From a951bc1e6ba58f11df5ed5ddc41311e10f5fd20b Mon Sep 17 00:00:00 2001 From: dingtianhong Date: Thu, 16 Jul 2015 16:30:02 +0800 Subject: [PATCH] bonding: correct the MAC address for "follow" fail_over_mac policy The "follow" fail_over_mac policy is useful for multiport devices that either become confused or incur a performance penalty when multiple ports are programmed with the same MAC address, but the same MAC address still may happened by this steps for this policy: 1) echo +eth0 > /sys/class/net/bond0/bonding/slaves bond0 has the same mac address with eth0, it is MAC1. 2) echo +eth1 > /sys/class/net/bond0/bonding/slaves eth1 is backup, eth1 has MAC2. 3) ifconfig eth0 down eth1 became active slave, bond will swap MAC for eth0 and eth1, so eth1 has MAC1, and eth0 has MAC2. 4) ifconfig eth1 down there is no active slave, and eth1 still has MAC1, eth2 has MAC2. 5) ifconfig eth0 up the eth0 became active slave again, the bond set eth0 to MAC1. Something wrong here, then if you set eth1 up, the eth0 and eth1 will have the same MAC address, it will break this policy for ACTIVE_BACKUP mode. This patch will fix this problem by finding the old active slave and swap them MAC address before change active slave. Signed-off-by: Ding Tianhong Tested-by: Nikolay Aleksandrov Signed-off-by: David S. Miller --- drivers/net/bonding/bond_main.c | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c index 1d26d6700c1d..e1ccefce9a9d 100644 --- a/drivers/net/bonding/bond_main.c +++ b/drivers/net/bonding/bond_main.c @@ -625,6 +625,23 @@ static void bond_set_dev_addr(struct net_device *bond_dev, call_netdevice_notifiers(NETDEV_CHANGEADDR, bond_dev); } +static struct slave *bond_get_old_active(struct bonding *bond, + struct slave *new_active) +{ + struct slave *slave; + struct list_head *iter; + + bond_for_each_slave(bond, slave, iter) { + if (slave == new_active) + continue; + + if (ether_addr_equal(bond->dev->dev_addr, slave->dev->dev_addr)) + return slave; + } + + return NULL; +} + /* bond_do_fail_over_mac * * Perform special MAC address swapping for fail_over_mac settings @@ -652,6 +669,9 @@ static void bond_do_fail_over_mac(struct bonding *bond, if (!new_active) return; + if (!old_active) + old_active = bond_get_old_active(bond, new_active); + if (old_active) { ether_addr_copy(tmp_mac, new_active->dev->dev_addr); ether_addr_copy(saddr.sa_data, -- 2.30.2