Re: TCP library

phil-news-nospam_at_ipal.net
Date: 08/20/03

  • Next message: Jitesh K Patil, Systems Engineer, Wipro Technologies.: "system hang if iopl called before getting pci access structure" 
    Date: 20 Aug 2003 03:09:59 GMT

    On Tue, 19 Aug 2003 08:43:58 +0200 Kasper Dupont <kasperd@daimi.au.dk> wrote:

    |> is it possiple to change the TCP code (i.e init window) and link this to
    |> my program instead of the normal TCP code? I'm not sure cause TCP stuff
    |> belong to the kernel as far as I know. I use Linux RH7.2 and gcc 2.96.
    |
    | With root permissions it is possible to produce raw IP packets, and you
    | can also get the reply packets from the interface. But I would very much
    | advice against that approach. The TCP implementation belongs in the
    | kernel. When the kernel see the unexpected incomming packets, it is going
    | to break the connection with a TCP RST packet.
    |
    | So rather than trying to do anything like this in user mode, you should
    | use whatever options the kernel allow you to change, and otherwise add
    | the needed features to the kernel.

    Problems like the kernel doing TCP RST for you can be avoided by using an
    IP address the kernel will not recognize as belonging to the local stack.
    One way to do this would be to use the TUN/TAP device with your special IP
    address routed to it. Of course you do have to implement the whole TCP/IP
    stack (or at least as much of it you will use and need to react correctly
    on the network) in that userland code. 

    -- 
-----------------------------------------------------------------------------
| Phil Howard KA9WGN       | http://linuxhomepage.com/      http://ham.org/ |
| (first name) at ipal.net | http://phil.ipal.org/   http://ka9wgn.ham.org/ |
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  • Next message: Jitesh K Patil, Systems Engineer, Wipro Technologies.: "system hang if iopl called before getting pci access structure"

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