bonding: fix macvlan over alb bond support

The commit 14af996 ("bonding: Support macvlans on top of tlb/rlb mode
bonds") aims to enable the use of macvlans on top of rlb bond mode. However,
the current rlb bond mode only handles ARP packets to update remote neighbor
entries. This causes an issue when a macvlan is on top of the bond, and
remote devices send packets to the macvlan using the bond's MAC address
as the destination. After delivering the packets to the macvlan, the macvlan
will rejects them as the MAC address is incorrect. Consequently, this commit
makes macvlan over bond non-functional.

To address this problem, one potential solution is to check for the presence
of a macvlan port on the bond device using netif_is_macvlan_port(bond->dev)
and return NULL in the rlb_arp_xmit() function. However, this approach
doesn't fully resolve the situation when a VLAN exists between the bond and
macvlan.

So let's just do a partial revert for commit 14af996 in rlb_arp_xmit().
As the comment said, Don't modify or load balance ARPs that do not originate
locally.

Fixes: 14af996 ("bonding: Support macvlans on top of tlb/rlb mode bonds")
Reported-by: susan.zheng@veritas.com
Closes: https://bugzilla.redhat.com/show_bug.cgi?id=2117816
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Acked-by: Jay Vosburgh <jay.vosburgh@canonical.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

Author: liuhangbin

drivers/net/bonding/bond_alb.c

@@ -660,10 +660,10 @@ static struct slave *rlb_arp_xmit(struct sk_buff *skb, struct bonding *bond)
 		return NULL;
 	arp = (struct arp_pkt *)skb_network_header(skb);
 
-	/* Don't modify or load balance ARPs that do not originate locally
-	 * (e.g.,arrive via a bridge).
+	/* Don't modify or load balance ARPs that do not originate
+	 * from the bond itself or a VLAN directly above the bond.
 	 */
-	if (!bond_slave_has_mac_rx(bond, arp->mac_src))
+	if (!bond_slave_has_mac_rcu(bond, arp->mac_src))
 		return NULL;
 
 	dev = ip_dev_find(dev_net(bond->dev), arp->ip_src);

include/net/bonding.h

@@ -722,23 +722,14 @@ static inline struct slave *bond_slave_has_mac(struct bonding *bond,
 }
 
 /* Caller must hold rcu_read_lock() for read */
-static inline bool bond_slave_has_mac_rx(struct bonding *bond, const u8 *mac)
+static inline bool bond_slave_has_mac_rcu(struct bonding *bond, const u8 *mac)
 {
 	struct list_head *iter;
 	struct slave *tmp;
-	struct netdev_hw_addr *ha;
 
 	bond_for_each_slave_rcu(bond, tmp, iter)
 		if (ether_addr_equal_64bits(mac, tmp->dev->dev_addr))
 			return true;
-
-	if (netdev_uc_empty(bond->dev))
-		return false;
-
-	netdev_for_each_uc_addr(ha, bond->dev)
-		if (ether_addr_equal_64bits(mac, ha->addr))
-			return true;
-
 	return false;
 }