76 lines
2.8 KiB
Racket
76 lines
2.8 KiB
Racket
#lang racket/base
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;; DNS drivers using marketplace.
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;;
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;;; Copyright 2010, 2011, 2012, 2013 Tony Garnock-Jones <tonyg@ccs.neu.edu>
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;;;
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;;; This file is part of marketplace-dns.
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;;;
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;;; marketplace-dns is free software: you can redistribute it and/or
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;;; modify it under the terms of the GNU General Public License as
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;;; published by the Free Software Foundation, either version 3 of the
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;;; License, or (at your option) any later version.
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;;;
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;;; marketplace-dns is distributed in the hope that it will be useful,
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;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
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;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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;;; General Public License for more details.
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;;;
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;;; You should have received a copy of the GNU General Public License
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;;; along with marketplace-dns. If not, see
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;;; <http://www.gnu.org/licenses/>.
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(require racket/set)
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(require racket/match)
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(require "codec.rkt")
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(require syndicate/actor)
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(require syndicate/drivers/udp)
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(provide (struct-out bad-dns-packet)
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(struct-out dns-request)
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(struct-out dns-reply)
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dns-read-driver
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dns-write-driver
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dns-spy)
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(struct bad-dns-packet (detail source sink reason) #:transparent)
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(struct dns-request (message source sink) #:transparent)
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(struct dns-reply (message source sink) #:transparent)
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(define (dns-read-driver s)
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(actor
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(forever
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(on (message (udp-packet $source s #"") #:meta-level 1)
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(log-info "Debug dump packet received")
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(send! `(debug-dump)))
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(on (message (udp-packet $source s $body) #:meta-level 1)
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(send!
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(with-handlers ((exn:fail? (lambda (e)
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(bad-dns-packet body source s 'unparseable))))
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(define message (packet->dns-message body))
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(case (dns-message-direction message)
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((request) (dns-request message source s))
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((response) (dns-reply message source s)))))))))
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(define (translate message s sink)
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(with-handlers ((exn:fail? (lambda (e)
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(send! (bad-dns-packet message s sink 'unencodable)))))
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(send! #:meta-level 1 (udp-packet s sink (dns-message->packet message)))))
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(define (dns-write-driver s)
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(actor (forever
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(on (message (dns-request $message s $sink))
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(translate message s sink))
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(on (message (dns-reply $message s $sink))
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(translate message s sink)))))
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(define (dns-spy)
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(actor (forever
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(on (message (dns-request $message $source $sink))
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(log-info (format "DNS: ~v asks ~v ~v~n : ~v"
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source sink (dns-message-id message)
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(dns-message-questions message))))
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(on (message (dns-reply $message $source $sink))
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(log-info (format "DNS: ~v answers ~v~n : ~v"
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source sink
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message))))))
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