You are viewing a plain text version of this content. The canonical link for it is here.
Posted to commits@mynewt.apache.org by GitBox <gi...@apache.org> on 2018/09/25 10:01:01 UTC

[GitHub] utzig closed pull request #1427: Update mbedtls to version 2.13.0

utzig closed pull request #1427: Update mbedtls to version 2.13.0
URL: https://github.com/apache/mynewt-core/pull/1427
 
 
   

This is a PR merged from a forked repository.
As GitHub hides the original diff on merge, it is displayed below for
the sake of provenance:

As this is a foreign pull request (from a fork), the diff is supplied
below (as it won't show otherwise due to GitHub magic):

diff --git a/crypto/mbedtls/include/mbedtls/aes.h b/crypto/mbedtls/include/mbedtls/aes.h
index f6603d5962..4c8dab3151 100644
--- a/crypto/mbedtls/include/mbedtls/aes.h
+++ b/crypto/mbedtls/include/mbedtls/aes.h
@@ -79,7 +79,7 @@ extern "C" {
 /**
  * \brief The AES context-type definition.
  */
-typedef struct
+typedef struct mbedtls_aes_context
 {
     int nr;                     /*!< The number of rounds. */
     uint32_t *rk;               /*!< AES round keys. */
@@ -98,7 +98,7 @@ mbedtls_aes_context;
 /**
  * \brief The AES XTS context-type definition.
  */
-typedef struct
+typedef struct mbedtls_aes_xts_context
 {
     mbedtls_aes_context crypt; /*!< The AES context to use for AES block
                                         encryption or decryption. */
diff --git a/crypto/mbedtls/include/mbedtls/arc4.h b/crypto/mbedtls/include/mbedtls/arc4.h
index f11fc5be0a..83a7461f3f 100644
--- a/crypto/mbedtls/include/mbedtls/arc4.h
+++ b/crypto/mbedtls/include/mbedtls/arc4.h
@@ -53,7 +53,7 @@ extern "C" {
  *            security risk. We recommend considering stronger ciphers instead.
  *
  */
-typedef struct
+typedef struct mbedtls_arc4_context
 {
     int x;                      /*!< permutation index */
     int y;                      /*!< permutation index */
diff --git a/crypto/mbedtls/include/mbedtls/aria.h b/crypto/mbedtls/include/mbedtls/aria.h
index bae0621b23..4a79c13872 100644
--- a/crypto/mbedtls/include/mbedtls/aria.h
+++ b/crypto/mbedtls/include/mbedtls/aria.h
@@ -62,7 +62,7 @@ extern "C" {
 /**
  * \brief The ARIA context-type definition.
  */
-typedef struct
+typedef struct mbedtls_aria_context
 {
     unsigned char nr;           /*!< The number of rounds (12, 14 or 16) */
     /*! The ARIA round keys. */
diff --git a/crypto/mbedtls/include/mbedtls/bignum.h b/crypto/mbedtls/include/mbedtls/bignum.h
index 31383b1eb5..732ecbef1c 100644
--- a/crypto/mbedtls/include/mbedtls/bignum.h
+++ b/crypto/mbedtls/include/mbedtls/bignum.h
@@ -177,7 +177,7 @@ extern "C" {
 /**
  * \brief          MPI structure
  */
-typedef struct
+typedef struct mbedtls_mpi
 {
     int s;              /*!<  integer sign      */
     size_t n;           /*!<  total # of limbs  */
diff --git a/crypto/mbedtls/include/mbedtls/blowfish.h b/crypto/mbedtls/include/mbedtls/blowfish.h
index 985faa43f0..eea6882f75 100644
--- a/crypto/mbedtls/include/mbedtls/blowfish.h
+++ b/crypto/mbedtls/include/mbedtls/blowfish.h
@@ -55,7 +55,7 @@ extern "C" {
 /**
  * \brief          Blowfish context structure
  */
-typedef struct
+typedef struct mbedtls_blowfish_context
 {
     uint32_t P[MBEDTLS_BLOWFISH_ROUNDS + 2];    /*!<  Blowfish round keys    */
     uint32_t S[4][256];                 /*!<  key dependent S-boxes  */
diff --git a/crypto/mbedtls/include/mbedtls/camellia.h b/crypto/mbedtls/include/mbedtls/camellia.h
index 7e4721af78..fa1e05ee7f 100644
--- a/crypto/mbedtls/include/mbedtls/camellia.h
+++ b/crypto/mbedtls/include/mbedtls/camellia.h
@@ -51,7 +51,7 @@ extern "C" {
 /**
  * \brief          CAMELLIA context structure
  */
-typedef struct
+typedef struct mbedtls_camellia_context
 {
     int nr;                     /*!<  number of rounds  */
     uint32_t rk[68];            /*!<  CAMELLIA round keys    */
diff --git a/crypto/mbedtls/include/mbedtls/ccm.h b/crypto/mbedtls/include/mbedtls/ccm.h
index 5d727e7cca..e1dc124b89 100644
--- a/crypto/mbedtls/include/mbedtls/ccm.h
+++ b/crypto/mbedtls/include/mbedtls/ccm.h
@@ -68,7 +68,8 @@ extern "C" {
  * \brief    The CCM context-type definition. The CCM context is passed
  *           to the APIs called.
  */
-typedef struct {
+typedef struct mbedtls_ccm_context
+{
     mbedtls_cipher_context_t cipher_ctx;    /*!< The cipher context used. */
 }
 mbedtls_ccm_context;
diff --git a/crypto/mbedtls/include/mbedtls/chacha20.h b/crypto/mbedtls/include/mbedtls/chacha20.h
index 47bd7d38b9..cfea40a574 100644
--- a/crypto/mbedtls/include/mbedtls/chacha20.h
+++ b/crypto/mbedtls/include/mbedtls/chacha20.h
@@ -52,7 +52,7 @@ extern "C" {
 
 #if !defined(MBEDTLS_CHACHA20_ALT)
 
-typedef struct
+typedef struct mbedtls_chacha20_context
 {
     uint32_t state[16];          /*! The state (before round operations). */
     uint8_t  keystream8[64];     /*! Leftover keystream bytes. */
diff --git a/crypto/mbedtls/include/mbedtls/chachapoly.h b/crypto/mbedtls/include/mbedtls/chachapoly.h
index 42b2b230c5..7de6f4e8c6 100644
--- a/crypto/mbedtls/include/mbedtls/chachapoly.h
+++ b/crypto/mbedtls/include/mbedtls/chachapoly.h
@@ -60,7 +60,7 @@ mbedtls_chachapoly_mode_t;
 
 #include "chacha20.h"
 
-typedef struct
+typedef struct mbedtls_chachapoly_context
 {
     mbedtls_chacha20_context chacha20_ctx;  /**< The ChaCha20 context. */
     mbedtls_poly1305_context poly1305_ctx;  /**< The Poly1305 context. */
diff --git a/crypto/mbedtls/include/mbedtls/cipher.h b/crypto/mbedtls/include/mbedtls/cipher.h
index ea0ce983f1..dfb1541103 100644
--- a/crypto/mbedtls/include/mbedtls/cipher.h
+++ b/crypto/mbedtls/include/mbedtls/cipher.h
@@ -45,7 +45,8 @@
 #define MBEDTLS_CIPHER_MODE_WITH_PADDING
 #endif
 
-#if defined(MBEDTLS_ARC4_C) || defined(MBEDTLS_CIPHER_NULL_CIPHER)
+#if defined(MBEDTLS_ARC4_C) || defined(MBEDTLS_CIPHER_NULL_CIPHER) || \
+    defined(MBEDTLS_CHACHA20_C)
 #define MBEDTLS_CIPHER_MODE_STREAM
 #endif
 
@@ -235,7 +236,8 @@ typedef struct mbedtls_cmac_context_t mbedtls_cmac_context_t;
  * Cipher information. Allows calling cipher functions
  * in a generic way.
  */
-typedef struct {
+typedef struct mbedtls_cipher_info_t
+{
     /** Full cipher identifier. For example,
      * MBEDTLS_CIPHER_AES_256_CBC.
      */
@@ -276,7 +278,8 @@ typedef struct {
 /**
  * Generic cipher context.
  */
-typedef struct {
+typedef struct mbedtls_cipher_context_t
+{
     /** Information about the associated cipher. */
     const mbedtls_cipher_info_t *cipher_info;
 
diff --git a/crypto/mbedtls/include/mbedtls/config.h b/crypto/mbedtls/include/mbedtls/config.h
index e485811c37..5bb47745bb 100644
--- a/crypto/mbedtls/include/mbedtls/config.h
+++ b/crypto/mbedtls/include/mbedtls/config.h
@@ -3010,6 +3010,23 @@
  */
 //#define MBEDTLS_SSL_OUT_CONTENT_LEN             16384
 
+/** \def MBEDTLS_SSL_DTLS_MAX_BUFFERING
+ *
+ * Maximum number of heap-allocated bytes for the purpose of
+ * DTLS handshake message reassembly and future message buffering.
+ *
+ * This should be at least 9/8 * MBEDTLSSL_IN_CONTENT_LEN
+ * to account for a reassembled handshake message of maximum size,
+ * together with its reassembly bitmap.
+ *
+ * A value of 2 * MBEDTLS_SSL_IN_CONTENT_LEN (32768 by default)
+ * should be sufficient for all practical situations as it allows
+ * to reassembly a large handshake message (such as a certificate)
+ * while buffering multiple smaller handshake messages.
+ *
+ */
+//#define MBEDTLS_SSL_DTLS_MAX_BUFFERING             32768
+
 //#define MBEDTLS_SSL_DEFAULT_TICKET_LIFETIME     86400 /**< Lifetime of session tickets (if enabled) */
 //#define MBEDTLS_PSK_MAX_LEN               32 /**< Max size of TLS pre-shared keys, in bytes (default 256 bits) */
 //#define MBEDTLS_SSL_COOKIE_TIMEOUT        60 /**< Default expiration delay of DTLS cookies, in seconds if HAVE_TIME, or in number of cookies issued */
diff --git a/crypto/mbedtls/include/mbedtls/ctr_drbg.h b/crypto/mbedtls/include/mbedtls/ctr_drbg.h
index 1db1ba4c44..69d06aeb3b 100644
--- a/crypto/mbedtls/include/mbedtls/ctr_drbg.h
+++ b/crypto/mbedtls/include/mbedtls/ctr_drbg.h
@@ -108,7 +108,7 @@ extern "C" {
 /**
  * \brief          The CTR_DRBG context structure.
  */
-typedef struct
+typedef struct mbedtls_ctr_drbg_context
 {
     unsigned char counter[16];  /*!< The counter (V). */
     int reseed_counter;         /*!< The reseed counter. */
diff --git a/crypto/mbedtls/include/mbedtls/des.h b/crypto/mbedtls/include/mbedtls/des.h
index 6eb7d03bae..91d16b6fb4 100644
--- a/crypto/mbedtls/include/mbedtls/des.h
+++ b/crypto/mbedtls/include/mbedtls/des.h
@@ -61,7 +61,7 @@ extern "C" {
  *                 security risk. We recommend considering stronger ciphers
  *                 instead.
  */
-typedef struct
+typedef struct mbedtls_des_context
 {
     uint32_t sk[32];            /*!<  DES subkeys       */
 }
@@ -70,7 +70,7 @@ mbedtls_des_context;
 /**
  * \brief          Triple-DES context structure
  */
-typedef struct
+typedef struct mbedtls_des3_context
 {
     uint32_t sk[96];            /*!<  3DES subkeys      */
 }
diff --git a/crypto/mbedtls/include/mbedtls/dhm.h b/crypto/mbedtls/include/mbedtls/dhm.h
index 75317a8e6d..3e1178940a 100644
--- a/crypto/mbedtls/include/mbedtls/dhm.h
+++ b/crypto/mbedtls/include/mbedtls/dhm.h
@@ -96,7 +96,7 @@ extern "C" {
 /**
  * \brief          The DHM context structure.
  */
-typedef struct
+typedef struct mbedtls_dhm_context
 {
     size_t len;         /*!<  The size of \p P in Bytes. */
     mbedtls_mpi P;      /*!<  The prime modulus. */
diff --git a/crypto/mbedtls/include/mbedtls/ecdh.h b/crypto/mbedtls/include/mbedtls/ecdh.h
index 5fdf55a88a..95f39805c6 100644
--- a/crypto/mbedtls/include/mbedtls/ecdh.h
+++ b/crypto/mbedtls/include/mbedtls/ecdh.h
@@ -52,7 +52,7 @@ typedef enum
 /**
  * \brief           The ECDH context structure.
  */
-typedef struct
+typedef struct mbedtls_ecdh_context
 {
     mbedtls_ecp_group grp;   /*!< The elliptic curve used. */
     mbedtls_mpi d;           /*!< The private key. */
diff --git a/crypto/mbedtls/include/mbedtls/ecjpake.h b/crypto/mbedtls/include/mbedtls/ecjpake.h
index cc2b316f5e..59d12f080f 100644
--- a/crypto/mbedtls/include/mbedtls/ecjpake.h
+++ b/crypto/mbedtls/include/mbedtls/ecjpake.h
@@ -68,7 +68,7 @@ typedef enum {
  * convetion from the Thread v1.0 spec. Correspondance is indicated in the
  * description as a pair C: client name, S: server name
  */
-typedef struct
+typedef struct mbedtls_ecjpake_context
 {
     const mbedtls_md_info_t *md_info;   /**< Hash to use                    */
     mbedtls_ecp_group grp;              /**< Elliptic curve                 */
diff --git a/crypto/mbedtls/include/mbedtls/ecp.h b/crypto/mbedtls/include/mbedtls/ecp.h
index 3a407986dd..ed1b9d7368 100644
--- a/crypto/mbedtls/include/mbedtls/ecp.h
+++ b/crypto/mbedtls/include/mbedtls/ecp.h
@@ -92,7 +92,7 @@ typedef enum
 /**
  * Curve information, for use by other modules.
  */
-typedef struct
+typedef struct mbedtls_ecp_curve_info
 {
     mbedtls_ecp_group_id grp_id;    /*!< An internal identifier. */
     uint16_t tls_id;                /*!< The TLS NamedCurve identifier. */
@@ -111,7 +111,7 @@ typedef struct
  *                  Otherwise, \p X and \p Y are its standard (affine)
  *                  coordinates.
  */
-typedef struct
+typedef struct mbedtls_ecp_point
 {
     mbedtls_mpi X;          /*!< The X coordinate of the ECP point. */
     mbedtls_mpi Y;          /*!< The Y coordinate of the ECP point. */
@@ -156,7 +156,7 @@ mbedtls_ecp_point;
  * reduction. It must return 0 on success and non-zero on failure.
  *
  */
-typedef struct
+typedef struct mbedtls_ecp_group
 {
     mbedtls_ecp_group_id id;    /*!< An internal group identifier. */
     mbedtls_mpi P;              /*!< The prime modulus of the base field. */
@@ -251,7 +251,7 @@ mbedtls_ecp_group;
  * \note    Members are deliberately in the same order as in the
  *          ::mbedtls_ecdsa_context structure.
  */
-typedef struct
+typedef struct mbedtls_ecp_keypair
 {
     mbedtls_ecp_group grp;      /*!<  Elliptic curve and base point     */
     mbedtls_mpi d;              /*!<  our secret value                  */
diff --git a/crypto/mbedtls/include/mbedtls/entropy.h b/crypto/mbedtls/include/mbedtls/entropy.h
index a5cb05a584..ca06dc3c58 100644
--- a/crypto/mbedtls/include/mbedtls/entropy.h
+++ b/crypto/mbedtls/include/mbedtls/entropy.h
@@ -107,7 +107,7 @@ typedef int (*mbedtls_entropy_f_source_ptr)(void *data, unsigned char *output, s
 /**
  * \brief           Entropy source state
  */
-typedef struct
+typedef struct mbedtls_entropy_source_state
 {
     mbedtls_entropy_f_source_ptr    f_source;   /**< The entropy source callback */
     void *          p_source;   /**< The callback data pointer */
@@ -120,7 +120,7 @@ mbedtls_entropy_source_state;
 /**
  * \brief           Entropy context structure
  */
-typedef struct
+typedef struct mbedtls_entropy_context
 {
     int accumulator_started;
 #if defined(MBEDTLS_ENTROPY_SHA512_ACCUMULATOR)
diff --git a/crypto/mbedtls/include/mbedtls/gcm.h b/crypto/mbedtls/include/mbedtls/gcm.h
index 87535ab957..d2098eb9f9 100644
--- a/crypto/mbedtls/include/mbedtls/gcm.h
+++ b/crypto/mbedtls/include/mbedtls/gcm.h
@@ -53,7 +53,8 @@ extern "C" {
 /**
  * \brief          The GCM context structure.
  */
-typedef struct {
+typedef struct mbedtls_gcm_context
+{
     mbedtls_cipher_context_t cipher_ctx;  /*!< The cipher context used. */
     uint64_t HL[16];                      /*!< Precalculated HTable low. */
     uint64_t HH[16];                      /*!< Precalculated HTable high. */
diff --git a/crypto/mbedtls/include/mbedtls/havege.h b/crypto/mbedtls/include/mbedtls/havege.h
index d4cb3ed38d..57e8c40943 100644
--- a/crypto/mbedtls/include/mbedtls/havege.h
+++ b/crypto/mbedtls/include/mbedtls/havege.h
@@ -35,7 +35,7 @@ extern "C" {
 /**
  * \brief          HAVEGE state structure
  */
-typedef struct
+typedef struct mbedtls_havege_state
 {
     int PT1, PT2, offset[2];
     int pool[MBEDTLS_HAVEGE_COLLECT_SIZE];
diff --git a/crypto/mbedtls/include/mbedtls/hkdf.h b/crypto/mbedtls/include/mbedtls/hkdf.h
index 626101e83a..1274491bec 100644
--- a/crypto/mbedtls/include/mbedtls/hkdf.h
+++ b/crypto/mbedtls/include/mbedtls/hkdf.h
@@ -73,6 +73,11 @@ int mbedtls_hkdf( const mbedtls_md_info_t *md, const unsigned char *salt,
  *  \brief  Take the input keying material \p ikm and extract from it a
  *          fixed-length pseudorandom key \p prk.
  *
+ *  \warning    This function should only be used if the security of it has been
+ *              studied and established in that particular context (eg. TLS 1.3
+ *              key schedule). For standard HKDF security guarantees use
+ *              \c mbedtls_hkdf instead.
+ *
  *  \param       md        A hash function; md.size denotes the length of the
  *                         hash function output in bytes.
  *  \param       salt      An optional salt value (a non-secret random value);
@@ -97,10 +102,15 @@ int mbedtls_hkdf_extract( const mbedtls_md_info_t *md,
  *  \brief  Expand the supplied \p prk into several additional pseudorandom
  *          keys, which is the output of the HKDF.
  *
+ *  \warning    This function should only be used if the security of it has been
+ *              studied and established in that particular context (eg. TLS 1.3
+ *              key schedule). For standard HKDF security guarantees use
+ *              \c mbedtls_hkdf instead.
+ *
  *  \param  md        A hash function; md.size denotes the length of the hash
  *                    function output in bytes.
- *  \param  prk       A pseudorandom key of at least md.size bytes. \p prk is usually,
- *                    the output from the HKDF extract step.
+ *  \param  prk       A pseudorandom key of at least md.size bytes. \p prk is
+ *                    usually the output from the HKDF extract step.
  *  \param  prk_len   The length in bytes of \p prk.
  *  \param  info      An optional context and application specific information
  *                    string. This can be a zero-length string.
diff --git a/crypto/mbedtls/include/mbedtls/hmac_drbg.h b/crypto/mbedtls/include/mbedtls/hmac_drbg.h
index 65c01246e8..16b4a750a8 100644
--- a/crypto/mbedtls/include/mbedtls/hmac_drbg.h
+++ b/crypto/mbedtls/include/mbedtls/hmac_drbg.h
@@ -74,7 +74,7 @@ extern "C" {
 /**
  * HMAC_DRBG context.
  */
-typedef struct
+typedef struct mbedtls_hmac_drbg_context
 {
     /* Working state: the key K is not stored explicitely,
      * but is implied by the HMAC context */
diff --git a/crypto/mbedtls/include/mbedtls/md.h b/crypto/mbedtls/include/mbedtls/md.h
index 6b6f5c53dd..bf29524983 100644
--- a/crypto/mbedtls/include/mbedtls/md.h
+++ b/crypto/mbedtls/include/mbedtls/md.h
@@ -80,7 +80,8 @@ typedef struct mbedtls_md_info_t mbedtls_md_info_t;
 /**
  * The generic message-digest context.
  */
-typedef struct {
+typedef struct mbedtls_md_context_t
+{
     /** Information about the associated message digest. */
     const mbedtls_md_info_t *md_info;
 
diff --git a/crypto/mbedtls/include/mbedtls/md2.h b/crypto/mbedtls/include/mbedtls/md2.h
index 08e75b247b..a46bddb74b 100644
--- a/crypto/mbedtls/include/mbedtls/md2.h
+++ b/crypto/mbedtls/include/mbedtls/md2.h
@@ -55,7 +55,7 @@ extern "C" {
  *                 stronger message digests instead.
  *
  */
-typedef struct
+typedef struct mbedtls_md2_context
 {
     unsigned char cksum[16];    /*!< checksum of the data block */
     unsigned char state[48];    /*!< intermediate digest state  */
diff --git a/crypto/mbedtls/include/mbedtls/md4.h b/crypto/mbedtls/include/mbedtls/md4.h
index 8ee4e5cabf..1672e9074e 100644
--- a/crypto/mbedtls/include/mbedtls/md4.h
+++ b/crypto/mbedtls/include/mbedtls/md4.h
@@ -56,7 +56,7 @@ extern "C" {
  *                 stronger message digests instead.
  *
  */
-typedef struct
+typedef struct mbedtls_md4_context
 {
     uint32_t total[2];          /*!< number of bytes processed  */
     uint32_t state[4];          /*!< intermediate digest state  */
diff --git a/crypto/mbedtls/include/mbedtls/md5.h b/crypto/mbedtls/include/mbedtls/md5.h
index 43ead4b747..4c9509010b 100644
--- a/crypto/mbedtls/include/mbedtls/md5.h
+++ b/crypto/mbedtls/include/mbedtls/md5.h
@@ -55,7 +55,7 @@ extern "C" {
  *                 stronger message digests instead.
  *
  */
-typedef struct
+typedef struct mbedtls_md5_context
 {
     uint32_t total[2];          /*!< number of bytes processed  */
     uint32_t state[4];          /*!< intermediate digest state  */
diff --git a/crypto/mbedtls/include/mbedtls/net_sockets.h b/crypto/mbedtls/include/mbedtls/net_sockets.h
index 9f07eeb4d3..4c7ef00fe6 100644
--- a/crypto/mbedtls/include/mbedtls/net_sockets.h
+++ b/crypto/mbedtls/include/mbedtls/net_sockets.h
@@ -84,7 +84,7 @@ extern "C" {
  * (eg two file descriptors for combined IPv4 + IPv6 support, or additional
  * structures for hand-made UDP demultiplexing).
  */
-typedef struct
+typedef struct mbedtls_net_context
 {
     int fd;             /**< The underlying file descriptor                 */
 }
diff --git a/crypto/mbedtls/include/mbedtls/oid.h b/crypto/mbedtls/include/mbedtls/oid.h
index f82554844c..6fbd018aaa 100644
--- a/crypto/mbedtls/include/mbedtls/oid.h
+++ b/crypto/mbedtls/include/mbedtls/oid.h
@@ -403,7 +403,8 @@ extern "C" {
 /**
  * \brief Base OID descriptor structure
  */
-typedef struct {
+typedef struct mbedtls_oid_descriptor_t
+{
     const char *asn1;               /*!< OID ASN.1 representation       */
     size_t asn1_len;                /*!< length of asn1                 */
     const char *name;               /*!< official name (e.g. from RFC)  */
diff --git a/crypto/mbedtls/include/mbedtls/pem.h b/crypto/mbedtls/include/mbedtls/pem.h
index 2cf4c0a709..fa82f7bdbd 100644
--- a/crypto/mbedtls/include/mbedtls/pem.h
+++ b/crypto/mbedtls/include/mbedtls/pem.h
@@ -51,7 +51,7 @@ extern "C" {
 /**
  * \brief       PEM context structure
  */
-typedef struct
+typedef struct mbedtls_pem_context
 {
     unsigned char *buf;     /*!< buffer for decoded data             */
     size_t buflen;          /*!< length of the buffer                */
diff --git a/crypto/mbedtls/include/mbedtls/pk.h b/crypto/mbedtls/include/mbedtls/pk.h
index ee06b2fd20..db54c6a6ef 100644
--- a/crypto/mbedtls/include/mbedtls/pk.h
+++ b/crypto/mbedtls/include/mbedtls/pk.h
@@ -87,7 +87,7 @@ typedef enum {
  * \brief           Options for RSASSA-PSS signature verification.
  *                  See \c mbedtls_rsa_rsassa_pss_verify_ext()
  */
-typedef struct
+typedef struct mbedtls_pk_rsassa_pss_options
 {
     mbedtls_md_type_t mgf1_hash_id;
     int expected_salt_len;
@@ -107,7 +107,7 @@ typedef enum
 /**
  * \brief           Item to send to the debug module
  */
-typedef struct
+typedef struct mbedtls_pk_debug_item
 {
     mbedtls_pk_debug_type type;
     const char *name;
@@ -125,7 +125,7 @@ typedef struct mbedtls_pk_info_t mbedtls_pk_info_t;
 /**
  * \brief           Public key container
  */
-typedef struct
+typedef struct mbedtls_pk_context
 {
     const mbedtls_pk_info_t *   pk_info; /**< Public key informations        */
     void *                      pk_ctx;  /**< Underlying public key context  */
diff --git a/crypto/mbedtls/include/mbedtls/pkcs11.h b/crypto/mbedtls/include/mbedtls/pkcs11.h
index bf65c55a79..02427ddc1e 100644
--- a/crypto/mbedtls/include/mbedtls/pkcs11.h
+++ b/crypto/mbedtls/include/mbedtls/pkcs11.h
@@ -50,7 +50,8 @@ extern "C" {
 /**
  * Context for PKCS #11 private keys.
  */
-typedef struct {
+typedef struct mbedtls_pkcs11_context
+{
         pkcs11h_certificate_t pkcs11h_cert;
         int len;
 } mbedtls_pkcs11_context;
diff --git a/crypto/mbedtls/include/mbedtls/platform.h b/crypto/mbedtls/include/mbedtls/platform.h
index 9d9c5293eb..e299c16caa 100644
--- a/crypto/mbedtls/include/mbedtls/platform.h
+++ b/crypto/mbedtls/include/mbedtls/platform.h
@@ -40,7 +40,7 @@
 #endif
 
 #if defined(MBEDTLS_HAVE_TIME)
-#include "mbedtls/platform_time.h"
+#include "mbedlts/platform_time.h"
 #endif
 
 #ifdef __cplusplus
@@ -315,7 +315,8 @@ int mbedtls_platform_set_nv_seed(
  * \note    This structure may be used to assist platform-specific
  *          setup or teardown operations.
  */
-typedef struct {
+typedef struct mbedtls_platform_context
+{
     char dummy; /**< A placeholder member, as empty structs are not portable. */
 }
 mbedtls_platform_context;
diff --git a/crypto/mbedtls/include/mbedtls/poly1305.h b/crypto/mbedtls/include/mbedtls/poly1305.h
index 54b50abc25..c490cdf2bd 100644
--- a/crypto/mbedtls/include/mbedtls/poly1305.h
+++ b/crypto/mbedtls/include/mbedtls/poly1305.h
@@ -52,7 +52,7 @@ extern "C" {
 
 #if !defined(MBEDTLS_POLY1305_ALT)
 
-typedef struct
+typedef struct mbedtls_poly1305_context
 {
     uint32_t r[4];      /** The value for 'r' (low 128 bits of the key). */
     uint32_t s[4];      /** The value for 's' (high 128 bits of the key). */
diff --git a/crypto/mbedtls/include/mbedtls/ripemd160.h b/crypto/mbedtls/include/mbedtls/ripemd160.h
index a0dac0c360..0c8e568b9e 100644
--- a/crypto/mbedtls/include/mbedtls/ripemd160.h
+++ b/crypto/mbedtls/include/mbedtls/ripemd160.h
@@ -46,7 +46,7 @@ extern "C" {
 /**
  * \brief          RIPEMD-160 context structure
  */
-typedef struct
+typedef struct mbedtls_ripemd160_context
 {
     uint32_t total[2];          /*!< number of bytes processed  */
     uint32_t state[5];          /*!< intermediate digest state  */
diff --git a/crypto/mbedtls/include/mbedtls/rsa.h b/crypto/mbedtls/include/mbedtls/rsa.h
index 19eb2ee74c..6eea5af2f0 100644
--- a/crypto/mbedtls/include/mbedtls/rsa.h
+++ b/crypto/mbedtls/include/mbedtls/rsa.h
@@ -92,7 +92,7 @@ extern "C" {
  *          is deprecated. All manipulation should instead be done through
  *          the public interface functions.
  */
-typedef struct
+typedef struct mbedtls_rsa_context
 {
     int ver;                    /*!<  Always 0.*/
     size_t len;                 /*!<  The size of \p N in Bytes. */
diff --git a/crypto/mbedtls/include/mbedtls/sha1.h b/crypto/mbedtls/include/mbedtls/sha1.h
index 65a124c94b..7a19da0a48 100644
--- a/crypto/mbedtls/include/mbedtls/sha1.h
+++ b/crypto/mbedtls/include/mbedtls/sha1.h
@@ -58,7 +58,7 @@ extern "C" {
  *                 stronger message digests instead.
  *
  */
-typedef struct
+typedef struct mbedtls_sha1_context
 {
     uint32_t total[2];          /*!< The number of Bytes processed.  */
     uint32_t state[5];          /*!< The intermediate digest state.  */
diff --git a/crypto/mbedtls/include/mbedtls/sha256.h b/crypto/mbedtls/include/mbedtls/sha256.h
index adf31a82ed..33aff28314 100644
--- a/crypto/mbedtls/include/mbedtls/sha256.h
+++ b/crypto/mbedtls/include/mbedtls/sha256.h
@@ -53,7 +53,7 @@ extern "C" {
  *                 checksum calculations. The choice between these two is
  *                 made in the call to mbedtls_sha256_starts_ret().
  */
-typedef struct
+typedef struct mbedtls_sha256_context
 {
     uint32_t total[2];          /*!< The number of Bytes processed.  */
     uint32_t state[8];          /*!< The intermediate digest state.  */
diff --git a/crypto/mbedtls/include/mbedtls/sha512.h b/crypto/mbedtls/include/mbedtls/sha512.h
index 5bb83f43bd..0145890424 100644
--- a/crypto/mbedtls/include/mbedtls/sha512.h
+++ b/crypto/mbedtls/include/mbedtls/sha512.h
@@ -52,7 +52,7 @@ extern "C" {
  *                 checksum calculations. The choice between these two is
  *                 made in the call to mbedtls_sha512_starts_ret().
  */
-typedef struct
+typedef struct mbedtls_sha512_context
 {
     uint64_t total[2];          /*!< The number of Bytes processed. */
     uint64_t state[8];          /*!< The intermediate digest state. */
diff --git a/crypto/mbedtls/include/mbedtls/ssl.h b/crypto/mbedtls/include/mbedtls/ssl.h
index 55aef7fba9..69fea9384d 100644
--- a/crypto/mbedtls/include/mbedtls/ssl.h
+++ b/crypto/mbedtls/include/mbedtls/ssl.h
@@ -121,6 +121,7 @@
 #define MBEDTLS_ERR_SSL_INVALID_VERIFY_HASH               -0x6600  /**< Couldn't set the hash for verifying CertificateVerify */
 #define MBEDTLS_ERR_SSL_CONTINUE_PROCESSING               -0x6580  /**< Internal-only message signaling that further message-processing should be done */
 #define MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS                 -0x6500  /**< The asynchronous operation is not completed yet. */
+#define MBEDTLS_ERR_SSL_EARLY_MESSAGE                     -0x6480  /**< Internal-only message signaling that a message arrived early. */
 
 /*
  * Various constants
@@ -242,6 +243,14 @@
 #define MBEDTLS_SSL_OUT_CONTENT_LEN MBEDTLS_SSL_MAX_CONTENT_LEN
 #endif
 
+/*
+ * Maximum number of heap-allocated bytes for the purpose of
+ * DTLS handshake message reassembly and future message buffering.
+ */
+#if !defined(MBEDTLS_SSL_DTLS_MAX_BUFFERING)
+#define MBEDTLS_SSL_DTLS_MAX_BUFFERING 32768
+#endif
+
 /* \} name SECTION: Module settings */
 
 /*
@@ -1022,14 +1031,14 @@ struct mbedtls_ssl_context
     int renego_records_seen;    /*!< Records since renego request, or with DTLS,
                                   number of retransmissions of request if
                                   renego_max_records is < 0           */
-#endif
+#endif /* MBEDTLS_SSL_RENEGOTIATION */
 
     int major_ver;              /*!< equal to  MBEDTLS_SSL_MAJOR_VERSION_3    */
     int minor_ver;              /*!< either 0 (SSL3) or 1 (TLS1.0)    */
 
 #if defined(MBEDTLS_SSL_DTLS_BADMAC_LIMIT)
     unsigned badmac_seen;       /*!< records with a bad MAC received    */
-#endif
+#endif /* MBEDTLS_SSL_DTLS_BADMAC_LIMIT */
 
     mbedtls_ssl_send_t *f_send; /*!< Callback for network send */
     mbedtls_ssl_recv_t *f_recv; /*!< Callback for network receive */
@@ -1085,11 +1094,11 @@ struct mbedtls_ssl_context
     uint16_t in_epoch;          /*!< DTLS epoch for incoming records  */
     size_t next_record_offset;  /*!< offset of the next record in datagram
                                      (equal to in_left if none)       */
-#endif
+#endif /* MBEDTLS_SSL_PROTO_DTLS */
 #if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY)
     uint64_t in_window_top;     /*!< last validated record seq_num    */
     uint64_t in_window;         /*!< bitmask for replay detection     */
-#endif
+#endif /* MBEDTLS_SSL_DTLS_ANTI_REPLAY */
 
     size_t in_hslen;            /*!< current handshake message length,
                                      including the handshake header   */
@@ -1098,6 +1107,11 @@ struct mbedtls_ssl_context
     int keep_current_message;   /*!< drop or reuse current message
                                      on next call to record layer? */
 
+#if defined(MBEDTLS_SSL_PROTO_DTLS)
+    uint8_t disable_datagram_packing;  /*!< Disable packing multiple records
+                                        *   within a single datagram.  */
+#endif /* MBEDTLS_SSL_PROTO_DTLS */
+
     /*
      * Record layer (outgoing data)
      */
@@ -1112,12 +1126,18 @@ struct mbedtls_ssl_context
     size_t out_msglen;          /*!< record header: message length    */
     size_t out_left;            /*!< amount of data not yet written   */
 
+    unsigned char cur_out_ctr[8]; /*!<  Outgoing record sequence  number. */
+
+#if defined(MBEDTLS_SSL_PROTO_DTLS)
+    uint16_t mtu;               /*!< path mtu, used to fragment outgoing messages */
+#endif /* MBEDTLS_SSL_PROTO_DTLS */
+
 #if defined(MBEDTLS_ZLIB_SUPPORT)
     unsigned char *compress_buf;        /*!<  zlib data buffer        */
-#endif
+#endif /* MBEDTLS_ZLIB_SUPPORT */
 #if defined(MBEDTLS_SSL_CBC_RECORD_SPLITTING)
     signed char split_done;     /*!< current record already splitted? */
-#endif
+#endif /* MBEDTLS_SSL_CBC_RECORD_SPLITTING */
 
     /*
      * PKI layer
@@ -1130,11 +1150,11 @@ struct mbedtls_ssl_context
 #if defined(MBEDTLS_X509_CRT_PARSE_C)
     char *hostname;             /*!< expected peer CN for verification
                                      (and SNI if available)                 */
-#endif
+#endif /* MBEDTLS_X509_CRT_PARSE_C */
 
 #if defined(MBEDTLS_SSL_ALPN)
     const char *alpn_chosen;    /*!<  negotiated protocol                   */
-#endif
+#endif /* MBEDTLS_SSL_ALPN */
 
     /*
      * Information for DTLS hello verify
@@ -1142,7 +1162,7 @@ struct mbedtls_ssl_context
 #if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY) && defined(MBEDTLS_SSL_SRV_C)
     unsigned char  *cli_id;         /*!<  transport-level ID of the client  */
     size_t          cli_id_len;     /*!<  length of cli_id                  */
-#endif
+#endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY && MBEDTLS_SSL_SRV_C */
 
     /*
      * Secure renegotiation
@@ -1154,7 +1174,7 @@ struct mbedtls_ssl_context
     size_t verify_data_len;             /*!<  length of verify data stored   */
     char own_verify_data[MBEDTLS_SSL_VERIFY_DATA_MAX_LEN]; /*!<  previous handshake verify data */
     char peer_verify_data[MBEDTLS_SSL_VERIFY_DATA_MAX_LEN]; /*!<  previous handshake verify data */
-#endif
+#endif /* MBEDTLS_SSL_RENEGOTIATION */
 };
 
 #if defined(MBEDTLS_SSL_HW_RECORD_ACCEL)
@@ -1374,6 +1394,52 @@ void mbedtls_ssl_set_bio( mbedtls_ssl_context *ssl,
                           mbedtls_ssl_recv_t *f_recv,
                           mbedtls_ssl_recv_timeout_t *f_recv_timeout );
 
+#if defined(MBEDTLS_SSL_PROTO_DTLS)
+/**
+ * \brief          Set the Maximum Tranport Unit (MTU).
+ *                 Special value: 0 means unset (no limit).
+ *                 This represents the maximum size of a datagram payload
+ *                 handled by the transport layer (usually UDP) as determined
+ *                 by the network link and stack. In practice, this controls
+ *                 the maximum size datagram the DTLS layer will pass to the
+ *                 \c f_send() callback set using \c mbedtls_ssl_set_bio().
+ *
+ * \note           The limit on datagram size is converted to a limit on
+ *                 record payload by subtracting the current overhead of
+ *                 encapsulation and encryption/authentication if any.
+ *
+ * \note           This can be called at any point during the connection, for
+ *                 example when a Path Maximum Transfer Unit (PMTU)
+ *                 estimate becomes available from other sources,
+ *                 such as lower (or higher) protocol layers.
+ *
+ * \note           This setting only controls the size of the packets we send,
+ *                 and does not restrict the size of the datagrams we're
+ *                 willing to receive. Client-side, you can request the
+ *                 server to use smaller records with \c
+ *                 mbedtls_ssl_conf_max_frag_len().
+ *
+ * \note           If both a MTU and a maximum fragment length have been
+ *                 configured (or negotiated with the peer), the resulting
+ *                 lower limit on record payload (see first note) is used.
+ *
+ * \note           This can only be used to decrease the maximum size
+ *                 of datagrams (hence records, see first note) sent. It
+ *                 cannot be used to increase the maximum size of records over
+ *                 the limit set by #MBEDTLS_SSL_OUT_CONTENT_LEN.
+ *
+ * \note           Values lower than the current record layer expansion will
+ *                 result in an error when trying to send data.
+ *
+ * \note           Using record compression together with a non-zero MTU value
+ *                 will result in an error when trying to send data.
+ *
+ * \param ssl      SSL context
+ * \param mtu      Value of the path MTU in bytes
+ */
+void mbedtls_ssl_set_mtu( mbedtls_ssl_context *ssl, uint16_t mtu );
+#endif /* MBEDTLS_SSL_PROTO_DTLS */
+
 /**
  * \brief          Set the timeout period for mbedtls_ssl_read()
  *                 (Default: no timeout.)
@@ -1757,6 +1823,38 @@ void mbedtls_ssl_conf_dtls_badmac_limit( mbedtls_ssl_config *conf, unsigned limi
 #endif /* MBEDTLS_SSL_DTLS_BADMAC_LIMIT */
 
 #if defined(MBEDTLS_SSL_PROTO_DTLS)
+
+/**
+ * \brief          Allow or disallow packing of multiple handshake records
+ *                 within a single datagram.
+ *
+ * \param ssl           The SSL context to configure.
+ * \param allow_packing This determines whether datagram packing may
+ *                      be used or not. A value of \c 0 means that every
+ *                      record will be sent in a separate datagram; a
+ *                      value of \c 1 means that, if space permits,
+ *                      multiple handshake messages (including CCS) belonging to
+ *                      a single flight may be packed within a single datagram.
+ *
+ * \note           This is enabled by default and should only be disabled
+ *                 for test purposes, or if datagram packing causes
+ *                 interoperability issues with peers that don't support it.
+ *
+ * \note           Allowing datagram packing reduces the network load since
+ *                 there's less overhead if multiple messages share the same
+ *                 datagram. Also, it increases the handshake efficiency
+ *                 since messages belonging to a single datagram will not
+ *                 be reordered in transit, and so future message buffering
+ *                 or flight retransmission (if no buffering is used) as
+ *                 means to deal with reordering are needed less frequently.
+ *
+ * \note           Application records are not affected by this option and
+ *                 are currently always sent in separate datagrams.
+ *
+ */
+void mbedtls_ssl_set_datagram_packing( mbedtls_ssl_context *ssl,
+                                       unsigned allow_packing );
+
 /**
  * \brief          Set retransmit timeout values for the DTLS handshake.
  *                 (DTLS only, no effect on TLS.)
@@ -2433,6 +2531,18 @@ void mbedtls_ssl_conf_cert_req_ca_list( mbedtls_ssl_config *conf,
  *                 (Client: set maximum fragment length to emit *and*
  *                 negotiate with the server during handshake)
  *
+ * \note           With TLS, this currently only affects ApplicationData (sent
+ *                 with \c mbedtls_ssl_read()), not handshake messages.
+ *                 With DTLS, this affects both ApplicationData and handshake.
+ *
+ * \note           This sets the maximum length for a record's payload,
+ *                 excluding record overhead that will be added to it, see
+ *                 \c mbedtls_ssl_get_record_expansion().
+ *
+ * \note           For DTLS, it is also possible to set a limit for the total
+ *                 size of daragrams passed to the transport layer, including
+ *                 record overhead, see \c mbedtls_ssl_set_mtu().
+ *
  * \param conf     SSL configuration
  * \param mfl_code Code for maximum fragment length (allowed values:
  *                 MBEDTLS_SSL_MAX_FRAG_LEN_512,  MBEDTLS_SSL_MAX_FRAG_LEN_1024,
@@ -2695,6 +2805,9 @@ const char *mbedtls_ssl_get_version( const mbedtls_ssl_context *ssl );
  * \brief          Return the (maximum) number of bytes added by the record
  *                 layer: header + encryption/MAC overhead (inc. padding)
  *
+ * \note           This function is not available (always returns an error)
+ *                 when record compression is enabled.
+ *
  * \param ssl      SSL context
  *
  * \return         Current maximum record expansion in bytes, or
@@ -2709,6 +2822,23 @@ int mbedtls_ssl_get_record_expansion( const mbedtls_ssl_context *ssl );
  *                 This is the value negotiated with peer if any,
  *                 or the locally configured value.
  *
+ * \sa             mbedtls_ssl_conf_max_frag_len()
+ * \sa             mbedtls_ssl_get_max_record_payload()
+ *
+ * \param ssl      SSL context
+ *
+ * \return         Current maximum fragment length.
+ */
+size_t mbedtls_ssl_get_max_frag_len( const mbedtls_ssl_context *ssl );
+#endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
+
+/**
+ * \brief          Return the current maximum outgoing record payload in bytes.
+ *                 This takes into account the config.h setting \c
+ *                 MBEDTLS_SSL_OUT_CONTENT_LEN, the configured and negotiated
+ *                 max fragment length extension if used, and for DTLS the
+ *                 path MTU as configured and current record expansion.
+ *
  * \note           With DTLS, \c mbedtls_ssl_write() will return an error if
  *                 called with a larger length value.
  *                 With TLS, \c mbedtls_ssl_write() will fragment the input if
@@ -2716,12 +2846,19 @@ int mbedtls_ssl_get_record_expansion( const mbedtls_ssl_context *ssl );
  *                 to the caller to call \c mbedtls_ssl_write() again in
  *                 order to send the remaining bytes if any.
  *
+ * \note           This function is not available (always returns an error)
+ *                 when record compression is enabled.
+ *
+ * \sa             mbedtls_ssl_set_mtu()
+ * \sa             mbedtls_ssl_get_max_frag_len()
+ * \sa             mbedtls_ssl_get_record_expansion()
+ *
  * \param ssl      SSL context
  *
- * \return         Current maximum fragment length.
+ * \return         Current maximum payload for an outgoing record,
+ *                 or a negative error code.
  */
-size_t mbedtls_ssl_get_max_frag_len( const mbedtls_ssl_context *ssl );
-#endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
+int mbedtls_ssl_get_max_out_record_payload( const mbedtls_ssl_context *ssl );
 
 #if defined(MBEDTLS_X509_CRT_PARSE_C)
 /**
diff --git a/crypto/mbedtls/include/mbedtls/ssl_cookie.h b/crypto/mbedtls/include/mbedtls/ssl_cookie.h
index 80b65bbbb9..6a0ad4fa96 100644
--- a/crypto/mbedtls/include/mbedtls/ssl_cookie.h
+++ b/crypto/mbedtls/include/mbedtls/ssl_cookie.h
@@ -50,7 +50,7 @@ extern "C" {
 /**
  * \brief          Context for the default cookie functions.
  */
-typedef struct
+typedef struct mbedtls_ssl_cookie_ctx
 {
     mbedtls_md_context_t    hmac_ctx;   /*!< context for the HMAC portion   */
 #if !defined(MBEDTLS_HAVE_TIME)
diff --git a/crypto/mbedtls/include/mbedtls/ssl_internal.h b/crypto/mbedtls/include/mbedtls/ssl_internal.h
index d214703d77..4b4417a5fa 100644
--- a/crypto/mbedtls/include/mbedtls/ssl_internal.h
+++ b/crypto/mbedtls/include/mbedtls/ssl_internal.h
@@ -155,6 +155,9 @@
 #define MBEDTLS_SSL_OUT_PAYLOAD_LEN ( MBEDTLS_SSL_PAYLOAD_OVERHEAD + \
                                       ( MBEDTLS_SSL_OUT_CONTENT_LEN ) )
 
+/* The maximum number of buffered handshake messages. */
+#define MBEDTLS_SSL_MAX_BUFFERED_HS 4
+
 /* Maximum length we can advertise as our max content length for
    RFC 6066 max_fragment_length extension negotiation purposes
    (the lesser of both sizes, if they are unequal.)
@@ -294,18 +297,45 @@ struct mbedtls_ssl_handshake_params
     unsigned char verify_cookie_len;    /*!<  Cli: cookie length
                                               Srv: flag for sending a cookie */
 
-    unsigned char *hs_msg;              /*!<  Reassembled handshake message  */
-
     uint32_t retransmit_timeout;        /*!<  Current value of timeout       */
     unsigned char retransmit_state;     /*!<  Retransmission state           */
-    mbedtls_ssl_flight_item *flight;            /*!<  Current outgoing flight        */
-    mbedtls_ssl_flight_item *cur_msg;           /*!<  Current message in flight      */
+    mbedtls_ssl_flight_item *flight;    /*!<  Current outgoing flight        */
+    mbedtls_ssl_flight_item *cur_msg;   /*!<  Current message in flight      */
+    unsigned char *cur_msg_p;           /*!<  Position in current message    */
     unsigned int in_flight_start_seq;   /*!<  Minimum message sequence in the
                                               flight being received          */
     mbedtls_ssl_transform *alt_transform_out;   /*!<  Alternative transform for
                                               resending messages             */
     unsigned char alt_out_ctr[8];       /*!<  Alternative record epoch/counter
                                               for resending messages         */
+
+    struct
+    {
+        size_t total_bytes_buffered; /*!< Cumulative size of heap allocated
+                                      *   buffers used for message buffering. */
+
+        uint8_t seen_ccs;               /*!< Indicates if a CCS message has
+                                         *   been seen in the current flight. */
+
+        struct mbedtls_ssl_hs_buffer
+        {
+            unsigned is_valid      : 1;
+            unsigned is_fragmented : 1;
+            unsigned is_complete   : 1;
+            unsigned char *data;
+            size_t data_len;
+        } hs[MBEDTLS_SSL_MAX_BUFFERED_HS];
+
+        struct
+        {
+            unsigned char *data;
+            size_t len;
+            unsigned epoch;
+        } future_record;
+
+    } buffering;
+
+    uint16_t mtu;                       /*!<  Handshake mtu, used to fragment outgoing messages */
 #endif /* MBEDTLS_SSL_PROTO_DTLS */
 
     /*
@@ -364,6 +394,8 @@ struct mbedtls_ssl_handshake_params
 #endif /* MBEDTLS_SSL_ASYNC_PRIVATE */
 };
 
+typedef struct mbedtls_ssl_hs_buffer mbedtls_ssl_hs_buffer;
+
 /*
  * This structure contains a full set of runtime transform parameters
  * either in negotiation or active.
@@ -478,7 +510,6 @@ int mbedtls_ssl_send_fatal_handshake_failure( mbedtls_ssl_context *ssl );
 void mbedtls_ssl_reset_checksum( mbedtls_ssl_context *ssl );
 int mbedtls_ssl_derive_keys( mbedtls_ssl_context *ssl );
 
-int mbedtls_ssl_read_record_layer( mbedtls_ssl_context *ssl );
 int mbedtls_ssl_handle_message_type( mbedtls_ssl_context *ssl );
 int mbedtls_ssl_prepare_handshake_record( mbedtls_ssl_context *ssl );
 void mbedtls_ssl_update_handshake_status( mbedtls_ssl_context *ssl );
@@ -490,7 +521,10 @@ void mbedtls_ssl_update_handshake_status( mbedtls_ssl_context *ssl );
  *              of the logic of (D)TLS from the implementation
  *              of the secure transport.
  *
- * \param  ssl  SSL context to use
+ * \param  ssl              The SSL context to use.
+ * \param  update_hs_digest This indicates if the handshake digest
+ *                          should be automatically updated in case
+ *                          a handshake message is found.
  *
  * \return      0 or non-zero error code.
  *
@@ -556,10 +590,12 @@ void mbedtls_ssl_update_handshake_status( mbedtls_ssl_context *ssl );
  *              following the above definition.
  *
  */
-int mbedtls_ssl_read_record( mbedtls_ssl_context *ssl );
+int mbedtls_ssl_read_record( mbedtls_ssl_context *ssl,
+                             unsigned update_hs_digest );
 int mbedtls_ssl_fetch_input( mbedtls_ssl_context *ssl, size_t nb_want );
 
-int mbedtls_ssl_write_record( mbedtls_ssl_context *ssl );
+int mbedtls_ssl_write_handshake_msg( mbedtls_ssl_context *ssl );
+int mbedtls_ssl_write_record( mbedtls_ssl_context *ssl, uint8_t force_flush );
 int mbedtls_ssl_flush_output( mbedtls_ssl_context *ssl );
 
 int mbedtls_ssl_parse_certificate( mbedtls_ssl_context *ssl );
@@ -668,6 +704,7 @@ static inline size_t mbedtls_ssl_hs_hdr_len( const mbedtls_ssl_context *ssl )
 void mbedtls_ssl_send_flight_completed( mbedtls_ssl_context *ssl );
 void mbedtls_ssl_recv_flight_completed( mbedtls_ssl_context *ssl );
 int mbedtls_ssl_resend( mbedtls_ssl_context *ssl );
+int mbedtls_ssl_flight_transmit( mbedtls_ssl_context *ssl );
 #endif
 
 /* Visible for testing purposes only */
diff --git a/crypto/mbedtls/include/mbedtls/ssl_ticket.h b/crypto/mbedtls/include/mbedtls/ssl_ticket.h
index 93ad46ac9c..b2686df09f 100644
--- a/crypto/mbedtls/include/mbedtls/ssl_ticket.h
+++ b/crypto/mbedtls/include/mbedtls/ssl_ticket.h
@@ -44,7 +44,7 @@ extern "C" {
 /**
  * \brief   Information for session ticket protection
  */
-typedef struct
+typedef struct mbedtls_ssl_ticket_key
 {
     unsigned char name[4];          /*!< random key identifier              */
     uint32_t generation_time;       /*!< key generation timestamp (seconds) */
@@ -55,7 +55,7 @@ mbedtls_ssl_ticket_key;
 /**
  * \brief   Context for session ticket handling functions
  */
-typedef struct
+typedef struct mbedtls_ssl_ticket_context
 {
     mbedtls_ssl_ticket_key keys[2]; /*!< ticket protection keys             */
     unsigned char active;           /*!< index of the currently active key  */
diff --git a/crypto/mbedtls/include/mbedtls/threading.h b/crypto/mbedtls/include/mbedtls/threading.h
index c25daa5cdf..5112ebb747 100644
--- a/crypto/mbedtls/include/mbedtls/threading.h
+++ b/crypto/mbedtls/include/mbedtls/threading.h
@@ -42,7 +42,7 @@ extern "C" {
 
 #if defined(MBEDTLS_THREADING_PTHREAD)
 #include <pthread.h>
-typedef struct
+typedef struct mbedtls_threading_mutex_t
 {
     pthread_mutex_t mutex;
     char is_valid;
diff --git a/crypto/mbedtls/include/mbedtls/timing.h b/crypto/mbedtls/include/mbedtls/timing.h
index bbcb90688a..a965fe0d35 100644
--- a/crypto/mbedtls/include/mbedtls/timing.h
+++ b/crypto/mbedtls/include/mbedtls/timing.h
@@ -51,7 +51,7 @@ struct mbedtls_timing_hr_time
 /**
  * \brief          Context for mbedtls_timing_set/get_delay()
  */
-typedef struct
+typedef struct mbedtls_timing_delay_context
 {
     struct mbedtls_timing_hr_time   timer;
     uint32_t                        int_ms;
diff --git a/crypto/mbedtls/include/mbedtls/version.h b/crypto/mbedtls/include/mbedtls/version.h
index eaf25d908c..17b8ba450b 100644
--- a/crypto/mbedtls/include/mbedtls/version.h
+++ b/crypto/mbedtls/include/mbedtls/version.h
@@ -39,7 +39,7 @@
  * Major, Minor, Patchlevel
  */
 #define MBEDTLS_VERSION_MAJOR  2
-#define MBEDTLS_VERSION_MINOR  12
+#define MBEDTLS_VERSION_MINOR  13
 #define MBEDTLS_VERSION_PATCH  0
 
 /**
@@ -47,9 +47,9 @@
  *    MMNNPP00
  *    Major version | Minor version | Patch version
  */
-#define MBEDTLS_VERSION_NUMBER         0x020C0000
-#define MBEDTLS_VERSION_STRING         "2.12.0"
-#define MBEDTLS_VERSION_STRING_FULL    "mbed TLS 2.12.0"
+#define MBEDTLS_VERSION_NUMBER         0x020D0000
+#define MBEDTLS_VERSION_STRING         "2.13.0"
+#define MBEDTLS_VERSION_STRING_FULL    "mbed TLS 2.13.0"
 
 #if defined(MBEDTLS_VERSION_C)
 
diff --git a/crypto/mbedtls/include/mbedtls/x509_crt.h b/crypto/mbedtls/include/mbedtls/x509_crt.h
index ac23cffe84..d41ec93a66 100644
--- a/crypto/mbedtls/include/mbedtls/x509_crt.h
+++ b/crypto/mbedtls/include/mbedtls/x509_crt.h
@@ -105,7 +105,7 @@ mbedtls_x509_crt;
  *
  * All lists are bitfields, built by ORing flags from MBEDTLS_X509_ID_FLAG().
  */
-typedef struct
+typedef struct mbedtls_x509_crt_profile
 {
     uint32_t allowed_mds;       /**< MDs for signatures         */
     uint32_t allowed_pks;       /**< PK algs for signatures     */
diff --git a/crypto/mbedtls/include/mbedtls/xtea.h b/crypto/mbedtls/include/mbedtls/xtea.h
index 8df708a3a5..c70c3fe265 100644
--- a/crypto/mbedtls/include/mbedtls/xtea.h
+++ b/crypto/mbedtls/include/mbedtls/xtea.h
@@ -50,7 +50,7 @@ extern "C" {
 /**
  * \brief          XTEA context structure
  */
-typedef struct
+typedef struct mbedtls_xtea_context
 {
     uint32_t k[4];       /*!< key */
 }
diff --git a/crypto/mbedtls/src/aria.c b/crypto/mbedtls/src/aria.c
index e9bcd6d135..ca9e147f0d 100644
--- a/crypto/mbedtls/src/aria.c
+++ b/crypto/mbedtls/src/aria.c
@@ -875,11 +875,11 @@ static const uint8_t aria_test2_ctr_ct[3][48] =         // CTR ciphertext
 #define ARIA_SELF_TEST_IF_FAIL              \
         {                                   \
             if( verbose )                   \
-                printf( "failed\n" );       \
+                mbedtls_printf( "failed\n" );       \
             return( 1 );                    \
         } else {                            \
             if( verbose )                   \
-                printf( "passed\n" );       \
+                mbedtls_printf( "passed\n" );       \
         }
 
 /*
@@ -908,7 +908,7 @@ int mbedtls_aria_self_test( int verbose )
     {
         /* test ECB encryption */
         if( verbose )
-            printf( "  ARIA-ECB-%d (enc): ", 128 + 64 * i );
+            mbedtls_printf( "  ARIA-ECB-%d (enc): ", 128 + 64 * i );
         mbedtls_aria_setkey_enc( &ctx, aria_test1_ecb_key, 128 + 64 * i );
         mbedtls_aria_crypt_ecb( &ctx, aria_test1_ecb_pt, blk );
         if( memcmp( blk, aria_test1_ecb_ct[i], MBEDTLS_ARIA_BLOCKSIZE ) != 0 )
@@ -916,14 +916,14 @@ int mbedtls_aria_self_test( int verbose )
 
         /* test ECB decryption */
         if( verbose )
-            printf( "  ARIA-ECB-%d (dec): ", 128 + 64 * i );
+            mbedtls_printf( "  ARIA-ECB-%d (dec): ", 128 + 64 * i );
         mbedtls_aria_setkey_dec( &ctx, aria_test1_ecb_key, 128 + 64 * i );
         mbedtls_aria_crypt_ecb( &ctx, aria_test1_ecb_ct[i], blk );
         if( memcmp( blk, aria_test1_ecb_pt, MBEDTLS_ARIA_BLOCKSIZE ) != 0 )
             ARIA_SELF_TEST_IF_FAIL;
     }
     if( verbose )
-        printf( "\n" );
+        mbedtls_printf( "\n" );
 
     /*
      * Test set 2
@@ -933,7 +933,7 @@ int mbedtls_aria_self_test( int verbose )
     {
         /* Test CBC encryption */
         if( verbose )
-            printf( "  ARIA-CBC-%d (enc): ", 128 + 64 * i );
+            mbedtls_printf( "  ARIA-CBC-%d (enc): ", 128 + 64 * i );
         mbedtls_aria_setkey_enc( &ctx, aria_test2_key, 128 + 64 * i );
         memcpy( iv, aria_test2_iv, MBEDTLS_ARIA_BLOCKSIZE );
         memset( buf, 0x55, sizeof( buf ) );
@@ -944,7 +944,7 @@ int mbedtls_aria_self_test( int verbose )
 
         /* Test CBC decryption */
         if( verbose )
-            printf( "  ARIA-CBC-%d (dec): ", 128 + 64 * i );
+            mbedtls_printf( "  ARIA-CBC-%d (dec): ", 128 + 64 * i );
         mbedtls_aria_setkey_dec( &ctx, aria_test2_key, 128 + 64 * i );
         memcpy( iv, aria_test2_iv, MBEDTLS_ARIA_BLOCKSIZE );
         memset( buf, 0xAA, sizeof( buf ) );
@@ -954,7 +954,7 @@ int mbedtls_aria_self_test( int verbose )
             ARIA_SELF_TEST_IF_FAIL;
     }
     if( verbose )
-        printf( "\n" );
+        mbedtls_printf( "\n" );
 
 #endif /* MBEDTLS_CIPHER_MODE_CBC */
 
@@ -963,7 +963,7 @@ int mbedtls_aria_self_test( int verbose )
     {
         /* Test CFB encryption */
         if( verbose )
-            printf( "  ARIA-CFB-%d (enc): ", 128 + 64 * i );
+            mbedtls_printf( "  ARIA-CFB-%d (enc): ", 128 + 64 * i );
         mbedtls_aria_setkey_enc( &ctx, aria_test2_key, 128 + 64 * i );
         memcpy( iv, aria_test2_iv, MBEDTLS_ARIA_BLOCKSIZE );
         memset( buf, 0x55, sizeof( buf ) );
@@ -975,7 +975,7 @@ int mbedtls_aria_self_test( int verbose )
 
         /* Test CFB decryption */
         if( verbose )
-            printf( "  ARIA-CFB-%d (dec): ", 128 + 64 * i );
+            mbedtls_printf( "  ARIA-CFB-%d (dec): ", 128 + 64 * i );
         mbedtls_aria_setkey_enc( &ctx, aria_test2_key, 128 + 64 * i );
         memcpy( iv, aria_test2_iv, MBEDTLS_ARIA_BLOCKSIZE );
         memset( buf, 0xAA, sizeof( buf ) );
@@ -986,7 +986,7 @@ int mbedtls_aria_self_test( int verbose )
             ARIA_SELF_TEST_IF_FAIL;
     }
     if( verbose )
-        printf( "\n" );
+        mbedtls_printf( "\n" );
 #endif /* MBEDTLS_CIPHER_MODE_CFB */
 
 #if defined(MBEDTLS_CIPHER_MODE_CTR)
@@ -994,7 +994,7 @@ int mbedtls_aria_self_test( int verbose )
     {
         /* Test CTR encryption */
         if( verbose )
-            printf( "  ARIA-CTR-%d (enc): ", 128 + 64 * i );
+            mbedtls_printf( "  ARIA-CTR-%d (enc): ", 128 + 64 * i );
         mbedtls_aria_setkey_enc( &ctx, aria_test2_key, 128 + 64 * i );
         memset( iv, 0, MBEDTLS_ARIA_BLOCKSIZE );                    // IV = 0
         memset( buf, 0x55, sizeof( buf ) );
@@ -1006,7 +1006,7 @@ int mbedtls_aria_self_test( int verbose )
 
         /* Test CTR decryption */
         if( verbose )
-            printf( "  ARIA-CTR-%d (dec): ", 128 + 64 * i );
+            mbedtls_printf( "  ARIA-CTR-%d (dec): ", 128 + 64 * i );
         mbedtls_aria_setkey_enc( &ctx, aria_test2_key, 128 + 64 * i );
         memset( iv, 0, MBEDTLS_ARIA_BLOCKSIZE );                    // IV = 0
         memset( buf, 0xAA, sizeof( buf ) );
@@ -1017,7 +1017,7 @@ int mbedtls_aria_self_test( int verbose )
             ARIA_SELF_TEST_IF_FAIL;
     }
     if( verbose )
-        printf( "\n" );
+        mbedtls_printf( "\n" );
 #endif /* MBEDTLS_CIPHER_MODE_CTR */
 
     return( 0 );
diff --git a/crypto/mbedtls/src/ccm.c b/crypto/mbedtls/src/ccm.c
index 804eaf80f1..90cab8e147 100644
--- a/crypto/mbedtls/src/ccm.c
+++ b/crypto/mbedtls/src/ccm.c
@@ -381,7 +381,8 @@ int mbedtls_ccm_auth_decrypt( mbedtls_ccm_context *ctx, size_t length,
  */
 
 #define NB_TESTS 3
-
+#define CCM_SELFTEST_PT_MAX_LEN 24
+#define CCM_SELFTEST_CT_MAX_LEN 32
 /*
  * The data is the same for all tests, only the used length changes
  */
@@ -401,7 +402,7 @@ static const unsigned char ad[] = {
     0x10, 0x11, 0x12, 0x13
 };
 
-static const unsigned char msg[] = {
+static const unsigned char msg[CCM_SELFTEST_PT_MAX_LEN] = {
     0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27,
     0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
     0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,
@@ -412,7 +413,7 @@ static const size_t add_len[NB_TESTS] = { 8, 16, 20 };
 static const size_t msg_len[NB_TESTS] = { 4, 16, 24 };
 static const size_t tag_len[NB_TESTS] = { 4, 6,  8  };
 
-static const unsigned char res[NB_TESTS][32] = {
+static const unsigned char res[NB_TESTS][CCM_SELFTEST_CT_MAX_LEN] = {
     {   0x71, 0x62, 0x01, 0x5b, 0x4d, 0xac, 0x25, 0x5d },
     {   0xd2, 0xa1, 0xf0, 0xe0, 0x51, 0xea, 0x5f, 0x62,
         0x08, 0x1a, 0x77, 0x92, 0x07, 0x3d, 0x59, 0x3d,
@@ -426,7 +427,13 @@ static const unsigned char res[NB_TESTS][32] = {
 int mbedtls_ccm_self_test( int verbose )
 {
     mbedtls_ccm_context ctx;
-    unsigned char out[32];
+    /*
+     * Some hardware accelerators require the input and output buffers
+     * would be in RAM, because the flash is not accessible.
+     * Use buffers on the stack to hold the test vectors data.
+     */
+    unsigned char plaintext[CCM_SELFTEST_PT_MAX_LEN];
+    unsigned char ciphertext[CCM_SELFTEST_CT_MAX_LEN];
     size_t i;
     int ret;
 
@@ -445,27 +452,32 @@ int mbedtls_ccm_self_test( int verbose )
         if( verbose != 0 )
             mbedtls_printf( "  CCM-AES #%u: ", (unsigned int) i + 1 );
 
+        memset( plaintext, 0, CCM_SELFTEST_PT_MAX_LEN );
+        memset( ciphertext, 0, CCM_SELFTEST_CT_MAX_LEN );
+        memcpy( plaintext, msg, msg_len[i] );
+
         ret = mbedtls_ccm_encrypt_and_tag( &ctx, msg_len[i],
-                                   iv, iv_len[i], ad, add_len[i],
-                                   msg, out,
-                                   out + msg_len[i], tag_len[i] );
+                                           iv, iv_len[i], ad, add_len[i],
+                                           plaintext, ciphertext,
+                                           ciphertext + msg_len[i], tag_len[i] );
 
         if( ret != 0 ||
-            memcmp( out, res[i], msg_len[i] + tag_len[i] ) != 0 )
+            memcmp( ciphertext, res[i], msg_len[i] + tag_len[i] ) != 0 )
         {
             if( verbose != 0 )
                 mbedtls_printf( "failed\n" );
 
             return( 1 );
         }
+        memset( plaintext, 0, CCM_SELFTEST_PT_MAX_LEN );
 
         ret = mbedtls_ccm_auth_decrypt( &ctx, msg_len[i],
-                                iv, iv_len[i], ad, add_len[i],
-                                res[i], out,
-                                res[i] + msg_len[i], tag_len[i] );
+                                        iv, iv_len[i], ad, add_len[i],
+                                        ciphertext, plaintext,
+                                        ciphertext + msg_len[i], tag_len[i] );
 
         if( ret != 0 ||
-            memcmp( out, msg, msg_len[i] ) != 0 )
+            memcmp( plaintext, msg, msg_len[i] ) != 0 )
         {
             if( verbose != 0 )
                 mbedtls_printf( "failed\n" );
diff --git a/crypto/mbedtls/src/ecp.c b/crypto/mbedtls/src/ecp.c
index 41db3fbe5b..9e2c085bb6 100644
--- a/crypto/mbedtls/src/ecp.c
+++ b/crypto/mbedtls/src/ecp.c
@@ -1446,7 +1446,12 @@ static int ecp_mul_comb( mbedtls_ecp_group *grp, mbedtls_ecp_point *R,
 
 cleanup:
 
-    if( T != NULL && ! p_eq_g )
+    /* There are two cases where T is not stored in grp:
+     * - P != G
+     * - An intermediate operation failed before setting grp->T
+     * In either case, T must be freed.
+     */
+    if( T != NULL && T != grp->T )
     {
         for( i = 0; i < pre_len; i++ )
             mbedtls_ecp_point_free( &T[i] );
@@ -1892,7 +1897,6 @@ int mbedtls_ecp_check_privkey( const mbedtls_ecp_group *grp, const mbedtls_mpi *
             mbedtls_mpi_get_bit( d, 1 ) != 0 ||
             mbedtls_mpi_bitlen( d ) - 1 != grp->nbits ) /* mbedtls_mpi_bitlen is one-based! */
             return( MBEDTLS_ERR_ECP_INVALID_KEY );
-        else
 
         /* see [Curve25519] page 5 */
         if( grp->nbits == 254 && mbedtls_mpi_get_bit( d, 2 ) != 0 )
diff --git a/crypto/mbedtls/src/error.c b/crypto/mbedtls/src/error.c
index 774244b454..6c88689190 100644
--- a/crypto/mbedtls/src/error.c
+++ b/crypto/mbedtls/src/error.c
@@ -515,6 +515,8 @@ void mbedtls_strerror( int ret, char *buf, size_t buflen )
             mbedtls_snprintf( buf, buflen, "SSL - Internal-only message signaling that further message-processing should be done" );
         if( use_ret == -(MBEDTLS_ERR_SSL_ASYNC_IN_PROGRESS) )
             mbedtls_snprintf( buf, buflen, "SSL - The asynchronous operation is not completed yet" );
+        if( use_ret == -(MBEDTLS_ERR_SSL_EARLY_MESSAGE) )
+            mbedtls_snprintf( buf, buflen, "SSL - Internal-only message signaling that a message arrived early" );
 #endif /* MBEDTLS_SSL_TLS_C */
 
 #if defined(MBEDTLS_X509_USE_C) || defined(MBEDTLS_X509_CREATE_C)
diff --git a/crypto/mbedtls/src/ssl_ciphersuites.c b/crypto/mbedtls/src/ssl_ciphersuites.c
index 59cdc7a806..745474effe 100644
--- a/crypto/mbedtls/src/ssl_ciphersuites.c
+++ b/crypto/mbedtls/src/ssl_ciphersuites.c
@@ -2320,7 +2320,8 @@ mbedtls_pk_type_t mbedtls_ssl_get_ciphersuite_sig_alg( const mbedtls_ssl_ciphers
 
 #endif /* MBEDTLS_PK_C */
 
-#if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C)
+#if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
+    defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
 int mbedtls_ssl_ciphersuite_uses_ec( const mbedtls_ssl_ciphersuite_t *info )
 {
     switch( info->key_exchange )
@@ -2330,13 +2331,14 @@ int mbedtls_ssl_ciphersuite_uses_ec( const mbedtls_ssl_ciphersuite_t *info )
         case MBEDTLS_KEY_EXCHANGE_ECDHE_PSK:
         case MBEDTLS_KEY_EXCHANGE_ECDH_RSA:
         case MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA:
+        case MBEDTLS_KEY_EXCHANGE_ECJPAKE:
             return( 1 );
 
         default:
             return( 0 );
     }
 }
-#endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C */
+#endif /* MBEDTLS_ECDH_C || MBEDTLS_ECDSA_C || MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED*/
 
 #if defined(MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED)
 int mbedtls_ssl_ciphersuite_uses_psk( const mbedtls_ssl_ciphersuite_t *info )
diff --git a/crypto/mbedtls/src/ssl_cli.c b/crypto/mbedtls/src/ssl_cli.c
index ba59c48989..8385720115 100644
--- a/crypto/mbedtls/src/ssl_cli.c
+++ b/crypto/mbedtls/src/ssl_cli.c
@@ -766,6 +766,10 @@ static int ssl_write_client_hello( mbedtls_ssl_context *ssl )
     unsigned char offer_compress;
     const int *ciphersuites;
     const mbedtls_ssl_ciphersuite_t *ciphersuite_info;
+#if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
+    defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
+    int uses_ec = 0;
+#endif
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write client hello" ) );
 
@@ -917,6 +921,11 @@ static int ssl_write_client_hello( mbedtls_ssl_context *ssl )
         MBEDTLS_SSL_DEBUG_MSG( 3, ( "client hello, add ciphersuite: %04x",
                                     ciphersuites[i] ) );
 
+#if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
+    defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
+        uses_ec |= mbedtls_ssl_ciphersuite_uses_ec( ciphersuite_info );
+#endif
+
         n++;
         *p++ = (unsigned char)( ciphersuites[i] >> 8 );
         *p++ = (unsigned char)( ciphersuites[i]      );
@@ -1010,11 +1019,14 @@ static int ssl_write_client_hello( mbedtls_ssl_context *ssl )
 
 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
     defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
-    ssl_write_supported_elliptic_curves_ext( ssl, p + 2 + ext_len, &olen );
-    ext_len += olen;
+    if( uses_ec )
+    {
+        ssl_write_supported_elliptic_curves_ext( ssl, p + 2 + ext_len, &olen );
+        ext_len += olen;
 
-    ssl_write_supported_point_formats_ext( ssl, p + 2 + ext_len, &olen );
-    ext_len += olen;
+        ssl_write_supported_point_formats_ext( ssl, p + 2 + ext_len, &olen );
+        ext_len += olen;
+    }
 #endif
 
 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
@@ -1076,11 +1088,20 @@ static int ssl_write_client_hello( mbedtls_ssl_context *ssl )
         mbedtls_ssl_send_flight_completed( ssl );
 #endif
 
-    if( ( ret = mbedtls_ssl_write_record( ssl ) ) != 0 )
+    if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
+    {
+        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret );
+        return( ret );
+    }
+
+#if defined(MBEDTLS_SSL_PROTO_DTLS)
+    if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
+        ( ret = mbedtls_ssl_flight_transmit( ssl ) ) != 0 )
     {
-        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_record", ret );
+        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_flight_transmit", ret );
         return( ret );
     }
+#endif /* MBEDTLS_SSL_PROTO_DTLS */
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write client hello" ) );
 
@@ -1479,7 +1500,7 @@ static int ssl_parse_server_hello( mbedtls_ssl_context *ssl )
 
     buf = ssl->in_msg;
 
-    if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 )
+    if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
     {
         /* No alert on a read error. */
         MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret );
@@ -2328,7 +2349,7 @@ static int ssl_parse_server_key_exchange( mbedtls_ssl_context *ssl )
 #endif /* MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED ||
           MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED */
 
-    if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 )
+    if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
     {
         MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret );
         return( ret );
@@ -2635,7 +2656,7 @@ static int ssl_parse_certificate_request( mbedtls_ssl_context *ssl )
         return( 0 );
     }
 
-    if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 )
+    if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
     {
         MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret );
         return( ret );
@@ -2709,7 +2730,7 @@ static int ssl_parse_certificate_request( mbedtls_ssl_context *ssl )
      * therefore the buffer length at this point must be greater than that
      * regardless of the actual code path.
      */
-    if( ssl->in_hslen <= mbedtls_ssl_hs_hdr_len( ssl ) + 3 + n )
+    if( ssl->in_hslen <= mbedtls_ssl_hs_hdr_len( ssl ) + 2 + n )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad certificate request message" ) );
         mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
@@ -2787,7 +2808,7 @@ static int ssl_parse_server_hello_done( mbedtls_ssl_context *ssl )
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse server hello done" ) );
 
-    if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 )
+    if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
     {
         MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret );
         return( ret );
@@ -3063,9 +3084,9 @@ static int ssl_write_client_key_exchange( mbedtls_ssl_context *ssl )
 
     ssl->state++;
 
-    if( ( ret = mbedtls_ssl_write_record( ssl ) ) != 0 )
+    if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
     {
-        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_record", ret );
+        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret );
         return( ret );
     }
 
@@ -3248,9 +3269,9 @@ static int ssl_write_certificate_verify( mbedtls_ssl_context *ssl )
 
     ssl->state++;
 
-    if( ( ret = mbedtls_ssl_write_record( ssl ) ) != 0 )
+    if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
     {
-        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_record", ret );
+        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret );
         return( ret );
     }
 
@@ -3276,7 +3297,7 @@ static int ssl_parse_new_session_ticket( mbedtls_ssl_context *ssl )
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse new session ticket" ) );
 
-    if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 )
+    if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
     {
         MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret );
         return( ret );
@@ -3311,8 +3332,8 @@ static int ssl_parse_new_session_ticket( mbedtls_ssl_context *ssl )
 
     msg = ssl->in_msg + mbedtls_ssl_hs_hdr_len( ssl );
 
-    lifetime = ( msg[0] << 24 ) | ( msg[1] << 16 ) |
-               ( msg[2] <<  8 ) | ( msg[3]       );
+    lifetime = ( ((uint32_t) msg[0]) << 24 ) | ( msg[1] << 16 ) |
+               ( msg[2] << 8 ) | ( msg[3] );
 
     ticket_len = ( msg[4] << 8 ) | ( msg[5] );
 
@@ -3390,10 +3411,10 @@ int mbedtls_ssl_handshake_client_step( mbedtls_ssl_context *ssl )
     if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
         ssl->handshake->retransmit_state == MBEDTLS_SSL_RETRANS_SENDING )
     {
-        if( ( ret = mbedtls_ssl_resend( ssl ) ) != 0 )
+        if( ( ret = mbedtls_ssl_flight_transmit( ssl ) ) != 0 )
             return( ret );
     }
-#endif
+#endif /* MBEDTLS_SSL_PROTO_DTLS */
 
     /* Change state now, so that it is right in mbedtls_ssl_read_record(), used
      * by DTLS for dropping out-of-sequence ChangeCipherSpec records */
diff --git a/crypto/mbedtls/src/ssl_srv.c b/crypto/mbedtls/src/ssl_srv.c
index 52087ae6e1..36ca0d69f9 100644
--- a/crypto/mbedtls/src/ssl_srv.c
+++ b/crypto/mbedtls/src/ssl_srv.c
@@ -1294,7 +1294,7 @@ static int ssl_parse_client_hello( mbedtls_ssl_context *ssl )
             return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
         }
 
-        memcpy( ssl->out_ctr + 2, ssl->in_ctr + 2, 6 );
+        memcpy( ssl->cur_out_ctr + 2, ssl->in_ctr + 2, 6 );
 
 #if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY)
         if( mbedtls_ssl_dtls_replay_check( ssl ) != 0 )
@@ -2384,12 +2384,21 @@ static int ssl_write_hello_verify_request( mbedtls_ssl_context *ssl )
 
     ssl->state = MBEDTLS_SSL_SERVER_HELLO_VERIFY_REQUEST_SENT;
 
-    if( ( ret = mbedtls_ssl_write_record( ssl ) ) != 0 )
+    if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
     {
-        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_record", ret );
+        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret );
         return( ret );
     }
 
+#if defined(MBEDTLS_SSL_PROTO_DTLS)
+    if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
+        ( ret = mbedtls_ssl_flight_transmit( ssl ) ) != 0 )
+    {
+        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_flight_transmit", ret );
+        return( ret );
+    }
+#endif /* MBEDTLS_SSL_PROTO_DTLS */
+
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write hello verify request" ) );
 
     return( 0 );
@@ -2589,8 +2598,12 @@ static int ssl_write_server_hello( mbedtls_ssl_context *ssl )
 
 #if defined(MBEDTLS_ECDH_C) || defined(MBEDTLS_ECDSA_C) || \
     defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
-    ssl_write_supported_point_formats_ext( ssl, p + 2 + ext_len, &olen );
-    ext_len += olen;
+    if ( mbedtls_ssl_ciphersuite_uses_ec(
+         mbedtls_ssl_ciphersuite_from_id( ssl->session_negotiate->ciphersuite ) ) )
+    {
+        ssl_write_supported_point_formats_ext( ssl, p + 2 + ext_len, &olen );
+        ext_len += olen;
+    }
 #endif
 
 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
@@ -2620,7 +2633,7 @@ static int ssl_write_server_hello( mbedtls_ssl_context *ssl )
     ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
     ssl->out_msg[0]  = MBEDTLS_SSL_HS_SERVER_HELLO;
 
-    ret = mbedtls_ssl_write_record( ssl );
+    ret = mbedtls_ssl_write_handshake_msg( ssl );
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server hello" ) );
 
@@ -2815,7 +2828,7 @@ static int ssl_write_certificate_request( mbedtls_ssl_context *ssl )
     ssl->out_msg[4 + ct_len + sa_len] = (unsigned char)( total_dn_size  >> 8 );
     ssl->out_msg[5 + ct_len + sa_len] = (unsigned char)( total_dn_size       );
 
-    ret = mbedtls_ssl_write_record( ssl );
+    ret = mbedtls_ssl_write_handshake_msg( ssl );
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write certificate request" ) );
 
@@ -3332,9 +3345,9 @@ static int ssl_write_server_key_exchange( mbedtls_ssl_context *ssl )
 
     ssl->state++;
 
-    if( ( ret = mbedtls_ssl_write_record( ssl ) ) != 0 )
+    if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
     {
-        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_record", ret );
+        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret );
         return( ret );
     }
 
@@ -3359,11 +3372,20 @@ static int ssl_write_server_hello_done( mbedtls_ssl_context *ssl )
         mbedtls_ssl_send_flight_completed( ssl );
 #endif
 
-    if( ( ret = mbedtls_ssl_write_record( ssl ) ) != 0 )
+    if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
+    {
+        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret );
+        return( ret );
+    }
+
+#if defined(MBEDTLS_SSL_PROTO_DTLS)
+    if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
+        ( ret = mbedtls_ssl_flight_transmit( ssl ) ) != 0 )
     {
-        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_record", ret );
+        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_flight_transmit", ret );
         return( ret );
     }
+#endif /* MBEDTLS_SSL_PROTO_DTLS */
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write server hello done" ) );
 
@@ -3706,7 +3728,7 @@ static int ssl_parse_client_key_exchange( mbedtls_ssl_context *ssl )
     }
     else
 #endif
-    if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 )
+    if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
     {
         MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret );
         return( ret );
@@ -4016,25 +4038,10 @@ static int ssl_parse_certificate_verify( mbedtls_ssl_context *ssl )
     }
 
     /* Read the message without adding it to the checksum */
-    do {
-
-        do ret = mbedtls_ssl_read_record_layer( ssl );
-        while( ret == MBEDTLS_ERR_SSL_CONTINUE_PROCESSING );
-
-        if( ret != 0 )
-        {
-            MBEDTLS_SSL_DEBUG_RET( 1, ( "mbedtls_ssl_read_record_layer" ), ret );
-            return( ret );
-        }
-
-        ret = mbedtls_ssl_handle_message_type( ssl );
-
-    } while( MBEDTLS_ERR_SSL_NON_FATAL           == ret ||
-             MBEDTLS_ERR_SSL_CONTINUE_PROCESSING == ret );
-
+    ret = mbedtls_ssl_read_record( ssl, 0 /* no checksum update */ );
     if( 0 != ret )
     {
-        MBEDTLS_SSL_DEBUG_RET( 1, ( "mbedtls_ssl_handle_message_type" ), ret );
+        MBEDTLS_SSL_DEBUG_RET( 1, ( "mbedtls_ssl_read_record" ), ret );
         return( ret );
     }
 
@@ -4223,9 +4230,9 @@ static int ssl_write_new_session_ticket( mbedtls_ssl_context *ssl )
      */
     ssl->handshake->new_session_ticket = 0;
 
-    if( ( ret = mbedtls_ssl_write_record( ssl ) ) != 0 )
+    if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
     {
-        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_record", ret );
+        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret );
         return( ret );
     }
 
@@ -4254,10 +4261,10 @@ int mbedtls_ssl_handshake_server_step( mbedtls_ssl_context *ssl )
     if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
         ssl->handshake->retransmit_state == MBEDTLS_SSL_RETRANS_SENDING )
     {
-        if( ( ret = mbedtls_ssl_resend( ssl ) ) != 0 )
+        if( ( ret = mbedtls_ssl_flight_transmit( ssl ) ) != 0 )
             return( ret );
     }
-#endif
+#endif /* MBEDTLS_SSL_PROTO_DTLS */
 
     switch( ssl->state )
     {
diff --git a/crypto/mbedtls/src/ssl_tls.c b/crypto/mbedtls/src/ssl_tls.c
index 91f96c8ab6..8bd74db8d7 100644
--- a/crypto/mbedtls/src/ssl_tls.c
+++ b/crypto/mbedtls/src/ssl_tls.c
@@ -54,6 +54,9 @@
 #include "mbedtls/oid.h"
 #endif
 
+static void ssl_reset_in_out_pointers( mbedtls_ssl_context *ssl );
+static uint32_t ssl_get_hs_total_len( mbedtls_ssl_context const *ssl );
+
 /* Length of the "epoch" field in the record header */
 static inline size_t ssl_ep_len( const mbedtls_ssl_context *ssl )
 {
@@ -96,7 +99,101 @@ static int ssl_check_timer( mbedtls_ssl_context *ssl )
     return( 0 );
 }
 
+static void ssl_update_out_pointers( mbedtls_ssl_context *ssl,
+                                     mbedtls_ssl_transform *transform );
+static void ssl_update_in_pointers( mbedtls_ssl_context *ssl,
+                                    mbedtls_ssl_transform *transform );
+
+#define SSL_DONT_FORCE_FLUSH 0
+#define SSL_FORCE_FLUSH      1
+
 #if defined(MBEDTLS_SSL_PROTO_DTLS)
+
+/* Forward declarations for functions related to message buffering. */
+static void ssl_buffering_free( mbedtls_ssl_context *ssl );
+static void ssl_buffering_free_slot( mbedtls_ssl_context *ssl,
+                                     uint8_t slot );
+static void ssl_free_buffered_record( mbedtls_ssl_context *ssl );
+static int ssl_load_buffered_message( mbedtls_ssl_context *ssl );
+static int ssl_load_buffered_record( mbedtls_ssl_context *ssl );
+static int ssl_buffer_message( mbedtls_ssl_context *ssl );
+static int ssl_buffer_future_record( mbedtls_ssl_context *ssl );
+static int ssl_next_record_is_in_datagram( mbedtls_ssl_context *ssl );
+
+static size_t ssl_get_current_mtu( const mbedtls_ssl_context *ssl );
+static size_t ssl_get_maximum_datagram_size( mbedtls_ssl_context const *ssl )
+{
+    size_t mtu = ssl_get_current_mtu( ssl );
+
+    if( mtu != 0 && mtu < MBEDTLS_SSL_OUT_BUFFER_LEN )
+        return( mtu );
+
+    return( MBEDTLS_SSL_OUT_BUFFER_LEN );
+}
+
+static int ssl_get_remaining_space_in_datagram( mbedtls_ssl_context const *ssl )
+{
+    size_t const bytes_written = ssl->out_left;
+    size_t const mtu           = ssl_get_maximum_datagram_size( ssl );
+
+    /* Double-check that the write-index hasn't gone
+     * past what we can transmit in a single datagram. */
+    if( bytes_written > mtu )
+    {
+        /* Should never happen... */
+        return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
+    }
+
+    return( (int) ( mtu - bytes_written ) );
+}
+
+static int ssl_get_remaining_payload_in_datagram( mbedtls_ssl_context const *ssl )
+{
+    int ret;
+    size_t remaining, expansion;
+    size_t max_len = MBEDTLS_SSL_MAX_CONTENT_LEN;
+
+#if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
+    const size_t mfl = mbedtls_ssl_get_max_frag_len( ssl );
+
+    if( max_len > mfl )
+        max_len = mfl;
+
+    /* By the standard (RFC 6066 Sect. 4), the MFL extension
+     * only limits the maximum record payload size, so in theory
+     * we would be allowed to pack multiple records of payload size
+     * MFL into a single datagram. However, this would mean that there's
+     * no way to explicitly communicate MTU restrictions to the peer.
+     *
+     * The following reduction of max_len makes sure that we never
+     * write datagrams larger than MFL + Record Expansion Overhead.
+     */
+    if( max_len <= ssl->out_left )
+        return( 0 );
+
+    max_len -= ssl->out_left;
+#endif
+
+    ret = ssl_get_remaining_space_in_datagram( ssl );
+    if( ret < 0 )
+        return( ret );
+    remaining = (size_t) ret;
+
+    ret = mbedtls_ssl_get_record_expansion( ssl );
+    if( ret < 0 )
+        return( ret );
+    expansion = (size_t) ret;
+
+    if( remaining <= expansion )
+        return( 0 );
+
+    remaining -= expansion;
+    if( remaining >= max_len )
+        remaining = max_len;
+
+    return( (int) remaining );
+}
+
 /*
  * Double the retransmit timeout value, within the allowed range,
  * returning -1 if the maximum value has already been reached.
@@ -108,6 +205,15 @@ static int ssl_double_retransmit_timeout( mbedtls_ssl_context *ssl )
     if( ssl->handshake->retransmit_timeout >= ssl->conf->hs_timeout_max )
         return( -1 );
 
+    /* Implement the final paragraph of RFC 6347 section 4.1.1.1
+     * in the following way: after the initial transmission and a first
+     * retransmission, back off to a temporary estimated MTU of 508 bytes.
+     * This value is guaranteed to be deliverable (if not guaranteed to be
+     * delivered) of any compliant IPv4 (and IPv6) network, and should work
+     * on most non-IP stacks too. */
+    if( ssl->handshake->retransmit_timeout != ssl->conf->hs_timeout_min )
+        ssl->handshake->mtu = 508;
+
     new_timeout = 2 * ssl->handshake->retransmit_timeout;
 
     /* Avoid arithmetic overflow and range overflow */
@@ -1345,14 +1451,6 @@ static int ssl_encrypt_buf( mbedtls_ssl_context *ssl )
     MBEDTLS_SSL_DEBUG_BUF( 4, "before encrypt: output payload",
                       ssl->out_msg, ssl->out_msglen );
 
-    if( ssl->out_msglen > MBEDTLS_SSL_OUT_CONTENT_LEN )
-    {
-        MBEDTLS_SSL_DEBUG_MSG( 1, ( "Record content %u too large, maximum %d",
-                                    (unsigned) ssl->out_msglen,
-                                    MBEDTLS_SSL_OUT_CONTENT_LEN ) );
-        return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
-    }
-
     /*
      * Add MAC before if needed
      */
@@ -1626,6 +1724,8 @@ static int ssl_encrypt_buf( mbedtls_ssl_context *ssl )
 #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
         if( auth_done == 0 )
         {
+            unsigned char mac[MBEDTLS_SSL_MAC_ADD];
+
             /*
              * MAC(MAC_write_key, seq_num +
              *     TLSCipherText.type +
@@ -1648,10 +1748,12 @@ static int ssl_encrypt_buf( mbedtls_ssl_context *ssl )
             mbedtls_md_hmac_update( &ssl->transform_out->md_ctx_enc, pseudo_hdr, 13 );
             mbedtls_md_hmac_update( &ssl->transform_out->md_ctx_enc,
                              ssl->out_iv, ssl->out_msglen );
-            mbedtls_md_hmac_finish( &ssl->transform_out->md_ctx_enc,
-                             ssl->out_iv + ssl->out_msglen );
+            mbedtls_md_hmac_finish( &ssl->transform_out->md_ctx_enc, mac );
             mbedtls_md_hmac_reset( &ssl->transform_out->md_ctx_enc );
 
+            memcpy( ssl->out_iv + ssl->out_msglen, mac,
+                    ssl->transform_out->maclen );
+
             ssl->out_msglen += ssl->transform_out->maclen;
             auth_done++;
         }
@@ -2644,7 +2746,7 @@ int mbedtls_ssl_fetch_input( mbedtls_ssl_context *ssl, size_t nb_want )
 int mbedtls_ssl_flush_output( mbedtls_ssl_context *ssl )
 {
     int ret;
-    unsigned char *buf, i;
+    unsigned char *buf;
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> flush output" ) );
 
@@ -2667,8 +2769,7 @@ int mbedtls_ssl_flush_output( mbedtls_ssl_context *ssl )
         MBEDTLS_SSL_DEBUG_MSG( 2, ( "message length: %d, out_left: %d",
                        mbedtls_ssl_hdr_len( ssl ) + ssl->out_msglen, ssl->out_left ) );
 
-        buf = ssl->out_hdr + mbedtls_ssl_hdr_len( ssl ) +
-              ssl->out_msglen - ssl->out_left;
+        buf = ssl->out_hdr - ssl->out_left;
         ret = ssl->f_send( ssl->p_bio, buf, ssl->out_left );
 
         MBEDTLS_SSL_DEBUG_RET( 2, "ssl->f_send", ret );
@@ -2687,16 +2788,17 @@ int mbedtls_ssl_flush_output( mbedtls_ssl_context *ssl )
         ssl->out_left -= ret;
     }
 
-    for( i = 8; i > ssl_ep_len( ssl ); i-- )
-        if( ++ssl->out_ctr[i - 1] != 0 )
-            break;
-
-    /* The loop goes to its end iff the counter is wrapping */
-    if( i == ssl_ep_len( ssl ) )
+#if defined(MBEDTLS_SSL_PROTO_DTLS)
+    if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
+    {
+        ssl->out_hdr = ssl->out_buf;
+    }
+    else
+#endif
     {
-        MBEDTLS_SSL_DEBUG_MSG( 1, ( "outgoing message counter would wrap" ) );
-        return( MBEDTLS_ERR_SSL_COUNTER_WRAPPING );
+        ssl->out_hdr = ssl->out_buf + 8;
     }
+    ssl_update_out_pointers( ssl, ssl->transform_out );
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= flush output" ) );
 
@@ -2713,6 +2815,9 @@ int mbedtls_ssl_flush_output( mbedtls_ssl_context *ssl )
 static int ssl_flight_append( mbedtls_ssl_context *ssl )
 {
     mbedtls_ssl_flight_item *msg;
+    MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> ssl_flight_append" ) );
+    MBEDTLS_SSL_DEBUG_BUF( 4, "message appended to flight",
+                           ssl->out_msg, ssl->out_msglen );
 
     /* Allocate space for current message */
     if( ( msg = mbedtls_calloc( 1, sizeof(  mbedtls_ssl_flight_item ) ) ) == NULL )
@@ -2746,6 +2851,7 @@ static int ssl_flight_append( mbedtls_ssl_context *ssl )
         cur->next = msg;
     }
 
+    MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= ssl_flight_append" ) );
     return( 0 );
 }
 
@@ -2794,19 +2900,12 @@ static void ssl_swap_epochs( mbedtls_ssl_context *ssl )
     ssl->handshake->alt_transform_out = tmp_transform;
 
     /* Swap epoch + sequence_number */
-    memcpy( tmp_out_ctr,                 ssl->out_ctr,                8 );
-    memcpy( ssl->out_ctr,                ssl->handshake->alt_out_ctr, 8 );
+    memcpy( tmp_out_ctr,                 ssl->cur_out_ctr,            8 );
+    memcpy( ssl->cur_out_ctr,            ssl->handshake->alt_out_ctr, 8 );
     memcpy( ssl->handshake->alt_out_ctr, tmp_out_ctr,                 8 );
 
     /* Adjust to the newly activated transform */
-    if( ssl->transform_out != NULL &&
-        ssl->minor_ver >= MBEDTLS_SSL_MINOR_VERSION_2 )
-    {
-        ssl->out_msg = ssl->out_iv + ssl->transform_out->ivlen -
-                                     ssl->transform_out->fixed_ivlen;
-    }
-    else
-        ssl->out_msg = ssl->out_iv;
+    ssl_update_out_pointers( ssl, ssl->transform_out );
 
 #if defined(MBEDTLS_SSL_HW_RECORD_ACCEL)
     if( mbedtls_ssl_hw_record_activate != NULL )
@@ -2822,20 +2921,38 @@ static void ssl_swap_epochs( mbedtls_ssl_context *ssl )
 
 /*
  * Retransmit the current flight of messages.
+ */
+int mbedtls_ssl_resend( mbedtls_ssl_context *ssl )
+{
+    int ret = 0;
+
+    MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> mbedtls_ssl_resend" ) );
+
+    ret = mbedtls_ssl_flight_transmit( ssl );
+
+    MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= mbedtls_ssl_resend" ) );
+
+    return( ret );
+}
+
+/*
+ * Transmit or retransmit the current flight of messages.
  *
  * Need to remember the current message in case flush_output returns
  * WANT_WRITE, causing us to exit this function and come back later.
  * This function must be called until state is no longer SENDING.
  */
-int mbedtls_ssl_resend( mbedtls_ssl_context *ssl )
+int mbedtls_ssl_flight_transmit( mbedtls_ssl_context *ssl )
 {
-    MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> mbedtls_ssl_resend" ) );
+    int ret;
+    MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> mbedtls_ssl_flight_transmit" ) );
 
     if( ssl->handshake->retransmit_state != MBEDTLS_SSL_RETRANS_SENDING )
     {
-        MBEDTLS_SSL_DEBUG_MSG( 2, ( "initialise resending" ) );
+        MBEDTLS_SSL_DEBUG_MSG( 2, ( "initialise flight transmission" ) );
 
         ssl->handshake->cur_msg = ssl->handshake->flight;
+        ssl->handshake->cur_msg_p = ssl->handshake->flight->p + 12;
         ssl_swap_epochs( ssl );
 
         ssl->handshake->retransmit_state = MBEDTLS_SSL_RETRANS_SENDING;
@@ -2843,33 +2960,129 @@ int mbedtls_ssl_resend( mbedtls_ssl_context *ssl )
 
     while( ssl->handshake->cur_msg != NULL )
     {
-        int ret;
-        mbedtls_ssl_flight_item *cur = ssl->handshake->cur_msg;
+        size_t max_frag_len;
+        const mbedtls_ssl_flight_item * const cur = ssl->handshake->cur_msg;
+
+        int const is_finished =
+            ( cur->type == MBEDTLS_SSL_MSG_HANDSHAKE &&
+              cur->p[0] == MBEDTLS_SSL_HS_FINISHED );
+
+        uint8_t const force_flush = ssl->disable_datagram_packing == 1 ?
+            SSL_FORCE_FLUSH : SSL_DONT_FORCE_FLUSH;
 
         /* Swap epochs before sending Finished: we can't do it after
          * sending ChangeCipherSpec, in case write returns WANT_READ.
          * Must be done before copying, may change out_msg pointer */
-        if( cur->type == MBEDTLS_SSL_MSG_HANDSHAKE &&
-            cur->p[0] == MBEDTLS_SSL_HS_FINISHED )
+        if( is_finished && ssl->handshake->cur_msg_p == ( cur->p + 12 ) )
         {
+            MBEDTLS_SSL_DEBUG_MSG( 2, ( "swap epochs to send finished message" ) );
             ssl_swap_epochs( ssl );
         }
 
-        memcpy( ssl->out_msg, cur->p, cur->len );
-        ssl->out_msglen = cur->len;
-        ssl->out_msgtype = cur->type;
+        ret = ssl_get_remaining_payload_in_datagram( ssl );
+        if( ret < 0 )
+            return( ret );
+        max_frag_len = (size_t) ret;
+
+        /* CCS is copied as is, while HS messages may need fragmentation */
+        if( cur->type == MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC )
+        {
+            if( max_frag_len == 0 )
+            {
+                if( ( ret = mbedtls_ssl_flush_output( ssl ) ) != 0 )
+                    return( ret );
+
+                continue;
+            }
+
+            memcpy( ssl->out_msg, cur->p, cur->len );
+            ssl->out_msglen  = cur->len;
+            ssl->out_msgtype = cur->type;
+
+            /* Update position inside current message */
+            ssl->handshake->cur_msg_p += cur->len;
+        }
+        else
+        {
+            const unsigned char * const p = ssl->handshake->cur_msg_p;
+            const size_t hs_len = cur->len - 12;
+            const size_t frag_off = p - ( cur->p + 12 );
+            const size_t rem_len = hs_len - frag_off;
+            size_t cur_hs_frag_len, max_hs_frag_len;
+
+            if( ( max_frag_len < 12 ) || ( max_frag_len == 12 && hs_len != 0 ) )
+            {
+                if( is_finished )
+                    ssl_swap_epochs( ssl );
+
+                if( ( ret = mbedtls_ssl_flush_output( ssl ) ) != 0 )
+                    return( ret );
+
+                continue;
+            }
+            max_hs_frag_len = max_frag_len - 12;
+
+            cur_hs_frag_len = rem_len > max_hs_frag_len ?
+                max_hs_frag_len : rem_len;
+
+            if( frag_off == 0 && cur_hs_frag_len != hs_len )
+            {
+                MBEDTLS_SSL_DEBUG_MSG( 2, ( "fragmenting handshake message (%u > %u)",
+                                            (unsigned) cur_hs_frag_len,
+                                            (unsigned) max_hs_frag_len ) );
+            }
+
+            /* Messages are stored with handshake headers as if not fragmented,
+             * copy beginning of headers then fill fragmentation fields.
+             * Handshake headers: type(1) len(3) seq(2) f_off(3) f_len(3) */
+            memcpy( ssl->out_msg, cur->p, 6 );
+
+            ssl->out_msg[6] = ( ( frag_off >> 16 ) & 0xff );
+            ssl->out_msg[7] = ( ( frag_off >>  8 ) & 0xff );
+            ssl->out_msg[8] = ( ( frag_off       ) & 0xff );
+
+            ssl->out_msg[ 9] = ( ( cur_hs_frag_len >> 16 ) & 0xff );
+            ssl->out_msg[10] = ( ( cur_hs_frag_len >>  8 ) & 0xff );
+            ssl->out_msg[11] = ( ( cur_hs_frag_len       ) & 0xff );
+
+            MBEDTLS_SSL_DEBUG_BUF( 3, "handshake header", ssl->out_msg, 12 );
 
-        ssl->handshake->cur_msg = cur->next;
+            /* Copy the handshake message content and set records fields */
+            memcpy( ssl->out_msg + 12, p, cur_hs_frag_len );
+            ssl->out_msglen = cur_hs_frag_len + 12;
+            ssl->out_msgtype = cur->type;
 
-        MBEDTLS_SSL_DEBUG_BUF( 3, "resent handshake message header", ssl->out_msg, 12 );
+            /* Update position inside current message */
+            ssl->handshake->cur_msg_p += cur_hs_frag_len;
+        }
+
+        /* If done with the current message move to the next one if any */
+        if( ssl->handshake->cur_msg_p >= cur->p + cur->len )
+        {
+            if( cur->next != NULL )
+            {
+                ssl->handshake->cur_msg = cur->next;
+                ssl->handshake->cur_msg_p = cur->next->p + 12;
+            }
+            else
+            {
+                ssl->handshake->cur_msg = NULL;
+                ssl->handshake->cur_msg_p = NULL;
+            }
+        }
 
-        if( ( ret = mbedtls_ssl_write_record( ssl ) ) != 0 )
+        /* Actually send the message out */
+        if( ( ret = mbedtls_ssl_write_record( ssl, force_flush ) ) != 0 )
         {
             MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_record", ret );
             return( ret );
         }
     }
 
+    if( ( ret = mbedtls_ssl_flush_output( ssl ) ) != 0 )
+        return( ret );
+
+    /* Update state and set timer */
     if( ssl->state == MBEDTLS_SSL_HANDSHAKE_OVER )
         ssl->handshake->retransmit_state = MBEDTLS_SSL_RETRANS_FINISHED;
     else
@@ -2878,7 +3091,7 @@ int mbedtls_ssl_resend( mbedtls_ssl_context *ssl )
         ssl_set_timer( ssl, ssl->handshake->retransmit_timeout );
     }
 
-    MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= mbedtls_ssl_resend" ) );
+    MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= mbedtls_ssl_flight_transmit" ) );
 
     return( 0 );
 }
@@ -2896,6 +3109,12 @@ void mbedtls_ssl_recv_flight_completed( mbedtls_ssl_context *ssl )
     /* The next incoming flight will start with this msg_seq */
     ssl->handshake->in_flight_start_seq = ssl->handshake->in_msg_seq;
 
+    /* We don't want to remember CCS's across flight boundaries. */
+    ssl->handshake->buffering.seen_ccs = 0;
+
+    /* Clear future message buffering structure. */
+    ssl_buffering_free( ssl );
+
     /* Cancel timer */
     ssl_set_timer( ssl, 0 );
 
@@ -2927,43 +3146,100 @@ void mbedtls_ssl_send_flight_completed( mbedtls_ssl_context *ssl )
 #endif /* MBEDTLS_SSL_PROTO_DTLS */
 
 /*
- * Record layer functions
+ * Handshake layer functions
  */
 
 /*
- * Write current record.
- * Uses ssl->out_msgtype, ssl->out_msglen and bytes at ssl->out_msg.
+ * Write (DTLS: or queue) current handshake (including CCS) message.
+ *
+ *  - fill in handshake headers
+ *  - update handshake checksum
+ *  - DTLS: save message for resending
+ *  - then pass to the record layer
+ *
+ * DTLS: except for HelloRequest, messages are only queued, and will only be
+ * actually sent when calling flight_transmit() or resend().
+ *
+ * Inputs:
+ *  - ssl->out_msglen: 4 + actual handshake message len
+ *      (4 is the size of handshake headers for TLS)
+ *  - ssl->out_msg[0]: the handshake type (ClientHello, ServerHello, etc)
+ *  - ssl->out_msg + 4: the handshake message body
+ *
+ * Outputs, ie state before passing to flight_append() or write_record():
+ *   - ssl->out_msglen: the length of the record contents
+ *      (including handshake headers but excluding record headers)
+ *   - ssl->out_msg: the record contents (handshake headers + content)
  */
-int mbedtls_ssl_write_record( mbedtls_ssl_context *ssl )
+int mbedtls_ssl_write_handshake_msg( mbedtls_ssl_context *ssl )
 {
-    int ret, done = 0, out_msg_type;
-    size_t len = ssl->out_msglen;
+    int ret;
+    const size_t hs_len = ssl->out_msglen - 4;
+    const unsigned char hs_type = ssl->out_msg[0];
 
-    MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write record" ) );
+    MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write handshake message" ) );
+
+    /*
+     * Sanity checks
+     */
+    if( ssl->out_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE          &&
+        ssl->out_msgtype != MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC )
+    {
+        /* In SSLv3, the client might send a NoCertificate alert. */
+#if defined(MBEDTLS_SSL_PROTO_SSL3) && defined(MBEDTLS_SSL_CLI_C)
+        if( ! ( ssl->minor_ver      == MBEDTLS_SSL_MINOR_VERSION_0 &&
+                ssl->out_msgtype    == MBEDTLS_SSL_MSG_ALERT       &&
+                ssl->conf->endpoint == MBEDTLS_SSL_IS_CLIENT ) )
+#endif /* MBEDTLS_SSL_PROTO_SSL3 && MBEDTLS_SSL_SRV_C */
+        {
+            MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
+            return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
+        }
+    }
+
+    if( ssl->out_msgtype == MBEDTLS_SSL_MSG_HANDSHAKE &&
+        hs_type != MBEDTLS_SSL_HS_HELLO_REQUEST &&
+        ssl->handshake == NULL )
+    {
+        MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
+        return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
+    }
 
 #if defined(MBEDTLS_SSL_PROTO_DTLS)
     if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
         ssl->handshake != NULL &&
         ssl->handshake->retransmit_state == MBEDTLS_SSL_RETRANS_SENDING )
     {
-        ; /* Skip special handshake treatment when resending */
+        MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
+        return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
     }
-    else
 #endif
-    if( ssl->out_msgtype == MBEDTLS_SSL_MSG_HANDSHAKE )
-    {
-        out_msg_type = ssl->out_msg[0];
 
-        if( out_msg_type != MBEDTLS_SSL_HS_HELLO_REQUEST &&
-            ssl->handshake == NULL )
-        {
-            MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
-            return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
-        }
+    /* Double-check that we did not exceed the bounds
+     * of the outgoing record buffer.
+     * This should never fail as the various message
+     * writing functions must obey the bounds of the
+     * outgoing record buffer, but better be safe.
+     *
+     * Note: We deliberately do not check for the MTU or MFL here.
+     */
+    if( ssl->out_msglen > MBEDTLS_SSL_OUT_CONTENT_LEN )
+    {
+        MBEDTLS_SSL_DEBUG_MSG( 1, ( "Record too large: "
+                                    "size %u, maximum %u",
+                                    (unsigned) ssl->out_msglen,
+                                    (unsigned) MBEDTLS_SSL_OUT_CONTENT_LEN ) );
+        return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
+    }
 
-        ssl->out_msg[1] = (unsigned char)( ( len - 4 ) >> 16 );
-        ssl->out_msg[2] = (unsigned char)( ( len - 4 ) >>  8 );
-        ssl->out_msg[3] = (unsigned char)( ( len - 4 )       );
+    /*
+     * Fill handshake headers
+     */
+    if( ssl->out_msgtype == MBEDTLS_SSL_MSG_HANDSHAKE )
+    {
+        ssl->out_msg[1] = (unsigned char)( hs_len >> 16 );
+        ssl->out_msg[2] = (unsigned char)( hs_len >>  8 );
+        ssl->out_msg[3] = (unsigned char)( hs_len       );
 
         /*
          * DTLS has additional fields in the Handshake layer,
@@ -2980,17 +3256,16 @@ int mbedtls_ssl_write_record( mbedtls_ssl_context *ssl )
             {
                 MBEDTLS_SSL_DEBUG_MSG( 1, ( "DTLS handshake message too large: "
                               "size %u, maximum %u",
-                               (unsigned) ( ssl->in_hslen - 4 ),
+                               (unsigned) ( hs_len ),
                                (unsigned) ( MBEDTLS_SSL_OUT_CONTENT_LEN - 12 ) ) );
                 return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
             }
 
-            memmove( ssl->out_msg + 12, ssl->out_msg + 4, len - 4 );
+            memmove( ssl->out_msg + 12, ssl->out_msg + 4, hs_len );
             ssl->out_msglen += 8;
-            len += 8;
 
             /* Write message_seq and update it, except for HelloRequest */
-            if( out_msg_type != MBEDTLS_SSL_HS_HELLO_REQUEST )
+            if( hs_type != MBEDTLS_SSL_HS_HELLO_REQUEST )
             {
                 ssl->out_msg[4] = ( ssl->handshake->out_msg_seq >> 8 ) & 0xFF;
                 ssl->out_msg[5] = ( ssl->handshake->out_msg_seq      ) & 0xFF;
@@ -3002,23 +3277,23 @@ int mbedtls_ssl_write_record( mbedtls_ssl_context *ssl )
                 ssl->out_msg[5] = 0;
             }
 
-            /* We don't fragment, so frag_offset = 0 and frag_len = len */
+            /* Handshake hashes are computed without fragmentation,
+             * so set frag_offset = 0 and frag_len = hs_len for now */
             memset( ssl->out_msg + 6, 0x00, 3 );
             memcpy( ssl->out_msg + 9, ssl->out_msg + 1, 3 );
         }
 #endif /* MBEDTLS_SSL_PROTO_DTLS */
 
-        if( out_msg_type != MBEDTLS_SSL_HS_HELLO_REQUEST )
-            ssl->handshake->update_checksum( ssl, ssl->out_msg, len );
+        /* Update running hashes of handshake messages seen */
+        if( hs_type != MBEDTLS_SSL_HS_HELLO_REQUEST )
+            ssl->handshake->update_checksum( ssl, ssl->out_msg, ssl->out_msglen );
     }
 
-    /* Save handshake and CCS messages for resending */
+    /* Either send now, or just save to be sent (and resent) later */
 #if defined(MBEDTLS_SSL_PROTO_DTLS)
     if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
-        ssl->handshake != NULL &&
-        ssl->handshake->retransmit_state != MBEDTLS_SSL_RETRANS_SENDING &&
-        ( ssl->out_msgtype == MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC ||
-          ssl->out_msgtype == MBEDTLS_SSL_MSG_HANDSHAKE ) )
+        ( ssl->out_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE ||
+          hs_type != MBEDTLS_SSL_HS_HELLO_REQUEST ) )
     {
         if( ( ret = ssl_flight_append( ssl ) ) != 0 )
         {
@@ -3026,7 +3301,40 @@ int mbedtls_ssl_write_record( mbedtls_ssl_context *ssl )
             return( ret );
         }
     }
+    else
 #endif
+    {
+        if( ( ret = mbedtls_ssl_write_record( ssl, SSL_FORCE_FLUSH ) ) != 0 )
+        {
+            MBEDTLS_SSL_DEBUG_RET( 1, "ssl_write_record", ret );
+            return( ret );
+        }
+    }
+
+    MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write handshake message" ) );
+
+    return( 0 );
+}
+
+/*
+ * Record layer functions
+ */
+
+/*
+ * Write current record.
+ *
+ * Uses:
+ *  - ssl->out_msgtype: type of the message (AppData, Handshake, Alert, CCS)
+ *  - ssl->out_msglen: length of the record content (excl headers)
+ *  - ssl->out_msg: record content
+ */
+int mbedtls_ssl_write_record( mbedtls_ssl_context *ssl, uint8_t force_flush )
+{
+    int ret, done = 0;
+    size_t len = ssl->out_msglen;
+    uint8_t flush = force_flush;
+
+    MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write record" ) );
 
 #if defined(MBEDTLS_ZLIB_SUPPORT)
     if( ssl->transform_out != NULL &&
@@ -3060,10 +3368,14 @@ int mbedtls_ssl_write_record( mbedtls_ssl_context *ssl )
 #endif /* MBEDTLS_SSL_HW_RECORD_ACCEL */
     if( !done )
     {
+        unsigned i;
+        size_t protected_record_size;
+
         ssl->out_hdr[0] = (unsigned char) ssl->out_msgtype;
         mbedtls_ssl_write_version( ssl->major_ver, ssl->minor_ver,
                            ssl->conf->transport, ssl->out_hdr + 1 );
 
+        memcpy( ssl->out_ctr, ssl->cur_out_ctr, 8 );
         ssl->out_len[0] = (unsigned char)( len >> 8 );
         ssl->out_len[1] = (unsigned char)( len      );
 
@@ -3080,18 +3392,76 @@ int mbedtls_ssl_write_record( mbedtls_ssl_context *ssl )
             ssl->out_len[1] = (unsigned char)( len      );
         }
 
-        ssl->out_left = mbedtls_ssl_hdr_len( ssl ) + ssl->out_msglen;
+        protected_record_size = len + mbedtls_ssl_hdr_len( ssl );
+
+#if defined(MBEDTLS_SSL_PROTO_DTLS)
+        /* In case of DTLS, double-check that we don't exceed
+         * the remaining space in the datagram. */
+        if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
+        {
+            ret = ssl_get_remaining_space_in_datagram( ssl );
+            if( ret < 0 )
+                return( ret );
+
+            if( protected_record_size > (size_t) ret )
+            {
+                /* Should never happen */
+                return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
+            }
+        }
+#endif /* MBEDTLS_SSL_PROTO_DTLS */
 
         MBEDTLS_SSL_DEBUG_MSG( 3, ( "output record: msgtype = %d, "
-                            "version = [%d:%d], msglen = %d",
-                       ssl->out_hdr[0], ssl->out_hdr[1], ssl->out_hdr[2],
-                     ( ssl->out_len[0] << 8 ) | ssl->out_len[1] ) );
+                                    "version = [%d:%d], msglen = %d",
+                                    ssl->out_hdr[0], ssl->out_hdr[1],
+                                    ssl->out_hdr[2], len ) );
 
         MBEDTLS_SSL_DEBUG_BUF( 4, "output record sent to network",
-                       ssl->out_hdr, mbedtls_ssl_hdr_len( ssl ) + ssl->out_msglen );
+                               ssl->out_hdr, protected_record_size );
+
+        ssl->out_left += protected_record_size;
+        ssl->out_hdr  += protected_record_size;
+        ssl_update_out_pointers( ssl, ssl->transform_out );
+
+        for( i = 8; i > ssl_ep_len( ssl ); i-- )
+            if( ++ssl->cur_out_ctr[i - 1] != 0 )
+                break;
+
+        /* The loop goes to its end iff the counter is wrapping */
+        if( i == ssl_ep_len( ssl ) )
+        {
+            MBEDTLS_SSL_DEBUG_MSG( 1, ( "outgoing message counter would wrap" ) );
+            return( MBEDTLS_ERR_SSL_COUNTER_WRAPPING );
+        }
     }
 
-    if( ( ret = mbedtls_ssl_flush_output( ssl ) ) != 0 )
+#if defined(MBEDTLS_SSL_PROTO_DTLS)
+    if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
+        flush == SSL_DONT_FORCE_FLUSH )
+    {
+        size_t remaining;
+        ret = ssl_get_remaining_payload_in_datagram( ssl );
+        if( ret < 0 )
+        {
+            MBEDTLS_SSL_DEBUG_RET( 1, "ssl_get_remaining_payload_in_datagram",
+                                   ret );
+            return( ret );
+        }
+
+        remaining = (size_t) ret;
+        if( remaining == 0 )
+        {
+            flush = SSL_FORCE_FLUSH;
+        }
+        else
+        {
+            MBEDTLS_SSL_DEBUG_MSG( 2, ( "Still %u bytes available in current datagram", (unsigned) remaining ) );
+        }
+    }
+#endif /* MBEDTLS_SSL_PROTO_DTLS */
+
+    if( ( flush == SSL_FORCE_FLUSH ) &&
+        ( ret = mbedtls_ssl_flush_output( ssl ) ) != 0 )
     {
         MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_flush_output", ret );
         return( ret );
@@ -3103,23 +3473,69 @@ int mbedtls_ssl_write_record( mbedtls_ssl_context *ssl )
 }
 
 #if defined(MBEDTLS_SSL_PROTO_DTLS)
-/*
- * Mark bits in bitmask (used for DTLS HS reassembly)
- */
-static void ssl_bitmask_set( unsigned char *mask, size_t offset, size_t len )
-{
-    unsigned int start_bits, end_bits;
 
-    start_bits = 8 - ( offset % 8 );
-    if( start_bits != 8 )
+static int ssl_hs_is_proper_fragment( mbedtls_ssl_context *ssl )
+{
+    if( ssl->in_msglen < ssl->in_hslen ||
+        memcmp( ssl->in_msg + 6, "\0\0\0",        3 ) != 0 ||
+        memcmp( ssl->in_msg + 9, ssl->in_msg + 1, 3 ) != 0 )
     {
-        size_t first_byte_idx = offset / 8;
+        return( 1 );
+    }
+    return( 0 );
+}
 
-        /* Special case */
-        if( len <= start_bits )
-        {
-            for( ; len != 0; len-- )
-                mask[first_byte_idx] |= 1 << ( start_bits - len );
+static uint32_t ssl_get_hs_frag_len( mbedtls_ssl_context const *ssl )
+{
+    return( ( ssl->in_msg[9] << 16  ) |
+            ( ssl->in_msg[10] << 8  ) |
+              ssl->in_msg[11] );
+}
+
+static uint32_t ssl_get_hs_frag_off( mbedtls_ssl_context const *ssl )
+{
+    return( ( ssl->in_msg[6] << 16 ) |
+            ( ssl->in_msg[7] << 8  ) |
+              ssl->in_msg[8] );
+}
+
+static int ssl_check_hs_header( mbedtls_ssl_context const *ssl )
+{
+    uint32_t msg_len, frag_off, frag_len;
+
+    msg_len  = ssl_get_hs_total_len( ssl );
+    frag_off = ssl_get_hs_frag_off( ssl );
+    frag_len = ssl_get_hs_frag_len( ssl );
+
+    if( frag_off > msg_len )
+        return( -1 );
+
+    if( frag_len > msg_len - frag_off )
+        return( -1 );
+
+    if( frag_len + 12 > ssl->in_msglen )
+        return( -1 );
+
+    return( 0 );
+}
+
+/*
+ * Mark bits in bitmask (used for DTLS HS reassembly)
+ */
+static void ssl_bitmask_set( unsigned char *mask, size_t offset, size_t len )
+{
+    unsigned int start_bits, end_bits;
+
+    start_bits = 8 - ( offset % 8 );
+    if( start_bits != 8 )
+    {
+        size_t first_byte_idx = offset / 8;
+
+        /* Special case */
+        if( len <= start_bits )
+        {
+            for( ; len != 0; len-- )
+                mask[first_byte_idx] |= 1 << ( start_bits - len );
 
             /* Avoid potential issues with offset or len becoming invalid */
             return;
@@ -3164,161 +3580,29 @@ static int ssl_bitmask_check( unsigned char *mask, size_t len )
     return( 0 );
 }
 
-/*
- * Reassemble fragmented DTLS handshake messages.
- *
- * Use a temporary buffer for reassembly, divided in two parts:
- * - the first holds the reassembled message (including handshake header),
- * - the second holds a bitmask indicating which parts of the message
- *   (excluding headers) have been received so far.
- */
-static int ssl_reassemble_dtls_handshake( mbedtls_ssl_context *ssl )
+/* msg_len does not include the handshake header */
+static size_t ssl_get_reassembly_buffer_size( size_t msg_len,
+                                              unsigned add_bitmap )
 {
-    unsigned char *msg, *bitmask;
-    size_t frag_len, frag_off;
-    size_t msg_len = ssl->in_hslen - 12; /* Without headers */
-
-    if( ssl->handshake == NULL )
-    {
-        MBEDTLS_SSL_DEBUG_MSG( 1, ( "not supported outside handshake (for now)" ) );
-        return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
-    }
-
-    /*
-     * For first fragment, check size and allocate buffer
-     */
-    if( ssl->handshake->hs_msg == NULL )
-    {
-        size_t alloc_len;
-
-        MBEDTLS_SSL_DEBUG_MSG( 2, ( "initialize reassembly, total length = %d",
-                            msg_len ) );
+    size_t alloc_len;
 
-        if( ssl->in_hslen > MBEDTLS_SSL_IN_CONTENT_LEN )
-        {
-            MBEDTLS_SSL_DEBUG_MSG( 1, ( "handshake message too large" ) );
-            return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
-        }
-
-        /* The bitmask needs one bit per byte of message excluding header */
-        alloc_len = 12 + msg_len + msg_len / 8 + ( msg_len % 8 != 0 );
-
-        ssl->handshake->hs_msg = mbedtls_calloc( 1, alloc_len );
-        if( ssl->handshake->hs_msg == NULL )
-        {
-            MBEDTLS_SSL_DEBUG_MSG( 1, ( "alloc failed (%d bytes)", alloc_len ) );
-            return( MBEDTLS_ERR_SSL_ALLOC_FAILED );
-        }
-
-        /* Prepare final header: copy msg_type, length and message_seq,
-         * then add standardised fragment_offset and fragment_length */
-        memcpy( ssl->handshake->hs_msg, ssl->in_msg, 6 );
-        memset( ssl->handshake->hs_msg + 6, 0, 3 );
-        memcpy( ssl->handshake->hs_msg + 9,
-                ssl->handshake->hs_msg + 1, 3 );
-    }
-    else
-    {
-        /* Make sure msg_type and length are consistent */
-        if( memcmp( ssl->handshake->hs_msg, ssl->in_msg, 4 ) != 0 )
-        {
-            MBEDTLS_SSL_DEBUG_MSG( 1, ( "fragment header mismatch" ) );
-            return( MBEDTLS_ERR_SSL_INVALID_RECORD );
-        }
-    }
-
-    msg = ssl->handshake->hs_msg + 12;
-    bitmask = msg + msg_len;
-
-    /*
-     * Check and copy current fragment
-     */
-    frag_off = ( ssl->in_msg[6]  << 16 ) |
-               ( ssl->in_msg[7]  << 8  ) |
-                 ssl->in_msg[8];
-    frag_len = ( ssl->in_msg[9]  << 16 ) |
-               ( ssl->in_msg[10] << 8  ) |
-                 ssl->in_msg[11];
-
-    if( frag_off + frag_len > msg_len )
-    {
-        MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid fragment offset/len: %d + %d > %d",
-                          frag_off, frag_len, msg_len ) );
-        return( MBEDTLS_ERR_SSL_INVALID_RECORD );
-    }
-
-    if( frag_len + 12 > ssl->in_msglen )
-    {
-        MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid fragment length: %d + 12 > %d",
-                          frag_len, ssl->in_msglen ) );
-        return( MBEDTLS_ERR_SSL_INVALID_RECORD );
-    }
-
-    MBEDTLS_SSL_DEBUG_MSG( 2, ( "adding fragment, offset = %d, length = %d",
-                        frag_off, frag_len ) );
-
-    memcpy( msg + frag_off, ssl->in_msg + 12, frag_len );
-    ssl_bitmask_set( bitmask, frag_off, frag_len );
-
-    /*
-     * Do we have the complete message by now?
-     * If yes, finalize it, else ask to read the next record.
-     */
-    if( ssl_bitmask_check( bitmask, msg_len ) != 0 )
-    {
-        MBEDTLS_SSL_DEBUG_MSG( 2, ( "message is not complete yet" ) );
-        return( MBEDTLS_ERR_SSL_CONTINUE_PROCESSING );
-    }
-
-    MBEDTLS_SSL_DEBUG_MSG( 2, ( "handshake message completed" ) );
-
-    if( frag_len + 12 < ssl->in_msglen )
-    {
-        /*
-         * We'got more handshake messages in the same record.
-         * This case is not handled now because no know implementation does
-         * that and it's hard to test, so we prefer to fail cleanly for now.
-         */
-        MBEDTLS_SSL_DEBUG_MSG( 1, ( "last fragment not alone in its record" ) );
-        return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
-    }
-
-    if( ssl->in_left > ssl->next_record_offset )
-    {
-        /*
-         * We've got more data in the buffer after the current record,
-         * that we don't want to overwrite. Move it before writing the
-         * reassembled message, and adjust in_left and next_record_offset.
-         */
-        unsigned char *cur_remain = ssl->in_hdr + ssl->next_record_offset;
-        unsigned char *new_remain = ssl->in_msg + ssl->in_hslen;
-        size_t remain_len = ssl->in_left - ssl->next_record_offset;
+    alloc_len  = 12;                                 /* Handshake header */
+    alloc_len += msg_len;                            /* Content buffer   */
 
-        /* First compute and check new lengths */
-        ssl->next_record_offset = new_remain - ssl->in_hdr;
-        ssl->in_left = ssl->next_record_offset + remain_len;
+    if( add_bitmap )
+        alloc_len += msg_len / 8 + ( msg_len % 8 != 0 ); /* Bitmap       */
 
-        if( ssl->in_left > MBEDTLS_SSL_IN_BUFFER_LEN -
-                           (size_t)( ssl->in_hdr - ssl->in_buf ) )
-        {
-            MBEDTLS_SSL_DEBUG_MSG( 1, ( "reassembled message too large for buffer" ) );
-            return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL );
-        }
-
-        memmove( new_remain, cur_remain, remain_len );
-    }
-
-    memcpy( ssl->in_msg, ssl->handshake->hs_msg, ssl->in_hslen );
-
-    mbedtls_free( ssl->handshake->hs_msg );
-    ssl->handshake->hs_msg = NULL;
+    return( alloc_len );
+}
 
-    MBEDTLS_SSL_DEBUG_BUF( 3, "reassembled handshake message",
-                   ssl->in_msg, ssl->in_hslen );
+#endif /* MBEDTLS_SSL_PROTO_DTLS */
 
-    return( 0 );
+static uint32_t ssl_get_hs_total_len( mbedtls_ssl_context const *ssl )
+{
+    return( ( ssl->in_msg[1] << 16 ) |
+            ( ssl->in_msg[2] << 8  ) |
+              ssl->in_msg[3] );
 }
-#endif /* MBEDTLS_SSL_PROTO_DTLS */
 
 int mbedtls_ssl_prepare_handshake_record( mbedtls_ssl_context *ssl )
 {
@@ -3329,10 +3613,7 @@ int mbedtls_ssl_prepare_handshake_record( mbedtls_ssl_context *ssl )
         return( MBEDTLS_ERR_SSL_INVALID_RECORD );
     }
 
-    ssl->in_hslen = mbedtls_ssl_hs_hdr_len( ssl ) + (
-                    ( ssl->in_msg[1] << 16 ) |
-                    ( ssl->in_msg[2] << 8  ) |
-                      ssl->in_msg[3] );
+    ssl->in_hslen = mbedtls_ssl_hs_hdr_len( ssl ) + ssl_get_hs_total_len( ssl );
 
     MBEDTLS_SSL_DEBUG_MSG( 3, ( "handshake message: msglen ="
                         " %d, type = %d, hslen = %d",
@@ -3344,12 +3625,26 @@ int mbedtls_ssl_prepare_handshake_record( mbedtls_ssl_context *ssl )
         int ret;
         unsigned int recv_msg_seq = ( ssl->in_msg[4] << 8 ) | ssl->in_msg[5];
 
+        if( ssl_check_hs_header( ssl ) != 0 )
+        {
+            MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid handshake header" ) );
+            return( MBEDTLS_ERR_SSL_INVALID_RECORD );
+        }
+
         if( ssl->handshake != NULL &&
             ( ( ssl->state   != MBEDTLS_SSL_HANDSHAKE_OVER &&
                 recv_msg_seq != ssl->handshake->in_msg_seq ) ||
               ( ssl->state  == MBEDTLS_SSL_HANDSHAKE_OVER &&
                 ssl->in_msg[0] != MBEDTLS_SSL_HS_CLIENT_HELLO ) ) )
         {
+            if( recv_msg_seq > ssl->handshake->in_msg_seq )
+            {
+                MBEDTLS_SSL_DEBUG_MSG( 2, ( "received future handshake message of sequence number %u (next %u)",
+                                            recv_msg_seq,
+                                            ssl->handshake->in_msg_seq ) );
+                return( MBEDTLS_ERR_SSL_EARLY_MESSAGE );
+            }
+
             /* Retransmit only on last message from previous flight, to avoid
              * too many retransmissions.
              * Besides, No sane server ever retransmits HelloVerifyRequest */
@@ -3379,20 +3674,14 @@ int mbedtls_ssl_prepare_handshake_record( mbedtls_ssl_context *ssl )
         }
         /* Wait until message completion to increment in_msg_seq */
 
-        /* Reassemble if current message is fragmented or reassembly is
-         * already in progress */
-        if( ssl->in_msglen < ssl->in_hslen ||
-            memcmp( ssl->in_msg + 6, "\0\0\0",        3 ) != 0 ||
-            memcmp( ssl->in_msg + 9, ssl->in_msg + 1, 3 ) != 0 ||
-            ( ssl->handshake != NULL && ssl->handshake->hs_msg != NULL ) )
+        /* Message reassembly is handled alongside buffering of future
+         * messages; the commonality is that both handshake fragments and
+         * future messages cannot be forwarded immediately to the
+         * handshake logic layer. */
+        if( ssl_hs_is_proper_fragment( ssl ) == 1 )
         {
             MBEDTLS_SSL_DEBUG_MSG( 2, ( "found fragmented DTLS handshake message" ) );
-
-            if( ( ret = ssl_reassemble_dtls_handshake( ssl ) ) != 0 )
-            {
-                MBEDTLS_SSL_DEBUG_RET( 1, "ssl_reassemble_dtls_handshake", ret );
-                return( ret );
-            }
+            return( MBEDTLS_ERR_SSL_EARLY_MESSAGE );
         }
     }
     else
@@ -3409,9 +3698,9 @@ int mbedtls_ssl_prepare_handshake_record( mbedtls_ssl_context *ssl )
 
 void mbedtls_ssl_update_handshake_status( mbedtls_ssl_context *ssl )
 {
+    mbedtls_ssl_handshake_params * const hs = ssl->handshake;
 
-    if( ssl->state != MBEDTLS_SSL_HANDSHAKE_OVER &&
-        ssl->handshake != NULL )
+    if( ssl->state != MBEDTLS_SSL_HANDSHAKE_OVER && hs != NULL )
     {
         ssl->handshake->update_checksum( ssl, ssl->in_msg, ssl->in_hslen );
     }
@@ -3421,7 +3710,29 @@ void mbedtls_ssl_update_handshake_status( mbedtls_ssl_context *ssl )
     if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
         ssl->handshake != NULL )
     {
-        ssl->handshake->in_msg_seq++;
+        unsigned offset;
+        mbedtls_ssl_hs_buffer *hs_buf;
+
+        /* Increment handshake sequence number */
+        hs->in_msg_seq++;
+
+        /*
+         * Clear up handshake buffering and reassembly structure.
+         */
+
+        /* Free first entry */
+        ssl_buffering_free_slot( ssl, 0 );
+
+        /* Shift all other entries */
+        for( offset = 0, hs_buf = &hs->buffering.hs[0];
+             offset + 1 < MBEDTLS_SSL_MAX_BUFFERED_HS;
+             offset++, hs_buf++ )
+        {
+            *hs_buf = *(hs_buf + 1);
+        }
+
+        /* Create a fresh last entry */
+        memset( hs_buf, 0, sizeof( mbedtls_ssl_hs_buffer ) );
     }
 #endif
 }
@@ -3822,7 +4133,16 @@ static int ssl_parse_record_header( mbedtls_ssl_context *ssl )
             }
             else
 #endif /* MBEDTLS_SSL_DTLS_CLIENT_PORT_REUSE && MBEDTLS_SSL_SRV_C */
+            {
+                /* Consider buffering the record. */
+                if( rec_epoch == (unsigned int) ssl->in_epoch + 1 )
+                {
+                    MBEDTLS_SSL_DEBUG_MSG( 2, ( "Consider record for buffering" ) );
+                    return( MBEDTLS_ERR_SSL_EARLY_MESSAGE );
+                }
+
                 return( MBEDTLS_ERR_SSL_UNEXPECTED_RECORD );
+            }
         }
 
 #if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY)
@@ -3835,15 +4155,6 @@ static int ssl_parse_record_header( mbedtls_ssl_context *ssl )
         }
 #endif
 
-        /* Drop unexpected ChangeCipherSpec messages */
-        if( ssl->in_msgtype == MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC &&
-            ssl->state != MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC &&
-            ssl->state != MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC )
-        {
-            MBEDTLS_SSL_DEBUG_MSG( 1, ( "dropping unexpected ChangeCipherSpec" ) );
-            return( MBEDTLS_ERR_SSL_UNEXPECTED_RECORD );
-        }
-
         /* Drop unexpected ApplicationData records,
          * except at the beginning of renegotiations */
         if( ssl->in_msgtype == MBEDTLS_SSL_MSG_APPLICATION_DATA &&
@@ -3980,7 +4291,14 @@ static void ssl_handshake_wrapup_free_hs_transform( mbedtls_ssl_context *ssl );
  * RFC 6347 4.1.2.7) and continue reading until a valid record is found.
  *
  */
-int mbedtls_ssl_read_record( mbedtls_ssl_context *ssl )
+
+/* Helper functions for mbedtls_ssl_read_record(). */
+static int ssl_consume_current_message( mbedtls_ssl_context *ssl );
+static int ssl_get_next_record( mbedtls_ssl_context *ssl );
+static int ssl_record_is_in_progress( mbedtls_ssl_context *ssl );
+
+int mbedtls_ssl_read_record( mbedtls_ssl_context *ssl,
+                             unsigned update_hs_digest )
 {
     int ret;
 
@@ -3990,17 +4308,53 @@ int mbedtls_ssl_read_record( mbedtls_ssl_context *ssl )
     {
         do {
 
-            do ret = mbedtls_ssl_read_record_layer( ssl );
-            while( ret == MBEDTLS_ERR_SSL_CONTINUE_PROCESSING );
-
+            ret = ssl_consume_current_message( ssl );
             if( ret != 0 )
-            {
-                MBEDTLS_SSL_DEBUG_RET( 1, ( "mbedtls_ssl_read_record_layer" ), ret );
                 return( ret );
+
+            if( ssl_record_is_in_progress( ssl ) == 0 )
+            {
+#if defined(MBEDTLS_SSL_PROTO_DTLS)
+                int have_buffered = 0;
+
+                /* We only check for buffered messages if the
+                 * current datagram is fully consumed. */
+                if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
+                    ssl_next_record_is_in_datagram( ssl ) == 0 )
+                {
+                    if( ssl_load_buffered_message( ssl ) == 0 )
+                        have_buffered = 1;
+                }
+
+                if( have_buffered == 0 )
+#endif /* MBEDTLS_SSL_PROTO_DTLS */
+                {
+                    ret = ssl_get_next_record( ssl );
+                    if( ret == MBEDTLS_ERR_SSL_CONTINUE_PROCESSING )
+                        continue;
+
+                    if( ret != 0 )
+                    {
+                        MBEDTLS_SSL_DEBUG_RET( 1, ( "ssl_get_next_record" ), ret );
+                        return( ret );
+                    }
+                }
             }
 
             ret = mbedtls_ssl_handle_message_type( ssl );
 
+#if defined(MBEDTLS_SSL_PROTO_DTLS)
+            if( ret == MBEDTLS_ERR_SSL_EARLY_MESSAGE )
+            {
+                /* Buffer future message */
+                ret = ssl_buffer_message( ssl );
+                if( ret != 0 )
+                    return( ret );
+
+                ret = MBEDTLS_ERR_SSL_CONTINUE_PROCESSING;
+            }
+#endif /* MBEDTLS_SSL_PROTO_DTLS */
+
         } while( MBEDTLS_ERR_SSL_NON_FATAL           == ret  ||
                  MBEDTLS_ERR_SSL_CONTINUE_PROCESSING == ret );
 
@@ -4010,14 +4364,15 @@ int mbedtls_ssl_read_record( mbedtls_ssl_context *ssl )
             return( ret );
         }
 
-        if( ssl->in_msgtype == MBEDTLS_SSL_MSG_HANDSHAKE )
+        if( ssl->in_msgtype == MBEDTLS_SSL_MSG_HANDSHAKE &&
+            update_hs_digest == 1 )
         {
             mbedtls_ssl_update_handshake_status( ssl );
         }
     }
     else
     {
-        MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= reuse previously read message" ) );
+        MBEDTLS_SSL_DEBUG_MSG( 2, ( "reuse previously read message" ) );
         ssl->keep_current_message = 0;
     }
 
@@ -4026,13 +4381,350 @@ int mbedtls_ssl_read_record( mbedtls_ssl_context *ssl )
     return( 0 );
 }
 
-int mbedtls_ssl_read_record_layer( mbedtls_ssl_context *ssl )
+#if defined(MBEDTLS_SSL_PROTO_DTLS)
+static int ssl_next_record_is_in_datagram( mbedtls_ssl_context *ssl )
 {
-    int ret;
+    if( ssl->in_left > ssl->next_record_offset )
+        return( 1 );
+
+    return( 0 );
+}
+
+static int ssl_load_buffered_message( mbedtls_ssl_context *ssl )
+{
+    mbedtls_ssl_handshake_params * const hs = ssl->handshake;
+    mbedtls_ssl_hs_buffer * hs_buf;
+    int ret = 0;
+
+    if( hs == NULL )
+        return( -1 );
+
+    MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> ssl_load_buffered_messsage" ) );
+
+    if( ssl->state == MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC ||
+        ssl->state == MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC )
+    {
+        /* Check if we have seen a ChangeCipherSpec before.
+         * If yes, synthesize a CCS record. */
+        if( !hs->buffering.seen_ccs )
+        {
+            MBEDTLS_SSL_DEBUG_MSG( 2, ( "CCS not seen in the current flight" ) );
+            ret = -1;
+            goto exit;
+        }
+
+        MBEDTLS_SSL_DEBUG_MSG( 2, ( "Injecting buffered CCS message" ) );
+        ssl->in_msgtype = MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC;
+        ssl->in_msglen = 1;
+        ssl->in_msg[0] = 1;
+
+        /* As long as they are equal, the exact value doesn't matter. */
+        ssl->in_left            = 0;
+        ssl->next_record_offset = 0;
+
+        hs->buffering.seen_ccs = 0;
+        goto exit;
+    }
 
+#if defined(MBEDTLS_DEBUG_C)
+    /* Debug only */
+    {
+        unsigned offset;
+        for( offset = 1; offset < MBEDTLS_SSL_MAX_BUFFERED_HS; offset++ )
+        {
+            hs_buf = &hs->buffering.hs[offset];
+            if( hs_buf->is_valid == 1 )
+            {
+                MBEDTLS_SSL_DEBUG_MSG( 2, ( "Future message with sequence number %u %s buffered.",
+                            hs->in_msg_seq + offset,
+                            hs_buf->is_complete ? "fully" : "partially" ) );
+            }
+        }
+    }
+#endif /* MBEDTLS_DEBUG_C */
+
+    /* Check if we have buffered and/or fully reassembled the
+     * next handshake message. */
+    hs_buf = &hs->buffering.hs[0];
+    if( ( hs_buf->is_valid == 1 ) && ( hs_buf->is_complete == 1 ) )
+    {
+        /* Synthesize a record containing the buffered HS message. */
+        size_t msg_len = ( hs_buf->data[1] << 16 ) |
+                         ( hs_buf->data[2] << 8  ) |
+                           hs_buf->data[3];
+
+        /* Double-check that we haven't accidentally buffered
+         * a message that doesn't fit into the input buffer. */
+        if( msg_len + 12 > MBEDTLS_SSL_IN_CONTENT_LEN )
+        {
+            MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
+            return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
+        }
+
+        MBEDTLS_SSL_DEBUG_MSG( 2, ( "Next handshake message has been buffered - load" ) );
+        MBEDTLS_SSL_DEBUG_BUF( 3, "Buffered handshake message (incl. header)",
+                               hs_buf->data, msg_len + 12 );
+
+        ssl->in_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
+        ssl->in_hslen   = msg_len + 12;
+        ssl->in_msglen  = msg_len + 12;
+        memcpy( ssl->in_msg, hs_buf->data, ssl->in_hslen );
+
+        ret = 0;
+        goto exit;
+    }
+    else
+    {
+        MBEDTLS_SSL_DEBUG_MSG( 2, ( "Next handshake message %u not or only partially bufffered",
+                                    hs->in_msg_seq ) );
+    }
+
+    ret = -1;
+
+exit:
+
+    MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= ssl_load_buffered_message" ) );
+    return( ret );
+}
+
+static int ssl_buffer_make_space( mbedtls_ssl_context *ssl,
+                                  size_t desired )
+{
+    int offset;
+    mbedtls_ssl_handshake_params * const hs = ssl->handshake;
+    MBEDTLS_SSL_DEBUG_MSG( 2, ( "Attempt to free buffered messages to have %u bytes available",
+                                (unsigned) desired ) );
+
+    /* Get rid of future records epoch first, if such exist. */
+    ssl_free_buffered_record( ssl );
+
+    /* Check if we have enough space available now. */
+    if( desired <= ( MBEDTLS_SSL_DTLS_MAX_BUFFERING -
+                     hs->buffering.total_bytes_buffered ) )
+    {
+        MBEDTLS_SSL_DEBUG_MSG( 2, ( "Enough space available after freeing future epoch record" ) );
+        return( 0 );
+    }
+
+    /* We don't have enough space to buffer the next expected handshake
+     * message. Remove buffers used for future messages to gain space,
+     * starting with the most distant one. */
+    for( offset = MBEDTLS_SSL_MAX_BUFFERED_HS - 1;
+         offset >= 0; offset-- )
+    {
+        MBEDTLS_SSL_DEBUG_MSG( 2, ( "Free buffering slot %d to make space for reassembly of next handshake message",
+                                    offset ) );
+
+        ssl_buffering_free_slot( ssl, (uint8_t) offset );
+
+        /* Check if we have enough space available now. */
+        if( desired <= ( MBEDTLS_SSL_DTLS_MAX_BUFFERING -
+                         hs->buffering.total_bytes_buffered ) )
+        {
+            MBEDTLS_SSL_DEBUG_MSG( 2, ( "Enough space available after freeing buffered HS messages" ) );
+            return( 0 );
+        }
+    }
+
+    return( -1 );
+}
+
+static int ssl_buffer_message( mbedtls_ssl_context *ssl )
+{
+    int ret = 0;
+    mbedtls_ssl_handshake_params * const hs = ssl->handshake;
+
+    if( hs == NULL )
+        return( 0 );
+
+    MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> ssl_buffer_message" ) );
+
+    switch( ssl->in_msgtype )
+    {
+        case MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC:
+            MBEDTLS_SSL_DEBUG_MSG( 2, ( "Remember CCS message" ) );
+
+            hs->buffering.seen_ccs = 1;
+            break;
+
+        case MBEDTLS_SSL_MSG_HANDSHAKE:
+        {
+            unsigned recv_msg_seq_offset;
+            unsigned recv_msg_seq = ( ssl->in_msg[4] << 8 ) | ssl->in_msg[5];
+            mbedtls_ssl_hs_buffer *hs_buf;
+            size_t msg_len = ssl->in_hslen - 12;
+
+            /* We should never receive an old handshake
+             * message - double-check nonetheless. */
+            if( recv_msg_seq < ssl->handshake->in_msg_seq )
+            {
+                MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
+                return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
+            }
+
+            recv_msg_seq_offset = recv_msg_seq - ssl->handshake->in_msg_seq;
+            if( recv_msg_seq_offset >= MBEDTLS_SSL_MAX_BUFFERED_HS )
+            {
+                /* Silently ignore -- message too far in the future */
+                MBEDTLS_SSL_DEBUG_MSG( 2,
+                 ( "Ignore future HS message with sequence number %u, "
+                   "buffering window %u - %u",
+                   recv_msg_seq, ssl->handshake->in_msg_seq,
+                   ssl->handshake->in_msg_seq + MBEDTLS_SSL_MAX_BUFFERED_HS - 1 ) );
+
+                goto exit;
+            }
+
+            MBEDTLS_SSL_DEBUG_MSG( 2, ( "Buffering HS message with sequence number %u, offset %u ",
+                                        recv_msg_seq, recv_msg_seq_offset ) );
+
+            hs_buf = &hs->buffering.hs[ recv_msg_seq_offset ];
+
+            /* Check if the buffering for this seq nr has already commenced. */
+            if( !hs_buf->is_valid )
+            {
+                size_t reassembly_buf_sz;
+
+                hs_buf->is_fragmented =
+                    ( ssl_hs_is_proper_fragment( ssl ) == 1 );
+
+                /* We copy the message back into the input buffer
+                 * after reassembly, so check that it's not too large.
+                 * This is an implementation-specific limitation
+                 * and not one from the standard, hence it is not
+                 * checked in ssl_check_hs_header(). */
+                if( msg_len + 12 > MBEDTLS_SSL_IN_CONTENT_LEN )
+                {
+                    /* Ignore message */
+                    goto exit;
+                }
+
+                /* Check if we have enough space to buffer the message. */
+                if( hs->buffering.total_bytes_buffered >
+                    MBEDTLS_SSL_DTLS_MAX_BUFFERING )
+                {
+                    MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
+                    return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
+                }
+
+                reassembly_buf_sz = ssl_get_reassembly_buffer_size( msg_len,
+                                                       hs_buf->is_fragmented );
+
+                if( reassembly_buf_sz > ( MBEDTLS_SSL_DTLS_MAX_BUFFERING -
+                                          hs->buffering.total_bytes_buffered ) )
+                {
+                    if( recv_msg_seq_offset > 0 )
+                    {
+                        /* If we can't buffer a future message because
+                         * of space limitations -- ignore. */
+                        MBEDTLS_SSL_DEBUG_MSG( 2, ( "Buffering of future message of size %u would exceed the compile-time limit %u (already %u bytes buffered) -- ignore\n",
+                             (unsigned) msg_len, MBEDTLS_SSL_DTLS_MAX_BUFFERING,
+                             (unsigned) hs->buffering.total_bytes_buffered ) );
+                        goto exit;
+                    }
+                    else
+                    {
+                        MBEDTLS_SSL_DEBUG_MSG( 2, ( "Buffering of future message of size %u would exceed the compile-time limit %u (already %u bytes buffered) -- attempt to make space by freeing buffered future messages\n",
+                             (unsigned) msg_len, MBEDTLS_SSL_DTLS_MAX_BUFFERING,
+                             (unsigned) hs->buffering.total_bytes_buffered ) );
+                    }
+
+                    if( ssl_buffer_make_space( ssl, reassembly_buf_sz ) != 0 )
+                    {
+                        MBEDTLS_SSL_DEBUG_MSG( 2, ( "Reassembly of next message of size %u (%u with bitmap) would exceed the compile-time limit %u (already %u bytes buffered) -- fail\n",
+                             (unsigned) msg_len,
+                             (unsigned) reassembly_buf_sz,
+                             MBEDTLS_SSL_DTLS_MAX_BUFFERING,
+                             (unsigned) hs->buffering.total_bytes_buffered ) );
+                        ret = MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL;
+                        goto exit;
+                    }
+                }
+
+                MBEDTLS_SSL_DEBUG_MSG( 2, ( "initialize reassembly, total length = %d",
+                                            msg_len ) );
+
+                hs_buf->data = mbedtls_calloc( 1, reassembly_buf_sz );
+                if( hs_buf->data == NULL )
+                {
+                    ret = MBEDTLS_ERR_SSL_ALLOC_FAILED;
+                    goto exit;
+                }
+                hs_buf->data_len = reassembly_buf_sz;
+
+                /* Prepare final header: copy msg_type, length and message_seq,
+                 * then add standardised fragment_offset and fragment_length */
+                memcpy( hs_buf->data, ssl->in_msg, 6 );
+                memset( hs_buf->data + 6, 0, 3 );
+                memcpy( hs_buf->data + 9, hs_buf->data + 1, 3 );
+
+                hs_buf->is_valid = 1;
+
+                hs->buffering.total_bytes_buffered += reassembly_buf_sz;
+            }
+            else
+            {
+                /* Make sure msg_type and length are consistent */
+                if( memcmp( hs_buf->data, ssl->in_msg, 4 ) != 0 )
+                {
+                    MBEDTLS_SSL_DEBUG_MSG( 1, ( "Fragment header mismatch - ignore" ) );
+                    /* Ignore */
+                    goto exit;
+                }
+            }
+
+            if( !hs_buf->is_complete )
+            {
+                size_t frag_len, frag_off;
+                unsigned char * const msg = hs_buf->data + 12;
+
+                /*
+                 * Check and copy current fragment
+                 */
+
+                /* Validation of header fields already done in
+                 * mbedtls_ssl_prepare_handshake_record(). */
+                frag_off = ssl_get_hs_frag_off( ssl );
+                frag_len = ssl_get_hs_frag_len( ssl );
+
+                MBEDTLS_SSL_DEBUG_MSG( 2, ( "adding fragment, offset = %d, length = %d",
+                                            frag_off, frag_len ) );
+                memcpy( msg + frag_off, ssl->in_msg + 12, frag_len );
+
+                if( hs_buf->is_fragmented )
+                {
+                    unsigned char * const bitmask = msg + msg_len;
+                    ssl_bitmask_set( bitmask, frag_off, frag_len );
+                    hs_buf->is_complete = ( ssl_bitmask_check( bitmask,
+                                                               msg_len ) == 0 );
+                }
+                else
+                {
+                    hs_buf->is_complete = 1;
+                }
+
+                MBEDTLS_SSL_DEBUG_MSG( 2, ( "message %scomplete",
+                                   hs_buf->is_complete ? "" : "not yet " ) );
+            }
+
+            break;
+        }
+
+        default:
+            /* We don't buffer other types of messages. */
+            break;
+    }
+
+exit:
+
+    MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= ssl_buffer_message" ) );
+    return( ret );
+}
+#endif /* MBEDTLS_SSL_PROTO_DTLS */
+
+static int ssl_consume_current_message( mbedtls_ssl_context *ssl )
+{
     /*
-     * Step A
-     *
      * Consume last content-layer message and potentially
      * update in_msglen which keeps track of the contents'
      * consumption state.
@@ -4114,20 +4806,161 @@ int mbedtls_ssl_read_record_layer( mbedtls_ssl_context *ssl )
         ssl->in_msglen = 0;
     }
 
-    /*
-     * Step B
-     *
-     * Fetch and decode new record if current one is fully consumed.
-     *
-     */
+    return( 0 );
+}
+
+static int ssl_record_is_in_progress( mbedtls_ssl_context *ssl )
+{
+    if( ssl->in_msglen > 0 )
+        return( 1 );
+
+    return( 0 );
+}
+
+#if defined(MBEDTLS_SSL_PROTO_DTLS)
+
+static void ssl_free_buffered_record( mbedtls_ssl_context *ssl )
+{
+    mbedtls_ssl_handshake_params * const hs = ssl->handshake;
+    if( hs == NULL )
+        return;
+
+    if( hs->buffering.future_record.data != NULL )
+    {
+        hs->buffering.total_bytes_buffered -=
+            hs->buffering.future_record.len;
+
+        mbedtls_free( hs->buffering.future_record.data );
+        hs->buffering.future_record.data = NULL;
+    }
+}
+
+static int ssl_load_buffered_record( mbedtls_ssl_context *ssl )
+{
+    mbedtls_ssl_handshake_params * const hs = ssl->handshake;
+    unsigned char * rec;
+    size_t rec_len;
+    unsigned rec_epoch;
+
+    if( ssl->conf->transport != MBEDTLS_SSL_TRANSPORT_DATAGRAM )
+        return( 0 );
+
+    if( hs == NULL )
+        return( 0 );
+
+    rec       = hs->buffering.future_record.data;
+    rec_len   = hs->buffering.future_record.len;
+    rec_epoch = hs->buffering.future_record.epoch;
+
+    if( rec == NULL )
+        return( 0 );
+
+    /* Only consider loading future records if the
+     * input buffer is empty. */
+    if( ssl_next_record_is_in_datagram( ssl ) == 1 )
+        return( 0 );
+
+    MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> ssl_load_buffered_record" ) );
+
+    if( rec_epoch != ssl->in_epoch )
+    {
+        MBEDTLS_SSL_DEBUG_MSG( 2, ( "Buffered record not from current epoch." ) );
+        goto exit;
+    }
+
+    MBEDTLS_SSL_DEBUG_MSG( 2, ( "Found buffered record from current epoch - load" ) );
+
+    /* Double-check that the record is not too large */
+    if( rec_len > MBEDTLS_SSL_IN_BUFFER_LEN -
+        (size_t)( ssl->in_hdr - ssl->in_buf ) )
+    {
+        MBEDTLS_SSL_DEBUG_MSG( 1, ( "should never happen" ) );
+        return( MBEDTLS_ERR_SSL_INTERNAL_ERROR );
+    }
+
+    memcpy( ssl->in_hdr, rec, rec_len );
+    ssl->in_left = rec_len;
+    ssl->next_record_offset = 0;
+
+    ssl_free_buffered_record( ssl );
+
+exit:
+    MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= ssl_load_buffered_record" ) );
+    return( 0 );
+}
+
+static int ssl_buffer_future_record( mbedtls_ssl_context *ssl )
+{
+    mbedtls_ssl_handshake_params * const hs = ssl->handshake;
+    size_t const rec_hdr_len = 13;
+    size_t const total_buf_sz = rec_hdr_len + ssl->in_msglen;
+
+    /* Don't buffer future records outside handshakes. */
+    if( hs == NULL )
+        return( 0 );
+
+    /* Only buffer handshake records (we are only interested
+     * in Finished messages). */
+    if( ssl->in_msgtype != MBEDTLS_SSL_MSG_HANDSHAKE )
+        return( 0 );
+
+    /* Don't buffer more than one future epoch record. */
+    if( hs->buffering.future_record.data != NULL )
+        return( 0 );
+
+    /* Don't buffer record if there's not enough buffering space remaining. */
+    if( total_buf_sz > ( MBEDTLS_SSL_DTLS_MAX_BUFFERING -
+                         hs->buffering.total_bytes_buffered ) )
+    {
+        MBEDTLS_SSL_DEBUG_MSG( 2, ( "Buffering of future epoch record of size %u would exceed the compile-time limit %u (already %u bytes buffered) -- ignore\n",
+                        (unsigned) total_buf_sz, MBEDTLS_SSL_DTLS_MAX_BUFFERING,
+                        (unsigned) hs->buffering.total_bytes_buffered ) );
+        return( 0 );
+    }
+
+    /* Buffer record */
+    MBEDTLS_SSL_DEBUG_MSG( 2, ( "Buffer record from epoch %u",
+                                ssl->in_epoch + 1 ) );
+    MBEDTLS_SSL_DEBUG_BUF( 3, "Buffered record", ssl->in_hdr,
+                           rec_hdr_len + ssl->in_msglen );
 
-    if( ssl->in_msglen > 0 )
+    /* ssl_parse_record_header() only considers records
+     * of the next epoch as candidates for buffering. */
+    hs->buffering.future_record.epoch = ssl->in_epoch + 1;
+    hs->buffering.future_record.len   = total_buf_sz;
+
+    hs->buffering.future_record.data =
+        mbedtls_calloc( 1, hs->buffering.future_record.len );
+    if( hs->buffering.future_record.data == NULL )
     {
-        /* There's something left to be processed in the current record. */
+        /* If we run out of RAM trying to buffer a
+         * record from the next epoch, just ignore. */
         return( 0 );
     }
 
-    /* Current record either fully processed or to be discarded. */
+    memcpy( hs->buffering.future_record.data, ssl->in_hdr, total_buf_sz );
+
+    hs->buffering.total_bytes_buffered += total_buf_sz;
+    return( 0 );
+}
+
+#endif /* MBEDTLS_SSL_PROTO_DTLS */
+
+static int ssl_get_next_record( mbedtls_ssl_context *ssl )
+{
+    int ret;
+
+#if defined(MBEDTLS_SSL_PROTO_DTLS)
+    /* We might have buffered a future record; if so,
+     * and if the epoch matches now, load it.
+     * On success, this call will set ssl->in_left to
+     * the length of the buffered record, so that
+     * the calls to ssl_fetch_input() below will
+     * essentially be no-ops. */
+    ret = ssl_load_buffered_record( ssl );
+    if( ret != 0 )
+        return( ret );
+#endif /* MBEDTLS_SSL_PROTO_DTLS */
 
     if( ( ret = mbedtls_ssl_fetch_input( ssl, mbedtls_ssl_hdr_len( ssl ) ) ) != 0 )
     {
@@ -4141,6 +4974,16 @@ int mbedtls_ssl_read_record_layer( mbedtls_ssl_context *ssl )
         if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
             ret != MBEDTLS_ERR_SSL_CLIENT_RECONNECT )
         {
+            if( ret == MBEDTLS_ERR_SSL_EARLY_MESSAGE )
+            {
+                ret = ssl_buffer_future_record( ssl );
+                if( ret != 0 )
+                    return( ret );
+
+                /* Fall through to handling of unexpected records */
+                ret = MBEDTLS_ERR_SSL_UNEXPECTED_RECORD;
+            }
+
             if( ret == MBEDTLS_ERR_SSL_UNEXPECTED_RECORD )
             {
                 /* Skip unexpected record (but not whole datagram) */
@@ -4272,6 +5115,39 @@ int mbedtls_ssl_handle_message_type( mbedtls_ssl_context *ssl )
         }
     }
 
+    if( ssl->in_msgtype == MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC )
+    {
+        if( ssl->in_msglen != 1 )
+        {
+            MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid CCS message, len: %d",
+                           ssl->in_msglen ) );
+            return( MBEDTLS_ERR_SSL_INVALID_RECORD );
+        }
+
+        if( ssl->in_msg[0] != 1 )
+        {
+            MBEDTLS_SSL_DEBUG_MSG( 1, ( "invalid CCS message, content: %02x",
+                                        ssl->in_msg[0] ) );
+            return( MBEDTLS_ERR_SSL_INVALID_RECORD );
+        }
+
+#if defined(MBEDTLS_SSL_PROTO_DTLS)
+        if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
+            ssl->state != MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC    &&
+            ssl->state != MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC )
+        {
+            if( ssl->handshake == NULL )
+            {
+                MBEDTLS_SSL_DEBUG_MSG( 1, ( "dropping ChangeCipherSpec outside handshake" ) );
+                return( MBEDTLS_ERR_SSL_UNEXPECTED_RECORD );
+            }
+
+            MBEDTLS_SSL_DEBUG_MSG( 1, ( "received out-of-order ChangeCipherSpec - remember" ) );
+            return( MBEDTLS_ERR_SSL_EARLY_MESSAGE );
+        }
+#endif
+    }
+
     if( ssl->in_msgtype == MBEDTLS_SSL_MSG_ALERT )
     {
         if( ssl->in_msglen != 2 )
@@ -4373,7 +5249,7 @@ int mbedtls_ssl_send_alert_message( mbedtls_ssl_context *ssl,
     ssl->out_msg[0] = level;
     ssl->out_msg[1] = message;
 
-    if( ( ret = mbedtls_ssl_write_record( ssl ) ) != 0 )
+    if( ( ret = mbedtls_ssl_write_record( ssl, SSL_FORCE_FLUSH ) ) != 0 )
     {
         MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_record", ret );
         return( ret );
@@ -4542,9 +5418,9 @@ int mbedtls_ssl_write_certificate( mbedtls_ssl_context *ssl )
 
     ssl->state++;
 
-    if( ( ret = mbedtls_ssl_write_record( ssl ) ) != 0 )
+    if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
     {
-        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_record", ret );
+        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret );
         return( ret );
     }
 
@@ -4597,7 +5473,7 @@ int mbedtls_ssl_parse_certificate( mbedtls_ssl_context *ssl )
     }
 #endif
 
-    if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 )
+    if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
     {
         /* mbedtls_ssl_read_record may have sent an alert already. We
            let it decide whether to alert. */
@@ -4955,9 +5831,9 @@ int mbedtls_ssl_write_change_cipher_spec( mbedtls_ssl_context *ssl )
 
     ssl->state++;
 
-    if( ( ret = mbedtls_ssl_write_record( ssl ) ) != 0 )
+    if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
     {
-        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_record", ret );
+        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret );
         return( ret );
     }
 
@@ -4972,7 +5848,7 @@ int mbedtls_ssl_parse_change_cipher_spec( mbedtls_ssl_context *ssl )
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> parse change cipher spec" ) );
 
-    if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 )
+    if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
     {
         MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret );
         return( ret );
@@ -4986,13 +5862,8 @@ int mbedtls_ssl_parse_change_cipher_spec( mbedtls_ssl_context *ssl )
         return( MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE );
     }
 
-    if( ssl->in_msglen != 1 || ssl->in_msg[0] != 1 )
-    {
-        MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad change cipher spec message" ) );
-        mbedtls_ssl_send_alert_message( ssl, MBEDTLS_SSL_ALERT_LEVEL_FATAL,
-                                        MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR );
-        return( MBEDTLS_ERR_SSL_BAD_HS_CHANGE_CIPHER_SPEC );
-    }
+    /* CCS records are only accepted if they have length 1 and content '1',
+     * so we don't need to check this here. */
 
     /*
      * Switch to our negotiated transform and session parameters for inbound
@@ -5022,16 +5893,7 @@ int mbedtls_ssl_parse_change_cipher_spec( mbedtls_ssl_context *ssl )
 #endif /* MBEDTLS_SSL_PROTO_DTLS */
     memset( ssl->in_ctr, 0, 8 );
 
-    /*
-     * Set the in_msg pointer to the correct location based on IV length
-     */
-    if( ssl->minor_ver >= MBEDTLS_SSL_MINOR_VERSION_2 )
-    {
-        ssl->in_msg = ssl->in_iv + ssl->transform_negotiate->ivlen -
-                      ssl->transform_negotiate->fixed_ivlen;
-    }
-    else
-        ssl->in_msg = ssl->in_iv;
+    ssl_update_in_pointers( ssl, ssl->transform_negotiate );
 
 #if defined(MBEDTLS_SSL_HW_RECORD_ACCEL)
     if( mbedtls_ssl_hw_record_activate != NULL )
@@ -5482,16 +6344,7 @@ int mbedtls_ssl_write_finished( mbedtls_ssl_context *ssl )
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "=> write finished" ) );
 
-    /*
-     * Set the out_msg pointer to the correct location based on IV length
-     */
-    if( ssl->minor_ver >= MBEDTLS_SSL_MINOR_VERSION_2 )
-    {
-        ssl->out_msg = ssl->out_iv + ssl->transform_negotiate->ivlen -
-                       ssl->transform_negotiate->fixed_ivlen;
-    }
-    else
-        ssl->out_msg = ssl->out_iv;
+    ssl_update_out_pointers( ssl, ssl->transform_negotiate );
 
     ssl->handshake->calc_finished( ssl, ssl->out_msg + 4, ssl->conf->endpoint );
 
@@ -5543,14 +6396,14 @@ int mbedtls_ssl_write_finished( mbedtls_ssl_context *ssl )
 
         /* Remember current epoch settings for resending */
         ssl->handshake->alt_transform_out = ssl->transform_out;
-        memcpy( ssl->handshake->alt_out_ctr, ssl->out_ctr, 8 );
+        memcpy( ssl->handshake->alt_out_ctr, ssl->cur_out_ctr, 8 );
 
         /* Set sequence_number to zero */
-        memset( ssl->out_ctr + 2, 0, 6 );
+        memset( ssl->cur_out_ctr + 2, 0, 6 );
 
         /* Increment epoch */
         for( i = 2; i > 0; i-- )
-            if( ++ssl->out_ctr[i - 1] != 0 )
+            if( ++ssl->cur_out_ctr[i - 1] != 0 )
                 break;
 
         /* The loop goes to its end iff the counter is wrapping */
@@ -5562,7 +6415,7 @@ int mbedtls_ssl_write_finished( mbedtls_ssl_context *ssl )
     }
     else
 #endif /* MBEDTLS_SSL_PROTO_DTLS */
-    memset( ssl->out_ctr, 0, 8 );
+    memset( ssl->cur_out_ctr, 0, 8 );
 
     ssl->transform_out = ssl->transform_negotiate;
     ssl->session_out = ssl->session_negotiate;
@@ -5583,11 +6436,20 @@ int mbedtls_ssl_write_finished( mbedtls_ssl_context *ssl )
         mbedtls_ssl_send_flight_completed( ssl );
 #endif
 
-    if( ( ret = mbedtls_ssl_write_record( ssl ) ) != 0 )
+    if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
     {
-        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_record", ret );
+        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret );
+        return( ret );
+    }
+
+#if defined(MBEDTLS_SSL_PROTO_DTLS)
+    if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM &&
+        ( ret = mbedtls_ssl_flight_transmit( ssl ) ) != 0 )
+    {
+        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_flight_transmit", ret );
         return( ret );
     }
+#endif
 
     MBEDTLS_SSL_DEBUG_MSG( 2, ( "<= write finished" ) );
 
@@ -5610,7 +6472,7 @@ int mbedtls_ssl_parse_finished( mbedtls_ssl_context *ssl )
 
     ssl->handshake->calc_finished( ssl, buf, ssl->conf->endpoint ^ 1 );
 
-    if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 )
+    if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
     {
         MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_read_record", ret );
         return( ret );
@@ -5841,6 +6703,78 @@ static int ssl_cookie_check_dummy( void *ctx,
 }
 #endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY && MBEDTLS_SSL_SRV_C */
 
+/* Once ssl->out_hdr as the address of the beginning of the
+ * next outgoing record is set, deduce the other pointers.
+ *
+ * Note: For TLS, we save the implicit record sequence number
+ *       (entering MAC computation) in the 8 bytes before ssl->out_hdr,
+ *       and the caller has to make sure there's space for this.
+ */
+
+static void ssl_update_out_pointers( mbedtls_ssl_context *ssl,
+                                     mbedtls_ssl_transform *transform )
+{
+#if defined(MBEDTLS_SSL_PROTO_DTLS)
+    if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
+    {
+        ssl->out_ctr = ssl->out_hdr +  3;
+        ssl->out_len = ssl->out_hdr + 11;
+        ssl->out_iv  = ssl->out_hdr + 13;
+    }
+    else
+#endif
+    {
+        ssl->out_ctr = ssl->out_hdr - 8;
+        ssl->out_len = ssl->out_hdr + 3;
+        ssl->out_iv  = ssl->out_hdr + 5;
+    }
+
+    /* Adjust out_msg to make space for explicit IV, if used. */
+    if( transform != NULL &&
+        ssl->minor_ver >= MBEDTLS_SSL_MINOR_VERSION_2 )
+    {
+        ssl->out_msg = ssl->out_iv + transform->ivlen - transform->fixed_ivlen;
+    }
+    else
+        ssl->out_msg = ssl->out_iv;
+}
+
+/* Once ssl->in_hdr as the address of the beginning of the
+ * next incoming record is set, deduce the other pointers.
+ *
+ * Note: For TLS, we save the implicit record sequence number
+ *       (entering MAC computation) in the 8 bytes before ssl->in_hdr,
+ *       and the caller has to make sure there's space for this.
+ */
+
+static void ssl_update_in_pointers( mbedtls_ssl_context *ssl,
+                                    mbedtls_ssl_transform *transform )
+{
+#if defined(MBEDTLS_SSL_PROTO_DTLS)
+    if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
+    {
+        ssl->in_ctr = ssl->in_hdr +  3;
+        ssl->in_len = ssl->in_hdr + 11;
+        ssl->in_iv  = ssl->in_hdr + 13;
+    }
+    else
+#endif
+    {
+        ssl->in_ctr = ssl->in_hdr - 8;
+        ssl->in_len = ssl->in_hdr + 3;
+        ssl->in_iv  = ssl->in_hdr + 5;
+    }
+
+    /* Offset in_msg from in_iv to allow space for explicit IV, if used. */
+    if( transform != NULL &&
+        ssl->minor_ver >= MBEDTLS_SSL_MINOR_VERSION_2 )
+    {
+        ssl->in_msg = ssl->in_iv + transform->ivlen - transform->fixed_ivlen;
+    }
+    else
+        ssl->in_msg = ssl->in_iv;
+}
+
 /*
  * Initialize an SSL context
  */
@@ -5852,6 +6786,28 @@ void mbedtls_ssl_init( mbedtls_ssl_context *ssl )
 /*
  * Setup an SSL context
  */
+
+static void ssl_reset_in_out_pointers( mbedtls_ssl_context *ssl )
+{
+    /* Set the incoming and outgoing record pointers. */
+#if defined(MBEDTLS_SSL_PROTO_DTLS)
+    if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
+    {
+        ssl->out_hdr = ssl->out_buf;
+        ssl->in_hdr  = ssl->in_buf;
+    }
+    else
+#endif /* MBEDTLS_SSL_PROTO_DTLS */
+    {
+        ssl->out_hdr = ssl->out_buf + 8;
+        ssl->in_hdr  = ssl->in_buf  + 8;
+    }
+
+    /* Derive other internal pointers. */
+    ssl_update_out_pointers( ssl, NULL /* no transform enabled */ );
+    ssl_update_in_pointers ( ssl, NULL /* no transform enabled */ );
+}
+
 int mbedtls_ssl_setup( mbedtls_ssl_context *ssl,
                        const mbedtls_ssl_config *conf )
 {
@@ -5862,57 +6818,55 @@ int mbedtls_ssl_setup( mbedtls_ssl_context *ssl,
     /*
      * Prepare base structures
      */
+
+    /* Set to NULL in case of an error condition */
+    ssl->out_buf = NULL;
+
     ssl->in_buf = mbedtls_calloc( 1, MBEDTLS_SSL_IN_BUFFER_LEN );
     if( ssl->in_buf == NULL )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "alloc(%d bytes) failed", MBEDTLS_SSL_IN_BUFFER_LEN) );
-        return( MBEDTLS_ERR_SSL_ALLOC_FAILED );
+        ret = MBEDTLS_ERR_SSL_ALLOC_FAILED;
+        goto error;
     }
 
     ssl->out_buf = mbedtls_calloc( 1, MBEDTLS_SSL_OUT_BUFFER_LEN );
     if( ssl->out_buf == NULL )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "alloc(%d bytes) failed", MBEDTLS_SSL_OUT_BUFFER_LEN) );
-        mbedtls_free( ssl->in_buf );
-        ssl->in_buf = NULL;
-        return( MBEDTLS_ERR_SSL_ALLOC_FAILED );
-    }
-
-#if defined(MBEDTLS_SSL_PROTO_DTLS)
-    if( conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
-    {
-        ssl->out_hdr = ssl->out_buf;
-        ssl->out_ctr = ssl->out_buf +  3;
-        ssl->out_len = ssl->out_buf + 11;
-        ssl->out_iv  = ssl->out_buf + 13;
-        ssl->out_msg = ssl->out_buf + 13;
-
-        ssl->in_hdr = ssl->in_buf;
-        ssl->in_ctr = ssl->in_buf +  3;
-        ssl->in_len = ssl->in_buf + 11;
-        ssl->in_iv  = ssl->in_buf + 13;
-        ssl->in_msg = ssl->in_buf + 13;
+        ret = MBEDTLS_ERR_SSL_ALLOC_FAILED;
+        goto error;
     }
-    else
-#endif
-    {
-        ssl->out_ctr = ssl->out_buf;
-        ssl->out_hdr = ssl->out_buf +  8;
-        ssl->out_len = ssl->out_buf + 11;
-        ssl->out_iv  = ssl->out_buf + 13;
-        ssl->out_msg = ssl->out_buf + 13;
 
-        ssl->in_ctr = ssl->in_buf;
-        ssl->in_hdr = ssl->in_buf +  8;
-        ssl->in_len = ssl->in_buf + 11;
-        ssl->in_iv  = ssl->in_buf + 13;
-        ssl->in_msg = ssl->in_buf + 13;
-    }
+    ssl_reset_in_out_pointers( ssl );
 
     if( ( ret = ssl_handshake_init( ssl ) ) != 0 )
-        return( ret );
+        goto error;
 
     return( 0 );
+
+error:
+    mbedtls_free( ssl->in_buf );
+    mbedtls_free( ssl->out_buf );
+
+    ssl->conf = NULL;
+
+    ssl->in_buf = NULL;
+    ssl->out_buf = NULL;
+
+    ssl->in_hdr = NULL;
+    ssl->in_ctr = NULL;
+    ssl->in_len = NULL;
+    ssl->in_iv = NULL;
+    ssl->in_msg = NULL;
+
+    ssl->out_hdr = NULL;
+    ssl->out_ctr = NULL;
+    ssl->out_len = NULL;
+    ssl->out_iv = NULL;
+    ssl->out_msg = NULL;
+
+    return( ret );
 }
 
 /*
@@ -5926,6 +6880,11 @@ static int ssl_session_reset_int( mbedtls_ssl_context *ssl, int partial )
 {
     int ret;
 
+#if !defined(MBEDTLS_SSL_DTLS_CLIENT_PORT_REUSE) ||     \
+    !defined(MBEDTLS_SSL_SRV_C)
+    ((void) partial);
+#endif
+
     ssl->state = MBEDTLS_SSL_HELLO_REQUEST;
 
     /* Cancel any possibly running timer */
@@ -5942,12 +6901,10 @@ static int ssl_session_reset_int( mbedtls_ssl_context *ssl, int partial )
     ssl->secure_renegotiation = MBEDTLS_SSL_LEGACY_RENEGOTIATION;
 
     ssl->in_offt = NULL;
+    ssl_reset_in_out_pointers( ssl );
 
-    ssl->in_msg = ssl->in_buf + 13;
     ssl->in_msgtype = 0;
     ssl->in_msglen = 0;
-    if( partial == 0 )
-        ssl->in_left = 0;
 #if defined(MBEDTLS_SSL_PROTO_DTLS)
     ssl->next_record_offset = 0;
     ssl->in_epoch = 0;
@@ -5961,7 +6918,6 @@ static int ssl_session_reset_int( mbedtls_ssl_context *ssl, int partial )
 
     ssl->keep_current_message = 0;
 
-    ssl->out_msg = ssl->out_buf + 13;
     ssl->out_msgtype = 0;
     ssl->out_msglen = 0;
     ssl->out_left = 0;
@@ -5970,12 +6926,23 @@ static int ssl_session_reset_int( mbedtls_ssl_context *ssl, int partial )
         ssl->split_done = 0;
 #endif
 
+    memset( ssl->cur_out_ctr, 0, sizeof( ssl->cur_out_ctr ) );
+
     ssl->transform_in = NULL;
     ssl->transform_out = NULL;
 
+    ssl->session_in = NULL;
+    ssl->session_out = NULL;
+
     memset( ssl->out_buf, 0, MBEDTLS_SSL_OUT_BUFFER_LEN );
+
+#if defined(MBEDTLS_SSL_DTLS_CLIENT_PORT_REUSE) && defined(MBEDTLS_SSL_SRV_C)
     if( partial == 0 )
+#endif /* MBEDTLS_SSL_DTLS_CLIENT_PORT_REUSE && MBEDTLS_SSL_SRV_C */
+    {
+        ssl->in_left = 0;
         memset( ssl->in_buf, 0, MBEDTLS_SSL_IN_BUFFER_LEN );
+    }
 
 #if defined(MBEDTLS_SSL_HW_RECORD_ACCEL)
     if( mbedtls_ssl_hw_record_reset != NULL )
@@ -6008,7 +6975,9 @@ static int ssl_session_reset_int( mbedtls_ssl_context *ssl, int partial )
 #endif
 
 #if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY) && defined(MBEDTLS_SSL_SRV_C)
+#if defined(MBEDTLS_SSL_DTLS_CLIENT_PORT_REUSE)
     if( partial == 0 )
+#endif
     {
         mbedtls_free( ssl->cli_id );
         ssl->cli_id = NULL;
@@ -6059,7 +7028,15 @@ void mbedtls_ssl_conf_dtls_badmac_limit( mbedtls_ssl_config *conf, unsigned limi
 #endif
 
 #if defined(MBEDTLS_SSL_PROTO_DTLS)
-void mbedtls_ssl_conf_handshake_timeout( mbedtls_ssl_config *conf, uint32_t min, uint32_t max )
+
+void mbedtls_ssl_set_datagram_packing( mbedtls_ssl_context *ssl,
+                                       unsigned allow_packing )
+{
+    ssl->disable_datagram_packing = !allow_packing;
+}
+
+void mbedtls_ssl_conf_handshake_timeout( mbedtls_ssl_config *conf,
+                                         uint32_t min, uint32_t max )
 {
     conf->hs_timeout_min = min;
     conf->hs_timeout_max = max;
@@ -6109,6 +7086,13 @@ void mbedtls_ssl_set_bio( mbedtls_ssl_context *ssl,
     ssl->f_recv_timeout = f_recv_timeout;
 }
 
+#if defined(MBEDTLS_SSL_PROTO_DTLS)
+void mbedtls_ssl_set_mtu( mbedtls_ssl_context *ssl, uint16_t mtu )
+{
+    ssl->mtu = mtu;
+}
+#endif
+
 void mbedtls_ssl_conf_read_timeout( mbedtls_ssl_config *conf, uint32_t timeout )
 {
     conf->read_timeout   = timeout;
@@ -6772,7 +7756,7 @@ int mbedtls_ssl_check_pending( const mbedtls_ssl_context *ssl )
 
     /*
      * In all other cases, the rest of the message can be dropped.
-     * As in ssl_read_record_layer, this needs to be adapted if
+     * As in ssl_get_next_record, this needs to be adapted if
      * we implement support for multiple alerts in single records.
      */
 
@@ -6839,28 +7823,47 @@ const char *mbedtls_ssl_get_version( const mbedtls_ssl_context *ssl )
 
 int mbedtls_ssl_get_record_expansion( const mbedtls_ssl_context *ssl )
 {
-    size_t transform_expansion;
+    size_t transform_expansion = 0;
     const mbedtls_ssl_transform *transform = ssl->transform_out;
+    unsigned block_size;
+
+    if( transform == NULL )
+        return( (int) mbedtls_ssl_hdr_len( ssl ) );
 
 #if defined(MBEDTLS_ZLIB_SUPPORT)
     if( ssl->session_out->compression != MBEDTLS_SSL_COMPRESS_NULL )
         return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
 #endif
 
-    if( transform == NULL )
-        return( (int) mbedtls_ssl_hdr_len( ssl ) );
-
     switch( mbedtls_cipher_get_cipher_mode( &transform->cipher_ctx_enc ) )
     {
         case MBEDTLS_MODE_GCM:
         case MBEDTLS_MODE_CCM:
+        case MBEDTLS_MODE_CHACHAPOLY:
         case MBEDTLS_MODE_STREAM:
             transform_expansion = transform->minlen;
             break;
 
         case MBEDTLS_MODE_CBC:
-            transform_expansion = transform->maclen
-                      + mbedtls_cipher_get_block_size( &transform->cipher_ctx_enc );
+
+            block_size = mbedtls_cipher_get_block_size(
+                &transform->cipher_ctx_enc );
+
+            /* Expansion due to the addition of the MAC. */
+            transform_expansion += transform->maclen;
+
+            /* Expansion due to the addition of CBC padding;
+             * Theoretically up to 256 bytes, but we never use
+             * more than the block size of the underlying cipher. */
+            transform_expansion += block_size;
+
+            /* For TLS 1.1 or higher, an explicit IV is added
+             * after the record header. */
+#if defined(MBEDTLS_SSL_PROTO_TLS1_1) || defined(MBEDTLS_SSL_PROTO_TLS1_2)
+            if( ssl->minor_ver >= MBEDTLS_SSL_MINOR_VERSION_2 )
+                transform_expansion += block_size;
+#endif /* MBEDTLS_SSL_PROTO_TLS1_1 || MBEDTLS_SSL_PROTO_TLS1_2 */
+
             break;
 
         default:
@@ -6881,19 +7884,83 @@ size_t mbedtls_ssl_get_max_frag_len( const mbedtls_ssl_context *ssl )
      */
     max_len = ssl_mfl_code_to_length( ssl->conf->mfl_code );
 
-    /*
-     * Check if a smaller max length was negotiated
-     */
+    /* Check if a smaller max length was negotiated */
     if( ssl->session_out != NULL &&
         ssl_mfl_code_to_length( ssl->session_out->mfl_code ) < max_len )
     {
         max_len = ssl_mfl_code_to_length( ssl->session_out->mfl_code );
     }
 
-    return max_len;
+    /* During a handshake, use the value being negotiated */
+    if( ssl->session_negotiate != NULL &&
+        ssl_mfl_code_to_length( ssl->session_negotiate->mfl_code ) < max_len )
+    {
+        max_len = ssl_mfl_code_to_length( ssl->session_negotiate->mfl_code );
+    }
+
+    return( max_len );
 }
 #endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
 
+#if defined(MBEDTLS_SSL_PROTO_DTLS)
+static size_t ssl_get_current_mtu( const mbedtls_ssl_context *ssl )
+{
+    if( ssl->handshake == NULL || ssl->handshake->mtu == 0 )
+        return( ssl->mtu );
+
+    if( ssl->mtu == 0 )
+        return( ssl->handshake->mtu );
+
+    return( ssl->mtu < ssl->handshake->mtu ?
+            ssl->mtu : ssl->handshake->mtu );
+}
+#endif /* MBEDTLS_SSL_PROTO_DTLS */
+
+int mbedtls_ssl_get_max_out_record_payload( const mbedtls_ssl_context *ssl )
+{
+    size_t max_len = MBEDTLS_SSL_OUT_CONTENT_LEN;
+
+#if !defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH) && \
+    !defined(MBEDTLS_SSL_PROTO_DTLS)
+    (void) ssl;
+#endif
+
+#if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
+    const size_t mfl = mbedtls_ssl_get_max_frag_len( ssl );
+
+    if( max_len > mfl )
+        max_len = mfl;
+#endif
+
+#if defined(MBEDTLS_SSL_PROTO_DTLS)
+    if( ssl_get_current_mtu( ssl ) != 0 )
+    {
+        const size_t mtu = ssl_get_current_mtu( ssl );
+        const int ret = mbedtls_ssl_get_record_expansion( ssl );
+        const size_t overhead = (size_t) ret;
+
+        if( ret < 0 )
+            return( ret );
+
+        if( mtu <= overhead )
+        {
+            MBEDTLS_SSL_DEBUG_MSG( 1, ( "MTU too low for record expansion" ) );
+            return( MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE );
+        }
+
+        if( max_len > mtu - overhead )
+            max_len = mtu - overhead;
+    }
+#endif /* MBEDTLS_SSL_PROTO_DTLS */
+
+#if !defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH) &&        \
+    !defined(MBEDTLS_SSL_PROTO_DTLS)
+    ((void) ssl);
+#endif
+
+    return( (int) max_len );
+}
+
 #if defined(MBEDTLS_X509_CRT_PARSE_C)
 const mbedtls_x509_crt *mbedtls_ssl_get_peer_cert( const mbedtls_ssl_context *ssl )
 {
@@ -6981,9 +8048,9 @@ static int ssl_write_hello_request( mbedtls_ssl_context *ssl )
     ssl->out_msgtype = MBEDTLS_SSL_MSG_HANDSHAKE;
     ssl->out_msg[0]  = MBEDTLS_SSL_HS_HELLO_REQUEST;
 
-    if( ( ret = mbedtls_ssl_write_record( ssl ) ) != 0 )
+    if( ( ret = mbedtls_ssl_write_handshake_msg( ssl ) ) != 0 )
     {
-        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_record", ret );
+        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_handshake_msg", ret );
         return( ret );
     }
 
@@ -7113,7 +8180,7 @@ static int ssl_check_ctr_renegotiate( mbedtls_ssl_context *ssl )
 
     in_ctr_cmp = memcmp( ssl->in_ctr + ep_len,
                         ssl->conf->renego_period + ep_len, 8 - ep_len );
-    out_ctr_cmp = memcmp( ssl->out_ctr + ep_len,
+    out_ctr_cmp = memcmp( ssl->cur_out_ctr + ep_len,
                           ssl->conf->renego_period + ep_len, 8 - ep_len );
 
     if( in_ctr_cmp <= 0 && out_ctr_cmp <= 0 )
@@ -7148,7 +8215,7 @@ int mbedtls_ssl_read( mbedtls_ssl_context *ssl, unsigned char *buf, size_t len )
         if( ssl->handshake != NULL &&
             ssl->handshake->retransmit_state == MBEDTLS_SSL_RETRANS_SENDING )
         {
-            if( ( ret = mbedtls_ssl_resend( ssl ) ) != 0 )
+            if( ( ret = mbedtls_ssl_flight_transmit( ssl ) ) != 0 )
                 return( ret );
         }
     }
@@ -7197,7 +8264,7 @@ int mbedtls_ssl_read( mbedtls_ssl_context *ssl, unsigned char *buf, size_t len )
             ssl_set_timer( ssl, ssl->conf->read_timeout );
         }
 
-        if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 )
+        if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
         {
             if( ret == MBEDTLS_ERR_SSL_CONN_EOF )
                 return( 0 );
@@ -7212,7 +8279,7 @@ int mbedtls_ssl_read( mbedtls_ssl_context *ssl, unsigned char *buf, size_t len )
             /*
              * OpenSSL sends empty messages to randomize the IV
              */
-            if( ( ret = mbedtls_ssl_read_record( ssl ) ) != 0 )
+            if( ( ret = mbedtls_ssl_read_record( ssl, 1 ) ) != 0 )
             {
                 if( ret == MBEDTLS_ERR_SSL_CONN_EOF )
                     return( 0 );
@@ -7445,12 +8512,15 @@ int mbedtls_ssl_read( mbedtls_ssl_context *ssl, unsigned char *buf, size_t len )
 static int ssl_write_real( mbedtls_ssl_context *ssl,
                            const unsigned char *buf, size_t len )
 {
-    int ret;
-#if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
-    size_t max_len = mbedtls_ssl_get_max_frag_len( ssl );
-#else
-    size_t max_len = MBEDTLS_SSL_OUT_CONTENT_LEN;
-#endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
+    int ret = mbedtls_ssl_get_max_out_record_payload( ssl );
+    const size_t max_len = (size_t) ret;
+
+    if( ret < 0 )
+    {
+        MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_get_max_out_record_payload", ret );
+        return( ret );
+    }
+
     if( len > max_len )
     {
 #if defined(MBEDTLS_SSL_PROTO_DTLS)
@@ -7491,7 +8561,7 @@ static int ssl_write_real( mbedtls_ssl_context *ssl,
         ssl->out_msgtype = MBEDTLS_SSL_MSG_APPLICATION_DATA;
         memcpy( ssl->out_msg, buf, len );
 
-        if( ( ret = mbedtls_ssl_write_record( ssl ) ) != 0 )
+        if( ( ret = mbedtls_ssl_write_record( ssl, SSL_FORCE_FLUSH ) ) != 0 )
         {
             MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_write_record", ret );
             return( ret );
@@ -7643,6 +8713,41 @@ static void ssl_key_cert_free( mbedtls_ssl_key_cert *key_cert )
 }
 #endif /* MBEDTLS_X509_CRT_PARSE_C */
 
+#if defined(MBEDTLS_SSL_PROTO_DTLS)
+
+static void ssl_buffering_free( mbedtls_ssl_context *ssl )
+{
+    unsigned offset;
+    mbedtls_ssl_handshake_params * const hs = ssl->handshake;
+
+    if( hs == NULL )
+        return;
+
+    ssl_free_buffered_record( ssl );
+
+    for( offset = 0; offset < MBEDTLS_SSL_MAX_BUFFERED_HS; offset++ )
+        ssl_buffering_free_slot( ssl, offset );
+}
+
+static void ssl_buffering_free_slot( mbedtls_ssl_context *ssl,
+                                     uint8_t slot )
+{
+    mbedtls_ssl_handshake_params * const hs = ssl->handshake;
+    mbedtls_ssl_hs_buffer * const hs_buf = &hs->buffering.hs[slot];
+
+    if( slot >= MBEDTLS_SSL_MAX_BUFFERED_HS )
+        return;
+
+    if( hs_buf->is_valid == 1 )
+    {
+        hs->buffering.total_bytes_buffered -= hs_buf->data_len;
+        mbedtls_free( hs_buf->data );
+        memset( hs_buf, 0, sizeof( mbedtls_ssl_hs_buffer ) );
+    }
+}
+
+#endif /* MBEDTLS_SSL_PROTO_DTLS */
+
 void mbedtls_ssl_handshake_free( mbedtls_ssl_context *ssl )
 {
     mbedtls_ssl_handshake_params *handshake = ssl->handshake;
@@ -7722,8 +8827,8 @@ void mbedtls_ssl_handshake_free( mbedtls_ssl_context *ssl )
 
 #if defined(MBEDTLS_SSL_PROTO_DTLS)
     mbedtls_free( handshake->verify_cookie );
-    mbedtls_free( handshake->hs_msg );
     ssl_flight_free( handshake->flight );
+    ssl_buffering_free( ssl );
 #endif
 
     mbedtls_platform_zeroize( handshake,
diff --git a/crypto/mbedtls/src/x509_crt.c b/crypto/mbedtls/src/x509_crt.c
index 290c1eb3d1..a390f81ca0 100644
--- a/crypto/mbedtls/src/x509_crt.c
+++ b/crypto/mbedtls/src/x509_crt.c
@@ -163,6 +163,9 @@ const mbedtls_x509_crt_profile mbedtls_x509_crt_profile_suiteb =
 static int x509_profile_check_md_alg( const mbedtls_x509_crt_profile *profile,
                                       mbedtls_md_type_t md_alg )
 {
+    if( md_alg == MBEDTLS_MD_NONE )
+        return( -1 );
+
     if( ( profile->allowed_mds & MBEDTLS_X509_ID_FLAG( md_alg ) ) != 0 )
         return( 0 );
 
@@ -176,6 +179,9 @@ static int x509_profile_check_md_alg( const mbedtls_x509_crt_profile *profile,
 static int x509_profile_check_pk_alg( const mbedtls_x509_crt_profile *profile,
                                       mbedtls_pk_type_t pk_alg )
 {
+    if( pk_alg == MBEDTLS_PK_NONE )
+        return( -1 );
+
     if( ( profile->allowed_pks & MBEDTLS_X509_ID_FLAG( pk_alg ) ) != 0 )
         return( 0 );
 
@@ -208,6 +214,9 @@ static int x509_profile_check_key( const mbedtls_x509_crt_profile *profile,
     {
         const mbedtls_ecp_group_id gid = mbedtls_pk_ec( *pk )->grp.id;
 
+        if( gid == MBEDTLS_ECP_DP_NONE )
+            return( -1 );
+
         if( ( profile->allowed_curves & MBEDTLS_X509_ID_FLAG( gid ) ) != 0 )
             return( 0 );
 
@@ -570,18 +579,14 @@ static int x509_get_crt_ext( unsigned char **p,
         end_ext_data = *p + len;
 
         /* Get extension ID */
-        extn_oid.tag = **p;
-
-        if( ( ret = mbedtls_asn1_get_tag( p, end, &extn_oid.len, MBEDTLS_ASN1_OID ) ) != 0 )
+        if( ( ret = mbedtls_asn1_get_tag( p, end_ext_data, &extn_oid.len,
+                                          MBEDTLS_ASN1_OID ) ) != 0 )
             return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS + ret );
 
+        extn_oid.tag = MBEDTLS_ASN1_OID;
         extn_oid.p = *p;
         *p += extn_oid.len;
 
-        if( ( end - *p ) < 1 )
-            return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS +
-                    MBEDTLS_ERR_ASN1_OUT_OF_DATA );
-
         /* Get optional critical */
         if( ( ret = mbedtls_asn1_get_bool( p, end_ext_data, &is_critical ) ) != 0 &&
             ( ret != MBEDTLS_ERR_ASN1_UNEXPECTED_TAG ) )


 

----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on GitHub and use the
URL above to go to the specific comment.
 
For queries about this service, please contact Infrastructure at:
users@infra.apache.org


With regards,
Apache Git Services