1/*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2019 Conrad Meyer <cem@FreeBSD.org>
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27#pragma once
28
29#include <dev/random/fenestrasX/fx_rng.h>
30
31#define	FXRNG_BUFRNG_SZ	128
32
33/*
34 * An object representing a buffered random number generator with forward
35 * secrecy (aka "fast-key-erasure").
36 *
37 * There is a single static root instance of this object associated with the
38 * entropy harvester, as well as additional instances per CPU, lazily allocated
39 * in NUMA-local memory, seeded from output of the root generator.
40 */
41struct fxrng_buffered_rng {
42	struct fxrng_basic_rng	brng_rng;
43#define	FXRNG_BRNG_LOCK(brng)	mtx_lock(&(brng)->brng_rng.rng_lk)
44#define	FXRNG_BRNG_UNLOCK(brng)	mtx_unlock(&(brng)->brng_rng.rng_lk)
45#define	FXRNG_BRNG_ASSERT(brng)	mtx_assert(&(brng)->brng_rng.rng_lk, MA_OWNED)
46#define	FXRNG_BRNG_ASSERT_NOT(brng) \
47	mtx_assert(&(brng)->brng_rng.rng_lk, MA_NOTOWNED)
48
49	/* Entropy reseed generation ("seed version"). */
50	uint64_t	brng_generation;
51
52	/* Buffered output for quick access by small requests. */
53	uint8_t		brng_buffer[FXRNG_BUFRNG_SZ];
54	uint8_t		brng_avail_idx;
55};
56
57void fxrng_brng_init(struct fxrng_buffered_rng *);
58void fxrng_brng_produce_seed_data_internal(struct fxrng_buffered_rng *, void *,
59    size_t, uint64_t *seed_generation);
60void fxrng_brng_read(struct fxrng_buffered_rng *, void *, size_t);
61
62void fxrng_brng_reseed(const void *, size_t);
63struct harvest_event;
64void fxrng_brng_src_reseed(const struct harvest_event *);
65