bonding: support QinQ for bond arp interval

The bond send arp request to indicate that the slave is active, and if the bond dev
is a vlan dev, it will set the vlan tag in skb to notice the vlan group, but the
bond could only send a skb with 802.1q proto, not support for QinQ.

So add outer tag for lower vlan tag and inner tag for upper vlan tag to support QinQ,
The new skb will be consist of two vlan tag just like this:

dst mac | src mac | outer vlan tag | inner vlan tag | data | .....

If We don't need QinQ, the inner vlan tag could be set to 0 and use outer vlan tag
 as a normal vlan group.

Using "ip link" to configure the bond for QinQ and add test log:

ip link add link bond0  bond0.20 type vlan proto 802.1ad id 20
ip link add link bond0.20  bond0.20.200 type vlan proto 802.1q id 200

ifconfig bond0.20 11.11.20.36/24
ifconfig bond0.20.200 11.11.200.36/24

echo +11.11.200.37 > /sys/class/net/bond0/bonding/arp_ip_target

90:e2:ba:07:4a:5c (oui Unknown) > Broadcast, ethertype 802.1Q-QinQ (0x88a8),length 50: vlan 20, p 0,ethertype 802.1Q, vlan 200, p 0, ethertype ARP, Ethernet (len 6), IPv4 (len 4), Request who-has 11.11.200.37 tell 11.11.200.36, length 28

90:e2:ba:06:f9:86 (oui Unknown) > 90:e2:ba:07:4a:5c (oui Unknown), ethertype 802.1Q-QinQ (0x88a8), length 50: vlan 20, p 0, ethertype 802.1Q, vlan 200, p 0, ethertype ARP, Ethernet (len 6), IPv4 (len 4), Reply 11.11.200.37 is-at 90:e2:ba:06:f9:86 (oui Unknown), length 28

v1->v2: remove the comment "TODO: QinQ?".

Cc: Jay Vosburgh <fubar@us.ibm.com>
Cc: Veaceslav Falico <vfalico@redhat.com>
Cc: Andy Gospodarek <andy@greyhouse.net>
Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/bonding/bond_main.c

@@ -2124,12 +2124,15 @@ static bool bond_has_this_ip(struct bonding *bond, __be32 ip)
  * switches in VLAN mode (especially if ports are configured as
  * "native" to a VLAN) might not pass non-tagged frames.
  */
-static void bond_arp_send(struct net_device *slave_dev, int arp_op, __be32 dest_ip, __be32 src_ip, unsigned short vlan_id)
+static void bond_arp_send(struct net_device *slave_dev, int arp_op,
+			  __be32 dest_ip, __be32 src_ip,
+			  struct bond_vlan_tag *inner,
+			  struct bond_vlan_tag *outer)
 {
 	struct sk_buff *skb;
 
-	pr_debug("arp %d on slave %s: dst %pI4 src %pI4 vid %d\n",
-		 arp_op, slave_dev->name, &dest_ip, &src_ip, vlan_id);
+	pr_debug("arp %d on slave %s: dst %pI4 src %pI4\n",
+		 arp_op, slave_dev->name, &dest_ip, &src_ip);
 
 	skb = arp_create(arp_op, ETH_P_ARP, dest_ip, slave_dev, src_ip,
 			 NULL, slave_dev->dev_addr, NULL);
@@ -2138,10 +2141,22 @@ static void bond_arp_send(struct net_device *slave_dev, int arp_op, __be32 dest_
 		pr_err("ARP packet allocation failed\n");
 		return;
 	}
-	if (vlan_id) {
-		skb = vlan_put_tag(skb, htons(ETH_P_8021Q), vlan_id);
+	if (outer->vlan_id) {
+		if (inner->vlan_id) {
+			pr_debug("inner tag: proto %X vid %X\n",
+				 ntohs(inner->vlan_proto), inner->vlan_id);
+			skb = __vlan_put_tag(skb, inner->vlan_proto, inner->vlan_id);
+			if (!skb) {
+				pr_err("failed to insert inner VLAN tag\n");
+				return;
+			}
+		}
+
+		pr_debug("outer reg: proto %X vid %X\n",
+			 ntohs(outer->vlan_proto), outer->vlan_id);
+		skb = vlan_put_tag(skb, outer->vlan_proto, outer->vlan_id);
 		if (!skb) {
-			pr_err("failed to insert VLAN tag\n");
+			pr_err("failed to insert outer VLAN tag\n");
 			return;
 		}
 	}
@@ -2154,11 +2169,16 @@ static void bond_arp_send_all(struct bonding *bond, struct slave *slave)
 	struct net_device *upper, *vlan_upper;
 	struct list_head *iter, *vlan_iter;
 	struct rtable *rt;
+	struct bond_vlan_tag inner, outer;
 	__be32 *targets = bond->params.arp_targets, addr;
-	int i, vlan_id;
+	int i;
 
 	for (i = 0; i < BOND_MAX_ARP_TARGETS && targets[i]; i++) {
 		pr_debug("basa: target %pI4\n", &targets[i]);
+		inner.vlan_proto = 0;
+		inner.vlan_id = 0;
+		outer.vlan_proto = 0;
+		outer.vlan_id = 0;
 
 		/* Find out through which dev should the packet go */
 		rt = ip_route_output(dev_net(bond->dev), targets[i], 0,
@@ -2170,12 +2190,10 @@ static void bond_arp_send_all(struct bonding *bond, struct slave *slave)
 			if (bond->params.arp_validate && net_ratelimit())
 				pr_warn("%s: no route to arp_ip_target %pI4 and arp_validate is set\n",
 					bond->dev->name, &targets[i]);
-			bond_arp_send(slave->dev, ARPOP_REQUEST, targets[i], 0, 0);
+			bond_arp_send(slave->dev, ARPOP_REQUEST, targets[i], 0, &inner, &outer);
 			continue;
 		}
 
-		vlan_id = 0;
-
 		/* bond device itself */
 		if (rt->dst.dev == bond->dev)
 			goto found;
@@ -2185,17 +2203,30 @@ static void bond_arp_send_all(struct bonding *bond, struct slave *slave)
 		 * 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_all_upper_dev_rcu(bond->dev, vlan_upper,
 						  vlan_iter) {
 			if (!is_vlan_dev(vlan_upper))
 				continue;
+
+			if (vlan_upper == rt->dst.dev) {
+				outer.vlan_proto = vlan_dev_vlan_proto(vlan_upper);
+				outer.vlan_id = vlan_dev_vlan_id(vlan_upper);
+				rcu_read_unlock();
+				goto found;
+			}
 			netdev_for_each_all_upper_dev_rcu(vlan_upper, upper,
 							  iter) {
 				if (upper == rt->dst.dev) {
-					vlan_id = vlan_dev_vlan_id(vlan_upper);
+					/* If the upper dev is a vlan dev too,
+					 *  set the vlan tag to inner tag.
+					 */
+					if (is_vlan_dev(upper)) {
+						inner.vlan_proto = vlan_dev_vlan_proto(upper);
+						inner.vlan_id = vlan_dev_vlan_id(upper);
+					}
+					outer.vlan_proto = vlan_dev_vlan_proto(vlan_upper);
+					outer.vlan_id = vlan_dev_vlan_id(vlan_upper);
 					rcu_read_unlock();
 					goto found;
 				}
@@ -2208,10 +2239,6 @@ static void bond_arp_send_all(struct bonding *bond, struct slave *slave)
 		 */
 		netdev_for_each_all_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);
-
 				rcu_read_unlock();
 				goto found;
 			}
@@ -2230,7 +2257,7 @@ static void bond_arp_send_all(struct bonding *bond, struct slave *slave)
 		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);
+			      addr, &inner, &outer);
 	}
 }
 

drivers/net/bonding/bonding.h

@@ -266,6 +266,11 @@ struct bonding {
 #define bond_slave_get_rtnl(dev) \
 	((struct slave *) rtnl_dereference(dev->rx_handler_data))
 
+struct bond_vlan_tag {
+	__be16		vlan_proto;
+	unsigned short	vlan_id;
+};
+
 /**
  * Returns NULL if the net_device does not belong to any of the bond's slaves
  *