[Divert] Basic questions about functionaly of divert sockets

[Victor F. <vi...@lo...>]

Hello folks,

I am currently working on a divert based filtering software for HTTP requests.
This should work this way:

SERVER -> DIVERT -> CLIENT

The software catches the entire HTTP stream from a server destined for a certain
client and filters it based on several criterias. The main aspect is, that this
is completely transparent, the server sees request coming from the client and
vice versa, the software between is completely invisible. In order to achieve
this, src and dest ip are corrected, but also sequence numbers, etc. Since some
of the HTTP data must be cached before sending it to the client, fake ACK
packets are sent to the server.

Now my questions:
1. What exactly happens to packets reinserted into the TCP stack which cannot be
   delivered to the client ? Do I have to resend them manually, or does the TCP
   stack take care for this ?
2. Is the order of inserted packets relevant ?
3. Does anyone know of a similar software ?

Thank you for your time

Victor Foitzik

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