WIP

aeron-client/src/main/c/uri/aeron_uri.h

@@ -66,6 +66,7 @@ aeron_uri_params_t;
 #define AERON_URI_ATS_KEY "ats"
 #define AERON_URI_SOCKET_SNDBUF_KEY "so-sndbuf"
 #define AERON_URI_SOCKET_RCVBUF_KEY "so-rcvbuf"
+#define AERON_URI_SOCKET_TOS_KEY "so-tos"
 #define AERON_URI_RECEIVER_WINDOW_KEY "rcv-wnd"
 #define AERON_URI_MEDIA_RCV_TIMESTAMP_OFFSET_KEY "media-rcv-ts-offset"
 #define AERON_URI_CHANNEL_RCV_TIMESTAMP_OFFSET_KEY "channel-rcv-ts-offset"

aeron-client/src/main/java/io/aeron/CommonContext.java

@@ -323,6 +323,11 @@ public static InferableBoolean parse(final String value)
      */
     public static final String SOCKET_RCVBUF_PARAM_NAME = "so-rcvbuf";
 
+    /**
+     * Parameter name for the underlying OS socket type of service (IP_TOS).
+     */
+    public static final String SOCKET_TOS_PARAM_NAME = "so-tos";
+
     /**
      * Parameter name for the congestion control's initial receiver window length.
      */

aeron-driver/src/main/java/io/aeron/driver/Configuration.java

@@ -275,11 +275,19 @@ public final class Configuration
      */
     public static final String SOCKET_MULTICAST_TTL_PROP_NAME = "aeron.socket.multicast.ttl";
 
+    /**
+     * Property name for IP_TOS setting on UDP sockets.
+     */
+    public static final String SOCKET_TOS_PROP_NAME = "aeron.socket.tos";
+
     /**
      * Multicast TTL value, 0 means use OS default.
      */
     public static final int SOCKET_MULTICAST_TTL_DEFAULT = 0;
 
+    // IP_TOS value, -1 means use OS defaults.
+    public static final int SOCKET_TOS_DEFAULT = -1;
+
     /**
      * Property name for linger timeout after draining on {@link Publication}s so they can respond to NAKs.
      */
@@ -1274,6 +1282,17 @@ public static int socketMulticastTtl()
         return getInteger(SOCKET_MULTICAST_TTL_PROP_NAME, SOCKET_MULTICAST_TTL_DEFAULT);
     }
 
+    /**
+     * IP_TOS setting to UDP sockets.
+     *
+     * @return IP_TOS setting on UDP sockets.
+     * @see #SOCKET_TOS_PROP_NAME
+     */
+    public static int socketToS()
+    {
+        return getInteger(SOCKET_TOS_PROP_NAME, SOCKET_TOS_DEFAULT);
+    }
+
     /**
      * Page size in bytes to align all files to. The file system must support the requested size.
      *

aeron-driver/src/main/java/io/aeron/driver/MediaDriver.java

@@ -470,6 +470,7 @@ public static final class Context extends CommonContext
         private int socketSndbufLength = Configuration.socketSndbufLength();
         private int socketRcvbufLength = Configuration.socketRcvbufLength();
         private int socketMulticastTtl = Configuration.socketMulticastTtl();
+        private int socketToS = Configuration.socketToS();
         private int mtuLength = Configuration.mtuLength();
         private int ipcMtuLength = Configuration.ipcMtuLength();
         private int filePageSize = Configuration.filePageSize();
@@ -1788,6 +1789,30 @@ public Context socketRcvbufLength(final int socketRcvbufLength)
             return this;
         }
 
+        /**
+         * The socket ToS which is the OS IP_TOS.
+         *
+         * @return the socket ToS.
+         * @see Configuration#SOCKET_TOS_PROP_NAME
+         */
+        public int socketToS()
+        {
+            return socketToS;
+        }
+
+        /**
+         * The socket ToS which is the OS IP_TOS.
+         *
+         * @param socketToS which is the OS IP_TOS.
+         * @return this for a fluent API.
+         * @see Configuration#SOCKET_TOS_PROP_NAME
+         */
+        public Context socketToS(final int socketToS)
+        {
+            this.socketToS = socketToS;
+            return this;
+        }
+
         /**
          * The TTL value to be used for multicast sockets.
          *
@@ -4040,6 +4065,7 @@ public String toString()
                 "\n    socketSndbufLength=" + socketSndbufLength +
                 "\n    socketRcvbufLength=" + socketRcvbufLength +
                 "\n    socketMulticastTtl=" + socketMulticastTtl +
+                    "\n    socketToS=" + socketToS +
                 "\n    mtuLength=" + mtuLength +
                 "\n    ipcMtuLength=" + ipcMtuLength +
                 "\n    filePageSize=" + filePageSize +

aeron-driver/src/main/java/io/aeron/driver/media/ReceiveDestinationTransport.java

@@ -39,11 +39,11 @@ abstract class ReceiveDestinationTransportLhsPadding extends UdpChannelTransport
         final InetSocketAddress connectAddress,
         final MediaDriver.Context context,
         final int socketRcvbufLength,
-        final int socketSndbufLength)
+        final int socketSndbufLength, final int socketToS)
     {
         super(
             udpChannel, endPointAddress, bindAddress, connectAddress, context.receiverPortManager(),
-            context, socketRcvbufLength, socketSndbufLength);
+            context, socketRcvbufLength, socketSndbufLength, socketToS);
     }
 }
 
@@ -58,10 +58,13 @@ abstract class ReceiveDestinationTransportHotFields extends ReceiveDestinationTr
         final InetSocketAddress connectAddress,
         final MediaDriver.Context context,
         final int socketRcvbufLength,
-        final int socketSndbufLength)
+        final int socketSndbufLength,
+        final int socketToS)
     {
         super(
-            udpChannel, endPointAddress, bindAddress, connectAddress, context, socketRcvbufLength, socketSndbufLength);
+            udpChannel, endPointAddress, bindAddress, connectAddress, context, socketRcvbufLength,
+            socketSndbufLength, socketToS);
+
     }
 }
 
@@ -79,10 +82,12 @@ abstract class ReceiveDestinationTransportRhsPadding extends ReceiveDestinationT
         final InetSocketAddress connectAddress,
         final MediaDriver.Context context,
         final int socketRcvbufLength,
-        final int socketSndbufLength)
+        final int socketSndbufLength,
+        final int socketToS)
     {
         super(
-            udpChannel, endPointAddress, bindAddress, connectAddress, context, socketRcvbufLength, socketSndbufLength);
+            udpChannel, endPointAddress, bindAddress, connectAddress, context, socketRcvbufLength,
+            socketSndbufLength, socketToS);
     }
 }
 
@@ -115,7 +120,8 @@ public ReceiveDestinationTransport(
             null,
             context,
             receiveChannelEndpoint.socketRcvbufLength(),
-            receiveChannelEndpoint.socketSndbufLength());
+            receiveChannelEndpoint.socketSndbufLength(),
+            receiveChannelEndpoint.socketToS());
 
         this.timeOfLastActivityNs = context.receiverCachedNanoClock().nanoTime();
         this.currentControlAddress = udpChannel.hasExplicitControl() ? udpChannel.localControl() : null;

aeron-driver/src/main/java/io/aeron/driver/media/UdpChannel.java

@@ -28,6 +28,7 @@
 import java.util.concurrent.atomic.AtomicInteger;
 
 import static io.aeron.CommonContext.*;
+import static io.aeron.driver.Configuration.SOCKET_TOS_DEFAULT;
 import static io.aeron.driver.media.NetworkUtil.*;
 import static java.lang.System.lineSeparator;
 import static java.net.InetAddress.getByAddress;
@@ -58,6 +59,7 @@ public final class UdpChannel
     private final int multicastTtl;
     private final int socketRcvbufLength;
     private final int socketSndbufLength;
+    private final int socketToS;
     private final int receiverWindowLength;
     private final long tag;
     private final InetSocketAddress remoteData;
@@ -94,6 +96,7 @@ private UdpChannel(final Context context)
         channelUri = context.channelUri;
         socketRcvbufLength = context.socketRcvbufLength;
         socketSndbufLength = context.socketSndbufLength;
+        socketToS = context.socketToS;
         receiverWindowLength = context.receiverWindowLength;
         channelReceiveTimestampOffset = context.channelReceiveTimestampOffset;
         channelSendTimestampOffset = context.channelSendTimestampOffset;
@@ -162,6 +165,8 @@ public static UdpChannel parse(
             final boolean hasNoDistinguishingCharacteristic =
                 null == endpointAddress && null == controlAddress && null == tagIdStr;
 
+            final int socketToS = parseSocketToS(channelUri);
+
             if (ControlMode.DYNAMIC == controlMode && null == controlAddress)
             {
                 throw new IllegalArgumentException(
@@ -186,6 +191,7 @@ public static UdpChannel parse(
                 throw new UnknownHostException("could not resolve control address: " + controlAddress);
             }
 
+
             boolean hasExplicitEndpoint = true;
             if (null == endpointAddress)
             {
@@ -206,7 +212,8 @@ public static UdpChannel parse(
                 .hasNoDistinguishingCharacteristic(hasNoDistinguishingCharacteristic)
                 .socketRcvbufLength(socketRcvbufLength)
                 .socketSndbufLength(socketSndbufLength)
-                .receiverWindowLength(receiverWindowLength);
+                .receiverWindowLength(receiverWindowLength)
+                .socketToS(socketToS);
 
             if (null != tagIdStr)
             {
@@ -367,6 +374,31 @@ public static int parseBufferLength(final ChannelUri channelUri, final String pa
         return socketBufferLength;
     }
 
+    /**
+     * Parses the IP_TOS for a given URI paramName. The range of the IP_TOS is 0 <= x <= 255.
+     * <p/>
+     * If the parameter isn't set,  <code>SOCKET_TOS_DEFAULT</code> is returned.
+     *
+     * @param channelUri to get the value from.
+     * @return the parsed IP_TOS.
+     */
+    public static int parseSocketToS(final ChannelUri channelUri)
+    {
+        int tos = SOCKET_TOS_DEFAULT;
+
+        final String paramValue = channelUri.get(SOCKET_TOS_PARAM_NAME);
+        if (null != paramValue)
+        {
+            tos = Integer.parseInt(paramValue);
+            if (tos < 0 || tos > 255)
+            {
+                throw new IllegalArgumentException("Invalid " + SOCKET_TOS_PARAM_NAME + " value: " + paramValue);
+            }
+        }
+
+        return tos;
+    }
+
     /**
      * Parse the control mode from the channel URI. If the value is null or unknown then {@link ControlMode#NONE} will
      * be used.
@@ -709,6 +741,27 @@ public int socketSndbufLengthOrDefault(final int defaultValue)
         return 0 != socketSndbufLength ? socketSndbufLength : defaultValue;
     }
 
+    /**
+     * Gets the socket type of service (IP_TOS).
+     *
+     * @return socket type of service or -1 if not specified.
+     */
+    public int socketToS()
+    {
+        return socketToS;
+    }
+
+    /**
+     * Get the socket type of service (IP_TOS).
+     *
+     * @param defaultValue to be used if the UdpChannel's value is 0 (unspecified).
+     * @return socket type of service or defaultValue if not specified.
+     */
+    public int socketToSOrDefault(final int defaultValue)
+    {
+        return SOCKET_TOS_DEFAULT != socketToS ? socketToS : defaultValue;
+    }
+
     /**
      * Get the receiver window length used as the initial window length for congestion control.
      *
@@ -1070,6 +1123,7 @@ static final class Context
         boolean hasNoDistinguishingCharacteristic = false;
         int socketRcvbufLength = 0;
         int socketSndbufLength = 0;
+        int socketToS;
         int receiverWindowLength = 0;
         int multicastTtl;
         long tagId;
@@ -1209,6 +1263,12 @@ Context socketSndbufLength(final int socketSndbufLength)
             return this;
         }
 
+        Context socketToS(final int socketToS)
+        {
+            this.socketToS = socketToS;
+            return this;
+        }
+
         Context receiverWindowLength(final int receiverWindowLength)
         {
             this.receiverWindowLength = receiverWindowLength;

aeron-driver/src/main/java/io/aeron/driver/media/UdpChannelTransport.java

@@ -34,6 +34,7 @@
 import java.nio.channels.DatagramChannel;
 import java.nio.channels.SelectionKey;
 
+import static io.aeron.driver.Configuration.SOCKET_TOS_DEFAULT;
 import static io.aeron.logbuffer.FrameDescriptor.frameVersion;
 import static java.net.StandardSocketOptions.SO_RCVBUF;
 import static java.net.StandardSocketOptions.SO_SNDBUF;
@@ -73,6 +74,8 @@ public abstract class UdpChannelTransport implements AutoCloseable
      */
     protected InetSocketAddress connectAddress;
 
+
+
     /**
      * To be used when polling the transport.
      */
@@ -91,6 +94,7 @@ public abstract class UdpChannelTransport implements AutoCloseable
     private int multicastTtl = 0;
     private final int socketSndbufLength;
     private final int socketRcvbufLength;
+    private final int socketToS;
 
     /**
      * Construct transport for a given channel.
@@ -103,6 +107,7 @@ public abstract class UdpChannelTransport implements AutoCloseable
      * @param portManager        for port binding.
      * @param socketRcvbufLength set SO_RCVBUF for socket, 0 for OS default.
      * @param socketSndbufLength set SO_SNDBUF for socket, 0 for OS default.
+     * @param socketToS          set IP_TOS for socket, -1 for OS default.
      */
     protected UdpChannelTransport(
         final UdpChannel udpChannel,
@@ -112,7 +117,8 @@ protected UdpChannelTransport(
         final PortManager portManager,
         final MediaDriver.Context context,
         final int socketRcvbufLength,
-        final int socketSndbufLength)
+        final int socketSndbufLength,
+        final int socketToS)
     {
         this.context = context;
         this.udpChannel = udpChannel;
@@ -124,6 +130,7 @@ protected UdpChannelTransport(
         this.invalidPackets = context.systemCounters().get(SystemCounterDescriptor.INVALID_PACKETS);
         this.socketRcvbufLength = socketRcvbufLength;
         this.socketSndbufLength = socketSndbufLength;
+        this.socketToS = socketToS;
     }
 
     /**
@@ -152,7 +159,8 @@ protected UdpChannelTransport(
             portManager,
             context,
             udpChannel.socketRcvbufLengthOrDefault(context.socketRcvbufLength()),
-            udpChannel.socketSndbufLengthOrDefault(context.socketSndbufLength()));
+            udpChannel.socketSndbufLengthOrDefault(context.socketSndbufLength()),
+            udpChannel.socketToSOrDefault(context.socketToS()));
     }
 
     /**
@@ -225,6 +233,11 @@ else if (context.socketMulticastTtl() != 0)
                 receiveDatagramChannel.setOption(SO_RCVBUF, socketRcvbufLength());
             }
 
+            if (SOCKET_TOS_DEFAULT != socketToS)
+            {
+                receiveDatagramChannel.socket().setTrafficClass(socketToS);
+            }
+
             sendDatagramChannel.configureBlocking(false);
             receiveDatagramChannel.configureBlocking(false);
         }
@@ -500,4 +513,15 @@ public int socketRcvbufLength()
     {
         return socketRcvbufLength;
     }
+
+
+    /**
+     * Gets the configured OS type of service (IP_TOS) for the endpoint's socket.
+     *
+     * @return OS socket type of service or -1 if using OS default.
+     */
+    public int socketToS()
+    {
+        return socketToS;
+    }
 }

aeron-driver/src/test/java/io/aeron/driver/UdpChannelTest.java

@@ -502,6 +502,16 @@ void shouldParseReceiverWindow()
         assertEquals(8192, udpChannelWithBufferSizes.receiverWindowLength());
     }
 
+    @Test
+    void shouldParseToS()
+    {
+        final UdpChannel udpChannelWithToS = UdpChannel.parse("aeron:udp?endpoint=127.0.0.1:9999|so-tos=10");
+        assertEquals(10, udpChannelWithToS.socketToS());
+
+        final UdpChannel udpChannelWithoutToS = UdpChannel.parse("aeron:udp?endpoint=127.0.0.1:9999");
+        assertEquals(-1, udpChannelWithoutToS.socketToS());
+    }
+
     @Test
     void shouldParseChannelSendAndReceiveTimestampOffsets()
     {