On Thu, Aug 08, 2013 at 04:02:36PM -0300, Marcelo Ricardo Leitner wrote:

Em 08-08-2013 16:01, Hannes Frederic Sowa escreveu:

quoted

On Thu, Aug 08, 2013 at 02:45:40PM -0400, Debabrata Banerjee wrote:

quoted

On Wed, Jan 30, 2013 at 3:26 AM, Jiri Pirko [off-list ref] wrote:

quoted

From: Marcelo Ricardo Leitner <redacted>

I'm not sure this patch is doing the right thing. It seems to break
IPv6 loopback functionality, it is no longer equivalent to IPv4, as
stated above. It doesn't just stop neighbor creation but it stops
cached route creation. Seems like a scary change for a stable tree.
See below:

$ ip -4 route show local
local 127.0.0.0/8 dev lo  proto kernel  scope host  src 127.0.0.1

This local route enables us to use the whole loopback network, any
address inside 127.0.0.0/8 will work.

$ ping -c1 127.0.0.9
PING 127.0.0.9 (127.0.0.9) 56(84) bytes of data.
64 bytes from 127.0.0.9: icmp_seq=1 ttl=64 time=0.012 ms

--- 127.0.0.9 ping statistics ---

1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.012/0.012/0.012/0.000 ms

This also used to work equivalently for IPv6 local loopback routes:

$ ip -6 route add local 2001:::/64 dev lo
$ ping6 -c1 2001::9
PING 2001::9(2001::9) 56 data bytes
64 bytes from 2001::9: icmp_seq=1 ttl=64 time=0.010 ms

--- 2001::9 ping statistics ---

1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 0.010/0.010/0.010/0.000 ms

However with this patch, this is very broken:

$ ip -6 route add local 2001::/64 dev lo
$ ping6 -c1 2001::9
PING 2001::9(2001::9) 56 data bytes
ping: sendmsg: Invalid argument

--- 2001::9 ping statistics ---

1 packets transmitted, 0 received, 100% packet loss, time 0ms

Which kernel version are you using? Perhaps you miss another fix? It works 
for
me. Also I cannot find this patch in net-next?

It wasn't needed/applied as the route cache was removed.

Do you mean the rt->n(eighbour) removal? There was no removal of a route cache
in IPv6 land. The cache is merely in the routing table itself.

Greetings,

  Hannes