session_t *session_lookup_safe4 (u32 fib_index, ip4_address_t * lcl,
ip4_address_t * rmt, u16 lcl_port,
u16 rmt_port, u8 proto);
session_t *session_lookup_safe4 (u32 fib_index, ip4_address_t * lcl,
ip4_address_t * rmt, u16 lcl_port,
u16 rmt_port, u8 proto);