| 1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980 |
- Linux IEEE 802.15.4 implementation
- Introduction
- ============
- The Linux-ZigBee project goal is to provide complete implementation
- of IEEE 802.15.4 / ZigBee / 6LoWPAN protocols. IEEE 802.15.4 is a stack
- of protocols for organizing Low-Rate Wireless Personal Area Networks.
- Currently only IEEE 802.15.4 layer is implemented. We have choosen
- to use plain Berkeley socket API, the generic Linux networking stack
- to transfer IEEE 802.15.4 messages and a special protocol over genetlink
- for configuration/management
- Socket API
- ==========
- int sd = socket(PF_IEEE802154, SOCK_DGRAM, 0);
- .....
- The address family, socket addresses etc. are defined in the
- include/net/af_ieee802154.h header or in the special header
- in our userspace package (see either linux-zigbee sourceforge download page
- or git tree at git://linux-zigbee.git.sourceforge.net/gitroot/linux-zigbee).
- One can use SOCK_RAW for passing raw data towards device xmit function. YMMV.
- MLME - MAC Level Management
- ============================
- Most of IEEE 802.15.4 MLME interfaces are directly mapped on netlink commands.
- See the include/net/nl802154.h header. Our userspace tools package
- (see above) provides CLI configuration utility for radio interfaces and simple
- coordinator for IEEE 802.15.4 networks as an example users of MLME protocol.
- Kernel side
- =============
- Like with WiFi, there are several types of devices implementing IEEE 802.15.4.
- 1) 'HardMAC'. The MAC layer is implemented in the device itself, the device
- exports MLME and data API.
- 2) 'SoftMAC' or just radio. These types of devices are just radio transceivers
- possibly with some kinds of acceleration like automatic CRC computation and
- comparation, automagic ACK handling, address matching, etc.
- Those types of devices require different approach to be hooked into Linux kernel.
- HardMAC
- =======
- 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. 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
- required.
- We provide an example of simple HardMAC driver at drivers/ieee802154/fakehard.c
- SoftMAC
- =======
- We are going to provide intermediate layer implementing IEEE 802.15.4 MAC
- in software. This is currently WIP.
- See header include/net/mac802154.h and several drivers in drivers/ieee802154/.
|
