diff --git a/include/mbedtls/compat-1.3.h b/include/mbedtls/compat-1.3.h
index 600a0f1..213b691 100644
--- a/include/mbedtls/compat-1.3.h
+++ b/include/mbedtls/compat-1.3.h
@@ -1378,7 +1378,8 @@
 #define SSL_ANTI_REPLAY_ENABLED MBEDTLS_SSL_ANTI_REPLAY_ENABLED
 #define SSL_ARC4_DISABLED MBEDTLS_SSL_ARC4_DISABLED
 #define SSL_ARC4_ENABLED MBEDTLS_SSL_ARC4_ENABLED
-#define SSL_BUFFER_LEN MBEDTLS_SSL_BUFFER_LEN
+#define SSL_BUFFER_LEN ( ( ( MBEDTLS_SSL_IN_BUFFER_LEN ) < ( MBEDTLS_SSL_OUT_BUFFER_LEN ) ) \
+                         ? ( MBEDTLS_SSL_IN_BUFFER_LEN ) : ( MBEDTLS_SSL_OUT_BUFFER_LEN ) )
 #define SSL_CACHE_DEFAULT_MAX_ENTRIES MBEDTLS_SSL_CACHE_DEFAULT_MAX_ENTRIES
 #define SSL_CACHE_DEFAULT_TIMEOUT MBEDTLS_SSL_CACHE_DEFAULT_TIMEOUT
 #define SSL_CBC_RECORD_SPLITTING_DISABLED MBEDTLS_SSL_CBC_RECORD_SPLITTING_DISABLED
diff --git a/include/mbedtls/config.h b/include/mbedtls/config.h
index e13026e..6b44ebe 100644
--- a/include/mbedtls/config.h
+++ b/include/mbedtls/config.h
@@ -2951,7 +2951,51 @@
 //#define MBEDTLS_SSL_CACHE_DEFAULT_MAX_ENTRIES      50 /**< Maximum entries in cache */
 
 /* SSL options */
-//#define MBEDTLS_SSL_MAX_CONTENT_LEN             16384 /**< Maxium fragment length in bytes, determines the size of each of the two internal I/O buffers */
+
+/** \def MBEDTLS_SSL_MAX_CONTENT_LEN
+ *
+ * Maximum fragment length in bytes.
+ *
+ * Determines the size of both the incoming and outgoing TLS I/O buffers.
+ *
+ * Uncommenting MBEDTLS_SSL_IN_CONTENT_LEN and/or MBEDTLS_SSL_OUT_CONTENT_LEN
+ * will override this length by setting maximum incoming and/or outgoing
+ * fragment length, respectively.
+ */
+//#define MBEDTLS_SSL_MAX_CONTENT_LEN             16384
+
+/** \def MBEDTLS_SSL_IN_CONTENT_LEN
+ *
+ * Maximum incoming fragment length in bytes.
+ *
+ * Uncomment to set the size of the inward TLS buffer independently of the
+ * outward buffer.
+ */
+//#define MBEDTLS_SSL_IN_CONTENT_LEN              16384
+
+/** \def MBEDTLS_SSL_OUT_CONTENT_LEN
+ *
+ * Maximum outgoing fragment length in bytes.
+ *
+ * Uncomment to set the size of the outward TLS buffer independently of the
+ * inward buffer.
+ *
+ * It is possible to save RAM by setting a smaller outward buffer, while keeping
+ * the default inward 16384 byte buffer to conform to the TLS specification.
+ *
+ * The minimum required outward buffer size is determined by the handshake
+ * protocol's usage. Handshaking will fail if the outward buffer is too small.
+ * The specific size requirement depends on the configured ciphers and any
+ * certificate data which is sent during the handshake.
+ *
+ * For absolute minimum RAM usage, it's best to enable
+ * MBEDTLS_SSL_MAX_FRAGMENT_LENGTH and reduce MBEDTLS_SSL_MAX_CONTENT_LEN. This
+ * reduces both incoming and outgoing buffer sizes. However this is only
+ * guaranteed if the other end of the connection also supports the TLS
+ * max_fragment_len extension. Otherwise the connection may fail.
+ */
+//#define MBEDTLS_SSL_OUT_CONTENT_LEN             16384
+
 //#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/include/mbedtls/ssl.h b/include/mbedtls/ssl.h
index 39b7f29..6c35c45 100644
--- a/include/mbedtls/ssl.h
+++ b/include/mbedtls/ssl.h
@@ -220,7 +220,7 @@
 #endif
 
 /*
- * Maxium fragment length in bytes,
+ * Maximum fragment length in bytes,
  * determines the size of each of the two internal I/O buffers.
  *
  * Note: the RFC defines the default size of SSL / TLS messages. If you
@@ -234,6 +234,14 @@
 #define MBEDTLS_SSL_MAX_CONTENT_LEN         16384   /**< Size of the input / output buffer */
 #endif
 
+#if !defined(MBEDTLS_SSL_IN_CONTENT_LEN)
+#define MBEDTLS_SSL_IN_CONTENT_LEN MBEDTLS_SSL_MAX_CONTENT_LEN
+#endif
+
+#if !defined(MBEDTLS_SSL_OUT_CONTENT_LEN)
+#define MBEDTLS_SSL_OUT_CONTENT_LEN MBEDTLS_SSL_MAX_CONTENT_LEN
+#endif
+
 /* \} name SECTION: Module settings */
 
 /*
@@ -2418,7 +2426,8 @@
 #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
 /**
  * \brief          Set the maximum fragment length to emit and/or negotiate
- *                 (Default: MBEDTLS_SSL_MAX_CONTENT_LEN, usually 2^14 bytes)
+ *                 (Default: the smaller of MBEDTLS_SSL_IN_CONTENT_LEN and
+ *                 MBEDTLS_SSL_OUT_CONTENT_LEN, usually 2^14 bytes)
  *                 (Server: set maximum fragment length to emit,
  *                 usually negotiated by the client during handshake
  *                 (Client: set maximum fragment length to emit *and*
diff --git a/include/mbedtls/ssl_internal.h b/include/mbedtls/ssl_internal.h
index f48fe90..d214703 100644
--- a/include/mbedtls/ssl_internal.h
+++ b/include/mbedtls/ssl_internal.h
@@ -143,32 +143,73 @@
 #define MBEDTLS_SSL_PADDING_ADD              0
 #endif
 
-#define MBEDTLS_SSL_PAYLOAD_LEN ( MBEDTLS_SSL_MAX_CONTENT_LEN    \
-                        + MBEDTLS_SSL_COMPRESSION_ADD            \
-                        + MBEDTLS_MAX_IV_LENGTH                  \
-                        + MBEDTLS_SSL_MAC_ADD                    \
-                        + MBEDTLS_SSL_PADDING_ADD                \
-                        )
+#define MBEDTLS_SSL_PAYLOAD_OVERHEAD ( MBEDTLS_SSL_COMPRESSION_ADD +    \
+                                       MBEDTLS_MAX_IV_LENGTH +          \
+                                       MBEDTLS_SSL_MAC_ADD +            \
+                                       MBEDTLS_SSL_PADDING_ADD          \
+                                       )
+
+#define MBEDTLS_SSL_IN_PAYLOAD_LEN ( MBEDTLS_SSL_PAYLOAD_OVERHEAD + \
+                                     ( MBEDTLS_SSL_IN_CONTENT_LEN ) )
+
+#define MBEDTLS_SSL_OUT_PAYLOAD_LEN ( MBEDTLS_SSL_PAYLOAD_OVERHEAD + \
+                                      ( MBEDTLS_SSL_OUT_CONTENT_LEN ) )
+
+/* 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.)
+ */
+#define MBEDTLS_TLS_EXT_ADV_CONTENT_LEN (                            \
+        (MBEDTLS_SSL_IN_CONTENT_LEN > MBEDTLS_SSL_OUT_CONTENT_LEN)   \
+        ? ( MBEDTLS_SSL_OUT_CONTENT_LEN )                            \
+        : ( MBEDTLS_SSL_IN_CONTENT_LEN )                             \
+        )
 
 /*
  * Check that we obey the standard's message size bounds
  */
 
 #if MBEDTLS_SSL_MAX_CONTENT_LEN > 16384
-#error Bad configuration - record content too large.
+#error "Bad configuration - record content too large."
 #endif
 
-#if MBEDTLS_SSL_PAYLOAD_LEN > 16384 + 2048
-#error Bad configuration - protected record payload too large.
+#if MBEDTLS_SSL_IN_CONTENT_LEN > MBEDTLS_SSL_MAX_CONTENT_LEN
+#error "Bad configuration - incoming record content should not be larger than MBEDTLS_SSL_MAX_CONTENT_LEN."
 #endif
 
+#if MBEDTLS_SSL_OUT_CONTENT_LEN > MBEDTLS_SSL_MAX_CONTENT_LEN
+#error "Bad configuration - outgoing record content should not be larger than MBEDTLS_SSL_MAX_CONTENT_LEN."
+#endif
+
+#if MBEDTLS_SSL_IN_PAYLOAD_LEN > MBEDTLS_SSL_MAX_CONTENT_LEN + 2048
+#error "Bad configuration - incoming protected record payload too large."
+#endif
+
+#if MBEDTLS_SSL_OUT_PAYLOAD_LEN > MBEDTLS_SSL_MAX_CONTENT_LEN + 2048
+#error "Bad configuration - outgoing protected record payload too large."
+#endif
+
+/* Calculate buffer sizes */
+
 /* Note: Even though the TLS record header is only 5 bytes
    long, we're internally using 8 bytes to store the
    implicit sequence number. */
 #define MBEDTLS_SSL_HEADER_LEN 13
 
-#define MBEDTLS_SSL_BUFFER_LEN  \
-    ( ( MBEDTLS_SSL_HEADER_LEN ) + ( MBEDTLS_SSL_PAYLOAD_LEN ) )
+#define MBEDTLS_SSL_IN_BUFFER_LEN  \
+    ( ( MBEDTLS_SSL_HEADER_LEN ) + ( MBEDTLS_SSL_IN_PAYLOAD_LEN ) )
+
+#define MBEDTLS_SSL_OUT_BUFFER_LEN  \
+    ( ( MBEDTLS_SSL_HEADER_LEN ) + ( MBEDTLS_SSL_OUT_PAYLOAD_LEN ) )
+
+#ifdef MBEDTLS_ZLIB_SUPPORT
+/* Compression buffer holds both IN and OUT buffers, so should be size of the larger */
+#define MBEDTLS_SSL_COMPRESS_BUFFER_LEN (                               \
+        ( MBEDTLS_SSL_IN_BUFFER_LEN > MBEDTLS_SSL_OUT_BUFFER_LEN )      \
+        ? MBEDTLS_SSL_IN_BUFFER_LEN                                     \
+        : MBEDTLS_SSL_OUT_BUFFER_LEN                                    \
+        )
+#endif
 
 /*
  * TLS extension flags (for extensions with outgoing ServerHello content
diff --git a/library/ssl_cli.c b/library/ssl_cli.c
index e537f9d..09d8a0d 100644
--- a/library/ssl_cli.c
+++ b/library/ssl_cli.c
@@ -57,7 +57,7 @@
                                     size_t *olen )
 {
     unsigned char *p = buf;
-    const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN;
+    const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN;
     size_t hostname_len;
 
     *olen = 0;
@@ -127,7 +127,7 @@
                                          size_t *olen )
 {
     unsigned char *p = buf;
-    const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN;
+    const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN;
 
     *olen = 0;
 
@@ -171,7 +171,7 @@
                                                 size_t *olen )
 {
     unsigned char *p = buf;
-    const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN;
+    const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN;
     size_t sig_alg_len = 0;
     const int *md;
 #if defined(MBEDTLS_RSA_C) || defined(MBEDTLS_ECDSA_C)
@@ -256,7 +256,7 @@
                                                      size_t *olen )
 {
     unsigned char *p = buf;
-    const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN;
+    const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN;
     unsigned char *elliptic_curve_list = p + 6;
     size_t elliptic_curve_len = 0;
     const mbedtls_ecp_curve_info *info;
@@ -329,7 +329,7 @@
                                                    size_t *olen )
 {
     unsigned char *p = buf;
-    const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN;
+    const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN;
 
     *olen = 0;
 
@@ -362,7 +362,7 @@
 {
     int ret;
     unsigned char *p = buf;
-    const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN;
+    const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN;
     size_t kkpp_len;
 
     *olen = 0;
@@ -439,7 +439,7 @@
                                                size_t *olen )
 {
     unsigned char *p = buf;
-    const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN;
+    const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN;
 
     *olen = 0;
 
@@ -472,7 +472,7 @@
                                           unsigned char *buf, size_t *olen )
 {
     unsigned char *p = buf;
-    const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN;
+    const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN;
 
     *olen = 0;
 
@@ -504,7 +504,7 @@
                                        unsigned char *buf, size_t *olen )
 {
     unsigned char *p = buf;
-    const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN;
+    const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN;
 
     *olen = 0;
 
@@ -538,7 +538,7 @@
                                        unsigned char *buf, size_t *olen )
 {
     unsigned char *p = buf;
-    const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN;
+    const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN;
 
     *olen = 0;
 
@@ -572,7 +572,7 @@
                                           unsigned char *buf, size_t *olen )
 {
     unsigned char *p = buf;
-    const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN;
+    const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN;
     size_t tlen = ssl->session_negotiate->ticket_len;
 
     *olen = 0;
@@ -616,7 +616,7 @@
                                 unsigned char *buf, size_t *olen )
 {
     unsigned char *p = buf;
-    const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN;
+    const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN;
     size_t alpnlen = 0;
     const char **cur;
 
@@ -2117,7 +2117,7 @@
     size_t len_bytes = ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 ? 0 : 2;
     unsigned char *p = ssl->handshake->premaster + pms_offset;
 
-    if( offset + len_bytes > MBEDTLS_SSL_MAX_CONTENT_LEN )
+    if( offset + len_bytes > MBEDTLS_SSL_OUT_CONTENT_LEN )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "buffer too small for encrypted pms" ) );
         return( MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL );
@@ -2160,7 +2160,7 @@
     if( ( ret = mbedtls_pk_encrypt( &ssl->session_negotiate->peer_cert->pk,
                             p, ssl->handshake->pmslen,
                             ssl->out_msg + offset + len_bytes, olen,
-                            MBEDTLS_SSL_MAX_CONTENT_LEN - offset - len_bytes,
+                            MBEDTLS_SSL_OUT_CONTENT_LEN - offset - len_bytes,
                             ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 )
     {
         MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_rsa_pkcs1_encrypt", ret );
@@ -2926,7 +2926,7 @@
         i = 4;
         n = ssl->conf->psk_identity_len;
 
-        if( i + 2 + n > MBEDTLS_SSL_MAX_CONTENT_LEN )
+        if( i + 2 + n > MBEDTLS_SSL_OUT_CONTENT_LEN )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "psk identity too long or "
                                         "SSL buffer too short" ) );
@@ -2962,7 +2962,7 @@
              */
             n = ssl->handshake->dhm_ctx.len;
 
-            if( i + 2 + n > MBEDTLS_SSL_MAX_CONTENT_LEN )
+            if( i + 2 + n > MBEDTLS_SSL_OUT_CONTENT_LEN )
             {
                 MBEDTLS_SSL_DEBUG_MSG( 1, ( "psk identity or DHM size too long"
                                             " or SSL buffer too short" ) );
@@ -2991,7 +2991,7 @@
              * ClientECDiffieHellmanPublic public;
              */
             ret = mbedtls_ecdh_make_public( &ssl->handshake->ecdh_ctx, &n,
-                    &ssl->out_msg[i], MBEDTLS_SSL_MAX_CONTENT_LEN - i,
+                    &ssl->out_msg[i], MBEDTLS_SSL_OUT_CONTENT_LEN - i,
                     ssl->conf->f_rng, ssl->conf->p_rng );
             if( ret != 0 )
             {
@@ -3032,7 +3032,7 @@
         i = 4;
 
         ret = mbedtls_ecjpake_write_round_two( &ssl->handshake->ecjpake_ctx,
-                ssl->out_msg + i, MBEDTLS_SSL_MAX_CONTENT_LEN - i, &n,
+                ssl->out_msg + i, MBEDTLS_SSL_OUT_CONTENT_LEN - i, &n,
                 ssl->conf->f_rng, ssl->conf->p_rng );
         if( ret != 0 )
         {
diff --git a/library/ssl_srv.c b/library/ssl_srv.c
index 0ccab58..f81bdbf 100644
--- a/library/ssl_srv.c
+++ b/library/ssl_srv.c
@@ -1303,7 +1303,7 @@
     else
 #endif
     {
-        if( msg_len > MBEDTLS_SSL_MAX_CONTENT_LEN )
+        if( msg_len > MBEDTLS_SSL_IN_CONTENT_LEN )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad client hello message" ) );
             return( MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO );
@@ -2235,7 +2235,7 @@
 {
     int ret;
     unsigned char *p = buf;
-    const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN;
+    const unsigned char *end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN;
     size_t kkpp_len;
 
     *olen = 0;
@@ -2342,7 +2342,7 @@
     cookie_len_byte = p++;
 
     if( ( ret = ssl->conf->f_cookie_write( ssl->conf->p_cookie,
-                                     &p, ssl->out_buf + MBEDTLS_SSL_BUFFER_LEN,
+                                     &p, ssl->out_buf + MBEDTLS_SSL_OUT_BUFFER_LEN,
                                      ssl->cli_id, ssl->cli_id_len ) ) != 0 )
     {
         MBEDTLS_SSL_DEBUG_RET( 1, "f_cookie_write", ret );
@@ -2638,7 +2638,7 @@
     size_t dn_size, total_dn_size; /* excluding length bytes */
     size_t ct_len, sa_len; /* including length bytes */
     unsigned char *buf, *p;
-    const unsigned char * const end = ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN;
+    const unsigned char * const end = ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN;
     const mbedtls_x509_crt *crt;
     int authmode;
 
@@ -2839,7 +2839,7 @@
      * ssl_write_server_key_exchange also takes care of incrementing
      * ssl->out_msglen. */
     unsigned char *sig_start = ssl->out_msg + ssl->out_msglen + 2;
-    size_t sig_max_len = ( ssl->out_buf + MBEDTLS_SSL_MAX_CONTENT_LEN
+    size_t sig_max_len = ( ssl->out_buf + MBEDTLS_SSL_OUT_CONTENT_LEN
                            - sig_start );
     int ret = ssl->conf->f_async_resume( ssl,
                                          sig_start, signature_len, sig_max_len );
@@ -2893,7 +2893,7 @@
         ret = mbedtls_ecjpake_write_round_two(
             &ssl->handshake->ecjpake_ctx,
             ssl->out_msg + ssl->out_msglen,
-            MBEDTLS_SSL_MAX_CONTENT_LEN - ssl->out_msglen, &len,
+            MBEDTLS_SSL_OUT_CONTENT_LEN - ssl->out_msglen, &len,
             ssl->conf->f_rng, ssl->conf->p_rng );
         if( ret != 0 )
         {
@@ -3020,7 +3020,7 @@
         if( ( ret = mbedtls_ecdh_make_params(
                   &ssl->handshake->ecdh_ctx, &len,
                   ssl->out_msg + ssl->out_msglen,
-                  MBEDTLS_SSL_MAX_CONTENT_LEN - ssl->out_msglen,
+                  MBEDTLS_SSL_OUT_CONTENT_LEN - ssl->out_msglen,
                   ssl->conf->f_rng, ssl->conf->p_rng ) ) != 0 )
         {
             MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ecdh_make_params", ret );
@@ -4171,7 +4171,7 @@
     if( ( ret = ssl->conf->f_ticket_write( ssl->conf->p_ticket,
                                 ssl->session_negotiate,
                                 ssl->out_msg + 10,
-                                ssl->out_msg + MBEDTLS_SSL_MAX_CONTENT_LEN,
+                                ssl->out_msg + MBEDTLS_SSL_OUT_CONTENT_LEN,
                                 &tlen, &lifetime ) ) != 0 )
     {
         MBEDTLS_SSL_DEBUG_RET( 1, "mbedtls_ssl_ticket_write", ret );
diff --git a/library/ssl_tls.c b/library/ssl_tls.c
index bc63c6e..185f35a 100644
--- a/library/ssl_tls.c
+++ b/library/ssl_tls.c
@@ -141,14 +141,24 @@
  *    } MaxFragmentLength;
  * and we add 0 -> extension unused
  */
-static unsigned int mfl_code_to_length[MBEDTLS_SSL_MAX_FRAG_LEN_INVALID] =
+static unsigned int ssl_mfl_code_to_length( int mfl )
 {
-    MBEDTLS_SSL_MAX_CONTENT_LEN,    /* MBEDTLS_SSL_MAX_FRAG_LEN_NONE */
-    512,                    /* MBEDTLS_SSL_MAX_FRAG_LEN_512  */
-    1024,                   /* MBEDTLS_SSL_MAX_FRAG_LEN_1024 */
-    2048,                   /* MBEDTLS_SSL_MAX_FRAG_LEN_2048 */
-    4096,                   /* MBEDTLS_SSL_MAX_FRAG_LEN_4096 */
-};
+    switch( mfl )
+    {
+    case MBEDTLS_SSL_MAX_FRAG_LEN_NONE:
+        return ( MBEDTLS_TLS_EXT_ADV_CONTENT_LEN );
+    case MBEDTLS_SSL_MAX_FRAG_LEN_512:
+        return 512;
+    case MBEDTLS_SSL_MAX_FRAG_LEN_1024:
+        return 1024;
+    case MBEDTLS_SSL_MAX_FRAG_LEN_2048:
+        return 2048;
+    case MBEDTLS_SSL_MAX_FRAG_LEN_4096:
+        return 4096;
+    default:
+        return ( MBEDTLS_TLS_EXT_ADV_CONTENT_LEN );
+    }
+}
 #endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
 
 #if defined(MBEDTLS_SSL_CLI_C)
@@ -956,11 +966,11 @@
         if( ssl->compress_buf == NULL )
         {
             MBEDTLS_SSL_DEBUG_MSG( 3, ( "Allocating compression buffer" ) );
-            ssl->compress_buf = mbedtls_calloc( 1, MBEDTLS_SSL_BUFFER_LEN );
+            ssl->compress_buf = mbedtls_calloc( 1, MBEDTLS_SSL_COMPRESS_BUFFER_LEN );
             if( ssl->compress_buf == NULL )
             {
                 MBEDTLS_SSL_DEBUG_MSG( 1, ( "alloc(%d bytes) failed",
-                                    MBEDTLS_SSL_BUFFER_LEN ) );
+                                    MBEDTLS_SSL_COMPRESS_BUFFER_LEN ) );
                 return( MBEDTLS_ERR_SSL_ALLOC_FAILED );
             }
         }
@@ -1297,11 +1307,11 @@
     MBEDTLS_SSL_DEBUG_BUF( 4, "before encrypt: output payload",
                       ssl->out_msg, ssl->out_msglen );
 
-    if( ssl->out_msglen > MBEDTLS_SSL_MAX_CONTENT_LEN )
+    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_MAX_CONTENT_LEN ) );
+                                    MBEDTLS_SSL_OUT_CONTENT_LEN ) );
         return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
     }
 
@@ -1906,14 +1916,14 @@
              * Padding is guaranteed to be incorrect if:
              *   1. padlen >= ssl->in_msglen
              *
-             *   2. padding_idx >= MBEDTLS_SSL_MAX_CONTENT_LEN +
+             *   2. padding_idx >= MBEDTLS_SSL_IN_CONTENT_LEN +
              *                     ssl->transform_in->maclen
              *
              * In both cases we reset padding_idx to a safe value (0) to
              * prevent out-of-buffer reads.
              */
             correct &= ( ssl->in_msglen >= padlen + 1 );
-            correct &= ( padding_idx < MBEDTLS_SSL_MAX_CONTENT_LEN +
+            correct &= ( padding_idx < MBEDTLS_SSL_IN_CONTENT_LEN +
                                        ssl->transform_in->maclen );
 
             padding_idx *= correct;
@@ -2126,7 +2136,7 @@
     ssl->transform_out->ctx_deflate.next_in = msg_pre;
     ssl->transform_out->ctx_deflate.avail_in = len_pre;
     ssl->transform_out->ctx_deflate.next_out = msg_post;
-    ssl->transform_out->ctx_deflate.avail_out = MBEDTLS_SSL_BUFFER_LEN - bytes_written;
+    ssl->transform_out->ctx_deflate.avail_out = MBEDTLS_SSL_OUT_BUFFER_LEN - bytes_written;
 
     ret = deflate( &ssl->transform_out->ctx_deflate, Z_SYNC_FLUSH );
     if( ret != Z_OK )
@@ -2135,7 +2145,7 @@
         return( MBEDTLS_ERR_SSL_COMPRESSION_FAILED );
     }
 
-    ssl->out_msglen = MBEDTLS_SSL_BUFFER_LEN -
+    ssl->out_msglen = MBEDTLS_SSL_OUT_BUFFER_LEN -
                       ssl->transform_out->ctx_deflate.avail_out - bytes_written;
 
     MBEDTLS_SSL_DEBUG_MSG( 3, ( "after compression: msglen = %d, ",
@@ -2173,7 +2183,7 @@
     ssl->transform_in->ctx_inflate.next_in = msg_pre;
     ssl->transform_in->ctx_inflate.avail_in = len_pre;
     ssl->transform_in->ctx_inflate.next_out = msg_post;
-    ssl->transform_in->ctx_inflate.avail_out = MBEDTLS_SSL_BUFFER_LEN -
+    ssl->transform_in->ctx_inflate.avail_out = MBEDTLS_SSL_IN_BUFFER_LEN -
                                                header_bytes;
 
     ret = inflate( &ssl->transform_in->ctx_inflate, Z_SYNC_FLUSH );
@@ -2183,7 +2193,7 @@
         return( MBEDTLS_ERR_SSL_COMPRESSION_FAILED );
     }
 
-    ssl->in_msglen = MBEDTLS_SSL_BUFFER_LEN -
+    ssl->in_msglen = MBEDTLS_SSL_IN_BUFFER_LEN -
                      ssl->transform_in->ctx_inflate.avail_out - header_bytes;
 
     MBEDTLS_SSL_DEBUG_MSG( 3, ( "after decompression: msglen = %d, ",
@@ -2258,7 +2268,7 @@
         return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
     }
 
-    if( nb_want > MBEDTLS_SSL_BUFFER_LEN - (size_t)( ssl->in_hdr - ssl->in_buf ) )
+    if( nb_want > MBEDTLS_SSL_IN_BUFFER_LEN - (size_t)( ssl->in_hdr - ssl->in_buf ) )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "requesting more data than fits" ) );
         return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
@@ -2344,7 +2354,7 @@
         }
         else
         {
-            len = MBEDTLS_SSL_BUFFER_LEN - ( ssl->in_hdr - ssl->in_buf );
+            len = MBEDTLS_SSL_IN_BUFFER_LEN - ( ssl->in_hdr - ssl->in_buf );
 
             if( ssl->state != MBEDTLS_SSL_HANDSHAKE_OVER )
                 timeout = ssl->handshake->retransmit_timeout;
@@ -2798,12 +2808,12 @@
         if( ssl->conf->transport == MBEDTLS_SSL_TRANSPORT_DATAGRAM )
         {
             /* Make room for the additional DTLS fields */
-            if( MBEDTLS_SSL_MAX_CONTENT_LEN - ssl->out_msglen < 8 )
+            if( MBEDTLS_SSL_OUT_CONTENT_LEN - ssl->out_msglen < 8 )
             {
                 MBEDTLS_SSL_DEBUG_MSG( 1, ( "DTLS handshake message too large: "
                               "size %u, maximum %u",
                                (unsigned) ( ssl->in_hslen - 4 ),
-                               (unsigned) ( MBEDTLS_SSL_MAX_CONTENT_LEN - 12 ) ) );
+                               (unsigned) ( MBEDTLS_SSL_OUT_CONTENT_LEN - 12 ) ) );
                 return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
             }
 
@@ -3016,7 +3026,7 @@
         MBEDTLS_SSL_DEBUG_MSG( 2, ( "initialize reassembly, total length = %d",
                             msg_len ) );
 
-        if( ssl->in_hslen > MBEDTLS_SSL_MAX_CONTENT_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 );
@@ -3120,7 +3130,7 @@
         ssl->next_record_offset = new_remain - ssl->in_hdr;
         ssl->in_left = ssl->next_record_offset + remain_len;
 
-        if( ssl->in_left > MBEDTLS_SSL_BUFFER_LEN -
+        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" ) );
@@ -3496,7 +3506,7 @@
             ssl->conf->p_cookie,
             ssl->cli_id, ssl->cli_id_len,
             ssl->in_buf, ssl->in_left,
-            ssl->out_buf, MBEDTLS_SSL_MAX_CONTENT_LEN, &len );
+            ssl->out_buf, MBEDTLS_SSL_OUT_CONTENT_LEN, &len );
 
     MBEDTLS_SSL_DEBUG_RET( 2, "ssl_check_dtls_clihlo_cookie", ret );
 
@@ -3593,7 +3603,7 @@
     }
 
     /* Check length against the size of our buffer */
-    if( ssl->in_msglen > MBEDTLS_SSL_BUFFER_LEN
+    if( ssl->in_msglen > MBEDTLS_SSL_IN_BUFFER_LEN
                          - (size_t)( ssl->in_msg - ssl->in_buf ) )
     {
         MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad message length" ) );
@@ -3687,7 +3697,7 @@
     if( ssl->transform_in == NULL )
     {
         if( ssl->in_msglen < 1 ||
-            ssl->in_msglen > MBEDTLS_SSL_MAX_CONTENT_LEN )
+            ssl->in_msglen > MBEDTLS_SSL_IN_CONTENT_LEN )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad message length" ) );
             return( MBEDTLS_ERR_SSL_INVALID_RECORD );
@@ -3703,7 +3713,7 @@
 
 #if defined(MBEDTLS_SSL_PROTO_SSL3)
         if( ssl->minor_ver == MBEDTLS_SSL_MINOR_VERSION_0 &&
-            ssl->in_msglen > ssl->transform_in->minlen + MBEDTLS_SSL_MAX_CONTENT_LEN )
+            ssl->in_msglen > ssl->transform_in->minlen + MBEDTLS_SSL_IN_CONTENT_LEN )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad message length" ) );
             return( MBEDTLS_ERR_SSL_INVALID_RECORD );
@@ -3716,7 +3726,7 @@
          */
         if( ssl->minor_ver >= MBEDTLS_SSL_MINOR_VERSION_1 &&
             ssl->in_msglen > ssl->transform_in->minlen +
-                             MBEDTLS_SSL_MAX_CONTENT_LEN + 256 )
+                             MBEDTLS_SSL_IN_CONTENT_LEN + 256 )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad message length" ) );
             return( MBEDTLS_ERR_SSL_INVALID_RECORD );
@@ -3764,7 +3774,7 @@
         MBEDTLS_SSL_DEBUG_BUF( 4, "input payload after decrypt",
                        ssl->in_msg, ssl->in_msglen );
 
-        if( ssl->in_msglen > MBEDTLS_SSL_MAX_CONTENT_LEN )
+        if( ssl->in_msglen > MBEDTLS_SSL_IN_CONTENT_LEN )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "bad message length" ) );
             return( MBEDTLS_ERR_SSL_INVALID_RECORD );
@@ -4325,10 +4335,10 @@
     while( crt != NULL )
     {
         n = crt->raw.len;
-        if( n > MBEDTLS_SSL_MAX_CONTENT_LEN - 3 - i )
+        if( n > MBEDTLS_SSL_OUT_CONTENT_LEN - 3 - i )
         {
             MBEDTLS_SSL_DEBUG_MSG( 1, ( "certificate too large, %d > %d",
-                           i + 3 + n, MBEDTLS_SSL_MAX_CONTENT_LEN ) );
+                           i + 3 + n, MBEDTLS_SSL_OUT_CONTENT_LEN ) );
             return( MBEDTLS_ERR_SSL_CERTIFICATE_TOO_LARGE );
         }
 
@@ -5662,17 +5672,23 @@
                        const mbedtls_ssl_config *conf )
 {
     int ret;
-    const size_t len = MBEDTLS_SSL_BUFFER_LEN;
 
     ssl->conf = conf;
 
     /*
      * Prepare base structures
      */
-    if( ( ssl-> in_buf = mbedtls_calloc( 1, len ) ) == NULL ||
-        ( ssl->out_buf = mbedtls_calloc( 1, len ) ) == 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", len ) );
+        MBEDTLS_SSL_DEBUG_MSG( 1, ( "alloc(%d bytes) failed", MBEDTLS_SSL_IN_BUFFER_LEN) );
+        return( MBEDTLS_ERR_SSL_ALLOC_FAILED );
+    }
+
+    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 );
@@ -5773,9 +5789,9 @@
     ssl->transform_in = NULL;
     ssl->transform_out = NULL;
 
-    memset( ssl->out_buf, 0, MBEDTLS_SSL_BUFFER_LEN );
+    memset( ssl->out_buf, 0, MBEDTLS_SSL_OUT_BUFFER_LEN );
     if( partial == 0 )
-        memset( ssl->in_buf, 0, MBEDTLS_SSL_BUFFER_LEN );
+        memset( ssl->in_buf, 0, MBEDTLS_SSL_IN_BUFFER_LEN );
 
 #if defined(MBEDTLS_SSL_HW_RECORD_ACCEL)
     if( mbedtls_ssl_hw_record_reset != NULL )
@@ -6100,7 +6116,7 @@
 
     /* Identity len will be encoded on two bytes */
     if( ( psk_identity_len >> 16 ) != 0 ||
-        psk_identity_len > MBEDTLS_SSL_MAX_CONTENT_LEN )
+        psk_identity_len > MBEDTLS_SSL_OUT_CONTENT_LEN )
     {
         return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
     }
@@ -6401,7 +6417,7 @@
 int mbedtls_ssl_conf_max_frag_len( mbedtls_ssl_config *conf, unsigned char mfl_code )
 {
     if( mfl_code >= MBEDTLS_SSL_MAX_FRAG_LEN_INVALID ||
-        mfl_code_to_length[mfl_code] > MBEDTLS_SSL_MAX_CONTENT_LEN )
+        ssl_mfl_code_to_length( mfl_code ) > MBEDTLS_TLS_EXT_ADV_CONTENT_LEN )
     {
         return( MBEDTLS_ERR_SSL_BAD_INPUT_DATA );
     }
@@ -6679,15 +6695,15 @@
     /*
      * Assume mfl_code is correct since it was checked when set
      */
-    max_len = mfl_code_to_length[ssl->conf->mfl_code];
+    max_len = ssl_mfl_code_to_length( ssl->conf->mfl_code );
 
     /*
      * Check if a smaller max length was negotiated
      */
     if( ssl->session_out != NULL &&
-        mfl_code_to_length[ssl->session_out->mfl_code] < max_len )
+        ssl_mfl_code_to_length( ssl->session_out->mfl_code ) < max_len )
     {
-        max_len = mfl_code_to_length[ssl->session_out->mfl_code];
+        max_len = ssl_mfl_code_to_length( ssl->session_out->mfl_code );
     }
 
     return max_len;
@@ -7249,7 +7265,7 @@
 #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_MAX_CONTENT_LEN;
+    size_t max_len = MBEDTLS_SSL_OUT_CONTENT_LEN;
 #endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
     if( len > max_len )
     {
@@ -7562,20 +7578,20 @@
 
     if( ssl->out_buf != NULL )
     {
-        mbedtls_platform_zeroize( ssl->out_buf, MBEDTLS_SSL_BUFFER_LEN );
+        mbedtls_platform_zeroize( ssl->out_buf, MBEDTLS_SSL_OUT_BUFFER_LEN );
         mbedtls_free( ssl->out_buf );
     }
 
     if( ssl->in_buf != NULL )
     {
-        mbedtls_platform_zeroize( ssl->in_buf, MBEDTLS_SSL_BUFFER_LEN );
+        mbedtls_platform_zeroize( ssl->in_buf, MBEDTLS_SSL_IN_BUFFER_LEN );
         mbedtls_free( ssl->in_buf );
     }
 
 #if defined(MBEDTLS_ZLIB_SUPPORT)
     if( ssl->compress_buf != NULL )
     {
-        mbedtls_platform_zeroize( ssl->compress_buf, MBEDTLS_SSL_BUFFER_LEN );
+        mbedtls_platform_zeroize( ssl->compress_buf, MBEDTLS_SSL_COMPRESS_BUFFER_LEN );
         mbedtls_free( ssl->compress_buf );
     }
 #endif
diff --git a/tests/scripts/all.sh b/tests/scripts/all.sh
index ded43f9..1e1cf35 100755
--- a/tests/scripts/all.sh
+++ b/tests/scripts/all.sh
@@ -526,6 +526,28 @@
 msg "test: RSA_NO_CRT - RSA-related part of compat.sh (ASan build)" # ~ 3 min
 tests/compat.sh -t RSA
 
+msg "build: small SSL_OUT_CONTENT_LEN (ASan build)"
+cleanup
+cp "$CONFIG_H" "$CONFIG_BAK"
+scripts/config.pl set MBEDTLS_SSL_IN_CONTENT_LEN 16384
+scripts/config.pl set MBEDTLS_SSL_OUT_CONTENT_LEN 4096
+CC=gcc cmake -D CMAKE_BUILD_TYPE:String=Asan .
+make
+
+msg "test: small SSL_OUT_CONTENT_LEN - ssl-opt.sh MFL and large packet tests"
+if_build_succeeded tests/ssl-opt.sh -f "Max fragment\|Large packet"
+
+msg "build: small SSL_IN_CONTENT_LEN (ASan build)"
+cleanup
+cp "$CONFIG_H" "$CONFIG_BAK"
+scripts/config.pl set MBEDTLS_SSL_IN_CONTENT_LEN 4096
+scripts/config.pl set MBEDTLS_SSL_OUT_CONTENT_LEN 16384
+CC=gcc cmake -D CMAKE_BUILD_TYPE:String=Asan .
+make
+
+msg "test: small SSL_IN_CONTENT_LEN - ssl-opt.sh MFL tests"
+if_build_succeeded tests/ssl-opt.sh -f "Max fragment"
+
 msg "build: cmake, full config, clang" # ~ 50s
 cleanup
 cp "$CONFIG_H" "$CONFIG_BAK"
@@ -640,6 +662,7 @@
 scripts/config.pl set MBEDTLS_NO_PLATFORM_ENTROPY # uses syscall() on GNU/Linux
 make CC=gcc CFLAGS='-Werror -Wall -Wextra -O0 -std=c99 -pedantic' lib
 
+# Run max fragment length tests with MFL disabled
 msg "build: default config except MFL extension (ASan build)" # ~ 30s
 cleanup
 cp "$CONFIG_H" "$CONFIG_BAK"
@@ -650,6 +673,18 @@
 msg "test: ssl-opt.sh, MFL-related tests"
 if_build_succeeded tests/ssl-opt.sh -f "Max fragment length"
 
+msg "build: no MFL extension, small SSL_OUT_CONTENT_LEN (ASan build)"
+cleanup
+cp "$CONFIG_H" "$CONFIG_BAK"
+scripts/config.pl unset MBEDTLS_SSL_MAX_FRAGMENT_LENGTH
+scripts/config.pl set MBEDTLS_SSL_IN_CONTENT_LEN 16384
+scripts/config.pl set MBEDTLS_SSL_OUT_CONTENT_LEN 4096
+CC=gcc cmake -D CMAKE_BUILD_TYPE:String=Asan .
+make
+
+msg "test: MFL tests (disabled MFL extension case) & large packet tests"
+if_build_succeeded tests/ssl-opt.sh -f "Max fragment length\|Large buffer"
+
 msg "build: default config with  MBEDTLS_TEST_NULL_ENTROPY (ASan build)"
 cleanup
 cp "$CONFIG_H" "$CONFIG_BAK"
diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh
index 91f16e1..9fc91c7 100755
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -21,6 +21,11 @@
 
 set -u
 
+if cd $( dirname $0 ); then :; else
+    echo "cd $( dirname $0 ) failed" >&2
+    exit 1
+fi
+
 # default values, can be overriden by the environment
 : ${P_SRV:=../programs/ssl/ssl_server2}
 : ${P_CLI:=../programs/ssl/ssl_client2}
@@ -178,6 +183,25 @@
     fi
 }
 
+# Calculate the input & output maximum content lengths set in the config
+MAX_CONTENT_LEN=$( ../scripts/config.pl get MBEDTLS_SSL_MAX_CONTENT_LEN || echo "16384")
+MAX_IN_LEN=$( ../scripts/config.pl get MBEDTLS_SSL_IN_CONTENT_LEN || echo "$MAX_CONTENT_LEN")
+MAX_OUT_LEN=$( ../scripts/config.pl get MBEDTLS_SSL_OUT_CONTENT_LEN || echo "$MAX_CONTENT_LEN")
+
+if [ "$MAX_IN_LEN" -lt "$MAX_CONTENT_LEN" ]; then
+    MAX_CONTENT_LEN="$MAX_IN_LEN"
+fi
+if [ "$MAX_OUT_LEN" -lt "$MAX_CONTENT_LEN" ]; then
+    MAX_CONTENT_LEN="$MAX_OUT_LEN"
+fi
+
+# skip the next test if the SSL output buffer is less than 16KB
+requires_full_size_output_buffer() {
+    if [ "$MAX_OUT_LEN" -ne 16384 ]; then
+        SKIP_NEXT="YES"
+    fi
+}
+
 # skip the next test if valgrind is in use
 not_with_valgrind() {
     if [ "$MEMCHECK" -gt 0 ]; then
@@ -626,11 +650,6 @@
 # MAIN
 #
 
-if cd $( dirname $0 ); then :; else
-    echo "cd $( dirname $0 ) failed" >&2
-    exit 1
-fi
-
 get_options "$@"
 
 # sanity checks, avoid an avalanche of errors
@@ -1416,28 +1435,22 @@
 
 # Tests for Max Fragment Length extension
 
-MAX_CONTENT_LEN_EXPECT='16384'
-MAX_CONTENT_LEN_CONFIG=$( ../scripts/config.pl get MBEDTLS_SSL_MAX_CONTENT_LEN)
-
-if [ -n "$MAX_CONTENT_LEN_CONFIG" ] && [ "$MAX_CONTENT_LEN_CONFIG" -ne "$MAX_CONTENT_LEN_EXPECT" ]; then
-    printf "The ${CONFIG_H} file contains a value for the configuration of\n"
-    printf "MBEDTLS_SSL_MAX_CONTENT_LEN that is different from the script’s\n"
-    printf "test value of ${MAX_CONTENT_LEN_EXPECT}. \n"
-    printf "\n"
-    printf "The tests assume this value and if it changes, the tests in this\n"
-    printf "script should also be adjusted.\n"
-    printf "\n"
-
+if [ "$MAX_CONTENT_LEN" -lt "4096" ]; then
+    printf "${CONFIG_H} defines MBEDTLS_SSL_MAX_CONTENT_LEN to be less than 4096. Fragment length tests will fail.\n"
     exit 1
 fi
 
+if [ $MAX_CONTENT_LEN -ne 16384 ]; then
+    printf "Using non-default maximum content length $MAX_CONTENT_LEN\n"
+fi
+
 requires_config_enabled MBEDTLS_SSL_MAX_FRAGMENT_LENGTH
 run_test    "Max fragment length: enabled, default" \
             "$P_SRV debug_level=3" \
             "$P_CLI debug_level=3" \
             0 \
-            -c "Maximum fragment length is 16384" \
-            -s "Maximum fragment length is 16384" \
+            -c "Maximum fragment length is $MAX_CONTENT_LEN" \
+            -s "Maximum fragment length is $MAX_CONTENT_LEN" \
             -C "client hello, adding max_fragment_length extension" \
             -S "found max fragment length extension" \
             -S "server hello, max_fragment_length extension" \
@@ -1446,46 +1459,50 @@
 requires_config_enabled MBEDTLS_SSL_MAX_FRAGMENT_LENGTH
 run_test    "Max fragment length: enabled, default, larger message" \
             "$P_SRV debug_level=3" \
-            "$P_CLI debug_level=3 request_size=16385" \
+            "$P_CLI debug_level=3 request_size=$(( $MAX_CONTENT_LEN + 1))" \
             0 \
-            -c "Maximum fragment length is 16384" \
-            -s "Maximum fragment length is 16384" \
+            -c "Maximum fragment length is $MAX_CONTENT_LEN" \
+            -s "Maximum fragment length is $MAX_CONTENT_LEN" \
             -C "client hello, adding max_fragment_length extension" \
             -S "found max fragment length extension" \
             -S "server hello, max_fragment_length extension" \
             -C "found max_fragment_length extension" \
-            -c "16385 bytes written in 2 fragments" \
-            -s "16384 bytes read" \
+            -c "$(( $MAX_CONTENT_LEN + 1)) bytes written in 2 fragments" \
+            -s "$MAX_CONTENT_LEN bytes read" \
             -s "1 bytes read"
 
 requires_config_enabled MBEDTLS_SSL_MAX_FRAGMENT_LENGTH
 run_test    "Max fragment length, DTLS: enabled, default, larger message" \
             "$P_SRV debug_level=3 dtls=1" \
-            "$P_CLI debug_level=3 dtls=1 request_size=16385" \
+            "$P_CLI debug_level=3 dtls=1 request_size=$(( $MAX_CONTENT_LEN + 1))" \
             1 \
-            -c "Maximum fragment length is 16384" \
-            -s "Maximum fragment length is 16384" \
+            -c "Maximum fragment length is $MAX_CONTENT_LEN" \
+            -s "Maximum fragment length is $MAX_CONTENT_LEN" \
             -C "client hello, adding max_fragment_length extension" \
             -S "found max fragment length extension" \
             -S "server hello, max_fragment_length extension" \
             -C "found max_fragment_length extension" \
             -c "fragment larger than.*maximum "
 
+# Run some tests with MBEDTLS_SSL_MAX_FRAGMENT_LENGTH disabled
+# (session fragment length will be 16384 regardless of mbedtls
+# content length configuration.)
+
 requires_config_disabled MBEDTLS_SSL_MAX_FRAGMENT_LENGTH
 run_test    "Max fragment length: disabled, larger message" \
             "$P_SRV debug_level=3" \
-            "$P_CLI debug_level=3 request_size=16385" \
+            "$P_CLI debug_level=3 request_size=$(( $MAX_CONTENT_LEN + 1))" \
             0 \
             -C "Maximum fragment length is 16384" \
             -S "Maximum fragment length is 16384" \
-            -c "16385 bytes written in 2 fragments" \
-            -s "16384 bytes read" \
+            -c "$(( $MAX_CONTENT_LEN + 1)) bytes written in 2 fragments" \
+            -s "$MAX_CONTENT_LEN bytes read" \
             -s "1 bytes read"
 
 requires_config_disabled MBEDTLS_SSL_MAX_FRAGMENT_LENGTH
 run_test    "Max fragment length DTLS: disabled, larger message" \
             "$P_SRV debug_level=3 dtls=1" \
-            "$P_CLI debug_level=3 dtls=1 request_size=16385" \
+            "$P_CLI debug_level=3 dtls=1 request_size=$(( $MAX_CONTENT_LEN + 1))" \
             1 \
             -C "Maximum fragment length is 16384" \
             -S "Maximum fragment length is 16384" \
@@ -1508,7 +1525,7 @@
             "$P_SRV debug_level=3 max_frag_len=4096" \
             "$P_CLI debug_level=3" \
             0 \
-            -c "Maximum fragment length is 16384" \
+            -c "Maximum fragment length is $MAX_CONTENT_LEN" \
             -s "Maximum fragment length is 4096" \
             -C "client hello, adding max_fragment_length extension" \
             -S "found max fragment length extension" \
@@ -2376,6 +2393,7 @@
     exit 1
 fi
 
+requires_full_size_output_buffer
 run_test    "Authentication: server max_int chain, client default" \
             "$P_SRV crt_file=data_files/dir-maxpath/c09.pem \
                     key_file=data_files/dir-maxpath/09.key" \
@@ -2383,6 +2401,7 @@
             0 \
             -C "X509 - A fatal error occured"
 
+requires_full_size_output_buffer
 run_test    "Authentication: server max_int+1 chain, client default" \
             "$P_SRV crt_file=data_files/dir-maxpath/c10.pem \
                     key_file=data_files/dir-maxpath/10.key" \
@@ -2390,6 +2409,7 @@
             1 \
             -c "X509 - A fatal error occured"
 
+requires_full_size_output_buffer
 run_test    "Authentication: server max_int+1 chain, client optional" \
             "$P_SRV crt_file=data_files/dir-maxpath/c10.pem \
                     key_file=data_files/dir-maxpath/10.key" \
@@ -2398,6 +2418,7 @@
             1 \
             -c "X509 - A fatal error occured"
 
+requires_full_size_output_buffer
 run_test    "Authentication: server max_int+1 chain, client none" \
             "$P_SRV crt_file=data_files/dir-maxpath/c10.pem \
                     key_file=data_files/dir-maxpath/10.key" \
@@ -2406,6 +2427,7 @@
             0 \
             -C "X509 - A fatal error occured"
 
+requires_full_size_output_buffer
 run_test    "Authentication: client max_int+1 chain, server default" \
             "$P_SRV ca_file=data_files/dir-maxpath/00.crt" \
             "$P_CLI crt_file=data_files/dir-maxpath/c10.pem \
@@ -2413,6 +2435,7 @@
             0 \
             -S "X509 - A fatal error occured"
 
+requires_full_size_output_buffer
 run_test    "Authentication: client max_int+1 chain, server optional" \
             "$P_SRV ca_file=data_files/dir-maxpath/00.crt auth_mode=optional" \
             "$P_CLI crt_file=data_files/dir-maxpath/c10.pem \
@@ -2420,6 +2443,7 @@
             1 \
             -s "X509 - A fatal error occured"
 
+requires_full_size_output_buffer
 run_test    "Authentication: client max_int+1 chain, server required" \
             "$P_SRV ca_file=data_files/dir-maxpath/00.crt auth_mode=required" \
             "$P_CLI crt_file=data_files/dir-maxpath/c10.pem \
@@ -2427,6 +2451,7 @@
             1 \
             -s "X509 - A fatal error occured"
 
+requires_full_size_output_buffer
 run_test    "Authentication: client max_int chain, server required" \
             "$P_SRV ca_file=data_files/dir-maxpath/00.crt auth_mode=required" \
             "$P_CLI crt_file=data_files/dir-maxpath/c09.pem \
@@ -3970,14 +3995,19 @@
 
 # Test for large packets
 
+# How many fragments do we expect to write $1 bytes?
+fragments_for_write() {
+    echo "$(( ( $1 + $MAX_OUT_LEN - 1 ) / $MAX_OUT_LEN ))"
+}
+
 requires_config_enabled MBEDTLS_SSL_PROTO_SSL3
 run_test    "Large packet SSLv3 BlockCipher" \
             "$P_SRV min_version=ssl3" \
             "$P_CLI request_size=16384 force_version=ssl3 recsplit=0 \
              force_ciphersuite=TLS-RSA-WITH-AES-256-CBC-SHA" \
             0 \
-            -c "16384 bytes written in 1 fragments" \
-            -s "Read from client: 16384 bytes read"
+            -c "16384 bytes written in $(fragments_for_write 16384) fragments" \
+            -s "Read from client: $MAX_CONTENT_LEN bytes read"
 
 requires_config_enabled MBEDTLS_SSL_PROTO_SSL3
 run_test    "Large packet SSLv3 StreamCipher" \
@@ -3985,23 +4015,23 @@
             "$P_CLI request_size=16384 force_version=ssl3 \
              force_ciphersuite=TLS-RSA-WITH-RC4-128-SHA" \
             0 \
-            -c "16384 bytes written in 1 fragments" \
-            -s "Read from client: 16384 bytes read"
+            -c "16384 bytes written in $(fragments_for_write 16384) fragments" \
+            -s "Read from client: $MAX_CONTENT_LEN bytes read"
 
 run_test    "Large packet TLS 1.0 BlockCipher" \
             "$P_SRV" \
             "$P_CLI request_size=16384 force_version=tls1 recsplit=0 \
              force_ciphersuite=TLS-RSA-WITH-AES-256-CBC-SHA" \
             0 \
-            -c "16384 bytes written in 1 fragments" \
-            -s "Read from client: 16384 bytes read"
+            -c "16384 bytes written in $(fragments_for_write 16384) fragments" \
+            -s "Read from client: $MAX_CONTENT_LEN bytes read"
 
 run_test    "Large packet TLS 1.0 BlockCipher, without EtM" \
             "$P_SRV" \
             "$P_CLI request_size=16384 force_version=tls1 etm=0 recsplit=0 \
              force_ciphersuite=TLS-RSA-WITH-AES-256-CBC-SHA" \
             0 \
-            -s "Read from client: 16384 bytes read"
+            -s "Read from client: $MAX_CONTENT_LEN bytes read"
 
 requires_config_enabled MBEDTLS_SSL_TRUNCATED_HMAC
 run_test    "Large packet TLS 1.0 BlockCipher, truncated MAC" \
@@ -4009,8 +4039,8 @@
             "$P_CLI request_size=16384 force_version=tls1 recsplit=0 \
              force_ciphersuite=TLS-RSA-WITH-AES-256-CBC-SHA trunc_hmac=1" \
             0 \
-            -c "16384 bytes written in 1 fragments" \
-            -s "Read from client: 16384 bytes read"
+            -c "16384 bytes written in $(fragments_for_write 16384) fragments" \
+            -s "Read from client: $MAX_CONTENT_LEN bytes read"
 
 requires_config_enabled MBEDTLS_SSL_TRUNCATED_HMAC
 run_test    "Large packet TLS 1.0 BlockCipher, without EtM, truncated MAC" \
@@ -4018,21 +4048,21 @@
             "$P_CLI request_size=16384 force_version=tls1 etm=0 recsplit=0 \
              force_ciphersuite=TLS-RSA-WITH-AES-256-CBC-SHA trunc_hmac=1" \
             0 \
-            -s "Read from client: 16384 bytes read"
+            -s "Read from client: $MAX_CONTENT_LEN bytes read"
 
 run_test    "Large packet TLS 1.0 StreamCipher" \
             "$P_SRV arc4=1 force_ciphersuite=TLS-RSA-WITH-RC4-128-SHA" \
             "$P_CLI request_size=16384 force_version=tls1 \
              force_ciphersuite=TLS-RSA-WITH-RC4-128-SHA" \
             0 \
-            -s "Read from client: 16384 bytes read"
+            -s "Read from client: $MAX_CONTENT_LEN bytes read"
 
 run_test    "Large packet TLS 1.0 StreamCipher, without EtM" \
             "$P_SRV arc4=1 force_ciphersuite=TLS-RSA-WITH-RC4-128-SHA" \
             "$P_CLI request_size=16384 force_version=tls1 \
              force_ciphersuite=TLS-RSA-WITH-RC4-128-SHA etm=0" \
             0 \
-            -s "Read from client: 16384 bytes read"
+            -s "Read from client: $MAX_CONTENT_LEN bytes read"
 
 requires_config_enabled MBEDTLS_SSL_TRUNCATED_HMAC
 run_test    "Large packet TLS 1.0 StreamCipher, truncated MAC" \
@@ -4040,7 +4070,7 @@
             "$P_CLI request_size=16384 force_version=tls1 \
              force_ciphersuite=TLS-RSA-WITH-RC4-128-SHA trunc_hmac=1" \
             0 \
-            -s "Read from client: 16384 bytes read"
+            -s "Read from client: $MAX_CONTENT_LEN bytes read"
 
 requires_config_enabled MBEDTLS_SSL_TRUNCATED_HMAC
 run_test    "Large packet TLS 1.0 StreamCipher, without EtM, truncated MAC" \
@@ -4048,23 +4078,23 @@
             "$P_CLI request_size=16384 force_version=tls1 \
              force_ciphersuite=TLS-RSA-WITH-RC4-128-SHA trunc_hmac=1 etm=0" \
             0 \
-            -c "16384 bytes written in 1 fragments" \
-            -s "Read from client: 16384 bytes read"
+            -c "16384 bytes written in $(fragments_for_write 16384) fragments" \
+            -s "Read from client: $MAX_CONTENT_LEN bytes read"
 
 run_test    "Large packet TLS 1.1 BlockCipher" \
             "$P_SRV" \
             "$P_CLI request_size=16384 force_version=tls1_1 \
              force_ciphersuite=TLS-RSA-WITH-AES-256-CBC-SHA" \
             0 \
-            -c "16384 bytes written in 1 fragments" \
-            -s "Read from client: 16384 bytes read"
+            -c "16384 bytes written in $(fragments_for_write 16384) fragments" \
+            -s "Read from client: $MAX_CONTENT_LEN bytes read"
 
 run_test    "Large packet TLS 1.1 BlockCipher, without EtM" \
             "$P_SRV" \
             "$P_CLI request_size=16384 force_version=tls1_1 etm=0 \
              force_ciphersuite=TLS-RSA-WITH-AES-256-CBC-SHA" \
             0 \
-            -s "Read from client: 16384 bytes read"
+            -s "Read from client: $MAX_CONTENT_LEN bytes read"
 
 requires_config_enabled MBEDTLS_SSL_TRUNCATED_HMAC
 run_test    "Large packet TLS 1.1 BlockCipher, truncated MAC" \
@@ -4072,7 +4102,7 @@
             "$P_CLI request_size=16384 force_version=tls1_1 \
              force_ciphersuite=TLS-RSA-WITH-AES-256-CBC-SHA trunc_hmac=1" \
             0 \
-            -s "Read from client: 16384 bytes read"
+            -s "Read from client: $MAX_CONTENT_LEN bytes read"
 
 requires_config_enabled MBEDTLS_SSL_TRUNCATED_HMAC
 run_test    "Large packet TLS 1.1 BlockCipher, without EtM, truncated MAC" \
@@ -4080,23 +4110,23 @@
             "$P_CLI request_size=16384 force_version=tls1_1 \
              force_ciphersuite=TLS-RSA-WITH-AES-256-CBC-SHA trunc_hmac=1 etm=0" \
             0 \
-            -s "Read from client: 16384 bytes read"
+            -s "Read from client: $MAX_CONTENT_LEN bytes read"
 
 run_test    "Large packet TLS 1.1 StreamCipher" \
             "$P_SRV arc4=1 force_ciphersuite=TLS-RSA-WITH-RC4-128-SHA" \
             "$P_CLI request_size=16384 force_version=tls1_1 \
              force_ciphersuite=TLS-RSA-WITH-RC4-128-SHA" \
             0 \
-            -c "16384 bytes written in 1 fragments" \
-            -s "Read from client: 16384 bytes read"
+            -c "16384 bytes written in $(fragments_for_write 16384) fragments" \
+            -s "Read from client: $MAX_CONTENT_LEN bytes read"
 
 run_test    "Large packet TLS 1.1 StreamCipher, without EtM" \
             "$P_SRV arc4=1 force_ciphersuite=TLS-RSA-WITH-RC4-128-SHA" \
             "$P_CLI request_size=16384 force_version=tls1_1 \
              force_ciphersuite=TLS-RSA-WITH-RC4-128-SHA etm=0" \
             0 \
-            -c "16384 bytes written in 1 fragments" \
-            -s "Read from client: 16384 bytes read"
+            -c "16384 bytes written in $(fragments_for_write 16384) fragments" \
+            -s "Read from client: $MAX_CONTENT_LEN bytes read"
 
 requires_config_enabled MBEDTLS_SSL_TRUNCATED_HMAC
 run_test    "Large packet TLS 1.1 StreamCipher, truncated MAC" \
@@ -4104,7 +4134,7 @@
             "$P_CLI request_size=16384 force_version=tls1_1 \
              force_ciphersuite=TLS-RSA-WITH-RC4-128-SHA trunc_hmac=1" \
             0 \
-            -s "Read from client: 16384 bytes read"
+            -s "Read from client: $MAX_CONTENT_LEN bytes read"
 
 requires_config_enabled MBEDTLS_SSL_TRUNCATED_HMAC
 run_test    "Large packet TLS 1.1 StreamCipher, without EtM, truncated MAC" \
@@ -4112,31 +4142,31 @@
             "$P_CLI request_size=16384 force_version=tls1_1 \
              force_ciphersuite=TLS-RSA-WITH-RC4-128-SHA trunc_hmac=1 etm=0" \
             0 \
-            -c "16384 bytes written in 1 fragments" \
-            -s "Read from client: 16384 bytes read"
+            -c "16384 bytes written in $(fragments_for_write 16384) fragments" \
+            -s "Read from client: $MAX_CONTENT_LEN bytes read"
 
 run_test    "Large packet TLS 1.2 BlockCipher" \
             "$P_SRV" \
             "$P_CLI request_size=16384 force_version=tls1_2 \
              force_ciphersuite=TLS-RSA-WITH-AES-256-CBC-SHA" \
             0 \
-            -c "16384 bytes written in 1 fragments" \
-            -s "Read from client: 16384 bytes read"
+            -c "16384 bytes written in $(fragments_for_write 16384) fragments" \
+            -s "Read from client: $MAX_CONTENT_LEN bytes read"
 
 run_test    "Large packet TLS 1.2 BlockCipher, without EtM" \
             "$P_SRV" \
             "$P_CLI request_size=16384 force_version=tls1_2 etm=0 \
              force_ciphersuite=TLS-RSA-WITH-AES-256-CBC-SHA" \
             0 \
-            -s "Read from client: 16384 bytes read"
+            -s "Read from client: $MAX_CONTENT_LEN bytes read"
 
 run_test    "Large packet TLS 1.2 BlockCipher larger MAC" \
             "$P_SRV" \
             "$P_CLI request_size=16384 force_version=tls1_2 \
              force_ciphersuite=TLS-ECDHE-RSA-WITH-AES-256-CBC-SHA384" \
             0 \
-            -c "16384 bytes written in 1 fragments" \
-            -s "Read from client: 16384 bytes read"
+            -c "16384 bytes written in $(fragments_for_write 16384) fragments" \
+            -s "Read from client: $MAX_CONTENT_LEN bytes read"
 
 requires_config_enabled MBEDTLS_SSL_TRUNCATED_HMAC
 run_test    "Large packet TLS 1.2 BlockCipher, truncated MAC" \
@@ -4144,7 +4174,7 @@
             "$P_CLI request_size=16384 force_version=tls1_2 \
              force_ciphersuite=TLS-RSA-WITH-AES-256-CBC-SHA trunc_hmac=1" \
             0 \
-            -s "Read from client: 16384 bytes read"
+            -s "Read from client: $MAX_CONTENT_LEN bytes read"
 
 requires_config_enabled MBEDTLS_SSL_TRUNCATED_HMAC
 run_test    "Large packet TLS 1.2 BlockCipher, without EtM, truncated MAC" \
@@ -4152,23 +4182,23 @@
             "$P_CLI request_size=16384 force_version=tls1_2 \
              force_ciphersuite=TLS-RSA-WITH-AES-256-CBC-SHA trunc_hmac=1 etm=0" \
             0 \
-            -c "16384 bytes written in 1 fragments" \
-            -s "Read from client: 16384 bytes read"
+            -c "16384 bytes written in $(fragments_for_write 16384) fragments" \
+            -s "Read from client: $MAX_CONTENT_LEN bytes read"
 
 run_test    "Large packet TLS 1.2 StreamCipher" \
             "$P_SRV arc4=1 force_ciphersuite=TLS-RSA-WITH-RC4-128-SHA" \
             "$P_CLI request_size=16384 force_version=tls1_2 \
              force_ciphersuite=TLS-RSA-WITH-RC4-128-SHA" \
             0 \
-            -c "16384 bytes written in 1 fragments" \
-            -s "Read from client: 16384 bytes read"
+            -c "16384 bytes written in $(fragments_for_write 16384) fragments" \
+            -s "Read from client: $MAX_CONTENT_LEN bytes read"
 
 run_test    "Large packet TLS 1.2 StreamCipher, without EtM" \
             "$P_SRV arc4=1 force_ciphersuite=TLS-RSA-WITH-RC4-128-SHA" \
             "$P_CLI request_size=16384 force_version=tls1_2 \
              force_ciphersuite=TLS-RSA-WITH-RC4-128-SHA etm=0" \
             0 \
-            -s "Read from client: 16384 bytes read"
+            -s "Read from client: $MAX_CONTENT_LEN bytes read"
 
 requires_config_enabled MBEDTLS_SSL_TRUNCATED_HMAC
 run_test    "Large packet TLS 1.2 StreamCipher, truncated MAC" \
@@ -4176,7 +4206,7 @@
             "$P_CLI request_size=16384 force_version=tls1_2 \
              force_ciphersuite=TLS-RSA-WITH-RC4-128-SHA trunc_hmac=1" \
             0 \
-            -s "Read from client: 16384 bytes read"
+            -s "Read from client: $MAX_CONTENT_LEN bytes read"
 
 requires_config_enabled MBEDTLS_SSL_TRUNCATED_HMAC
 run_test    "Large packet TLS 1.2 StreamCipher, without EtM, truncated MAC" \
@@ -4184,24 +4214,24 @@
             "$P_CLI request_size=16384 force_version=tls1_2 \
              force_ciphersuite=TLS-RSA-WITH-RC4-128-SHA trunc_hmac=1 etm=0" \
             0 \
-            -c "16384 bytes written in 1 fragments" \
-            -s "Read from client: 16384 bytes read"
+            -c "16384 bytes written in $(fragments_for_write 16384) fragments" \
+            -s "Read from client: $MAX_CONTENT_LEN bytes read"
 
 run_test    "Large packet TLS 1.2 AEAD" \
             "$P_SRV" \
             "$P_CLI request_size=16384 force_version=tls1_2 \
              force_ciphersuite=TLS-RSA-WITH-AES-256-CCM" \
             0 \
-            -c "16384 bytes written in 1 fragments" \
-            -s "Read from client: 16384 bytes read"
+            -c "16384 bytes written in $(fragments_for_write 16384) fragments" \
+            -s "Read from client: $MAX_CONTENT_LEN bytes read"
 
 run_test    "Large packet TLS 1.2 AEAD shorter tag" \
             "$P_SRV" \
             "$P_CLI request_size=16384 force_version=tls1_2 \
              force_ciphersuite=TLS-RSA-WITH-AES-256-CCM-8" \
             0 \
-            -c "16384 bytes written in 1 fragments" \
-            -s "Read from client: 16384 bytes read"
+            -c "16384 bytes written in $(fragments_for_write 16384) fragments" \
+            -s "Read from client: $MAX_CONTENT_LEN bytes read"
 
 # Tests of asynchronous private key support in SSL