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, 290 insertions, 0 deletions

diff --git a/Documentation/networking/kcm.rst b/Documentation/networking/kcm.rst
new file mode 100644
index 000000000..db0f5560a
--- /dev/null
+++ b/Documentation/networking/kcm.rst
@@ -0,0 +1,290 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=============================
+Kernel Connection Multiplexor
+=============================
+
+Kernel Connection Multiplexor (KCM) is a mechanism that provides a message based
+interface over TCP for generic application protocols. With KCM an application
+can efficiently send and receive application protocol messages over TCP using
+datagram sockets.
+
+KCM implements an NxM multiplexor in the kernel as diagrammed below::
+
+    +------------+   +------------+   +------------+   +------------+
+    | KCM socket |   | KCM socket |   | KCM socket |   | KCM socket |
+    +------------+   +------------+   +------------+   +------------+
+	|                 |               |                |
+	+-----------+     |               |     +----------+
+		    |     |               |     |
+		+----------------------------------+
+		|           Multiplexor            |
+		+----------------------------------+
+		    |   |           |           |  |
+	+---------+   |           |           |  ------------+
+	|             |           |           |              |
+    +----------+  +----------+  +----------+  +----------+ +----------+
+    |  Psock   |  |  Psock   |  |  Psock   |  |  Psock   | |  Psock   |
+    +----------+  +----------+  +----------+  +----------+ +----------+
+	|              |           |            |             |
+    +----------+  +----------+  +----------+  +----------+ +----------+
+    | TCP sock |  | TCP sock |  | TCP sock |  | TCP sock | | TCP sock |
+    +----------+  +----------+  +----------+  +----------+ +----------+
+
+KCM sockets
+===========
+
+The KCM sockets provide the user interface to the multiplexor. All the KCM sockets
+bound to a multiplexor are considered to have equivalent function, and I/O
+operations in different sockets may be done in parallel without the need for
+synchronization between threads in userspace.
+
+Multiplexor
+===========
+
+The multiplexor provides the message steering. In the transmit path, messages
+written on a KCM socket are sent atomically on an appropriate TCP socket.
+Similarly, in the receive path, messages are constructed on each TCP socket
+(Psock) and complete messages are steered to a KCM socket.
+
+TCP sockets & Psocks
+====================
+
+TCP sockets may be bound to a KCM multiplexor. A Psock structure is allocated
+for each bound TCP socket, this structure holds the state for constructing
+messages on receive as well as other connection specific information for KCM.
+
+Connected mode semantics
+========================
+
+Each multiplexor assumes that all attached TCP connections are to the same
+destination and can use the different connections for load balancing when
+transmitting. The normal send and recv calls (include sendmmsg and recvmmsg)
+can be used to send and receive messages from the KCM socket.
+
+Socket types
+============
+
+KCM supports SOCK_DGRAM and SOCK_SEQPACKET socket types.
+
+Message delineation
+-------------------
+
+Messages are sent over a TCP stream with some application protocol message
+format that typically includes a header which frames the messages. The length
+of a received message can be deduced from the application protocol header
+(often just a simple length field).
+
+A TCP stream must be parsed to determine message boundaries. Berkeley Packet
+Filter (BPF) is used for this. When attaching a TCP socket to a multiplexor a
+BPF program must be specified. The program is called at the start of receiving
+a new message and is given an skbuff that contains the bytes received so far.
+It parses the message header and returns the length of the message. Given this
+information, KCM will construct the message of the stated length and deliver it
+to a KCM socket.
+
+TCP socket management
+---------------------
+
+When a TCP socket is attached to a KCM multiplexor data ready (POLLIN) and
+write space available (POLLOUT) events are handled by the multiplexor. If there
+is a state change (disconnection) or other error on a TCP socket, an error is
+posted on the TCP socket so that a POLLERR event happens and KCM discontinues
+using the socket. When the application gets the error notification for a
+TCP socket, it should unattach the socket from KCM and then handle the error
+condition (the typical response is to close the socket and create a new
+connection if necessary).
+
+KCM limits the maximum receive message size to be the size of the receive
+socket buffer on the attached TCP socket (the socket buffer size can be set by
+SO_RCVBUF). If the length of a new message reported by the BPF program is
+greater than this limit a corresponding error (EMSGSIZE) is posted on the TCP
+socket. The BPF program may also enforce a maximum messages size and report an
+error when it is exceeded.
+
+A timeout may be set for assembling messages on a receive socket. The timeout
+value is taken from the receive timeout of the attached TCP socket (this is set
+by SO_RCVTIMEO). If the timer expires before assembly is complete an error
+(ETIMEDOUT) is posted on the socket.
+
+User interface
+==============
+
+Creating a multiplexor
+----------------------
+
+A new multiplexor and initial KCM socket is created by a socket call::
+
+  socket(AF_KCM, type, protocol)
+
+- type is either SOCK_DGRAM or SOCK_SEQPACKET
+- protocol is KCMPROTO_CONNECTED
+
+Cloning KCM sockets
+-------------------
+
+After the first KCM socket is created using the socket call as described
+above, additional sockets for the multiplexor can be created by cloning
+a KCM socket. This is accomplished by an ioctl on a KCM socket::
+
+  /* From linux/kcm.h */
+  struct kcm_clone {
+	int fd;
+  };
+
+  struct kcm_clone info;
+
+  memset(&info, 0, sizeof(info));
+
+  err = ioctl(kcmfd, SIOCKCMCLONE, &info);
+
+  if (!err)
+    newkcmfd = info.fd;
+
+Attach transport sockets
+------------------------
+
+Attaching of transport sockets to a multiplexor is performed by calling an
+ioctl on a KCM socket for the multiplexor. e.g.::
+
+  /* From linux/kcm.h */
+  struct kcm_attach {
+	int fd;
+	int bpf_fd;
+  };
+
+  struct kcm_attach info;
+
+  memset(&info, 0, sizeof(info));
+
+  info.fd = tcpfd;
+  info.bpf_fd = bpf_prog_fd;
+
+  ioctl(kcmfd, SIOCKCMATTACH, &info);
+
+The kcm_attach structure contains:
+
+  - fd: file descriptor for TCP socket being attached
+  - bpf_prog_fd: file descriptor for compiled BPF program downloaded
+
+Unattach transport sockets
+--------------------------
+
+Unattaching a transport socket from a multiplexor is straightforward. An
+"unattach" ioctl is done with the kcm_unattach structure as the argument::
+
+  /* From linux/kcm.h */
+  struct kcm_unattach {
+	int fd;
+  };
+
+  struct kcm_unattach info;
+
+  memset(&info, 0, sizeof(info));
+
+  info.fd = cfd;
+
+  ioctl(fd, SIOCKCMUNATTACH, &info);
+
+Disabling receive on KCM socket
+-------------------------------
+
+A setsockopt is used to disable or enable receiving on a KCM socket.
+When receive is disabled, any pending messages in the socket's
+receive buffer are moved to other sockets. This feature is useful
+if an application thread knows that it will be doing a lot of
+work on a request and won't be able to service new messages for a
+while. Example use::
+
+  int val = 1;
+
+  setsockopt(kcmfd, SOL_KCM, KCM_RECV_DISABLE, &val, sizeof(val))
+
+BFP programs for message delineation
+------------------------------------
+
+BPF programs can be compiled using the BPF LLVM backend. For example,
+the BPF program for parsing Thrift is::
+
+  #include "bpf.h" /* for __sk_buff */
+  #include "bpf_helpers.h" /* for load_word intrinsic */
+
+  SEC("socket_kcm")
+  int bpf_prog1(struct __sk_buff *skb)
+  {
+       return load_word(skb, 0) + 4;
+  }
+
+  char _license[] SEC("license") = "GPL";
+
+Use in applications
+===================
+
+KCM accelerates application layer protocols. Specifically, it allows
+applications to use a message based interface for sending and receiving
+messages. The kernel provides necessary assurances that messages are sent
+and received atomically. This relieves much of the burden applications have
+in mapping a message based protocol onto the TCP stream. KCM also make
+application layer messages a unit of work in the kernel for the purposes of
+steering and scheduling, which in turn allows a simpler networking model in
+multithreaded applications.
+
+Configurations
+--------------
+
+In an Nx1 configuration, KCM logically provides multiple socket handles
+to the same TCP connection. This allows parallelism between in I/O
+operations on the TCP socket (for instance copyin and copyout of data is
+parallelized). In an application, a KCM socket can be opened for each
+processing thread and inserted into the epoll (similar to how SO_REUSEPORT
+is used to allow multiple listener sockets on the same port).
+
+In a MxN configuration, multiple connections are established to the
+same destination. These are used for simple load balancing.
+
+Message batching
+----------------
+
+The primary purpose of KCM is load balancing between KCM sockets and hence
+threads in a nominal use case. Perfect load balancing, that is steering
+each received message to a different KCM socket or steering each sent
+message to a different TCP socket, can negatively impact performance
+since this doesn't allow for affinities to be established. Balancing
+based on groups, or batches of messages, can be beneficial for performance.
+
+On transmit, there are three ways an application can batch (pipeline)
+messages on a KCM socket.
+
+  1) Send multiple messages in a single sendmmsg.
+  2) Send a group of messages each with a sendmsg call, where all messages
+     except the last have MSG_BATCH in the flags of sendmsg call.
+  3) Create "super message" composed of multiple messages and send this
+     with a single sendmsg.
+
+On receive, the KCM module attempts to queue messages received on the
+same KCM socket during each TCP ready callback. The targeted KCM socket
+changes at each receive ready callback on the KCM socket. The application
+does not need to configure this.
+
+Error handling
+--------------
+
+An application should include a thread to monitor errors raised on
+the TCP connection. Normally, this will be done by placing each
+TCP socket attached to a KCM multiplexor in epoll set for POLLERR
+event. If an error occurs on an attached TCP socket, KCM sets an EPIPE
+on the socket thus waking up the application thread. When the application
+sees the error (which may just be a disconnect) it should unattach the
+socket from KCM and then close it. It is assumed that once an error is
+posted on the TCP socket the data stream is unrecoverable (i.e. an error
+may have occurred in the middle of receiving a message).
+
+TCP connection monitoring
+-------------------------
+
+In KCM there is no means to correlate a message to the TCP socket that
+was used to send or receive the message (except in the case there is
+only one attached TCP socket). However, the application does retain
+an open file descriptor to the socket so it will be able to get statistics
+from the socket which can be used in detecting issues (such as high
+retransmissions on the socket).