Re: IPv6 networking problems in 14.3

Okay.  Apologies to those who like the whole thread to be in each email, but
I’m starting again here after a discovery.

I rebooted my router after copying the 14.1p5 kernel I was running earlier,
and while the system failed to come up very well (due to 14.3 userland), I
was able to manually start up dhcpcd, the same actual binary, and it was
able to set up my IPv6 connectivity through my ISP just like before.  So
there’s a regression here.  Or something subtle I need to change that I
am so far missing.

Summary:
When booted with FreeBSD 14.3-RELEASE-p2, dhcpcd gets an RA from my ISP,
sends a NS, but never gets the NA response.  Therefore no outgoing packets
ever get out.

% ndp -an | grep vlan0
fe80::3e8a:b0ff:fe3e:4dce%vlan0      (incomplete)       vlan0 1s        I 
fe80::6e8:e675:f359:3465%vlan0       a4:53:0e:79:b9:82  vlan0 permanent R
% tail /var/log/dhcpcd.log
Sep 15 14:03:14 [10047]: vlan0: soliciting an IPv6 router
Sep 15 14:03:14 [10047]: vlan0: sending Router Solicitation
Sep 15 14:03:14 [10047]: vlan0: Router Advertisement from fe80::3e8a:b0ff:fe3e:4dce
Sep 15 14:03:14 [10047]: vlan0: executing: /usr/local/libexec/dhcpcd-run-hooks ROUTERADVERT
Sep 15 14:03:17 [10047]: vlan0: fe80::3e8a:b0ff:fe3e:4dce is unreachable
[...]

When booting with 14.1-RELEASE-p5, dhcpcd works as expected:

% cat 14.1-ndp-success
fe80::3e8a:b0ff:fe3e:4dce%vlan0      3c:8a:b0:3e:4d:ce  vlan0 29s       R R
fe80::a653:eff:fe79:b982%vlan0       a4:53:0e:79:b9:82  vlan0 permanent R 
% (lines from dhcpcd.log)
Sep 15 13:50:44 [57415]: vlan0: soliciting an IPv6 router
Sep 15 13:50:44 [57415]: vlan0: sending Router Solicitation
Sep 15 13:50:44 [57415]: vlan0: Router Advertisement from fe80::3e8a:b0ff:fe3e:4dce
Sep 15 13:50:44 [57415]: vlan0: no global addresses for default route
Sep 15 13:50:44 [57415]: vlan0: executing: /usr/local/libexec/dhcpcd-run-hooks ROUTERADVERT
Sep 15 13:50:45 [57415]: vlan0: multicasting REBIND6 (xid 0x142ec7), next in 1.1 seconds
Sep 15 13:50:45 [57415]: vlan0: REPLY6 received from fe80::3e8a:b0ff:fe3e:4dce
Sep 15 13:50:45 [57415]: vlan0: renew in 3600, rebind in 5760, expire in 7200 seconds
Sep 15 13:50:45 [57415]: vlan0: writing lease: /var/db/dhcpcd/vlan0.lease6
Sep 15 13:50:45 [57415]: vlan0: delegated prefix 2600:4040:2c9d:5200::/56
[...]
Sep 15 13:50:45 [57415]: vlan0: adding default route via fe80::3e8a:b0ff:fe3e:4dce
[...]
Sep 15 13:50:45 [57415]: vlan0: executing: /usr/local/libexec/dhcpcd-run-hooks REBIND6
Sep 15 13:50:45 [56455]: forked to background
[...]

So.  What other information can I help gather?  I might be able to run tcpdump
when I’m up in 14.1 kernel, though the system is kinda broken in a number of
ways.  Let me know anything else I can gather to help track this regression.

-Chris