Subject: RE: Hardware IPv4/TCP/UDP checksumming support
To: None <tech-net@netbsd.org, tech-kern@netbsd.org>
From: =?iso-8859-1?Q?P=E5l_Halvorsen?= <paalh@unik.no>
List: tech-kern
Date: 09/06/2001 10:59:58
Dear all,

I have a question about performing checksum operations on the NIC.

Is the packet transmitted to the NIC memory or can the NIC CPU access the
main memory? How does this work eg., when first performing UDP
checksum then inserting IP header fields and then IP header checksum?
Is the header operations also performed by the NIC CPU?

Thanks and best regards,
Paal Halvorsen

>Folks...
>
>I have committed my changes to support in-bound and out-bound IPv4, TCP,
>and UDP checksumming to NetBSD-current.  It is currently supported on the
>NatSemi DP83820 Gigabit Ethernet (gsip), 3Com Etherlink XL (ex), and
>Alteon Tigon/Tigon2 Gigabit Ethernet (ti).  There is also support for
>caching the IPv6 TCP pseudo-header checksum, which should save some CPU
>time for IPv6 users, as well.
>
>Please report any problems you experience with this code via send-pr(1).
>
>Shar and enjoy!
>
>-- 
>        -- Jason R. Thorpe <thorpej@zembu.com>


-ph
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 | / | Paal Halvorsen   UniK - Center for technology at Kjeller | \ |
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