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|
;#!r6rs
;; This file is part of scheme-GNUnet, a partial Scheme port of GNUnet.
;; Copyright © 2021, 2022 GNUnet e.V.
;;
;; scheme-GNUnet is free software: you can redistribute it and/or modify it
;; under the terms of the GNU Affero General Public License as published
;; by the Free Software Foundation, either version 3 of the License,
;; or (at your option) any later version.
;;
;; scheme-GNUnet is distributed in the hope that it will be useful, but
;; WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
;; Affero General Public License for more details.
;;
;; You should have received a copy of the GNU Affero General Public License
;; along with this program. If not, see <http://www.gnu.org/licenses/>.
;;
;; SPDX-License-Identifier: AGPL-3.0-or-later
;; Brief: Interface to the network size estimation service.
;; C author: Nathan Evans
;; Scheme author: Maxime Devos
;;
;; The Scheme implementation is _not_ based on the C implementation,
;; though the Scheme API is structured after the C API and slightly
;; extended.
(define-library (gnu gnunet nse client)
(export estimate?
estimate:logarithmic-number-peers
estimate:number-peers
estimate:standard-deviation
estimate:timestamp
(rename (server:nse? server?))
connect
disconnect!
estimate)
(import (only (rnrs base)
begin define quote lambda values expt = apply
and >= let or nan?)
(only (rnrs records syntactic)
define-record-type)
(only (ice-9 atomic)
make-atomic-box atomic-box-ref atomic-box-set!)
(only (ice-9 match)
match)
(only (fibers)
spawn-fiber)
(only (gnu extractor enum)
symbol-value value->index)
(only (guile)
lambda* define*)
(only (gnu gnunet concurrency lost-and-found)
losable-lost-and-found)
(only (gnu gnunet util struct)
/:message-header)
(only (gnu gnunet utils bv-slice)
make-slice/read-write slice-length)
(only (gnu gnunet netstruct syntactic)
read% set%! sizeof)
(only (gnu gnunet mq handler)
message-handler
message-handlers)
(only (gnu gnunet mq)
send-message!)
(gnu gnunet message protocols)
(only (gnu gnunet server)
<server> make-disconnect!
handle-control-message!
<loop> spawn-server-loop run-loop loop:terminal-condition)
(only (gnu gnunet nse struct)
/:msg:nse:estimate))
(begin
(define-record-type (<estimate> %make-estimate estimate?)
(fields (immutable logarithmic-number-peers
%estimate:logarithmic-number-peers)
(immutable standard-deviation %estimate:standard-deviation)
(immutable timestamp %estimate:timestamp))
(sealed #t)
(opaque #t))
(define-record-type (<server:nse> %make-server server:nse?)
(parent <server>) ; for automatic fibers disposal when the <server> is unreachable
;; Atomic box of <estimate>
(fields (immutable estimate/box server-estimate/box))
(protocol
(lambda (%make)
(lambda ()
((%make) (make-atomic-box #false))))))
(define (estimate server)
"Return the current estimate of the number of peers on the network,
in some unspecified format. Alternatively, if no estimate is available
yet, return @code{#false}."
(atomic-box-ref (server-estimate/box server)))
(define (estimate:logarithmic-number-peers estimate)
"Return the logarithm (base 2) of the number of peers on the network
in @var{estimate} as a positive flonum (possibly zero or infinite)."
(%estimate:logarithmic-number-peers estimate))
(define (estimate:standard-deviation estimate)
"Return the standard deviation of the logarithmic estimate
of the number of peers of the last 64 rounds as a positive flonum
(possibly zero or infinite), or not-a-number."
(%estimate:standard-deviation estimate))
(define (estimate:number-peers estimate)
"Return the estimate of the number of peers on the network in
@var{estimate} as a strictly-positive flonum, at least @code{1.0}
and possibly infinite."
(expt 2.0 (estimate:logarithmic-number-peers estimate)))
(define (estimate:timestamp estimate)
"Return when the estimate @var{estimate} was made, as a standard GNUnet
timestamp."
(%estimate:timestamp estimate))
(define disconnect!
(make-disconnect! 'network-size server:nse?))
(define-record-type (<loop:nse> make-loop:nse loop:nse?)
(parent <loop>)
(fields (immutable updated loop:updated)
(immutable estimate/box loop:estimate/box))
(protocol
(lambda (%make)
(lambda* (#:key (updated values) estimate/box #:allow-other-keys
#:rest r)
((apply %make r) updated estimate/box)))))
;; See 'connect'. TODO: gc test fails
(define* (handle-estimate! estimate-slice estimate/box updated)
(define estimate
(%make-estimate
(read% /:msg:nse:estimate '(size-estimate) estimate-slice)
(read% /:msg:nse:estimate '(std-deviation) estimate-slice)
(read% /:msg:nse:estimate '(timestamp) estimate-slice)))
(atomic-box-set! estimate/box estimate)
(updated estimate))
(define (make-message-handlers loop)
(message-handlers
(message-handler
(type (symbol-value message-type msg:nse:estimate))
((interpose code) code)
((well-formed? slice)
(and (= (slice-length slice)
(sizeof /:msg:nse:estimate '()))
;; XXX: there is no test verifying these two expressions
;; are present
(>= (read% /:msg:nse:estimate '(size-estimate) slice) 0)
;; See <https://bugs.gnunet.org/view.php?id=7021#c18399> for
;; situations in which the deviation can be infinite or NaN.
(let ((stddev
(read% /:msg:nse:estimate '(std-deviation) slice)))
(or (>= stddev 0)
(nan? stddev)))))
((handle! slice) (handle-estimate! slice (loop:estimate/box loop)
(loop:updated loop))))))
(define (send-start! message-queue)
;; The service only starts sending estimates once
;; /:msg:nse:start is sent.
(define s (make-slice/read-write (sizeof /:message-header '())))
(set%! /:message-header '(size) s (sizeof /:message-header '()))
(set%! /:message-header '(type) s
(value->index (symbol-value message-type msg:nse:start)))
(send-message! message-queue s))
(define (control-message-handler message control control* message-queue loop)
(define (k/reconnect!)
(run-loop loop))
(match message
(('resend-old-operations!)
(send-start! message-queue)
(control loop)) ; continue
(('lost . _)
;; We lost ourselves, that means the server became unreachable.
;; The presence of this line is tested by the "garbage collectable"
;; test.
(control* '(disconnect!) loop))
(rest
(handle-control-message! message message-queue
(loop:terminal-condition loop) k/reconnect!))))
(define* (connect config #:key updated connected disconnected spawn
#:rest r)
"Connect to the NSE service in the background.
When connected, the thunk @var{connected} is called and estimates
will become available (but possibly not immediately). When a new
estimate is available, the procedure @var{updated} is called. This
procedure should accept the new estimate. When disconnected, the
thunk @code{disconnected} and updates will be (temporarily) unavailable,
until connected again. It is possible for @var{updated} to be called
shortly after calling @var{disconnected}.
The procedures @var{updated}, @var{connected} and @var{disconnected} are optional."
(define server (%make-server))
(apply spawn-server-loop server #:make-loop make-loop:nse
#:make-message-handlers make-message-handlers
#:control-message-handler control-message-handler
#:service-name "nse"
#:configuration config
#:estimate/box (server-estimate/box server) r))))
|
