linux_kernel/net/xfrm/Kconfig

#
# XFRM configuration
#
config XFRM
       bool
       depends on NET
       select GRO_CELLS

config XFRM_OFFLOAD
       bool

config XFRM_ALGO
	tristate
	select XFRM
	select CRYPTO

config XFRM_USER
	tristate "Transformation user configuration interface"
	depends on INET
	select XFRM_ALGO
	---help---
	  Support for Transformation(XFRM) user configuration interface
	  like IPsec used by native Linux tools.

	  If unsure, say Y.

config XFRM_INTERFACE
	tristate "Transformation virtual interface"
	depends on XFRM && IPV6
	---help---
	  This provides a virtual interface to route IPsec traffic.

	  If unsure, say N.

config XFRM_SUB_POLICY
	bool "Transformation sub policy support"
	depends on XFRM
	---help---
	  Support sub policy for developers. By using sub policy with main
	  one, two policies can be applied to the same packet at once.
	  Policy which lives shorter time in kernel should be a sub.

	  If unsure, say N.

config XFRM_MIGRATE
	bool "Transformation migrate database"
	depends on XFRM
	---help---
	  A feature to update locator(s) of a given IPsec security
	  association dynamically.  This feature is required, for
	  instance, in a Mobile IPv6 environment with IPsec configuration
	  where mobile nodes change their attachment point to the Internet.

	  If unsure, say N.

config XFRM_STATISTICS
	bool "Transformation statistics"
	depends on INET && XFRM && PROC_FS
	---help---
	  This statistics is not a SNMP/MIB specification but shows
	  statistics about transformation error (or almost error) factor
	  at packet processing for developer.

	  If unsure, say N.

config XFRM_IPCOMP
	tristate
	select XFRM_ALGO
	select CRYPTO
	select CRYPTO_DEFLATE

config NET_KEY
	tristate "PF_KEY sockets"
	select XFRM_ALGO
	---help---
	  PF_KEYv2 socket family, compatible to KAME ones.
	  They are required if you are going to use IPsec tools ported
	  from KAME.

	  Say Y unless you know what you are doing.

config NET_KEY_MIGRATE
	bool "PF_KEY MIGRATE"
	depends on NET_KEY
	select XFRM_MIGRATE
	---help---
	  Add a PF_KEY MIGRATE message to PF_KEYv2 socket family.
	  The PF_KEY MIGRATE message is used to dynamically update
	  locator(s) of a given IPsec security association.
	  This feature is required, for instance, in a Mobile IPv6
	  environment with IPsec configuration where mobile nodes
	  change their attachment point to the Internet.  Detail
	  information can be found in the internet-draft
	  <draft-sugimoto-mip6-pfkey-migrate>.

	  If unsure, say N.