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  • Disable Win+S Key on Windows 8.1?

    - by Rubistro
    How can the Windows + S keyboard shortcut be disabled on Windows 8.1? I had Win+S mapped to take a screen capture in Windows 8 using Evernote. (not using Windows built-in PrintScr to capture the entire screen): After the update, Win+S always brings up the Search panel: A solution using RegEdit would be fine. I just need it disabled so that other capture programs, such as Evernote and Greenshot can use it (as before, pre-Win 8.1).

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  • How to block own rpcap traffic where tshark is running?

    - by Pankaj Goyal
    Platform :- Fedora 13 32-bit machine RemoteMachine$ ./rpcapd -n ClientMachine$ tshark -w "filename" -i "any interface name" As soon as capture starts without any capture filter, thousands of packets get captured. Rpcapd binds to 2002 port by default and while establishing the connection it sends a randomly chosen port number to the client for further communication. Both client and server machines exchange tcp packets through randomly chosen ports. So, I cannot even specify the capture filter to block this rpcap related tcp traffic. Wireshark & tshark for Windows have an option "Do not capture own Rpcap Traffic" in Remote Settings in Edit Interface Dialog box. But there is no such option in tshark for linux. It will be also better if anyone can tell me how wireshark blocks rpcap traffic....

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  • Update: GTAS and EBS

    - by jeffrey.waterman
    Provided below are updated target date timeframes for provided patches for upcoming legislative enhancements.   Dates have been pushed out from previous dates provided due to changes in Treasury mandatory dates.  Mandatory dates for GTAS and IPAC have changes since previous target dates for patches were provided.   These are target dates, not commitments to deliver functionality. Deliverable Target Timeframes for Customer Patches Comments R12 GTAS Configuration Apr 2012 Patch is available GTAS Key Processes Oct/Nov 2012 Includes GTAS processes necessary to create the GTAS interface file, migration of FACTS balances to GTAS, GTAS Trial Balance, and GTAS Transaction Register. GTAS Reports Nov/Dec 2012 GTAS Trial Balance GTAS Transaction Register Capture of Trading Partner TAS/BETC Apr/May 2013 Includes modification necessary to capture BETC, Trading Partner TAS/BETC on relevant transactions. GTAS Other Processes May/Jun  2013 Includes GTAS Customer and Vendor  update processes. IPAC Aug/Sep Includes modification required to IPAC to accommodate Componentized TAS and BETC. 11i GTAS Configuration May 2012 Patch is available GTAS Key Processes Nov/Dec 2012 Includes GTAS processes necessary to create the GTAS interface file, migration of FACTS balances to GTAS, GTAS Trial Balance, and GTAS Transaction Register. GTAS Reports Dec/Jan 2012 GTAS Trial Balance GTAS Transaction Register Capture of Trading Partner TAS/BETC May/Jun 2013 Includes modification necessary to capture BETC, Trading Partner TAS/BETC on relevant transactions. GTAS Other Processes Jun/Jul 2013 Includes GTAS Customer and Vendor  update processes. IPAC Sep/Oct 2013 Includes modification required to IPAC to accommodate Componentized TAS and BETC.

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  • IP address spoofing using Source Routing

    - by iamrohitbanga
    With IP options we can specify the route we want an IP packet to take while connecting to a server. If we know that a particular server provides some extra functionality based on the IP address can we not utilize this by spoofing an IP packet so that the source IP address is the privileged IP address and one of the hosts on the Source Routing is our own. So if the privileged IP address is x1 and server IP address is x2 and my own IP address is x3. I send a packet from x1 to x2 which is supposed to pass through x3. x1 does not actually send the packet. It is just that x2 thinks the packet came from x1 via x3. Now in response if x2 uses the same routing policy (as a matter of courtesy to x1) then all packets would be received by x3. Will the destination typically use the same IP address sequences as specified in the routing header so that packets coming from the server pass through my IP where I can get the required information? Can we not spoof a TCP connection in the above case? Is this attack used in practice?

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  • How to save image drawn on a JPanel?

    - by swift
    I have a panel with transparent background which i use to draw an image. now problem here is when i draw anything on panel and save the image as a JPEG file its saving the image with black background but i want it to be saved as same, as i draw on the panel. what should be done for this? plz guide me j Client.java public class Client extends Thread { static DatagramSocket datasocket; static DatagramSocket socket; Point point; Whiteboard board; Virtualboard virtualboard; JLayeredPane layerpane; BufferedImage image; public Client(DatagramSocket datasocket) { Client.datasocket=datasocket; } //This function is responsible to connect to the server public static void connect() { try { socket=new DatagramSocket (9000); //client connection socket port= 9000 datasocket=new DatagramSocket (9005); //client data socket port= 9002 ByteArrayOutputStream baos=new ByteArrayOutputStream(); DataOutputStream dos=new DataOutputStream(baos); //this is to tell server that this is a connection request dos.writeChar('c'); dos.close(); byte[]data=baos.toByteArray(); //Server IP address InetAddress ip=InetAddress.getByName("10.123.97.154"); //create the UDP packet DatagramPacket packet=new DatagramPacket(data, data.length,ip , 8000); socket.send(packet); Client client=new Client(datasocket); client.createFrame(); client.run(); } catch(Exception e) { e.printStackTrace(); } } //This function is to create the JFrame public void createFrame() { JFrame frame=new JFrame("Whiteboard"); frame.setVisible(true); frame.setBackground(Color.black); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setSize(680,501); frame.addWindowListener(new WindowAdapter() { public void windowOpened(WindowEvent e) {} public void windowClosing(WindowEvent e) { close(); } }); layerpane=frame.getLayeredPane(); board= new Whiteboard(datasocket); image = new BufferedImage(590,463, BufferedImage.TYPE_INT_ARGB); board.setBounds(74,2,590,463); board.setImage(image); virtualboard=new Virtualboard(); virtualboard.setImage(image); virtualboard.setBounds(74,2,590,463); layerpane.add(virtualboard,new Integer(2));//Panel where remote user draws layerpane.add(board,new Integer(3)); layerpane.add(board.colourButtons(),new Integer(1)); layerpane.add(board.shapeButtons(),new Integer(0)); //frame.add(paper.addButtons(),BorderLayout.WEST); } /* * This function is overridden from the thread class * This function listens for incoming packets from the server * which contains the points drawn by the other client */ public void run () { while (true) { try { byte[] buffer = new byte[512]; DatagramPacket packet = new DatagramPacket(buffer, buffer.length); datasocket.receive(packet); InputStream in=new ByteArrayInputStream(packet.getData(), packet.getOffset(),packet.getLength()); DataInputStream din=new DataInputStream(in); int x=din.readInt(); int y=din.readInt(); String varname=din.readLine(); String var[]=varname.split("-",4); point=new Point(x,y); virtualboard.addPoint(point, var[0], var[1],var[2],var[3]); } catch (IOException ex) { ex.printStackTrace(); } } } //This function is to broadcast the newly drawn point to the server public void broadcast (Point p,String varname,String shape,String event, String color) { try { ByteArrayOutputStream baos=new ByteArrayOutputStream(); DataOutputStream dos=new DataOutputStream(baos); dos.writeInt(p.x); dos.writeInt(p.y); dos.writeBytes(varname); dos.writeBytes("-"); dos.writeBytes(shape); dos.writeBytes("-"); dos.writeBytes(event); dos.writeBytes("-"); dos.writeBytes(color); dos.close(); byte[]data=baos.toByteArray(); InetAddress ip=InetAddress.getByName("10.123.97.154"); DatagramPacket packet=new DatagramPacket(data, data.length,ip , 8002); datasocket.send(packet); } catch (Exception e) { e.printStackTrace(); } } //This function is to close the client's connection with the server public void close() { try { ByteArrayOutputStream baos=new ByteArrayOutputStream(); DataOutputStream dos=new DataOutputStream(baos); //This is to tell server that this is request to remove the client dos.writeChar('r'); dos.close(); byte[]data=baos.toByteArray(); //Server IP address InetAddress ip=InetAddress.getByName("10.123.97.154"); DatagramPacket packet=new DatagramPacket(data, data.length,ip , 8000); socket.send(packet); System.out.println("closed"); } catch(Exception e) { e.printStackTrace(); } } public static void main(String[] args) throws Exception { connect(); } } Whiteboard.java class Whiteboard extends JPanel implements MouseListener,MouseMotionListener,ActionListener,KeyListener { BufferedImage image; Boolean tooltip=false; int post; String shape; String selectedcolor="black"; Color color=Color.black; //Color color=Color.white; Point start; Point end; Point mp; Point tip; int keycode; String fillshape; Point fillstart=new Point(); Point fillend=new Point(); int noofside; Button r=new Button("rect"); Button rectangle=new Button("rect"); Button line=new Button("line"); Button roundrect=new Button("roundrect"); Button polygon=new Button("poly"); Button text=new Button("text"); JButton save=new JButton("Save"); Button elipse=new Button("elipse"); ImageIcon fillicon=new ImageIcon("images/fill.jpg"); JButton fill=new JButton(fillicon); ImageIcon erasericon=new ImageIcon("images/eraser.gif"); JButton erase=new JButton(erasericon); JButton[] colourbutton=new JButton[28]; String selected; Point label; String key=""; int ex,ey;//eraser DatagramSocket dataSocket; JButton button = new JButton("test"); Client client; Boolean first; int w,h; public Whiteboard(DatagramSocket dataSocket) { try { UIManager.setLookAndFeel( UIManager.getCrossPlatformLookAndFeelClassName()); } catch (Exception e) { e.printStackTrace(); } setLayout(null); setOpaque(false); setBackground(new Color(237,237,237)); this.dataSocket=dataSocket; client=new Client(dataSocket); addKeyListener(this); addMouseListener(this); addMouseMotionListener(this); setBorder(BorderFactory.createLineBorder(Color.black)); } public void paintComponent(Graphics g) { try { super.paintComponent(g); g.drawImage(image, 0, 0, this); Graphics2D g2 = (Graphics2D)g; if(color!=null) g2.setPaint(color); if(start!=null && end!=null) { if(selected==("elipse")) g2.drawOval(start.x, start.y,(end.x-start.x),(end.y-start.y)); else if(selected==("rect")) g2.drawRect(start.x, start.y, (end.x-start.x),(end.y-start.y)); else if(selected==("rrect")) g2.drawRoundRect(start.x, start.y, (end.x-start.x),(end.y-start.y),11,11); else if(selected==("line")) g2.drawLine(start.x,start.y,end.x,end.y); else if(selected==("poly")) { g2.drawLine(start.x,start.y,end.x,end.y); client.broadcast(start, "start", "poly", "drag", selectedcolor); client.broadcast(end, "end", "poly", "drag", selectedcolor); } } if(tooltip==true) { System.out.println(selected); if(selected=="text") { g2.drawString("|", tip.x, tip.y-5); g2.drawString("Click to add text", tip.x+10, tip.y+23); g2.drawString("__", label.x+post, label.y); } if(selected=="erase") { g2.setPaint(new Color(237,237,237)); g2.fillRect(tip.x-10,tip.y-10,10,10); g2.setPaint(color); g2.drawRect(tip.x-10,tip.y-10,10,10); } } } catch(Exception e) {} } //Function to draw the shape on image public void draw() { Graphics2D g2 = (Graphics2D) image.createGraphics(); Font font=new Font("Times New Roman",Font.PLAIN,14); g2.setFont(font); g2.setPaint(color); if(start!=null && end!=null) { if(selected=="line") g2.drawLine(start.x, start.y, end.x, end.y); else if(selected=="elipse") g2.drawOval(start.x, start.y, (end.x-start.x),(end.y-start.y)); else if(selected=="rect") g2.drawRect(start.x, start.y, (end.x-start.x),(end.y-start.y)); else if(selected==("rrect")) g2.drawRoundRect(start.x, start.y, (end.x-start.x),(end.y-start.y),11,11); else if(selected==("poly")) { g2.drawLine(start.x,start.y,end.x,end.y); client.broadcast(start, "start", "poly", "release", selectedcolor); client.broadcast(end, "end", "poly", "release", selectedcolor); } fillstart=start; fillend=end; fillshape=selected; } if(selected!="poly") { start=null; end=null; } if(label!=null) { if(selected==("text")) { g2.drawString(key,label.x,label.y); client.broadcast(label, key, "text", "release", selectedcolor); } } repaint(); g2.dispose(); } //Function which provides the erase functionality public void erase() { Graphics2D pic=(Graphics2D) image.createGraphics(); Color erasecolor=new Color(237,237,237); pic.setPaint(erasecolor); if(start!=null) pic.fillRect(start.x-10, start.y-10, 10, 10); } //To set the size of the image public void setImage(BufferedImage image) { this.image = image; } //Function to add buttons into the panel, calling this function returns a panel public JPanel shapeButtons() { JPanel shape=new JPanel(); shape.setBackground(new Color(181, 197, 210)); shape.setLayout(new GridLayout(5,2,2,4)); shape.setBounds(0, 2, 74, 166); rectangle.addActionListener(this); rectangle.setToolTipText("Rectangle"); line.addActionListener( this); line.setToolTipText("Line"); erase.addActionListener(this); erase.setToolTipText("Eraser"); roundrect.addActionListener(this); roundrect.setToolTipText("Round edge Rectangle"); polygon.addActionListener(this); polygon.setToolTipText("Polygon"); text.addActionListener(this); text.setToolTipText("Text"); fill.addActionListener(this); fill.setToolTipText("Fill with colour"); elipse.addActionListener(this); elipse.setToolTipText("Elipse"); save.addActionListener(this); shape.add(elipse); shape.add(rectangle); shape.add(roundrect); shape.add(polygon); shape.add(line); shape.add(text); shape.add(fill); shape.add(erase); shape.add(save); return shape; } public JPanel colourButtons() { JPanel colourbox=new JPanel(); colourbox.setBackground(new Color(181, 197, 210)); colourbox.setLayout(new GridLayout(8,2,8,8)); colourbox.setBounds(0,323,70,140); //colourbox.add(empty); for(int i=0;i<16;i++) { colourbutton[i]=new JButton(); colourbox.add(colourbutton[i]); if(i==0) colourbutton[0].setBackground(Color.black); else if(i==1) colourbutton[1].setBackground(Color.white); else if(i==2) colourbutton[2].setBackground(Color.red); else if(i==3) colourbutton[3].setBackground(Color.orange); else if(i==4) colourbutton[4].setBackground(Color.blue); else if(i==5) colourbutton[5].setBackground(Color.green); else if(i==6) colourbutton[6].setBackground(Color.pink); else if(i==7) colourbutton[7].setBackground(Color.magenta); else if(i==8) colourbutton[8].setBackground(Color.cyan); else if(i==9) colourbutton[9].setBackground(Color.black); else if(i==10) colourbutton[10].setBackground(Color.yellow); else if(i==11) colourbutton[11].setBackground(new Color(131,168,43)); else if(i==12) colourbutton[12].setBackground(new Color(132,0,210)); else if(i==13) colourbutton[13].setBackground(new Color(193,17,92)); else if(i==14) colourbutton[14].setBackground(new Color(129,82,50)); else if(i==15) colourbutton[15].setBackground(new Color(64,128,128)); colourbutton[i].addActionListener(this); } return colourbox; } public void fill() { if(selected=="fill") { Graphics2D g2 = (Graphics2D) image.getGraphics(); g2.setPaint(color); System.out.println("Fill"); if(fillshape=="elipse") g2.fillOval(fillstart.x, fillstart.y, (fillend.x-fillstart.x),(fillend.y-fillstart.y)); else if(fillshape=="rect") g2.fillRect(fillstart.x, fillstart.y, (fillend.x-fillstart.x),(fillend.y-fillstart.y)); else if(fillshape==("rrect")) g2.fillRoundRect(fillstart.x, fillstart.y, (fillend.x-fillstart.x),(fillend.y-fillstart.y),11,11); // else if(fillshape==("poly")) // g2.drawPolygon(x,y,2); } repaint(); } //To save the image drawn public void save() { try { ByteArrayOutputStream bos = new ByteArrayOutputStream(); JPEGImageEncoder encoder = JPEGCodec.createJPEGEncoder(bos); JFileChooser fc = new JFileChooser(); fc.showSaveDialog(this); encoder.encode(image); byte[] jpgData = bos.toByteArray(); FileOutputStream fos = new FileOutputStream(fc.getSelectedFile()+".jpeg"); fos.write(jpgData); fos.close(); //add replce confirmation here } catch (IOException e) { System.out.println(e); } } public void mouseClicked(MouseEvent e) { } @Override public void mouseEntered(MouseEvent e) { } public void mouseExited(MouseEvent arg0) { } public void mousePressed(MouseEvent e) { if(selected=="line"||selected=="text") { start=e.getPoint(); client.broadcast(start,"start", selected,"press", selectedcolor); } else if(selected=="elipse"||selected=="rect"||selected=="rrect") mp = e.getPoint(); else if(selected=="poly") { if(first==true) { start=e.getPoint(); //client.broadcast(start,"start", selected,"press", selectedcolor); } else if(first==false) { end=e.getPoint(); repaint(); //client.broadcast(end,"end", selected,"press", selectedcolor); } } else if(selected=="erase") { start=e.getPoint(); erase(); } } public void mouseReleased(MouseEvent e) { if(selected=="text") { System.out.println("Reset"); key=""; post=0; label=new Point(); label=e.getPoint(); grabFocus(); } if(start!=null && end!=null) { if(selected=="line") { end=e.getPoint(); client.broadcast(end,"end", selected,"release", selectedcolor); draw(); } else if(selected=="elipse"||selected=="rect"||selected=="rrect") { end.x = Math.max(mp.x,e.getX()); end.y = Math.max(mp.y,e.getY()); client.broadcast(end,"end", selected,"release", selectedcolor); draw(); } else if(selected=="poly") { draw(); first=false; start=end; end=null; } } } public void mouseDragged(MouseEvent e) { if(end==null) end = new Point(); if(start==null) start = new Point(); if(selected=="line") { end=e.getPoint(); client.broadcast(end,"end", selected,"drag", selectedcolor); } else if(selected=="erase") { start=e.getPoint(); erase(); client.broadcast(start,"start", selected,"drag", selectedcolor); } else if(selected=="elipse"||selected=="rect"||selected=="rrect") { start.x = Math.min(mp.x,e.getX()); start.y = Math.min(mp.y,e.getY()); end.x = Math.max(mp.x,e.getX()); end.y = Math.max(mp.y,e.getY()); client.broadcast(start,"start", selected,"drag", selectedcolor); client.broadcast(end,"end", selected,"drag", selectedcolor); } else if(selected=="poly") end=e.getPoint(); System.out.println(tooltip); if(tooltip==true) { if(selected=="erase") { Graphics2D g2=(Graphics2D) getGraphics(); tip=e.getPoint(); g2.drawRect(tip.x-10,tip.y-10,10,10); } } repaint(); } public void mouseMoved(MouseEvent e) { if(selected=="text" ||selected=="erase") { tip=new Point(); tip=e.getPoint(); tooltip=true; repaint(); } } public void actionPerformed(ActionEvent e) { if(e.getSource()==elipse) selected="elipse"; else if(e.getSource()==line) selected="line"; else if(e.getSource()==rectangle) selected="rect"; else if(e.getSource()==erase) { selected="erase"; tooltip=true; System.out.println(selected); erase(); } else if(e.getSource()==roundrect) selected="rrect"; else if(e.getSource()==polygon) { selected="poly"; first=true; start=null; } else if(e.getSource()==text) { selected="text"; tooltip=true; } else if(e.getSource()==fill) { selected="fill"; fill(); } else if(e.getSource()==save) save(); if(e.getSource()==colourbutton[0]) { color=Color.black; selectedcolor="black"; } else if(e.getSource()==colourbutton[1]) { color=Color.white; selectedcolor="white"; } else if(e.getSource()==colourbutton[2]) { color=Color.red; selectedcolor="red"; } else if(e.getSource()==colourbutton[3]) { color=Color.orange; selectedcolor="orange"; } else if(e.getSource()==colourbutton[4]) { selectedcolor="blue"; color=Color.blue; } else if(e.getSource()==colourbutton[5]) { selectedcolor="green"; color=Color.green; } else if(e.getSource()==colourbutton[6]) { selectedcolor="pink"; color=Color.pink; } else if(e.getSource()==colourbutton[7]) { selectedcolor="magenta"; color=Color.magenta; } else if(e.getSource()==colourbutton[8]) { selectedcolor="cyan"; color=Color.cyan; } } @Override public void keyPressed(KeyEvent e) { //System.out.println(e.getKeyChar()+" : "+e.getKeyCode()); if(label!=null) { if(e.getKeyCode()==10) //Check for Enter key { label.y=label.y+14; key=""; post=0; repaint(); } else if(e.getKeyCode()==8) //Backspace { try{ Graphics2D g2 = (Graphics2D) image.getGraphics(); g2.setPaint(new Color(237,237,237)); g2.fillRect(label.x+post-7, label.y-13, 14, 17); if(post>0) post=post-6; keycode=0; key=key.substring(0, key.length()-1); System.out.println(key.substring(0, key.length())); repaint(); Point broadcastlabel=new Point(); broadcastlabel.x=label.x+post-7; broadcastlabel.y=label.y-13; client.broadcast(broadcastlabel, key, "text", "backspace", selectedcolor); } catch(Exception ex) {} } //Block invalid keys else if(!(e.getKeyCode()>=16 && e.getKeyCode()<=20 || e.getKeyCode()>=112 && e.getKeyCode()<=123 || e.getKeyCode()>=33 && e.getKeyCode()<=40 || e.getKeyCode()>=144 && e.getKeyCode()<=145 || e.getKeyCode()>=524 && e.getKeyCode()<=525 ||e.getKeyCode()==27||e.getKeyCode()==155 ||e.getKeyCode()==127)) { key=key+e.getKeyChar(); post=post+6; draw(); } } } @Override public void keyReleased(KeyEvent e) { } @Override public void keyTyped(KeyEvent e) { } } class Button extends JButton { String name; int i; public Button(String name) { this.name=name; try { UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel"); } catch (Exception e) { e.printStackTrace(); } } public Button(int i) { this.i=i; } public void paintComponent(Graphics g) { super.paintComponent(g); Graphics2D g2 = (Graphics2D)g; g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); //g2.setStroke(new BasicStroke(1.2f)); if (name == "line") g.drawLine(5,5,30,30); if (name == "elipse") g.drawOval(5,7,25,20); if (name== "rect") g.drawRect(5,5,25,23); if (name== "roundrect") g.drawRoundRect(5,5,25,23,10,10); int a[]=new int[]{20,9,20,23,20}; int b[]=new int[]{9,23,25,20,9}; if (name== "poly") g.drawPolyline(a, b, 5); if (name== "text") g.drawString("Text",8, 24); } }

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  • Processing incorrect mac addresses from 802.11 frames with pcap

    - by Quentin Swain
    I'm working throurgh a project with pcap and wireless. Following an example posted in response to oe of my earlier questions I am trying to extract the mac addresses from wireless frames. I have created structures for the radiotap header and a basic management frame. For some reason when it comes to trying to output the mac addresses I am printing out the wrong data. When I compare to wireshark I don't see why the radio tap data is printing out correctly but the mac addresses are not. I don't see any additional padding in the hex dump that wireshark displays when i look at the packets and compare the packets that I have captured. I am somewhat famialar with c but not an expert so maybe I am not using the pointers and structures properly could someone help show me what I am doing wrong? Thanks, Quentin // main.c // MacSniffer // #include <pcap.h> #include <string.h> #include <stdlib.h> #define MAXBYTES2CAPTURE 65535 #ifdef WORDS_BIGENDIAN typedef struct frame_control { unsigned int subtype:4; /*frame subtype field*/ unsigned int protoVer:2; /*frame type field*/ unsigned int version:2; /*protocol version*/ unsigned int order:1; unsigned int protected:1; unsigned int moreDate:1; unsigned int power_management:1; unsigned int retry:1; unsigned int moreFrag:1; unsigned int fromDS:1; unsigned int toDS:1; }frame_control; struct ieee80211_radiotap_header{ u_int8_t it_version; u_int8_t it_pad; u_int16_t it_len; u_int32_t it_present; u_int64_t MAC_timestamp; u_int8_t flags; u_int8_t dataRate; u_int16_t channelfrequency; u_int16_t channFreq_pad; u_int16_t channelType; u_int16_t channType_pad; u_int8_t ssiSignal; u_int8_t ssiNoise; u_int8_t antenna; }; #else typedef struct frame_control { unsigned int protoVer:2; /* protocol version*/ unsigned int type:2; /*frame type field (Management,Control,Data)*/ unsigned int subtype:4; /* frame subtype*/ unsigned int toDS:1; /* frame coming from Distribution system */ unsigned int fromDS:1; /*frame coming from Distribution system */ unsigned int moreFrag:1; /* More fragments?*/ unsigned int retry:1; /*was this frame retransmitted*/ unsigned int powMgt:1; /*Power Management*/ unsigned int moreDate:1; /*More Date*/ unsigned int protectedData:1; /*Protected Data*/ unsigned int order:1; /*Order*/ }frame_control; struct ieee80211_radiotap_header{ u_int8_t it_version; u_int8_t it_pad; u_int16_t it_len; u_int32_t it_present; u_int64_t MAC_timestamp; u_int8_t flags; u_int8_t dataRate; u_int16_t channelfrequency; u_int16_t channelType; int ssiSignal:8; int ssiNoise:8; }; #endif struct wi_frame { u_int16_t fc; u_int16_t wi_duration; u_int8_t wi_add1[6]; u_int8_t wi_add2[6]; u_int8_t wi_add3[6]; u_int16_t wi_sequenceControl; // u_int8_t wi_add4[6]; //unsigned int qosControl:2; //unsigned int frameBody[23124]; }; void processPacket(u_char *arg, const struct pcap_pkthdr* pkthdr, const u_char* packet) { int i= 0, *counter = (int *) arg; struct ieee80211_radiotap_header *rh =(struct ieee80211_radiotap_header *)packet; struct wi_frame *fr= (struct wi_frame *)(packet + rh->it_len); u_char *ptr; //printf("Frame Type: %d",fr->wi_fC->type); printf("Packet count: %d\n", ++(*counter)); printf("Received Packet Size: %d\n", pkthdr->len); if(rh->it_version != NULL) { printf("Radiotap Version: %d\n",rh->it_version); } if(rh->it_pad!=NULL) { printf("Radiotap Pad: %d\n",rh->it_pad); } if(rh->it_len != NULL) { printf("Radiotap Length: %d\n",rh->it_len); } if(rh->it_present != NULL) { printf("Radiotap Present: %c\n",rh->it_present); } if(rh->MAC_timestamp != NULL) { printf("Radiotap Timestamp: %u\n",rh->MAC_timestamp); } if(rh->dataRate != NULL) { printf("Radiotap Data Rate: %u\n",rh->dataRate); } if(rh->channelfrequency != NULL) { printf("Radiotap Channel Freq: %u\n",rh->channelfrequency); } if(rh->channelType != NULL) { printf("Radiotap Channel Type: %06x\n",rh->channelType); } if(rh->ssiSignal != NULL) { printf("Radiotap SSI signal: %d\n",rh->ssiSignal); } if(rh->ssiNoise != NULL) { printf("Radiotap SSI Noise: %d\n",rh->ssiNoise); } ptr = fr->wi_add1; int k= 6; printf("Destination Address:"); do{ printf("%s%X",(k==6)?" ":":",*ptr++); } while(--k>0); printf("\n"); ptr = fr->wi_add2; k=0; printf("Source Address:"); do{ printf("%s%X",(k==6)?" ":":",*ptr++); }while(--k>0); printf("\n"); ptr = fr->wi_add3; k=0; do{ printf("%s%X",(k==6)?" ":":",*ptr++); } while(--k>0); printf("\n"); /* for(int j = 0; j < 23124;j++) { if(fr->frameBody[j]!= NULL) { printf("%x",fr->frameBody[j]); } } */ for (i = 0;i<pkthdr->len;i++) { if(isprint(packet[i +rh->it_len])) { printf("%c",packet[i + rh->it_len]); } else{printf(".");} //print newline after each section of the packet if((i%16 ==0 && i!=0) ||(i==pkthdr->len-1)) { printf("\n"); } } return; } int main(int argc, char** argv) { int count = 0; pcap_t* descr = NULL; char errbuf[PCAP_ERRBUF_SIZE], *device = NULL; struct bpf_program fp; char filter[]="wlan broadcast"; const u_char* packet; memset(errbuf,0,PCAP_ERRBUF_SIZE); device = argv[1]; if(device == NULL) { fprintf(stdout,"Supply a device name "); } descr = pcap_create(device,errbuf); pcap_set_rfmon(descr,1); pcap_set_promisc(descr,1); pcap_set_snaplen(descr,30); pcap_set_timeout(descr,10000); pcap_activate(descr); int dl =pcap_datalink(descr); printf("The Data Link type is %s",pcap_datalink_val_to_name(dl)); //pcap_dispatch(descr,MAXBYTES2CAPTURE,1,512,errbuf); //Open device in promiscuous mode //descr = pcap_open_live(device,MAXBYTES2CAPTURE,1,512,errbuf); /* if(pcap_compile(descr,&fp,filter,0,PCAP_NETMASK_UNKNOWN)==-1) { fprintf(stderr,"Error compiling filter\n"); exit(1); } if(pcap_setfilter(descr,&fp)==-1) { fprintf(stderr,"Error setting filter\n"); exit(1); } */ pcap_loop(descr,0, processPacket, (u_char *) &count); return 0; }

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  • SIGSEGV problem

    - by sickmate
    I'm designing a protocol (in C) to implement the layered OSI network structure, using cnet (http://www.csse.uwa.edu.au/cnet/). I'm getting a SIGSEGV error at runtime, however cnet compiles my source code files itself (I can't compile it through gcc) so I can't easily use any debugging tools such as gdb to find the error. Here's the structures used, and the code in question: typedef struct { char *data; } DATA; typedef struct { CnetAddr src_addr; CnetAddr dest_addr; PACKET_TYPE type; DATA data; } Packet; typedef struct { int length; int checksum; Packet datagram; } Frame; static void keyboard(CnetEvent ev, CnetTimerID timer, CnetData data) { char line[80]; int length; length = sizeof(line); CHECK(CNET_read_keyboard((void *)line, (unsigned int *)&length)); // Reads input from keyboard if(length > 1) { /* not just a blank line */ printf("\tsending %d bytes - \"%s\"\n", length, line); application_downto_transport(1, line, &length); } } void application_downto_transport(int link, char *msg, int *length) { transport_downto_network(link, msg, length); } void transport_downto_network(int link, char *msg, int *length) { Packet *p; DATA *d; p = (Packet *)malloc(sizeof(Packet)); d = (DATA *)malloc(sizeof(DATA)); d->data = msg; p->data = *d; network_downto_datalink(link, (void *)p, length); } void network_downto_datalink(int link, Packet *p, int *length) { Frame *f; // Encapsulate datagram and checksum into a Frame. f = (Frame *)malloc(sizeof(Frame)); f->checksum = CNET_crc32((unsigned char *)(p->data).data, *length); // Generate 32-bit CRC for the data. f->datagram = *p; f->length = sizeof(f); //Pass Frame to the CNET physical layer to send Frame to the require link. CHECK(CNET_write_physical(link, (void *)f, (size_t *)f->length)); free(p->data); free(p); free(f); } I managed to find that the line: CHECK(CNET_write_physical(link, (void *)f, (size_t *)f-length)); is causing the segfault but I can't work out why. Any help is greatly appreciated.

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  • DSA signature verification input

    - by calccrypto
    What is the data inputted into DSA when PGP signs a message? From RFC4880, i found A Signature packet describes a binding between some public key and some data. The most common signatures are a signature of a file or a block of text, and a signature that is a certification of a User ID. im not sure if it is the entire public key, just the public key packet, or some other derivative of a pgp key packet. whatever it is, i cannot get the DSA signature to verify here is a sample im testing my program on: -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 abcd -----BEGIN PGP SIGNATURE----- Version: BCPG v1.39 iFkEARECABkFAk0z65ESHGFiYyAodGVzdCBrZXkpIDw+AAoJEC3Jkh8+bnkusO0A oKG+HPF2Qrsth2zS9pK+eSCBSypOAKDBgC2Z0vf2EgLiiNMk8Bxpq68NkQ== =gq0e -----END PGP SIGNATURE----- Dumped from pgpdump.net Old: Signature Packet(tag 2)(89 bytes) Ver 4 - new Sig type - Signature of a canonical text document(0x01). Pub alg - DSA Digital Signature Algorithm(pub 17) Hash alg - SHA1(hash 2) Hashed Sub: signature creation time(sub 2)(4 bytes) Time - Mon Jan 17 07:11:13 UTC 2011 Hashed Sub: signer's User ID(sub 28)(17 bytes) User ID - abc (test key) <> Sub: issuer key ID(sub 16)(8 bytes) Key ID - 0x2DC9921F3E6E792E Hash left 2 bytes - b0 ed DSA r(160 bits) - a1 be 1c f1 76 42 bb 2d 87 6c d2 f6 92 be 79 20 81 4b 2a 4e DSA s(160 bits) - c1 80 2d 99 d2 f7 f6 12 02 e2 88 d3 24 f0 1c 69 ab af 0d 91 -> hash(DSA q bits) and the public key for it is: -----BEGIN PGP PUBLIC KEY BLOCK----- Version: BCPG v1.39 mOIETTPqeBECALx+i9PIc4MB2DYXeqsWUav2cUtMU1N0inmFHSF/2x0d9IWEpVzE kRc30PvmEHI1faQit7NepnHkkphrXLAoZukAoNP3PB8NRQ6lRF6/6e8siUgJtmPL Af9IZOv4PI51gg6ICLKzNO9i3bcUx4yeG2vjMOUAvsLkhSTWob0RxWppo6Pn6MOg dMQHIM5sDH0xGN0dOezzt/imAf9St2B0HQXVfAAbveXBeRoO7jj/qcGx6hWmsKUr BVzdQhBk7Sku6C2KlMtkbtzd1fj8DtnrT8XOPKGp7/Y7ASzRtBFhYmMgKHRlc3Qg a2V5KSA8PohGBBMRAgAGBQJNM+p5AAoJEC3Jkh8+bnkuNEoAnj2QnqGtdlTgUXCQ Fyvwk5wiLGPfAJ4jTGTL62nWzsgrCDIMIfEG2shm8bjMBE0z6ngQAgCUlP7AlfO4 XuKGVCs4NvyBpd0KA0m0wjndOHRNSIz44x24vLfTO0GrueWjPMqRRLHO8zLJS/BX O/BHo6ypjN87Af0VPV1hcq20MEW2iujh3hBwthNwBWhtKdPXOndJGZaB7lshLJuW v9z6WyDNXj/SBEiV1gnPm0ELeg8Syhy5pCjMAgCFEc+NkCzcUOJkVpgLpk+VLwrJ /Wi9q+yCihaJ4EEFt/7vzqmrooXWz2vMugD1C+llN6HkCHTnuMH07/E/2dzciEYE GBECAAYFAk0z6nkACgkQLcmSHz5ueS7NTwCdED1P9NhgR2LqwyS+AEyqlQ0d5joA oK9xPUzjg4FlB+1QTHoOhuokxxyN =CTgL -----END PGP PUBLIC KEY BLOCK----- the public key packet of the key is mOIETTPqeBECALx+i9PIc4MB2DYXeqsWUav2cUtMU1N0inmFHSF/2x0d9IWEpVzEkRc30PvmEHI1faQi t7NepnHkkphrXLAoZukAoNP3PB8NRQ6lRF6/6e8siUgJtmPLAf9IZOv4PI51gg6ICLKzNO9i3bcUx4ye G2vjMOUAvsLkhSTWob0RxWppo6Pn6MOgdMQHIM5sDH0xGN0dOezzt/imAf9St2B0HQXVfAAbveXBeRoO 7jj/qcGx6hWmsKUrBVzdQhBk7Sku6C2KlMtkbtzd1fj8DtnrT8XOPKGp7/Y7ASzR in radix 64 i have tried many different combinations of sha1(< some data + 'abcd'),but the calculated value v never equals r, of the signature i know that the pgp implementation i used to create the key and signature is correct. i also know that my DSA implementation and PGP key data extraction program are correct. thus, the only thing left is the data to hash. what is the correct data to be hashed?

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  • paket drop and splits in udp tunnel

    - by sr-dusad
    hi guys ! Currently I am working on video conferencing project.For this i m using pwnat for nat traversing. pwnat is based on udp tunneling.I m using the TCP connection for data transmission. My problem is that when i send a packet , it does not reach properly at its destination side . Sometime it drops the packet and many times it breaks ( split ) the packet into pieces. Please Help me .. How can i send and recieve a packet into single piece. So, i can draw image properly and play sound. Any kind of help will be appriciated . Thanks in advance

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  • TCP sequence number question

    - by Meta
    This is more of a theoretical question than an actual problem I have. If I understand correctly, the sequence number in the TCP header of a packet is the index of the first byte in the packet in the whole stream, correct? If that is the case, since the sequence number is an unsigned 32-bit integer, then what happens after more than FFFFFFFF = 4294967295 bytes are transferred? Will the sequence number wrap around, or will the sender send a SYN packet to restart at 0?

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  • protocol parsing in c

    - by nomad.alien
    I have been playing around with trying to implement some protocol decoders, but each time I run into a "simple" problem and I feel the way I am solving the problem is not optimal and there must be a better way to do things. I'm using C. Currently I'm using some canned data and reading it in as a file, but later on it would be via TCP or UDP. Here's the problem. I'm currently playing with a binary protocol at work. All fields are 8 bits long. The first field(8bits) is the packet type. So I read in the first 8 bits and using a switch/case I call a function to read in the rest of the packet as I then know the size/structure of it. BUT...some of these packets have nested packets inside them, so when I encounter that specific packet I then have to read another 8-16 bytes have another switch/case to see what the next packet type is and on and on. (Luckily the packets are only nested 2 or 3 deep). Only once I have the whole packet decoded can I handle it over to my state machine for processing. I guess this can be a more general question as well. How much data do you have to read at a time from the socket? As much as possible? As much as what is "similar" in the protocol headers? So even though this protocol is fairly basic, my code is a whole bunch of switch/case statements and I do a lot of reading from the file/socket which I feel is not optimal. My main aim is to make this decoder as fast as possible. To the more experienced people out there, is this the way to go or is there a better way which I just haven't figured out yet? Any elegant solution to this problem?

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  • C++/CLI HTTP Proxy problems...

    - by darkantimatter
    Hi, I'm trying(very hard) to make a small HTTP Proxy server which I can use to save all communications to a file. Seeing as I dont really have any experience in the area, I used a class from codeproject.com and some associated code to get started (It was made in the old CLI syntax, so I converted it). I couldn't get it working, so I added lots more code to make it work (threads etc), and now it sort of works. Basically, it recieves something from a client (I just configured Mozilla Firefox to route its connections through this proxy) and then routes it to google.com. After it sends Mozilla's data to google, recieves a responce, and sends that to Mozilla. This works fine, but then the proxy fails to recieve any data from Mozilla. It just loops in the Sleep(50) section. Anyway, heres the code: ProxyTest.cpp: #include "stdafx.h" #include "windows.h" #include "CHTTPProxy.h" public ref class ClientThread { public: System::Net::Sockets::TcpClient ^ pClient; CHttpProxy ^ pProxy; System::Int32 ^ pRecieveBufferSize; System::Threading::Thread ^ Thread; ClientThread(System::Net::Sockets::TcpClient ^ sClient, CHttpProxy ^ sProxy, System::Int32 ^ sRecieveBufferSize) { pClient = sClient; pProxy = sProxy; pRecieveBufferSize = sRecieveBufferSize; }; void StartReading() { Thread = gcnew System::Threading::Thread(gcnew System::Threading::ThreadStart(this,&ClientThread::ThreadEntryPoint)); Thread->Start(); }; void ThreadEntryPoint() { char * bytess; bytess = new char[(int)pRecieveBufferSize]; memset(bytess, 0, (int)pRecieveBufferSize); array<unsigned char> ^ bytes = gcnew array<unsigned char>((int)pRecieveBufferSize); array<unsigned char> ^ sendbytes; do { if (pClient->GetStream()->DataAvailable) { try { do { Sleep(100); //Lets wait for whole packet to get cached (If it even does...) unsigned int k = pClient->GetStream()->Read(bytes, 0, (int)pRecieveBufferSize); //Read it for(unsigned int i=0; i<(int)pRecieveBufferSize; i++) bytess[i] = bytes[i]; Console::WriteLine("Packet Received:\n"+gcnew System::String(bytess)); pProxy->SendToServer(bytes,pClient->GetStream()); //Now send it to google! pClient->GetStream()->Flush(); } while(pClient->GetStream()->DataAvailable); } catch (Exception ^ e) { break; } } else { Sleep(50); //It just loops here because it thinks mozilla isnt sending anything if (!(pClient->Connected)) break; }; } while (pClient->GetStream()->CanRead); delete [] bytess; pClient->Close(); }; }; int main(array<System::String ^> ^args) { System::Collections::Generic::Stack<ClientThread ^> ^ Clients = gcnew System::Collections::Generic::Stack<ClientThread ^>(); System::Net::Sockets::TcpListener ^ pTcpListener = gcnew System::Net::Sockets::TcpListener(8080); pTcpListener->Start(); System::Net::Sockets::TcpClient ^ pTcpClient; while (1) { pTcpClient = pTcpListener->AcceptTcpClient(); //Wait for client ClientThread ^ Client = gcnew ClientThread(pTcpClient, gcnew CHttpProxy("www.google.com.au", 80), pTcpClient->ReceiveBufferSize); //Make a new object for this client Client->StartReading(); //Start the thread Clients->Push(Client); //Add it to the list }; pTcpListener->Stop(); return 0; } CHTTPProxy.h, from http://www.codeproject.com/KB/IP/howtoproxy.aspx with a lot of modifications: //THIS FILE IS FROM http://www.codeproject.com/KB/IP/howtoproxy.aspx. I DID NOT MAKE THIS! BUT I HAVE MADE SEVERAL MODIFICATIONS! #using <mscorlib.dll> #using <SYSTEM.DLL> using namespace System; using System::Net::Sockets::TcpClient; using System::String; using System::Exception; using System::Net::Sockets::NetworkStream; #include <stdio.h> ref class CHttpProxy { public: CHttpProxy(System::String ^ szHost, int port); System::String ^ m_host; int m_port; void SendToServer(array<unsigned char> ^ Packet, System::Net::Sockets::NetworkStream ^ sendstr); }; CHttpProxy::CHttpProxy(System::String ^ szHost, int port) { m_host = gcnew System::String(szHost); m_port = port; } void CHttpProxy::SendToServer(array<unsigned char> ^ Packet, System::Net::Sockets::NetworkStream ^ sendstr) { TcpClient ^ tcpclnt = gcnew TcpClient(); try { tcpclnt->Connect(m_host,m_port); } catch (Exception ^ e ) { Console::WriteLine(e->ToString()); return; } // Send it if ( tcpclnt ) { NetworkStream ^ networkStream; networkStream = tcpclnt->GetStream(); int size = Packet->Length; networkStream->Write(Packet, 0, size); array<unsigned char> ^ bytes = gcnew array<unsigned char>(tcpclnt->ReceiveBufferSize); char * bytess = new char[tcpclnt->ReceiveBufferSize]; Sleep(500); //Wait for responce do { unsigned int k = networkStream->Read(bytes, 0, (int)tcpclnt->ReceiveBufferSize); //Read from google for(unsigned int i=0; i<k; i++) { bytess[i] = bytes[i]; if (bytess[i] == 0) bytess[i] = ' '; //Dont terminate the string if (bytess[i] < 8) bytess[i] = ' '; //Somethings making the computer beep, and its not 7?!?! }; Console::WriteLine("\n\nAbove packet sent to google. Google Packet Received:\n"+gcnew System::String(bytess)); sendstr->Write(bytes,0,k); //Send it to mozilla Console::WriteLine("\n\nAbove packet sent to client..."); //Sleep(1000); } while(networkStream->DataAvailable); delete [] bytess; } return; } Any help would be much appreciated, I've tried for hours.

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  • How to Broadcast to a shutdown system using java?

    - by pirates-iiita
    We use socket.send(packet) function in java to send a "packet" to a given port. My problem is that i have to send a packet to a shutdown system using UDP protocol. The problem with send() function is that first it verifies whether the host IP is multicast or not. Now my local area network is of broadcast type. So i am having problem is using this function. can anyone please give me a way ?

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  • Router Alert options on IGMPv2 packets

    - by Scakko
    I'm trying to forge an IGMPv2 Membership Request packet and send it on a RAW socket. The RFC 3376 states: IGMP messages are encapsulated in IPv4 datagrams, with an IP protocol number of 2. Every IGMP message described in this document is sent with an IP Time-to-Live of 1, IP Precedence of Internetwork Control (e.g., Type of Service 0xc0), and carries an IP Router Alert option [RFC-2113] in its IP header So the IP_ROUTER_ALERT flag must be set. I'm trying to forge the strict necessary of the packet (e.g. only the IGMP header & payload), so i'm using the setsockopt to edit the IP options. some useful variables: #define C_IP_MULTICAST_TTL 1 #define C_IP_ROUTER_ALERT 1 int sockfd = 0; int ecsockopt = 0; int bytes_num = 0; int ip_multicast_ttl = C_IP_MULTICAST_TTL; int ip_router_alert = C_IP_ROUTER_ALERT; Here's how I open the RAW socket: sock_domain = AF_INET; sock_type = SOCK_RAW; sock_proto = IPPROTO_IGMP; if ((ecsockopt = socket(sock_domain,sock_type,sock_proto)) < 0) { printf("Error %d: Can't open socket.\n", errno); return 1; } else { printf("** Socket opened.\n"); } sockfd = ecsockopt; Then I set the TTL and Router Alert option: // Set the sent packets TTL if((ecsockopt = setsockopt(sockfd, IPPROTO_IP, IP_MULTICAST_TTL, &ip_multicast_ttl, sizeof(ip_multicast_ttl))) < 0) { printf("Error %d: Can't set TTL.\n", ecsockopt); return 1; } else { printf("** TTL set.\n"); } // Set the Router Alert if((ecsockopt = setsockopt(sockfd, IPPROTO_IP, IP_ROUTER_ALERT, &ip_router_alert, sizeof(ip_router_alert))) < 0) { printf("Error %d: Can't set Router Alert.\n", ecsockopt); return 1; } else { printf("** Router Alert set.\n"); } The setsockopt of IP_ROUTER_ALERT returns 0. After forging the packet, i send it with sendto in this way: // Send the packet if((bytes_num = sendto(sockfd, packet, packet_size, 0, (struct sockaddr*) &mgroup1_addr, sizeof(mgroup1_addr))) < 0) { printf("Error %d: Can't send Membership report message.\n", bytes_num); return 1; } else { printf("** Membership report message sent. (bytes=%d)\n",bytes_num); } The packet is sent, but the IP_ROUTER_ALERT option (checked with wireshark) is missing. Am i doing something wrong? is there some other methods to set the IP_ROUTER_ALERT option? Thanks in advance.

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  • Trying to packetize TCP with non-blocking IO is hard! Am I doing something wrong?

    - by Ricket
    Oh how I wish TCP was packet-based like UDP is! But alas, that's not the case, so I'm trying to implement my own packet layer. Here's the chain of events so far (ignoring writing packets) Oh, and my Packets are very simply structured: two unsigned bytes for length, and then byte[length] data. (I can't imagine if they were any more complex, I'd be up to my ears in if statements!) Server is in an infinite loop, accepting connections and adding them to a list of Connections. PacketGatherer (another thread) uses a Selector to figure out which Connection.SocketChannels are ready for reading. It loops over the results and tells each Connection to read(). Each Connection has a partial IncomingPacket and a list of Packets which have been fully read and are waiting to be processed. On read(): Tell the partial IncomingPacket to read more data. (IncomingPacket.readData below) If it's done reading (IncomingPacket.complete()), make a Packet from it and stick the Packet into the list waiting to be processed and then replace it with a new IncomingPacket. There are a couple problems with this. First, only one packet is being read at a time. If the IncomingPacket needs only one more byte, then only one byte is read this pass. This can of course be fixed with a loop but it starts to get sorta complicated and I wonder if there is a better overall way. Second, the logic in IncomingPacket is a little bit crazy, to be able to read the two bytes for the length and then read the actual data. Here is the code, boiled down for quick & easy reading: int readBytes; // number of total bytes read so far byte length1, length2; // each byte in an unsigned short int (see getLength()) public int getLength() { // will be inaccurate if readBytes < 2 return (int)(length1 << 8 | length2); } public void readData(SocketChannel c) { if (readBytes < 2) { // we don't yet know the length of the actual data ByteBuffer lengthBuffer = ByteBuffer.allocate(2 - readBytes); numBytesRead = c.read(lengthBuffer); if(readBytes == 0) { if(numBytesRead >= 1) length1 = lengthBuffer.get(); if(numBytesRead == 2) length2 = lengthBuffer.get(); } else if(readBytes == 1) { if(numBytesRead == 1) length2 = lengthBuffer.get(); } readBytes += numBytesRead; } if(readBytes >= 2) { // then we know we have the entire length variable // lazily-instantiate data buffers based on getLength() // read into data buffers, increment readBytes // (does not read more than the amount of this packet, so it does not // need to handle overflow into the next packet's data) } } public boolean complete() { return (readBytes > 2 && readBytes == getLength()+2); } Basically I need feedback on my code. Please suggest any improvements. Even overhauling my entire system would be okay, if you have suggestions for how better to implement the whole thing. Book recommendations are welcome too; I love books. I just get the feeling that something isn't quite right.

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  • probelm with recv() on a tcp connection

    - by michael
    Hi, I am simulating TCP communication on windows in C I have sender and a receiver communicating. sender sends packets of specific size to receiver. receiver gets them and send an ACK for each packet it received back to the sender. If the sender didn't get a specific packet (they are numbered in a header inside the packet) it sends the packet again to the receiver. Here is the getPacket function on the receiver side: //get the next packet from the socket. set the packetSize to -1 //if it's the first packet. //return: total bytes read // return: 0 if socket has shutdown on sender side, -1 error, else number of bytes received int getPakcet(char *chunkBuff,int packetSize,SOCKET AcceptSocket){ int totalChunkLen = 0; int bytesRecv=-1; bool firstTime=false; if (packetSize==-1) { packetSize=MAX_PACKET_LENGTH; firstTime=true; } int needToGet=packetSize; do { char* recvBuff; recvBuff = (char*)calloc(needToGet,sizeof(char)); if(recvBuff == NULL){ fprintf(stderr,"Memory allocation problem\n"); return -1; } bytesRecv = recv(AcceptSocket, recvBuff, needToGet, 0); if (bytesRecv == SOCKET_ERROR){ fprintf(stderr,"recv() error %ld.\n", WSAGetLastError()); totalChunkLen=-1; return -1; } if (bytesRecv == 0){ fprintf(stderr,"recv(): socket has shutdown on sender side"); return 0; } else if(bytesRecv > 0) { memcpy(chunkBuff + totalChunkLen,recvBuff,bytesRecv); totalChunkLen+=bytesRecv; } needToGet-=bytesRecv; } while ((totalChunkLen < packetSize) && (!firstTime)); return totalChunkLen; } i use firstTime because for the first time the receiver doesn't know the normal package size that the sender is going to send to it, so i use a MAX_PACKET_LENGTH to get a package and then set the normal package size to the num of bytes i have received my problem is the last package. it's size is less than the package size so lets say last package size is 2 and the normal package size is 4. so recv() gets two bytes, continues to the while condition, then totalChunkLen < packetSize because 2<4 so it iterates the loop again and the gets stuck in recv() because it's blocking because the sender has nothing to send. on the sender side i can't close the connection because i didn't ACK back, so it's kind of a deadlock. receiver is stuck because it's waiting for more packages but sender has nothing to send. i don't want to use a timeout for recv() or to insert a special character to the package header to mark that it is the last one what can i do ? thanks

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  • reading partially from sockets

    - by nomad.alien
    I'm having a little test program that sends a lot of udp packets between client-server-client (ping/pong test). The packets are fixed size on each run(last run is max allowable size of udp packet) I'm filling the packets with random data except for the beginning of each packet that contains the packet number. So I'm only interested to see if I receive all the packets back at the client. I'm using sendto() and recvfrom() and I only read the sizeof(packet_number) (which in this case is an int). What happens to the rest of the data? Does it end up in fairyland (gets discarded)? or does the new packet that arrives gets appended to this "old" data? (using linux)

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  • How an application or website finds your ip?

    - by johnkills
    I think there are only two ways a application or a server could get your IP. If it is an application, java/flash, I think it could check your network settings locally and send your IP back to the server. Then the server would know. The other way it could find is that it could analyze the packet headers. Then find there your IP information. But if I wanted it to stop doing it. If it was analyzing locally my IP information I could stop that packet or change its information so the website would be confused about the IP information. If it was analyzing the packet headers and if knew what packets it was analyzing because it wont analyze every packet, I could stop sending those packets. Example: Websites that checks your IP, how does it do it? If you are not downloading any application, you would exclude the 1. scenarion. Then the only possibility is that it was analyzing packet headers but what kind of packets? It was not one question only but if anyone knows something about it, I would like to know too. :) Thanks

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  • Creating a new variable in C from only part of an existing u_char

    - by Alex Kloss
    I'm writing some C code to parse IEEE 802.11 frames, but I'm stuck trying to create a new variable whose length depends on the size of the frame itself. Here's the code I currently have: int frame_body_len = pkt_hdr->len - radio_hdr->len - wifi_hdr_len - 4; u_char *frame_body = (u_char *) (packet + radio_hdr->len + wifi_hdr_len); Basically, the frame consists of a header, a body, and a checksum at the end. I can calculate the length of the frame body by taking the length of the packet and subtracting the length of the two headers that appear before it (radio_hdr->len and wifi_hdr_len respectively), plus 4 bytes at the end for the checksum. However, how can I create the frame_body variable without the trailing checksum? Right now, I'm initializing it with the contents of the packet starting at the position after the two headers, but is there some way to start at that position and end 4 bytes before the end of packet? packet is a pointer to a u_char, if it helps. I'm a new C programmer, so any and all advice about my code you can give me would be much appreciated. Thanks!

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  • safe structures embedded systems

    - by user405633
    I have a packet from a server which is parsed in an embedded system. I need to parse it in a very efficient way, avoiding memory issues, like overlapping, corrupting my memory and others variables. The packet has this structure "String A:String B:String C". As example, here the packet received is compounded of three parts separated using a separator ":", all these parts must be accesibles from an structure. Which is the most efficient and safe way to do this. A.- Creating an structure with attributes (partA, PartB PartC) sized with a criteria based on avoid exceed this sized from the source of the packet, and attaching also an index with the length of each part in a way to avoid extracting garbage, this part length indicator could be less or equal to 300 (ie: part B). typedef struct parsedPacket_struct { char partA[2];int len_partA; char partB[300];int len_partB; char partC[2];int len_partC; }parsedPacket; The problem here is that I am wasting memory, because each structure should copy the packet content to each the structure, is there a way to only save the base address of each part and still using the len_partX.

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  • Timer C#. Start, stop, and get the amount of time between the calls

    - by user1886060
    I'm writing UDP chat with reliable data transfer. I need to start a timer when a packet is sent, and stop it as soon it receives an answer from the server(ACK- acknowledgment). Here is my code: private void sendButton_Click(object sender, EventArgs e) { Packet snd = new Packet(ack, textBox1.Text.Trim()); textBox1.Text = string.Empty; Smsg = snd.GetDataStream();//convert message into array of bytes to send. while (true) { try { // Here I need to Start a timer! clientSock.SendTo(Smsg, servEP); clientSock.ReceiveFrom(Rmsg, ref servEP); //Here I need to stop a timer and get elapsed amount of time. Packet rcv = new Packet(Rmsg); if (Rmsg != null && rcv.ACK01 != ack) continue; if (Rmsg != null && rcv.ACK01 == ack) { this.displayMessageDelegate("ack is received :"+ack); ChangeAck(ack); break; } Thank you.

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  • Make The Web Fast - The HAR Show: Capturing and Analyzing performance data with HTTP Archive format

    Make The Web Fast - The HAR Show: Capturing and Analyzing performance data with HTTP Archive format Need a flexible format to record, export, and analyze network performance data? Well, that's exactly what the HTTP Archive format (HAR) is designed to do! Even better, did you know that Chrome DevTools supports it? In this episode we'll take a deep dive into the format (as you'll see, its very simple), and explore the many different ways it can help you capture and analyze your sites performance. Join +Ilya Grigorik and +Peter Lubbers to find out how to capture HAR network traces in Chrome, visualize the data via an online tool, share the reports with your clients and coworkers, automate the logging and capture of HAR data for your build scripts, and even adapt it to server-side analysis use cases! Yes, a rapid fire session of awesome demos - see you there. From: GoogleDevelopers Views: 0 6 ratings Time: 00:00 More in Science & Technology

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  • install wireshark 1.8.3 in ubuntu 12.04

    - by gene
    To enable capture traffic on multiple interfaces at once, I tried to install wireshark 1.8.3. However, I encountered the following errors: capture-pcap-util.c:274:1: error: static declaration of ‘pcap_datalink_name_to_val’ follows non-static declaration /usr/local/include/pcap/pcap.h:326:5: note: previous declaration of ‘pcap_datalink_name_to_val’ was here capture-pcap-util.c:289:1: error: static declaration of ‘pcap_datalink_val_to_name’ follows non-static declaration /usr/local/include/pcap/pcap.h:327:13: note: previous declaration of ‘pcap_datalink_val_to_name’ was here After doing some search, I found someone can fix it by reinstall libpcap-dev, or the following commands: step 1:rm & rmdir any file in '/usr/include/pcap';'/usr/local/include/pcap' step 2:Download libpcap by 'sudo apt-get install libpcap0.8-dev' step 3:./autogen.sh in wireshark dir step 4:make clean & make & make install However, neither is working on ubuntu 12.04/wireshark 1.8.3 Anyone can help?

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