Currently, we fail only when all of the ips in arp_ip_target are gone.
However, in some situations we might need to fail if even one host from
arp_ip_target becomes unavailable.
All situations, obviously, rely on the idea that we need *completely*
functional network, with all interfaces/addresses working correctly.
One real world example might be:
vlans on top on bond (hybrid port). If bond and vlans have ips assigned
and we have their peers monitored via arp_ip_target - in case of switch
misconfiguration (trunk/access port), slave driver malfunction or
tagged/untagged traffic dropped on the way - we will be able to switch
to another slave.
Though any other configuration needs that if we need to have access to all
arp_ip_targets.
This patch adds this possibility by adding a new parameter -
arp_all_targets (both as a module parameter and as a sysfs knob). It can be
set to:
0 or any (the default) - which works exactly as it's working now -
the slave is up if any of the arp_ip_targets are up.
1 or all - the slave is up if all of the arp_ip_targets are up.
This parameter can be changed on the fly (via sysfs), and requires the mode
to be active-backup and arp_validate to be enabled (it obeys the
arp_validate config on which slaves to validate).
Internally it's done through:
1) Add target_last_arp_rx[BOND_MAX_ARP_TARGETS] array to slave struct. It's
an array of jiffies, meaning that slave->target_last_arp_rx[i] is the
last time we've received arp from bond->params.arp_targets[i] on this
slave.
2) If we successfully validate an arp from bond->params.arp_targets[i] in
bond_validate_arp() - update the slave->target_last_arp_rx[i] with the
current jiffies value.
3) When getting slave's last_rx via slave_last_rx(), we return the oldest
time when we've received an arp from any address in
bond->params.arp_targets[].
If the value of arp_all_targets == 0 - we still work the same way as
before.
Also, update the documentation to reflect the new parameter.
v3->v4:
Kill the forgotten rtnl_unlock(), rephrase the documentation part to be
more clear, don't fail setting arp_all_targets if arp_validate is not set -
it has no effect anyway but can be easier to set up. Also, print a warning
if the last arp_ip_target is removed while the arp_interval is on, but not
the arp_validate.
v2->v3:
Use _bh spinlock, remove useless rtnl_lock() and use jiffies for new
arp_ip_target last arp, instead of slave_last_rx(). On bond_enslave(),
use the same initialization value for target_last_arp_rx[] as is used
for the default last_arp_rx, to avoid useless interface flaps.
Also, instead of failing to remove the last arp_ip_target just print a
warning - otherwise it might break existing scripts.
v1->v2:
Correctly handle adding/removing hosts in arp_ip_target - we need to
shift/initialize all slave's target_last_arp_rx. Also, don't fail module
loading on arp_all_targets misconfiguration, just disable it, and some
minor style fixes.
Signed-off-by: Veaceslav Falico <vfalico@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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