Network A. Antony
Internet-Draft secunet
Intended status: Standards Track T. Brunner
Expires: 13 January 2022 codelabs
S. Klassert
secunet
P. Wouters
Aiven
12 July 2021
IKEv2 support for per-queue Child SAs
draft-pwouters-ipsecme-multi-sa-performance-00
Abstract
This document defines four Notify Message Type Payloads for the
Internet Key Exchange Protocol Version 2 (IKEv2) indicating support
for the negotiation of multiple identical Child SAs to optimize
performance.
The CPU_QUEUES notification indicates support for multiple queues or
CPUs. The QOS_QUEUES notification indicates support for different
Quality of Service (QoS) levels. The CPU_QUEUE_INFO and
QOS_QUEUE_INFO notification are used to confirm and optionally convey
information about the specific queue, such as QoS level.
Using multiple identical Child SAs has the benefit that each stream
has its own Sequence Number Counter, ensuring that CPUs don't have to
synchronize their crypto state or disable their packet replay
protection.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
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material or to cite them other than as "work in progress."
This Internet-Draft will expire on 13 January 2022.
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Copyright Notice
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3
2. Performance bottlenecks . . . . . . . . . . . . . . . . . . . 4
3. Negotiation of CPU specific Child SAs . . . . . . . . . . . . 4
4. Negotiation of QoS specific Child SAs . . . . . . . . . . . . 6
5. Implementation specifics . . . . . . . . . . . . . . . . . . 6
5.1. per-CPU Child SAs . . . . . . . . . . . . . . . . . . . . 6
5.2. per-QoS Child SAs . . . . . . . . . . . . . . . . . . . . 7
5.3. Combining per-CPU and per-QoS level Child SAs . . . . . . 8
6. Payload Format . . . . . . . . . . . . . . . . . . . . . . . 8
6.1. CPU_QUEUES Notify Message Payload . . . . . . . . . . . . 8
6.2. QOS_QUEUES Notify Message Payload . . . . . . . . . . . . 9
6.3. CPU_QUEUE_INFO Notify Message Payload . . . . . . . . . . 9
6.4. QOS_QUEUE_INFO Notify Message Payload . . . . . . . . . . 10
7. Operational Considerations . . . . . . . . . . . . . . . . . 11
8. Security Considerations . . . . . . . . . . . . . . . . . . . 12
9. Implementation Status . . . . . . . . . . . . . . . . . . . . 12
9.1. Linux XFRM . . . . . . . . . . . . . . . . . . . . . . . 13
9.2. Libreswan . . . . . . . . . . . . . . . . . . . . . . . . 14
9.3. strongSwan . . . . . . . . . . . . . . . . . . . . . . . 14
9.4. iproute2 . . . . . . . . . . . . . . . . . . . . . . . . 15
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 15
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 15
11.1. Normative References . . . . . . . . . . . . . . . . . . 15
11.2. Informative References . . . . . . . . . . . . . . . . . 16
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16
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1. Introduction
IPsec implementations are currently limited to using one queue or CPU
per Child SA. The result is that a machine with many queues/CPUs is
limited to only using one of these per Child SA. This severely
limits the throughput that can be attained. An unencrypted link of
10Gbps or more is commonly reduced to 2-5Gbps when IPsec is used to
encrypt the link using AES-GCM. By using the implementation
specified in this document, aggregate throughput increased from 5Gbps
using 1 CPU to 40-60 Gbps using 25-30 CPUs
Furthermore, IPsec implementations are currently limited to use the
same Child SA for all Quality of Service (QoS) types because the QoS
type is not a part of the Traffic Selector (TS) payload. The result
is that IPsec cannot support active Quality of Service prioritization
without disabling the anti-replay protection.
While this could be (partially) mitigated by setting up multiple
narrowed Child SAs, for example using Populate From Packet (PFP) as
specified in [RFC4301], this IPsec feature is not widely implemented.
Some route based IPsec implementations might be able to implement
this with specific rules into separate network interfaces, but these
methods might not be available for policy based IPsec
implementations.
To make better use of multiple network queues and CPUs, it can be
beneficial to negotiate and install multiple identical Child SAs.
IKEv2 [RFC7296] already allows installing multiple identical Child
SAs, it offers no method to negotiate the number of Child SAs or
indicate the purpose for the multiple Child SAs that are requested.
When two IKEv2 peers want to negotiate multiple Child SAs, it is
useful to be able to convey how many Child SAs are required for
optimized traffic. This avoids triggering CREATE_CHILD_SA exchanges
that will only be rejected by the peer.
1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here.
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2. Performance bottlenecks
Currently, most IPsec implementations are limited by using one CPU or
network queue per Child SA. There are a number of practical reasons
for this, but a key limitation is that sharing the crypto state,
counters and sequence numbers between multiple CPUs is not feasible
without a significant performance penalty. There is a need to
negotiate and establish multiple Child SAs with identical TSi/TSr on
a per-queue or per-CPU basis.
3. Negotiation of CPU specific Child SAs
When negotiating CPU specific Child SAs, the first SA negotiated
either in an IKE_AUTH exchange or CREATE_CHILD_SA is called Fallback
SA. This Child SA is similar to a regular Cgild SA in that it is not
bound to a single resource (CPU or QoS queue). This Fallback Child
SA (or its rekeyed successors) MUST remain active for the lifetime of
the IPsec session to ensure that there is always a Child SA that can
be selected to send traffic over, in case a per-resource Child SA is
not available. Additional Child SAs are installed bound to a
specific resource (CPU or QoS queue). These Child SAs are
responsible for the bulk of the traffic.
The CPU_QUEUES notification payload is sent in the IKE_AUTH or
CREATE_CHILD_SA Exchange indicating the negotiated Child SA is a
Fallback SA.
The CPU_QUEUES notification value refers to the number of additional
resource-specific Child SAs that may be installed for this particular
TSi/TSr combination excluding the Fallback Child SA. Both peers send
the preferred minimum number of additional Child SAs to install.
Both peers pick the maximum of the two numbers (within reason). That
is, if the initiator prefers 16 and the responder prefers 48, then
the number negotiated is 48. The responder may at any time reject
additional Child SAs by returning TS_UNACCEPTABLE. It should not
return NO_ADDITIONAL_SAS, as there might be another Child SAs with
different Traffic Selectors that would still be allowed by the peer.
[Antony: Valery's feedback was not to use TS_UNACCEPTABLE. instead
create a new notify or use TEMPORARY_FAILURE. TEMPORARY_FAILURE
because the situation may change again if you try again. I have
preference to define new NO_CPU_QUEUE_INFO_SA]
Resource-specific Child SAs are negotiated as regular Child SAs using
the CREATE_CHILD_SA exchange and are identified by a CPU_QUEUE_INFO
notification. Upon installation, each Child SA is associated with an
additional local selector, such as CPU or queue. These additional
Child SAs MUST be negotiated with identical Child SA properties that
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were negotiated for the Fallback SA. This includes cryptographic
algorithms, Traffic Selectors, Mode (e.g. transport mode),
compression usage, etc. However, the Child SAs do have their own
individual keying material that is derived according to the regular
IKEv2 process. The CPU_QUEUE_INFO can be empty or contain some
identifying data that could be useful for debugging purposes.
Additional Child SAs can be started on-demand or can be started all
at once. Peers may also delete specific per-resource Child SAs if
they deem the associated resource to be idle. The Fallback SA MUST
NOT be deleted while any per-resource Child SAs are still present.
During the CREATE_CHILD_SA rekey for the Child SA, the CPU_QUEUE_INFO
notification MAY be included, but regardless of whether or not it is
included, the rekeyed Child SA MUST be bound to the same resource(s)
as the Child SA that is being rekeyed.
As with regular Child SA rekeying, the new Child SA may not be
different from the rekeyed Child SA with respect to cryptographic
algorithms and MUST cover the original Traffic Selector ranges.
If a CREATE_CHILD_SA exchange request containing both a
CPU_QUEUE_INFO and a CPU_QUEUES notification is received, the
responder MUST ignore the CPU_QUEUE_INFO payload. If a
CREATE_CHILD_SA exchange reply is received with both CPU_QUEUE_INFO
and CPU_QUEUES notifications, the initiator MUST ignore the
notification that it did not send in the request.
[Steffen: I tend to tread these cases as an error.]
[Tobias: That's currently how I implemented it (being lenient on what
I accept). But we could also treat those cases as errors. The
question would just be what we should return (NO_PROPOSAL_CHOSEN and
keep IKE and other Child SAs or even INALID_SYNTAX and kill the whole
IKE_SA - and as initiator we either have to terminate the Child or
the IKE_SA actively if we receive both notifies).]
The CPU_QUEUES notification, even when it is sent in the IKE_AUTH
exchange, is not an attribute of the IKE peer. It is an attribute of
the Child SA, similar to the USE_TRANSPORT notification. That is, an
IKE peer can have multiple Child SAs covering different traffic
selectors and selectively decide whether or not to enable additional
per-resource Child SAs for each of these Child SAs covering different
Traffic Selectors.
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4. Negotiation of QoS specific Child SAs
To install multiple Child SAs for different QoS levels, a similar
negotiation method is used. The QOS_QUEUES notification is sent with
the negotiation of the Fallback Child SA that is used for all QoS
levels not matched by more specific Child SAs. Additional Child SAs
are installed per QoS level by including the QOS_QUEUE_INFO
notification describing the specific QoS level that this additional
Child SA will cover. This allows both peers to install the Child SA
using the same QoS level.
[Steffen: Maybe mention IPv6 flow label too]
If a certain QoS level proposed by the peer is not acceptable to the
responder, TS_UNACCEPTABLE MUST be returned.
[Tobias: Would a more specific error notify make sense here?]
[Antony: We need specific error if is rejected QOS_QUEUE_INFO]
5. Implementation specifics
There are various considerations that an implementation can use to
determine the best way to install multiple Child SAs. Below are
examples of such strategies.
5.1. per-CPU Child SAs
A simple distribution could be to install one additional Child SA on
each CPU. The Fallback Child SA ensures that any CPU generating
traffic to be encrypted has an available (if not optimal) Child SA to
use. Any subsequent Child SAs with identical TSi/TSr Traffic
Selectors are installed in such a way to only be used by a single CPU
or network queue.
Performing per-CPU Child SA negotiations can result in both peers
initiating additional Child SAs at once. This is especially likely
if per-CPU Child SAs are triggered by individual SADB_ACQUIRE
[RFC2367] messages. Responders should install the additional Child
SA on a CPU with the least amount of additional Child SAs for this
TSi/TSr pair. It should count outstanding SADB_ACQUIREs as an
assigned additional Child SA. It is still possible that when the
peers only have one slot left to assign, that both peers send a
CREATE_CHILD_SA request at the same time. [Paul: Is there anything
we can do at the protocol level to terminate one of these without
race conditions?] [Antony: if CPU_QUEUE_INFO is a MUST, that info
could be used for better one-to-one mapping, as well as delete the
extra SAs. Also, keep in mind the general case IKE window > 1]
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As an optimization, additional Child SAs that see little traffic MAY
be deleted. The Fallback Child SA MUST NOT be deleted when idle, as
it is likely to be idle if enough per-CPU Child SAs are installed.
However, if one of those per-CPU child SAs is deleted because it was
idle, and subsequently that CPU starts to generate traffic again,
that traffic does not have a per-CPU Child SA and will be encrypted
using the Fallback Child SA. Meanwhile, the IKE daemon might be
negotiating to bring up a new per-CPU Child SA.
When the number of queues or CPUs are different between the peers,
the peer with the least amount of queues or CPUs MAY decide to not
install a second outbound Child SA for the same resource as it will
never use it to send traffic. However, it MUST install all inbound
Child SAs as it has committed to receiving traffic on these
negotiated Child SAs.
If per-CPU SADB_ACQUIRE messages are implemented (see Section 7), the
Traffic Selector (TSi) entry containing the information of the
trigger packet should still be included in the TS set. This
information MAY be used by the peer to select the most optimal target
CPU to install the additional Child SA on. For example, if the
trigger packet was for a TCP destination to port 25 (SMTP), it might
be able to install the Child SA on the CPU that is also running the
mail server process. Trigger packet Traffic Selectors are documented
in [RFC7296] Section 2.9.
As per RFC 7296, rekeying a Child SA SHOULD use the same (or wider)
Traffic Selectors to ensure that the new Child SA covers everything
that the rekeyed Child SA covers. This includes Traffic Selectors
negotiated via Configuration Payloads (CP) such as
INTERNAL_IP4_ADDRESS which may use the original wide TS set or use
the narrowed TS set.
5.2. per-QoS Child SAs
[Paul: is there anything we need to say here?]
[Steffen: If we want to say something about that case, maybe this:]
Most considerations from the per-CPU case apply to the per-QoS case
as well. The main difference between these two cases is that the
number of possible QoS types are always the same for both peers (e.g.
64 types for IPv4). Unlike the per-CPU case, handling different
numbers of QoS types is not necessary.
[Paul: I was hoping we could negotiate things like "only 2 different
levels needed", and not just a "we want to install SAs for all
theoretical possible levels"]
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5.3. Combining per-CPU and per-QoS level Child SAs
It is unlikely but not disallowed, to use both per CPU and per QoS
level Child SAs. Any conflicts between the performance improving
types of SAs would need to be handled by local policies. For some,
the QoS might be more important to honour as best as possible, while
for others, CPU distribution might be more important. There is
currently no operational experience with combining these two types of
Child SAs.
[Tobias: How would this look like? Would you send both notifies on
the same set of SAs (CPU/QOS_QUEUE on the fallback SA and INFO on the
others)? (So each SA would be for a specific CPU AND QoS class.) Or
would you negotiate separate per-CPU and per-QoS SAs all with the
same TS? (e.g. if you already bound certain classes to certain CPUs
anyway and use a QoS specific SA for that, but still want to use
multiple CPUs for the other traffic and negotiate per-CPU SAs without
QoS identifier for that)]
[Paul: I don't really know - perhaps we should remove QoS until we
have someone who actually wants to run this and can provide guidance
for standardization ? ]
6. Payload Format
All multi-octet fields representing integers are laid out in big
endian order (also known as "most significant byte first", or
"network byte order").
6.1. CPU_QUEUES Notify Message Payload
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-----------------------------+-------------------------------+
! Next Payload !C! RESERVED ! Payload Length !
+---------------+---------------+-------------------------------+
! Protocol ID ! SPI Size ! Notify Message Type !
+---------------+---------------+-------------------------------+
! Minimum number of IPsec SAs !
+-------------------------------+-------------------------------+
* Protocol ID (1 octet) - MUST be 0. MUST be ignored if not 0.
* SPI Size (1 octet) - MUST be 0. MUST be ignored if not 0.
* Notify Message Type (2 octets) - set to [TBD1]
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* Minimum number of per-CPU IPsec SAs (4 octets). MUST be greater
than 0. If 0 is received, it MUST be interpreted as 1.
Note: The Fallback Child SA that is not bound to a single CPU is not
counted as part of these numbers.
6.2. QOS_QUEUES Notify Message Payload
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-----------------------------+-------------------------------+
! Next Payload !C! RESERVED ! Payload Length !
+---------------+---------------+-------------------------------+
! Protocol ID ! SPI Size ! Notify Message Type !
+---------------+---------------+-------------------------------+
! Minimum number of IPsec SAs !
+-------------------------------+-------------------------------+
* Protocol ID (1 octet) - MUST be 0. MUST be ignored if not 0.
* SPI Size (1 octet) - MUST be 0. MUST be ignored if not 0.
* Notify Message Type (2 octets) - set to [TBD2]
* Maximum number of QoS level IPsec SAs (4 octets). MUST be greater
than 0. If 0 is received, it MUST be interpreted as 1.
* [Steffen: Does it make sense to negotiate the max. number of QoS
types? Unlike the per-CPU case, there is no tradeoff between the
peers. Both peers always support the same number of QoS types (64
on IPv4)]
* [Tobias: I agree with Steffen. This doesn't seem necessary and
might even be confusing as reducing the number would not tell the
peer what classes should actually be sent.]
* [Paul: I was hoping to send the desired number of different
levels, not the theoretical maximum of used levels
Note: The Fallback Child SA that is not bound to a single QoS is not
counted as part of these numbers.
6.3. CPU_QUEUE_INFO Notify Message Payload
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1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-----------------------------+-------------------------------+
! Next Payload !C! RESERVED ! Payload Length !
+---------------+---------------+-------------------------------+
! Protocol ID ! SPI Size ! Notify Message Type !
+---------------+---------------+-------------------------------+
! !
~ Optional queue identifier ~
! !
+-------------------------------+-------------------------------+
* Protocol ID (1 octet) - MUST be 0. MUST be ignored if not 0.
* SPI Size (1 octet) - MUST be 0. MUST be ignored if not 0.
* Notify Message Type (2 octets) - set to [TBD3]
* Optional Payload Data. This value MAY be set to convey the local
identity of the queue. The value SHOULD be a unique identifier
and the peer SHOULD only use it for debugging purposes.
6.4. QOS_QUEUE_INFO Notify Message Payload
1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-----------------------------+-------------------------------+
! Next Payload !C! RESERVED ! Payload Length !
+---------------+---------------+-------------------------------+
! Protocol ID ! SPI Size ! Notify Message Type !
+---------------+---------------+-------------------------------+
! !
~ Mandatory QoS level specifier ~
! !
+-------------------------------+-------------------------------+
* Protocol ID (1 octet) - MUST be 0. MUST be ignored if not 0.
* SPI Size (1 octet) - MUST be 0. MUST be ignored if not 0.
* Notify Message Type (2 octets) - set to [TBD4] Mandatory Payload
Data. This value MUST be set to identify the QoS level. [Paul:
Can we say 'one byte for each level of QoS included for this SA'
?] [Steffen: I don't understand that? Do we support more than one
QoS type per SA? I think we need space to cover either a 6 bit
IPv4 QoS type or a 20 bit IPv6 flow label.] [Tobias: Hm, one
problem here is that CHILD_SAs can have traffic selectors of both
address families. So how could we negotiate that we need a QoS
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type AND a flow label? Would that require two notifies
(QOS_4|6_QUEUE_INFO types) or could we have two fields in the
notify that may be set to 0? Or should that just not be allowed?
I don't even know if it makes sense and whether QoS classes and
flow labels are combinable in that way (I guess a dual-stack VoIP
client would classify traffic in a comparable way for each
family). And I also wonder if there is a mechanism to apply a
flow label to an outer IPv4 header's TOS field and vice-versa. If
multiple classes/labels should be supported per SA we could also
send multiple notifies (but I guess that would mean that on-path
routers had to treat all these classes/labels the same way, which
begs the question why different values would get assigned to the
packets in the first place).]
7. Operational Considerations
Implementations supporting per-CPU SAs SHOULD extend their local SPD
selector, and the mechanism of on-demand negotiation that is
triggered by traffic to include a CPU (or queue) identifier in their
SADB_ACQUIRE message from the SPD to the IKE daemon. If the IKEv2
extension defined in this document is negotiated with the peer, a
node which does not support receiving per-CPU SADB_ACQUIRE messages
MAY initiate all its Child SAs immediately upon receiving the (only)
SADB_ACQUIRE it will receive from the IPsec stack. Such
implementations also need to be careful when receiving a Delete
Notify request for a per-CPU Child SA, as it has no method to detect
when it should bring up such a per-CPU Child SA again later. And
bringing the deleted per-CPU Child SA up again immediately after
receiving the Delete Notify might cause an infinite loop between the
peers. Another issue of not bringing up all its per-CPU Child SAs is
that if the peer acts similarly, the two peers might end up with only
the Fallback SA without ever activating any per-CPU Child SAs. It is
there for RECOMMENDED to implement per-CPU SADB_ACQUIRE messages. [
Antony: It would be nice to add manual/scripts for starting of
connection and bringing up per-CPU SAs. It could be very simple, a
external program decides to start a per-CPU SA. ]
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The minimum number of Child SAs negotiated should not be treated as
the maximum number of allowed Child SAs. Peers SHOULD be lenient
with this number to account for corner cases. For example, during
Child SA rekeying, there might be a large number of additional Child
SAs created before the old Child SAs are torn down. Similarly, when
using on-demand Child SAs, both ends could trigger multiple Child SA
requests as the initial packet causing the Child SA negotiation might
have been transported to the peer via the Fallback SA where its reply
packet might also trigger an on-demand Child SA negotiation to start.
A peer may want to allow up to double the negotiated minimum number
of Child SAs, and rely on idleness of Child SAs to tear down any
unused Child SAs gradually to to reach an optimal number of Child
SAs. Adding too many SAs may slow down per-packet SAD lookup.
Implementations might support dynamically moving a per-CPU Child SAs
from one CPU to another CPU. If this method is supported,
implementations must be careful to move both the inbound and outbound
SAs. If the IPsec endpoint is a gateway, it can move the inbound SA
and outbound SA independently from each other. It is likely that for
a gateway, IPsec traffic would be asymmetric. If the IPsec endpoint
is the same host responsible for generating the traffic, the inbound
and outbound SAs SHOULD remain as a pair on the same CPU. If a host
previously skipped installing an outbound SA because it would be an
unused duplicate outbound SA, it will have to create and add the
previously skipped outbound SA to the SAD with the new CPU ID. The
inbound SA may not have CPU ID in the SAD. Adding the outbound SA to
the SAD requires access to the key material, whereas for updating the
CPU selector on an existing outbound SAs. access to key material
might not be needed. To support this, the IKE software might have to
hold on to the key material longer than it normally would, as it
might actively attempt to destroy key material from memorya that it
no longer needs access to.
8. Security Considerations
[TO DO]
9. Implementation Status
[Note to RFC Editor: Please remove this section and the reference to
[RFC6982] before publication.]
This section records the status of known implementations of the
protocol defined by this specification at the time of posting of this
Internet-Draft, and is based on a proposal described in [RFC7942].
The description of implementations in this section is intended to
assist the IETF in its decision processes in progressing drafts to
RFCs. Please note that the listing of any individual implementation
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here does not imply endorsement by the IETF. Furthermore, no effort
has been spent to verify the information presented here that was
supplied by IETF contributors. This is not intended as, and must not
be construed to be, a catalog of available implementations or their
features. Readers are advised to note that other implementations may
exist.
According to [RFC7942], "this will allow reviewers and working groups
to assign due consideration to documents that have the benefit of
running code, which may serve as evidence of valuable experimentation
and feedback that have made the implemented protocols more mature.
It is up to the individual working groups to use this information as
they see fit".
Authors are requested to add a note to the RFC Editor at the top of
this section, advising the Editor to remove the entire section before
publication, as well as the reference to [RFC7942].
9.1. Linux XFRM
Organization: Linux kernel XFRM
Name: XFRM-PCPU-v1
https://git.kernel.org/pub/scm/linux/kernel/git/klassert/linux-
stk.git/log/?h=xfrm-pcpu-v1
Description: An initial Kernel IPsec implementation of the per-CPU
method.
Level of maturity: Alpha
Coverage: Implements Fallback Child SA and per-CPU Child SAs. It
only supports the NETLINK API. The PFKEYv2 API is not supported.
Licensing: GPLv2
Implementation experience: The Linux XFRM implementation added two
additional attributes to support per-CPU SAs. There is a new
attribute XFRMA_SA_PCPU, u32, for the SAD entry. This attribute
should present on the outgoing SA, per-CPU Child SAs, starting
from 0. This attribute MUST NOT be present on the Fallback XFRM
SA. It is used by the kernel only for the outgoing traffic,
(clear to encrypted). The incoming SAs, both the Fallback and the
per-CPU SA, do not need XFRMA_SA_PCPU attribute. XFRM stack can
not use CPU id on the incoming SA. The kernel internally sets the
value to 0xFFFFFF for the incoming SA and the Fallback SA.
However, one may add XFRMA_SA_PCPU to the incoming per-CPU SA to
steer the ESP flow, to a specific Q or CPU e.g ethtool ntuple
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configuration. The SPD entry has new flag
XFRM_POLICY_CPU_ACQUIRE. It should be set only on the "out"
policy. The flag should be disabled when the policy is a trap
policy, without SPD entries. After a successful negotiation of
CPU_QUEUES, while adding the Fallback Child SA, the SPD entry can
be updated with the XFRM_POLICY_CPU_ACQUIRE flag. When
XFRM_POLICY_CPU_ACQUIRE is set, the XFRM_MSG_ACQUIRE generated
will include the XFRMA_SA_PCPU attribute.
Contact: Steffen Klassert steffen.klassert@secunet.com
9.2. Libreswan
Organization: The Libreswan Project
Name: pcpu-3 https://libreswan.org/wiki/XFRM_pCPU
Description: An initial IKE implementation of the per-CPU method.
Level of maturity: Alpha
Coverage: implements Fallback Child SA and per-CPU additional Child
SAs
Licensing: GPLv2
Implementation experience: TBD
Contact: Libreswan Development: swan-dev@libreswan.org
9.3. strongSwan
Organization: The StrongSwan Project
Name: StrongSwan https://github.com/strongswan/strongswan/tree/per-
cpu-sas-poc/
Description: An initial IKE implementation of the per-CPU method.
Level of maturity: Alpha
Coverage: implements Fallback Child SA and per-CPU additional Child
SAs
Licensing: GPLv2
Implementation experience: StrongSwan use private space values for
notifications CPU_QUEUES (40970) and QUEUE_INFO (40971).
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Contact: Tobias Brunner tobias@strongswan.org
9.4. iproute2
Organization: The iproute2 Project
Name: iproute2 https://github.com/antonyantony/iproute2/tree/pcpu-v1
Description: Implemented the per-CPU attributes for the "ip xfrm"
command.
Level of maturity: Alpha
Licensing: GPLv2
Implementation experience: TBD
Contact: Antony Antony antony.antony@secunet.com
10. IANA Considerations
This document defines four new IKEv2 Notify Message Type payloads for
the IANA "IKEv2 Notify Message Types - Status Types" registry.
Value Notify Type Messages - Status Types Reference
----- ------------------------------ ---------------
[TBD1] CPU_QUEUES [this document]
[TBD2] QOS_QUEUES [this document]
[TBD3] CPU_QUEUE_INFO [this document]
[TBD4] QOS_QUEUE_INFO [this document]
Figure 1
11. References
11.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC2367] McDonald, D., Metz, C., and B. Phan, "PF_KEY Key
Management API, Version 2", RFC 2367,
DOI 10.17487/RFC2367, July 1998,
<https://www.rfc-editor.org/info/rfc2367>.
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[RFC7296] Kaufman, C., Hoffman, P., Nir, Y., Eronen, P., and T.
Kivinen, "Internet Key Exchange Protocol Version 2
(IKEv2)", STD 79, RFC 7296, DOI 10.17487/RFC7296, October
2014, <https://www.rfc-editor.org/info/rfc7296>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
11.2. Informative References
[RFC4301] Kent, S. and K. Seo, "Security Architecture for the
Internet Protocol", RFC 4301, DOI 10.17487/RFC4301,
December 2005, <https://www.rfc-editor.org/info/rfc4301>.
[RFC6982] Sheffer, Y. and A. Farrel, "Improving Awareness of Running
Code: The Implementation Status Section", RFC 6982,
DOI 10.17487/RFC6982, July 2013,
<https://www.rfc-editor.org/info/rfc6982>.
[RFC7942] Sheffer, Y. and A. Farrel, "Improving Awareness of Running
Code: The Implementation Status Section", BCP 205,
RFC 7942, DOI 10.17487/RFC7942, July 2016,
<https://www.rfc-editor.org/info/rfc7942>.
Authors' Addresses
Antony Antony
secunet Security Networks AG
Email: antony.antony@secunet.com
Tobias Brunner
codelabs GmbH
Email: tobias@codelabs.ch
Steffen Klassert
secunet Security Networks AG
Email: steffen.klassert@secunet.com
Paul Wouters
Aiven
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Email: paul.wouters@aiven.io
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