dpnaa2: announce transmit checksum support
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Authored by tuexen on Jan 21 2026, 7:50 AM.

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dsl
timo.voelker_fh-muenster.de

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rGf31336b3e314: dpnaa2: announce transmit checksum support

Summary

Let the network stack know that the NIC supports checksum offloading for the IPv4 header checksum and the TCP and UDP transport checksum. This avoids the computation in software and therefore provides the expected performance gain.

This is in relation to PR 292006.

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rG FreeBSD src repository

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tuexen created this revision.Jan 21 2026, 7:50 AM

Herald added a subscriber: imp. · View Herald TranscriptJan 21 2026, 7:50 AM

tuexen requested review of this revision.Jan 21 2026, 7:50 AM

Based on Dmitry's explanation

https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=292006#c26

the driver instructs the nic to compute and insert the checksum for all packets if IFCAP_TXCSUM or IFCAP_TXCSUM_IPV6 is enabled. However, without setting hwassist FreeBSD computes the checksum in software already.

I haven't tested it but, based on the code, this patch should prevent FreeBSD from computing the checksum in software if the nic does it in hardware.

This revision is now accepted and ready to land.Thu, Jan 22, 3:27 PM

lgtm