发送广播数据报

Question

我需要向连接到我的网络的所有机器(服务器)发送广播数据报.

我正在使用NodeJS Multicast

客户

var dgram = require('dgram');
var message = new Buffer("Some bytes");
var client = dgram.createSocket("udp4");
client.send(message, 0, message.length, 41234, "localhost");
// If I'm in the same machine 'localhost' works
// I need to do something 192.168.0.255 or 255.255.255
client.close();

服务器

 var dgram = require("dgram");

 var server = dgram.createSocket("udp4");

 server.on("message", function (msg, rinfo) {
   console.log("server got: " + msg + " from " +
     rinfo.address + ":" + rinfo.port);
 });

 server.on("listening", function () {
   var address = server.address();
   console.log("server listening " + address.address + ":" + address.port);
 });

 server.bind(41234);

谢谢.

Answer 1

我花了很多时间试图在计算机之间进行UDP广播和多播.希望这使其他人更容易,因为这个主题很难在网上找到答案.这些解决方案适用于Node 0.12.5:

UDP广播

计算广播地址

广播地址=(〜子网掩码)| (主持人的IP地址) - 请参阅维基百科.使用ipconfig(Windows)或ifconfig(Linux),或签出网络掩码模块.

服务器(记得将BROADCAST_ADDR更改为正确的广播地址)

var PORT = 6024;
var BROADCAST_ADDR = "58.65.67.255";
var dgram = require('dgram'); 
var server = dgram.createSocket("udp4"); 

server.bind(function() {
    server.setBroadcast(true);
    setInterval(broadcastNew, 3000);
});

function broadcastNew() {
    var message = new Buffer("Broadcast message!");
    server.send(message, 0, message.length, PORT, BROADCAST_ADDR, function() {
        console.log("Sent '" + message + "'");
    });
}

客户

var PORT = 6024;
var dgram = require('dgram');
var client = dgram.createSocket('udp4');

client.on('listening', function () {
    var address = client.address();
    console.log('UDP Client listening on ' + address.address + ":" + address.port);
    client.setBroadcast(true);
});

client.on('message', function (message, rinfo) {
    console.log('Message from: ' + rinfo.address + ':' + rinfo.port +' - ' + message);
});

client.bind(PORT);

UDP组播

多播地址

查看IPv4多播地址空间注册表以及RFC 2365手册第6节中的更深入的说明,我们发现适当的本地范围多播地址是239.255.0.0/16和239.192.0.0/14(即,除非您获得许可使用其他的).

下面的多播代码在具有这些地址的Linux(以及许多其他平台)上运行良好.

Windows 8(显然是Windows 7,可能还有其他)通过特定接口发送和侦听多播,默认情况下它通常会选择错误的接口,因此您永远不会在另一台计算机上接收多播(您只能在localhost上接收它们).(我花了几个小时才通过测试来解决这个问题.)为了使代码可靠地工作,请更改代码,以便为要使用的接口指定主机的IP地址,如下所示:

服务器 - server.bind(SRC_PORT, HOST_IP_ADDRESS, function() ...

客户 - client.addMembership(MULTICAST_ADDR, HOST_IP_ADDRESS);

看看这些支持来源:NodeJS,Java,C#,以及一个有用的命令,可以查看您订阅的多播地址 -netsh interface ipv4 show joins

服务器

var SRC_PORT = 6025;
var PORT = 6024;
var MULTICAST_ADDR = '239.255.255.250';
var dgram = require('dgram');
var server = dgram.createSocket("udp4");

server.bind(SRC_PORT, function () {
    setInterval(multicastNew, 4000);
});

function multicastNew() {
    var message = new Buffer("Multicast message!");
    server.send(message, 0, message.length, PORT, MULTICAST_ADDR, function () {
        console.log("Sent '" + message + "'");
    });
}

客户

var PORT = 6024;
var MULTICAST_ADDR = '239.255.255.250';
var dgram = require('dgram');
var client = dgram.createSocket('udp4');

client.on('listening', function () {
    var address = client.address();
    console.log('UDP Client listening on ' + address.address + ":" + address.port);
});

client.on('message', function (message, rinfo) {
    console.log('Message from: ' + rinfo.address + ':' + rinfo.port + ' - ' + message);
});

client.bind(PORT, function () {
    client.addMembership(MULTICAST_ADDR);
});

Answer 2

我从未使用过Node.js,但我记得使用Berkely套接字(这似乎是最广泛使用的套接字实现),您需要启用SO_BROADCAST套接字选项才能将数据报发送到广播地址.查看dgram文档,似乎有一个功能.

var client = dgram.createSocket("udp4");
client.setBroadcast(true);
client.send(message, 0, message.length, 41234, "192.168.0.255");

您可能想以编程方式找到广播地址,但我无法帮助您.

Answer 3

我认为自节点0.10.0以来有些事情发生了变化,这对我现在起作用了:

//var broadcastAddress = "127.255.255.255";
var broadcastAddress = "192.168.0.255";

var message = new Buffer("Some bytes");

var client = dgram.createSocket("udp4");
client.bind();
client.on("listening", function () {
    client.setBroadcast(true);
    client.send(message, 0, message.length, 6623, broadcastAddress, function(err, bytes) {
        client.close();
    });
});

希望这有助于某人;)