From: Jakub Sitnicki <jkbs@redhat.com>
To: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Cc: netdev@vger.kernel.org, edumazet@google.com, davem@davemloft.net,
roopa@cumulusnetworks.com, dsa@cumulusnetworks.com
Subject: Re: [PATCH net-next v2] net: ipv4: add support for ECMP hash policy choice
Date: Wed, 08 Mar 2017 13:05:36 +0100 [thread overview]
Message-ID: <878togdldb.fsf@redhat.com> (raw)
In-Reply-To: <1488884508-14016-1-git-send-email-nikolay@cumulusnetworks.com>
Hi Nikolay,
On Tue, Mar 07, 2017 at 11:01 AM GMT, Nikolay Aleksandrov wrote:
> This patch adds support for ECMP hash policy choice via a new sysctl
> called fib_multipath_hash_policy and also adds support for L4 hashes.
> The current values for fib_multipath_hash_policy are:
> 0 - layer 3 (default)
> 1 - layer 4
> If there's an skb hash already set and it matches the chosen policy then it
> will be used instead of being calculated. The ICMP inner IP addresses use
> is removed.
>
> Signed-off-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
> ---
> v2:
> - removed the output_key_hash as it's not needed anymore
> - reverted to my original/internal patch with L3 as default hash
What about ICMP PTB (Fragmentation Needed) forwarding that makes PMTUD
work with ECMP in setups like described in RFC7690 [1]?
ptb -> router ecmp -> next hop L4/L7 load balancer -> destination
router --> load balancer 1 --->
\\--> load balancer 2 ---> load-balanced service
\--> load balancer N --->
Removing special treatment of ICMP errors will break it, won't it?
FWIW, I gave a run to your patch (default settings, L3 hash) with a test
script [2] that simulates such a setup and it confirmed my worries - PTB
errors don't travel back to the source host any more.
-Jakub
[1] https://tools.ietf.org/html/rfc7690#section-2
[2] https://github.com/jsitnicki/tools/commit/ccb85e68421df4ffd8b7abf00f6f5fe1c6a5af76
next prev parent reply other threads:[~2017-03-08 12:07 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-06 14:59 [PATCH net-next] net: ipv4: add support for ECMP hash policy choice Nikolay Aleksandrov
2017-03-06 16:24 ` David Ahern
2017-03-06 16:52 ` Nikolay Aleksandrov
2017-03-07 6:16 ` Roopa Prabhu
2017-03-07 11:01 ` [PATCH net-next v2] " Nikolay Aleksandrov
2017-03-08 12:05 ` Jakub Sitnicki [this message]
2017-03-08 12:43 ` Nikolay Aleksandrov
2017-03-08 16:00 ` Jakub Sitnicki
2017-03-13 2:23 ` David Miller
2017-03-14 15:36 ` [PATCH net-next v3] " Nikolay Aleksandrov
2017-03-14 15:55 ` Stephen Hemminger
2017-03-14 15:58 ` Nikolay Aleksandrov
2017-03-14 18:48 ` David Miller
2017-03-14 20:25 ` Stephen Hemminger
2017-03-14 21:10 ` Roopa Prabhu
2017-03-14 21:42 ` Stephen Hemminger
2017-03-14 22:38 ` Roopa Prabhu
2017-03-14 23:27 ` Stephen Hemminger
2017-03-14 23:45 ` David Ahern
2017-03-15 9:17 ` Nicolas Dichtel
2017-03-15 10:46 ` Nikolay Aleksandrov
2017-03-15 11:18 ` Nicolas Dichtel
2017-03-15 11:27 ` Nikolay Aleksandrov
2017-03-15 15:01 ` David Ahern
2017-03-15 15:20 ` Stephen Hemminger
2017-03-15 0:24 ` David Miller
2017-03-15 2:30 ` Tom Herbert
2017-03-17 3:36 ` David Miller
2017-03-14 18:55 ` Nikolay Aleksandrov
2017-03-15 11:32 ` Jakub Sitnicki
2017-03-15 12:10 ` Nikolay Aleksandrov
2017-03-16 13:28 ` [PATCH net-next v4] " Nikolay Aleksandrov
2017-03-16 16:41 ` Stephen Hemminger
2017-03-16 16:49 ` Nikolay Aleksandrov
2017-03-17 10:06 ` Nikolay Aleksandrov
2017-03-21 22:28 ` David Miller
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