Removing an IPv6 address does not remove NDP entries on that subnet

[Ryan Stone]

On Mon, Apr 9, 2012 at 9:08 PM, Li, Qing <qing.li at bluecoat.com> wrote:
> I have not followed this thread closely from the beginning, so let me confirm.
>
> Are you reporting multiple bugs: 1) ndp entries remain after the removal of
> an address (according to the thread title), and 2) you believe there is a race condition
> around in6_lltable_prefix_free() but if it can never be called, so where is the race condition
> coming from ?

It's all well and good to say that the code can't crash now, but this
is a landmine that somebody's going to step on the first time that
they try to call this function.

> wrt 1), I cannot reproduce the issue, if it's a problem for you, please provide a description
> or just forward me the thread
[rstone at vm-head ~]ping6 -c 1 1::2
PING6(56=40+8+8 bytes) 1::1 --> 1::2
16 bytes from 1::2, icmp_seq=0 hlim=64 time=0.477 ms

--- 1::2 ping6 statistics ---
1 packets transmitted, 1 packets received, 0.0% packet loss
round-trip min/avg/max/std-dev = 0.477/0.477/0.477/0.000 ms
[rstone at vm-head ~]ndp -a
Neighbor                             Linklayer Address  Netif Expire    S Flags
1::1                                 08:00:27:fa:87:32    em0 permanent R
1::2                                 08:00:27:1e:b8:16    em0 25s       R
fe80::a00:27ff:fefa:8732%em0         08:00:27:fa:87:32    em0 permanent R
[rstone at vm-head ~]sudo ifconfig em0 inet6 1::1/64 -alias
[rstone at vm-head ~]ndp -a
Neighbor                             Linklayer Address  Netif Expire    S Flags
1::2                                 08:00:27:1e:b8:16    em0 7s        R
fe80::a00:27ff:fefa:8732%em0         08:00:27:fa:87:32    em0 permanent R
[rstone at vm-head ~]uname -a
FreeBSD vm-head 10.0-CURRENT FreeBSD 10.0-CURRENT #10 r233549:233552M:
Wed Mar 28 10:27:20 EDT 2012
rstone at rstone-laptop:/home/rstone/freebsd/obj/usr/home/rstone/freebsd/head/sys/DTRACE
 amd64