netinet6: allow binding to anycast addresses
ClosedPublic
Actions

Authored by ivy on Apr 19 2025, 4:42 AM.

Details

Reviewers

kevans
des
adrian

Group Reviewers

network

Commits

rGca4b046105f6: netinet6: allow binding to anycast addresses

Summary

the restriction on sending packets from anycast source addresses was
removed in RFC4291, so there's no reason to forbid binding to such
addresses. this allows anycast services (e.g., DNS) to actually use
anycast addresses, which was previously impossible.

RFC4291 also removes the restriction that only routers may configure
anycast addresses; this was never enforced in code but was documented in
ifconfig.8. update ifconfig.8 to document both changes.

PR: 285545

Diff Detail

Repository

rG FreeBSD src repository

Lint

Lint Not Applicable

Unit

Tests Not Applicable

Event Timeline

ivy created this revision.Apr 19 2025, 4:42 AM

Herald added subscribers: ziaee, glebius, melifaro and 2 others. · View Herald TranscriptApr 19 2025, 4:42 AM

ivy requested review of this revision.Apr 19 2025, 4:42 AM

Harbormaster completed remote builds in B63587: Diff 153906.Apr 19 2025, 4:42 AM

des requested changes to this revision.Apr 19 2025, 10:12 AM

des added inline comments.

sbin/ifconfig/ifconfig.8
31	it's nbd if you don't but try to remember to bump before pushing
452	We should probably add RFC 4291 (and RFC 3484 which is mentioned elsewhere in the page) to the “SEE ALSO” section. See `tcp(4)` or `protocols(5)` for examples of how to format the references.
456	overly verbose, “explicitly binds [a socket] to the address” is enough