what - netdevconf.org · slide users of dsa 2 design goals and radigms a p ... review) micro chip...

What is DSA?

Design Goals and Paradigms

The Future

Distributed Swit h Ar hite ture

A.K.A. DSA

Andrew Lunn

1

Vivien Didelot

2

Florian Fainelli

3

1

andrew�lunn. h

2

vivien.didelot�savoirfairelinux. om

3

f.fainelli�gmail. om

Netdev 2.1, 2017

Andrew Lunn, Vivien Didelot, Florian Fainelli DSA

What is DSA?


The Future

Outline

1

What is DSA?

DSA in one Slide

Users of DSA

2


History

Design Goals

Paradigms

The D in DSA

3

The Future


What is DSA?


The Future

DSA in one Slide

Users of DSA

1

What is DSA?

DSA in one Slide

Users of DSA

2


History

Design Goals

Paradigms

The D in DSA

3

The Future


What is DSA?


The Future

DSA in one Slide

Users of DSA

DSA in one Slide

Ethernet switch

Ethernet controller

Port 0

Port 1

Port 2

Port 8

Port 3

Port 4

Port 5

I2C controller

MDIO controller

SPI controller

RJ45

RJ45

RJ45

FiberRJ45

RGMII

CPU

DRAM

RGMII RJ45

RJ45

Data path

Control path


What is DSA?


The Future

DSA in one Slide

Users of DSA

The D in DSA

Switch 2

Switch 1

Switch 0

Ethernet MAC

CPU

MDIO controller

cpu

dsa

dsa dsa

eth0

sw0p1

dsa

sw0p1

sw0p2

sw0p3

sw0p4 sw0p5

sw1p0

sw1p1 sw1p2

sw2p0

sw2p1

sw2p0

sw2p2 sw2p3 sw2p4

Marvell tagged frames

User frames (normal, 802.1q)

Control interface (MDIO, SPI, I2C..)


What is DSA?


The Future

DSA in one Slide

Users of DSA

Wi-Fi A ess Point, Set-top Boxes


What is DSA?


The Future

DSA in one Slide

Users of DSA

Industrial Swit hes/Routers, mostly Transport Industry


What is DSA?


The Future

DSA in one Slide

Users of DSA

Supported Swit hes

Marvell 88E6xxx

Broad om B53 (Roboswit h) and Star Fighter 2

Qual omm QCA8K

Mediatek MT7530 (under review)

Mi ro hip LAN9303 (under review)

WIP driver for Mi ro hip KSZ, not yet ontributed


What is DSA?


The Future

History

Design Goals

Paradigms

The D in DSA

1

What is DSA?

DSA in one Slide

Users of DSA

2


History

Design Goals

Paradigms

The D in DSA

3

The Future


What is DSA?


The Future

History

Design Goals

Paradigms

The D in DSA

Added to the kernel in 2008

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Year, Month

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What is DSA?


The Future

History

Design Goals

Paradigms

The D in DSA

History

2008

First ommit, support for some Marvell SOHO swit hes

2014

Broad om SF2, EEPROM, Temperature sensor, EEE, WoL, better PHYLIB

integration, 88E6352

2015

Devi e tree, Hardware bridging, VLANs, Fixup module unload/load, Swit h reset

via GPIO, net onsole

2016

New devi e tree binding, Swit hes as Linux devi es, SPI, MMIO, Broad om B53,

Qual omm QCA8K, 88E6240

2017

88E6390, Se ond generation Star�ghter 2 (BCM7278), TC o�oads, port mirroring


What is DSA?


The Future

History

Design Goals

Paradigms

The D in DSA

Alternative approa hes

OpenWrt/LEDE's sw on�g:

Generi netlink based on�guration

Does not make use of swit h tags, uses VLAN tags for tra� segregation

No per-port network interfa es

Ea h swit h driver is allowed to extend the ontrol API: no onsisten y a ross

devi e drivers

Proposed as a solution in O tober 2013: https://lwn.net/Arti les/571390/

Dis ussion starting point that led to swit hdev!


https://lwn.net/Articles/571390/

What is DSA?


The Future

History

Design Goals

Paradigms

The D in DSA

Other approa hes

Other approa hes:

Qui k-n-dirty /pro , /sys/, debugfs, io tl() interfa es from various SoC vendors

Vendor spe i� and proprietary swit h SDK in user spa e

Have the bootloader on�gure the swit h!


What is DSA?


The Future

History

Design Goals

Paradigms

The D in DSA

The Swit h as a Hardware A elerator

During various onferen e orridor side dis ussions around 2014 it was de ided how to

model Swit hes

Swit h ports are Linux network interfa es

Standard Linux tools used to on�gure interfa es, ip(8), if on�g(8)

Linux bridge on ept used for bridging interfa es, ip(8), bridge(8), brt tl(8)

Linux team/bonding on ept for port trunks,

The swit h just a elerates what Linux an already do

DSA has been doing this sin e 2008!


What is DSA?


The Future

History

Design Goals

Paradigms

The D in DSA

The Data Plane

DSA provides the data plane

Linux slave Interfa e for ea h port

Tagging proto ols, to dire t frames from the SoC to a spe i� port

Taggers for Marvell DSA & EDSA, Broad om and Qual om, plus generi trailer

TX: Slave interfa e -> tagger -> master interfa e -> Swit h

RX: master interfa e netif_re eive_skb() -> tag parser, slave interfa e sele tion

-> netif_re eive_skb


What is DSA?


The Future

History

Design Goals

Paradigms

The D in DSA

Ethernet frame pro essing

M�� M�� Ether type Payload FCS

MAC DA MAC SA Ether type Payload FCSSwitch tag

Source portMetadataEgress type

Destination portsMetadataIngress type

Normal Ethernet frame

Ingress tagged (CPU towards switch) frame

MAC DA MAC SA Ether type Payload FCSSwitch tag

Egress tagged (switch towards CPU) frame


What is DSA?


The Future

History

Design Goals

Paradigms

The D in DSA

Network sta k �ow

Network driverRX path

skb�dev = eth0

netif_receive_skb()

eth_type_trans()

netdev_uses_dsa()?

ip_rcv()

XX_tag_rcv()

Switch port valid?

skb�dev = sw0p0

Driver/HW layer Layer agnostic

Ethernet layer

Layer 3

DSA tag layer

Discard

Yes

Yes

No

No


What is DSA?


The Future

History

Design Goals

Paradigms

The D in DSA

The Control Plane

About SWITCHDEV:

Stateless framework in the kernel under net/swit hdev/

Provides the ontrol knobs within the networking sta k to push o�oads towards

spe ialized devi es (swit hdev_ops)

Provides an abstra t model of obje ts (VLANs, FDBs, MDBs,) to be pushed to

these devi es (swit hdev_obj)

Is not a devi e driver model: no stri t de�nition of what a swit h devi e is

Only operates at the network devi e (net_devi e) layer


What is DSA?


The Future

History

Design Goals

Paradigms

The D in DSA

The Control Plane

DSA vs. SWITCHDEV:

Stateful framework under net/dsa/

Colle tion of vendor-spe i� swit h tags: Marvell, Broad om, Qual omm, Mediatek

Provides an abstra ted model of a swit h: dsa_swit h and a olle tion of

swit hes: dsa_swit h_tree

Binds network devi es (netdev_ops), ethtool (ethtool_ops) and swit h drivers

together

Well de�ned devi e (Devi e Tree) and driver model (dsa_swit h_ops)

Implements swit hdev_ops for supported o�oads: bridge, VLAN, FDB, MDB


What is DSA?


The Future

History

Design Goals

Paradigms

The D in DSA

Cross- hip on�guration

Switch 2Switch 1Switch 0

CPU

sw0p0 sw0p1 sw0p2 sw1p0 sw1p1 sw1p2 sw2p1sw2p0 sw2p2

Marvell tagged frames

Bridge membership

Bridge br0

sw2p3sw2p4sw1p3sw1p4sw0p3sw0p4


What is DSA?


The Future

History

Design Goals

Paradigms

The D in DSA


Current behavior:

Inter onne ted swit h hips reate a swit h fabri

DSA drivers manage single hip (stru t dsa_swit h)

DSA links on�gured to pass frames to any port

Problem?

br0 bridging? Swit hes an potentially leak ross- hip frames!

br0 VLAN 42? Swit h 1 won't pass tra� !


What is DSA?


The Future

History

Design Goals

Paradigms

The D in DSA


Solutions?

Cross- hip bridging (DONE):

DSA ore noti�es drivers about fabri bridge events ( ross hip_bridge_{join,leave}

ops)

mv88e6xxx on�gure Cross- hip Port Based VLAN Table (PVT, Marvell spe i� )

Cross- hip VLAN (WIP):

DSA ore noti�es drivers about swit hdev port obje ts (VLAN, FDB, MDB) so that

drivers allow tra� to pass


What is DSA?


The Future

1

What is DSA?

DSA in one Slide

Users of DSA

2


History

Design Goals

Paradigms

The D in DSA

3

The Future


What is DSA?


The Future

Hopefully oming soon

Multiple CPU ports

Often seen in Wi-Fi devi es to double SoC <-> Swit h Bandwidth

Often one CPU port stati ally mapped to �WAN� port

Depends on hipset features, we an do better, load balan ing

IGMP snooping on bridges

Better distributed swit h support for Marvell devi es

Better support for Fiber interfa es

Mediatek driver merged

Mi ro hip drivers merged


What is DSA?


The Future

Maybe Later???

Team/bonding?

TCAM support for o�oading part of the �rewall?

Qual omm Hardware NAT?

More Vendor supported development?

Metering, broad ast storm suppression, QoS (priorities, maps) o�oads again


What is DSA?


The Future

Questions

Questions???


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