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ability to filter or manipulate content as it's passed through. Create two example tests using this utility that cause updates to close early to test resumes, and to add delays to make sure the update still completes correctly. What other tests should be created for this? BUG=chromium-os:8207 TEST=Run by hand Review URL: http://codereview.chromium.org/5632002 Change-Id: Iefb8c8e223fb2ba6bad2c551f7c4403a0bec6ecf
114 lines
3.5 KiB
Python
Executable File
114 lines
3.5 KiB
Python
Executable File
# Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
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# Use of this source code is governed by a BSD-style license that can be
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# found in the LICENSE file.
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import select
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import socket
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import SocketServer
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import threading
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class Filter(object):
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"""Base class for data filters.
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Pass subclass of this to CrosTestProxy which will perform whatever
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connection manipulation you prefer.
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"""
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def setup(self):
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"""This setup method is called once per connection."""
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pass
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def InBound(self, data):
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"""This method is called once per packet of incoming data.
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The value returned is what is sent through the proxy. If
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None is returned, the connection will be closed.
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"""
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return data
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def OutBound(self, data):
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"""This method is called once per packet of outgoing data.
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The value returned is what is sent through the proxy. If
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None is returned, the connection will be closed.
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"""
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return data
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class CrosTestProxy(SocketServer.ThreadingMixIn, SocketServer.TCPServer):
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"""A transparent proxy for simulating network errors"""
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class _Handler(SocketServer.BaseRequestHandler):
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"""Proxy connection handler that passes data though a filter"""
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def setup(self):
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"""Setup is called once for each connection proxied."""
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self.server.filter.setup()
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def handle(self):
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"""Handles each incoming connection.
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Opens a new connection to the port we are proxing to, then
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passes each packet along in both directions after passing
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them through the filter object passed in.
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"""
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# Open outgoing socket
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s_in = self.request
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s_out = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
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s_out.connect((self.server.address_out, self.server.port_out))
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while True:
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rlist, wlist, xlist = select.select([s_in, s_out], [], [])
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if s_in in rlist:
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data = s_in.recv(1024)
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data = self.server.filter.InBound(data)
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if not data: break
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try:
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# If there is any error sending data, close both connections.
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s_out.sendall(data)
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except socket.error:
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break
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if s_out in rlist:
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data = s_out.recv(1024)
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data = self.server.filter.OutBound(data)
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if not data: break
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try:
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# If there is any error sending data, close both connections.
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s_in.sendall(data)
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except socket.error:
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break
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s_in.close()
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s_out.close()
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def __init__(self,
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filter,
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port_in=8081,
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address_out='127.0.0.1', port_out=8080):
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"""Configures the proxy object.
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Args:
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filter: An instance of a subclass of Filter.
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port_in: Port on which to listen for incoming connections.
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address_out: Address to which outgoing connections will go.
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address_port: Port to which outgoing connections will go.
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"""
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self.port_in = port_in
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self.address_out = address_out
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self.port_out = port_out
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self.filter = filter
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SocketServer.TCPServer.__init__(self,
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('', port_in),
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self._Handler)
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def serve_forever_in_thread(self):
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"""Helper method to start the server in a new background thread."""
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server_thread = threading.Thread(target=self.serve_forever)
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server_thread.setDaemon(True)
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server_thread.start()
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return server_thread
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