kern/49829: point2point network interfaces cannot receive packets

[Takahiro HAYASHI <t.hash425%gmail.com@localhost>]

>Number:         49829
>Category:       kern
>Synopsis:       point2point network interfaces cannot receive packets
>Confidential:   no
>Severity:       critical
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Apr 09 13:35:00 +0000 2015
>Originator:     Takahiro HAYASHI
>Release:        NetBSD 7.99.9
>Organization:
>Environment:
System: NetBSD 7.99.9 amd64
Architecture: x86_64
Machine: amd64
>Description:
	IFF_POINTTOPOINT interfaces like tun and gif cannot
	receive packets.
	This occurs on NetBSD/amd64 -current since Feb 27 2015.

	For example, establishing gif tunnnel between 2 hosts.

[host1] <---> [host2]
192.168.0.1   192.168.0.2  ipv4 address of real interface
fd00::1       fd00::2      gif address

	When I ping6, a host can send ICMPv6 ECHO(128), but the other host
	returns ICMPv6 DST_UNREACH(1) code UNREACH_ADDR(3) to pinging host.
	netstat -nr | grep gif0 is:

fd00::/64                               fd00::1                        UC            0      -  gif0
fd00::1                                 fd00::1                        UHl           5      -  gif0
fe80::%gif0/64                          fe80::216:3eff:fe00:f2         UC            0      -  gif0
fe80::216:3eff:fe00:f2                  fe80::216:3eff:fe00:f2         UHl           0      -  gif0
ff01:3::/32                             fd00::1                        UC            0      -  gif0
ff02::%gif0/32                          fd00::1                        UC            0      -  gif0

	OTOH this problem also happens in v4.
	(see v4 over v6 part of How-To-Repeat)
	"netstat -nr | grep gif0" shows:

192.168.0.1        192.168.0.1        UHl           2      -  gif0
fe80::%gif0/64                          fe80::216:3eff:fe00:f2         UC            0      -  gif0
fe80::216:3eff:fe00:f2                  fe80::216:3eff:fe00:f2         UHl           0      -  gif0
ff01:3::/32                             fe80::216:3eff:fe00:f2         UC            0      -  gif0
ff02::%gif0/32                          fe80::216:3eff:fe00:f2         UC            0      -  gif0

	routes that have RTF_LOCAL do not face to lo0.


>How-To-Repeat:
	In case of v6 over v4:
	ifconfig gif0 create
	ifconfig gif0 fd00::1
	ifconfig gif0 tunnel 192.168.0.1 192.168.0.2
	ping6 -n fd00::1

	In case of v4 over v6:
	ifconfig gif0 create
	ifconfig gif0 192.168.0.1
	ifconfig gif0 tunnel fd00::1 fd00::2
	ping -n 192.168.0.1

>Fix:
	No idea.


-- 
t-hash