From: Russell Strong <russell@strong.id.au>
To: Stephen Hemminger <stephen@networkplumber.org>
Cc: netdev@vger.kernel.org
Subject: Re: vxlan mac address generation
Date: Wed, 15 Apr 2020 17:28:00 +1000 [thread overview]
Message-ID: <20200415172800.50a3acc7@strong.id.au> (raw)
In-Reply-To: <20200414211206.40a324b4@hermes.lan>
On Tue, 14 Apr 2020 21:12:06 -0700
Stephen Hemminger <stephen@networkplumber.org> wrote:
> On Wed, 15 Apr 2020 10:05:24 +1000
> Russell Strong <russell@strong.id.au> wrote:
>
> > Hi Stephen,
> >
> > I've hit a problem with vxlan not communicating because mac
> > addresses being duplicated when I use the same IFNAME across
> > multiple virtual machines. The mac address appears to be some sort
> > of hash related to the IFNAME. Changing the name changes the mac
> > address.
> >
> > Looking at vxlan_setup this should be random (eth_hw_addr_random)
> > but it is not.
> >
> > Is there a bug here?
> >
> > Regards,
> > Russell Strong
>
> I don't know what platform you are using but on x86-64 Debian 10.
>
> # ip li add vxlan0 type vxlan id 1
> vxlan: destination port not specified
> Will use Linux kernel default (non-standard value)
> Use 'dstport 4789' to get the IANA assigned value
> Use 'dstport 0' to get default and quiet this message
> # ip li show dev vxlan0
> 8: vxlan0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode
> DEFAULT group default qlen 1000 link/ether 5a:09:e2:81:08:61 brd
> ff:ff:ff:ff:ff:ff # ip li del dev vxlan0
> # ip li add vxlan0 type vxlan id 1
> vxlan: destination port not specified
> Will use Linux kernel default (non-standard value)
> Use 'dstport 4789' to get the IANA assigned value
> Use 'dstport 0' to get default and quiet this message
> # ip li show dev vxlan0
> 9: vxlan0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode
> DEFAULT group default qlen 1000 link/ether 06:8d:c0:4a:73:90 brd
> ff:ff:ff:ff:ff:ff # ip li del dev vxlan0
>
>
> # ip li add vxlan0 type vxlan id 1
> vxlan: destination port not specified
> Will use Linux kernel default (non-standard value)
> Use 'dstport 4789' to get the IANA assigned value
> Use 'dstport 0' to get default and quiet this message
> # ip li show dev vxlan0
> 11: vxlan0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode
> DEFAULT group default qlen 1000 link/ether a2:2e:04:f6:85:73 brd
> ff:ff:ff:ff:ff:ff
>
I tried debian ( 4.19.0-8-amd64 ) and got the same result as you. I am
using Fedora 31 ( 5.5.15-200.fc31.x86_64 ). I have discovered a
difference:
On fedora /sys/class/net/v0/addr_assign_type = 3
On debian /sys/class/net/v0/addr_assign_type = 1
The debian value is what I would expect (NET_ADDR_RANDOM). I thought
addr_assign_type was controlled by the driver. Do you think this could
be a Fedora bug, or perhaps something has changed between 4.19 and 5.5?
next prev parent reply other threads:[~2020-04-15 7:28 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20200415100524.1ed7f9f9@strong.id.au>
[not found] ` <20200414172348.365896e5@hermes.lan>
2020-04-15 1:38 ` vxlan mac address generation Russell Strong
[not found] ` <20200414211206.40a324b4@hermes.lan>
2020-04-15 7:28 ` Russell Strong [this message]
2020-04-15 10:21 ` Ido Schimmel
2020-04-15 23:53 ` Russell Strong
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