Tag based on variables

It's possible to generate tags based on these variables:

$if - The interface.

$srcaddr - The source IP address.

$dstaddr - The destination IP address.

$srcport - The source port specification.

$dstport - The destination port specification.

$proto - The protocol name.

$nr - The rule number.

pass in on $int_if from $int_if:network tag "$srcaddr-$if-$nr"
# [ ... ]
pass out on $ext_if tagged "2001:16d8:ccbc:baad::/64-ral0-0"

NOTE: These expand at ruleset load time.