Add new config MBEDTLS_SSL_SESSION_RESUMPTION

Add a new configuration option MBEDTLS_SSL_SESSION_RESUMPTION
to enable/disable the session resumption feature including
ticket and cache based session resumption.

include/mbedtls/check_config.h

@@ -671,6 +671,12 @@
 #error "MBEDTLS_SSL_SERVER_NAME_INDICATION defined, but not all prerequisites"
 #endif
 
+#if ( defined(MBEDTLS_SSL_SESSION_TICKETS) ||  \
+      defined(MBEDTLS_SSL_SESSION_CACHE) ) &&  \
+      !defined(MBEDTLS_SSL_SESSION_RESUMPTION)
+#error "MBEDTLS_SSL_SESSION_TICKETS/MBEDTLS_SESSION_CACHE cannot be defined without MBEDTLS_SSL_SESSION_RESUMPTION"
+#endif
+
 #if defined(MBEDTLS_THREADING_PTHREAD)
 #if !defined(MBEDTLS_THREADING_C) || defined(MBEDTLS_THREADING_IMPL)
 #error "MBEDTLS_THREADING_PTHREAD defined, but not all prerequisites"

include/mbedtls/config.h

@@ -1676,6 +1676,14 @@
  */
 #define MBEDTLS_SSL_SESSION_CACHE
 
+/**
+ * \def MBEDTLS_SSL_SESSION_RESUMPTION
+ *
+ *
+ * Comment this macro to disable support for SSL session resumption
+ */
+#define MBEDTLS_SSL_SESSION_RESUMPTION
+
 /**
  * \def MBEDTLS_SSL_EXPORT_KEYS
  *

include/mbedtls/ssl_internal.h

@@ -509,7 +509,9 @@ struct mbedtls_ssl_handshake_params
     unsigned char premaster[MBEDTLS_PREMASTER_SIZE];
                                         /*!<  premaster secret        */
 
+#if defined(MBEDTLS_SSL_SESSION_RESUMPTION)
     int resume;                         /*!<  session resume indicator*/
+#endif /* MBEDTLS_SSL_SESSION_RESUMPTION */
     int max_major_ver;                  /*!< max. major version client*/
     int max_minor_ver;                  /*!< max. minor version client*/
     int cli_exts;                       /*!< client extension presence*/