mirror of
https://github.com/mirage/qubes-mirage-firewall.git
synced 2024-10-01 01:05:39 -04:00
107 lines
4.1 KiB
OCaml
107 lines
4.1 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 Utils
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module Netback = Netchannel.Backend.Make(Netchannel.Xenstore.Make(OS.Xs))
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module ClientEth = Ethif.Make(Netback)
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let src = Logs.Src.create "net" ~doc:"Client networking"
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module Log = (val Logs.src_log src : Logs.LOG)
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class client_iface eth ~gateway_ip ~client_ip client_mac : client_link = object
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method my_mac = ClientEth.mac eth
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method other_mac = client_mac
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method my_ip = gateway_ip
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method other_ip = client_ip
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method writev ip =
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let eth_hdr = eth_header_ipv4 ~src:(ClientEth.mac eth) ~dst:client_mac in
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ClientEth.writev eth (fixup_checksums (Cstruct.concat (eth_hdr :: ip)))
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end
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let clients : Cleanup.t IntMap.t ref = ref IntMap.empty
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(** Handle an ARP message from the client. *)
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let input_arp ~fixed_arp ~eth request =
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match Client_eth.ARP.input fixed_arp request with
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| None -> return ()
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| Some response -> ClientEth.write eth response
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(** Handle an IPv4 packet from the client. *)
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let input_ipv4 ~client_ip ~router frame packet =
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let src = Wire_structs.Ipv4_wire.get_ipv4_src packet |> Ipaddr.V4.of_int32 in
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if src = client_ip then Firewall.ipv4_from_client router frame
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else (
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Log.warn (fun f -> f "Incorrect source IP %a in IP packet from %a (dropping)"
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Ipaddr.V4.pp_hum src Ipaddr.V4.pp_hum client_ip);
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return ()
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)
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(** Connect to a new client's interface and listen for incoming frames. *)
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let add_vif { Dao.domid; device_id; client_ip } ~router ~cleanup_tasks =
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Netback.make ~domid ~device_id >>= fun backend ->
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Log.info (fun f -> f "Client %d (IP: %s) ready" domid (Ipaddr.V4.to_string client_ip));
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ClientEth.connect backend >>= or_fail "Can't make Ethernet device" >>= fun eth ->
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let client_mac = Netback.mac backend in
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let client_eth = router.Router.client_eth in
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let gateway_ip = Client_eth.client_gw client_eth in
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let iface = new client_iface eth ~gateway_ip ~client_ip client_mac in
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Router.add_client router iface;
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Cleanup.on_cleanup cleanup_tasks (fun () -> Router.remove_client router iface);
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let fixed_arp = Client_eth.ARP.create ~net:client_eth iface in
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Netback.listen backend (fun frame ->
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match Wire_structs.parse_ethernet_frame frame with
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| None -> Log.warn (fun f -> f "Invalid Ethernet frame"); return ()
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| Some (typ, _destination, payload) ->
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match typ with
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| Some Wire_structs.ARP -> input_arp ~fixed_arp ~eth payload
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| Some Wire_structs.IPv4 -> input_ipv4 ~client_ip ~router frame payload
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| Some Wire_structs.IPv6 -> return ()
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| None -> Logs.warn (fun f -> f "Unknown Ethernet type"); Lwt.return_unit
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)
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(** A new client VM has been found in XenStore. Find its interface and connect to it. *)
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let add_client ~router domid =
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let cleanup_tasks = Cleanup.create () in
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Log.info (fun f -> f "add client domain %d" domid);
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Lwt.async (fun () ->
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Lwt.catch (fun () ->
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Dao.client_vifs domid >>= function
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| [] ->
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Log.warn (fun f -> f "Client has no interfaces");
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return ()
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| vif :: others ->
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if others <> [] then Log.warn (fun f -> f "Client has multiple interfaces; using first");
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add_vif vif ~router ~cleanup_tasks
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)
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(fun ex ->
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Log.warn (fun f -> f "Error connecting client domain %d: %s"
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domid (Printexc.to_string ex));
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return ()
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)
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);
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cleanup_tasks
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(** Watch XenStore for notifications of new clients. *)
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let listen router =
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let backend_vifs = "backend/vif" in
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Log.info (fun f -> f "Watching %s" backend_vifs);
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Dao.watch_clients (fun new_set ->
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(* Check for removed clients *)
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!clients |> IntMap.iter (fun key cleanup ->
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if not (IntSet.mem key new_set) then (
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clients := !clients |> IntMap.remove key;
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Log.info (fun f -> f "client %d has gone" key);
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Cleanup.cleanup cleanup
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)
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);
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(* Check for added clients *)
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new_set |> IntSet.iter (fun key ->
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if not (IntMap.mem key !clients) then (
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let cleanup = add_client ~router key in
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clients := !clients |> IntMap.add key cleanup
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)
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)
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)
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