1 files changed, 79 insertions, 0 deletions
diff --git a/tests/topotests/pim_basic/mcast-rx.py b/tests/topotests/pim_basic/mcast-rx.py
new file mode 100755
index 0000000..d05ed1a
--- /dev/null
+++ b/tests/topotests/pim_basic/mcast-rx.py
@@ -0,0 +1,79 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: ISC
+#
+# mcast-rx.py
+#
+# Copyright (c) 2018 Cumulus Networks, Inc.
+#
+"""
+Subscribe to a multicast group so that the kernel sends an IGMP JOIN
+for the multicast group we subscribed to.
+"""
+
+import argparse
+import logging
+import re
+import os
+import socket
+import subprocess
+import struct
+import sys
+import time
+
+
+def ifname_to_ifindex(ifname):
+    output = subprocess.check_output(
+        "ip link show %s" % ifname, shell=True, universal_newlines=True
+    )
+    first_line = output.split("\n")[0]
+    re_index = re.search("^(\d+):", first_line)
+
+    if re_index:
+        return int(re_index.group(1))
+
+    log.error("Could not parse the ifindex for %s out of\n%s" % (ifname, first_line))
+    return None
+
+
+# Thou shalt be root
+if os.geteuid() != 0:
+    sys.stderr.write("ERROR: You must have root privileges\n")
+    sys.exit(1)
+
+
+logging.basicConfig(
+    level=logging.DEBUG, format="%(asctime)s %(levelname)5s: %(message)s"
+)
+
+# Color the errors and warnings in red
+logging.addLevelName(
+    logging.ERROR, "\033[91m  %s\033[0m" % logging.getLevelName(logging.ERROR)
+)
+logging.addLevelName(
+    logging.WARNING, "\033[91m%s\033[0m" % logging.getLevelName(logging.WARNING)
+)
+log = logging.getLogger(__name__)
+
+parser = argparse.ArgumentParser(description="Multicast RX utility")
+
+parser.add_argument("group", help="Multicast IP")
+parser.add_argument("ifname", help="Interface name")
+parser.add_argument("--port", help="UDP port", default=1000)
+parser.add_argument("--sleep", help="Time to sleep before we stop waiting", default=5)
+args = parser.parse_args()
+
+# Create the datagram socket
+sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+sock.bind((args.group, args.port))
+
+newpid = os.fork()
+
+if newpid == 0:
+    ifindex = ifname_to_ifindex(args.ifname)
+    mreq = struct.pack(
+        "=4sLL", socket.inet_aton(args.group), socket.INADDR_ANY, ifindex
+    )
+    sock.setsockopt(socket.IPPROTO_IP, socket.IP_ADD_MEMBERSHIP, mreq)
+    time.sleep(float(args.sleep))
+    sock.close()