Messages in this thread | | | Date | Tue, 28 Apr 2015 15:36:54 -0500 | From | Jaeden Amero <> | Subject | Re: [PATCH RFC] net/macb: Fix UDPv4 checksum offload |
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On 04/27/2015 09:47 PM, David Miller wrote: > From: Jaeden Amero <jaeden.amero@ni.com> > Date: Mon, 27 Apr 2015 17:43:30 -0500 > > A UDP checksum of zero, means "checksum not computed". And your > device isn't computing the checksum at all, but rather is leaving it > at zero.
The "zero" checksum is not what gets sent over the wire. Independent of the value of the checksum field, hardware generates a correct checksum for payloads of 3 or more bytes. The bug is that hardware generates an incorrect checksum for payloads of 2 or less bytes, unless the checksum field is zeroed.
> You need to handle this properly by computing the checksum in > software and then setting the TX descriptor bits such that the > chip leaves the checksum field alone.
Unfortunately, the Cadence MACB doesn't support the enabling or disabling of checksum generation per descriptor.
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