Bug 254445

Summary: cloned_interfaces="bridge0" does not respect net.inet6.ip6.auto_linklocal
Product: Base System Reporter: John W. O'Brien <john>
Component: confAssignee: freebsd-net (Nobody) <net>
Status: New ---    
Severity: Affects Only Me CC: emaste, hrs, kp, rpaulo
Priority: --- Flags: john: mfc-stable13?
Version: 13.0-STABLE   
Hardware: Any   
OS: Any   
See Also: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=247700

Description John W. O'Brien 2021-03-20 22:15:33 UTC
Expected behavior
-----------------

When creating a IPv6-enabled bridge interface, the AUTO_LINKLOCAL flag will be set automatically, and the interface will be assigned a link-local address.

Observed behavior
-----------------

The IPv6-enabled bridge interface does not have a link-local address, even if a globally-unique address is assigned to affirm the IPv6 intent.

First observed on 12.1-RELEASE amd64, observed again on 12.2-RELEASE-p4 amd64, reproduced on 13.0-RC3 aarch64 EC2 AMI.

Steps to reproduce
------------------

Verify that net.inet6.ip6.auto_linklocal==1.

Set cloned_interfaces="bridge0" and reboot.

Verify that AUTO_LINKLOCAL is not set on bridge0.

Then set ifconfig_bridge0_ipv6="inet6 2001:db8::1/64" and reboot.

Verify that AUTO_LINKLOCAL is not set on bridge0.

Note that AWS AMIs set ipv6_activate_all_interfaces="YES" by default.
Comment 1 Kristof Provost freebsd_committer 2021-03-20 22:44:35 UTC
This appears to be intentional: https://cgit.freebsd.org/src/commit/?id=af8056441e3f7ef883f0682cbbc5ee33d0975c2f

I'm not sure I understand why though, so I've cc'd the original authors.