1# Copyright (c) 2012 The Chromium OS Authors. All rights reserved.
2# Use of this source code is governed by a BSD-style license that can be
3# found in the LICENSE file.
4
5import logging
6import socket
7import time
8import urllib2
9
10import common
11
12from autotest_lib.client.common_lib import error
13from autotest_lib.client.cros import routing
14
15
16def CheckInterfaceForDestination(host, expected_interface):
17    """
18    Checks that routes for host go through a given interface.
19
20    The concern here is that our network setup may have gone wrong
21    and our test connections may go over some other network than
22    the one we're trying to test.  So we take all the IP addresses
23    for the supplied host and make sure they go through the given
24    network interface.
25
26    @param host: Destination host
27    @param expected_interface: Expected interface name
28    @raises: error.TestFail if the routes for the given host go through
29            a different interface than the expected one.
30
31    """
32    # addrinfo records: (family, type, proto, canonname, (addr, port))
33    server_addresses = [record[4][0]
34                        for record in socket.getaddrinfo(host, 80)]
35
36    route_found = False
37    routes = routing.NetworkRoutes()
38    for address in server_addresses:
39        route = routes.getRouteFor(address)
40        if not route:
41            continue
42
43        route_found = True
44
45        interface = route.interface
46        logging.info('interface for %s: %s', address, interface)
47        if interface != expected_interface:
48            raise error.TestFail('Target server %s uses interface %s'
49                                 '(%s expected).' %
50                                 (address, interface, expected_interface))
51
52    if not route_found:
53        raise error.TestFail('No route found for "%s".' % host)
54
55FETCH_URL_PATTERN_FOR_TEST = \
56    'http://testing-chargen.appspot.com/download?size=%d'
57
58def FetchUrl(url_pattern, bytes_to_fetch=10, fetch_timeout=10):
59    """
60    Fetches a specified number of bytes from a URL.
61
62    @param url_pattern: URL pattern for fetching a specified number of bytes.
63            %d in the pattern is to be filled in with the number of bytes to
64            fetch.
65    @param bytes_to_fetch: Number of bytes to fetch.
66    @param fetch_timeout: Number of seconds to wait for the fetch to complete
67            before it times out.
68    @return: The time in seconds spent for fetching the specified number of
69            bytes.
70    @raises: error.TestError if one of the following happens:
71            - The fetch takes no time.
72            - The number of bytes fetched differs from the specified
73              number.
74
75    """
76    # Limit the amount of bytes to read at a time.
77    _MAX_FETCH_READ_BYTES = 1024 * 1024
78
79    url = url_pattern % bytes_to_fetch
80    logging.info('FetchUrl %s', url)
81    start_time = time.time()
82    result = urllib2.urlopen(url, timeout=fetch_timeout)
83    bytes_fetched = 0
84    while bytes_fetched < bytes_to_fetch:
85        bytes_left = bytes_to_fetch - bytes_fetched
86        bytes_to_read = min(bytes_left, _MAX_FETCH_READ_BYTES)
87        bytes_read = len(result.read(bytes_to_read))
88        bytes_fetched += bytes_read
89        if bytes_read != bytes_to_read:
90            raise error.TestError('FetchUrl tried to read %d bytes, but got '
91                                  '%d bytes instead.' %
92                                  (bytes_to_read, bytes_read))
93        fetch_time = time.time() - start_time
94        if fetch_time > fetch_timeout:
95            raise error.TestError('FetchUrl exceeded timeout.')
96
97    return fetch_time
98