tools: cleanup host-side network setup

[miri64]

The Issue

With https://github.com/RIOT-OS/RIOT/pull/14454 now merged, we have a total of 3 start_network.sh scripts:

• The original one for ethos,
• A slightly improved, but SLIP-specific version (using getopt to parse the command-line parameters), and finally
• The new one for USB CDC-ECM.

For new communication protocols to allow for network communication between host and node such as PPP, the potential for further such scripts popping up, exists.

Moreover, for ethos there is also the setup_network.sh script used to setup testing environments only once which not only copies a lot from the ethos version of the start_network.sh script, but also has some overlap with tapsetup. tapsetup set's up TAP interfaces for native in a bridge and has the distinct advantage of supporting multiple platforms (Linux, Mac OSX, and FreeBSD) and being well tested on them.

Another issue is that both tapsetup and the start_network.sh/setup_network.sh scripts of ethos destroy each others environments if not used carefully, which can lead to a lot of frustration when running host-interaction based tests, like the scapy once on multiple boards including native.

Finally, it is quite annoying for testing, that the host-interaction between host and node can be quite different for native and ethos-based communication: tapsetup creates the TAP interfaces in a bridge, so multiple native instances can communicate among each other and with the host, ethos's script just create a bare TAP interface. For the native case the host needs to communicate over the bridge's interface, for ethos-based tests, over the TAP interface. The first is the case since interfaces in a bridge are only reachable from the bridge on the host machine, and not directly accessible for reception of packages.

Proposed solution

1. Unify start_network.sh to use setup_network.sh which in turn uses tapsetup to create TAP interfaces including a bridge (or for SLIP and USB CDC-ECM: add respective interface to bridge).
   • the uplink type could be provided as a parameter
2. Fold native as a new uplink type into that script.
3. Use start_network.sh as terminal program for all applications that require it.
4. (optional) Add state file (to /tmp) that keeps track of created interfaces and their associated bridges and make scripts idempotent.

Issues solved as a side-effect

• ethos-based applications may not work on Arch Linux when used with raw ethos as the interface needs to brought up manually before starting the application (see https://github.com/RIOT-OS/RIOT/pull/13802): The outright usage of start_network.sh sets the TAP interface to up.
• multiple ethos/SLIP/CDC-ECM could communicate with each other over the same host.
• There may be potential for making reset work better with native.

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. If you want me to ignore this issue, please mark it with the "State: don't stale" label. Thank you for your contributions.

[stale[bot]]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. If you want me to ignore this issue, please mark it with the "State: don't stale" label. Thank you for your contributions.

[maribu]

Ping?

[miri64]

Started working on that, got other responsibilities, project got staled, no idea which state it is now ^^" Still, would be nice to have!