jnetpcap get html web page source code

Question

I'm using jnetpcap to analyzing packet. I want to get html web page source code.

However, when I use html.page() to get source code I get some messy code which look like binary code. Can anyone help me? How to solve it?

Answer 1

Not a jnetpcap expert, but I have been using this class for a while and it seems to work. It actually gets many HTTP fields, including its payload.

package br.com.mvalle.ids.sniffer;

import java.util.ArrayList;  
import java.util.Date;  
import java.util.List;  

import org.jnetpcap.Pcap;  
import org.jnetpcap.PcapIf;  
import org.jnetpcap.packet.PcapPacket;  
import org.jnetpcap.packet.PcapPacketHandler; 
import org.jnetpcap.packet.format.FormatUtils;
import org.jnetpcap.protocol.network.Ip4;
import org.jnetpcap.protocol.tcpip.Http;
import org.jnetpcap.protocol.tcpip.Tcp;

public class Sniffer {
private List<PcapIf> alldevs = new ArrayList<PcapIf>(); // Will be filled with NICs  
private StringBuilder errbuf = new StringBuilder(); // For any error msgs 
private PcapIf selectedDevice;
private Pcap pcap;
private PcapPacketHandler<String> jpacketHandler;

public Sniffer(){
    listDevices();
    selectedDevice = selectDevice(1);
    openDevice(selectedDevice);
    packetHandler();
    capturePackets();
}

public void listDevices(){
    int r = Pcap.findAllDevs(alldevs, errbuf);  
    if (r == Pcap.NOT_OK || alldevs.isEmpty()) {  
            System.err.printf("Can't read list of devices, error is %s", errbuf.toString());  
        return;  
    }  

    System.out.println("Network devices found:");  

    int i = 0;  
    for (PcapIf device : alldevs) {  
        String description =  
            (device.getDescription() != null) ? device.getDescription()  
                : "No description available";  
        System.out.printf("#%d: %s [%s]\n", i++, device.getName(), description);  
    }  
}


private PcapIf selectDevice(int deviceId){
    PcapIf device = alldevs.get(1); // We know we have atleast 1 device   (parameter changed from 0 to 1)
    System.out  
        .printf("\nChoosing '%s' on your behalf:\n",  
            (device.getDescription() != null) ? device.getDescription()  
                : device.getName());
    return device;
}


private void openDevice (PcapIf device){
    int snaplen = 64 * 1024;           // Capture all packets, no trucation  
    int flags = Pcap.MODE_PROMISCUOUS; // capture all packets  
    int timeout = 10 * 1000;           // 10 seconds in millis  
    pcap =  
        Pcap.openLive(device.getName(), snaplen, flags, timeout, errbuf);  

    if (pcap == null) {  
        System.err.printf("Error while opening device for capture: "  
            + errbuf.toString());  
        return;  
    }        
}


private void packetHandler(){
    jpacketHandler = new PcapPacketHandler<String>() {   
    Http httpheader = new Http();

    public void nextPacket(PcapPacket packet, String user) {  
        if(packet.hasHeader(httpheader)){
            System.out.println(httpheader.toString());
            if(httpheader.hasPayload()){
               System.out.println("HTTP payload: (string length is "
                     +new String(httpheader.getPayload()).length()+")");
               System.out.println(new String(httpheader.getPayload()));
               System.out.println("HTTP truncated? "
                     +httpheader.isPayloadTruncated());
            }
            //System.out.println(packet.toString());
        }}
    }; 
}


private void capturePackets(){
    pcap.loop(pcap.LOOP_INFINITE  , jpacketHandler, "Received Packet");  
    pcap.close();  
}
}

Hope it helps.