drivers: ethos needs OS X support

[kaspar030]

Now that #4438 is in, the host side needs OS X support.
I don't have an OS X machine, so doing this remotely would suck.

Could anyone look into this? wink @thomaseichinger?

[kYc0o]

I can test it in native MAC but I cannot succeed to flash a samr21... there is any special procedure? I have this tools installed and in my path:

193:gnrc_border_router facosta$ openocd --version
GNU ARM Eclipse 64-bits Open On-Chip Debugger 0.10.0-dev-00287-g85cec24 (2016-01-10-12:03)
Licensed under GNU GPL v2
For bug reports, read
    http://openocd.org/doc/doxygen/bugs.html
193:gnrc_border_router facosta$ arm-none-eabi-gcc --version
arm-none-eabi-gcc (GNU Tools for ARM Embedded Processors) 5.2.1 20151202 (release) [ARM/embedded-5-branch revision 231848]
Copyright (C) 2015 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

edit:
the error:

/Users/facosta/git/RIOT/dist/tools/openocd/openocd.sh flash
### Flashing Target ###
GNU ARM Eclipse 64-bits Open On-Chip Debugger 0.10.0-dev-00287-g85cec24 (2016-01-10-12:03)
Licensed under GNU GPL v2
For bug reports, read
    http://openocd.org/doc/doxygen/bugs.html
/Users/facosta/git/RIOT/boards/samr21-xpro/dist/openocd.cfg:1: Error: Can't find board/atmel_samr21_xplained_pro.cfg
in procedure 'script' 
at file "embedded:startup.tcl", line 60
at file "/Users/facosta/git/RIOT/boards/samr21-xpro/dist/openocd.cfg", line 1
Done flashing

[BytesGalore]

@kYc0o you need to use an OpenOCD version that has cmsis-dap and hidapi-libusb [1].
But you can easily build your own one just as we described for watr.li [2] (scroll down to Building OpenOCD part)

I hope this helps.

[1] https://github.com/RIOT-OS/RIOT/wiki/Board%3A-SAMR21-xpro#flashing-the-device
[2] http://watr.li/samr21-dev-setup-ubuntu.html

[kYc0o]

I succeeded with the setup but I fairly understand how ethos is actually using tun/tap interfaces. I found that this library [1] can be very useful, but my question is: does ethos need a tun and a tap interface? or only a tap interface should be enough?

[1] https://github.com/LaKabane/libtuntap

[kaspar030]

does ethos need a tun and a tap interface? or only a tap interface should be enough?

Yes, tap only is enough, and ethos only uses a tap interface. You're probably confused by the fact both tun and tap are initialized using "/dev/net/tun", but the actual ioctl selects tap mode (using "IFF_TAP" parameter), which in ethos is supplied in the flag argument to "tun_alloc()".

[kYc0o]

Ok great, yeah, I was talking with Oleg about that and I'll try with the tap interface. I'll try to create a PR with this functionality once #4725 is merged.

[kaspar030]

I'll try to create a PR with this functionality once #4725 is merged.

There might be a chicken and egg problem. Can't merge #4725 without ethos OS X support as it would break the border router example for OS X.
You could maybe create a PR on top of #4725, and we merge your's as soon as #4725 is in?

[kYc0o]

Ok so I will prepare the PR as soon as possible, but since the implementation is quite different so far, the script could not be used on OS X (ip command does not exist...) so my idea is to give the parameters to another program which will set up the tap interface and then use it on ethos.

[kaspar030]

the script could not be used on OS X

You could rename the script to "start_network_linux.sh" and create another osx variant, possibly sourcing shared functionality.

[kYc0o]

I think this cannot be done for this release, so I'll move it for the next one.