hi again,
Thanks. Atlast got to the kernel.I defined the new
NEWSOCKETIOCTL in sockios.h. I wrote a dummy function
in af_inet.c and it works when the socket ioctl call
is made.
After passing the argument in
ioctl(socketfd,NEWSOCKIOCTL,NULL) now the next thing I
want to do is to pass an argument to the ioctl
call.I passed a NULL in the first dummy example. Now
if I need to send reference to my own structure,how do
i access this user space argument inside af_inet.c? Or
do I need to write a translating function which
converts the user data from user to kernel space? I
want the socket ioctl call to be application
independent. And I am currently planning to try the
new IOCTL for TCP/IP only.
Thanx again.
Anil
--- Gigi Sullivan <sullivan@sikurezza.org> wrote:
> Aiee :)
>
> Hello!
>
> On Mon, Sep 17, 2001 at 10:40:42AM -0700, Anil Kumar
> wrote:
> > hi all,
> > I wanted to know how I can write my own socket
> > ioctl call. I have to add a new one for the
> socket
> > option in the kernel.
>
> Which socket family? (I suppose AF_INET about
> what follows)
>
> [snip]
> > But from the user program which ioctl function
> > shall I use? Can I use sock_ioctl()? Or will
> ioctl()
>
> You can't use sock_ioctl() from userland since
> it's a kernel
> function; you have to use the usual ioctl(2)
> call.
>
> Moroever sock_ioctl() is just a simple wrapper
> for the real
> socket dependant ioctl call (through function
> pointers - as
> usual within the kernel code).
>
> > The command should also be implemented somewhere.
> > I think af_inet.c for TCP/IP. But I want it to be
> > protocol independent so that I can write different
> > handlers for different protocols. So where do I
> define
> > the new ioctl ??
>
> Look at net/ipv4/af_inet.c, inet_ioctl() funtion
> [1]
> That gets called for SOCK_DGRAM, SOCK_STREAM and
> SOCK_RAW
> socket type, family AF_INET.
>
> inet_ioctl() gets mapped upon socket creation
> (using the
> right proto_ops{} variable - this rapresent a
> `layer'
> between the `userspace view' of a socket and the
> first
> in kernel `struct socket'.
>
> If you think your custom ioctl call has to be
> protocol dependant,
> you should go deeply, adding your code to the
> right .c file (i.e.
> udp.c, raw.c, tcp_ipv4.c and so on).
>
> Look at net/ipv4/af_inet.c to see how the struct
> proto gets filled
> by this `protocol dependant' functions.
>
> This rapresent the second layer between the
> kernel `struct socket'
> and the `struct sock' datatypes.
>
> Well, what I said is, as always, IMHO :)
>
> Obviously feel free to correct this post if I
> said something of wrong,
> not so accurate and so on, thanks!
>
> > Thanx in advance.
> > Anil
> >
> >
> > __________________________________________________
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> >
>
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> > -
> > Kernelnewbies: Help each other learn about the
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> > Archive:
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>
> bye bye
>
> -- gg sullivan
>
> [1]: What I said are just sorta of hints.
> It's not so hard to track down something in the
> kernel, well, better,
> it's not so hard to track down syscall flows in the
> kernel; grep will
> really be your friend :)
>
> --
> Lorenzo Cavallaro `Gigi Sullivan'
> <sullivan@sikurezza.org>
>
> Until I loved, life had no beauty;
> I did not know I lived until I had loved. (Theodor
> Korner)
>
__________________________________________________
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