使用Jpcap創建反向代理

Question

我需要創建一個程序來接收HTTP請求並將這些請求轉發給Web服務器。

Diagram http://img269.imageshack.us/img269/1862/h98trsly.jpg

我已經成功地使這個只使用Java的套接字，但客戶需要JPCAP要實施的計劃。我想知道這是否可能，以及我應該爲這個項目閱讀哪些文獻。

這是我現在已經從JPCAP教程片拼接起來：

import java.net.InetAddress; 
import java.io.*; 
import jpcap.*; 
import jpcap.packet.*; 


public class Router { 
    public static void main(String args[]) { 
     //Obtain the list of network interfaces 
     NetworkInterface[] devices = JpcapCaptor.getDeviceList(); 

     //for each network interface 
     for (int i = 0; i < devices.length; i++) { 
      //print out its name and description 
      System.out.println(i+": "+devices[i].name + "(" + devices[i].description+")"); 

      //print out its datalink name and description 
      System.out.println(" datalink: "+devices[i].datalink_name + "(" + devices[i].datalink_description+")"); 

      //print out its MAC address 
      System.out.print(" MAC address:"); 
      for (byte b : devices[i].mac_address) 
       System.out.print(Integer.toHexString(b&0xff) + ":"); 
      System.out.println(); 

      //print out its IP address, subnet mask and broadcast address 
      for (NetworkInterfaceAddress a : devices[i].addresses) 
       System.out.println(" address:"+a.address + " " + a.subnet + " "+ a.broadcast); 
     } 

     int index = 1; // set index of the interface that you want to open. 

     //Open an interface with openDevice(NetworkInterface intrface, int snaplen, boolean promics, int to_ms) 
     JpcapCaptor captor = null; 
     try { 
      captor = JpcapCaptor.openDevice(devices[index], 65535, false, 20); 
      captor.setFilter("port 80 and host 192.168.56.1", true); 
     } catch(java.io.IOException e) { 
      System.err.println(e); 
     } 

     //call processPacket() to let Jpcap call PacketPrinter.receivePacket() for every packet capture. 
     captor.loopPacket(-1,new PacketPrinter()); 

     captor.close(); 
    } 
} 

class PacketPrinter implements PacketReceiver { 
    //this method is called every time Jpcap captures a packet 
    public void receivePacket(Packet p) { 
     JpcapSender sender = null; 
     try { 
      NetworkInterface[] devices = JpcapCaptor.getDeviceList(); 
      sender = JpcapSender.openDevice(devices[1]); 
     } catch(IOException e) { 
      System.err.println(e); 
     } 


     IPPacket packet = (IPPacket)p; 

     try { 
      // IP Address of machine sending HTTP requests (the client) 
      // It's still on the same LAN as the servers for testing purposes. 
      packet.dst_ip = InetAddress.getByName("192.168.56.2"); 
     } catch(java.net.UnknownHostException e) { 
      System.err.println(e); 
     } 

     //create an Ethernet packet (frame) 
     EthernetPacket ether=new EthernetPacket(); 
     //set frame type as IP 
     ether.frametype=EthernetPacket.ETHERTYPE_IP; 
     //set source and destination MAC addresses 

     // MAC Address of machine running reverse proxy server 
     ether.src_mac = new MacAddress("08:00:27:00:9C:80").getAddress(); 
     // MAC Address of machine running web server 
     ether.dst_mac = new MacAddress("08:00:27:C7:D2:4C").getAddress(); 

     //set the datalink frame of the packet as ether 
     packet.datalink=ether; 

     //send the packet 
     sender.sendPacket(packet); 

     sender.close(); 

     //just print out a captured packet 
     System.out.println(packet); 
    } 
} 

任何幫助將不勝感激。謝謝。

Answer 1

爲什麼？他的原因是什麼？他是否真的想爲你已經完成的同樣事情付出十倍的成本？

您不需要Jpcap來實現HTTP代理。它可以完全在java.net或java.nio中完成。

Answer 2

我不認爲你可以做到這一點，至少在Windows的盒子。 JPCAP僅僅是Winpcap的包裝，而這背後的機制不能刪除觀察數據包：

http://www.mirrorservice.org/sites/ftp.wiretapped.net/pub/security/packet-capture/winpcap/misc/faq.htm#Q-17

所以，我不知道如何建立一個反向代理「上線」。難道你必須做到以下幾點：

1. 通過分組拼湊在實時和由預期的主機接收投下他們觀察傳入的HTTP請求。

2. 根據您正在實施的任何代理規則進行備用HTTP請求。

3. 從您的請求中獲取響應，並在假冒原始主機響應的線路上推送數據包？

既然你不能丟棄入站數據包，那麼預定的主機是不是會試圖處理請求並將它自己的數據包扔到網絡上作爲響應？因爲我不是網絡專家，所以我可能還不知道更多。這個問題讓我對使用這種「墊片」有可能會有什麼好奇。