xref: /freebsd/sys/dev/random/random_harvestq.h (revision e2a96b83404fcee0a079a3c3adbb448b86a38d1e)
1 /*-
2  * Copyright (c) 2013-2015, 2017 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 #ifndef SYS_DEV_RANDOM_RANDOM_HARVESTQ_H_INCLUDED
28 #define	SYS_DEV_RANDOM_RANDOM_HARVESTQ_H_INCLUDED
29 
30 #include <sys/types.h>
31 #include <machine/cpu.h>
32 
33 #define	HARVESTSIZE	2	/* Max length in words of each harvested entropy unit */
34 
35 /* These are used to queue harvested packets of entropy. The entropy
36  * buffer size is pretty arbitrary.
37  */
38 struct harvest_event {
39 	uint32_t	he_somecounter;		/* fast counter for clock jitter */
40 	uint32_t	he_entropy[HARVESTSIZE];/* some harvested entropy */
41 	uint8_t		he_size;		/* harvested entropy byte count */
42 	uint8_t		he_destination;		/* destination pool of this entropy */
43 	uint8_t		he_source;		/* origin of the entropy */
44 };
45 
46 static inline uint32_t
random_get_cyclecount(void)47 random_get_cyclecount(void)
48 {
49 	return ((uint32_t)get_cyclecount());
50 }
51 
52 #endif /* SYS_DEV_RANDOM_RANDOM_HARVESTQ_H_INCLUDED */
53