sys/net: move DOT1Q_VID_* constants to ethernet.h
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Authored by ivy on May 28 2025, 10:46 AM.

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des
kevans
zlei
kib
kp

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rG533c0d345b93: sys/net: move DOT1Q_VID_* constants to ethernet.h

Summary

These are generally useful to anything dealing with 802.1q and aren't
specific to if_vlan, so move them to <net/ethernet.h> and remove the
_KERNEL gate.

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rG FreeBSD src repository

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Buildable 64501
Build 61385: arc lint + arc unit

Event Timeline

ivy created this revision.May 28 2025, 10:46 AM

Herald added subscribers: glebius, melifaro, ae, imp. · View Herald TranscriptMay 28 2025, 10:46 AM

ivy requested review of this revision.May 28 2025, 10:46 AM

Harbormaster completed remote builds in B64497: Diff 156166.May 28 2025, 10:46 AM

specifically, i want to use these in ifconfig(8) for D50503.

There should be tab, and not space, between '#define' and the starting char of the symbol.

sys/net/ethernet.h
88	What do DEF_PVID and DEF_SR_PVID mean?

ivy added inline comments.May 28 2025, 2:09 PM

sys/net/ethernet.h
88	i had the same question, and it turns out these come from 802.1Q-2014 table 9-2: 1 is "The default PVID value used for classifying frames on ingress through a Bridge Port." 2 is "The default SR_PVID value used for SRP (35.2.1.4(i)) Stream related traffic." i will add some comments for these.

add some comments.

also fix the value of DOT1Q_VID_MAX, which has been wrong since it was
introduced: it should be 0xffe (4094), not 0xfff (4095). it doesn't
seem to be used anywhere (yet) where this would have any actual impact.

Harbormaster completed remote builds in B64501: Diff 156193.May 28 2025, 2:33 PM

In D50570#1154418, @kib wrote:

There should be tab, and not space, between '#define' and the starting char of the symbol.

they are tabs here. perhaps phabricator doesn't render them properly?

ivy mentioned this in D50503: bridge: add vlan filtering support.May 28 2025, 2:53 PM

ivy added a child revision: D50503: bridge: add vlan filtering support.

rebase on top of D50576. this moves the DOT1Q_VID_MAX fix to a separate commit so it can be MFC'd.

Harbormaster completed remote builds in B64504: Diff 156196.May 28 2025, 3:17 PM

ivy added a parent revision: D50576: if_vlan_var.h: fix value of DOT1Q_VID_MAX.May 28 2025, 3:18 PM

kib added inline comments.May 28 2025, 3:45 PM

sys/net/ethernet.h
88	PVID and SR_PVID repeated in comments do not explain much. My instance of 802.1Q pdf says PVID port VLAN Identifier SR_PVID Stream Reservation Port VLAN Identifier And from what I understand, PVID is the vlan assigned to packets without vlan tag.

kp accepted this revision.May 28 2025, 3:47 PM

This revision is now accepted and ready to land.May 28 2025, 3:47 PM

ivy added inline comments.May 28 2025, 4:05 PM

sys/net/ethernet.h
88	i'm not sure we want to reproduce all of 802.1q in the comments :-) at least there's now enough information for an interested reader to look up more detail. yes, PVID is the VLAN untagged packets go to, but DEF_PVID is only the default PVID, i.e., if the admin doesn't configure it. the default pvid in bridge(4) is effectively 0 (not 1) and we can't easily change that without breaking everyone's bridges, so i'm not sure we will ever use this... but it doesn't hurt to have it.