Re: [Programming] kernel level grab packet

From: Shin (gelidmite_at_yahoo.com)
Date: 01/29/04 

Date: 29 Jan 2004 15:02:33 GMT

Well, I might misuse the word 'guard' before.
I am trying to make it clear here.
 
What I want is to implement a program underlying the existing
internet services/applications such as ftp, www, or even higher
level software. Before going to the higher level, packets will
be caught by the program, named P here, and then go where they
should go. Likewise, before going to the physical level, packets
will be caught by P. Then go to the internet.
 
P may do some things on packets, like hashing the contents,
delaying (not dropping) for a while, and etc. Besides, the
one funtionality I need in P is that P can change packet's
destination without higher level application's notice.
 
For example, suppose there are two (or more) any kind of servers,
and one client application C. C only knows one of them, but P
knows all. Under some circumstances, I may hope C's packets go to
the server which C doesn't know. Now, it's time P to work.
I may even add some condtions in P so that P can pick up a server to
connect to automatically.
Combining all the functionalities I mentioned above, I guess kernel
level can meet my need without losing flexibility, since I may
add more functions on P in future.
 
However, I need your help to start in kernel programming for this
program..
Any good online example/tutorial/document?
 
Thanks
Shin

In article <slrnc1ge9l.1aq.gelidmite@localhost.localdomain>, Shin wrote:
> Hi,
> I don't know if I used a good subject because I am not
> familiar with linux kernel programming. I heard it may
> meet my need from someone.
>
> I want to write a program which can filter (or just check)
> internet packets before other applications. It is like
> a guard which collects all internet traffic, even belonging
> to other application, and then pass the packet to where it is
> supposed to go (might be other high level application).
>
> The main point is that these high level applications won't
> notice the guard's existence. I heard programming in kernel
> level can achieve this. After searching the internet, I found
> some materials, but they are not specific enough for my requirement.
>
> I have "Linux Device Drivers, 2nd Edition By Alessandro Rubini &
> Jonathan Corbet". Still reading it. So far, didn't find things
> about what I mentioned above.
>
> Anyone knows good documents/toturial/material for me?
>
> Thanks
>

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