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|
(*
* Copyright (c) 2012-2018 Vincent Bernardoff <vb@luminar.eu.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*
*)
open Astring
open Websocket
open Lwt.Infix
include Websocket.Make (Cohttp_lwt_unix.IO)
let section = Lwt_log.Section.make "websocket_lwt_unix"
exception HTTP_Error of string
let http_error msg = Lwt.fail (HTTP_Error msg)
let protocol_error msg = Lwt.fail (Protocol_error msg)
let set_tcp_nodelay flow =
let open Conduit_lwt_unix in
match flow with
| TCP { fd; _ } -> Lwt_unix.setsockopt fd Lwt_unix.TCP_NODELAY true
| _ -> ()
let fail_unless eq f = if not eq then f () else Lwt.return_unit
let fail_if eq f = if eq then f () else Lwt.return_unit
let drain_handshake req ic oc nonce =
Request.write (fun _writer -> Lwt.return ()) req oc >>= fun () ->
(Response.read ic >>= function
| `Ok r -> Lwt.return r
| `Eof -> Lwt.fail End_of_file
| `Invalid s -> Lwt.fail @@ Failure s)
>>= fun response ->
let open Cohttp in
let status = Response.status response in
let headers = Response.headers response in
fail_if
Code.(is_error @@ code_of_status status)
(fun () -> http_error Code.(string_of_status status))
>>= fun () ->
fail_unless
(Response.version response = `HTTP_1_1)
(fun () -> protocol_error "wrong http version")
>>= fun () ->
fail_unless (status = `Switching_protocols) (fun () ->
protocol_error "wrong status")
>>= fun () ->
(match Header.get headers "upgrade" with
| Some a when String.Ascii.lowercase a = "websocket" -> Lwt.return_unit
| _ -> protocol_error "wrong upgrade")
>>= fun () ->
fail_unless (upgrade_present headers) (fun () ->
protocol_error "upgrade header not present")
>>= fun () ->
match Header.get headers "sec-websocket-accept" with
| Some accept when accept = b64_encoded_sha1sum (nonce ^ websocket_uuid) ->
Lwt.return_unit
| _ -> protocol_error "wrong accept"
let connect ctx client url nonce extra_headers =
let open Cohttp in
let headers =
Header.add_list extra_headers
[
("Upgrade", "websocket");
("Connection", "Upgrade");
("Sec-WebSocket-Key", nonce);
("Sec-WebSocket-Version", "13");
]
in
let req = Request.make ~headers url in
Conduit_lwt_unix.connect ~ctx client >>= fun (flow, ic, oc) ->
set_tcp_nodelay flow;
Lwt.catch
(fun () -> drain_handshake req ic oc nonce)
(fun exn -> Lwt_io.close ic >>= fun () -> Lwt.fail exn)
>>= fun () ->
Lwt_log.info_f ~section "Connected to %s" (Uri.to_string url) >>= fun () ->
Lwt.return (ic, oc)
type conn = {
read_frame : unit -> Frame.t Lwt.t;
write_frame : Websocket.Frame.t -> unit Lwt.t;
oc : Lwt_io.output_channel;
}
let read { read_frame; _ } = read_frame ()
let write { write_frame; _ } frame = write_frame frame
let close_transport { oc; _ } = Lwt_io.close oc
let connect ?(extra_headers = Cohttp.Header.init ())
?(random_string = Websocket.Rng.init ())
?(ctx = Lazy.force Conduit_lwt_unix.default_ctx) ?buf client url =
let nonce = Base64.encode_exn (random_string 16) in
connect ctx client url nonce extra_headers >|= fun (ic, oc) ->
let read_frame = make_read_frame ?buf ~mode:(Client random_string) ic oc in
let read_frame () =
Lwt.catch read_frame (fun exn ->
Lwt.async (fun () -> Lwt_io.close ic);
Lwt.fail exn)
in
let buf = Buffer.create 128 in
let write_frame frame =
Buffer.clear buf;
Lwt.wrap2 (write_frame_to_buf ~mode:(Client random_string)) buf frame
>>= fun () ->
Lwt.catch
(fun () ->
Lwt_io.write oc (Buffer.contents buf) >>= fun () -> Lwt_io.flush oc)
(fun exn ->
Lwt.async (fun () -> Lwt_io.close oc);
Lwt.fail exn)
in
{ read_frame; write_frame; oc }
let write_failed_response oc =
let body = "403 Forbidden" in
let body_len = String.length body |> Int64.of_int in
let response =
Cohttp.Response.make ~status:`Forbidden
~encoding:(Cohttp.Transfer.Fixed body_len) ()
in
let open Response in
write ~flush:true (fun writer -> write_body writer body) response oc
let server_fun ?read_buf ?write_buf check_request flow ic oc react =
let read = function
| `Ok r -> Lwt.return r
| `Eof ->
(* Remote endpoint closed connection. No further action necessary here. *)
Lwt_log.info ~section "Remote endpoint closed connection" >>= fun () ->
Lwt.fail End_of_file
| `Invalid reason ->
Lwt_log.info_f ~section "Invalid input from remote endpoint: %s" reason
>>= fun () -> Lwt.fail @@ HTTP_Error reason
in
Request.read ic >>= read >>= fun request ->
let meth = Cohttp.Request.meth request in
let version = Cohttp.Request.version request in
let headers = Cohttp.Request.headers request in
let key = Cohttp.Header.get headers "sec-websocket-key" in
(match
( version,
meth,
Cohttp.Header.get headers "upgrade",
key,
upgrade_present headers,
check_request request )
with
| `HTTP_1_1, `GET, Some up, Some key, true, true
when String.Ascii.lowercase up = "websocket" ->
Lwt.return key
| _ ->
write_failed_response oc >>= fun () ->
Lwt.fail (Protocol_error "Bad headers"))
>>= fun key ->
let hash = key ^ websocket_uuid |> b64_encoded_sha1sum in
let response_headers =
Cohttp.Header.of_list
[
("Upgrade", "websocket");
("Connection", "Upgrade");
("Sec-WebSocket-Accept", hash);
]
in
let response =
Cohttp.Response.make ~status:`Switching_protocols
~encoding:Cohttp.Transfer.Unknown ~headers:response_headers ()
in
Response.write (fun _writer -> Lwt.return_unit) response oc >>= fun () ->
let client =
Connected_client.create ?read_buf ?write_buf request flow ic oc
in
react client
let establish_server ?read_buf ?write_buf ?timeout ?stop
?(on_exn = fun exn -> !Lwt.async_exception_hook exn)
?(check_request = check_origin_with_host)
?(ctx = Lazy.force Conduit_lwt_unix.default_ctx) ~mode react =
let module C = Cohttp in
Conduit_lwt_unix.serve ~on_exn ?timeout ?stop ~ctx ~mode (fun flow ic oc ->
set_tcp_nodelay flow;
Lwt.catch
(fun () ->
server_fun ?read_buf ?write_buf check_request
(Conduit_lwt_unix.endp_of_flow flow)
ic oc react)
(function
| End_of_file -> Lwt.return_unit
| HTTP_Error _ -> Lwt.return_unit
| exn -> Lwt.fail exn))
let mk_frame_stream recv =
let f () =
recv () >>= fun fr ->
match fr.Frame.opcode with
| Frame.Opcode.Close -> Lwt.return_none
| _ -> Lwt.return (Some fr)
in
Lwt_stream.from f
let establish_standard_server ?read_buf ?write_buf ?timeout ?stop ?on_exn
?check_request ?(ctx = Lazy.force Conduit_lwt_unix.default_ctx) ~mode react
=
let f client = react (Connected_client.make_standard client) in
establish_server ?read_buf ?write_buf ?timeout ?stop ?on_exn ?check_request
~ctx ~mode f
|
