WSL2 networking mirrored - multicast support (Windows host <> WSL distro)

[borjamunozf]

Is your feature request related to a problem? Please describe.

Theorically, the documentation for WSL2 mirrored says that Multicast support is already in place, but there's a lof of issues linked to this:

#10735
#12122
#11966
#10614

I have faced myself this frustating problem through my company with a ROS2 app: Windows <> WSL2.
The default NAT mode is not a solution because it has other strange problem explained in #11966

Describe the solution you'd like

Multicast works in Mirrored mode between Windows and WSL Distro.

Describe alternatives you've considered

Additional context
The basic example I've been using to do quick test of multicast sender/receiver:

sender

import socket
import struct
import time

MULTICAST_GROUP = '224.1.1.1'  # Change to your desired multicast address
PORT = 5004  # Change to your desired port

# Create the socket
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.IPPROTO_UDP)

# Set the socket option to allow multicast
sock.setsockopt(socket.IPPROTO_IP, socket.IP_MULTICAST_TTL, 2)

# Send multicast packets
while True:
    message = b'This is a multicast message'
    sock.sendto(message, (MULTICAST_GROUP, PORT))
    print(f'Sent: {message}')
    time.sleep(1)  # Send a packet every second

receiver

import socket
import struct

MULTICAST_GROUP = '224.1.1.1'  # Match the address used in the sender
PORT = 5004  # Match the port used in the sender

# Create the socket
sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
sock.bind(('', PORT))

# Tell the operating system to add the socket to the multicast group
group = socket.inet_aton(MULTICAST_GROUP)
mreq = struct.pack('4sL', group, socket.INADDR_ANY)
sock.setsockopt(socket.IPPROTO_IP, socket.IP_ADD_MEMBERSHIP, mreq)

print(f'Ready to receive on {MULTICAST_GROUP}:{PORT}')

# Receive multicast packets
while True:
    data, addr = sock.recvfrom(1024)  # Buffer size is 1024 bytes
    print(f'Received message: {data} from {addr}')

[github-actions]

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View similar issues

Please view the issues below to see if they solve your problem, and if the issue describes your problem please consider closing this one and thumbs upping the other issue to help us prioritize it!

Open similar issues:

• Applications running on host not receiving UDP multicast packets sent from WSL2 (#12122), similarity score: 0.74

Closed similar issues:

• Support sending and Recieving AF_PACKET messages (#11446), similarity score: 0.73

Note: You can give me feedback by thumbs upping or thumbs downing this comment.

[borjamunozf]

/feature

[github-actions]

Diagnostic information

Found '/feature', adding tag 'feature'

[shixudong2020]

1.Windows host-> WSL distro
Run a multicast receiver simultaneously on the Windows host. Then, when the Windows host sends a multicast packet, it also sends a copy to the loopback device, and mirrors the multicast packet to the receiving direction of the WSL2's mirrored NIC. In this way, WSL2 can receive the multicast packet from the Windows host smoothly.
2.WSL distro->Windows host
hostAddressLoopback=true,and WSL executes "sudo ip route add 224.1.1.1 via 169.254.73.152 dev eth0 onlink", Here eth0 denotes the NIC on which the default route is located.Then Windows host can successfully receive multicast packets from WSL2 (mirrored)
for detail,please see WSL2 and multicast(https://blog.csdn.net/sxd2001/article/details/144649381)