Re: [PATCH net] net: ethernet: ti: am65-cpts: Fix PTPv1 message type on TX packets

[Paolo Abeni]

On Fri, 2024-04-19 at 13:35 +0530, Ravi Gunasekaran wrote:
> From: Jason Reeder <jreeder@xxxxxx>
> 
> The CPTS, by design, captures the messageType (Sync, Delay_Req, etc.)
> field from the second nibble of the PTP header which is defined in the
> PTPv2 (1588-2008) specification. In the PTPv1 (1588-2002) specification
> the first two bytes of the PTP header are defined as the versionType
> which is always 0x0001. This means that any PTPv1 packets that are
> tagged for TX timestamping by the CPTS will have their messageType set
> to 0x0 which corresponds to a Sync message type. This causes issues
> when a PTPv1 stack is expecting a Delay_Req (messageType: 0x1)
> timestamp that never appears.
> 
> Fix this by checking if the ptp_class of the timestamped TX packet is
> PTP_CLASS_V1 and then matching the PTP sequence ID to the stored
> sequence ID in the skb->cb data structure. If the sequence IDs match
> and the packet is of type PTPv1 then there is a chance that the
> messageType has been incorrectly stored by the CPTS so overwrite the
> messageType stored by the CPTS with the messageType from the skb->cb
> data structure. This allows the PTPv1 stack to receive TX timestamps
> for Delay_Req packets which are necessary to lock onto a PTP Leader.
> 
> Signed-off-by: Jason Reeder <jreeder@xxxxxx>
> Signed-off-by: Ravi Gunasekaran <r-gunasekaran@xxxxxx>

Please provide a suitable fixes tag, thanks!

Paolo