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, 332 insertions, 0 deletions

diff --git a/Documentation/userspace-api/unshare.rst b/Documentation/userspace-api/unshare.rst
new file mode 100644
index 000000000..877e90a35
--- /dev/null
+++ b/Documentation/userspace-api/unshare.rst
@@ -0,0 +1,332 @@
+unshare system call
+===================
+
+This document describes the new system call, unshare(). The document
+provides an overview of the feature, why it is needed, how it can
+be used, its interface specification, design, implementation and
+how it can be tested.
+
+Change Log
+----------
+version 0.1  Initial document, Janak Desai (janak@us.ibm.com), Jan 11, 2006
+
+Contents
+--------
+	1) Overview
+	2) Benefits
+	3) Cost
+	4) Requirements
+	5) Functional Specification
+	6) High Level Design
+	7) Low Level Design
+	8) Test Specification
+	9) Future Work
+
+1) Overview
+-----------
+
+Most legacy operating system kernels support an abstraction of threads
+as multiple execution contexts within a process. These kernels provide
+special resources and mechanisms to maintain these "threads". The Linux
+kernel, in a clever and simple manner, does not make distinction
+between processes and "threads". The kernel allows processes to share
+resources and thus they can achieve legacy "threads" behavior without
+requiring additional data structures and mechanisms in the kernel. The
+power of implementing threads in this manner comes not only from
+its simplicity but also from allowing application programmers to work
+outside the confinement of all-or-nothing shared resources of legacy
+threads. On Linux, at the time of thread creation using the clone system
+call, applications can selectively choose which resources to share
+between threads.
+
+unshare() system call adds a primitive to the Linux thread model that
+allows threads to selectively 'unshare' any resources that were being
+shared at the time of their creation. unshare() was conceptualized by
+Al Viro in the August of 2000, on the Linux-Kernel mailing list, as part
+of the discussion on POSIX threads on Linux.  unshare() augments the
+usefulness of Linux threads for applications that would like to control
+shared resources without creating a new process. unshare() is a natural
+addition to the set of available primitives on Linux that implement
+the concept of process/thread as a virtual machine.
+
+2) Benefits
+-----------
+
+unshare() would be useful to large application frameworks such as PAM
+where creating a new process to control sharing/unsharing of process
+resources is not possible. Since namespaces are shared by default
+when creating a new process using fork or clone, unshare() can benefit
+even non-threaded applications if they have a need to disassociate
+from default shared namespace. The following lists two use-cases
+where unshare() can be used.
+
+2.1 Per-security context namespaces
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+unshare() can be used to implement polyinstantiated directories using
+the kernel's per-process namespace mechanism. Polyinstantiated directories,
+such as per-user and/or per-security context instance of /tmp, /var/tmp or
+per-security context instance of a user's home directory, isolate user
+processes when working with these directories. Using unshare(), a PAM
+module can easily setup a private namespace for a user at login.
+Polyinstantiated directories are required for Common Criteria certification
+with Labeled System Protection Profile, however, with the availability
+of shared-tree feature in the Linux kernel, even regular Linux systems
+can benefit from setting up private namespaces at login and
+polyinstantiating /tmp, /var/tmp and other directories deemed
+appropriate by system administrators.
+
+2.2 unsharing of virtual memory and/or open files
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Consider a client/server application where the server is processing
+client requests by creating processes that share resources such as
+virtual memory and open files. Without unshare(), the server has to
+decide what needs to be shared at the time of creating the process
+which services the request. unshare() allows the server an ability to
+disassociate parts of the context during the servicing of the
+request. For large and complex middleware application frameworks, this
+ability to unshare() after the process was created can be very
+useful.
+
+3) Cost
+-------
+
+In order to not duplicate code and to handle the fact that unshare()
+works on an active task (as opposed to clone/fork working on a newly
+allocated inactive task) unshare() had to make minor reorganizational
+changes to copy_* functions utilized by clone/fork system call.
+There is a cost associated with altering existing, well tested and
+stable code to implement a new feature that may not get exercised
+extensively in the beginning. However, with proper design and code
+review of the changes and creation of an unshare() test for the LTP
+the benefits of this new feature can exceed its cost.
+
+4) Requirements
+---------------
+
+unshare() reverses sharing that was done using clone(2) system call,
+so unshare() should have a similar interface as clone(2). That is,
+since flags in clone(int flags, void \*stack) specifies what should
+be shared, similar flags in unshare(int flags) should specify
+what should be unshared. Unfortunately, this may appear to invert
+the meaning of the flags from the way they are used in clone(2).
+However, there was no easy solution that was less confusing and that
+allowed incremental context unsharing in future without an ABI change.
+
+unshare() interface should accommodate possible future addition of
+new context flags without requiring a rebuild of old applications.
+If and when new context flags are added, unshare() design should allow
+incremental unsharing of those resources on an as needed basis.
+
+5) Functional Specification
+---------------------------
+
+NAME
+	unshare - disassociate parts of the process execution context
+
+SYNOPSIS
+	#include <sched.h>
+
+	int unshare(int flags);
+
+DESCRIPTION
+	unshare() allows a process to disassociate parts of its execution
+	context that are currently being shared with other processes. Part
+	of execution context, such as the namespace, is shared by default
+	when a new process is created using fork(2), while other parts,
+	such as the virtual memory, open file descriptors, etc, may be
+	shared by explicit request to share them when creating a process
+	using clone(2).
+
+	The main use of unshare() is to allow a process to control its
+	shared execution context without creating a new process.
+
+	The flags argument specifies one or bitwise-or'ed of several of
+	the following constants.
+
+	CLONE_FS
+		If CLONE_FS is set, file system information of the caller
+		is disassociated from the shared file system information.
+
+	CLONE_FILES
+		If CLONE_FILES is set, the file descriptor table of the
+		caller is disassociated from the shared file descriptor
+		table.
+
+	CLONE_NEWNS
+		If CLONE_NEWNS is set, the namespace of the caller is
+		disassociated from the shared namespace.
+
+	CLONE_VM
+		If CLONE_VM is set, the virtual memory of the caller is
+		disassociated from the shared virtual memory.
+
+RETURN VALUE
+	On success, zero returned. On failure, -1 is returned and errno is
+
+ERRORS
+	EPERM	CLONE_NEWNS was specified by a non-root process (process
+		without CAP_SYS_ADMIN).
+
+	ENOMEM	Cannot allocate sufficient memory to copy parts of caller's
+		context that need to be unshared.
+
+	EINVAL	Invalid flag was specified as an argument.
+
+CONFORMING TO
+	The unshare() call is Linux-specific and  should  not be used
+	in programs intended to be portable.
+
+SEE ALSO
+	clone(2), fork(2)
+
+6) High Level Design
+--------------------
+
+Depending on the flags argument, the unshare() system call allocates
+appropriate process context structures, populates it with values from
+the current shared version, associates newly duplicated structures
+with the current task structure and releases corresponding shared
+versions. Helper functions of clone (copy_*) could not be used
+directly by unshare() because of the following two reasons.
+
+  1) clone operates on a newly allocated not-yet-active task
+     structure, where as unshare() operates on the current active
+     task. Therefore unshare() has to take appropriate task_lock()
+     before associating newly duplicated context structures
+
+  2) unshare() has to allocate and duplicate all context structures
+     that are being unshared, before associating them with the
+     current task and releasing older shared structures. Failure
+     do so will create race conditions and/or oops when trying
+     to backout due to an error. Consider the case of unsharing
+     both virtual memory and namespace. After successfully unsharing
+     vm, if the system call encounters an error while allocating
+     new namespace structure, the error return code will have to
+     reverse the unsharing of vm. As part of the reversal the
+     system call will have to go back to older, shared, vm
+     structure, which may not exist anymore.
+
+Therefore code from copy_* functions that allocated and duplicated
+current context structure was moved into new dup_* functions. Now,
+copy_* functions call dup_* functions to allocate and duplicate
+appropriate context structures and then associate them with the
+task structure that is being constructed. unshare() system call on
+the other hand performs the following:
+
+  1) Check flags to force missing, but implied, flags
+
+  2) For each context structure, call the corresponding unshare()
+     helper function to allocate and duplicate a new context
+     structure, if the appropriate bit is set in the flags argument.
+
+  3) If there is no error in allocation and duplication and there
+     are new context structures then lock the current task structure,
+     associate new context structures with the current task structure,
+     and release the lock on the current task structure.
+
+  4) Appropriately release older, shared, context structures.
+
+7) Low Level Design
+-------------------
+
+Implementation of unshare() can be grouped in the following 4 different
+items:
+
+  a) Reorganization of existing copy_* functions
+
+  b) unshare() system call service function
+
+  c) unshare() helper functions for each different process context
+
+  d) Registration of system call number for different architectures
+
+7.1) Reorganization of copy_* functions
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Each copy function such as copy_mm, copy_namespace, copy_files,
+etc, had roughly two components. The first component allocated
+and duplicated the appropriate structure and the second component
+linked it to the task structure passed in as an argument to the copy
+function. The first component was split into its own function.
+These dup_* functions allocated and duplicated the appropriate
+context structure. The reorganized copy_* functions invoked
+their corresponding dup_* functions and then linked the newly
+duplicated structures to the task structure with which the
+copy function was called.
+
+7.2) unshare() system call service function
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+       * Check flags
+	 Force implied flags. If CLONE_THREAD is set force CLONE_VM.
+	 If CLONE_VM is set, force CLONE_SIGHAND. If CLONE_SIGHAND is
+	 set and signals are also being shared, force CLONE_THREAD. If
+	 CLONE_NEWNS is set, force CLONE_FS.
+
+       * For each context flag, invoke the corresponding unshare_*
+	 helper routine with flags passed into the system call and a
+	 reference to pointer pointing the new unshared structure
+
+       * If any new structures are created by unshare_* helper
+	 functions, take the task_lock() on the current task,
+	 modify appropriate context pointers, and release the
+         task lock.
+
+       * For all newly unshared structures, release the corresponding
+         older, shared, structures.
+
+7.3) unshare_* helper functions
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+For unshare_* helpers corresponding to CLONE_SYSVSEM, CLONE_SIGHAND,
+and CLONE_THREAD, return -EINVAL since they are not implemented yet.
+For others, check the flag value to see if the unsharing is
+required for that structure. If it is, invoke the corresponding
+dup_* function to allocate and duplicate the structure and return
+a pointer to it.
+
+7.4) Finally
+~~~~~~~~~~~~
+
+Appropriately modify architecture specific code to register the
+new system call.
+
+8) Test Specification
+---------------------
+
+The test for unshare() should test the following:
+
+  1) Valid flags: Test to check that clone flags for signal and
+     signal handlers, for which unsharing is not implemented
+     yet, return -EINVAL.
+
+  2) Missing/implied flags: Test to make sure that if unsharing
+     namespace without specifying unsharing of filesystem, correctly
+     unshares both namespace and filesystem information.
+
+  3) For each of the four (namespace, filesystem, files and vm)
+     supported unsharing, verify that the system call correctly
+     unshares the appropriate structure. Verify that unsharing
+     them individually as well as in combination with each
+     other works as expected.
+
+  4) Concurrent execution: Use shared memory segments and futex on
+     an address in the shm segment to synchronize execution of
+     about 10 threads. Have a couple of threads execute execve,
+     a couple _exit and the rest unshare with different combination
+     of flags. Verify that unsharing is performed as expected and
+     that there are no oops or hangs.
+
+9) Future Work
+--------------
+
+The current implementation of unshare() does not allow unsharing of
+signals and signal handlers. Signals are complex to begin with and
+to unshare signals and/or signal handlers of a currently running
+process is even more complex. If in the future there is a specific
+need to allow unsharing of signals and/or signal handlers, it can
+be incrementally added to unshare() without affecting legacy
+applications using unshare().
+