/
pscsim.py
executable file
·141 lines (109 loc) · 4.34 KB
/
pscsim.py
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#!/usr/bin/env python3
import logging
import time
import struct
import signal
import asyncio
_log = logging.getLogger(__name__)
def getargs():
from argparse import ArgumentParser
P = ArgumentParser()
P.add_argument('endpoint', help='Bind to address:port')
P.add_argument('-v', '--verbose', action='store_const',
const=logging.DEBUG, default=logging.INFO,
help='Make some noise')
P.add_argument('-U', '--udp', action='store_true')
P.add_argument('-T', '--tcp', action='store_false', dest='udp')
return P
def build_msg(msgid, body):
blen = len(body)
return struct.pack('>2sHI', b'PS', msgid, blen) + body
async def tcp_keepalive(writer):
peer = writer.get_extra_info('peername')
while True:
_log.debug('%s ping', peer)
writer.write(build_msg(42, b"hello world!"))
await writer.drain()
await asyncio.sleep(1.0)
async def handle_tcp_client(reader, writer):
loop = asyncio.get_running_loop()
peer = writer.get_extra_info('peername')
_log.info('New client %s', peer)
pinger = loop.create_task(tcp_keepalive(writer))
try:
writer.write(build_msg(100, b'\x00\x00\x124\x00\x00\x00*'))
writer.write(build_msg(100, b'\x00\x00\x12>\x00\x00\x00+'))
await writer.drain()
while True:
P, S, msgid, blen = struct.unpack('>ccHI', await reader.readexactly(8))
_log.debug('RX %s msgid %d blen %d', peer, msgid, blen)
if P!=b'P' or S!=b'S':
raise RuntimeError('Framing error')
body = await reader.readexactly(blen)
# Echo back with a different ID (ID+10)
if msgid>=1000:
# Echo back with a different ID w/ timestamp prepended
SEC, NS = divmod(time.time(), 1.0)
body = struct.pack('>II', int(SEC), int(NS*1e9)) + body
msgid += 10
writer.write(build_msg(msgid, body))
await writer.drain()
except asyncio.IncompleteReadError:
pass # normal on close
except:
_log.exception('Error client %s', peer)
finally:
pinger.cancel()
try:
await pinger
except asyncio.CancelledError:
pass
_log.info('Lost client %s', peer)
class UDPProto(object):
def connection_made(self, transport):
self.transport = transport
self.peer = None
_log.info('Listening on %s', transport.get_extra_info('sockname'))
def datagram_received(self, data, addr):
P, S, msgid, blen = struct.unpack('>ccHI', data[:8])
_log.debug('RX %s msgid %d blen %d', addr, msgid, blen)
if P!=b'P' or S!=b'S':
_log.error('Ignore invalid RX %s msgid %d blen %d', addr, msgid, blen)
return
body = data[8:8+blen]
if addr != self.peer:
_log.info('New peer %s -> %s', self.peer, addr)
self.peer = addr
self.transport.sendto(build_msg(100, b'\x00\x00\x124\x00\x00\x00*'), addr)
self.transport.sendto(build_msg(100, b'\x00\x00\x12>\x00\x00\x00+'), addr)
# Echo back with a different ID (ID+10)
if msgid>=1000:
# Echo back with a different ID w/ timestamp prepended
SEC, NS = divmod(time.time(), 1.0)
body = struct.pack('>II', int(SEC), int(NS*1e9)) + body
msgid += 10
self.transport.sendto(build_msg(msgid, body), addr)
async def main(args):
loop = asyncio.get_running_loop()
logging.basicConfig(level=args.verbose)
host, _sep, port = args.endpoint.partition(':')
port = int(port or '1234')
_log.info('Binding to %s:%s', host, port)
if args.udp:
sock, proto = await loop.create_datagram_endpoint(lambda: UDPProto(), local_addr=(host, port))
else:
sock = await asyncio.start_server(handle_tcp_client, host=host, port=port)
done = asyncio.Event()
loop.add_signal_handler(signal.SIGINT, done.set)
_log.info('Running')
await done.wait()
_log.info('Done')
if __name__=='__main__':
if not hasattr(asyncio, 'run'):
def run(coro):
loop = asyncio.get_event_loop()
loop.run_until_complete(coro)
asyncio.run = run
# we only use one loop, so this is equivalent
asyncio.get_running_loop = asyncio.get_event_loop
asyncio.run(main(getargs().parse_args()))