int nat44_del_session (snat_main_t *sm, ip4_address_t *addr, u16 port,
snat_protocol_t proto, u32 vrf_id, int is_in);
void nat_free_session_data (snat_main_t * sm, snat_session_t * s,
int nat44_del_session (snat_main_t *sm, ip4_address_t *addr, u16 port,
snat_protocol_t proto, u32 vrf_id, int is_in);
void nat_free_session_data (snat_main_t * sm, snat_session_t * s,