const dgram = require('dgram');
const server = dgram.createSocket('udp4');
const multicastAddr = '224.100.100.100';

server.on('close', () => {
  console.log('socket已关闭');
});

server.on('error', (err) => {
  console.log(err);
});

server.on('listening', () => {
  console.log('socket正在监听中...');
  server.addMembership(multicastAddr); // 不写也行
  server.setBroadcast(true);
  server.setMulticastTTL(128);
  setInterval(() => {
    sendMsg();
  }, 1500);
});

server.on('message', (msg, rinfo) => {
  console.log(`receive client message from ${rinfo.address}:${rinfo.port}`);
});

function sendMsg() {
  console.log('sending');
  server.send('大家好啊，我是服务端广播消息', 8061, '10.8.93.255');
  server.send('大家好啊，我是服务端组播消息', 8061, multicastAddr);
}

server.bind('8060'); // 此处填写IP后无法组播

const dgram = require('dgram');
const client = dgram.createSocket('udp4');
const multicastAddr = '224.100.100.100';

client.on('close', () => {
  console.log('socket已关闭');
});

client.on('error', (err) => {
  console.log(err);
});
client.on('listening', () => {
  console.log('socket正在监听中...');
  client.addMembership(multicastAddr);
});
client.on('message', (msg, rinfo) => {
  console.log(`receive server message from ${rinfo.address}:${rinfo.port}：${msg}`);
});
client.bind(8061); // 此处必须绑定自己的局域网IP或者不填，填localhost是不行的