Re: [PATCH 3/8] [NETFILTER]: rename NF_ARP to NFPROTO_ARP and assign a non-clashing value

[Patrick McHardy <kaber@trash.net>]

Jan Engelhardt wrote:
> On Wednesday 2008-04-09 15:12, Patrick McHardy wrote
>>
>>>> The array declarations should then use NFPROTO_MAX + 1.
>>> Why +1 if MAX is ARP?
>> Because array indices start at zero.
>>
> 
> It's all whacked up, srsly.
> 
> #define AF_RXRPC 33
> #define AF_MAX   34
> 
> IMHO we should just:
> 
> enum {
> 	NFPROTO_FOO = AF_MAX,
> 	NFPROTO_BAR,
> 	NFPROTO_BAZ,
> 	NFPROTO_MAX,
> };
> 
> and use NFPROTO_MAX in lieu of AF_MAX where due.
> Putting that into place with ARP means:
> 
> enum {
> 	NFPROTO_ARP = AF_MAX,
> 	NFPROTO_MAX,
> };
> 
> and use NFPROTO_MAX. No __NFPROTO_MIN, no __NFPROTO_MAX, and
> less confusion overall. How about it? :)

The decoupling of netfilter supported protocols from AF values
makes sense.

However I think _MAX definitions actually having the value MAX + 1
is pretty poor style. When you see an array dimensioned as
[XYZ_MAX] you always have to check whether it is really the maximum
(and thus a bug) or maximum + 1. So I'd prefer to have MAX really
be the maximum and use max + 1 for arrays etc.