vnfs/vLB/DNSClient/src/main/java/DNSServer.java

   1
   2 /*************************************************************************//**
   3  *
   4  * Copyright © 2017 AT&T Intellectual Property. All rights reserved.
   5  *
   6  * Licensed under the Apache License, Version 2.0 (the "License");
   7  * you may not use this file except in compliance with the License.
   8  * You may obtain a copy of the License at
   9  *        http://www.apache.org/licenses/LICENSE-2.0
  10  *
  11  * Unless required by applicable law or agreed to in writing, software
  12  * distributed under the License is distributed on an "AS IS" BASIS,
  13  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  14  * See the License for the specific language governing permissions and
  15  * limitations under the License.
  16  *
  17  ****************************************************************************/
  18
  19 package main.java;
  20
  21 import java.io.IOException;
  22 import java.net.DatagramPacket;
  23 import java.net.DatagramSocket;
  24
  25 /*
  26  * Client-side Failure Detector (FD) implementation.
  27  * @param server_addr: IP address of the remote server
  28  * @param port: the port that the FD service listens for incoming UDP packets
  29  * @param timeout: how often the FD checks the status of client processes
  30  * @param debug: debug mode on/off
  31  */
  32
  33 public class DNSServer {
  34
  35         public static void main(String[] args) throws IOException {
  36                 if(args.length != 5) {
  37                         System.out.println("Missing input parameters");
  38                         System.out.println("Usage:");
  39                         System.out.print("\t- java FDClient [process ID] [server IP address] [server port] [timeout (sec)] [debug]\n");
  40                         System.exit(0);
  41                 }
  42                 // IP address and port of the remote server
  43                 String PID = args[0];
  44                 String SERVER_ADDR = args[1];
  45                 int PORT = Integer.parseInt(args[2]);
  46                 long TIMEOUT = Long.parseLong(args[3]) * 1000; // convert the FD timeout to milliseconds
  47                 int debug = Integer.parseInt(args[4]);
  48                 boolean DEBUG;
  49                 if(debug <= 0)
  50                         DEBUG = false;
  51                 else
  52                         DEBUG = true;
  53
  54                 // Run FD client
  55                 new FDClient(PID, SERVER_ADDR, PORT, TIMEOUT, DEBUG);
  56
  57                 // Listen for reply messages
  58                 @SuppressWarnings("resource")
  59                 DatagramSocket sock = new DatagramSocket(PORT);
  60                 byte[] buffer = new byte[256];
  61                 boolean gre_tunnel_enabled = false;
  62
  63                 while(true) {
  64                         DatagramPacket packet = new DatagramPacket(buffer, buffer.length);
  65             sock.receive(packet);
  66             String[] content = new String(packet.getData()).trim().split(":"); // Remove leading and trailing spaces
  67             String msg_type = content[0];
  68             String ip = content[1];
  69             // Process only PING UDP packets
  70             if(msg_type.equals("PONG")) {
  71                                 if(DEBUG) System.out.println("Reply message received from process " + ip);
  72                                 if(!gre_tunnel_enabled) {
  73                                         // Set GRE tunnel towards load balancer
  74                                         String script = new String("bash /opt/FDclient/set_gre_tunnel.sh " + ip);
  75                             Runtime.getRuntime().exec(script);
  76                                         if(DEBUG) System.out.println("GRE tunnel towards load balancer " + ip + " done");
  77                                         gre_tunnel_enabled = true;
  78                                 }
  79             }
  80             else {
  81                 if(DEBUG) System.out.println("The received message is not a PONG. Received content: " + content);
  82             }
  83                 }
  84         }
  85 }