Memory allocation in windows kernel driver

Hi all, I'm approaching in the development of windows drivers and I'm
trying to modify the passthru driver provided in the Windows Driver
Development Kit.

In particular I have some problems in memory allocation. I have to
memorize into the passthru driver packets received from driver
Tcpip.sys before sending them through the NIC. Once I have memorized
the bytes of the packets I can send them, but I have also to operate
into the allocated zone of memory modifying its content.

I don't know if I can use the function malloc() to allocate a zone of
memory into the driver because I try to use it but when I build the
driver I have the error unresoved external symbol _imp_malloc
It is possible to create a pointer to an array of pointers to memorize
the packets before sending it? If yes, can I use the function malloc()
to allocate memory?

I read also that the routine ExAllocatePool() is used to allocate pool
memory in windows drivers. Can I use it to memorize a large quantity
of bytes before sending it through the NIC? If yes, what is the
type of pool memory I have to allocate, non paged or paged? I read
that the system can only allocate buffers larger than PAGE_SIZE from
nonpaged pool in multiples of PAGE_SIZE but I don't understand what is
the value of PAGE_SIZE.

Is there anyone that can help me?

Thank you,

Chiara

the equivalent of malloc is ExAllocatePool. I would guess you will need
NonPagedPool. As for what you can allocate, you can do wahtever you want, it
is just C after all. You can allocate any size pointer you want from
NonPagedPool. If you don't know what a page is or what PAGE_SIZE means, you
really should educate yourself before you ever step foot into kernel mode.

d

"chiara" <tchiara81.RemoveThis@libero.it> wrote in message
news:1178363212.228710.118120@w5g2000hsg.googlegroups.com...
> Hi all, I'm approaching in the development of windows drivers and I'm
> trying to modify the passthru driver provided in the Windows Driver
> Development Kit.
>
> In particular I have some problems in memory allocation. I have to
> memorize into the passthru driver packets received from driver
> Tcpip.sys before sending them through the NIC. Once I have memorized
> the bytes of the packets I can send them, but I have also to operate
> into the allocated zone of memory modifying its content.
>
> I don't know if I can use the function malloc() to allocate a zone of
> memory into the driver because I try to use it but when I build the
> driver I have the error unresoved external symbol _imp_malloc
> It is possible to create a pointer to an array of pointers to memorize
> the packets before sending it? If yes, can I use the function malloc()
> to allocate memory?
>
> I read also that the routine ExAllocatePool() is used to allocate pool
> memory in windows drivers. Can I use it to memorize a large quantity
> of bytes before sending it through the NIC? If yes, what is the
> type of pool memory I have to allocate, non paged or paged? I read
> that the system can only allocate buffers larger than PAGE_SIZE from
> nonpaged pool in multiples of PAGE_SIZE but I don't understand what is
> the value of PAGE_SIZE.
>
> Is there anyone that can help me?
>
> Thank you,
>
> Chiara
>