ipv6: ioam: Add support for the ip6ip6 encapsulation

This patch adds support for the ip6ip6 encapsulation by providing three encap
modes: inline, encap and auto.

Signed-off-by: Justin Iurman <justin.iurman@uliege.be>
Signed-off-by: David S. Miller <davem@davemloft.net>

Author: IurmanJ

include/uapi/linux/ioam6_iptunnel.h

@@ -9,9 +9,38 @@
 #ifndef _UAPI_LINUX_IOAM6_IPTUNNEL_H
 #define _UAPI_LINUX_IOAM6_IPTUNNEL_H
 
+/* Encap modes:
+ *  - inline: direct insertion
+ *  - encap: ip6ip6 encapsulation
+ *  - auto: inline for local packets, encap for in-transit packets
+ */
+enum {
+	__IOAM6_IPTUNNEL_MODE_MIN,
+
+	IOAM6_IPTUNNEL_MODE_INLINE,
+	IOAM6_IPTUNNEL_MODE_ENCAP,
+	IOAM6_IPTUNNEL_MODE_AUTO,
+
+	__IOAM6_IPTUNNEL_MODE_MAX,
+};
+
+#define IOAM6_IPTUNNEL_MODE_MIN (__IOAM6_IPTUNNEL_MODE_MIN + 1)
+#define IOAM6_IPTUNNEL_MODE_MAX (__IOAM6_IPTUNNEL_MODE_MAX - 1)
+
 enum {
 	IOAM6_IPTUNNEL_UNSPEC,
+
+	/* Encap mode */
+	IOAM6_IPTUNNEL_MODE,		/* u8 */
+
+	/* Tunnel dst address.
+	 * For encap,auto modes.
+	 */
+	IOAM6_IPTUNNEL_DST,		/* struct in6_addr */
+
+	/* IOAM Trace Header */
 	IOAM6_IPTUNNEL_TRACE,		/* struct ioam6_trace_hdr */
+
 	__IOAM6_IPTUNNEL_MAX,
 };
 

net/ipv6/Kconfig

@@ -332,10 +332,10 @@ config IPV6_IOAM6_LWTUNNEL
 	bool "IPv6: IOAM Pre-allocated Trace insertion support"
 	depends on IPV6
 	select LWTUNNEL
+	select DST_CACHE
 	help
-	  Support for the inline insertion of IOAM Pre-allocated
-	  Trace Header (only on locally generated packets), using
-	  the lightweight tunnels mechanism.
+	  Support for the insertion of IOAM Pre-allocated Trace
+	  Header using the lightweight tunnels mechanism.
 
 	  If unsure, say N.