[RFC net-next] ipv6: ext_header: add function to handle RPL extension header option 0x63

[Andreas Bardoutsos <bardoutsos@ceid.upatras.gr>]

Signed-off-by: Andreas Bardoutsos <bardoutsos@ceid.upatras.gr>
---
Hi all!

I have added a dump function(always return true) to recognise RPL 
extension header(RFC6553)
Otherwise packet was dropped by kernel resulting in failing 
communication in RPL DAG's between
linux running border routers and devices in the graph.For example 
communication
with contiki OS running devices was previously impossible.

  include/uapi/linux/in6.h |  1 +
  net/ipv6/exthdrs.c       | 13 +++++++++++++
  2 files changed, 14 insertions(+)

diff --git a/include/uapi/linux/in6.h b/include/uapi/linux/in6.h
index 46444f8fbee4..5cc12d309dfe 100644
--- a/include/uapi/linux/in6.h
+++ b/include/uapi/linux/in6.h
@@ -146,6 +146,7 @@ struct in6_flowlabel_req {
  #define IPV6_TLV_CALIPSO	7	/* RFC 5570 */
  #define IPV6_TLV_JUMBO		194
  #define IPV6_TLV_HAO		201	/* home address option */
+#define IPV6_TLV_RPL	99	/* RFC 6553 */

  /*
   *	IPV6 socket options
diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c
index b636f1da9aec..82ed60d3180e 100644
--- a/net/ipv6/exthdrs.c
+++ b/net/ipv6/exthdrs.c
@@ -785,6 +785,15 @@ static bool ipv6_hop_calipso(struct sk_buff *skb, 
int optoff)
  	return false;
  }

+/* RPL RFC 6553 */
+
+static bool ipv6_hop_rpl(struct sk_buff *skb, int optoff)
+{
+	/*Dump function which always return true
+	*when rpl option is detected*/
+	return true;
+}
+
  static const struct tlvtype_proc tlvprochopopt_lst[] = {
  	{
  		.type	= IPV6_TLV_ROUTERALERT,
@@ -798,6 +807,10 @@ static const struct tlvtype_proc 
tlvprochopopt_lst[] = {
  		.type	= IPV6_TLV_CALIPSO,
  		.func	= ipv6_hop_calipso,
  	},
+	{
+		.type	= IPV6_TLV_RPL,
+		.func	= ipv6_hop_rpl,
+	},
  	{ -1, }
  };