handshake: add functions to read/write handshake messages directly

This adds a couple of functions, gnutls_handshake_set_read_function()
and gnutls_handshake_write(), to allow QUIC implementations to
directly interact with the TLS state machine.

Signed-off-by: Daiki Ueno <ueno@gnu.org>

1 files changed, 49 insertions, 0 deletions

diff --git a/lib/includes/gnutls/gnutls.h.in b/lib/includes/gnutls/gnutls.h.in
index c45dd542c7..31709117b0 100644
--- a/lib/includes/gnutls/gnutls.h.in
+++ b/lib/includes/gnutls/gnutls.h.in
@@ -3192,6 +3192,55 @@ void gnutls_anti_replay_set_add_function(gnutls_anti_replay_t,
 void gnutls_anti_replay_set_ptr(gnutls_anti_replay_t, void *ptr);
 
 
+/**
+ * gnutls_record_encryption_level_t:
+ * @GNUTLS_ENCRYPTION_LEVEL_INITIAL: initial level that doesn't involve any
+ *    encryption
+ * @GNUTLS_ENCRYPTION_LEVEL_EARLY: early traffic secret is installed
+ * @GNUTLS_ENCRYPTION_LEVEL_HANDSHAKE: handshake traffic secret is installed
+ * @GNUTLS_ENCRYPTION_LEVEL_APPLICATION: application traffic secret is installed
+ *
+ * Enumeration of different levels of record encryption currently in place.
+ * This is used by gnutls_handshake_set_read_function() and
+ * gnutls_handshake_write().
+ *
+ * Since: 3.7.0
+ */
+typedef enum {
+	GNUTLS_ENCRYPTION_LEVEL_INITIAL,
+	GNUTLS_ENCRYPTION_LEVEL_EARLY,
+	GNUTLS_ENCRYPTION_LEVEL_HANDSHAKE,
+	GNUTLS_ENCRYPTION_LEVEL_APPLICATION
+} gnutls_record_encryption_level_t;
+
+  /**
+   * gnutls_handshake_read_func:
+   * @session: the current session
+   * @htype: the type of the handshake message (#gnutls_handshake_description_t)
+   * @level: #gnutls_record_encryption_level_t
+   * @data: the (const) data that was being sent
+   * @data_size: the size of data
+   *
+   * Function prototype for handshake intercepting hooks. It is set using
+   * gnutls_handshake_set_read_function().
+   *
+   * Returns: Non zero on error.
+   * Since: 3.7.0
+   */
+typedef int (*gnutls_handshake_read_func) (gnutls_session_t session,
+					   gnutls_record_encryption_level_t level,
+					   gnutls_handshake_description_t htype,
+					   const void *data, size_t data_size);
+
+void
+gnutls_handshake_set_read_function(gnutls_session_t session,
+				   gnutls_handshake_read_func func);
+
+int
+gnutls_handshake_write(gnutls_session_t session,
+		       gnutls_record_encryption_level_t level,
+		       const void *data, size_t data_size);
+
 /* FIPS140-2 related functions */
 unsigned gnutls_fips140_mode_enabled(void);