[PATCH] Adding support for reloading configuration via systemd

[Jason A. Donenfeld]

On Tue, Jul 28, 2020 at 11:54 AM Tore Anderson <tore at fud.no> wrote:
>
> * Jason A. Donenfeld
>
> > On Mon, Jul 27, 2020 at 10:04 PM Tore Anderson <tore at fud.no> wrote:
> > > Absolutely, a 'wg syncconf' wrapper is unable to fully implement every
> > > conceivable change to the wg-quick config file. That said, 99.9% of my
> > > configuration changes are additions/removal of [Peer] sections that 'wg
> > > syncconf' do handle perfectly. Being able to add and remove individual
> > > VPN users without disrupting the traffic of other unrelated users is a
> > > really big win for me. I would imagine this to ability be highly
> > > desirable for most other VPN server operators as well – even for those
> > > that do not use systemd.
> >
> > But for people shell scripting, can't they just use `wg syncconf
> > wgnet0 <(wg-quick strip wgnet0)`, so that it's explicit what's
> > happening?
>
> Of course they can, just as they can opt to not use wg-quick at all.
>
> However, it would be better, in my opinion, if every user do not have
> to re-invent the wheel in order to accomplish common tasks, which (I
> assume) is the reason why wg-quick – «an extremely simple script for
> easily bringing up a WireGuard interface, suitable for a few common use
> cases», to quote its manual page – exists in the first place.
>
> > I'm still pretty hesitant for the reasons I outlined in the previous
> > email. If anything, it'd probably have to be "syncpeers", but even
> > then, it wouldn't update the routing information that wg-quick(8)
> > sometimes does.
>
> Fair enough. If you do not want it in wg-quick, I won't insist.
>
> > The right thing to do for a `wg-quick reload` command
> > would be to take into account all of the various other changes, and
> > mutate them the minimal distance to reflect the updated config file.
> > But this sounds pretty hard to do in bash. And that makes me worry
> > about overall mission creep in wg-quick(8). syncconf in wg(8) is
> > fairly simple, though still a bit verbose, but that's in C:
> > https://git.zx2c4.com/wireguard-tools/tree/src/setconf.c#n30 . And
> > there's a very clear way of doing this, whereas there are lots of
> > weird edge cases when handling routing.
>
> Agreed, this sounds very complex and not worth the trouble.
>
> That said, I do believe that most admins would not be bothered by the
> fact that some changes would require a restart (i.e., an wg-quick
> up/down cycle). This limitation is common in other pieces of software
> too, e.g., one can normally not use 'apachectl graceful' to make Apache
> listen on a new port below 1024. However, in spite of it not being
> perfect, 'apachectl graceful' remains extremely useful.
>
> > Plus, how hard is it to add `wg syncconf wgnet0 <(wg-quick strip
> > wgnet0)` to scripts?
>
> Not hard - it is precisely what my patch did, after all.

By the way, I just made this change:
https://git.zx2c4.com/wireguard-tools/commit/?id=37ed947239f4b3ef161c85428d9267eb23a69d69
I had assumed it was syncconf all along, until I checked. That makes
sense; Luis added `strip` before I added `syncconf`.

Jason