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Differential D55905

ndp: Accept multiple queued ND for non-GRAND NAs
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Authored by pouria on Mar 17 2026, 8:57 PM.
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glebius
zlei
adrian
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network
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rG15ebee7c2ed3: ndp: Accept multiple queued ND for non-GRAND NAs
Summary

Multiple delayed NAs on the same ifa can occur simultaneously.
Therefore:

  • Differentiate between GRAND and solicited replies.
  • Cancel previous pending GRAND NA for same ifa.
  • Reuse ndq memory for GRAND.
  • Free non-GRAND replies immediately.
  • Don't limit non-GRAND NAs.
Test Plan

Increase grand count before running tests:

sysctl net.inet6.ip6.grand_count=10

then, simply run kyua network tests:

kyua -k /usr/tests/Kyuafile sys/net
kyua -k /usr/tests/Kyuafile sys/netinet6
kyua -k /usr/tests/Kyuafile sys/netlink
kyua -k /usr/tests/Kyuafile sys/netgraph

or you can add multiple v6 addresses followed by changing
the mac address of interface.
Do it in jail and destroy it for stress.

Diff Detail

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rG FreeBSD src repository
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Event Timeline

pouria created this revision.Mar 17 2026, 8:57 PM
Herald added subscribers: melifaro, ae, imp. · View Herald TranscriptMar 17 2026, 8:57 PM
pouria requested review of this revision.Mar 17 2026, 8:57 PM
Harbormaster completed remote builds in B71470: Diff 173827.Mar 17 2026, 8:57 PM
pouria updated this revision to Diff 173828.Mar 17 2026, 10:01 PM

Don't count for grand for delayed solicited NAs.

Harbormaster completed remote builds in B71471: Diff 173828.Mar 17 2026, 10:01 PM
pouria updated this revision to Diff 173829.Mar 17 2026, 11:45 PM

Reuse ndq and cancel out previous pending NA for same ifa.
@glebius done.

Harbormaster completed remote builds in B71472: Diff 173829.Mar 17 2026, 11:45 PM
pouria edited the summary of this revision. (Show Details)Mar 17 2026, 11:47 PM
pouria updated this revision to Diff 173830.Mar 17 2026, 11:53 PM

Fix a minor issue on PATH_MASK.

Harbormaster completed remote builds in B71473: Diff 173830.Mar 17 2026, 11:53 PM
glebius added inline comments.Mar 18 2026, 12:11 AM
sys/netinet6/nd6_nbr.c
1755–1770

This logic can be achieved without new boolean, just using blocks. Also we need not to leak a lock in case of malloc(9) failure.

1863–1864

I would say that previous version was easier to read. A single version of nd6_queue_rel() that requires lock on entry and returns unlocked. Then in this cycle use return; instead of break;. Basically nd6_queue_stop() doesn't need any changes. And second version of nd6_queue_rel_locked() isn't needed.

glebius added a comment.Mar 18 2026, 12:13 AM

I'd suggest to use more specific commit line, e.g. ndp: handle a case when two timers coalesce for the same ifa. Or something else that you can come up with. Just more specific than "make things better" :)

pouria updated this revision to Diff 173874.EditedWed, Mar 18, 11:18 PM

Address @glebius comments and update according to our conversation.

ndp: Accept multiple queued ND for non-GRAND NAs

Multiple delayed NAs on the same ifa can occur simultaneously.
Therefore:
* Differentiate between GRAND and solicited replies.
* Cancel previous pending GRAND NA for same ifa.
* Reuse ndq memory for GRAND.
* Free non-GRAND replies immediately.
* Don't limit non-GRAND NAs.

See also D55927 for one the tests.

Harbormaster completed remote builds in B71499: Diff 173874.Wed, Mar 18, 11:18 PM
pouria retitled this revision from ndp: Improve robustness of nd_queue to ndp: Accept multiple queued ND for non-GRAND NAs.Wed, Mar 18, 11:19 PM
pouria edited the summary of this revision. (Show Details)
pouria edited the summary of this revision. (Show Details)Wed, Mar 18, 11:31 PM
glebius accepted this revision as: glebius.Wed, Mar 18, 11:36 PM
This revision is now accepted and ready to land.Wed, Mar 18, 11:36 PM
pouria mentioned this in D55850: nd6: Fix delayed proxy address.Thu, Mar 19, 2:15 PM
pouria added a child revision: D55850: nd6: Fix delayed proxy address.Thu, Mar 19, 2:16 PM
Closed by commit rG15ebee7c2ed3: ndp: Accept multiple queued ND for non-GRAND NAs (authored by pouria). · Explain WhyThu, Mar 19, 4:23 PM
This revision was automatically updated to reflect the committed changes.
pouria added a commit: rG15ebee7c2ed3: ndp: Accept multiple queued ND for non-GRAND NAs.

Revision Contents
Changeset List

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sys/
netinet6/
6 lines
120 lines

Diff 173932

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sys/netinet6/nd6.h

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sys/netinet6/nd6_nbr.c

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