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authorPaolo Abeni <pabeni@redhat.com>2017-10-19 16:07:11 +0200
committerDavid S. Miller <davem@davemloft.net>2017-10-21 01:39:10 +0100
commit1859bac04fb696b858dbbff59503c945ec871bd9 (patch)
tree50297ab528d0e1eacc1ec9f34f1698500327c263 /net/ipv6
parentb886d5f2f2906a866e33212734d204dfe35d50d9 (diff)
ipv6: remove from fib tree aged out RTF_CACHE dst
The commit 2b760fcf5cfb ("ipv6: hook up exception table to store dst cache") partially reverted the commit 1e2ea8ad37be ("ipv6: set dst.obsolete when a cached route has expired"). As a result, RTF_CACHE dst referenced outside the fib tree will not be removed until the next sernum change; dst_check() does not fail on aged-out dst, and dst->__refcnt can't decrease: the aged out dst will stay valid for a potentially unlimited time after the timeout expiration. This change explicitly removes RTF_CACHE dst from the fib tree when aged out. The rt6_remove_exception() logic will then obsolete the dst and other entities will drop the related reference on next dst_check(). pMTU exceptions are not aged-out, and are removed from the exception table only when the - usually considerably longer - ip6_rt_mtu_expires timeout expires. v1 -> v2: - do not touch dst.obsolete in rt6_remove_exception(), not needed v2 -> v3: - take care of pMTU exceptions, too Fixes: 2b760fcf5cfb ("ipv6: hook up exception table to store dst cache") Signed-off-by: Paolo Abeni <pabeni@redhat.com> Acked-by: Wei Wang <weiwan@google.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv6')
-rw-r--r--net/ipv6/route.c12
1 files changed, 11 insertions, 1 deletions
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index efecdcff5055..074fac966018 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1575,7 +1575,13 @@ static void rt6_age_examine_exception(struct rt6_exception_bucket *bucket,
{
struct rt6_info *rt = rt6_ex->rt6i;
- if (atomic_read(&rt->dst.__refcnt) == 1 &&
+ /* we are pruning and obsoleting aged-out and non gateway exceptions
+ * even if others have still references to them, so that on next
+ * dst_check() such references can be dropped.
+ * EXPIRES exceptions - e.g. pmtu-generated ones are pruned when
+ * expired, independently from their aging, as per RFC 8201 section 4
+ */
+ if (!(rt->rt6i_flags & RTF_EXPIRES) &&
time_after_eq(now, rt->dst.lastuse + gc_args->timeout)) {
RT6_TRACE("aging clone %p\n", rt);
rt6_remove_exception(bucket, rt6_ex);
@@ -1595,6 +1601,10 @@ static void rt6_age_examine_exception(struct rt6_exception_bucket *bucket,
rt6_remove_exception(bucket, rt6_ex);
return;
}
+ } else if (__rt6_check_expired(rt)) {
+ RT6_TRACE("purging expired route %p\n", rt);
+ rt6_remove_exception(bucket, rt6_ex);
+ return;
}
gc_args->more++;
}