In a nutshell, data going to and from the application is stored
in memory (either RAM or Flash). When the packet driver sends a packet,
it sends the payload part of the data from the same memory that the application
provided to be sent. When the packet driver receives data, the payload is
passed to the application in the same memory that it came in to from the MAC.
There can be significant improvement of program performance by not copying,
especially when sending or receiving lots of data. This is true from both ends
of the spectrum – low speed processors which take a lot of time to simply
copy memory and very high speed processors where a memory copy is slow because
of the relatively slow speed of memory and not because the speed of the
processor.
Bill
From: address@hidden
[mailto:address@hidden On Behalf
Of Francois Bouchard
Sent: Friday, February 13, 2009 10:16 AM
To: Mailing list for lwIP users
Subject: Re: [lwip-users] Hello to mailinglist
What exactly
is zero-copy rx/tx?
-----
Original Message -----
Sent: Friday, February 13,
2009 9:52 AM
Subject: Re: [lwip-users]
Hello to mailinglist
I suppose I can post it as a patch on savannah. I forgot, I
also
developed a driver for the on-chip FEC+PHY of FreeScale's MCF5223x. It
does zero-copy receive. I'll post it as well,
please notify me after post... i want to see your implementation for zero-copy
as you know we had some discussions in mailing list regarding zero-copy rx and
also zero-copy tx
But filtering IP
addresses and ports in the driver would be straightforward, wouldn't
it? Just match the appropriate fields from IP header against the
whitelist.
yes, i know... i also suppose is simple...
but i wanted to know if other people has developed a similar feature...
i know that is not a robust protection against hacking attack, but it could
mitagate them,
and it could be an interesting feature for the marketing (just label on the
box: "built-in firewall")
thanks for your reply
bye
Piero
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