flow_dissector: Add control/reporting of encapsulation

Add an input flag to flow dissector on rather dissection should stop
when encapsulation is detected (IP/IP or GRE). Also, add a key_control
flag that indicates encapsulation was encountered during the
dissection.

Signed-off-by: Tom Herbert <tom@herbertland.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/flow_dissector.h b/include/net/flow_dissector.h
index 66dbc34..bddd108 100644
--- a/include/net/flow_dissector.h
+++ b/include/net/flow_dissector.h
@@ -14,6 +14,7 @@
 	u16	addr_type;
 	u32	is_fragment:1;
 	u32	first_frag:1;
+	u32	encapsulation:1;
 };
 
 /**
@@ -127,6 +128,7 @@
 #define FLOW_DISSECTOR_F_PARSE_1ST_FRAG		BIT(0)
 #define FLOW_DISSECTOR_F_STOP_AT_L3		BIT(1)
 #define FLOW_DISSECTOR_F_STOP_AT_FLOW_LABEL	BIT(2)
+#define FLOW_DISSECTOR_F_STOP_AT_ENCAP		BIT(3)
 
 struct flow_dissector_key {
 	enum flow_dissector_key_id key_id;