83 lines
2.4 KiB
Racket
83 lines
2.4 KiB
Racket
#lang racket/base
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;; UDP drivers for os.rkt
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(require racket/match)
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(require racket/udp)
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(require "dump-bytes.rkt")
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(require "os-userland-stdlib.rkt")
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(provide (struct-out udp-address)
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(struct-out udp-packet)
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udp-driver
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udp-spy)
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;; A UdpAddress is one of
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;; -- a (udp-address String Uint16), representing a remote socket
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;; -- a (udp-address #f Uint16), representing a local socket
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(struct udp-address (host port) #:prefab)
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;; A UdpPacket is a (udp-packet UdpAddress UdpAddress Bytes), and
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;; represents a packet appearing on our local "subnet" of the full UDP
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;; network, complete with source, destination and contents.
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(struct udp-packet (source destination body) #:prefab)
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;; TODO: BUG?: Routing packets between two local sockets won't work
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;; because the patterns aren't set up to recognise that situation.
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(define udp-driver
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(userland
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(lambda ()
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(rpc-service
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[`(udp new ,port-number ,buffer-size)
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(define s (udp-open-socket #f #f))
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(when port-number
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(udp-bind! s #f port-number))
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(define-values (_local-address local-port _remote-address _remote-port)
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(udp-addresses s #t))
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(define sname (udp-address #f local-port))
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(spawn (userland (udp-sender sname s)))
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(spawn (userland (udp-receiver sname s buffer-size)))
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(spawn (userland (udp-closer sname s)))
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sname]))))
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(define ((udp-sender sname s))
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(let loop ()
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(wait (message-handlers
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[`(close ,(== sname))
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(void)]
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[(udp-packet (== sname) (udp-address host port) body)
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(meta-send (lambda () (udp-send-to s host port body)))
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(loop)]))))
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(define ((udp-receiver sname s buffer-size))
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(define buffer (make-bytes buffer-size))
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(let loop ()
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(wait (message-handlers
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[`(close ,(== sname))
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(void)])
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(meta-message-handlers
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[((list 'udp-receive sname)
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(udp-receive!-evt s buffer)
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=> (list packet-length host port))
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(define packet (subbytes buffer 0 packet-length))
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(send (udp-packet (udp-address host port) sname packet))
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(loop)]))))
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(define ((udp-closer sname s))
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(wait (message-handlers
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[`(close ,(== sname))
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(udp-close s)])))
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(define udp-spy
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(userland
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(lambda ()
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(let loop ()
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(wait (message-handlers
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[(udp-packet source dest body)
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(write `(UDP ,source --> ,dest)) (newline)
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(dump-bytes! body (bytes-length body))]
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[x
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(write `(UDP ,x)) (newline)]))
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(loop)))))
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