check_dup
struct interface *check_dup(naddr, naddr, naddr, int);
ifp = check_dup(ifs.int_addr,ifs.int_dstaddr,ifs.int_mask,
ifp = check_dup(gate,dst,netmask,state);
check_dup("check_dup_dir", dir_path, dir_modes, dir_modes_count);
check_dup("check_dup_file", file_path, file_modes, file_modes_count);