--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.base/share/classes/sun/net/ext/RdmaSocketOptions.java	Sat Jan 26 14:02:35 2019 +0000
@@ -0,0 +1,109 @@
+/*
+ * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Oracle designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Oracle in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+
+package sun.net.ext;
+
+import java.io.FileDescriptor;
+import java.net.SocketException;
+import java.net.SocketOption;
+import java.util.Collections;
+import java.util.Set;
+
+/**
+ * Defines the infrastructure to support RDMA socket options.
+ *
+ * RDMA socket options are accessed through the jdk.net API, which is in
+ * the jdk.net module.
+ */
+public abstract class RdmaSocketOptions {
+
+    private final Set<SocketOption<?>> options;
+
+    /** Tells whether or not the option is supported. */
+    public final boolean isOptionSupported(SocketOption<?> option) {
+        return options().contains(option);
+    }
+
+    /** Return the, possibly empty, set of RDMA socket options available. */
+    public final Set<SocketOption<?>> options() { return options; }
+
+    /** Sets the value of a socket option, for the given socket. */
+    public abstract void setOption(FileDescriptor fd, SocketOption<?> option,
+            Object value) throws SocketException;
+
+    /** Returns the value of a socket option, for the given socket. */
+    public abstract Object getOption(FileDescriptor fd, SocketOption<?> option)
+            throws SocketException;
+
+    protected RdmaSocketOptions(Set<SocketOption<?>> options) {
+        this.options = options;
+    }
+
+    private static volatile RdmaSocketOptions instance;
+
+    public static final RdmaSocketOptions getInstance() { return instance; }
+
+    /** Registers support for RDMA socket options. Invoked by the jdk.net module. */
+    public static final void register(RdmaSocketOptions rdmaOptions) {
+        if (instance != null)
+            throw new InternalError("Attempting to reregister RDMA options");
+
+        instance = rdmaOptions;
+    }
+
+    static {
+        try {
+            // If the class is present, it will be initialized which
+            // triggers registration of the RDMA socket options.
+            Class<?> c = Class.forName("jdk.net.RdmaSocketOptions");
+        } catch (ClassNotFoundException e) {
+            // the jdk.net module is not present => no RDMA socket options
+            instance = new NoRdmaSocketOptions();
+        }
+    }
+
+    static final class NoRdmaSocketOptions extends RdmaSocketOptions {
+
+        NoRdmaSocketOptions() {
+            super(Collections.<SocketOption<?>>emptySet());
+        }
+
+        @Override
+        public void setOption(FileDescriptor fd, SocketOption<?> option,
+                Object value) throws SocketException
+        {
+            throw new UnsupportedOperationException(
+                    "no RDMA options: " + option.name());
+        }
+
+        @Override
+        public Object getOption(FileDescriptor fd, SocketOption<?> option)
+            throws SocketException
+        {
+            throw new UnsupportedOperationException(
+                    "no RDMA options: " + option.name());
+        }
+    }
+}