[ovs-dev] [PATCH v3] Replace most uses of and references to "ifconfig" by "ip".
Greg Rose
gvrose8192 at gmail.com
Wed May 31 16:29:40 UTC 2017
On Wed, 2017-05-31 at 08:32 -0700, Ben Pfaff wrote:
> On Wed, May 31, 2017 at 11:39:28AM +0200, Matthias May wrote:
> > On 27/05/17 04:29, Hunt Xu wrote:
> > > On Fri, May 26, 2017 at 11:46 PM, Ben Pfaff <blp at ovn.org> wrote:
> > >> It's becoming more common that OSes include "ip" but not "ifconfig", so
> > >> it's best to avoid using the latter. This commit removes most references
> > >> to "ifconfig" and replaces them by "ip". It also adds a build-time check
> > >> to make it harder to introduce new uses of "ifconfig".
> > >>
> > >> Signed-off-by: Ben Pfaff <blp at ovn.org>
> > >> ---
> > >
> > > <snip>
> > >
> > >> diff --git a/Documentation/faq/issues.rst b/Documentation/faq/issues.rst
> > >> index c60336a10569..82d0605da125 100644
> > >> --- a/Documentation/faq/issues.rst
> > >> +++ b/Documentation/faq/issues.rst
> > >> @@ -43,8 +43,8 @@ eth0. Help!
> > >> itself. For example, assuming that eth0's IP address is 192.168.128.5, you
> > >> could run the commands below to fix up the situation::
> > >>
> > >> - $ ifconfig eth0 0.0.0.0
> > >> - $ ifconfig br0 192.168.128.5
> > >> + $ ip addr flush dev eth0
> > >> + $ ip addr add 192.168.128.5 dev br0
> > >
> > > ip addr add 192.168.128.5/24 dev br0
> > >
> > > It seems using ifconfig without specifying any netmask the netmask/prefixlen
> > > will still be properly set (not diving quite deep, but strace indicates that
> > > this is not done by ifconfig, ifconfig don't even try to set the netmask),
> > > whlie using ip-address with only the address specified the prefixlen is
> > > always 32.
> > >
> > > Some tests on my Ubuntu 16.04:
> > > 1a. ifconfig br0 192.168.128.5 -> br0 gets 192.168.128.5/24
> > > 1b. ip addr add 192.168.128.5 dev br0 -> br0 gets 192.168.128.5/32
> > > 2a. ifconfig br0 172.16.128.5 -> br0 gets 172.16.128.5/16
> > > 2b. ip addr add 172.16.128.5 dev br0 -> br0 gets 172.16.128.5/32
> > > 3a. ifconfig br0 10.0.128.5 -> br0 gets 10.0.128.5/8
> > > 3b. ip addr add 10.0.128.5 dev br0 -> br0 gets 10.0.128.5/32
> > >
> > >>
> > *snip*
> >
> > You might want to consider to add brd + to the ip command.
> > E.g. ip addr add 192.168.128.5/24 brd + dev br0
> >
> > Without:
> > 7: br0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
> > link/ether 1a:78:fe:72:9c:be brd ff:ff:ff:ff:ff:ff
> > inet 192.168.128.5/24 scope global br0
> > valid_lft forever preferred_lft forever
> >
> > With:
> > 7: br0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
> > link/ether 1a:78:fe:72:9c:be brd ff:ff:ff:ff:ff:ff
> > inet 192.168.128.5/24 brd 192.168.128.255 scope global br0
> > valid_lft forever preferred_lft forever
> >
> > As you can see the broadcast address isn't set without.
> >
> > I see you already posted a v4 but this comment seems more appropriate in this thread.
>
> What happens if no broadcast address is specified? I've never seen
> instructions say that one should specify this, so I really wonder
> whether it is necessary.
My understanding of this is that the brd command is used to over ride
the broadcast address that would normally be computed by specifying the
IP/CIDR. I don't think it is necessary and I don't generally specify it
in normal usage.
Thanks,
- Greg
> _______________________________________________
> dev mailing list
> dev at openvswitch.org
> https://mail.openvswitch.org/mailman/listinfo/ovs-dev
More information about the dev
mailing list