[XFRM] STATE: Introduce route optimization mode.

Route optimization is used with routing header and destination options
header for Mobile IPv6.

At outbound it makes header space like IPsec transport. At inbound it
does nothing because exhdrs.c functions have responsibility to update
skbuff information for these headers.

Signed-off-by: Masahide NAKAMURA <nakam@linux-ipv6.org>
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/Kconfig b/net/ipv6/Kconfig
index 14f0b33..1188d95 100644
--- a/net/ipv6/Kconfig
+++ b/net/ipv6/Kconfig
@@ -127,6 +127,13 @@
 
 	  If unsure, say Y.
 
+config INET6_XFRM_MODE_ROUTEOPTIMIZATION
+	tristate "IPv6: MIPv6 route optimization mode (EXPERIMENTAL)"
+	depends on IPV6 && EXPERIMENTAL
+	select XFRM
+	---help---
+	  Support for MIPv6 route optimization mode.
+
 config IPV6_TUNNEL
 	tristate "IPv6: IPv6-in-IPv6 tunnel"
 	select INET6_TUNNEL