1 2 Linux IEEE 802.15.4 implementation 3 4 5Introduction 6============ 7 8The Linux-ZigBee project goal is to provide complete implementation 9of IEEE 802.15.4 / ZigBee / 6LoWPAN protocols. IEEE 802.15.4 is a stack 10of protocols for organizing Low-Rate Wireless Personal Area Networks. 11 12Currently only IEEE 802.15.4 layer is implemented. We have chosen 13to use plain Berkeley socket API, the generic Linux networking stack 14to transfer IEEE 802.15.4 messages and a special protocol over genetlink 15for configuration/management 16 17 18Socket API 19========== 20 21int sd = socket(PF_IEEE802154, SOCK_DGRAM, 0); 22..... 23 24The address family, socket addresses etc. are defined in the 25include/net/af_ieee802154.h header or in the special header 26in our userspace package (see either linux-zigbee sourceforge download page 27or git tree at git://linux-zigbee.git.sourceforge.net/gitroot/linux-zigbee). 28 29One can use SOCK_RAW for passing raw data towards device xmit function. YMMV. 30 31 32MLME - MAC Level Management 33============================ 34 35Most of IEEE 802.15.4 MLME interfaces are directly mapped on netlink commands. 36See the include/net/nl802154.h header. Our userspace tools package 37(see above) provides CLI configuration utility for radio interfaces and simple 38coordinator for IEEE 802.15.4 networks as an example users of MLME protocol. 39 40 41Kernel side 42============= 43 44Like with WiFi, there are several types of devices implementing IEEE 802.15.4. 451) 'HardMAC'. The MAC layer is implemented in the device itself, the device 46 exports MLME and data API. 472) 'SoftMAC' or just radio. These types of devices are just radio transceivers 48 possibly with some kinds of acceleration like automatic CRC computation and 49 comparation, automagic ACK handling, address matching, etc. 50 51Those types of devices require different approach to be hooked into Linux kernel. 52 53 54HardMAC 55======= 56 57See the header include/net/ieee802154_netdev.h. You have to implement Linux 58net_device, with .type = ARPHRD_IEEE802154. Data is exchanged with socket family 59code via plain sk_buffs. On skb reception skb->cb must contain additional 60info as described in the struct ieee802154_mac_cb. During packet transmission 61the skb->cb is used to provide additional data to device's header_ops->create 62function. Be aware, that this data can be overriden later (when socket code 63submits skb to qdisc), so if you need something from that cb later, you should 64store info in the skb->data on your own. 65 66To hook the MLME interface you have to populate the ml_priv field of your 67net_device with a pointer to struct ieee802154_mlme_ops instance. All fields are 68required. 69 70We provide an example of simple HardMAC driver at drivers/ieee802154/fakehard.c 71 72 73SoftMAC 74======= 75 76We are going to provide intermediate layer implementing IEEE 802.15.4 MAC 77in software. This is currently WIP. 78 79See header include/net/mac802154.h and several drivers in drivers/ieee802154/. 80 81