Re: Wireguard

[Maxime Devos <maximedevos@telenet.be>]

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crodges schreef op wo 22-09-2021 om 09:03 [-0700]:
> On Wednesday, September 1, 2021 12:07:43 A.M. PDT Maxime Devos wrote:
> > crodges schreef op zo 29-08-2021 om 14:53 [-0700]:
> > > Hello everyone,
> > > 
> > > Let me start thanking you for developing such a interesting project in GNU
> > > Guix. Also, I don't want to take up anyone's time, so you can just point
> > > to
> > > documentation or other resource succinctly and I'll do my best. I'm
> > > writing
> > > here because I tried the help list but not answer so far, after a few
> > > days.
> > > 
> > > I managed to configure wireguard on a vps running guix and created clients
> > > for my desktop and cellphone. What I want to do (and did already in a
> > > Debian vps) is to make wireguard's lan accessible to anyone connected and
> > > also browse the internet using this vpn.
> > 
> > The Wireguard service as defined in Guix System doesn't currently support
> > the forwarding you appear to describe ...
> > 
> > > As I remember, I need to allow ip forwarding using
> > > 
> > > sysctl net.ipv4.ip_forward=1
> > > 
> > > and I also need to put these rules into wireguard (the server) under
> > > [interface],
> > > 
> > > PostUp = iptables -A FORWARD -i wg0 -j ACCEPT; iptables -t nat -A
> > > POSTROUTING -o eth0 -j MASQUERADE; ip6tables -A FORWARD -i wg0 -j ACCEPT;
> > > ip6tables -t nat -A POSTROUTING -o eth0 -j MASQUERADE
> > > 
> > > PostDown = iptables -D FORWARD -i wg0 -j ACCEPT; iptables -t nat -D
> > > POSTROUTING -o eth0 -j MASQUERADE; ip6tables -D FORWARD -i wg0 -j ACCEPT;
> > > ip6tables -t nat -D POSTROUTING -o eth0 -j MASQUERADE
> > 
> > However, I don't see why this couldn't be implemented in Guix System
> > (after some changes to wireguard-service-type).
> > 
> > > Problem is, looking at the latest guix manual, PostUp and PostDown doesn't
> > > seem to exist yet. Do they exist but are still undocumented?
> > 
> > Guix uses "wg-quick", so it would seem they do exist, but are inaccessible
> > from Guix.  The configuration file is created in
> > wireguard-configuration-file (in gnu/services/vpn.scm), maybe you can
> > modify that.
> > 
> > > If they don't exist, where should be a reasonable place to add this
> > > configurations?
> > 
> > <wireguard-configuration> and wireguard-configuration-file in (gnu services
> > vpn) it would seem.  Also, sysctl-service-type would need to be extended
> > (in the ‘service-extension’ meaning of the word) to set net.ipv4.ip_forward
> > appropriately.
> > 
> > > I'm trying to do everything the guix way, when I finish this
> > > machine configuration, I'd like it to be fully replicable.
> > > 
> > > Also, is this something that I could solve modifying the wireguard service
> > > definition itself?
> > 
> > If replicability is all you need, you could add ‘postdown’ and ‘postup’
> > options to <wireguard-configuration>, which would need to be set to the
> > commands above.  However, these strings seem rather complicated for the
> > uninitiated, so I'd recommend something more high-level instead.  Some
> > interface like
> > 
> >   (wireguard-configuration
> >     [...]
> >     (addresses ...)
> >     (peers ...)
> >     (forward? #t))
> > 
> > perhaps?  Make sure to add some documentation to ‘Wireguard’ in (guix)VPN
> > Services. (Maybe add some example situations on how forward? can be used
> > and how it functions.)
> > 
> > I want to note that I don't understand what exactly you're doing, I only
> > understand that there is some forwarding going on, and I'm not unfamiliar
> > with networking issue (e.g. I recently figured out why I couldn't connect
> > to the Internet with the ISP-provided ‘4G minimodem’ -- DNS was b0rken). 
> > So explaining forward? to laypeople might take some care.
> > 
> > Writing a corresponding ‘system test’ in gnu/tests/networking.scm is
> > recommended.
> > 
> > Greetings,
> > Maxime.
> Thanks for the pointers Maxime.
> 
> I'm not an expert in networking but I can briefly tell about my use case here.
> basically my setup accomplishes two things: any machine connected to the 
> server running guix and wireguard should be able to browse the internet like a 
> normal vpn (using the server's ip address) and any client theoretically could 
> see each other. Right now I use this capability to play 0ad with friends, in 
> the future there will be apps running in different clients, accessible to 
> anyone inside vpn.
> 
> That said, I'm back here to ask one more thing. I cloned guix and followed the 
> manual to create an --pure environment and authenticated the commits. This 
> machine is a different one from my server, here I have guix running on top of 
> manjaro (an arch gnu/linux flavor).
> 
> I started changing code inside vpn.scm and my approach was to "make && make 
> check" after changes to see if it would still build. But this week, after a 
> git pull to update the repo and using make, I'm now greeted with
> 
> error: failed to load 'gnu/packages/perl.scm':
> ice-9/eval.scm:293:34: In procedure abi-check: #<record-type <package>>: 
> record ABI mismatch; recompilation needed
> 
> I will still spend some time with this error, but I found worth to ask: is 
> this approach of "make && make check" a reasonable one?

If you see ‘recompilation needed’, recompile with "make clean && make".

>  Is there a way to test 
> a guix system without installing it? Packages I know we can, but system 
> capabilities like vpn I'm not sure.

You could create a VM: "./pre-inst-env guix system vm the-configuration.scm --root=run-the-vm.sh
&& ./run-the-vm.sh".  Or possibly "./pre-inst-env guix system reconfigure the-config.scm",
if you only don't want to install guix, but reconfiguring the system is fine.

(You can do almost everything from ./pre-inst-env that can be done without.
The exception is if you modify the guix daemon (code under nix/), then you
may need to restart it from the local checkout.)

Greetings,
Maxime.

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