src/Transport/Discovery/Multicast/MulticastDiscoveryAgent.cs (262 lines of code) (raw):
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
using System;
using System.Collections.Generic;
using System.Net;
using System.Net.Sockets;
using System.Threading;
using Apache.NMS.Util;
using Apache.NMS.ActiveMQ.Threads;
using Apache.NMS.ActiveMQ.Transport.Tcp;
using Apache.NMS.ActiveMQ.Commands;
namespace Apache.NMS.ActiveMQ.Transport.Discovery.Multicast
{
internal class MulticastDiscoveryAgent : AbstractDiscoveryAgent
{
public const string DEFAULT_DISCOVERY_URI_STRING = "multicast://239.255.2.3:6155";
public const string DEFAULT_HOST_STR = "default";
public const string DEFAULT_HOST_IP = "239.255.2.3";
public const int DEFAULT_PORT = 6155;
private const string TYPE_SUFFIX = "ActiveMQ-4.";
private const string ALIVE = "alive";
private const string DEAD = "dead";
private const char DELIMITER = '%';
private const int BUFF_SIZE = 8192;
private const int DEFAULT_IDLE_TIME = 500;
private const string DEFAULT_GROUP = "default";
private const int MAX_SOCKET_CONNECTION_RETRY_ATTEMPS = 3;
private const int SOCKET_CONNECTION_BACKOFF_TIME = 500;
private int timeToLive = 1;
private string group = DEFAULT_GROUP;
private bool loopBackMode;
private long keepAliveInterval = DEFAULT_IDLE_TIME;
private string mcInterface;
private string mcNetworkInterface;
private string mcJoinNetworkInterface;
private Socket multicastSocket;
private IPEndPoint endPoint;
#region Property Setters and Getters
public bool LoopBackMode
{
get { return this.loopBackMode; }
set { this.loopBackMode = value; }
}
public int TimeToLive
{
get { return this.timeToLive; }
set { this.timeToLive = value; }
}
public string Interface
{
get { return this.mcInterface; }
set { this.mcInterface = value; }
}
public string NetworkInterface
{
get { return this.mcNetworkInterface; }
set { this.mcNetworkInterface = value; }
}
public string JoinNetworkInterface
{
get { return this.mcJoinNetworkInterface; }
set { this.mcJoinNetworkInterface = value; }
}
public string Type
{
get { return this.group + "." + TYPE_SUFFIX; }
}
public override long KeepAliveInterval
{
get { return this.keepAliveInterval; }
set { this.keepAliveInterval = value; }
}
#endregion
public override String ToString()
{
return "MulticastDiscoveryAgent-" + (SelfService != null ? "advertise:" + SelfService : "");
}
protected override void DoStartAgent()
{
if (String.IsNullOrEmpty(group))
{
throw new IOException("You must specify a group to discover");
}
String type = Type;
if (!type.EndsWith("."))
{
Tracer.Warn("The type '" + type + "' should end with '.' to be a valid Discovery type");
type += ".";
}
if (DiscoveryURI == null)
{
DiscoveryURI = new Uri(DEFAULT_DISCOVERY_URI_STRING);
}
if (Tracer.IsDebugEnabled)
{
Tracer.Debug("start - discoveryURI = " + DiscoveryURI);
}
String targetHost = DiscoveryURI.Host;
int targetPort = DiscoveryURI.Port;
if (DEFAULT_HOST_STR.Equals(targetHost))
{
targetHost = DEFAULT_HOST_IP;
}
if (targetPort < 0)
{
targetPort = DEFAULT_PORT;
}
if (Tracer.IsDebugEnabled)
{
Tracer.DebugFormat("start - myHost = {0}", targetHost);
Tracer.DebugFormat("start - myPort = {0}", targetPort);
Tracer.DebugFormat("start - group = {0}", group);
Tracer.DebugFormat("start - interface = {0}", mcInterface);
Tracer.DebugFormat("start - network interface = {0}", mcNetworkInterface);
Tracer.DebugFormat("start - join network interface = {0}", mcJoinNetworkInterface);
}
int numFailedAttempts = 0;
int backoffTime = SOCKET_CONNECTION_BACKOFF_TIME;
Tracer.Info("Connecting to multicast discovery socket.");
while (!TryToConnectSocket(targetHost, targetPort))
{
numFailedAttempts++;
if (numFailedAttempts > MAX_SOCKET_CONNECTION_RETRY_ATTEMPS)
{
throw new ApplicationException(
"Could not open the socket in order to discover advertising brokers.");
}
Thread.Sleep(backoffTime);
backoffTime = (int)(backoffTime * BackOffMultiplier);
}
}
protected override void DoStopAgent()
{
if (multicastSocket != null)
{
multicastSocket.Close();
}
}
private bool TryToConnectSocket(string targetHost, int targetPort)
{
bool hasSucceeded = false;
try
{
multicastSocket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
endPoint = new IPEndPoint(IPAddress.Any, targetPort);
// We have to allow reuse in the multicast socket. Otherwise, we would be unable to
// use multiple clients on the same machine.
multicastSocket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, 1);
multicastSocket.Bind(endPoint);
IPAddress ipaddress;
if(!TcpTransportFactory.TryParseIPAddress(targetHost, out ipaddress))
{
ipaddress = TcpTransportFactory.GetIPAddress(targetHost, AddressFamily.InterNetwork);
if(null == ipaddress)
{
throw new NMSConnectionException("Invalid host address.");
}
}
if (LoopBackMode)
{
multicastSocket.MulticastLoopback = true;
}
if (TimeToLive != 0)
{
multicastSocket.SetSocketOption(SocketOptionLevel.IP,
SocketOptionName.MulticastTimeToLive, timeToLive);
}
if (!String.IsNullOrEmpty(mcJoinNetworkInterface))
{
// TODO figure out how to set this.
throw new NotSupportedException("McJoinNetworkInterface not yet implemented.");
}
else
{
multicastSocket.SetSocketOption(SocketOptionLevel.IP, SocketOptionName.AddMembership,
new MulticastOption(ipaddress, IPAddress.Any));
}
if (!String.IsNullOrEmpty(mcNetworkInterface))
{
// TODO figure out how to set this.
throw new NotSupportedException("McNetworkInterface not yet implemented.");
}
multicastSocket.ReceiveTimeout = (int)keepAliveInterval;
hasSucceeded = true;
}
catch(SocketException)
{
}
return hasSucceeded;
}
protected override void DoDiscovery()
{
byte[] buffer = new byte[BUFF_SIZE];
string receivedInfoRaw;
string receivedInfo;
try
{
int numBytes = multicastSocket.Receive(buffer);
receivedInfoRaw = System.Text.Encoding.UTF8.GetString(buffer, 0, numBytes);
// We have to remove all of the null bytes if there are any otherwise we just
// take the whole string as is.
if (receivedInfoRaw.IndexOf("\0") != -1)
{
receivedInfo = receivedInfoRaw.Substring(0, receivedInfoRaw.IndexOf("\0"));
}
else
{
receivedInfo = receivedInfoRaw;
}
ProcessServiceAdvertisement(receivedInfo);
}
catch (SocketException)
{
// There was no multicast message sent before the timeout expired...Let us try again.
}
}
protected override void DoAdvertizeSelf()
{
if (!String.IsNullOrEmpty(SelfService))
{
String payload = Type;
payload += started.Value ? ALIVE : DEAD;
payload += DELIMITER + "localhost" + DELIMITER;
payload += SelfService;
byte[] data = System.Text.Encoding.UTF8.GetBytes(payload);
multicastSocket.Send(data);
}
}
private void ProcessServiceAdvertisement(string message)
{
string payload;
string brokerName;
string serviceName;
if (message.StartsWith(Type))
{
payload = message.Substring(Type.Length);
brokerName = GetBrokerName(payload);
serviceName = GetServiceName(payload);
if (payload.StartsWith(ALIVE))
{
ProcessLiveService(brokerName, serviceName);
}
else if (payload.StartsWith(DEAD))
{
ProcessDeadService(serviceName);
}
else
{
// Malformed Payload
}
}
}
private static string GetBrokerName(string payload)
{
string[] results = payload.Split(DELIMITER);
if (results.Length >= 2)
{
return results[1];
}
return null;
}
private static string GetServiceName(string payload)
{
string[] results = payload.Split(DELIMITER);
if (results.Length >= 3)
{
return results[2];
}
return null;
}
}
}