[PATCH net-next v4 1/4] net: bonding: add broadcast_neighbor option for 802.3ad

[PATCH net-next v4 1/4] net: bonding: add broadcast_neighbor option for 802.3ad

[Tonghao Zhang]

Stacking technology is a type of technology used to expand ports on
Ethernet switches. It is widely used as a common access method in
large-scale Internet data center architectures. Years of practice
have proved that stacking technology has advantages and disadvantages
in high-reliability network architecture scenarios. For instance,
in stacking networking arch, conventional switch system upgrades
require multiple stacked devices to restart at the same time.
Therefore, it is inevitable that the business will be interrupted
for a while. It is for this reason that "no-stacking" in data centers
has become a trend. Additionally, when the stacking link connecting
the switches fails or is abnormal, the stack will split. Although it is
not common, it still happens in actual operation. The problem is that
after the split, it is equivalent to two switches with the same configuration
appearing in the network, causing network configuration conflicts and
ultimately interrupting the services carried by the stacking system.

To improve network stability, "non-stacking" solutions have been increasingly
adopted, particularly by public cloud providers and tech companies
like Alibaba, Tencent, and Didi. "non-stacking" is a method of mimicing switch
stacking that convinces a LACP peer, bonding in this case, connected to a set of
"non-stacked" switches that all of its ports are connected to a single
switch (i.e., LACP aggregator), as if those switches were stacked. This
enables the LACP peer's ports to aggregate together, and requires (a)
special switch configuration, described in the linked article, and (b)
modifications to the bonding 802.3ad (LACP) mode to send all ARP / ND
packets across all ports of the active aggregator.

  -----------     -----------
 |  switch1  |   |  switch2  |
  -----------     -----------
         ^           ^
         |           |
       -----------------
      |   bond4 lacp    |
       -----------------
         |           |
         | NIC1      | NIC2
       -----------------
      |     server      |
       -----------------

- https://www.ruijie.com/fr-fr/support/tech-gallery/de-stack-data-center-network-architecture/

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 |  6 ++++
 drivers/net/bonding/bond_main.c      | 42 ++++++++++++++++++++++++++++
 drivers/net/bonding/bond_options.c   | 35 +++++++++++++++++++++++
 include/net/bond_options.h           |  1 +
 include/net/bonding.h                |  3 ++
 5 files changed, 87 insertions(+)

diff --git a/Documentation/networking/bonding.rst b/Documentation/networking/bonding.rst
index a4c1291d2561..14f7593d888d 100644
--- a/Documentation/networking/bonding.rst
+++ b/Documentation/networking/bonding.rst
@@ -562,6 +562,12 @@ lacp_rate
 
 	The default is slow.
 
+broadcast_neighbor
+
+	Option specifying whether to broadcast ARP/ND packets to all
+	active slaves.  This option has no effect in modes other than
+	802.3ad mode.  The default is off (0).
+
 max_bonds
 
 	Specifies the number of bonding devices to create for this
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index d05226484c64..37340db6512b 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -212,6 +212,8 @@ atomic_t netpoll_block_tx = ATOMIC_INIT(0);
 
 unsigned int bond_net_id __read_mostly;
 
+DEFINE_STATIC_KEY_FALSE(bond_bcast_neigh_enabled);
+
 static const struct flow_dissector_key flow_keys_bonding_keys[] = {
 	{
 		.key_id = FLOW_DISSECTOR_KEY_CONTROL,
@@ -4461,6 +4463,9 @@ static int bond_open(struct net_device *bond_dev)
 
 		bond_for_each_slave(bond, slave, iter)
 			dev_mc_add(slave->dev, lacpdu_mcast_addr);
+
+		if (bond->params.broadcast_neighbor)
+			static_branch_inc(&bond_bcast_neigh_enabled);
 	}
 
 	if (bond_mode_can_use_xmit_hash(bond))
@@ -4480,6 +4485,10 @@ static int bond_close(struct net_device *bond_dev)
 		bond_alb_deinitialize(bond);
 	bond->recv_probe = NULL;
 
+	if (BOND_MODE(bond) == BOND_MODE_8023AD &&
+	    bond->params.broadcast_neighbor)
+		static_branch_dec(&bond_bcast_neigh_enabled);
+
 	if (bond_uses_primary(bond)) {
 		rcu_read_lock();
 		slave = rcu_dereference(bond->curr_active_slave);
@@ -5316,6 +5325,35 @@ static struct slave *bond_xdp_xmit_3ad_xor_slave_get(struct bonding *bond,
 	return slaves->arr[hash % count];
 }
 
+static bool bond_should_broadcast_neighbor(struct sk_buff *skb,
+					   struct net_device *dev)
+{
+	struct bonding *bond = netdev_priv(dev);
+
+	if (!static_branch_unlikely(&bond_bcast_neigh_enabled))
+		return false;
+
+	if (!bond->params.broadcast_neighbor)
+		return false;
+
+	if (skb->protocol == htons(ETH_P_ARP))
+		return true;
+
+	if (skb->protocol == htons(ETH_P_IPV6) &&
+	    pskb_may_pull(skb,
+			  sizeof(struct ipv6hdr) + sizeof(struct icmp6hdr))) {
+		if (ipv6_hdr(skb)->nexthdr == IPPROTO_ICMPV6) {
+			struct icmp6hdr *icmph = icmp6_hdr(skb);
+
+			if ((icmph->icmp6_type == NDISC_NEIGHBOUR_SOLICITATION) ||
+			    (icmph->icmp6_type == NDISC_NEIGHBOUR_ADVERTISEMENT))
+				return true;
+		}
+	}
+
+	return false;
+}
+
 /* Use this Xmit function for 3AD as well as XOR modes. The current
  * usable slave array is formed in the control path. The xmit function
  * just calculates hash and sends the packet out.
@@ -5583,6 +5621,9 @@ static netdev_tx_t __bond_start_xmit(struct sk_buff *skb, struct net_device *dev
 	case BOND_MODE_ACTIVEBACKUP:
 		return bond_xmit_activebackup(skb, dev);
 	case BOND_MODE_8023AD:
+		if (bond_should_broadcast_neighbor(skb, dev))
+			return bond_xmit_broadcast(skb, dev);
+		fallthrough;
 	case BOND_MODE_XOR:
 		return bond_3ad_xor_xmit(skb, dev);
 	case BOND_MODE_BROADCAST:
@@ -6462,6 +6503,7 @@ static int __init bond_check_params(struct bond_params *params)
 	eth_zero_addr(params->ad_actor_system);
 	params->ad_user_port_key = ad_user_port_key;
 	params->coupled_control = 1;
+	params->broadcast_neighbor = 0;
 	if (packets_per_slave > 0) {
 		params->reciprocal_packets_per_slave =
 			reciprocal_value(packets_per_slave);
diff --git a/drivers/net/bonding/bond_options.c b/drivers/net/bonding/bond_options.c
index 91893c29b899..7f0939337231 100644
--- a/drivers/net/bonding/bond_options.c
+++ b/drivers/net/bonding/bond_options.c
@@ -87,6 +87,8 @@ static int bond_option_missed_max_set(struct bonding *bond,
 				      const struct bond_opt_value *newval);
 static int bond_option_coupled_control_set(struct bonding *bond,
 					   const struct bond_opt_value *newval);
+static int bond_option_broadcast_neigh_set(struct bonding *bond,
+					   const struct bond_opt_value *newval);
 
 static const struct bond_opt_value bond_mode_tbl[] = {
 	{ "balance-rr",    BOND_MODE_ROUNDROBIN,   BOND_VALFLAG_DEFAULT},
@@ -240,6 +242,12 @@ static const struct bond_opt_value bond_coupled_control_tbl[] = {
 	{ NULL,  -1, 0},
 };
 
+static const struct bond_opt_value bond_broadcast_neigh_tbl[] = {
+	{ "off", 0, BOND_VALFLAG_DEFAULT},
+	{ "on",	 1, 0},
+	{ NULL,  -1, 0}
+};
+
 static const struct bond_option bond_opts[BOND_OPT_LAST] = {
 	[BOND_OPT_MODE] = {
 		.id = BOND_OPT_MODE,
@@ -513,6 +521,14 @@ static const struct bond_option bond_opts[BOND_OPT_LAST] = {
 		.flags = BOND_OPTFLAG_IFDOWN,
 		.values = bond_coupled_control_tbl,
 		.set = bond_option_coupled_control_set,
+	},
+	[BOND_OPT_BROADCAST_NEIGH] = {
+		.id = BOND_OPT_BROADCAST_NEIGH,
+		.name = "broadcast_neighbor",
+		.desc = "Broadcast neighbor packets to all slaves",
+		.unsuppmodes = BOND_MODE_ALL_EX(BIT(BOND_MODE_8023AD)),
+		.values = bond_broadcast_neigh_tbl,
+		.set = bond_option_broadcast_neigh_set,
 	}
 };
 
@@ -1840,3 +1856,22 @@ static int bond_option_coupled_control_set(struct bonding *bond,
 	bond->params.coupled_control = newval->value;
 	return 0;
 }
+
+static int bond_option_broadcast_neigh_set(struct bonding *bond,
+					   const struct bond_opt_value *newval)
+{
+	if (bond->params.broadcast_neighbor == newval->value)
+		return 0;
+
+	bond->params.broadcast_neighbor = newval->value;
+	if (bond->dev->flags & IFF_UP) {
+		if (bond->params.broadcast_neighbor)
+			static_branch_inc(&bond_bcast_neigh_enabled);
+		else
+			static_branch_dec(&bond_bcast_neigh_enabled);
+	}
+
+	netdev_dbg(bond->dev, "Setting broadcast_neighbor to %s (%llu)\n",
+		   newval->string, newval->value);
+	return 0;
+}
diff --git a/include/net/bond_options.h b/include/net/bond_options.h
index 18687ccf0638..022b122a9fb6 100644
--- a/include/net/bond_options.h
+++ b/include/net/bond_options.h
@@ -77,6 +77,7 @@ enum {
 	BOND_OPT_NS_TARGETS,
 	BOND_OPT_PRIO,
 	BOND_OPT_COUPLED_CONTROL,
+	BOND_OPT_BROADCAST_NEIGH,
 	BOND_OPT_LAST
 };
 
diff --git a/include/net/bonding.h b/include/net/bonding.h
index 95f67b308c19..e06f0d63b2c1 100644
--- a/include/net/bonding.h
+++ b/include/net/bonding.h
@@ -115,6 +115,8 @@ static inline int is_netpoll_tx_blocked(struct net_device *dev)
 #define is_netpoll_tx_blocked(dev) (0)
 #endif
 
+DECLARE_STATIC_KEY_FALSE(bond_bcast_neigh_enabled);
+
 struct bond_params {
 	int mode;
 	int xmit_policy;
@@ -149,6 +151,7 @@ struct bond_params {
 	struct in6_addr ns_targets[BOND_MAX_NS_TARGETS];
 #endif
 	int coupled_control;
+	int broadcast_neighbor;
 
 	/* 2 bytes of padding : see ether_addr_equal_64bits() */
 	u8 ad_actor_system[ETH_ALEN + 2];
-- 
2.34.1

Re: [PATCH net-next v4 1/4] net: bonding: add broadcast_neighbor option for 802.3ad

[Nikolay Aleksandrov]

On 5/14/25 12:25, Tonghao Zhang wrote:
> Stacking technology is a type of technology used to expand ports on
> Ethernet switches. It is widely used as a common access method in
> large-scale Internet data center architectures. Years of practice
> have proved that stacking technology has advantages and disadvantages
> in high-reliability network architecture scenarios. For instance,
> in stacking networking arch, conventional switch system upgrades
> require multiple stacked devices to restart at the same time.
> Therefore, it is inevitable that the business will be interrupted
> for a while. It is for this reason that "no-stacking" in data centers
> has become a trend. Additionally, when the stacking link connecting
> the switches fails or is abnormal, the stack will split. Although it is
> not common, it still happens in actual operation. The problem is that
> after the split, it is equivalent to two switches with the same configuration
> appearing in the network, causing network configuration conflicts and
> ultimately interrupting the services carried by the stacking system.
> 
> To improve network stability, "non-stacking" solutions have been increasingly
> adopted, particularly by public cloud providers and tech companies
> like Alibaba, Tencent, and Didi. "non-stacking" is a method of mimicing switch
> stacking that convinces a LACP peer, bonding in this case, connected to a set of
> "non-stacked" switches that all of its ports are connected to a single
> switch (i.e., LACP aggregator), as if those switches were stacked. This
> enables the LACP peer's ports to aggregate together, and requires (a)
> special switch configuration, described in the linked article, and (b)
> modifications to the bonding 802.3ad (LACP) mode to send all ARP / ND
> packets across all ports of the active aggregator.
> 
>   -----------     -----------
>  |  switch1  |   |  switch2  |
>   -----------     -----------
>          ^           ^
>          |           |
>        -----------------
>       |   bond4 lacp    |
>        -----------------
>          |           |
>          | NIC1      | NIC2
>        -----------------
>       |     server      |
>        -----------------
> 
> - https://www.ruijie.com/fr-fr/support/tech-gallery/de-stack-data-center-network-architecture/
> 
> 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 |  6 ++++
>  drivers/net/bonding/bond_main.c      | 42 ++++++++++++++++++++++++++++
>  drivers/net/bonding/bond_options.c   | 35 +++++++++++++++++++++++
>  include/net/bond_options.h           |  1 +
>  include/net/bonding.h                |  3 ++
>  5 files changed, 87 insertions(+)
> 

Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>

Re: [PATCH net-next v4 1/4] net: bonding: add broadcast_neighbor option for 802.3ad

[Nikolay Aleksandrov]

On 5/14/25 12:36, Nikolay Aleksandrov wrote:
> On 5/14/25 12:25, Tonghao Zhang wrote:
>> Stacking technology is a type of technology used to expand ports on
>> Ethernet switches. It is widely used as a common access method in
>> large-scale Internet data center architectures. Years of practice
>> have proved that stacking technology has advantages and disadvantages
>> in high-reliability network architecture scenarios. For instance,
>> in stacking networking arch, conventional switch system upgrades
>> require multiple stacked devices to restart at the same time.
>> Therefore, it is inevitable that the business will be interrupted
>> for a while. It is for this reason that "no-stacking" in data centers
>> has become a trend. Additionally, when the stacking link connecting
>> the switches fails or is abnormal, the stack will split. Although it is
>> not common, it still happens in actual operation. The problem is that
>> after the split, it is equivalent to two switches with the same configuration
>> appearing in the network, causing network configuration conflicts and
>> ultimately interrupting the services carried by the stacking system.
>>
>> To improve network stability, "non-stacking" solutions have been increasingly
>> adopted, particularly by public cloud providers and tech companies
>> like Alibaba, Tencent, and Didi. "non-stacking" is a method of mimicing switch
>> stacking that convinces a LACP peer, bonding in this case, connected to a set of
>> "non-stacked" switches that all of its ports are connected to a single
>> switch (i.e., LACP aggregator), as if those switches were stacked. This
>> enables the LACP peer's ports to aggregate together, and requires (a)
>> special switch configuration, described in the linked article, and (b)
>> modifications to the bonding 802.3ad (LACP) mode to send all ARP / ND
>> packets across all ports of the active aggregator.
>>
>>   -----------     -----------
>>  |  switch1  |   |  switch2  |
>>   -----------     -----------
>>          ^           ^
>>          |           |
>>        -----------------
>>       |   bond4 lacp    |
>>        -----------------
>>          |           |
>>          | NIC1      | NIC2
>>        -----------------
>>       |     server      |
>>        -----------------
>>
>> - https://www.ruijie.com/fr-fr/support/tech-gallery/de-stack-data-center-network-architecture/
>>
>> 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 |  6 ++++
>>  drivers/net/bonding/bond_main.c      | 42 ++++++++++++++++++++++++++++
>>  drivers/net/bonding/bond_options.c   | 35 +++++++++++++++++++++++
>>  include/net/bond_options.h           |  1 +
>>  include/net/bonding.h                |  3 ++
>>  5 files changed, 87 insertions(+)
>>
> 
> Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
> 

Just in case anyone misses it - Jay has a few comments sent to v3 of this set:
https://lore.kernel.org/netdev/1338977.1747215491@vermin/T/#m695fa7cc6b4bf637391427bea8ad268ca7034709

It seems there will have to be another version, if you change the code please
don't add my reviewed-by tags to the changed patches because I'll have to
review them again.

Cheers,
 Nik

[PATCH net-next v4 2/4] net: bonding: add broadcast_neighbor netlink option

[Tonghao Zhang]

User can config or display the bonding broadcast_neighbor option via
iproute2/netlink.

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>
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>
---
 drivers/net/bonding/bond_netlink.c | 16 ++++++++++++++++
 include/uapi/linux/if_link.h       |  1 +
 2 files changed, 17 insertions(+)

diff --git a/drivers/net/bonding/bond_netlink.c b/drivers/net/bonding/bond_netlink.c
index ac5e402c34bc..57fff2421f1b 100644
--- a/drivers/net/bonding/bond_netlink.c
+++ b/drivers/net/bonding/bond_netlink.c
@@ -124,6 +124,7 @@ static const struct nla_policy bond_policy[IFLA_BOND_MAX + 1] = {
 	[IFLA_BOND_MISSED_MAX]		= { .type = NLA_U8 },
 	[IFLA_BOND_NS_IP6_TARGET]	= { .type = NLA_NESTED },
 	[IFLA_BOND_COUPLED_CONTROL]	= { .type = NLA_U8 },
+	[IFLA_BOND_BROADCAST_NEIGH]	= { .type = NLA_U8 },
 };
 
 static const struct nla_policy bond_slave_policy[IFLA_BOND_SLAVE_MAX + 1] = {
@@ -561,6 +562,16 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[],
 			return err;
 	}
 
+	if (data[IFLA_BOND_BROADCAST_NEIGH]) {
+		int broadcast_neigh = nla_get_u8(data[IFLA_BOND_BROADCAST_NEIGH]);
+
+		bond_opt_initval(&newval, broadcast_neigh);
+		err = __bond_opt_set(bond, BOND_OPT_BROADCAST_NEIGH, &newval,
+				     data[IFLA_BOND_BROADCAST_NEIGH], extack);
+		if (err)
+			return err;
+	}
+
 	return 0;
 }
 
@@ -630,6 +641,7 @@ static size_t bond_get_size(const struct net_device *bond_dev)
 		nla_total_size(sizeof(struct nlattr)) +
 		nla_total_size(sizeof(struct in6_addr)) * BOND_MAX_NS_TARGETS +
 		nla_total_size(sizeof(u8)) +	/* IFLA_BOND_COUPLED_CONTROL */
+		nla_total_size(sizeof(u8)) +	/* IFLA_BOND_BROADCAST_NEIGH */
 		0;
 }
 
@@ -793,6 +805,10 @@ static int bond_fill_info(struct sk_buff *skb,
 		       bond->params.coupled_control))
 		goto nla_put_failure;
 
+	if (nla_put_u8(skb, IFLA_BOND_BROADCAST_NEIGH,
+		       bond->params.broadcast_neighbor))
+		goto nla_put_failure;
+
 	if (BOND_MODE(bond) == BOND_MODE_8023AD) {
 		struct ad_info info;
 
diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h
index 3ad2d5d98034..53b2f6ebda8b 100644
--- a/include/uapi/linux/if_link.h
+++ b/include/uapi/linux/if_link.h
@@ -1534,6 +1534,7 @@ enum {
 	IFLA_BOND_MISSED_MAX,
 	IFLA_BOND_NS_IP6_TARGET,
 	IFLA_BOND_COUPLED_CONTROL,
+	IFLA_BOND_BROADCAST_NEIGH,
 	__IFLA_BOND_MAX,
 };
 
-- 
2.34.1

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

[Tonghao Zhang]

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

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

[Nikolay Aleksandrov]

On 5/14/25 12:25, Tonghao Zhang wrote:
> 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(-)
> 

rtnl is a bit heavy for updating a single variable, IMO
you should've refactored the code to protect it in a different way
(e.g. mode_lock or some other lighter type of sync primitive).

Anyway the patch does look good,
Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>

[PATCH net-next v4 4/4] net: bonding: add tracepoint for 802.3ad

[Tonghao Zhang]

Users can monitor NIC link status changes through netlink. However, LACP
protocol failures may occur despite operational physical links. There is
no way to detect LACP state changes. This patch adds tracepoint at LACP state
transition.

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>
---
 drivers/net/bonding/bond_3ad.c |  6 ++++++
 include/trace/events/bonding.h | 37 ++++++++++++++++++++++++++++++++++
 2 files changed, 43 insertions(+)
 create mode 100644 include/trace/events/bonding.h

diff --git a/drivers/net/bonding/bond_3ad.c b/drivers/net/bonding/bond_3ad.c
index d1c2d416ac87..55703230ab29 100644
--- a/drivers/net/bonding/bond_3ad.c
+++ b/drivers/net/bonding/bond_3ad.c
@@ -16,6 +16,9 @@
 #include <net/bond_3ad.h>
 #include <net/netlink.h>
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/bonding.h>
+
 /* General definitions */
 #define AD_SHORT_TIMEOUT           1
 #define AD_LONG_TIMEOUT            0
@@ -1146,6 +1149,9 @@ static void ad_mux_machine(struct port *port, bool *update_slave_arr)
 			  port->actor_port_number,
 			  last_state,
 			  port->sm_mux_state);
+
+		trace_3ad_mux_state(port->slave->dev, last_state, port->sm_mux_state);
+
 		switch (port->sm_mux_state) {
 		case AD_MUX_DETACHED:
 			port->actor_oper_port_state &= ~LACP_STATE_SYNCHRONIZATION;
diff --git a/include/trace/events/bonding.h b/include/trace/events/bonding.h
new file mode 100644
index 000000000000..1ee4b07d912a
--- /dev/null
+++ b/include/trace/events/bonding.h
@@ -0,0 +1,37 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#if !defined(_TRACE_BONDING_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_BONDING_H
+
+#include <linux/netdevice.h>
+#include <linux/tracepoint.h>
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM bonding
+
+TRACE_EVENT(3ad_mux_state,
+	TP_PROTO(struct net_device *dev, u32 last_state, u32 curr_state),
+	TP_ARGS(dev, last_state, curr_state),
+
+	TP_STRUCT__entry(
+		__field(int, ifindex)
+		__string(dev_name, dev->name)
+		__field(u32, last_state)
+		__field(u32, curr_state)
+	),
+
+	TP_fast_assign(
+		__entry->ifindex = dev->ifindex;
+		__assign_str(dev_name);
+		__entry->last_state = last_state;
+		__entry->curr_state = curr_state;
+	),
+
+	TP_printk("ifindex %d dev %s last_state 0x%x curr_state 0x%x",
+		  __entry->ifindex, __get_str(dev_name),
+		  __entry->last_state, __entry->curr_state)
+);
+
+#endif /* _TRACE_BONDING_H */
+
+#include <trace/define_trace.h>
-- 
2.34.1

Re: [PATCH net-next v4 4/4] net: bonding: add tracepoint for 802.3ad

[Nikolay Aleksandrov]

On 5/14/25 12:25, Tonghao Zhang wrote:
> Users can monitor NIC link status changes through netlink. However, LACP
> protocol failures may occur despite operational physical links. There is
> no way to detect LACP state changes. This patch adds tracepoint at LACP state
> transition.
> 
> 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>
> ---
>  drivers/net/bonding/bond_3ad.c |  6 ++++++
>  include/trace/events/bonding.h | 37 ++++++++++++++++++++++++++++++++++
>  2 files changed, 43 insertions(+)
>  create mode 100644 include/trace/events/bonding.h
> 

Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org>

Re: [PATCH net-next v4 4/4] net: bonding: add tracepoint for 802.3ad

[Jay Vosburgh]

Tonghao Zhang <tonghao@bamaicloud.com> wrote:

>Users can monitor NIC link status changes through netlink. However, LACP
>protocol failures may occur despite operational physical links. There is
>no way to detect LACP state changes. This patch adds tracepoint at LACP state
>transition.
>
>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>
>---
> drivers/net/bonding/bond_3ad.c |  6 ++++++
> include/trace/events/bonding.h | 37 ++++++++++++++++++++++++++++++++++
> 2 files changed, 43 insertions(+)
> create mode 100644 include/trace/events/bonding.h
>
>diff --git a/drivers/net/bonding/bond_3ad.c b/drivers/net/bonding/bond_3ad.c
>index d1c2d416ac87..55703230ab29 100644
>--- a/drivers/net/bonding/bond_3ad.c
>+++ b/drivers/net/bonding/bond_3ad.c
>@@ -16,6 +16,9 @@
> #include <net/bond_3ad.h>
> #include <net/netlink.h>
> 
>+#define CREATE_TRACE_POINTS
>+#include <trace/events/bonding.h>
>+
> /* General definitions */
> #define AD_SHORT_TIMEOUT           1
> #define AD_LONG_TIMEOUT            0
>@@ -1146,6 +1149,9 @@ static void ad_mux_machine(struct port *port, bool *update_slave_arr)
> 			  port->actor_port_number,
> 			  last_state,
> 			  port->sm_mux_state);
>+
>+		trace_3ad_mux_state(port->slave->dev, last_state, port->sm_mux_state);
>+

	First, wasn't someone trying to integrate the LACP state changes
into the usual "ip monitor" netlink notifications?  What happened to
that?

	Second, the "3ad" nomenclature is obsolete; it refers to the
original IEEE 802.3ad standard, which was replaced by 802.1AX in 2008.
Most of the time, though, folks refer to this as "LACP."  Anyway, my
point here is that the name, assuming we go with a tracepoint, should
have "lacp" in it instead of "3ad."

	-J

> 		switch (port->sm_mux_state) {
> 		case AD_MUX_DETACHED:
> 			port->actor_oper_port_state &= ~LACP_STATE_SYNCHRONIZATION;
>diff --git a/include/trace/events/bonding.h b/include/trace/events/bonding.h
>new file mode 100644
>index 000000000000..1ee4b07d912a
>--- /dev/null
>+++ b/include/trace/events/bonding.h
>@@ -0,0 +1,37 @@
>+/* SPDX-License-Identifier: GPL-2.0 */
>+
>+#if !defined(_TRACE_BONDING_H) || defined(TRACE_HEADER_MULTI_READ)
>+#define _TRACE_BONDING_H
>+
>+#include <linux/netdevice.h>
>+#include <linux/tracepoint.h>
>+
>+#undef TRACE_SYSTEM
>+#define TRACE_SYSTEM bonding
>+
>+TRACE_EVENT(3ad_mux_state,
>+	TP_PROTO(struct net_device *dev, u32 last_state, u32 curr_state),
>+	TP_ARGS(dev, last_state, curr_state),
>+
>+	TP_STRUCT__entry(
>+		__field(int, ifindex)
>+		__string(dev_name, dev->name)
>+		__field(u32, last_state)
>+		__field(u32, curr_state)
>+	),
>+
>+	TP_fast_assign(
>+		__entry->ifindex = dev->ifindex;
>+		__assign_str(dev_name);
>+		__entry->last_state = last_state;
>+		__entry->curr_state = curr_state;
>+	),
>+
>+	TP_printk("ifindex %d dev %s last_state 0x%x curr_state 0x%x",
>+		  __entry->ifindex, __get_str(dev_name),
>+		  __entry->last_state, __entry->curr_state)
>+);
>+
>+#endif /* _TRACE_BONDING_H */
>+
>+#include <trace/define_trace.h>
>-- 
>2.34.1
>
>

---
	-Jay Vosburgh, jv@jvosburgh.net