Hi, Thanks for the feedback...
On Mon, 18 Apr 2022, at 14:51, Aleksander Morgado wrote: > Hey, > >> >> After having set up modemmanager properly, I still need to run `mmcli >> simple-connect...` each time I plug in the modem. Plus, the ID sometimes >> changes when re-plugging it, so I have to query the ID (sometimes the modem >> takes a while to show up too), and THEN manually connect it. >> >> Not a huge deal TBH, but still low-key annoying; it gets repetitive rather >> quickly. >> > > Yes, that is all expected. If you want an "automated" connection > management, you need something on top of MM to do it. MM just provides > APIs to control the modem, it doesn't do any logic by itself. No one > is expected to run --simple-connect every time to connect a modem, > there should be some other process in charge of doing that for you. > That makes sense: do one thing and to it well :) >> So I wrote a very little helper that listens on the D-Bus interface for new >> modems, and automatically connects them to the network (sim-pin and >> profile-id are read from a config file). Maybe this can be of use to others?: >> >> https://git.sr.ht/~whynothugo/mmctl >> >> Configuration of the network itself (e.g.: DHCP) is handled by the network >> manager service (systemd-networkd in my case) once wlan0 is up. >> > > Thanks for sharing! I'm sure this could be helpful to others. > > One thing I quickly spotted is that you're assuming DHCP can be run in > the modem, and this is not always the case. Instead, you should look > at the generated connected bearer object and see what are the > Ip4Config and Ip6Config property values. The bearer may report > "static" if the user should configure the IP settings provided by the > modem in the bearer object, or "dhcp" if the user should run DHCP (or > SLAAC for IPv6), or "ppp" if the user should run pppd over a specific > TTY port. > I don't exactly assume DHCP; the helper limits itself to connecting the modem to the cellular network and doesn't handle the IP layer at all. Establishing the upper-layer network connection is not handled deliberately, since that's handled by the network management service itself (systemd-networkd in my case). Presently, I _do_ have wwan0 configured to use DHCP (since my ISP uses this). However, systemd-networkd is adding native support for grabbing the details from ModemManager[1], so I'll just rely on that in future. [1]: https://github.com/systemd/systemd/pull/22315 >> Aside from sharing this very tiny tool, I wanted to also kind of suggest >> incorporating this functionality into modem-manager itself; adding support >> for configuration files where one can define sim-pin, profile-id, etc, and >> have modem-manager automatically connect when it's detected. >> > > This is not a task of ModemManager really. MM just provides a mean to > configure the modem, it is not in charge of the actual logic to > perform the connection, or what to do with the connection. Upper > layers like NetworkManager (in most distros), netifd (in openwrt) or > Shill (in ChromeOS) are the ones in charge of triggering the > connection setup and then configuring the net interface as requested. > All those upper layers already have ways to store connection settings > like APN, PIN, user/pass... Adding the complexity of managing all that > by MM automatically is not something I'd personally like to do. > Setting up a connection, along with default routes and every other > detail should be done by the network management logic in the system, > be it a ethernet, a wireless or a modem device. > Right! I currently use `iwd` to tell the wifi adapter "please connect to this AP". systemd-networkd then handles the IP configuration. My goal with mmctl is to have an analogous for modems; something that ONLY connects the modems, but leaves the IP configuration to the network management service. > That said, we could have a simple program like yours as an example in > the ModemManager sources, or even something that could be used in > setups where no other upper layer is available (e.g. assuming there > will be one single default route via the modem and such). I have > several examples like those that I could adapt, and ideally they would > be using libmm-glib (e.g. in python via GObject Introspection). I have > absolutely no idea if you can have automatic bindings like the ones we > have in python or javascript via GIR when using rust, is that a thing? > I'm currently using the D-Bus API directly (using zbus, a Rust library for connecting to D-Bus). Is is possible to generate bindings via GIR, but I'm not sure if there's any benefit so as to justify the added complexity. Maybe just adding a link to it in examples is enough. It might be enough for someone, or at least a sufficient reference. > Cheers! > > -- > Aleksander > https://aleksander.es -- Hugo Osvaldo Barrera
