WIP: add a compile.ml file

compile.ml

@@ -1,37 +1,109 @@
-open Config
+open Ipaddr
 
-let rec deps_of_zone = function
-  | ZoneIpv4 _ | ZoneIpv6 _ -> []
-  | Zone z -> [z]
-  | ZoneList l -> List.flatten (List.map deps_of_zone l)
-  | ZoneExclude e -> deps_of_zone e
+module Prefix = struct
+  type t = Ipv4 of V4.Prefix.t | Ipv6 of V6.Prefix.t | Not of t
 
-let deps_of_zones zone =
-  List.map (fun (a, b) -> (a, deps_of_zone b)) zone
+  let rec compare a b =
+    match (a, b) with
+    | Ipv4 a, Ipv4 b -> V4.Prefix.compare a b
+    | Ipv6 a, Ipv6 b -> V6.Prefix.compare a b
+    | Ipv6 _, _ -> 1
+    | _, Ipv6 _ -> -1
+    | Not a, Not b -> -compare a b
+    | Not _, _ -> -1
+    | _, Not _ -> 1
+end
 
-let compile_zone _ _ = []
+module PrefixSet = struct
+  include Stdlib.Set.Make (Prefix)
+
+  let of_addrs zones =
+    let open Config in
+    function
+    | Addrs.Name name -> (
+        match List.assoc_opt name zones with
+        | Some set -> set
+        | None -> failwith ("zone " ^ name ^ " not found"))
+    | Addrs.Ipv4 prefix -> singleton (Prefix.Ipv4 prefix)
+    | Addrs.Ipv6 prefix -> singleton (Prefix.Ipv6 prefix)
+
+  let of_addrs_list zone =
+    List.fold_left (fun acc addrs -> union (of_addrs zone addrs) acc) empty
+end
+
+let rec zone_deps =
+  let open Config.Zone in
+  function
+  | Ipv4 _ | Ipv6 _ -> []
+  | Name name -> [ name ]
+  | List list -> List.flatten (List.map zone_deps list)
+  | Not not -> zone_deps not
+
+let zones_deps zone = List.map (fun (k, v) -> (k, zone_deps v)) zone
+
+let rec compile_zone assoc =
+  let open Config.Zone in
+  function
+  | Ipv4 ipv4 -> PrefixSet.singleton (Prefix.Ipv4 ipv4)
+  | Ipv6 ipv6 -> PrefixSet.singleton (Prefix.Ipv6 ipv6)
+  | Name name -> List.assoc name assoc
+  | List list ->
+      List.fold_left
+        (fun acc zone -> PrefixSet.union (compile_zone assoc zone) acc)
+        PrefixSet.empty list
+  | Not zone -> PrefixSet.map (fun p -> Prefix.Not p) (compile_zone assoc zone)
 
 let compile_zones zones =
-  let deps = deps_of_zones zones in
-  match Tsort.sort deps with
+  match Tsort.sort (zones_deps zones) with
   | Tsort.Sorted sorted ->
-    List.fold_right (fun name acc ->
-        let values = List.assoc name zones in
-        let compiled = compile_zone acc values in
-        (name, compiled) :: acc) sorted []
+      List.fold_right
+        (fun name acc ->
+          let zone = List.assoc name zones in
+          let compiled = compile_zone acc zone in
+          (name, compiled) :: acc)
+        sorted []
   | _ -> assert false
 
-let compile_rule zones { src; dest; l4 } =
-  let match_src = match src with
-    | [] -> []
-    | l -> []
+let find_ipv4 zones negate addrs_list =
+  let open Prefix in
+  let prefixes = PrefixSet.of_addrs_list zones addrs_list in
+  let rec filter_prefix negate prefix acc =
+    match prefix with
+    | Ipv4 ipv4 -> if negate then acc else ipv4 :: acc
+    | Ipv6 _ -> acc
+    | Not prefix -> filter_prefix (not negate) prefix acc
   in
-  let match_dest = match dest with
-    | [] -> []
-    | l -> []
-  in
-  let l4_rules = compile_l4 zones l4 in
-  List.flatten [match_src; match_dest; l4_rules]
+  PrefixSet.fold (filter_prefix negate) prefixes []
 
-let compile_rules zones =
-  List.map (compile_rule zones)
+let compile_addrs_ipv4 zones field addrs =
+  let open Nftables in
+  let equal = find_ipv4 zones false addrs |> List.map (fun p -> Expr.Ipv4 p) in
+  let not_equal =
+    find_ipv4 zones true addrs |> List.map (fun p -> Expr.Ipv4 p)
+  in
+  (* TODO: handle empty sets *)
+  [
+    Stmt.Match (Match.Eq, Expr.Payload (Payload.Ipv4 field), Expr.Set equal);
+    Stmt.Match
+      (Match.NotEq, Expr.Payload (Payload.Ipv4 field), Expr.Set not_equal);
+  ]
+
+let compile_rule zones rule =
+  let open Config.Rule in
+  let open Nftables in
+  let ipv4_src = compile_addrs_ipv4 zones Payload.Ipv4.Saddr rule.src in
+  let ipv4_dest = compile_addrs_ipv4 zones Payload.Ipv4.Daddr rule.dest in
+  List.flatten [ ipv4_src; ipv4_dest ]
+
+let compile config =
+  let open Nftables in
+  let open Config in
+  let zones = compile_zones config.zones in
+  let exprs = List.map (compile_rule zones) config.rules in
+  let family = Family.Inet in
+  let table = "filter" in
+  let chain = "forward" in
+  let compiled =
+    List.map (fun expr -> Command.AddRule { family; table; chain; expr }) exprs
+  in
+  Command.FlushRuleset :: compiled

firewall.ml

@@ -1,25 +1,6 @@
-open Nftables
+let json = Yojson.Basic.from_file "config.json"
+let config = Config.of_json json
+let compiled = Compile.compile config
+let nftables = Nftables.to_json compiled
 
-let nftables = [
-  Flush FlushRuleset;
-  Add (AddRule {
-      family = Inet;
-      table = "filter";
-      chain = "forward";
-      expr =
-        [
-          Log { prefix = Some "test"; group = None };
-          Match {
-            left = Payload (Udp UdpSport);
-            right = Set [Number 53];
-            op = NotEq };
-          Verdict Accept
-        ]
-    })
-]
-
-let json = json_of_nftables nftables
-
-let () =
-  print_string (Yojson.Basic.to_string json);
-  print_newline ()
+let () = Format.printf "%s\n" (Yojson.Basic.pretty_to_string nftables)