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linux-next/Documentation/networking/i40e.txt
Jacob Keller 55877012d5 i40e: document drivers use of ntuple filters 
Add documentation describing the drivers use of ethtool ntuple filters,
including the limitations that it has due to hardware, as well as how it
reads and parses the user-def data block.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
2017-03-23 21:13:33 -07:00

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Linux Base Driver for the Intel(R) Ethernet Controller XL710 Family
===================================================================
Intel i40e Linux driver.
Copyright(c) 2013 Intel Corporation.
Contents
========
- Identifying Your Adapter
- Additional Configurations
- Performance Tuning
- Known Issues
- Support
Identifying Your Adapter
========================
The driver in this release is compatible with the Intel Ethernet
Controller XL710 Family.
For more information on how to identify your adapter, go to the Adapter &
Driver ID Guide at:
http://support.intel.com/support/network/sb/CS-012904.htm
Enabling the driver
===================
The driver is enabled via the standard kernel configuration system,
using the make command:
Make oldconfig/silentoldconfig/menuconfig/etc.
The driver is located in the menu structure at:
-> Device Drivers
-> Network device support (NETDEVICES [=y])
-> Ethernet driver support
-> Intel devices
-> Intel(R) Ethernet Controller XL710 Family
Additional Configurations
=========================
Generic Receive Offload (GRO)
-----------------------------
The driver supports the in-kernel software implementation of GRO. GRO has
shown that by coalescing Rx traffic into larger chunks of data, CPU
utilization can be significantly reduced when under large Rx load. GRO is
an evolution of the previously-used LRO interface. GRO is able to coalesce
other protocols besides TCP. It's also safe to use with configurations that
are problematic for LRO, namely bridging and iSCSI.
Ethtool
-------
The driver utilizes the ethtool interface for driver configuration and
diagnostics, as well as displaying statistical information. The latest
ethtool version is required for this functionality.
The latest release of ethtool can be found from
https://www.kernel.org/pub/software/network/ethtool
Flow Director n-ntuple traffic filters (FDir)
---------------------------------------------
The driver utilizes the ethtool interface for configuring ntuple filters,
via "ethtool -N <device> <filter>".
The sctp4, ip4, udp4, and tcp4 flow types are supported with the standard
fields including src-ip, dst-ip, src-port and dst-port. The driver only
supports fully enabling or fully masking the fields, so use of the mask
fields for partial matches is not supported.
Additionally, the driver supports using the action to specify filters for a
Virtual Function. You can specify the action as a 64bit value, where the
lower 32 bits represents the queue number, while the next 8 bits represent
which VF. Note that 0 is the PF, so the VF identifier is offset by 1. For
example:
... action 0x800000002 ...
Would indicate to direct traffic for Virtual Function 7 (8 minus 1) on queue
2 of that VF.
The driver also supports using the user-defined field to specify 2 bytes of
arbitrary data to match within the packet payload in addition to the regular
fields. The data is specified in the lower 32bits of the user-def field in
the following way:
+----------------------------+---------------------------+
| 31 28 24 20 16 | 15 12 8 4 0|
+----------------------------+---------------------------+
| offset into packet payload | 2 bytes of flexible data |
+----------------------------+---------------------------+
As an example,
... user-def 0x4FFFF ....
means to match the value 0xFFFF 4 bytes into the packet payload. Note that
the offset is based on the beginning of the payload, and not the beginning
of the packet. Thus
flow-type tcp4 ... user-def 0x8BEAF ....
would match TCP/IPv4 packets which have the value 0xBEAF 8bytes into the
TCP/IPv4 payload.
For ICMP, the hardware parses the ICMP header as 4 bytes of header and 4
bytes of payload, so if you want to match an ICMP frames payload you may need
to add 4 to the offset in order to match the data.
Furthermore, the offset can only be up to a value of 64, as the hardware
will only read up to 64 bytes of data from the payload. It must also be even
as the flexible data is 2 bytes long and must be aligned to byte 0 of the
packet payload.
When programming filters, the hardware is limited to using a single input
set for each flow type. This means that it is an error to program two
different filters with the same type that don't match on the same fields.
Thus the second of the following two commands will fail:
ethtool -N <device> flow-type tcp4 src-ip 192.168.0.7 action 5
ethtool -N <device> flow-type tcp4 dst-ip 192.168.15.18 action 1
This is because the first filter will be accepted and reprogram the input
set for TCPv4 filters, but the second filter will be unable to reprogram the
input set until all the conflicting TCPv4 filters are first removed.
Note that the user-defined flexible offset is also considered part of the
input set and cannot be programmed separately for multiple filters of the
same type. However, the flexible data is not part of the input set and
multiple filters may use the same offset but match against different data.
Data Center Bridging (DCB)
--------------------------
DCB configuration is not currently supported.
FCoE
----
The driver supports Fiber Channel over Ethernet (FCoE) and Data Center
Bridging (DCB) functionality. Configuring DCB and FCoE is outside the scope
of this driver doc. Refer to http://www.open-fcoe.org/ for FCoE project
information and http://www.open-lldp.org/ or email list
e1000-eedc@lists.sourceforge.net for DCB information.
MAC and VLAN anti-spoofing feature
----------------------------------
When a malicious driver attempts to send a spoofed packet, it is dropped by
the hardware and not transmitted. An interrupt is sent to the PF driver
notifying it of the spoof attempt.
When a spoofed packet is detected the PF driver will send the following
message to the system log (displayed by the "dmesg" command):
Spoof event(s) detected on VF (n)
Where n=the VF that attempted to do the spoofing.
Performance Tuning
==================
An excellent article on performance tuning can be found at:
http://www.redhat.com/promo/summit/2008/downloads/pdf/Thursday/Mark_Wagner.pdf
Known Issues
============
Support
=======
For general information, go to the Intel support website at:
http://support.intel.com
or the Intel Wired Networking project hosted by Sourceforge at:
http://e1000.sourceforge.net
If an issue is identified with the released source code on the supported
kernel with a supported adapter, email the specific information related
to the issue to e1000-devel@lists.sourceforge.net and copy
netdev@vger.kernel.org.
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