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authorLinus Torvalds <torvalds@linux-foundation.org>2019-03-05 08:26:13 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2019-03-05 08:26:13 -0800
commit6456300356433873309a1cae6aa05e77d6b59153 (patch)
tree3158f04f2ca63a48e4d3021aba31aee8f18221cf /Documentation/networking/ieee802154.rst
parentMerge tag 'leds-for-5.1-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/j.anaszewski/linux-leds (diff)
parentMerge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net (diff)
downloadlinux-dev-6456300356433873309a1cae6aa05e77d6b59153.tar.xz
linux-dev-6456300356433873309a1cae6aa05e77d6b59153.zip
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next
Pull networking updates from David Miller: "Here we go, another merge window full of networking and #ebpf changes: 1) Snoop DHCPACKS in batman-adv to learn MAC/IP pairs in the DHCP range without dealing with floods of ARP traffic, from Linus Lüssing. 2) Throttle buffered multicast packet transmission in mt76, from Felix Fietkau. 3) Support adaptive interrupt moderation in ice, from Brett Creeley. 4) A lot of struct_size conversions, from Gustavo A. R. Silva. 5) Add peek/push/pop commands to bpftool, as well as bash completion, from Stanislav Fomichev. 6) Optimize sk_msg_clone(), from Vakul Garg. 7) Add SO_BINDTOIFINDEX, from David Herrmann. 8) Be more conservative with local resends due to local congestion, from Yuchung Cheng. 9) Allow vetoing of unsupported VXLAN FDBs, from Petr Machata. 10) Add health buffer support to devlink, from Eran Ben Elisha. 11) Add TXQ scheduling API to mac80211, from Toke Høiland-Jørgensen. 12) Add statistics to basic packet scheduler filter, from Cong Wang. 13) Add GRE tunnel support for mlxsw Spectrum-2, from Nir Dotan. 14) Lots of new IP tunneling forwarding tests, also from Nir Dotan. 15) Add 3ad stats to bonding, from Nikolay Aleksandrov. 16) Lots of probing improvements for bpftool, from Quentin Monnet. 17) Various nfp drive #ebpf JIT improvements from Jakub Kicinski. 18) Allow #ebpf programs to access gso_segs from skb shared info, from Eric Dumazet. 19) Add sock_diag support for AF_XDP sockets, from Björn Töpel. 20) Support 22260 iwlwifi devices, from Luca Coelho. 21) Use rbtree for ipv6 defragmentation, from Peter Oskolkov. 22) Add JMP32 instruction class support to #ebpf, from Jiong Wang. 23) Add spinlock support to #ebpf, from Alexei Starovoitov. 24) Support 256-bit keys and TLS 1.3 in ktls, from Dave Watson. 25) Add device infomation API to devlink, from Jakub Kicinski. 26) Add new timestamping socket options which are y2038 safe, from Deepa Dinamani. 27) Add RX checksum offloading for various sh_eth chips, from Sergei Shtylyov. 28) Flow offload infrastructure, from Pablo Neira Ayuso. 29) Numerous cleanups, improvements, and bug fixes to the PHY layer and many drivers from Heiner Kallweit. 30) Lots of changes to try and make packet scheduler classifiers run lockless as much as possible, from Vlad Buslov. 31) Support BCM957504 chip in bnxt_en driver, from Erik Burrows. 32) Add concurrency tests to tc-tests infrastructure, from Vlad Buslov. 33) Add hwmon support to aquantia, from Heiner Kallweit. 34) Allow 64-bit values for SO_MAX_PACING_RATE, from Eric Dumazet. And I would be remiss if I didn't thank the various major networking subsystem maintainers for integrating much of this work before I even saw it. Alexei Starovoitov, Daniel Borkmann, Pablo Neira Ayuso, Johannes Berg, Kalle Valo, and many others. Thank you!" * git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (2207 commits) net/sched: avoid unused-label warning net: ignore sysctl_devconf_inherit_init_net without SYSCTL phy: mdio-mux: fix Kconfig dependencies net: phy: use phy_modify_mmd_changed in genphy_c45_an_config_aneg net: dsa: mv88e6xxx: add call to mv88e6xxx_ports_cmode_init to probe for new DSA framework selftest/net: Remove duplicate header sky2: Disable MSI on Dell Inspiron 1545 and Gateway P-79 net/mlx5e: Update tx reporter status in case channels were successfully opened devlink: Add support for direct reporter health state update devlink: Update reporter state to error even if recover aborted sctp: call iov_iter_revert() after sending ABORT team: Free BPF filter when unregistering netdev ip6mr: Do not call __IP6_INC_STATS() from preemptible context isdn: mISDN: Fix potential NULL pointer dereference of kzalloc net: dsa: mv88e6xxx: support in-band signalling on SGMII ports with external PHYs cxgb4/chtls: Prefix adapter flags with CXGB4 net-sysfs: Switch to bitmap_zalloc() mellanox: Switch to bitmap_zalloc() bpf: add test cases for non-pointer sanitiation logic mlxsw: i2c: Extend initialization by querying resources data ...
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+===============================
+IEEE 802.15.4 Developer's Guide
+===============================
+
+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
+==========
+
+.. c:function:: 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).
+
+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
+
+Drivers
+=======
+
+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/.
+
+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.
+
+Device drivers API
+==================
+
+The include/net/mac802154.h defines following functions:
+
+.. c:function:: struct ieee802154_dev *ieee802154_alloc_device (size_t priv_size, struct ieee802154_ops *ops)
+
+Allocation of IEEE 802.15.4 compatible device.
+
+.. c:function:: void ieee802154_free_device(struct ieee802154_dev *dev)
+
+Freeing allocated device.
+
+.. c:function:: int ieee802154_register_device(struct ieee802154_dev *dev)
+
+Register PHY in the system.
+
+.. c:function:: void ieee802154_unregister_device(struct ieee802154_dev *dev)
+
+Freeing registered PHY.
+
+.. c:function:: 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.
+
+.. c:function:: 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);
+ ...
+ };
+
+.. c:function:: int start(struct ieee802154_hw *hw):
+
+Handler that 802.15.4 module calls for the hardware device initialization.
+
+.. c:function:: void stop(struct ieee802154_hw *hw):
+
+Handler that 802.15.4 module calls for the hardware device cleanup.
+
+.. c:function:: 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.
+
+.. c:function:: int ed(struct ieee802154_hw *hw, u8 *level):
+
+Handler that 802.15.4 module calls for Energy Detection from the hardware
+device.
+
+.. c:function:: 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.