[PATCH net-next v4 3/4] net: bonding: send peer notify when failure recovery

Tonghao Zhang
2025-05-14T09:27:04Z

After LACP protocol recovery, the port can transmit packets.
However, if the bond port doesn't send gratuitous ARP/ND
packets to the switch, the switch won't return packets through
the current interface. This causes traffic imbalance. To resolve
this issue, when LACP protocol recovers, send ARP/ND packets.

Cc: Jay Vosburgh <jv@jvosburgh.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: Simon Horman <horms@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Andrew Lunn <andrew+netdev@lunn.ch>
Signed-off-by: Tonghao Zhang <tonghao@bamaicloud.com>
Signed-off-by: Zengbing Tu <tuzengbing@didiglobal.com>
---
Documentation/networking/bonding.rst | 5 +++--
drivers/net/bonding/bond_3ad.c | 13 +++++++++++++
drivers/net/bonding/bond_main.c | 21 ++++++++++++++++-----
3 files changed, 32 insertions(+), 7 deletions(-)

diff --git a/Documentation/networking/bonding.rst b/Documentation/networking/bonding.rst
index 14f7593d888d..f8f5766703d4 100644
--- a/Documentation/networking/bonding.rst
+++ b/Documentation/networking/bonding.rst
@@ -773,8 +773,9 @@ num_unsol_na
greater than 1.

The valid range is 0 - 255; the default value is 1. These options
- affect only the active-backup mode. These options were added for
- bonding versions 3.3.0 and 3.4.0 respectively.
+ affect the active-backup or 802.3ad (broadcast_neighbor enabled) mode.
+ These options were added for bonding versions 3.3.0 and 3.4.0
+ respectively.

From Linux 3.0 and bonding version 3.7.1, these notifications
are generated by the ipv4 and ipv6 code and the numbers of
diff --git a/drivers/net/bonding/bond_3ad.c b/drivers/net/bonding/bond_3ad.c
index c6807e473ab7..d1c2d416ac87 100644
--- a/drivers/net/bonding/bond_3ad.c
+++ b/drivers/net/bonding/bond_3ad.c
@@ -982,6 +982,17 @@ static int ad_marker_send(struct port *port, struct bond_marker *marker)
return 0;
}

+static void ad_cond_set_peer_notif(struct port *port)
+{
+ struct bonding *bond = port->slave->bond;
+
+ if (bond->params.broadcast_neighbor && rtnl_trylock()) {
+ bond->send_peer_notif = bond->params.num_peer_notif *
+ max(1, bond->params.peer_notif_delay);
+ rtnl_unlock();
+ }
+}
+
/**
* ad_mux_machine - handle a port's mux state machine
* @port: the port we're looking at
@@ -2061,6 +2072,8 @@ static void ad_enable_collecting_distributing(struct port *port,
__enable_port(port);
/* Slave array needs update */
*update_slave_arr = true;
+ /* Should notify peers if possible */
+ ad_cond_set_peer_notif(port);
}
}

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 37340db6512b..21acde5309fb 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1242,17 +1242,28 @@ static struct slave *bond_find_best_slave(struct bonding *bond)
/* must be called in RCU critical section or with RTNL held */
static bool bond_should_notify_peers(struct bonding *bond)
{
- struct slave *slave = rcu_dereference_rtnl(bond->curr_active_slave);
+ struct bond_up_slave *usable;
+ struct slave *slave = NULL;

- if (!slave || !bond->send_peer_notif ||
+ if (!bond->send_peer_notif ||
bond->send_peer_notif %
max(1, bond->params.peer_notif_delay) != 0 ||
- !netif_carrier_ok(bond->dev) ||
- test_bit(__LINK_STATE_LINKWATCH_PENDING, &slave->dev->state))
+ !netif_carrier_ok(bond->dev))
return false;

+ if (BOND_MODE(bond) == BOND_MODE_8023AD) {
+ usable = rtnl_dereference(bond->usable_slaves);
+ if (!usable || !READ_ONCE(usable->count))
+ return false;
+ } else {
+ slave = rcu_dereference_rtnl(bond->curr_active_slave);
+ if (!slave || test_bit(__LINK_STATE_LINKWATCH_PENDING,
+ &slave->dev->state))
+ return false;
+ }
+
netdev_dbg(bond->dev, "bond_should_notify_peers: slave %s\n",
- slave ? slave->dev->name : "NULL");
+ slave ? slave->dev->name : "all");

return true;
}
--
2.34.1