+#include <nat/lib/inlines.h>
+
+typedef struct
+{
+ u16 identifier;
+ u16 sequence;
+} echo_header_t;
+
+/* session key (4-tuple) */
+typedef struct
+{
+ union
+ {
+ struct
+ {
+ ip4_address_t addr;
+ u16 port;
+ u16 protocol:3, fib_index:13;
+ };
+ u64 as_u64;
+ };
+} nat_session_key_t;