From: Tonghao Zhang <xiangxia.m.yue@gmail.com>
To: David Miller <davem@davemloft.net>
Cc: Linux Kernel Network Developers <netdev@vger.kernel.org>
Subject: Re: [PATCH] net: vxlan: disallow removing to other namespace
Date: Tue, 21 May 2019 13:53:04 +0800 [thread overview]
Message-ID: <CAMDZJNWpv89beaNvVvycJ5YqwcKYiFNuP_gYKz_QmsQ2roiRGw@mail.gmail.com> (raw)
In-Reply-To: <20190520.195319.201742803310676769.davem@davemloft.net>
On Tue, May 21, 2019 at 7:53 AM David Miller <davem@davemloft.net> wrote:
>
> From: xiangxia.m.yue@gmail.com
> Date: Fri, 17 May 2019 19:42:23 -0700
>
> > From: Tonghao Zhang <xiangxia.m.yue@gmail.com>
> >
> > Don't allow to remove the vxlan device to other namesapce,
> > because we maintain the data of vxlan net device on original
> > net-namespace.
> >
> > $ ip netns add ns100
> > $ ip link add vxlan100 type vxlan dstport 4789 external
> > $ ip link set dev vxlan100 netns ns100
> > $ ip netns exec ns100 ip link add vxlan200 type vxlan dstport 4789 external
> > $ ip netns exec ns100 ip link
> > ...
> > vxlan200: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
> > vxlan100: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000
> >
> > And we should create it on new net-namespace, so disallow removing it.
> >
> > Signed-off-by: Tonghao Zhang <xiangxia.m.yue@gmail.com>
>
> I don't understand this change at all.
>
> You keep saying "Remove" but I think you might mean simply "Move" because
> the NETNS_LOCAL flag prevents moving not removing.
Yes, should change "remove" to "move".
> And why is it bad to allow vxlan devices to be moved between network
> namespaces? What problem would it cause and can you guarantee that
> you are not breaking an existing user?
The problem is that we create one vxlan netdevice(e.g dstport 4789 and
external), and move it to
one net-namespace, and then we hope create one again(dstport 4789 and
external) and move it to other net-namespace, but we can't create it.
$ ip netns add ns100
$ ip link add vxlan100 type vxlan dstport 4789 external
$ ip link set dev vxlan100 netns ns100
$ ip link add vxlan200 type vxlan dstport 4789 external
RTNETLINK answers: File exists
The better way is that we should create directly it in the
net-namespace. To avoid confuse user, disallow moving it to other
net-namespace.
> I'm not applying this as-is.
next prev parent reply other threads:[~2019-05-21 5:53 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-18 2:42 [PATCH] net: vxlan: disallow removing to other namespace xiangxia.m.yue
2019-05-20 23:53 ` David Miller
2019-05-21 5:53 ` Tonghao Zhang [this message]
2019-05-21 9:28 ` Nicolas Dichtel
2019-05-21 11:08 ` Tonghao Zhang
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