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author | 2023-02-21 18:24:12 -0800 | |
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committer | 2023-02-21 18:24:12 -0800 | |
commit | 5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 (patch) | |
tree | cc5c2d0a898769fd59549594fedb3ee6f84e59a0 /Documentation/bpf/libbpf/libbpf_naming_convention.rst | |
download | linux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.tar.gz linux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.zip |
Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted
Pull networking updates from Jakub Kicinski:
"Core:
- Add dedicated kmem_cache for typical/small skb->head, avoid having
to access struct page at kfree time, and improve memory use.
- Introduce sysctl to set default RPS configuration for new netdevs.
- Define Netlink protocol specification format which can be used to
describe messages used by each family and auto-generate parsers.
Add tools for generating kernel data structures and uAPI headers.
- Expose all net/core sysctls inside netns.
- Remove 4s sleep in netpoll if carrier is instantly detected on
boot.
- Add configurable limit of MDB entries per port, and port-vlan.
- Continue populating drop reasons throughout the stack.
- Retire a handful of legacy Qdiscs and classifiers.
Protocols:
- Support IPv4 big TCP (TSO frames larger than 64kB).
- Add IP_LOCAL_PORT_RANGE socket option, to control local port range
on socket by socket basis.
- Track and report in procfs number of MPTCP sockets used.
- Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path
manager.
- IPv6: don't check net.ipv6.route.max_size and rely on garbage
collection to free memory (similarly to IPv4).
- Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986).
- ICMP: add per-rate limit counters.
- Add support for user scanning requests in ieee802154.
- Remove static WEP support.
- Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate
reporting.
- WiFi 7 EHT channel puncturing support (client & AP).
BPF:
- Add a rbtree data structure following the "next-gen data structure"
precedent set by recently added linked list, that is, by using
kfunc + kptr instead of adding a new BPF map type.
- Expose XDP hints via kfuncs with initial support for RX hash and
timestamp metadata.
- Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to
better support decap on GRE tunnel devices not operating in collect
metadata.
- Improve x86 JIT's codegen for PROBE_MEM runtime error checks.
- Remove the need for trace_printk_lock for bpf_trace_printk and
bpf_trace_vprintk helpers.
- Extend libbpf's bpf_tracing.h support for tracing arguments of
kprobes/uprobes and syscall as a special case.
- Significantly reduce the search time for module symbols by
livepatch and BPF.
- Enable cpumasks to be used as kptrs, which is useful for tracing
programs tracking which tasks end up running on which CPUs in
different time intervals.
- Add support for BPF trampoline on s390x and riscv64.
- Add capability to export the XDP features supported by the NIC.
- Add __bpf_kfunc tag for marking kernel functions as kfuncs.
- Add cgroup.memory=nobpf kernel parameter option to disable BPF
memory accounting for container environments.
Netfilter:
- Remove the CLUSTERIP target. It has been marked as obsolete for
years, and we still have WARN splats wrt races of the out-of-band
/proc interface installed by this target.
- Add 'destroy' commands to nf_tables. They are identical to the
existing 'delete' commands, but do not return an error if the
referenced object (set, chain, rule...) did not exist.
Driver API:
- Improve cpumask_local_spread() locality to help NICs set the right
IRQ affinity on AMD platforms.
- Separate C22 and C45 MDIO bus transactions more clearly.
- Introduce new DCB table to control DSCP rewrite on egress.
- Support configuration of Physical Layer Collision Avoidance (PLCA)
Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of
shared medium Ethernet.
- Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing
preemption of low priority frames by high priority frames.
- Add support for controlling MACSec offload using netlink SET.
- Rework devlink instance refcounts to allow registration and
de-registration under the instance lock. Split the code into
multiple files, drop some of the unnecessarily granular locks and
factor out common parts of netlink operation handling.
- Add TX frame aggregation parameters (for USB drivers).
- Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning
messages with notifications for debug.
- Allow offloading of UDP NEW connections via act_ct.
- Add support for per action HW stats in TC.
- Support hardware miss to TC action (continue processing in SW from
a specific point in the action chain).
- Warn if old Wireless Extension user space interface is used with
modern cfg80211/mac80211 drivers. Do not support Wireless
Extensions for Wi-Fi 7 devices at all. Everyone should switch to
using nl80211 interface instead.
- Improve the CAN bit timing configuration. Use extack to return
error messages directly to user space, update the SJW handling,
including the definition of a new default value that will benefit
CAN-FD controllers, by increasing their oscillator tolerance.
New hardware / drivers:
- Ethernet:
- nVidia BlueField-3 support (control traffic driver)
- Ethernet support for imx93 SoCs
- Motorcomm yt8531 gigabit Ethernet PHY
- onsemi NCN26000 10BASE-T1S PHY (with support for PLCA)
- Microchip LAN8841 PHY (incl. cable diagnostics and PTP)
- Amlogic gxl MDIO mux
- WiFi:
- RealTek RTL8188EU (rtl8xxxu)
- Qualcomm Wi-Fi 7 devices (ath12k)
- CAN:
- Renesas R-Car V4H
Drivers:
- Bluetooth:
- Set Per Platform Antenna Gain (PPAG) for Intel controllers.
- Ethernet NICs:
- Intel (1G, igc):
- support TSN / Qbv / packet scheduling features of i226 model
- Intel (100G, ice):
- use GNSS subsystem instead of TTY
- multi-buffer XDP support
- extend support for GPIO pins to E823 devices
- nVidia/Mellanox:
- update the shared buffer configuration on PFC commands
- implement PTP adjphase function for HW offset control
- TC support for Geneve and GRE with VF tunnel offload
- more efficient crypto key management method
- multi-port eswitch support
- Netronome/Corigine:
- add DCB IEEE support
- support IPsec offloading for NFP3800
- Freescale/NXP (enetc):
- support XDP_REDIRECT for XDP non-linear buffers
- improve reconfig, avoid link flap and waiting for idle
- support MAC Merge layer
- Other NICs:
- sfc/ef100: add basic devlink support for ef100
- ionic: rx_push mode operation (writing descriptors via MMIO)
- bnxt: use the auxiliary bus abstraction for RDMA
- r8169: disable ASPM and reset bus in case of tx timeout
- cpsw: support QSGMII mode for J721e CPSW9G
- cpts: support pulse-per-second output
- ngbe: add an mdio bus driver
- usbnet: optimize usbnet_bh() by avoiding unnecessary queuing
- r8152: handle devices with FW with NCM support
- amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation
- virtio-net: support multi buffer XDP
- virtio/vsock: replace virtio_vsock_pkt with sk_buff
- tsnep: XDP support
- Ethernet high-speed switches:
- nVidia/Mellanox (mlxsw):
- add support for latency TLV (in FW control messages)
- Microchip (sparx5):
- separate explicit and implicit traffic forwarding rules, make
the implicit rules always active
- add support for egress DSCP rewrite
- IS0 VCAP support (Ingress Classification)
- IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS
etc.)
- ES2 VCAP support (Egress Access Control)
- support for Per-Stream Filtering and Policing (802.1Q,
8.6.5.1)
- Ethernet embedded switches:
- Marvell (mv88e6xxx):
- add MAB (port auth) offload support
- enable PTP receive for mv88e6390
- NXP (ocelot):
- support MAC Merge layer
- support for the the vsc7512 internal copper phys
- Microchip:
- lan9303: convert to PHYLINK
- lan966x: support TC flower filter statistics
- lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x
- lan937x: support Credit Based Shaper configuration
- ksz9477: support Energy Efficient Ethernet
- other:
- qca8k: convert to regmap read/write API, use bulk operations
- rswitch: Improve TX timestamp accuracy
- Intel WiFi (iwlwifi):
- EHT (Wi-Fi 7) rate reporting
- STEP equalizer support: transfer some STEP (connection to radio
on platforms with integrated wifi) related parameters from the
BIOS to the firmware.
- Qualcomm 802.11ax WiFi (ath11k):
- IPQ5018 support
- Fine Timing Measurement (FTM) responder role support
- channel 177 support
- MediaTek WiFi (mt76):
- per-PHY LED support
- mt7996: EHT (Wi-Fi 7) support
- Wireless Ethernet Dispatch (WED) reset support
- switch to using page pool allocator
- RealTek WiFi (rtw89):
- support new version of Bluetooth co-existance
- Mobile:
- rmnet: support TX aggregation"
* tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits)
page_pool: add a comment explaining the fragment counter usage
net: ethtool: fix __ethtool_dev_mm_supported() implementation
ethtool: pse-pd: Fix double word in comments
xsk: add linux/vmalloc.h to xsk.c
sefltests: netdevsim: wait for devlink instance after netns removal
selftest: fib_tests: Always cleanup before exit
net/mlx5e: Align IPsec ASO result memory to be as required by hardware
net/mlx5e: TC, Set CT miss to the specific ct action instance
net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG
net/mlx5: Refactor tc miss handling to a single function
net/mlx5: Kconfig: Make tc offload depend on tc skb extension
net/sched: flower: Support hardware miss to tc action
net/sched: flower: Move filter handle initialization earlier
net/sched: cls_api: Support hardware miss to tc action
net/sched: Rename user cookie and act cookie
sfc: fix builds without CONFIG_RTC_LIB
sfc: clean up some inconsistent indentings
net/mlx4_en: Introduce flexible array to silence overflow warning
net: lan966x: Fix possible deadlock inside PTP
net/ulp: Remove redundant ->clone() test in inet_clone_ulp().
...
Diffstat (limited to 'Documentation/bpf/libbpf/libbpf_naming_convention.rst')
-rw-r--r-- | Documentation/bpf/libbpf/libbpf_naming_convention.rst | 193 |
1 files changed, 193 insertions, 0 deletions
diff --git a/Documentation/bpf/libbpf/libbpf_naming_convention.rst b/Documentation/bpf/libbpf/libbpf_naming_convention.rst new file mode 100644 index 000000000..b5b41b61b --- /dev/null +++ b/Documentation/bpf/libbpf/libbpf_naming_convention.rst @@ -0,0 +1,193 @@ +.. SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) + +API naming convention +===================== + +libbpf API provides access to a few logically separated groups of +functions and types. Every group has its own naming convention +described here. It's recommended to follow these conventions whenever a +new function or type is added to keep libbpf API clean and consistent. + +All types and functions provided by libbpf API should have one of the +following prefixes: ``bpf_``, ``btf_``, ``libbpf_``, ``btf_dump_``, +``ring_buffer_``, ``perf_buffer_``. + +System call wrappers +-------------------- + +System call wrappers are simple wrappers for commands supported by +sys_bpf system call. These wrappers should go to ``bpf.h`` header file +and map one to one to corresponding commands. + +For example ``bpf_map_lookup_elem`` wraps ``BPF_MAP_LOOKUP_ELEM`` +command of sys_bpf, ``bpf_prog_attach`` wraps ``BPF_PROG_ATTACH``, etc. + +Objects +------- + +Another class of types and functions provided by libbpf API is "objects" +and functions to work with them. Objects are high-level abstractions +such as BPF program or BPF map. They're represented by corresponding +structures such as ``struct bpf_object``, ``struct bpf_program``, +``struct bpf_map``, etc. + +Structures are forward declared and access to their fields should be +provided via corresponding getters and setters rather than directly. + +These objects are associated with corresponding parts of ELF object that +contains compiled BPF programs. + +For example ``struct bpf_object`` represents ELF object itself created +from an ELF file or from a buffer, ``struct bpf_program`` represents a +program in ELF object and ``struct bpf_map`` is a map. + +Functions that work with an object have names built from object name, +double underscore and part that describes function purpose. + +For example ``bpf_object__open`` consists of the name of corresponding +object, ``bpf_object``, double underscore and ``open`` that defines the +purpose of the function to open ELF file and create ``bpf_object`` from +it. + +All objects and corresponding functions other than BTF related should go +to ``libbpf.h``. BTF types and functions should go to ``btf.h``. + +Auxiliary functions +------------------- + +Auxiliary functions and types that don't fit well in any of categories +described above should have ``libbpf_`` prefix, e.g. +``libbpf_get_error`` or ``libbpf_prog_type_by_name``. + +ABI +--- + +libbpf can be both linked statically or used as DSO. To avoid possible +conflicts with other libraries an application is linked with, all +non-static libbpf symbols should have one of the prefixes mentioned in +API documentation above. See API naming convention to choose the right +name for a new symbol. + +Symbol visibility +----------------- + +libbpf follow the model when all global symbols have visibility "hidden" +by default and to make a symbol visible it has to be explicitly +attributed with ``LIBBPF_API`` macro. For example: + +.. code-block:: c + + LIBBPF_API int bpf_prog_get_fd_by_id(__u32 id); + +This prevents from accidentally exporting a symbol, that is not supposed +to be a part of ABI what, in turn, improves both libbpf developer- and +user-experiences. + +ABI versioning +-------------- + +To make future ABI extensions possible libbpf ABI is versioned. +Versioning is implemented by ``libbpf.map`` version script that is +passed to linker. + +Version name is ``LIBBPF_`` prefix + three-component numeric version, +starting from ``0.0.1``. + +Every time ABI is being changed, e.g. because a new symbol is added or +semantic of existing symbol is changed, ABI version should be bumped. +This bump in ABI version is at most once per kernel development cycle. + +For example, if current state of ``libbpf.map`` is: + +.. code-block:: none + + LIBBPF_0.0.1 { + global: + bpf_func_a; + bpf_func_b; + local: + \*; + }; + +, and a new symbol ``bpf_func_c`` is being introduced, then +``libbpf.map`` should be changed like this: + +.. code-block:: none + + LIBBPF_0.0.1 { + global: + bpf_func_a; + bpf_func_b; + local: + \*; + }; + LIBBPF_0.0.2 { + global: + bpf_func_c; + } LIBBPF_0.0.1; + +, where new version ``LIBBPF_0.0.2`` depends on the previous +``LIBBPF_0.0.1``. + +Format of version script and ways to handle ABI changes, including +incompatible ones, described in details in [1]. + +Stand-alone build +------------------- + +Under https://github.com/libbpf/libbpf there is a (semi-)automated +mirror of the mainline's version of libbpf for a stand-alone build. + +However, all changes to libbpf's code base must be upstreamed through +the mainline kernel tree. + + +API documentation convention +============================ + +The libbpf API is documented via comments above definitions in +header files. These comments can be rendered by doxygen and sphinx +for well organized html output. This section describes the +convention in which these comments should be formatted. + +Here is an example from btf.h: + +.. code-block:: c + + /** + * @brief **btf__new()** creates a new instance of a BTF object from the raw + * bytes of an ELF's BTF section + * @param data raw bytes + * @param size number of bytes passed in `data` + * @return new BTF object instance which has to be eventually freed with + * **btf__free()** + * + * On error, error-code-encoded-as-pointer is returned, not a NULL. To extract + * error code from such a pointer `libbpf_get_error()` should be used. If + * `libbpf_set_strict_mode(LIBBPF_STRICT_CLEAN_PTRS)` is enabled, NULL is + * returned on error instead. In both cases thread-local `errno` variable is + * always set to error code as well. + */ + +The comment must start with a block comment of the form '/\*\*'. + +The documentation always starts with a @brief directive. This line is a short +description about this API. It starts with the name of the API, denoted in bold +like so: **api_name**. Please include an open and close parenthesis if this is a +function. Follow with the short description of the API. A longer form description +can be added below the last directive, at the bottom of the comment. + +Parameters are denoted with the @param directive, there should be one for each +parameter. If this is a function with a non-void return, use the @return directive +to document it. + +License +------------------- + +libbpf is dual-licensed under LGPL 2.1 and BSD 2-Clause. + +Links +------------------- + +[1] https://www.akkadia.org/drepper/dsohowto.pdf + (Chapter 3. Maintaining APIs and ABIs). |