diff --git a/library/ssl_misc.h b/library/ssl_misc.h
index 36754a3..4c3f6c0 100644
--- a/library/ssl_misc.h
+++ b/library/ssl_misc.h
@@ -26,6 +26,7 @@
 
 #include "mbedtls/ssl.h"
 #include "mbedtls/cipher.h"
+#include "mbedtls/debug.h"
 
 #if defined(MBEDTLS_USE_PSA_CRYPTO)
 #include "psa/crypto.h"
@@ -102,6 +103,30 @@
 #define MBEDTLS_SSL_RENEGOTIATION_DONE          2   /* Done or aborted */
 #define MBEDTLS_SSL_RENEGOTIATION_PENDING       3   /* Requested (server only) */
 
+#define MBEDTLS_SSL_PROC_STRIP_PARENS( ... )   __VA_ARGS__
+
+#define MBEDTLS_SSL_PROC_CHK( fn, args )                        \
+    do {                                                        \
+        ret = fn(MBEDTLS_SSL_PROC_STRIP_PARENS args);           \
+        if( ret != 0 )                                          \
+        {                                                       \
+            if( ret > 0 )                                       \
+                ret = MBEDTLS_ERR_SSL_INTERNAL_ERROR;           \
+            MBEDTLS_SSL_DEBUG_RET( 1, #fn, ret );               \
+            goto cleanup;                                       \
+        }                                                       \
+    } while( 0 )
+
+#define MBEDTLS_SSL_PROC_CHK_NEG( fn, args )                    \
+    do {                                                        \
+        ret = fn(MBEDTLS_SSL_PROC_STRIP_PARENS args);           \
+        if( ret < 0 )                                           \
+        {                                                       \
+            MBEDTLS_SSL_DEBUG_RET( 1, #fn, ret );               \
+            goto cleanup;                                       \
+        }                                                       \
+    } while( 0 )
+
 /*
  * DTLS retransmission states, see RFC 6347 4.2.4
  *
@@ -1331,6 +1356,18 @@
     ssl->state = state;
 }
 
+int mbedtls_ssl_start_handshake_msg( mbedtls_ssl_context *ssl,
+                                     unsigned hs_type,
+                                     unsigned char **buf,
+                                     size_t *buflen );
+int mbedtls_ssl_finish_handshake_msg( mbedtls_ssl_context *ssl,
+                                      size_t buf_len,
+                                      size_t msg_len );
+void mbedtls_ssl_add_hs_hdr_to_checksum( mbedtls_ssl_context *ssl,
+                                         unsigned hs_type,
+                                         size_t total_hs_len );
+
+
 #endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */
 
 #endif /* ssl_misc.h */