使用Jpcap创建反向代理 [英] Creating a Reverse Proxy using Jpcap

问题描述

我需要创建一个接收HTTP请求的程序，并将这些请求转发给Web服务器。

I need to create a program that receives HTTP request and forwards those requests to the web servers.

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

我已成功使用Java套接字，但客户端需要在Jpcap中实现该程序。我想知道这是否可行以及我应该为这个项目阅读哪些文献。

I have successfully made this using only Java Sockets but the client needed the program to be implemented in Jpcap. I'd like to know if this is possible and what literature I should be reading for this project.

这就是我现在通过将Jpcap教程中的各个部分拼接在一起的原因：

This is what I have now by stitching together pieces from the Jpcap tutorial:

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);
    }
}

任何帮助都将不胜感激。谢谢。

Any help would be greatly appreciated. Thank you.

推荐答案

为什么？他的理由是什么？他是否真的想为你已经完成的事情支付十倍的费用？

Why? What are his reasons? Does he really want to pay ten times the cost for the same thing you've already done?

你不需要Jpcap来实现HTTP代理。它可以完全在java.net或java.nio中完成。

You don't need Jpcap to implement HTTP proxies. It can be done entirely within java.net or java.nio.

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