ieee802154: document the skb->cb usage clearly.

See the header include/net/ieee802154_netdev.h. You have to implement Linux

net_device, with .type = ARPHRD_IEEE802154. Data is exchanged with socket family

code via plain sk_buffs. The control block of sk_buffs will contain additional

info as described in the struct ieee802154_mac_cb.

code via plain sk_buffs. On skb reception skb->cb must contain additional

info as described in the struct ieee802154_mac_cb. During packet transmission

the skb->cb is used to provide additional data to device's header_ops->create

function. Be aware, that this data can be overriden later (when socket code

submits skb to qdisc), so if you need something from that cb later, you should

store info in the skb->data on your own.

To hook the MLME interface you have to populate the ml_priv field of your

net_device with a pointer to struct ieee802154_mlme_ops instance. All fields are

in software. This is currently WIP.

See header include/net/mac802154.h and several drivers in drivers/ieee802154/.