1/*-
2 * Copyright (c) 2015 Mark R V Murray
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer
10 *    in this position and unchanged.
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 ``AS IS'' AND ANY EXPRESS OR
16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 *
26 */
27
28#include <sys/cdefs.h>
29__FBSDID("$FreeBSD$");
30
31#include <sys/param.h>
32#include <sys/systm.h>
33#include <sys/kernel.h>
34#include <sys/malloc.h>
35#include <sys/random.h>
36#include <sys/sysctl.h>
37
38#if defined(RANDOM_LOADABLE)
39#include <sys/lock.h>
40#include <sys/sx.h>
41#endif
42
43#include <dev/random/randomdev.h>
44
45/* Set up the sysctl root node for the entropy device */
46SYSCTL_NODE(_kern, OID_AUTO, random, CTLFLAG_RW, 0, "Cryptographically Secure Random Number Generator");
47
48MALLOC_DEFINE(M_ENTROPY, "entropy", "Entropy harvesting buffers and data structures");
49
50struct sources_head source_list = LIST_HEAD_INITIALIZER(source_list);
51
52#if defined(RANDOM_LOADABLE)
53struct random_algorithm *p_random_alg_context = NULL;
54#else /* !defined(RANDOM_LOADABLE) */
55struct random_algorithm *p_random_alg_context = &random_alg_context;
56#endif /* defined(RANDOM_LOADABLE) */
57
58#if defined(RANDOM_LOADABLE)
59
60struct random_readers {
61	int	(*read_random_uio)(struct uio *, bool);
62	u_int	(*read_random)(void *, u_int);
63} random_reader_context = {
64	(int (*)(struct uio *, bool))nullop,
65	(u_int (*)(void *, u_int))nullop,
66};
67
68struct sx randomdev_config_lock;
69
70static void
71random_infra_sysinit(void *dummy __unused)
72{
73
74	RANDOM_CONFIG_INIT_LOCK();
75}
76SYSINIT(random_device_h_init, SI_SUB_RANDOM, SI_ORDER_FIRST, random_infra_sysinit, NULL);
77
78void
79random_infra_init(int (*p_random_read_uio)(struct uio *, bool), u_int (*p_random_read)(void *, u_int))
80{
81
82	RANDOM_CONFIG_X_LOCK();
83	random_reader_context.read_random_uio = p_random_read_uio;
84	random_reader_context.read_random = p_random_read;
85	RANDOM_CONFIG_X_UNLOCK();
86}
87
88void
89random_infra_uninit(void)
90{
91
92	RANDOM_CONFIG_X_LOCK();
93	random_reader_context.read_random_uio = (int (*)(struct uio *, bool))nullop;
94	random_reader_context.read_random = (u_int (*)(void *, u_int))nullop;
95	RANDOM_CONFIG_X_UNLOCK();
96}
97
98static void
99random_infra_sysuninit(void *dummy __unused)
100{
101
102	RANDOM_CONFIG_DEINIT_LOCK();
103}
104SYSUNINIT(random_device_h_init, SI_SUB_RANDOM, SI_ORDER_FIRST, random_infra_sysuninit, NULL);
105
106int
107read_random_uio(struct uio *uio, bool nonblock)
108{
109	int retval;
110
111	RANDOM_CONFIG_S_LOCK();
112	retval = random_reader_context.read_random_uio(uio, nonblock);
113	RANDOM_CONFIG_S_UNLOCK();
114	return (retval);
115}
116
117u_int
118read_random(void *buf, u_int len)
119{
120	u_int retval;
121
122	RANDOM_CONFIG_S_LOCK();
123	retval = random_reader_context.read_random(buf, len);
124	RANDOM_CONFIG_S_UNLOCK();
125	return (retval);
126}
127
128#endif /* defined(RANDOM_LOADABLE) */
129