10 files changed, 349 insertions, 0 deletions

diff --git a/sem5/net/m7/opg.md b/sem5/net/m7/opg.md
new file mode 100644
index 0000000..546a57a
--- /dev/null
+++ b/sem5/net/m7/opg.md
@@ -0,0 +1,26 @@
+# Opgaver 
+```
+2020-09-29:s5/net/mm7/opg/1 #fbd9
+```
+
+## Opg 1
+
+Få hjælp til den her
+
+## Opg 2
+
+**A)**
+Parking because otherwise the max is 7.
+
+**B)**
+Sniff.
+But the interval should not be 1 hour, to not lose sync.
+
+Parking can also be used, because the client can be set up to sync from beacons.
+
+**C)**
+Hold, so the master can put the client on hold for 5 sec.
+
+## Opg 3
+
+Switching master role at time intervals.
diff --git a/sem5/oop/m7/.classpath b/sem5/oop/m7/.classpath
new file mode 100644
index 0000000..fb50116
--- /dev/null
+++ b/sem5/oop/m7/.classpath
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<classpath>
+	<classpathentry kind="src" path="src"/>
+	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER"/>
+	<classpathentry kind="output" path="bin"/>
+</classpath>
diff --git a/sem5/oop/m7/.gitignore b/sem5/oop/m7/.gitignore
new file mode 100644
index 0000000..ae3c172
--- /dev/null
+++ b/sem5/oop/m7/.gitignore
@@ -0,0 +1 @@
+/bin/
diff --git a/sem5/oop/m7/.project b/sem5/oop/m7/.project
new file mode 100644
index 0000000..771bfe1
--- /dev/null
+++ b/sem5/oop/m7/.project
@@ -0,0 +1,17 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<projectDescription>
+	<name>distchat</name>
+	<comment></comment>
+	<projects>
+	</projects>
+	<buildSpec>
+		<buildCommand>
+			<name>org.eclipse.jdt.core.javabuilder</name>
+			<arguments>
+			</arguments>
+		</buildCommand>
+	</buildSpec>
+	<natures>
+		<nature>org.eclipse.jdt.core.javanature</nature>
+	</natures>
+</projectDescription>
diff --git a/sem5/oop/m7/src/InputHandler.java b/sem5/oop/m7/src/InputHandler.java
new file mode 100644
index 0000000..c6b87d3
--- /dev/null
+++ b/sem5/oop/m7/src/InputHandler.java
@@ -0,0 +1,30 @@
+import java.io.BufferedReader;
+import java.io.InputStreamReader;
+
+public class InputHandler extends Thread {
+	private Node node;
+
+	public InputHandler(Node node) {
+		this.node = node;
+	}
+	
+	public void run() {
+		BufferedReader in = new BufferedReader(new InputStreamReader(System.in));
+		
+		try {
+			String line;
+			while ((line = in.readLine()) != null) {
+				char cmd = line.charAt(0);
+				Message msg = null;
+				if (cmd == '#' || cmd == '!') {
+					msg = new PingMessage(this.node.name, line.substring(1), cmd == '!');
+				} else {
+					msg = new TextMessage(this.node.name, "", line);
+				}
+				this.node.sendMsgLocal(msg);
+			}
+		} catch (Exception e){
+			System.err.printf("Send err: %s%n", e);
+		}
+	}
+}
diff --git a/sem5/oop/m7/src/Main.java b/sem5/oop/m7/src/Main.java
new file mode 100644
index 0000000..d2a1b61
--- /dev/null
+++ b/sem5/oop/m7/src/Main.java
@@ -0,0 +1,20 @@
+public class Main {
+
+	public static void main(String[] args) {
+		System.out.println("YEAH LETS GO");
+
+		try {
+			Node n = new Node(args[0], args[1]);
+			InputHandler h = new InputHandler(n);
+			for (int i = 2; i < args.length; i++) {
+				n.addNeighbor(args[i]);
+			}
+			
+			h.start();
+			n.start();
+		} catch (Exception e) {
+			System.err.printf("Fatal err: %s%n", e);
+		}
+	}
+
+}
\ No newline at end of file
diff --git a/sem5/oop/m7/src/Message.java b/sem5/oop/m7/src/Message.java
new file mode 100644
index 0000000..cad2240
--- /dev/null
+++ b/sem5/oop/m7/src/Message.java
@@ -0,0 +1,34 @@
+import java.io.OutputStream;
+import java.io.ObjectOutputStream;
+import java.io.IOException;
+import java.io.Serializable;
+import java.util.Random;
+
+public class Message implements Serializable {
+	public String from;
+	// If too is empty it is for all
+	public String to;
+	public int id;
+	
+	public Message(String from, String to) {
+		this.from = from;
+		this.to = to;
+	}
+	
+	public void send(OutputStream out) throws IOException{
+		ObjectOutputStream objout = null;
+		try {
+			objout = new ObjectOutputStream(out);
+			objout.writeObject(this);
+		} finally {
+			if (objout != null) {
+				objout.close();
+			}
+		}
+	}
+	
+	public void trace(String node) {}
+	
+	public void handle(Node n) throws Exception {}
+}
+
diff --git a/sem5/oop/m7/src/Node.java b/sem5/oop/m7/src/Node.java
new file mode 100644
index 0000000..2a5d56a
--- /dev/null
+++ b/sem5/oop/m7/src/Node.java
@@ -0,0 +1,155 @@
+import java.net.InetAddress;
+import java.net.UnknownHostException;
+import java.net.ServerSocket;
+import java.net.Socket;
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.concurrent.ThreadLocalRandom;
+import java.util.concurrent.Semaphore;
+
+import java.io.OutputStream;
+import java.io.ObjectInputStream;
+import java.io.InputStream;
+
+class NodeAddr {
+	public int port;
+	public InetAddress addr;
+
+	public NodeAddr(String addr, int port) throws UnknownHostException {
+		this.port = port;
+		this.addr = InetAddress.getByName(addr);
+	}
+
+	public NodeAddr(String fulladdr) throws UnknownHostException {
+		String fields[] = fulladdr.split(":");
+		this.port = Integer.parseInt(fields[1]);
+		this.addr = InetAddress.getByName(fields[0]);
+	}
+}
+
+public class Node {
+	private NodeAddr bind;
+	private ArrayList<NodeAddr> neighbors;
+
+	private HashSet<String> seenMsgs;
+	private Semaphore lock;
+
+	public String name;
+
+	public Node(String bind, String name) throws UnknownHostException {
+		this.bind = new NodeAddr(bind);
+		this.neighbors = new ArrayList<>();
+		this.name = name;
+		this.seenMsgs = new HashSet<>();
+		this.lock = new Semaphore(1);
+	}
+	
+	public void addNeighbor(String addr) throws UnknownHostException {
+		this.neighbors.add(new NodeAddr(addr));
+	}
+
+	public void start() throws IOException {
+		ServerSocket socket = null;
+		try {
+			socket = new ServerSocket(this.bind.port, 50, this.bind.addr);
+
+			while (true) {
+				Socket conn = socket.accept();
+				Handler h = new Handler(conn, this);
+				h.start();
+			}
+		} finally {
+			if (socket != null) {
+				socket.close();
+			}
+		}
+	}
+	
+	public void sendMsgLocal(Message msg) throws Exception {
+		// Kind of hacky but thats how we do it
+		msg.id = ThreadLocalRandom.current().nextInt();
+		
+		if (!this.checkMsg(msg)) {
+			this.sendMsg(msg);
+		}
+	}
+	
+	private boolean checkMsg(Message msg) throws InterruptedException {
+		String msgid = String.format("%s%d", msg.from, msg.id);
+		this.lock.acquire();
+
+		if (this.seenMsgs.contains(msgid)) {
+			this.lock.release();
+			return true;
+		}
+		this.seenMsgs.add(msgid);
+		this.lock.release();
+		return false;
+	}
+
+	private void sendMsg(Message msg) throws Exception {
+		for (NodeAddr n : this.neighbors) {
+			Socket conn = null;
+			OutputStream out = null;
+			try {
+				conn = new Socket(n.addr, n.port);
+				out = conn.getOutputStream();
+
+				msg.send(out);
+
+			} finally {
+				if (conn != null) {
+					conn.close();
+				}
+				if (out != null) {
+					out.close();
+				}
+			}
+		}
+	}
+	
+	public void handleMsg(Message msg) throws Exception {
+		if (this.checkMsg(msg)) {
+			return;
+		}
+		if (!msg.to.equals(this.name)) {
+			msg.trace(this.name);
+
+			// Forward
+			this.sendMsg(msg);
+			
+			if (!msg.to.equals("")) {
+				return;
+			}
+		}
+		
+		msg.handle(this);
+	}
+}
+
+class Handler extends Thread {
+	private Socket conn;
+	private Node node;
+
+	public Handler(Socket conn, Node node) {
+		this.conn = conn;
+		this.node = node;
+	}
+
+	public void run() {
+		InputStream in = null;
+		ObjectInputStream objin = null;
+		try {
+			in = this.conn.getInputStream();
+			objin = new ObjectInputStream(in);
+			Object obj = objin.readObject();
+			if (!(obj instanceof Message)) {
+				throw new Exception("Received object is not a message");
+			}
+			this.node.handleMsg((Message) obj);
+		} catch (Exception e) {
+			System.err.printf("Client err: %s%n", e);
+		}
+	}
+}
\ No newline at end of file
diff --git a/sem5/oop/m7/src/PingMessage.java b/sem5/oop/m7/src/PingMessage.java
new file mode 100644
index 0000000..39a9386
--- /dev/null
+++ b/sem5/oop/m7/src/PingMessage.java
@@ -0,0 +1,46 @@
+import java.io.Serializable;
+import java.util.ArrayList;
+
+public class PingMessage extends Message implements Serializable {
+	private boolean is_response;
+	private boolean do_trace;
+	public ArrayList<String> trace;
+
+	public PingMessage(String from, String to, boolean trace) {
+		super(from, to);
+		this.is_response = false;
+		this.do_trace = trace;
+		if (trace) {
+			this.trace = new ArrayList<>();
+		}
+	}
+	
+	public void trace(String node) {
+		if (!this.do_trace || this.is_response) {
+			return;
+		}
+		System.out.println("DOING TRACE");
+		
+		this.trace.add(node);
+	}
+	
+	public void handle(Node node) throws Exception {
+		if (this.is_response) {
+			System.out.printf("%s >> Ping response%n", this.from);
+			if (this.do_trace) {
+				System.out.print("  Trace: ");
+				for (String t : this.trace) {
+					System.out.printf("%s -> ", t);
+				}
+				System.out.print(System.lineSeparator());
+			}
+			return;
+		}
+
+		this.is_response = true;
+		this.to = this.from;
+		this.from = node.name;
+		
+		node.sendMsgLocal(this);
+	}
+}
diff --git a/sem5/oop/m7/src/TextMessage.java b/sem5/oop/m7/src/TextMessage.java
new file mode 100644
index 0000000..f5f5c74
--- /dev/null
+++ b/sem5/oop/m7/src/TextMessage.java
@@ -0,0 +1,14 @@
+import java.io.Serializable;
+
+public class TextMessage extends Message implements Serializable {
+	private String msg;
+
+	public TextMessage(String from, String to, String msg) {
+		super(from, to);
+		this.msg = msg;
+	}
+	
+	public void handle(Node node) throws Exception {
+		System.out.printf("%s >> %s%n", this.from, this.msg);
+	}
+}