Re: [PATCH net v2] net: netfilter: Fix port selection of FTP for NF_NAT_RANGE_PROTO_SPECIFIED

[Jan Engelhardt]

On Wednesday 2021-09-08 04:22, Duncan Roe wrote:
>> >Either use if (nat->range_info.min_proto.all || ...
>> >
>> >or use ntohs().  I will leave it up to you if you prefer
>> >ntohs(nat->range_info.min_proto.all) == 0 or
>> >nat->range_info.min_proto.all == ntohs(0).
>>
>> If one has the option, one should always prefer to put htons/htonl on
>> the side with the constant literal;
>> Propagation of constants and compile-time evaluation is the target.
>>
>> That works for some other functions as well (e.g.
>> strlen("fixedstring")).
>
>When comparing against constant zero, why use htons/htonl at all?

Logical correctness.
Remember, it was the sparse tool that complained in the first place.