I am writing a couple of functions to allow me to send out a UDP broadcast / multicast using both IPv4 and IPv6. The follow code does this. The problem I have is that it only does this for a single adapter. If I have two network adapters fitted to my PC it doesn’t send the broadcast out on both. Is it possible to have a single socket configured to handle both IPv4 and IPv6 and to send and receive on all NICs? Or do I have to create separate sockets for each IP address?
public void CreateBroadcaster(CancellationToken cancellationToken, int discoveryPort, int advancePort)
{
_cancellationToken = cancellationToken;
_broadcastEndpoint = new IPEndPoint(IPAddress.Broadcast, advancePort);
var epLocal = new IPEndPoint(IPAddress.IPv6Any, discoveryPort);
_broadcaster = new UdpClient(epLocal);
var soc = new Socket(AddressFamily.InterNetworkV6, SocketType.Dgram, ProtocolType.Udp);
soc.SetSocketOption(SocketOptionLevel.IPv6, SocketOptionName.IPv6Only, false);
_broadcaster.Client = soc;
_broadcaster.Client.DualMode = true;
_broadcaster.Client.Bind(epLocal);
_broadcaster.EnableBroadcast = true;
_broadcaster.MulticastLoopback = true;
_broadcaster.Client.SetSocketOption(
SocketOptionLevel.IPv6,
SocketOptionName.AddMembership,
new IPv6MulticastOption(IPAddress.Parse("ff02::1")));
}
public void SendPingsOnAdapterLocalSubnets()
{
_broadcaster.Send(_sendData, _sendData.Length, _broadcastEndpoint);
}
You need 2 separate sockets. On the low level, the sockaddr struct will have one or other. IPv4(AF_INET) or IPv6(AF_INET6).
http://www.gnu.org/software/libc/manual/html_node/Address-Formats.html#Address-Formats
Related
I am new to multicast programming. So far I can successfully send and receive multicast messages from two separate processes (a sender and a receiver). My problem is with the receiver...
ReceiverCode:
private static void ReceiveMulticastMessages()
{
var groupEndPoint = new IPEndPoint(IPAddress.Parse("238.8.8.8"), 23888);
var localEndPoint = new IPEndPoint(IPAddress.Any, 23888);
using (var udpClient = new UdpClient())
{
udpClient.Client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
udpClient.Client.Bind(localEndPoint);
udpClient.JoinMulticastGroup(groupEndPoint.Address, localEndPoint.Address);
while (true)
{
var remoteEndPoint = new IPEndPoint(IPAddress.Any, 0);
var bytes = udpClient.Receive(ref remoteEndPoint);
var message = Encoding.ASCII.GetString(bytes);
Console.WriteLine(message);
}
}
}
The above code works as long as I specify port 23888 for the localEndPoint. If I change the local port number, no messages are received. I would prefer to set it to 0 so the OS could choose the port. Why can I not specify a different local port than that of multicast group?
Assuming the local endpoint port must match the multicast group port, how does a client deal with a local port conflict?
On the flip side, how can an application (a multicast sender) choose a multicast group port such that any subscribers will not have a port conflict?
When sending any UDP message (not just muticast messages), the port that the sender sends to must match the port that the receiver is listening on. That's how messages get to the right place. If a message is sent to a port other that the one the receiver is bound to, the receiver won't get it.
So a port number needs to be defined that the receiver(s) will listen on and the server will send to.
I'm trying to implement Hole punching using C# but unfortunately I spent hours to figure out why it doesn't work for me. Here is my problem:
I have a third part server that I can manage all external IPs for the peers on, and of course my router is behind a NAT, and I assume all my peers are also behind NATs.
Say if I managed to figure out all slaves (peers), End points (external ips). Where to put the external ip address of my server which runs on my pc (not the third party one), and where to put the peer ip address?
This is my code:
public void HolePunch(String ServerIp, Int32 Port) // if I put my external ip here I get Exception (An address incompatible with the requested protocol was used)
{
IPEndPoint LocalPt = new IPEndPoint(Dns.GetHostEntry(Dns.GetHostName()).AddressList[0], Port);
UdpClient Client = new UdpClient();
Client.ExclusiveAddressUse = false;
Client.Client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
Client.Client.Bind(LocalPt);
IPEndPoint RemotePt = new IPEndPoint(IPAddress.Parse(ServerIp), Port);
// This Part Sends your local endpoint to the server so if the two peers are on the same nat they can bypass it, you can omit this if you wish to just use the remote endpoint.
byte[] IPBuffer = System.Text.Encoding.UTF8.GetBytes(Dns.GetHostEntry(Dns.GetHostName()).AddressList[0].ToString());
byte[] LengthBuffer = BitConverter.GetBytes(IPBuffer.Length);
byte[] PortBuffer = BitConverter.GetBytes(Port);
byte[] Buffer = new byte[IPBuffer.Length + LengthBuffer.Length + PortBuffer.Length];
LengthBuffer.CopyTo(Buffer,0);
IPBuffer.CopyTo(Buffer, LengthBuffer.Length);
PortBuffer.CopyTo(Buffer, IPBuffer.Length + LengthBuffer.Length);
Client.BeginSend(Buffer, Buffer.Length, RemotePt, new AsyncCallback(SendCallback), Client);
// Wait to receve something
BeginReceive(Client, Port);
// you may want to use a auto or manual ResetEvent here and have the server send back a confirmation, the server should have now stored your local (you sent it) and remote endpoint.
// you now need to work out who you need to connect to then ask the server for there remote and local end point then need to try to connect to the local first then the remote.
// if the server knows who you need to connect to you could just have it send you the endpoints as the confirmation.
// you may also need to keep this open with a keepalive packet untill it is time to connect to the peer or peers.
// once you have the endpoints of the peer you can close this connection unless you need to keep asking the server for other endpoints
Client.Close();
}
public void ConnectToPeer(String PeerIp, Int32 Port)
{
IPEndPoint LocalPt = new IPEndPoint(Dns.GetHostEntry(Dns.GetHostName()).AddressList[0], Port);
UdpClient Client = new UdpClient();
Client.ExclusiveAddressUse = false;
Client.Client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
Client.Client.Bind(LocalPt);
IPEndPoint RemotePt = new IPEndPoint(IPAddress.Parse(PeerIp), Port);
Client.Connect(RemotePt);
//you may want to keep the peer client connections in a list.
BeginReceive(Client, Port);
}
public void SendCallback(IAsyncResult ar)
{
UdpClient Client = (UdpClient)ar.AsyncState;
Client.EndSend(ar);
}
public void BeginReceive(UdpClient Client, Int32 Port)
{
IPEndPoint ListenPt = new IPEndPoint(IPAddress.Any, Port);
Object[] State = new Object[] { Client, ListenPt };
Client.BeginReceive(new AsyncCallback(ReceiveCallback), State);
}
public void ReceiveCallback(IAsyncResult ar)
{
UdpClient Client = (UdpClient)((Object[])ar.AsyncState)[0];
IPEndPoint ListenPt = (IPEndPoint)((Object[])ar.AsyncState)[0];
Byte[] receiveBytes = Client.EndReceive(ar, ref ListenPt);
}
EDIT :
the code works will if I give it my local ip and if my clients in my pc .. but if I supply it an external ip it doesn't work ( the exception in the first line comment )
I've made a simple chat application in c#.net that sends and receives data between 2 computers.
So, I used this method to send the data:
int port = 11000;
private void send(string data, string ip)
{
Socket sending_socket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
IPEndPoint sending_end_point = null;
byte[] send_buffer = Encoding.ASCII.GetBytes(data);
sending_end_point = new IPEndPoint(IPAddress.Parse(ip), port);
try { sending_socket.SendTo(send_buffer, sending_end_point); }
catch { }
}
And to receive I used this:
string receiveddata = "";
private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
UdpClient listener = new UdpClient(port);
IPEndPoint groupEP = new IPEndPoint(IPAddress.Any, port);
byte[] receive_byte_array;
try
{
receive_byte_array = listener.Receive(ref groupEP);
receiveddata = Encoding.ASCII.GetString(receive_byte_array, 0, receive_byte_array.Length);
}
catch { }
listener.Close();
}
This works without any problems between 2 computers on a LAN, but I would like to know (if possible) how to do the same thing over the Internet.
From what I've searched on the Internet, it seems that I have to use port-forwarding in order to do that, so I already did that, but I don't know what should I do know.
So my question is, how should I change this code (if I have to) so I could send and receive data (UDP) over the internet, assuming I have port-forwarded correctly already and assuming I know the external IPs of both routers?
Thank you in advance.
This should work just fine, as long as your (public) IP-address is correct and the ports are forwarded correctly on your router (meaning, forwarded to the correct private IP, on the correct protocol, in your case UDP).
You are aware that this is UDP though, so it's not reliable data transfer.
I'm trying to do a webservice discovery using WCF's DiscoveryClient using this code:
// Setup the discovery client (WSDiscovery April 2005)
DiscoveryEndpoint discoveryEndpoint = new UdpDiscoveryEndpoint(DiscoveryVersion.WSDiscoveryApril2005);
DiscoveryClient discoveryClient = new DiscoveryClient(discoveryEndpoint);
// Setup the wanted device criteria
FindCriteria criteria = new FindCriteria();
criteria.ScopeMatchBy = new Uri("http://schemas.xmlsoap.org/ws/2005/04/discovery/rfc3986");
criteria.Scopes.Add(new Uri("onvif://www.onvif.org/"));
// Go find!
criteria.Duration = TimeSpan.FromMilliseconds(duration);
discoveryClient.FindAsync(criteria, this);
This works very well on a machine with a single IP address (10.1.4.25) assigned to the single network interface. The broadcast is sent from 10.1.4.25 to 239.255.255.250, and I get responses from 5 devices all on the same subnet.
However, when the machine has multiple IPs on the same interface, it seems to pick a single source IP and sends the request from that.
In this case, I get a reply from a single device giving a 169.254 address.
I have tried setting UdpDiscoveryEndpoint.TransportSettings.MulticastInterfaceId to a suitable interface ID which hasn't helped as it identifies a single interface, not a specific IP.
The UdpDiscoveryEndpoint.ListenUri property also returns the multicast address, and so won't effect the source IP.
UdpDiscoveryEndpoint.Address is the URN for the discovery protocol.
Is there any way I can force it to send from a specific IP address, or ideally, multiple requests on each configured IP?
I have also tried ONVIF Device Manager that seems to have the same problem.
Note that this is not about making a service bind to a specific, or "all address" IP. It is about the IP a discovery request is sent from.
Well, I had the same problem and after some days of research, reading ONVIF documents and learning some tips about multicasting, I developed this code which works fine.
As an example the main IP address on my network adapter is 192.168.80.55 and I also set another IP(192.168.0.10) in advanced settings. With use of this code I can discover device service of a camera with the IP address of 192.168.0.12.
The most important part of this sample is "DeepDiscovery" method which contains the main idea of iteration on network addresses and multicasting proper Probe message.
I recommend deserialization of the response in "GetSocketResponse" method. Currently, just I extract the service URI using Regex.
As mentioned in this article (https://msdn.microsoft.com/en-us/library/dd456791(v=vs.110).aspx):
For WCF Discovery to work correctly, all NICs (Network Interface
Controller) should only have 1 IP address.
I am doing the exact action that WS-Discovery does and using the standard 3702 port, but I myself build the SOAP envelope
and use Socket class for sending the packet for all IP addresses that have been set for the network interface controller.
class Program
{
static readonly List<string> addressList = new List<string>();
static readonly IPAddress multicastAddress = IPAddress.Parse("239.255.255.250");
const int multicastPort = 3702;
const int unicastPort = 0;
static void Main(string[] args)
{
DeepDiscovery();
Console.ReadKey();
}
public static void DeepDiscovery()
{
string probeMessageTemplate = #"<s:Envelope xmlns:s=""http://www.w3.org/2003/05/soap-envelope"" xmlns:a=""http://schemas.xmlsoap.org/ws/2004/08/addressing""><s:Header><a:Action s:mustUnderstand=""1"">http://schemas.xmlsoap.org/ws/2005/04/discovery/Probe</a:Action><a:MessageID>urn:uuid:{messageId}</a:MessageID><a:ReplyTo><a:Address>http://schemas.xmlsoap.org/ws/2004/08/addressing/role/anonymous</a:Address></a:ReplyTo><a:To s:mustUnderstand=""1"">urn:schemas-xmlsoap-org:ws:2005:04:discovery</a:To></s:Header><s:Body><Probe xmlns=""http://schemas.xmlsoap.org/ws/2005/04/discovery""><d:Types xmlns:d=""http://schemas.xmlsoap.org/ws/2005/04/discovery"" xmlns:dp0=""http://www.onvif.org/ver10/device/wsdl"">dp0:Device</d:Types></Probe></s:Body></s:Envelope>";
foreach (IPAddress localIp in
Dns.GetHostAddresses(Dns.GetHostName()).Where(i => i.AddressFamily == AddressFamily.InterNetwork))
{
var socket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
socket.Bind(new IPEndPoint(localIp, unicastPort));
socket.SetSocketOption(SocketOptionLevel.IP, SocketOptionName.AddMembership, new MulticastOption(multicastAddress, localIp));
socket.SetSocketOption(SocketOptionLevel.IP, SocketOptionName.MulticastTimeToLive, 255);
socket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
socket.MulticastLoopback = true;
var thread = new Thread(() => GetSocketResponse(socket));
var probeMessage = probeMessageTemplate.Replace("{messageId}", Guid.NewGuid().ToString());
var message = Encoding.UTF8.GetBytes(probeMessage);
socket.SendTo(message, 0, message.Length, SocketFlags.None, new IPEndPoint(multicastAddress, multicastPort));
thread.Start();
}
}
public static void GetSocketResponse(Socket socket)
{
try
{
while (true)
{
var response = new byte[3000];
EndPoint ep = socket.LocalEndPoint;
socket.ReceiveFrom(response, ref ep);
var str = Encoding.UTF8.GetString(response);
var matches = Regex.Matches(str, #"http://\b\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}\b/onvif/device_service");
foreach (var match in matches)
{
var value = match.ToString();
if (!addressList.Contains(value))
{
Console.WriteLine(value);
addressList.Add(value);
}
}
//...
}
}
catch (Exception ex)
{
Console.WriteLine(ex);
//...
}
}
}
I've the following code to read multicast message coming from the network, for a specified IP+Port
private static void ReceiveMessages(int port, string ip, CancellationToken token)
{
Task.Factory.StartNew(() =>
{
using (var mUdpClientReceiver = new UdpClient())
{
var mReceivingEndPoint = new IPEndPoint(IPAddress.Any, port);
mUdpClientReceiver.ExclusiveAddressUse = false;
mUdpClientReceiver.Client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
mUdpClientReceiver.ExclusiveAddressUse = false;
mUdpClientReceiver.Client.Bind(mReceivingEndPoint);
mUdpClientReceiver.JoinMulticastGroup(IPAddress.Parse(ip), 255);
while (!token.IsCancellationRequested)
{
byte[] receive = mUdpClientReceiver.Receive(ref mReceivingEndPoint);
Console.WriteLine("Message received from {0} ",mReceivingEndPoint);
}
}
});
}
I've two network adapter from which I've data coming on this multicast ip+port(confirmed by two instances of wireshark monitoring each network adapter). I see on wireshark a lot of traffic coming on those port+Ip) for both network cards.
The problem is that on my console, I only see messages coming from one network card.
I double checked with netstat, I don't have any other software listening on my port:
So why am I getting traffic from only one of my two network cards?
EDIT:
I even tried the following:
private static void ReceiveMessages(int port, string ip, CancellationToken token, IEnumerable<IPAddress> ipAddresses)
{
foreach (IPAddress ipAddress in ipAddresses)
{
IPAddress ipToUse = ipAddress;
Task.Factory.StartNew(() =>
{
using (var mUdpClientReceiver = new UdpClient())
{
var mReceivingEndPoint = new IPEndPoint(ipToUse, port);
mUdpClientReceiver.ExclusiveAddressUse = false;
mUdpClientReceiver.Client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
mUdpClientReceiver.Client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.Broadcast, 1);
mUdpClientReceiver.Client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.DontRoute, 1);
mUdpClientReceiver.ExclusiveAddressUse = false;
mUdpClientReceiver.Client.Bind(mReceivingEndPoint);
mUdpClientReceiver.JoinMulticastGroup(IPAddress.Parse(ip), 255);
Console.WriteLine("Starting to listen on "+ipToUse);
while (!token.IsCancellationRequested)
{
byte[] receive = mUdpClientReceiver.Receive(ref mReceivingEndPoint);
Console.WriteLine("Message received from {0} on {1}", mReceivingEndPoint,ipToUse);
}
}
});
}
}
I see the "Starting to listen on theCorrectIP" twice(for my two IPs), but it still display only data coming from one network card.
EDIT 2
I did notice something else that is strange too. If I disable the interface on which I receive all data, and then start the software, I now get data from the other interface. If I activate again the interface and restart the software, I still get the traffic on the non-deactivated card.
And I know for sure that I've devices that respond to me, that are connected only to one network(not both)
EDIT 3
Another thing: if I send a message from me(localhost), on all network card that I've, I see them coming on my two network interfaces. BUT, if I start my program twice, only the first programm get messages, not the second one.
Edit 4
Additional info, following the first comment:
I've two ethernet cards, one with the 10.10.24.78 ip, the other with the 10.9.10.234 ip.
It's not me that send data, but network pieces(the port 5353 with this ip is a know multicast address used for mDNS, so I should receive traffic from things like printer, itunes, macs, and some other pieces of software we created). Data are multicasted on the ip
224.0.0.251 and port 5353.
Here is a code that you could use to send data on severals IPs, but like I described, if you start it in local it almost works(except that only one local client receive the message).
private static void SendManuallyOnAllCards(int port, string multicastAddress, IEnumerable<IPAddress> ipAddresses)
{
foreach (IPAddress remoteAddress in ipAddresses)
{
IPAddress ipToUse = remoteAddress;
using (var mSendSocket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp))
{
mSendSocket.SetSocketOption(SocketOptionLevel.IP, SocketOptionName.AddMembership,
new MulticastOption(IPAddress.Parse(multicastAddress)));
mSendSocket.SetSocketOption(SocketOptionLevel.IP, SocketOptionName.MulticastTimeToLive, 255);
mSendSocket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
var ipep = new IPEndPoint(ipToUse, port);
//IPEndPoint ipep = new IPEndPoint(IPAddress.Parse(multicastAddress), port);
mSendSocket.Bind(ipep);
mSendSocket.Connect(ipep);
byte[] bytes = Encoding.ASCII.GetBytes("This is my welcome message");
mSendSocket.Send(bytes, bytes.Length, SocketFlags.None);
}
}
}
EDIT 5
Here is the result of my route print(Didn't know that command), and on my two IPs, I always receive data on the 10.9.10.234
Edit 6
I tried several other things:
Use a socket to receive instead of the UdpClient --> Didn't worked
Set some addition socketOption on the reader(DontRoute =1, Broadcast=1) -->Didn't worked
Specify the MulticastInterface that the reader Socket has to use(using socketOption MulticastInterface) --> Didn't work
I had the same problem that I wanted to receive multicasts from all my network interfaces. As EJP already said, you need to call JoinMulticastGroup(IPAddress multicastAddr, IPAddress localAddress) on the UdpClient for all network interfaces:
int port = 1036;
IPAddress multicastAddress = IPAddress.Parse("239.192.1.12");
client = new UdpClient(new IPEndPoint(IPAddress.Any, port));
// list of UdpClients to send multicasts
List<UdpClient> sendClients = new List<UdpClient>();
// join multicast group on all available network interfaces
NetworkInterface[] networkInterfaces = NetworkInterface.GetAllNetworkInterfaces();
foreach (NetworkInterface networkInterface in networkInterfaces)
{
if ((!networkInterface.Supports(NetworkInterfaceComponent.IPv4)) ||
(networkInterface.OperationalStatus != OperationalStatus.Up))
{
continue;
}
IPInterfaceProperties adapterProperties = networkInterface.GetIPProperties();
UnicastIPAddressInformationCollection unicastIPAddresses = adapterProperties.UnicastAddresses;
IPAddress ipAddress = null;
foreach (UnicastIPAddressInformation unicastIPAddress in unicastIPAddresses)
{
if (unicastIPAddress.Address.AddressFamily != AddressFamily.InterNetwork)
{
continue;
}
ipAddress = unicastIPAddress.Address;
break;
}
if (ipAddress == null)
{
continue;
}
client.JoinMulticastGroup(multicastAddress, ipAddress);
UdpClient sendClient = new UdpClient(new IPEndPoint(ipAddress, port));
sendClients.Add(sendClient);
}
I am also creating a list of UdpClients so I can send my multicasts on all network interfaces.
I finally found how to do it!
In fact, if I keep exactly the same code, but using it with async methods, it work!!! I just can't understand why it doesn't work with sync method(if someone knows, you're welcome to tell me :) )
Since I've lost 3 days on this, I think it worth an example:
private static void ReceiveAsync(int port, string address, IEnumerable<IPAddress> localAddresses)
{
IPAddress multicastAddress = IPAddress.Parse(address);
foreach (IPAddress localAddress in localAddresses)
{
var udpClient = new UdpClient(AddressFamily.InterNetwork);
udpClient.Client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
udpClient.Client.Bind(new IPEndPoint(localAddress, port));
udpClient.JoinMulticastGroup(multicastAddress, localAddress);
udpClient.BeginReceive(OnReceiveSink,
new object[]
{
udpClient, new IPEndPoint(localAddress, ((IPEndPoint) udpClient.Client.LocalEndPoint).Port)
});
}
}
And the async method:
private static void OnReceiveSink(IAsyncResult result)
{
IPEndPoint ep = null;
var args = (object[]) result.AsyncState;
var session = (UdpClient) args[0];
var local = (IPEndPoint) args[1];
byte[] buffer = session.EndReceive(result, ref ep);
//Do what you want here with the data of the buffer
Console.WriteLine("Message received from " + ep + " to " + local);
//We make the next call to the begin receive
session.BeginReceive(OnReceiveSink, args);
}
I hope that helps ;)
You need to join the multicast group via all available interfaces. By default, the outgoing IGMP JOIN message will be routed according to the unicast routing tables, which will send it out via the 'cheapest' route, using whichever NIC accesses that route. If your multicast group can be sourced via more than one of those routes, you need to iterate.