ipv6 ND and rfc5942

[Andreas Fett <a.fett%gmx.de@localhost>]

Hi,

I recently did some Investigation in RFCs
concerning Ipv6 neigbourhood discovery and
came across rfc5942 (IPv6 Subnet Model: The Relationship
between Links and Subnet Prefixes).

From what I gathered there and in RFCs referenced
therein the fact that a host (as defined by the rfc
to be a node which is not a router) has a non link
local address assigned to one of its interfaces
is not enough reason for it to assume that
all nodes of the same subnet are reachable via this link.

Furthermore to me the RFC seems to indicate that in
absence of the knowledge whether another node resides on
the same link a host is required to send the packet to a
router, or in case it knows no router to generate an
icmp destination unreachable message.

Looking through the code of sys/netinet6 it seems
to me that this is not the way it is implemented
in the NetBSD kernel (nor in any other BSD or the Linux
kernel).

This may bye due to the fact that:
a) I did not understand the RFC(s) correctly
b) the RFC in question is fairly new or
c) that there are valid reasons for not implementing this
behaviour (as it differs considerably from ipv4 behaviour
and the RFC indicates that it is a non issue for ethernet
networks)

I would appreciate to hear your thoughts on this issue.

Andreas

-- 
The three chief virtues of a programmer are:
Laziness, Impatience and Hubris. -- Larry Wall