Message ID | 20131024081427.GC15744@order.stressinduktion.org |
---|---|
State | Accepted, archived |
Delegated to: | David Miller |
Headers | show |
From: Hannes Frederic Sowa <hannes@stressinduktion.org> Date: Thu, 24 Oct 2013 10:14:27 +0200 > On receiving a packet too big icmp error we update the expire value by > calling rt6_update_expires. This function uses dst_set_expires which is > implemented that it can only reduce the expiration value of the dst entry. > > If we insert new routing non-expiry information into the ipv6 fib where > we already have a matching rt6_info we only clear the RTF_EXPIRES flag > in rt6i_flags and leave the dst.expires value as is. > > When new mtu information arrives for that cached dst_entry we again > call dst_set_expires. This time it won't update the dst.expire value > because we left the dst.expire value intact from the last update. So > dst_set_expires won't touch dst.expires. > > Fix this by resetting dst.expires when clearing the RTF_EXPIRE flag. > dst_set_expires checks for a zero expiration and updates the > dst.expires. > > In the past this (not updating dst.expires) was necessary because > dst.expire was placed in a union with the dst_entry *from reference > and rt6_clean_expires did assign NULL to it. This split happend in > ecd9883724b78cc72ed92c98bcb1a46c764fff21 ("ipv6: fix race condition > regarding dst->expires and dst->from"). > > Reported-by: Steinar H. Gunderson <sgunderson@bigfoot.com> > Reported-by: Valentijn Sessink <valentyn@blub.net> > Cc: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> > Acked-by: Eric Dumazet <edumazet@google.com> > Tested-by: Valentijn Sessink <valentyn@blub.net> > Signed-off-by: Hannes Frederic Sowa <hannes@stressinduktion.org> Applied. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/include/net/ip6_fib.h b/include/net/ip6_fib.h index 48ec25a..5e661a9 100644 --- a/include/net/ip6_fib.h +++ b/include/net/ip6_fib.h @@ -165,6 +165,7 @@ static inline struct inet6_dev *ip6_dst_idev(struct dst_entry *dst) static inline void rt6_clean_expires(struct rt6_info *rt) { rt->rt6i_flags &= ~RTF_EXPIRES; + rt->dst.expires = 0; } static inline void rt6_set_expires(struct rt6_info *rt, unsigned long expires)