From: Martin Lau <kafai@fb.com>
To: Steffen Klassert <steffen.klassert@secunet.com>
Cc: Yang Yingliang <yangyingliang@huawei.com>,
netdev <netdev@vger.kernel.org>,
Hannes Frederic Sowa <hannes@stressinduktion.org>,
"David S. Miller" <davem@davemloft.net>
Subject: Re: [PATCH RFC 1/2] ipv6: Fix after pmtu events dissapearing host routes
Date: Thu, 5 Feb 2015 15:56:29 -0800 [thread overview]
Message-ID: <20150205235628.GA1916791@devbig242.prn2.facebook.com> (raw)
In-Reply-To: <20150128121150.GN13046@secunet.com>
On Wed, Jan 28, 2015 at 01:11:51PM +0100, Steffen Klassert wrote:
> We currently don't clone host routes before we use them.
> If a pmtu event is received on such a route, it gets
> an expires value. As soon as the expiration time is
> elapsed, the route is deleted. As a result, the host
> is not reachable any more.
>
> We fix this by cloning host routes if they are gatewayed,
> i.e. if pmtu events can happen.
>
> Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
> ---
> net/ipv6/route.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/ipv6/route.c b/net/ipv6/route.c
> index c910831..3e864e7 100644
> --- a/net/ipv6/route.c
> +++ b/net/ipv6/route.c
> @@ -961,7 +961,7 @@ redo_rt6_select:
>
> if (!(rt->rt6i_flags & (RTF_NONEXTHOP | RTF_GATEWAY)))
> nrt = rt6_alloc_cow(rt, &fl6->daddr, &fl6->saddr);
> - else if (!(rt->dst.flags & DST_HOST))
> + else if (!(rt->dst.flags & DST_HOST) || (rt->rt6i_flags & RTF_GATEWAY))
> nrt = rt6_alloc_clone(rt, &fl6->daddr);
The del path may also require changes. I am thinking:
1. Create a /128 via gateway route
2. Send some traffic and RTF_CACHE rt is created
3. Delete the /128 route by ip route del. I suspect the RTF_CACHE route may be
deleted and the route added in (1) stays.
Thanks
next prev parent reply other threads:[~2015-02-05 23:57 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-27 12:58 A problem about ICMP packet-too-big message handler Yang Yingliang
2015-01-28 5:19 ` Martin Lau
2015-01-28 6:46 ` Yang Yingliang
2015-01-28 12:45 ` Eric Dumazet
2015-01-29 1:04 ` Yang Yingliang
2015-01-28 8:42 ` Hannes Frederic Sowa
2015-01-28 10:07 ` Yang Yingliang
2015-01-28 12:10 ` Steffen Klassert
2015-01-28 12:11 ` [PATCH RFC 1/2] ipv6: Fix after pmtu events dissapearing host routes Steffen Klassert
2015-01-29 10:26 ` Hannes Frederic Sowa
2015-01-29 10:44 ` Steffen Klassert
2015-02-05 23:56 ` Martin Lau [this message]
2015-02-09 10:26 ` Steffen Klassert
2015-03-09 9:00 ` Steffen Klassert
2015-01-28 12:12 ` [PATCH RFC 2/2] ipv6: Extend the route lookups to low priority metrics Steffen Klassert
2015-01-29 3:16 ` A problem about ICMP packet-too-big message handler Yang Yingliang
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