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-rw-r--r--stdlib/arc4random.h48
1 files changed, 48 insertions, 0 deletions
diff --git a/stdlib/arc4random.h b/stdlib/arc4random.h
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+++ b/stdlib/arc4random.h
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+/* Arc4random definition used on TLS.
+   Copyright (C) 2022 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library 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.
+
+   The GNU C 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 the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _CHACHA20_H
+#define _CHACHA20_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+/* Internal ChaCha20 state.  */
+#define CHACHA20_STATE_LEN	16
+#define CHACHA20_BLOCK_SIZE	64
+
+/* Maximum number bytes until reseed (16 MB).  */
+#define CHACHA20_RESEED_SIZE	(16 * 1024 * 1024)
+
+/* Internal arc4random buffer, used on each feedback step so offer some
+   backtracking protection and to allow better used of vectorized
+   chacha20 implementations.  */
+#define CHACHA20_BUFSIZE        (8 * CHACHA20_BLOCK_SIZE)
+
+_Static_assert (CHACHA20_BUFSIZE >= CHACHA20_BLOCK_SIZE + CHACHA20_BLOCK_SIZE,
+		"CHACHA20_BUFSIZE < CHACHA20_BLOCK_SIZE + CHACHA20_BLOCK_SIZE");
+
+struct arc4random_state_t
+{
+  uint32_t ctx[CHACHA20_STATE_LEN];
+  size_t have;
+  size_t count;
+  uint8_t buf[CHACHA20_BUFSIZE];
+};
+
+#endif