From: Wei Wang <wei...@google.com>
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: Wei Wang <wei...@google.com>
Signed-off-by: Martin KaFai Lau <ka...@fb.com>
Signed-off-by: Eric Dumazet <eduma...@google.com>
---
net/ipv6/route.c | 40 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 40 insertions(+)
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index f52ac57dcc99..d9805a857809 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -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;
}
--
2.14.2.920.gcf0c67979c-goog
