Decouple yarrow from random(4) device.

* Make Yarrow an optional kernel component -- enabled by "YARROW_RNG" option.
  The files sha2.c, hash.c, randomdev_soft.c and yarrow.c comprise yarrow.

* random(4) device doesn't really depend on rijndael-*.  Yarrow, however, does.

* Add random_adaptors.[ch] which is basically a store of random_adaptor's.
  random_adaptor is basically an adapter that plugs in to random(4).
  random_adaptor can only be plugged in to random(4) very early in bootup.
  Unplugging random_adaptor from random(4) is not supported, and is probably a
  bad idea anyway, due to potential loss of entropy pools.
  We currently have 3 random_adaptors:
  + yarrow
  + rdrand (ivy.c)
  + nehemeiah

* Remove platform dependent logic from probe.c, and move it into
  corresponding registration routines of each random_adaptor provider.
  probe.c doesn't do anything other than picking a specific random_adaptor
  from a list of registered ones.

* If the kernel doesn't have any random_adaptor adapters present then the
  creation of /dev/random is postponed until next random_adaptor is kldload'ed.

* Fix randomdev_soft.c to refer to its own random_adaptor, instead of a
  system wide one.

Submitted by: arthurmesh@gmail.com, obrien
Obtained from: Juniper Networks
Reviewed by: obrien

1 files changed, 66 insertions, 0 deletions

diff --git a/sys/dev/random/random_adaptors.h b/sys/dev/random/random_adaptors.h
new file mode 100644
index 000000000000..6c106df13664
--- /dev/null
+++ b/sys/dev/random/random_adaptors.h
@@ -0,0 +1,66 @@
+/*-
+ * Copyright (c) 2013 Arthur Mesh <arthurmesh@gmail.com>
+ * 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.
+ *
+ * $FreeBSD$
+ */
+
+#ifndef __RANDOM_ADAPTORS_H__
+#define __RANDOM_ADAPTORS_H__
+
+#include <sys/eventhandler.h>
+
+struct random_adaptors {
+	LIST_ENTRY(random_adaptors) entries;	/* list of providesr */
+	const char		*name;		/* name of random adaptor */
+	struct random_adaptor	*rsp;
+};
+
+struct random_adaptor *random_adaptor_get(const char *);
+int random_adaptor_register(const char *, struct random_adaptor *);
+
+/*
+ * random_adaptor's should be registered prior to
+ * random module (SI_SUB_DRIVERS/SI_ORDER_MIDDLE)
+ */
+#define RANDOM_ADAPTOR_MODULE(name, modevent, ver)		\
+    static moduledata_t name##_mod = {				\
+	#name,							\
+	modevent,						\
+	0							\
+    };								\
+    DECLARE_MODULE(name, name##_mod, SI_SUB_DRIVERS,		\
+		   SI_ORDER_SECOND);				\
+    MODULE_VERSION(name, ver);					\
+    MODULE_DEPEND(name, random, 1, 1, 1);
+
+typedef void (*random_adaptor_attach_hook)(void *, struct random_adaptor *);
+EVENTHANDLER_DECLARE(random_adaptor_attach, random_adaptor_attach_hook);
+
+/* kern.random sysctls */
+#ifdef SYSCTL_DECL	/* from sysctl.h */
+SYSCTL_DECL(_kern_random);
+#endif /* SYSCTL_DECL */
+
+#endif /* __RANDOM_ADAPTORS_H__ */