diff options
| author | Maciej Żenczykowski <maze@google.com> | 2020-05-05 11:57:23 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-05-20 08:20:09 +0200 |
| commit | f152793058b557b24a5429b4cc98b2e49ef59222 (patch) | |
| tree | 9849c57a15e4ee6043b175b8c5714d59da9a51b6 /net/ipv6 | |
| parent | 5f93b45fa58c08e7b04cb0568016a15bd7d31629 (diff) | |
Revert "ipv6: add mtu lock check in __ip6_rt_update_pmtu"
[ Upstream commit 09454fd0a4ce23cb3d8af65066c91a1bf27120dd ]
This reverts commit 19bda36c4299ce3d7e5bce10bebe01764a655a6d:
| ipv6: add mtu lock check in __ip6_rt_update_pmtu
|
| Prior to this patch, ipv6 didn't do mtu lock check in ip6_update_pmtu.
| It leaded to that mtu lock doesn't really work when receiving the pkt
| of ICMPV6_PKT_TOOBIG.
|
| This patch is to add mtu lock check in __ip6_rt_update_pmtu just as ipv4
| did in __ip_rt_update_pmtu.
The above reasoning is incorrect. IPv6 *requires* icmp based pmtu to work.
There's already a comment to this effect elsewhere in the kernel:
$ git grep -p -B1 -A3 'RTAX_MTU lock'
net/ipv6/route.c=4813=
static int rt6_mtu_change_route(struct fib6_info *f6i, void *p_arg)
...
/* In IPv6 pmtu discovery is not optional,
so that RTAX_MTU lock cannot disable it.
We still use this lock to block changes
caused by addrconf/ndisc.
*/
This reverts to the pre-4.9 behaviour.
Cc: Eric Dumazet <edumazet@google.com>
Cc: Willem de Bruijn <willemb@google.com>
Cc: Xin Long <lucien.xin@gmail.com>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Fixes: 19bda36c4299 ("ipv6: add mtu lock check in __ip6_rt_update_pmtu")
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net/ipv6')
| -rw-r--r-- | net/ipv6/route.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/net/ipv6/route.c b/net/ipv6/route.c index c81d8e9e5169..3b4af0a8bca6 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -2728,8 +2728,10 @@ static void __ip6_rt_update_pmtu(struct dst_entry *dst, const struct sock *sk, const struct in6_addr *daddr, *saddr; struct rt6_info *rt6 = (struct rt6_info *)dst; - if (dst_metric_locked(dst, RTAX_MTU)) - return; + /* Note: do *NOT* check dst_metric_locked(dst, RTAX_MTU) + * IPv6 pmtu discovery isn't optional, so 'mtu lock' cannot disable it. + * [see also comment in rt6_mtu_change_route()] + */ if (iph) { daddr = &iph->daddr; |