9 files changed, 346 insertions, 0 deletions
diff --git a/vnfs/vLB/DNSManager/.DS_Store b/vnfs/vLB/DNSManager/.DS_Store
new file mode 100644
index 00000000..cc896b07
--- /dev/null
+++ b/vnfs/vLB/DNSManager/.DS_Store
diff --git a/vnfs/vLB/DNSManager/LICENSE.TXT b/vnfs/vLB/DNSManager/LICENSE.TXT
new file mode 100644
index 00000000..ae12da20
--- /dev/null
+++ b/vnfs/vLB/DNSManager/LICENSE.TXT
@@ -0,0 +1,22 @@
+/*
+ * ============LICENSE_START==========================================
+ * ===================================================================
+ * Copyright © 2017 AT&T Intellectual Property. All rights reserved.
+ * ===================================================================
+ * Licensed 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.
+ * ============LICENSE_END============================================
+ *
+ * ECOMP and OpenECOMP are trademarks 
+ * and service marks of AT&T Intellectual Property.
+ *
+ */
diff --git a/vnfs/vLB/DNSManager/README.txt b/vnfs/vLB/DNSManager/README.txt
new file mode 100644
index 00000000..4c690dc0
--- /dev/null
+++ b/vnfs/vLB/DNSManager/README.txt
@@ -0,0 +1,17 @@
+README
+---
+
+Run the dnsmembership.sh script before activating DNS clients. dnsmembership.sh starts the DNSMembershipManager Java class, which uses the FDServer Java class to keep track of the remote DNS servers that are currently active. Example:
+
+./dnsmembership.sh
+
+The script will call the DNSMembershipManager binary with default parameters:
+- java DNSMembershipManager [port] [timeout (sec)] [threshold] [debug]
+  - [port]: port where the server listens for incoming packets
+  - [timeout (sec)]: how often update the status of remote processes (clients)
+  - [threshold]: how many missed packet are required to suspect a remote process to be dead
+  - [debug]: verbose mode (TRUE: >=1, FALSE: <=0) 
+- Example: java DNSMembershipManager 8888 10 3 1
+
+Please change the default parameters in the dnsmembership.sh script as appropriate for your configuration.
+  
diff --git a/vnfs/vLB/DNSManager/pom.xml b/vnfs/vLB/DNSManager/pom.xml
new file mode 100644
index 00000000..20287f07
--- /dev/null
+++ b/vnfs/vLB/DNSManager/pom.xml
@@ -0,0 +1,51 @@
+<project>
+
+  <modelVersion>4.0.0</modelVersion>
+  <groupId>org.openecomp.demo.vnf.lb</groupId>
+  <artifactId>dns-manager</artifactId>
+  <name>DNS Manager</name>
+  <packaging>jar</packaging>
+  <version>1.0.0</version>
+
+  <build>
+    <plugins>
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-jar-plugin</artifactId>
+        <version>2.3.2</version>
+        <configuration>
+          <archive>
+            <manifest>
+              <mainClass>main.java.DNSMembershipManager</mainClass>
+            </manifest>
+          </archive>
+        </configuration>
+    </plugin>
+
+    <plugin>
+      <groupId>org.apache.maven.plugins</groupId>
+      <artifactId>maven-deploy-plugin</artifactId>
+        <configuration>
+          <skip>false</skip>
+        </configuration>
+    </plugin>
+
+    <plugin>
+      <groupId>org.apache.maven.plugins</groupId>
+      <artifactId>maven-install-plugin</artifactId>
+      <configuration>
+        <skip>false</skip>
+      </configuration>
+     </plugin>
+    </plugins>
+  </build>
+
+  <distributionManagement>
+      <repository>
+          <id>nexus</id>
+          <name>OpenECOMP Release Repository</name>
+          <url>https://ecomp-nexus:8443/repository/raw</url>
+      </repository>
+  </distributionManagement>
+
+</project>
diff --git a/vnfs/vLB/DNSManager/src/.DS_Store b/vnfs/vLB/DNSManager/src/.DS_Store
new file mode 100644
index 00000000..201b6cf3
--- /dev/null
+++ b/vnfs/vLB/DNSManager/src/.DS_Store
diff --git a/vnfs/vLB/DNSManager/src/main/.DS_Store b/vnfs/vLB/DNSManager/src/main/.DS_Store
new file mode 100644
index 00000000..d0f5e852
--- /dev/null
+++ b/vnfs/vLB/DNSManager/src/main/.DS_Store
diff --git a/vnfs/vLB/DNSManager/src/main/java/.DS_Store b/vnfs/vLB/DNSManager/src/main/java/.DS_Store
new file mode 100644
index 00000000..097132be
--- /dev/null
+++ b/vnfs/vLB/DNSManager/src/main/java/.DS_Store
diff --git a/vnfs/vLB/DNSManager/src/main/java/DNSMembershipManager.java b/vnfs/vLB/DNSManager/src/main/java/DNSMembershipManager.java
new file mode 100644
index 00000000..a597f3e5
--- /dev/null
+++ b/vnfs/vLB/DNSManager/src/main/java/DNSMembershipManager.java
@@ -0,0 +1,95 @@
+
+/*************************************************************************//**
+ *
+ * Copyright © 2017 AT&T Intellectual Property. All rights reserved.
+ *
+ * Licensed 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.
+ *
+ ****************************************************************************/
+
+package main.java;
+
+import java.io.IOException;
+import java.util.HashSet;
+import java.util.Iterator;
+import java.util.Set;
+
+public class DNSMembershipManager {
+	/*
+	 * Uses Failure Detector (FD) to keep track of the DNS servers currently active.
+	 * @param port: the port that the FD service listens for incoming UDP packets
+	 * @param timeout: how often the FD checks the status of client processes
+	 * @param threshold: number of missing ping messages before declaring a client dead
+	 * @param debug: debug mode on/off
+	 */
+	
+	static Set<String> active = new HashSet<String>();
+	
+	@SuppressWarnings("static-access")
+	public static void main(String[] args) throws IOException, InterruptedException {
+		if(args.length != 5) {
+			System.out.println("Missing input parameters");
+			System.out.println("Usage:");
+			System.out.print("\t- java FDServer [public IP address] [port] [timeout (sec)] [threshold] [debug]\n");
+			System.exit(0);
+		}
+		
+		// Input parameters: PORT, TIMEOUT, THRESHOLD
+		String IPADDR = args[0];
+		int PORT = Integer.parseInt(args[1]);
+		long TIMEOUT = Long.parseLong(args[2]) * 1000; // convert the FD timeout to milliseconds
+		int THRESHOLD = Integer.parseInt(args[3]);
+		int debug = Integer.parseInt(args[4]);
+		boolean DEBUG;
+		if(debug <= 0)
+			DEBUG = false;
+		else
+			DEBUG = true;
+		
+		// Start Failure Detector
+		FDServer fd = new FDServer(IPADDR, PORT, TIMEOUT, THRESHOLD, DEBUG);
+		
+		// Check the status of client processes periodically. We use the same timeout value as FD
+		Set<String> active = new HashSet<String>();
+		while(true) {
+			Set<String> alive_this_round = fd.getAliveProcesses();
+			Iterator<String> iter = alive_this_round.iterator();
+			String pid;
+			
+			// Check if there is some new DNS active
+			while(iter.hasNext()) {
+				pid = iter.next();
+				if(!active.contains(pid)) {
+					active.add(pid);
+					// Add the new vDNS to the set of vDNS servers
+					String script = new String("bash /opt/FDserver/add_dns.sh " + pid);
+		            Runtime.getRuntime().exec(script);
+					if(DEBUG) System.out.println("Adding process " + pid + " to the list of DNSs");
+				}
+			}
+			
+			// Remove possible dead DNSs
+			iter = active.iterator();
+			while(iter.hasNext()) {
+				pid = iter.next();
+				if(!alive_this_round.contains(pid)) {
+					iter.remove(); // remove element from the iterator to avoid ConcurrentModificationException
+					// Remove the new vDNS from the set of vDNS servers
+					String script = new String("bash /opt/FDserver/remove_dns.sh " + pid);
+		            Runtime.getRuntime().exec(script);
+					if(DEBUG) System.out.println("Removing process " + pid + " from the list of DNSs");
+				}
+			}
+			Thread.currentThread().sleep(TIMEOUT);
+		}
+	}
+}
diff --git a/vnfs/vLB/DNSManager/src/main/java/FDServer.java b/vnfs/vLB/DNSManager/src/main/java/FDServer.java
new file mode 100644
index 00000000..4b64c584
--- /dev/null
+++ b/vnfs/vLB/DNSManager/src/main/java/FDServer.java
@@ -0,0 +1,161 @@
+
+/*************************************************************************//**
+ *
+ * Copyright © 2017 AT&T Intellectual Property. All rights reserved.
+ *
+ * Licensed 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.
+ *
+ ****************************************************************************/
+
+package main.java;
+
+import java.io.*;
+import java.net.*;
+import java.util.*;
+import java.util.concurrent.ConcurrentHashMap;
+
+/*
+ * Server-side Failure Detector (FD) implementation.
+ * @param port: the port that the FD service listens for incoming UDP packets
+ * @param timeout: how often the FD checks the status of client processes
+ * @param threshold: number of missing ping messages before declaring a client dead
+ * @param debug: debug mode on/off
+ */
+
+public class FDServer implements Runnable {
+	// Input parameters
+	private String IP_ADDR;
+	private int PORT;
+	private long TIMEOUT;
+	private int THRESHOLD;
+	private boolean DEBUG;
+	
+	// Data structures that store information about alive processes, processes alive/dead this round
+	private Map<String, Integer> alive = new ConcurrentHashMap<String, Integer>(); // Key: process IP address; Value: # consecutive missed pings
+	private Set<String> alive_this_round = ConcurrentHashMap.newKeySet(); // Needs to be synchronized because it is accessed by multiple threads
+	private Set<String> dead = new HashSet<String>();
+	
+	public FDServer(String ip_addr, int port, long timeout, int threshold, boolean debug) throws IOException {
+		IP_ADDR = ip_addr;
+		PORT = port;
+		TIMEOUT = timeout;
+		THRESHOLD = threshold;
+		DEBUG = debug;
+		(new Thread(this)).start();
+	}
+	
+	@Override
+	public void run() {
+		try {
+			runFD();
+		} catch (IOException e) {
+			e.printStackTrace();
+		}	
+	}
+	
+	private void runFD() throws IOException {
+		// Check the status of client processes periodically
+		TimerTask timer = new TimerTask() {
+			public void run() {
+				checkClientStatus();
+			}
+		};
+		new Timer().scheduleAtFixedRate(timer, 0, TIMEOUT);
+		
+		// Define a DatagramSocket object for receiving incoming UDP packets
+		@SuppressWarnings("resource")
+		DatagramSocket sock = new DatagramSocket(PORT);
+		byte[] buffer = new byte[256];
+		
+		// Wait for incoming PING messages from remote clients
+		while(true) {
+			DatagramPacket packet = new DatagramPacket(buffer, buffer.length);
+            sock.receive(packet);
+            String[] content = new String(packet.getData()).trim().split(":"); // Remove leading and trailing spaces
+            String msg_type = content[0];
+            String pid = content[1];
+            // Process only PING UDP packets
+            if(msg_type.equals("PING")) {
+            	String ip = packet.getAddress().getHostAddress();
+            	alive_this_round.add(pid);
+				if(DEBUG) System.out.println("Keep-alive message received from process " + pid + " (sender IP Address: " + ip +")");
+				sendReplyMessage(packet.getAddress());
+            }
+            else {
+            	if(DEBUG) System.out.println("The received message is not a PING. Received content: " + content);
+            }
+		}
+	}
+	
+	private void sendReplyMessage(InetAddress address) throws IOException {
+		DatagramSocket sock = new DatagramSocket();
+		// Allocate buffer for the PING message
+		String content = "PONG:" + IP_ADDR;
+		byte[] buffer = content.getBytes();
+		// Sent a PONG message
+		DatagramPacket packet = new DatagramPacket(buffer, buffer.length, address, PORT);
+		sock.send(packet);
+		sock.close();
+	}
+
+	// Update the list of processes that are alive
+	private void checkClientStatus() {
+		if(DEBUG) System.out.println("/================================/");
+		if(DEBUG) System.out.println("Update status of remote processes");
+		// Check if a process alive the previous round is still alive
+		// Otherwise increment its counter
+		Set<String> alive_processes = alive.keySet();
+		Iterator<String> iter = alive_processes.iterator();
+		while(iter.hasNext()) {
+			String process = iter.next();
+			if(!alive_this_round.contains(process)) {
+				int counter = alive.get(process) + 1;
+				alive.put(process, counter);
+				if(DEBUG) System.out.println("Process " + process + " hasn't sent a message " + counter + " time(s) in a row");
+				// If the number of consecutive missed ping messages reached the threshold, 
+				// then assume the process to be dead
+				if(counter == THRESHOLD) {
+					dead.add(process);
+					if(DEBUG) System.out.println("Process " + process + " is dead");
+				}
+			}
+		}
+		
+		// Processes alive this round
+		iter = alive_this_round.iterator();
+		while(iter.hasNext()) {
+			String process = iter.next();
+			alive.put(process, 0);
+			if(DEBUG) System.out.println("Process " + process + " is alive this round");
+		}
+			
+		
+		// Remove dead processes
+		iter = dead.iterator();
+		while(iter.hasNext()) {
+			String process = iter.next();
+			if(alive.containsKey(process))
+				alive.remove(process);
+			if(DEBUG) System.out.println("Process " + process + " is removed from the list of alive processes");
+		}
+		
+		// Cleanup
+		alive_this_round.clear();
+		dead.clear();
+		if(DEBUG) System.out.println();
+	}
+	
+	// Return the set of alive processes to up-stream applications
+	public Set<String> getAliveProcesses() {
+		return alive.keySet();
+	}
+}