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diff --git a/Documentation/networking/ieee802154.txt b/Documentation/networking/ieee802154.txt deleted file mode 100644 index e74d8e1da0e2..000000000000 --- a/Documentation/networking/ieee802154.txt +++ /dev/null @@ -1,177 +0,0 @@ - - Linux IEEE 802.15.4 implementation - - -Introduction -============ -The IEEE 802.15.4 working group focuses on standardization of the bottom -two layers: Medium Access Control (MAC) and Physical access (PHY). And there -are mainly two options available for upper layers: - - ZigBee - proprietary protocol from the ZigBee Alliance - - 6LoWPAN - IPv6 networking over low rate personal area networks - -The goal of the Linux-wpan is to provide a complete implementation -of the IEEE 802.15.4 and 6LoWPAN protocols. IEEE 802.15.4 is a stack -of protocols for organizing Low-Rate Wireless Personal Area Networks. - -The stack is composed of three main parts: - - IEEE 802.15.4 layer; We have chosen to use plain Berkeley socket API, - the generic Linux networking stack to transfer IEEE 802.15.4 data - messages and a special protocol over netlink for configuration/management - - MAC - provides access to shared channel and reliable data delivery - - PHY - represents device drivers - - -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 the userspace package (see either http://wpan.cakelab.org/ or the -git tree at https://github.com/linux-wpan/wpan-tools). - - -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 a management (e.g. 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 overridden 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. The fields -assoc_req, assoc_resp, disassoc_req, start_req, and scan_req are optional. -All other fields are required. - - -SoftMAC -======= - -The MAC is the middle layer in the IEEE 802.15.4 Linux stack. This moment it -provides interface for drivers registration and management of slave interfaces. - -NOTE: Currently the only monitor device type is supported - it's IEEE 802.15.4 -stack interface for network sniffers (e.g. WireShark). - -This layer is going to be extended soon. - -See header include/net/mac802154.h and several drivers in -drivers/net/ieee802154/. - - -Device drivers API -================== - -The include/net/mac802154.h defines following functions: - - struct ieee802154_hw * - ieee802154_alloc_hw(size_t priv_data_len, const struct ieee802154_ops *ops): - allocation of IEEE 802.15.4 compatible hardware device - - - void ieee802154_free_hw(struct ieee802154_hw *hw): - freeing allocated hardware device - - - int ieee802154_register_hw(struct ieee802154_hw *hw): - register PHY which is the allocated hardware device, in the system - - - void ieee802154_unregister_hw(struct ieee802154_hw *hw): - freeing registered PHY - - - void ieee802154_rx_irqsafe(struct ieee802154_hw *hw, struct sk_buff *skb, - u8 lqi): - telling 802.15.4 module there is a new received frame in the skb with - the RF Link Quality Indicator (LQI) from the hardware device - - - void ieee802154_xmit_complete(struct ieee802154_hw *hw, struct sk_buff *skb, - bool ifs_handling): - telling 802.15.4 module the frame in the skb is or going to be - transmitted through the hardware device - -The device driver must implement the following callbacks in the IEEE 802.15.4 -operations structure at least: -struct ieee802154_ops { - ... - int (*start)(struct ieee802154_hw *hw); - void (*stop)(struct ieee802154_hw *hw); - ... - int (*xmit_async)(struct ieee802154_hw *hw, struct sk_buff *skb); - int (*ed)(struct ieee802154_hw *hw, u8 *level); - int (*set_channel)(struct ieee802154_hw *hw, u8 page, u8 channel); - ... -}; - - - int start(struct ieee802154_hw *hw): - handler that 802.15.4 module calls for the hardware device initialization. - - - void stop(struct ieee802154_hw *hw): - handler that 802.15.4 module calls for the hardware device cleanup. - - - int xmit_async(struct ieee802154_hw *hw, struct sk_buff *skb): - handler that 802.15.4 module calls for each frame in the skb going to be - transmitted through the hardware device. - - - int ed(struct ieee802154_hw *hw, u8 *level): - handler that 802.15.4 module calls for Energy Detection from the hardware - device. - - - int set_channel(struct ieee802154_hw *hw, u8 page, u8 channel): - set radio for listening on specific channel of the hardware device. - -Moreover IEEE 802.15.4 device operations structure should be filled. - -Fake drivers -============ - -In addition there is a driver available which simulates a real device with -SoftMAC (fakelb - IEEE 802.15.4 loopback driver) interface. This option -provides a possibility to test and debug the stack without usage of real hardware. - -See sources in drivers/net/ieee802154 folder for more details. - - -6LoWPAN Linux implementation -============================ - -The IEEE 802.15.4 standard specifies an MTU of 127 bytes, yielding about 80 -octets of actual MAC payload once security is turned on, on a wireless link -with a link throughput of 250 kbps or less. The 6LoWPAN adaptation format -[RFC4944] was specified to carry IPv6 datagrams over such constrained links, -taking into account limited bandwidth, memory, or energy resources that are -expected in applications such as wireless Sensor Networks. [RFC4944] defines -a Mesh Addressing header to support sub-IP forwarding, a Fragmentation header -to support the IPv6 minimum MTU requirement [RFC2460], and stateless header -compression for IPv6 datagrams (LOWPAN_HC1 and LOWPAN_HC2) to reduce the -relatively large IPv6 and UDP headers down to (in the best case) several bytes. - -In September 2011 the standard update was published - [RFC6282]. -It deprecates HC1 and HC2 compression and defines IPHC encoding format which is -used in this Linux implementation. - -All the code related to 6lowpan you may find in files: net/6lowpan/* -and net/ieee802154/6lowpan/* - -To setup a 6LoWPAN interface you need: -1. Add IEEE802.15.4 interface and set channel and PAN ID; -2. Add 6lowpan interface by command like: - # ip link add link wpan0 name lowpan0 type lowpan -3. Bring up 'lowpan0' interface |