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Differential D51291

tuntap: add IFCAP_TXCSUM and IFCAP_TXCSUM_IPV6
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Authored by timo.voelker_fh-muenster.de on Jul 13 2025, 3:47 PM.
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Details

Reviewers
kevans
tuexen
Summary

Add IFCAP_TXCSUM and IFCAP_TXCSUM_IPV6 to if_capabilities of tun/tap interfaces. If enabled, csum flags are translated into virtio-net header flags. If the virtio-net header is not available, an error gets returned when reading from the character device.
This will be used to add tx checksum offload functionality for a bhyve guest.

Test Plan

Run

ifconfig tap0 create
ifconfig tap0 txcsum txcsum6

and verify using

ifconfig tap0

that the offloading flags are actually set.

Diff Detail

Repository
rG FreeBSD src repository
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Event Timeline

timo.voelker_fh-muenster.de created this revision.Jul 13 2025, 3:47 PM
Herald added subscribers: glebius, melifaro, ae, imp. · View Herald TranscriptJul 13 2025, 3:47 PM
timo.voelker_fh-muenster.de requested review of this revision.Jul 13 2025, 3:47 PM
timo.voelker_fh-muenster.de mentioned this in D51298: tuntap bridge: set tx csum mbuf flags if in a bridge.Jul 14 2025, 10:43 AM
ivy added a subscriber: ivy.Jul 14 2025, 11:08 AM
timo.voelker_fh-muenster.de mentioned this in D51475: sctp, tcp, udp: improve deferred computation of checksums.Jul 23 2025, 12:46 PM
timo.voelker_fh-muenster.de updated this revision to Diff 159595.Aug 1 2025, 8:22 PM

No functional changes. Just modified comments and code style.

timo.voelker_fh-muenster.de mentioned this in D51688: bhyve: add checksum offloading for tap.Aug 1 2025, 8:44 PM
tuexen added a comment.Aug 9 2025, 9:54 PM

@timo.voelker_fh-muenster.de Is it intended that this patch now contains the changes from D51289?

timo.voelker_fh-muenster.de updated this revision to Diff 160168.Aug 10 2025, 9:40 PM

Removed the changes that are in review D51289.

timo.voelker_fh-muenster.de added a comment.Aug 10 2025, 9:41 PM
In D51291#1184658, @tuexen wrote:

@timo.voelker_fh-muenster.de Is it intended that this patch now contains the changes from D51289?

No it wasn't. Thanks for noting.

p.mousavizadeh_protonmail.com added a subscriber: p.mousavizadeh_protonmail.com.Aug 21 2025, 3:11 PM

Revision Contents
Changeset List

PathSize
sys/
net/
18 lines

Diff 160168

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sys/net/if_tuntap.c

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