dist/tools/{ethos,zep_dispatch,dose,sliptty,usb-cdc-ecm}: allow setting host ip

[mguetschow]

Contribution description

This adds an optional cmd option to start_network.sh for both ethos and zep_dispatch which allows to set the IP address automatically added on the host device (usually the development PC) when creating the tap interface. Additionally, the host address set now defaults to the same fd00:dead:beef::1.

examples/gnrc_border_router is adapted to showcase the usage.

Testing procedure

1. make -C examples/gnrc_border_router all term and ip a l tap0 in a separate shell to see the (new) default host address fd00:dead:beef::1.
2. same commands with IPV6_HOST_ADDR=2001:db8:1::1 to see the given host ip address is used. ping 2001:db8:1::1 in the RIOT shell to see it is reachable.
3. same commands with an actual board (tested with BOARD=nrf52840dk) to test ethos.

Issues/PRs references

This has been discussed with @miri64 previously.

[mguetschow]

Revisiting the README of the gnrc_border_router example, it turns out a ULA address is already automatically added by the respective scripts, although not the same one. I will have a look again and probably change the PR to make those addresses consistent per default and configurable.

[mguetschow]

I've changed the PR to allow setting the host IP address consistently for ethos and zep_dispatch. Now ready for review.

[miri64]

LGTM. But maybe the other integrations could benefit from this treatment as well:

• dist/tools/dose/start_network.sh
• dist/tools/sliptty/start_network.sh
• dist/tools/usb-cdc-ecm/start_network.sh

[mguetschow]

But maybe the other integrations could benefit from this treatment as well:

Added similar changes to the other integrations now. Successfully tested sliptty with examples/gnrc_border_router, but couldn't find information on how to test the others. Maybe someone could give me a hint?

[mguetschow]

Now this has been updated to support all five integrations, and I've successfully tested ethos, zep_dispatch, sliptty and usb-cdc-ecm with the gnrc_border_router example.