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Fri, 17 Apr 2026 07:05:07 -0700 (PDT) Received: from smtpservice.6wind.com ([185.13.181.2]) by smtp-relay.gmail.com with ESMTP id 2adb3069b0e04-5a4185b10c2sm114515e87.1.2026.04.17.07.05.07; Fri, 17 Apr 2026 07:05:07 -0700 (PDT) X-Relaying-Domain: 6wind.com Received: from stryper.dev.6wind.com (stryper.dev.6wind.com [10.17.2.5]) by smtpservice.6wind.com (Postfix) with ESMTP id 250BB1364E; Fri, 17 Apr 2026 16:05:07 +0200 (CEST) From: Louis Scalbert To: netdev@vger.kernel.org Cc: stephen@networkplumber.org, andrew+netdev@lunn.ch, jv@jvosburgh.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, fbl@redhat.com, andy@greyhouse.net, shemminger@vyatta.com, maheshb@google.com, Louis Scalbert Subject: [PATCH net v4 1/4] bonding: 3ad: add lacp_strict configuration knob Date: Fri, 17 Apr 2026 16:05:02 +0200 Message-Id: <20260417140505.3860237-2-louis.scalbert@6wind.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20260417140505.3860237-1-louis.scalbert@6wind.com> References: <20260417140505.3860237-1-louis.scalbert@6wind.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit When an 802.3ad (LACP) bonding interface has no slaves in the collecting/distributing state, the bonding master still reports carrier as up as long as at least 'min_links' slaves have carrier. In this situation, only one slave is effectively used for TX/RX, while traffic received on other slaves is dropped. Upper-layer daemons therefore consider the interface operational, even though traffic may be blackholed if the lack of LACP negotiation means the partner is not ready to deal with traffic. Introduce a configuration knob to control this behavior. It allows the bonding master to assert carrier only when at least 'min_links' slaves are in Collecting_Distributing state. The default mode preserves the existing behavior. This patch only introduces the knob; its behavior is implemented in the subsequent commit. Fixes: 655f8919d549 ("bonding: add min links parameter to 802.3ad") Signed-off-by: Louis Scalbert --- Documentation/networking/bonding.rst | 23 +++++++++++++++++++++++ drivers/net/bonding/bond_main.c | 1 + drivers/net/bonding/bond_netlink.c | 16 ++++++++++++++++ drivers/net/bonding/bond_options.c | 26 ++++++++++++++++++++++++++ include/net/bond_options.h | 1 + include/net/bonding.h | 1 + include/uapi/linux/if_link.h | 1 + 7 files changed, 69 insertions(+) diff --git a/Documentation/networking/bonding.rst b/Documentation/networking/bonding.rst index e700bf1d095c..33ca5afafdf6 100644 --- a/Documentation/networking/bonding.rst +++ b/Documentation/networking/bonding.rst @@ -619,6 +619,29 @@ min_links aggregator cannot be active without at least one available link, setting this option to 0 or to 1 has the exact same effect. +lacp_strict + + Specifies the fallback behavior of a bonding when LACP negotiation + fails on all slave links, i.e. when no slave is in the + Collecting_Distributing state, while at least `min_links` link still + reports carrier up. + + This option is only applicable to 802.3ad mode (mode 4). + + Valid values are: + + off or 0 + One interface of the bond is selected to be active, in order to + facilitate communication with peer devices that do not implement + LACP. + + on or 1 + Interfaces are only permitted to be made active if they have an + active LACP partner and have successfully reached + Collecting_Distributing state. + + The default value is 0 (off). + mode Specifies one of the bonding policies. The default is diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c index c7baa5c4bf40..b1a446630d1d 100644 --- a/drivers/net/bonding/bond_main.c +++ b/drivers/net/bonding/bond_main.c @@ -6438,6 +6438,7 @@ static int __init bond_check_params(struct bond_params *params) params->ad_user_port_key = ad_user_port_key; params->coupled_control = 1; params->broadcast_neighbor = 0; + params->lacp_strict = 0; if (packets_per_slave > 0) { params->reciprocal_packets_per_slave = reciprocal_value(packets_per_slave); diff --git a/drivers/net/bonding/bond_netlink.c b/drivers/net/bonding/bond_netlink.c index ea1a80e658ae..4b8207df4810 100644 --- a/drivers/net/bonding/bond_netlink.c +++ b/drivers/net/bonding/bond_netlink.c @@ -139,6 +139,7 @@ static const struct nla_policy bond_policy[IFLA_BOND_MAX + 1] = { [IFLA_BOND_NS_IP6_TARGET] = { .type = NLA_NESTED }, [IFLA_BOND_COUPLED_CONTROL] = { .type = NLA_U8 }, [IFLA_BOND_BROADCAST_NEIGH] = { .type = NLA_U8 }, + [IFLA_BOND_LACP_STRICT] = { .type = NLA_U8 }, }; static const struct nla_policy bond_slave_policy[IFLA_BOND_SLAVE_MAX + 1] = { @@ -595,6 +596,16 @@ static int bond_changelink(struct net_device *bond_dev, struct nlattr *tb[], return err; } + if (data[IFLA_BOND_LACP_STRICT]) { + int fallback_mode = nla_get_u8(data[IFLA_BOND_LACP_STRICT]); + + bond_opt_initval(&newval, fallback_mode); + err = __bond_opt_set(bond, BOND_OPT_LACP_STRICT, &newval, + data[IFLA_BOND_LACP_STRICT], extack); + if (err) + return err; + } + return 0; } @@ -667,6 +678,7 @@ static size_t bond_get_size(const struct net_device *bond_dev) 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 */ + nla_total_size(sizeof(u8)) + /* IFLA_BOND_LACP_STRICT */ 0; } @@ -834,6 +846,10 @@ static int bond_fill_info(struct sk_buff *skb, bond->params.broadcast_neighbor)) goto nla_put_failure; + if (nla_put_u8(skb, IFLA_BOND_LACP_STRICT, + bond->params.lacp_strict)) + goto nla_put_failure; + if (BOND_MODE(bond) == BOND_MODE_8023AD) { struct ad_info info; diff --git a/drivers/net/bonding/bond_options.c b/drivers/net/bonding/bond_options.c index 7380cc4ee75a..d358b831df77 100644 --- a/drivers/net/bonding/bond_options.c +++ b/drivers/net/bonding/bond_options.c @@ -68,6 +68,8 @@ static int bond_option_lacp_active_set(struct bonding *bond, const struct bond_opt_value *newval); static int bond_option_lacp_rate_set(struct bonding *bond, const struct bond_opt_value *newval); +static int bond_option_lacp_strict_set(struct bonding *bond, + const struct bond_opt_value *newval); static int bond_option_ad_select_set(struct bonding *bond, const struct bond_opt_value *newval); static int bond_option_queue_id_set(struct bonding *bond, @@ -162,6 +164,12 @@ static const struct bond_opt_value bond_lacp_rate_tbl[] = { { NULL, -1, 0}, }; +static const struct bond_opt_value bond_lacp_strict_tbl[] = { + { "off", 0, BOND_VALFLAG_DEFAULT}, + { "on", 1, 0}, + { NULL, -1, 0 } +}; + static const struct bond_opt_value bond_ad_select_tbl[] = { { "stable", BOND_AD_STABLE, BOND_VALFLAG_DEFAULT}, { "bandwidth", BOND_AD_BANDWIDTH, 0}, @@ -363,6 +371,14 @@ static const struct bond_option bond_opts[BOND_OPT_LAST] = { .values = bond_lacp_rate_tbl, .set = bond_option_lacp_rate_set }, + [BOND_OPT_LACP_STRICT] = { + .id = BOND_OPT_LACP_STRICT, + .name = "lacp_strict", + .desc = "Define the LACP fallback mode when no slaves have negotiated", + .unsuppmodes = BOND_MODE_ALL_EX(BIT(BOND_MODE_8023AD)), + .values = bond_lacp_strict_tbl, + .set = bond_option_lacp_strict_set + }, [BOND_OPT_MINLINKS] = { .id = BOND_OPT_MINLINKS, .name = "min_links", @@ -1684,6 +1700,16 @@ static int bond_option_lacp_rate_set(struct bonding *bond, return 0; } +static int bond_option_lacp_strict_set(struct bonding *bond, + const struct bond_opt_value *newval) +{ + netdev_dbg(bond->dev, "Setting LACP fallback to %s (%llu)\n", + newval->string, newval->value); + bond->params.lacp_strict = newval->value; + + return 0; +} + static int bond_option_ad_select_set(struct bonding *bond, const struct bond_opt_value *newval) { diff --git a/include/net/bond_options.h b/include/net/bond_options.h index e6eedf23aea1..52b966e92793 100644 --- a/include/net/bond_options.h +++ b/include/net/bond_options.h @@ -79,6 +79,7 @@ enum { BOND_OPT_COUPLED_CONTROL, BOND_OPT_BROADCAST_NEIGH, BOND_OPT_ACTOR_PORT_PRIO, + BOND_OPT_LACP_STRICT, BOND_OPT_LAST }; diff --git a/include/net/bonding.h b/include/net/bonding.h index edd1942dcd73..2c54a36a8477 100644 --- a/include/net/bonding.h +++ b/include/net/bonding.h @@ -129,6 +129,7 @@ struct bond_params { int peer_notif_delay; int lacp_active; int lacp_fast; + int lacp_strict; unsigned int min_links; int ad_select; char primary[IFNAMSIZ]; diff --git a/include/uapi/linux/if_link.h b/include/uapi/linux/if_link.h index 79ce4bc24cba..9ef5784e78e8 100644 --- a/include/uapi/linux/if_link.h +++ b/include/uapi/linux/if_link.h @@ -1584,6 +1584,7 @@ enum { IFLA_BOND_NS_IP6_TARGET, IFLA_BOND_COUPLED_CONTROL, IFLA_BOND_BROADCAST_NEIGH, + IFLA_BOND_LACP_STRICT, __IFLA_BOND_MAX, }; -- 2.39.2