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      1 # Copyright 2014 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 
      5 import logging
      6 import socket
      7 
      8 from autotest_lib.client.common_lib import error
      9 
     10 
     11 # See server/cros/network/wifi_test_context_manager.py for commandline
     12 # flags to control IP addresses in WiFi tests.
     13 DEFAULT_FAILURE_MESSAGE = (
     14         'Cannot infer DNS name of companion device from an IP address.')
     15 ATTENUATOR_FAILURE_MESSAGE = (
     16         'Cannot infer DNS name of WiFi variable attenuator from a client IP '
     17         'address.  Use --atten_addr=<ip or dns name>')
     18 BLUETOOTH_TESTER_FAILURE_MESSAGE = (
     19         'Remote host cannot be an IP address unless tester specified with '
     20          '--args tester=IP')
     21 ROUTER_FAILURE_MESSAGE = (
     22         'Cannot infer DNS name of WiFi router from a client IP address.')
     23 
     24 
     25 def is_ip_address(hostname):
     26     """Infers whether |hostname| could be an IP address.
     27 
     28     @param hostname: string DNS name or IP address.
     29     @return True iff hostname is a valid IP address.
     30 
     31     """
     32     try:
     33         socket.inet_aton(hostname)
     34         return True
     35     except socket.error:
     36         return False
     37 
     38 
     39 def get_companion_device_addr(client_hostname,
     40                               suffix,
     41                               cmdline_override=None,
     42                               not_dnsname_msg=DEFAULT_FAILURE_MESSAGE,
     43                               allow_failure=False):
     44     """Build a usable hostname for a test companion device from the client name.
     45 
     46     Optionally, override the generated name with a commandline provided version.
     47 
     48     @param client_hostname: string DNS name of device under test (the client).
     49     @param suffix: string suffix to append to the client hostname.
     50     @param cmdline_override: optional DNS name of companion device.  If this is
     51             given, it overrides the generated client based hostname.
     52     @param not_dnsname_msg: string message to include in the exception raised
     53             if the client hostname is found to be an IP address rather than a
     54             DNS name.
     55     @param allow_failure: boolean True iff we should return None on failure to
     56             infer a DNS name.
     57     @return string DNS name of companion device or None if |allow_failure|
     58             is True and no DNS name can be inferred.
     59 
     60     """
     61     if cmdline_override is not None:
     62         return cmdline_override
     63     if is_ip_address(client_hostname):
     64         logging.error('%r looks like an IP address?', client_hostname)
     65         if allow_failure:
     66             return None
     67         raise error.TestError(not_dnsname_msg)
     68     parts = client_hostname.split('.', 1)
     69     parts[0] = parts[0] + suffix
     70     return '.'.join(parts)
     71 
     72 
     73 def get_router_addr(client_hostname, cmdline_override=None):
     74     """Build a hostname for a WiFi router from the client hostname.
     75 
     76     Optionally override that hostname with the provided command line hostname.
     77 
     78     @param client_hostname: string DNS name of the client.
     79     @param cmdline_override: string DNS name of the router provided
     80             via commandline arguments.
     81     @return usable DNS name for router host.
     82 
     83     """
     84     return get_companion_device_addr(
     85             client_hostname,
     86             '-router',
     87             cmdline_override=cmdline_override,
     88             not_dnsname_msg=ROUTER_FAILURE_MESSAGE)
     89 
     90 
     91 def get_attenuator_addr(client_hostname,
     92                         cmdline_override=None,
     93                         allow_failure=False):
     94     """Build a hostname for a WiFi variable attenuator from the client hostname.
     95 
     96     Optionally override that hostname with the provided command line hostname.
     97 
     98     @param client_hostname: string DNS name of the client.
     99     @param cmdline_override: string DNS name of the variable attenuator
    100             controller provided via commandline arguments.
    101     @param allow_failure: boolean True iff we should return None on failure to
    102             infer a DNS name.
    103     @return usable DNS name for attenuator controller.
    104 
    105     """
    106     return get_companion_device_addr(
    107             client_hostname,
    108             '-attenuator',
    109             cmdline_override=cmdline_override,
    110             not_dnsname_msg=ATTENUATOR_FAILURE_MESSAGE,
    111             allow_failure=allow_failure)
    112 
    113 
    114 def get_tester_addr(client_hostname, cmdline_override=None):
    115     """Build a hostname for a Bluetooth test device from the client hostname.
    116 
    117     Optionally override that hostname with the provided command line hostname.
    118 
    119     @param client_hostname: string DNS name of the client.
    120     @param cmdline_override: string DNS name of the Bluetooth tester
    121             provided via commandline arguments.
    122     @return usable DNS name for Bluetooth tester device.
    123 
    124     """
    125     return get_companion_device_addr(
    126             client_hostname,
    127             '-router',
    128             cmdline_override=cmdline_override,
    129             not_dnsname_msg=BLUETOOTH_TESTER_FAILURE_MESSAGE)
    130