add comments [final Project 1 submission]

Author: aneesh-joshi

.gitignore

@@ -0,0 +1,7 @@
+out/
+idea/
+*iml
+
+# for docker created files (?)
+.bash_history
+.viminfo

.idea/workspace.xml

@@ -0,0 +1,32 @@
+#
+# Ubuntu Dockerfile
+#
+# https://github.com/dockerfile/ubuntu
+#
+
+# Pull base image.
+FROM ubuntu:18.04
+
+# Install.
+RUN \
+  sed -i 's/# \(.*multiverse$\)/\1/g' /etc/apt/sources.list && \
+  apt-get update && \
+  apt-get -y upgrade && \
+  apt-get install -y build-essential && \
+  apt-get install -y software-properties-common && \
+  apt-get install -y byobu curl git htop man unzip vim wget && \
+  apt install -y default-jre && \
+  apt install -y iputils-ping && \
+  apt install -y tcpdump && \
+  apt install -y default-jdk && \
+  apt install -y iptables && \
+  rm -rf /var/lib/apt/lists/* 
+
+# Set environment variables.
+ENV HOME /root
+
+# Define working directory.
+WORKDIR /root
+
+# Define default command.
+CMD ["bash"]

Dockerfile

@@ -0,0 +1,3 @@
+docker run -it -v /home/aneeshj/RIT/Sem2/FCN/RIP2:/root/  fcn_docker /bin/bash
+
+docker run -it -v /home/aneeshj/RIT/Sem2/FCN/RIP2:/root/  fcn_docker /bin/bash

log.txt

@@ -58,6 +58,9 @@ class ArgumentParser {
         }
     }
 
+    /**
+     * Displays the help in case an incorrect argument list is passed
+     */
     void displayHelp(){
         System.out.println("DESCRIPTION :\n Initializes a Rover on a given multicast ip, port and with a given id\n" +
                 "USAGE :\n " +

src/ArgumentParser.java

@@ -32,14 +32,14 @@ static byte[] getRIPPacket(byte command, byte roverId, Map<InetAddress, RoutingT
         int packetOffset = 8;
         for (RoutingTableEntry entry : entries.values()) {
             // Add IP entry
-            packetOffset = addIpAddress(ripPacket, packetOffset, entry.ipAddress, entry);
+            packetOffset = addIpAddress(ripPacket, packetOffset, entry.ipAddress);
             packetOffset += 3; // skip the first 3 bytes since they will be
             // 0 and the subnet mask will at max be 32
 
             ripPacket[packetOffset] = entry.subnetMask;
             packetOffset += 1;
 
-            packetOffset = addIpAddress(ripPacket, packetOffset, entry.nextHop, entry);
+            packetOffset = addIpAddress(ripPacket, packetOffset, entry.nextHop);
 
             packetOffset += 3; // skip the first 3 bytes since they will be
             // 0 and the metric will at max be 15
@@ -49,7 +49,15 @@ static byte[] getRIPPacket(byte command, byte roverId, Map<InetAddress, RoutingT
         return ripPacket;
     }
 
-    public static List<RoutingTableEntry> decodeRIPPacket(byte[] packet, int packetLength) throws UnknownHostException{
+    /**
+     * Decode the byte representation of a string into a list of routing table entries
+     *
+     * @param packet       the byte array representing the packet
+     * @param packetLength the length of the payload in the packet
+     * @return a list of routing table entries
+     * @throws UnknownHostException
+     */
+    public static List<RoutingTableEntry> decodeRIPPacket(byte[] packet, int packetLength) throws UnknownHostException {
         int totalEntries = (packetLength - 8) / 16;
         List<RoutingTableEntry> list = new ArrayList<>();
         RoutingTableEntry entry;
@@ -72,8 +80,14 @@ public static List<RoutingTableEntry> decodeRIPPacket(byte[] packet, int packetL
         return list;
     }
 
-
-    private static InetAddress getIpFromPacket(byte[] packet, int offset) throws UnknownHostException{
+    /**
+     * Returns the IP address as extracted from the packet
+     * @param packet the byte array representing the packet
+     * @param offset the offset from which to check
+     * @return the IP starting from the given offset
+     * @throws UnknownHostException
+     */
+    private static InetAddress getIpFromPacket(byte[] packet, int offset) throws UnknownHostException {
         StringBuilder res = new StringBuilder();
         for (int i = 0; i < 4; i++) {
             res.append(getNextNBytes(packet, offset + i, 1) + (i == 3 ? "" : "."));
@@ -97,15 +111,36 @@ private static String getNextNBytes(byte[] packet, int offset, int N) {
         return "" + res;
     }
 
-
-    private static int addIpAddress(byte[] ripPacket, int packetOffset, InetAddress ipToAdd, RoutingTableEntry entry) {
+    /**
+     * Adds the ip to the packet
+     * @param ripPacket the rip packet
+     * @param packetOffset the offset from which to start filling
+     * @param ipToAdd the ip which has to be added
+     * @return
+     */
+    private static int addIpAddress(byte[] ripPacket, int packetOffset, InetAddress ipToAdd) {
         for (byte ipSubPart : ipToAdd.getAddress()) {
             ripPacket[packetOffset] = ipSubPart;
             packetOffset += 1;
         }
         return packetOffset;
     }
 
+    /**
+     * Prints the hex dump of the packet
+     * @param ripByteRepresentation the byte representation of the rip packet
+     */
+    private static void printPacket(byte[] ripByteRepresentation) {
+        for (int i = 0; i < ripByteRepresentation.length; i += 1) {
+            System.out.printf("%02x" + ((i + 1) % 4 == 0 ? "\n" : "  -- "), ripByteRepresentation[i]);
+        }
+    }
+
+    /**
+     * Main function which tests the utility
+     * @param args arguments passed to the main function
+     * @throws Exception
+     */
     public static void main(String[] args) throws Exception {
         // Test for RIP packet util
         RoutingTableEntry packet = new RoutingTableEntry(InetAddress.getByName("255.255.255.255"),
@@ -117,16 +152,11 @@ public static void main(String[] args) throws Exception {
         Map<InetAddress, RoutingTableEntry> routingTableEntries = new HashMap<>();
         routingTableEntries.put(InetAddress.getByName("255.255.255.255"), packet);
         routingTableEntries.put(InetAddress.getByName("123.221.1.55"), packet1);
-        byte[] ripByteRepresentation = getRIPPacket((byte) 1, (byte)12, routingTableEntries);
+        byte[] ripByteRepresentation = getRIPPacket((byte) 1, (byte) 12, routingTableEntries);
 
         printPacket(ripByteRepresentation);
 
         System.out.println(decodeRIPPacket(ripByteRepresentation, ripByteRepresentation.length));
     }
 
-    private static void printPacket(byte[] ripByteRepresentation) {
-        for (int i = 0; i < ripByteRepresentation.length; i += 1) {
-            System.out.printf("%02x" + ((i + 1) % 4 == 0 ? "\n" : "  -- "), ripByteRepresentation[i]);
-        }
-    }
 }

src/RIPPacketUtil.java

@@ -2,15 +2,26 @@
 import java.net.InetAddress;
 import java.util.TimerTask;
 
+/**
+ * A timer task for when a Rover goes down
+ */
 public class RouterDeathTimerTask extends TimerTask {
     InetAddress routerIp;
     Rover rover;
 
+    /**
+     * Constructs a timer task for rover death
+     * @param rover the Rover object running the timer
+     * @param routerIp the ip of the rover which is being checked
+     */
     RouterDeathTimerTask(Rover rover, InetAddress routerIp){
         this.routerIp = routerIp;
         this.rover = rover;
     }
 
+    /**
+     * Task which is run on the timer running out
+     */
     @Override
     public void run() {
         try {

src/RouterDeathTimerTask.java

@@ -28,28 +28,33 @@ public class RoutingTableEntry{
     }
 
     /**
-     * Empty constructor which allows manual setting of member varaibles.
+     * Empty constructor which allows manual setting of member variables.
      */
     RoutingTableEntry(){
 
     }
 
+    /**
+     * Returns a string representation of the routing table entry
+     * @return string representation of the routing table entry
+     */
     @Override
     public String toString(){
 
         StringBuilder res = new StringBuilder();
-        res.append("\n");
-        res.append(ipAddress).append("/").append(subnetMask).append(" \t");
-        res.append(nextHop + " \t");
+        res.append(ipAddress.toString().substring(1)).append("/").append(subnetMask).append(" \t");
+        res.append(nextHop.toString().substring(1) + " \t");
         res.append(metric + " \t");
-//        res.append("IP Address : " + ipAddress + "\t");
-//        res.append("Subnet Mask : " + subnetMask + "\t");
-//        res.append("Next Hop : " + nextHop + "\t");
-//        res.append("Metric : " + metric + "\t");
+
 
         return res.toString();
     }
 
+    /**
+     * Checks whether 2 entries are the same.
+     * @param otherObject the object to check equality with
+     * @return true if the other object is equal to this one, false otherwise
+     */
     @Override
     public boolean equals(Object otherObject) {
         if(!(otherObject instanceof RoutingTableEntry)){