From 5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Tue, 21 Feb 2023 18:24:12 -0800 Subject: Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 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(). ... --- Documentation/bpf/map_xskmap.rst | 192 +++++++++++++++++++++++++++++++++++++++ 1 file changed, 192 insertions(+) create mode 100644 Documentation/bpf/map_xskmap.rst (limited to 'Documentation/bpf/map_xskmap.rst') diff --git a/Documentation/bpf/map_xskmap.rst b/Documentation/bpf/map_xskmap.rst new file mode 100644 index 000000000..dc143edd9 --- /dev/null +++ b/Documentation/bpf/map_xskmap.rst @@ -0,0 +1,192 @@ +.. SPDX-License-Identifier: GPL-2.0-only +.. Copyright (C) 2022 Red Hat, Inc. + +=================== +BPF_MAP_TYPE_XSKMAP +=================== + +.. note:: + - ``BPF_MAP_TYPE_XSKMAP`` was introduced in kernel version 4.18 + +The ``BPF_MAP_TYPE_XSKMAP`` is used as a backend map for XDP BPF helper +call ``bpf_redirect_map()`` and ``XDP_REDIRECT`` action, like 'devmap' and 'cpumap'. +This map type redirects raw XDP frames to `AF_XDP`_ sockets (XSKs), a new type of +address family in the kernel that allows redirection of frames from a driver to +user space without having to traverse the full network stack. An AF_XDP socket +binds to a single netdev queue. A mapping of XSKs to queues is shown below: + +.. code-block:: none + + +---------------------------------------------------+ + | xsk A | xsk B | xsk C |<---+ User space + =========================================================|========== + | Queue 0 | Queue 1 | Queue 2 | | Kernel + +---------------------------------------------------+ | + | Netdev eth0 | | + +---------------------------------------------------+ | + | +=============+ | | + | | key | xsk | | | + | +---------+ +=============+ | | + | | | | 0 | xsk A | | | + | | | +-------------+ | | + | | | | 1 | xsk B | | | + | | BPF |-- redirect -->+-------------+-------------+ + | | prog | | 2 | xsk C | | + | | | +-------------+ | + | | | | + | | | | + | +---------+ | + | | + +---------------------------------------------------+ + +.. note:: + An AF_XDP socket that is bound to a certain will *only* + accept XDP frames from that . If an XDP program tries to redirect + from a other than what the socket is bound to, the frame will + not be received on the socket. + +Typically an XSKMAP is created per netdev. This map contains an array of XSK File +Descriptors (FDs). The number of array elements is typically set or adjusted using +the ``max_entries`` map parameter. For AF_XDP ``max_entries`` is equal to the number +of queues supported by the netdev. + +.. note:: + Both the map key and map value size must be 4 bytes. + +Usage +===== + +Kernel BPF +---------- +bpf_redirect_map() +^^^^^^^^^^^^^^^^^^ +.. code-block:: c + + long bpf_redirect_map(struct bpf_map *map, u32 key, u64 flags) + +Redirect the packet to the endpoint referenced by ``map`` at index ``key``. +For ``BPF_MAP_TYPE_XSKMAP`` this map contains references to XSK FDs +for sockets attached to a netdev's queues. + +.. note:: + If the map is empty at an index, the packet is dropped. This means that it is + necessary to have an XDP program loaded with at least one XSK in the + XSKMAP to be able to get any traffic to user space through the socket. + +bpf_map_lookup_elem() +^^^^^^^^^^^^^^^^^^^^^ +.. code-block:: c + + void *bpf_map_lookup_elem(struct bpf_map *map, const void *key) + +XSK entry references of type ``struct xdp_sock *`` can be retrieved using the +``bpf_map_lookup_elem()`` helper. + +User space +---------- +.. note:: + XSK entries can only be updated/deleted from user space and not from + a BPF program. Trying to call these functions from a kernel BPF program will + result in the program failing to load and a verifier warning. + +bpf_map_update_elem() +^^^^^^^^^^^^^^^^^^^^^ +.. code-block:: c + + int bpf_map_update_elem(int fd, const void *key, const void *value, __u64 flags) + +XSK entries can be added or updated using the ``bpf_map_update_elem()`` +helper. The ``key`` parameter is equal to the queue_id of the queue the XSK +is attaching to. And the ``value`` parameter is the FD value of that socket. + +Under the hood, the XSKMAP update function uses the XSK FD value to retrieve the +associated ``struct xdp_sock`` instance. + +The flags argument can be one of the following: + +- BPF_ANY: Create a new element or update an existing element. +- BPF_NOEXIST: Create a new element only if it did not exist. +- BPF_EXIST: Update an existing element. + +bpf_map_lookup_elem() +^^^^^^^^^^^^^^^^^^^^^ +.. code-block:: c + + int bpf_map_lookup_elem(int fd, const void *key, void *value) + +Returns ``struct xdp_sock *`` or negative error in case of failure. + +bpf_map_delete_elem() +^^^^^^^^^^^^^^^^^^^^^ +.. code-block:: c + + int bpf_map_delete_elem(int fd, const void *key) + +XSK entries can be deleted using the ``bpf_map_delete_elem()`` +helper. This helper will return 0 on success, or negative error in case of +failure. + +.. note:: + When `libxdp`_ deletes an XSK it also removes the associated socket + entry from the XSKMAP. + +Examples +======== +Kernel +------ + +The following code snippet shows how to declare a ``BPF_MAP_TYPE_XSKMAP`` called +``xsks_map`` and how to redirect packets to an XSK. + +.. code-block:: c + + struct { + __uint(type, BPF_MAP_TYPE_XSKMAP); + __type(key, __u32); + __type(value, __u32); + __uint(max_entries, 64); + } xsks_map SEC(".maps"); + + + SEC("xdp") + int xsk_redir_prog(struct xdp_md *ctx) + { + __u32 index = ctx->rx_queue_index; + + if (bpf_map_lookup_elem(&xsks_map, &index)) + return bpf_redirect_map(&xsks_map, index, 0); + return XDP_PASS; + } + +User space +---------- + +The following code snippet shows how to update an XSKMAP with an XSK entry. + +.. code-block:: c + + int update_xsks_map(struct bpf_map *xsks_map, int queue_id, int xsk_fd) + { + int ret; + + ret = bpf_map_update_elem(bpf_map__fd(xsks_map), &queue_id, &xsk_fd, 0); + if (ret < 0) + fprintf(stderr, "Failed to update xsks_map: %s\n", strerror(errno)); + + return ret; + } + +For an example on how create AF_XDP sockets, please see the AF_XDP-example and +AF_XDP-forwarding programs in the `bpf-examples`_ directory in the `libxdp`_ repository. +For a detailed explanation of the AF_XDP interface please see: + +- `libxdp-readme`_. +- `AF_XDP`_ kernel documentation. + +.. note:: + The most comprehensive resource for using XSKMAPs and AF_XDP is `libxdp`_. + +.. _libxdp: https://github.com/xdp-project/xdp-tools/tree/master/lib/libxdp +.. _AF_XDP: https://www.kernel.org/doc/html/latest/networking/af_xdp.html +.. _bpf-examples: https://github.com/xdp-project/bpf-examples +.. _libxdp-readme: https://github.com/xdp-project/xdp-tools/tree/master/lib/libxdp#using-af_xdp-sockets -- cgit v1.2.3