UDP

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org.jgroups.protocols
Class UDP

java.lang.Object
  org.jgroups.stack.Protocol
      org.jgroups.protocols.TP
          org.jgroups.protocols.UDP

All Implemented Interfaces:: java.lang.Runnable

public class UDP
extends TP
implements java.lang.Runnable

IP multicast transport based on UDP. Messages to the group (msg.dest == null) will be multicast (to all group members), whereas point-to-point messages (msg.dest != null) will be unicast to a single member. Uses a multicast and a unicast socket.

The following properties are read by the UDP protocol:

param mcast_addr - the multicast address to use; default is 228.8.8.8.
param mcast_port - (int) the port that the multicast is sent on; default is 7600
param ip_mcast - (boolean) flag whether to use IP multicast; default is true.
param ip_ttl - the default time-to-live for multicast packets sent out on this socket; default is 32.
param use_packet_handler - boolean, defaults to false. If set, the mcast and ucast receiver threads just put the datagram's payload (a byte buffer) into a queue, from where a separate thread will dequeue and handle them (unmarshal and pass up). This frees the receiver threads from having to do message unmarshalling; this time can now be spent receiving packets. If you have lots of retransmissions because of network input buffer overflow, consider setting this property to true.

Nested Class Summary

class UDP.UcastReceiver


Nested classes inherited from class org.jgroups.protocols.TP

TP.IncomingMessageHandler, TP.IncomingPacketHandler, TP.IncomingQueueEntry, TP.OutgoingPacketHandler

Field Summary

(package private) boolean ip_mcast
          Whether to enable IP multicasting.

(package private) int ip_ttl
          The time-to-live (TTL) for multicast datagram packets

private static org.jgroups.util.BoundedList last_ports_used
          BoundedList of the last 100 ports used.

(package private) org.jgroups.stack.IpAddress mcast_addr
          The multicast address (mcast address and port) this member uses

(package private) java.lang.String mcast_addr_name
          The multicast address used for sending and receiving packets

(package private) int mcast_port
          The multicast port used for sending and receiving packets

(package private) java.lang.Thread mcast_receiver
          The multicast receiver thread

(package private) int mcast_recv_buf_size
          Receive buffer size of the multicast datagram socket

(package private) java.net.MulticastSocket mcast_recv_sock
          IP multicast socket for receiving multicast packets

(package private) int mcast_send_buf_size
          Send buffer size of the multicast datagram socket

(package private) java.net.MulticastSocket mcast_send_sock
          IP multicast socket for sending multicast packets

(package private) java.net.MulticastSocket[] mcast_send_sockets
          If we have multiple mcast send sockets, e.g.

(package private) int num_last_ports
          Maintain a list of local ports opened by DatagramSocket.

(package private) java.net.DatagramSocket sock
          Socket used for sending unicast packets and receiving unicast packets The address of this socket will be our local address (local_addr)

(package private) int tos
          Traffic class for sending unicast and multicast datagrams.

(package private) UDP.UcastReceiver ucast_receiver
          The unicast receiver thread

(package private) int ucast_recv_buf_size
          Receive buffer size of the unicast datagram socket

(package private) int ucast_send_buf_size
          Send buffer size of the unicast datagram socket

Fields inherited from class org.jgroups.protocols.TP

additional_data, addr_translation_table, bind_addr, bind_port, bind_to_all_interfaces, buf_in_stream, buf_out_stream, bundler, channel_name, diag_handler, diagnostics_addr, diagnostics_port, dis, discard_incompatible_packets, dos, enable_bundling, enable_diagnostics, f, header, in_stream, incoming_msg_handler, incoming_msg_queue, incoming_packet_handler, incoming_packet_queue, LIST, local_addr, loopback, max_bundle_size, max_bundle_timeout, members, MULTICAST, name, num_bytes_received, num_bytes_sent, num_msgs_received, num_msgs_sent, out_stream, outgoing_packet_handler, outgoing_queue, outgoing_queue_max_size, port_range, receive_interfaces, receive_on_all_interfaces, send_interfaces, send_on_all_interfaces, timer, use_addr_translation, use_incoming_packet_handler, use_local_host, use_outgoing_packet_handler, view

Fields inherited from class org.jgroups.stack.Protocol

down_handler, down_prot, down_queue, down_thread, down_thread_prio, log, observer, props, stack, stats, trace, up_handler, up_prot, up_queue, up_thread, up_thread_prio, warn

Constructor Summary

UDP()
          Creates the UDP protocol, and initializes the state variables, does however not start any sockets or threads.

Method Summary

private void _send(java.net.InetAddress dest, int port, boolean mcast, byte[] data, int offset, int length)


private void bindToInterfaces(java.util.List interfaces, java.net.MulticastSocket s, java.net.InetAddress mcastAddr)


(package private) void closeMulticastSocket()


private void closeSocket()


(package private) void closeSockets()
          Closed UDP unicast and multicast sockets

private java.net.DatagramSocket createDatagramSocketWithBindPort()
          Creates a DatagramSocket when bind_port > 0.

private java.net.DatagramSocket createEphemeralDatagramSocket()
          Creates a DatagramSocket with a random port.

private void createSockets()
          Create UDP sender and receiver sockets.

private java.lang.String dumpSocketInfo()


java.lang.String getInfo()


private org.jgroups.util.BoundedList getLastPortsUsed()


java.lang.String getName()


protected void handleConfigEvent(java.util.HashMap map)


void postUnmarshalling(org.jgroups.Message msg, org.jgroups.Address dest, org.jgroups.Address src, boolean multicast)


void postUnmarshallingList(org.jgroups.Message msg, org.jgroups.Address dest, boolean multicast)


void run()
          This method will be called by whoever wishes to run your class implementing Runnable.

void sendToAllMembers(byte[] data, int offset, int length)
          Send to all members in the group.

void sendToSingleMember(org.jgroups.Address dest, byte[] data, int offset, int length)
          Send to all members in the group.

private void setBufferSize(java.net.DatagramSocket sock, int send_buf_size, int recv_buf_size)


(package private) void setBufferSizes()


boolean setProperties(java.util.Properties props)
          Setup the Protocol instance acording to the configuration string.

void start()
          Creates the unicast and multicast sockets and starts the unicast and multicast receiver threads

(package private) void startThreads()
          Starts the unicast and multicast receiver threads

void stop()
          This method is called on a Channel.disconnect()>Channel.disconnect() 55 .

(package private) void stopThreads()
          Stops unicast and multicast receiver threads

Methods inherited from class org.jgroups.protocols.TP

down, dumpStats, getBindAddress, getBindToAllInterfaces, getChannelName, getIncomingQueueSize, getLocalAddress, getMaxBundleSize, getMaxBundleTimeout, getNumBytesReceived, getNumBytesSent, getNumMessagesReceived, getNumMessagesSent, getOutgoingQueueMaxSize, getOutgoingQueueSize, getReceiveInterfaces, getSendInterfaces, handleDownEvent, isDiscardIncompatiblePackets, isEnableBundling, isLoopback, isReceiveOnAllInterfaces, isSendOnAllInterfaces, isUseIncomingPacketHandler, isUseOutgoingPacketHandler, receive, resetStats, setBindAddress, setBindToAllInterfaces, setDiscardIncompatiblePackets, setEnableBundling, setLoopback, setMaxBundleSize, setMaxBundleTimeout, setOutgoingQueueMaxSize, startUpHandler, toString, up

Methods inherited from class org.jgroups.stack.Protocol

destroy, downThreadEnabled, enableStats, getDownProtocol, getDownQueue, getProperties, getUpProtocol, getUpQueue, handleSpecialDownEvent, init, isTrace, isWarn, passDown, passUp, printStats, providedDownServices, providedUpServices, receiveDownEvent, receiveUpEvent, requiredDownServices, requiredUpServices, setDownProtocol, setObserver, setPropertiesInternal, setProtocolStack, setTrace, setUpProtocol, setWarn, startDownHandler, statsEnabled, stopInternal, upThreadEnabled

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

sock

java.net.DatagramSocket sock

Socket used for

sending unicast packets and
receiving unicast packets

The address of this socket will be our local address (local_addr)

last_ports_used

private static org.jgroups.util.BoundedList last_ports_used

BoundedList of the last 100 ports used. This is to avoid reusing a port for DatagramSocket

num_last_ports

int num_last_ports

Maintain a list of local ports opened by DatagramSocket. If this is 0, this option is turned off. If bind_port is > 0, then this option will be ignored

mcast_recv_sock

java.net.MulticastSocket mcast_recv_sock

IP multicast socket for receiving multicast packets

mcast_send_sock

java.net.MulticastSocket mcast_send_sock

IP multicast socket for sending multicast packets

mcast_send_sockets

java.net.MulticastSocket[] mcast_send_sockets

If we have multiple mcast send sockets, e.g. send_interfaces or send_on_all_interfaces enabled

tos

int tos

Traffic class for sending unicast and multicast datagrams. Valid values are (check #DatagramSocket.setTrafficClass(int) for details):

IPTOS_LOWCOST (0x02), decimal 2
IPTOS_RELIABILITY (0x04)<, decimal 4/LI>
IPTOS_THROUGHPUT (0x08), decimal 8
IPTOS_LOWDELAY (0x10), decimal 16

mcast_addr

org.jgroups.stack.IpAddress mcast_addr

The multicast address (mcast address and port) this member uses

mcast_addr_name

java.lang.String mcast_addr_name

The multicast address used for sending and receiving packets

mcast_port

int mcast_port

The multicast port used for sending and receiving packets

mcast_receiver

java.lang.Thread mcast_receiver

The multicast receiver thread

ucast_receiver

UDP.UcastReceiver ucast_receiver

The unicast receiver thread

ip_mcast

boolean ip_mcast

Whether to enable IP multicasting. If false, multiple unicast datagram packets are sent rather than one multicast packet

ip_ttl

int ip_ttl

The time-to-live (TTL) for multicast datagram packets

mcast_send_buf_size

int mcast_send_buf_size

Send buffer size of the multicast datagram socket

mcast_recv_buf_size

int mcast_recv_buf_size

Receive buffer size of the multicast datagram socket

ucast_send_buf_size

int ucast_send_buf_size

Send buffer size of the unicast datagram socket

ucast_recv_buf_size

int ucast_recv_buf_size

Receive buffer size of the unicast datagram socket

Constructor Detail

UDP

public UDP()

Creates the UDP protocol, and initializes the state variables, does however not start any sockets or threads.

Method Detail

setProperties

public boolean setProperties(java.util.Properties props)

Setup the Protocol instance acording to the configuration string. The following properties are read by the UDP protocol:

param mcast_addr - the multicast address to use default is 228.8.8.8
param mcast_port - (int) the port that the multicast is sent on default is 7600
param ip_mcast - (boolean) flag whether to use IP multicast - default is true
param ip_ttl - Set the default time-to-live for multicast packets sent out on this socket. default is 32

Overrides:: setProperties in class TP

getLastPortsUsed

private org.jgroups.util.BoundedList getLastPortsUsed()

run

public void run()

Description copied from interface: java.lang.Runnable

This method will be called by whoever wishes to run your class implementing Runnable. Note that there are no restrictions on what you are allowed to do in the run method, except that you cannot throw a checked exception.

Specified by:: run in interface java.lang.Runnable

getInfo

public java.lang.String getInfo()

Specified by:: getInfo in class TP

sendToAllMembers

public void sendToAllMembers(byte[] data,
                             int offset,
                             int length)
                      throws java.lang.Exception

Description copied from class: TP

Send to all members in the group. UDP would use an IP multicast message, whereas TCP would send N messages, one for each member

Specified by:: sendToAllMembers in class TP

sendToSingleMember

public void sendToSingleMember(org.jgroups.Address dest,
                               byte[] data,
                               int offset,
                               int length)
                        throws java.lang.Exception

Description copied from class: TP

Send to all members in the group. UDP would use an IP multicast message, whereas TCP would send N messages, one for each member

Specified by:: sendToSingleMember in class TP

postUnmarshalling

public void postUnmarshalling(org.jgroups.Message msg,
                              org.jgroups.Address dest,
                              org.jgroups.Address src,
                              boolean multicast)

Specified by:: postUnmarshalling in class TP

postUnmarshallingList

public void postUnmarshallingList(org.jgroups.Message msg,
                                  org.jgroups.Address dest,
                                  boolean multicast)

Specified by:: postUnmarshallingList in class TP

_send

private void _send(java.net.InetAddress dest,
                   int port,
                   boolean mcast,
                   byte[] data,
                   int offset,
                   int length)
            throws java.lang.Exception

getName

public java.lang.String getName()

start

public void start()
           throws java.lang.Exception

Creates the unicast and multicast sockets and starts the unicast and multicast receiver threads

Overrides:: start in class TP

stop

public void stop()

Description copied from class: org.jgroups.stack.Protocol

This method is called on a Channel.disconnect()>Channel.disconnect() 55 . Stops work (e.g. by closing multicast socket). Will be called from top to bottom. This means that at the time of the method invocation the neighbor protocol below is still working. This method will replace the STOP, STOP_OK, CLEANUP and CLEANUP_OK events. The ProtocolStack guarantees that when this method is called all messages in the down queue will have been flushed

Overrides:: stop in class TP

createSockets

private void createSockets()
                    throws java.lang.Exception

Create UDP sender and receiver sockets. Currently there are 2 sockets (sending and receiving). This is due to Linux's non-BSD compatibility in the JDK port (see DESIGN).

bindToInterfaces

private void bindToInterfaces(java.util.List interfaces,
                              java.net.MulticastSocket s,
                              java.net.InetAddress mcastAddr)
                       throws java.io.IOException

createEphemeralDatagramSocket

private java.net.DatagramSocket createEphemeralDatagramSocket()
                                                       throws java.net.SocketException

Creates a DatagramSocket with a random port. Because in certain operating systems, ports are reused, we keep a list of the n last used ports, and avoid port reuse

createDatagramSocketWithBindPort

private java.net.DatagramSocket createDatagramSocketWithBindPort()
                                                          throws java.lang.Exception

Creates a DatagramSocket when bind_port > 0. Attempts to allocate the socket with port == bind_port, and increments until it finds a valid port, or until port_range has been exceeded

dumpSocketInfo

private java.lang.String dumpSocketInfo()
                                 throws java.lang.Exception

setBufferSizes

void setBufferSizes()

setBufferSize

private void setBufferSize(java.net.DatagramSocket sock,
                           int send_buf_size,
                           int recv_buf_size)

closeSockets

void closeSockets()

Closed UDP unicast and multicast sockets

closeMulticastSocket

void closeMulticastSocket()

closeSocket

private void closeSocket()

startThreads

void startThreads()
            throws java.lang.Exception

Starts the unicast and multicast receiver threads

stopThreads

void stopThreads()

Stops unicast and multicast receiver threads

handleConfigEvent

protected void handleConfigEvent(java.util.HashMap map)

Overrides:: handleConfigEvent in class TP