1 files changed, 113 insertions, 0 deletions
diff --git a/Emby.Common.Implementations/Net/SocketFactory.cs b/Emby.Common.Implementations/Net/SocketFactory.cs
new file mode 100644
index 000000000..3a2cea12a
--- /dev/null
+++ b/Emby.Common.Implementations/Net/SocketFactory.cs
@@ -0,0 +1,113 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Net;
+using System.Net.Sockets;
+using System.Threading.Tasks;
+using MediaBrowser.Model.Net;
+
+namespace Emby.Common.Implementations.Net
+{
+    public class SocketFactory : ISocketFactory
+    {
+        // THIS IS A LINKED FILE - SHARED AMONGST MULTIPLE PLATFORMS	
+        // Be careful to check any changes compile and work for all platform projects it is shared in.
+
+        // Not entirely happy with this. Would have liked to have done something more generic/reusable,
+        // but that wasn't really the point so kept to YAGNI principal for now, even if the 
+        // interfaces are a bit ugly, specific and make assumptions.
+
+        /// <summary>
+        /// Used by RSSDP components to create implementations of the <see cref="IUdpSocket"/> interface, to perform platform agnostic socket communications.
+        /// </summary>
+        private IPAddress _LocalIP;
+
+        /// <summary>
+        /// Default constructor.
+        /// </summary>
+        /// <param name="localIP">A string containing the IP address of the local network adapter to bind sockets to. Null or empty string will use <see cref="IPAddress.Any"/>.</param>
+        public SocketFactory(string localIP)
+        {
+            if (String.IsNullOrEmpty(localIP))
+                _LocalIP = IPAddress.Any;
+            else
+                _LocalIP = IPAddress.Parse(localIP);
+        }
+
+        #region ISocketFactory Members
+
+        /// <summary>
+        /// Creates a new UDP socket that is a member of the SSDP multicast local admin group and binds it to the specified local port.
+        /// </summary>
+        /// <param name="localPort">An integer specifying the local port to bind the socket to.</param>
+        /// <returns>An implementation of the <see cref="IUdpSocket"/> interface used by RSSDP components to perform socket operations.</returns>
+        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Reliability", "CA2000:Dispose objects before losing scope", Justification = "The purpose of this method is to create and returns a disposable result, it is up to the caller to dispose it when they are done with it.")]
+        public IUdpSocket CreateUdpSocket(int localPort)
+        {
+            if (localPort < 0) throw new ArgumentException("localPort cannot be less than zero.", "localPort");
+
+            var retVal = new Socket(System.Net.Sockets.AddressFamily.InterNetwork, System.Net.Sockets.SocketType.Dgram, System.Net.Sockets.ProtocolType.Udp);
+            try
+            {
+                retVal.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
+                retVal.SetSocketOption(SocketOptionLevel.IP, SocketOptionName.MulticastTimeToLive, 4);
+                retVal.SetSocketOption(SocketOptionLevel.IP, SocketOptionName.AddMembership, new MulticastOption(IPAddress.Parse("239.255.255.250"), _LocalIP));
+                return new UdpSocket(retVal, localPort, _LocalIP.ToString());
+            }
+            catch
+            {
+                if (retVal != null)
+                    retVal.Dispose();
+
+                throw;
+            }
+        }
+
+        /// <summary>
+        /// Creates a new UDP socket that is a member of the specified multicast IP address, and binds it to the specified local port.
+        /// </summary>
+        /// <param name="ipAddress">The multicast IP address to make the socket a member of.</param>
+        /// <param name="multicastTimeToLive">The multicast time to live value for the socket.</param>
+        /// <param name="localPort">The number of the local port to bind to.</param>
+        /// <returns></returns>
+        [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Naming", "CA1704:IdentifiersShouldBeSpelledCorrectly", MessageId = "ip"), System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Reliability", "CA2000:Dispose objects before losing scope", Justification = "The purpose of this method is to create and returns a disposable result, it is up to the caller to dispose it when they are done with it.")]
+        public IUdpSocket CreateUdpMulticastSocket(string ipAddress, int multicastTimeToLive, int localPort)
+        {
+            if (ipAddress == null) throw new ArgumentNullException("ipAddress");
+            if (ipAddress.Length == 0) throw new ArgumentException("ipAddress cannot be an empty string.", "ipAddress");
+            if (multicastTimeToLive <= 0) throw new ArgumentException("multicastTimeToLive cannot be zero or less.", "multicastTimeToLive");
+            if (localPort < 0) throw new ArgumentException("localPort cannot be less than zero.", "localPort");
+
+            var retVal = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
+
+            try
+            {
+#if NETSTANDARD1_3
+				// The ExclusiveAddressUse socket option is a Windows-specific option that, when set to "true," tells Windows not to allow another socket to use the same local address as this socket
+				// See https://github.com/dotnet/corefx/pull/11509 for more details
+				if (System.Runtime.InteropServices.RuntimeInformation.IsOSPlatform(System.Runtime.InteropServices.OSPlatform.Windows))
+				{
+					retVal.ExclusiveAddressUse = false;
+				}
+#else
+                retVal.ExclusiveAddressUse = false;
+#endif
+                retVal.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
+                retVal.SetSocketOption(SocketOptionLevel.IP, SocketOptionName.MulticastTimeToLive, multicastTimeToLive);
+                retVal.SetSocketOption(SocketOptionLevel.IP, SocketOptionName.AddMembership, new MulticastOption(IPAddress.Parse(ipAddress), _LocalIP));
+                retVal.MulticastLoopback = true;
+
+                return new UdpSocket(retVal, localPort, _LocalIP.ToString());
+            }
+            catch
+            {
+                if (retVal != null)
+                    retVal.Dispose();
+
+                throw;
+            }
+        }
+
+        #endregion
+    }
+}