Skip site navigation (1)Skip section navigation (2)
Date:      Sun, 18 May 2025 21:30:55 +0100
From:      Jessica Clarke <jrtc27@freebsd.org>
To:        Mark Johnston <markj@freebsd.org>
Cc:        Mitchell Horne <mhorne@freebsd.org>, Lexi Winter <ivy@freebsd.org>, "src-committers@freebsd.org" <src-committers@freebsd.org>, "dev-commits-src-all@freebsd.org" <dev-commits-src-all@freebsd.org>, "dev-commits-src-main@freebsd.org" <dev-commits-src-main@freebsd.org>
Subject:   Re: git: b61850c4e6f6 - main - bridge(4): default net.link.bridge.member_ifaddrs to false
Message-ID:  <82C39393-F26D-4E7B-B62A-5CC9C85BAD1A@freebsd.org>
In-Reply-To: <aCpBp5MhoiBCSA5y@nuc>
References:  <202505150004.54F04FhR046897@gitrepo.freebsd.org> <d839f137-b43b-416b-968f-439301f0a5c6@freebsd.org> <E0215FA7-F317-48EE-954C-15B0FA0ED7F3@freebsd.org> <aCpBp5MhoiBCSA5y@nuc>

next in thread | previous in thread | raw e-mail | index | archive | help
On 18 May 2025, at 21:23, Mark Johnston <markj@freebsd.org> wrote:
> On Sun, May 18, 2025 at 07:53:14PM +0100, Jessica Clarke wrote:
>> On 17 May 2025, at 22:18, Mitchell Horne <mhorne@freebsd.org> wrote:
>>> On 5/14/25 21:04, Lexi Winter wrote:
>>>> The branch main has been updated by ivy:
>>>>=20
>>>> URL: =
https://cgit.FreeBSD.org/src/commit/?id=3Db61850c4e6f6b0f21b36da7238db969d=
9090309e
>>>>=20
>>>> commit b61850c4e6f6b0f21b36da7238db969d9090309e
>>>> Author:     Lexi Winter <ivy@FreeBSD.org>
>>>> AuthorDate: 2025-05-14 14:26:24 +0000
>>>> Commit:     Lexi Winter <ivy@FreeBSD.org>
>>>> CommitDate: 2025-05-15 00:02:52 +0000
>>>>=20
>>>>   bridge(4): default net.link.bridge.member_ifaddrs to false
>>>>=20
>>>>   As discussed on arch@, this behaviour is broken and confuses =
users, so
>>>>   disable it by default.  For 15.0-RELEASE, allow it to be =
re-enabled
>>>>   using a sysctl, but the sysctl will be removed in 16.0R.
>>>>=20
>>>=20
>>> Hi Lexi,
>>>=20
>>> I just updated my workstation past this commit. I found that my main
>>> ethernet interface didn't receive an IP address, and had to set the
>>> sysctl to proceed as before.
>>>=20
>>> I have the following network configuration lines in my rc.conf:
>>>=20
>>> ifconfig_re0=3D"DHCP"
>>> cloned_interfaces=3D"bridge0 tap0"
>>> ifconfig_bridge0=3D"addm re0 addm tap0 up"
>>=20
>> I also have a setup like this, as I suspect many do.
>=20
> I do too.
>=20
>> The handbook even
>> gives this configuration in places[1] (though note it=E2=80=99s =
inconsistent in
>> whether the interface or bridge should have the address). The lack of
>> interaction with devd to automatically run dhclient as re0 comes and
>> goes is also rather sucky, especially if re0 is wlan0. I appreciate
>> that there may well be good technical reasons why this shouldn=E2=80=99=
t be
>> what people do, but (a) it is for specifically this case and I think
>> it=E2=80=99s a bit shortsighted to go and break something we still =
document
>> today as correct (b) the UX needs improving specifically for bridging =
a
>> real interface to one or more tap ones before we enforce this.
>=20
> I agree.  Even if the setup is broken in some way, it works fine for
> simple cases and this will be a nasty surprise when upgrading.
>=20
> It would be much better IMO to print a warning and let users fix their
> configuration before flipping the default.  That is how we handled
> interface address configuration without a netmask: commit d8237b955528
> added a warning, and some time later it was turned into a fatal error.
> I really think it would be better to do something similar here.

That would go some way to helping, but I really do not want =E2=80=9CI =
want a
tap interface for a VM=E2=80=9D and =E2=80=9CI want devd+dhclient to =
manage DHCP for me
automatically=E2=80=9D to be incompatible, which based on the thread =
here it
sounds like they are. Somebody needs to fix that before we even warn
users not to do what they=E2=80=99re doing, let alone make it an error.

Especially given that SYNCDHCP is not compatible with WPA, given that
just runs wpa_supplicant as a daemon and relies on that later
triggering dhclient?

Jess




Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?82C39393-F26D-4E7B-B62A-5CC9C85BAD1A>