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e70ccb91b1
build problems, and will give better diagnostics if not. Change-Id: I2f7a5d9b2e0c63a8189ad212125c7a5c0178c3c4 BUG=10567 TEST= Review URL: http://codereview.chromium.org/6331007
119 lines
3.6 KiB
Python
Executable File
119 lines
3.6 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 os
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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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try:
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SocketServer.TCPServer.__init__(self,
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('', port_in),
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self._Handler)
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except socket.error:
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os.system('sudo netstat -l --tcp -n -p')
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raise
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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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