Add cookie parsing tests to test_suite_ssl

Signed-off-by: Andrzej Kurek <andrzej.kurek@arm.com>

include/mbedtls/ssl_internal.h

@@ -1306,4 +1306,12 @@ void mbedtls_ssl_buffering_free( mbedtls_ssl_context *ssl );
 void mbedtls_ssl_flight_free( mbedtls_ssl_flight_item *flight );
 #endif /* MBEDTLS_SSL_PROTO_DTLS */
 
+#if defined(MBEDTLS_TEST_HOOKS)
+int ssl_check_dtls_clihlo_cookie(
+                          mbedtls_ssl_context *ssl,
+                          const unsigned char *cli_id, size_t cli_id_len,
+                          const unsigned char *in, size_t in_len,
+                          unsigned char *obuf, size_t buf_len, size_t *olen );
+#endif
+
 #endif /* ssl_internal.h */