albatross/tls/vmm_tls_lwt.ml

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2018-10-23 22:10:08 +00:00
(* (c) 2017 Hannes Mehnert, all rights reserved *)
open Lwt.Infix
let read_tls t =
let rec r_n buf off tot =
let l = tot - off in
if l = 0 then
Lwt.return (Ok ())
else
Tls_lwt.Unix.read t (Cstruct.shift buf off) >>= function
| 0 ->
Logs.debug (fun m -> m "TLS: end of file") ;
Lwt.return (Error `Eof)
| x when x == l -> Lwt.return (Ok ())
| x when x < l -> r_n buf (off + x) tot
| _ ->
Logs.err (fun m -> m "TLS: read too much, shouldn't happen") ;
Lwt.return (Error `Toomuch)
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in
let buf = Cstruct.create 4 in
r_n buf 0 4 >>= function
| Error e -> Lwt.return (Error e)
| Ok () ->
let len = Cstruct.BE.get_uint32 buf 0 in
if len > 0l then
let b = Cstruct.create (Int32.to_int len) in
r_n b 0 (Int32.to_int len) >|= function
| Error e -> Error e
| Ok () ->
(* Logs.debug (fun m -> m "TLS read id %d %a tag %d data %a"
hdr.Vmm_wire.id Vmm_wire.pp_version hdr.Vmm_wire.version hdr.Vmm_wire.tag
Cstruct.hexdump_pp b) ; *)
match Vmm_asn.wire_of_cstruct b with
| Error (`Msg msg) ->
Logs.err (fun m -> m "error %s while parsing data" msg) ;
Error `Exception
| (Ok (hdr, _)) as w ->
if not Vmm_commands.(is_current hdr.version) then
Logs.warn (fun m -> m "version mismatch, received %a current %a"
Vmm_commands.pp_version hdr.Vmm_commands.version
Vmm_commands.pp_version Vmm_commands.current);
w
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else
Lwt.return (Error `Eof)
let write_tls s wire =
let data = Vmm_asn.wire_to_cstruct wire in
let dlen = Cstruct.create 4 in
Cstruct.BE.set_uint32 dlen 0 (Int32.of_int (Cstruct.len data)) ;
let buf = Cstruct.(append dlen data) in
(* Logs.debug (fun m -> m "TLS write %a" Cstruct.hexdump_pp (Cstruct.of_string buf)) ; *)
Lwt.catch
(fun () -> Tls_lwt.Unix.write s buf >|= fun () -> Ok ())
(function
| Tls_lwt.Tls_failure a ->
Logs.err (fun m -> m "tls failure: %s" (Tls.Engine.string_of_failure a)) ;
Lwt.return (Error `Exception)
| e ->
Logs.err (fun m -> m "TLS write exception %s" (Printexc.to_string e)) ;
Lwt.return (Error `Exception))
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let close tls =
Lwt.catch
(fun () -> Tls_lwt.Unix.close tls)
(fun _ -> Lwt.return_unit)