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author | Linus Torvalds <torvalds@linux-foundation.org> | 2022-12-14 02:47:48 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-12-14 02:47:48 +0300 |
commit | 7e68dd7d07a28faa2e6574dd6b9dbd90cdeaae91 (patch) | |
tree | ae0427c5a3b905f24b3a44b510a9bcf35d9b67a3 /Documentation/bpf/map_queue_stack.rst | |
parent | 1ca06f1c1acecbe02124f14a37cce347b8c1a90c (diff) | |
parent | 7c4a6309e27f411743817fe74a832ec2d2798a4b (diff) | |
download | linux-7e68dd7d07a28faa2e6574dd6b9dbd90cdeaae91.tar.xz |
Merge tag 'net-next-6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next
Pull networking updates from Paolo Abeni:
"Core:
- Allow live renaming when an interface is up
- Add retpoline wrappers for tc, improving considerably the
performances of complex queue discipline configurations
- Add inet drop monitor support
- A few GRO performance improvements
- Add infrastructure for atomic dev stats, addressing long standing
data races
- De-duplicate common code between OVS and conntrack offloading
infrastructure
- A bunch of UBSAN_BOUNDS/FORTIFY_SOURCE improvements
- Netfilter: introduce packet parser for tunneled packets
- Replace IPVS timer-based estimators with kthreads to scale up the
workload with the number of available CPUs
- Add the helper support for connection-tracking OVS offload
BPF:
- Support for user defined BPF objects: the use case is to allocate
own objects, build own object hierarchies and use the building
blocks to build own data structures flexibly, for example, linked
lists in BPF
- Make cgroup local storage available to non-cgroup attached BPF
programs
- Avoid unnecessary deadlock detection and failures wrt BPF task
storage helpers
- A relevant bunch of BPF verifier fixes and improvements
- Veristat tool improvements to support custom filtering, sorting,
and replay of results
- Add LLVM disassembler as default library for dumping JITed code
- Lots of new BPF documentation for various BPF maps
- Add bpf_rcu_read_{,un}lock() support for sleepable programs
- Add RCU grace period chaining to BPF to wait for the completion of
access from both sleepable and non-sleepable BPF programs
- Add support storing struct task_struct objects as kptrs in maps
- Improve helper UAPI by explicitly defining BPF_FUNC_xxx integer
values
- Add libbpf *_opts API-variants for bpf_*_get_fd_by_id() functions
Protocols:
- TCP: implement Protective Load Balancing across switch links
- TCP: allow dynamically disabling TCP-MD5 static key, reverting back
to fast[er]-path
- UDP: Introduce optional per-netns hash lookup table
- IPv6: simplify and cleanup sockets disposal
- Netlink: support different type policies for each generic netlink
operation
- MPTCP: add MSG_FASTOPEN and FastOpen listener side support
- MPTCP: add netlink notification support for listener sockets events
- SCTP: add VRF support, allowing sctp sockets binding to VRF devices
- Add bridging MAC Authentication Bypass (MAB) support
- Extensions for Ethernet VPN bridging implementation to better
support multicast scenarios
- More work for Wi-Fi 7 support, comprising conversion of all the
existing drivers to internal TX queue usage
- IPSec: introduce a new offload type (packet offload) allowing
complete header processing and crypto offloading
- IPSec: extended ack support for more descriptive XFRM error
reporting
- RXRPC: increase SACK table size and move processing into a
per-local endpoint kernel thread, reducing considerably the
required locking
- IEEE 802154: synchronous send frame and extended filtering support,
initial support for scanning available 15.4 networks
- Tun: bump the link speed from 10Mbps to 10Gbps
- Tun/VirtioNet: implement UDP segmentation offload support
Driver API:
- PHY/SFP: improve power level switching between standard level 1 and
the higher power levels
- New API for netdev <-> devlink_port linkage
- PTP: convert existing drivers to new frequency adjustment
implementation
- DSA: add support for rx offloading
- Autoload DSA tagging driver when dynamically changing protocol
- Add new PCP and APPTRUST attributes to Data Center Bridging
- Add configuration support for 800Gbps link speed
- Add devlink port function attribute to enable/disable RoCE and
migratable
- Extend devlink-rate to support strict prioriry and weighted fair
queuing
- Add devlink support to directly reading from region memory
- New device tree helper to fetch MAC address from nvmem
- New big TCP helper to simplify temporary header stripping
New hardware / drivers:
- Ethernet:
- Marvel Octeon CNF95N and CN10KB Ethernet Switches
- Marvel Prestera AC5X Ethernet Switch
- WangXun 10 Gigabit NIC
- Motorcomm yt8521 Gigabit Ethernet
- Microchip ksz9563 Gigabit Ethernet Switch
- Microsoft Azure Network Adapter
- Linux Automation 10Base-T1L adapter
- PHY:
- Aquantia AQR112 and AQR412
- Motorcomm YT8531S
- PTP:
- Orolia ART-CARD
- WiFi:
- MediaTek Wi-Fi 7 (802.11be) devices
- RealTek rtw8821cu, rtw8822bu, rtw8822cu and rtw8723du USB
devices
- Bluetooth:
- Broadcom BCM4377/4378/4387 Bluetooth chipsets
- Realtek RTL8852BE and RTL8723DS
- Cypress.CYW4373A0 WiFi + Bluetooth combo device
Drivers:
- CAN:
- gs_usb: bus error reporting support
- kvaser_usb: listen only and bus error reporting support
- Ethernet NICs:
- Intel (100G):
- extend action skbedit to RX queue mapping
- implement devlink-rate support
- support direct read from memory
- nVidia/Mellanox (mlx5):
- SW steering improvements, increasing rules update rate
- Support for enhanced events compression
- extend H/W offload packet manipulation capabilities
- implement IPSec packet offload mode
- nVidia/Mellanox (mlx4):
- better big TCP support
- Netronome Ethernet NICs (nfp):
- IPsec offload support
- add support for multicast filter
- Broadcom:
- RSS and PTP support improvements
- AMD/SolarFlare:
- netlink extened ack improvements
- add basic flower matches to offload, and related stats
- Virtual NICs:
- ibmvnic: introduce affinity hint support
- small / embedded:
- FreeScale fec: add initial XDP support
- Marvel mv643xx_eth: support MII/GMII/RGMII modes for Kirkwood
- TI am65-cpsw: add suspend/resume support
- Mediatek MT7986: add RX wireless wthernet dispatch support
- Realtek 8169: enable GRO software interrupt coalescing per
default
- Ethernet high-speed switches:
- Microchip (sparx5):
- add support for Sparx5 TC/flower H/W offload via VCAP
- Mellanox mlxsw:
- add 802.1X and MAC Authentication Bypass offload support
- add ip6gre support
- Embedded Ethernet switches:
- Mediatek (mtk_eth_soc):
- improve PCS implementation, add DSA untag support
- enable flow offload support
- Renesas:
- add rswitch R-Car Gen4 gPTP support
- Microchip (lan966x):
- add full XDP support
- add TC H/W offload via VCAP
- enable PTP on bridge interfaces
- Microchip (ksz8):
- add MTU support for KSZ8 series
- Qualcomm 802.11ax WiFi (ath11k):
- support configuring channel dwell time during scan
- MediaTek WiFi (mt76):
- enable Wireless Ethernet Dispatch (WED) offload support
- add ack signal support
- enable coredump support
- remain_on_channel support
- Intel WiFi (iwlwifi):
- enable Wi-Fi 7 Extremely High Throughput (EHT) PHY capabilities
- 320 MHz channels support
- RealTek WiFi (rtw89):
- new dynamic header firmware format support
- wake-over-WLAN support"
* tag 'net-next-6.2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (2002 commits)
ipvs: fix type warning in do_div() on 32 bit
net: lan966x: Remove a useless test in lan966x_ptp_add_trap()
net: ipa: add IPA v4.7 support
dt-bindings: net: qcom,ipa: Add SM6350 compatible
bnxt: Use generic HBH removal helper in tx path
IPv6/GRO: generic helper to remove temporary HBH/jumbo header in driver
selftests: forwarding: Add bridge MDB test
selftests: forwarding: Rename bridge_mdb test
bridge: mcast: Support replacement of MDB port group entries
bridge: mcast: Allow user space to specify MDB entry routing protocol
bridge: mcast: Allow user space to add (*, G) with a source list and filter mode
bridge: mcast: Add support for (*, G) with a source list and filter mode
bridge: mcast: Avoid arming group timer when (S, G) corresponds to a source
bridge: mcast: Add a flag for user installed source entries
bridge: mcast: Expose __br_multicast_del_group_src()
bridge: mcast: Expose br_multicast_new_group_src()
bridge: mcast: Add a centralized error path
bridge: mcast: Place netlink policy before validation functions
bridge: mcast: Split (*, G) and (S, G) addition into different functions
bridge: mcast: Do not derive entry type from its filter mode
...
Diffstat (limited to 'Documentation/bpf/map_queue_stack.rst')
-rw-r--r-- | Documentation/bpf/map_queue_stack.rst | 146 |
1 files changed, 146 insertions, 0 deletions
diff --git a/Documentation/bpf/map_queue_stack.rst b/Documentation/bpf/map_queue_stack.rst new file mode 100644 index 000000000000..8d14ed49d6e1 --- /dev/null +++ b/Documentation/bpf/map_queue_stack.rst @@ -0,0 +1,146 @@ +.. SPDX-License-Identifier: GPL-2.0-only +.. Copyright (C) 2022 Red Hat, Inc. + +========================================= +BPF_MAP_TYPE_QUEUE and BPF_MAP_TYPE_STACK +========================================= + +.. note:: + - ``BPF_MAP_TYPE_QUEUE`` and ``BPF_MAP_TYPE_STACK`` were introduced + in kernel version 4.20 + +``BPF_MAP_TYPE_QUEUE`` provides FIFO storage and ``BPF_MAP_TYPE_STACK`` +provides LIFO storage for BPF programs. These maps support peek, pop and +push operations that are exposed to BPF programs through the respective +helpers. These operations are exposed to userspace applications using +the existing ``bpf`` syscall in the following way: + +- ``BPF_MAP_LOOKUP_ELEM`` -> peek +- ``BPF_MAP_LOOKUP_AND_DELETE_ELEM`` -> pop +- ``BPF_MAP_UPDATE_ELEM`` -> push + +``BPF_MAP_TYPE_QUEUE`` and ``BPF_MAP_TYPE_STACK`` do not support +``BPF_F_NO_PREALLOC``. + +Usage +===== + +Kernel BPF +---------- + +bpf_map_push_elem() +~~~~~~~~~~~~~~~~~~~ + +.. code-block:: c + + long bpf_map_push_elem(struct bpf_map *map, const void *value, u64 flags) + +An element ``value`` can be added to a queue or stack using the +``bpf_map_push_elem`` helper. The ``flags`` parameter must be set to +``BPF_ANY`` or ``BPF_EXIST``. If ``flags`` is set to ``BPF_EXIST`` then, +when the queue or stack is full, the oldest element will be removed to +make room for ``value`` to be added. Returns ``0`` on success, or +negative error in case of failure. + +bpf_map_peek_elem() +~~~~~~~~~~~~~~~~~~~ + +.. code-block:: c + + long bpf_map_peek_elem(struct bpf_map *map, void *value) + +This helper fetches an element ``value`` from a queue or stack without +removing it. Returns ``0`` on success, or negative error in case of +failure. + +bpf_map_pop_elem() +~~~~~~~~~~~~~~~~~~ + +.. code-block:: c + + long bpf_map_pop_elem(struct bpf_map *map, void *value) + +This helper removes an element into ``value`` from a queue or +stack. Returns ``0`` on success, or negative error in case of failure. + + +Userspace +--------- + +bpf_map_update_elem() +~~~~~~~~~~~~~~~~~~~~~ + +.. code-block:: c + + int bpf_map_update_elem (int fd, const void *key, const void *value, __u64 flags) + +A userspace program can push ``value`` onto a queue or stack using libbpf's +``bpf_map_update_elem`` function. The ``key`` parameter must be set to +``NULL`` and ``flags`` must be set to ``BPF_ANY`` or ``BPF_EXIST``, with the +same semantics as the ``bpf_map_push_elem`` kernel helper. Returns ``0`` on +success, or negative error in case of failure. + +bpf_map_lookup_elem() +~~~~~~~~~~~~~~~~~~~~~ + +.. code-block:: c + + int bpf_map_lookup_elem (int fd, const void *key, void *value) + +A userspace program can peek at the ``value`` at the head of a queue or stack +using the libbpf ``bpf_map_lookup_elem`` function. The ``key`` parameter must be +set to ``NULL``. Returns ``0`` on success, or negative error in case of +failure. + +bpf_map_lookup_and_delete_elem() +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +.. code-block:: c + + int bpf_map_lookup_and_delete_elem (int fd, const void *key, void *value) + +A userspace program can pop a ``value`` from the head of a queue or stack using +the libbpf ``bpf_map_lookup_and_delete_elem`` function. The ``key`` parameter +must be set to ``NULL``. Returns ``0`` on success, or negative error in case of +failure. + +Examples +======== + +Kernel BPF +---------- + +This snippet shows how to declare a queue in a BPF program: + +.. code-block:: c + + struct { + __uint(type, BPF_MAP_TYPE_QUEUE); + __type(value, __u32); + __uint(max_entries, 10); + } queue SEC(".maps"); + + +Userspace +--------- + +This snippet shows how to use libbpf's low-level API to create a queue from +userspace: + +.. code-block:: c + + int create_queue() + { + return bpf_map_create(BPF_MAP_TYPE_QUEUE, + "sample_queue", /* name */ + 0, /* key size, must be zero */ + sizeof(__u32), /* value size */ + 10, /* max entries */ + NULL); /* create options */ + } + + +References +========== + +https://lwn.net/ml/netdev/153986858555.9127.14517764371945179514.stgit@kernel/ |