Commit f547fac6 authored by Sabrina Dubroca's avatar Sabrina Dubroca Committed by David S. Miller
Browse files

ipv6: rate-limit probes for neighbourless routes 



When commit 27097255 ("[IPV6]: ROUTE: Add Router Reachability
Probing (RFC4191).") introduced router probing, the rt6_probe() function
required that a neighbour entry existed. This neighbour entry is used to
record the timestamp of the last probe via the ->updated field.

Later, commit 2152caea ("ipv6: Do not depend on rt->n in rt6_probe().")
removed the requirement for a neighbour entry. Neighbourless routes skip
the interval check and are not rate-limited.

This patch adds rate-limiting for neighbourless routes, by recording the
timestamp of the last probe in the fib6_info itself.

Fixes: 2152caea ("ipv6: Do not depend on rt->n in rt6_probe().")
Signed-off-by: default avatarSabrina Dubroca <sd@queasysnail.net>
Reviewed-by: default avatarStefano Brivio <sbrivio@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 64bd9c81

include/net/ip6_fib.h

+4 −0
Original line number Diff line number Diff line
@@ -159,6 +159,10 @@ struct fib6_info { 
	struct rt6_info * __percpu	*rt6i_pcpu;

	struct rt6_exception_bucket __rcu *rt6i_exception_bucket;



#ifdef CONFIG_IPV6_ROUTER_PREF

	unsigned long			last_probe;

#endif



	u32				fib6_metric;

	u8				fib6_protocol;

	u8				fib6_type;

net/ipv6/route.c

+6 −6
Original line number Diff line number Diff line
@@ -520,10 +520,11 @@ static void rt6_probe_deferred(struct work_struct *w) 


static void rt6_probe(struct fib6_info *rt)

{

	struct __rt6_probe_work *work;

	struct __rt6_probe_work *work = NULL;

	const struct in6_addr *nh_gw;

	struct neighbour *neigh;

	struct net_device *dev;

	struct inet6_dev *idev;



	/*

	 * Okay, this does not seem to be appropriate
@@ -539,15 +540,12 @@ static void rt6_probe(struct fib6_info *rt) 
	nh_gw = &rt->fib6_nh.nh_gw;

	dev = rt->fib6_nh.nh_dev;

	rcu_read_lock_bh();

	idev = __in6_dev_get(dev);

	neigh = __ipv6_neigh_lookup_noref(dev, nh_gw);

	if (neigh) {

		struct inet6_dev *idev;



		if (neigh->nud_state & NUD_VALID)

			goto out;



		idev = __in6_dev_get(dev);

		work = NULL;

		write_lock(&neigh->lock);

		if (!(neigh->nud_state & NUD_VALID) &&

		    time_after(jiffies,
@@ -557,11 +555,13 @@ static void rt6_probe(struct fib6_info *rt) 
				__neigh_set_probe_once(neigh);

		}

		write_unlock(&neigh->lock);

	} else {

	} else if (time_after(jiffies, rt->last_probe +

				       idev->cnf.rtr_probe_interval)) {

		work = kmalloc(sizeof(*work), GFP_ATOMIC);

	}



	if (work) {

		rt->last_probe = jiffies;

		INIT_WORK(&work->work, rt6_probe_deferred);

		work->target = *nh_gw;

		dev_hold(dev);

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