Spike: sshnpd on Yocto

[cpswan]

Is your feature request related to a problem? Please describe.

We're coming across prospects who use The Yocto Project as the basis for their embedded systems (typically in devices built around Raspberry Pi Compute Module [CM]).

Describe the solution you'd like

Validate the mechanism by which the sshnpd binary can be placed into a build along with daemon config and keys.

Describe alternatives you've considered

We've already progressed work on OpenWRT, which is open used for similar purposes.

Additional context

We've already had sshnpd running on the earlier Yocto versions of Chirpstack, which now uses OpenWRT.

[cpswan]

I've got 'Poky' building and rebuilding. Next step is to create a custom app layer based on Cmake. Once that's done I should be able to slide in C sshnpd once it's ready. It might also be possible to use existing Dart based binaries.

Moving to PR82 and reducing SP.

[cpswan]

Custom CMake based layer running on Pi3.

I could continue with Dart version of sshnpd, but likely better to wait for C version.

[cpswan]

Code at https://github.com/atsign-foundation/meta-hellocmake

[cpswan]

I'll reuse what we do for OpenWRT with atsign-foundation/Atsign_OpenWRT_packages#9

[cpswan]

Superseded by #1568