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

On Wednesday 2021-09-08 04:22, Duncan Roe wrote:

quoted

quoted

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.