kern/55074: net/ndp/t_ndp:ndp_rtm test case now fails

[gson%gson.org@localhost (Andreas Gustafsson)]

>Number:         55074
>Category:       kern
>Synopsis:       net/ndp/t_ndp:ndp_rtm test case now fails
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Mar 15 17:30:00 +0000 2020
>Originator:     Andreas Gustafsson
>Release:        NetBSD-current, source date >= 2020.03.09.21.20.56
>Organization:

>Environment:
System: NetBSD
Architecture: x86_64
Machine: amd64
>Description:

On Mar 11, 2020, the NetBSD Test Fixture reported to current-users:

  This is an automatically generated notice of a new failure of the
  NetBSD test suite.

  The newly failing test case is:

      net/ndp/t_ndp:ndp_rtm

Since then, the failure has been narrowed down to the following
commit:

  2020.03.09.21.20.55 roy src/sys/net/route.h 1.127
  2020.03.09.21.20.55 roy src/sys/net/rtsock.c 1.255
  2020.03.09.21.20.55 roy src/sys/netinet/icmp6.h 1.53
  2020.03.09.21.20.55 roy src/sys/netinet/if_arp.c 1.294
  2020.03.09.21.20.56 roy src/sys/netinet6/icmp6.c 1.244
  2020.03.09.21.20.56 roy src/sys/netinet6/nd6.c 1.267
  2020.03.09.21.20.56 roy src/sys/netinet6/nd6_nbr.c 1.177

The test is still failing as of source date 2020.03.15.10.15.16.

>How-To-Repeat:

Run the ATF tests.

>Fix: