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(* Copyright (C) 2015, Thomas Leonard <thomas.leonard@unikernel.com>
See the README file for details. *)
open Lwt.Infix
open Fw_utils
module Netback = Netchannel.Backend.Make(Netchannel.Xenstore.Make(OS.Xs))
module ClientEth = Ethif.Make(Netback)
let src = Logs.Src.create "client_net" ~doc:"Client networking"
module Log = (val Logs.src_log src : Logs.LOG)
let writev eth data =
Lwt.catch
(fun () ->
ClientEth.writev eth data >|= function
| Ok () -> ()
| Error e ->
Log.err (fun f -> f "error trying to send to client:@\n@[<v2> %a@]@\nError: @[%a@]"
Cstruct.hexdump_pp (Cstruct.concat data) ClientEth.pp_error e);
)
(fun ex ->
(* Usually Netback_shutdown, because the client disconnected *)
Log.err (fun f -> f "uncaught exception trying to send to client:@\n@[<v2> %a@]@\nException: @[%s@]"
Cstruct.hexdump_pp (Cstruct.concat data) (Printexc.to_string ex));
Lwt.return ()
)
class client_iface eth ~gateway_ip ~client_ip client_mac : client_link = object
val queue = FrameQ.create (Ipaddr.V4.to_string client_ip)
method my_mac = ClientEth.mac eth
method other_mac = client_mac
method my_ip = gateway_ip
method other_ip = client_ip
method writev proto ip =
FrameQ.send queue (fun () ->
let eth_hdr = eth_header proto ~src:(ClientEth.mac eth) ~dst:client_mac in
writev eth (eth_hdr :: ip)
)
end
let clients : Cleanup.t Dao.VifMap.t ref = ref Dao.VifMap.empty
(** Handle an ARP message from the client. *)
let input_arp ~fixed_arp ~iface request =
match Arpv4_packet.Unmarshal.of_cstruct request with
| Error e ->
Log.warn (fun f -> f "Ignored unknown ARP message: %a" Arpv4_packet.Unmarshal.pp_error e);
Lwt.return ()
| Ok arp ->
match Client_eth.ARP.input fixed_arp arp with
| None -> return ()
| Some response ->
iface#writev Ethif_wire.ARP [Arpv4_packet.Marshal.make_cstruct response]
(** Handle an IPv4 packet from the client. *)
let input_ipv4 ~client_ip ~router packet =
match Nat_packet.of_ipv4_packet packet with
| Error e ->
Log.warn (fun f -> f "Ignored unknown IPv4 message: %a" Nat_packet.pp_error e);
Lwt.return ()
| Ok packet ->
let `IPv4 (ip, _) = packet in
let src = ip.Ipv4_packet.src in
if src = client_ip then Firewall.ipv4_from_client router packet
else (
Log.warn (fun f -> f "Incorrect source IP %a in IP packet from %a (dropping)"
Ipaddr.V4.pp_hum src Ipaddr.V4.pp_hum client_ip);
return ()
)
(** Connect to a new client's interface and listen for incoming frames. *)
let add_vif { Dao.ClientVif.domid; device_id } ~client_ip ~router ~cleanup_tasks =
Netback.make ~domid ~device_id >>= fun backend ->
Log.info (fun f -> f "Client %d (IP: %s) ready" domid (Ipaddr.V4.to_string client_ip));
ClientEth.connect backend >>= fun eth ->
let client_mac = Netback.mac backend in
let client_eth = router.Router.client_eth in
let gateway_ip = Client_eth.client_gw client_eth in
let iface = new client_iface eth ~gateway_ip ~client_ip client_mac in
Router.add_client router iface >>= fun () ->
Cleanup.on_cleanup cleanup_tasks (fun () -> Router.remove_client router iface);
let fixed_arp = Client_eth.ARP.create ~net:client_eth iface in
Netback.listen backend (fun frame ->
match Ethif_packet.Unmarshal.of_cstruct frame with
| exception ex ->
Log.err (fun f -> f "Error unmarshalling ethernet frame from client: %s@.%a" (Printexc.to_string ex)
Cstruct.hexdump_pp frame
);
Lwt.return_unit
| Error err -> Log.warn (fun f -> f "Invalid Ethernet frame: %s" err); return ()
| Ok (eth, payload) ->
match eth.Ethif_packet.ethertype with
| Ethif_wire.ARP -> input_arp ~fixed_arp ~iface payload
| Ethif_wire.IPv4 -> input_ipv4 ~client_ip ~router payload
| Ethif_wire.IPv6 -> return ()
)
>|= or_raise "Listen on client interface" Netback.pp_error
(** A new client VM has been found in XenStore. Find its interface and connect to it. *)
let add_client ~router vif client_ip =
let cleanup_tasks = Cleanup.create () in
Log.info (fun f -> f "add client vif %a" Dao.ClientVif.pp vif);
Lwt.async (fun () ->
Lwt.catch (fun () ->
add_vif vif ~client_ip ~router ~cleanup_tasks
)
(fun ex ->
Log.warn (fun f -> f "Error with client %a: %s"
Dao.ClientVif.pp vif (Printexc.to_string ex));
return ()
)
);
cleanup_tasks
(** Watch XenStore for notifications of new clients. *)
let listen router =
Dao.watch_clients (fun new_set ->
(* Check for removed clients *)
!clients |> Dao.VifMap.iter (fun key cleanup ->
if not (Dao.VifMap.mem key new_set) then (
clients := !clients |> Dao.VifMap.remove key;
Log.info (fun f -> f "client %a has gone" Dao.ClientVif.pp key);
Cleanup.cleanup cleanup
)
);
(* Check for added clients *)
new_set |> Dao.VifMap.iter (fun key ip_addr ->
if not (Dao.VifMap.mem key !clients) then (
let cleanup = add_client ~router key ip_addr in
clients := !clients |> Dao.VifMap.add key cleanup
)
)
)