如何在java中的HttpResponse中的代理服务器上获取客户端IP地址？

Question

I am trying to implementing a proxy server in java which will get the HttpRequest from client browser, forward it to server. After receiving HttpResponse from server, it extract cookie and modify the cookie, and then forward HttpResponse with modified cookie to client browser. This I am doing to prevent misuse cookie for session highjacking.

Next time, when client will try to connect the same server, my proxy server will get HttpRequest with this modified cookie. My proxy server will replace this modified cookie by original before forwarding that HttpRequest to server and server will respond as it will detect correct cookie.

One drawback in this approch, if other client of same lan becomes attacker ans steal modified cookie of a client and send HttpRequest to proxy server, proxy server will replace this modified cookie by original and forward to server and attacker will able to perform session highjacking.

To solve this problem, I am trying to implement this in following way.

Instead of (cookie original value= modified value), I will store (Ip, cookie original value)= modified value. So any time HttpReqest comes from client browser I will check Ip address of sender and Ip address stored along with original cookie for this modified cookie.

I have tried to run this code in a Single machine, where I have redirected to all browser request to localport 1111 and I am able to get Client Ip address.

 public static void runServer(String host, int remoteport, int localport)
      throws IOException {

// Create a ServerSocket to listen for connections with
ServerSocket ss = new ServerSocket(1111);

final byte[] request = new byte[1024];
byte[] reply = new byte[4096];

while (true) {
  Socket client = null, server = null;
  try {
    // Wait for a connection on the local port
    client = ss.accept();

    final String SenderIp=client.getInetAddress().getHostAddress();
    System.out.println("Client Ip address "+ SenderIp);

.....

// cookie convertion moodified to original is done here
   (modified cookie ---> original cookie value)
.....



// forward HttpRequest to server 
byte[] requestBytes = requestString.getBytes("ISO-8859-1");
streamToServer.write(requestBytes,0,requestBytes.length);
streamToServer.flush();

}   



// Read the server's responses
        // and pass them back to the client.
        int bytesRead;
        try {
          while ((bytesRead = streamFromServer.read(reply)) != -1) {

        String responseString = new String(reply, 0, bytesRead, "ISO-8859-1");
         System.out.println("Reply string "+responseString);


        // cookie modification done here

        System.out.println("Forwarded to IP "+SenderIp);
        byte[] responseBytes = responseString.getBytes("ISO-8859-1");
        streamToClient.write(responseBytes, 0, responseBytes.length);
        streamToClient.flush();

        HashMap(original_cookie,  modified cookie)
}
}   

How can I know the Ip address to whom this HttpResponse will be sent ? I mean Client Ip address where I will send modify cookie

I want to use HashMap(original_cookie,IP address, modified cookie) after I get HttpResponse from External Server.

Thank you in advance.

Answer 1

I got the solution. I am creating a separate socket between new client and server. So, we can easily retrieve IP address of individual client from the socket between that particular client and server.