eac58982d9
implement RFC-005 - server broadcasts once on startup and answers to broadcasts - small tool for listening on the port and sending broadcasts Change-Id: I02d1184d6be62bef6f964eb9d238220aef062e94 Reviewed-on: https://forge.frm2.tum.de/review/c/secop/frappy/+/34851 Tested-by: Jenkins Automated Tests <pedersen+jenkins@frm2.tum.de> Reviewed-by: Georg Brandl <g.brandl@fz-juelich.de>
129 lines
4.0 KiB
Python
Executable File
129 lines
4.0 KiB
Python
Executable File
#!/usr/bin/env python3
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# *****************************************************************************
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#
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# This program is free software; you can redistribute it and/or modify it under
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# the terms of the GNU General Public License as published by the Free Software
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# Foundation; either version 2 of the License, or (at your option) any later
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# version.
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#
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# This program is distributed in the hope that it will be useful, but WITHOUT
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# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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# FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
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# details.
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#
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# You should have received a copy of the GNU General Public License along with
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# this program; if not, write to the Free Software Foundation, Inc.,
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# 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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#
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# Module authors:
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# Alexander Zaft <a.zaft@fz-juelich.de>
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#
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# *****************************************************************************
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"""SEC node autodiscovery tool."""
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import argparse
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import json
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import os
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import select
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import socket
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import sys
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from collections import namedtuple
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from time import time as currenttime
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UDP_PORT = 10767
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Answer = namedtuple('Answer',
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'address, port, equipment_id, firmware, description')
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def decode(msg, addr):
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msg = msg.decode('utf-8')
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try:
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data = json.loads(msg)
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except Exception:
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return None
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if not isinstance(data, dict):
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return None
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if data.get('SECoP') != 'node':
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return None
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try:
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eq_id = data['equipment_id']
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fw = data['firmware']
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desc = data['description']
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port = data['port']
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except KeyError:
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return None
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addr, _scanport = addr
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return Answer(addr, port, eq_id, fw, desc)
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def print_answer(answer, *, short=False):
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if short:
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# NOTE: keep this easily parseable!
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print(f'{answer.equipment_id} {answer.address}:{answer.port}')
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return
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print(f'Found {answer.equipment_id} at {answer.address}:')
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print(f' Port: {answer.port}')
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print(f' Firmware: {answer.firmware}')
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desc = answer.description.replace('\n', '\n ')
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print(f' Node description: {desc}')
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print()
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def scan(max_wait=1.0):
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s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
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s.setsockopt(socket.SOL_SOCKET, socket.SO_BROADCAST, 1)
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# send a general broadcast
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try:
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s.sendto(json.dumps(dict(SECoP='discover')).encode('utf-8'),
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('255.255.255.255', UDP_PORT))
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except OSError as e:
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print('could not send the broadcast:', e)
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# we still keep listening for self-announcements
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start = currenttime()
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seen = set()
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while currenttime() < start + max_wait:
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res = select.select([s], [], [], 0.1)
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if res[0]:
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try:
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msg, addr = s.recvfrom(1024)
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except socket.error: # pragma: no cover
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continue
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answer = decode(msg, addr)
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if answer is None:
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continue
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if (answer.address, answer.equipment_id, answer.port) in seen:
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continue
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seen.add((answer.address, answer.equipment_id, answer.port))
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yield answer
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def listen(*, short=False):
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s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
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if os.name == 'nt':
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s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
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else:
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s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEPORT, 1)
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s.bind(('0.0.0.0', UDP_PORT))
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while True:
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try:
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msg, addr = s.recvfrom(1024)
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except KeyboardInterrupt:
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break
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answer = decode(msg, addr)
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if answer:
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print_answer(answer, short=short)
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if __name__ == '__main__':
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parser = argparse.ArgumentParser()
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parser.add_argument('-l', '--listen', action='store_true',
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help='Print short info. '
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'Keep listening after the broadcast.')
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args = parser.parse_args(sys.argv[1:])
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for answer in scan():
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print_answer(answer, short=args.listen)
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if args.listen:
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listen(short=args.listen)
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