WinDivert:在tcp包中更改GET请求。

I'm trying to change simple GET request with pydivert (WinDivert for python)

我尝试用py分流(python的WinDivert)来更改简单的GET请求

What i seem to encounter is problem with packet lenght.
when i rewrite url so it has same amount or less of letters it works:
ie. GET /?a=asdf => GET /?a=z

我似乎遇到的是包的问题。当我重写url时，它有相同数量或更少的字母它工作:ie。GET / ?= asdf = > / ? z =

But when i add more letters to the request, browser loops and ends up without showing anything

但是当我在请求中添加更多的字母时，浏览器就会循环，结果却没有显示任何东西。

Below is example code i use

下面是我使用的示例代码。

filter_ = "true and tcp.PayloadLength > 0" 
with Handle(filter=filter_) as handle:

 while True:

        packet = handle.receive()

        if packet.payload[0:3]=="GET":
            packet.payload=packet.payload.replace("GET /?a=asdf","GET /?a=gfdsazzz")
        handle.send(packet)

and

和

<?php
  echo $_GET['a'];
?>

Is there somewhere a MAX packet size setted. If yes then how to increase it?

是否有某个地方有一个最大的数据包大小。如果是，那么如何增加它?

If that would be a hint for you then if i will print all packets in console then i clearly see that request was responded by server because see packet.payload with gfdsazzz

如果这对你来说是一个提示，那么如果我在控制台上打印所有的包，那么我清楚地看到请求被服务器响应，因为看到了数据包。载荷与gfdsazzz

1 个解决方案

#1

The immediate problem is that you did not update the TCP/IP headers to reflect the new packet length.

最直接的问题是，您没有更新TCP/IP报头以反映新的包长度。

However, there are other more serious problems:

然而，还有其他更严重的问题:

As you mentioned, the new packet may exceed the maximum packet size (MTU)
如您所述，新包可能超过最大数据包大小(MTU)
The TCP Seq/Ack numbers need to be changed, and will no longer be in sync between both ends of the connection.
TCP Seq/Ack数字需要更改，并且将不再在连接的两端同步。
EDIT: Another problem is that the URL may be split between multiple packets, especially for long URLs.
编辑:另一个问题是URL可能会在多个包之间分开，特别是对于长URL。

The second and third problems can not be fixed easily.

第二和第三个问题不容易解决。

If you wish to modify TCP streams with WinDivert, a far better solution is to use WinDivert to redirect the traffic to a local proxy server, and have the proxy server edit the stream. For an example program that uses this idea, see TorWall.

如果您希望使用WinDivert修改TCP流，那么更好的解决方案是使用WinDivert将流量重定向到本地代理服务器，并让代理服务器编辑流。对于一个使用这个想法的示例程序，请参见TorWall。

#1