8008972: Memory leak: Java_java_net_TwoStacksPlainDatagramSocketImpl_receive0 [parfait]

Summary: Modified the code so that "jumbo frames" are truncated before buffer allocation is considered. This makes the buffer length a reliable indication that a buffer has been allocated, and it can then be used during clean up.
Reviewed-by: chegar, khazra, alanb
Contributed-by: john.zavgren@oracle.com

src/windows/native/java/net/DualStackPlainDatagramSocketImpl.c

@@ -256,14 +256,14 @@ JNIEXPORT jint JNICALL Java_java_net_DualStackPlainDatagramSocketImpl_socketRece
     packetBuffer = (*env)->GetObjectField(env, dpObj, dp_bufID);
     packetBufferOffset = (*env)->GetIntField(env, dpObj, dp_offsetID);
     packetBufferLen = (*env)->GetIntField(env, dpObj, dp_bufLengthID);
-
-    if (packetBufferLen > MAX_BUFFER_LEN) {
     /* Note: the buffer needn't be greater than 65,536 (0xFFFF)
     * the max size of an IP packet. Anything bigger is truncated anyway.
     */
     if (packetBufferLen > MAX_PACKET_LEN) {
         packetBufferLen = MAX_PACKET_LEN;
     }
+
+    if (packetBufferLen > MAX_BUFFER_LEN) {
         fullPacket = (char *)malloc(packetBufferLen);
         if (!fullPacket) {
             JNU_ThrowOutOfMemoryError(env, "Native heap allocation failed");

src/windows/native/java/net/TwoStacksPlainDatagramSocketImpl.c

@@ -145,7 +145,7 @@ static int getFD1(JNIEnv *env, jobject this) {
 /*
  * This function returns JNI_TRUE if the datagram size exceeds the underlying
  * provider's ability to send to the target address. The following OS
- * oddies have been observed :-
+ * oddities have been observed :-
  *
  * 1. On Windows 95/98 if we try to send a datagram > 12k to an application
  *    on the same machine then the send will fail silently.
@@ -218,7 +218,7 @@ jboolean exceedSizeLimit(JNIEnv *env, jint fd, jint addr, jint size)
 
             /*
              * Step 3: On Windows 95/98 then enumerate the IP addresses on
-             * this machine. This is necesary because we need to check if the
+             * this machine. This is neccesary because we need to check if the
              * datagram is being sent to an application on the same machine.
              */
             if (is95or98) {
@@ -565,8 +565,8 @@ Java_java_net_TwoStacksPlainDatagramSocketImpl_connect0(JNIEnv *env, jobject thi
 
     if (xp_or_later) {
         /* SIO_UDP_CONNRESET fixes a bug introduced in Windows 2000, which
-         * returns connection reset errors un connected UDP sockets (as well
-         * as connected sockets. The solution is to only enable this feature
+         * returns connection reset errors on connected UDP sockets (as well
+         * as connected sockets). The solution is to only enable this feature
          * when the socket is connected
          */
         DWORD x1, x2; /* ignored result codes */
@@ -690,6 +690,12 @@ Java_java_net_TwoStacksPlainDatagramSocketImpl_send(JNIEnv *env, jobject this,
     fd = (*env)->GetIntField(env, fdObj, IO_fd_fdID);
 
     packetBufferLen = (*env)->GetIntField(env, packet, dp_lengthID);
+    /* Note: the buffer needn't be greater than 65,536 (0xFFFF)...
+     * the maximum size of an IP packet. Anything bigger is truncated anyway.
+     */
+    if (packetBufferLen > MAX_PACKET_LEN) {
+        packetBufferLen = MAX_PACKET_LEN;
+    }
 
     if (connected) {
         addrp = 0; /* arg to JVM_Sendto () null in this case */
@@ -728,7 +734,7 @@ Java_java_net_TwoStacksPlainDatagramSocketImpl_send(JNIEnv *env, jobject this,
         }
 
         /* When JNI-ifying the JDK's IO routines, we turned
-         * read's and write's of byte arrays of size greater
+         * reads and writes of byte arrays of size greater
          * than 2048 bytes into several operations of size 2048.
          * This saves a malloc()/memcpy()/free() for big
          * buffers.  This is OK for file IO and TCP, but that