Multicast test send and receive

combined_test.py

import socket
import struct
import time

test_groups = ['224.1.1.1', '239.255.255.255']
test_interfaces = ['127.0.0.1', '192.168.42.42']

port = 15007

receivers = []

for rcv_interface in test_interfaces:
    rcv = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
    rcv.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
    rcv.bind((rcv_interface, port))

    for rcv_group in test_groups:
        mreq = struct.pack(
            "4s4s", socket.inet_aton(rcv_group),
            socket.inet_aton(rcv_interface))
        rcv.setsockopt(socket.IPPROTO_IP, socket.IP_ADD_MEMBERSHIP, mreq)

    rcv.settimeout(0)
    receivers.append(rcv)

def receive():
    received = False
    for rcv in receivers:
        try:
            data, address = rcv.recvfrom(10240)
            received = True
            print(f"From: {address}, received: {data}")
        except socket.timeout:
            pass
        except BlockingIOError:
            pass

    if not received:
        print("No data received")

def send(group, interface):
    #print(f"Test from {group} {interface}")
    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP)
    sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, 2)
    sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_LOOP, 1)
    sock.setsockopt(
        socket.IPPROTO_IP, socket.IP_MULTICAST_IF, socket.inet_aton(interface))
    mreq = struct.pack(
        "4s4s", socket.inet_aton(group),
        socket.inet_aton(interface))
    sock.setsockopt(socket.IPPROTO_IP, socket.IP_ADD_MEMBERSHIP, mreq)

    data = f"multicast send - group: {group} interface: {interface}"
    data = data.encode()

    try:
        sock.sendto(data, (group, port))
    except socket.timeout:
        pass
    except OSError as e:
       print(e)

    receive()

for test_group in test_groups:
    for test_interface in test_interfaces:
        send(test_group, test_interface)
        time.sleep(0.5)