mac802154: fixed potential skb leak with mac802154_parse_frame_start

This patch fix a memory leak if received frame was not able to parse.

Signed-off-by: Martin Townsend <martin.townsend@xsilon.com>
Signed-off-by: Alexander Aring <alex.aring@gmail.com>
ieee802154: 6lowpan_rtnl: fix correct errno value

This patch correct the return value of lowpan_alloc_frag if an error
occur. Errno numbers should always be negative.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
ieee802154: mac802154: handle the reserved dest mode by dropping the packet

If received frame contains the reserved destination address mode. The
frame should be dropped and free the skb.

Signed-off-by: Martin Townsend <martin.townsend@xsilon.com>
Signed-off-by: Alexander Aring <alex.aring@gmail.com>
ieee802154: 6lowpan: ensure of sending 1280 packets

This patch changes the 1281 MTU to 1280. Others stack have only a 1280
byte array for uncompressed 6LoWPAN packets, this avoid that these
stacks have an overflow. Sending 1281 uncompressed 6LoWPAN packets isn't
also rfc complaint.

Signed-off-by: Alexander Aring <alex.aring@gmail.com>
ieee802154: 6lowpan: ensure MTU of 1280 for 6lowpan

This patch drops the userspace accessable sysfs entry for the maximum
datagram size of a 6LoWPAN fragment packet.

A fragment should not have a datagram size value greater than 1280 byte.
Instead of make this value configurable, we accept 1280 datagram size
fragment packets only.

Signed-off-by: Martin Townsend <martin.townsend@xsilon.com>
Signed-off-by: Alexander Aring <alex.aring@gmail.com>