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ipv6: rate-limit probes for neighbourless routes 

When commit 270972554c ("[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 2152caea71 ("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: 2152caea71 ("ipv6: Do not depend on rt->n in rt6_probe().")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Reviewed-by: Stefano Brivio <sbrivio@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Sabrina Dubroca 2018-10-12 16:22:47 +02:00 committed by David S. Miller
parent 64bd9c8135
commit f547fac624
2 changed files with 10 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
include/net/ip6_fib.h
View File

@ -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;

12
net/ipv6/route.c
View File

@ -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);