tests/topotests/pim-basic/mcast-rx.py

   1 #!/usr/bin/env python
   2 #
   3 # mcast-rx.py
   4 #
   5 # Copyright (c) 2018 Cumulus Networks, Inc.
   6 #
   7 # Permission to use, copy, modify, and/or distribute this software
   8 # for any purpose with or without fee is hereby granted, provided
   9 # that the above copyright notice and this permission notice appear
  10 # in all copies.
  11 #
  12 # THE SOFTWARE IS PROVIDED "AS IS" AND Cumulus Networks DISCLAIMS ALL WARRANTIES
  13 # WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  14 # MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL NETDEF BE LIABLE FOR
  15 # ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY
  16 # DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
  17 # WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS
  18 # ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
  19 # OF THIS SOFTWARE.
  20 #
  21 """
  22 Subscribe to a multicast group so that the kernel sends an IGMP JOIN
  23 for the multicast group we subscribed to.
  24 """
  25
  26 import argparse
  27 import logging
  28 import re
  29 import os
  30 import socket
  31 import subprocess
  32 import struct
  33 import sys
  34 import time
  35
  36
  37 def ifname_to_ifindex(ifname):
  38     output = subprocess.check_output("ip link show %s" % ifname, shell=True)
  39     first_line = output.split('\n')[0]
  40     re_index = re.search('^(\d+):', first_line)
  41
  42     if re_index:
  43         return int(re_index.group(1))
  44
  45     log.error("Could not parse the ifindex for %s out of\n%s" % (ifname, first_line))
  46     return None
  47
  48
  49 # Thou shalt be root
  50 if os.geteuid() != 0:
  51     sys.stderr.write('ERROR: You must have root privileges\n')
  52     sys.exit(1)
  53
  54
  55 logging.basicConfig(level=logging.DEBUG, format='%(asctime)s %(levelname)5s: %(message)s')
  56
  57 # Color the errors and warnings in red
  58 logging.addLevelName(logging.ERROR, "\033[91m  %s\033[0m" % logging.getLevelName(logging.ERROR))
  59 logging.addLevelName(logging.WARNING, "\033[91m%s\033[0m" % logging.getLevelName(logging.WARNING))
  60 log = logging.getLogger(__name__)
  61
  62 parser = argparse.ArgumentParser(description='Multicast RX utility',
  63                                  version='1.0.0')
  64 parser.add_argument('group', help='Multicast IP')
  65 parser.add_argument('ifname', help='Interface name')
  66 parser.add_argument('--port', help='UDP port', default=1000)
  67 parser.add_argument('--sleep', help='Time to sleep before we stop waiting',
  68                     default = 5)
  69 args = parser.parse_args()
  70
  71 # Create the datagram socket
  72 sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
  73 sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
  74 sock.bind((args.group, args.port))
  75
  76 newpid = os.fork()
  77
  78 if newpid == 0:
  79     ifindex = ifname_to_ifindex(args.ifname)
  80     mreq = struct.pack("=4sLL", socket.inet_aton(args.group), socket.INADDR_ANY, ifindex)
  81     sock.setsockopt(socket.IPPROTO_IP, socket.IP_ADD_MEMBERSHIP, mreq)
  82     time.sleep(float(args.sleep))
  83     sock.close()