diff --git a/assignments/ReportingForDuty.md b/assignments/ReportingForDuty.md index 89a999c82e2e502c09bc1e983039c5fe9df847ff..e5426929e08967b1567fb7456039e80834003ec7 100644 --- a/assignments/ReportingForDuty.md +++ b/assignments/ReportingForDuty.md @@ -1,6 +1,6 @@ ## Reporting For Duty -Everyone in the course is hereby requested to make a change to this file. This confirms your ability to use Netbeans and your gitlab.nps.edu account. +Everyone in the course is hereby requested to make a change to this file. This confirms your ability to use NetBeans and your gitlab.nps.edu account. Be sure to *git update* before, and be sure to *git commit* and *git push* after! @@ -18,6 +18,14 @@ More information on your use of Git is in the parent directory [README.md](../.. - Dom Hittner +- Nick Hittner + +- Matt Robinson + +- Alex Fisher + +--John Morris + ### 2020 - Bernd Weissenberger diff --git a/assignments/src/MV3500Cohort2020JulySeptember/homework1/FisherTest.java b/assignments/src/MV3500Cohort2020JulySeptember/homework1/FisherTest.java deleted file mode 100644 index 7f6ae6655e8b7de8cde5e55abb8bd48b9b19bfaf..0000000000000000000000000000000000000000 --- a/assignments/src/MV3500Cohort2020JulySeptember/homework1/FisherTest.java +++ /dev/null @@ -1,50 +0,0 @@ -/* Copyright (c) 1995-2020 held by the author(s). All rights reserved. - -Redistribution and use in source and binary forms, with or without -modification, are permitted provided that the following conditions -are met: - - * Redistributions of source code must retain the above copyright - notice, this list of conditions and the following disclaimer. - * Redistributions in binary form must reproduce the above copyright - notice, this list of conditions and the following disclaimer - in the documentation and/or other materials provided with the - distribution. - * Neither the names of the Naval Postgraduate School (NPS) - Modeling Virtual Environments and Simulation (MOVES) Institute - (https://www.nps.edu and https://my.nps.edu/web/moves) - nor the names of its contributors may be used to endorse or - promote products derived from this software without specific - prior written permission. - -THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS -"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT -LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS -FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE -COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, -INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, -BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; -LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER -CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT -LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN -ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE -POSSIBILITY OF SUCH DAMAGE.*/ - -package MV3500Cohort2020JulySeptember.homework1; - -/** - * - * @author adfis - */ - - -public class FisherTest { - - /** - * @param args the command line arguments - */ - public static void main(String[] args) { - // TODO code application logic here - } - -} diff --git a/assignments/src/MV3500Cohort2021JulySeptember/homework1/KeevenTCPExample3Client.java b/assignments/src/MV3500Cohort2021JulySeptember/homework1/KeevenTCPExample3Client.java new file mode 100644 index 0000000000000000000000000000000000000000..baa963c2f6dbaebe3157da7c2e9b31a7e1797322 --- /dev/null +++ b/assignments/src/MV3500Cohort2021JulySeptember/homework1/KeevenTCPExample3Client.java @@ -0,0 +1,99 @@ +package MV3500Cohort2021JulySeptember.homework1; + +import java.io.*; +import java.net.*; + +/** + * This is Assignment 1 where I have modified the given code from TCPExample3Client + * -sleep time has been extended to give more time in between loops + * -Initial print line has been altered to reflect assingnment 1 + * -Loop only runs a finite number of times ,10. + * Before, we always used telnet (netcat) to connect to the server. Here we are + * now writing our own program to do the connection. + * + * As you will see, when we run this after we start the server we will see the + * same string telnet printed, sent by the server. The output at the server will + * show different socket pairs for each time the loop iterates. + * + * @author mcgredo + * @author brutzman + */ +public class KeevenTCPExample3Client { + + /** IPv6 String constant for localhost address, similarly IPv4 127.0.0.1 + * @see <a href="https://en.wikipedia.org/wiki/localhost">https://en.wikipedia.org/wiki/localhost</a> + * @see <a href="https://en.wikipedia.org/wiki/IPv6_address">https://en.wikipedia.org/wiki/IPv6_address</a> + */ + public final static String LOCALHOST = "0:0:0:0:0:0:0:1"; + + /** + * Program invocation, execution starts here + * @param args command-line arguments + */ + public static void main(String[] args) throws InterruptedException { + + // Local variables/fields + Socket socket = null; + InputStream is; + Reader isr; + BufferedReader br; + String serverMessage; + int clientLoopCount = 0; + int numbLoops = 10; + + try { + while (clientLoopCount < numbLoops) + { + clientLoopCount++; // increment at beginning of loop for reliability + System.out.println(KeevenTCPExample3Client.class.getName() + " creating socket..."); + + // We request an IP to connect to ("localhost") and + // port number at that IP (2317). This establishes + // a connection to that IP in the form of a Socket + // object; the server uses a ServerSocket to wait for + // connections. + socket = new Socket(LOCALHOST, 2317); // locohost? + + // Now hook everything up (i.e. set up the streams), Java style: + is = socket.getInputStream(); + isr = new InputStreamReader(is); + br = new BufferedReader(isr); + + // Read a single line written by the server. We'd + // do things a bit differently if there were many lines to be read + // from the server instead of one only. + serverMessage = br.readLine(); + System.out.println("======================Assignment1==========================="); + + System.out.print ("Client loop " + clientLoopCount + ": "); + System.out.println("now we're talking!"); + System.out.println("The message the server sent was: '" + serverMessage + "'"); + // socket gets closed, either automatically/silently by this code (or possibly by the server) + + Thread.sleep(800l); // slow things down, for example 500l (long) = 500 msec + + } // end while(true) // infinite loops are dangerous, be sure to kill this process! + } + catch (IOException e) + { + System.err.println("Problem with " + KeevenTCPExample3Client.class.getName() + " networking:"); // describe what is happening + System.err.println("Error: " + e); + + // Provide more helpful information to user if exception occurs due to running twice at one time + if (e instanceof java.net.BindException) { + System.err.println("*** Be sure to stop any other running instances of programs using this port!"); + } + } + finally // occurs after any other activity when shutting down + { + try { + if (socket != null) + socket.close(); + } catch (IOException e) {} + + // program exit: tell somebody about that happening. Likely cause: server drops connection. + System.out.println(); + System.out.println(KeevenTCPExample3Client.class.getName() + " exit"); + } + } +} diff --git a/assignments/src/MV3500Cohort2021JulySeptember/homework1/KeevenTCPExample3Server.java b/assignments/src/MV3500Cohort2021JulySeptember/homework1/KeevenTCPExample3Server.java new file mode 100644 index 0000000000000000000000000000000000000000..a3423cf6b5fdd89f12ea4e8019ea9c5f61c697b5 --- /dev/null +++ b/assignments/src/MV3500Cohort2021JulySeptember/homework1/KeevenTCPExample3Server.java @@ -0,0 +1,107 @@ +package MV3500Cohort2021JulySeptember.homework1; + +import java.io.*; +import java.net.*; + +/** + * This is Assignment 1 where I have modified the given code from TCPExample3Server + *-server response message changed + * + * Very slightly more complex than example1, further modifying example2. The + * only thing this does differently is introduce a loop into the response, so + * you don't have to restart the program after one response. Also, it prints out + * the socket pair the server sees. Run the program via telnet several times and + * compare the socket pairs. + * + * telnet (nc) localhost 2317 + * + * If you're sophisticated you can contact the instructor's computer while + * running this program. + * + * telnet (nc) [ipNumberOfServerLaptop] 2317 + * + * and have the instructor display the socket pairs received. + * + * @author mcgredo + * @author brutzman + */ +public class KeevenTCPExample3Server { + + /** + * Program invocation, execution starts here + * If already compiled, can run using console in directory ../../build/classes/ by invoking \ + * java -classpath . TcpExamples.TcpExample3Server + * @param args command-line arguments + */ + public static void main(String[] args) { + try { + + // ServerSocket waits for a connection from a client. + // Notice that it is outside the loop; ServerSocket + // needs to be made only once. + System.out.println(KeevenTCPExample3Server.class.getName() + " has started..."); // it helps debugging to put this on console first + + ServerSocket serverSocket = new ServerSocket(2317); + OutputStream os; + PrintStream ps; + InetAddress localAddress, remoteAddress; + int localPort, remotePort; + int serverLoopCount = 0; + + // Server is up and waiting (i.e. "blocked" or paused) + // Loop, infinitely, waiting for client connections. + // Stop the program somewhere else. + while (true) { + + // block until connected to a client + try (Socket clientConnectionSocket = serverSocket.accept()) + { + serverLoopCount++; // increment at beginning of loop for reliability + + // Now hook everything up (i.e. set up the streams), Java style: + os = clientConnectionSocket.getOutputStream(); + ps = new PrintStream(os); + ps.println("This is response " + serverLoopCount + " produced by the server, " + + KeevenTCPExample3Server.class.getName()); // this gets sent back to client! + + // Print some information locally about the Socket connection. + // This includes the port and IP numbers on both sides (the socket pair). + localAddress = clientConnectionSocket.getLocalAddress(); + remoteAddress = clientConnectionSocket.getInetAddress(); + localPort = clientConnectionSocket.getLocalPort(); + remotePort = clientConnectionSocket.getPort(); + + System.out.print ("Server loop " + serverLoopCount + ": "); + + // My socket pair connection looks like this, to localhost: + // Socket pair: (( /0:0:0:0:0:0:0:1, 2317 ), ( /0:0:0:0:0:0:0:1, 54876 )) + // Socket pair: (( /0:0:0:0:0:0:0:1, 2317 ), ( /0:0:0:0:0:0:0:1, 54881 )) + + // Why is the first IP/port the same, while the second set has different ports? + System.out.println(KeevenTCPExample3Server.class.getName() + " socket pair showing host name, address, port:"); + System.out.println(" (( " + + localAddress.getHostName() + "=" + localAddress.getHostAddress() + ", " + localPort + " ), ( " + + remoteAddress.getHostName() + "=" + remoteAddress.getHostAddress() + ", " + remotePort + " ))"); + + if ( localAddress.getHostName().equals( localAddress.getHostAddress()) || + remoteAddress.getHostName().equals(remoteAddress.getHostAddress())) + System.out.println(" note HostName matches address if host has no DNS name"); + + // Notice the use of flush() and try w/ resources. Without + // the try w/ resources the Socket object may stay open for + // a while after the client has stopped needing this + // connection. try w/ resources explicitly ends the connection. + ps.flush(); + // like it or not, you're outta here! + } + } + } catch (IOException e) { + System.err.println("Problem with " + KeevenTCPExample3Server.class.getName() + " networking: " + e); + + // Provide more helpful information to user if exception occurs due to running twice at one time + if (e instanceof java.net.BindException) { + System.err.println("*** Be sure to stop any other running instances of programs using this port!"); + } + } + } +} diff --git a/assignments/src/MV3500Cohort2021JulySeptember/homework1/MorrisTcpExample1Telnet.java b/assignments/src/MV3500Cohort2021JulySeptember/homework1/MorrisTcpExample1Telnet.java new file mode 100644 index 0000000000000000000000000000000000000000..38bbcc2768c17a68917f54b005e31564dbfa7a3d --- /dev/null +++ b/assignments/src/MV3500Cohort2021JulySeptember/homework1/MorrisTcpExample1Telnet.java @@ -0,0 +1,86 @@ +package MV3500Cohort2021JulySeptember.homework1;; + +import java.io.*; +import java.net.*; + +/** + * The simplest possible TCP network program. It listens for + * a connection, from telnet (telnet localhost 2317) or a program + * you write, which we will do later. Right now the TcpExample simply + * writes a string in response to a connection. + * + * Modifying his program is the basis for Assignment 1. + * + * Testing the running server program from telnet looks like this: + * + * it154916:projects mcgredo$ telnet localhost 2317 + * Trying ::1... + * Connected to localhost. + * Escape character is '^]'. + * This was written by the server + * Connection closed by foreign host. + * + * Notice that "This was written by the server" matches + * what is written by the code below, over the output stream. + * + * After this first connection the program below drops out + * the bottom of the program, and does not repeat itself. + * The program exits. + * + * @author mcgredo + * @author brutzman + */ +public class MorrisTcpExample1Telnet +{ + /** + * Program invocation, execution starts here + * @param args command-line arguments + */ + public static void main(String[] args) + { + try + { + System.out.println("TcpExample1Telnet has started and is waiting for a connection."); + System.out.println(" help: https://savage.nps.edu/Savage/developers.html#telnet"); + System.out.println(" enter (telnet localhost 2317) or (nc localhost 2317)..." ); + + // The ServerSocket waits for a connection from a client. + // It returns a Socket object when the connection occurs. + ServerSocket serverSocket = new ServerSocket(2317); + + // Use Java io classes to write text (as opposed to + // unknown bytes of some sort) to the client + + // The Socket object represents the connection between + // the server and client, including a full duplex connection + try (Socket clientConnection = serverSocket.accept()) // wait here for a client to connect + { + // OK we got something, time to respond! + // Use Java io classes to write text (as opposed to + // unknown bytes of some sort) to the client + OutputStream os = clientConnection.getOutputStream(); + PrintStream ps = new PrintStream(os); + + ps.println("This client response was written by Johnny Smiles "); // to remote client + ps.println("MOVES 2021 Cohort is full of badassery."); + System.out.println("This server response was written by Johnny Smiles " ); // to server console + + // "flush()" in important in that it forces a write + // across what is in fact a slow connection + ps.flush(); + } + System.out.println(" completed successfully."); + } + catch(IOException e) + { + System.err.println(" Pardon the interruption, networking issue"); // describe what is happening + System.err.println(e); + // Provide more helpful information to user if exception occurs due to running twice at one time + + // brute force exception checking, can be brittle if exception message changes + // if (e.getMessage().equals("Address already in use: NET_Bind")) + if (e instanceof java.net.BindException) + System.err.println("*** Be sure to stop any other running instances of programs using this port!"); + } + } +} diff --git a/assignments/src/MV3500Cohort2021JulySeptember/homework1/README.md b/assignments/src/MV3500Cohort2021JulySeptember/homework1/README.md index c0f16cb152eac14324694057a50ac035fffc719c..e5bd42a3887286271cc8c591aea01fa2b56f783c 100644 --- a/assignments/src/MV3500Cohort2021JulySeptember/homework1/README.md +++ b/assignments/src/MV3500Cohort2021JulySeptember/homework1/README.md @@ -1,5 +1,7 @@ ## Homework 1: Unicast Networking +Welcome everybody! This is where your homework goes. + Deliverables: * Update unicast sockets sender/receiver, modifying provided code, test via telnet.