我创建了一个小程序来测试UPnP组播(使用Visual C# 2010 Express,在Windows 7 Professional 64位上运行)。我可以接收来自网络中的UPnP设备的UPnP NOTIFY消息。但是当我发送M-SEARCH消息时,却没有得到回应。
我已经在iOS环境下进行了相同代码的测试(使用Monotouch for iOS,在Mac上运行的iPhone模拟器)。在那里,它运行良好,并且我能够获得来自我的UPnP设备的所有搜索响应。我也可以从我的Windows程序中看到M-SEARCH消息。
看起来Windows(或防火墙?)正在隐藏搜索响应。有任何想法吗?
这是代码:
IPEndPoint LocalEndPoint = new IPEndPoint(IPAddress.Any, 1900);
IPEndPoint MulticastEndPoint = new IPEndPoint(IPAddress.Parse("239.255.255.250"), 1900);
Socket UdpSocket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
UdpSocket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
UdpSocket.Bind(LocalEndPoint);
UdpSocket.SetSocketOption(SocketOptionLevel.IP, SocketOptionName.AddMembership, new MulticastOption(MulticastEndPoint.Address, IPAddress.Any));
UdpSocket.SetSocketOption(SocketOptionLevel.IP, SocketOptionName.MulticastTimeToLive, 2);
UdpSocket.SetSocketOption(SocketOptionLevel.IP, SocketOptionName.MulticastLoopback, true);
Console.WriteLine("UDP-Socket setup done...\r\n");
string SearchString = "M-SEARCH * HTTP/1.1\r\nHOST:239.255.255.250:1900\r\nMAN:\"ssdp:discover\"\r\nST:ssdp:all\r\nMX:3\r\n\r\n";
UdpSocket.SendTo(Encoding.UTF8.GetBytes(SearchString), SocketFlags.None, MulticastEndPoint);
Console.WriteLine("M-Search sent...\r\n");
byte[] ReceiveBuffer = new byte[64000];
int ReceivedBytes = 0;
while (true)
{
if (UdpSocket.Available > 0)
{
ReceivedBytes = UdpSocket.Receive(ReceiveBuffer, SocketFlags.None);
if (ReceivedBytes > 0)
{
Console.WriteLine(Encoding.UTF8.GetString(ReceiveBuffer, 0, ReceivedBytes));
}
}
}