802.15.4 6LoWPAN ARPHRD changed

Hi,

the 6LoWPAN ARPHRD interface type is changed and will be at linux kernel version 4.1 or later to: ARPHRD_6LOWPAN, before it was ARPHRD_IEEE802154.

The reason was that a 802.15.4 and 6LoWPAN interface used the same ARPHRD_IEEE802154 type, that occurs several issues on other applications which can't decide if it's a 802154 or 6LoWPAN (IPv6) interface.

Since bluetooth 6LoWPAN introduced the ARPHRD_6LOWPAN we also decide that we using ARPHRD_6LOWPAN now.

The most applications getting the EUI64 address from the interface by evaluating the ARPHRD_IEEE802154. This should be the same for BT 6LoWPAN and 802.15.4 6LoWPAN, because both uses has an EUI64 address. Also the applications use-case for BT 6LoWPAN and 802.15.4 6LoWPAN should be the same. We can also introduce some other mechanism to detect the L2 interface type of an ARPHRD_6LOWPAN, if this is necessary.

For backwards compability it should be safe to add a:

case ARPHRD_6LOWPAN before or after ARPHRD_IEEE802154.

Example radvd in function update_device_info [0]:

switch (ifr.ifr_hwaddr.sa_family) {
...
case ARPHRD_IEEE802154:
case ARPHRD_6LOWPAN:

	...
	break;

...
}

But this handling is still a little bit wrong because ARPHRD_IEEE802154 are 802.15.4 interfaces which don't have IPv6 functionality.

Nevertheless I just want to leave a note to current common userspace applications which evaluating this UAPI value. That's why I cc'ed radvd and unstrung here.

- Alex

[0] https://github.com/reubenhwk/radvd/blob/master/device-linux.c#L82