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, 149 insertions, 0 deletions

diff --git a/Documentation/networking/fib_trie.rst b/Documentation/networking/fib_trie.rst
new file mode 100644
index 000000000..f1435b7fc
--- /dev/null
+++ b/Documentation/networking/fib_trie.rst
@@ -0,0 +1,149 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+============================
+LC-trie implementation notes
+============================
+
+Node types
+----------
+leaf
+	An end node with data. This has a copy of the relevant key, along
+	with 'hlist' with routing table entries sorted by prefix length.
+	See struct leaf and struct leaf_info.
+
+trie node or tnode
+	An internal node, holding an array of child (leaf or tnode) pointers,
+	indexed	through a subset of the key. See Level Compression.
+
+A few concepts explained
+------------------------
+Bits (tnode)
+	The number of bits in the key segment used for indexing into the
+	child array - the "child index". See Level Compression.
+
+Pos (tnode)
+	The position (in the key) of the key segment used for indexing into
+	the child array. See Path Compression.
+
+Path Compression / skipped bits
+	Any given tnode is linked to from the child array of its parent, using
+	a segment of the key specified by the parent's "pos" and "bits"
+	In certain cases, this tnode's own "pos" will not be immediately
+	adjacent to the parent (pos+bits), but there will be some bits
+	in the key skipped over because they represent a single path with no
+	deviations. These "skipped bits" constitute Path Compression.
+	Note that the search algorithm will simply skip over these bits when
+	searching, making it necessary to save the keys in the leaves to
+	verify that they actually do match the key we are searching for.
+
+Level Compression / child arrays
+	the trie is kept level balanced moving, under certain conditions, the
+	children of a full child (see "full_children") up one level, so that
+	instead of a pure binary tree, each internal node ("tnode") may
+	contain an arbitrarily large array of links to several children.
+	Conversely, a tnode with a mostly empty	child array (see empty_children)
+	may be "halved", having some of its children moved downwards one level,
+	in order to avoid ever-increasing child arrays.
+
+empty_children
+	the number of positions in the child array of a given tnode that are
+	NULL.
+
+full_children
+	the number of children of a given tnode that aren't path compressed.
+	(in other words, they aren't NULL or leaves and their "pos" is equal
+	to this	tnode's "pos"+"bits").
+
+	(The word "full" here is used more in the sense of "complete" than
+	as the opposite of "empty", which might be a tad confusing.)
+
+Comments
+---------
+
+We have tried to keep the structure of the code as close to fib_hash as
+possible to allow verification and help up reviewing.
+
+fib_find_node()
+	A good start for understanding this code. This function implements a
+	straightforward trie lookup.
+
+fib_insert_node()
+	Inserts a new leaf node in the trie. This is bit more complicated than
+	fib_find_node(). Inserting a new node means we might have to run the
+	level compression algorithm on part of the trie.
+
+trie_leaf_remove()
+	Looks up a key, deletes it and runs the level compression algorithm.
+
+trie_rebalance()
+	The key function for the dynamic trie after any change in the trie
+	it is run to optimize and reorganize. It will walk the trie upwards
+	towards the root from a given tnode, doing a resize() at each step
+	to implement level compression.
+
+resize()
+	Analyzes a tnode and optimizes the child array size by either inflating
+	or shrinking it repeatedly until it fulfills the criteria for optimal
+	level compression. This part follows the original paper pretty closely
+	and there may be some room for experimentation here.
+
+inflate()
+	Doubles the size of the child array within a tnode. Used by resize().
+
+halve()
+	Halves the size of the child array within a tnode - the inverse of
+	inflate(). Used by resize();
+
+fn_trie_insert(), fn_trie_delete(), fn_trie_select_default()
+	The route manipulation functions. Should conform pretty closely to the
+	corresponding functions in fib_hash.
+
+fn_trie_flush()
+	This walks the full trie (using nextleaf()) and searches for empty
+	leaves which have to be removed.
+
+fn_trie_dump()
+	Dumps the routing table ordered by prefix length. This is somewhat
+	slower than the corresponding fib_hash function, as we have to walk the
+	entire trie for each prefix length. In comparison, fib_hash is organized
+	as one "zone"/hash per prefix length.
+
+Locking
+-------
+
+fib_lock is used for an RW-lock in the same way that this is done in fib_hash.
+However, the functions are somewhat separated for other possible locking
+scenarios. It might conceivably be possible to run trie_rebalance via RCU
+to avoid read_lock in the fn_trie_lookup() function.
+
+Main lookup mechanism
+---------------------
+fn_trie_lookup() is the main lookup function.
+
+The lookup is in its simplest form just like fib_find_node(). We descend the
+trie, key segment by key segment, until we find a leaf. check_leaf() does
+the fib_semantic_match in the leaf's sorted prefix hlist.
+
+If we find a match, we are done.
+
+If we don't find a match, we enter prefix matching mode. The prefix length,
+starting out at the same as the key length, is reduced one step at a time,
+and we backtrack upwards through the trie trying to find a longest matching
+prefix. The goal is always to reach a leaf and get a positive result from the
+fib_semantic_match mechanism.
+
+Inside each tnode, the search for longest matching prefix consists of searching
+through the child array, chopping off (zeroing) the least significant "1" of
+the child index until we find a match or the child index consists of nothing but
+zeros.
+
+At this point we backtrack (t->stats.backtrack++) up the trie, continuing to
+chop off part of the key in order to find the longest matching prefix.
+
+At this point we will repeatedly descend subtries to look for a match, and there
+are some optimizations available that can provide us with "shortcuts" to avoid
+descending into dead ends. Look for "HL_OPTIMIZE" sections in the code.
+
+To alleviate any doubts about the correctness of the route selection process,
+a new netlink operation has been added. Look for NETLINK_FIB_LOOKUP, which
+gives userland access to fib_lookup().