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From: "N. Benes" <nbenes@eso.org>
To: dev <dev@dpdk.org>
Subject: [dpdk-dev] Bug in IPv4 header checksum computation?
Date: Mon, 01 Apr 2019 15:29:00 +0000	[thread overview]
Message-ID: <65744706-bc88-f144-f85e-1b0292402cff@eso.org> (raw)
Message-ID: <20190401152900.wTtLiTYj7qhFgiR_HYwQH9R2XY0x8bExBtL2jX-5H5k@z> (raw)

Hi,

I wrote to the users list a bit more a week ago concerning the IPv4
Header Checksum computation and received no comments on it yet:

https://mails.dpdk.org/archives/users/2019-March/004021.html
https://mails.dpdk.org/archives/users/2019-March/004022.html

I have the impression that the current implementation wrongly does a
conditional final inversion of the computed sum. This is correct for
e.g. UDP, but I think it is not for an IPv4 Header (header checksum is
not optional).

If it is a bug, this could result in a surprisingly high number of
invalid/dropped IPv4 packets, when the checksum is calculated manually
via the DPDK API (not NIC-offloaded) and the IPv4 header has an
appropriate combination of values e.g. the IP Identification field.

Cheers!

             reply	other threads:[~2019-04-01 15:29 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-01 15:29 N. Benes [this message]
2019-04-01 15:29 ` N. Benes
2019-04-02  7:58 ` Andrew Rybchenko
2019-04-02  7:58   ` Andrew Rybchenko
2019-04-02  8:46   ` Olivier Matz
2019-04-02  8:46     ` Olivier Matz

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