- @param is_add - 1 if add, 0 if delete
- @param addr_only - 1 if address only mapping
+ @param is_add - true if add, false if delete
+ @param flags - flag NAT_IS_ADDR_ONLY if address only mapping,
+ flag nat_is_twice_nat if nat address range for external hosts,
+ flag NAT_IS_SELF_TWICE_NAT if translate external host address
+ and port whenever external host address equals local
+ address of internal host,
+ flag NAT_IS_OUT2IN_ONLY if rule match only out2in direction