mirror of
https://github.com/mirage/qubes-mirage-firewall.git
synced 2024-12-26 23:59:39 -05:00
93b92c041b
allow pick_free_port to fail reserve a special udp port for dns (as last resort)
95 lines
3.3 KiB
OCaml
95 lines
3.3 KiB
OCaml
(* Copyright (C) 2015, Thomas Leonard <thomas.leonard@unikernel.com>
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See the README file for details. *)
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open Lwt.Infix
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open Fw_utils
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module Eth = Ethernet.Make(Netif)
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let src = Logs.Src.create "uplink" ~doc:"Network connection to NetVM"
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module Log = (val Logs.src_log src : Logs.LOG)
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module Make (R:Mirage_random.S) (Clock : Mirage_clock.MCLOCK) (Time : Mirage_time.S) = struct
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module Arp = Arp.Make(Eth)(Time)
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module I = Static_ipv4.Make(R)(Clock)(Eth)(Arp)
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module U = Udp.Make(I)(R)
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type t = {
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net : Netif.t;
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eth : Eth.t;
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arp : Arp.t;
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interface : interface;
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mutable fragments : Fragments.Cache.t;
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ip : I.t;
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udp: U.t;
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}
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class netvm_iface eth mac ~my_ip ~other_ip : interface = object
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method my_mac = Eth.mac eth
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method my_ip = my_ip
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method other_ip = other_ip
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method writev ethertype fillfn =
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mac >>= fun dst ->
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Eth.write eth dst ethertype fillfn >|= or_raise "Write to uplink" Eth.pp_error
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end
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let send_dns_client_query t ~src_port ~dst ~dst_port buf =
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U.write ~src_port ~dst ~dst_port t.udp buf >|= function
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| Error s -> Log.err (fun f -> f "error sending udp packet: %a" U.pp_error s); Error (`Msg "failure")
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| Ok () -> Ok ()
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let listen t get_ts dns_responses router =
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let handle_packet ip_header ip_packet =
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let open Udp_packet in
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Log.debug (fun f -> f "received ipv4 packet from %a on uplink" Ipaddr.V4.pp ip_header.Ipv4_packet.src);
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match ip_packet with
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| `UDP (header, packet) when My_nat.dns_port router.Router.nat header.dst_port ->
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Log.debug (fun f -> f "found a DNS packet whose dst_port (%d) was in the list of dns_client ports" header.dst_port);
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Lwt_mvar.put dns_responses (header, packet)
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| _ ->
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Firewall.ipv4_from_netvm router (`IPv4 (ip_header, ip_packet))
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in
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Netif.listen t.net ~header_size:Ethernet.Packet.sizeof_ethernet (fun frame ->
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(* Handle one Ethernet frame from NetVM *)
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Eth.input t.eth
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~arpv4:(Arp.input t.arp)
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~ipv4:(fun ip ->
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let cache, r =
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Nat_packet.of_ipv4_packet t.fragments ~now:(get_ts ()) ip
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in
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t.fragments <- cache;
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match r with
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| Error e ->
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Log.warn (fun f -> f "Ignored unknown IPv4 message from uplink: %a" Nat_packet.pp_error e);
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Lwt.return ()
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| Ok None -> Lwt.return_unit
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| Ok (Some (`IPv4 (header, packet))) -> handle_packet header packet
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)
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~ipv6:(fun _ip -> Lwt.return_unit)
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frame
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) >|= or_raise "Uplink listen loop" Netif.pp_error
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let interface t = t.interface
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let connect config =
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let my_ip = config.Dao.uplink_our_ip in
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let gateway = config.Dao.uplink_netvm_ip in
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Netif.connect "0" >>= fun net ->
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Eth.connect net >>= fun eth ->
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Arp.connect eth >>= fun arp ->
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Arp.add_ip arp my_ip >>= fun () ->
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let cidr = Ipaddr.V4.Prefix.make 0 my_ip in
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I.connect ~cidr ~gateway eth arp >>= fun ip ->
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U.connect ip >>= fun udp ->
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let netvm_mac =
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Arp.query arp gateway
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>|= or_raise "Getting MAC of our NetVM" Arp.pp_error in
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let interface = new netvm_iface eth netvm_mac
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~my_ip
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~other_ip:config.Dao.uplink_netvm_ip in
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let fragments = Fragments.Cache.empty (256 * 1024) in
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Lwt.return { net; eth; arp; interface ; fragments ; ip ; udp }
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end
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