net/l3mdev/l3mdev.c - linux - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  * net/l3mdev/l3mdev.c - L3 master device implementation
  * Copyright (c) 2015 Cumulus Networks
  * Copyright (c) 2015 David Ahern <dsa@cumulusnetworks.com>
  */

 #include <linux/netdevice.h>
 #include <net/fib_rules.h>
 #include <net/l3mdev.h>

 static DEFINE_SPINLOCK(l3mdev_lock);

 struct l3mdev_handler {
 	lookup_by_table_id_t dev_lookup;
 };

 static struct l3mdev_handler l3mdev_handlers[L3MDEV_TYPE_MAX + 1];

 static int l3mdev_check_type(enum l3mdev_type l3type)
 {
 	if (l3type <= L3MDEV_TYPE_UNSPEC || l3type > L3MDEV_TYPE_MAX)
 		return -EINVAL;

 	return 0;
 }

 int l3mdev_table_lookup_register(enum l3mdev_type l3type,
 				 lookup_by_table_id_t fn)
 {
 	struct l3mdev_handler *hdlr;
 	int res;

 	res = l3mdev_check_type(l3type);
 	if (res)
 		return res;

 	hdlr = &l3mdev_handlers[l3type];

 	spin_lock(&l3mdev_lock);

 	if (hdlr->dev_lookup) {
 		res = -EBUSY;
 		goto unlock;
 	}

 	hdlr->dev_lookup = fn;
 	res = 0;

 unlock:
 	spin_unlock(&l3mdev_lock);

 	return res;
 }
 EXPORT_SYMBOL_GPL(l3mdev_table_lookup_register);

 void l3mdev_table_lookup_unregister(enum l3mdev_type l3type,
 				    lookup_by_table_id_t fn)
 {
 	struct l3mdev_handler *hdlr;

 	if (l3mdev_check_type(l3type))
 		return;

 	hdlr = &l3mdev_handlers[l3type];

 	spin_lock(&l3mdev_lock);

 	if (hdlr->dev_lookup == fn)
 		hdlr->dev_lookup = NULL;

 	spin_unlock(&l3mdev_lock);
 }
 EXPORT_SYMBOL_GPL(l3mdev_table_lookup_unregister);

 int l3mdev_ifindex_lookup_by_table_id(enum l3mdev_type l3type,
 				      struct net *net, u32 table_id)
 {
 	lookup_by_table_id_t lookup;
 	struct l3mdev_handler *hdlr;
 	int ifindex = -EINVAL;
 	int res;

 	res = l3mdev_check_type(l3type);
 	if (res)
 		return res;

 	hdlr = &l3mdev_handlers[l3type];

 	spin_lock(&l3mdev_lock);

 	lookup = hdlr->dev_lookup;
 	if (!lookup)
 		goto unlock;

 	ifindex = lookup(net, table_id);

 unlock:
 	spin_unlock(&l3mdev_lock);

 	return ifindex;
 }
 EXPORT_SYMBOL_GPL(l3mdev_ifindex_lookup_by_table_id);

 /**
  *	l3mdev_master_ifindex_rcu - 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_master_upper_ifindex_by_index_rcu - 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_rcu(dev);

 	return dev ? dev->ifindex : 0;
 }
 EXPORT_SYMBOL_GPL(l3mdev_master_upper_ifindex_by_index_rcu);

 /**
  *	l3mdev_fib_table_rcu - 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
  *	This function does not hold refcnt on the returned dst.
  *	Caller must hold rcu_read_lock().
  */

 struct dst_entry *l3mdev_link_scope_lookup(struct net *net,
 					   struct flowi6 *fl6)
 {
 	struct dst_entry *dst = NULL;
 	struct net_device *dev;

 	WARN_ON_ONCE(!rcu_read_lock_held());
 	if (fl6->flowi6_oif) {
 		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);
 	}

 	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
  *	@arg: store the table the rule matched with here
  */

 int l3mdev_fib_rule_match(struct net *net, struct flowi *fl,
 			  struct fib_lookup_arg *arg)
 {
 	struct net_device *dev;
 	int rc = 0;

 	/* update flow ensures flowi_l3mdev is set when relevant */
 	if (!fl->flowi_l3mdev)
 		return 0;

 	rcu_read_lock();

 	dev = dev_get_by_index_rcu(net, fl->flowi_l3mdev);
 	if (dev && netif_is_l3_master(dev) &&
 	    dev->l3mdev_ops->l3mdev_fib_table) {
 		arg->table = dev->l3mdev_ops->l3mdev_fib_table(dev);
 		rc = 1;
 	}

 	rcu_read_unlock();

 	return rc;
 }

 void l3mdev_update_flow(struct net *net, struct flowi *fl)
 {
 	struct net_device *dev;

 	rcu_read_lock();

 	if (fl->flowi_oif) {
 		dev = dev_get_by_index_rcu(net, fl->flowi_oif);
 		if (dev) {
 			if (!fl->flowi_l3mdev)
 				fl->flowi_l3mdev = l3mdev_master_ifindex_rcu(dev);

 			/* oif set to L3mdev directs lookup to its table;
 			 * reset to avoid oif match in fib_lookup
 			 */
 			if (netif_is_l3_master(dev))
 				fl->flowi_oif = 0;
 			goto out;
 		}
 	}

 	if (fl->flowi_iif > LOOPBACK_IFINDEX && !fl->flowi_l3mdev) {
 		dev = dev_get_by_index_rcu(net, fl->flowi_iif);
 		if (dev)
 			fl->flowi_l3mdev = l3mdev_master_ifindex_rcu(dev);
 	}

 out:
 	rcu_read_unlock();
 }
 EXPORT_SYMBOL_GPL(l3mdev_update_flow);
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* net/l3mdev/l3mdev.c - L3 master device implementation
	* Copyright (c) 2015 Cumulus Networks
	* Copyright (c) 2015 David Ahern <dsa@cumulusnetworks.com>
	*/

	#include <linux/netdevice.h>
	#include <net/fib_rules.h>
	#include <net/l3mdev.h>

	static DEFINE_SPINLOCK(l3mdev_lock);

	struct l3mdev_handler {
	lookup_by_table_id_t dev_lookup;
	};

	static struct l3mdev_handler l3mdev_handlers[L3MDEV_TYPE_MAX + 1];

	static int l3mdev_check_type(enum l3mdev_type l3type)
	{
	if (l3type <= L3MDEV_TYPE_UNSPEC \|\| l3type > L3MDEV_TYPE_MAX)
	return -EINVAL;

	return 0;
	}

	int l3mdev_table_lookup_register(enum l3mdev_type l3type,
	lookup_by_table_id_t fn)
	{
	struct l3mdev_handler *hdlr;
	int res;

	res = l3mdev_check_type(l3type);
	if (res)
	return res;

	hdlr = &l3mdev_handlers[l3type];

	spin_lock(&l3mdev_lock);

	if (hdlr->dev_lookup) {
	res = -EBUSY;
	goto unlock;
	}

	hdlr->dev_lookup = fn;
	res = 0;

	unlock:
	spin_unlock(&l3mdev_lock);

	return res;
	}
	EXPORT_SYMBOL_GPL(l3mdev_table_lookup_register);

	void l3mdev_table_lookup_unregister(enum l3mdev_type l3type,
	lookup_by_table_id_t fn)
	{
	struct l3mdev_handler *hdlr;

	if (l3mdev_check_type(l3type))
	return;

	hdlr = &l3mdev_handlers[l3type];

	spin_lock(&l3mdev_lock);

	if (hdlr->dev_lookup == fn)
	hdlr->dev_lookup = NULL;

	spin_unlock(&l3mdev_lock);
	}
	EXPORT_SYMBOL_GPL(l3mdev_table_lookup_unregister);

	int l3mdev_ifindex_lookup_by_table_id(enum l3mdev_type l3type,
	struct net *net, u32 table_id)
	{
	lookup_by_table_id_t lookup;
	struct l3mdev_handler *hdlr;
	int ifindex = -EINVAL;
	int res;

	res = l3mdev_check_type(l3type);
	if (res)
	return res;

	hdlr = &l3mdev_handlers[l3type];

	spin_lock(&l3mdev_lock);

	lookup = hdlr->dev_lookup;
	if (!lookup)
	goto unlock;

	ifindex = lookup(net, table_id);

	unlock:
	spin_unlock(&l3mdev_lock);

	return ifindex;
	}
	EXPORT_SYMBOL_GPL(l3mdev_ifindex_lookup_by_table_id);

	/**
	* l3mdev_master_ifindex_rcu - 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_master_upper_ifindex_by_index_rcu - 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_rcu(dev);

	return dev ? dev->ifindex : 0;
	}
	EXPORT_SYMBOL_GPL(l3mdev_master_upper_ifindex_by_index_rcu);

	/**
	* l3mdev_fib_table_rcu - 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
	* This function does not hold refcnt on the returned dst.
	* Caller must hold rcu_read_lock().
	*/

	struct dst_entry l3mdev_link_scope_lookup(struct net net,
	struct flowi6 *fl6)
	{
	struct dst_entry *dst = NULL;
	struct net_device *dev;

	WARN_ON_ONCE(!rcu_read_lock_held());
	if (fl6->flowi6_oif) {
	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);
	}

	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
	* @arg: store the table the rule matched with here
	*/

	int l3mdev_fib_rule_match(struct net net, struct flowi fl,
	struct fib_lookup_arg *arg)
	{
	struct net_device *dev;
	int rc = 0;

	/* update flow ensures flowi_l3mdev is set when relevant */
	if (!fl->flowi_l3mdev)
	return 0;

	rcu_read_lock();

	dev = dev_get_by_index_rcu(net, fl->flowi_l3mdev);
	if (dev && netif_is_l3_master(dev) &&
	dev->l3mdev_ops->l3mdev_fib_table) {
	arg->table = dev->l3mdev_ops->l3mdev_fib_table(dev);
	rc = 1;
	}

	rcu_read_unlock();

	return rc;
	}

	void l3mdev_update_flow(struct net net, struct flowi fl)
	{
	struct net_device *dev;

	rcu_read_lock();

	if (fl->flowi_oif) {
	dev = dev_get_by_index_rcu(net, fl->flowi_oif);
	if (dev) {
	if (!fl->flowi_l3mdev)
	fl->flowi_l3mdev = l3mdev_master_ifindex_rcu(dev);

	/* oif set to L3mdev directs lookup to its table;
	* reset to avoid oif match in fib_lookup
	*/
	if (netif_is_l3_master(dev))
	fl->flowi_oif = 0;
	goto out;
	}
	}

	if (fl->flowi_iif > LOOPBACK_IFINDEX && !fl->flowi_l3mdev) {
	dev = dev_get_by_index_rcu(net, fl->flowi_iif);
	if (dev)
	fl->flowi_l3mdev = l3mdev_master_ifindex_rcu(dev);
	}

	out:
	rcu_read_unlock();
	}
	EXPORT_SYMBOL_GPL(l3mdev_update_flow);