Documentation: net: dsa: Describe DSA switch configuration

Document DSA tagged and VLAN based switch configuration by showcases.
Signed-off-by: NBenedikt Spranger <b.spranger@linutronix.de>
Reviewed-by: NAndrew Lunn <andrew@lunn.ch>
Reviewed-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Documentation/networking/dsa/configuration.rst

+.. SPDX-License-Identifier: GPL-2.0
+
+=======================================
+DSA switch configuration from userspace
+=======================================
+
+The DSA switch configuration is not integrated into the main userspace
+network configuration suites by now and has to be performed manualy.
+
+.. _dsa-config-showcases:
+
+Configuration showcases
+-----------------------
+
+To configure a DSA switch a couple of commands need to be executed. In this
+documentation some common configuration scenarios are handled as showcases:
+
+*single port*
+  Every switch port acts as a different configurable Ethernet port
+
+*bridge*
+  Every switch port is part of one configurable Ethernet bridge
+
+*gateway*
+  Every switch port except one upstream port is part of a configurable
+  Ethernet bridge.
+  The upstream port acts as different configurable Ethernet port.
+
+All configurations are performed with tools from iproute2, which is available
+at https://www.kernel.org/pub/linux/utils/net/iproute2/
+
+Through DSA every port of a switch is handled like a normal linux Ethernet
+interface. The CPU port is the switch port connected to an Ethernet MAC chip.
+The corresponding linux Ethernet interface is called the master interface.
+All other corresponding linux interfaces are called slave interfaces.
+
+The slave interfaces depend on the master interface. They can only brought up,
+when the master interface is up.
+
+In this documentation the following Ethernet interfaces are used:
+
+*eth0*
+  the master interface
+
+*lan1*
+  a slave interface
+
+*lan2*
+  another slave interface
+
+*lan3*
+  a third slave interface
+
+*wan*
+  A slave interface dedicated for upstream traffic
+
+Further Ethernet interfaces can be configured similar.
+The configured IPs and networks are:
+
+*single port*
+  * lan1: 192.0.2.1/30 (192.0.2.0 - 192.0.2.3)
+  * lan2: 192.0.2.5/30 (192.0.2.4 - 192.0.2.7)
+  * lan3: 192.0.2.9/30 (192.0.2.8 - 192.0.2.11)
+
+*bridge*
+  * br0: 192.0.2.129/25 (192.0.2.128 - 192.0.2.255)
+
+*gateway*
+  * br0: 192.0.2.129/25 (192.0.2.128 - 192.0.2.255)
+  * wan: 192.0.2.1/30 (192.0.2.0 - 192.0.2.3)
+
+.. _dsa-tagged-configuration:
+
+Configuration with tagging support
+----------------------------------
+
+The tagging based configuration is desired and supported by the majority of
+DSA switches. These switches are capable to tag incoming and outgoing traffic
+without using a VLAN based configuration.
+
+single port
+~~~~~~~~~~~
+
+.. code-block:: sh
+
+  # configure each interface
+  ip addr add 192.0.2.1/30 dev lan1
+  ip addr add 192.0.2.5/30 dev lan2
+  ip addr add 192.0.2.9/30 dev lan3
+
+  # The master interface needs to be brought up before the slave ports.
+  ip link set eth0 up
+
+  # bring up the slave interfaces
+  ip link set lan1 up
+  ip link set lan2 up
+  ip link set lan3 up
+
+bridge
+~~~~~~
+
+.. code-block:: sh
+
+  # The master interface needs to be brought up before the slave ports.
+  ip link set eth0 up
+
+  # bring up the slave interfaces
+  ip link set lan1 up
+  ip link set lan2 up
+  ip link set lan3 up
+
+  # create bridge
+  ip link add name br0 type bridge
+
+  # add ports to bridge
+  ip link set dev lan1 master br0
+  ip link set dev lan2 master br0
+  ip link set dev lan3 master br0
+
+  # configure the bridge
+  ip addr add 192.0.2.129/25 dev br0
+
+  # bring up the bridge
+  ip link set dev br0 up
+
+gateway
+~~~~~~~
+
+.. code-block:: sh
+
+  # The master interface needs to be brought up before the slave ports.
+  ip link set eth0 up
+
+  # bring up the slave interfaces
+  ip link set wan up
+  ip link set lan1 up
+  ip link set lan2 up
+
+  # configure the upstream port
+  ip addr add 192.0.2.1/30 dev wan
+
+  # create bridge
+  ip link add name br0 type bridge
+
+  # add ports to bridge
+  ip link set dev lan1 master br0
+  ip link set dev lan2 master br0
+
+  # configure the bridge
+  ip addr add 192.0.2.129/25 dev br0
+
+  # bring up the bridge
+  ip link set dev br0 up
+
+.. _dsa-vlan-configuration:
+
+Configuration without tagging support
+-------------------------------------
+
+A minority of switches are not capable to use a taging protocol
+(DSA_TAG_PROTO_NONE). These switches can be configured by a VLAN based
+configuration.
+
+single port
+~~~~~~~~~~~
+The configuration can only be set up via VLAN tagging and bridge setup.
+
+.. code-block:: sh
+
+  # tag traffic on CPU port
+  ip link add link eth0 name eth0.1 type vlan id 1
+  ip link add link eth0 name eth0.2 type vlan id 2
+  ip link add link eth0 name eth0.3 type vlan id 3
+
+  # The master interface needs to be brought up before the slave ports.
+  ip link set eth0 up
+  ip link set eth0.1 up
+  ip link set eth0.2 up
+  ip link set eth0.3 up
+
+  # bring up the slave interfaces
+  ip link set lan1 up
+  ip link set lan1 up
+  ip link set lan3 up
+
+  # create bridge
+  ip link add name br0 type bridge
+
+  # activate VLAN filtering
+  ip link set dev br0 type bridge vlan_filtering 1
+
+  # add ports to bridges
+  ip link set dev lan1 master br0
+  ip link set dev lan2 master br0
+  ip link set dev lan3 master br0
+
+  # tag traffic on ports
+  bridge vlan add dev lan1 vid 1 pvid untagged
+  bridge vlan add dev lan2 vid 2 pvid untagged
+  bridge vlan add dev lan3 vid 3 pvid untagged
+
+  # configure the VLANs
+  ip addr add 192.0.2.1/30 dev eth0.1
+  ip addr add 192.0.2.5/30 dev eth0.2
+  ip addr add 192.0.2.9/30 dev eth0.3
+
+  # bring up the bridge devices
+  ip link set br0 up
+
+
+bridge
+~~~~~~
+
+.. code-block:: sh
+
+  # tag traffic on CPU port
+  ip link add link eth0 name eth0.1 type vlan id 1
+
+  # The master interface needs to be brought up before the slave ports.
+  ip link set eth0 up
+  ip link set eth0.1 up
+
+  # bring up the slave interfaces
+  ip link set lan1 up
+  ip link set lan2 up
+  ip link set lan3 up
+
+  # create bridge
+  ip link add name br0 type bridge
+
+  # activate VLAN filtering
+  ip link set dev br0 type bridge vlan_filtering 1
+
+  # add ports to bridge
+  ip link set dev lan1 master br0
+  ip link set dev lan2 master br0
+  ip link set dev lan3 master br0
+  ip link set eth0.1 master br0
+
+  # tag traffic on ports
+  bridge vlan add dev lan1 vid 1 pvid untagged
+  bridge vlan add dev lan2 vid 1 pvid untagged
+  bridge vlan add dev lan3 vid 1 pvid untagged
+
+  # configure the bridge
+  ip addr add 192.0.2.129/25 dev br0
+
+  # bring up the bridge
+  ip link set dev br0 up
+
+gateway
+~~~~~~~
+
+.. code-block:: sh
+
+  # tag traffic on CPU port
+  ip link add link eth0 name eth0.1 type vlan id 1
+  ip link add link eth0 name eth0.2 type vlan id 2
+
+  # The master interface needs to be brought up before the slave ports.
+  ip link set eth0 up
+  ip link set eth0.1 up
+  ip link set eth0.2 up
+
+  # bring up the slave interfaces
+  ip link set wan up
+  ip link set lan1 up
+  ip link set lan2 up
+
+  # create bridge
+  ip link add name br0 type bridge
+
+  # activate VLAN filtering
+  ip link set dev br0 type bridge vlan_filtering 1
+
+  # add ports to bridges
+  ip link set dev wan master br0
+  ip link set eth0.1 master br0
+  ip link set dev lan1 master br0
+  ip link set dev lan2 master br0
+
+  # tag traffic on ports
+  bridge vlan add dev lan1 vid 1 pvid untagged
+  bridge vlan add dev lan2 vid 1 pvid untagged
+  bridge vlan add dev wan vid 2 pvid untagged
+
+  # configure the VLANs
+  ip addr add 192.0.2.1/30 dev eth0.2
+  ip addr add 192.0.2.129/25 dev br0
+
+  # bring up the bridge devices
+  ip link set br0 up

Documentation/networking/dsa/index.rst

@@ -9,3 +9,4 @@ Distributed Switch Architecture
    bcm_sf2
    lan9303
    sja1105
+   configuration