Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next

Pull networking updates from David Miller:

 1) Support IPV6 RA Captive Portal Identifier, from Maciej Żenczykowski.

 2) Use bio_vec in the networking instead of custom skb_frag_t, from
    Matthew Wilcox.

 3) Make use of xmit_more in r8169 driver, from Heiner Kallweit.

 4) Add devmap_hash to xdp, from Toke Høiland-Jørgensen.

 5) Support all variants of 5750X bnxt_en chips, from Michael Chan.

 6) More RTNL avoidance work in the core and mlx5 driver, from Vlad
    Buslov.

 7) Add TCP syn cookies bpf helper, from Petar Penkov.

 8) Add 'nettest' to selftests and use it, from David Ahern.

 9) Add extack support to drop_monitor, add packet alert mode and
    support for HW drops, from Ido Schimmel.

10) Add VLAN offload to stmmac, from Jose Abreu.

11) Lots of devm_platform_ioremap_resource() conversions, from
    YueHaibing.

12) Add IONIC driver, from Shannon Nelson.

13) Several kTLS cleanups, from Jakub Kicinski.

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1930 commits)
  mlxsw: spectrum_buffers: Add the ability to query the CPU port's shared buffer
  mlxsw: spectrum: Register CPU port with devlink
  mlxsw: spectrum_buffers: Prevent changing CPU port's configuration
  net: ena: fix incorrect update of intr_delay_resolution
  net: ena: fix retrieval of nonadaptive interrupt moderation intervals
  net: ena: fix update of interrupt moderation register
  net: ena: remove all old adaptive rx interrupt moderation code from ena_com
  net: ena: remove ena_restore_ethtool_params() and relevant fields
  net: ena: remove old adaptive interrupt moderation code from ena_netdev
  net: ena: remove code duplication in ena_com_update_nonadaptive_moderation_interval _*()
  net: ena: enable the interrupt_moderation in driver_supported_features
  net: ena: reimplement set/get_coalesce()
  net: ena: switch to dim algorithm for rx adaptive interrupt moderation
  net: ena: add intr_moder_rx_interval to struct ena_com_dev and use it
  net: phy: adin: implement Energy Detect Powerdown mode via phy-tunable
  ethtool: implement Energy Detect Powerdown support via phy-tunable
  xen-netfront: do not assume sk_buff_head list is empty in error handling
  s390/ctcm: Delete unnecessary checks before the macro call “dev_kfree_skb”
  net: ena: don't wake up tx queue when down
  drop_monitor: Better sanitize notified packets
  ...

1 files changed, 208 insertions, 0 deletions

diff --git a/Documentation/networking/devlink-trap.rst b/Documentation/networking/devlink-trap.rst
new file mode 100644
index 000000000000..c20c7c483664
--- /dev/null
+++ b/Documentation/networking/devlink-trap.rst
@@ -0,0 +1,208 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+============
+Devlink Trap
+============
+
+Background
+==========
+
+Devices capable of offloading the kernel's datapath and perform functions such
+as bridging and routing must also be able to send specific packets to the
+kernel (i.e., the CPU) for processing.
+
+For example, a device acting as a multicast-aware bridge must be able to send
+IGMP membership reports to the kernel for processing by the bridge module.
+Without processing such packets, the bridge module could never populate its
+MDB.
+
+As another example, consider a device acting as router which has received an IP
+packet with a TTL of 1. Upon routing the packet the device must send it to the
+kernel so that it will route it as well and generate an ICMP Time Exceeded
+error datagram. Without letting the kernel route such packets itself, utilities
+such as ``traceroute`` could never work.
+
+The fundamental ability of sending certain packets to the kernel for processing
+is called "packet trapping".
+
+Overview
+========
+
+The ``devlink-trap`` mechanism allows capable device drivers to register their
+supported packet traps with ``devlink`` and report trapped packets to
+``devlink`` for further analysis.
+
+Upon receiving trapped packets, ``devlink`` will perform a per-trap packets and
+bytes accounting and potentially report the packet to user space via a netlink
+event along with all the provided metadata (e.g., trap reason, timestamp, input
+port). This is especially useful for drop traps (see :ref:`Trap-Types`)
+as it allows users to obtain further visibility into packet drops that would
+otherwise be invisible.
+
+The following diagram provides a general overview of ``devlink-trap``::
+
+                                    Netlink event: Packet w/ metadata
+                                                   Or a summary of recent drops
+                                  ^
+                                  |
+         Userspace                |
+        +---------------------------------------------------+
+         Kernel                   |
+                                  |
+                          +-------+--------+
+                          |                |
+                          |  drop_monitor  |
+                          |                |
+                          +-------^--------+
+                                  |
+                                  |
+                                  |
+                             +----+----+
+                             |         |      Kernel's Rx path
+                             | devlink |      (non-drop traps)
+                             |         |
+                             +----^----+      ^
+                                  |           |
+                                  +-----------+
+                                  |
+                          +-------+-------+
+                          |               |
+                          | Device driver |
+                          |               |
+                          +-------^-------+
+         Kernel                   |
+        +---------------------------------------------------+
+         Hardware                 |
+                                  | Trapped packet
+                                  |
+                               +--+---+
+                               |      |
+                               | ASIC |
+                               |      |
+                               +------+
+
+.. _Trap-Types:
+
+Trap Types
+==========
+
+The ``devlink-trap`` mechanism supports the following packet trap types:
+
+  * ``drop``: Trapped packets were dropped by the underlying device. Packets
+    are only processed by ``devlink`` and not injected to the kernel's Rx path.
+    The trap action (see :ref:`Trap-Actions`) can be changed.
+  * ``exception``: Trapped packets were not forwarded as intended by the
+    underlying device due to an exception (e.g., TTL error, missing neighbour
+    entry) and trapped to the control plane for resolution. Packets are
+    processed by ``devlink`` and injected to the kernel's Rx path. Changing the
+    action of such traps is not allowed, as it can easily break the control
+    plane.
+
+.. _Trap-Actions:
+
+Trap Actions
+============
+
+The ``devlink-trap`` mechanism supports the following packet trap actions:
+
+  * ``trap``: The sole copy of the packet is sent to the CPU.
+  * ``drop``: The packet is dropped by the underlying device and a copy is not
+    sent to the CPU.
+
+Generic Packet Traps
+====================
+
+Generic packet traps are used to describe traps that trap well-defined packets
+or packets that are trapped due to well-defined conditions (e.g., TTL error).
+Such traps can be shared by multiple device drivers and their description must
+be added to the following table:
+
+.. list-table:: List of Generic Packet Traps
+   :widths: 5 5 90
+
+   * - Name
+     - Type
+     - Description
+   * - ``source_mac_is_multicast``
+     - ``drop``
+     - Traps incoming packets that the device decided to drop because of a
+       multicast source MAC
+   * - ``vlan_tag_mismatch``
+     - ``drop``
+     - Traps incoming packets that the device decided to drop in case of VLAN
+       tag mismatch: The ingress bridge port is not configured with a PVID and
+       the packet is untagged or prio-tagged
+   * - ``ingress_vlan_filter``
+     - ``drop``
+     - Traps incoming packets that the device decided to drop in case they are
+       tagged with a VLAN that is not configured on the ingress bridge port
+   * - ``ingress_spanning_tree_filter``
+     - ``drop``
+     - Traps incoming packets that the device decided to drop in case the STP
+       state of the ingress bridge port is not "forwarding"
+   * - ``port_list_is_empty``
+     - ``drop``
+     - Traps packets that the device decided to drop in case they need to be
+       flooded and the flood list is empty
+   * - ``port_loopback_filter``
+     - ``drop``
+     - Traps packets that the device decided to drop in case after layer 2
+       forwarding the only port from which they should be transmitted through
+       is the port from which they were received
+   * - ``blackhole_route``
+     - ``drop``
+     - Traps packets that the device decided to drop in case they hit a
+       blackhole route
+   * - ``ttl_value_is_too_small``
+     - ``exception``
+     - Traps unicast packets that should be forwarded by the device whose TTL
+       was decremented to 0 or less
+   * - ``tail_drop``
+     - ``drop``
+     - Traps packets that the device decided to drop because they could not be
+       enqueued to a transmission queue which is full
+
+Driver-specific Packet Traps
+============================
+
+Device drivers can register driver-specific packet traps, but these must be
+clearly documented. Such traps can correspond to device-specific exceptions and
+help debug packet drops caused by these exceptions. The following list includes
+links to the description of driver-specific traps registered by various device
+drivers:
+
+  * :doc:`/devlink-trap-netdevsim`
+
+Generic Packet Trap Groups
+==========================
+
+Generic packet trap groups are used to aggregate logically related packet
+traps. These groups allow the user to batch operations such as setting the trap
+action of all member traps. In addition, ``devlink-trap`` can report aggregated
+per-group packets and bytes statistics, in case per-trap statistics are too
+narrow. The description of these groups must be added to the following table:
+
+.. list-table:: List of Generic Packet Trap Groups
+   :widths: 10 90
+
+   * - Name
+     - Description
+   * - ``l2_drops``
+     - Contains packet traps for packets that were dropped by the device during
+       layer 2 forwarding (i.e., bridge)
+   * - ``l3_drops``
+     - Contains packet traps for packets that were dropped by the device or hit
+       an exception (e.g., TTL error) during layer 3 forwarding
+   * - ``buffer_drops``
+     - Contains packet traps for packets that were dropped by the device due to
+       an enqueue decision
+
+Testing
+=======
+
+See ``tools/testing/selftests/drivers/net/netdevsim/devlink_trap.sh`` for a
+test covering the core infrastructure. Test cases should be added for any new
+functionality.
+
+Device drivers should focus their tests on device-specific functionality, such
+as the triggering of supported packet traps.