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(* Copyright (C) 2015, Thomas Leonard <thomas.leonard@unikernel.com>
See the README file for details. *)
(** Put your firewall rules here. *)
open Packet
(* OCaml normally warns if you don't match all fields, but that's OK here. *)
[@@@ocaml.warning "-9"]
(** {2 Actions}
The possible actions are:
- [`Accept] : Send the packet to its destination.
- [`NAT] : Rewrite the packet's source field so packet appears to
have come from the firewall, via an unused port.
Also, add NAT rules so related packets will be translated accordingly.
- [`NAT_to (host, port)] :
As for [`NAT], but also rewrite the packet's destination fields so it
will be sent to [host:port].
- [`Drop reason] drop the packet and log the reason.
*)
(** Decide what to do with a packet from a client VM.
Note: If the packet matched an existing NAT rule then this isn't called. *)
let from_client = function
| { dst = (`External _ | `NetVM) } -> `NAT
| { dst = `Client_gateway; proto = `UDP { dport = 53 } } -> `NAT_to (`NetVM, 53)
| { dst = (`Client_gateway | `Firewall_uplink) } -> `Drop "packet addressed to firewall itself"
| { dst = `Client _ } -> `Drop "prevent communication between client VMs"
(** Decide what to do with a packet received from the outside world.
Note: If the packet matched an existing NAT rule then this isn't called. *)
let from_netvm = function
| _ -> `Drop "drop by default"