bin/54997: dhcpcd does not set IPv6 default route

[rcbixler%nyx.net@localhost]

>Number:         54997
>Category:       bin
>Synopsis:       dhcpcd does not set IPv6 default route
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    bin-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Fri Feb 21 18:30:00 +0000 2020
>Originator:     Roy Bixler
>Release:        9
>Organization:
>Environment:
NetBSD localhost 9.0 NetBSD 9.0 (GENERIC) #0: Fri Feb 14 00:06:28 UTC 2020  mkrepro%mkrepro.NetBSD.org@localhost:/usr/src/sys/arch/amd64/compile/GENERIC amd64
>Description:
I have dhcpcd set to YES in my rc.conf.  Networking is set up fine for IPv4 but remote IPv6 connections don't work on startup.  Local IPv6 connections work fine.  The only error I see in the log is:

Feb 21 17:46:53 localhost dhcpcd[276]: axe0: failed to request information

Doing a bit of debug, I see no default router set:

localhost# ndp -r

In the routing table, there is one set, but it is not the active router and does not forward packets.

>How-To-Repeat:
Here are my rc.conf settings:

dhcpcd=YES
dhcpcd_flags="-qM axe0"

I notice remote IPv6 connections don't work:

localhost$ telnet yahoo.com www
Trying 2001:4998:44:41d::3...
telnet: Connect to address 2001:4998:44:41d::3: : Connection timed out

>Fix:
No fix, but I found a workaround.  First, I do:

localhost# ndp -i axe0 accept_rtadv
linkmtu=0, maxmtu=0, curhlim=64, basereachable=30s0ms, reachable=39s, retrans=1s0ms
Flags: nud accept_rtadv override_rtadv 

Wait a bit for "ndp -r" to show a router, then do "ndp -H".  Then the telnet command above connects immediately.