kern/161899: Repeating RTM_MISS packets causing high CPU load for ntpd

[Gleb Smirnoff]

On Wed, Feb 08, 2012 at 01:44:56PM -0000, Steven Hartland wrote:
S> ----- Original Message ----- 
S> From: "Gleb Smirnoff" <glebius at FreeBSD.org>
S> > > Any update on this, would have been nice to see a fix hit before
S> > > 9.0. If you need any more information please let me know.
S> > 
S> > AFAIK, this is no longer a problem in 9.0-RELEASE or in HEAD.
S> > 
S> > The cause for this number of misses is absense of a route for
S> > IPv4 mapped block in IPv6 routing table.
S> > 
S> > Here it is:
S> > 
S> > # netstat -rn -f inet6 
S> > Routing tables
S> > 
S> > Internet6:
S> > Destination                       Gateway                       Flags      Netif Expire
S> > ::/96                             ::1                           UGRS        lo0
S> > 
S> > Some rc.d script installs this prefix in 9.0 and 10.0. If it hasn't
S> > been merged to stable/8, then it needs to be found and merged.
S> 
S> Thanks Gleb!
S> 
S> Running the following commands does indeed stop this
S> route add -inet6 ::ffff:0.0.0.0 -prefixlen 96 ::1 -reject
S> route add -inet6 ::0.0.0.0 -prefixlen 96 ::1 -reject
S> 
S> I found these in /etc/rc.d/network_ipv6 but I can't see why
S> these wouldnt be run on a machine that doesn't have an IPv6
S> address, they seem to be added correctly on machines that do.
S> 
S> So any pointers are to how to get this fix setup correctly in
S> 8.2 would appreciated.

I don't have any 8.2 where I can play already :) All test boxes
are either head or 9.0.

So it'll be easier to you than to me, to find the exact revision
that is already in stable/9, but not yet in stable/8, that adds
these routes to kernel in startup. Once found, I can do merging.

Meanwhile, I can bounce the PR to freebsd-rc@, and may be someone
from there can find out what needs to be merged.

-- 
Totus tuus, Glebius.