Re: [nft PATCH v3] expression: print sets and maps in pretty format

[Pablo Neira Ayuso <pablo@netfilter.org>]

On Tue, May 02, 2017 at 11:47:02AM +0200, Arturo Borrero Gonzalez wrote:
> Print elements per line instead of all in a single line.
> The elements which can be 'short' are printed 5 per line,
> and others, like IPv4 addresses are printed 2 per line.
> 
> Example:
> 
> % nft list ruleset -nnn
> table ip t {
> 	set s {
> 		type inet_service
> 		elements = { 1, 2, 3, 4, 10,
> 			     432, 433, 434, 435, 436,
> 			     437, 438, 439, 440, 441,
> 			     442, 443, 444, 445, 446,
> 			     447, 448, 449, 450, 12345 }
> 	}
> 
> 	map m {
> 		type inet_service . iface_index : verdict
> 		elements = { 123 . "lo" : accept,
> 			     1234 . "lo" : accept,
> 			     12345 . "lo" : accept,
> 			     12346 . "lo" : accept,
> 			     12347 . "lo" : accept }
> 	}
> 
> 	set s3 {
> 		type ipv4_addr
> 		elements = { 1.1.1.1, 2.2.2.2,
> 			     3.3.3.3 }
> 	}
> }

Applied.

It would be really great if someone can just fetch the column length
from the terminal via ioctl(), then do poor man adjustment, eg.

Assuming ipv4 address maximum length is:

        strlen("255.255.255.255");

then, divide the column length by this, so we fit as many elements as
possible by this. And so on, for each datatype.