/*
   * 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/fib_rules.h>

  #include <net/l3mdev.h>
  
  /**
   *	l3mdev_master_ifindex - get index of L3 master device
   *	@dev: targeted interface
   */

  int l3mdev_master_ifindex_rcu(const struct net_device *dev)

  {
  	int ifindex = 0;
  
  	if (!dev)
  		return 0;
  
  	if (netif_is_l3_master(dev)) {
  		ifindex = dev->ifindex;

  	} else if (netif_is_l3_slave(dev)) {

  		struct net_device *master;

  		struct net_device *_dev = (struct net_device *)dev;
  
  		/* netdev_master_upper_dev_get_rcu calls
  		 * list_first_or_null_rcu to walk the upper dev list.
  		 * list_first_or_null_rcu does not handle a const arg. We aren't
  		 * making changes, just want the master device from that list so
  		 * typecast to remove the const
  		 */
  		master = netdev_master_upper_dev_get_rcu(_dev);

  		if (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 (netif_is_l3_slave(dev)) {

  		/* 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 &&

  		    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);

  
  /**

   *	l3mdev_link_scope_lookup - IPv6 route lookup based on flow for link
   *			     local and multicast addresses

   *	@net: network namespace for device index lookup
   *	@fl6: IPv6 flow struct for lookup
   */

  struct dst_entry *l3mdev_link_scope_lookup(struct net *net,
  					   struct flowi6 *fl6)

  {
  	struct dst_entry *dst = NULL;
  	struct net_device *dev;

  	if (fl6->flowi6_oif) {
  		rcu_read_lock();
  
  		dev = dev_get_by_index_rcu(net, fl6->flowi6_oif);
  		if (dev && netif_is_l3_slave(dev))
  			dev = netdev_master_upper_dev_get_rcu(dev);
  
  		if (dev && netif_is_l3_master(dev) &&

  		    dev->l3mdev_ops->l3mdev_link_scope_lookup)
  			dst = dev->l3mdev_ops->l3mdev_link_scope_lookup(dev, fl6);

  
  		rcu_read_unlock();

  	}
  
  	return dst;
  }

  EXPORT_SYMBOL_GPL(l3mdev_link_scope_lookup);

  /**
   *	l3mdev_fib_rule_match - Determine if flowi references an
   *				L3 master device
   *	@net: network namespace for device index lookup
   *	@fl:  flow struct
   */
  
  int l3mdev_fib_rule_match(struct net *net, struct flowi *fl,
  			  struct fib_lookup_arg *arg)
  {
  	struct net_device *dev;
  	int rc = 0;
  
  	rcu_read_lock();
  
  	dev = dev_get_by_index_rcu(net, fl->flowi_oif);
  	if (dev && netif_is_l3_master(dev) &&
  	    dev->l3mdev_ops->l3mdev_fib_table) {
  		arg->table = dev->l3mdev_ops->l3mdev_fib_table(dev);
  		rc = 1;
  		goto out;
  	}
  
  	dev = dev_get_by_index_rcu(net, fl->flowi_iif);
  	if (dev && netif_is_l3_master(dev) &&
  	    dev->l3mdev_ops->l3mdev_fib_table) {
  		arg->table = dev->l3mdev_ops->l3mdev_fib_table(dev);
  		rc = 1;
  		goto out;
  	}
  
  out:
  	rcu_read_unlock();
  
  	return rc;
  }

  
  void l3mdev_update_flow(struct net *net, struct flowi *fl)
  {
  	struct net_device *dev;
  	int ifindex;
  
  	rcu_read_lock();
  
  	if (fl->flowi_oif) {
  		dev = dev_get_by_index_rcu(net, fl->flowi_oif);
  		if (dev) {
  			ifindex = l3mdev_master_ifindex_rcu(dev);
  			if (ifindex) {
  				fl->flowi_oif = ifindex;
  				fl->flowi_flags |= FLOWI_FLAG_SKIP_NH_OIF;
  				goto out;
  			}
  		}
  	}
  
  	if (fl->flowi_iif) {
  		dev = dev_get_by_index_rcu(net, fl->flowi_iif);
  		if (dev) {
  			ifindex = l3mdev_master_ifindex_rcu(dev);
  			if (ifindex) {
  				fl->flowi_iif = ifindex;
  				fl->flowi_flags |= FLOWI_FLAG_SKIP_NH_OIF;
  			}
  		}
  	}
  
  out:
  	rcu_read_unlock();
  }
  EXPORT_SYMBOL_GPL(l3mdev_update_flow);