Move s->packet and s->packet_length into s->rlayer
[openssl.git] / ssl / d1_both.c
index 7ca3405..587eb9e 100644 (file)
@@ -1,7 +1,7 @@
 /* ssl/d1_both.c */
-/* 
+/*
  * DTLS implementation written by Nagendra Modadugu
- * (nagendra@cs.stanford.edu) for the OpenSSL project 2005.  
+ * (nagendra@cs.stanford.edu) for the OpenSSL project 2005.
  */
 /* ====================================================================
  * Copyright (c) 1998-2005 The OpenSSL Project.  All rights reserved.
@@ -11,7 +11,7 @@
  * are met:
  *
  * 1. Redistributions of source code must retain the above copyright
- *    notice, this list of conditions and the following disclaimer. 
+ *    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
  * 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:
  *     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 
+ * 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
  * 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
 #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; } }
+
+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_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 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)
-       {
-       hm_fragment *frag = NULL;
-       unsigned char *buf = 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;
-
-       return frag;
-       }
+static const unsigned int g_probable_mtu[] = { 1500, 512, 256 };
 
-static void
-dtls1_hm_fragment_free(hm_fragment *frag)
-       {
-       if (frag->fragment) OPENSSL_free(frag->fragment);
-       OPENSSL_free(frag);
-       }
+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;
+}
+
+void dtls1_hm_fragment_free(hm_fragment *frag)
+{
 
-/* send s->init_buf in records of type 'type' (SSL3_RT_HANDSHAKE or SSL3_RT_CHANGE_CIPHER_SPEC) */
+    if (frag->msg_header.is_ccs) {
+        EVP_CIPHER_CTX_free(frag->msg_header.
+                            saved_retransmit_state.enc_write_ctx);
+        EVP_MD_CTX_destroy(frag->msg_header.
+                           saved_retransmit_state.write_hash);
+    }
+    if (frag->fragment)
+        OPENSSL_free(frag->fragment);
+    if (frag->reassembly)
+        OPENSSL_free(frag->reassembly);
+    OPENSSL_free(frag);
+}
+
+static int dtls1_query_mtu(SSL *s)
+{
+    if (s->d1->link_mtu) {
+        s->d1->mtu =
+            s->d1->link_mtu - BIO_dgram_get_mtu_overhead(SSL_get_wbio(s));
+        s->d1->link_mtu = 0;
+    }
+
+    /* AHA!  Figure out the MTU, and stick to the right size */
+    if (s->d1->mtu < dtls1_min_mtu(s)) {
+        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)) {
+                /* Set to min mtu */
+                s->d1->mtu = dtls1_min_mtu(s);
+                BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SET_MTU,
+                         s->d1->mtu, NULL);
+            }
+        } else
+            return 0;
+    }
+    return 1;
+}
+
+/*
+ * 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 ( ! (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);
-
-       if (s->write_hash)
-               mac_size = EVP_MD_CTX_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->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.
+{
+    int ret;
+    unsigned int curr_mtu;
+    int retry = 1;
+    unsigned int len, frag_off, mac_size, blocksize, used_len;
+
+    if (!dtls1_query_mtu(s))
+        return -1;
+
+    OPENSSL_assert(s->d1->mtu >= dtls1_min_mtu(s)); /* 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) {
+        if (s->enc_write_ctx
+            && EVP_CIPHER_CTX_mode(s->enc_write_ctx) == EVP_CIPH_GCM_MODE)
+            mac_size = 0;
+        else
+            mac_size = EVP_MD_CTX_size(s->write_hash);
+    } else
+        mac_size = 0;
+
+    if (s->enc_write_ctx &&
+        (EVP_CIPHER_CTX_mode(s->enc_write_ctx) == EVP_CIPH_CBC_MODE))
+        blocksize = 2 * EVP_CIPHER_block_size(s->enc_write_ctx->cipher);
+    else
+        blocksize = 0;
+
+    frag_off = 0;
+    /* s->init_num shouldn't ever be < 0...but just in case */
+    while (s->init_num > 0) {
+        used_len = BIO_wpending(SSL_get_wbio(s)) + DTLS1_RT_HEADER_LENGTH
+            + mac_size + blocksize;
+        if (s->d1->mtu > used_len)
+            curr_mtu = s->d1->mtu - used_len;
+        else
+            curr_mtu = 0;
+
+        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;
+            used_len = DTLS1_RT_HEADER_LENGTH + mac_size + blocksize;
+            if (s->d1->mtu > used_len + DTLS1_HM_HEADER_LENGTH) {
+                curr_mtu = s->d1->mtu - used_len;
+            } else {
+                /* Shouldn't happen */
+                return -1;
+            }
+        }
+
+        /*
+         * We just checked that s->init_num > 0 so this cast should be safe
+         */
+        if (((unsigned int)s->init_num) > curr_mtu)
+            len = curr_mtu;
+        else
+            len = s->init_num;
+
+        /* Shouldn't ever happen */
+        if (len > INT_MAX)
+            len = INT_MAX;
+
+        /*
+         * 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;
+
+                /*
+                 * We just checked that s->init_num > 0 so this cast should
+                 * be safe
+                 */
+                if (((unsigned int)s->init_num) > curr_mtu)
+                    len = curr_mtu;
+                else
+                    len = s->init_num;
+            }
+
+            /* Shouldn't ever happen */
+            if (len > INT_MAX)
+                len = INT_MAX;
+
+            if (len < DTLS1_HM_HEADER_LENGTH) {
+                /*
+                 * len is so small that we really can't do anything sensible
+                 * so fail
+                 */
+                return -1;
+            }
+            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]);
+        }
+
+        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 (retry && BIO_ctrl(SSL_get_wbio(s),
+                                  BIO_CTRL_DGRAM_MTU_EXCEEDED, 0, NULL) > 0) {
+                if (!(SSL_get_options(s) & SSL_OP_NO_QUERY_MTU)) {
+                    if (!dtls1_query_mtu(s))
+                        return -1;
+                    /* Have one more go */
+                    retry = 0;
+                } else
+                    return -1;
+            } 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->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;
-
-       /* 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;
-       do
-               {
-               if ( msg_hdr->frag_off == 0)
-                       {
-                       /* s->d1->r_message_header.msg_len = 0; */
-                       memset(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;
-
-               /* Note that s->init_sum is used 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. Overlapping fragments would cause
-                * premature termination, so we don't expect overlaps.
-                * Well, handling overlaps would require something more
-                * drastic. Indeed, as it is now there is no way to
-                * tell if out-of-order fragment from the middle was
-                * the last. '>=' is the best/least we can do to control
-                * the potential damage caused by malformed overlaps. */
-               if ((unsigned int)s->init_num >= msg_hdr->msg_len)
-                       {
-                       unsigned char *p = (unsigned char *)s->init_buf->data;
-                       unsigned long msg_len = msg_hdr->msg_len;
-
-                       /* reconstruct message header as if it was
-                        * sent in single fragment */
-                       *(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));
-
-                       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;
-                       }
-               else
-                       msg_hdr->frag_off = i;
-               } while(1) ;
-
-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,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 */
-       }
-
+{
+    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, 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;
+}
+
+/*
+ * dtls1_max_handshake_message_len returns the maximum number of bytes
+ * permitted in a DTLS handshake message for |s|. The minimum is 16KB, but
+ * may be greater if the maximum certificate list size requires it.
+ */
+static unsigned long dtls1_max_handshake_message_len(const SSL *s)
+{
+    unsigned long max_len =
+        DTLS1_HM_HEADER_LENGTH + SSL3_RT_MAX_ENCRYPTED_LENGTH;
+    if (max_len < (unsigned long)s->max_cert_list)
+        return s->max_cert_list;
+    return max_len;
+}
 
 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;
-
-       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;
-       }
-
+dtls1_reassemble_fragment(SSL *s, const struct hm_header_st *msg_hdr, int *ok)
+{
+    hm_fragment *frag = NULL;
+    pitem *item = NULL;
+    int i = -1, is_complete;
+    unsigned char seq64be[8];
+    unsigned long frag_len = msg_hdr->frag_len;
+
+    if ((msg_hdr->frag_off + frag_len) > msg_hdr->msg_len ||
+        msg_hdr->msg_len > dtls1_max_handshake_message_len(s))
+        goto err;
+
+    if (frag_len == 0)
+        return DTLS1_HM_FRAGMENT_RETRY;
+
+    /* Try to find item in queue */
+    memset(seq64be, 0, sizeof(seq64be));
+    seq64be[6] = (unsigned char)(msg_hdr->seq >> 8);
+    seq64be[7] = (unsigned char)msg_hdr->seq;
+    item = pqueue_find(s->d1->buffered_messages, seq64be);
+
+    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 (frag->msg_header.msg_len != msg_hdr->msg_len) {
+            item = NULL;
+            frag = NULL;
+            goto err;
+        }
+    }
+
+    /*
+     * If message is already reassembled, this must be a retransmit and can
+     * be dropped. In this case item != NULL and so frag does not need to be
+     * freed.
+     */
+    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 ((unsigned long)i != frag_len)
+        i = -1;
+    if (i <= 0)
+        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) {
+        item = pitem_new(seq64be, frag);
+        if (item == NULL) {
+            i = -1;
+            goto err;
+        }
+
+        item = pqueue_insert(s->d1->buffered_messages, item);
+        /*
+         * pqueue_insert fails iff a duplicate item is inserted. However,
+         * |item| cannot be a duplicate. If it were, |pqueue_find|, above,
+         * would have returned it and control would never have reached this
+         * branch.
+         */
+        OPENSSL_assert(item != NULL);
+    }
+
+    return DTLS1_HM_FRAGMENT_RETRY;
+
+ err:
+    if (frag != NULL && item == NULL)
+        dtls1_hm_fragment_free(frag);
+    *ok = 0;
+    return i;
+}
 
 static int
-dtls1_process_out_of_seq_message(SSL *s, struct hm_header_st* msg_hdr, int *ok)
+dtls1_process_out_of_seq_message(SSL *s, const struct hm_header_st *msg_hdr,
+                                 int *ok)
 {
-       int i=-1;
-       hm_fragment *frag = NULL;
-       pitem *item = NULL;
-       unsigned char seq64be[8];
-       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 */
-       memset(seq64be,0,sizeof(seq64be));
-       seq64be[6] = (unsigned char) (msg_hdr->seq>>8);
-       seq64be[7] = (unsigned char) msg_hdr->seq;
-       item = pqueue_find(s->d1->buffered_messages, seq64be);
-       
-       /* 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;
-                       }
-               }
-
-       if (frag_len)
-               {
-               frag = dtls1_hm_fragment_new(frag_len);
-               if ( frag == NULL)
-                       goto err;
-
-               memcpy(&(frag->msg_header), msg_hdr, sizeof(*msg_hdr));
-
-               /* 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;
-
-               memset(seq64be,0,sizeof(seq64be));
-               seq64be[6] = (unsigned char)(msg_hdr->seq>>8);
-               seq64be[7] = (unsigned char)(msg_hdr->seq);
-
-               item = pitem_new(seq64be, frag);
-               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;
-       }
-
+    int i = -1;
+    hm_fragment *frag = NULL;
+    pitem *item = NULL;
+    unsigned char seq64be[8];
+    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 */
+    memset(seq64be, 0, sizeof(seq64be));
+    seq64be[6] = (unsigned char)(msg_hdr->seq >> 8);
+    seq64be[7] = (unsigned char)msg_hdr->seq;
+    item = pqueue_find(s->d1->buffered_messages, seq64be);
+
+    /*
+     * 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 != msg_hdr->msg_len)
+            return dtls1_reassemble_fragment(s, msg_hdr, ok);
+
+        if (frag_len > dtls1_max_handshake_message_len(s))
+            goto err;
+
+        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 ((unsigned long)i != frag_len)
+                i = -1;
+            if (i <= 0)
+                goto err;
+        }
+
+        item = pitem_new(seq64be, frag);
+        if (item == NULL)
+            goto err;
+
+        item = pqueue_insert(s->d1->buffered_messages, item);
+        /*
+         * pqueue_insert fails iff a duplicate item is inserted. However,
+         * |item| cannot be a duplicate. If it were, |pqueue_find|, above,
+         * would have returned it. Then, either |frag_len| !=
+         * |msg_hdr->msg_len| in which case |item| is set to NULL and it will
+         * have been processed with |dtls1_reassemble_fragment|, above, or
+         * the record will have been discarded.
+         */
+        OPENSSL_assert(item != NULL);
+    }
+
+    return DTLS1_HM_FRAGMENT_RETRY;
+
+ err:
+    if (frag != NULL && item == NULL)
+        dtls1_hm_fragment_free(frag);
+    *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 l, 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;
-               }
-       OPENSSL_assert(i == DTLS1_HM_HEADER_LENGTH);
-
-       /* 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 
-        */
-       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;
-
-       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 */
-       OPENSSL_assert(i == (int)frag_len);
-
-       *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,
-                       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
+{
+    unsigned char wire[DTLS1_HM_HEADER_LENGTH];
+    unsigned long len, frag_off, frag_len;
+    int i, al;
+    struct hm_header_st msg_hdr;
+
+ redo:
+    /* 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;
+            goto redo;
+        } 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);
+}
+
+/*-
+ * 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->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);
-               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);
-       }
+{
+    unsigned char *p;
 
-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 (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 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
+        if (s->version == DTLS1_BAD_VER) {
+            s->d1->next_handshake_write_seq++;
+            s2n(s->d1->handshake_write_seq, p);
+            s->init_num += 2;
+        }
 
-       return dtls1_handle_timeout(s);
-       }
+        s->init_off = 0;
 
-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;
-       }
+        dtls1_set_message_header_int(s, SSL3_MT_CCS, 0,
+                                     s->d1->handshake_write_seq, 0, 0);
 
-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;
-       }
+        /* buffer the message to handle re-xmits */
+        if(!dtls1_buffer_message(s, 1)) {
+            SSLerr(SSL_F_DTLS1_SEND_CHANGE_CIPHER_SPEC, ERR_R_INTERNAL_ERROR);
+            return -1;
+        }
 
-int
-dtls1_buffer_message(SSL *s, int is_ccs)
-       {
-       pitem *item;
-       hm_fragment *frag;
-       unsigned char seq64be[8];
-
-       /* 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 + 
-                              ((s->version==DTLS1_VERSION)?DTLS1_CCS_HEADER_LENGTH:3) == (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;
-       
-       memset(seq64be,0,sizeof(seq64be));
-       seq64be[6] = (unsigned char)(dtls1_get_queue_priority(frag->msg_header.seq,
-                                                                                                                 frag->msg_header.is_ccs)>>8);
-       seq64be[7] = (unsigned char)(dtls1_get_queue_priority(frag->msg_header.seq,
-                                                                                                                 frag->msg_header.is_ccs));
-
-       item = pitem_new(seq64be, frag);
-       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);
+        s->state = b;
+    }
+
+    /* SSL3_ST_CW_CHANGE_B */
+    return (dtls1_do_write(s, SSL3_RT_CHANGE_CIPHER_SPEC));
+}
+
+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;
+    }
+#ifndef OPENSSL_NO_HEARTBEATS
+    /* done, no need to send a retransmit */
+    if (!SSL_in_init(s) && !s->tlsext_hb_pending)
+#else
+    /* done, no need to send a retransmit */
+    if (!SSL_in_init(s))
 #endif
+    {
+        BIO_set_flags(SSL_get_rbio(s), BIO_FLAGS_READ);
+        return code;
+    }
 
-       pqueue_insert(s->d1->sent_messages, item);
-       return 1;
-       }
+    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;
+    unsigned char seq64be[8];
+
+    /*
+     * 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);
+    if (!frag)
+        return 0;
+
+    memcpy(frag->fragment, s->init_buf->data, s->init_num);
+
+    if (is_ccs) {
+        /* For DTLS1_BAD_VER the header length is non-standard */
+        OPENSSL_assert(s->d1->w_msg_hdr.msg_len +
+                       ((s->version==DTLS1_BAD_VER)?3: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;
+
+    memset(seq64be, 0, sizeof(seq64be));
+    seq64be[6] =
+        (unsigned
+         char)(dtls1_get_queue_priority(frag->msg_header.seq,
+                                        frag->msg_header.is_ccs) >> 8);
+    seq64be[7] =
+        (unsigned
+         char)(dtls1_get_queue_priority(frag->msg_header.seq,
+                                        frag->msg_header.is_ccs));
+
+    item = pitem_new(seq64be, frag);
+    if (item == NULL) {
+        dtls1_hm_fragment_free(frag);
+        return 0;
+    }
+
+    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;
-       unsigned char seq64be[8];
-       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 */
-       memset(seq64be,0,sizeof(seq64be));
-       seq64be[6] = (unsigned char)(seq>>8);
-       seq64be[7] = (unsigned char)seq;
-
-       item = pqueue_find(s->d1->sent_messages, seq64be);
-       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;
-       }
+                         int *found)
+{
+    int ret;
+    /* XDTLS: for now assuming that read/writes are blocking */
+    pitem *item;
+    hm_fragment *frag;
+    unsigned long header_length;
+    unsigned char seq64be[8];
+    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 */
+    memset(seq64be, 0, sizeof(seq64be));
+    seq64be[6] = (unsigned char)(seq >> 8);
+    seq64be[7] = (unsigned char)seq;
+
+    item = pqueue_find(s->d1->sent_messages, seq64be);
+    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)
-       {
-       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;
-       }
+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);
+    }
+}
+
+void 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);
+}
 
 /* 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;
-       }
+                             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);
+                         unsigned long frag_len)
+{
+    struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
 
-       s2n(msg_hdr->seq, p);
-       l2n3(msg_hdr->frag_off, p);
-       l2n3(msg_hdr->frag_len, p);
+    msg_hdr->frag_off = frag_off;
+    msg_hdr->frag_len = frag_len;
+}
 
-       return p;
-       }
+static unsigned char *dtls1_write_message_header(SSL *s, unsigned char *p)
+{
+    struct hm_header_st *msg_hdr = &s->d1->w_msg_hdr;
 
-static unsigned int 
-dtls1_min_mtu(void)
-       {
-       return (g_probable_mtu[(sizeof(g_probable_mtu) / 
-               sizeof(g_probable_mtu[0])) - 1]);
-       }
+    *p++ = msg_hdr->type;
+    l2n3(msg_hdr->msg_len, p);
 
-static unsigned int 
-dtls1_guess_mtu(unsigned int curr_mtu)
-       {
-       unsigned int i;
+    s2n(msg_hdr->seq, p);
+    l2n3(msg_hdr->frag_off, p);
+    l2n3(msg_hdr->frag_len, p);
 
-       if ( curr_mtu == 0 )
-               return g_probable_mtu[0] ;
+    return p;
+}
 
-       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];
+unsigned int dtls1_link_min_mtu(void)
+{
+    return (g_probable_mtu[(sizeof(g_probable_mtu) /
+                            sizeof(g_probable_mtu[0])) - 1]);
+}
 
-       return curr_mtu;
-       }
+unsigned int dtls1_min_mtu(SSL *s)
+{
+    return dtls1_link_min_mtu() - BIO_dgram_get_mtu_overhead(SSL_get_wbio(s));
+}
 
 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);
+{
+    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);
-       }
+    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));
+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++);
+}
 
-       ccs_hdr->type = *(data++);
-       }
+int dtls1_shutdown(SSL *s)
+{
+    int ret;
+#ifndef OPENSSL_NO_SCTP
+    if (BIO_dgram_is_sctp(SSL_get_wbio(s)) &&
+        !(s->shutdown & SSL_SENT_SHUTDOWN)) {
+        ret = BIO_dgram_sctp_wait_for_dry(SSL_get_wbio(s));
+        if (ret < 0)
+            return -1;
+
+        if (ret == 0)
+            BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 1,
+                     NULL);
+    }
+#endif
+    ret = ssl3_shutdown(s);
+#ifndef OPENSSL_NO_SCTP
+    BIO_ctrl(SSL_get_wbio(s), BIO_CTRL_DGRAM_SCTP_SAVE_SHUTDOWN, 0, NULL);
+#endif
+    return ret;
+}
+
+#ifndef OPENSSL_NO_HEARTBEATS
+int dtls1_process_heartbeat(SSL *s, unsigned char *p, unsigned int length)
+{
+    unsigned char *pl;
+    unsigned short hbtype;
+    unsigned int payload;
+    unsigned int padding = 16;  /* Use minimum padding */
+
+    if (s->msg_callback)
+        s->msg_callback(0, s->version, TLS1_RT_HEARTBEAT,
+                        p, length, s, s->msg_callback_arg);
+
+    /* Read type and payload length first */
+    if (1 + 2 + 16 > length)
+        return 0;               /* silently discard */
+    if (length > SSL3_RT_MAX_PLAIN_LENGTH)
+        return 0;               /* silently discard per RFC 6520 sec. 4 */
+
+    hbtype = *p++;
+    n2s(p, payload);
+    if (1 + 2 + payload + 16 > length)
+        return 0;               /* silently discard per RFC 6520 sec. 4 */
+    pl = p;
+
+    if (hbtype == TLS1_HB_REQUEST) {
+        unsigned char *buffer, *bp;
+        unsigned int write_length = 1 /* heartbeat type */  +
+            2 /* heartbeat length */  +
+            payload + padding;
+        int r;
+
+        if (write_length > SSL3_RT_MAX_PLAIN_LENGTH)
+            return 0;
+
+        /*
+         * Allocate memory for the response, size is 1 byte message type,
+         * plus 2 bytes payload length, plus payload, plus padding
+         */
+        buffer = OPENSSL_malloc(write_length);
+        if (buffer == NULL)
+            return -1;
+        bp = buffer;
+
+        /* Enter response type, length and copy payload */
+        *bp++ = TLS1_HB_RESPONSE;
+        s2n(payload, bp);
+        memcpy(bp, pl, payload);
+        bp += payload;
+        /* Random padding */
+        if (RAND_bytes(bp, padding) <= 0) {
+            OPENSSL_free(buffer);
+            return -1;
+        }
+
+        r = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buffer, write_length);
+
+        if (r >= 0 && s->msg_callback)
+            s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
+                            buffer, write_length, s, s->msg_callback_arg);
+
+        OPENSSL_free(buffer);
+
+        if (r < 0)
+            return r;
+    } else if (hbtype == TLS1_HB_RESPONSE) {
+        unsigned int seq;
+
+        /*
+         * We only send sequence numbers (2 bytes unsigned int), and 16
+         * random bytes, so we just try to read the sequence number
+         */
+        n2s(pl, seq);
+
+        if (payload == 18 && seq == s->tlsext_hb_seq) {
+            dtls1_stop_timer(s);
+            s->tlsext_hb_seq++;
+            s->tlsext_hb_pending = 0;
+        }
+    }
+
+    return 0;
+}
+
+int dtls1_heartbeat(SSL *s)
+{
+    unsigned char *buf, *p;
+    int ret = -1;
+    unsigned int payload = 18;  /* Sequence number + random bytes */
+    unsigned int padding = 16;  /* Use minimum padding */
+
+    /* Only send if peer supports and accepts HB requests... */
+    if (!(s->tlsext_heartbeat & SSL_TLSEXT_HB_ENABLED) ||
+        s->tlsext_heartbeat & SSL_TLSEXT_HB_DONT_SEND_REQUESTS) {
+        SSLerr(SSL_F_DTLS1_HEARTBEAT, SSL_R_TLS_HEARTBEAT_PEER_DOESNT_ACCEPT);
+        return -1;
+    }
+
+    /* ...and there is none in flight yet... */
+    if (s->tlsext_hb_pending) {
+        SSLerr(SSL_F_DTLS1_HEARTBEAT, SSL_R_TLS_HEARTBEAT_PENDING);
+        return -1;
+    }
+
+    /* ...and no handshake in progress. */
+    if (SSL_in_init(s) || s->in_handshake) {
+        SSLerr(SSL_F_DTLS1_HEARTBEAT, SSL_R_UNEXPECTED_MESSAGE);
+        return -1;
+    }
+
+    /*
+     * Check if padding is too long, payload and padding must not exceed 2^14
+     * - 3 = 16381 bytes in total.
+     */
+    OPENSSL_assert(payload + padding <= 16381);
+
+    /*-
+     * Create HeartBeat message, we just use a sequence number
+     * as payload to distuingish different messages and add
+     * some random stuff.
+     *  - Message Type, 1 byte
+     *  - Payload Length, 2 bytes (unsigned int)
+     *  - Payload, the sequence number (2 bytes uint)
+     *  - Payload, random bytes (16 bytes uint)
+     *  - Padding
+     */
+    buf = OPENSSL_malloc(1 + 2 + payload + padding);
+    if (buf == NULL) {
+        SSLerr(SSL_F_DTLS1_HEARTBEAT, ERR_R_MALLOC_FAILURE);
+        return -1;
+    }
+    p = buf;
+    /* Message Type */
+    *p++ = TLS1_HB_REQUEST;
+    /* Payload length (18 bytes here) */
+    s2n(payload, p);
+    /* Sequence number */
+    s2n(s->tlsext_hb_seq, p);
+    /* 16 random bytes */
+    if (RAND_bytes(p, 16) <= 0) {
+        SSLerr(SSL_F_DTLS1_HEARTBEAT, ERR_R_INTERNAL_ERROR);
+        goto err;
+    }
+    p += 16;
+    /* Random padding */
+    if (RAND_bytes(p, padding) <= 0) {
+        SSLerr(SSL_F_DTLS1_HEARTBEAT, ERR_R_INTERNAL_ERROR);
+        goto err;
+    }
+
+    ret = dtls1_write_bytes(s, TLS1_RT_HEARTBEAT, buf, 3 + payload + padding);
+    if (ret >= 0) {
+        if (s->msg_callback)
+            s->msg_callback(1, s->version, TLS1_RT_HEARTBEAT,
+                            buf, 3 + payload + padding,
+                            s, s->msg_callback_arg);
+
+        dtls1_start_timer(s);
+        s->tlsext_hb_pending = 1;
+    }
+
+ err:
+    OPENSSL_free(buf);
+
+    return ret;
+}
+#endif