bonding: make it possible to have unlimited nested upper vlans

Currently we're limited by a constant level of vlan nestings, and fail to
find anything beyound that level (currently 2).

To fix this - remove the limit of nestings when going through device tree,
and when the end device is found - allocate the needed amount of vlan tags
and return them, instead of found/not found.

CC: Jay Vosburgh <j.vosburgh@gmail.com>
CC: Andy Gospodarek <andy@greyhouse.net>
Signed-off-by: Veaceslav Falico <vfalico@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

3 files changed, 58 insertions, 39 deletions

diff --git a/drivers/net/bonding/bond_alb.c b/drivers/net/bonding/bond_alb.c
index d3c6801f101e..95dd1f58c260 100644
--- a/drivers/net/bonding/bond_alb.c
+++ b/drivers/net/bonding/bond_alb.c
@@ -1042,7 +1042,7 @@ static void alb_send_learning_packets(struct slave *slave, u8 mac_addr[],
         struct bonding *bond = bond_get_bond_by_slave(slave);
         struct net_device *upper;
         struct list_head *iter;
-        struct bond_vlan_tag tags[BOND_MAX_VLAN_ENCAP];
+        struct bond_vlan_tag *tags;
 
         /* send untagged */
         alb_send_lp_vid(slave, mac_addr, 0, 0);
@@ -1070,10 +1070,12 @@ static void alb_send_learning_packets(struct slave *slave, u8 mac_addr[],
                  * when strict_match is turned off.
                  */
                 if (netif_is_macvlan(upper) && !strict_match) {
-                        memset(tags, 0, sizeof(tags));
-                        bond_verify_device_path(bond->dev, upper, tags);
+                        tags = bond_verify_device_path(bond->dev, upper, 0);
+                        if (IS_ERR_OR_NULL(tags))
+                                BUG();
                         alb_send_lp_vid(slave, upper->dev_addr,
                                         tags[0].vlan_proto, tags[0].vlan_id);
+                        kfree(tags);
                 }
         }
         rcu_read_unlock();
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 14f789551616..023ec365209c 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -2145,7 +2145,7 @@ static void bond_arp_send(struct net_device *slave_dev, int arp_op,
                           struct bond_vlan_tag *tags)
 {
         struct sk_buff *skb;
-        int i;
+        struct bond_vlan_tag *outer_tag = tags;
 
         netdev_dbg(slave_dev, "arp %d on slave %s: dst %pI4 src %pI4\n",
                    arp_op, slave_dev->name, &dest_ip, &src_ip);
@@ -2158,30 +2158,42 @@ static void bond_arp_send(struct net_device *slave_dev, int arp_op,
                 return;
         }
 
+        if (!tags || tags->vlan_proto == VLAN_N_VID)
+                goto xmit;
+
+        tags++;
+
         /* Go through all the tags backwards and add them to the packet */
-        for (i = BOND_MAX_VLAN_ENCAP - 1; i > 0; i--) {
-                if (!tags[i].vlan_id)
+        while (tags->vlan_proto != VLAN_N_VID) {
+                if (!tags->vlan_id) {
+                        tags++;
                         continue;
+                }
 
                 netdev_dbg(slave_dev, "inner tag: proto %X vid %X\n",
-                           ntohs(tags[i].vlan_proto), tags[i].vlan_id);
-                skb = __vlan_put_tag(skb, tags[i].vlan_proto,
-                                     tags[i].vlan_id);
+                           ntohs(outer_tag->vlan_proto), tags->vlan_id);
+                skb = __vlan_put_tag(skb, tags->vlan_proto,
+                                     tags->vlan_id);
                 if (!skb) {
                         net_err_ratelimited("failed to insert inner VLAN tag\n");
                         return;
                 }
+
+                tags++;
         }
         /* Set the outer tag */
-        if (tags[0].vlan_id) {
+        if (outer_tag->vlan_id) {
                 netdev_dbg(slave_dev, "outer tag: proto %X vid %X\n",
-                           ntohs(tags[0].vlan_proto), tags[0].vlan_id);
-                skb = vlan_put_tag(skb, tags[0].vlan_proto, tags[0].vlan_id);
+                           ntohs(outer_tag->vlan_proto), outer_tag->vlan_id);
+                skb = vlan_put_tag(skb, outer_tag->vlan_proto,
+                                   outer_tag->vlan_id);
                 if (!skb) {
                         net_err_ratelimited("failed to insert outer VLAN tag\n");
                         return;
                 }
         }
+
+xmit:
         arp_xmit(skb);
 }
 
@@ -2191,46 +2203,50 @@ static void bond_arp_send(struct net_device *slave_dev, int arp_op,
  * When the path is validated, collect any vlan information in the
  * path.
  */
-bool bond_verify_device_path(struct net_device *start_dev,
-                             struct net_device *end_dev,
-                             struct bond_vlan_tag *tags)
+struct bond_vlan_tag *bond_verify_device_path(struct net_device *start_dev,
+                                              struct net_device *end_dev,
+                                              int level)
 {
+        struct bond_vlan_tag *tags;
         struct net_device *upper;
         struct list_head  *iter;
-        int  idx;
 
-        if (start_dev == end_dev)
-                return true;
+        if (start_dev == end_dev) {
+                tags = kzalloc(sizeof(*tags) * (level + 1), GFP_ATOMIC);
+                if (!tags)
+                        return ERR_PTR(-ENOMEM);
+                tags[level].vlan_proto = VLAN_N_VID;
+                return tags;
+        }
 
         netdev_for_each_upper_dev_rcu(start_dev, upper, iter) {
-                if (bond_verify_device_path(upper, end_dev, tags)) {
-                        if (is_vlan_dev(upper)) {
-                                idx = vlan_get_encap_level(upper);
-                                if (idx >= BOND_MAX_VLAN_ENCAP)
-                                        return false;
-
-                                tags[idx].vlan_proto =
-                                                    vlan_dev_vlan_proto(upper);
-                                tags[idx].vlan_id = vlan_dev_vlan_id(upper);
-                        }
-                        return true;
+                tags = bond_verify_device_path(upper, end_dev, level + 1);
+                if (IS_ERR_OR_NULL(tags)) {
+                        if (IS_ERR(tags))
+                                return tags;
+                        continue;
                 }
+                if (is_vlan_dev(upper)) {
+                        tags[level].vlan_proto = vlan_dev_vlan_proto(upper);
+                        tags[level].vlan_id = vlan_dev_vlan_id(upper);
+                }
+
+                return tags;
         }
 
-        return false;
+        return NULL;
 }
 
 static void bond_arp_send_all(struct bonding *bond, struct slave *slave)
 {
         struct rtable *rt;
-        struct bond_vlan_tag tags[BOND_MAX_VLAN_ENCAP];
+        struct bond_vlan_tag *tags;
         __be32 *targets = bond->params.arp_targets, addr;
         int i;
-        bool ret;
 
         for (i = 0; i < BOND_MAX_ARP_TARGETS && targets[i]; i++) {
                 netdev_dbg(bond->dev, "basa: target %pI4\n", &targets[i]);
-                memset(tags, 0, sizeof(tags));
+                tags = NULL;
 
                 /* Find out through which dev should the packet go */
                 rt = ip_route_output(dev_net(bond->dev), targets[i], 0,
@@ -2253,10 +2269,10 @@ static void bond_arp_send_all(struct bonding *bond, struct slave *slave)
                         goto found;
 
                 rcu_read_lock();
-                ret = bond_verify_device_path(bond->dev, rt->dst.dev, tags);
+                tags = bond_verify_device_path(bond->dev, rt->dst.dev, 0);
                 rcu_read_unlock();
 
-                if (ret)
+                if (!IS_ERR_OR_NULL(tags))
                         goto found;
 
                 /* Not our device - skip */
@@ -2271,6 +2287,8 @@ found:
                 ip_rt_put(rt);
                 bond_arp_send(slave->dev, ARPOP_REQUEST, targets[i],
                               addr, tags);
+                if (!tags)
+                        kfree(tags);
         }
 }
 
diff --git a/drivers/net/bonding/bonding.h b/drivers/net/bonding/bonding.h
index a85ca51eabf5..aace510d08d1 100644
--- a/drivers/net/bonding/bonding.h
+++ b/drivers/net/bonding/bonding.h
@@ -36,7 +36,6 @@
 
 #define bond_version DRV_DESCRIPTION ": v" DRV_VERSION " (" DRV_RELDATE ")\n"
 
-#define BOND_MAX_VLAN_ENCAP     2
 #define BOND_MAX_ARP_TARGETS    16
 
 #define BOND_DEFAULT_MIIMON     100
@@ -525,9 +524,9 @@ int bond_netlink_init(void);
 void bond_netlink_fini(void);
 struct net_device *bond_option_active_slave_get_rcu(struct bonding *bond);
 const char *bond_slave_link_status(s8 link);
-bool bond_verify_device_path(struct net_device *start_dev,
-                             struct net_device *end_dev,
-                             struct bond_vlan_tag *tags);
+struct bond_vlan_tag *bond_verify_device_path(struct net_device *start_dev,
+                                              struct net_device *end_dev,
+                                              int level);
 
 #ifdef CONFIG_PROC_FS
 void bond_create_proc_entry(struct bonding *bond);