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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/prog_cgroup_sysctl.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/prog_cgroup_sysctl.rst')
-rw-r--r-- | Documentation/bpf/prog_cgroup_sysctl.rst | 125 |
1 files changed, 125 insertions, 0 deletions
diff --git a/Documentation/bpf/prog_cgroup_sysctl.rst b/Documentation/bpf/prog_cgroup_sysctl.rst new file mode 100644 index 000000000..677d6c637 --- /dev/null +++ b/Documentation/bpf/prog_cgroup_sysctl.rst @@ -0,0 +1,125 @@ +.. SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) + +=========================== +BPF_PROG_TYPE_CGROUP_SYSCTL +=========================== + +This document describes ``BPF_PROG_TYPE_CGROUP_SYSCTL`` program type that +provides cgroup-bpf hook for sysctl. + +The hook has to be attached to a cgroup and will be called every time a +process inside that cgroup tries to read from or write to sysctl knob in proc. + +1. Attach type +************** + +``BPF_CGROUP_SYSCTL`` attach type has to be used to attach +``BPF_PROG_TYPE_CGROUP_SYSCTL`` program to a cgroup. + +2. Context +********** + +``BPF_PROG_TYPE_CGROUP_SYSCTL`` provides access to the following context from +BPF program:: + + struct bpf_sysctl { + __u32 write; + __u32 file_pos; + }; + +* ``write`` indicates whether sysctl value is being read (``0``) or written + (``1``). This field is read-only. + +* ``file_pos`` indicates file position sysctl is being accessed at, read + or written. This field is read-write. Writing to the field sets the starting + position in sysctl proc file ``read(2)`` will be reading from or ``write(2)`` + will be writing to. Writing zero to the field can be used e.g. to override + whole sysctl value by ``bpf_sysctl_set_new_value()`` on ``write(2)`` even + when it's called by user space on ``file_pos > 0``. Writing non-zero + value to the field can be used to access part of sysctl value starting from + specified ``file_pos``. Not all sysctl support access with ``file_pos != + 0``, e.g. writes to numeric sysctl entries must always be at file position + ``0``. See also ``kernel.sysctl_writes_strict`` sysctl. + +See `linux/bpf.h`_ for more details on how context field can be accessed. + +3. Return code +************** + +``BPF_PROG_TYPE_CGROUP_SYSCTL`` program must return one of the following +return codes: + +* ``0`` means "reject access to sysctl"; +* ``1`` means "proceed with access". + +If program returns ``0`` user space will get ``-1`` from ``read(2)`` or +``write(2)`` and ``errno`` will be set to ``EPERM``. + +4. Helpers +********** + +Since sysctl knob is represented by a name and a value, sysctl specific BPF +helpers focus on providing access to these properties: + +* ``bpf_sysctl_get_name()`` to get sysctl name as it is visible in + ``/proc/sys`` into provided by BPF program buffer; + +* ``bpf_sysctl_get_current_value()`` to get string value currently held by + sysctl into provided by BPF program buffer. This helper is available on both + ``read(2)`` from and ``write(2)`` to sysctl; + +* ``bpf_sysctl_get_new_value()`` to get new string value currently being + written to sysctl before actual write happens. This helper can be used only + on ``ctx->write == 1``; + +* ``bpf_sysctl_set_new_value()`` to override new string value currently being + written to sysctl before actual write happens. Sysctl value will be + overridden starting from the current ``ctx->file_pos``. If the whole value + has to be overridden BPF program can set ``file_pos`` to zero before calling + to the helper. This helper can be used only on ``ctx->write == 1``. New + string value set by the helper is treated and verified by kernel same way as + an equivalent string passed by user space. + +BPF program sees sysctl value same way as user space does in proc filesystem, +i.e. as a string. Since many sysctl values represent an integer or a vector +of integers, the following helpers can be used to get numeric value from the +string: + +* ``bpf_strtol()`` to convert initial part of the string to long integer + similar to user space `strtol(3)`_; +* ``bpf_strtoul()`` to convert initial part of the string to unsigned long + integer similar to user space `strtoul(3)`_; + +See `linux/bpf.h`_ for more details on helpers described here. + +5. Examples +*********** + +See `test_sysctl_prog.c`_ for an example of BPF program in C that access +sysctl name and value, parses string value to get vector of integers and uses +the result to make decision whether to allow or deny access to sysctl. + +6. Notes +******** + +``BPF_PROG_TYPE_CGROUP_SYSCTL`` is intended to be used in **trusted** root +environment, for example to monitor sysctl usage or catch unreasonable values +an application, running as root in a separate cgroup, is trying to set. + +Since `task_dfl_cgroup(current)` is called at `sys_read` / `sys_write` time it +may return results different from that at `sys_open` time, i.e. process that +opened sysctl file in proc filesystem may differ from process that is trying +to read from / write to it and two such processes may run in different +cgroups, what means ``BPF_PROG_TYPE_CGROUP_SYSCTL`` should not be used as a +security mechanism to limit sysctl usage. + +As with any cgroup-bpf program additional care should be taken if an +application running as root in a cgroup should not be allowed to +detach/replace BPF program attached by administrator. + +.. Links +.. _linux/bpf.h: ../../include/uapi/linux/bpf.h +.. _strtol(3): http://man7.org/linux/man-pages/man3/strtol.3p.html +.. _strtoul(3): http://man7.org/linux/man-pages/man3/strtoul.3p.html +.. _test_sysctl_prog.c: + ../../tools/testing/selftests/bpf/progs/test_sysctl_prog.c |