Commit 5eb902b8 authored by Kui-Feng Lee's avatar Kui-Feng Lee Committed by David S. Miller
Browse files

net/ipv6: Remove expired routes with a separated list of routes. 



FIB6 GC walks trees of fib6_tables to remove expired routes. Walking a tree
can be expensive if the number of routes in a table is big, even if most of
them are permanent. Checking routes in a separated list of routes having
expiration will avoid this potential issue.

Reviewed-by: default avatarDavid Ahern <dsahern@kernel.org>
Signed-off-by: default avatarKui-Feng Lee <thinker.li@gmail.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 60df43d3

include/net/ip6_fib.h

+45 −1
Original line number Diff line number Diff line
@@ -173,6 +173,9 @@ struct fib6_info { 


	refcount_t			fib6_ref;

	unsigned long			expires;



	struct hlist_node		gc_link;



	struct dst_metrics		*fib6_metrics;

#define fib6_pmtu		fib6_metrics->metrics[RTAX_MTU-1]
@@ -241,12 +244,18 @@ static inline bool fib6_requires_src(const struct fib6_info *rt) 
	return rt->fib6_src.plen > 0;

}



/* The callers should hold f6i->fib6_table->tb6_lock if a route has ever

 * been added to a table before.

 */

static inline void fib6_clean_expires(struct fib6_info *f6i)

{

	f6i->fib6_flags &= ~RTF_EXPIRES;

	f6i->expires = 0;

}



/* The callers should hold f6i->fib6_table->tb6_lock if a route has ever

 * been added to a table before.

 */

static inline void fib6_set_expires(struct fib6_info *f6i,

				    unsigned long expires)

{
@@ -327,9 +336,11 @@ static inline bool fib6_info_hold_safe(struct fib6_info *f6i) 


static inline void fib6_info_release(struct fib6_info *f6i)

{

	if (f6i && refcount_dec_and_test(&f6i->fib6_ref))

	if (f6i && refcount_dec_and_test(&f6i->fib6_ref)) {

		DEBUG_NET_WARN_ON_ONCE(!hlist_unhashed(&f6i->gc_link));

		call_rcu(&f6i->rcu, fib6_info_destroy_rcu);

	}

}



enum fib6_walk_state {

#ifdef CONFIG_IPV6_SUBTREES
@@ -382,6 +393,7 @@ struct fib6_table { 
	struct inet_peer_base	tb6_peers;

	unsigned int		flags;

	unsigned int		fib_seq;

	struct hlist_head       tb6_gc_hlist;	/* GC candidates */

#define RT6_TABLE_HAS_DFLT_ROUTER	BIT(0)

};
@@ -498,6 +510,38 @@ void fib6_gc_cleanup(void); 


int fib6_init(void);



/* Add the route to the gc list if it is not already there

 *

 * The callers should hold f6i->fib6_table->tb6_lock.

 */

static inline void fib6_add_gc_list(struct fib6_info *f6i)

{

	/* If fib6_node is null, the f6i is not in (or removed from) the

	 * table.

	 *

	 * There is a gap between finding the f6i from the table and

	 * calling this function without the protection of the tb6_lock.

	 * This check makes sure the f6i is not added to the gc list when

	 * it is not on the table.

	 */

	if (!rcu_dereference_protected(f6i->fib6_node,

				       lockdep_is_held(&f6i->fib6_table->tb6_lock)))

		return;



	if (hlist_unhashed(&f6i->gc_link))

		hlist_add_head(&f6i->gc_link, &f6i->fib6_table->tb6_gc_hlist);

}



/* Remove the route from the gc list if it is on the list.

 *

 * The callers should hold f6i->fib6_table->tb6_lock.

 */

static inline void fib6_remove_gc_list(struct fib6_info *f6i)

{

	if (!hlist_unhashed(&f6i->gc_link))

		hlist_del_init(&f6i->gc_link);

}



struct ipv6_route_iter {

	struct seq_net_private p;

	struct fib6_walker w;

net/ipv6/addrconf.c

+34 −7
Original line number Diff line number Diff line
@@ -1255,6 +1255,7 @@ static void 
cleanup_prefix_route(struct inet6_ifaddr *ifp, unsigned long expires,

		     bool del_rt, bool del_peer)

{

	struct fib6_table *table;

	struct fib6_info *f6i;



	f6i = addrconf_get_prefix_route(del_peer ? &ifp->peer_addr : &ifp->addr,
@@ -1264,8 +1265,15 @@ cleanup_prefix_route(struct inet6_ifaddr *ifp, unsigned long expires, 
		if (del_rt)

			ip6_del_rt(dev_net(ifp->idev->dev), f6i, false);

		else {

			if (!(f6i->fib6_flags & RTF_EXPIRES))

			if (!(f6i->fib6_flags & RTF_EXPIRES)) {

				table = f6i->fib6_table;

				spin_lock_bh(&table->tb6_lock);



				fib6_set_expires(f6i, expires);

				fib6_add_gc_list(f6i);



				spin_unlock_bh(&table->tb6_lock);

			}

			fib6_info_release(f6i);

		}

	}
@@ -2706,6 +2714,7 @@ EXPORT_SYMBOL_GPL(addrconf_prefix_rcv_add_addr); 
void addrconf_prefix_rcv(struct net_device *dev, u8 *opt, int len, bool sllao)

{

	struct prefix_info *pinfo;

	struct fib6_table *table;

	__u32 valid_lft;

	__u32 prefered_lft;

	int addr_type, err;
@@ -2782,11 +2791,20 @@ void addrconf_prefix_rcv(struct net_device *dev, u8 *opt, int len, bool sllao) 
			if (valid_lft == 0) {

				ip6_del_rt(net, rt, false);

				rt = NULL;

			} else if (addrconf_finite_timeout(rt_expires)) {

			} else {

				table = rt->fib6_table;

				spin_lock_bh(&table->tb6_lock);



				if (addrconf_finite_timeout(rt_expires)) {

					/* not infinity */

					fib6_set_expires(rt, jiffies + rt_expires);

					fib6_add_gc_list(rt);

				} else {

					fib6_clean_expires(rt);

					fib6_remove_gc_list(rt);

				}



				spin_unlock_bh(&table->tb6_lock);

			}

		} else if (valid_lft) {

			clock_t expires = 0;
@@ -4741,6 +4759,7 @@ static int modify_prefix_route(struct inet6_ifaddr *ifp, 
			       unsigned long expires, u32 flags,

			       bool modify_peer)

{

	struct fib6_table *table;

	struct fib6_info *f6i;

	u32 prio;
@@ -4761,10 +4780,18 @@ static int modify_prefix_route(struct inet6_ifaddr *ifp, 
				      ifp->rt_priority, ifp->idev->dev,

				      expires, flags, GFP_KERNEL);

	} else {

		if (!expires)

		table = f6i->fib6_table;

		spin_lock_bh(&table->tb6_lock);



		if (!expires) {

			fib6_clean_expires(f6i);

		else

			fib6_remove_gc_list(f6i);

		} else {

			fib6_set_expires(f6i, expires);

			fib6_add_gc_list(f6i);

		}



		spin_unlock_bh(&table->tb6_lock);



		fib6_info_release(f6i);

	}

net/ipv6/ip6_fib.c

+55 −5
Original line number Diff line number Diff line
@@ -160,6 +160,8 @@ struct fib6_info *fib6_info_alloc(gfp_t gfp_flags, bool with_fib6_nh) 
	INIT_LIST_HEAD(&f6i->fib6_siblings);

	refcount_set(&f6i->fib6_ref, 1);



	INIT_HLIST_NODE(&f6i->gc_link);



	return f6i;

}
@@ -246,6 +248,7 @@ static struct fib6_table *fib6_alloc_table(struct net *net, u32 id) 
				   net->ipv6.fib6_null_entry);

		table->tb6_root.fn_flags = RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;

		inet_peer_base_init(&table->tb6_peers);

		INIT_HLIST_HEAD(&table->tb6_gc_hlist);

	}



	return table;
@@ -1055,6 +1058,9 @@ static void fib6_purge_rt(struct fib6_info *rt, struct fib6_node *fn, 
				    lockdep_is_held(&table->tb6_lock));

		}

	}



	fib6_clean_expires(rt);

	fib6_remove_gc_list(rt);

}



/*
@@ -1115,10 +1121,13 @@ static int fib6_add_rt2node(struct fib6_node *fn, struct fib6_info *rt, 
					rt->fib6_nsiblings = 0;

				if (!(iter->fib6_flags & RTF_EXPIRES))

					return -EEXIST;

				if (!(rt->fib6_flags & RTF_EXPIRES))

				if (!(rt->fib6_flags & RTF_EXPIRES)) {

					fib6_clean_expires(iter);

				else

					fib6_remove_gc_list(iter);

				} else {

					fib6_set_expires(iter, rt->expires);

					fib6_add_gc_list(iter);

				}



				if (rt->fib6_pmtu)

					fib6_metric_set(iter, RTAX_MTU,
@@ -1477,6 +1486,10 @@ int fib6_add(struct fib6_node *root, struct fib6_info *rt, 
		if (rt->nh)

			list_add(&rt->nh_list, &rt->nh->f6i_list);

		__fib6_update_sernum_upto_root(rt, fib6_new_sernum(info->nl_net));



		if (rt->fib6_flags & RTF_EXPIRES)

			fib6_add_gc_list(rt);



		fib6_start_gc(info->nl_net, rt);

	}
@@ -2280,9 +2293,8 @@ static void fib6_flush_trees(struct net *net) 
 *	Garbage collection

 */



static int fib6_age(struct fib6_info *rt, void *arg)

static int fib6_age(struct fib6_info *rt, struct fib6_gc_args *gc_args)

{

	struct fib6_gc_args *gc_args = arg;

	unsigned long now = jiffies;



	/*
@@ -2307,6 +2319,42 @@ static int fib6_age(struct fib6_info *rt, void *arg) 
	return 0;

}



static void fib6_gc_table(struct net *net,

			  struct fib6_table *tb6,

			  struct fib6_gc_args *gc_args)

{

	struct fib6_info *rt;

	struct hlist_node *n;

	struct nl_info info = {

		.nl_net = net,

		.skip_notify = false,

	};



	hlist_for_each_entry_safe(rt, n, &tb6->tb6_gc_hlist, gc_link)

		if (fib6_age(rt, gc_args) == -1)

			fib6_del(rt, &info);

}



static void fib6_gc_all(struct net *net, struct fib6_gc_args *gc_args)

{

	struct fib6_table *table;

	struct hlist_head *head;

	unsigned int h;



	rcu_read_lock();

	for (h = 0; h < FIB6_TABLE_HASHSZ; h++) {

		head = &net->ipv6.fib_table_hash[h];

		hlist_for_each_entry_rcu(table, head, tb6_hlist) {

			spin_lock_bh(&table->tb6_lock);



			fib6_gc_table(net, table, gc_args);



			spin_unlock_bh(&table->tb6_lock);

		}

	}

	rcu_read_unlock();

}



void fib6_run_gc(unsigned long expires, struct net *net, bool force)

{

	struct fib6_gc_args gc_args;
@@ -2322,7 +2370,7 @@ void fib6_run_gc(unsigned long expires, struct net *net, bool force) 
			  net->ipv6.sysctl.ip6_rt_gc_interval;

	gc_args.more = 0;



	fib6_clean_all(net, fib6_age, &gc_args);

	fib6_gc_all(net, &gc_args);

	now = jiffies;

	net->ipv6.ip6_rt_last_gc = now;
@@ -2382,6 +2430,7 @@ static int __net_init fib6_net_init(struct net *net) 
	net->ipv6.fib6_main_tbl->tb6_root.fn_flags =

		RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;

	inet_peer_base_init(&net->ipv6.fib6_main_tbl->tb6_peers);

	INIT_HLIST_HEAD(&net->ipv6.fib6_main_tbl->tb6_gc_hlist);



#ifdef CONFIG_IPV6_MULTIPLE_TABLES

	net->ipv6.fib6_local_tbl = kzalloc(sizeof(*net->ipv6.fib6_local_tbl),
@@ -2394,6 +2443,7 @@ static int __net_init fib6_net_init(struct net *net) 
	net->ipv6.fib6_local_tbl->tb6_root.fn_flags =

		RTN_ROOT | RTN_TL_ROOT | RTN_RTINFO;

	inet_peer_base_init(&net->ipv6.fib6_local_tbl->tb6_peers);

	INIT_HLIST_HEAD(&net->ipv6.fib6_local_tbl->tb6_gc_hlist);

#endif

	fib6_tables_init(net);

net/ipv6/ndisc.c

+9 −1
Original line number Diff line number Diff line
@@ -1237,6 +1237,7 @@ static enum skb_drop_reason ndisc_router_discovery(struct sk_buff *skb) 
	struct ndisc_options ndopts;

	struct fib6_info *rt = NULL;

	struct inet6_dev *in6_dev;

	struct fib6_table *table;

	u32 defrtr_usr_metric;

	unsigned int pref = 0;

	__u32 old_if_flags;
@@ -1410,8 +1411,15 @@ static enum skb_drop_reason ndisc_router_discovery(struct sk_buff *skb) 
		inet6_rt_notify(RTM_NEWROUTE, rt, &nlinfo, NLM_F_REPLACE);

	}



	if (rt)

	if (rt) {

		table = rt->fib6_table;

		spin_lock_bh(&table->tb6_lock);



		fib6_set_expires(rt, jiffies + (HZ * lifetime));

		fib6_add_gc_list(rt);



		spin_unlock_bh(&table->tb6_lock);

	}

	if (in6_dev->cnf.accept_ra_min_hop_limit < 256 &&

	    ra_msg->icmph.icmp6_hop_limit) {

		if (in6_dev->cnf.accept_ra_min_hop_limit <= ra_msg->icmph.icmp6_hop_limit) {

net/ipv6/route.c

+11 −2
Original line number Diff line number Diff line
@@ -931,6 +931,7 @@ int rt6_route_rcv(struct net_device *dev, u8 *opt, int len, 
	struct net *net = dev_net(dev);

	struct route_info *rinfo = (struct route_info *) opt;

	struct in6_addr prefix_buf, *prefix;

	struct fib6_table *table;

	unsigned int pref;

	unsigned long lifetime;

	struct fib6_info *rt;
@@ -989,10 +990,18 @@ int rt6_route_rcv(struct net_device *dev, u8 *opt, int len, 
				 (rt->fib6_flags & ~RTF_PREF_MASK) | RTF_PREF(pref);



	if (rt) {

		if (!addrconf_finite_timeout(lifetime))

		table = rt->fib6_table;

		spin_lock_bh(&table->tb6_lock);



		if (!addrconf_finite_timeout(lifetime)) {

			fib6_clean_expires(rt);

		else

			fib6_remove_gc_list(rt);

		} else {

			fib6_set_expires(rt, jiffies + HZ * lifetime);

			fib6_add_gc_list(rt);

		}



		spin_unlock_bh(&table->tb6_lock);



		fib6_info_release(rt);

	}