| /* |
| * Copyright (c) 1995, 2014, 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 java.net; |
| |
| import java.io.IOException; |
| import java.util.Enumeration; |
| |
| /** |
| * The multicast datagram socket class is useful for sending |
| * and receiving IP multicast packets. A MulticastSocket is |
| * a (UDP) DatagramSocket, with additional capabilities for |
| * joining "groups" of other multicast hosts on the internet. |
| * <P> |
| * A multicast group is specified by a class D IP address |
| * and by a standard UDP port number. Class D IP addresses |
| * are in the range <CODE>224.0.0.0</CODE> to <CODE>239.255.255.255</CODE>, |
| * inclusive. The address 224.0.0.0 is reserved and should not be used. |
| * <P> |
| * One would join a multicast group by first creating a MulticastSocket |
| * with the desired port, then invoking the |
| * <CODE>joinGroup(InetAddress groupAddr)</CODE> |
| * method: |
| * <PRE> |
| * // join a Multicast group and send the group salutations |
| * ... |
| * String msg = "Hello"; |
| * InetAddress group = InetAddress.getByName("228.5.6.7"); |
| * MulticastSocket s = new MulticastSocket(6789); |
| * s.joinGroup(group); |
| * DatagramPacket hi = new DatagramPacket(msg.getBytes(), msg.length(), |
| * group, 6789); |
| * s.send(hi); |
| * // get their responses! |
| * byte[] buf = new byte[1000]; |
| * DatagramPacket recv = new DatagramPacket(buf, buf.length); |
| * s.receive(recv); |
| * ... |
| * // OK, I'm done talking - leave the group... |
| * s.leaveGroup(group); |
| * </PRE> |
| * |
| * When one sends a message to a multicast group, <B>all</B> subscribing |
| * recipients to that host and port receive the message (within the |
| * time-to-live range of the packet, see below). The socket needn't |
| * be a member of the multicast group to send messages to it. |
| * <P> |
| * When a socket subscribes to a multicast group/port, it receives |
| * datagrams sent by other hosts to the group/port, as do all other |
| * members of the group and port. A socket relinquishes membership |
| * in a group by the leaveGroup(InetAddress addr) method. <B> |
| * Multiple MulticastSocket's</B> may subscribe to a multicast group |
| * and port concurrently, and they will all receive group datagrams. |
| * <P> |
| * Currently applets are not allowed to use multicast sockets. |
| * |
| * @author Pavani Diwanji |
| * @since JDK1.1 |
| */ |
| public |
| class MulticastSocket extends DatagramSocket { |
| |
| /** |
| * Used on some platforms to record if an outgoing interface |
| * has been set for this socket. |
| */ |
| private boolean interfaceSet; |
| |
| /** |
| * Create a multicast socket. |
| * |
| * <p>If there is a security manager, |
| * its {@code checkListen} method is first called |
| * with 0 as its argument to ensure the operation is allowed. |
| * This could result in a SecurityException. |
| * <p> |
| * When the socket is created the |
| * {@link DatagramSocket#setReuseAddress(boolean)} method is |
| * called to enable the SO_REUSEADDR socket option. |
| * |
| * @exception IOException if an I/O exception occurs |
| * while creating the MulticastSocket |
| * @exception SecurityException if a security manager exists and its |
| * {@code checkListen} method doesn't allow the operation. |
| * @see SecurityManager#checkListen |
| * @see java.net.DatagramSocket#setReuseAddress(boolean) |
| */ |
| public MulticastSocket() throws IOException { |
| this(new InetSocketAddress(0)); |
| } |
| |
| /** |
| * Create a multicast socket and bind it to a specific port. |
| * |
| * <p>If there is a security manager, |
| * its {@code checkListen} method is first called |
| * with the {@code port} argument |
| * as its argument to ensure the operation is allowed. |
| * This could result in a SecurityException. |
| * <p> |
| * When the socket is created the |
| * {@link DatagramSocket#setReuseAddress(boolean)} method is |
| * called to enable the SO_REUSEADDR socket option. |
| * |
| * @param port port to use |
| * @exception IOException if an I/O exception occurs |
| * while creating the MulticastSocket |
| * @exception SecurityException if a security manager exists and its |
| * {@code checkListen} method doesn't allow the operation. |
| * @see SecurityManager#checkListen |
| * @see java.net.DatagramSocket#setReuseAddress(boolean) |
| */ |
| public MulticastSocket(int port) throws IOException { |
| this(new InetSocketAddress(port)); |
| } |
| |
| /** |
| * Create a MulticastSocket bound to the specified socket address. |
| * <p> |
| * Or, if the address is {@code null}, create an unbound socket. |
| * |
| * <p>If there is a security manager, |
| * its {@code checkListen} method is first called |
| * with the SocketAddress port as its argument to ensure the operation is allowed. |
| * This could result in a SecurityException. |
| * <p> |
| * When the socket is created the |
| * {@link DatagramSocket#setReuseAddress(boolean)} method is |
| * called to enable the SO_REUSEADDR socket option. |
| * |
| * @param bindaddr Socket address to bind to, or {@code null} for |
| * an unbound socket. |
| * @exception IOException if an I/O exception occurs |
| * while creating the MulticastSocket |
| * @exception SecurityException if a security manager exists and its |
| * {@code checkListen} method doesn't allow the operation. |
| * @see SecurityManager#checkListen |
| * @see java.net.DatagramSocket#setReuseAddress(boolean) |
| * |
| * @since 1.4 |
| */ |
| public MulticastSocket(SocketAddress bindaddr) throws IOException { |
| super((SocketAddress) null); |
| |
| // Enable SO_REUSEADDR before binding |
| setReuseAddress(true); |
| |
| if (bindaddr != null) { |
| try { |
| bind(bindaddr); |
| } finally { |
| if (!isBound()) |
| close(); |
| } |
| } |
| } |
| |
| /** |
| * The lock on the socket's TTL. This is for set/getTTL and |
| * send(packet,ttl). |
| */ |
| private Object ttlLock = new Object(); |
| |
| /** |
| * The lock on the socket's interface - used by setInterface |
| * and getInterface |
| */ |
| private Object infLock = new Object(); |
| |
| /** |
| * The "last" interface set by setInterface on this MulticastSocket |
| */ |
| private InetAddress infAddress = null; |
| |
| |
| /** |
| * Set the default time-to-live for multicast packets sent out |
| * on this {@code MulticastSocket} in order to control the |
| * scope of the multicasts. |
| * |
| * <p>The ttl is an <b>unsigned</b> 8-bit quantity, and so <B>must</B> be |
| * in the range {@code 0 <= ttl <= 0xFF }. |
| * |
| * @param ttl the time-to-live |
| * @exception IOException if an I/O exception occurs |
| * while setting the default time-to-live value |
| * @deprecated use the setTimeToLive method instead, which uses |
| * <b>int</b> instead of <b>byte</b> as the type for ttl. |
| * @see #getTTL() |
| */ |
| @Deprecated |
| public void setTTL(byte ttl) throws IOException { |
| if (isClosed()) |
| throw new SocketException("Socket is closed"); |
| getImpl().setTTL(ttl); |
| } |
| |
| /** |
| * Set the default time-to-live for multicast packets sent out |
| * on this {@code MulticastSocket} in order to control the |
| * scope of the multicasts. |
| * |
| * <P> The ttl <B>must</B> be in the range {@code 0 <= ttl <= |
| * 255} or an {@code IllegalArgumentException} will be thrown. |
| * Multicast packets sent with a TTL of {@code 0} are not transmitted |
| * on the network but may be delivered locally. |
| * |
| * @param ttl |
| * the time-to-live |
| * |
| * @throws IOException |
| * if an I/O exception occurs while setting the |
| * default time-to-live value |
| * |
| * @see #getTimeToLive() |
| */ |
| public void setTimeToLive(int ttl) throws IOException { |
| if (ttl < 0 || ttl > 255) { |
| throw new IllegalArgumentException("ttl out of range"); |
| } |
| if (isClosed()) |
| throw new SocketException("Socket is closed"); |
| getImpl().setTimeToLive(ttl); |
| } |
| |
| /** |
| * Get the default time-to-live for multicast packets sent out on |
| * the socket. |
| * |
| * @exception IOException if an I/O exception occurs |
| * while getting the default time-to-live value |
| * @return the default time-to-live value |
| * @deprecated use the getTimeToLive method instead, which returns |
| * an <b>int</b> instead of a <b>byte</b>. |
| * @see #setTTL(byte) |
| */ |
| @Deprecated |
| public byte getTTL() throws IOException { |
| if (isClosed()) |
| throw new SocketException("Socket is closed"); |
| return getImpl().getTTL(); |
| } |
| |
| /** |
| * Get the default time-to-live for multicast packets sent out on |
| * the socket. |
| * @exception IOException if an I/O exception occurs while |
| * getting the default time-to-live value |
| * @return the default time-to-live value |
| * @see #setTimeToLive(int) |
| */ |
| public int getTimeToLive() throws IOException { |
| if (isClosed()) |
| throw new SocketException("Socket is closed"); |
| return getImpl().getTimeToLive(); |
| } |
| |
| /** |
| * Joins a multicast group. Its behavior may be affected by |
| * {@code setInterface} or {@code setNetworkInterface}. |
| * |
| * <p>If there is a security manager, this method first |
| * calls its {@code checkMulticast} method |
| * with the {@code mcastaddr} argument |
| * as its argument. |
| * |
| * @param mcastaddr is the multicast address to join |
| * |
| * @exception IOException if there is an error joining |
| * or when the address is not a multicast address. |
| * @exception SecurityException if a security manager exists and its |
| * {@code checkMulticast} method doesn't allow the join. |
| * |
| * @see SecurityManager#checkMulticast(InetAddress) |
| */ |
| public void joinGroup(InetAddress mcastaddr) throws IOException { |
| if (isClosed()) { |
| throw new SocketException("Socket is closed"); |
| } |
| |
| checkAddress(mcastaddr, "joinGroup"); |
| SecurityManager security = System.getSecurityManager(); |
| if (security != null) { |
| security.checkMulticast(mcastaddr); |
| } |
| |
| if (!mcastaddr.isMulticastAddress()) { |
| throw new SocketException("Not a multicast address"); |
| } |
| |
| /** |
| * required for some platforms where it's not possible to join |
| * a group without setting the interface first. |
| */ |
| NetworkInterface defaultInterface = NetworkInterface.getDefault(); |
| |
| if (!interfaceSet && defaultInterface != null) { |
| setNetworkInterface(defaultInterface); |
| } |
| |
| getImpl().join(mcastaddr); |
| } |
| |
| /** |
| * Leave a multicast group. Its behavior may be affected by |
| * {@code setInterface} or {@code setNetworkInterface}. |
| * |
| * <p>If there is a security manager, this method first |
| * calls its {@code checkMulticast} method |
| * with the {@code mcastaddr} argument |
| * as its argument. |
| * |
| * @param mcastaddr is the multicast address to leave |
| * @exception IOException if there is an error leaving |
| * or when the address is not a multicast address. |
| * @exception SecurityException if a security manager exists and its |
| * {@code checkMulticast} method doesn't allow the operation. |
| * |
| * @see SecurityManager#checkMulticast(InetAddress) |
| */ |
| public void leaveGroup(InetAddress mcastaddr) throws IOException { |
| if (isClosed()) { |
| throw new SocketException("Socket is closed"); |
| } |
| |
| checkAddress(mcastaddr, "leaveGroup"); |
| SecurityManager security = System.getSecurityManager(); |
| if (security != null) { |
| security.checkMulticast(mcastaddr); |
| } |
| |
| if (!mcastaddr.isMulticastAddress()) { |
| throw new SocketException("Not a multicast address"); |
| } |
| |
| getImpl().leave(mcastaddr); |
| } |
| |
| /** |
| * Joins the specified multicast group at the specified interface. |
| * |
| * <p>If there is a security manager, this method first |
| * calls its {@code checkMulticast} method |
| * with the {@code mcastaddr} argument |
| * as its argument. |
| * |
| * @param mcastaddr is the multicast address to join |
| * @param netIf specifies the local interface to receive multicast |
| * datagram packets, or <i>null</i> to defer to the interface set by |
| * {@link MulticastSocket#setInterface(InetAddress)} or |
| * {@link MulticastSocket#setNetworkInterface(NetworkInterface)} |
| * |
| * @exception IOException if there is an error joining |
| * or when the address is not a multicast address. |
| * @exception SecurityException if a security manager exists and its |
| * {@code checkMulticast} method doesn't allow the join. |
| * @throws IllegalArgumentException if mcastaddr is null or is a |
| * SocketAddress subclass not supported by this socket |
| * |
| * @see SecurityManager#checkMulticast(InetAddress) |
| * @since 1.4 |
| */ |
| public void joinGroup(SocketAddress mcastaddr, NetworkInterface netIf) |
| throws IOException { |
| if (isClosed()) |
| throw new SocketException("Socket is closed"); |
| |
| if (mcastaddr == null || !(mcastaddr instanceof InetSocketAddress)) |
| throw new IllegalArgumentException("Unsupported address type"); |
| |
| if (oldImpl) |
| throw new UnsupportedOperationException(); |
| |
| checkAddress(((InetSocketAddress)mcastaddr).getAddress(), "joinGroup"); |
| SecurityManager security = System.getSecurityManager(); |
| if (security != null) { |
| security.checkMulticast(((InetSocketAddress)mcastaddr).getAddress()); |
| } |
| |
| if (!((InetSocketAddress)mcastaddr).getAddress().isMulticastAddress()) { |
| throw new SocketException("Not a multicast address"); |
| } |
| |
| getImpl().joinGroup(mcastaddr, netIf); |
| } |
| |
| /** |
| * Leave a multicast group on a specified local interface. |
| * |
| * <p>If there is a security manager, this method first |
| * calls its {@code checkMulticast} method |
| * with the {@code mcastaddr} argument |
| * as its argument. |
| * |
| * @param mcastaddr is the multicast address to leave |
| * @param netIf specifies the local interface or <i>null</i> to defer |
| * to the interface set by |
| * {@link MulticastSocket#setInterface(InetAddress)} or |
| * {@link MulticastSocket#setNetworkInterface(NetworkInterface)} |
| * @exception IOException if there is an error leaving |
| * or when the address is not a multicast address. |
| * @exception SecurityException if a security manager exists and its |
| * {@code checkMulticast} method doesn't allow the operation. |
| * @throws IllegalArgumentException if mcastaddr is null or is a |
| * SocketAddress subclass not supported by this socket |
| * |
| * @see SecurityManager#checkMulticast(InetAddress) |
| * @since 1.4 |
| */ |
| public void leaveGroup(SocketAddress mcastaddr, NetworkInterface netIf) |
| throws IOException { |
| if (isClosed()) |
| throw new SocketException("Socket is closed"); |
| |
| if (mcastaddr == null || !(mcastaddr instanceof InetSocketAddress)) |
| throw new IllegalArgumentException("Unsupported address type"); |
| |
| if (oldImpl) |
| throw new UnsupportedOperationException(); |
| |
| checkAddress(((InetSocketAddress)mcastaddr).getAddress(), "leaveGroup"); |
| SecurityManager security = System.getSecurityManager(); |
| if (security != null) { |
| security.checkMulticast(((InetSocketAddress)mcastaddr).getAddress()); |
| } |
| |
| if (!((InetSocketAddress)mcastaddr).getAddress().isMulticastAddress()) { |
| throw new SocketException("Not a multicast address"); |
| } |
| |
| getImpl().leaveGroup(mcastaddr, netIf); |
| } |
| |
| /** |
| * Set the multicast network interface used by methods |
| * whose behavior would be affected by the value of the |
| * network interface. Useful for multihomed hosts. |
| * @param inf the InetAddress |
| * @exception SocketException if there is an error in |
| * the underlying protocol, such as a TCP error. |
| * @see #getInterface() |
| */ |
| public void setInterface(InetAddress inf) throws SocketException { |
| if (isClosed()) { |
| throw new SocketException("Socket is closed"); |
| } |
| checkAddress(inf, "setInterface"); |
| synchronized (infLock) { |
| getImpl().setOption(SocketOptions.IP_MULTICAST_IF, inf); |
| infAddress = inf; |
| interfaceSet = true; |
| } |
| } |
| |
| /** |
| * Retrieve the address of the network interface used for |
| * multicast packets. |
| * |
| * @return An {@code InetAddress} representing |
| * the address of the network interface used for |
| * multicast packets. |
| * |
| * @exception SocketException if there is an error in |
| * the underlying protocol, such as a TCP error. |
| * |
| * @see #setInterface(java.net.InetAddress) |
| */ |
| public InetAddress getInterface() throws SocketException { |
| if (isClosed()) { |
| throw new SocketException("Socket is closed"); |
| } |
| synchronized (infLock) { |
| InetAddress ia = |
| (InetAddress)getImpl().getOption(SocketOptions.IP_MULTICAST_IF); |
| |
| /** |
| * No previous setInterface or interface can be |
| * set using setNetworkInterface |
| */ |
| if (infAddress == null) { |
| return ia; |
| } |
| |
| /** |
| * Same interface set with setInterface? |
| */ |
| if (ia.equals(infAddress)) { |
| return ia; |
| } |
| |
| /** |
| * Different InetAddress from what we set with setInterface |
| * so enumerate the current interface to see if the |
| * address set by setInterface is bound to this interface. |
| */ |
| try { |
| NetworkInterface ni = NetworkInterface.getByInetAddress(ia); |
| Enumeration<InetAddress> addrs = ni.getInetAddresses(); |
| while (addrs.hasMoreElements()) { |
| InetAddress addr = addrs.nextElement(); |
| if (addr.equals(infAddress)) { |
| return infAddress; |
| } |
| } |
| |
| /** |
| * No match so reset infAddress to indicate that the |
| * interface has changed via means |
| */ |
| infAddress = null; |
| return ia; |
| } catch (Exception e) { |
| return ia; |
| } |
| } |
| } |
| |
| /** |
| * Specify the network interface for outgoing multicast datagrams |
| * sent on this socket. |
| * |
| * @param netIf the interface |
| * @exception SocketException if there is an error in |
| * the underlying protocol, such as a TCP error. |
| * @see #getNetworkInterface() |
| * @since 1.4 |
| */ |
| public void setNetworkInterface(NetworkInterface netIf) |
| throws SocketException { |
| |
| synchronized (infLock) { |
| getImpl().setOption(SocketOptions.IP_MULTICAST_IF2, netIf); |
| infAddress = null; |
| interfaceSet = true; |
| } |
| } |
| |
| /** |
| * Get the multicast network interface set. |
| * |
| * @exception SocketException if there is an error in |
| * the underlying protocol, such as a TCP error. |
| * @return the multicast {@code NetworkInterface} currently set |
| * @see #setNetworkInterface(NetworkInterface) |
| * @since 1.4 |
| */ |
| public NetworkInterface getNetworkInterface() throws SocketException { |
| // Android-changed: Support Integer IP_MULTICAST_IF2 values for app compat. |
| Integer niIndex |
| = (Integer)getImpl().getOption(SocketOptions.IP_MULTICAST_IF2); |
| if (niIndex == 0) { |
| InetAddress[] addrs = new InetAddress[1]; |
| addrs[0] = InetAddress.anyLocalAddress(); |
| return new NetworkInterface(addrs[0].getHostName(), 0, addrs); |
| } else { |
| return NetworkInterface.getByIndex(niIndex); |
| } |
| } |
| |
| /** |
| * Disable/Enable local loopback of multicast datagrams |
| * The option is used by the platform's networking code as a hint |
| * for setting whether multicast data will be looped back to |
| * the local socket. |
| * |
| * <p>Because this option is a hint, applications that want to |
| * verify what loopback mode is set to should call |
| * {@link #getLoopbackMode()} |
| * @param disable {@code true} to disable the LoopbackMode |
| * @throws SocketException if an error occurs while setting the value |
| * @since 1.4 |
| * @see #getLoopbackMode |
| */ |
| public void setLoopbackMode(boolean disable) throws SocketException { |
| getImpl().setOption(SocketOptions.IP_MULTICAST_LOOP, Boolean.valueOf(disable)); |
| } |
| |
| /** |
| * Get the setting for local loopback of multicast datagrams. |
| * |
| * @throws SocketException if an error occurs while getting the value |
| * @return true if the LoopbackMode has been disabled |
| * @since 1.4 |
| * @see #setLoopbackMode |
| */ |
| public boolean getLoopbackMode() throws SocketException { |
| return ((Boolean)getImpl().getOption(SocketOptions.IP_MULTICAST_LOOP)).booleanValue(); |
| } |
| |
| /** |
| * Sends a datagram packet to the destination, with a TTL (time- |
| * to-live) other than the default for the socket. This method |
| * need only be used in instances where a particular TTL is desired; |
| * otherwise it is preferable to set a TTL once on the socket, and |
| * use that default TTL for all packets. This method does <B>not |
| * </B> alter the default TTL for the socket. Its behavior may be |
| * affected by {@code setInterface}. |
| * |
| * <p>If there is a security manager, this method first performs some |
| * security checks. First, if {@code p.getAddress().isMulticastAddress()} |
| * is true, this method calls the |
| * security manager's {@code checkMulticast} method |
| * with {@code p.getAddress()} and {@code ttl} as its arguments. |
| * If the evaluation of that expression is false, |
| * this method instead calls the security manager's |
| * {@code checkConnect} method with arguments |
| * {@code p.getAddress().getHostAddress()} and |
| * {@code p.getPort()}. Each call to a security manager method |
| * could result in a SecurityException if the operation is not allowed. |
| * |
| * @param p is the packet to be sent. The packet should contain |
| * the destination multicast ip address and the data to be sent. |
| * One does not need to be the member of the group to send |
| * packets to a destination multicast address. |
| * @param ttl optional time to live for multicast packet. |
| * default ttl is 1. |
| * |
| * @exception IOException is raised if an error occurs i.e |
| * error while setting ttl. |
| * @exception SecurityException if a security manager exists and its |
| * {@code checkMulticast} or {@code checkConnect} |
| * method doesn't allow the send. |
| * |
| * @deprecated Use the following code or its equivalent instead: |
| * ...... |
| * int ttl = mcastSocket.getTimeToLive(); |
| * mcastSocket.setTimeToLive(newttl); |
| * mcastSocket.send(p); |
| * mcastSocket.setTimeToLive(ttl); |
| * ...... |
| * |
| * @see DatagramSocket#send |
| * @see DatagramSocket#receive |
| * @see SecurityManager#checkMulticast(java.net.InetAddress, byte) |
| * @see SecurityManager#checkConnect |
| */ |
| @Deprecated |
| public void send(DatagramPacket p, byte ttl) |
| throws IOException { |
| if (isClosed()) |
| throw new SocketException("Socket is closed"); |
| checkAddress(p.getAddress(), "send"); |
| synchronized(ttlLock) { |
| synchronized(p) { |
| if (connectState == ST_NOT_CONNECTED) { |
| // Security manager makes sure that the multicast address |
| // is allowed one and that the ttl used is less |
| // than the allowed maxttl. |
| SecurityManager security = System.getSecurityManager(); |
| if (security != null) { |
| if (p.getAddress().isMulticastAddress()) { |
| security.checkMulticast(p.getAddress(), ttl); |
| } else { |
| security.checkConnect(p.getAddress().getHostAddress(), |
| p.getPort()); |
| } |
| } |
| } else { |
| // we're connected |
| InetAddress packetAddress = null; |
| packetAddress = p.getAddress(); |
| if (packetAddress == null) { |
| p.setAddress(connectedAddress); |
| p.setPort(connectedPort); |
| } else if ((!packetAddress.equals(connectedAddress)) || |
| p.getPort() != connectedPort) { |
| throw new SecurityException("connected address and packet address" + |
| " differ"); |
| } |
| } |
| byte dttl = getTTL(); |
| try { |
| if (ttl != dttl) { |
| // set the ttl |
| getImpl().setTTL(ttl); |
| } |
| // call the datagram method to send |
| getImpl().send(p); |
| } finally { |
| // set it back to default |
| if (ttl != dttl) { |
| getImpl().setTTL(dttl); |
| } |
| } |
| } // synch p |
| } //synch ttl |
| } //method |
| } |
