From: Guillaume Nault <gnault@redhat.com>
To: Hangbin Liu <liuhangbin@gmail.com>
Cc: netdev@vger.kernel.org, Julian Anastasov <ja@ssi.bg>,
Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>,
David Ahern <dsahern@gmail.com>,
Eric Dumazet <edumazet@google.com>,
David Miller <davem@davemloft.net>,
Pablo Neira <pablo@netfilter.org>,
Stephen Hemminger <stephen@networkplumber.org>,
Alexey Kodanev <alexey.kodanev@oracle.com>
Subject: Re: [PATCH net-next 5/8] tunnel: do not confirm neighbor when do pmtu update
Date: Thu, 19 Dec 2019 18:47:20 +0100 [thread overview]
Message-ID: <20191219174720.GA14566@linux.home> (raw)
In-Reply-To: <20191218115313.19352-6-liuhangbin@gmail.com>
On Wed, Dec 18, 2019 at 07:53:10PM +0800, Hangbin Liu wrote:
> When do IPv6 tunnel PMTU update and calls __ip6_rt_update_pmtu() in the end,
> we should not call dst_confirm_neigh() as there is no two-way communication.
>
> Although ipv4 tunnel is not affected as __ip_rt_update_pmtu() does not call
> dst_confirm_neigh(), we still not do neigh confirm to keep consistency with
> IPv6 code.
>
This is a bit confusing. IPv4 tunnels (e.g. gretap) are affected, as show
by your reproducer. Quoting patch 0:
"""
The reason is when we ping6 remote via gretap, we will call like
gre_tap_xmit()
- ip_tunnel_xmit()
- tnl_update_pmtu()
- skb_dst_update_pmtu()
- ip6_rt_update_pmtu()
- __ip6_rt_update_pmtu()
- dst_confirm_neigh()
- ip6_confirm_neigh()
- __ipv6_confirm_neigh()
- n->confirmed = now
"""
IPv4 is not affected if it's on the overlay, but that's not what is
this patch cares about. Unless I've misunderstood this paragraph, I
think that you can just delete it.
> Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
> ---
> net/ipv4/ip_tunnel.c | 2 +-
> net/ipv6/ip6_tunnel.c | 4 ++--
> 2 files changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/net/ipv4/ip_tunnel.c b/net/ipv4/ip_tunnel.c
> index 38c02bb62e2c..0fe2a5d3e258 100644
> --- a/net/ipv4/ip_tunnel.c
> +++ b/net/ipv4/ip_tunnel.c
> @@ -505,7 +505,7 @@ static int tnl_update_pmtu(struct net_device *dev, struct sk_buff *skb,
> mtu = skb_valid_dst(skb) ? dst_mtu(skb_dst(skb)) : dev->mtu;
>
> if (skb_valid_dst(skb))
> - skb_dst_update_pmtu(skb, mtu);
> + skb_dst_update_pmtu_no_confirm(skb, mtu);
>
Fixes: 0dec879f636f ("net: use dst_confirm_neigh for UDP, RAW, ICMP, L2TP")
next prev parent reply other threads:[~2019-12-19 17:47 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-22 6:19 [PATCH net] ipv6/route: only update neigh confirm time if pmtu changed Hangbin Liu
2019-11-22 18:04 ` David Miller
2019-11-26 9:17 ` Hangbin Liu
2019-12-03 2:11 ` [PATCHv2 net] ipv6/route: should not update neigh confirm time during PMTU update Hangbin Liu
2019-12-03 2:47 ` David Miller
2019-12-03 10:15 ` Hangbin Liu
2019-12-03 10:25 ` Hangbin Liu
2019-12-03 19:58 ` David Miller
2019-12-10 3:36 ` Hangbin Liu
2019-12-10 17:00 ` Guillaume Nault
2019-12-18 11:53 ` [PATCH net-next 0/8] disable neigh update for tunnels during pmtu update Hangbin Liu
2019-12-18 11:53 ` [PATCH net-next 1/8] net: add bool confirm_neigh parameter for dst_ops.update_pmtu Hangbin Liu
2019-12-18 11:53 ` [PATCH net-next 2/8] ip6_gre: do not confirm neighbor when do pmtu update Hangbin Liu
2019-12-18 11:53 ` [PATCH net-next 3/8] gtp: " Hangbin Liu
2019-12-18 11:53 ` [PATCH net-next 4/8] net/dst: add new function skb_dst_update_pmtu_no_confirm Hangbin Liu
2019-12-18 11:53 ` [PATCH net-next 5/8] tunnel: do not confirm neighbor when do pmtu update Hangbin Liu
2019-12-19 17:47 ` Guillaume Nault [this message]
2019-12-20 2:36 ` Hangbin Liu
2019-12-18 11:53 ` [PATCH net-next 6/8] vti: " Hangbin Liu
2019-12-18 11:53 ` [PATCH net-next 7/8] sit: " Hangbin Liu
2019-12-18 11:53 ` [PATCH net-next 8/8] net/dst: do not confirm neighbor for vxlan and geneve " Hangbin Liu
2019-12-19 17:49 ` Guillaume Nault
2019-12-18 12:01 ` [PATCH net-next 0/8] disable neigh update for tunnels during " Hangbin Liu
2019-12-19 17:57 ` Guillaume Nault
2019-12-20 2:48 ` Hangbin Liu
2019-12-19 17:53 ` Guillaume Nault
2019-12-20 3:25 ` [PATCHv4 net " Hangbin Liu
2019-12-20 3:25 ` [PATCHv4 net 1/8] net: add bool confirm_neigh parameter for dst_ops.update_pmtu Hangbin Liu
2019-12-20 3:25 ` [PATCHv4 net 2/8] ip6_gre: do not confirm neighbor when do pmtu update Hangbin Liu
2019-12-20 3:25 ` [PATCHv4 net 3/8] gtp: " Hangbin Liu
2019-12-21 18:35 ` Guillaume Nault
2019-12-20 3:25 ` [PATCHv4 net 4/8] net/dst: add new function skb_dst_update_pmtu_no_confirm Hangbin Liu
2019-12-20 3:25 ` [PATCHv4 net 5/8] tunnel: do not confirm neighbor when do pmtu update Hangbin Liu
2019-12-21 18:43 ` Guillaume Nault
2019-12-20 3:25 ` [PATCHv4 net 6/8] vti: " Hangbin Liu
2019-12-21 18:30 ` Guillaume Nault
2019-12-20 3:25 ` [PATCHv4 net 7/8] sit: " Hangbin Liu
2019-12-20 3:25 ` [PATCHv4 net 8/8] net/dst: do not confirm neighbor for vxlan and geneve " Hangbin Liu
2019-12-21 18:38 ` Guillaume Nault
2019-12-20 16:14 ` [PATCHv4 net 0/8] disable neigh update for tunnels during " David Ahern
2019-12-22 2:51 ` [PATCHv5 " Hangbin Liu
2019-12-22 2:51 ` [PATCHv5 net 1/8] net: add bool confirm_neigh parameter for dst_ops.update_pmtu Hangbin Liu
2019-12-22 2:51 ` [PATCHv5 net 2/8] ip6_gre: do not confirm neighbor when do pmtu update Hangbin Liu
2019-12-22 2:51 ` [PATCHv5 net 3/8] gtp: " Hangbin Liu
2019-12-22 2:51 ` [PATCHv5 net 4/8] net/dst: add new function skb_dst_update_pmtu_no_confirm Hangbin Liu
2019-12-22 2:51 ` [PATCHv5 net 5/8] tunnel: do not confirm neighbor when do pmtu update Hangbin Liu
2019-12-22 2:51 ` [PATCHv5 net 6/8] vti: " Hangbin Liu
2019-12-22 2:51 ` [PATCHv5 net 7/8] sit: " Hangbin Liu
2019-12-22 2:51 ` [PATCHv5 net 8/8] net/dst: do not confirm neighbor for vxlan and geneve " Hangbin Liu
2019-12-22 22:10 ` [PATCHv5 net 0/8] disable neigh update for tunnels during " Guillaume Nault
2019-12-25 6:30 ` David Miller
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