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# Copyright (c) 2011, 2012 Nicira, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at:
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""
ovsudp contains listener and sender classes for UDP protocol
"""
import array
import struct
import time
from twisted.internet.protocol import DatagramProtocol
from twisted.internet.task import LoopingCall
class UdpListener(DatagramProtocol):
"""
Class that will listen for incoming UDP packets
"""
def __init__(self):
self.stats = []
def datagramReceived(self, data, (_1, _2)):
"""This function is called each time datagram is received"""
try:
self.stats.append(struct.unpack_from("Q", data, 0))
except struct.error:
pass # ignore packets that are less than 8 bytes of size
def getResults(self):
"""Returns number of packets that were actually received"""
return len(self.stats)
class UdpSender(DatagramProtocol):
"""
Class that will send UDP packets to UDP Listener
"""
def __init__(self, host, count, size, duration):
# LoopingCall does not know whether UDP socket is actually writable
self.looper = None
self.host = host
self.count = count
self.duration = duration
self.start = time.time()
self.sent = 0
self.data = array.array('c', 'X' * size)
def startProtocol(self):
self.looper = LoopingCall(self.sendData)
period = self.duration / float(self.count)
self.looper.start(period , now = False)
def stopProtocol(self):
if (self.looper is not None):
self.looper.stop()
self.looper = None
def datagramReceived(self, data, (host, port)):
pass
def sendData(self):
"""This function is called from LoopingCall"""
if self.start + self.duration < time.time():
self.looper.stop()
self.looper = None
self.sent += 1
struct.pack_into('Q', self.data, 0, self.sent)
self.transport.write(self.data, self.host)
def getResults(self):
"""Returns number of packets that were sent"""
return self.sent
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