freebsd-skq/sys/dev/random/yarrow.h
Mark Murray 84d4f509f0 Major speedup to /dev/random and the kernel thread that reseeds it.
There is no more TAILQ fifo to harvest the entropy; instead, there
is a circular buffer of constant size (changeable by macro) that
pretty dramatically improves the speed and fixes potential slowdowns-
by-locking.

Also gone are a slew of malloc(9) and free(9) calls; all harvesting
buffers are static.

All-in-all, this is a good performance improvement.

Thanks-to:	msmith for the circular buffer concept-code.
2000-12-02 18:40:16 +00:00

78 lines
2.9 KiB
C

/*-
* Copyright (c) 2000 Mark R V Murray
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer
* in this position and unchanged.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* $FreeBSD$
*/
/* #define ENTROPYSOURCE nn entropy sources (actually classes)
* This is properly defined in
* an enum in sys/random.h
*/
#define HARVEST_RING_SIZE 1024 /* harvest ring buffer size */
#define TIMEBIN 16 /* max value for Pt/t */
#define HARVESTSIZE 16 /* max size of each harvested entropy unit */
#define FAST 0
#define SLOW 1
int random_init(void);
void random_deinit(void);
void random_init_harvester(void (*)(u_int64_t, void *, u_int, u_int, u_int, enum esource), u_int (*)(void *, u_int));
void random_deinit_harvester(void);
void random_set_wakeup_exit(void *);
void random_reseed(void);
u_int read_random_real(void *, u_int);
void write_random(void *, u_int);
/* This is the beastie that needs protecting. It contains all of the
* state that we are excited about.
*/
struct random_state {
u_int64_t counter; /* C */
struct yarrowkey key; /* K */
int gengateinterval; /* Pg */
int bins; /* Pt/t */
int outputblocks; /* count output blocks for gates */
u_int slowoverthresh; /* slow pool overthreshhold reseed count */
struct pool {
struct source {
u_int bits; /* estimated bits of entropy */
u_int frac; /* fractional bits of entropy
(given as 1024/n) */
} source[ENTROPYSOURCE];
u_int thresh; /* pool reseed threshhold */
struct yarrowhash hash; /* accumulated entropy */
} pool[2]; /* pool[0] is fast, pool[1] is slow */
int which; /* toggle - shows the current insertion pool */
int seeded; /* 0 until first reseed, then 1 */
struct selinfo rsel; /* For poll(2) */
};
extern struct random_state random_state;