multicast with golang

multicast.go

package main

import (
	"fmt"
	"net"

	"golang.org/x/net/ipv4"
)

func main() {
	// resolve the multicast address and port
	addr, err := net.ResolveUDPAddr("udp", "224.0.0.1:8888")
	if err != nil {
		panic(err)
	}

	// resolve the local address and port
	laddr, err := net.ResolveUDPAddr("udp", "0.0.0.0:0")
	if err != nil {
		panic(err)
	}

	// create the local UDP connection
	conn, err := net.ListenUDP("udp", laddr)
	if err != nil {
		panic(err)
	}

	// join the multicast group
	ifi, err := net.InterfaceByName("enxa8637d613a92") // replace with your network interface name
	if err != nil {
		panic(err)
	}
	p := ipv4.NewPacketConn(conn)
	if err := p.JoinGroup(ifi, addr); err != nil {
		panic(err)
	}

	// start a goroutine to receive messages
	go func() {
		for {
			buf := make([]byte, 1024)
			n, _, _, err := p.ReadFrom(buf)
			if err != nil {
				panic(err)
			}
			fmt.Printf("Received message: %s\n", string(buf[:n]))
		}
	}()

	// send some messages to the multicast group
	for i := 0; i < 10; i++ {
		message := fmt.Sprintf("Hello, multicast group! (%d)", i)
		if _, err := p.WriteTo([]byte(message), nil, addr); err != nil {
			panic(err)
		}
		fmt.Printf("Sent message: %s\n", message)
	}
}

use ListenUDP to create a local UDP connection and then join the multicast group using the JoinGroup method of an ipv4.PacketConn structure, which is created from the net.UDPConn. We also use the WriteTo method of the ipv4.PacketConn to send messages to the group. Finally, we use the ReadFrom method of the ipv4.PacketConn to receive messages from the group in a goroutine.

Note that you'll need to replace "enxa8637d613a92" with the name of the network interface you want to use for multicasting, and ensure that your network supports multicast.