How To access the Data in NDIS_PACKET

NTDEV
1

Hi all,
I am realy a newbie to Kernal mode device drivers.At present i am
developing a packet filter ndis intermediate driver ,which will
encrypt/decrypt the data comming from perticular application to our driver
and decript it accordingly.
Now i have few questions.
1)When i recive the packet what headers this packet will contain ?(i.e
IP,TCP MAC , UDP) in whaich formate they r organised in the packet ? i.e
how many bits each header will take ?..and where actaly is my data will be
stored ?..i mean can i get the starting and ending address of each
header/packet?..

  1. When i am encripting the packet should i encript both header and data
    or only data ?..if so how to do it ?..

  2. Please give me the links where i can find realy good technical
    information about NDIS Intermediate Filter Drivers.

Thanks in advance,

With Best Regards,
Nayak Vinay,

2

See the NDIS.com paper called “NDIS_PACKET Discussion” at the URL:

http://www.ndis.com/papers/default.htm

Also, read the DDK Topics for NDIS_PACKET.

The NDIS.com FAQ has other information that you should read. For example,
the FAQ Topic “Can I modify a NDIS packet That I Didn’t Allocate Myself?” at
the URL:

http://www.ndis.com/faq/default.htm

The choice of modifications (e.g. encryption techniques) is totally up to
you.

Good luck,

Thomas F. Divine
www.pcausa.com

“Nayak” wrote in message news:xxxxx@ntdev…
>
> Hi all,
> I am realy a newbie to Kernal mode device drivers.At present i am
> developing a packet filter ndis intermediate driver ,which will
> encrypt/decrypt the data comming from perticular application to our driver
> and decript it accordingly.
> Now i have few questions.
> 1)When i recive the packet what headers this packet will contain ?(i.e
> IP,TCP MAC , UDP) in whaich formate they r organised in the packet ? i.e
> how many bits each header will take ?..and where actaly is my data will be
> stored ?..i mean can i get the starting and ending address of each
> header/packet?..
>
> 2) When i am encripting the packet should i encript both header and data
> or only data ?..if so how to do it ?..
>
> 3) Please give me the links where i can find realy good technical
> information about NDIS Intermediate Filter Drivers.
>
> Thanks in advance,
>
> With Best Regards,
> Nayak Vinay,
>
>

3

Hi all,
I am realy a newbie to Kernal mode device drivers.At present i am
developing a packet filter ndis intermediate driver ,which will
encrypt/decrypt the data comming from perticular application to our driver
and decript it accordingly.
Now i have few questions.
1)When i recive the packet what headers this packet will contain ?(i.e
IP,TCP MAC , UDP) in whaich formate they r organised in the packet ? i.e
how many bits each header will take ?..and where actaly is my data will be
stored ?..i mean can i get the starting and ending address of each
header/packet?..
please read ddk document, you will find all details about the NDIS_PACKET struct.

  1. When i am encripting the packet should i encript both header and data
    or only data ?..if so how to do it ?..
    the Buffer include MAC head and whole IP packet. You needn’t modify MAC head if you don’t change IP dest addr.

  2. Please give me the links where i can find realy good technical
    information about NDIS Intermediate Filter Drivers.
    just read ddk!

Thanks in advance,

With Best Regards,
Nayak Vinay,

Questions? First check the Kernel Driver FAQ at http://www.osronline.com/article.cfm?id=256

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4

>1)When i recive the packet what headers this packet will

contain ?(i.e
IP,TCP MAC , UDP) in whaich formate they r organised in the

MAC followed by IP followed by UDP or TCP.

Maxim Shatskih, Windows DDK MVP
StorageCraft Corporation
xxxxx@storagecraft.com
http://www.storagecraft.com

5

See if this helps:

http://www.ndis.com/papers/ndispacket/ndispacket1.htm

–
-Farooque Khan
http://www.concretioindia.com

“Maxim S. Shatskih” wrote in message
news:xxxxx@ntdev…
>
> >1)When i recive the packet what headers this packet will
> >contain ?(i.e
> >IP,TCP MAC , UDP) in whaich formate they r organised in the
>
> MAC followed by IP followed by UDP or TCP.
>
> Maxim Shatskih, Windows DDK MVP
> StorageCraft Corporation
> xxxxx@storagecraft.com
> http://www.storagecraft.com
>
>
>