Lines Matching +full:in +full:- +full:ports
8 in joining the effort.
22 An Ethernet switch typically comprises multiple front-panel ports and one
23 or more CPU or management ports. The DSA subsystem currently relies on the
26 kinds of Ethernet switches found in Small Home and Office products: routers,
27 gateways, or even top-of-rack switches. This host Ethernet controller will
28 be later referred to as "conduit" and "cpu" in DSA terminology and code.
30 The D in DSA stands for Distributed, because the subsystem has been designed
33 ports are referred to as "dsa" ports in DSA terminology and code. A collection
36 For each front-panel port, DSA creates specialized network devices which are
37 used as controlling and data-flowing endpoints for use by the Linux networking
39 interfaces in DSA terminology and code.
43 Ethernet frame it receives to/from specific ports to help the management
46 - what port is this frame coming from
47 - what was the reason why this frame got forwarded
48 - how to send CPU originated traffic to specific ports
51 the features might be slightly limited in that case (traffic separation relies
52 on Port-based VLAN IDs).
55 "dsa" ports because:
57 - the "cpu" port is the Ethernet switch facing side of the management
61 - the "dsa" port(s) are just conduits between two or more switches, and as such
63 downstream, or the top-most upstream interface makes sense with that model
70 ------------------------
72 DSA supports many vendor-specific tagging protocols, one software-defined
73 tagging protocol, and a tag-less mode as well (``DSA_TAG_PROTO_NONE``).
75 The exact format of the tag protocol is vendor specific, but in general, they
78 - identifies which port the Ethernet frame came from/should be sent to
79 - provides a reason why this frame was forwarded to the management interface
81 All tagging protocols are in ``net/dsa/tag_*.c`` files and implement the
84 Tagging protocols generally fall in one of three categories:
86 1. The switch-specific frame header is located before the Ethernet header,
89 2. The switch-specific frame header is located before the EtherType, keeping
90 the MAC DA and MAC SA in place from the DSA conduit's perspective, but
92 3. The switch-specific frame header is located at the tail of the packet,
93 keeping all frame headers in place and not altering the view of the packet
101 with the length in octets of the longest switch frame header/trailer. The DSA
103 accommodate for this extra size in order for DSA user ports to support the
106 on a best-effort basis, the allocation of packets with enough extra space such
110 Even though applications are not expected to parse DSA-specific frame headers,
121 switch tree use the same tagging protocol. In case of a packet transiting a
122 fabric with more than one switch, the switch-specific frame header is inserted
123 by the first switch in the fabric that the packet was received on. This header
127 data frames might also be autonomously forwarded towards other user ports of
128 other switches from the same fabric, and in this case, the outermost switch
129 ports must decapsulate the packet.
131 Note that in certain cases, it might be the case that the tagging format used
136 DSA frame header, in order to reduce the autonomous packet forwarding overhead.
138 EDSA tagging protocol, the operating system sees EDSA-tagged packets from the
145 tagging protocols are not compatible with one another. In this case, there are
146 no DSA links in this fabric, and each switch constitutes a disjoint DSA switch
147 tree. The DSA links are viewed as simply a pair of a DSA conduit (the out-facing
148 port of the upstream DSA switch) and a CPU port (the in-facing port of the
159 all attached switch ports must be down while doing this).
163 any network interface should be capable of transmitting the same packet in the
164 same way, and the tagger should decode the same received packet in the same way
169 The passed ``struct sk_buff *skb`` has ``skb->data`` pointing at
173 The job of this method is to prepare the skb in a way that the switch will
175 ports). Typically this is fulfilled by pushing a frame header. Checking for
176 insufficient size in the skb headroom or tailroom is unnecessary provided that
181 passed ``struct sk_buff *skb`` has ``skb->data`` pointing at
184 method is to consume the frame header, adjust ``skb->data`` to really point at
185 the first octet after the EtherType, and to change ``skb->dev`` to point to the
186 virtual DSA user network interface corresponding to the physical front-facing
189 Since tagging protocols in category 1 and 2 break software (and most often also
193 the IP header is to be found in the tagged frame as seen by the DSA conduit.
201 driver declares NETIF_F_HW_CSUM in vlan_features and looks at csum_start and
204 or NETIF_F_IPV6_CSUM in vlan_features, the offload might only work if the
206 vendors). DSA user ports inherit those flags from the conduit, and it is up to
211 already expect the switch tag in use, the checksum must be calculated before any
213 include the tail tag in the (software or hardware) checksum calculation. Then,
215 incorrect IP checksum in place.
218 with DSA-unaware conduits, mangling what the conduit perceives as MAC DA), the
219 tagging protocol may require the DSA conduit to operate in promiscuous mode, to
222 Note that this assumes a DSA-unaware conduit driver, which is the norm.
225 -----------------------
237 ----------------------
239 When a conduit netdev is used with DSA, a small hook is placed in the
240 networking stack is in order to have the DSA subsystem process the Ethernet
242 specific (and fake) Ethernet type (later becoming ``skb->protocol``) with the
250 - receive function is invoked
251 - basic packet processing is done: getting length, status etc.
252 - packet is prepared to be processed by the Ethernet layer by calling
258 if (dev->dsa_ptr != NULL)
259 -> skb->protocol = ETH_P_XDSA
264 -> iterate over registered packet_type
265 -> invoke handler for ETH_P_XDSA, calls dsa_switch_rcv()
269 -> dsa_switch_rcv()
270 -> invoke switch tag specific protocol handler in 'net/dsa/tag_*.c'
274 - inspect and strip switch tag protocol to determine originating port
275 - locate per-port network device
276 - invoke ``eth_type_trans()`` with the DSA user network device
277 - invoked ``netif_receive_skb()``
283 --------------------
287 controlling and data-flowing end-point for each front-panel port of the switch.
288 These interfaces are specialized in order to:
290 - insert/remove the switch tag protocol (if it exists) when sending traffic
291 to/from specific switch ports
292 - query the switch for ethtool operations: statistics, link state,
293 Wake-on-LAN, register dumps...
294 - manage external/internal PHY: link, auto-negotiation, etc.
303 switch tag in the Ethernet frames.
310 When using multiple CPU ports, it is possible to stack a LAG (bonding/team)
314 recovery in case the LAG DSA conduit disappears). Thus, the data path of the LAG
321 other, and in both cases, the packet exits the system through a hardware path
325 ------------------------
334 +-----------v--|--------------------+
335 |+------+ +------+ +------+ +------+|
337 |+------+-+------+-+------+-+------+|
339 +-----------------------------------+
344 +-----------------------------------+
346 --------+-----------------------------------+------------
348 +-----------------------------------+
353 +-----------------------------------+
355 |+------+ +------+ +------+ +------+|
357 ++------+-+------+-+------+-+------++
360 -------------
362 In order to be able to read to/from a switch PHY built into it, DSA creates an
364 MDIO reads/writes towards specific PHY addresses. In most MDIO-connected
367 library and/or to return link status, link partner pages, auto-negotiation
376 ---------------
378 DSA data structures are defined in ``include/net/dsa.h`` as well as
381 - ``dsa_chip_data``: platform data configuration for a given switch device,
383 well as various properties of its ports: names/labels, and finally a routing
386 - ``dsa_platform_data``: platform device configuration data which can reference
391 - ``dsa_switch_tree``: structure assigned to the conduit network device under
396 referenced to address individual switches in the tree.
398 - ``dsa_switch``: structure describing a switch device in the tree, referencing
402 - ``dsa_switch_ops``: structure referencing function pointers, see below for a
409 -------------------------------
411 DSA does not currently create user network devices for the CPU or DSA ports, as
412 described before. This might be an issue in the following cases:
414 - inability to fetch switch CPU port statistics counters using ethtool, which
417 - inability to configure the CPU port link parameters based on the Ethernet
420 - inability to configure specific VLAN IDs / trunking VLANs between switches
424 --------------------------------
426 Once a conduit network device is configured to use DSA (dev->dsa_ptr becomes
427 non-NULL), and the switch behind it expects a tagging protocol, this network
439 - MDIO/PHY library: ``drivers/net/phy/phy.c``, ``mdio_bus.c``
440 - Switchdev:``net/switchdev/*``
441 - Device Tree for various of_* functions
442 - Devlink: ``net/core/devlink.c``
445 ----------------
448 devices (``struct phy_device`` as defined in ``include/linux/phy.h)``, but the DSA
451 - internal PHY devices, built into the Ethernet switch hardware
452 - external PHY devices, connected via an internal or external MDIO bus
453 - internal PHY devices, connected via an internal MDIO bus
454 - special, non-autonegotiated or non MDIO-managed PHY devices: SFPs, MoCA; a.k.a
460 - if Device Tree is used, the PHY device is looked up using the standard
461 "phy-handle" property, if found, this PHY device is created and registered
464 - if Device Tree is used and the PHY device is "fixed", that is, conforms to
465 the definition of a non-MDIO managed PHY as defined in
466 ``Documentation/devicetree/bindings/net/fixed-link.txt``, the PHY is registered
469 - finally, if the PHY is built into the switch, as is very common with
475 ---------
479 of per-port user network devices. As of today, the only SWITCHDEV objects
483 -------
485 DSA registers one devlink device per physical switch in the fabric.
486 For each devlink device, every physical port (i.e. user ports, CPU ports, DSA
487 links or unused ports) is exposed as a devlink port.
491 - Regions: debugging feature which allows user space to dump driver-defined
492 areas of hardware information in a low-level, binary format. Both global
493 regions as well as per-port regions are supported. It is possible to export
494 devlink regions even for pieces of data that are already exposed in some way
495 to the standard iproute2 user space programs (ip-link, bridge), like address
497 contain additional hardware-specific details which are not visible through
499 the non-user ports too, which are invisible to iproute2 because no network
501 - Params: a feature which enables user to configure certain low-level tunable
503 devlink params, or may add new device-specific devlink params.
504 - Resources: a monitoring feature which enables users to see the degree of
505 utilization of certain hardware tables in the device, such as FDB, VLAN, etc.
506 - Shared buffers: a QoS feature for adjusting and partitioning memory and frame
507 reservations per port and per traffic class, in the ingress and egress
508 directions, such that low-priority bulk traffic does not impede the
509 processing of high-priority critical traffic.
514 -----------
516 DSA features a standardized binding which is documented in
519 per-port PHY specific details: interface connection, MDIO bus location, etc.
528 -----------------------------------------
531 I2C, MDIO or otherwise). The DSA framework is not involved in their probing
536 switch driver's probing function. The following members must be valid in the
539 - ``ds->dev``: will be used to parse the switch's OF node or platform data.
541 - ``ds->num_ports``: will be used to create the port list for this switch, and
542 to validate the port indices provided in the OF node.
544 - ``ds->ops``: a pointer to the ``dsa_switch_ops`` structure holding the DSA
547 - ``ds->priv``: backpointer to a driver-private data structure which can be
548 retrieved in all further DSA method callbacks.
550 In addition, the following flags in the ``dsa_switch`` structure may optionally
551 be configured to obtain driver-specific behavior from the DSA core. Their
552 behavior when set is documented through comments in ``include/net/dsa.h``.
554 - ``ds->vlan_filtering_is_global``
556 - ``ds->needs_standalone_vlan_filtering``
558 - ``ds->configure_vlan_while_not_filtering``
560 - ``ds->untag_bridge_pvid``
562 - ``ds->assisted_learning_on_cpu_port``
564 - ``ds->mtu_enforcement_ingress``
566 - ``ds->fdb_isolation``
577 In case of a tree with multiple switches, probing takes place asymmetrically.
578 The first N-1 callers of ``dsa_register_switch()`` only add their ports to the
579 port list of the tree (``dst->ports``), each port having a backpointer to its
580 associated switch (``dp->ds``). Then, these switches exit their
582 has determined that the tree is not yet complete (not all ports referenced by
583 DSA links are present in the tree's port list). The tree becomes complete when
585 continuation of initialization (including the call to ``ds->ops->setup()``) for
590 which removes a switch's ports from the port list of the tree. The entire tree
612 --------------------
614 - ``get_tag_protocol``: this is to indicate what kind of tagging protocol is
618 upstream switch, in case there are hardware limitations in terms of supported
621 - ``change_tag_protocol``: when the default tagging protocol has compatibility
623 at runtime, either through a device tree property or through sysfs. In that
624 case, further calls to ``get_tag_protocol`` should report the protocol in
627 - ``setup``: setup function for the switch, this function is responsible for setting
632 a Port-based VLAN ID for each port and allowing only the CPU port and the
633 specific port to be in the forwarding vector. Ports that are unused by the
636 to issue a software reset of the switch during this setup function in order to
641 - ``port_setup`` and ``port_teardown``: methods for initialization and
642 destruction of per-port data structures. It is mandatory for some operations
646 probing only to be torn down immediately afterwards, for example in case its
647 PHY cannot be found. In this case, probing of the DSA switch continues
650 - ``port_change_conduit``: method through which the affinity (association used
652 changed. By default all user ports from a tree are assigned to the first
654 the user ports of a tree are all assigned to the same CPU port, except for H
655 topologies as described in commit 2c0b03258b8b). The ``port`` argument
659 conduit->dsa_ptr``. Additionally, the conduit can also be a LAG device where
661 valid ``conduit->dsa_ptr`` pointer, however this is not unique, but rather a
662 duplicate of the first physical DSA conduit's (LAG slave) ``dsa_ptr``. In case
664 separately for the physical CPU ports associated with the physical DSA
669 -------------------------------
671 - ``get_phy_flags``: Some switches are interfaced to various kinds of Ethernet PHYs,
674 should return a 32-bit bitmask of "flags" that is private between the switch
675 driver and the Ethernet PHY driver in ``drivers/net/phy/\*``.
677 - ``phy_read``: Function invoked by the DSA user MDIO bus when attempting to read
680 status, auto-negotiation results, link partner pages, etc.
682 - ``phy_write``: Function invoked by the DSA user MDIO bus when attempting to write
686 - ``adjust_link``: Function invoked by the PHY library when a user network device
691 - ``fixed_link_update``: Function invoked by the PHY library, and specifically by
693 not be auto-negotiated, or obtained by reading the PHY registers through MDIO.
695 MoCA or other kinds of non-MDIO managed PHYs where out of band link
699 ------------------
701 - ``get_strings``: ethtool function used to query the driver's strings, will
704 - ``get_ethtool_stats``: ethtool function used to query per-port statistics and
709 - ``get_sset_count``: ethtool function used to query the number of statistics items
711 - ``get_wol``: ethtool function used to obtain Wake-on-LAN settings per-port, this
713 Wake-on-LAN settings if this interface needs to participate in Wake-on-LAN
715 - ``set_wol``: ethtool function used to configure Wake-on-LAN settings per-port,
718 - ``set_eee``: ethtool function which is used to configure a switch port EEE (Green
721 controller and data-processing logic
723 - ``get_eee``: ethtool function which is used to query a switch port EEE settings,
725 and data-processing logic as well as query the PHY for its currently configured
728 - ``get_eeprom_len``: ethtool function returning for a given switch the EEPROM
729 length/size in bytes
731 - ``get_eeprom``: ethtool function returning for a given switch the EEPROM contents
733 - ``set_eeprom``: ethtool function writing specified data to a given switch EEPROM
735 - ``get_regs_len``: ethtool function returning the register length for a given
738 - ``get_regs``: ethtool function returning the Ethernet switch internal register
739 contents. This function might require user-land code in ethtool to
740 pretty-print register values and registers
743 ----------------
745 - ``suspend``: function invoked by the DSA platform device when the system goes to
746 suspend, should quiesce all Ethernet switch activities, but keep ports
747 participating in Wake-on-LAN active as well as additional wake-up logic if
750 - ``resume``: function invoked by the DSA platform device when the system resumes,
751 should resume all Ethernet switch activities and re-configure the switch to be
752 in a fully active state
754 - ``port_enable``: function invoked by the DSA user network device ndo_open
760 - ``port_disable``: function invoked by the DSA user network device ndo_close
767 -----------------
773 occasionally be called "FID" (Filtering ID) in this document, although the
776 For example, all ports that belong to a VLAN-unaware bridge (which is
777 *currently* VLAN-unaware) are expected to learn source addresses in the
779 VLAN-unaware bridges). During forwarding and FDB lookup, a packet received on a
780 VLAN-unaware bridge port should be able to find a VLAN-unaware FDB entry having
784 a port which is a member of a different VLAN-unaware bridge (and is therefore
787 Similarly, each VLAN of each offloaded VLAN-aware bridge should have an
788 associated address database, which is shared by all ports which are members of
789 that VLAN, but not shared by ports belonging to different bridges that are
792 In this context, a VLAN-unaware database means that all packets are expected to
794 VLAN-aware database means that packets are supposed to match based on the VLAN
797 At the bridge layer, VLAN-unaware FDB entries have the special VID value of 0,
798 whereas VLAN-aware FDB entries have non-zero VID values. Note that a
799 VLAN-unaware bridge may have VLAN-aware (non-zero VID) FDB entries, and a
800 VLAN-aware bridge may have VLAN-unaware FDB entries. As in hardware, the
805 When a user port operates in standalone mode, its driver should configure it to
808 (packet in, packet out to the CPU port) as little as possible. For example,
812 database should be empty in a naive implementation, and in this case, all
815 DSA (cascade) and CPU ports are also called "shared" ports because they service
817 to is usually embedded in the DSA tag. This means that the CPU port may
819 classified by hardware in one address database), and from a bridge port (which
825 for which it is known that software is interested in those MAC addresses.
832 - Primary unicast MAC addresses of ports (``dev->dev_addr``). These are
837 - Secondary unicast and multicast MAC addresses of ports (addresses added
841 - Local/permanent bridge FDB entries (``BR_FDB_LOCAL``). These are the MAC
842 addresses of the bridge ports, for which packets must be terminated locally
846 - Static bridge FDB entries installed towards foreign (non-DSA) interfaces
847 present in the same bridge as some DSA switch ports. These are also
850 - Dynamically learned FDB entries on foreign interfaces present in the same
851 bridge as some DSA switch ports, only if ``ds->assisted_learning_on_cpu_port``
858 - ``DSA_DB_PORT``: the FDB (or MDB) entry to be installed or deleted belongs to
859 the port private database of user port ``db->dp``.
860 - ``DSA_DB_BRIDGE``: the entry belongs to one of the address databases of bridge
861 ``db->bridge``. Separation between the VLAN-unaware database and the per-VID
863 - ``DSA_DB_LAG``: the entry belongs to the address database of LAG ``db->lag``.
864 Note: ``DSA_DB_LAG`` is currently unused and may be removed in the future.
866 The drivers which act upon the ``dsa_db`` argument in ``port_fdb_add``,
867 ``port_mdb_add`` etc should declare ``ds->fdb_isolation`` as true.
869 DSA associates each offloaded bridge and each offloaded LAG with a one-based ID
871 refcounting addresses on shared ports. Drivers may piggyback on DSA's numbering
872 scheme (the ID is readable through ``db->bridge.num`` and ``db->lag.id`` or may
878 drivers even if they do not support FDB isolation. However, ``db->bridge.num``
879 and ``db->lag.id`` are always set to 0 in that case (to denote the lack of
883 separate address databases for each standalone user port. Since FDB entries in
885 for incorrect forwarding decisions. In this case, all standalone ports may
886 share the same database, but the reference counting of host-filtered addresses
887 (not deleting the FDB entry for a port's MAC address if it's still in use by
889 that the port databases are in fact shared. This can be achieved by calling
891 The down side is that the RX filtering lists of each user port are in fact
893 shouldn't have, only because that MAC address was in the RX filtering list of
894 user port B. These packets will still be dropped in software, however.
897 ------------
900 below. They may be absent, return -EOPNOTSUPP, or ``ds->max_num_bridges`` may
901 be non-zero and exceeded, and in this case, joining a bridge port is still
902 possible, but the packet forwarding will take place in software, and the ports
903 under a software bridge must remain configured in the same way as for
910 learning FDB entries in accordance with the software bridge port's state, and
914 have already been autonomously forwarded in the forwarding domain of the
916 switch ports part of the same tree ID to be part of the same bridge forwarding
922 bridge device's transmit function to potentially multiple egress ports (and
923 thereby avoid its cloning in software).
926 packets and have ``skb->offload_fwd_mark`` set to true in the tag protocol
930 handled in hardware and the bridge driver will transmit a single skb for each
936 VLAN-unaware, and in this case the FID must be equal to the FID used by the
937 driver for its VLAN-unaware address database associated with that bridge.
938 Alternatively, the bridge may be VLAN-aware, and in that case, it is guaranteed
939 that the packet is also VLAN-tagged with the VLAN ID that the bridge processed
940 this packet in. It is the responsibility of the hardware to untag the VID on
941 the egress-untagged ports, or keep the tag on the egress-tagged ones.
943 - ``port_bridge_join``: bridge layer function invoked when a given switch port is
950 - ``port_bridge_leave``: bridge layer function invoked when a given switch port is
955 - ``port_stp_state_set``: bridge layer function invoked when a given switch port STP
959 - ``port_bridge_flags``: bridge layer function invoked when a port must
962 standalone ports with address learning disabled and egress flooding of all
968 lack of an explicit address filtering mechanism in the DSA core.
970 - ``port_fast_age``: bridge layer function invoked when flushing the
977 ---------------------
979 - ``port_vlan_filtering``: bridge layer function invoked when the bridge gets
989 - ``port_vlan_add``: bridge layer function invoked when a VLAN is configured
992 forwarding needs to take place in software), or the VLAN is installed to the
994 (``bridge vlan add dev br0 vid 100 self``). VLANs on shared ports are
998 - ``port_vlan_del``: bridge layer function invoked when a VLAN is removed from the
1001 - ``port_fdb_add``: bridge layer function invoked when the bridge wants to install a
1003 specified address in the specified VLAN Id in the forwarding database
1006 - ``port_fdb_del``: bridge layer function invoked when the bridge wants to remove a
1011 - ``port_fdb_dump``: bridge bypass function invoked by ``ndo_fdb_dump`` on the
1012 physical DSA port interfaces. Since DSA does not attempt to keep in sync its
1014 a means to view the entries visible on user ports in the hardware database.
1015 The entries reported by this function have the ``self`` flag in the output of
1018 - ``port_mdb_add``: bridge layer function invoked when the bridge wants to install
1020 specified address in the specified VLAN ID in the forwarding database
1023 - ``port_mdb_del``: bridge layer function invoked when the bridge wants to remove a
1029 ----------------
1031 Link aggregation is implemented in the Linux networking stack by the bonding
1034 supports the feature, and supports bridging between physical ports and LAGs,
1036 ports constitutes a logical port, although DSA has no explicit concept of a
1038 bridge are treated as if all individual physical ports that are members of that
1046 - ``port_lag_join``: function invoked when a given switch port is added to a
1047 LAG. The driver may return ``-EOPNOTSUPP``, and in this case, DSA will fall
1050 - ``port_lag_leave``: function invoked when a given switch port leaves a LAG
1052 - ``port_lag_change``: function invoked when the link state of any member of
1054 of the subset of physical LAG member ports that are up.
1057 can optionally populate ``ds->num_lag_ids`` from the ``dsa_switch_ops::setup``
1061 IEC 62439-2 (MRP)
1062 -----------------
1069 Depending on the node's role in the ring (MRM: Media Redundancy Manager,
1076 however in the case of a device with an offloaded data path such as DSA, it is
1077 necessary for the hardware, even if it is not MRP-aware, to be able to extract
1079 implementation. DSA today has no driver which is MRP-aware, therefore it only
1083 - ``port_mrp_add`` and ``port_mrp_del``: notifies driver when an MRP instance
1086 - ``port_mrp_add_ring_role`` and ``port_mrp_del_ring_role``: function invoked
1091 IEC 62439-3 (HSR/PRP)
1092 ---------------------
1096 networks (which are unaware of the PRP tail tags carried in the packets), and
1097 eliminating the duplicates at the receiver. The High-availability Seamless
1098 Redundancy (HSR) protocol is similar in concept, except all nodes that carry
1099 the redundant traffic are aware of the fact that it is HSR-tagged (because HSR
1100 uses a header with an EtherType of 0x892f) and are physically connected in a
1104 In Linux, both HSR and PRP are implemented in the hsr driver, which
1105 instantiates a virtual, stackable network interface with two member ports.
1113 ``Documentation/networking/netdev-features.rst``. Additionally, the following
1116 - ``port_hsr_join``: function invoked when a given switch port is added to a
1117 DANP/DANH. The driver may return ``-EOPNOTSUPP`` and in this case, DSA will
1120 - ``port_hsr_leave``: function invoked when a given switch port leaves a
1127 -------------------------------------------------------------