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racket-ssh-2012
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Extract identification string before switching to packet mode

This commit is contained in:
Tony Garnock-Jones 2012-06-11 12:33:32 -04:00
parent e2e59bdf6c
commit 72acd94def
2 changed files with 67 additions and 38 deletions
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39
new-server.rkt
View File

@ -13,20 +13,47 @@
(define server-addr (tcp-listener 2322)) (define server-addr (tcp-listener 2322))
(define (connection-handler local-addr remote-addr) (define (connection-handler local-addr remote-addr)
(define local-identification #"SSH-2.0-RacketSSH_0.0")
(nested-vm (nested-vm
(list 'ssh-session-vm remote-addr) (list 'ssh-session-vm remote-addr)
(lambda (nested-boot-pid)
(transition 'running (transition 'running
;; Issue identification string.
(at-meta-level (at-meta-level
(send-message (tcp-channel local-addr remote-addr #"SSH-2.0-RacketSSH_0.0\r\n"))) (send-message (tcp-channel local-addr
remote-addr
(bytes-append local-identification #"\r\n"))))
;; Expect identification string, then update (!) our inbound
;; subscription handler to switch to packet mode.
(at-meta-level (send-tcp-mode remote-addr local-addr 'lines)) (at-meta-level (send-tcp-mode remote-addr local-addr 'lines))
(at-meta-level (send-tcp-credit remote-addr local-addr 1)) (at-meta-level (send-tcp-credit remote-addr local-addr 1))
(at-meta-level
(role 'identification-handler (topic-subscriber %%%
(spawn (ssh-reader local-addr remote-addr) #:debug-name 'ssh-reader) (spawn
(transition 'handshake-is-stateless
(at-meta-level
(role 'socket-reader (topic-subscriber (tcp-channel remote-addr local-addr (wild)))
#:state state
[(tcp-channel _ _ (? eof-object?))
(transition state (kill))]
[(tcp-channel _ _ (? bytes? remote-identification))
;; First, set the incoming mode to bytes. Then
;; initialise the reader, switching to packet-reading
;; mode. Finally, spawn the remaining processes and
;; issue the initial credit to the reader.
(extend-transition
(prefix-transition (ssh-reader local-addr remote-addr)
(at-meta-level (send-tcp-mode remote-addr local-addr 'bytes)))
(spawn (ssh-writer local-addr remote-addr) #:debug-name 'ssh-writer) (spawn (ssh-writer local-addr remote-addr) #:debug-name 'ssh-writer)
;; Wait for a cycle to let the reader and writer get
;; started, then tell the reader we are ready for a
;; single packet.
(yield #:state state (yield #:state state
(transition state (send-message (inbound-credit 1)))) (transition state (send-message (inbound-credit 1)))))])))
#:debug-name 'ssh-reader)
(role 'crash-listener (role 'crash-listener
(set (topic-subscriber (wild) #:virtual? #t) (set (topic-subscriber (wild) #:virtual? #t)
(topic-publisher (wild) #:virtual? #t)) (topic-publisher (wild) #:virtual? #t))
@ -53,7 +80,7 @@
(write (list 'SSH msg)) (write (list 'SSH msg))
(newline) (newline)
(flush-output) (flush-output)
state])))) state])))))
(ground-vm (ground-vm
(transition 'no-state (transition 'no-state

2
ssh-transport.rkt
View File

@ -300,6 +300,8 @@
hmac-description) hmac-description)
sequence-number sequence-number
remaining-credit)) remaining-credit))
[(tcp-channel _ _ (? eof-object?))
(transition state (kill))]
[(tcp-channel _ _ (? bytes? encrypted-packet)) [(tcp-channel _ _ (? bytes? encrypted-packet))
(define block-size (supported-cipher-block-size cipher-description)) (define block-size (supported-cipher-block-size cipher-description))
(define first-block-size block-size) (define first-block-size block-size)