1 files changed, 251 insertions, 0 deletions
diff --git a/sys/dev/random/random_harvestq.c b/sys/dev/random/random_harvestq.c
new file mode 100644
index 0000000..fc87cde
--- /dev/null
+++ b/sys/dev/random/random_harvestq.c
@@ -0,0 +1,251 @@
+/*-
+ * Copyright (c) 2013 Arthur Mesh
+ * Copyright (c) 2000-2009 Mark R V Murray
+ * Copyright (c) 2004 Robert N. M. Watson
+ * 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.
+ *
+ * $FreeBSD$
+ */
+
+#include <sys/cdefs.h>
+__FBSDID("$FreeBSD$");
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/kernel.h>
+#include <sys/kthread.h>
+#include <sys/lock.h>
+#include <sys/malloc.h>
+#include <sys/mutex.h>
+#include <sys/random.h>
+#include <sys/sysctl.h>
+#include <sys/unistd.h>
+
+#include <dev/random/randomdev_soft.h>
+
+#include "random_harvestq.h"
+
+#define RANDOM_FIFO_MAX	256	/* How many events to queue up */
+
+MALLOC_DEFINE(M_ENTROPY, "entropy", "Entropy harvesting buffers");
+
+/*
+ * The harvest mutex protects the consistency of the entropy fifos and
+ * empty fifo.
+ */
+struct mtx	harvest_mtx;
+
+/* Lockable FIFO queue holding entropy buffers */
+struct entropyfifo {
+	int count;
+	STAILQ_HEAD(harvestlist, harvest) head;
+};
+
+/* Empty entropy buffers */
+static struct entropyfifo emptyfifo;
+
+#define EMPTYBUFFERS	1024
+
+/* Harvested entropy */
+static struct entropyfifo harvestfifo[ENTROPYSOURCE];
+
+/* <0 to end the kthread, 0 to let it run, 1 to flush the harvest queues */
+int random_kthread_control = 0;
+
+static struct proc *random_kthread_proc;
+
+static void
+random_kthread(void *arg)
+{
+	STAILQ_HEAD(, harvest) local_queue;
+	struct harvest *event = NULL;
+	int local_count;
+	enum esource source;
+	event_proc_f func = arg;
+
+	STAILQ_INIT(&local_queue);
+	local_count = 0;
+
+	/* Process until told to stop */
+	mtx_lock_spin(&harvest_mtx);
+	for (; random_kthread_control >= 0;) {
+
+		/* Cycle through all the entropy sources */
+		for (source = RANDOM_START; source < ENTROPYSOURCE; source++) {
+			/*
+			 * Drain entropy source records into a thread-local
+			 * queue for processing while not holding the mutex.
+			 */
+			STAILQ_CONCAT(&local_queue, &harvestfifo[source].head);
+			local_count += harvestfifo[source].count;
+			harvestfifo[source].count = 0;
+		}
+
+		/*
+		 * Deal with events, if any, dropping the mutex as we process
+		 * each event.  Then push the events back into the empty
+		 * fifo.
+		 */
+		if (!STAILQ_EMPTY(&local_queue)) {
+			mtx_unlock_spin(&harvest_mtx);
+			STAILQ_FOREACH(event, &local_queue, next)
+				func(event);
+			mtx_lock_spin(&harvest_mtx);
+			STAILQ_CONCAT(&emptyfifo.head, &local_queue);
+			emptyfifo.count += local_count;
+			local_count = 0;
+		}
+
+		KASSERT(local_count == 0, ("random_kthread: local_count %d",
+		    local_count));
+
+		/*
+		 * If a queue flush was commanded, it has now happened,
+		 * and we can mark this by resetting the command.
+		 */
+		if (random_kthread_control == 1)
+			random_kthread_control = 0;
+
+		/* Work done, so don't belabour the issue */
+		msleep_spin_sbt(&random_kthread_control, &harvest_mtx,
+		    "-", SBT_1S / 10, 0, C_PREL(1));
+
+	}
+	mtx_unlock_spin(&harvest_mtx);
+
+	random_set_wakeup_exit(&random_kthread_control);
+	/* NOTREACHED */
+}
+
+void
+random_harvestq_init(event_proc_f cb)
+{
+	int error, i;
+	struct harvest *np;
+	enum esource e;
+
+	/* Initialise the harvest fifos */
+	STAILQ_INIT(&emptyfifo.head);
+	emptyfifo.count = 0;
+	for (i = 0; i < EMPTYBUFFERS; i++) {
+		np = malloc(sizeof(struct harvest), M_ENTROPY, M_WAITOK);
+		STAILQ_INSERT_TAIL(&emptyfifo.head, np, next);
+	}
+	for (e = RANDOM_START; e < ENTROPYSOURCE; e++) {
+		STAILQ_INIT(&harvestfifo[e].head);
+		harvestfifo[e].count = 0;
+	}
+
+	mtx_init(&harvest_mtx, "entropy harvest mutex", NULL, MTX_SPIN);
+
+
+	/* Start the hash/reseed thread */
+	error = kproc_create(random_kthread, cb,
+	    &random_kthread_proc, RFHIGHPID, 0, "rand_harvestq"); /* RANDOM_CSPRNG_NAME */
+
+	if (error != 0)
+		panic("Cannot create entropy maintenance thread.");
+}
+
+void
+random_harvestq_deinit(void)
+{
+	struct harvest *np;
+	enum esource e;
+
+	/* Destroy the harvest fifos */
+	while (!STAILQ_EMPTY(&emptyfifo.head)) {
+		np = STAILQ_FIRST(&emptyfifo.head);
+		STAILQ_REMOVE_HEAD(&emptyfifo.head, next);
+		free(np, M_ENTROPY);
+	}
+	for (e = RANDOM_START; e < ENTROPYSOURCE; e++) {
+		while (!STAILQ_EMPTY(&harvestfifo[e].head)) {
+			np = STAILQ_FIRST(&harvestfifo[e].head);
+			STAILQ_REMOVE_HEAD(&harvestfifo[e].head, next);
+			free(np, M_ENTROPY);
+		}
+	}
+
+	mtx_destroy(&harvest_mtx);
+}
+
+/*
+ * Entropy harvesting routine. This is supposed to be fast; do
+ * not do anything slow in here!
+ */
+void
+random_harvestq_internal(u_int64_t somecounter, const void *entropy,
+    u_int count, u_int bits, u_int frac, enum esource origin)
+{
+	struct harvest *event;
+
+	KASSERT(origin >= RANDOM_START && origin <= RANDOM_PURE,
+	    ("random_harvest_internal: origin %d invalid\n", origin));
+
+	/* Lockless read to avoid lock operations if fifo is full. */
+	if (harvestfifo[origin].count >= RANDOM_FIFO_MAX)
+		return;
+
+	mtx_lock_spin(&harvest_mtx);
+
+	/*
+	 * Don't make the harvest queues too big - help to prevent low-grade
+	 * entropy swamping
+	 */
+	if (harvestfifo[origin].count < RANDOM_FIFO_MAX) {
+		event = STAILQ_FIRST(&emptyfifo.head);
+		if (event != NULL) {
+			/* Add the harvested data to the fifo */
+			STAILQ_REMOVE_HEAD(&emptyfifo.head, next);
+			harvestfifo[origin].count++;
+			event->somecounter = somecounter;
+			event->size = count;
+			event->bits = bits;
+			event->frac = frac;
+			event->source = origin;
+
+			/* XXXX Come back and make this dynamic! */
+			count = MIN(count, HARVESTSIZE);
+			memcpy(event->entropy, entropy, count);
+
+#if 0
+			{
+			int i;
+			printf("Harvest:%16jX ", event->somecounter);
+			for (i = 0; i < event->size; i++)
+				printf("%02X", event->entropy[i]);
+			for (; i < 16; i++)
+				printf("  ");
+			printf(" %2d 0x%2X.%03X %02X\n", event->size, event->bits, event->frac, event->source);
+			}
+#endif
+
+			STAILQ_INSERT_TAIL(&harvestfifo[origin].head,
+			    event, next);
+		}
+	}
+	mtx_unlock_spin(&harvest_mtx);
+}
+