// Must return non-null/non-empty array unless exceptionToBeThrown is has been set
protected override UdpSocket[] GetSendSockets(Message message, out IPEndPoint remoteEndPoint, out Exception exceptionToBeThrown)
{
Fx.Assert(message != null, "message can't be null");
UdpSocket[] socketList = null;
exceptionToBeThrown = null;
remoteEndPoint = null;
Uri destination;
bool isVia = false;
if (message.Properties.Via != null)
{
destination = message.Properties.Via;
isVia = true;
}
else if (message.Headers.To != null)
{
destination = message.Headers.To;
}
else
{
throw FxTrace.Exception.AsError(new InvalidOperationException(SR.ToOrViaRequired));
}
this.ValidateDestinationUri(destination, isVia);
if (destination.HostNameType == UriHostNameType.IPv4 || destination.HostNameType == UriHostNameType.IPv6)
{
remoteEndPoint = new IPEndPoint(IPAddress.Parse(destination.DnsSafeHost), destination.Port);
if (this.IsMulticast)
{
UdpSocket socket = this.GetSendSocketUsingInterfaceIndex(message.Properties, out exceptionToBeThrown);
if (socket != null)
{
if (socket.AddressFamily == remoteEndPoint.AddressFamily)
{
socketList = new UdpSocket[] { socket };
}
else
{
exceptionToBeThrown = new InvalidOperationException(SR.RemoteAddressUnreachableDueToIPVersionMismatch(destination.DnsSafeHost));
}
}
}
else
{
UdpSocket socket = this.GetSendSocket(remoteEndPoint.Address, destination, out exceptionToBeThrown);
if (socket != null)
{
socketList = new UdpSocket[] { socket };
}
}
}
else
{
IPAddress[] remoteAddresses = DnsCache.Resolve(destination).AddressList;
if (this.IsMulticast)
{
UdpSocket socket = this.GetSendSocketUsingInterfaceIndex(message.Properties, out exceptionToBeThrown);
if (socket != null)
{
socketList = new UdpSocket[] { socket };
for (int i = 0; i < remoteAddresses.Length; i++)
{
if (remoteAddresses[i].AddressFamily == socket.AddressFamily)
{
remoteEndPoint = new IPEndPoint(remoteAddresses[i], destination.Port);
break;
}
}
if (remoteEndPoint == null)
{
// for multicast, we only listen on either IPv4 or IPv6 (not both).
// if we didn't find a matching remote endpoint, then it would indicate that
// the remote host didn't resolve to an address we can use...
exceptionToBeThrown = new InvalidOperationException(SR.RemoteAddressUnreachableDueToIPVersionMismatch(destination.DnsSafeHost));
}
}
}
else
{
bool useIPv4 = true;
bool useIPv6 = true;
for (int i = 0; i < remoteAddresses.Length; i++)
{
IPAddress address = remoteAddresses[i];
if (address.AddressFamily == AddressFamily.InterNetwork && useIPv4)
{
UdpSocket socket = this.GetSendSocket(address, destination, out exceptionToBeThrown);
if (socket == null)
{
if (this.State != CommunicationState.Opened)
{
// time to exit, the channel is closing down.
break;
}
else
{
// no matching socket on IPv4, so ignore future IPv4 addresses
// in the remoteAddresses list
useIPv4 = false;
}
}
else
{
remoteEndPoint = new IPEndPoint(address, destination.Port);
socketList = new UdpSocket[] { socket };
break;
}
}
else if (address.AddressFamily == AddressFamily.InterNetworkV6 && useIPv6)
{
UdpSocket socket = this.GetSendSocket(address, destination, out exceptionToBeThrown);
if (socket == null)
{
if (this.State != CommunicationState.Opened)
{
// time to exit, the channel is closing down.
break;
}
else
{
// no matching socket on IPv6, so ignore future IPv6 addresses
// in the remoteAddresses list
useIPv6 = false;
}
}
else
{
remoteEndPoint = new IPEndPoint(address, destination.Port);
socketList = new UdpSocket[] { socket };
break;
}
}
}
}
}
return(socketList);
}