src/java.base/share/classes/sun/net/sdp/SdpSupport.java

/*
 * Copyright (c) 2010, 2023, 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
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package sun.net.sdp;

import java.io.IOException;
import java.io.FileDescriptor;

import jdk.internal.access.SharedSecrets;
import jdk.internal.access.JavaIOFileDescriptorAccess;
import jdk.internal.util.OperatingSystem;


/**
 * This class defines methods for creating SDP sockets or "converting" existing
 * file descriptors, referencing (unbound) TCP sockets, to SDP.
 */

public final class SdpSupport {
    private static final boolean isSupported = OperatingSystem.isLinux();
    private static final JavaIOFileDescriptorAccess fdAccess =
        SharedSecrets.getJavaIOFileDescriptorAccess();

    private SdpSupport() { }

    /**
     * Creates a SDP socket, returning file descriptor referencing the socket.
     */
    public static FileDescriptor createSocket() throws IOException {
        if (!isSupported)
            throw new UnsupportedOperationException("SDP not supported on this platform");
        int fdVal = create0();
        FileDescriptor fd = new FileDescriptor();
        fdAccess.set(fd, fdVal);
        return fd;
    }

    /**
     * Converts an existing file descriptor, that references an unbound TCP socket,
     * to SDP.
     */
    public static void convertSocket(FileDescriptor fd) throws IOException {
        if (!isSupported)
            throw new UnsupportedOperationException("SDP not supported on this platform");
        int fdVal = fdAccess.get(fd);
        convert0(fdVal);
    }

    private static native int create0() throws IOException;

    private static native void convert0(int fd) throws IOException;

    static {
        jdk.internal.loader.BootLoader.loadLibrary("net");
    }
}