Re: [PATCH] bonding / ipv6: no addrconf for slaves separately from master

[Jeff Garzik <jeff@garzik.org>]

Jay Vosburgh wrote:
> 	At present, when a device is enslaved to bonding, if ipv6 is
> active then addrconf will be initated on the slave (because it is closed
> then opened during the enslavement processing).  This causes DAD and RS
> packets to be sent from the slave.  These packets in turn can confuse
> switches that perform ipv6 snooping, causing them to incorrectly update
> their forwarding tables (if, e.g., the slave being added is an inactve
> backup that won't be used right away) and direct traffic away from the
> active slave to a backup slave (where the incoming packets will be
> dropped).
> 
> 	This patch alters the behavior so that addrconf will only run on
> the master device itself.  I believe this is logically correct, as it
> prevents slaves from having an IPv6 identity independent from the
> master.  This is consistent with the IPv4 behavior for bonding.
> 
> 	This is accomplished by (a) having bonding set IFF_SLAVE sooner
> in the enslavement processing than currently occurs (before open, not
> after), and (b) having ipv6 addrconf ignore UP and CHANGE events on
> slave devices.
> 
> 	The eql driver also uses the IFF_SLAVE flag.  I inspected eql,
> and I believe this change is reasonable for its usage of IFF_SLAVE, but
> I did not test it.
> 
> Signed-off-by: Jay Vosburgh <fubar@us.ibm.com>

applied