From: Stas Sergeev <stsp@list•ru>
To: Sowmini Varadhan <sowmini.varadhan@oracle•com>
Cc: netdev <netdev@vger•kernel.org>
Subject: Re: Q: bad routing table cache entries
Date: Mon, 4 Jan 2016 04:32:49 +0300 [thread overview]
Message-ID: <5689CBC1.7030402@list.ru> (raw)
In-Reply-To: <20160104010539.GC9087@oracle.com>
04.01.2016 04:05, Sowmini Varadhan пишет:
> On (12/30/15 15:42), Stas Sergeev wrote:
>> 29.12.2015 18:22, Sowmini Varadhan пишет:
>>> Do you have admin control over the ubuntu router?
>>> If yes, you might want to check the shared_media [#] setting
>>> on that router for the interfaces with overlapping subnets.
>>> (it is on by default, I would try turning it off).
>> That didn't help, problem re-appears.
> the code that sets things up for redirect is this:
>
> if (out_dev == in_dev && err && IN_DEV_TX_REDIRECTS(out_dev) &&
> skb->protocol == htons(ETH_P_IP) &&
> (IN_DEV_SHARED_MEDIA(out_dev) ||
> inet_addr_onlink(out_dev, saddr, FIB_RES_GW(*res))))
> IPCB(skb)->flags |= IPSKB_DOREDIRECT;
>
> If you are still seeing the problematic redirect after disabling
> shared_media, then you would need to trace through inet_addr_onlink()
> to see why it was not returning false. As I said before, afaict from
> reading the code, inet_addr_onlink looks right. So there may be something
> unusual with your netmask config on in_dev/out_dev.
OK, thanks for the hint. Looks like a small function, I'll
trace it with systemtap a week later.
But I am more worrying about accepting such a redirects.
Almost certainly a bug.
> But even if the redirect is suppressed, sounds like the network/netmask
> config is sub-optimal, since each packet gets (needlessly?) sent
> up/down the router's in_dev/out_dev. That should be avoided, if possible.
Since I don't have a root access to the 192.168.0.1, I can't change
the masks. But curing the 192.168.8.1 router would give enough
of a relief too.
next prev parent reply other threads:[~2016-01-04 1:23 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-29 10:54 Q: bad routing table cache entries Stas Sergeev
2015-12-29 11:58 ` Sowmini Varadhan
2015-12-29 12:06 ` Stas Sergeev
2015-12-29 12:32 ` Sowmini Varadhan
2015-12-29 12:43 ` Stas Sergeev
2015-12-29 13:19 ` Stas Sergeev
2015-12-29 15:22 ` Sowmini Varadhan
2015-12-29 15:38 ` Stas Sergeev
2015-12-29 17:40 ` Stas Sergeev
2015-12-30 12:42 ` Stas Sergeev
2015-12-30 14:17 ` Eric Dumazet
2015-12-30 17:56 ` David Miller
2016-01-04 1:05 ` Sowmini Varadhan
2016-01-04 1:32 ` Stas Sergeev [this message]
2016-01-04 17:23 ` Stas Sergeev
2016-01-12 14:40 ` Stas Sergeev
2016-01-12 14:47 ` Sowmini Varadhan
2016-01-12 20:33 ` David Miller
2016-01-12 15:34 ` Hannes Frederic Sowa
2016-01-12 15:52 ` Hannes Frederic Sowa
2016-01-12 16:03 ` Stas Sergeev
2016-01-12 16:10 ` Hannes Frederic Sowa
2016-01-12 16:42 ` Stas Sergeev
2016-01-12 16:56 ` Stas Sergeev
2016-01-12 17:06 ` Hannes Frederic Sowa
2016-01-12 17:18 ` Stas Sergeev
2016-01-12 17:26 ` Hannes Frederic Sowa
2016-01-12 17:33 ` Stas Sergeev
2016-01-12 17:47 ` Hannes Frederic Sowa
2016-01-12 20:43 ` Stas Sergeev
2016-01-12 22:26 ` Hannes Frederic Sowa
2016-01-12 22:57 ` Stas Sergeev
2016-01-12 23:07 ` Hannes Frederic Sowa
2016-01-13 12:59 ` Stas Sergeev
2016-01-12 17:41 ` Stas Sergeev
2016-01-12 15:57 ` Stas Sergeev
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