1 files changed, 37 insertions, 0 deletions
diff --git a/7/firewall.pl b/7/firewall.pl
new file mode 100644
index 0000000..9bb0cc2
--- /dev/null
+++ b/7/firewall.pl
@@ -0,0 +1,37 @@
+% 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([]).