3_RT_CHANGE_CIPHER_SPEC : SSL3_RT_HANDSHAKE);
      s->d1->retransmitting = 0;
  
      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)
      {
      if ( frag_off == 0)
          {
          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;
      }
  
  static 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++);
      n2s(data, ccs_hdr->seq);
  }
  