wireless lan, defragmentation in driver module.

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Hi,

I need help in the following issue, i'll explain the mechanisum & the problem i'm facing,

1) In the existing wireless lan driver we've MPDU's & MSDU's, all the MPDU's are handled by the firmware where as all the MSDU's by the driver. Now i need to implement 802.11E protocol based block ack mechanisum, in this mechanisum ther will not be any wirelss ack's for each MPDU's insted the Transmitter can request for Blockack by transmitting BlockAck.request , for which the receiver will respond with an block ack by indication all the lost mpdu's. The MSDU's given by the driver/os can be fragmented in the MAC(by firmware) if the packet is exceeding the fragmentation threshold limit. Previously the defragmentation was done in firmware but as firmware is lacking memory we've to move the de-fragmentation (only in block ack mechansum) into driver. In the old driver this was not a problem because driver will get only MSDU's & not MPDU's. So that i can happely copy these packets from our h/w queue into an sk_buff & give it to OS, a) in the present case i cannot do this if block.ack mechanisum was established, i'll get only mpdu's & i've to assemble it & form the MSDU's. b) I'll have a scheduler who'll come & take these packets from my software queue's & give it to OS.

So i need to know
a) whenever i've 10mpdu's of an MSDU from Station A to be transmitted into StationB

A                                 B

mpdu1---------------->Success
mpdu2---------------->Success
mpdu3---------------->Success
mpdu4---------------->Failed
mpdu5---------------->Success
mpdu6---------------->Success
mpdu7---------------->Failed
mpdu8---------------->Success
mpdu9---------------->Failed
mpdu10---------------->Success

mpdu's 3, 7 & 9 are lost this we'll indicate in the block-acksent whenever transmitter is requesting for block ack using blockack.request , but in the receiver all these mpdu's has to be stored untill station A succesfully transmits all the lost mpdu's. Once these mpdu's are received correctly i've to put these mpdu's in the correct position & form the MSDU, then only i can give this MSDU to OS.

This is the scenario which can happen in a simple MSDU transfer from station A to B.
------------------------------------------------------------------------------------------------------------------------
Is it possible to allocate one skbuff for one packet (this will be mainatained in my s/w queues), as & when some mpdu's come i'll insert it in the correct offset ??Weather any kernel calls are available for manipulating skbuff. i searched in net/core.c but i was not sure weather this can be used in my own de-fragmentation mechanism...

Or should i directly maintain my own buffers & copy it only in the end to a single skbuff, i dont think this a good way coz this will decrease the performance of the mechanisum !!!
Can anyone help me !

Regards,
P.Lavin


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