1 #!/usr/bin/env python2.7 2 # Copyright 2015 gRPC authors. 3 # 4 # Licensed under the Apache License, Version 2.0 (the "License"); 5 # you may not use this file except in compliance with the License. 6 # You may obtain a copy of the License at 7 # 8 # http://www.apache.org/licenses/LICENSE-2.0 9 # 10 # Unless required by applicable law or agreed to in writing, software 11 # distributed under the License is distributed on an "AS IS" BASIS, 12 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 # See the License for the specific language governing permissions and 14 # limitations under the License. 15 16 """Makes DNS queries for A records to specified servers""" 17 18 import argparse 19 import threading 20 import time 21 import twisted.internet.task as task 22 import twisted.names.client as client 23 import twisted.internet.reactor as reactor 24 25 26 def main(): 27 argp = argparse.ArgumentParser(description='Make DNS queries for A records') 28 argp.add_argument('-s', '--server_host', default='127.0.0.1', type=str, 29 help='Host for DNS server to listen on for TCP and UDP.') 30 argp.add_argument('-p', '--server_port', default=53, type=int, 31 help='Port that the DNS server is listening on.') 32 argp.add_argument('-n', '--qname', default=None, type=str, 33 help=('Name of the record to query for. ')) 34 argp.add_argument('-t', '--timeout', default=1, type=int, 35 help=('Force process exit after this number of seconds.')) 36 args = argp.parse_args() 37 def OnResolverResultAvailable(result): 38 answers, authority, additional = result 39 for a in answers: 40 print(a.payload) 41 def BeginQuery(reactor, qname): 42 servers = [(args.server_host, args.server_port)] 43 resolver = client.Resolver(servers=servers) 44 deferred_result = resolver.lookupAddress(args.qname) 45 deferred_result.addCallback(OnResolverResultAvailable) 46 return deferred_result 47 task.react(BeginQuery, [args.qname]) 48 49 if __name__ == '__main__': 50 main() 51
