bonding: add an option to fail when any of arp_ip_target is inaccessible
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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