Element timeouts

The set infrastructure support establishing timeouts. A given set element which is given a timeout will be deleted from the set after the timeout expires.

Example, with per-element timeout:

% nft add table inet myfilter
% nft add set inet myfilter myset {type ipv4_addr\; flags timeout\; }
% nft add element inet myfilter myset {10.0.0.1 timeout 10s }
% nft list ruleset
table inet myfilter {
	set myset {
		type ipv4_addr
		flags timeout
		elements = { 10.0.0.1 timeout 10s expires 8s}
	}
}

timeout and expires parameters cannot be modified in this case. The element should be recreated again if you need to reset them. In order to be able to reset it from packet path among other things you can use this feature by Updating sets from the packet path.