Bonding in balance-alb mode records information from ARP packets
passing through the bond in a hash table (rx_hashtbl).
At certain situations (e.g. link change of a slave),
rlb_update_rx_clients() will send out ARP packets to update ARP
caches of other hosts on the network to achieve RX load
balancing.
The problem is that once an IP address is recorded in the hash
table, it stays there indefinitely. If this IP address is
migrated to a different host in the network, bonding still sends
out ARP packets that poison other systems' ARP caches with
invalid information.
This patch solves this by looking at all incoming ARP packets,
and checking if the source IP address is one of the source
addresses stored in the rx_hashtbl. If it is, but the MAC
addresses differ, the corresponding hash table entries are
removed. Thus, when an IP address is migrated, the first ARP
broadcast by its new owner will purge the offending entries of
rx_hashtbl.
The hash table is hashed by ip_dst. To be able to do the above
check efficiently (not walking the whole hash table), we need a
reverse mapping (by ip_src).
I added three new members in struct rlb_client_info:
rx_hashtbl[x].src_first will point to the start of a list of
entries for which hash(ip_src) == x.
The list is linked with src_next and src_prev.
When an incoming ARP packet arrives at rlb_arp_recv()
rlb_purge_src_ip() can quickly walk only the entries on the
corresponding lists, i.e. the entries that are likely to contain
the offending IP address.
To avoid confusion, I renamed these existing fields of struct
rlb_client_info:
next -> used_next
prev -> used_prev
rx_hashtbl_head -> rx_hashtbl_used_head
(The current linked list is _not_ a list of hash table
entries with colliding ip_dst. It's a list of entries that are
being used; its purpose is to avoid walking the whole hash table
when looking for used entries.)
Signed-off-by: Jiri Bohac <jbohac@suse.cz>
Signed-off-by: Jay Vosburgh <fubar@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The bonding debugfs support has been broken in the presence of network
namespaces since it has been added. The debugfs support does not handle
multiple bonding devices with the same name in different network
namespaces.
I haven't had any bug reports, and I'm not interested in getting any.
Disable the debugfs support when network namespaces are enabled.
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch provices the debugfs interface to see RLB hash table
like the following:
# cat /sys/kernel/debug/bonding/bond0/rlb_hash_table
SourceIP DestinationIP Destination MAC DEV
10.124.196.205 10.124.196.205 ff:ff:ff:ff:ff:ff eth4
10.124.196.205 10.124.196.81 00:19:99:XX:XX:XX eth3
10.124.196.205 10.124.196.1 00:21:d8:XX:XX:XX eth0
This is helpful to check if the receive load balancing works as expected.
Signed-off-by: Taku Izumi <izumi.taku@jp.fujitsu.com>
Signed-off-by: Jay Vosburgh <fubar@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch provides the debugfs facility to the bonding driver.
The "bonding" directory is created in the debugfs root and directories of
each bonding interface (like bond0, bond1...) are created in that.
# mount -t debugfs none /sys/kernel/debug
# ls /sys/kernel/debug/bonding
bond0 bond1
Signed-off-by: Taku Izumi <izumi.taku@jp.fujitsu.com>
Signed-off-by: Jay Vosburgh <fubar@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
