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, 1 insertions, 1 deletions

diff --git a/sys/i386/conf/XEN b/sys/i386/conf/XEN
index bcc9f19..f90dd81 100644
--- a/sys/i386/conf/XEN
+++ b/sys/i386/conf/XEN
@@ -76,6 +76,7 @@ device		pci
 # Pseudo devices.
 device		loop		# Network loopback
 device		random		# Entropy device
+options 	YARROW_RNG	# Yarrow software RNG
 device		ether		# Ethernet support
 device		tun		# Packet tunnel.
 device		md		# Memory "disks"
@@ -90,4 +91,3 @@ options		AH_SUPPORT_AR5416
 # Be aware of the administrative consequences of enabling this!
 # Note that 'bpf' is required for DHCP.
 device		bpf		# Berkeley packet filter
-