syndicate-ssh/syndicate-ssh/new-server.rkt

209 lines
8.5 KiB
Racket

#lang syndicate
;;; SPDX-License-Identifier: LGPL-3.0-or-later
;;; SPDX-FileCopyrightText: Copyright © 2012-2021 Tony Garnock-Jones <tonyg@leastfixedpoint.com>
;;; (Temporary) example client and server
(require syndicate/drivers/timer)
(require syndicate/drivers/tcp)
(require syndicate/dataspace)
(require (only-in racket/port peek-bytes-avail!-evt))
(require "cook-port.rkt")
(require "sandboxes.rkt")
(require "ssh-numbers.rkt")
(require "ssh-transport.rkt")
(require "ssh-session.rkt")
(require "ssh-channel.rkt")
(require "ssh-message-types.rkt")
(require "ssh-exceptions.rkt")
(module+ main
(actor-system/dataspace (ds)
(spawn-timer-driver ds)
(spawn-tcp-driver ds)
(spawn #:name 'ssh-tcp-listener
(at ds
(during/spawn (Connection $conn (TcpLocal "0.0.0.0" 29418))
#:name (list 'ssh conn)
(session ds conn))))))
;;---------------------------------------------------------------------------
(define (check-remote-identification! peer-identification-string)
(define required-peer-identification-regex #rx"^SSH-2\\.0-.*")
;; Each identification string is both a cleartext indicator that
;; we've reached some notion of the right place and also input to
;; the hash function used during D-H key exchange.
(when (not (regexp-match required-peer-identification-regex
peer-identification-string))
(error 'ssh-session
"Invalid peer identification string ~v"
peer-identification-string)))
(define (session ground-ds conn)
(define local-identification #"SSH-2.0-RacketSSH_0.0")
(define id-line-reader-facet
(react
(on-start (send-line conn local-identification)
(send-lines-credit conn 1 (LineMode-crlf)))
(accept-connection conn
#:initial-credit #f
#:on-eof (lambda () (stop-current-facet))
#:on-data (lambda (remote-identification _mode)
(check-remote-identification! remote-identification)
(send! session-vm-factory remote-identification)))))
(define transfer-control
(object #:name 'transfer-control
[#:message 'transfer-control (stop-facet id-line-reader-facet)]))
(define session-vm-factory
(object
#:name 'session-vm-factory
[#:message remote-identification
(on-stop (log-info "Session VM for ~a closed" conn))
(actor-group
#:link? #t
(define conn-ds (dataspace #:name (gensym 'conn-ds)))
(spawn #:name 'reader (ssh-reader conn-ds conn transfer-control))
(spawn #:name 'writer (ssh-writer conn-ds conn))
;; Wait for the reader and writer get started, then tell the reader
;; we are ready for a single packet and spawn the session manager.
(react
(at conn-ds
(stop-when (asserted (Observe (:pattern (inbound-credit ,_)) _))
(send! conn-ds (inbound-credit 1))
(spawn
#:name 'session
(ssh-session conn-ds
ground-ds
local-identification
remote-identification
(lambda (user-name)
(error 'repl-boot "Would start session with ~a" user-name))
'server)))))
;; (at conn-ds
;; ;; (during $m
;; ;; (on-start (log-info "++ ~v" m))
;; ;; (on-stop (log-info "-- ~v" m)))
;; (when (message $m)
;; (log-info ">> ~v" m)))
(at conn-ds
(when (asserted (protocol-error $reason-code $message _ $originated-at-peer?))
(when (not originated-at-peer?)
(send! conn-ds
(outbound-packet (ssh-msg-disconnect reason-code
(string->bytes/utf-8 message)
#""))))
(sync! conn-ds (stop-actor-system)))))]))
(void))
;;---------------------------------------------------------------------------
;; ;; (repl-instance InputPort OutputPort InputPort OutputPort)
;; (struct repl-instance-state (c2s-in ;; used by thread to read input from relay
;; c2s-out ;; used by relay to feed input from remote to the thread
;; s2c-in ;; used by relay to feed output from thread to remote
;; s2c-out ;; used by thread to write output to relay
;; ) #:prefab)
;; (define (repl-instance user-name cname)
;; (define inbound-stream (channel-stream-name #t cname))
;; (define outbound-stream (channel-stream-name #f cname))
;; (define (ch-do action-ctor stream body)
;; (at-meta-level (action-ctor (channel-message stream body))))
;; (define (handle-channel-message state body)
;; (match body
;; [(channel-stream-request #"pty-req" _)
;; (match-define (repl-instance-state old-in _ _ old-out) state)
;; (define-values (cooked-in cooked-out) (cook-io old-in old-out "> "))
;; (transition (struct-copy repl-instance-state state
;; [c2s-in cooked-in]
;; [s2c-out cooked-out])
;; (ch-do send-feedback inbound-stream (channel-stream-ok)))]
;; [(channel-stream-notify #"env" _)
;; ;; Don't care
;; (transition state)]
;; [(channel-stream-request #"shell" _)
;; (match-define (repl-instance-state c2s-in _ s2c-in s2c-out) state)
;; (define buffer-size 1024)
;; (define dummy-buffer (make-bytes buffer-size))
;; (define repl-thread (thread (lambda () (repl-shell user-name c2s-in s2c-out))))
;; (transition state
;; (ch-do send-feedback inbound-stream (channel-stream-ok))
;; (subscriber (cons (thread-dead-evt repl-thread) (wild))
;; (on-message [_ (quit #f "REPL thread exited")]))
;; (subscriber (cons (peek-bytes-avail!-evt dummy-buffer 0 #f s2c-in) (wild))
;; ;; We're using peek-bytes-avail!-evt rather than
;; ;; read-bytes-avail!-evt because of potential overwriting
;; ;; of the buffer. The overwriting can happen when there's
;; ;; any latency between handling the event and the next
;; ;; firing of the event, since the peek-bytes-avail!-evt
;; ;; will overwrite its buffer next time it's synced on.
;; (match-state state
;; (on-message
;; [(cons _ (? eof-object?))
;; (let ()
;; (match-define (repl-instance-state c2s-in c2s-out s2c-in s2c-out) state)
;; (close-input-port c2s-in)
;; (close-output-port c2s-out)
;; (close-input-port s2c-in)
;; (close-output-port s2c-out)
;; (transition state (quit)))]
;; [(cons _ (? number? count))
;; (transition state
;; (ch-do send-message outbound-stream (channel-stream-data
;; (read-bytes count s2c-in))))]))))]
;; [(or (channel-stream-data #"\4") ;; C-d a.k.a EOT
;; (channel-stream-eof))
;; (let ()
;; (close-output-port (repl-instance-state-c2s-out state))
;; ;; ^ this signals the repl thread to exit.
;; ;; Now, wait for it to do so.
;; (transition state))]
;; [(channel-stream-data bs)
;; (write-bytes bs (repl-instance-state-c2s-out state))
;; (flush-output (repl-instance-state-c2s-out state))
;; (transition state
;; (ch-do send-feedback inbound-stream (channel-stream-credit (bytes-length bs))))]
;; [m
;; (write `(channel inbound ,m)) (newline)
;; (transition state)]))
;; (match (channel-name-type cname)
;; [#"session"
;; (define-values (c2s-in c2s-out) (make-pipe))
;; (define-values (s2c-in s2c-out) (make-pipe))
;; (transition (repl-instance-state c2s-in c2s-out s2c-in s2c-out)
;; (at-meta-level
;; (subscriber (channel-message inbound-stream (wild))
;; (match-state state
;; (on-presence (transition state
;; (ch-do send-feedback inbound-stream (channel-stream-config
;; (default-packet-limit)
;; #""))
;; (ch-do send-feedback inbound-stream (channel-stream-credit 1024))))
;; (on-message
;; [(channel-message _ body)
;; (handle-channel-message state body)]))))
;; (at-meta-level
;; (publisher (channel-message outbound-stream (wild))
;; (on-message [m (begin
;; (write `(channel outbound ,cname ,m)) (newline)
;; (void))]))))]
;; [type
;; (transition/no-state
;; (at-meta-level (send-message
;; (channel-message outbound-stream
;; (channel-stream-open-failure
;; SSH_OPEN_UNKNOWN_CHANNEL_TYPE
;; (bytes-append #"Unknown channel type " type))))))]))