initial checkin of tls API

tls/build.gradle

@@ -0,0 +1,13 @@
+dependencies {
+    compile project(':core')
+    compile project(':prov')
+}
+
+cobertura {
+   coverageDirs = [
+       "${rootProject.projectDir}/core/build/classes/main",
+       "${rootProject.projectDir}/prov/build/classes/main",
+       "${rootProject.projectDir}/tls/build/classes/main"
+  ]
+}
+

tls/src/main/j2me/org/bouncycastle/tls/UDPTransport.java

@@ -0,0 +1,107 @@
+package org.bouncycastle.tls;
+
+import java.io.IOException;
+import javax.microedition.io.DatagramConnection;
+import javax.microedition.io.Datagram;
+
+public class UDPTransport
+    implements DatagramTransport
+{
+
+    protected final static int MIN_IP_OVERHEAD = 20;
+    protected final static int MAX_IP_OVERHEAD = MIN_IP_OVERHEAD + 64;
+    protected final static int UDP_OVERHEAD = 8;
+
+    protected final DatagramConnection socket;
+    protected final int receiveLimit, sendLimit;
+
+    public UDPTransport(DatagramConnection socket, int mtu)
+        throws IOException
+    {
+        //
+        // In 1.3 and earlier sockets were bound and connected during creation
+        //
+        //if (!socket.isBound() || !socket.isConnected())
+        //{
+        //    throw new IllegalArgumentException("'socket' must be bound and connected");
+        //}
+
+        this.socket = socket;
+
+        // NOTE: As of JDK 1.6, can use NetworkInterface.getMTU
+
+        this.receiveLimit = mtu - MIN_IP_OVERHEAD - UDP_OVERHEAD;
+        this.sendLimit = mtu - MAX_IP_OVERHEAD - UDP_OVERHEAD;
+    }
+
+    public int getReceiveLimit()
+    {
+        return receiveLimit;
+    }
+
+    public int getSendLimit()
+    {
+        // TODO[DTLS] Implement Path-MTU discovery?
+        return sendLimit;
+    }
+
+    public int receive(byte[] buf, int off, int len, int waitMillis)
+        throws IOException
+    {
+        //socket.setSoTimeout(waitMillis); -- not applicable
+
+        if (off == 0)
+        {
+            Datagram packet = socket.newDatagram(buf, len);
+            socket.receive(packet);
+
+            return packet.getLength();
+        }
+        else
+        {
+            byte[] rv = new byte[len];
+
+            Datagram packet = socket.newDatagram(rv, len);
+            socket.receive(packet);
+
+            System.arraycopy(rv, 0, buf, off, packet.getLength());
+
+            return packet.getLength();
+        }
+    }
+
+    public void send(byte[] buf, int off, int len)
+        throws IOException
+    {
+        if (len > getSendLimit())
+        {
+            /*
+             * RFC 4347 4.1.1. "If the application attempts to send a record larger than the MTU,
+             * the DTLS implementation SHOULD generate an error, thus avoiding sending a packet
+             * which will be fragmented."
+             */
+            throw new TlsFatalAlert(AlertDescription.internal_error);
+        }
+
+        if (off == 0)
+        {
+            Datagram packet = socket.newDatagram(buf, len);
+            socket.send(packet);
+        }
+        else
+        {
+            byte[] data = new byte[len];
+
+            System.arraycopy(buf, off, data, 0, len);
+
+            Datagram packet = socket.newDatagram(data, len);
+            socket.send(packet);
+        }
+    }
+
+    public void close()
+        throws IOException
+    {
+        socket.close();
+    }
+}