1085 lines
23 KiB
C
1085 lines
23 KiB
C
/* $NetBSD: rnd.c,v 1.63 2007/07/09 21:00:29 ad Exp $ */
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/*-
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* Copyright (c) 1997 The NetBSD Foundation, Inc.
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* All rights reserved.
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*
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* This code is derived from software contributed to The NetBSD Foundation
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* by Michael Graff <explorer@flame.org>. This code uses ideas and
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* algorithms from the Linux driver written by Ted Ts'o.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by the NetBSD
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* Foundation, Inc. and its contributors.
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* 4. Neither the name of The NetBSD Foundation nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__KERNEL_RCSID(0, "$NetBSD: rnd.c,v 1.63 2007/07/09 21:00:29 ad Exp $");
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#include <sys/param.h>
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#include <sys/ioctl.h>
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#include <sys/fcntl.h>
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#include <sys/select.h>
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#include <sys/poll.h>
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#include <sys/malloc.h>
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#include <sys/proc.h>
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#include <sys/kernel.h>
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#include <sys/conf.h>
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#include <sys/systm.h>
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#include <sys/callout.h>
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#include <sys/rnd.h>
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#include <sys/vnode.h>
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#include <sys/pool.h>
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#include <sys/kauth.h>
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#ifdef __HAVE_CPU_COUNTER
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#include <machine/cpu_counter.h>
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#endif
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#ifdef RND_DEBUG
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#define DPRINTF(l,x) if (rnd_debug & (l)) printf x
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int rnd_debug = 0;
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#else
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#define DPRINTF(l,x)
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#endif
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#define RND_DEBUG_WRITE 0x0001
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#define RND_DEBUG_READ 0x0002
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#define RND_DEBUG_IOCTL 0x0004
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#define RND_DEBUG_SNOOZE 0x0008
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/*
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* list devices attached
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*/
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#if 0
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#define RND_VERBOSE
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#endif
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/*
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* Use the extraction time as a somewhat-random source
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*/
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#ifndef RND_USE_EXTRACT_TIME
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#define RND_USE_EXTRACT_TIME 1
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#endif
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/*
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* The size of a temporary buffer, malloc()ed when needed, and used for
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* reading and writing data.
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*/
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#define RND_TEMP_BUFFER_SIZE 128
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/*
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* This is a little bit of state information attached to each device that we
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* collect entropy from. This is simply a collection buffer, and when it
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* is full it will be "detached" from the source and added to the entropy
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* pool after entropy is distilled as much as possible.
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*/
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#define RND_SAMPLE_COUNT 64 /* collect N samples, then compress */
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typedef struct _rnd_sample_t {
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SIMPLEQ_ENTRY(_rnd_sample_t) next;
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rndsource_t *source;
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int cursor;
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int entropy;
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u_int32_t ts[RND_SAMPLE_COUNT];
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u_int32_t values[RND_SAMPLE_COUNT];
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} rnd_sample_t;
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/*
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* The event queue. Fields are altered at an interrupt level.
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* All accesses must be protected at splvm().
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*/
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volatile int rnd_timeout_pending;
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SIMPLEQ_HEAD(, _rnd_sample_t) rnd_samples;
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/*
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* our select/poll queue
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*/
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struct selinfo rnd_selq;
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/*
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* Set when there are readers blocking on data from us
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*/
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#define RND_READWAITING 0x00000001
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volatile u_int32_t rnd_status;
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/*
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* Memory pool; accessed only at splvm().
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*/
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POOL_INIT(rnd_mempool, sizeof(rnd_sample_t), 0, 0, 0, "rndsample", NULL,
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IPL_VM);
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/*
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* Our random pool. This is defined here rather than using the general
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* purpose one defined in rndpool.c.
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*
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* Samples are collected and queued at splvm() into a separate queue
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* (rnd_samples, see above), and processed in a timeout routine; therefore,
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* all other accesses to the random pool must be at splsoftclock() as well.
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*/
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rndpool_t rnd_pool;
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/*
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* This source is used to easily "remove" queue entries when the source
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* which actually generated the events is going away.
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*/
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static rndsource_t rnd_source_no_collect = {
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{ 'N', 'o', 'C', 'o', 'l', 'l', 'e', 'c', 't', 0, 0, 0, 0, 0, 0, 0 },
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0, 0, 0, 0,
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RND_TYPE_UNKNOWN,
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(RND_FLAG_NO_COLLECT | RND_FLAG_NO_ESTIMATE | RND_TYPE_UNKNOWN),
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NULL
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};
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struct callout rnd_callout;
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void rndattach(int);
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dev_type_open(rndopen);
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dev_type_read(rndread);
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dev_type_write(rndwrite);
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dev_type_ioctl(rndioctl);
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dev_type_poll(rndpoll);
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dev_type_kqfilter(rndkqfilter);
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const struct cdevsw rnd_cdevsw = {
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rndopen, nullclose, rndread, rndwrite, rndioctl,
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nostop, notty, rndpoll, nommap, rndkqfilter, D_OTHER,
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};
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static inline void rnd_wakeup_readers(void);
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static inline u_int32_t rnd_estimate_entropy(rndsource_t *, u_int32_t);
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static inline u_int32_t rnd_counter(void);
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static void rnd_timeout(void *);
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static int rnd_ready = 0;
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static int rnd_have_entropy = 0;
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LIST_HEAD(, __rndsource_element) rnd_sources;
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/*
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* Generate a 32-bit counter. This should be more machine dependant,
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* using cycle counters and the like when possible.
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*/
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static inline u_int32_t
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rnd_counter(void)
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{
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struct timeval tv;
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#ifdef __HAVE_CPU_COUNTER
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if (cpu_hascounter())
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return (cpu_counter32());
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#endif
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if (rnd_ready) {
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microtime(&tv);
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return (tv.tv_sec * 1000000 + tv.tv_usec);
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}
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/* when called from rnd_init, its too early to call microtime safely */
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return (0);
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}
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/*
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* Check to see if there are readers waiting on us. If so, kick them.
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*
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* Must be called at splsoftclock().
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*/
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static inline void
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rnd_wakeup_readers(void)
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{
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/*
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* If we have added new bits, and now have enough to do something,
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* wake up sleeping readers.
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*/
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if (rndpool_get_entropy_count(&rnd_pool) > RND_ENTROPY_THRESHOLD * 8) {
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if (rnd_status & RND_READWAITING) {
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DPRINTF(RND_DEBUG_SNOOZE,
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("waking up pending readers.\n"));
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rnd_status &= ~RND_READWAITING;
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wakeup(&rnd_selq);
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}
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selnotify(&rnd_selq, 0);
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#ifdef RND_VERBOSE
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if (!rnd_have_entropy)
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printf("rnd: have initial entropy (%u)\n",
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rndpool_get_entropy_count(&rnd_pool));
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#endif
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rnd_have_entropy = 1;
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}
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}
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/*
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* Use the timing of the event to estimate the entropy gathered.
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* If all the differentials (first, second, and third) are non-zero, return
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* non-zero. If any of these are zero, return zero.
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*/
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static inline u_int32_t
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rnd_estimate_entropy(rndsource_t *rs, u_int32_t t)
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{
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int32_t delta, delta2, delta3;
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/*
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* If the time counter has overflowed, calculate the real difference.
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* If it has not, it is simplier.
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*/
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if (t < rs->last_time)
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delta = UINT_MAX - rs->last_time + t;
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else
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delta = rs->last_time - t;
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if (delta < 0)
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delta = -delta;
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/*
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* Calculate the second and third order differentials
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*/
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delta2 = rs->last_delta - delta;
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if (delta2 < 0)
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delta2 = -delta2;
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delta3 = rs->last_delta2 - delta2;
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if (delta3 < 0)
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delta3 = -delta3;
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rs->last_time = t;
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rs->last_delta = delta;
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rs->last_delta2 = delta2;
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/*
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* If any delta is 0, we got no entropy. If all are non-zero, we
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* might have something.
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*/
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if (delta == 0 || delta2 == 0 || delta3 == 0)
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return (0);
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return (1);
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}
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/*
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* "Attach" the random device. This is an (almost) empty stub, since
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* pseudo-devices don't get attached until after config, after the
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* entropy sources will attach. We just use the timing of this event
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* as another potential source of initial entropy.
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*/
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void
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rndattach(int num)
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{
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u_int32_t c;
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/* Trap unwary players who don't call rnd_init() early */
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KASSERT(rnd_ready);
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/* mix in another counter */
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c = rnd_counter();
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rndpool_add_data(&rnd_pool, &c, sizeof(u_int32_t), 1);
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}
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/*
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* initialize the global random pool for our use.
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* rnd_init() must be called very early on in the boot process, so
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* the pool is ready for other devices to attach as sources.
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*/
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void
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rnd_init(void)
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{
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u_int32_t c;
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if (rnd_ready)
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return;
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callout_init(&rnd_callout, 0);
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/*
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* take a counter early, hoping that there's some variance in
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* the following operations
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*/
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c = rnd_counter();
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LIST_INIT(&rnd_sources);
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SIMPLEQ_INIT(&rnd_samples);
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rndpool_init(&rnd_pool);
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/* Mix *something*, *anything* into the pool to help it get started.
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* However, it's not safe for rnd_counter() to call microtime() yet,
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* so on some platforms we might just end up with zeros anyway.
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* XXX more things to add would be nice.
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*/
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if (c) {
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rndpool_add_data(&rnd_pool, &c, sizeof(u_int32_t), 1);
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c = rnd_counter();
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rndpool_add_data(&rnd_pool, &c, sizeof(u_int32_t), 1);
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}
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rnd_ready = 1;
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#ifdef RND_VERBOSE
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printf("rnd: initialised (%u)%s", RND_POOLBITS,
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c ? " with counter\n" : "\n");
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#endif
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}
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int
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rndopen(dev_t dev, int flags, int ifmt,
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struct lwp *l)
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{
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if (rnd_ready == 0)
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return (ENXIO);
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if (minor(dev) == RND_DEV_URANDOM || minor(dev) == RND_DEV_RANDOM)
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return (0);
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return (ENXIO);
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}
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int
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rndread(dev_t dev, struct uio *uio, int ioflag)
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{
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u_int8_t *bf;
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u_int32_t entcnt, mode, n, nread;
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int ret, s;
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DPRINTF(RND_DEBUG_READ,
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("Random: Read of %d requested, flags 0x%08x\n",
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uio->uio_resid, ioflag));
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if (uio->uio_resid == 0)
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return (0);
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switch (minor(dev)) {
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case RND_DEV_RANDOM:
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mode = RND_EXTRACT_GOOD;
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break;
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case RND_DEV_URANDOM:
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mode = RND_EXTRACT_ANY;
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break;
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default:
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/* Can't happen, but this is cheap */
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return (ENXIO);
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}
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ret = 0;
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bf = malloc(RND_TEMP_BUFFER_SIZE, M_TEMP, M_WAITOK);
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while (uio->uio_resid > 0) {
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n = min(RND_TEMP_BUFFER_SIZE, uio->uio_resid);
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/*
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* Make certain there is data available. If there
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* is, do the I/O even if it is partial. If not,
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* sleep unless the user has requested non-blocking
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* I/O.
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*/
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for (;;) {
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/*
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* If not requesting strong randomness, we
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* can always read.
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*/
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if (mode == RND_EXTRACT_ANY)
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break;
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/*
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* How much entropy do we have? If it is enough for
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* one hash, we can read.
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*/
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s = splsoftclock();
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entcnt = rndpool_get_entropy_count(&rnd_pool);
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splx(s);
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if (entcnt >= RND_ENTROPY_THRESHOLD * 8)
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break;
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/*
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* Data is not available.
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*/
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if (ioflag & IO_NDELAY) {
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ret = EWOULDBLOCK;
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goto out;
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}
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rnd_status |= RND_READWAITING;
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ret = tsleep(&rnd_selq, PRIBIO|PCATCH,
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"rndread", 0);
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if (ret)
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goto out;
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}
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nread = rnd_extract_data(bf, n, mode);
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/*
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* Copy (possibly partial) data to the user.
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* If an error occurs, or this is a partial
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* read, bail out.
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*/
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ret = uiomove((void *)bf, nread, uio);
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if (ret != 0 || nread != n)
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goto out;
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}
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out:
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free(bf, M_TEMP);
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return (ret);
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}
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int
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rndwrite(dev_t dev, struct uio *uio, int ioflag)
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{
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u_int8_t *bf;
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int n, ret, s;
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DPRINTF(RND_DEBUG_WRITE,
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("Random: Write of %d requested\n", uio->uio_resid));
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if (uio->uio_resid == 0)
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return (0);
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ret = 0;
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bf = malloc(RND_TEMP_BUFFER_SIZE, M_TEMP, M_WAITOK);
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while (uio->uio_resid > 0) {
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n = min(RND_TEMP_BUFFER_SIZE, uio->uio_resid);
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ret = uiomove((void *)bf, n, uio);
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if (ret != 0)
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break;
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/*
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* Mix in the bytes.
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*/
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s = splsoftclock();
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rndpool_add_data(&rnd_pool, bf, n, 0);
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splx(s);
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DPRINTF(RND_DEBUG_WRITE, ("Random: Copied in %d bytes\n", n));
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}
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free(bf, M_TEMP);
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return (ret);
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}
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|
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int
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rndioctl(dev_t dev, u_long cmd, void *addr, int flag,
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struct lwp *l)
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{
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rndsource_element_t *rse;
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rndstat_t *rst;
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rndstat_name_t *rstnm;
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rndctl_t *rctl;
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rnddata_t *rnddata;
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u_int32_t count, start;
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int ret, s;
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ret = 0;
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switch (cmd) {
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case FIONBIO:
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case FIOASYNC:
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case RNDGETENTCNT:
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break;
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case RNDGETPOOLSTAT:
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case RNDGETSRCNUM:
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case RNDGETSRCNAME:
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case RNDCTL:
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case RNDADDDATA:
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ret = kauth_authorize_generic(l->l_cred, KAUTH_GENERIC_ISSUSER,
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NULL);
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if (ret)
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return (ret);
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break;
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default:
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return (EINVAL);
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}
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|
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switch (cmd) {
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|
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/*
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* Handled in upper layer really, but we have to return zero
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* for it to be accepted by the upper layer.
|
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*/
|
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case FIONBIO:
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case FIOASYNC:
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break;
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|
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case RNDGETENTCNT:
|
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s = splsoftclock();
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*(u_int32_t *)addr = rndpool_get_entropy_count(&rnd_pool);
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splx(s);
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break;
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|
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case RNDGETPOOLSTAT:
|
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s = splsoftclock();
|
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rndpool_get_stats(&rnd_pool, addr, sizeof(rndpoolstat_t));
|
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splx(s);
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break;
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|
|
case RNDGETSRCNUM:
|
|
rst = (rndstat_t *)addr;
|
|
|
|
if (rst->count == 0)
|
|
break;
|
|
|
|
if (rst->count > RND_MAXSTATCOUNT)
|
|
return (EINVAL);
|
|
|
|
/*
|
|
* Find the starting source by running through the
|
|
* list of sources.
|
|
*/
|
|
rse = rnd_sources.lh_first;
|
|
start = rst->start;
|
|
while (rse != NULL && start >= 1) {
|
|
rse = rse->list.le_next;
|
|
start--;
|
|
}
|
|
|
|
/*
|
|
* Return up to as many structures as the user asked
|
|
* for. If we run out of sources, a count of zero
|
|
* will be returned, without an error.
|
|
*/
|
|
for (count = 0; count < rst->count && rse != NULL; count++) {
|
|
memcpy(&rst->source[count], &rse->data,
|
|
sizeof(rndsource_t));
|
|
/* Zero out information which may leak */
|
|
rst->source[count].last_time = 0;
|
|
rst->source[count].last_delta = 0;
|
|
rst->source[count].last_delta2 = 0;
|
|
rst->source[count].state = 0;
|
|
rse = rse->list.le_next;
|
|
}
|
|
|
|
rst->count = count;
|
|
|
|
break;
|
|
|
|
case RNDGETSRCNAME:
|
|
/*
|
|
* Scan through the list, trying to find the name.
|
|
*/
|
|
rstnm = (rndstat_name_t *)addr;
|
|
rse = rnd_sources.lh_first;
|
|
while (rse != NULL) {
|
|
if (strncmp(rse->data.name, rstnm->name, 16) == 0) {
|
|
memcpy(&rstnm->source, &rse->data,
|
|
sizeof(rndsource_t));
|
|
|
|
return (0);
|
|
}
|
|
rse = rse->list.le_next;
|
|
}
|
|
|
|
ret = ENOENT; /* name not found */
|
|
|
|
break;
|
|
|
|
case RNDCTL:
|
|
/*
|
|
* Set flags to enable/disable entropy counting and/or
|
|
* collection.
|
|
*/
|
|
rctl = (rndctl_t *)addr;
|
|
rse = rnd_sources.lh_first;
|
|
|
|
/*
|
|
* Flags set apply to all sources of this type.
|
|
*/
|
|
if (rctl->type != 0xff) {
|
|
while (rse != NULL) {
|
|
if (rse->data.type == rctl->type) {
|
|
rse->data.flags &= ~rctl->mask;
|
|
rse->data.flags |=
|
|
(rctl->flags & rctl->mask);
|
|
}
|
|
rse = rse->list.le_next;
|
|
}
|
|
|
|
return (0);
|
|
}
|
|
|
|
/*
|
|
* scan through the list, trying to find the name
|
|
*/
|
|
while (rse != NULL) {
|
|
if (strncmp(rse->data.name, rctl->name, 16) == 0) {
|
|
rse->data.flags &= ~rctl->mask;
|
|
rse->data.flags |= (rctl->flags & rctl->mask);
|
|
|
|
return (0);
|
|
}
|
|
rse = rse->list.le_next;
|
|
}
|
|
|
|
ret = ENOENT; /* name not found */
|
|
|
|
break;
|
|
|
|
case RNDADDDATA:
|
|
rnddata = (rnddata_t *)addr;
|
|
|
|
s = splsoftclock();
|
|
rndpool_add_data(&rnd_pool, rnddata->data, rnddata->len,
|
|
rnddata->entropy);
|
|
|
|
rnd_wakeup_readers();
|
|
splx(s);
|
|
|
|
break;
|
|
|
|
default:
|
|
return (EINVAL);
|
|
}
|
|
|
|
return (ret);
|
|
}
|
|
|
|
int
|
|
rndpoll(dev_t dev, int events, struct lwp *l)
|
|
{
|
|
u_int32_t entcnt;
|
|
int revents, s;
|
|
|
|
/*
|
|
* We are always writable.
|
|
*/
|
|
revents = events & (POLLOUT | POLLWRNORM);
|
|
|
|
/*
|
|
* Save some work if not checking for reads.
|
|
*/
|
|
if ((events & (POLLIN | POLLRDNORM)) == 0)
|
|
return (revents);
|
|
|
|
/*
|
|
* If the minor device is not /dev/random, we are always readable.
|
|
*/
|
|
if (minor(dev) != RND_DEV_RANDOM) {
|
|
revents |= events & (POLLIN | POLLRDNORM);
|
|
return (revents);
|
|
}
|
|
|
|
/*
|
|
* Make certain we have enough entropy to be readable.
|
|
*/
|
|
s = splsoftclock();
|
|
entcnt = rndpool_get_entropy_count(&rnd_pool);
|
|
splx(s);
|
|
|
|
if (entcnt >= RND_ENTROPY_THRESHOLD * 8)
|
|
revents |= events & (POLLIN | POLLRDNORM);
|
|
else
|
|
selrecord(l, &rnd_selq);
|
|
|
|
return (revents);
|
|
}
|
|
|
|
static void
|
|
filt_rnddetach(struct knote *kn)
|
|
{
|
|
int s;
|
|
|
|
s = splsoftclock();
|
|
SLIST_REMOVE(&rnd_selq.sel_klist, kn, knote, kn_selnext);
|
|
splx(s);
|
|
}
|
|
|
|
static int
|
|
filt_rndread(struct knote *kn, long hint)
|
|
{
|
|
uint32_t entcnt;
|
|
|
|
entcnt = rndpool_get_entropy_count(&rnd_pool);
|
|
if (entcnt >= RND_ENTROPY_THRESHOLD * 8) {
|
|
kn->kn_data = RND_TEMP_BUFFER_SIZE;
|
|
return (1);
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
static const struct filterops rnd_seltrue_filtops =
|
|
{ 1, NULL, filt_rnddetach, filt_seltrue };
|
|
|
|
static const struct filterops rndread_filtops =
|
|
{ 1, NULL, filt_rnddetach, filt_rndread };
|
|
|
|
int
|
|
rndkqfilter(dev_t dev, struct knote *kn)
|
|
{
|
|
struct klist *klist;
|
|
int s;
|
|
|
|
switch (kn->kn_filter) {
|
|
case EVFILT_READ:
|
|
klist = &rnd_selq.sel_klist;
|
|
if (minor(dev) == RND_DEV_URANDOM)
|
|
kn->kn_fop = &rnd_seltrue_filtops;
|
|
else
|
|
kn->kn_fop = &rndread_filtops;
|
|
break;
|
|
|
|
case EVFILT_WRITE:
|
|
klist = &rnd_selq.sel_klist;
|
|
kn->kn_fop = &rnd_seltrue_filtops;
|
|
break;
|
|
|
|
default:
|
|
return (1);
|
|
}
|
|
|
|
kn->kn_hook = NULL;
|
|
|
|
s = splsoftclock();
|
|
SLIST_INSERT_HEAD(klist, kn, kn_selnext);
|
|
splx(s);
|
|
|
|
return (0);
|
|
}
|
|
|
|
static rnd_sample_t *
|
|
rnd_sample_allocate(rndsource_t *source)
|
|
{
|
|
rnd_sample_t *c;
|
|
int s;
|
|
|
|
s = splvm();
|
|
c = pool_get(&rnd_mempool, PR_WAITOK);
|
|
splx(s);
|
|
if (c == NULL)
|
|
return (NULL);
|
|
|
|
c->source = source;
|
|
c->cursor = 0;
|
|
c->entropy = 0;
|
|
|
|
return (c);
|
|
}
|
|
|
|
/*
|
|
* Don't wait on allocation. To be used in an interrupt context.
|
|
*/
|
|
static rnd_sample_t *
|
|
rnd_sample_allocate_isr(rndsource_t *source)
|
|
{
|
|
rnd_sample_t *c;
|
|
int s;
|
|
|
|
s = splvm();
|
|
c = pool_get(&rnd_mempool, 0);
|
|
splx(s);
|
|
if (c == NULL)
|
|
return (NULL);
|
|
|
|
c->source = source;
|
|
c->cursor = 0;
|
|
c->entropy = 0;
|
|
|
|
return (c);
|
|
}
|
|
|
|
static void
|
|
rnd_sample_free(rnd_sample_t *c)
|
|
{
|
|
int s;
|
|
|
|
memset(c, 0, sizeof(rnd_sample_t));
|
|
s = splvm();
|
|
pool_put(&rnd_mempool, c);
|
|
splx(s);
|
|
}
|
|
|
|
/*
|
|
* Add a source to our list of sources.
|
|
*/
|
|
void
|
|
rnd_attach_source(rndsource_element_t *rs, const char *name, u_int32_t type,
|
|
u_int32_t flags)
|
|
{
|
|
u_int32_t ts;
|
|
|
|
ts = rnd_counter();
|
|
|
|
strlcpy(rs->data.name, name, sizeof(rs->data.name));
|
|
rs->data.last_time = ts;
|
|
rs->data.last_delta = 0;
|
|
rs->data.last_delta2 = 0;
|
|
rs->data.total = 0;
|
|
|
|
/*
|
|
* Force network devices to not collect any entropy by
|
|
* default.
|
|
*/
|
|
if (type == RND_TYPE_NET)
|
|
flags |= (RND_FLAG_NO_COLLECT | RND_FLAG_NO_ESTIMATE);
|
|
|
|
rs->data.type = type;
|
|
rs->data.flags = flags;
|
|
|
|
rs->data.state = rnd_sample_allocate(&rs->data);
|
|
|
|
LIST_INSERT_HEAD(&rnd_sources, rs, list);
|
|
|
|
#ifdef RND_VERBOSE
|
|
printf("rnd: %s attached as an entropy source (", rs->data.name);
|
|
if (!(flags & RND_FLAG_NO_COLLECT)) {
|
|
printf("collecting");
|
|
if (flags & RND_FLAG_NO_ESTIMATE)
|
|
printf(" without estimation");
|
|
}
|
|
else
|
|
printf("off");
|
|
printf(")\n");
|
|
#endif
|
|
|
|
/*
|
|
* Again, put some more initial junk in the pool.
|
|
* XXX Bogus, but harder to guess than zeros.
|
|
*/
|
|
rndpool_add_data(&rnd_pool, &ts, sizeof(u_int32_t), 1);
|
|
}
|
|
|
|
/*
|
|
* Remove a source from our list of sources.
|
|
*/
|
|
void
|
|
rnd_detach_source(rndsource_element_t *rs)
|
|
{
|
|
rnd_sample_t *sample;
|
|
rndsource_t *source;
|
|
int s;
|
|
|
|
s = splvm();
|
|
|
|
LIST_REMOVE(rs, list);
|
|
|
|
source = &rs->data;
|
|
|
|
if (source->state) {
|
|
rnd_sample_free(source->state);
|
|
source->state = NULL;
|
|
}
|
|
|
|
/*
|
|
* If there are samples queued up "remove" them from the sample queue
|
|
* by setting the source to the no-collect pseudosource.
|
|
*/
|
|
sample = SIMPLEQ_FIRST(&rnd_samples);
|
|
while (sample != NULL) {
|
|
if (sample->source == source)
|
|
sample->source = &rnd_source_no_collect;
|
|
|
|
sample = SIMPLEQ_NEXT(sample, next);
|
|
}
|
|
|
|
splx(s);
|
|
#ifdef RND_VERBOSE
|
|
printf("rnd: %s detached as an entropy source\n", rs->data.name);
|
|
#endif
|
|
}
|
|
|
|
/*
|
|
* Add a value to the entropy pool. The rs parameter should point to the
|
|
* source-specific source structure.
|
|
*/
|
|
void
|
|
rnd_add_uint32(rndsource_element_t *rs, u_int32_t val)
|
|
{
|
|
rndsource_t *rst;
|
|
rnd_sample_t *state;
|
|
u_int32_t ts;
|
|
int s;
|
|
|
|
rst = &rs->data;
|
|
|
|
if (rst->flags & RND_FLAG_NO_COLLECT)
|
|
return;
|
|
|
|
/*
|
|
* Sample the counter as soon as possible to avoid
|
|
* entropy overestimation.
|
|
*/
|
|
ts = rnd_counter();
|
|
|
|
/*
|
|
* If the sample buffer is NULL, try to allocate one here. If this
|
|
* fails, drop this sample.
|
|
*/
|
|
state = rst->state;
|
|
if (state == NULL) {
|
|
state = rnd_sample_allocate_isr(rst);
|
|
if (state == NULL)
|
|
return;
|
|
rst->state = state;
|
|
}
|
|
|
|
/*
|
|
* If we are estimating entropy on this source,
|
|
* calculate differentials.
|
|
*/
|
|
|
|
if ((rst->flags & RND_FLAG_NO_ESTIMATE) == 0)
|
|
state->entropy += rnd_estimate_entropy(rst, ts);
|
|
|
|
state->ts[state->cursor] = ts;
|
|
state->values[state->cursor] = val;
|
|
state->cursor++;
|
|
|
|
/*
|
|
* If the state arrays are not full, we're done.
|
|
*/
|
|
if (state->cursor < RND_SAMPLE_COUNT)
|
|
return;
|
|
|
|
/*
|
|
* State arrays are full. Queue this chunk on the processing queue.
|
|
*/
|
|
s = splvm();
|
|
SIMPLEQ_INSERT_HEAD(&rnd_samples, state, next);
|
|
rst->state = NULL;
|
|
|
|
/*
|
|
* If the timeout isn't pending, have it run in the near future.
|
|
*/
|
|
if (rnd_timeout_pending == 0) {
|
|
rnd_timeout_pending = 1;
|
|
callout_reset(&rnd_callout, 1, rnd_timeout, NULL);
|
|
}
|
|
splx(s);
|
|
|
|
/*
|
|
* To get here we have to have queued the state up, and therefore
|
|
* we need a new state buffer. If we can, allocate one now;
|
|
* if we don't get it, it doesn't matter; we'll try again on
|
|
* the next random event.
|
|
*/
|
|
rst->state = rnd_sample_allocate_isr(rst);
|
|
}
|
|
|
|
void
|
|
rnd_add_data(rndsource_element_t *rs, void *data, u_int32_t len,
|
|
u_int32_t entropy)
|
|
{
|
|
rndsource_t *rst;
|
|
|
|
/* Mix in the random data directly into the pool. */
|
|
rndpool_add_data(&rnd_pool, data, len, entropy);
|
|
|
|
if (rs != NULL) {
|
|
rst = &rs->data;
|
|
rst->total += entropy;
|
|
|
|
if ((rst->flags & RND_FLAG_NO_ESTIMATE) == 0)
|
|
/* Estimate entropy using timing information */
|
|
rnd_add_uint32(rs, *(u_int8_t *)data);
|
|
}
|
|
|
|
/* Wake up any potential readers since we've just added some data. */
|
|
rnd_wakeup_readers();
|
|
}
|
|
|
|
/*
|
|
* Timeout, run to process the events in the ring buffer. Only one of these
|
|
* can possibly be running at a time, run at splsoftclock().
|
|
*/
|
|
static void
|
|
rnd_timeout(void *arg)
|
|
{
|
|
rnd_sample_t *sample;
|
|
rndsource_t *source;
|
|
u_int32_t entropy;
|
|
int s;
|
|
|
|
/*
|
|
* Sample queue is protected at splvm(); go there briefly to dequeue.
|
|
*/
|
|
s = splvm();
|
|
rnd_timeout_pending = 0;
|
|
|
|
sample = SIMPLEQ_FIRST(&rnd_samples);
|
|
while (sample != NULL) {
|
|
SIMPLEQ_REMOVE_HEAD(&rnd_samples, next);
|
|
splx(s);
|
|
|
|
source = sample->source;
|
|
|
|
/*
|
|
* We repeat this check here, since it is possible the source
|
|
* was disabled before we were called, but after the entry
|
|
* was queued.
|
|
*/
|
|
if ((source->flags & RND_FLAG_NO_COLLECT) == 0) {
|
|
rndpool_add_data(&rnd_pool, sample->values,
|
|
RND_SAMPLE_COUNT * 4, 0);
|
|
|
|
entropy = sample->entropy;
|
|
if (source->flags & RND_FLAG_NO_ESTIMATE)
|
|
entropy = 0;
|
|
|
|
rndpool_add_data(&rnd_pool, sample->ts,
|
|
RND_SAMPLE_COUNT * 4,
|
|
entropy);
|
|
|
|
source->total += sample->entropy;
|
|
}
|
|
|
|
rnd_sample_free(sample);
|
|
|
|
/* Go back to splvm to dequeue the next one.. */
|
|
s = splvm();
|
|
sample = SIMPLEQ_FIRST(&rnd_samples);
|
|
}
|
|
splx(s);
|
|
|
|
/*
|
|
* Wake up any potential readers waiting.
|
|
*/
|
|
rnd_wakeup_readers();
|
|
}
|
|
|
|
u_int32_t
|
|
rnd_extract_data(void *p, u_int32_t len, u_int32_t flags)
|
|
{
|
|
int retval, s;
|
|
u_int32_t c;
|
|
|
|
s = splsoftclock();
|
|
if (!rnd_have_entropy) {
|
|
#ifdef RND_VERBOSE
|
|
printf("rnd: WARNING! initial entropy low (%u).\n",
|
|
rndpool_get_entropy_count(&rnd_pool));
|
|
#endif
|
|
/* Try once again to put something in the pool */
|
|
c = rnd_counter();
|
|
rndpool_add_data(&rnd_pool, &c, sizeof(u_int32_t), 1);
|
|
}
|
|
retval = rndpool_extract_data(&rnd_pool, p, len, flags);
|
|
splx(s);
|
|
|
|
return (retval);
|
|
}
|