bin/53655: ifwatchd(8) should handle IPv6 "deprecated" interface flags

[clare%csel.org@localhost]

>Number:         53655
>Category:       bin
>Synopsis:       ifwatchd(8) should handle IPv6 "deprecated" interface flags
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    bin-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Sun Oct 07 08:00:00 +0000 2018
>Originator:     Shinichi Doyashiki
>Release:        NetBSD 8.0_RC1
>Organization:
		at home
>Environment:
System: NetBSD kotori.csel.org 8.0_RC1 NetBSD 8.0_RC1 (CONOHA_8) #1: Wed Jun 6 21:10:04 JST 2018 clare%mizuki.csel.org@localhost:/export/stage/stable-8/src/sys/arch/amd64/compile/CONOHA_8 amd64
Architecture: x86_64
Machine: amd64
>Description:
	in Japan, LTE based ISPs does not provide fixed IPv6 prefix for
	general consumers.  power-cycling of LTE routers are result in
	changed (upstream) IPv6 prefix.

	ifwatchd(8) can be used for IPv6 prefix tracking,
	but it does not honor IPv6 DEPRECATED interface flags.

	I want to do is following script:

#!/bin/sh
iface=$1
tty=$2
speed=$3
ifaddr=$4
dest=$5

case "$iface" in
vlan30)
  case "$ifaddr" in
  fe80:*) ;;
  *.*) ;;
  *:*)
    /sbin/ifconfig ipsec0 inet6 tunnel $ifaddr 2400:8500:1302:823::DEAD:BEEF
    /sbin/ifconfig ipsec0 up
    ;;
  esac
  ;;
esac

>How-To-Repeat:
	buy an IPv6 enabled LTE wireless router,
	attach it to an NetBSD box with IPv6 RA-acceptable,
	run ifwatchd(8),
	power-cycle the upsteram LTE router,
	see result of ifwatchd(8).
>Fix:
	unknown yet.