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Documentation/networking/ieee802154: update MAC chapter
Update the documentation according to latest changes.
Signed-off-by: Alexander Smirnov <alex.bluesman.smirnov@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
authored by
alex.bluesman.smirnov@gmail.com
and committed by
David S. Miller
dd456d45
e1e49b64
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Documentation/networking/ieee802154.txt
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Documentation/networking/ieee802154.txt
···
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Introduction
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============
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The IEEE 802.15.4 working group focuses on standartization of bottom
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two layers: Medium Accsess Control (MAC) and Physical (PHY). And there
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are mainly two options available for upper layers:
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- ZigBee - proprietary protocol from ZigBee Alliance
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- 6LowPAN - IPv6 networking over low rate personal area networks
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The Linux-ZigBee project goal is to provide complete implementation
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of IEEE 802.15.4 / ZigBee / 6LoWPAN protocols. IEEE 802.15.4 is a stack
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of IEEE 802.15.4 and 6LoWPAN protocols. IEEE 802.15.4 is a stack
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of protocols for organizing Low-Rate Wireless Personal Area Networks.
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Currently only IEEE 802.15.4 layer is implemented. We have chosen
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to use plain Berkeley socket API, the generic Linux networking stack
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to transfer IEEE 802.15.4 messages and a special protocol over genetlink
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for configuration/management
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The stack is composed of three main parts:
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- IEEE 802.15.4 layer; We have chosen to use plain Berkeley socket API,
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the generic Linux networking stack to transfer IEEE 802.15.4 messages
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and a special protocol over genetlink for configuration/management
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- MAC - provides access to shared channel and reliable data delivery
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- PHY - represents device drivers
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Socket API
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One can use SOCK_RAW for passing raw data towards device xmit function. YMMV.
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MLME - MAC Level Management
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============================
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Most of IEEE 802.15.4 MLME interfaces are directly mapped on netlink commands.
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See the include/net/nl802154.h header. Our userspace tools package
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(see above) provides CLI configuration utility for radio interfaces and simple
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coordinator for IEEE 802.15.4 networks as an example users of MLME protocol.
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Kernel side
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=============
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···
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comparation, automagic ACK handling, address matching, etc.
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Those types of devices require different approach to be hooked into Linux kernel.
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MLME - MAC Level Management
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============================
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Most of IEEE 802.15.4 MLME interfaces are directly mapped on netlink commands.
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See the include/net/nl802154.h header. Our userspace tools package
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(see above) provides CLI configuration utility for radio interfaces and simple
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coordinator for IEEE 802.15.4 networks as an example users of MLME protocol.
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HardMAC
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SoftMAC
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=======
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We are going to provide intermediate layer implementing IEEE 802.15.4 MAC
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in software. This is currently WIP.
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The MAC is the middle layer in the IEEE 802.15.4 Linux stack. This moment it
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provides interface for drivers registration and management of slave interfaces.
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NOTE: Currently the only monitor device type is supported - it's IEEE 802.15.4
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stack interface for network sniffers (e.g. WireShark).
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This layer is going to be extended soon.
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See header include/net/mac802154.h and several drivers in drivers/ieee802154/.
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Device drivers API
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==================
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The include/net/mac802154.h defines following functions:
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- struct ieee802154_dev *ieee802154_alloc_device
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(size_t priv_size, struct ieee802154_ops *ops):
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allocation of IEEE 802.15.4 compatible device
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- void ieee802154_free_device(struct ieee802154_dev *dev):
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freeing allocated device
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- int ieee802154_register_device(struct ieee802154_dev *dev):
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register PHY in the system
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- void ieee802154_unregister_device(struct ieee802154_dev *dev):
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freeing registered PHY
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Moreover IEEE 802.15.4 device operations structure should be filled.
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Fake drivers
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============
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In addition there are two drivers available which simulate real devices with
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HardMAC (fakehard) and SoftMAC (fakelb - IEEE 802.15.4 loopback driver)
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interfaces. This option provides possibility to test and debug stack without
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usage of real hardware.
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See sources in drivers/ieee802154 folder for more details.
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6LoWPAN Linux implementation
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============================