% vim set ft=prolog

% rule(src, dst, proto, port, source(..)).

:- module(firewall, [
    %fw_rule/2,
    warning/1,
    retract_all_from/1]).

:- use_module(library(assoc)).
:- use_module(library(dcgs)).

:- use_module(hosts, [
    router_link/3]).

:- dynamic(fw_rule/2).

warning(Msg) :-
    fw_rule(Host, Attr),
    \+ get_assoc("from", Attr, _),
    format("Missing 'from' on fw_rule for host '~w', ~w", [Host, Attr], Msg).

rules_from(From, Rules) :-
    findall(
        fw_rule(H, Attr), 
        (
          fw_rule(H, Attr),
          get_assoc("from", Attr, From)
        ),
        Rules).

retract_all_from(From) :-
    rules_from(From, Rules),
    retract_rules(Rules).

retract_rules([R|Rules]) :- retract(R), retract_rules(Rules).
retract_rules([]).