[PATCH net] Bonding: update bond device XFRM features based on current active slave

[Hangbin Liu <liuhangbin@gmail.com>]

XFRM offload is supported in active-backup mode. However, if the current
active slave does not support it, we should disable it on bond device.
Otherwise, ESP traffic may fail due to the downlink not supporting the
feature.

Reproducer:
  # ip link add bond0 type bond
  # ip link add type veth
  # ip link set bond0 type bond mode 1 miimon 100
  # ip link set veth0 master bond0
  # ethtool -k veth0 | grep esp
  tx-esp-segmentation: off [fixed]
  esp-hw-offload: off [fixed]
  esp-tx-csum-hw-offload: off [fixed]
  # ethtool -k bond0 | grep esp
  tx-esp-segmentation: on
  esp-hw-offload: on
  esp-tx-csum-hw-offload: on

After fix:
  # ethtool -k bond0 | grep esp
  tx-esp-segmentation: off [requested on]
  esp-hw-offload: off [requested on]
  esp-tx-csum-hw-offload: off [requested on]

Fixes: a3b658cfb664 ("bonding: allow xfrm offload setup post-module-load")
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
---
 drivers/net/bonding/bond_main.c | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index b560644ee1b1..33f7fde15c65 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1353,6 +1353,10 @@ void bond_change_active_slave(struct bonding *bond, struct slave *new_active)
 				call_netdevice_notifiers(NETDEV_NOTIFY_PEERS,
 							 bond->dev);
 			}
+
+#ifdef CONFIG_XFRM_OFFLOAD
+			netdev_update_features(bond->dev);
+#endif /* CONFIG_XFRM_OFFLOAD */
 		}
 	}
 
@@ -1524,6 +1528,11 @@ static netdev_features_t bond_fix_features(struct net_device *dev,
 		features = netdev_increment_features(features,
 						     slave->dev->features,
 						     mask);
+#ifdef CONFIG_XFRM_OFFLOAD
+		if (BOND_MODE(bond) == BOND_MODE_ACTIVEBACKUP &&
+		    slave == rtnl_dereference(bond->curr_active_slave))
+			features &= slave->dev->features & BOND_XFRM_FEATURES;
+#endif /* CONFIG_XFRM_OFFLOAD */
 	}
 	features = netdev_add_tso_features(features, mask);
 
-- 
2.39.3 (Apple Git-146)