8234805: (dc) Remove JNI upcall from DatagramChannel.receive implementation
authoralanb
Sat, 30 Nov 2019 16:21:19 +0000
changeset 59329 289000934908
parent 59328 f280911d3427
child 59330 5b96c12f909d
8234805: (dc) Remove JNI upcall from DatagramChannel.receive implementation Reviewed-by: dfuchs, chegar
src/java.base/share/classes/sun/nio/ch/DatagramChannelImpl.java
src/java.base/share/classes/sun/nio/ch/NativeSocketAddress.java
src/java.base/share/native/libnio/ch/NativeSocketAddress.c
src/java.base/unix/native/libnio/ch/DatagramChannelImpl.c
src/java.base/windows/native/libnio/ch/DatagramChannelImpl.c
test/jdk/java/nio/channels/DatagramChannel/ManySenders.java
--- a/src/java.base/share/classes/sun/nio/ch/DatagramChannelImpl.java	Fri Nov 29 14:11:50 2019 -0800
+++ b/src/java.base/share/classes/sun/nio/ch/DatagramChannelImpl.java	Sat Nov 30 16:21:19 2019 +0000
@@ -90,12 +90,12 @@
     // Our file descriptor
     private final FileDescriptor fd;
     private final int fdVal;
-    private final Cleanable cleaner;
 
-    // Cached InetAddress and port for unconnected DatagramChannels
-    // used by receive0
-    private InetAddress cachedSenderInetAddress;
-    private int cachedSenderPort;
+    // Native buffer for socket address used by receive0, protected by readLock
+    private final NativeSocketAddress socketAddress;
+
+    // Cleaner to close file descriptor and free native socket address
+    private final Cleanable cleaner;
 
     // Lock held by current reading or connecting thread
     private final ReentrantLock readLock = new ReentrantLock();
@@ -154,6 +154,9 @@
         throws IOException
     {
         super(sp);
+
+        this.socketAddress = new NativeSocketAddress();
+
         ResourceManager.beforeUdpCreate();
         try {
             this.family = Net.isIPv6Available()
@@ -163,9 +166,12 @@
             this.fdVal = IOUtil.fdVal(fd);
         } catch (IOException ioe) {
             ResourceManager.afterUdpClose();
+            socketAddress.free();
             throw ioe;
         }
-        this.cleaner = CleanerFactory.cleaner().register(this, closerFor(fd));
+
+        Runnable releaser = releaserFor(fd, socketAddress);
+        this.cleaner = CleanerFactory.cleaner().register(this, releaser);
     }
 
     public DatagramChannelImpl(SelectorProvider sp, ProtocolFamily family)
@@ -183,6 +189,8 @@
             }
         }
 
+        this.socketAddress = new NativeSocketAddress();
+
         ResourceManager.beforeUdpCreate();
         try {
             this.family = family;
@@ -190,9 +198,12 @@
             this.fdVal = IOUtil.fdVal(fd);
         } catch (IOException ioe) {
             ResourceManager.afterUdpClose();
+            socketAddress.free();
             throw ioe;
         }
-        this.cleaner = CleanerFactory.cleaner().register(this, closerFor(fd));
+
+        Runnable releaser = releaserFor(fd, socketAddress);
+        this.cleaner = CleanerFactory.cleaner().register(this, releaser);
     }
 
     public DatagramChannelImpl(SelectorProvider sp, FileDescriptor fd)
@@ -200,6 +211,13 @@
     {
         super(sp);
 
+        try {
+            this.socketAddress = new NativeSocketAddress();
+        } catch (OutOfMemoryError e) {
+            nd.close(fd);
+            throw e;
+        }
+
         // increment UDP count to match decrement when closing
         ResourceManager.beforeUdpCreate();
 
@@ -208,7 +226,10 @@
                 : StandardProtocolFamily.INET;
         this.fd = fd;
         this.fdVal = IOUtil.fdVal(fd);
-        this.cleaner = CleanerFactory.cleaner().register(this, closerFor(fd));
+
+        Runnable releaser = releaserFor(fd, socketAddress);
+        this.cleaner = CleanerFactory.cleaner().register(this, releaser);
+
         synchronized (stateLock) {
             this.localAddress = Net.localAddress(fd);
         }
@@ -450,8 +471,6 @@
         }
     }
 
-    private SocketAddress sender;       // Set by receive0 (## ugh)
-
     @Override
     public SocketAddress receive(ByteBuffer dst) throws IOException {
         if (dst.isReadOnly())
@@ -459,33 +478,31 @@
         readLock.lock();
         try {
             boolean blocking = isBlocking();
-            boolean completed = false;
-            int n = 0;
+            SocketAddress sender = null;
             try {
                 SocketAddress remote = beginRead(blocking, false);
                 boolean connected = (remote != null);
                 SecurityManager sm = System.getSecurityManager();
-
                 if (connected || (sm == null)) {
                     // connected or no security manager
-                    n = receive(dst, connected);
+                    int n = receive(dst, connected);
                     if (blocking) {
                         while (IOStatus.okayToRetry(n) && isOpen()) {
                             park(Net.POLLIN);
                             n = receive(dst, connected);
                         }
                     }
+                    if (n >= 0) {
+                        // sender address is in socket address buffer
+                        sender = socketAddress.toInetSocketAddress();
+                    }
                 } else {
                     // security manager and unconnected
-                    n = untrustedReceive(dst);
+                    sender = untrustedReceive(dst);
                 }
-                if (n == IOStatus.UNAVAILABLE)
-                    return null;
-                completed = (n > 0) || (n == 0 && isOpen());
                 return sender;
             } finally {
-                endRead(blocking, completed);
-                assert IOStatus.check(n);
+                endRead(blocking, (sender != null));
             }
         } finally {
             readLock.unlock();
@@ -498,10 +515,8 @@
      * into a buffer that is not accessible to the user. The datagram is copied
      * into the user's buffer when the sender address is accepted by the security
      * manager.
-     *
-     * @return the size of the datagram or IOStatus.UNAVAILABLE
      */
-    private int untrustedReceive(ByteBuffer dst) throws IOException {
+    private SocketAddress untrustedReceive(ByteBuffer dst) throws IOException {
         SecurityManager sm = System.getSecurityManager();
         assert readLock.isHeldByCurrentThread()
                 && sm != null && remoteAddress == null;
@@ -516,18 +531,21 @@
                         park(Net.POLLIN);
                         n = receive(bb, false);
                     }
-                } else if (n == IOStatus.UNAVAILABLE) {
-                    return n;
                 }
-                InetSocketAddress isa = (InetSocketAddress) sender;
-                try {
-                    sm.checkAccept(isa.getAddress().getHostAddress(), isa.getPort());
-                    bb.flip();
-                    dst.put(bb);
-                    return n;
-                } catch (SecurityException se) {
-                    // ignore datagram
-                    bb.clear();
+                if (n >= 0) {
+                    // sender address is in socket address buffer
+                    InetSocketAddress isa = socketAddress.toInetSocketAddress();
+                    try {
+                        sm.checkAccept(isa.getAddress().getHostAddress(), isa.getPort());
+                        bb.flip();
+                        dst.put(bb);
+                        return isa;
+                    } catch (SecurityException se) {
+                        // ignore datagram
+                        bb.clear();
+                    }
+                } else {
+                    return null;
                 }
             }
         } finally {
@@ -584,21 +602,22 @@
         throws IOException
     {
         assert readLock.isHeldByCurrentThread() && isBlocking();
-        boolean completed = false;
-        int n = 0;
+        SocketAddress sender = null;
         try {
             SocketAddress remote = beginRead(true, false);
             boolean connected = (remote != null);
-            n = receive(dst, connected);
-            while (n == IOStatus.UNAVAILABLE && isOpen()) {
+            int n = receive(dst, connected);
+            while (IOStatus.okayToRetry(n) && isOpen()) {
                 park(Net.POLLIN);
                 n = receive(dst, connected);
             }
-            completed = (n > 0) || (n == 0 && isOpen());
+            if (n >= 0) {
+                // sender address is in socket address buffer
+                sender = socketAddress.toInetSocketAddress();
+            }
             return sender;
         } finally {
-            endRead(true, completed);
-            assert IOStatus.check(n);
+            endRead(true, (sender != null));
         }
     }
 
@@ -611,8 +630,7 @@
         throws IOException
     {
         assert readLock.isHeldByCurrentThread() && isBlocking();
-        boolean completed = false;
-        int n = 0;
+        SocketAddress sender = null;
         try {
             SocketAddress remote = beginRead(true, false);
             boolean connected = (remote != null);
@@ -621,7 +639,7 @@
             lockedConfigureBlocking(false);
             try {
                 long startNanos = System.nanoTime();
-                n = receive(dst, connected);
+                int n = receive(dst, connected);
                 while (n == IOStatus.UNAVAILABLE && isOpen()) {
                     long remainingNanos = nanos - (System.nanoTime() - startNanos);
                     if (remainingNanos <= 0) {
@@ -630,16 +648,17 @@
                     park(Net.POLLIN, remainingNanos);
                     n = receive(dst, connected);
                 }
-                completed = (n > 0) || (n == 0 && isOpen());
+                if (n >= 0) {
+                    // sender address is in socket address buffer
+                    sender = socketAddress.toInetSocketAddress();
+                }
                 return sender;
             } finally {
                 // restore socket to blocking mode (if channel is open)
                 tryLockedConfigureBlocking(true);
             }
-
         } finally {
-            endRead(true, completed);
-            assert IOStatus.check(n);
+            endRead(true, (sender != null));
         }
     }
 
@@ -671,7 +690,10 @@
                                         boolean connected)
         throws IOException
     {
-        int n = receive0(fd, ((DirectBuffer)bb).address() + pos, rem, connected);
+        int n = receive0(fd,
+                         ((DirectBuffer)bb).address() + pos, rem,
+                         socketAddress.address(),
+                         connected);
         if (n > 0)
             bb.position(pos + n);
         return n;
@@ -1709,38 +1731,37 @@
     }
 
     /**
-     * Returns an action to close the given file descriptor.
+     * Returns an action to release a the given file descriptor and free the
+     * given native socket address.
      */
-    private static Runnable closerFor(FileDescriptor fd) {
+    private static Runnable releaserFor(FileDescriptor fd, NativeSocketAddress sa) {
         return () -> {
             try {
                 nd.close(fd);
             } catch (IOException ioe) {
                 throw new UncheckedIOException(ioe);
             } finally {
-                // decrement
+                // decrement socket count and release memory
                 ResourceManager.afterUdpClose();
+                sa.free();
             }
         };
     }
 
     // -- Native methods --
 
-    private static native void initIDs();
-
     private static native void disconnect0(FileDescriptor fd, boolean isIPv6)
         throws IOException;
 
-    private native int receive0(FileDescriptor fd, long address, int len,
-                                boolean connected)
+    private static native int receive0(FileDescriptor fd, long address, int len,
+                                       long senderAddress, boolean connected)
         throws IOException;
 
-    private native int send0(boolean preferIPv6, FileDescriptor fd, long address,
-                             int len, InetAddress addr, int port)
+    private static native int send0(boolean preferIPv6, FileDescriptor fd,
+                                    long address, int len, InetAddress addr, int port)
         throws IOException;
 
     static {
         IOUtil.load();
-        initIDs();
     }
 }
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.base/share/classes/sun/nio/ch/NativeSocketAddress.java	Sat Nov 30 16:21:19 2019 +0000
@@ -0,0 +1,213 @@
+/*
+ * Copyright (c) 2019, 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.nio.ch;
+
+import java.net.Inet6Address;
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
+import java.net.SocketException;
+import java.net.UnknownHostException;
+
+import jdk.internal.misc.Unsafe;
+import jdk.internal.util.ArraysSupport;
+
+/**
+ * A native socket address that is the union of struct sockaddr, struct sockaddr_in,
+ * and struct sockaddr_in6.
+ *
+ * This class is not thread safe.
+ */
+class NativeSocketAddress {
+    private static final Unsafe UNSAFE = Unsafe.getUnsafe();
+    private static final long ARRAY_BASE_OFFSET = UNSAFE.arrayBaseOffset(byte[].class);
+
+    private static final int AF_INET  = AFINET();
+    private static final int AF_INET6 = AFINET6();
+
+    private static final int SIZEOF_SOCKETADDRESS = sizeofSOCKETADDRESS();
+    private static final int SIZEOF_FAMILY        = sizeofFamily();
+    private static final int OFFSET_FAMILY        = offsetFamily();
+    private static final int OFFSET_SIN4_PORT     = offsetSin4Port();
+    private static final int OFFSET_SIN4_ADDR     = offsetSin4Addr();
+    private static final int OFFSET_SIN6_PORT     = offsetSin6Port();
+    private static final int OFFSET_SIN6_ADDR     = offsetSin6Addr();
+    private static final int OFFSET_SIN6_SCOPE_ID = offsetSin6ScopeId();
+
+    // SOCKETADDRESS
+    private final long address;
+
+    // cached copy of SOCKETADDRESS and the corresponding InetSocketAddress
+    private final long cachedSocketAddress;
+    private InetSocketAddress cachedInetSocketAddress;
+
+    NativeSocketAddress() {
+        // allocate 2 * SOCKETADDRESS
+        int size = SIZEOF_SOCKETADDRESS << 1;
+        long base = UNSAFE.allocateMemory(size);
+        UNSAFE.setMemory(base, size, (byte) 0);
+
+        this.address = base;
+        this.cachedSocketAddress = base + SIZEOF_SOCKETADDRESS;
+    }
+
+    long address() {
+        return address;
+    }
+
+    void free() {
+        UNSAFE.freeMemory(address);
+    }
+
+    /**
+     * Return an InetSocketAddress to represent the socket address in this buffer.
+     * @throws SocketException if the socket address is not AF_INET or AF_INET6
+     */
+    InetSocketAddress toInetSocketAddress() throws SocketException {
+        // return cached InetSocketAddress if the SOCKETADDRESS bytes match
+        if (cachedInetSocketAddress != null && mismatch() < 0) {
+            return cachedInetSocketAddress;
+        }
+
+        // decode SOCKETADDRESS to InetSocketAddress
+        int family = family();
+        if (family != AF_INET && family != AF_INET6)
+            throw new SocketException("Socket family not recognized");
+        var isa = new InetSocketAddress(address(family), port(family));
+
+        // copy SOCKETADDRESS and InetSocketAddress
+        UNSAFE.copyMemory(null, address, null, cachedSocketAddress, SIZEOF_SOCKETADDRESS);
+        this.cachedInetSocketAddress = isa;
+        return isa;
+    }
+
+    /**
+     * Find a mismatch between the SOCKETADDRESS structures stored at address
+     * and cachedSocketAddress.
+     * @return the byte offset of the first mismatch or -1 if no mismatch
+     */
+    private int mismatch() {
+        int i = ArraysSupport.vectorizedMismatch(null,
+                address,
+                null,
+                cachedSocketAddress,
+                SIZEOF_SOCKETADDRESS,
+                ArraysSupport.LOG2_ARRAY_BYTE_INDEX_SCALE);
+        if (i >= 0)
+            return i;
+        i = SIZEOF_SOCKETADDRESS - ~i;
+        for (; i < SIZEOF_SOCKETADDRESS; i++) {
+            if (UNSAFE.getByte(address + i) != UNSAFE.getByte(cachedSocketAddress + i)) {
+                return i;
+            }
+        }
+        return -1;
+    }
+
+    @Override
+    public String toString() {
+        int family = family();
+        if (family == AF_INET || family == AF_INET6) {
+            return ((family == AF_INET) ? "AF_INET" : "AF_INET6")
+                    + ", address=" + address(family) + ", port=" + port(family);
+        } else {
+            return "<unknown>";
+        }
+    }
+
+    /**
+     * Return the value of the sa_family field.
+     */
+    private int family() {
+        if (SIZEOF_FAMILY == 1) {
+            return UNSAFE.getByte(address + OFFSET_FAMILY);
+        } else if (SIZEOF_FAMILY == 2) {
+            return UNSAFE.getShort(address + OFFSET_FAMILY);
+        } else {
+            throw new InternalError();
+        }
+    }
+
+    /**
+     * Return the value of the sin4_port or sin6_port field. These fields are
+     * stored in network order.
+     */
+    private int port(int family) {
+        byte b1, b2;
+        if (family == AF_INET) {
+            b1 = UNSAFE.getByte(address + OFFSET_SIN4_PORT);
+            b2 = UNSAFE.getByte(address + OFFSET_SIN4_PORT + 1);
+        } else {
+            b1 = UNSAFE.getByte(address + OFFSET_SIN6_PORT);
+            b2 = UNSAFE.getByte(address + OFFSET_SIN6_PORT + 1);
+        }
+        return (Byte.toUnsignedInt(b1) << 8) + Byte.toUnsignedInt(b2);
+    }
+
+    /**
+     * Return an InetAddress to represent the value of the address in the
+     * sin4_addr or sin6_addr fields.
+     */
+    private InetAddress address(int family) {
+        int len;
+        int offset;
+        int scope_id;
+        if (family == AF_INET) {
+            len = 4;
+            offset = OFFSET_SIN4_ADDR;
+            scope_id = 0;
+        } else {
+            len = 16;
+            offset = OFFSET_SIN6_ADDR;
+            scope_id = UNSAFE.getInt(address + OFFSET_SIN6_SCOPE_ID);
+        }
+        byte[] bytes = new byte[len];
+        UNSAFE.copyMemory(null, address + offset, bytes, ARRAY_BASE_OFFSET, len);
+        try {
+            if (scope_id == 0) {
+                return InetAddress.getByAddress(bytes);
+            } else {
+                return Inet6Address.getByAddress(null, bytes, scope_id);
+            }
+        } catch (UnknownHostException e) {
+            throw new InternalError(e);
+        }
+    }
+
+    private static native int AFINET();
+    private static native int AFINET6();
+    private static native int sizeofSOCKETADDRESS();
+    private static native int sizeofFamily();
+    private static native int offsetFamily();
+    private static native int offsetSin4Port();
+    private static native int offsetSin4Addr();
+    private static native int offsetSin6Port();
+    private static native int offsetSin6Addr();
+    private static native int offsetSin6ScopeId();
+
+    static {
+        IOUtil.load();
+    }
+}
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.base/share/native/libnio/ch/NativeSocketAddress.c	Sat Nov 30 16:21:19 2019 +0000
@@ -0,0 +1,90 @@
+/*
+ * Copyright (c) 2019, 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.
+ */
+
+ #include "jni.h"
+ #include "net_util.h"
+
+ #include "sun_nio_ch_NativeSocketAddress.h"
+
+ JNIEXPORT jint JNICALL
+ Java_sun_nio_ch_NativeSocketAddress_AFINET(JNIEnv* env, jclass clazz)
+ {
+     return AF_INET;
+ }
+
+ JNIEXPORT jint JNICALL
+ Java_sun_nio_ch_NativeSocketAddress_AFINET6(JNIEnv* env, jclass clazz)
+ {
+     return AF_INET6;
+ }
+
+ JNIEXPORT jint JNICALL
+ Java_sun_nio_ch_NativeSocketAddress_sizeofSOCKETADDRESS(JNIEnv* env, jclass clazz)
+ {
+     return sizeof(SOCKETADDRESS);
+ }
+
+JNIEXPORT jint JNICALL
+Java_sun_nio_ch_NativeSocketAddress_sizeofFamily(JNIEnv* env, jclass clazz)
+{
+    // sizeof(struct sockaddr, sa_family)
+    return sizeof(((struct sockaddr *)0)->sa_family);
+}
+
+ JNIEXPORT jint JNICALL
+ Java_sun_nio_ch_NativeSocketAddress_offsetFamily(JNIEnv* env, jclass clazz)
+ {
+     return offsetof(struct sockaddr, sa_family);
+ }
+
+ JNIEXPORT jint JNICALL
+ Java_sun_nio_ch_NativeSocketAddress_offsetSin4Port(JNIEnv* env, jclass clazz)
+ {
+     return offsetof(struct sockaddr_in, sin_port);
+ }
+
+ JNIEXPORT jint JNICALL
+ Java_sun_nio_ch_NativeSocketAddress_offsetSin4Addr(JNIEnv* env, jclass clazz)
+ {
+     return offsetof(struct sockaddr_in, sin_addr);
+ }
+
+ JNIEXPORT jint JNICALL
+ Java_sun_nio_ch_NativeSocketAddress_offsetSin6Port(JNIEnv* env, jclass clazz)
+ {
+     return offsetof(struct sockaddr_in6, sin6_port);
+ }
+
+ JNIEXPORT jint JNICALL
+ Java_sun_nio_ch_NativeSocketAddress_offsetSin6Addr(JNIEnv* env, jclass clazz)
+ {
+     return offsetof(struct sockaddr_in6, sin6_addr);
+ }
+
+ JNIEXPORT jint JNICALL
+ Java_sun_nio_ch_NativeSocketAddress_offsetSin6ScopeId(JNIEnv* env, jclass clazz)
+ {
+     return offsetof(struct sockaddr_in6, sin6_scope_id);
+ }
--- a/src/java.base/unix/native/libnio/ch/DatagramChannelImpl.c	Fri Nov 29 14:11:50 2019 -0800
+++ b/src/java.base/unix/native/libnio/ch/DatagramChannelImpl.c	Sat Nov 30 16:21:19 2019 +0000
@@ -23,11 +23,6 @@
  * questions.
  */
 
-#include "jni.h"
-#include "jni_util.h"
-#include "jvm.h"
-#include "jlong.h"
-
 #include <netdb.h>
 #include <sys/types.h>
 #include <sys/socket.h>
@@ -39,49 +34,17 @@
 #include <netinet/in.h>
 #endif
 
+#include "jni.h"
+#include "jni_util.h"
+#include "jlong.h"
 #include "net_util.h"
-#include "net_util_md.h"
 #include "nio.h"
 #include "nio_util.h"
 
 #include "sun_nio_ch_DatagramChannelImpl.h"
 
-static jfieldID dci_senderID;   /* sender in sun.nio.ch.DatagramChannelImpl */
-static jfieldID dci_senderAddrID; /* sender InetAddress in sun.nio.ch.DatagramChannelImpl */
-static jfieldID dci_senderPortID; /* sender port in sun.nio.ch.DatagramChannelImpl */
-static jclass isa_class;        /* java.net.InetSocketAddress */
-static jmethodID isa_ctorID;    /*   .InetSocketAddress(InetAddress, int) */
-
 JNIEXPORT void JNICALL
-Java_sun_nio_ch_DatagramChannelImpl_initIDs(JNIEnv *env, jclass clazz)
-{
-    clazz = (*env)->FindClass(env, "java/net/InetSocketAddress");
-    CHECK_NULL(clazz);
-    isa_class = (*env)->NewGlobalRef(env, clazz);
-    if (isa_class == NULL) {
-        JNU_ThrowOutOfMemoryError(env, NULL);
-        return;
-    }
-    isa_ctorID = (*env)->GetMethodID(env, clazz, "<init>",
-                                     "(Ljava/net/InetAddress;I)V");
-    CHECK_NULL(isa_ctorID);
-
-    clazz = (*env)->FindClass(env, "sun/nio/ch/DatagramChannelImpl");
-    CHECK_NULL(clazz);
-    dci_senderID = (*env)->GetFieldID(env, clazz, "sender",
-                                      "Ljava/net/SocketAddress;");
-    CHECK_NULL(dci_senderID);
-    dci_senderAddrID = (*env)->GetFieldID(env, clazz,
-                                          "cachedSenderInetAddress",
-                                          "Ljava/net/InetAddress;");
-    CHECK_NULL(dci_senderAddrID);
-    dci_senderPortID = (*env)->GetFieldID(env, clazz,
-                                          "cachedSenderPort", "I");
-    CHECK_NULL(dci_senderPortID);
-}
-
-JNIEXPORT void JNICALL
-Java_sun_nio_ch_DatagramChannelImpl_disconnect0(JNIEnv *env, jobject this,
+Java_sun_nio_ch_DatagramChannelImpl_disconnect0(JNIEnv *env, jclass clazz,
                                                 jobject fdo, jboolean isIPv6)
 {
     jint fd = fdval(env, fdo);
@@ -122,17 +85,17 @@
 }
 
 JNIEXPORT jint JNICALL
-Java_sun_nio_ch_DatagramChannelImpl_receive0(JNIEnv *env, jobject this,
-                                             jobject fdo, jlong address,
-                                             jint len, jboolean connected)
+Java_sun_nio_ch_DatagramChannelImpl_receive0(JNIEnv *env, jclass clazz,
+                                             jobject fdo, jlong bufAddress,
+                                             jint len, jlong senderAddress,
+                                             jboolean connected)
 {
     jint fd = fdval(env, fdo);
-    void *buf = (void *)jlong_to_ptr(address);
-    SOCKETADDRESS sa;
+    void *buf = (void *)jlong_to_ptr(bufAddress);
+    SOCKETADDRESS *sa = (SOCKETADDRESS *)jlong_to_ptr(senderAddress);
     socklen_t sa_len = sizeof(SOCKETADDRESS);
     jboolean retry = JNI_FALSE;
-    jint n = 0;
-    jobject senderAddr;
+    jint n;
 
     if (len > MAX_PACKET_LEN) {
         len = MAX_PACKET_LEN;
@@ -140,7 +103,7 @@
 
     do {
         retry = JNI_FALSE;
-        n = recvfrom(fd, buf, len, 0, &sa.sa, &sa_len);
+        n = recvfrom(fd, buf, len, 0, (struct sockaddr *)sa, &sa_len);
         if (n < 0) {
             if (errno == EAGAIN || errno == EWOULDBLOCK) {
                 return IOS_UNAVAILABLE;
@@ -152,8 +115,7 @@
                 if (connected == JNI_FALSE) {
                     retry = JNI_TRUE;
                 } else {
-                    JNU_ThrowByName(env, JNU_JAVANETPKG
-                                    "PortUnreachableException", 0);
+                    JNU_ThrowByName(env, JNU_JAVANETPKG "PortUnreachableException", 0);
                     return IOS_THROWN;
                 }
             } else {
@@ -162,41 +124,11 @@
         }
     } while (retry == JNI_TRUE);
 
-    /*
-     * If the source address and port match the cached address
-     * and port in DatagramChannelImpl then we don't need to
-     * create InetAddress and InetSocketAddress objects.
-     */
-    senderAddr = (*env)->GetObjectField(env, this, dci_senderAddrID);
-    if (senderAddr != NULL) {
-        if (!NET_SockaddrEqualsInetAddress(env, &sa, senderAddr)) {
-            senderAddr = NULL;
-        } else {
-            jint port = (*env)->GetIntField(env, this, dci_senderPortID);
-            if (port != NET_GetPortFromSockaddr(&sa)) {
-                senderAddr = NULL;
-            }
-        }
-    }
-    if (senderAddr == NULL) {
-        jobject isa = NULL;
-        int port = 0;
-        jobject ia = NET_SockaddrToInetAddress(env, &sa, &port);
-        if (ia != NULL) {
-            isa = (*env)->NewObject(env, isa_class, isa_ctorID, ia, port);
-        }
-        CHECK_NULL_RETURN(isa, IOS_THROWN);
-
-        (*env)->SetObjectField(env, this, dci_senderAddrID, ia);
-        (*env)->SetIntField(env, this, dci_senderPortID,
-                            NET_GetPortFromSockaddr(&sa));
-        (*env)->SetObjectField(env, this, dci_senderID, isa);
-    }
     return n;
 }
 
 JNIEXPORT jint JNICALL
-Java_sun_nio_ch_DatagramChannelImpl_send0(JNIEnv *env, jobject this,
+Java_sun_nio_ch_DatagramChannelImpl_send0(JNIEnv *env, jclass clazz,
                                           jboolean preferIPv6, jobject fdo, jlong address,
                                           jint len, jobject destAddress, jint destPort)
 {
--- a/src/java.base/windows/native/libnio/ch/DatagramChannelImpl.c	Fri Nov 29 14:11:50 2019 -0800
+++ b/src/java.base/windows/native/libnio/ch/DatagramChannelImpl.c	Sat Nov 30 16:21:19 2019 +0000
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2001, 2012, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2019, 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
@@ -23,51 +23,16 @@
  * questions.
  */
 
-#include "jni.h"
-#include "jni_util.h"
-#include "jvm.h"
-#include "jlong.h"
-#include <io.h>
-#include "sun_nio_ch_DatagramChannelImpl.h"
-#include "nio.h"
-#include "nio_util.h"
-#include "net_util.h"
 #include <winsock2.h>
 
-static jfieldID dci_senderID;   /* sender in sun.nio.ch.DatagramChannelImpl */
-static jfieldID dci_senderAddrID; /* sender InetAddress in sun.nio.ch.DatagramChannelImpl */
-static jfieldID dci_senderPortID; /* sender port in sun.nio.ch.DatagramChannelImpl */
-static jclass isa_class;        /* java.net.InetSocketAddress */
-static jmethodID isa_ctorID;    /* java.net.InetSocketAddress(InetAddress, int) */
-
+#include "jni.h"
+#include "jni_util.h"
+#include "jlong.h"
+#include "net_util.h"
+#include "nio.h"
+#include "nio_util.h"
 
-JNIEXPORT void JNICALL
-Java_sun_nio_ch_DatagramChannelImpl_initIDs(JNIEnv *env, jclass clazz)
-{
-    clazz = (*env)->FindClass(env, "java/net/InetSocketAddress");
-    CHECK_NULL(clazz);
-    isa_class = (*env)->NewGlobalRef(env, clazz);
-    if (isa_class == NULL) {
-        JNU_ThrowOutOfMemoryError(env, NULL);
-        return;
-    }
-    isa_ctorID = (*env)->GetMethodID(env, clazz, "<init>",
-                                     "(Ljava/net/InetAddress;I)V");
-    CHECK_NULL(isa_ctorID);
-
-    clazz = (*env)->FindClass(env, "sun/nio/ch/DatagramChannelImpl");
-    CHECK_NULL(clazz);
-    dci_senderID = (*env)->GetFieldID(env, clazz, "sender",
-                                      "Ljava/net/SocketAddress;");
-    CHECK_NULL(dci_senderID);
-    dci_senderAddrID = (*env)->GetFieldID(env, clazz,
-                                          "cachedSenderInetAddress",
-                                          "Ljava/net/InetAddress;");
-    CHECK_NULL(dci_senderAddrID);
-    dci_senderPortID = (*env)->GetFieldID(env, clazz,
-                                          "cachedSenderPort", "I");
-    CHECK_NULL(dci_senderPortID);
-}
+#include "sun_nio_ch_DatagramChannelImpl.h"
 
 /*
  * This function "purges" all outstanding ICMP port unreachable packets
@@ -112,7 +77,7 @@
 }
 
 JNIEXPORT void JNICALL
-Java_sun_nio_ch_DatagramChannelImpl_disconnect0(JNIEnv *env, jobject this,
+Java_sun_nio_ch_DatagramChannelImpl_disconnect0(JNIEnv *env, jclass clazz,
                                                 jobject fdo, jboolean isIPv6)
 {
     jint fd = fdval(env, fdo);
@@ -135,17 +100,17 @@
 }
 
 JNIEXPORT jint JNICALL
-Java_sun_nio_ch_DatagramChannelImpl_receive0(JNIEnv *env, jobject this,
-                                            jobject fdo, jlong address,
-                                            jint len, jboolean connected)
+Java_sun_nio_ch_DatagramChannelImpl_receive0(JNIEnv *env, jclass clazz,
+                                             jobject fdo, jlong bufAddress,
+                                             jint len, jlong senderAddress,
+                                             jboolean connected)
 {
     jint fd = fdval(env, fdo);
-    void *buf = (void *)jlong_to_ptr(address);
-    SOCKETADDRESS sa;
-    int sa_len = sizeof(sa);
+    void *buf = (void *)jlong_to_ptr(bufAddress);
+    SOCKETADDRESS *sa = (SOCKETADDRESS *)jlong_to_ptr(senderAddress);
+    int sa_len = sizeof(SOCKETADDRESS);
     BOOL retry = FALSE;
     jint n;
-    jobject senderAddr;
 
     do {
         retry = FALSE;
@@ -153,7 +118,7 @@
                      (char *)buf,
                      len,
                      0,
-                     &sa.sa,
+                     (struct sockaddr *)sa,
                      &sa_len);
 
         if (n == SOCKET_ERROR) {
@@ -162,7 +127,7 @@
                 /* Spec says the rest of the data will be discarded... */
                 n = len;
             } else if (theErr == WSAECONNRESET) {
-                purgeOutstandingICMP(env, this, fd);
+                purgeOutstandingICMP(env, clazz, fd);
                 if (connected == JNI_FALSE) {
                     retry = TRUE;
                 } else {
@@ -175,42 +140,11 @@
         }
     } while (retry);
 
-    /*
-     * If the source address and port match the cached address
-     * and port in DatagramChannelImpl then we don't need to
-     * create InetAddress and InetSocketAddress objects.
-     */
-    senderAddr = (*env)->GetObjectField(env, this, dci_senderAddrID);
-    if (senderAddr != NULL) {
-        if (!NET_SockaddrEqualsInetAddress(env, &sa, senderAddr)) {
-            senderAddr = NULL;
-        } else {
-            jint port = (*env)->GetIntField(env, this, dci_senderPortID);
-            if (port != NET_GetPortFromSockaddr(&sa)) {
-                senderAddr = NULL;
-            }
-        }
-    }
-    if (senderAddr == NULL) {
-        jobject isa = NULL;
-        int port;
-        jobject ia = NET_SockaddrToInetAddress(env, &sa, &port);
-        if (ia != NULL) {
-            isa = (*env)->NewObject(env, isa_class, isa_ctorID, ia, port);
-        }
-        CHECK_NULL_RETURN(isa, IOS_THROWN);
-
-        // update cachedSenderInetAddress/cachedSenderPort
-        (*env)->SetObjectField(env, this, dci_senderAddrID, ia);
-        (*env)->SetIntField(env, this, dci_senderPortID,
-                            NET_GetPortFromSockaddr(&sa));
-        (*env)->SetObjectField(env, this, dci_senderID, isa);
-    }
     return n;
 }
 
 JNIEXPORT jint JNICALL
-Java_sun_nio_ch_DatagramChannelImpl_send0(JNIEnv *env, jobject this,
+Java_sun_nio_ch_DatagramChannelImpl_send0(JNIEnv *env, jclass clazz,
                                           jboolean preferIPv6, jobject fdo,
                                           jlong address, jint len,
                                           jobject destAddress, jint destPort)
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/jdk/java/nio/channels/DatagramChannel/ManySenders.java	Sat Nov 30 16:21:19 2019 +0000
@@ -0,0 +1,119 @@
+/*
+ * Copyright (c) 2019, 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.
+ *
+ * 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.
+ */
+
+/* @test
+ * @bug 8234805
+ * @summary Test that DatagramChannel.receive returns the expected sender address
+ * @run main ManySenders
+ * @run main/othervm -Djava.net.preferIPv4Stack=true ManySenders
+ */
+
+import java.io.ByteArrayInputStream;
+import java.io.ByteArrayOutputStream;
+import java.io.ObjectInputStream;
+import java.io.ObjectOutputStream;
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
+import java.net.NetworkInterface;
+import java.net.SocketAddress;
+import java.nio.ByteBuffer;
+import java.nio.channels.DatagramChannel;
+import java.util.List;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+public class ManySenders {
+    public static void main(String[] args) throws Exception {
+
+        // use addresses on interfaces that have the loopback and local host
+        InetAddress lh = InetAddress.getLocalHost();
+        InetAddress lb = InetAddress.getLoopbackAddress();
+        List<InetAddress> addresses = Stream.concat(
+                NetworkInterface.getByInetAddress(lh).inetAddresses(),
+                NetworkInterface.getByInetAddress(lb).inetAddresses())
+                .filter(ia -> !ia.isAnyLocalAddress())
+                .distinct()
+                .collect(Collectors.toList());
+
+        // bind DatagramChannel to wildcard address so it can receive from any address
+        try (DatagramChannel reader = DatagramChannel.open()) {
+            reader.bind(new InetSocketAddress(0));
+            for (InetAddress address : addresses) {
+                System.out.format("%n-- %s --%n", address.getHostAddress());
+
+                // send 3 datagrams from the given address to the reader
+                test(3, address, reader);
+            }
+        }
+    }
+
+    static void test(int count, InetAddress address, DatagramChannel reader) throws Exception {
+        int remotePort = reader.socket().getLocalPort();
+        InetSocketAddress remote = new InetSocketAddress(address, remotePort);
+
+        try (DatagramChannel sender = DatagramChannel.open()) {
+            sender.bind(new InetSocketAddress(address, 0));
+
+            SocketAddress local = sender.getLocalAddress();
+            byte[] bytes = serialize(local);
+
+            SocketAddress previousSource = null;
+            for (int i = 0; i < count; i++) {
+                System.out.format("send %s -> %s%n", local, remote);
+                sender.send(ByteBuffer.wrap(bytes), remote);
+
+                ByteBuffer bb = ByteBuffer.allocate(1000);
+                SocketAddress source = reader.receive(bb);
+                System.out.format("received datagram from %s%n", source);
+
+                // check source address and payload
+                SocketAddress payload = deserialize(bb.array());
+                if (!source.equals(local))
+                    throw new RuntimeException("source=" + source + ", expected=" + local);
+                if (!payload.equals(local))
+                    throw new RuntimeException("payload=" + payload + ", expected=" + local);
+
+                // check that cached source was used
+                if (previousSource == null) {
+                    previousSource = source;
+                } else if (source != previousSource) {
+                    throw new RuntimeException("Cached SocketAddress not returned");
+                }
+            }
+        }
+    }
+
+    private static byte[] serialize(SocketAddress address) throws Exception {
+        ByteArrayOutputStream baos = new ByteArrayOutputStream();
+        ObjectOutputStream oos = new ObjectOutputStream(baos);
+        oos.writeObject(address);
+        oos.close();
+        return baos.toByteArray();
+    }
+
+    private static SocketAddress deserialize(byte[] bytes) throws Exception {
+        ByteArrayInputStream bais = new ByteArrayInputStream(bytes);
+        ObjectInputStream ois = new ObjectInputStream(bais);
+        return (SocketAddress) ois.readObject();
+    }
+}
\ No newline at end of file