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

[Gary Palmer]

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

Speculation: the machine(s) which didn't have the routes maybe
didn't have

ipv6_enable="YES"

in /etc/rc.conf?

Gary