1 files changed, 81 insertions, 0 deletions
diff --git a/lib/extv.h b/lib/extv.h
new file mode 100644
index 0000000..3c0bd33
--- /dev/null
+++ b/lib/extv.h
@@ -0,0 +1,81 @@
+/*
+ * Copyright (C) 2017 Red Hat, Inc.
+ *
+ * Author: Nikos Mavrogiannopoulos
+ *
+ * This file is part of GnuTLS.
+ *
+ * The GnuTLS is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>
+ *
+ */
+
+#ifndef GNUTLS_LIB_EXTV_H
+#define GNUTLS_LIB_EXTV_H
+
+#include <gnutls/gnutls.h>
+#include "str.h"
+
+/* Iterates through all TLS-type extensions in data, and
+ * calls the callback function for each of them. The ctx, flags
+ * and parse_type are passed verbatim to callback. */
+int _gnutls_extv_parse(void *ctx,
+		       gnutls_ext_raw_process_func cb,
+		       const uint8_t * data, int data_size);
+
+inline static
+int _gnutls_extv_append_init(gnutls_buffer_st *buf)
+{
+	unsigned pos;
+	int ret;
+
+	pos = buf->length;
+
+	ret = _gnutls_buffer_append_prefix(buf, 16, 0);
+	if (ret < 0)
+		return gnutls_assert_val(ret);
+
+	return pos;
+}
+
+/* its input is the buffer and the return value of _gnutls_extv_append_init()
+ * @is_hello: should be true for client and server hello messages.
+ */
+inline static
+int _gnutls_extv_append_final(gnutls_buffer_st *buf, unsigned init, unsigned is_hello)
+{
+	unsigned size = buf->length - init - 2;
+
+	if (size > UINT16_MAX) /* sent too many extensions */
+		return gnutls_assert_val(GNUTLS_E_HANDSHAKE_TOO_LARGE);
+
+	if (size > 0)
+		_gnutls_write_uint16(size, &buf->data[init]);
+	else if (is_hello && size == 0) {
+		/* there is no point to send empty extension bytes, and
+		 * they are known to break certain clients */
+		buf->length -= 2;
+	}
+
+	return 0;
+}
+
+typedef int (*extv_append_func)(void *ctx, gnutls_buffer_st *buf);
+
+int _gnutls_extv_append(gnutls_buffer_st *buf,
+			uint16_t tls_id,
+		        void *ctx,
+		        extv_append_func cb);
+
+
+#endif /* GNUTLS_LIB_EXTV_H */