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Date: Wed, 12 Nov 1997 10:21:19 -0600 (CST)
From: Mark Tinguely <tinguely@plains.NoDak.edu>
Message-Id: <199711121621.KAA29115@plains.NoDak.edu>
To: aalves@dei.uc.pt
Subject: Re: ATM driver & udp stream
Cc: freebsd-atm@FreeBSD.ORG
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I did something simular in my IDT NICStAR drive, except I changed the
MBUF routine to keep a permanent association between the MBUF and its
external data buffer.

The MBUF virtual address and also the external data physical address are
programmed into the card. Obviously, the external data physical address so
that the card can store the information into the buffer and the MBUF virtual
address to more quickly link this buffer with the rest of the PDU or to
hand the buffer up to the higher protocols.

With the permanent association between an MBUF and its external data buffer,
I keep a seperate free MBUF link list (stored on m_nextpkt) for MBUF that are
not being processed in the stack, nor are programmed in the card for new input.
Since these MBUFs can be quickly recycled, I did not want the MBUF routines
to break the MBUF to external data association only to re-establish it. This
feature also gives me an easy external data to MBUF map function.

--mark.