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().
  ...

1 files changed, 498 insertions, 0 deletions

diff --git a/Documentation/bpf/map_sockmap.rst b/Documentation/bpf/map_sockmap.rst
new file mode 100644
index 000000000..cc92047c6
--- /dev/null
+++ b/Documentation/bpf/map_sockmap.rst
@@ -0,0 +1,498 @@
+.. SPDX-License-Identifier: GPL-2.0-only
+.. Copyright Red Hat
+
+==============================================
+BPF_MAP_TYPE_SOCKMAP and BPF_MAP_TYPE_SOCKHASH
+==============================================
+
+.. note::
+   - ``BPF_MAP_TYPE_SOCKMAP`` was introduced in kernel version 4.14
+   - ``BPF_MAP_TYPE_SOCKHASH`` was introduced in kernel version 4.18
+
+``BPF_MAP_TYPE_SOCKMAP`` and ``BPF_MAP_TYPE_SOCKHASH`` maps can be used to
+redirect skbs between sockets or to apply policy at the socket level based on
+the result of a BPF (verdict) program with the help of the BPF helpers
+``bpf_sk_redirect_map()``, ``bpf_sk_redirect_hash()``,
+``bpf_msg_redirect_map()`` and ``bpf_msg_redirect_hash()``.
+
+``BPF_MAP_TYPE_SOCKMAP`` is backed by an array that uses an integer key as the
+index to look up a reference to a ``struct sock``. The map values are socket
+descriptors. Similarly, ``BPF_MAP_TYPE_SOCKHASH`` is a hash backed BPF map that
+holds references to sockets via their socket descriptors.
+
+.. note::
+    The value type is either __u32 or __u64; the latter (__u64) is to support
+    returning socket cookies to userspace. Returning the ``struct sock *`` that
+    the map holds to user-space is neither safe nor useful.
+
+These maps may have BPF programs attached to them, specifically a parser program
+and a verdict program. The parser program determines how much data has been
+parsed and therefore how much data needs to be queued to come to a verdict. The
+verdict program is essentially the redirect program and can return a verdict
+of ``__SK_DROP``, ``__SK_PASS``, or ``__SK_REDIRECT``.
+
+When a socket is inserted into one of these maps, its socket callbacks are
+replaced and a ``struct sk_psock`` is attached to it. Additionally, this
+``sk_psock`` inherits the programs that are attached to the map.
+
+A sock object may be in multiple maps, but can only inherit a single
+parse or verdict program. If adding a sock object to a map would result
+in having multiple parser programs the update will return an EBUSY error.
+
+The supported programs to attach to these maps are:
+
+.. code-block:: c
+
+	struct sk_psock_progs {
+		struct bpf_prog *msg_parser;
+		struct bpf_prog *stream_parser;
+		struct bpf_prog *stream_verdict;
+		struct bpf_prog	*skb_verdict;
+	};
+
+.. note::
+    Users are not allowed to attach ``stream_verdict`` and ``skb_verdict``
+    programs to the same map.
+
+The attach types for the map programs are:
+
+- ``msg_parser`` program - ``BPF_SK_MSG_VERDICT``.
+- ``stream_parser`` program - ``BPF_SK_SKB_STREAM_PARSER``.
+- ``stream_verdict`` program - ``BPF_SK_SKB_STREAM_VERDICT``.
+- ``skb_verdict`` program - ``BPF_SK_SKB_VERDICT``.
+
+There are additional helpers available to use with the parser and verdict
+programs: ``bpf_msg_apply_bytes()`` and ``bpf_msg_cork_bytes()``. With
+``bpf_msg_apply_bytes()`` BPF programs can tell the infrastructure how many
+bytes the given verdict should apply to. The helper ``bpf_msg_cork_bytes()``
+handles a different case where a BPF program cannot reach a verdict on a msg
+until it receives more bytes AND the program doesn't want to forward the packet
+until it is known to be good.
+
+Finally, the helpers ``bpf_msg_pull_data()`` and ``bpf_msg_push_data()`` are
+available to ``BPF_PROG_TYPE_SK_MSG`` BPF programs to pull in data and set the
+start and end pointers to given values or to add metadata to the ``struct
+sk_msg_buff *msg``.
+
+All these helpers will be described in more detail below.
+
+Usage
+=====
+Kernel BPF
+----------
+bpf_msg_redirect_map()
+^^^^^^^^^^^^^^^^^^^^^^
+.. code-block:: c
+
+	long bpf_msg_redirect_map(struct sk_msg_buff *msg, struct bpf_map *map, u32 key, u64 flags)
+
+This helper is used in programs implementing policies at the socket level. If
+the message ``msg`` is allowed to pass (i.e., if the verdict BPF program
+returns ``SK_PASS``), redirect it to the socket referenced by ``map`` (of type
+``BPF_MAP_TYPE_SOCKMAP``) at index ``key``. Both ingress and egress interfaces
+can be used for redirection. The ``BPF_F_INGRESS`` value in ``flags`` is used
+to select the ingress path otherwise the egress path is selected. This is the
+only flag supported for now.
+
+Returns ``SK_PASS`` on success, or ``SK_DROP`` on error.
+
+bpf_sk_redirect_map()
+^^^^^^^^^^^^^^^^^^^^^
+.. code-block:: c
+
+    long bpf_sk_redirect_map(struct sk_buff *skb, struct bpf_map *map, u32 key u64 flags)
+
+Redirect the packet to the socket referenced by ``map`` (of type
+``BPF_MAP_TYPE_SOCKMAP``) at index ``key``. Both ingress and egress interfaces
+can be used for redirection. The ``BPF_F_INGRESS`` value in ``flags`` is used
+to select the ingress path otherwise the egress path is selected. This is the
+only flag supported for now.
+
+Returns ``SK_PASS`` on success, or ``SK_DROP`` on error.
+
+bpf_map_lookup_elem()
+^^^^^^^^^^^^^^^^^^^^^
+.. code-block:: c
+
+    void *bpf_map_lookup_elem(struct bpf_map *map, const void *key)
+
+socket entries of type ``struct sock *`` can be retrieved using the
+``bpf_map_lookup_elem()`` helper.
+
+bpf_sock_map_update()
+^^^^^^^^^^^^^^^^^^^^^
+.. code-block:: c
+
+    long bpf_sock_map_update(struct bpf_sock_ops *skops, struct bpf_map *map, void *key, u64 flags)
+
+Add an entry to, or update a ``map`` referencing sockets. The ``skops`` is used
+as a new value for the entry associated to ``key``. 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.
+
+If the ``map`` has BPF programs (parser and verdict), those will be inherited
+by the socket being added. If the socket is already attached to BPF programs,
+this results in an error.
+
+Returns 0 on success, or a negative error in case of failure.
+
+bpf_sock_hash_update()
+^^^^^^^^^^^^^^^^^^^^^^
+.. code-block:: c
+
+    long bpf_sock_hash_update(struct bpf_sock_ops *skops, struct bpf_map *map, void *key, u64 flags)
+
+Add an entry to, or update a sockhash ``map`` referencing sockets. The ``skops``
+is used as a new value for the entry associated to ``key``.
+
+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.
+
+If the ``map`` has BPF programs (parser and verdict), those will be inherited
+by the socket being added. If the socket is already attached to BPF programs,
+this results in an error.
+
+Returns 0 on success, or a negative error in case of failure.
+
+bpf_msg_redirect_hash()
+^^^^^^^^^^^^^^^^^^^^^^^
+.. code-block:: c
+
+    long bpf_msg_redirect_hash(struct sk_msg_buff *msg, struct bpf_map *map, void *key, u64 flags)
+
+This helper is used in programs implementing policies at the socket level. If
+the message ``msg`` is allowed to pass (i.e., if the verdict BPF program returns
+``SK_PASS``), redirect it to the socket referenced by ``map`` (of type
+``BPF_MAP_TYPE_SOCKHASH``) using hash ``key``. Both ingress and egress
+interfaces can be used for redirection. The ``BPF_F_INGRESS`` value in
+``flags`` is used to select the ingress path otherwise the egress path is
+selected. This is the only flag supported for now.
+
+Returns ``SK_PASS`` on success, or ``SK_DROP`` on error.
+
+bpf_sk_redirect_hash()
+^^^^^^^^^^^^^^^^^^^^^^
+.. code-block:: c
+
+    long bpf_sk_redirect_hash(struct sk_buff *skb, struct bpf_map *map, void *key, u64 flags)
+
+This helper is used in programs implementing policies at the skb socket level.
+If the sk_buff ``skb`` is allowed to pass (i.e., if the verdict BPF program
+returns ``SK_PASS``), redirect it to the socket referenced by ``map`` (of type
+``BPF_MAP_TYPE_SOCKHASH``) using hash ``key``. Both ingress and egress
+interfaces can be used for redirection. The ``BPF_F_INGRESS`` value in
+``flags`` is used to select the ingress path otherwise the egress path is
+selected. This is the only flag supported for now.
+
+Returns ``SK_PASS`` on success, or ``SK_DROP`` on error.
+
+bpf_msg_apply_bytes()
+^^^^^^^^^^^^^^^^^^^^^^
+.. code-block:: c
+
+    long bpf_msg_apply_bytes(struct sk_msg_buff *msg, u32 bytes)
+
+For socket policies, apply the verdict of the BPF program to the next (number
+of ``bytes``) of message ``msg``. For example, this helper can be used in the
+following cases:
+
+- A single ``sendmsg()`` or ``sendfile()`` system call contains multiple
+  logical messages that the BPF program is supposed to read and for which it
+  should apply a verdict.
+- A BPF program only cares to read the first ``bytes`` of a ``msg``. If the
+  message has a large payload, then setting up and calling the BPF program
+  repeatedly for all bytes, even though the verdict is already known, would
+  create unnecessary overhead.
+
+Returns 0
+
+bpf_msg_cork_bytes()
+^^^^^^^^^^^^^^^^^^^^^^
+.. code-block:: c
+
+    long bpf_msg_cork_bytes(struct sk_msg_buff *msg, u32 bytes)
+
+For socket policies, prevent the execution of the verdict BPF program for
+message ``msg`` until the number of ``bytes`` have been accumulated.
+
+This can be used when one needs a specific number of bytes before a verdict can
+be assigned, even if the data spans multiple ``sendmsg()`` or ``sendfile()``
+calls.
+
+Returns 0
+
+bpf_msg_pull_data()
+^^^^^^^^^^^^^^^^^^^^^^
+.. code-block:: c
+
+    long bpf_msg_pull_data(struct sk_msg_buff *msg, u32 start, u32 end, u64 flags)
+
+For socket policies, pull in non-linear data from user space for ``msg`` and set
+pointers ``msg->data`` and ``msg->data_end`` to ``start`` and ``end`` bytes
+offsets into ``msg``, respectively.
+
+If a program of type ``BPF_PROG_TYPE_SK_MSG`` is run on a ``msg`` it can only
+parse data that the (``data``, ``data_end``) pointers have already consumed.
+For ``sendmsg()`` hooks this is likely the first scatterlist element. But for
+calls relying on the ``sendpage`` handler (e.g., ``sendfile()``) this will be
+the range (**0**, **0**) because the data is shared with user space and by
+default the objective is to avoid allowing user space to modify data while (or
+after) BPF verdict is being decided. This helper can be used to pull in data
+and to set the start and end pointers to given values. Data will be copied if
+necessary (i.e., if data was not linear and if start and end pointers do not
+point to the same chunk).
+
+A call to this helper is susceptible to change the underlying packet buffer.
+Therefore, at load time, all checks on pointers previously done by the verifier
+are invalidated and must be performed again, if the helper is used in
+combination with direct packet access.
+
+All values for ``flags`` are reserved for future usage, and must be left at
+zero.
+
+Returns 0 on success, or a negative error in case of failure.
+
+bpf_map_lookup_elem()
+^^^^^^^^^^^^^^^^^^^^^
+
+.. code-block:: c
+
+	void *bpf_map_lookup_elem(struct bpf_map *map, const void *key)
+
+Look up a socket entry in the sockmap or sockhash map.
+
+Returns the socket entry associated to ``key``, or NULL if no entry was found.
+
+bpf_map_update_elem()
+^^^^^^^^^^^^^^^^^^^^^
+.. code-block:: c
+
+	long bpf_map_update_elem(struct bpf_map *map, const void *key, const void *value, u64 flags)
+
+Add or update a socket entry in a sockmap or sockhash.
+
+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.
+
+Returns 0 on success, or a negative error in case of failure.
+
+bpf_map_delete_elem()
+^^^^^^^^^^^^^^^^^^^^^^
+.. code-block:: c
+
+    long bpf_map_delete_elem(struct bpf_map *map, const void *key)
+
+Delete a socket entry from a sockmap or a sockhash.
+
+Returns	0 on success, or a negative error in case of failure.
+
+User space
+----------
+bpf_map_update_elem()
+^^^^^^^^^^^^^^^^^^^^^
+.. code-block:: c
+
+	int bpf_map_update_elem(int fd, const void *key, const void *value, __u64 flags)
+
+Sockmap entries can be added or updated using the ``bpf_map_update_elem()``
+function. The ``key`` parameter is the index value of the sockmap array. And the
+``value`` parameter is the FD value of that socket.
+
+Under the hood, the sockmap update function uses the socket FD value to
+retrieve the associated socket and its attached psock.
+
+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)
+
+Sockmap entries can be retrieved using the ``bpf_map_lookup_elem()`` function.
+
+.. note::
+	The entry returned is a socket cookie rather than a socket itself.
+
+bpf_map_delete_elem()
+^^^^^^^^^^^^^^^^^^^^^
+.. code-block:: c
+
+    int bpf_map_delete_elem(int fd, const void *key)
+
+Sockmap entries can be deleted using the ``bpf_map_delete_elem()``
+function.
+
+Returns 0 on success, or negative error in case of failure.
+
+Examples
+========
+
+Kernel BPF
+----------
+Several examples of the use of sockmap APIs can be found in:
+
+- `tools/testing/selftests/bpf/progs/test_sockmap_kern.h`_
+- `tools/testing/selftests/bpf/progs/sockmap_parse_prog.c`_
+- `tools/testing/selftests/bpf/progs/sockmap_verdict_prog.c`_
+- `tools/testing/selftests/bpf/progs/test_sockmap_listen.c`_
+- `tools/testing/selftests/bpf/progs/test_sockmap_update.c`_
+
+The following code snippet shows how to declare a sockmap.
+
+.. code-block:: c
+
+	struct {
+		__uint(type, BPF_MAP_TYPE_SOCKMAP);
+		__uint(max_entries, 1);
+		__type(key, __u32);
+		__type(value, __u64);
+	} sock_map_rx SEC(".maps");
+
+The following code snippet shows a sample parser program.
+
+.. code-block:: c
+
+	SEC("sk_skb/stream_parser")
+	int bpf_prog_parser(struct __sk_buff *skb)
+	{
+		return skb->len;
+	}
+
+The following code snippet shows a simple verdict program that interacts with a
+sockmap to redirect traffic to another socket based on the local port.
+
+.. code-block:: c
+
+	SEC("sk_skb/stream_verdict")
+	int bpf_prog_verdict(struct __sk_buff *skb)
+	{
+		__u32 lport = skb->local_port;
+		__u32 idx = 0;
+
+		if (lport == 10000)
+			return bpf_sk_redirect_map(skb, &sock_map_rx, idx, 0);
+
+		return SK_PASS;
+	}
+
+The following code snippet shows how to declare a sockhash map.
+
+.. code-block:: c
+
+	struct socket_key {
+		__u32 src_ip;
+		__u32 dst_ip;
+		__u32 src_port;
+		__u32 dst_port;
+	};
+
+	struct {
+		__uint(type, BPF_MAP_TYPE_SOCKHASH);
+		__uint(max_entries, 1);
+		__type(key, struct socket_key);
+		__type(value, __u64);
+	} sock_hash_rx SEC(".maps");
+
+The following code snippet shows a simple verdict program that interacts with a
+sockhash to redirect traffic to another socket based on a hash of some of the
+skb parameters.
+
+.. code-block:: c
+
+	static inline
+	void extract_socket_key(struct __sk_buff *skb, struct socket_key *key)
+	{
+		key->src_ip = skb->remote_ip4;
+		key->dst_ip = skb->local_ip4;
+		key->src_port = skb->remote_port >> 16;
+		key->dst_port = (bpf_htonl(skb->local_port)) >> 16;
+	}
+
+	SEC("sk_skb/stream_verdict")
+	int bpf_prog_verdict(struct __sk_buff *skb)
+	{
+		struct socket_key key;
+
+		extract_socket_key(skb, &key);
+
+		return bpf_sk_redirect_hash(skb, &sock_hash_rx, &key, 0);
+	}
+
+User space
+----------
+Several examples of the use of sockmap APIs can be found in:
+
+- `tools/testing/selftests/bpf/prog_tests/sockmap_basic.c`_
+- `tools/testing/selftests/bpf/test_sockmap.c`_
+- `tools/testing/selftests/bpf/test_maps.c`_
+
+The following code sample shows how to create a sockmap, attach a parser and
+verdict program, as well as add a socket entry.
+
+.. code-block:: c
+
+	int create_sample_sockmap(int sock, int parse_prog_fd, int verdict_prog_fd)
+	{
+		int index = 0;
+		int map, err;
+
+		map = bpf_map_create(BPF_MAP_TYPE_SOCKMAP, NULL, sizeof(int), sizeof(int), 1, NULL);
+		if (map < 0) {
+			fprintf(stderr, "Failed to create sockmap: %s\n", strerror(errno));
+			return -1;
+		}
+
+		err = bpf_prog_attach(parse_prog_fd, map, BPF_SK_SKB_STREAM_PARSER, 0);
+		if (err){
+			fprintf(stderr, "Failed to attach_parser_prog_to_map: %s\n", strerror(errno));
+			goto out;
+		}
+
+		err = bpf_prog_attach(verdict_prog_fd, map, BPF_SK_SKB_STREAM_VERDICT, 0);
+		if (err){
+			fprintf(stderr, "Failed to attach_verdict_prog_to_map: %s\n", strerror(errno));
+			goto out;
+		}
+
+		err = bpf_map_update_elem(map, &index, &sock, BPF_NOEXIST);
+		if (err) {
+			fprintf(stderr, "Failed to update sockmap: %s\n", strerror(errno));
+			goto out;
+		}
+
+	out:
+		close(map);
+		return err;
+	}
+
+References
+===========
+
+- https://github.com/jrfastab/linux-kernel-xdp/commit/c89fd73cb9d2d7f3c716c3e00836f07b1aeb261f
+- https://lwn.net/Articles/731133/
+- http://vger.kernel.org/lpc_net2018_talks/ktls_bpf_paper.pdf
+- https://lwn.net/Articles/748628/
+- https://lore.kernel.org/bpf/20200218171023.844439-7-jakub@cloudflare.com/
+
+.. _`tools/testing/selftests/bpf/progs/test_sockmap_kern.h`: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/testing/selftests/bpf/progs/test_sockmap_kern.h
+.. _`tools/testing/selftests/bpf/progs/sockmap_parse_prog.c`: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/testing/selftests/bpf/progs/sockmap_parse_prog.c
+.. _`tools/testing/selftests/bpf/progs/sockmap_verdict_prog.c`: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/testing/selftests/bpf/progs/sockmap_verdict_prog.c
+.. _`tools/testing/selftests/bpf/prog_tests/sockmap_basic.c`: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/testing/selftests/bpf/prog_tests/sockmap_basic.c
+.. _`tools/testing/selftests/bpf/test_sockmap.c`: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/testing/selftests/bpf/test_sockmap.c
+.. _`tools/testing/selftests/bpf/test_maps.c`: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/testing/selftests/bpf/test_maps.c
+.. _`tools/testing/selftests/bpf/progs/test_sockmap_listen.c`: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/testing/selftests/bpf/progs/test_sockmap_listen.c
+.. _`tools/testing/selftests/bpf/progs/test_sockmap_update.c`: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/tools/testing/selftests/bpf/progs/test_sockmap_update.c