网卡抓取--1（数据包）

使用jFreeChart实现web实时设备状态的图形化监控之三：使用jPcap抓取网络数据包小试

抓包前，首先要编写实现了PacketReceiver接口的类，即数据包处理器，由与抓包时，对应某个网络接口的JpcapCaptor对象会阻塞，所以我们将每个网卡上得到的对应的JpcapCaptor对象放到一个独立线程中运行；TestPacketReceiver是个数据包解析器，本例中我们只是简单打印出收到的数据包类型及关键参数，阅读如下代码建议参照jPcap的在线文档(http://netresearch.ics.uci.edu/kfujii/jpcap/doc/javadoc/index.html )

TestPacketReceiver.java代码如下：

 

import jpcap.JpcapCaptor;
import jpcap.NetworkInterface;
import jpcap.PacketReceiver;
import jpcap.packet.*;
/**
 * 使用jpcap显示网络上的各种数据包
 * @author www.NetJava.cn
 */
public class DispalyNetPacket {

    //程序启动主方法
   public static void main(String args[]){
       try{
            //获取本机上的网络接口对象数组
     final  NetworkInterface[] devices = JpcapCaptor.getDeviceList();
        for(int i=0;i<devices.length;i++){
            NetworkInterface nc=devices[i];
           //创建某个卡口上的抓取对象,最大为2000个
        JpcapCaptor jpcap = JpcapCaptor.openDevice(nc, 2000, true, 20);
        startCapThread(jpcap);
        System.out.println("开始抓取第"+i+"个卡口上的数据");
        }
        }catch(Exception ef){
            ef.printStackTrace();
            System.out.println("启动失败:  "+ef);
        }

   }
    //将每个Captor放到独立线程中运行
   public static void startCapThread(final JpcapCaptor jpcap ){
       JpcapCaptor jp=jpcap;
       java.lang.Runnable rnner=new Runnable(){
           public void run(){
               //使用接包处理器循环抓包
               jpcap.loopPacket(-1, new TestPacketReceiver());
           }
       };
       new Thread(rnner).start();//启动抓包线程
   }
}

/**
 * 抓包监听器,实现PacketReceiver中的方法:打印出数据包说明
 * @author www.NetJava.cn
 */
class TestPacketReceiver  implements PacketReceiver {
      /**
       * 实现的接包方法:
       */
      public void receivePacket(Packet packet) {
          //Tcp包,在java Socket中只能得到负载数据
        if(packet instanceof jpcap.packet.TCPPacket){
            TCPPacket p=(TCPPacket)packet;
            String s="TCPPacket:| dst_ip "+p.dst_ip+":"+p.dst_port
                     +"|src_ip "+p.src_ip+":"+p.src_port
                     +" |len: "+p.len;
        System.out.println(s);
        }
        //UDP包,开着QQ,你就会看到:它是tcp+udp
        else if(packet instanceof jpcap.packet.UDPPacket){
            UDPPacket p=(UDPPacket)packet;
            String s="UDPPacket:| dst_ip "+p.dst_ip+":"+p.dst_port
             +"|src_ip "+p.src_ip+":"+p.src_port
            +" |len: "+p.len;
           System.out.println(s);
        }
        //如果你要在程序中构造一个ping报文,就要构建ICMPPacket包
       else if(packet instanceof jpcap.packet.ICMPPacket){
           ICMPPacket p=(ICMPPacket)packet;
           //ICMP包的路由链
           String router_ip="";
           for(int i=0;i<p.router_ip.length;i++){
               router_ip+=" "+p.router_ip[i].getHostAddress();
           }
            String s="@ @ @ ICMPPacket:| router_ip "+router_ip
             +" |redir_ip: "+p.redir_ip
             +" |mtu: "+p.mtu
             +" |length: "+p.len;
          System.out.println(s);
        }
        //是否地址转换协议请求包
       else if(packet instanceof jpcap.packet.ARPPacket){
           ARPPacket p=(ARPPacket)packet;
           //Returns the hardware address (MAC address) of the sender
           Object  saa=   p.getSenderHardwareAddress();
           Object  taa=p.getTargetHardwareAddress();
           String s="* * * ARPPacket:| SenderHardwareAddress "+saa
             +"|TargetHardwareAddress "+taa
             +" |len: "+p.len;
         System.out.println(s);

        }
    //取得链路层数据头 :如果你想局网抓包或伪造数据包，嘿嘿
     DatalinkPacket datalink  =packet.datalink;
     //如果是以太网包
     if(datalink instanceof jpcap.packet.EthernetPacket){
         EthernetPacket ep=(EthernetPacket)datalink;
          String s="  datalink layer packet: "
              +"|DestinationAddress: "+ep.getDestinationAddress()
              +"|SourceAddress: "+ep.getSourceAddress();
          System.out.println(s);
    }
  }

}

 

 

 

 运行这段程序，你机器从网络收所有收发到的数据，就都可以展现在你眼前了！，在我的机器上，摘抄一段输出如下：

datalink layer packet: |DestinationAddress: 01:00:5e:00:00:01|SourceAddress: 00:19:e0:f0:ee:55   datalink layer packet: |DestinationAddress: 01:00:5e:26:4c:da|SourceAddress: 00:e0:81:03:7c:01TCPPacket:| dst_ip /128.195.10.200:80|src_ip /192.168.1.44:1083 |len: 62  datalink layer packet: |DestinationAddress: 00:19:e0:f0:ee:55|SourceAddress: 00:02:8a:96:d1:ab* * * ARPPacket:| SenderHardwareAddress 00:19:e0:f0:ee:55|TargetHardwareAddress 00:00:00:00:00:00 |len: 60  datalink layer packet: |DestinationAddress: ff:ff:ff:ff:ff:ff|SourceAddress: 00:19:e0:f0:ee:55* * * ARPPacket:| SenderHardwareAddress 00:02:8a:96:d1:ab|TargetHardwareAddress 00:19:e0:f0:ee:55 |len: 42  datalink layer packet: |DestinationAddress: 00:19:e0:f0:ee:55|SourceAddress: 00:02:8a:96:d1:abTCPPacket:| dst_ip /192.168.1.44:1083|src_ip /128.195.10.200:80 |len: 62  datalink layer packet: |DestinationAddress: 00:02:8a:96:d1:ab|SourceAddress: 00:19:e0:f0:ee:55

注意：你可能认为要抓取的数据包应分为发送出去的和接收到的；但对jPcap而言，数据包是从网卡上抓取到的一个packet对象，packet没有收发的概念；如果你要确定这个packet的方向，则可根据其中的属性数据值，如源地址、目标地址确认。如果想深入的研究网络协议就请继续钻研吧，我们的任务可仅仅只是统计网络流量，demo了这么多，赶快实现我们的数据统计模块：