commit bb2db4e7174b0bd91d5e0ddfd5f3c0dae7965d0d Author: gasc Date: Sun Aug 22 13:22:37 2021 +0200 Importation du code depuis GitHub diff --git a/LICENSE b/LICENSE new file mode 100644 index 0000000..f288702 --- /dev/null +++ b/LICENSE @@ -0,0 +1,674 @@ + GNU GENERAL PUBLIC LICENSE + Version 3, 29 June 2007 + + Copyright (C) 2007 Free Software Foundation, Inc. + Everyone is permitted to copy and distribute verbatim copies + of this license document, but changing it is not allowed. + + Preamble + + The GNU General Public License is a free, copyleft license for +software and other kinds of works. + + The licenses for most software and other practical works are designed +to take away your freedom to share and change the works. By contrast, +the GNU General Public License is intended to guarantee your freedom to +share and change all versions of a program--to make sure it remains free +software for all its users. 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If your program is a subroutine library, you +may consider it more useful to permit linking proprietary applications with +the library. If this is what you want to do, use the GNU Lesser General +Public License instead of this License. But first, please read +. diff --git a/README.md b/README.md new file mode 100644 index 0000000..4b5ae97 --- /dev/null +++ b/README.md @@ -0,0 +1,18 @@ +# TDTS06NetworkCourse +Sharing my labs done during TDTS06 course at Linköping University (HT2020). + +## Lab 2 +Very basic web proxy supporting multi-threading. The proxy intentionally alters certain texts and images. Only supporting HTTP. + +### Configuration +Example of proxy configuration under firefox. The procedure is broadly similar for other browsers. +Go to preferences, go to the bottom of the General page, find "network options" and enter the following parameters: +``` +Proxy HTTP: 127.0.0.1 Port: 8080 +Proxy HTTPS: 127.0.0.1 Port: 8080 +Hôte SOCKS: 127.0.0.1 Port: 8080 +``` + +## Lab 4 +Implementation of `RouterNode.java`. You will need the lab environnement to run the simulation. There is also a bash script useful for build and run the simulation. + diff --git a/lab2/proxy.py b/lab2/proxy.py new file mode 100755 index 0000000..bbad059 --- /dev/null +++ b/lab2/proxy.py @@ -0,0 +1,253 @@ +#!/usr/bin/env python3 +# -*- coding: utf-8 -*- + +""" + TDTS06 - Computer networks 2020/21 + Last modification: 2020-10-02 (rev 3) + First release: 2020-09-25 (rev 1) + + Websites to try our very basic proxy: + http://zebroid.ida.liu.se/fakenews/test2.html + http://zebroid.ida.liu.se/fakenews/test4.html + + Note to the corrector: + """ """ comments are used to describe the general operation of a passage + while # comments describe the operation of a particular line. + + Usage: proxy.py [-h] [--debug] [--port PORT] + + Optional arguments: + -h, --help show the help message and exit + --debug print debug information + --port PORT set the port to use for the client side connection + +""" + + +import argparse # For program's argument management +import re # To find patterns +import signal # To implement a signal handler +import socket # A low level socket programming library +import time # To manage timeout +import _thread # Library for multi-threading + + +""" Proxy general parameters (default values) """ +HOST = '127.0.0.1' # Localhost +INTERNAL_PORT = 8080 # HTTP proxy internal port (can be change by user using --port PORT) +EXTERNAL_PORT = 80 # Port for server connection + +""" Alteration parameters """ +REPLACE1 = "Trolly" +REPLACE2 = "Linköping" +PATTERN1 = re.compile("Smiley", re.IGNORECASE) +PATTERN2 = re.compile("Stockholm", re.IGNORECASE) + +""" Dev. parameters """ +DEBUG = False # Can be change by passing --debug arg + + +""" A non-blocking recv function """ +def recv_non_blocking(socket): + total_data = [] + first_pkt = True + content_length = 0 + + while True: + # Try to receive data + try: + print("Receiving data segment...") + data = socket.recv(8192) + + # Trying to find the Content_Length field + if first_pkt: + first_pkt = False + pos = data.find(b'Content-Length:') + pos_end = data.find(b'\r', pos, len(data) - 1) + content_length = int(data[pos+16:pos_end].decode("utf-8")) + + # If we have new data, we add it to the total + if data: + total_data.append(data) + # If the total exceed the Content_Length field, we are done. + if len(b''.join(total_data)) >= content_length and content_length: + break + else: + time.sleep(0.05) + # Except no data + except: + pass + return b''.join(total_data) + + +""" +A function which alter a request + This function is particularly complex since it is necessary + to replace words by others while ensuring that these + replaced words are not image addresses. +""" +def altered(request): + try: + # Decoding the request to analyse it + altered_request = request.decode("utf-8") + except UnicodeDecodeError: + return request + + """ + The purpose of this part is to remplace 'Smiley' by 'Trolly' + and 'Stockholm' by 'Linköping' everywhere except in image names. + """ + final_request = "" + tmp = "" + analyse_start = 0 + r_end = len(altered_request) - 1 + # Searching for image + img_pos = altered_request.find('<', analyse_start, r_end) + while img_pos > -1: + # We alter until the start of + final_request += PATTERN2.sub(REPLACE2, PATTERN1.sub(REPLACE1, altered_request[analyse_start:img_pos])) + + analyse_start = altered_request.find('>', img_pos, r_end) + # We do not modify the inside of + final_request += altered_request[img_pos:analyse_start] + # We search for another image + img_pos = altered_request.find('<', analyse_start, r_end) + + # We alter the end of the request + final_request += PATTERN2.sub(REPLACE2, PATTERN1.sub(REPLACE1, altered_request[analyse_start:img_pos])) + return bytes(final_request, "utf-8") + + +""" A basic SIGINT handler""" +def signal_handler(sig, frame): + print('Stopping...') + try: + # Try closing client socket + client_socket.close() + except NameError: + pass + try: + # Try closing server socket + server_socket.close() + except NameError: + pass + + exit(0) + + +def send_server(t_url, t_protocol, t_server, t_client_connection): + """ Attempt to resend the request to the server """ + print("Trying to reach the website:") + server_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM) + server_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) + t_server_ip = socket.gethostbyname(t_server) + server_socket.connect((t_server_ip, EXTERNAL_PORT)) + print("Connected to server...") + print("Sending request...") + new_request = bytes("GET " + t_url + " " + t_protocol + "\nHost: " + t_server + "\r\n\r\n", "utf-8") + server_socket.sendall(new_request) + + """ Waiting fo response """ + print("Request sent.") + server_response = recv_non_blocking(server_socket) + #server_response = recv_timeout(server_socket) + print("Response from the server.") + + """ Request analysis """ + status_code = server_response[:25].decode("utf-8").split("\n")[0].split(' ')[1] + if status_code != "200": + print("The server returned an error, status code: ", status_code) + print("Error bypass attempt...") + + """ Text alteration """ + print("Server response alteration") + server_response = altered(server_response) + + """ We just resend the altered server response to the client """ + print("Transmitting the altered response to the client") + t_client_connection.sendall(server_response) + server_socket.close() + + # DEBUG + if DEBUG: + print("") + print("DEBUG:") + print(data) + print(new_request) + print(server_response) + print("") + # END DEBUG + + +def manage_request(data, client_connection): + """ Analysis of the request and identification """ + request = data.decode("utf-8").split("\n") + header = request[0].split(' ') + method = header[0] + + if "detectportal.firefox.com/success.txt" in request: + pass + elif method == "GET": + """ If it is a GET request, we extract any useful information """ + url = header[1] + server = url.split('/')[2] + server_ip = socket.gethostbyname(server) + protocol = header[2] + print("Interception of a GET method requesting the URL: ", url) + print("Destination server: ", server, " (", server_ip, ")") + + """ Image alteration """ + print("Checking for alteration...") + if "smiley.jpg" in url: + url = "http://zebroid.ida.liu.se/fakenews/trolly.jpg" + + _thread.start_new_thread(send_server, (url, protocol, server, client_connection)) + + """ If this is not a GET request """ + else: + print("Receiving an unsupported method: ", method) + if DEBUG: + print("") + print("DEBUG:") + print(data) + print("") + + +""" Code entry """ +""" We check for arguments """ +parser = argparse.ArgumentParser(description='A very basic HTTP proxy.') +parser.add_argument('--debug', help='print debug information', action='store_true') +parser.add_argument('--port', help='set the port to use for the client side connection') +args = parser.parse_args() +if args.debug: + DEBUG = True +if args.port: + INTERNAL_PORT = int(args.port) + + +""" Starting proxy initialisation """ +print("Init proxy...") +# Launching signal handler +signal.signal(signal.SIGINT, signal_handler) +if DEBUG: + print("DEBUG: Debug mode enabled.") + + +""" We create a local proxy on the port INTERNAL_PORT and we listen, waiting for a request """ +client_socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM) +client_socket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1) +client_socket.bind((HOST, INTERNAL_PORT)) + + +while True: + client_socket.listen() + print("Proxy ready and waiting...") + + """ We accept any connection on the port and we keep the data sent """ + client_connection, addr = client_socket.accept() + print("Connected by", addr) + print("Receiving data...") + data = client_connection.recv(2048) + + _thread.start_new_thread(manage_request, (data, client_connection)) + diff --git a/lab2/user_manual_v1.pdf b/lab2/user_manual_v1.pdf new file mode 100644 index 0000000..4ba2c21 Binary files /dev/null and b/lab2/user_manual_v1.pdf differ diff --git a/lab4/RouterNode.java b/lab4/RouterNode.java new file mode 100644 index 0000000..4ab975d --- /dev/null +++ b/lab4/RouterNode.java @@ -0,0 +1,207 @@ +import javax.swing.*; +import java.util.Arrays; + +public class RouterNode { + private int myID; + private GuiTextArea myGUI; + private RouterSimulator sim; + private int[] costs = new int[RouterSimulator.NUM_NODES]; + private int[] routesCosts = new int[RouterSimulator.NUM_NODES]; + private int[] routesList = new int[RouterSimulator.NUM_NODES]; + private int[][] distanceTable = new int[RouterSimulator.NUM_NODES][RouterSimulator.NUM_NODES]; + + // Program parameters + private int CONST_TAB_SIZE = 12; // Constant used to set column width + private boolean POISONED_REVERSE = true; // To set poisoned reverse or not + + /* TDTS06 - Lab 4 */ + + + //-------------------------------------------------- + // Virtual router constructor, init. base values, distance table, routes table & costs table + public RouterNode(int ID, RouterSimulator sim, int[] costs) { + myID = ID; + this.sim = sim; + myGUI = new GuiTextArea(" Output window for Router #"+ ID + " "); + + System.arraycopy(costs, 0, this.costs, 0, RouterSimulator.NUM_NODES); + System.arraycopy(costs, 0, this.routesCosts, 0, RouterSimulator.NUM_NODES); + + + // Route list initialisation + for (int i = 0; i < sim.NUM_NODES; i++) { + // If the cost is not infinity, we have a route + if (costs[i] != sim.INFINITY){routesList[i] = i;} + else{routesList[i] = -1;} + } + + // Distance table initialisation: + // Infinity everywhere... + for (int[] row: distanceTable) {Arrays.fill(row, sim.INFINITY);} + // ...except for itself + distanceTable[myID] = Arrays.copyOf(costs, costs.length); + + // Sending first update to neighbour + sendUpdate(); + + // Printing first distance table + printDistanceTable(); + } + + + //-------------------------------------------------- + // Update the route list from the distanceTable + private boolean Update() { + // We are going to check for update to avoid sending useless info. + boolean updt = false; + for (int i = 0; i < sim.NUM_NODES; i++) { + // We ignore ourself + if (i == myID) {continue;} + + int newRouteCost = sim.INFINITY; + + // We keep the old values in memory + int oldRoute = routesList[i]; + int oldRouteCost = distanceTable[myID][i]; + + for (int j = 0; j < sim.NUM_NODES; j++){ + // We keep ignoring ourself + if (j == myID) {continue;} + + // If this is a neighbour AND if the new searched route is greater than the actual distance AND if it is not us + if(costs[j] != RouterSimulator.INFINITY && newRouteCost > distanceTable[j][i] + costs[j] && j != myID){ + distanceTable[myID][i] = distanceTable[j][i] + costs[j]; + newRouteCost = distanceTable[myID][i]; + routesList[i] = j; + routesCosts[i] = newRouteCost; + } + } + // If we have changed smth then we have a update + if(oldRoute != routesList[i] || oldRouteCost != distanceTable[myID][i]){ + updt = true; + } + } + return updt; + } + + + //-------------------------------------------------- + public void recvUpdate(RouterPacket pkt) { + DEBUG("Rcv packet !"); + // Updating the distance table + distanceTable[pkt.sourceid] = pkt.mincost; + // Updating the routes list from the distance table + // and send this update to all neighbour if there + // are changes + if (Update()) {sendUpdate();} + } + + + //-------------------------------------------------- + private void sendUpdate() { + for (int i = 0; i < sim.NUM_NODES; i++) { + int[] sendedCosts = Arrays.copyOf(distanceTable[myID],sim.NUM_NODES); + + // We ignore non-neighbor nodes + if(i == myID || costs[i] == sim.INFINITY) {continue;} + + // Implementing poisoned reverse + if(POISONED_REVERSE) { + // For all destination nodes, if our route for a other node go thought + // this destination node, we set the distance to infinity to avoid that + // this destination node try to go back thought us and create a loop. + // See page 418 in the course book (4th edition). + for (int j = 0; j < RouterSimulator.NUM_NODES; j++) { + if (routesList[j] == i && j != i) { + sendedCosts[j] = RouterSimulator.INFINITY; + } + } + } + RouterPacket pkt = new RouterPacket(myID,i,sendedCosts); + DEBUG("Sending updt !"); + sim.toLayer2(pkt); + } + } + + //-------------------------------------------------- + // Function that print a table header + private void printTabHeader() { + myGUI.print(F.format("dst",CONST_TAB_SIZE) + " |"); + for (int i = 0; i < sim.NUM_NODES ; i++) {myGUI.print(F.format(i,CONST_TAB_SIZE));} + myGUI.println(""); + for (int i = 0; i < sim.NUM_NODES ; i++) { + for (int j = 0; j <= 1.5*CONST_TAB_SIZE; j++) { + myGUI.print("-"); + } + } + myGUI.println(""); + } + + //-------------------------------------------------- + // Print distance table, costs list & routes list when call + public void printDistanceTable() { + // Header + myGUI.println("Current table for " + myID + + " at time " + sim.getClocktime()); + + // DistanceTable + myGUI.println("Distancetable: "); + printTabHeader(); + + // Printing a line for each known routers + for (int i = 0; i < sim.NUM_NODES; ++i ) { + // We ignore non-neighbor nodes + if (costs[i] == sim.INFINITY) continue; + + myGUI.print(F.format("nbr " + i, CONST_TAB_SIZE) + "|"); + for (int j = 0; j < sim.NUM_NODES; ++j ) {myGUI.print(F.format(distanceTable[i][j],CONST_TAB_SIZE));} + myGUI.println(""); + } + myGUI.println(""); + + // Distance vector & routes + myGUI.println("Our distance vector and routes: "); + printTabHeader(); + + // Printing costs + myGUI.print(F.format("cost",CONST_TAB_SIZE) + "|"); + for (int i = 0; i < sim.NUM_NODES; i++) { + myGUI.print(F.format(routesCosts[i],CONST_TAB_SIZE)); + //myGUI.print(F.format(costs[i],CONST_TAB_SIZE)); + } + myGUI.println(""); + + // Printing routes + myGUI.print(F.format("route",CONST_TAB_SIZE) + "|"); + for (int i = 0; i < sim.NUM_NODES; i++) { + myGUI.print(F.format(routesList[i],CONST_TAB_SIZE)); + } + myGUI.println(""); + + // Printing info on poisoned reverse + if (POISONED_REVERSE) { + myGUI.println("(Poisoned reverse active)"); + } + else { + myGUI.println("(No poisoned reverse)"); + } + myGUI.println("\n"); + } + + //-------------------------------------------------- + // If a link change its cost + public void updateLinkCost(int dest, int newcost) { + // Updating costs list + costs[dest] = newcost; + // Spreading the update + if (Update()) {sendUpdate();} + } + + // DEBUG FUNCTION - TO REMOVE + private void DEBUG(String str) { + //myGUI.print(" DEBUG from " + myID + " at time " + sim.getClocktime() + ": "); + //myGUI.println(str); + } +} + + diff --git a/lab4/run.sh b/lab4/run.sh new file mode 100755 index 0000000..bbd051c --- /dev/null +++ b/lab4/run.sh @@ -0,0 +1,20 @@ +#!/bin/bash + +#set -xv + +echo "Remember to save the file (Ctrl+S) before compiling!" + +rm bin -r > /dev/null 2>&1 +rm *.class > /dev/null 2>&1 + +javac *.java +make test > /dev/null + +rm bin -r > /dev/null 2>&1 +rm *.class > /dev/null 2>&1 + +echo "Done." +exit 0 + + +