When a packet enters kernel datapath and there is no flow to handle it,
packet goes to userspace through a MISS upcall. With per-CPU upcall
dispatch mechanism, we're using the current CPU id to select the
Netlink PID on which to send this packet. This allows us to send
packets from the same traffic flow through the same handler.
The handler will process the packet, install required flow into the
kernel and re-inject the original packet via OVS_PACKET_CMD_EXECUTE.
While handling OVS_PACKET_CMD_EXECUTE, however, we may hit a
recirculation action that will pass the (likely modified) packet
through the flow lookup again. And if the flow is not found, the
packet will be sent to userspace again through another MISS upcall.
However, the handler thread in userspace is likely running on a
different CPU core, and the OVS_PACKET_CMD_EXECUTE request is handled
in the syscall context of that thread. So, when the time comes to
send the packet through another upcall, the per-CPU dispatch will
choose a different Netlink PID, and this packet will end up processed
by a different handler thread on a different CPU.
The process continues as long as there are new recirculations, each
time the packet goes to a different handler thread before it is sent
out of the OVS datapath to the destination port. In real setups the
number of recirculations can go up to 4 or 5, sometimes more.
There is always a chance to re-order packets while processing upcalls,
because userspace will first install the flow and then re-inject the
original packet. So, there is a race window when the flow is already
installed and the second packet can match it inside the kernel and be
forwarded to the destination before the first packet is re-injected.
But the fact that packets are going through multiple upcalls handled
by different userspace threads makes the reordering noticeably more
likely, because we not only have a race between the kernel and a
userspace handler (which is hard to avoid), but also between multiple
userspace handlers.
For example, let's assume that 10 packets got enqueued through a MISS
upcall for handler-1, it will start processing them, will install the
flow into the kernel and start re-injecting packets back, from where
they will go through another MISS to handler-2. Handler-2 will install
the flow into the kernel and start re-injecting the packets, while
handler-1 continues to re-inject the last of the 10 packets, they will
hit the flow installed by handler-2 and be forwarded without going to
the handler-2, while handler-2 still re-injects the first of these 10
packets. Given multiple recirculations and misses, these 10 packets
may end up completely mixed up on the output from the datapath.
Let's provide the original upcall PID via the new netlink attribute
OVS_PACKET_ATTR_UPCALL_PID. This way the upcall triggered during the
execution will go to the same handler. Packets will be enqueued to
the same socket and re-injected in the same order. This doesn't
eliminate re-ordering as stated above, since we still have a race
between the kernel and the handler thread, but it allows to eliminate
races between multiple handlers.
The openvswitch kernel module ignores unknown attributes for the
OVS_PACKET_CMD_EXECUTE, so it's safe to provide it even on older
kernels.
Reported-at: https://issues.redhat.com/browse/FDP-1479
Link: https://lore.kernel.org/netdev/20250702155043.2331772-1-i.maximets@ovn.org/
Acked-by: Eelco Chaudron <echaudro@redhat.com>
Acked-by: Flavio Leitner <fbl@sysclose.org>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
Upon tunnel output failure, due to routing failure for example, add an
explicit drop action, so it will appear in the dp-flows for better
visibility for that case.
For those, add additional drop reasons.
Reviewed-by: Roi Dayan <roid@nvidia.com>
Signed-off-by: Eli Britstein <elibr@nvidia.com>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
STT and LISP tunnel types were deprecated and marked for removal in
the following commits in the OVS 3.5 release:
3b37a6154a59 ("netdev-vport: Deprecate STT tunnel port type.")
8d7ac031c03d ("netdev-vport: Deprecate LISP tunnel port type.")
Main reasons were that STT was rejected in upstream kernel and the
LISP was never upstreamed as well and doesn't really have a supported
implementation. Both protocols also appear to have lost their former
relevance.
Removing both now. While at it, also fixing some small documentation
issues and comments.
Acked-by: Eelco Chaudron <echaudro@redhat.com>
Acked-by: Alin Serdean <aserdean@ovn.org>
Acked-by: Kevin Traynor <ktraynor@redhat.com>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
STT tunnel implementation was rejected in the upstream Linux kernel
long time ago and will probably never be there. So, the only
implementation for Linux is in the OOT kernel module shipped with
OVS 2.17. It is deprecated and will reach end of life in Feb 2025.
In addition, modern network interface cards support various hardware
offload features with UDP tunnels, diminishing the main selling point
of STT - the ability to reuse hardware offload features meant for TCP.
Deprecate the port type now, so it can be removed once 2.17 is EoL.
There is another implementation for this tunnel type in the Windows
datapath. However, the protocol itself is considered harmful as it
may confuse stateful network hardware by pretending to be TCP (hence
the reason it was rejected in the Linux kernel). So, it is better if
we deprecate this implementation and stop supporting it as well.
The standard draft for the protocol itself is also expired and
archived with the latest update made in 2016:
https://datatracker.ietf.org/doc/draft-davie-stt/
Acked-by: Eelco Chaudron <echaudro@redhat.com>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
Tunnel support is in upstream Linux kernel since 2013. However,
despite the FAQ saying so, I'm not aware of actual attempts to bring
support for LISP tunnels upstream. The only available implementation
is in OOT kernel module shipped with OVS 2.17. It is deprecated and
will reach EoL in Feb 2025.
Mark the tunnel port type as deprecated, so we can fully remove the
support once the only available implementation reaches end of life
together with OVS 2.17.
Acked-by: Eelco Chaudron <echaudro@redhat.com>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
Add support for parsing and formatting the new action.
Also, flag OVS_ACTION_ATTR_SAMPLE as requiring datapath assistance if it
contains a nested OVS_ACTION_ATTR_PSAMPLE. The reason is that the
sampling rate from the parent "sample" is made available to the nested
"psample" by the kernel.
Acked-by: Eelco Chaudron <echaudro@redhat.com>
Signed-off-by: Adrian Moreno <amorenoz@redhat.com>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
Kernel support has been added for this action. As such, we need to probe
the datapath for support.
Acked-by: Eelco Chaudron <echaudro@redhat.com>
Signed-off-by: Eric Garver <eric@garver.life>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
This is prep for adding a different OVS_ACTION_ATTR_ enum value. This
action, OVS_ACTION_ATTR_DEC_TTL, is not actually implemented. However,
to make -Werror happy we must add a case to all existing switches.
Acked-by: Eelco Chaudron <echaudro@redhat.com>
Signed-off-by: Eric Garver <eric@garver.life>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
SRv6 (Segment Routing IPv6) tunnel vport is responsible
for encapsulation and decapsulation the inner packets with
IPv6 header and an extended header called SRH
(Segment Routing Header). See spec in:
https://datatracker.ietf.org/doc/html/rfc8754
This patch implements SRv6 tunneling in userspace datapath.
It uses `remote_ip` and `local_ip` options as with existing
tunnel protocols. It also adds a dedicated `srv6_segs` option
to define a sequence of routers called segment list.
Signed-off-by: Nobuhiro MIKI <nmiki@yahoo-corp.jp>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
Add support to count upcall packets per port, both succeed and failed,
which is a better way to see how many packets upcalled on each interface.
Acked-by: Eelco Chaudron <echaudro@redhat.com>
Signed-off-by: wangchuanlei <wangchuanlei@inspur.com>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
Update the necessary make and configure files to remove the Linux
datapath and then remove the datapath.
Move datapath/linux/compat/include/linux/openvswitch.h to
include/linux/openvswitch.h because it is needed to generate header
files used by the userspace switch.
Also remove references to the Linux datapath from auxiliary files
and utilities since it is no longer supported.
Signed-off-by: Greg Rose <gvrose8192@gmail.com>
Reviewed-by: David Marchand <david.marchand@redhat.com>
Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
Until now, the OVS source tree has had a whole maze of header files that
make "#include <linux/openvswitch.h>" work OK regardless of platform, but
this confuses everyone new to the tree, at first glance, and is difficult
to understand at second glance too.
This commit renames include/linux/openvswitch.h to
datapath/linux/compat/include/linux/openvswitch.h without other change,
then modifies the userspace build to generate a header that makes sense in
portable Open vSwitch userspace from that header.
It then removes all the remaining include/linux/* files since they are now
unused.
Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Jesse Gross <jesse@nicira.com>
Keeping the order of netlink attribute definition in the order of
upstreaming is the best way to keep all released user space program
forward compatible with upstreamed kernel modules.
Adjust action netlink attribute order to match with the current
upstreaming plan.
Recirc and hash actions are introduced in branch 2.3, which will be
fixed by the patch. The MPLS actions have been released since
branch-2.1 but there is no kernel implementation of them prior to
branch 2.3. Thus the ordering change should not affect them.
Signed-off-by: Andy Zhou <azhou@nicira.com>
Acked-by: Pravin B Shelar <pshelar@nicira.com>
Allow datapath to recognize and extract MPLS labels into flow keys
and execute actions which push, pop, and set labels on packets.
Based heavily on work by Leo Alterman, Ravi K, Isaku Yamahata and Joe Stringer.
Cc: Ravi K <rkerur@gmail.com>
Cc: Leo Alterman <lalterman@nicira.com>
Cc: Isaku Yamahata <yamahata@valinux.co.jp>
Cc: Joe Stringer <joe@wand.net.nz>
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Jesse Gross <jesse@nicira.com>
This adds support for Geneve - Generic Network Virtualization
Encapsulation. The protocol is documented at
http://tools.ietf.org/html/draft-gross-geneve-00
The kernel implementation is completely agnostic to the options
that are in use and can handle newly defined options without
further work. It does this by simply matching on a byte array
of options and allowing userspace to setup flows on this array.
Userspace currently implements only support for basic version of
Geneve. It can work with the base header (including the VNI) and
is capable of parsing options but does not currently support any
particular option definitions. Over time, the intention is to
allow options to be matched through OpenFlow without requiring
explicit support in OVS userspace.
Signed-off-by: Jesse Gross <jesse@nicira.com>
Acked-by: Thomas Graf <tgraf@suug.ch>
Acked-by: Pravin B Shelar <pshelar@nicira.com>
Some tunnel formats have mechanisms for indicating that packets are
OAM frames that should be handled specially (either as high priority or
not forwarded beyond an endpoint). This provides support for allowing
those types of packets to be matched.
Signed-off-by: Jesse Gross <jesse@nicira.com>
Acked-by: Thomas Graf <tgraf@suug.ch>
Acked-by: Pravin B Shelar <pshelar@nicira.com>
Currently, the flow information that is matched for tunnels and
the tunnel data passed around with packets is the same. However,
as additional information is added this is not necessarily desirable,
as in the case of pointers.
This adds a new structure for tunnel metadata which currently contains
only the existing struct. This change is purely internal to the kernel
since the current OVS_KEY_ATTR_IPV4_TUNNEL is simply a compressed version
of OVS_KEY_ATTR_TUNNEL that is translated at flow setup.
Signed-off-by: Jesse Gross <jesse@nicira.com>
Acked-by: Thomas Graf <tgraf@suug.ch>
Acked-by: Pravin B Shelar <pshelar@nicira.com>
Key attributes relating to actual packet headers are ignored for
OVS_PACKET_CMD_EXECUTE as the header key attributes are retrieved
from the packet itself.
Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com>
Acked-by: Jesse Gross <jesse@nicira.com>
In general, all Netlink 64-bit data may be 4-byte aligned, due to
netlink header and attributes being 4-aligned.
To avoid unaligned access the data should be copied out of the netlink
attribute before access.
Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com>
Acked-by: Jesse Gross <jesse@nicira.com>
Rename hash_bias to hash_basis to make it consistent with similar
usages.
Signed-off-by: Andy Zhou <azhou@nicira.com>
Acked-by: Jesse Gross <jesse@nicira.com>
Currently recirculation action can optionally compute hash. This patch
adds a hash action that is independent of the recirc action, which
no longer computes hash. For megaflow bond with recirc, the output
to a bond port action will look like:
hash(hash_l4(0)), recirc(<recirc_id>)
Obviously, when a recirculation application that does not depend on
hash value can just use the recirc action alone.
Signed-off-by: Andy Zhou <azhou@nicira.com>
Reviewed-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Acked-by: Pravin B Shelar <pshelar@nicira.com
In order to allow handlers directly read upcalls from datapath,
we need to support per-handler netlink socket for each vport in
datapath. This commit makes this happen. Also, it is guaranteed
to be backward compatible with previous branch.
Signed-off-by: Alex Wang <alexw@nicira.com>
Acked-by: Thomas Graf <tgraf@redhat.com>
Acked-by: Pravin B Shelar <pshelar@nicira.com>
Jesse helped to clarify how to maintain the ABI. Making the
adjustment accordingly and add some comments.
Signed-off-by: Andy Zhou <azhou@nicira.com>
Acked-by: Jesse Gross <jesse@nicira.com>
Wrap long lines, fix whitespaces, and fix a typo in a comment.
No functional changes are intended.
Cc: Andy Zhou <azhou@nicira.com>
Signed-off-by: YAMAMOTO Takashi <yamamoto@valinux.co.jp>
Signed-off-by: Andy Zhou <azhou@nicira.com>
Add basic recirculation infrastructure and user space
data path support for it. The following bond mega flow patch will
make use of this infrastructure.
Signed-off-by: Andy Zhou <azhou@nicira.com>
Acked-by: Ben Pfaff <blp@nicira.com>
Flow SET can accept an empty set of actions, with the intended
semantics of leaving existing actions unmodified. This seems to have
been brokin after OVS 1.7, as we have assigned the flow's actions
pointer to NULL in this case, but we never check for the NULL pointer
later on. This patch restores the intended behavior and documents it
in the include/linux/openvswitch.h.
Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com>
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
OpenFlow 1.1 and 1.2 always inserted MPLS labels after VLAN tags.
OpenFlow 1.3 and 1.4 insert MPLS labels before VLAN tags.
OpenFlow 1.3.4 and 1.5, both in preparation, recognize that the change in
1.3 was an error and revert it. This commit implements that reversion
in Open vSwitch.
EXT-457.
Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Simon Horman <horms@verge.net.au>
Drop user features if an outdated user space instance that does not
understand the concept of user_features attempted to create a new
datapath.
Signed-off-by: Thomas Graf <tgraf@suug.ch>
Reviewed-by: Daniel Borkmann <dborkman@redhat.com>
Signed-off-by: Jesse Gross <jesse@nicira.com>
tcp_flags=flags/mask
Bitwise match on TCP flags. The flags and mask are 16-bit num‐
bers written in decimal or in hexadecimal prefixed by 0x. Each
1-bit in mask requires that the corresponding bit in port must
match. Each 0-bit in mask causes the corresponding bit to be
ignored.
TCP protocol currently defines 9 flag bits, and additional 3
bits are reserved (must be transmitted as zero), see RFCs 793,
3168, and 3540. The flag bits are, numbering from the least
significant bit:
0: FIN No more data from sender.
1: SYN Synchronize sequence numbers.
2: RST Reset the connection.
3: PSH Push function.
4: ACK Acknowledgement field significant.
5: URG Urgent pointer field significant.
6: ECE ECN Echo.
7: CWR Congestion Windows Reduced.
8: NS Nonce Sum.
9-11: Reserved.
12-15: Not matchable, must be zero.
Signed-off-by: Jarno Rajahalme <jrajahalme@nicira.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Jesse Gross <jesse@nicira.com>
Collect mega flow mask stats. ovs-dpctl show command can be used to
display them.
Signed-off-by: Andy Zhou <azhou@nicira.com>
Signed-off-by: Jesse Gross <jesse@nicira.com>
This patch adds support for rewriting SCTP src,dst ports similar to the
functionality already available for TCP/UDP.
Rewriting SCTP ports is expensive due to double-recalculation of the
SCTP checksums; this is performed to ensure that packets traversing OVS
with invalid checksums will continue to the destination with any
checksum corruption intact.
Reviewed-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Joe Stringer <joe@wand.net.nz>
Signed-off-by: Ben Pfaff <blp@nicira.com>
Add wildcarded flow support in kernel datapath.
Wildcarded flow can improve OVS flow set up performance by avoid sending
matching new flows to the user space program. The exact performance boost
will largely dependent on wildcarded flow hit rate.
In case all new flows hits wildcard flows, the flow set up rate is
within 5% of that of linux bridge module.
Pravin has made significant contributions to this patch. Including API
clean ups and bug fixes.
Co-authored-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Signed-off-by: Andy Zhou <azhou@nicira.com>
[jesse: Additional documentation, fix memory leak, and improve validation.]
Signed-off-by: Jesse Gross <jesse@nicira.com>
Note that OVS_KEY_ATTR_MPLS may be an array of ovs_key_mpls
and that the acceptable length may be restricted by the implementation.
Currently the user-space datapath and proposed kernel datapath
implementation restrict the length to a single element.
Also update the mpls_top_lse name of the element of struct ovs_key_mpls,
as it is an array of LSEs and thus not necessarily just the top LSE.
As requested by Jesse Gross
Cc: Jesse Gross <jesse@nicira.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Jesse Gross <jesse@nicira.com>
Patch ports have been completely moved to userspace at this point
but one part of the interface remained. It's no longer used by
either userspace or kernel so this deletes it.
Signed-off-by: Jesse Gross <jesse@nicira.com>
Acked-by: Pravin B Shelar <pshelar@nicira.com>
Since userspace flow based tunneling code is checked in, the kernel
port based tunneling code can be removed.
Patch removes following components:
- tunnel ports hash table and moved tunnel ports list to individual
vports.
- Cleaned per tnl-port config.
- OVS_KEY_ATTR_TUN_ID action is removed.
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Acked-by: Jesse Gross <jesse@nicira.com>
Bug #15078
LISP is an experimental layer 3 tunneling protocol, described in RFC
6830. This patch adds support for LISP tunneling. Since LISP
encapsulated packets do not carry an Ethernet header, it is removed
before encapsulation, and added with hardcoded source and destination
MAC addresses after decapsulation. The harcoded MAC chosen for this
purpose is the locally administered address 02:00:00:00:00:00. Flow
actions can be used to rewrite this MAC for correct reception. As such,
this patch is intended to be used for static network configurations, or
with a LISP capable controller.
Signed-off-by: Lorand Jakab <lojakab@cisco.com>
Signed-off-by: Kyle Mestery <kmestery@cisco.com>
Signed-off-by: Jesse Gross <jesse@nicira.com>
The CAPWAP implementation is just the encapsulation format and
therefore really not the full protocol. While there were some
uses of it (primarily hardware support and UDP transport). But
these are most likely better provided by VXLAN.
Following patch removes CAPWAP tunneling support.
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Acked-by: Jesse Gross <jesse@nicira.com>
Until now, the optional OVS_USERSPACE_ATTR_USERDATA attribute had to be
exactly 64 bits long, if it was present. However, 64 bits is not enough
space to associate as much information with a flow as would be convenient
for some userspace features now under development. This commit generalizes
the attribute, allowing it to be any length.
This generalization is backward-compatible: if userspace only uses 64-bit
attributes, then it will not see any change in behavior.
CC: Romain Lenglet <rlenglet@vmware.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Jesse Gross <jesse@nicira.com>
This patch implements use-space datapath and non-datapath code
to match and use the datapath API set out in Leo Alterman's patch
"user-space datapath: Add basic MPLS support to kernel".
The resulting MPLS implementation supports:
* Pushing a single MPLS label
* Poping a single MPLS label
* Modifying an MPLS lable using set-field or load actions
that act on the label value, tc and bos bit.
* There is no support for manipulating the TTL
this is considered future work.
The single-level push pop limitation is implemented by processing
push, pop and set-field/load actions in order and discarding information
that would require multiple levels of push/pop to be supported.
e.g.
push,push -> the first push is discarded
pop,pop -> the first pop is discarded
This patch is based heavily on work by Ravi K.
Cc: Ravi K <rkerur@gmail.com>
Reviewed-by: Isaku Yamahata <yamahata@valinux.co.jp>
Signed-off-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Ben Pfaff <blp@nicira.com>
Now that userspace implements patch ports completely internally,
it's possible to remove the kernel implementation of them.
Signed-off-by: Jesse Gross <jesse@nicira.com>
Acked-by: Kyle Mestery <kmestery@cisco.com>
We want to move the GRE vport ID into the upstream range but in
order to ease the transition kept the old ID around for one release.
This removes the old value.
Signed-off-by: Jesse Gross <jesse@nicira.com>
Acked-by: Kyle Mestery <kmestery@cisco.com>
The ability to retrieve and set MAC addresses on vports is only
necessary for tunnel ports (the addresses for actual devices can be
retrieved through direct Linux mechanisms). Tunnel ports only used
the information for the purpose of generating path MTU discovery
packets, which has now been removed. Current userspace code already
reflects these changes, so this drops the functionality from the
kernel.
Signed-off-by: Jesse Gross <jesse@nicira.com>
Acked-by: Kyle Mestery <kmestery@cisco.com>
Following patch breaks down single ipv4_tunnel netlink attribute into
individual member attributes. It will help when we extend tunneling
parameters in future.
Signed-off-by: Pravin B Shelar <pshelar@nicira.com>
Acked-by: Jesse Gross <jesse@nicira.com>
Bug #14611
ODP ports are now 32-bit, so OVSP_LOCAL should be too.
(Internally, kernel module still keeps port numbers 16-bit, though.)
Signed-off-by: Jarno Rajahalme <jarno.rajahalme@nsn.com>
Signed-off-by: Jesse Gross <jesse@nicira.com>
Add support for VXLAN tunnels to Open vSwitch. Add support
for setting the destination UDP port on a per-port basis.
This is done by adding a "dst_port" parameter to the port
configuration. This is only applicable currently to VXLAN
tunnels.
Please note this currently does not implement any sort of multicast
learning. With this patch, VXLAN tunnels must be configured similar
to GRE tunnels (e.g. point to point). A subsequent patch will implement
a VXLAN control plane in userspace to handle multicast learning.
This patch set is based on one posted by Ben Pfaff on Oct. 12, 2011
to the ovs-dev mailing list:
http://openvswitch.org/pipermail/dev/2011-October/012051.html
The patch has been maintained, updated, and freshened by me and a
version of it is available at the following github repository:
https://github.com/mestery/ovs-vxlan/tree/vxlan
I've tested this patch with multiple VXLAN tunnels between hosts
using different UDP port numbers. Performance is on par (though
slightly faster) than comparable GRE tunnels.
See the following IETF draft for additional information about VXLAN:
http://tools.ietf.org/html/draft-mahalingam-dutt-dcops-vxlan-02
Signed-off-by: Kyle Mestery <kmestery@cisco.com>
[jesse: simplify error path in vxlan_tunnel_setup, don't print default VXLAN port,
and remove dead code]
Signed-off-by: Jesse Gross <jesse@nicira.com>
This patch adds support for skb mark matching and set action.
Acked-by: Jesse Gross <jesse@nicira.com>
Signed-off-by: Ansis Atteka <aatteka@nicira.com>
The names for the flags used by flow based tunneling are pretty long.
This shortens them a little by removing the word FLOW, which is a
distinction that won't be meaningful in the near future.
Signed-off-by: Jesse Gross <jesse@nicira.com>
Acked-by: Kyle Mestery <kmestery@cisco.com>
