TFTP-ClientServer-Project/Project_Code/ErrorSim.java at master · djhogarth/TFTP-ClientServer-Project · GitHub

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FILENAME - ErrorSim.java

ASSIGNMENT - Final Project - SYSC 3303

AUTHOR - GROUP 3 - W18

DETAILS - A program that will receives DatagramPackets from Client or Server and forwards them to the opposite host.

import java.net.*;

import java.util.Scanner;

import java.util.Timer;

import java.util.TimerTask;

class ErrorSim extends CommonMethods {

private static final int CLIENT_PORT = 23;

private static final int SERVER_PORT = 69;

private static final int DATA_SIZE = 516;

private static DatagramPacket rxPacket, txPacket;

// testmode variables

private static int mode = 0; // 0=normal,1=lose a packet,2=delay a packet,3=duplicate a packet and choose

// when to send it, 4 = illegal packet , 5= unknown TID

private static byte testOpcode = 0; // RRQ,WRQ,DATA,ACK,ERR

private static int testBlockNum = -1; // 0 to 65335 - for lost/delayed/duplicate DATA/ACK

private static long delay = 0; // sleep in milliseconds

private static boolean isLost = false; // is current packet lost

private static DatagramPacket testPacket = null; // used for Duplicate and Illegal packet test modes

private static DatagramSocket testSocket; // used for Unknown TID

private static int illegalField; // chosen field to invalidate: 1 = opcode, 2 = mode, 3 = errorCode, 4 = blockNum

// .... May need to add more

private static byte delayOpcode = 0; // DATA,ACK delayed packet opcode to replace

private static int delayBkNum = 0; // block number to replace

// get user input for test modes

private static void getUserInput() {

boolean inputValid = false;

String input = "";

boolean showMenu = true;

boolean testMode = false;

Scanner reader = new Scanner(System.in); // Reading from System.in

while (showMenu) {

inputValid = false;

while (!inputValid) {

System.out.print("Would you like to run the ErrorSim in (t)est or (n)ormal mode? ");

input = reader.nextLine();

input = input.toLowerCase();

switch (input) {

case "t":

inputValid = true;

showMenu = false;

testMode = true; // testing operation

break;

case "n":

inputValid = true;

showMenu = false;

testMode = false; // normal operation

System.out.println("You've chosen normal operation.\n");

break;

default:

System.out.println("The input is not valid.");

}

if (testMode) {

System.out.print("\nTest Mode Options: \n" + "(1)\t- Lose a Packet\n" + "(2)\t- Delay a Packet\n"

+ "(3)\t- Duplicate a Packet\n" + "(4)\t- Send an Illegal Packet\n"

+ "(5)\t- Send from Unknown TID\n" + "(c)\t- Cancel Test Mode\n");

inputValid = false;

while (!inputValid) {

System.out.print("Please choose an option: ");

input = reader.nextLine();

input = input.toLowerCase();

switch (input) {

case "1":

inputValid = true;

mode = 1;

break;

case "2":

inputValid = true;

mode = 2;

break;

case "3":

inputValid = true;

mode = 3;

break;

case "4":

inputValid = true;

mode = 4;

break;

case "5":

inputValid = true;

mode = 5;

break;

case "c":

inputValid = true;

testMode = false;

System.out.println("You've chosen normal operation.\n");

break;

default:

System.out.println("The input is not valid.");

}

if (mode != 0) {

// 1=lose a packet,2=delay a packet,3=duplicate a packet and choose when to send

// it

inputValid = false;

if (mode == 1) {

System.out.print("\nLosing a Packet! \n");

System.out.print("(1)\t- Read Request\n" + "(2)\t- Write Request\n" + "(3)\t- Data\n"

+ "(4)\t- Acknowledgement\n" + "(5)\t- Error\n\n");

while (!inputValid) {

System.out.print("Which packet type is being dropped? ");

input = reader.nextLine();

input = input.toLowerCase();

switch (input) {

case "1":

inputValid = true;

testOpcode = 1;

System.out.println("The next RRQ will be dropped.\n");

break;

case "2":

inputValid = true;

testOpcode = 2;

System.out.println("The next WRQ will be dropped.\n");

break;

case "3":

inputValid = true;

testOpcode = 3;

break;

case "4":

inputValid = true;

testOpcode = 4;

break;

case "5":

inputValid = true;

testOpcode = 5;

System.out.println("The next ERROR will be dropped.\n");

break;

default:

System.out.println("The input is not valid.");

}

if (testOpcode == 3 || testOpcode == 4) {

inputValid = false;

while (!inputValid) {

System.out.print("What packet/block number would you like to lose? ");

input = reader.nextLine();

int tempNum = -1;

try {

tempNum = Integer.valueOf(input);

if (tempNum > 0) {

inputValid = true;

testBlockNum = tempNum;

}

} catch (Exception e) {

System.out.println("The input is not valid.");

}

if (testOpcode == 3)

System.out.println("DATA Packet# " + testBlockNum + " will be dropped.\n");

if (testOpcode == 4)

System.out.println("ACK Packet# " + testBlockNum + " will be dropped.\n");

}

if (mode == 2) {

System.out.print("\nDelaying a Packet! \n");

System.out.print("(1)\t- Read Request\n" + "(2)\t- Write Request\n" + "(3)\t- Data\n"

+ "(4)\t- Acknowledgement\n" + "(5)\t- Error\n\n");

while (!inputValid) {

System.out.print("Which packet type is being delayed? ");

input = reader.nextLine();

input = input.toLowerCase();

switch (input) {

case "1":

inputValid = true;

testOpcode = 1;

delayOpcode = 1;

break;

case "2":

inputValid = true;

testOpcode = 2;

delayOpcode = 2;

break;

case "3":

inputValid = true;

testOpcode = 3;

delayOpcode = 3;

break;

case "4":

inputValid = true;

testOpcode = 4;

delayOpcode = 4;

break;

case "5":

inputValid = true;

testOpcode = 5;

delayOpcode = 5;

break;

default:

System.out.println("The input is not valid.");

}

if (testOpcode == 3 || testOpcode == 4) {

inputValid = false;

while (!inputValid) {

System.out.print("What packet/block number would you like to delay? ");

input = reader.nextLine();

int tempNum = -1;

try {

tempNum = Integer.valueOf(input);

if (tempNum > 0) {

inputValid = true;

delayBkNum = tempNum;

}

} catch (Exception e) {

System.out.println("The input is not valid.");

}

// Delay Amount

inputValid = false;

while (!inputValid) {

System.out.print("How long will the packet be delayed (in ms)? ");

input = reader.nextLine();

int tempNum = -1;

try {

tempNum = Integer.valueOf(input);

if (tempNum > 0) {

inputValid = true;

delay = tempNum;

}

} catch (Exception e) {

System.out.println("The input is not valid.");

}

if (testOpcode == 1)

System.out.println("RRQ will be delayed by " + delay + " ms.\n");

if (testOpcode == 2)

System.out.println("WRQ will be delayed by " + delay + " ms.\n");

if (testOpcode == 3)

System.out.println("DATA Packet# " + delayBkNum + " will be delayed by " + delay + " ms.\n");

if (testOpcode == 4)

System.out.println("ACK Packet# " + delayBkNum + " will be delayed by " + delay + " ms.\n");

if (testOpcode == 5)

System.out.println("ERROR will be delayed by " + delay + " ms.\n");

}

if (mode == 3) {

System.out.print("\nDuplicating a Packet! \n");

System.out.print("(1)\t- Read Request\n" + "(2)\t- Write Request\n" + "(3)\t- Data\n"

+ "(4)\t- Acknowledgement\n" + "(5)\t- Error\n\n");

while (!inputValid) {

System.out.print("Which packet type is being duplicated? ");

input = reader.nextLine();

input = input.toLowerCase();

switch (input) {

case "1":

inputValid = true;

testOpcode = 1;

break;

case "2":

inputValid = true;

testOpcode = 2;

break;

case "3":

inputValid = true;

testOpcode = 3;

break;

case "4":

inputValid = true;

testOpcode = 4;

break;

case "5":

inputValid = true;

testOpcode = 5;

break;

default:

System.out.println("The input is not valid.");

}

if (testOpcode == 3 || testOpcode == 4) {

inputValid = false;

while (!inputValid) {

System.out.print("What packet/block number would you like to duplicate? ");

input = reader.nextLine();

int tempNum = -1;

try {

tempNum = Integer.valueOf(input);

if (tempNum > 0) {

inputValid = true;

testBlockNum = tempNum;

}

} catch (Exception e) {

System.out.println("The input is not valid.");

}

// Delay Amount

inputValid = false;

while (!inputValid) {

System.out.print("How long will the packet be delayed (in ms)? ");

input = reader.nextLine();

int tempNum = -1;

try {

tempNum = Integer.valueOf(input);

if (tempNum > 0) {

inputValid = true;

delay = tempNum;

}

} catch (Exception e) {

System.out.println("The input is not valid.");

}

if (testOpcode == 1)

System.out.println("RRQ will be re-transmitted after " + delay + " ms.\n");

if (testOpcode == 2)

System.out.println("WRQ will be re-transmitted after " + delay + " ms.\n");

if (testOpcode == 3)

System.out.println(

"DATA Packet# " + testBlockNum + " will be re-transmitted after " + delay + " ms.\n");

if (testOpcode == 4)

System.out.println(

"ACK Packet# " + testBlockNum + " will be re-transmitted after " + delay + " ms.\n");

if (testOpcode == 5)

System.out.println("ERROR will be re-transmitted after " + delay + " ms.\n");

}

if (mode == 4) {// Illegal Packet - choose the packet and choose the field to invalidate

// illegalField; //chosen field to invalidate: 1 = opcode, 2 = mode (only for

// RRQ/WRQ), 3 = errorCode (only for errors), 4 = invalidate structure(replace

// all zeroes) .... May need to add more

System.out.print("\nInvalidating a Packet! \n");

System.out.print("(1)\t- Read Request\n" + "(2)\t- Write Request\n" + "(3)\t- Data\n"

+ "(4)\t- Acknowledgement\n" + "(5)\t- Error\n");

while (!inputValid) {

System.out.print("Which packet type is being invalidated?");

input = reader.nextLine();

input = input.toLowerCase();

switch (input) {

case "1":

inputValid = true;

testOpcode = 1;

break;

case "2":

inputValid = true;

testOpcode = 2;

break;

case "3":

inputValid = true;

testOpcode = 3;

break;

case "4":

inputValid = true;

testOpcode = 4;

break;

case "5":

inputValid = true;

testOpcode = 5;

break;

default:

System.out.println("The input is not valid.");

}

if (testOpcode == 3 || testOpcode == 4) {

inputValid = false;

while (!inputValid) {

System.out.print("What packet/block number would you like to invalidate? ");

input = reader.nextLine();

int tempNum = -1;

try {

tempNum = Integer.valueOf(input);

if (tempNum > 0) {

inputValid = true;

testBlockNum = tempNum;

}

} catch (Exception e) {

System.out.println("The input is not valid.");

}

// illegalField; //chosen field to invalidate: 1 = opcode, 2 = mode (only for

// RRQ/WRQ), 3 = errorCode (only for errors), 4 = invalidate structure(replace

// all zeroes) .... May need to add more

inputValid = false;

while (!inputValid) {

System.out.print("\nFields to Invalidate.\n");

System.out.print("(1)\t- Op Code\n" + "(2)\t- Mode(Only for RRQ/WRQ)\n"

+ "(3)\t- ErrorCode(Only for ERROR)\n" + "(4)\t- Structure\n");

System.out.print("How would you like to invalidate the packet? ");

input = reader.nextLine();

// check that input is valid for the opcode

if (input.equals("2") && (testOpcode != 1 && testOpcode != 2)) {

input = "0";

System.out.print("Simulator can only invalidate mode for RRQ/WRQ. ");

} else if (input.equals("3") && testOpcode != 5) {

input = "0";

System.out.print("Simulator can only invalidate error code for ERROR. ");

}

switch (input) {

case "1":

inputValid = true;

illegalField = 1;

break;

case "2":

inputValid = true;

illegalField = 2;

break;

case "3":

inputValid = true;

illegalField = 3;

break;

case "4":

inputValid = true;

illegalField = 4;

break;

default:

System.out.println("The input is not valid.");

}

if (testOpcode == 1)

System.out.println("The next RRQ will be invalidated.\n");

if (testOpcode == 2)

System.out.println("The next WRQ will be invalidated.\n");

if (testOpcode == 3)

System.out.println("DATA Packet# " + testBlockNum + " will be invalidated.\n");

if (testOpcode == 4)

System.out.println("ACK Packet# " + testBlockNum + " will be invalidated.\n");

if (testOpcode == 5)

System.out.println("The next ERROR will be invalidated.\n");

}

if (mode == 5) {// Unknown TID - choose the packet to send

System.out.print("\nPacket from an unknown TID!\n");

System.out.print("(1)\t- Data\n" + "(2)\t- Acknowledgement\n" + "(3)\t- Error\n\n");

while (!inputValid) {

System.out.print("Which packet type is being sent from an unknown TID? ");

input = reader.nextLine();

input = input.toLowerCase();

switch (input) {

case "1":

inputValid = true;

testOpcode = 3;

break;

case "2":

inputValid = true;

testOpcode = 4;

break;

case "3":

inputValid = true;

testOpcode = 5;

System.out.println("The next ERROR will be sent from an unknown TID.\n");

break;

default:

System.out.println("The input is not valid.");

}

if (testOpcode == 3 || testOpcode == 4) {

inputValid = false;

while (!inputValid) {

System.out.print("What packet/block number would you like to send? ");

input = reader.nextLine();

int tempNum = -1;

try {

tempNum = Integer.valueOf(input);

if (tempNum > 0) {

inputValid = true;

testBlockNum = tempNum;

}

} catch (Exception e) {

System.out.println("The input is not valid.");

}

if (testOpcode == 3)

System.out.println("DATA Packet# " + testBlockNum + " will be sent from an unknown TID.\n");

if (testOpcode == 4)

System.out.println("ACK Packet# " + testBlockNum + " will be sent from an unknown TID.\n");

}

//A method that simulates errors for the server, takes as input the port of the sender thread and server socket

public static boolean simulateServerError(int senderPort,DatagramSocket serverSocket ,boolean verboseOutput) throws Exception {

byte[] rxData = rxPacket.getData();

// --- Test Mode 1: Lost Packet ---//

if (mode == 1 && rxData[1] == testOpcode) {

if (rxData[1] == 1) {// if packet is RRQ

isLost = true;

System.out.println("** Dropped a RRQ! **\n");

} else if (rxData[1] == 2) {// if packet is WRQ

isLost = true;

System.out.println("** Dropped a WRQ! **\n");

} else if (rxData[1] == 5) {// if packet is ERROR

isLost = true;

System.out.println("** Dropped an ERROR! **\n");

} else if (blockNumToBytes(testBlockNum)[0] == rxData[2]

&& blockNumToBytes(testBlockNum)[1] == rxData[3]) {// Otherwise check the block number

isLost = true;

if (rxData[1] == 3)

System.out.println("** Dropped a DATA (Block number " + testBlockNum + ") **\n");

if (rxData[1] == 4)

System.out.println("** Dropped an ACK (Block number " + testBlockNum + ") **\n");

}

// --- Test Mode 2: Delay Packet ---//

if (mode == 2 && rxData[1] == testOpcode) {

if (rxData[1] == 1) {// If RRQ

System.out.println("** Delayed RRQ by " + delay + "ms! **\n");

Thread.sleep(delay);

resetTestVars();

} else if (rxData[1] == 2) {// If WRQ

System.out.println("** Delayed WRQ by " + delay + "ms! **\n");

Thread.sleep(delay);

resetTestVars();

} else if (rxData[1] == 5) {// if ERROR

System.out.println("** Delayed ERROR by " + delay + "ms! **\n");

Thread.sleep(delay);

resetTestVars();

} else if (blockNumToBytes(delayBkNum)[0] == rxData[2]

&& blockNumToBytes(delayBkNum)[1] == rxData[3]) {// Otherwise check the block number

if (rxData[1] == 3)

System.out.println(

"** Delayed DATA (Block number " + delayBkNum + ") by " + delay + "ms! **\n");

if (rxData[1] == 4)

System.out.println(

"** Delayed ACK (Block number " + delayBkNum + ") by " + delay + "ms! **\n");

Thread.sleep(delay);

resetTestVars();

}

// --- Test Mode 3: Duplicate Packet ---//

Timer timer = new Timer();

if (mode == 3 && rxData[1] == testOpcode) {

if (rxData[1] == 1) {// If RRQ

String msg = ("** Re-transmitted RRQ after " + delay + " ms!\n");

timer.schedule(new resendPacket(txPacket, serverSocket, msg, direction.OUT, endhost.SERVER,

verboseOutput), delay);

resetTestVars();

} else if (rxData[1] == 2) {// If WRQ

String msg = ("** Re-transmitted WRQ after " + delay + " ms!\n");

timer.schedule(new resendPacket(txPacket, serverSocket, msg, direction.OUT, endhost.SERVER,

verboseOutput), delay);

resetTestVars();

} else if (rxData[1] == 5) {// if ERROR

String msg = ("** Re-transmitted ERROR after " + delay + " ms!\n");

timer.schedule(new resendPacket(txPacket, serverSocket, msg, direction.OUT, endhost.SERVER,

verboseOutput), delay);

resetTestVars();

} else if (blockNumToBytes(testBlockNum)[0] == rxData[2]

&& blockNumToBytes(testBlockNum)[1] == rxData[3]) {// Otherwise check the block number

if (rxData[1] == 3) {

String msg = ("** Re-transmitted DATA (Block number " + testBlockNum + ") after "

+ delay + "ms! **\n");

timer.schedule(new resendPacket(txPacket, serverSocket, msg, direction.OUT,

endhost.SERVER, verboseOutput), delay);

resetTestVars();

}

if (rxData[1] == 4) {

String msg = ("** Re-transmitted ACK (Block number " + testBlockNum + ") after " + delay

+ "ms! **\n");

timer.schedule(new resendPacket(txPacket, serverSocket, msg, direction.OUT,

endhost.SERVER, verboseOutput), delay);

resetTestVars();

}

// --- Test Mode 4: Illegal Packet ---//

if (mode == 4 && rxData[1] == testOpcode) {

boolean isTestPacket = true;// Flag for checking testPacket opcode

if (rxData[1] == 1) {// If RRQ

System.out.println("** Replacing RRQ packet with illegal packet!\n");

} else if (rxData[1] == 2) {// If WRQ

System.out.println("** Replacing WRQ packet with illegal packet!\n");

} else if (rxData[1] == 5) {// if ERROR

System.out.println("** Replacing ERROR packet with illegal packet!\n");

} else if (blockNumToBytes(testBlockNum)[0] == rxData[2]

&& blockNumToBytes(testBlockNum)[1] == rxData[3]) {// Otherwise check the block number

if (rxData[1] == 3) {

System.out.println("** Replacing DATA (Block number " + testBlockNum

+ ") with illegal packet! **\n");

} else if (rxData[1] == 4) {

System.out.println("** Replacing ACK (Block number " + testBlockNum

+ ") with illegal packet! **\n");

}

} else {

isTestPacket = false;

}

if (isTestPacket) {

// illegalField; //chosen field to invalidate: 1 = opcode, 2 = mode, 3 =

// errorCode, 4 = Replace all zeroes .... May need to add more

if (illegalField == 1) {

rxData[0] = 8;

rxData[1] = 8;

} else if (illegalField == 2) {// invalid mode should only be used for WRQ and RRQ

int i = 2;// get position of mode

while (rxData[i] != 0) {

i++;

}

rxData[i + 1] = -1;// Only need to change one character of mode to invalidate it

} else if (illegalField == 3) {

rxData[2] = 9;

rxData[3] = 9;

} else if (illegalField == 4) {// replace all zeroes with ones

for (int i = 0; i < rxData.length; i++) {

if (rxData[i] == 0)

rxData[i] = 1;

}

txPacket.setData(rxData);

resetTestVars();

}

// --- Test Mode 5: Unknown TID ---//

if (mode == 5 && rxData[1] == testOpcode) {

boolean isTestPacket = true;// Flag for checking testPacket opcode

if (rxData[1] == 1) {// If RRQ

System.out.println("** Sending RRQ packet with unknown TID!\n");

} else if (rxData[1] == 2) {// If WRQ

System.out.println("** Sending WRQ packet with unknown TID!\n");

} else if (rxData[1] == 5) {// if ERROR

System.out.println("** Sending ERROR packet with unknown TID!\n");

} else if (blockNumToBytes(testBlockNum)[0] == rxData[2]

&& blockNumToBytes(testBlockNum)[1] == rxData[3]) {// Otherwise check the block number

if (rxData[1] == 3) {

System.out.println(

"** Sending DATA (Block number " + testBlockNum + ") with unknown TID! **\n");

} else if (rxData[1] == 4) {

System.out.println(

"** Sending ACK (Block number " + testBlockNum + ") with unknown TID! **\n");

}

} else {

isTestPacket = false;

}

if (isTestPacket) {

txPacket.setPort(senderPort);

testSocket.send(txPacket);

outputText(txPacket, direction.OUT, endhost.SERVER, verboseOutput);

resetTestVars();

return true;

}

return false;

}

// Waits to receive packet from Client.java

// Upon receipt, forwards it to Server.java

// Waits to receive packet from Server.java

// Upon receipt, forwards it to Client.java

public static void main(String args[]) throws Exception {

System.out.println("TFTP ErrorSim is running.\n");

DatagramSocket clientSocket;

DatagramSocket serverSocket;

boolean verboseOutput = false;

int tempPort = 0;

int client_port = 0;

InetAddress clientIP;

clientSocket = new DatagramSocket(CLIENT_PORT);

serverSocket = new DatagramSocket();

testSocket = new DatagramSocket();

byte[] rxData = new byte[DATA_SIZE];

boolean lastDataPkt = false;

getUserInput();

while (true) {

try {

rxPacket = new DatagramPacket(rxData, rxData.length);

// --- RECEIVE FROM CLIENT ---///

clientSocket.receive(rxPacket);

rxPacket = resizePacket(rxPacket);

InetSocketAddress temp_add = (InetSocketAddress) rxPacket.getSocketAddress();

clientIP=temp_add.getAddress();

client_port = temp_add.getPort();

if (isRequest(rxPacket))

lastDataPkt = false;

// ---START OF OUT OF BAND MANAGEMENT---//

if (!isOOB(rxPacket)) {

outputText(rxPacket, direction.IN, endhost.CLIENT, verboseOutput);

} else {

lastDataPkt = true;

if (rxPacket.getData()[2] == 0)

verboseOutput = false;

else

verboseOutput = true;

}

// ---END OF OUT OF BAND MANAGEMENT---//

// Send to SERVER listener or last Thread

txPacket = rxPacket;

txPacket.setAddress(InetAddress.getLocalHost());

if (rxData[1] == 1 || rxData[1] == 2 || tempPort == 0) {//send to server if RRQ/WRQ or if there is no previous sender

txPacket.setPort(SERVER_PORT);

} else {

txPacket.setPort(tempPort);

}

if(mode != 0)//ERROR SIM to Server

simulateServerError(tempPort,serverSocket,verboseOutput);

if (!isLost) {// Don't send lost packet

serverSocket.send(txPacket);

}

if (!isOOB(txPacket)) {

if(!isLost)

outputText(txPacket, direction.OUT, endhost.SERVER, verboseOutput);

} else {

lastDataPkt = true;

}

// --- RECEIVE FROM SERVER ---//

if (!lastDataPkt && !isLost) {

boolean needPkt = true;

while (needPkt) {

rxPacket = new DatagramPacket(rxData, rxData.length);

serverSocket.receive(rxPacket);

rxPacket = resizePacket(rxPacket);

outputText(rxPacket, direction.IN, endhost.SERVER, verboseOutput);

needPkt = false;

if (rxPacket.getData().length < 512 && rxData[1] == 3)

lastDataPkt = true;

if (rxData[1] == 3 || rxData[1] == 4) {

tempPort = rxPacket.getPort();

}

// --- Test Mode 1: Lost Packet ---//

if (mode == 1 && rxData[1] == testOpcode) {

if (rxData[1] == 5) {// if packet is ERROR

needPkt = false;// Server request thread terminates after sending error

System.out.println("** Dropped an ERROR! **\n");

isLost = true;

// resetTestVars();

} else if (blockNumToBytes(testBlockNum)[0] == rxData[2]

&& blockNumToBytes(testBlockNum)[1] == rxData[3]) {// Otherwise check the block

// number

needPkt = true;

if (rxData[1] == 3) {

System.out.println("** Dropped a DATA (Block number " + testBlockNum + ") **\n");

}

if (rxData[1] == 4) {

System.out.println("** Dropped an ACK (Block number " + testBlockNum + ") **\n");

}

resetTestVars();

}

// --- Test Mode 2: Delay Packet ---//

if (mode == 2 && rxData[1] == testOpcode) {

if (rxData[1] == 1) {// If RRQ

System.out.println("** Delayed RRQ by " + delay + "ms! **\n");

Thread.sleep(delay);

resetTestVars();

} else if (rxData[1] == 2) {// If WRQ

System.out.println("** Delayed WRQ by " + delay + "ms! **\n");

Thread.sleep(delay);

resetTestVars();

} else if (rxData[1] == 5) {// if ERROR

System.out.println("** Delayed ERROR by " + delay + "ms! **\n");

Thread.sleep(delay);

resetTestVars();

} else if (blockNumToBytes(delayBkNum)[0] == rxData[2]

&& blockNumToBytes(delayBkNum)[1] == rxData[3]) {// Otherwise check the block number

if (rxData[1] == 3)

System.out.println("** Delayed DATA (Block number " + delayBkNum + ") by " + delay

+ "ms! **\n");

if (rxData[1] == 4)

System.out.println("** Delayed ACK (Block number " + delayBkNum + ") by " + delay

+ "ms! **\n");

Thread.sleep(delay);

resetTestVars();

}

// --- Test Mode 3: Duplicate Packet ---//

Timer timer = new Timer();

// Send to CLIENT

txPacket = rxPacket;

txPacket.setAddress(clientIP);

txPacket.setPort(client_port);

if (mode == 3 && rxData[1] == testOpcode) {

if (rxData[1] == 1) {// If RRQ

String msg = ("** Re-transmitted RRQ after " + delay + " ms!\n");

timer.schedule(new resendPacket(txPacket, clientSocket, msg, direction.OUT,

endhost.CLIENT, verboseOutput), delay);

resetTestVars();

} else if (rxData[1] == 2) {// If WRQ

String msg = ("** Re-transmitted WRQ after " + delay + " ms!\n");

timer.schedule(new resendPacket(txPacket, clientSocket, msg, direction.OUT,

endhost.CLIENT, verboseOutput), delay);

resetTestVars();

} else if (rxData[1] == 5) {// if ERROR

String msg = ("** Re-transmitted ERROR after " + delay + " ms!\n");

timer.schedule(new resendPacket(txPacket, clientSocket, msg, direction.OUT,

endhost.CLIENT, verboseOutput), delay);

resetTestVars();

} else if (blockNumToBytes(testBlockNum)[0] == rxData[2]

&& blockNumToBytes(testBlockNum)[1] == rxData[3]) {// Otherwise check the block

// number

if (rxData[1] == 3) {

String msg = ("** Re-transmitted DATA (Block number " + testBlockNum + ") after "

+ delay + "ms! **\n");

timer.schedule(new resendPacket(txPacket, clientSocket, msg, direction.OUT,

endhost.CLIENT, verboseOutput), delay);

resetTestVars();

}

if (rxData[1] == 4) {

String msg = ("** Re-transmitted ACK (Block number " + testBlockNum + ") after "

+ delay + "ms! **\n");

timer.schedule(new resendPacket(txPacket, clientSocket, msg, direction.OUT,

endhost.CLIENT, verboseOutput), delay);

resetTestVars();

}

// --- Test Mode 4: Illegal Packet ---//

if (mode == 4 && rxData[1] == testOpcode) {

boolean isTestPacket = true;// Flag for checking testPacket opcode

if (rxData[1] == 1) {// If RRQ

System.out.println("** Replacing RRQ packet with illegal packet!\n");

} else if (rxData[1] == 2) {// If WRQ

System.out.println("** Replacing WRQ packet with illegal packet!\n");

} else if (rxData[1] == 5) {// if ERROR

System.out.println("** Replacing ERROR packet with illegal packet!\n");

} else if (blockNumToBytes(testBlockNum)[0] == rxData[2]

&& blockNumToBytes(testBlockNum)[1] == rxData[3]) {// Otherwise check the block

// number

if (rxData[1] == 3) {

System.out.println("** Replacing DATA (Block number " + testBlockNum

+ ") with illegal packet! **\n");

} else if (rxData[1] == 4) {

System.out.println("** Replacing ACK (Block number " + testBlockNum

+ ") with illegal packet! **\n");

}

} else {

isTestPacket = false;

}

if (isTestPacket) {

// illegalField; //chosen field to invalidate: 1 = opcode, 2 = mode, 3 =

// errorCode, 4 = Replace all zeroes .... May need to add more

if (illegalField == 1) {

rxData[0] = 9;

rxData[1] = 9;

} else if (illegalField == 2) {// invalid mode should only be used for WRQ and RRQ

int i = 2;// get position of mode

while (rxData[i] != 0) {

i++;

}

rxData[i + 1] = -1;// Only need to change one character of mode to invalidate it

} else if (illegalField == 3) {

rxData[2] = 9;

rxData[3] = 9;

} else if (illegalField == 4) {// replace all zeroes with ones

for (int i = 0; i < rxData.length; i++) {

if (rxData[i] == 0)

rxData[i] = 1;

}

txPacket.setData(rxData);

resetTestVars();

}

// --- Test Mode 5: Unknown TID ---//

if (mode == 5 && rxData[1] == testOpcode) {

boolean isTestPacket = true;// Flag for checking testPacket opcode

if (rxData[1] == 1) {// If RRQ

System.out.println("** Sending RRQ packet with unknown TID!\n");

} else if (rxData[1] == 2) {// If WRQ

System.out.println("** Sending WRQ packet with unknown TID!\n");

} else if (rxData[1] == 5) {// if ERROR

System.out.println("** Sending ERROR packet with unknown TID!\n");

} else if (blockNumToBytes(testBlockNum)[0] == rxData[2]

&& blockNumToBytes(testBlockNum)[1] == rxData[3]) {// Otherwise check the block

// number

if (rxData[1] == 3) {

System.out.println("** Sending DATA (Block number " + testBlockNum

+ ") with unknown TID! **\n");

} else if (rxData[1] == 4) {

System.out.println("** Sending ACK (Block number " + testBlockNum

+ ") with unknown TID! **\n");

}

} else {

isTestPacket = false;

}

if (isTestPacket) {

testSocket.send(txPacket);

outputText(txPacket, direction.OUT, endhost.CLIENT, verboseOutput);

resetTestVars();

if(rxData[1]==4)

isLost=true;

else//for Datas and errors

needPkt = true;

}

if (!isLost) {// Don't send lost packet

clientSocket.send(txPacket);

outputText(txPacket, direction.OUT, endhost.CLIENT, verboseOutput);

} else {

resetTestVars();

}

} else {

if (mode == 1)

resetTestVars();

}

} catch (SocketTimeoutException ste) {

System.out.println("Did not receive a packet from CLIENT or SERVER");

}

public static void resetTestVars() {

// testmode variables

mode = 0; // 0=normal,1=lose a packet,2=delay a packet,3=duplicate a packet and choose

// when to send it

testOpcode = 0; // RRQ,WRQ,DATA,ACK,ERR

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TFTP-ClientServer-Project/Project_Code/ErrorSim.java at master · djhogarth/TFTP-ClientServer-Project · GitHub

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