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Commit f5bbe7ee authored by Wei Wang's avatar Wei Wang Committed by David S. Miller
Browse files

ipv6: prepare rt6_mtu_change() for exception table 



If we move all cached dst into the exception table under the main route,
current rt6_mtu_change() will no longer be able to access them.
This commit makes rt6_mtu_change_route() function to also go through all
cached routes in the exception table under the main route and do proper
updates on the mtu.
This is a preparation in order to move all cached routes into the
exception table.

Signed-off-by: default avatarWei Wang <weiwan@google.com>
Signed-off-by: default avatarMartin KaFai Lau <kafai@fb.com>
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 60006a48

net/ipv6/route.c

+40 −0
Original line number Diff line number Diff line
@@ -1269,6 +1269,14 @@ static int rt6_insert_exception(struct rt6_info *nrt, 
	 * in rt6_remove_prefsrc()

	 */

	nrt->rt6i_prefsrc = ort->rt6i_prefsrc;

	/* rt6_mtu_change() might lower mtu on ort.

	 * Only insert this exception route if its mtu

	 * is less than ort's mtu value.

	 */

	if (nrt->rt6i_pmtu >= dst_mtu(&ort->dst)) {

		err = -EINVAL;

		goto out;

	}



	rt6_ex = __rt6_find_exception_spinlock(&bucket, &nrt->rt6i_dst.addr,

					       src_key);
@@ -1457,6 +1465,32 @@ static void rt6_exceptions_remove_prefsrc(struct rt6_info *rt) 
	}

}



static void rt6_exceptions_update_pmtu(struct rt6_info *rt, int mtu)

{

	struct rt6_exception_bucket *bucket;

	struct rt6_exception *rt6_ex;

	int i;



	bucket = rcu_dereference_protected(rt->rt6i_exception_bucket,

					lockdep_is_held(&rt6_exception_lock));



	if (bucket) {

		for (i = 0; i < FIB6_EXCEPTION_BUCKET_SIZE; i++) {

			hlist_for_each_entry(rt6_ex, &bucket->chain, hlist) {

				struct rt6_info *entry = rt6_ex->rt6i;

				/* For RTF_CACHE with rt6i_pmtu == 0

				 * (i.e. a redirected route),

				 * the metrics of its rt->dst.from has already

				 * been updated.

				 */

				if (entry->rt6i_pmtu && entry->rt6i_pmtu > mtu)

					entry->rt6i_pmtu = mtu;

			}

			bucket++;

		}

	}

}



struct rt6_info *ip6_pol_route(struct net *net, struct fib6_table *table,

			       int oif, struct flowi6 *fl6, int flags)

{
@@ -3296,6 +3330,10 @@ static int rt6_mtu_change_route(struct rt6_info *rt, void *p_arg) 
	if (rt->dst.dev == arg->dev &&

	    dst_metric_raw(&rt->dst, RTAX_MTU) &&

	    !dst_metric_locked(&rt->dst, RTAX_MTU)) {

		spin_lock_bh(&rt6_exception_lock);

		/* This case will be removed once the exception table

		 * is hooked up.

		 */

		if (rt->rt6i_flags & RTF_CACHE) {

			/* For RTF_CACHE with rt6i_pmtu == 0

			 * (i.e. a redirected route),
@@ -3309,6 +3347,8 @@ static int rt6_mtu_change_route(struct rt6_info *rt, void *p_arg) 
			    dst_mtu(&rt->dst) == idev->cnf.mtu6)) {

			dst_metric_set(&rt->dst, RTAX_MTU, arg->mtu);

		}

		rt6_exceptions_update_pmtu(rt, arg->mtu);

		spin_unlock_bh(&rt6_exception_lock);

	}

	return 0;

}