bonding: make bond_arp_send_all use upper device list

Currently, bond_arp_send_all() is aware only of vlans, which breaks
configurations like bond <- bridge (or any other 'upper' device) with IP
(which is quite a common scenario for virt setups).

To fix this we convert the bond_arp_send_all() to first verify if the rt
device is the bond itself, and if not - to go through its list of upper
vlans and their respectiv upper devices (if the vlan's upper device matches
- tag the packet), if still not found - go through all of our upper list
devices to see if any of them match the route device for the target. If the
match is a vlan device - we also save its vlan_id and tag it in
bond_arp_send().

Also, clean the function a bit to be more readable.

CC: Vlad Yasevich <vyasevic@redhat.com>
CC: Jay Vosburgh <fubar@us.ibm.com>
CC: Andy Gospodarek <andy@greyhouse.net>
Signed-off-by: Veaceslav Falico <vfalico@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/bonding/bond_main.c

@@ -2444,30 +2444,16 @@ static void bond_arp_send(struct net_device *slave_dev, int arp_op, __be32 dest_
 
 static void bond_arp_send_all(struct bonding *bond, struct slave *slave)
 {
-	int i, vlan_id;
-	__be32 *targets = bond->params.arp_targets;
-	struct vlan_entry *vlan;
-	struct net_device *vlan_dev = NULL;
+	struct net_device *upper, *vlan_upper;
+	struct list_head *iter, *vlan_iter;
 	struct rtable *rt;
+	__be32 *targets = bond->params.arp_targets, addr;
+	int i, vlan_id;
 
-	for (i = 0; (i < BOND_MAX_ARP_TARGETS); i++) {
-		__be32 addr;
-		if (!targets[i])
-			break;
+	for (i = 0; i < BOND_MAX_ARP_TARGETS && targets[i]; i++) {
 		pr_debug("basa: target %pI4\n", &targets[i]);
-		if (!bond_vlan_used(bond)) {
-			pr_debug("basa: empty vlan: arp_send\n");
-			addr = bond_confirm_addr(bond->dev, targets[i], 0);
-			bond_arp_send(slave->dev, ARPOP_REQUEST, targets[i],
-				      addr, 0);
-			continue;
-		}
 
-		/*
-		 * If VLANs are configured, we do a route lookup to
-		 * determine which VLAN interface would be used, so we
-		 * can tag the ARP with the proper VLAN tag.
-		 */
+		/* Find out through which dev should the packet go */
 		rt = ip_route_output(dev_net(bond->dev), targets[i], 0,
 				     RTO_ONLINK, 0);
 		if (IS_ERR(rt)) {
@@ -2478,47 +2464,61 @@ static void bond_arp_send_all(struct bonding *bond, struct slave *slave)
 			continue;
 		}
 
-		/*
-		 * This target is not on a VLAN
-		 */
-		if (rt->dst.dev == bond->dev) {
-			ip_rt_put(rt);
-			pr_debug("basa: rtdev == bond->dev: arp_send\n");
-			addr = bond_confirm_addr(bond->dev, targets[i], 0);
-			bond_arp_send(slave->dev, ARPOP_REQUEST, targets[i],
-				      addr, 0);
-			continue;
-		}
-
 		vlan_id = 0;
-		list_for_each_entry(vlan, &bond->vlan_list, vlan_list) {
-			rcu_read_lock();
-			vlan_dev = __vlan_find_dev_deep(bond->dev,
-							htons(ETH_P_8021Q),
-							vlan->vlan_id);
-			rcu_read_unlock();
-			if (vlan_dev == rt->dst.dev) {
-				vlan_id = vlan->vlan_id;
-				pr_debug("basa: vlan match on %s %d\n",
-				       vlan_dev->name, vlan_id);
-				break;
+
+		/* bond device itself */
+		if (rt->dst.dev == bond->dev)
+			goto found;
+
+		rcu_read_lock();
+		/* first we search only for vlan devices. for every vlan
+		 * found we verify its upper dev list, searching for the
+		 * rt->dst.dev. If found we save the tag of the vlan and
+		 * proceed to send the packet.
+		 *
+		 * TODO: QinQ?
+		 */
+		netdev_for_each_upper_dev_rcu(bond->dev, vlan_upper, vlan_iter) {
+			if (!is_vlan_dev(vlan_upper))
+				continue;
+			netdev_for_each_upper_dev_rcu(vlan_upper, upper, iter) {
+				if (upper == rt->dst.dev) {
+					vlan_id = vlan_dev_vlan_id(vlan_upper);
+					rcu_read_unlock();
+					goto found;
+				}
 			}
 		}
 
-		if (vlan_id && vlan_dev) {
-			ip_rt_put(rt);
-			addr = bond_confirm_addr(vlan_dev, targets[i], 0);
-			bond_arp_send(slave->dev, ARPOP_REQUEST, targets[i],
-				      addr, vlan_id);
-			continue;
-		}
+		/* if the device we're looking for is not on top of any of
+		 * our upper vlans, then just search for any dev that
+		 * matches, and in case it's a vlan - save the id
+		 */
+		netdev_for_each_upper_dev_rcu(bond->dev, upper, iter) {
+			if (upper == rt->dst.dev) {
+				/* if it's a vlan - get its VID */
+				if (is_vlan_dev(upper))
+					vlan_id = vlan_dev_vlan_id(upper);
 
-		if (net_ratelimit()) {
+				rcu_read_unlock();
+				goto found;
+			}
+		}
+		rcu_read_unlock();
+
+		/* Not our device - skip */
+		if (net_ratelimit())
 			pr_warning("%s: no path to arp_ip_target %pI4 via rt.dev %s\n",
 				   bond->dev->name, &targets[i],
 				   rt->dst.dev ? rt->dst.dev->name : "NULL");
-		}
 		ip_rt_put(rt);
+		continue;
+
+found:
+		addr = bond_confirm_addr(rt->dst.dev, targets[i], 0);
+		ip_rt_put(rt);
+		bond_arp_send(slave->dev, ARPOP_REQUEST, targets[i],
+			      addr, vlan_id);
 	}
 }