ipv6 sit: 6rd (IPv6 Rapid Deployment) Support.

IPv6 Rapid Deployment (6rd; draft-ietf-softwire-ipv6-6rd) builds upon
mechanisms of 6to4 (RFC3056) to enable a service provider to rapidly
deploy IPv6 unicast service to IPv4 sites to which it provides
customer premise equipment.  Like 6to4, it utilizes stateless IPv6 in
IPv4 encapsulation in order to transit IPv4-only network
infrastructure.  Unlike 6to4, a 6rd service provider uses an IPv6
prefix of its own in place of the fixed 6to4 prefix.

With this option enabled, the SIT driver offers 6rd functionality by
providing additional ioctl API to configure the IPv6 Prefix for in
stead of static 2002::/16 for 6to4.

Original patch was done by Alexandre Cassen <acassen@freebox.fr>
based on old Internet-Draft.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/Kconfig

@@ -170,6 +170,25 @@ config IPV6_SIT
 
 	  Saying M here will produce a module called sit. If unsure, say Y.
 
+config IPV6_SIT_6RD
+	bool "IPv6: IPv6 Rapid Development (6RD) (EXPERIMENTAL)"
+	depends on IPV6_SIT && EXPERIMENTAL
+	default n
+	---help---
+	  IPv6 Rapid Deployment (6rd; draft-ietf-softwire-ipv6-6rd) builds upon
+	  mechanisms of 6to4 (RFC3056) to enable a service provider to rapidly
+	  deploy IPv6 unicast service to IPv4 sites to which it provides
+	  customer premise equipment.  Like 6to4, it utilizes stateless IPv6 in
+	  IPv4 encapsulation in order to transit IPv4-only network
+	  infrastructure.  Unlike 6to4, a 6rd service provider uses an IPv6
+	  prefix of its own in place of the fixed 6to4 prefix.
+
+	  With this option enabled, the SIT driver offers 6rd functionality by
+	  providing additional ioctl API to configure the IPv6 Prefix for in
+	  stead of static 2002::/16 for 6to4.
+
+	  If unsure, say N.
+
 config IPV6_NDISC_NODETYPE
 	bool