From: Steffen Klassert <steffen.klassert@secunet•com>
To: shengyong <shengyong1@huawei•com>
Cc: <davem@davemloft•net>, <netdev@vger•kernel.org>,
<yangyingliang@huawei•com>, <hannes@redhat•com>
Subject: Re: Question: should local address be expired when updating PMTU?
Date: Tue, 3 Feb 2015 13:01:41 +0100 [thread overview]
Message-ID: <20150203120140.GU13046@secunet.com> (raw)
In-Reply-To: <54D0A8DB.4010106@huawei.com>
On Tue, Feb 03, 2015 at 06:54:19PM +0800, shengyong wrote:
>
>
> 在 2015/2/3 17:28, Steffen Klassert 写道:
> > On Mon, Feb 02, 2015 at 04:20:24PM +0800, shengyong wrote:
> >
> > We first need to find out why you receive this Packet Too Big message,
> The packet is sent by a commercial-off-the-shelf testcase, and I can reproduce the
> situation by using scapy and creating a packet as the following:
>
> $ cat packet-too-big.py
> #!/usr/bin/python
>
> from scapy.all import *
>
> # fe80::800:27ff:fe00:0 is linklocal addr of PC
> # fe80::a00:27ff:fe1a:e2a0 is linklocal addr of VM
> base=IPv6(src='fe80::800:27ff:fe00:0',dst='fe80::a00:27ff:fe1a:e2a0')
> pkt_too_big=ICMPv6PacketTooBig(mtu=1024)
> ext_base=IPv6(src='fe80::a00:27ff:fe1a:e2a0',dst='fe80::a00:27ff:fe1a:e2a0',plen=24)
> ext_nd_na=ICMPv6ND_NA()
>
> packet=base/pkt_too_big/ext_base/ext_nd_na
> send(packet)
So it is not a valid pmtu update, this make life easier.
Can you please test the patch below (compile tested only)?
This should fix your problem, and in combination with the two patches I sent
out last week, it should cure the whole 'expiring of uncached routes' problem.
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 49596535..4ccfb9c 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -1156,7 +1156,8 @@ static void ip6_rt_update_pmtu(struct dst_entry *dst, struct sock *sk,
struct rt6_info *rt6 = (struct rt6_info *)dst;
dst_confirm(dst);
- if (mtu < dst_mtu(dst) && rt6->rt6i_dst.plen == 128) {
+ if (mtu < dst_mtu(dst) && rt6->rt6i_dst.plen == 128 &&
+ (rt6->rt6i_flags & RTF_CACHE)) {
struct net *net = dev_net(dst->dev);
rt6->rt6i_flags |= RTF_MODIFIED;
next prev parent reply other threads:[~2015-02-03 12:01 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-02-02 8:20 Question: should local address be expired when updating PMTU? shengyong
2015-02-02 21:31 ` David Miller
2015-02-03 0:52 ` Alex Gartrell
2015-02-03 1:28 ` shengyong
2015-02-03 2:10 ` Calvin Owens
2015-02-03 3:21 ` shengyong
2015-02-03 9:28 ` Steffen Klassert
2015-02-03 10:54 ` shengyong
2015-02-03 12:01 ` Steffen Klassert [this message]
2015-02-04 1:59 ` shengyong
2015-02-05 7:21 ` Steffen Klassert
2015-02-27 2:37 ` shengyong
2015-02-27 10:32 ` Steffen Klassert
2015-03-30 10:32 ` Steffen Klassert
2015-03-30 10:33 ` [PATCH RFC 1/3] ipv6: Fix after pmtu events dissapearing host routes Steffen Klassert
2015-03-30 11:15 ` Sheng Yong
2015-03-30 18:24 ` Martin Lau
2015-04-01 8:09 ` Steffen Klassert
2015-03-30 10:33 ` [PATCH RFC 2/3] ipv6: Extend the route lookups to low priority metrics Steffen Klassert
2015-03-30 10:34 ` [PATCH RFC 3/3] ipv6: Don't update pmtu on uncached routes Steffen Klassert
2015-03-30 11:13 ` Question: should local address be expired when updating PMTU? Sheng Yong
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