l3mdev: add function to retreive upper master

Existing functions to retreive the l3mdev of a device did not walk the master chain to find the upper master. This patch adds a function to find the l3mdev, even indirect through e.g. a bridge: +----------+ | | | vrf-blue | | | +----+-----+ | | +----+-----+ | | | br-blue | | | +----+-----+ | | +----+-----+ | | | eth0 | | | +----------+ This will properly resolve the l3mdev of eth0 to vrf-blue. Signed-off-by: Alexis Bauvin <[email protected]> Reviewed-by: Amine Kherbouche <[email protected]> Reviewed-by: David Ahern <[email protected]> Tested-by: Amine Kherbouche <[email protected]> Signed-off-by: David S. Miller <[email protected]>
jic23 · Dec 3, 2018 · 6a6d668 · 6a6d668
1 parent da5095d
commit 6a6d668
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diff --git a/include/net/l3mdev.h b/include/net/l3mdev.h
@@ -101,6 +101,17 @@ struct net_device *l3mdev_master_dev_rcu(const struct net_device *_dev)
 	return master;
 }
 
+int l3mdev_master_upper_ifindex_by_index_rcu(struct net *net, int ifindex);
+static inline
+int l3mdev_master_upper_ifindex_by_index(struct net *net, int ifindex)
+{
+	rcu_read_lock();
+	ifindex = l3mdev_master_upper_ifindex_by_index_rcu(net, ifindex);
+	rcu_read_unlock();
+
+	return ifindex;
+}
+
 u32 l3mdev_fib_table_rcu(const struct net_device *dev);
 u32 l3mdev_fib_table_by_index(struct net *net, int ifindex);
 static inline u32 l3mdev_fib_table(const struct net_device *dev)
@@ -207,6 +218,17 @@ static inline int l3mdev_master_ifindex_by_index(struct net *net, int ifindex)
 	return 0;
 }
 
+static inline
+int l3mdev_master_upper_ifindex_by_index_rcu(struct net *net, int ifindex)
+{
+	return 0;
+}
+static inline
+int l3mdev_master_upper_ifindex_by_index(struct net *net, int ifindex)
+{
+	return 0;
+}
+
 static inline
 struct net_device *l3mdev_master_dev_rcu(const struct net_device *dev)
 {

diff --git a/net/l3mdev/l3mdev.c b/net/l3mdev/l3mdev.c
@@ -46,6 +46,24 @@ int l3mdev_master_ifindex_rcu(const struct net_device *dev)
 }
 EXPORT_SYMBOL_GPL(l3mdev_master_ifindex_rcu);
 
+/**
+ *	l3mdev_master_upper_ifindex_by_index - get index of upper l3 master
+ *					       device
+ *	@net: network namespace for device index lookup
+ *	@ifindex: targeted interface
+ */
+int l3mdev_master_upper_ifindex_by_index_rcu(struct net *net, int ifindex)
+{
+	struct net_device *dev;
+
+	dev = dev_get_by_index_rcu(net, ifindex);
+	while (dev && !netif_is_l3_master(dev))
+		dev = netdev_master_upper_dev_get(dev);
+
+	return dev ? dev->ifindex : 0;
+}
+EXPORT_SYMBOL_GPL(l3mdev_master_upper_ifindex_by_index_rcu);
+
 /**
  *	l3mdev_fib_table - get FIB table id associated with an L3
  *                             master interface