net: Introduce L3 Master device abstraction
L3 master devices allow users of the abstraction to influence FIB lookups
for enslaved devices. Current API provides a means for the master device
to return a specific FIB table for an enslaved device, to return an
rtable/custom dst and influence the OIF used for fib lookups.
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/l3mdev/l3mdev.c b/net/l3mdev/l3mdev.c
new file mode 100644
index 0000000..ddf75ad
--- /dev/null
+++ b/net/l3mdev/l3mdev.c
@@ -0,0 +1,92 @@
+/*
+ * net/l3mdev/l3mdev.c - L3 master device implementation
+ * Copyright (c) 2015 Cumulus Networks
+ * Copyright (c) 2015 David Ahern <dsa@cumulusnetworks.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ */
+
+#include <linux/netdevice.h>
+#include <net/l3mdev.h>
+
+/**
+ * l3mdev_master_ifindex - get index of L3 master device
+ * @dev: targeted interface
+ */
+
+int l3mdev_master_ifindex_rcu(struct net_device *dev)
+{
+ int ifindex = 0;
+
+ if (!dev)
+ return 0;
+
+ if (netif_is_l3_master(dev)) {
+ ifindex = dev->ifindex;
+ } else if (dev->flags & IFF_SLAVE) {
+ struct net_device *master;
+
+ master = netdev_master_upper_dev_get_rcu(dev);
+ if (master && netif_is_l3_master(master))
+ ifindex = master->ifindex;
+ }
+
+ return ifindex;
+}
+EXPORT_SYMBOL_GPL(l3mdev_master_ifindex_rcu);
+
+/**
+ * l3mdev_fib_table - get FIB table id associated with an L3
+ * master interface
+ * @dev: targeted interface
+ */
+
+u32 l3mdev_fib_table_rcu(const struct net_device *dev)
+{
+ u32 tb_id = 0;
+
+ if (!dev)
+ return 0;
+
+ if (netif_is_l3_master(dev)) {
+ if (dev->l3mdev_ops->l3mdev_fib_table)
+ tb_id = dev->l3mdev_ops->l3mdev_fib_table(dev);
+ } else if (dev->flags & IFF_SLAVE) {
+ /* Users of netdev_master_upper_dev_get_rcu need non-const,
+ * but current inet_*type functions take a const
+ */
+ struct net_device *_dev = (struct net_device *) dev;
+ const struct net_device *master;
+
+ master = netdev_master_upper_dev_get_rcu(_dev);
+ if (master && netif_is_l3_master(master) &&
+ master->l3mdev_ops->l3mdev_fib_table)
+ tb_id = master->l3mdev_ops->l3mdev_fib_table(master);
+ }
+
+ return tb_id;
+}
+EXPORT_SYMBOL_GPL(l3mdev_fib_table_rcu);
+
+u32 l3mdev_fib_table_by_index(struct net *net, int ifindex)
+{
+ struct net_device *dev;
+ u32 tb_id = 0;
+
+ if (!ifindex)
+ return 0;
+
+ rcu_read_lock();
+
+ dev = dev_get_by_index_rcu(net, ifindex);
+ if (dev)
+ tb_id = l3mdev_fib_table_rcu(dev);
+
+ rcu_read_unlock();
+
+ return tb_id;
+}
+EXPORT_SYMBOL_GPL(l3mdev_fib_table_by_index);