[PATCH] kernel: enable SRv6 support by enabling lwtunnel

[vincent at systemli.org]

From: Nick Hainke <vincent at systemli.org>

Enable the ability to use segment routing based on IPv6. It allows the
packet to specify a path that the packet should take through the network.

Lwtunnel allow an easy encapsulation of a package. You can just install
ip-full package and use it:

  ip -6 route add  2003::/64 dev eth0 encap seg6 mode encap \
    segs 2001::1,2002::2

An IPv6 package looks like this:
  [IPv6 HDR][IPv6 RH][IPv6 HDR][Data...]

Further I added netifd support:
  http://lists.openwrt.org/pipermail/openwrt-devel/
  2020-December/032467.html

Signed-off-by: Nick Hainke <vincent at systemli.org>
---
 config/Config-kernel.in | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/config/Config-kernel.in b/config/Config-kernel.in
index 1cd9da4d12..01faa5d22b 100644
--- a/config/Config-kernel.in
+++ b/config/Config-kernel.in
@@ -929,6 +929,14 @@ if KERNEL_IPV6
 		  Multicast routing requires a multicast routing daemon in
 		  addition to kernel support.
 
+	config KERNEL_IPV6_SEG6_LWTUNNEL
+		def_bool y
+		help
+		  Using lwtunnel requires full-ip package.
+
+	config KERNEL_LWTUNNEL_BPF
+		def_bool n
+
 	config KERNEL_IPV6_PIMSM_V2
 		def_bool n
 
-- 
2.29.2