Re: [net-next PATCH] net: netlink messages for HW addr programming

On 9/19/16, 7:46 AM, Patrick Ruddy wrote:

On Sun, 2016-09-18 at 07:51 -0700, Roopa Prabhu wrote:

quoted

On 9/15/16, 9:48 AM, Patrick Ruddy wrote:

quoted

Add RTM_NEWADDR and RTM_DELADDR netlink messages with family
AF_UNSPEC to indicate interest in specific unicast and multicast
hardware addresses. These messages are sent when addresses are
added or deleted from the appropriate interface driver.
Added AF_UNSPEC GETADDR function to allow the netlink notifications
to be replayed to avoid loss of state due to application start
ordering or restart.

Signed-off-by: Patrick Ruddy <redacted>
---

RTM_NEWADDR and RTM_DELADDR are not used to add these entries to the kernel.
so, it seems a bit wrong to use RTM_NEWADDR and RTM_DELADDR to notify them to
userspace and also to request a special dump of these addresses.

This could just be a new nested netlink attribute in the existing link dump ?

Hi Roopa

Thanks for the review. I did initially code this using NEW/DEL/GET_LINK
messages but was asked to change to to ADDR messages by Stephen
Hemminger (cc'd). 

However I agree that these addresses fall between the LINK and ADDR
areas so I'm happy to change this if we can reach some consensus on the
format.

ok, thanks for the history. yes, they do lie in a weird spot.
the general convention for other rtnl registrations seems to be
AF_UNSPEC family means include all supported families. thats where this seems a bit odd.

On the other hand, one reason I see where using RTM_*ADDR will be useful for this is if we wanted
to provide a way to add these uc and mc address via ip addr add in the future.
ip addr add <lladdr> dev eth0

Does this patch allow that in the future ?

also, will these l2 addresses now show up in 'ip addr show' output ?.

thanks,
Roopa