From: "Xiao, Jiguang" <Jiguang.Xiao@windriver.com>
To: David Ahern <dsahern@kernel.org>,
"davem@davemloft.net" <davem@davemloft.net>,
"yoshfuji@linux-ipv6.org" <yoshfuji@linux-ipv6.org>,
"kuba@kernel.org" <kuba@kernel.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Cc: "Pudak, Filip" <Filip.Pudak@windriver.com>
Subject: RE: This counter "ip6InNoRoutes" does not follow the RFC4293 specification implementation
Date: Wed, 9 Mar 2022 02:16:12 +0000 [thread overview]
Message-ID: <SJ0PR11MB51209DA3F7CAAB45A609633A930A9@SJ0PR11MB5120.namprd11.prod.outlook.com> (raw)
In-Reply-To: <SJ0PR11MB5120EBCF140B940C8FF712B9933D9@SJ0PR11MB5120.namprd11.prod.outlook.com>
Hi David
To confirm whether my test method is correct, could you please briefly describe your test procedure?
Best Regards
Xiao Jiguang
-----Original Message-----
From: Xiao, Jiguang
Sent: 2022年2月24日 17:04
To: David Ahern <dsahern@kernel.org>; davem@davemloft.net; yoshfuji@linux-ipv6.org; kuba@kernel.org; netdev@vger.kernel.org; linux-kernel@vger.kernel.org
Cc: Pudak, Filip <Filip.Pudak@windriver.com>
Subject: RE: This counter "ip6InNoRoutes" does not follow the RFC4293 specification implementation
Hi David
Thanks for guiding me how to proceed. I have captured the output result of perf (perf_output_5.10.49).
To confirm the problem, I tested it again on Ubuntu (kernel version is 5.4.0-79) using Docker and the results were the same, the only difference is the kernel version. I also collected the perf results and added them to the attachment (perf_output_5.4.0).
Best Regards
Xiao Jiguang
-----Original Message-----
From: David Ahern <dsahern@kernel.org>
Sent: 2022年2月17日 11:00
To: Xiao, Jiguang <Jiguang.Xiao@windriver.com>; davem@davemloft.net; yoshfuji@linux-ipv6.org; kuba@kernel.org; netdev@vger.kernel.org; linux-kernel@vger.kernel.org
Subject: Re: This counter "ip6InNoRoutes" does not follow the RFC4293 specification implementation
[Please note: This e-mail is from an EXTERNAL e-mail address]
On 2/16/22 3:36 AM, Xiao, Jiguang wrote:
> Hello,
>
> I found a counter in the kernel(5.10.49) that did not follow the
> RFC4293 specification. The test steps are as follows:
>
>
>
> Topology:
>
> |VM 1| ------ |linux| ------ |VM 2|
>
>
>
> Steps:
>
> 1. Verify that “VM1” is reachable from “VM 2” and vice versa using
> ping6 command.
>
> 2. On “linux” node, in proper fib, remove default route to NW address
> which “VM 2” resides in. This way, the packet won’t be forwarded by
> “linux” due to no route pointing to destination address of “VM 2”.
>
> 3. Collect the corresponding SNMP counters from “linux” node.
>
> 4. Verify that there is no connectivity from “VM 1” to “VM 2” using
> ping6 command.
>
> 5. Check the counters again.
>
>
>
> The test results:
>
> The counter “ip6InNoRoutes” in “/proc/net/dev_snmp6/” has not
> increased accordingly. In my test environment, it was always zero.
>
>
>
> My question is :
>
> Within RFC4293, “ipSystemStatsInNoRoutes” is defined as follows:
>
> “The number of input IP datagrams discarded because no route could
> be found to transmit them to their destination.”
>
> Does this version of the kernel comply with the RFC4293 specification?
>
>
I see that counter incrementing. Look at the fib6 tracepoints and see what the lookups are returning:
perf record -e fib6:* -a
<run test>
Ctrl-C
perf script
next prev parent reply other threads:[~2022-03-09 2:17 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <SJ0PR11MB51207CBDB5145A89B8A0A15393359@SJ0PR11MB5120.namprd11.prod.outlook.com>
[not found] ` <SJ0PR11MB51202FA2365341740048A64593359@SJ0PR11MB5120.namprd11.prod.outlook.com>
[not found] ` <SJ0PR11MB51209200786235187572EE0D93359@SJ0PR11MB5120.namprd11.prod.outlook.com>
[not found] ` <SJ0PR11MB5120426D474963E08936DD2493359@SJ0PR11MB5120.namprd11.prod.outlook.com>
2022-02-17 2:59 ` This counter "ip6InNoRoutes" does not follow the RFC4293 specification implementation David Ahern
2022-02-24 9:04 ` Xiao, Jiguang
2022-03-09 2:16 ` Xiao, Jiguang [this message]
2022-03-09 4:50 ` David Ahern
2022-03-31 9:13 ` Pudak, Filip
2022-03-31 14:13 ` David Ahern
2022-04-04 7:09 ` Pudak, Filip
2022-04-04 15:09 ` David Ahern
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