< draft-ietf-dots-signal-channel-26.txt   draft-ietf-dots-signal-channel-27.txt >
DOTS T. Reddy, Ed. DOTS T. Reddy, Ed.
Internet-Draft McAfee Internet-Draft McAfee
Intended status: Standards Track M. Boucadair, Ed. Intended status: Standards Track M. Boucadair, Ed.
Expires: June 24, 2019 Orange Expires: July 22, 2019 Orange
P. Patil P. Patil
Cisco Cisco
A. Mortensen A. Mortensen
Arbor Networks, Inc. Arbor Networks, Inc.
N. Teague N. Teague
Verisign, Inc. Verisign, Inc.
December 21, 2018 January 18, 2019
Distributed Denial-of-Service Open Threat Signaling (DOTS) Signal Distributed Denial-of-Service Open Threat Signaling (DOTS) Signal
Channel Specification Channel Specification
draft-ietf-dots-signal-channel-26 draft-ietf-dots-signal-channel-27
Abstract Abstract
This document specifies the DOTS signal channel, a protocol for This document specifies the DOTS signal channel, a protocol for
signaling the need for protection against Distributed Denial-of- signaling the need for protection against Distributed Denial-of-
Service (DDoS) attacks to a server capable of enabling network Service (DDoS) attacks to a server capable of enabling network
traffic mitigation on behalf of the requesting client. traffic mitigation on behalf of the requesting client.
A companion document defines the DOTS data channel, a separate A companion document defines the DOTS data channel, a separate
reliable communication layer for DOTS management and configuration reliable communication layer for DOTS management and configuration
skipping to change at page 2, line 5 skipping to change at page 2, line 5
o reference: RFC XXXX o reference: RFC XXXX
Please update this statement with the RFC number to be assigned to Please update this statement with the RFC number to be assigned to
the following documents: the following documents:
o "RFC YYYY: Distributed Denial-of-Service Open Threat Signaling o "RFC YYYY: Distributed Denial-of-Service Open Threat Signaling
(DOTS) Data Channel Specification (used to be (DOTS) Data Channel Specification (used to be
[I-D.ietf-dots-data-channel]) [I-D.ietf-dots-data-channel])
Please update TBD statements with the port number to be assigned to Please update TBD/TBD1/TBD2 statements with the assignments made by
DOTS Signal Channel Protocol. IANA to DOTS Signal Channel Protocol.
Also, please update the "revision" date of the YANG modules. Also, please update the "revision" date of the YANG modules.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on June 24, 2019. This Internet-Draft will expire on July 22, 2019.
Copyright Notice Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2019 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of (https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
skipping to change at page 3, line 4 skipping to change at page 3, line 4
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 6 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 6
3. Design Overview . . . . . . . . . . . . . . . . . . . . . . . 6 3. Design Overview . . . . . . . . . . . . . . . . . . . . . . . 6
4. DOTS Signal Channel: Messages & Behaviors . . . . . . . . . . 9 4. DOTS Signal Channel: Messages & Behaviors . . . . . . . . . . 9
4.1. DOTS Server(s) Discovery . . . . . . . . . . . . . . . . 9 4.1. DOTS Server(s) Discovery . . . . . . . . . . . . . . . . 9
4.2. CoAP URIs . . . . . . . . . . . . . . . . . . . . . . . . 9 4.2. CoAP URIs . . . . . . . . . . . . . . . . . . . . . . . . 9
4.3. Happy Eyeballs for DOTS Signal Channel . . . . . . . . . 9 4.3. Happy Eyeballs for DOTS Signal Channel . . . . . . . . . 9
4.4. DOTS Mitigation Methods . . . . . . . . . . . . . . . . . 11 4.4. DOTS Mitigation Methods . . . . . . . . . . . . . . . . . 11
4.4.1. Request Mitigation . . . . . . . . . . . . . . . . . 12 4.4.1. Request Mitigation . . . . . . . . . . . . . . . . . 12
4.4.2. Retrieve Information Related to a Mitigation . . . . 27 4.4.2. Retrieve Information Related to a Mitigation . . . . 26
4.4.2.1. DOTS Servers Sending Mitigation Status . . . . . 31 4.4.2.1. DOTS Servers Sending Mitigation Status . . . . . 31
4.4.2.2. DOTS Clients Polling for Mitigation Status . . . 34 4.4.2.2. DOTS Clients Polling for Mitigation Status . . . 34
4.4.3. Efficacy Update from DOTS Clients . . . . . . . . . . 35 4.4.3. Efficacy Update from DOTS Clients . . . . . . . . . . 35
4.4.4. Withdraw a Mitigation . . . . . . . . . . . . . . . . 37 4.4.4. Withdraw a Mitigation . . . . . . . . . . . . . . . . 37
4.5. DOTS Signal Channel Session Configuration . . . . . . . . 38 4.5. DOTS Signal Channel Session Configuration . . . . . . . . 38
4.5.1. Discover Configuration Parameters . . . . . . . . . . 40 4.5.1. Discover Configuration Parameters . . . . . . . . . . 40
4.5.2. Convey DOTS Signal Channel Session Configuration . . 44 4.5.2. Convey DOTS Signal Channel Session Configuration . . 44
4.5.3. Configuration Freshness and Notifications . . . . . . 49 4.5.3. Configuration Freshness and Notifications . . . . . . 49
4.5.4. Delete DOTS Signal Channel Session Configuration . . 50 4.5.4. Delete DOTS Signal Channel Session Configuration . . 50
4.6. Redirected Signaling . . . . . . . . . . . . . . . . . . 51 4.6. Redirected Signaling . . . . . . . . . . . . . . . . . . 51
4.7. Heartbeat Mechanism . . . . . . . . . . . . . . . . . . . 53 4.7. Heartbeat Mechanism . . . . . . . . . . . . . . . . . . . 53
5. DOTS Signal Channel YANG Modules . . . . . . . . . . . . . . 54 5. DOTS Signal Channel YANG Modules . . . . . . . . . . . . . . 54
5.1. Tree Structure . . . . . . . . . . . . . . . . . . . . . 54 5.1. Tree Structure . . . . . . . . . . . . . . . . . . . . . 54
5.2. IANA DOTS Signal Channel YANG Module . . . . . . . . . . 56 5.2. IANA DOTS Signal Channel YANG Module . . . . . . . . . . 56
5.3. IETF DOTS Signal Channel YANG Module . . . . . . . . . . 60 5.3. IETF DOTS Signal Channel YANG Module . . . . . . . . . . 60
6. Mapping Parameters to CBOR . . . . . . . . . . . . . . . . . 70 6. YANG/JSON Mapping Parameters to CBOR . . . . . . . . . . . . 70
7. (D)TLS Protocol Profile and Performance Considerations . . . 72 7. (D)TLS Protocol Profile and Performance Considerations . . . 73
7.1. (D)TLS Protocol Profile . . . . . . . . . . . . . . . . . 72 7.1. (D)TLS Protocol Profile . . . . . . . . . . . . . . . . . 73
7.2. (D)TLS 1.3 Considerations . . . . . . . . . . . . . . . . 74 7.2. (D)TLS 1.3 Considerations . . . . . . . . . . . . . . . . 74
7.3. MTU and Fragmentation . . . . . . . . . . . . . . . . . . 75 7.3. DTLS MTU and Fragmentation . . . . . . . . . . . . . . . 75
8. Mutual Authentication of DOTS Agents & Authorization of DOTS 8. Mutual Authentication of DOTS Agents & Authorization of DOTS
Clients . . . . . . . . . . . . . . . . . . . . . . . . . . . 76 Clients . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 78 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 78
9.1. DOTS Signal Channel UDP and TCP Port Number . . . . . . . 78 9.1. DOTS Signal Channel UDP and TCP Port Number . . . . . . . 78
9.2. Well-Known 'dots' URI . . . . . . . . . . . . . . . . . . 78 9.2. Well-Known 'dots' URI . . . . . . . . . . . . . . . . . . 78
9.3. Media Type Registration . . . . . . . . . . . . . . . . . 78 9.3. Media Type Registration . . . . . . . . . . . . . . . . . 78
9.3.1. Registry Contents . . . . . . . . . . . . . . . . . . 78
9.4. CoAP Content-Formats Registration . . . . . . . . . . . . 79 9.4. CoAP Content-Formats Registration . . . . . . . . . . . . 79
9.4.1. Registry Contents . . . . . . . . . . . . . . . . . . 79
9.5. CBOR Tag Registration . . . . . . . . . . . . . . . . . . 79 9.5. CBOR Tag Registration . . . . . . . . . . . . . . . . . . 79
9.5.1. Registry Contents . . . . . . . . . . . . . . . . . . 80
9.6. DOTS Signal Channel Protocol Registry . . . . . . . . . . 80 9.6. DOTS Signal Channel Protocol Registry . . . . . . . . . . 80
9.6.1. DOTS Signal Channel CBOR Mappings Sub-Registry . . . 80 9.6.1. DOTS Signal Channel CBOR Key Values Sub-Registry . . 80
9.6.1.1. Registration Template . . . . . . . . . . . . . . 81 9.6.1.1. Registration Template . . . . . . . . . . . . . . 80
9.6.1.2. Initial Sub-Registry Content . . . . . . . . . . 81 9.6.1.2. Initial Sub-Registry Content . . . . . . . . . . 81
9.6.2. Status Codes Sub-Registry . . . . . . . . . . . . . . 83 9.6.2. Status Codes Sub-Registry . . . . . . . . . . . . . . 82
9.6.3. Conflict Status Codes Sub-Registry . . . . . . . . . 84 9.6.3. Conflict Status Codes Sub-Registry . . . . . . . . . 84
9.6.4. Conflict Cause Codes Sub-Registry . . . . . . . . . . 86 9.6.4. Conflict Cause Codes Sub-Registry . . . . . . . . . . 86
9.6.5. Attack Status Codes Sub-Registry . . . . . . . . . . 86 9.6.5. Attack Status Codes Sub-Registry . . . . . . . . . . 86
9.7. DOTS Signal Channel YANG Modules . . . . . . . . . . . . 87 9.7. DOTS Signal Channel YANG Modules . . . . . . . . . . . . 87
10. Security Considerations . . . . . . . . . . . . . . . . . . . 88 10. Security Considerations . . . . . . . . . . . . . . . . . . . 88
11. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 89 11. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 90
12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 90 12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 90
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 90 13. References . . . . . . . . . . . . . . . . . . . . . . . . . 90
13.1. Normative References . . . . . . . . . . . . . . . . . . 90 13.1. Normative References . . . . . . . . . . . . . . . . . . 90
13.2. Informative References . . . . . . . . . . . . . . . . . 92 13.2. Informative References . . . . . . . . . . . . . . . . . 93
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 96 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 97
1. Introduction 1. Introduction
A distributed denial-of-service (DDoS) attack is an attempt to make A distributed denial-of-service (DDoS) attack is a distributed
machines or network resources unavailable to their intended users. attempt to make machines or network resources unavailable to their
In most cases, sufficient scale can be achieved by compromising intended users. In most cases, sufficient scale for an effective
enough end-hosts and using those infected hosts to perpetrate and attack can be achieved by compromising enough end-hosts and using
amplify the attack. The victim in this attack can be an application those infected hosts to perpetrate and amplify the attack. The
server, a host, a router, a firewall, or an entire network. victim in this attack can be an application server, a host, a router,
a firewall, or an entire network.
Network applications have finite resources like CPU cycles, the Network applications have finite resources like CPU cycles, the
number of processes or threads they can create and use, the maximum number of processes or threads they can create and use, the maximum
number of simultaneous connections it can handle, the limited number of simultaneous connections they can handle, the limited
resources of the control plane, etc. When processing network resources of the control plane, etc. When processing network
traffic, such applications are supposed to use these resources to traffic, such applications are supposed to use these resources to
offer the intended task in the most efficient manner. However, a provide the intended functionality in the most efficient manner.
DDoS attacker may be able to prevent an application from performing However, a DDoS attacker may be able to prevent an application from
its intended task by making the application exhaust its finite performing its intended task by making the application exhaust its
resources. finite resources.
TCP DDoS SYN-flood, for example, is a memory-exhausting attack while A TCP DDoS SYN-flood [RFC4987], for example, is a memory-exhausting
ACK-flood is a CPU-exhausting attack [RFC4987]. Attacks on the link attack while an ACK-flood is a CPU-exhausting attack. Attacks on the
are carried out by sending enough traffic so that the link becomes link are carried out by sending enough traffic so that the link
congested, thereby likely causing packet loss for legitimate traffic. becomes congested, thereby likely causing packet loss for legitimate
Stateful firewalls can also be attacked by sending traffic that traffic. Stateful firewalls can also be attacked by sending traffic
causes the firewall to maintain an excessive number of states that that causes the firewall to maintain an excessive number of states
may jeopardize the firewall's operation overall, besides likely that may jeopardize the firewall's operation overall, besides likely
performance impacts. The firewall then runs out of memory, and can performance impacts. The firewall then runs out of memory, and can
no longer instantiate the states required to process legitimate no longer instantiate the states required to process legitimate
flows. Other possible DDoS attacks are discussed in [RFC4732]. flows. Other possible DDoS attacks are discussed in [RFC4732].
In many cases, it may not be possible for network administrators to In many cases, it may not be possible for network administrators to
determine the cause(s) of an attack. They may instead just realize determine the cause(s) of an attack. They may instead just realize
that certain resources seem to be under attack. This document that certain resources seem to be under attack. This document
defines a lightweight protocol that allows a DOTS client to request defines a lightweight protocol that allows a DOTS client to request
mitigation from one or more DOTS servers for protection against mitigation from one or more DOTS servers for protection against
detected, suspected, or anticipated attacks. This protocol enables detected, suspected, or anticipated attacks. This protocol enables
cooperation between DOTS agents to permit a highly-automated network cooperation between DOTS agents to permit a highly-automated network
defense that is robust, reliable, and secure. defense that is robust, reliable, and secure. Note that "secure"
means the support of the features defined in Section 2.4 of
[I-D.ietf-dots-requirements].
An example of a network diagram that illustrates a deployment of DOTS An example of a network diagram that illustrates a deployment of DOTS
agents is shown in Figure 1. In this example, a DOTS server is agents is shown in Figure 1. In this example, a DOTS server is
operating on the access network. A DOTS client is located on the LAN operating on the access network. A DOTS client is located on the LAN
(Local Area Network), while a DOTS gateway is embedded in the CPE (Local Area Network), while a DOTS gateway is embedded in the CPE
(Customer Premises Equipment). (Customer Premises Equipment).
Network Network
Resource CPE router Access network __________ Resource CPE router Access network __________
+-----------+ +--------------+ +-------------+ / \ +-----------+ +--------------+ +-------------+ / \
skipping to change at page 7, line 9 skipping to change at page 7, line 9
| IP | | IP |
+---------------------+ +---------------------+
Figure 3: Abstract Layering of DOTS Signal Channel over CoAP over Figure 3: Abstract Layering of DOTS Signal Channel over CoAP over
(D)TLS (D)TLS
By default, a DOTS signal channel MUST run over port number TBD as By default, a DOTS signal channel MUST run over port number TBD as
defined in Section 9.1, for both UDP and TCP, unless the DOTS server defined in Section 9.1, for both UDP and TCP, unless the DOTS server
has a mutual agreement with its DOTS clients to use a different port has a mutual agreement with its DOTS clients to use a different port
number. DOTS clients MAY alternatively support means to dynamically number. DOTS clients MAY alternatively support means to dynamically
discover the ports used by their DOTS servers. In order to use a discover the ports used by their DOTS servers (e.g.,
distinct port number (as opposed to TBD), DOTS clients and servers [I-D.boucadair-dots-server-discovery]). In order to use a distinct
SHOULD support a configurable parameter to supply the port number to port number (as opposed to TBD), DOTS clients and servers SHOULD
use. The rationale for not using the default port number 5684 support a configurable parameter to supply the port number to use.
((D)TLS CoAP) is to allow for differentiated behaviors in The rationale for not using the default port number 5684 ((D)TLS
environments where both a DOTS gateway and an IoT gateway (e.g., CoAP) is to allow for differentiated behaviors in environments where
Figure 3 of [RFC7452]) are present. both a DOTS gateway and an IoT gateway (e.g., Figure 3 of [RFC7452])
are present.
The signal channel uses the "coaps" URI scheme defined in Section 6 The signal channel uses the "coaps" URI scheme defined in Section 6
of [RFC7252] and "coaps+tcp" URI scheme defined in Section 8.2 of of [RFC7252] and the "coaps+tcp" URI scheme defined in Section 8.2 of
[RFC8323] to identify DOTS server resources accessible using CoAP [RFC8323] to identify DOTS server resources accessible using CoAP
over UDP secured with DTLS and CoAP over TCP secured with TLS. over UDP secured with DTLS and CoAP over TCP secured with TLS,
respectively.
The signal channel is initiated by the DOTS client (Section 4.4). The signal channel is initiated by the DOTS client (Section 4.4).
Once the signal channel is established, the DOTS agents periodically Once the signal channel is established, the DOTS agents periodically
send heartbeats to keep the channel active (Section 4.7). At any send heartbeats to keep the channel active (Section 4.7). At any
time, the DOTS client may send a mitigation request message to a DOTS time, the DOTS client may send a mitigation request message to a DOTS
server over the active channel. While mitigation is active because server over the active channel. While mitigation is active (because
of the higher likelihood of packet loss during a DDoS attack, the of the higher likelihood of packet loss during a DDoS attack), the
DOTS server periodically sends status messages to the client, DOTS server periodically sends status messages to the client,
including basic mitigation feedback details. Mitigation remains including basic mitigation feedback details. Mitigation remains
active until the DOTS client explicitly terminates mitigation, or the active until the DOTS client explicitly terminates mitigation, or the
mitigation lifetime expires. mitigation lifetime expires.
DOTS signaling can happen with DTLS over UDP and TLS over TCP. DOTS signaling can happen with DTLS over UDP and TLS over TCP.
Likewise, DOTS requests may be sent using IPv4 or IPv6 transfer Likewise, DOTS requests may be sent using IPv4 or IPv6 transfer
capabilities. A Happy Eyeballs procedure for DOTS signal channel is capabilities. A Happy Eyeballs procedure for DOTS signal channel is
specified in Section 4.3. specified in Section 4.3.
Messages exchanged between DOTS agents are serialized using Concise Messages exchanged between DOTS agents are serialized using Concise
Binary Object Representation (CBOR) [RFC7049], a binary encoding Binary Object Representation (CBOR) [RFC7049], a binary encoding
scheme designed for small code and message size. CBOR-encoded scheme designed for small code and message size. CBOR-encoded
payloads are used to carry signal channel-specific payload messages payloads are used to carry signal channel-specific payload messages
which convey request parameters and response information such as which convey request parameters and response information such as
errors. In order to allow the use of the same data models, [RFC7951] errors. In order to allow reusing data models across protocols,
specifies the JavaScript Object Notation (JSON) encoding of YANG- [RFC7951] specifies the JavaScript Object Notation (JSON) encoding of
modeled data. A similar effort for CBOR is defined in YANG-modeled data. A similar effort for CBOR is defined in
[I-D.ietf-core-yang-cbor]. [I-D.ietf-core-yang-cbor].
DOTS agents determine the CBOR data structure is a DOTS signal DOTS agents primarily determine that a CBOR data structure is a DOTS
channel object from the application context, such as from the port signal channel object from the application context, such as from the
number assigned to the DOTS signal channel. The other method DOTS port number assigned to the DOTS signal channel. The other method
agents use to indicate that a CBOR data structure is a DOTS signal DOTS agents use to indicate that a CBOR data structure is a DOTS
channel object is the use of the "application/dots+cbor" content type signal channel object is the use of the "application/dots+cbor"
(Section 9.3). content type (Section 9.3).
From that standpoint, this document specifies a YANG module for This document specifies a YANG module for representing DOTS
representing DOTS mitigation scopes, DOTS signal channel session mitigation scopes, DOTS signal channel session configuration data,
configuration data, and DOTS redirected signalling (Section 5). and DOTS redirected signalling (Section 5). Representing these data
Representing these data as CBOR data is assumed to follow the rules as CBOR data can either follow the rules in [I-D.ietf-core-yang-cbor]
in [I-D.ietf-core-yang-cbor] or those in [RFC7951] combined with or those in [RFC7951] combined with JSON/CBOR conversion rules in
JSON/CBOR conversion rules in [RFC7049]. All parameters in the [RFC7049]; both approaches produce a valid encoding. All parameters
payload of the DOTS signal channel are mapped to CBOR types as in the payload of the DOTS signal channel are mapped to CBOR types as
specified in Section 6. specified in Section 6.
In order to prevent fragmentation, DOTS agents must follow the In order to prevent fragmentation, DOTS agents must follow the
recommendations documented in Section 4.6 of [RFC7252]. Refer to recommendations documented in Section 4.6 of [RFC7252]. Refer to
Section 7.3 for more details. Section 7.3 for more details.
DOTS agents MUST support GET, PUT, and DELETE CoAP methods. The DOTS agents MUST support GET, PUT, and DELETE CoAP methods. The
payload included in CoAP responses with 2.xx Response Codes MUST be payload included in CoAP responses with 2.xx Response Codes MUST be
of content type "application/dots+cbor". CoAP responses with 4.xx of content type "application/dots+cbor". CoAP responses with 4.xx
and 5.xx error Response Codes MUST include a diagnostic payload and 5.xx error Response Codes MUST include a diagnostic payload
skipping to change at page 9, line 16 skipping to change at page 9, line 17
o A DOTS gateway may be co-located with the translator. The DOTS o A DOTS gateway may be co-located with the translator. The DOTS
gateway will need to update the DOTS messages, based upon the gateway will need to update the DOTS messages, based upon the
local translator's binding table. local translator's binding table.
4. DOTS Signal Channel: Messages & Behaviors 4. DOTS Signal Channel: Messages & Behaviors
4.1. DOTS Server(s) Discovery 4.1. DOTS Server(s) Discovery
This document assumes that DOTS clients are provisioned with the This document assumes that DOTS clients are provisioned with the
reachability information of their DOTS server(s) using a variety of reachability information of their DOTS server(s) using any of a
means (e.g., local configuration, or dynamic means such as DHCP). variety of means (e.g., local configuration, or dynamic means such as
The description of such means is out of scope of this document. DHCP). The description of such means is out of scope of this
document.
Likewise, it is out of scope of this document to specify the behavior Likewise, it is out of scope of this document to specify the behavior
to be followed by a DOTS client to send DOTS requests when multiple to be followed by a DOTS client to send DOTS requests when multiple
DOTS servers are provisioned (e.g., contact all DOTS servers, select DOTS servers are provisioned (e.g., contact all DOTS servers, select
one DOTS server among the list). one DOTS server among the list).
4.2. CoAP URIs 4.2. CoAP URIs
The DOTS server MUST support the use of the path-prefix of "/.well- The DOTS server MUST support the use of the path-prefix of "/.well-
known/" as defined in [RFC5785] and the registered name of "dots". known/" as defined in [RFC5785] and the registered name of "dots".
skipping to change at page 10, line 9 skipping to change at page 10, line 11
support both connectionless and connection-oriented protocols. As support both connectionless and connection-oriented protocols. As
such, the DOTS signal channel is designed to operate with DTLS over such, the DOTS signal channel is designed to operate with DTLS over
UDP and TLS over TCP. Further, a DOTS client may acquire a list of UDP and TLS over TCP. Further, a DOTS client may acquire a list of
IPv4 and IPv6 addresses (Section 4.1), each of which can be used to IPv4 and IPv6 addresses (Section 4.1), each of which can be used to
contact the DOTS server using UDP and TCP. The following specifies contact the DOTS server using UDP and TCP. The following specifies
the procedure to follow to select the address family and the the procedure to follow to select the address family and the
transport protocol for sending DOTS signal channel messages. transport protocol for sending DOTS signal channel messages.
Such procedure is needed to avoid experiencing long connection Such procedure is needed to avoid experiencing long connection
delays. For example, if an IPv4 path to reach a DOTS server is delays. For example, if an IPv4 path to reach a DOTS server is
found, but the DOTS server's IPv6 path is not working, a dual-stack functional, but the DOTS server's IPv6 path is non-functional, a
DOTS client may experience a significant connection delay compared to dual-stack DOTS client may experience a significant connection delay
an IPv4-only DOTS client. The other problem is that if a middlebox compared to an IPv4-only DOTS client, in the same network conditions.
between the DOTS client and DOTS server is configured to block UDP The other problem is that if a middlebox between the DOTS client and
traffic, the DOTS client will fail to establish a DTLS session with DOTS server is configured to block UDP traffic, the DOTS client will
the DOTS server and, as a consequence, will have to fall back to TLS fail to establish a DTLS association with the DOTS server and, as a
over TCP, thereby incurring significant connection delays. consequence, will have to fall back to TLS over TCP, thereby
incurring significant connection delays.
To overcome these connection setup problems, the DOTS client attempts To overcome these connection setup problems, the DOTS client attempts
to connect to its DOTS server(s) using both IPv6 and IPv4, and tries to connect to its DOTS server(s) using both IPv6 and IPv4, and tries
both DTLS over UDP and TLS over TCP in a manner similar to the Happy both DTLS over UDP and TLS over TCP in a manner similar to the Happy
Eyeballs mechanism [RFC8305]. These connection attempts are Eyeballs mechanism [RFC8305]. These connection attempts are
performed by the DOTS client when it initializes. The results of the performed by the DOTS client when it initializes, or in general when
Happy Eyeballs procedure are used by the DOTS client for sending its it has to select an address family and transport to contact its DOTS
subsequent messages to the DOTS server. server. The results of the Happy Eyeballs procedure are used by the
DOTS client for sending its subsequent messages to the DOTS server.
Note that the DOTS client after successfully establishing a
connection must cache information regarding the outcome of each
connection attempt for a specific time period, and it uses that
information to avoid thrashing the network with subsequent attempts.
The order of preference of the DOTS signal channel address family and The order of preference of the DOTS signal channel address family and
transport protocol (most preferred first) is: UDP over IPv6, UDP over transport protocol (most preferred first) is: UDP over IPv6, UDP over
IPv4, TCP over IPv6, and finally TCP over IPv4. This order adheres IPv4, TCP over IPv6, and finally TCP over IPv4. This order adheres
to the address preference order specified in [RFC6724] and the DOTS to the address preference order specified in [RFC6724] and the DOTS
signal channel preference which privileges the use of UDP over TCP signal channel preference which privileges the use of UDP over TCP
(to avoid TCP's head of line blocking). (to avoid TCP's head of line blocking).
In reference to Figure 4, the DOTS client sends two TCP SYNs and two In reference to Figure 4, the DOTS client sends two TCP SYNs and two
DTLS ClientHello messages at the same time over IPv6 and IPv4. In DTLS ClientHello messages at the same time over IPv6 and IPv4. In
this example, it is assumed that the IPv6 path is broken and UDP this example, it is assumed that the IPv6 path is broken and UDP
traffic is dropped by a middlebox but has little impact to the DOTS traffic is dropped by a middlebox but has little impact to the DOTS
client because there is no long delay before using IPv4 and TCP. The client because there is no long delay before using IPv4 and TCP. The
DOTS client repeats the mechanism to discover whether DOTS signal DOTS client periodically repeats the mechanism to discover whether
channel messages with DTLS over UDP becomes available from the DOTS DOTS signal channel messages with DTLS over UDP becomes available
server, so the DOTS client can migrate the DOTS signal channel from from the DOTS server, so the DOTS client can migrate the DOTS signal
TCP to UDP. Such probing SHOULD NOT be done more frequently than channel from TCP to UDP. Such probing SHOULD NOT be done more
every 24 hours and MUST NOT be done more frequently than every 5 frequently than every 24 hours and MUST NOT be done more frequently
minutes. than every 5 minutes.
A single DOTS signal channel between DOTS agents can be used to A single DOTS signal channel between DOTS agents can be used to
exchange multiple DOTS signal messages. To reduce DOTS client and exchange multiple DOTS signal messages. To reduce DOTS client and
DOTS server workload, DOTS clients SHOULD re-use the (D)TLS session. DOTS server workload, DOTS clients SHOULD re-use the (D)TLS session.
+-----------+ +-----------+ +-----------+ +-----------+
|DOTS client| |DOTS server| |DOTS client| |DOTS server|
+-----------+ +-----------+ +-----------+ +-----------+
| | | |
|--DTLS ClientHello, IPv6 ---->X | |--DTLS ClientHello, IPv6 ---->X |
skipping to change at page 11, line 22 skipping to change at page 11, line 26
|--TCP SYN, IPv4--------------------------------------->| |--TCP SYN, IPv4--------------------------------------->|
|--DTLS ClientHello, IPv6 ---->X | |--DTLS ClientHello, IPv6 ---->X |
|--TCP SYN, IPv6-------------->X | |--TCP SYN, IPv6-------------->X |
|<-TCP SYNACK-------------------------------------------| |<-TCP SYNACK-------------------------------------------|
|--DTLS ClientHello, IPv4 ---->X | |--DTLS ClientHello, IPv4 ---->X |
|--TCP ACK--------------------------------------------->| |--TCP ACK--------------------------------------------->|
|<------------Establish TLS Session-------------------->| |<------------Establish TLS Session-------------------->|
|----------------DOTS signal--------------------------->| |----------------DOTS signal--------------------------->|
| | | |
Figure 4: DOTS Happy Eyeballs Figure 4: DOTS Happy Eyeballs (Sample Flow)
4.4. DOTS Mitigation Methods 4.4. DOTS Mitigation Methods
The following methods are used by a DOTS client to request, withdraw, The following methods are used by a DOTS client to request, withdraw,
or retrieve the status of mitigation requests: or retrieve the status of mitigation requests:
PUT: DOTS clients use the PUT method to request mitigation from a PUT: DOTS clients use the PUT method to request mitigation from a
DOTS server (Section 4.4.1). During active mitigation, DOTS DOTS server (Section 4.4.1). During active mitigation, DOTS
clients may use PUT requests to carry mitigation efficacy clients may use PUT requests to carry mitigation efficacy
updates to the DOTS server (Section 4.4.3). updates to the DOTS server (Section 4.4.3).
skipping to change at page 12, line 8 skipping to change at page 12, line 13
the peer DOTS agent on average. the peer DOTS agent on average.
Requests marked by the DOTS client as Non-confirmable messages are Requests marked by the DOTS client as Non-confirmable messages are
sent at regular intervals until a response is received from the DOTS sent at regular intervals until a response is received from the DOTS
server. If the DOTS client cannot maintain an RTT estimate, it server. If the DOTS client cannot maintain an RTT estimate, it
SHOULD NOT send more than one Non-confirmable request every 3 SHOULD NOT send more than one Non-confirmable request every 3
seconds, and SHOULD use an even less aggressive rate whenever seconds, and SHOULD use an even less aggressive rate whenever
possible (case 2 in Section 3.1.3 of [RFC8085]). possible (case 2 in Section 3.1.3 of [RFC8085]).
JSON diagnostic notation is used to illustrate the various methods JSON diagnostic notation is used to illustrate the various methods
defined in the following sub-sections. defined in the following sub-sections. Also, the examples use the
Labels defined in Sections 9.6.2, 9.6.3, 9.6.4, and 9.6.5.
4.4.1. Request Mitigation 4.4.1. Request Mitigation
When a DOTS client requires mitigation for some reason, the DOTS When a DOTS client requires mitigation for some reason, the DOTS
client uses the CoAP PUT method to send a mitigation request to its client uses the CoAP PUT method to send a mitigation request to its
DOTS server(s) (Figure 5). DOTS server(s) (Figures 5 and 6).
If a DOTS client is entitled to solicit the DOTS service, the DOTS If a DOTS client is entitled to solicit the DOTS service, the DOTS
server can enable mitigation on behalf of the DOTS client by server enables mitigation on behalf of the DOTS client by
communicating the DOTS client's request to a mitigator and relaying communicating the DOTS client's request to a mitigator (which may be
the feedback of the thus-selected mitigator to the requesting DOTS colocated with the DOTS server) and relaying the feedback of the
client. thus-selected mitigator to the requesting DOTS client.
Header: PUT (Code=0.03) Header: PUT (Code=0.03)
Uri-Path: ".well-known" Uri-Path: ".well-known"
Uri-Path: "dots" Uri-Path: "dots"
Uri-Path: "mitigate" Uri-Path: "mitigate"
Uri-Path: "cuid=dz6pHjaADkaFTbjr0JGBpw" Uri-Path: "cuid=dz6pHjaADkaFTbjr0JGBpw"
Uri-Path: "mid=123" Uri-Path: "mid=123"
Content-Type: "application/dots+cbor" Content-Format: "application/dots+cbor"
{ {
"ietf-dots-signal-channel:mitigation-scope": { ...
"scope": [
{
"target-prefix": [
"string"
],
"target-port-range": [
{
"lower-port": number,
"upper-port": number
}
],
"target-protocol": [
number
],
"target-fqdn": [
"string"
],
"target-uri": [
"string"
],
"alias-name": [
"string"
],
"lifetime": number,
"trigger-mitigation": true|false
}
]
}
} }
Figure 5: PUT to Convey DOTS Mitigation Requests Figure 5: PUT to Convey DOTS Mitigation Requests
The order of the Uri-Path options is important as it defines the CoAP The order of the Uri-Path options is important as it defines the CoAP
resource. In particular, 'mid' MUST follow 'cuid'. resource. In particular, 'mid' MUST follow 'cuid'.
The additional Uri-Path parameters to those defined in Section 4.2 The additional Uri-Path parameters to those defined in Section 4.2
are as follows: are as follows:
cuid: Stands for Client Unique Identifier. A globally unique cuid: Stands for Client Unique Identifier. A globally unique
identifier that is meant to prevent collisions among DOTS clients, identifier that is meant to prevent collisions among DOTS clients,
especially those from the same domain. It MUST be generated by especially those from the same domain. It MUST be generated by
DOTS clients. DOTS clients.
Implementations SHOULD use the output of a cryptographic hash Implementations SHOULD set 'cuid' to the output of a cryptographic
algorithm whose input is the Distinguished Encoding Rules (DER)- hash algorithm whose input is the Distinguished Encoding Rules
encoded Abstract Syntax Notation One (ASN.1) representation of the (DER)-encoded Abstract Syntax Notation One (ASN.1) representation
Subject Public Key Info (SPKI) of the DOTS client X.509 of the Subject Public Key Info (SPKI) of the DOTS client X.509
certificate [RFC5280], the DOTS client raw public key [RFC7250], certificate [RFC5280], the DOTS client raw public key [RFC7250],
or the "Pre-Shared Key (PSK) identity" used by the DOTS client in or the "Pre-Shared Key (PSK) identity" used by the DOTS client in
the TLS ClientKeyExchange message to set 'cuid'. In this version the TLS ClientKeyExchange message. In this version of the
of the specification, the cryptographic hash algorithm used is specification, the recommended cryptographic hash algorithm is
SHA-256 [RFC6234]. The output of the cryptographic hash algorithm SHA-256 [RFC6234]. The output of the cryptographic hash algorithm
is truncated to 16 bytes; truncation is done by stripping off the is truncated to 16 bytes; truncation is done by stripping off the
final 16 bytes. The truncated output is base64url encoded. final 16 bytes. The truncated output is base64url encoded.
The 'cuid' is intended to be stable when communicating with a The 'cuid' is intended to be stable when communicating with a
given DOTS server, i.e., the 'cuid' used by a DOTS client SHOULD given DOTS server, i.e., the 'cuid' used by a DOTS client SHOULD
NOT change over time. Distinct 'cuid' values MAY be used per DOTS NOT change over time. Distinct 'cuid' values MAY be used by a
server. single DOTS client per DOTS server.
DOTS servers MUST return 4.09 (Conflict) error code to a DOTS peer DOTS servers MUST return 4.09 (Conflict) error code to a DOTS peer
to notify that the 'cuid' is already in-use by another DOTS to notify that the 'cuid' is already in-use by another DOTS
client. Upon receipt of that error code, a new 'cuid' MUST be client. Upon receipt of that error code, a new 'cuid' MUST be
generated by the DOTS peer. generated by the DOTS peer (e.g., using [RFC4122]).
Client-domain DOTS gateways MUST handle 'cuid' collision directly Client-domain DOTS gateways MUST handle 'cuid' collision directly
and it is RECOMMENDED that 'cuid' collision is handled directly by and it is RECOMMENDED that 'cuid' collision is handled directly by
server-domain DOTS gateways. server-domain DOTS gateways.
DOTS gateways MAY rewrite the 'cuid' used by peer DOTS clients. DOTS gateways MAY rewrite the 'cuid' used by peer DOTS clients.
Triggers for such rewriting are out of scope. Triggers for such rewriting are out of scope.
This is a mandatory Uri-Path parameter. This is a mandatory Uri-Path parameter.
mid: Identifier for the mitigation request represented with an mid: Identifier for the mitigation request represented with an
integer. This identifier MUST be unique for each mitigation integer. This identifier MUST be unique for each mitigation
request bound to the DOTS client, i.e., the 'mid' parameter value request bound to the DOTS client, i.e., the 'mid' parameter value
in the mitigation request needs to be unique relative to the 'mid' in the mitigation request needs to be unique (per 'cuid' and DOTS
parameter values of active mitigation requests conveyed from the server) relative to the 'mid' parameter values of active
DOTS client to the DOTS server. mitigation requests conveyed from the DOTS client to the DOTS
server.
In order to handle out-of-order delivery of mitigation requests, In order to handle out-of-order delivery of mitigation requests,
'mid' values MUST increase monotonically. 'mid' values MUST increase monotonically.
If the 'mid' value has reached 3/4 of (2**32 - 1) (i.e., If the 'mid' value has reached 3/4 of (2**32 - 1) (i.e.,
3221225471) and it is peace-time, the DOTS client MUST reset 'mid' 3221225471) and no attack is detected, the DOTS client MUST reset
to 0 to handle 'mid' rollover. If the DOTS client maintains 'mid' to 0 to handle 'mid' rollover. If the DOTS client maintains
mitigation requests with pre-configured scopes, it MUST re-create mitigation requests with pre-configured scopes, it MUST re-create
them with the 'mid' restarting at 0. them with the 'mid' restarting at 0.
This identifier MUST be generated by the DOTS client. This identifier MUST be generated by the DOTS client.
This is a mandatory Uri-Path parameter. This is a mandatory Uri-Path parameter.
'cuid' and 'mid' MUST NOT appear in the PUT request message body. 'cuid' and 'mid' MUST NOT appear in the PUT request message body
(Figure 6).
The parameters in the CBOR body of the PUT request are described Content-Format: "application/dots+cbor"
below: {
"ietf-dots-signal-channel:mitigation-scope": {
"scope": [
{
"target-prefix": [
"string"
],
"target-port-range": [
{
"lower-port": number,
"upper-port": number
}
],
"target-protocol": [
number
],
"target-fqdn": [
"string"
],
"target-uri": [
"string"
],
"alias-name": [
"string"
],
"lifetime": number,
"trigger-mitigation": true|false
}
]
}
}
Figure 6: PUT to Convey DOTS Mitigation Requests (Message Body
Schema)
The parameters in the CBOR body (Figure 6) of the PUT request are
described below:
target-prefix: A list of prefixes identifying resources under target-prefix: A list of prefixes identifying resources under
attack. Prefixes are represented using Classless Inter-Domain attack. Prefixes are represented using Classless Inter-Domain
Routing (CIDR) notation [RFC4632]. Routing (CIDR) notation [RFC4632].
As a reminder, the prefix length must be less than or equal to 32 As a reminder, the prefix length must be less than or equal to 32
(resp. 128) for IPv4 (resp. IPv6). (resp. 128) for IPv4 (resp. IPv6).
The prefix list MUST NOT include broadcast, loopback, or multicast The prefix list MUST NOT include broadcast, loopback, or multicast
addresses. These addresses are considered as invalid values. In addresses. These addresses are considered as invalid values. In
addition, the DOTS server MUST validate that target prefixes are addition, the DOTS server MUST validate that target prefixes are
skipping to change at page 15, line 48 skipping to change at page 15, line 36
For TCP, UDP, Stream Control Transmission Protocol (SCTP) For TCP, UDP, Stream Control Transmission Protocol (SCTP)
[RFC4960], or Datagram Congestion Control Protocol (DCCP) [RFC4960], or Datagram Congestion Control Protocol (DCCP)
[RFC4340], a range of ports can be, for example, 0-1023, [RFC4340], a range of ports can be, for example, 0-1023,
1024-65535, or 1024-49151. 1024-65535, or 1024-49151.
This is an optional attribute. This is an optional attribute.
target-protocol: A list of protocols involved in an attack. Values target-protocol: A list of protocols involved in an attack. Values
are taken from the IANA protocol registry [proto_numbers]. are taken from the IANA protocol registry [proto_numbers].
The value '0' has a special meaning for 'all protocols'. If 'target-protocol' is not specified, then the request applies to
any protocol.
This is an optional attribute. This is an optional attribute.
target-fqdn: A list of Fully Qualified Domain Names (FQDNs) target-fqdn: A list of Fully Qualified Domain Names (FQDNs)
identifying resources under attack. An FQDN is the full name of a identifying resources under attack [RFC8499].
resource, rather than just its hostname. For example, "venera" is
a hostname, and "venera.isi.edu" is an FQDN [RFC1983].
How a name is passed to an underlying name resolution library is How a name is passed to an underlying name resolution library is
implementation- and deployment-specific. Nevertheless, once the implementation- and deployment-specific. Nevertheless, once the
name is resolved into one or multiple IP addresses, DOTS servers name is resolved into one or multiple IP addresses, DOTS servers
MUST apply the same validation checks as those for 'target- MUST apply the same validation checks as those for 'target-
prefix'. prefix'.
The use of FQDNs may be suboptimal because:
* It induces both an extra load and increased delays on the DOTS
server to handle and manage DNS resolution requests.
* It does not guarantee that the DOTS server will resolve a name
to the same IP addresses that the DOTS client does.
This is an optional attribute. This is an optional attribute.
target-uri: A list of Uniform Resource Identifiers (URIs) [RFC3986] target-uri: A list of Uniform Resource Identifiers (URIs) [RFC3986]
identifying resources under attack. identifying resources under attack.
The same validation checks used for 'target-fqdn' MUST be followed The same validation checks used for 'target-fqdn' MUST be followed
by DOTS servers to validate a target URI. by DOTS servers to validate a target URI.
This is an optional attribute. This is an optional attribute.
skipping to change at page 16, line 39 skipping to change at page 16, line 34
configuration, or other means. configuration, or other means.
An alias is used in subsequent signal channel exchanges to refer An alias is used in subsequent signal channel exchanges to refer
more efficiently to the resources under attack. more efficiently to the resources under attack.
This is an optional attribute. This is an optional attribute.
lifetime: Lifetime of the mitigation request in seconds. The lifetime: Lifetime of the mitigation request in seconds. The
RECOMMENDED lifetime of a mitigation request is 3600 seconds -- RECOMMENDED lifetime of a mitigation request is 3600 seconds --
this value was chosen to be long enough so that refreshing is not this value was chosen to be long enough so that refreshing is not
typically a burden on the DOTS client, while expiring the request typically a burden on the DOTS client, while still making the
where the client has unexpectedly quit in a timely manner. DOTS request expire in a timely manner when the client has unexpectedly
clients MUST include this parameter in their mitigation requests. quit. DOTS clients MUST include this parameter in their
Upon the expiry of this lifetime, and if the request is not mitigation requests. Upon the expiry of this lifetime, and if the
refreshed, the mitigation request is removed. The request can be request is not refreshed, the mitigation request is removed. The
refreshed by sending the same request again. request can be refreshed by sending the same request again.
A lifetime of '0' in a mitigation request is an invalid value. A lifetime of '0' in a mitigation request is an invalid value.
A lifetime of negative one (-1) indicates indefinite lifetime for A lifetime of negative one (-1) indicates indefinite lifetime for
the mitigation request. The DOTS server MAY refuse indefinite the mitigation request. The DOTS server MAY refuse indefinite
lifetime, for policy reasons; the granted lifetime value is lifetime, for policy reasons; the granted lifetime value is
returned in the response. DOTS clients MUST be prepared to not be returned in the response. DOTS clients MUST be prepared to not be
granted mitigations with indefinite lifetimes. granted mitigations with indefinite lifetimes.
The DOTS server MUST always indicate the actual lifetime in the The DOTS server MUST always indicate the actual lifetime in the
skipping to change at page 17, line 28 skipping to change at page 17, line 24
The default value of the parameter is 'true' (that is, the The default value of the parameter is 'true' (that is, the
mitigation starts immediately). If 'trigger-mitigation' is not mitigation starts immediately). If 'trigger-mitigation' is not
present in a request, this is equivalent to receiving a request present in a request, this is equivalent to receiving a request
with 'trigger-mitigation' set to 'true'. with 'trigger-mitigation' set to 'true'.
This is an optional attribute. This is an optional attribute.
In deployments where server-domain DOTS gateways are enabled, In deployments where server-domain DOTS gateways are enabled,
identity information about the origin source client domain SHOULD be identity information about the origin source client domain SHOULD be
supplied to the DOTS server. That information is meant to assist the propagated to the DOTS server. That information is meant to assist
DOTS server to enforce some policies such as correlating DOTS clients the DOTS server to enforce some policies such as grouping DOTS
that belong to the same DOTS domain, limiting the number of DOTS clients that belong to the same DOTS domain, limiting the number of
requests, and identifying the mitigation scope. These policies can DOTS requests, and identifying the mitigation scope. These policies
be enforced per-client, per-client domain, or both. Also, the can be enforced per-client, per-client domain, or both. Also, the
identity information may be used for auditing and debugging purposes. identity information may be used for auditing and debugging purposes.
Figure 6 shows an example of a request relayed by a server-domain Figure 7 shows an example of a request relayed by a server-domain
DOTS gateway. DOTS gateway.
Header: PUT (Code=0.03) Header: PUT (Code=0.03)
Uri-Path: ".well-known" Uri-Path: ".well-known"
Uri-Path: "dots" Uri-Path: "dots"
Uri-Path: "mitigate" Uri-Path: "mitigate"
Uri-Path: "cdid=7eeaf349529eb55ed50113" Uri-Path: "cdid=7eeaf349529eb55ed50113"
Uri-Path: "cuid=dz6pHjaADkaFTbjr0JGBpw" Uri-Path: "cuid=dz6pHjaADkaFTbjr0JGBpw"
Uri-Path: "mid=123" Uri-Path: "mid=123"
Content-Type: "application/dots+cbor" Content-Format: "application/dots+cbor"
{ {
"ietf-dots-signal-channel:mitigation-scope": { ...
"scope": [
{
"target-prefix": [
"string"
],
"target-port-range": [
{
"lower-port": number,
"upper-port": number
}
],
"target-protocol": [
number
],
"target-fqdn": [
"string"
],
"target-uri": [
"string"
],
"alias-name": [
"string"
],
"lifetime": number
}
]
}
} }
Figure 6: PUT to Convey DOTS Mitigation Request as relayed by a Figure 7: PUT for DOTS Mitigation Request as Relayed by a DOTS
Server-Domain DOTS Gateway Gateway
A server-domain DOTS gateway SHOULD add the following Uri-Path A server-domain DOTS gateway SHOULD add the following Uri-Path
parameter: parameter:
cdid: Stands for Client Domain Identifier. The 'cdid' is conveyed cdid: Stands for Client Domain Identifier. The 'cdid' is conveyed
by a server-domain DOTS gateway to propagate the source domain by a server-domain DOTS gateway to propagate the source domain
identity from the gateway's client-facing-side to the gateway's identity from the gateway's client-facing-side to the gateway's
server-facing-side, and from the gateway's server-facing-side to server-facing-side, and from the gateway's server-facing-side to
the DOTS server. 'cdid' may be used by the final DOTS server for the DOTS server. 'cdid' may be used by the final DOTS server for
policy enforcement purposes (e.g., enforce a quota on filtering policy enforcement purposes (e.g., enforce a quota on filtering
rules). These policies are deployment-specific. rules). These policies are deployment-specific.
Server-domain DOTS gateways SHOULD support a configuration option Server-domain DOTS gateways SHOULD support a configuration option
to instruct whether 'cdid' parameter is to be inserted. to instruct whether 'cdid' parameter is to be inserted.
In order to accommodate deployments that require enforcing per- In order to accommodate deployments that require enforcing per-
client policies, per-client domain policies, or a combination client policies, per-client domain policies, or a combination
thereof, server-domain DOTS gateways MUST supply the SPKI hash of thereof, server-domain DOTS gateways instructed to insert the
the DOTS client X.509 certificate, the DOTS client raw public key, 'cdid' parameter MUST supply the SPKI hash of the DOTS client
or the hash of the "PSK identity" in the 'cdid', following the X.509 certificate, the DOTS client raw public key, or the hash of
same rules for generating the hash conveyed in 'cuid', which is the "PSK identity" in the 'cdid', following the same rules for
then used by the ultimate DOTS server to determine the generating the hash conveyed in 'cuid', which is then used by the
corresponding client's domain. The 'cdid' generated by a server- ultimate DOTS server to determine the corresponding client's
domain gateway is likely to be the same as the 'cuid' except if domain. The 'cdid' generated by a server-domain gateway is likely
the DOTS message was relayed by a DOTS gateway or was generated to be the same as the 'cuid' except if the DOTS message was
from a rogue DOTS client. relayed by a client-domain DOTS gateway or the 'cuid' was
generated from a rogue DOTS client.
If a DOTS client is provisioned, for example, with distinct If a DOTS client is provisioned, for example, with distinct
certificates as a function of the peer server-domain DOTS gateway, certificates as a function of the peer server-domain DOTS gateway,
distinct 'cdid' values may be supplied by a server-domain DOTS distinct 'cdid' values may be supplied by a server-domain DOTS
gateway. The ultimate DOTS server MUST treat those 'cdid' values gateway. The ultimate DOTS server MUST treat those 'cdid' values
as equivalent. as equivalent.
The 'cdid' attribute MUST NOT be generated and included by DOTS The 'cdid' attribute MUST NOT be generated and included by DOTS
clients. clients.
skipping to change at page 19, line 51 skipping to change at page 19, line 8
This is an optional Uri-Path. When present, 'cdid' MUST be This is an optional Uri-Path. When present, 'cdid' MUST be
positioned before 'cuid'. positioned before 'cuid'.
A DOTS gateway MAY add the CoAP Hop-Limit Option A DOTS gateway MAY add the CoAP Hop-Limit Option
[I-D.ietf-core-hop-limit]. [I-D.ietf-core-hop-limit].
Because of the complexity to handle partial failure cases, this Because of the complexity to handle partial failure cases, this
specification does not allow for including multiple mitigation specification does not allow for including multiple mitigation
requests in the same PUT request. Concretely, a DOTS client MUST NOT requests in the same PUT request. Concretely, a DOTS client MUST NOT
include multiple 'scope' parameters in the same PUT request. include multiple entries in the 'scope' array of the same PUT
request.
FQDN and URI mitigation scopes may be thought of as a form of scope FQDN and URI mitigation scopes may be thought of as a form of scope
alias, in which the addresses associated with the domain name or URI alias, in which the addresses associated with the domain name or URI
represent the full scope of the mitigation. (as resolved by the DOTS server) represent the full scope of the
mitigation.
In the PUT request at least one of the attributes 'target-prefix', In the PUT request at least one of the attributes 'target-prefix',
'target-fqdn','target-uri', or 'alias-name' MUST be present. 'target-fqdn','target-uri', or 'alias-name' MUST be present.
Attributes and Uri-Path parameters with empty values MUST NOT be Attributes and Uri-Path parameters with empty values MUST NOT be
present in a request. present in a request and render the entire request invalid.
Figure 7 shows a PUT request example to signal that ports 80, 8080, Figure 8 shows a PUT request example to signal that TCP port numbers
and 443 used by 2001:db8:6401::1 and 2001:db8:6401::2 servers are 80, 8080, and 443 used by 2001:db8:6401::1 and 2001:db8:6401::2
under attack (illustrated in JSON diagnostic notation). The presence servers are under attack (illustrated in JSON diagnostic notation).
of 'cdid' indicates that a server-domain DOTS gateway has modified The presence of 'cdid' indicates that a server-domain DOTS gateway
the initial PUT request sent by the DOTS client. Note that 'cdid' has modified the initial PUT request sent by the DOTS client. Note
MUST NOT appear in the PUT request message body. that 'cdid' MUST NOT appear in the PUT request message body.
Header: PUT (Code=0.03) Header: PUT (Code=0.03)
Uri-Path: ".well-known" Uri-Path: ".well-known"
Uri-Path: "dots" Uri-Path: "dots"
Uri-Path: "mitigate" Uri-Path: "mitigate"
Uri-Path: "cdid=7eeaf349529eb55ed50113" Uri-Path: "cdid=7eeaf349529eb55ed50113"
Uri-Path: "cuid=dz6pHjaADkaFTbjr0JGBpw" Uri-Path: "cuid=dz6pHjaADkaFTbjr0JGBpw"
Uri-Path: "mid=123" Uri-Path: "mid=123"
Content-Format: "application/dots+cbor" Content-Format: "application/dots+cbor"
{ {
skipping to change at page 21, line 41 skipping to change at page 20, line 41
], ],
"target-protocol": [ "target-protocol": [
6 6
], ],
"lifetime": 3600 "lifetime": 3600
} }
] ]
} }
} }
Figure 7: PUT for DOTS Mitigation Request Figure 8: PUT for DOTS Mitigation Request (An Example)
The corresponding CBOR encoding format is shown in Figure 8. The corresponding CBOR encoding format for the payload is shown in
Figure 9.
A1 # map(1) A1 # map(1)
01 # unsigned(1) 01 # unsigned(1)
A1 # map(1) A1 # map(1)
02 # unsigned(2) 02 # unsigned(2)
81 # array(1) 81 # array(1)
A3 # map(3) A3 # map(3)
06 # unsigned(6) 06 # unsigned(6)
82 # array(2) 82 # array(2)
74 # text(20) 74 # text(20)
skipping to change at page 22, line 34 skipping to change at page 21, line 34
19 01BB # unsigned(443) 19 01BB # unsigned(443)
A1 # map(1) A1 # map(1)
08 # unsigned(8) 08 # unsigned(8)
19 1F90 # unsigned(8080) 19 1F90 # unsigned(8080)
0A # unsigned(10) 0A # unsigned(10)
81 # array(1) 81 # array(1)
06 # unsigned(6) 06 # unsigned(6)
0E # unsigned(14) 0E # unsigned(14)
19 0E10 # unsigned(3600) 19 0E10 # unsigned(3600)
Figure 8: PUT for DOTS Mitigation Request (CBOR) Figure 9: PUT for DOTS Mitigation Request (CBOR)
In both DOTS signal and data channel sessions, the DOTS client MUST In both DOTS signal and data channel sessions, the DOTS client MUST
authenticate itself to the DOTS server (Section 8). The DOTS server authenticate itself to the DOTS server (Section 8). The DOTS server
MAY use the algorithm presented in Section 7 of [RFC7589] to derive MAY use the algorithm presented in Section 7 of [RFC7589] to derive
the DOTS client identity or username from the client certificate. the DOTS client identity or username from the client certificate.
The DOTS client identity allows the DOTS server to accept mitigation The DOTS client identity allows the DOTS server to accept mitigation
requests with scopes that the DOTS client is authorized to manage. requests with scopes that the DOTS client is authorized to manage.
The DOTS server couples the DOTS signal and data channel sessions The DOTS server couples the DOTS signal and data channel sessions
using the DOTS client identity and optionally the 'cdid' parameter using the DOTS client identity and optionally the 'cdid' parameter
skipping to change at page 23, line 15 skipping to change at page 22, line 15
detect duplicate mitigation requests. If the mitigation request detect duplicate mitigation requests. If the mitigation request
contains the 'alias-name' and other parameters identifying the target contains the 'alias-name' and other parameters identifying the target
resources (such as 'target-prefix', 'target-port-range', 'target- resources (such as 'target-prefix', 'target-port-range', 'target-
fqdn', or 'target-uri'), the DOTS server appends the parameter values fqdn', or 'target-uri'), the DOTS server appends the parameter values
in 'alias-name' with the corresponding parameter values in 'target- in 'alias-name' with the corresponding parameter values in 'target-
prefix', 'target-port-range', 'target-fqdn', or 'target-uri'. prefix', 'target-port-range', 'target-fqdn', or 'target-uri'.
The DOTS server indicates the result of processing the PUT request The DOTS server indicates the result of processing the PUT request
using CoAP response codes. CoAP 2.xx codes are success. CoAP 4.xx using CoAP response codes. CoAP 2.xx codes are success. CoAP 4.xx
codes are some sort of invalid requests (client errors). COAP 5.xx codes are some sort of invalid requests (client errors). COAP 5.xx
codes are returned if the DOTS server has erred or is currently codes are returned if the DOTS server is in an error state or is
unavailable to provide mitigation in response to the mitigation currently unavailable to provide mitigation in response to the
request from the DOTS client. mitigation request from the DOTS client.
Figure 9 shows an example response to a PUT request that is Figure 10 shows an example response to a PUT request that is
successfully processed by a DOTS server (i.e., CoAP 2.xx response successfully processed by a DOTS server (i.e., CoAP 2.xx response
codes). This version of the specification forbids 'cuid' and 'cdid' codes). This version of the specification forbids 'cuid' and 'cdid'
(if used) to be returned in a response message body. (if used) to be returned in a response message body.
{ {
"ietf-dots-signal-channel:mitigation-scope": { "ietf-dots-signal-channel:mitigation-scope": {
"scope": [ "scope": [
{ {
"mid": 123, "mid": 123,
"lifetime": 3600 "lifetime": 3600
} }
] ]
} }
} }
Figure 9: 2.xx Response Body Figure 10: 2.xx Response Body
If the request is missing a mandatory attribute, does not include If the request is missing a mandatory attribute, does not include
'cuid' or 'mid' Uri-Path options, includes multiple 'scope' 'cuid' or 'mid' Uri-Path options, includes multiple 'scope'
parameters, or contains invalid or unknown parameters, the DOTS parameters, or contains invalid or unknown parameters, the DOTS
server MUST reply with 4.00 (Bad Request). DOTS agents can safely server MUST reply with 4.00 (Bad Request). DOTS agents can safely
ignore Vendor-Specific parameters they don't understand. ignore comprehension-optional parameters they don't understand.
A DOTS server that receives a mitigation request with a lifetime set A DOTS server that receives a mitigation request with a lifetime set
to '0' MUST reply with a 4.00 (Bad Request). to '0' MUST reply with a 4.00 (Bad Request).
If the DOTS server does not find the 'mid' parameter value conveyed If the DOTS server does not find the 'mid' parameter value conveyed
in the PUT request in its configuration data, it MAY accept the in the PUT request in its configuration data, it MAY accept the
mitigation request by sending back a 2.01 (Created) response to the mitigation request by sending back a 2.01 (Created) response to the
DOTS client; the DOTS server will consequently try to mitigate the DOTS client; the DOTS server will consequently try to mitigate the
attack. attack. A DOTS server could reject mitigation requests when it is
near capacity or needs to rate-limit a particular client, for
example.
If the DOTS server finds the 'mid' parameter value conveyed in the If the DOTS server finds the 'mid' parameter value conveyed in the
PUT request in its configuration data bound to that DOTS client, it PUT request in its configuration data bound to that DOTS client, it
MAY update the mitigation request, and a 2.04 (Changed) response is MAY update the mitigation request, and a 2.04 (Changed) response is
returned to indicate a successful update of the mitigation request. returned to indicate a successful update of the mitigation request.
The relative order of two mitigation requests, having the same The relative order of two mitigation requests, having the same
'trigger-mitigation' type, from a DOTS client is determined by 'trigger-mitigation' type, from a DOTS client is determined by
comparing their respective 'mid' values. If two mitigation requests comparing their respective 'mid' values. If two mitigation requests
with the same 'trigger-mitigation' type have overlapping mitigation with the same 'trigger-mitigation' type have overlapping mitigation
skipping to change at page 24, line 27 skipping to change at page 23, line 29
address, IP prefix, FQDN, URI, or alias-name. To avoid maintaining a address, IP prefix, FQDN, URI, or alias-name. To avoid maintaining a
long list of overlapping mitigation requests (i.e., requests with the long list of overlapping mitigation requests (i.e., requests with the
same 'trigger-mitigation' type and overlapping scopes) from a DOTS same 'trigger-mitigation' type and overlapping scopes) from a DOTS
client and avoid error-prone provisioning of mitigation requests from client and avoid error-prone provisioning of mitigation requests from
a DOTS client, the overlapped lower numeric 'mid' MUST be a DOTS client, the overlapped lower numeric 'mid' MUST be
automatically deleted and no longer available at the DOTS server. automatically deleted and no longer available at the DOTS server.
For example, if the DOTS server receives a mitigation request which For example, if the DOTS server receives a mitigation request which
overlaps with an existing mitigation with a higher numeric 'mid', the overlaps with an existing mitigation with a higher numeric 'mid', the
DOTS server rejects the request by returning 4.09 (Conflict) to the DOTS server rejects the request by returning 4.09 (Conflict) to the
DOTS client. The response includes enough information for a DOTS DOTS client. The response includes enough information for a DOTS
client to recognize the source of the conflict as described below: client to recognize the source of the conflict as described below in
the 'conflict-information' subtree with only the relevant nodes
listed:
conflict-information: Indicates that a mitigation request is conflict-information: Indicates that a mitigation request is
conflicting with another mitigation request. This optional conflicting with another mitigation request. This optional
attribute has the following structure: attribute has the following structure:
conflict-cause: Indicates the cause of the conflict. The conflict-cause: Indicates the cause of the conflict. The
following values are defined: following values are defined:
1: Overlapping targets. 'conflict-scope' provides more details 1: Overlapping targets. 'conflict-scope' provides more details
about the conflicting target clauses. about the conflicting target clauses.
conflict-scope: Indicates the conflict scope. It may include a conflict-scope: Characterizes the exact conflict scope. It may
list of IP addresses, a list of prefixes, a list of port include a list of IP addresses, a list of prefixes, a list of
numbers, a list of target protocols, a list of FQDNs, a list of port numbers, a list of target protocols, a list of FQDNs, a
URIs, a list of alias-names, or a 'mid'. list of URIs, a list of alias-names, or a 'mid'.
If the DOTS server receives a mitigation request which overlaps with If the DOTS server receives a mitigation request which overlaps with
an active mitigation request, but both having distinct 'trigger- an active mitigation request, but both having distinct 'trigger-
mitigation' types, the DOTS server MUST deactivate (absent explicit mitigation' types, the DOTS server MUST deactivate (absent explicit
policy/configuration otherwise) the mitigation request with 'trigger- policy/configuration otherwise) the mitigation request with 'trigger-
mitigation' set to false. Particularly, if the mitigation request mitigation' set to false. Particularly, if the mitigation request
with 'trigger-mitigation' set to false is active, the DOTS server with 'trigger-mitigation' set to false is active, the DOTS server
withdraws the mitigation request (i.e., status code is set to '7' as withdraws the mitigation request (i.e., status code is set to '7' as
defined in Table 2) and transitions the status of the mitigation defined in Table 2) and transitions the status of the mitigation
request to '8'. request to '8'.
Upon DOTS signal channel session loss with a peer DOTS client, the Upon DOTS signal channel session loss with a peer DOTS client, the
DOTS server MUST withdraw (absent explicit policy/configuration DOTS server MUST withdraw (absent explicit policy/configuration
otherwise) any active mitigation requests overlapping with mitigation otherwise) any active mitigation requests overlapping with mitigation
requests having 'trigger-mitigation' set to false from that DOTS requests having 'trigger-mitigation' set to false from that DOTS
client. Note that active-but-terminating period is not observed for client, as the loss of the session implictily activates these
mitigations withdrawn at the initiative of the DOTS server. preconfigured mitigation requests and they take precedence. Note
that active-but-terminating period is not observed for mitigations
withdrawn at the initiative of the DOTS server.
DOTS clients may adopt various strategies for setting the scopes of DOTS clients may adopt various strategies for setting the scopes of
immediate and pre-configured mitigation requests to avoid potential immediate and pre-configured mitigation requests to avoid potential
conflicts. For example, a DOTS client may tweak pre-configured conflicts. For example, a DOTS client may tweak pre-configured
scopes so that the scope of any overlapping immediate mitigation scopes so that the scope of any overlapping immediate mitigation
request will be a subset of the pre-configured scopes. Also, if an request will be a subset of the pre-configured scopes. Also, if an
immediate mitigation request overlaps with any of the pre-configured immediate mitigation request overlaps with any of the pre-configured
scopes, the DOTS client sets the scope of the overlapping immediate scopes, the DOTS client sets the scope of the overlapping immediate
mitigation request to be a subset of the pre-configured scopes. mitigation request to be a subset of the pre-configured scopes, so as
to get a broad mitigation when the DOTS signal channel collapses and
maximize the chance of recovery.
If the request is conflicting with an existing mitigation request If the request is conflicting with an existing mitigation request
from a different DOTS client, the DOTS server may return 2.01 from a different DOTS client, the DOTS server may return 2.01
(Created) or 4.09 (Conflict) to the requesting DOTS client. If the (Created) or 4.09 (Conflict) to the requesting DOTS client. If the
DOTS server decides to maintain the new mitigation request, the DOTS DOTS server decides to maintain the new mitigation request, the DOTS
server returns 2.01 (Created) to the requesting DOTS client. If the server returns 2.01 (Created) to the requesting DOTS client. If the
DOTS server decides to reject the new mitigation request, the DOTS DOTS server decides to reject the new mitigation request, the DOTS
server returns 4.09 (Conflict) to the requesting DOTS client. For server returns 4.09 (Conflict) to the requesting DOTS client. For
both 2.01 (Created) and 4.09 (Conflict) responses, the response both 2.01 (Created) and 4.09 (Conflict) responses, the response
includes enough information for a DOTS client to recognize the source includes enough information for a DOTS client to recognize the source
skipping to change at page 26, line 21 skipping to change at page 25, line 29
2: Conflicts with an existing accept-list. This code is 2: Conflicts with an existing accept-list. This code is
returned when the DDoS mitigation detects source addresses/ returned when the DDoS mitigation detects source addresses/
prefixes in the accept-listed ACLs are attacking the prefixes in the accept-listed ACLs are attacking the
target. target.
3: CUID Collision. This code is returned when a DOTS client 3: CUID Collision. This code is returned when a DOTS client
uses a 'cuid' that is already used by another DOTS client. uses a 'cuid' that is already used by another DOTS client.
This code is an indication that the request has been This code is an indication that the request has been
rejected and a new request with a new 'cuid' is to be re- rejected and a new request with a new 'cuid' is to be re-
sent by the DOTS client. Note that 'conflict-status', sent by the DOTS client. Note that 'conflict-status',
'conflict-scope', and 'retry-timer' are not returned in the 'conflict-scope', and 'retry-timer' MUST NOT be returned in
error response. the error response.
conflict-scope: Indicates the conflict scope. It may include a conflict-scope: Characterizes the exact conflict scope. It may
list of IP addresses, a list of prefixes, a list of port include a list of IP addresses, a list of prefixes, a list of
numbers, a list of target protocols, a list of FQDNs, a list of port numbers, a list of target protocols, a list of FQDNs, a
URIs, a list of alias-names, or references to conflicting ACLs. list of URIs, a list of alias-names, or references to
conflicting ACLs (by an 'acl-name', typically
[I-D.ietf-dots-data-channel]).
retry-timer: Indicates, in seconds, the time after which the DOTS retry-timer: Indicates, in seconds, the time after which the DOTS
client may re-issue the same request. The DOTS server returns client may re-issue the same request. The DOTS server returns
'retry-timer' only to DOTS client(s) for which a mitigation 'retry-timer' only to DOTS client(s) for which a mitigation
request is deactivated. Any retransmission of the same request is deactivated. Any retransmission of the same
mitigation request before the expiry of this timer is likely to mitigation request before the expiry of this timer is likely to
be rejected by the DOTS server for the same reasons. be rejected by the DOTS server for the same reasons.
The retry-timer SHOULD be equal to the lifetime of the active The retry-timer SHOULD be equal to the lifetime of the active
mitigation request resulting in the deactivation of the mitigation request resulting in the deactivation of the
skipping to change at page 28, line 8 skipping to change at page 27, line 15
response. If the DOTS server uses the Block2 Option in the GET response. If the DOTS server uses the Block2 Option in the GET
response and the response is for a dynamically changing resource response and the response is for a dynamically changing resource
(e.g. "c=n" or "c=a" query), the DOTS server MUST include the ETag (e.g. "c=n" or "c=a" query), the DOTS server MUST include the ETag
Option in the response. The DOTS client MUST include the same ETag Option in the response. The DOTS client MUST include the same ETag
value in subsequent GET requests to retrieve the rest of the value in subsequent GET requests to retrieve the rest of the
representation. representation.
The following examples illustrate how a DOTS client retrieves active The following examples illustrate how a DOTS client retrieves active
mitigation requests from a DOTS server. In particular: mitigation requests from a DOTS server. In particular:
o Figure 10 shows the example of a GET request to retrieve all DOTS o Figure 11 shows the example of a GET request to retrieve all DOTS
mitigation requests signaled by a DOTS client. mitigation requests signaled by a DOTS client.
o Figure 11 shows the example of a GET request to retrieve a o Figure 12 shows the example of a GET request to retrieve a
specific DOTS mitigation request signaled by a DOTS client. The specific DOTS mitigation request signaled by a DOTS client. The
configuration data to be reported in the response is formatted in configuration data to be reported in the response is formatted in
the same order as was processed by the DOTS server in the original the same order as was processed by the DOTS server in the original
mitigation request. mitigation request.
These two examples assume the default of "c=a"; that is, the DOTS These two examples assume the default of "c=a"; that is, the DOTS
client asks for all data to be reported by the DOTS server. client asks for all data to be reported by the DOTS server.
Header: GET (Code=0.01) Header: GET (Code=0.01)
Uri-Path: ".well-known" Uri-Path: ".well-known"
Uri-Path: "dots" Uri-Path: "dots"
Uri-Path: "mitigate" Uri-Path: "mitigate"
Uri-Path: "cuid=dz6pHjaADkaFTbjr0JGBpw" Uri-Path: "cuid=dz6pHjaADkaFTbjr0JGBpw"
Observe: 0 Observe: 0
Figure 10: GET to Retrieve all DOTS Mitigation Requests Figure 11: GET to Retrieve all DOTS Mitigation Requests
Header: GET (Code=0.01) Header: GET (Code=0.01)
Uri-Path: ".well-known" Uri-Path: ".well-known"
Uri-Path: "dots" Uri-Path: "dots"
Uri-Path: "mitigate" Uri-Path: "mitigate"
Uri-Path: "cuid=dz6pHjaADkaFTbjr0JGBpw" Uri-Path: "cuid=dz6pHjaADkaFTbjr0JGBpw"
Uri-Path: "mid=12332" Uri-Path: "mid=12332"
Observe: 0 Observe: 0
Figure 11: GET to Retrieve a Specific DOTS Mitigation Request Figure 12: GET to Retrieve a Specific DOTS Mitigation Request
If the DOTS server does not find the 'mid' Uri-Path value conveyed in If the DOTS server does not find the 'mid' Uri-Path value conveyed in
the GET request in its configuration data for the requesting DOTS the GET request in its configuration data for the requesting DOTS
client, it MUST respond with a 4.04 (Not Found) error response code. client, it MUST respond with a 4.04 (Not Found) error response code.
Likewise, the same error MUST be returned as a response to a request Likewise, the same error MUST be returned as a response to a request
to retrieve all mitigation records (i.e., 'mid' Uri-Path is not to retrieve all mitigation records (i.e., 'mid' Uri-Path is not
defined) of a given DOTS client if the DOTS server does not find any defined) of a given DOTS client if the DOTS server does not find any
mitigation record for that DOTS client. As a reminder, a DOTS client mitigation record for that DOTS client. As a reminder, a DOTS client
is identified by its identity (e.g., client certificate, 'cuid') and is identified by its identity (e.g., client certificate, 'cuid') and
optionally the 'cdid'. optionally the 'cdid'.
Figure 12 shows a response example of all active mitigation requests Figure 13 shows a response example of all active mitigation requests
associated with the DOTS client as maintained by the DOTS server. associated with the DOTS client as maintained by the DOTS server.
The response indicates the mitigation status of each mitigation The response indicates the mitigation status of each mitigation
request. request.
{ {
"ietf-dots-signal-channel:mitigation-scope": { "ietf-dots-signal-channel:mitigation-scope": {
"scope": [ "scope": [
{ {
"mid": 12332, "mid": 12332,
"mitigation-start": "1507818434", "mitigation-start": "1507818434",
"target-prefix": [ "target-prefix": [
"2001:db8:6401::1/128", "2001:db8:6401::1/128",
"2001:db8:6401::2/128" "2001:db8:6401::2/128"
], ],
"target-protocol": [ "target-protocol": [
17 17
], ],
"lifetime": 1800, "lifetime": 1756,
"status": "attack-successfully-mitigated", "status": "attack-successfully-mitigated",
"bytes-dropped": "134334555", "bytes-dropped": "134334555",
"bps-dropped": "43344", "bps-dropped": "43344",
"pkts-dropped": "333334444", "pkts-dropped": "333334444",
"pps-dropped": "432432" "pps-dropped": "432432"
}, },
{ {
"mid": 12333, "mid": 12333,
"mitigation-start": "1507818393", "mitigation-start": "1507818393",
"target-prefix": [ "target-prefix": [
"2001:db8:6401::1/128", "2001:db8:6401::1/128",
"2001:db8:6401::2/128" "2001:db8:6401::2/128"
], ],
"target-protocol": [ "target-protocol": [
6 6
], ],
"lifetime": 1800, "lifetime": 1755,
"status": "attack-stopped", "status": "attack-stopped",
"bytes-dropped": "0", "bytes-dropped": "0",
"bps-dropped": "0", "bps-dropped": "0",
"pkts-dropped": "0", "pkts-dropped": "0",
"pps-dropped": "0" "pps-dropped": "0"
} }
] ]
} }
} }
Figure 12: Response Body to a GET Request Figure 13: Response Body to a GET Request
The mitigation status parameters are described below: The mitigation status parameters are described below:
mitigation-start: Mitigation start time is expressed in seconds mitigation-start: Mitigation start time is expressed in seconds
relative to 1970-01-01T00:00Z in UTC time (Section 2.4.1 of relative to 1970-01-01T00:00Z in UTC time (Section 2.4.1 of
[RFC7049]). The CBOR encoding is modified so that the leading tag [RFC7049]). The CBOR encoding is modified so that the leading tag
1 (epoch-based date/time) MUST be omitted. 1 (epoch-based date/time) MUST be omitted.
This is a mandatory attribute when an attack mitigation is This is a mandatory attribute when an attack mitigation is active.
triggered. Particularly, 'mitigation-start' is not returned for a Particularly, 'mitigation-start' is not returned for a mitigation
mitigation with 'status' code set to 8. with 'status' code set to 8.
lifetime: The remaining lifetime of the mitigation request, in lifetime: The remaining lifetime of the mitigation request, in
seconds. seconds.
This is a mandatory attribute. This is a mandatory attribute.
status: Status of attack mitigation. The various possible values of status: Status of attack mitigation. The various possible values of
'status' parameter are explained in Table 2. 'status' parameter are explained in Table 2.
This is a mandatory attribute. This is a mandatory attribute.
bytes-dropped: The total dropped byte count for the mitigation bytes-dropped: The total dropped byte count for the mitigation
request since the attack mitigation is triggered. The count wraps request since the attack mitigation is triggered. The count wraps
around when it reaches the maximum value of unsigned integer64. around when it reaches the maximum value of unsigned integer64.
This is an optional attribute. This is an optional attribute.
bps-dropped: The average number of dropped bytes per second for the bps-dropped: The average number of dropped bytes per second for the
mitigation request since the attack mitigation is triggered. This mitigation request since the attack mitigation is triggered. This
SHOULD be a five-minute average. average SHOULD be over five-minute intervals.
This is an optional attribute. This is an optional attribute.
pkts-dropped: The total number of dropped packet count for the pkts-dropped: The total number of dropped packet count for the
mitigation request since the attack mitigation is triggered. The mitigation request since the attack mitigation is triggered. The
count wraps around when it reaches the maximum value of unsigned count wraps around when it reaches the maximum value of unsigned
integer64. integer64.
This is an optional attribute. This is an optional attribute.
pps-dropped: The average number of dropped packets per second for pps-dropped: The average number of dropped packets per second for
the mitigation request since the attack mitigation is triggered. the mitigation request since the attack mitigation is triggered.
This SHOULD be a five-minute average. This average SHOULD be over five-minute intervals.
This is an optional attribute. This is an optional attribute.
+-----------+-------------------------------------------------------+ +-----------+-------------------------------------------------------+
| Parameter | Description | | Parameter | Description |
| Value | | | Value | |
+-----------+-------------------------------------------------------+ +-----------+-------------------------------------------------------+
| 1 | Attack mitigation setup is in progress (e.g., | | 1 | Attack mitigation setup is in progress (e.g., |
| | changing the network path to redirect the inbound | | | changing the network path to redirect the inbound |
| | traffic to a DOTS mitigator). | | | traffic to a DOTS mitigator). |
skipping to change at page 31, line 34 skipping to change at page 31, line 34
| | transition to "8". | | | transition to "8". |
+-----------+-------------------------------------------------------+ +-----------+-------------------------------------------------------+
| 4 | Attack has exceeded the mitigation provider | | 4 | Attack has exceeded the mitigation provider |
| | capability. | | | capability. |
+-----------+-------------------------------------------------------+ +-----------+-------------------------------------------------------+
| 5 | DOTS client has withdrawn the mitigation request and | | 5 | DOTS client has withdrawn the mitigation request and |
| | the mitigation is active but terminating. | | | the mitigation is active but terminating. |
+-----------+-------------------------------------------------------+ +-----------+-------------------------------------------------------+
| 6 | Attack mitigation is now terminated. | | 6 | Attack mitigation is now terminated. |
+-----------+-------------------------------------------------------+ +-----------+-------------------------------------------------------+
| 7 | Attack mitigation is withdrawn. If a mitigation | | 7 | Attack mitigation is withdrawn (by the DOTS server). |
| | request with 'trigger-mitigation' set to false is | | | If a mitigation request with 'trigger-mitigation' set |
| | withdrawn because it overlaps with an immediate | | | to false is withdrawn because it overlaps with an |
| | mitigation request, this status code will be | | | immediate mitigation request, this status code will |
| | transmitted 4 times and then transition to "8" for | | | be transmitted 4 times and then transition to "8" for |
| | the mitigation request with pre-configured scopes. | | | the mitigation request with pre-configured scopes. |
+-----------+-------------------------------------------------------+ +-----------+-------------------------------------------------------+
| 8 | Attack mitigation will be triggered for the | | 8 | Attack mitigation will be triggered for the |
| | mitigation request only when the DOTS signal channel | | | mitigation request only when the DOTS signal channel |
| | session is lost. | | | session is lost. |
+-----------+-------------------------------------------------------+ +-----------+-------------------------------------------------------+
Table 2: Values of 'status' Parameter Table 2: Values of 'status' Parameter
4.4.2.1. DOTS Servers Sending Mitigation Status 4.4.2.1. DOTS Servers Sending Mitigation Status
skipping to change at page 32, line 16 skipping to change at page 32, line 16
implementations MUST use the Observe Option for both 'mitigate' and implementations MUST use the Observe Option for both 'mitigate' and
'config' (Section 4.2). 'config' (Section 4.2).
A DOTS client conveys the Observe Option set to '0' in the GET A DOTS client conveys the Observe Option set to '0' in the GET
request to receive asynchronous notifications of attack mitigation request to receive asynchronous notifications of attack mitigation
status from the DOTS server. status from the DOTS server.
Unidirectional mitigation notifications within the bidirectional Unidirectional mitigation notifications within the bidirectional
signal channel enables asynchronous notifications between the agents. signal channel enables asynchronous notifications between the agents.
[RFC7641] indicates that (1) a notification can be sent in a [RFC7641] indicates that (1) a notification can be sent in a
Confirmable (CON) or a Non-confirmable (NON) message, and (2) the Confirmable or a Non-confirmable message, and (2) the message type
message type used is typically application dependent and may be used is typically application dependent and may be determined by the
determined by the server for each notification individually. For server for each notification individually. For DOTS server
DOTS server application, the message type MUST always be set to Non- application, the message type MUST always be set to Non-confirmable
confirmable even if the underlying COAP library elects a notification even if the underlying COAP library elects a notification to be sent
to be sent in a Confirmable message. in a Confirmable message.
Due to the higher likelihood of packet loss during a DDoS attack, the Due to the higher likelihood of packet loss during a DDoS attack, the
DOTS server periodically sends attack mitigation status to the DOTS DOTS server periodically sends attack mitigation status to the DOTS
client and also notifies the DOTS client whenever the status of the client and also notifies the DOTS client whenever the status of the
attack mitigation changes. If the DOTS server cannot maintain an RTT attack mitigation changes. If the DOTS server cannot maintain an RTT
estimate, it SHOULD NOT send more than one asynchronous notification estimate, it SHOULD NOT send more than one asynchronous notification
every 3 seconds, and SHOULD use an even less aggressive rate whenever every 3 seconds, and SHOULD use an even less aggressive rate whenever
possible (case 2 in Section 3.1.3 of [RFC8085]). possible (case 2 in Section 3.1.3 of [RFC8085]).
When conflicting requests are detected, the DOTS server enforces the When conflicting requests are detected, the DOTS server enforces the
skipping to change at page 33, line 19 skipping to change at page 33, line 19
means to alert administrators about mitigation conflicts. means to alert administrators about mitigation conflicts.
A DOTS client that is no longer interested in receiving notifications A DOTS client that is no longer interested in receiving notifications
from the DOTS server can simply "forget" the observation. When the from the DOTS server can simply "forget" the observation. When the
DOTS server sends the next notification, the DOTS client will not DOTS server sends the next notification, the DOTS client will not
recognize the token in the message and thus will return a Reset recognize the token in the message and thus will return a Reset
message. This causes the DOTS server to remove the associated entry. message. This causes the DOTS server to remove the associated entry.
Alternatively, the DOTS client can explicitly deregister itself by Alternatively, the DOTS client can explicitly deregister itself by
issuing a GET request that has the Token field set to the token of issuing a GET request that has the Token field set to the token of
the observation to be cancelled and includes an Observe Option with the observation to be cancelled and includes an Observe Option with
the value set to '1' (deregister). the value set to '1' (deregister). The latter is RECOMMENDED.
Figure 13 shows an example of a DOTS client requesting a DOTS server Figure 14 shows an example of a DOTS client requesting a DOTS server
to send notifications related to a mitigation request. Note that for to send notifications related to a mitigation request. Note that for
mitigations with pre-configured scopes (i.e., 'trigger-mitigation' mitigations with pre-configured scopes (i.e., 'trigger-mitigation'
set to 'false'), the state will need to transition from 3 (attack- set to 'false'), the state will need to transition from 3 (attack-
stopped) to 8 (attack-mitigation-signal-loss). stopped) to 8 (attack-mitigation-signal-loss).
+-----------+ +-----------+ +-----------+ +-----------+
|DOTS client| |DOTS server| |DOTS client| |DOTS server|
+-----------+ +-----------+ +-----------+ +-----------+
| | | |
| GET /<mid> | | GET /<mid> |
skipping to change at page 34, line 34 skipping to change at page 34, line 34
| | | |
|<-----------------------------------------+ |<-----------------------------------------+
| 2.05 Content | | 2.05 Content |
| Token: 0x4a | Notification upon | Token: 0x4a | Notification upon
| Observe: 60 | a state change | Observe: 60 | a state change
| status: "attack-stopped" | | status: "attack-stopped" |
|<-----------------------------------------+ |<-----------------------------------------+
| | | |
... ...
Figure 13: Notifications of Attack Mitigation Status Figure 14: Notifications of Attack Mitigation Status
4.4.2.2. DOTS Clients Polling for Mitigation Status 4.4.2.2. DOTS Clients Polling for Mitigation Status
The DOTS client can send the GET request at frequent intervals The DOTS client can send the GET request at frequent intervals
without the Observe Option to retrieve the configuration data of the without the Observe Option to retrieve the configuration data of the
mitigation request and non-configuration data (i.e., the attack mitigation request and non-configuration data (i.e., the attack
status). The frequency of polling the DOTS server to get the status). The frequency of polling the DOTS server to get the
mitigation status SHOULD follow the transmission guidelines in mitigation status SHOULD follow the transmission guidelines in
Section 3.1.3 of [RFC8085]. Section 3.1.3 of [RFC8085].
If the DOTS server has been able to mitigate the attack and the If the DOTS server has been able to mitigate the attack and the
attack has stopped, the DOTS server indicates as such in the status. attack has stopped, the DOTS server indicates as such in the status.
In such case, the DOTS client recalls the mitigation request by In such case, the DOTS client recalls the mitigation request by
issuing a DELETE request for this mitigation request (Section 4.4.4). issuing a DELETE request for this mitigation request (Section 4.4.4).
A DOTS client SHOULD react to the status of the attack as per the A DOTS client SHOULD react to the status of the attack as per the
information sent by the DOTS server rather than acknowledging by information sent by the DOTS server rather than performing its own
itself, using its own means, that the attack has been mitigated. detection that the attack has been mitigated. This ensures that the
DOTS client does not recall a mitigation request prematurely because
This ensures that the DOTS client does not recall a mitigation it is possible that the DOTS client does not sense the DDoS attack on
request prematurely because it is possible that the DOTS client does its resources, but the DOTS server could be actively mitigating the
not sense the DDoS attack on its resources, but the DOTS server could attack because the attack is not completely averted.
be actively mitigating the attack because the attack is not
completely averted.
4.4.3. Efficacy Update from DOTS Clients 4.4.3. Efficacy Update from DOTS Clients
While DDoS mitigation is in progress, due to the likelihood of packet While DDoS mitigation is in progress, due to the likelihood of packet
loss, a DOTS client MAY periodically transmit DOTS mitigation loss, a DOTS client MAY periodically transmit DOTS mitigation
efficacy updates to the relevant DOTS server. A PUT request is used efficacy updates to the relevant DOTS server. A PUT request is used
to convey the mitigation efficacy update to the DOTS server. This to convey the mitigation efficacy update to the DOTS server. This
PUT request is treated as a refresh of the current mitigation. PUT request is treated as a refresh of the current mitigation.
The PUT request used for efficacy update MUST include all the The PUT request used for efficacy update MUST include all the
skipping to change at page 35, line 39 skipping to change at page 35, line 37
may send a PUT request to convey an efficacy update to the DOTS may send a PUT request to convey an efficacy update to the DOTS
server followed by a DELETE request to withdraw the mitigation server followed by a DELETE request to withdraw the mitigation
request, but the DELETE request arrives at the DOTS server before the request, but the DELETE request arrives at the DOTS server before the
PUT request. To handle out-of-order delivery of requests, if an If- PUT request. To handle out-of-order delivery of requests, if an If-
Match Option is present in the PUT request and the 'mid' in the Match Option is present in the PUT request and the 'mid' in the
request matches a mitigation request from that DOTS client, the request matches a mitigation request from that DOTS client, the
request is processed by the DOTS server. If no match is found, the request is processed by the DOTS server. If no match is found, the
PUT request is silently ignored by the DOTS server. PUT request is silently ignored by the DOTS server.
An example of an efficacy update message, which includes an If-Match An example of an efficacy update message, which includes an If-Match
Option with an empty value, is depicted in Figure 14. Option with an empty value, is depicted in Figure 15.
Header: PUT (Code=0.03) Header: PUT (Code=0.03)
Uri-Path: ".well-known" Uri-Path: ".well-known"
Uri-Path: "dots" Uri-Path: "dots"
Uri-Path: "mitigate" Uri-Path: "mitigate"
Uri-Path: "cuid=dz6pHjaADkaFTbjr0JGBpw" Uri-Path: "cuid=dz6pHjaADkaFTbjr0JGBpw"
Uri-Path: "mid=123" Uri-Path: "mid=123"
Content-Format: "application/dots+cbor" Content-Format: "application/dots+cbor"
If-Match: If-Match:
{ {
"ietf-dots-signal-channel:mitigation-scope": { "ietf-dots-signal-channel:mitigation-scope": {
"scope": [ "scope": [
{ {
"target-prefix": [ "target-prefix": [
"string" "2001:db8:6401::1/128",
"2001:db8:6401::2/128"
], ],
"target-port-range": [ "target-port-range": [
{ {
"lower-port": number, "lower-port": 80
"upper-port": number },
} {
], "lower-port": 443
"target-protocol": [ },
number {
], "lower-port": 8080
"target-fqdn": [ }
"string" ],
], "target-protocol": [
"target-uri": [ 6
"string" ],
], "attack-status": "under-attack"
"alias-name": [
"string"
],
"lifetime": number,
"attack-status": "string"
} }
] ]
} }
} }
Figure 14: Efficacy Update Figure 15: An Example of Efficacy Update
The 'attack-status' parameter is a mandatory attribute when The 'attack-status' parameter is a mandatory attribute when
performing an efficacy update. The various possible values contained performing an efficacy update. The various possible values contained
in the 'attack-status' parameter are described in Table 3. in the 'attack-status' parameter are described in Table 3.
+---------------------------------+---------------------------------+ +-----------+-------------------------------------------------------+
| Parameter value | Description | | Parameter | Description |
+---------------------------------+---------------------------------+ | value | |
| 1 (under-attack) | The DOTS client determines that | +-----------+-------------------------------------------------------+
| | it is still under attack. | | 1 | The DOTS client determines that it is still under |
+---------------------------------+---------------------------------+ | | attack. |
| 2 (attack-successfully- | The DOTS client determines that | +-----------+-------------------------------------------------------+
| mitigated) | the attack is successfully | | 2 | The DOTS client determines that the attack is |
| | mitigated (e.g., attack traffic | | | successfully mitigated (e.g., attack traffic is not |
| | is not seen). | | | seen). |
+---------------------------------+---------------------------------+ +-----------+-------------------------------------------------------+
Table 3: Values of 'attack-status' Parameter Table 3: Values of 'attack-status' Parameter
The DOTS server indicates the result of processing a PUT request The DOTS server indicates the result of processing a PUT request
using CoAP response codes. The response code 2.04 (Changed) is using CoAP response codes. The response code 2.04 (Changed) is
returned if the DOTS server has accepted the mitigation efficacy returned if the DOTS server has accepted the mitigation efficacy
update. The error response code 5.03 (Service Unavailable) is update. The error response code 5.03 (Service Unavailable) is
returned if the DOTS server has erred or is incapable of performing returned if the DOTS server has erred or is incapable of performing
the mitigation. the mitigation. As specified in [RFC7252], 5.03 uses Max-Age option
to indicate the number of seconds after which to retry.
4.4.4. Withdraw a Mitigation 4.4.4. Withdraw a Mitigation
DELETE requests are used to withdraw DOTS mitigation requests from DELETE requests are used to withdraw DOTS mitigation requests from
DOTS servers (Figure 15). DOTS servers (Figure 16).
'cuid' and 'mid' are mandatory Uri-Path parameters for DELETE 'cuid' and 'mid' are mandatory Uri-Path parameters for DELETE
requests. requests.
The same considerations for manipulating 'cdid' parameter by DOTS The same considerations for manipulating 'cdid' parameter by DOTS
gateways, as specified in Section 4.4.1, MUST be followed for DELETE gateways, as specified in Section 4.4.1, MUST be followed for DELETE
requests. Uri-Path parameters with empty values MUST NOT be present requests. Uri-Path parameters with empty values MUST NOT be present
in a request. in a request.
Header: DELETE (Code=0.04) Header: DELETE (Code=0.04)
Uri-Path: ".well-known" Uri-Path: ".well-known"
Uri-Path: "dots" Uri-Path: "dots"
Uri-Path: "mitigate" Uri-Path: "mitigate"
Uri-Path: "cuid=dz6pHjaADkaFTbjr0JGBpw" Uri-Path: "cuid=dz6pHjaADkaFTbjr0JGBpw"
Uri-Path: "mid=123" Uri-Path: "mid=123"
Figure 15: Withdraw a DOTS Mitigation Figure 16: Withdraw a DOTS Mitigation
If the DELETE request does not include 'cuid' and 'mid' parameters, If the DELETE request does not include 'cuid' and 'mid' parameters,
the DOTS server MUST reply with a 4.00 (Bad Request). the DOTS server MUST reply with a 4.00 (Bad Request).
Once the request is validated, the DOTS server immediately Once the request is validated, the DOTS server immediately
acknowledges a DOTS client's request to withdraw the DOTS signal acknowledges a DOTS client's request to withdraw the DOTS signal
using 2.02 (Deleted) response code with no response payload. A 2.02 using 2.02 (Deleted) response code with no response payload. A 2.02
(Deleted) Response Code is returned even if the 'mid' parameter value (Deleted) Response Code is returned even if the 'mid' parameter value
conveyed in the DELETE request does not exist in its configuration conveyed in the DELETE request does not exist in its configuration
data before the request. data before the request.
skipping to change at page 38, line 24 skipping to change at page 38, line 27
limited period after acknowledging a DOTS client's withdrawal of a limited period after acknowledging a DOTS client's withdrawal of a
mitigation request. During this period, the DOTS server status mitigation request. During this period, the DOTS server status
messages SHOULD indicate that mitigation is active but terminating messages SHOULD indicate that mitigation is active but terminating
(Section 4.4.2). (Section 4.4.2).
The initial active-but-terminating period SHOULD be sufficiently long The initial active-but-terminating period SHOULD be sufficiently long
to absorb latency incurred by route propagation. The active-but- to absorb latency incurred by route propagation. The active-but-
terminating period SHOULD be set by default to 120 seconds. If the terminating period SHOULD be set by default to 120 seconds. If the
client requests mitigation again before the initial active-but- client requests mitigation again before the initial active-but-
terminating period elapses, the DOTS server MAY exponentially terminating period elapses, the DOTS server MAY exponentially
increase the active-but-terminating period up to a maximum of 300 increase (the exponent is 2) the active-but-terminating period up to
seconds (5 minutes). a maximum of 300 seconds (5 minutes).
Once the active-but-terminating period elapses, the DOTS server MUST Once the active-but-terminating period elapses, the DOTS server MUST
treat the mitigation as terminated, as the DOTS client is no longer treat the mitigation as terminated, as the DOTS client is no longer
responsible for the mitigation. For example, if there is a financial responsible for the mitigation. For example, if there is a financial
relationship between the DOTS client and server domains, the DOTS relationship between the DOTS client and server domains, the DOTS
client stops incurring cost at this point. client stops incurring cost at this point.
If a mitigation is triggered due to a signal channel loss, the DOTS If a mitigation is triggered due to a signal channel loss, the DOTS
server relies upon normal triggers to stop that mitigation server relies upon normal triggers to stop that mitigation
(typically, receipt of a valid DELETE request, expiry of the (typically, receipt of a valid DELETE request, expiry of the
mitigation lifetime, or observation of traffic to the attack target). mitigation lifetime, or scrubbing the traffic to the attack target).
In particular, the DOTS server MUST NOT consider the signal channel In particular, the DOTS server MUST NOT consider the signal channel
recovery as a trigger to stop the mitigation. recovery as a trigger to stop the mitigation.
4.5. DOTS Signal Channel Session Configuration 4.5. DOTS Signal Channel Session Configuration
A DOTS client can negotiate, configure, and retrieve the DOTS signal A DOTS client can negotiate, configure, and retrieve the DOTS signal
channel session behavior with its DOTS peers. The DOTS signal channel session behavior with its DOTS peers. The DOTS signal
channel can be used, for example, to configure the following: channel can be used, for example, to configure the following:
a. Heartbeat interval (heartbeat-interval): DOTS agents regularly a. Heartbeat interval (heartbeat-interval): DOTS agents regularly
skipping to change at page 39, line 28 skipping to change at page 39, line 30
heartbeat exchanges when an active DOTS client has not requested heartbeat exchanges when an active DOTS client has not requested
mitigation. If distinct configurations are used, DOTS agents MUST mitigation. If distinct configurations are used, DOTS agents MUST
follow the appropriate configuration set as a function of the follow the appropriate configuration set as a function of the
mitigation activity (e.g., if no mitigation request is active, 'idle- mitigation activity (e.g., if no mitigation request is active, 'idle-
config'-related values must be followed). Additionally, DOTS agents config'-related values must be followed). Additionally, DOTS agents
MUST automatically switch to the other configuration upon a change in MUST automatically switch to the other configuration upon a change in
the mitigation activity (e.g., if an attack mitigation is launched the mitigation activity (e.g., if an attack mitigation is launched
after a peacetime, the DOTS agent switches from 'idle-config' to after a peacetime, the DOTS agent switches from 'idle-config' to
'mitigating-config'-related values). 'mitigating-config'-related values).
Requests and responses are deemed reliable by marking them as CoAP Requests and responses are indicated for reliable delivery by
Confirmable messages. DOTS signal channel session configuration marking them as Confirmable messages. DOTS signal channel session
requests and responses are marked as Confirmable messages. As configuration requests and responses are marked as Confirmable
explained in Section 2.1 of [RFC7252], a Confirmable message is messages. As explained in Section 2.1 of [RFC7252], a Confirmable
retransmitted using a default timeout and exponential back-off message is retransmitted using a default timeout and exponential
between retransmissions, until the DOTS server sends an back-off between retransmissions, until the DOTS server sends an
Acknowledgement message (ACK) with the same Message ID conveyed from Acknowledgement message (ACK) with the same Message ID conveyed from
the DOTS client. the DOTS client.
Message transmission parameters are defined in Section 4.8 of Message transmission parameters are defined in Section 4.8 of
[RFC7252]. The DOTS server can either piggyback the response in the [RFC7252]. The DOTS server can either piggyback the response in the
acknowledgement message or, if the DOTS server cannot respond acknowledgement message or, if the DOTS server cannot respond
immediately to a request carried in a Confirmable message, it simply immediately to a request carried in a Confirmable message, it simply
responds with an Empty Acknowledgement message so that the DOTS responds with an Empty Acknowledgement message so that the DOTS
client can stop retransmitting the request. Empty Acknowledgement client can stop retransmitting the request. Empty Acknowledgement
message is explained in Section 2.2 of [RFC7252]. When the response messages are explained in Section 2.2 of [RFC7252]. When the
is ready, the server sends it in a new Confirmable message which in response is ready, the server sends it in a new Confirmable message
turn needs to be acknowledged by the DOTS client (see Sections 5.2.1 which in turn needs to be acknowledged by the DOTS client (see
and 5.2.2 of [RFC7252]). Requests and responses exchanged between Sections 5.2.1 and 5.2.2 of [RFC7252]). Requests and responses
DOTS agents during peacetime are marked as Confirmable messages. exchanged between DOTS agents during peacetime are marked as
Confirmable messages.
Implementation Note: A DOTS client that receives a response in a Implementation Note: A DOTS client that receives a response in a
CON message may want to clean up the message state right after Confirmable message may want to clean up the message state right
sending the ACK. If that ACK is lost and the DOTS server after sending the ACK. If that ACK is lost and the DOTS server
retransmits the CON, the DOTS client may no longer have any state retransmits the Confirmable message, the DOTS client may no longer
that would help it correlate this response: from the DOTS client's have any state that would help it correlate this response: from
standpoint, the retransmission message is unexpected. The DOTS the DOTS client's standpoint, the retransmission message is
client will send a Reset message so it does not receive any more unexpected. The DOTS client will send a Reset message so it does
retransmissions. This behavior is normal and not an indication of not receive any more retransmissions. This behavior is normal and
an error (see Section 5.3.2 of [RFC7252] for more details). not an indication of an error (see Section 5.3.2 of [RFC7252] for
more details).
4.5.1. Discover Configuration Parameters 4.5.1. Discover Configuration Parameters
A GET request is used to obtain acceptable (e.g., minimum and maximum A GET request is used to obtain acceptable (e.g., minimum and maximum
values) and current configuration parameters on the DOTS server for values) and current configuration parameters on the DOTS server for
DOTS signal channel session configuration. This procedure occurs DOTS signal channel session configuration. This procedure occurs
between a DOTS client and its immediate peer DOTS server. As such, between a DOTS client and its immediate peer DOTS server. As such,
this GET request MUST NOT be relayed by an on-path DOTS gateway. this GET request MUST NOT be relayed by a DOTS gateway.
Figure 16 shows how to obtain acceptable configuration parameters for Figure 17 shows how to obtain acceptable configuration parameters for
the DOTS server. the DOTS server.
Header: GET (Code=0.01) Header: GET (Code=0.01)
Uri-Path: ".well-known" Uri-Path: ".well-known"
Uri-Path: "dots" Uri-Path: "dots"
Uri-Path: "config" Uri-Path: "config"
Figure 16: GET to Retrieve Configuration Figure 17: GET to Retrieve Configuration
The DOTS server in the 2.05 (Content) response conveys the current, The DOTS server in the 2.05 (Content) response conveys the current,
minimum, and maximum attribute values acceptable by the DOTS server minimum, and maximum attribute values acceptable by the DOTS server
(Figure 17). (Figure 18).
Content-Format: "application/dots+cbor" Content-Format: "application/dots+cbor"
{ {
"ietf-dots-signal-channel:signal-config": { "ietf-dots-signal-channel:signal-config": {
"mitigating-config": { "mitigating-config": {
"heartbeat-interval": { "heartbeat-interval": {
"max-value": number, "max-value": number,
"min-value": number, "min-value": number,
"current-value": number "current-value": number
}, },
skipping to change at page 41, line 44 skipping to change at page 41, line 49
}, },
"ack-random-factor": { "ack-random-factor": {
"max-value-decimal": "string", "max-value-decimal": "string",
"min-value-decimal": "string", "min-value-decimal": "string",
"current-value-decimal": "string" "current-value-decimal": "string"
} }
} }
} }
} }
Figure 17: GET Configuration Response Body Figure 18: GET Configuration Response Body Schema
The parameters in Figure 17 are described below: The parameters in Figure 18 are described below:
mitigating-config: Set of configuration parameters to use when a mitigating-config: Set of configuration parameters to use when a
mitigation is active. The following parameters may be included: mitigation is active. The following parameters may be included:
heartbeat-interval: Time interval in seconds between two heartbeat-interval: Time interval in seconds between two
consecutive heartbeat messages. consecutive heartbeat messages.
'0' is used to disable the heartbeat mechanism. '0' is used to disable the heartbeat mechanism.
This is an optional attribute. This is an optional attribute.
skipping to change at page 42, line 39 skipping to change at page 42, line 42
ack-random-factor: Random factor used to influence the timing of ack-random-factor: Random factor used to influence the timing of
retransmissions (referred to as ACK_RANDOM_FACTOR parameter in retransmissions (referred to as ACK_RANDOM_FACTOR parameter in
CoAP). CoAP).
This is an optional attribute. This is an optional attribute.
idle-config: Set of configuration parameters to use when no idle-config: Set of configuration parameters to use when no
mitigation is active. This attribute has the same structure as mitigation is active. This attribute has the same structure as
'mitigating-config'. 'mitigating-config'.
Figure 18 shows an example of acceptable and current configuration Figure 19 shows an example of acceptable and current configuration
parameters on a DOTS server for DOTS signal channel session parameters on a DOTS server for DOTS signal channel session
configuration. The same acceptable configuration is used during configuration. The same acceptable configuration is used during
attack and peace times. mitigation and idle times.
Content-Format: "application/dots+cbor" Content-Format: "application/dots+cbor"
{ {
"ietf-dots-signal-channel:signal-config": { "ietf-dots-signal-channel:signal-config": {
"mitigating-config": { "mitigating-config": {
"heartbeat-interval": { "heartbeat-interval": {
"max-value": 240, "max-value": 240,
"min-value": 15, "min-value": 15,
"current-value": 30 "current-value": 30
}, },
skipping to change at page 43, line 15 skipping to change at page 43, line 18
"max-value": 9, "max-value": 9,
"min-value": 3, "min-value": 3,
"current-value": 5 "current-value": 5
}, },
"max-retransmit": { "max-retransmit": {
"max-value": 15, "max-value": 15,
"min-value": 2, "min-value": 2,
"current-value": 3 "current-value": 3
}, },
"ack-timeout": { "ack-timeout": {
"max-value-decimal": "30.0", "max-value-decimal": "30.00",
"min-value-decimal": "1.0", "min-value-decimal": "1.00",
"current-value-decimal": "2.0" "current-value-decimal": "2.00"
}, },
"ack-random-factor": { "ack-random-factor": {
"max-value-decimal": "4.0", "max-value-decimal": "4.00",
"min-value-decimal": "1.1", "min-value-decimal": "1.10",
"current-value-decimal": "1.5" "current-value-decimal": "1.50"
} }
}, },
"idle-config": { "idle-config": {
"heartbeat-interval": { "heartbeat-interval": {
"max-value": 240, "max-value": 240,
"min-value": 15, "min-value": 15,
"current-value": 30 "current-value": 30
}, },
"missing-hb-allowed": { "missing-hb-allowed": {
"max-value": 9, "max-value": 9,
"min-value": 3, "min-value": 3,
"current-value": 5 "current-value": 5
}, },
"max-retransmit": { "max-retransmit": {
"max-value": 15, "max-value": 15,
"min-value": 2, "min-value": 2,
"current-value": 3 "current-value": 3
}, },
"ack-timeout": { "ack-timeout": {
"max-value-decimal": "30.0", "max-value-decimal": "30.00",
"min-value-decimal": "1.0", "min-value-decimal": "1.00",
"current-value-decimal": "2.0" "current-value-decimal": "2.00"
}, },
"ack-random-factor": { "ack-random-factor": {
"max-value-decimal": "4.0", "max-value-decimal": "4.00",
"min-value-decimal": "1.1", "min-value-decimal": "1.10",
"current-value-decimal": "1.5" "current-value-decimal": "1.50"
} }
} }
} }
} }
Figure 18: Example of a Configuration Response Body Figure 19: Example of a Configuration Response Body
4.5.2. Convey DOTS Signal Channel Session Configuration 4.5.2. Convey DOTS Signal Channel Session Configuration
A PUT request is used to convey the configuration parameters for the A PUT request (Figures 20 and 21) is used to convey the configuration
signal channel (e.g., heartbeat interval, maximum retransmissions). parameters for the signal channel (e.g., heartbeat interval, maximum
Message transmission parameters for CoAP are defined in Section 4.8 retransmissions). Message transmission parameters for CoAP are
of [RFC7252]. The RECOMMENDED values of transmission parameter defined in Section 4.8 of [RFC7252]. The RECOMMENDED values of
values are ack-timeout (2 seconds), max-retransmit (3), ack-random- transmission parameter values are ack-timeout (2 seconds), max-
factor (1.5). In addition to those parameters, the RECOMMENDED retransmit (3), ack-random-factor (1.5). In addition to those
specific DOTS transmission parameter values are 'heartbeat-interval' parameters, the RECOMMENDED specific DOTS transmission parameter
(30 seconds) and 'missing-hb-allowed' (5). values are 'heartbeat-interval' (30 seconds) and 'missing-hb-allowed'
(5).
Note: heartbeat-interval should be tweaked to also assist DOTS Note: heartbeat-interval should be tweaked to also assist DOTS
messages for NAT traversal (SIG-011 of messages for NAT traversal (SIG-011 of
[I-D.ietf-dots-requirements]). According to [RFC8085], keepalive [I-D.ietf-dots-requirements]). According to [RFC8085], keepalive
messages must not be sent more frequently than once every 15 messages must not be sent more frequently than once every 15
seconds and should use longer intervals when possible. seconds and should use longer intervals when possible.
Furthermore, [RFC4787] recommends NATs to use a state timeout of 2 Furthermore, [RFC4787] recommends NATs to use a state timeout of 2
minutes or longer, but experience shows that sending packets every minutes or longer, but experience shows that sending packets every
15 to 30 seconds is necessary to prevent the majority of 15 to 30 seconds is necessary to prevent the majority of
middleboxes from losing state for UDP flows. From that middleboxes from losing state for UDP flows. From that
skipping to change at page 44, line 47 skipping to change at page 44, line 50
negotiate longer heartbeat-interval values to prevent any network negotiate longer heartbeat-interval values to prevent any network
overload with too frequent keepalives. overload with too frequent keepalives.
Different heartbeat intervals can be defined for 'mitigating- Different heartbeat intervals can be defined for 'mitigating-
config' and 'idle-config' to reduce being too chatty during idle config' and 'idle-config' to reduce being too chatty during idle
times. If there is an on-path translator between the DOTS client times. If there is an on-path translator between the DOTS client
(standalone or part of a DOTS gateway) and the DOTS server, the (standalone or part of a DOTS gateway) and the DOTS server, the
'mitigating-config' heartbeat-interval has to be smaller than the 'mitigating-config' heartbeat-interval has to be smaller than the
translator session timeout. It is recommended that the 'idle- translator session timeout. It is recommended that the 'idle-
config' heartbeat-interval is also smaller than the translator config' heartbeat-interval is also smaller than the translator
session timeout to prevent translator traversal issues, or set to session timeout to prevent translator traversal issues, or
'0'. Means to discover the lifetime assigned by a translator are disabled entirely. Means to discover the lifetime assigned by a
out of scope. translator are out of scope.
When a Confirmable "CoAP Ping" is sent, and if there is no response, When a Confirmable "CoAP Ping" is sent, and if there is no response,
the "CoAP Ping" is retransmitted max-retransmit number of times by the "CoAP Ping" is retransmitted max-retransmit number of times by
the CoAP layer using an initial timeout set to a random duration the CoAP layer using an initial timeout set to a random duration
between ack-timeout and (ack-timeout*ack-random-factor) and between ack-timeout and (ack-timeout*ack-random-factor) and
exponential back-off between retransmissions. By choosing the exponential back-off between retransmissions. By choosing the
recommended transmission parameters, the "CoAP Ping" will timeout recommended transmission parameters, the "CoAP Ping" will timeout
after 45 seconds. If the DOTS agent does not receive any response after 45 seconds. If the DOTS agent does not receive any response
from the peer DOTS agent for 'missing-hb-allowed' number of from the peer DOTS agent for 'missing-hb-allowed' number of
consecutive "CoAP Ping" Confirmable messages, it concludes that the consecutive "CoAP Ping" Confirmable messages, it concludes that the
skipping to change at page 46, line 12 skipping to change at page 45, line 37
DOTS signal channel session between DOTS agents, so the 'cuid' Uri- DOTS signal channel session between DOTS agents, so the 'cuid' Uri-
Path MUST NOT be used. Path MUST NOT be used.
Header: PUT (Code=0.03) Header: PUT (Code=0.03)
Uri-Path: ".well-known" Uri-Path: ".well-known"
Uri-Path: "dots" Uri-Path: "dots"
Uri-Path: "config" Uri-Path: "config"
Uri-Path: "sid=123" Uri-Path: "sid=123"
Content-Format: "application/dots+cbor" Content-Format: "application/dots+cbor"
{ {
...
}
Figure 20: PUT to Convey the DOTS Signal Channel Session
Configuration Data
The additional Uri-Path parameter to those defined in Table 1 is as
follows:
sid: Session Identifier is an identifier for the DOTS signal channel
session configuration data represented as an integer. This
identifier MUST be generated by DOTS clients. 'sid' values MUST
increase monotonically (when a new PUT is generated by a DOTS
client to convey the configuration parameters for the signal
channel).
This is a mandatory attribute.
Content-Format: "application/dots+cbor"
{
"ietf-dots-signal-channel:signal-config": { "ietf-dots-signal-channel:signal-config": {
"mitigating-config": { "mitigating-config": {
"heartbeat-interval": { "heartbeat-interval": {
"current-value": number "current-value": number
}, },
"missing-hb-allowed": { "missing-hb-allowed": {
"current-value": number "current-value": number
}, },
"max-retransmit": { "max-retransmit": {
"current-value": number "current-value": number
skipping to change at page 46, line 50 skipping to change at page 46, line 47
"ack-timeout": { "ack-timeout": {
"current-value-decimal": "string" "current-value-decimal": "string"
}, },
"ack-random-factor": { "ack-random-factor": {
"current-value-decimal": "string" "current-value-decimal": "string"
} }
} }
} }
} }
Figure 19: PUT to Convey the DOTS Signal Channel Session Figure 21: PUT to Convey the DOTS Signal Channel Session
Configuration Data Configuration Data (Message Body Schema)
The additional Uri-Path parameter to those defined in Table 1 is as
follows:
sid: Session Identifier is an identifier for the DOTS signal channel
session configuration data represented as an integer. This
identifier MUST be generated by DOTS clients. 'sid' values MUST
increase monotonically.
This is a mandatory attribute.
The meaning of the parameters in the CBOR body is defined in The meaning of the parameters in the CBOR body (Figure 21) is defined
Section 4.5.1. in Section 4.5.1.
At least one of the attributes 'heartbeat-interval', 'missing-hb- At least one of the attributes 'heartbeat-interval', 'missing-hb-
allowed', 'max-retransmit', 'ack-timeout', and 'ack-random-factor' allowed', 'max-retransmit', 'ack-timeout', and 'ack-random-factor'
MUST be present in the PUT request. Note that 'heartbeat-interval', MUST be present in the PUT request. Note that 'heartbeat-interval',
'missing-hb-allowed', 'max-retransmit', 'ack-timeout', and 'ack- 'missing-hb-allowed', 'max-retransmit', 'ack-timeout', and 'ack-
random-factor', if present, do not need to be provided for both random-factor', if present, do not need to be provided for both
'mitigating-config', and 'idle-config' in a PUT request. 'mitigating-config', and 'idle-config' in a PUT request.
The PUT request with a higher numeric 'sid' value overrides the DOTS The PUT request with a higher numeric 'sid' value overrides the DOTS
signal channel session configuration data installed by a PUT request signal channel session configuration data installed by a PUT request
with a lower numeric 'sid' value. To avoid maintaining a long list with a lower numeric 'sid' value. To avoid maintaining a long list
of 'sid' requests from a DOTS client, the lower numeric 'sid' MUST be of 'sid' requests from a DOTS client, the lower numeric 'sid' MUST be
automatically deleted and no longer available at the DOTS server. automatically deleted and no longer available at the DOTS server.
Figure 20 shows a PUT request example to convey the configuration Figure 22 shows a PUT request example to convey the configuration
parameters for the DOTS signal channel. In this example, the parameters for the DOTS signal channel. In this example, the
heartbeat mechanism is disabled when no mitigation is active, while heartbeat mechanism is disabled when no mitigation is active, while
the heartbeat interval is set to '91' when a mitigation is active. the heartbeat interval is set to '91' when a mitigation is active.
Header: PUT (Code=0.03) Header: PUT (Code=0.03)
Uri-Path: ".well-known" Uri-Path: ".well-known"
Uri-Path: "dots" Uri-Path: "dots"
Uri-Path: "config" Uri-Path: "config"
Uri-Path: "sid=123" Uri-Path: "sid=123"
Content-Format: "application/dots+cbor" Content-Format: "application/dots+cbor"
skipping to change at page 48, line 24 skipping to change at page 48, line 24
"heartbeat-interval": { "heartbeat-interval": {
"current-value": 91 "current-value": 91
}, },
"missing-hb-allowed": { "missing-hb-allowed": {
"current-value": 3 "current-value": 3
}, },
"max-retransmit": { "max-retransmit": {
"current-value": 3 "current-value": 3
}, },
"ack-timeout": { "ack-timeout": {
"current-value-decimal": "2.0" "current-value-decimal": "2.00"
}, },
"ack-random-factor": { "ack-random-factor": {
"current-value-decimal": "1.5" "current-value-decimal": "1.50"
} }
}, },
"idle-config": { "idle-config": {
"heartbeat-interval": { "heartbeat-interval": {
"current-value": 0 "current-value": 0
}, },
"max-retransmit": { "max-retransmit": {
"current-value": 3 "current-value": 3
}, },
"ack-timeout": { "ack-timeout": {
"current-value-decimal": "2.0" "current-value-decimal": "2.00"
}, },
"ack-random-factor": { "ack-random-factor": {
"current-value-decimal": "1.5" "current-value-decimal": "1.50"
} }
} }
} }
} }
Figure 20: PUT to Convey the Configuration Parameters Figure 22: PUT to Convey the Configuration Parameters
The DOTS server indicates the result of processing the PUT request The DOTS server indicates the result of processing the PUT request
using CoAP response codes: using CoAP response codes:
o If the request is missing a mandatory attribute, does not include o If the request is missing a mandatory attribute, does not include
a 'sid' Uri-Path, or contains one or more invalid or unknown a 'sid' Uri-Path, or contains one or more invalid or unknown
parameters, 4.00 (Bad Request) MUST be returned in the response. parameters, 4.00 (Bad Request) MUST be returned in the response.
o If the DOTS server does not find the 'sid' parameter value o If the DOTS server does not find the 'sid' parameter value
conveyed in the PUT request in its configuration data and if the conveyed in the PUT request in its configuration data and if the
skipping to change at page 49, line 23 skipping to change at page 49, line 23
o If the DOTS server finds the 'sid' parameter value conveyed in the o If the DOTS server finds the 'sid' parameter value conveyed in the
PUT request in its configuration data and if the DOTS server has PUT request in its configuration data and if the DOTS server has
accepted the updated configuration parameters, 2.04 (Changed) MUST accepted the updated configuration parameters, 2.04 (Changed) MUST
be returned in the response. be returned in the response.
o If any of the 'heartbeat-interval', 'missing-hb-allowed', 'max- o If any of the 'heartbeat-interval', 'missing-hb-allowed', 'max-
retransmit', 'target-protocol', 'ack-timeout', and 'ack-random- retransmit', 'target-protocol', 'ack-timeout', and 'ack-random-
factor' attribute values are not acceptable to the DOTS server, factor' attribute values are not acceptable to the DOTS server,
4.22 (Unprocessable Entity) MUST be returned in the response. 4.22 (Unprocessable Entity) MUST be returned in the response.
Upon receipt of this error code, the DOTS client SHOULD request Upon receipt of this error code, the DOTS client SHOULD retrieve
the maximum and minimum attribute values acceptable to the DOTS the maximum and minimum attribute values acceptable to the DOTS
server (Section 4.5.1). server (Section 4.5.1).
The DOTS client may re-try and send the PUT request with updated The DOTS client may re-try and send the PUT request with updated
attribute values acceptable to the DOTS server. attribute values acceptable to the DOTS server.
A DOTS client may issue a GET message with 'sid' Uri-Path parameter A DOTS client may issue a GET message with 'sid' Uri-Path parameter
to retrieve the negotiated configuration. The response does not need to retrieve the negotiated configuration. The response does not need
to include 'sid' in its message body. to include 'sid' in its message body.
skipping to change at page 50, line 21 skipping to change at page 50, line 21
60 seconds (Section 5.10.5 of [RFC7252]). To prevent such overload, 60 seconds (Section 5.10.5 of [RFC7252]). To prevent such overload,
it is RECOMMENDED that DOTS servers return a Max-Age Option in GET it is RECOMMENDED that DOTS servers return a Max-Age Option in GET
responses. Considerations related to which value to use and how such responses. Considerations related to which value to use and how such
value is set, are implementation- and deployment-specific. value is set, are implementation- and deployment-specific.
If an Observe Option set to 0 is included in the configuration If an Observe Option set to 0 is included in the configuration
request, the DOTS server sends notifications of any configuration request, the DOTS server sends notifications of any configuration
change (Section 4.2 of [RFC7641]). change (Section 4.2 of [RFC7641]).
If a DOTS server detects that a misbehaving DOTS client does not If a DOTS server detects that a misbehaving DOTS client does not
contact the DOTS server after the expiry of Max-Age, in order to contact the DOTS server after the expiry of Max-Age and retrieve the
retrieve the signal channel configuration data, it MAY terminate the signal channel configuration data, it MAY terminate the (D)TLS
(D)TLS session. A (D)TLS session is terminated by the receipt of an session. A (D)TLS session is terminated by the receipt of an
authenticated message that closes the connection (e.g., a fatal alert authenticated message that closes the connection (e.g., a fatal alert
(Section 6 of [RFC8446])). (Section 6 of [RFC8446])).
4.5.4. Delete DOTS Signal Channel Session Configuration 4.5.4. Delete DOTS Signal Channel Session Configuration
A DELETE request is used to delete the installed DOTS signal channel A DELETE request is used to delete the installed DOTS signal channel
session configuration data (Figure 21). session configuration data (Figure 23).
Header: DELETE (Code=0.04) Header: DELETE (Code=0.04)
Uri-Path: ".well-known" Uri-Path: ".well-known"
Uri-Path: "dots" Uri-Path: "dots"
Uri-Path: "config" Uri-Path: "config"
Uri-Path: "sid=123" Uri-Path: "sid=123"
Figure 21: Delete Configuration Figure 23: Delete Configuration
The DOTS server resets the DOTS signal channel session configuration The DOTS server resets the DOTS signal channel session configuration
back to the default values and acknowledges a DOTS client's request back to the default values and acknowledges a DOTS client's request
to remove the DOTS signal channel session configuration using 2.02 to remove the DOTS signal channel session configuration using 2.02
(Deleted) response code. (Deleted) response code.
Upon bootstrapping or reboot, a DOTS client MAY send a DELETE request Upon bootstrapping or reboot, a DOTS client MAY send a DELETE request
to set the configuration parameters to default values. Such a to set the configuration parameters to default values. Such a
request does not include any 'sid'. request does not include any 'sid'.
skipping to change at page 51, line 21 skipping to change at page 51, line 21
DOTS server for a signal session, then the response code 5.03 DOTS server for a signal session, then the response code 5.03
(Service Unavailable) will be returned in the response to the DOTS (Service Unavailable) will be returned in the response to the DOTS
client. client.
The DOTS server can return the error response code 5.03 in response The DOTS server can return the error response code 5.03 in response
to a request from the DOTS client or convey the error response code to a request from the DOTS client or convey the error response code
5.03 in a unidirectional notification response from the DOTS server. 5.03 in a unidirectional notification response from the DOTS server.
The DOTS server in the error response conveys the alternate DOTS The DOTS server in the error response conveys the alternate DOTS
server's FQDN, and the alternate DOTS server's IP address(es) values server's FQDN, and the alternate DOTS server's IP address(es) values
in the CBOR body (Figure 22). in the CBOR body (Figure 24).
{ {
"ietf-dots-signal-channel:redirected-signal": { "ietf-dots-signal-channel:redirected-signal": {
"alt-server": "string", "alt-server": "string",
"alt-server-record": [ "alt-server-record": [
"string" "string"
] ]
} }
Figure 22: Redirected Server Error Response Body Figure 24: Redirected Server Error Response Body Schema
The parameters are described below: The parameters are described below:
alt-server: FQDN of an alternate DOTS server. alt-server: FQDN of an alternate DOTS server.
This is a mandatory attribute. This is a mandatory attribute.
alt-server-record: A list of IP addresses of an alternate DOTS alt-server-record: A list of IP addresses of an alternate DOTS
server. server.
skipping to change at page 52, line 20 skipping to change at page 52, line 20
If the alternate DOTS server TTL has expired, the DOTS client MUST If the alternate DOTS server TTL has expired, the DOTS client MUST
use the DOTS server(s), that was provisioned using means discussed in use the DOTS server(s), that was provisioned using means discussed in
Section 4.1. This fall back mechanism is triggered immediately upon Section 4.1. This fall back mechanism is triggered immediately upon
expiry of the TTL, except when a DDoS attack is active. expiry of the TTL, except when a DDoS attack is active.
Requests issued by misbehaving DOTS clients which do not honor the Requests issued by misbehaving DOTS clients which do not honor the
TTL conveyed in the Max-Age Option or react to explicit re-direct TTL conveyed in the Max-Age Option or react to explicit re-direct
messages can be rejected by DOTS servers. messages can be rejected by DOTS servers.
Figure 23 shows a 5.03 response example to convey the DOTS alternate Figure 25 shows a 5.03 response example to convey the DOTS alternate
server 'alt-server.example' together with its IP addresses server 'alt-server.example' together with its IP addresses
2001:db8:6401::1 and 2001:db8:6401::2. 2001:db8:6401::1 and 2001:db8:6401::2.
{ {
"ietf-dots-signal-channel:redirected-signal": { "ietf-dots-signal-channel:redirected-signal": {
"alt-server": "alt-server.example", "alt-server": "alt-server.example",
"alt-server-record": [ "alt-server-record": [
"2001:db8:6401::1", "2001:db8:6401::1",
"2001:db8:6401::2" "2001:db8:6401::2"
] ]
} }
Figure 23: Example of Redirected Server Error Response Body Figure 25: Example of Redirected Server Error Response Body
When the DOTS client receives 5.03 response with an alternate server When the DOTS client receives 5.03 response with an alternate server
included, it considers the current request as failed, but SHOULD try included, it considers the current request as failed, but SHOULD try
re-sending the request to the alternate DOTS server. During a DDoS re-sending the request to the alternate DOTS server. During a DDoS
attack, the DNS server may be the target of another DDoS attack, attack, the DNS server may be the target of another DDoS attack,
alternate DOTS server's IP addresses conveyed in the 5.03 response alternate DOTS server's IP addresses conveyed in the 5.03 response
help the DOTS client skip DNS lookup of the alternate DOTS server. help the DOTS client skip DNS lookup of the alternate DOTS server, at
The DOTS client can then try to establish a UDP or a TCP session with the cost of trusting the first DOTS server to provide accurate
the alternate DOTS server. The DOTS client MAY implement a method to information. The DOTS client can then try to establish a UDP or a
construct IPv4-embedded IPv6 addresses [RFC6052]; this is required to TCP session with the alternate DOTS server. The DOTS client MAY
handle the scenario where an IPv6-only DOTS client communicates with implement a method to construct IPv4-embedded IPv6 addresses
an IPv4-only alternate DOTS server. [RFC6052]; this is required to handle the scenario where an IPv6-only
DOTS client communicates with an IPv4-only alternate DOTS server.
If the DOTS client has been redirected to a DOTS server to which it If the DOTS client has been redirected to a DOTS server to which it
has already communicated with within the last five (5) minutes, it has already communicated with within the last five (5) minutes, it
MUST ignore the redirection and try to contact other DOTS servers MUST ignore the redirection and try to contact other DOTS servers
listed in the local configuration or discovered using dynamic means listed in the local configuration or discovered using dynamic means
such as DHCP or SRV procedures. It is RECOMMENDED that DOTS clients such as DHCP or SRV procedures. It is RECOMMENDED that DOTS clients
support means to alert administrators about redirect loops. support means to alert administrators about redirect loops.
4.7. Heartbeat Mechanism 4.7. Heartbeat Mechanism
To provide an indication of signal health and distinguish an 'idle' To provide an indication of signal health and distinguish an 'idle'
signal channel from a 'disconnected' or 'defunct' session, the DOTS signal channel from a 'disconnected' or 'defunct' session, the DOTS
agent sends a heartbeat over the signal channel to maintain its half agent sends a heartbeat over the signal channel to maintain its half
of the channel. The DOTS agent similarly expects a heartbeat from of the channel. The DOTS agent similarly expects a heartbeat from
its peer DOTS agent, and may consider a session terminated in the its peer DOTS agent, and may consider a session terminated in the
prolonged absence of a peer agent heartbeat. prolonged absence of a peer agent heartbeat. Concretely, while the
communication between the DOTS agents is otherwise quiescent, the
While the communication between the DOTS agents is quiescent, the
DOTS client will probe the DOTS server to ensure it has maintained DOTS client will probe the DOTS server to ensure it has maintained
cryptographic state and vice versa. Such probes can also keep cryptographic state and vice versa. Such probes can also keep
firewalls and/or stateful translators bindings alive. This probing firewalls and/or stateful translators bindings alive. This probing
reduces the frequency of establishing a new handshake when a DOTS reduces the frequency of establishing a new handshake when a DOTS
signal needs to be conveyed to the DOTS server. signal needs to be conveyed to the DOTS server.
DOTS servers MAY trigger their heartbeat requests immediately after DOTS servers MAY trigger their heartbeat requests immediately after
receiving heartbeat probes from peer DOTS clients. As a reminder, it receiving heartbeat probes from peer DOTS clients. As a reminder, it
is the responsibility of DOTS clients to ensure that on-path is the responsibility of DOTS clients to ensure that on-path
translators/firewalls are maintaining a binding so that the same translators/firewalls are maintaining a binding so that the same
skipping to change at page 54, line 19 skipping to change at page 54, line 23
client and after maximum 'missing-hb-allowed' threshold is client and after maximum 'missing-hb-allowed' threshold is
reached, the DOTS server concludes the session is disconnected. reached, the DOTS server concludes the session is disconnected.
In DOTS over UDP, heartbeat messages MUST be exchanged between the In DOTS over UDP, heartbeat messages MUST be exchanged between the
DOTS agents using the "CoAP Ping" mechanism defined in Section 4.2 of DOTS agents using the "CoAP Ping" mechanism defined in Section 4.2 of
[RFC7252]. Concretely, the DOTS agent sends an Empty Confirmable [RFC7252]. Concretely, the DOTS agent sends an Empty Confirmable
message and the peer DOTS agent will respond by sending a Reset message and the peer DOTS agent will respond by sending a Reset
message. message.
In DOTS over TCP, heartbeat messages MUST be exchanged between the In DOTS over TCP, heartbeat messages MUST be exchanged between the
DOTS agents using the Ping and Pong messages specified in Section 4.4 DOTS agents using the Ping and Pong messages specified in Section 5.4
of [RFC8323]. That is, the DOTS agent sends a Ping message and the of [RFC8323]. That is, the DOTS agent sends a Ping message and the
peer DOTS agent would respond by sending a single Pong message. peer DOTS agent would respond by sending a single Pong message.
5. DOTS Signal Channel YANG Modules 5. DOTS Signal Channel YANG Modules
This document defines a YANG [RFC7950] module for DOTS mitigation This document defines a YANG [RFC7950] module for DOTS mitigation
scope, DOTS signal channel session configuration data, and DOTS scope, DOTS signal channel session configuration data, and DOTS
redirected signalling. redirection signalling.
This YANG module (ietf-dots-signal-channel) defines the DOTS client This YANG module (ietf-dots-signal-channel) defines the DOTS client
interaction with the DOTS server as seen by the DOTS client. A DOTS interaction with the DOTS server as seen by the DOTS client. A DOTS
server is allowed to update the non-configurable 'ro' entities in the server is allowed to update the non-configurable 'ro' entities in the
responses. This YANG module is not intended to be used for DOTS responses. This YANG module is not intended to be used via NETCONF/
server management purposes. Such module is out of the scope of this RESTCONF for DOTS server management purposes; such module is out of
document. the scope of this document. It serves only to provide a data model
and encoding, but not a management data model.
A companion YANG module is defined to include a collection of types A companion YANG module is defined to include a collection of types
defined by IANA: "iana-dots-signal-channel" (Section 5.2). defined by IANA: "iana-dots-signal-channel" (Section 5.2).
5.1. Tree Structure 5.1. Tree Structure
This document defines the YANG module "ietf-dots-signal-channel" This document defines the YANG module "ietf-dots-signal-channel"
(Section 5.3), which has the following tree structure. A DOTS signal (Section 5.3), which has the following tree structure. A DOTS signal
message can either be a mitigation or a configuration message. message can either be a mitigation or a configuration message.
module: ietf-dots-signal-channel module: ietf-dots-signal-channel
+--rw dots-signal +--rw dots-signal
+--rw (message-type)? +--rw (message-type)?
+--:(mitigation-scope) +--:(mitigation-scope)
| +--rw scope* [cuid mid] | +--rw scope* [cuid mid]
| +--rw cdid? string | +--rw cdid? string
| +--rw cuid string | +--rw cuid string
| +--rw mid uint32 | +--rw mid uint32
| +--rw target-prefix* inet:ip-prefix | +--rw target-prefix* inet:ip-prefix
| +--rw target-port-range* [lower-port upper-port] | +--rw target-port-range* [lower-port]
| | +--rw lower-port inet:port-number | | +--rw lower-port inet:port-number
| | +--rw upper-port inet:port-number | | +--rw upper-port? inet:port-number
| +--rw target-protocol* uint8 | +--rw target-protocol* uint8
| +--rw target-fqdn* inet:domain-name | +--rw target-fqdn* inet:domain-name
| +--rw target-uri* inet:uri | +--rw target-uri* inet:uri
| +--rw alias-name* string | +--rw alias-name* string
| +--rw lifetime? int32 | +--rw lifetime? int32
| +--rw trigger-mitigation? boolean | +--rw trigger-mitigation? boolean
| +--ro mitigation-start? uint64 | +--ro mitigation-start? uint64
| +--ro status? iana-signal:status | +--ro status? iana-signal:status
| +--ro conflict-information | +--ro conflict-information
| | +--ro conflict-status? iana-signal:conflict-status | | +--ro conflict-status? iana-signal:conflict-status
| | +--ro conflict-cause? iana-signal:conflict-cause | | +--ro conflict-cause? iana-signal:conflict-cause
| | +--ro retry-timer? uint32 | | +--ro retry-timer? uint32
| | +--ro conflict-scope | | +--ro conflict-scope
| | +--ro target-prefix* inet:ip-prefix | | +--ro target-prefix* inet:ip-prefix
| | +--ro target-port-range* [lower-port upper-port] | | +--ro target-port-range* [lower-port]
| | | +--ro lower-port inet:port-number | | | +--ro lower-port inet:port-number
| | | +--ro upper-port inet:port-number | | | +--ro upper-port? inet:port-number
| | +--ro target-protocol* uint8 | | +--ro target-protocol* uint8
| | +--ro target-fqdn* inet:domain-name | | +--ro target-fqdn* inet:domain-name
| | +--ro target-uri* inet:uri | | +--ro target-uri* inet:uri
| | +--ro alias-name* string | | +--ro alias-name* string
| | +--ro acl-list* [acl-name] | | +--ro acl-list* [acl-name]
| | | +--ro acl-name | | | +--ro acl-name
| | | | -> /ietf-data:dots-data/dots-client/acls/ | | | | -> /ietf-data:dots-data/dots-client/acls/
| | | | acl/name | | | | acl/name
| | | +--ro acl-type? | | | +--ro acl-type?
| | | -> /ietf-data:dots-data/dots-client/acls/ | | | -> /ietf-data:dots-data/dots-client/acls/
skipping to change at page 56, line 45 skipping to change at page 56, line 49
| +--rw ack-random-factor | +--rw ack-random-factor
| +--ro max-value-decimal? decimal64 | +--ro max-value-decimal? decimal64
| +--ro min-value-decimal? decimal64 | +--ro min-value-decimal? decimal64
| +--rw current-value-decimal? decimal64 | +--rw current-value-decimal? decimal64
+--:(redirected-signal) +--:(redirected-signal)
+--ro alt-server string +--ro alt-server string
+--ro alt-server-record* inet:ip-address +--ro alt-server-record* inet:ip-address
5.2. IANA DOTS Signal Channel YANG Module 5.2. IANA DOTS Signal Channel YANG Module
<CODE BEGINS> file "iana-dots-signal-channel@2018-10-17.yang" <CODE BEGINS> file "iana-dots-signal-channel@2019-01-17.yang"
module iana-dots-signal-channel { module iana-dots-signal-channel {
yang-version 1.1; yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:iana-dots-signal-channel"; namespace "urn:ietf:params:xml:ns:yang:iana-dots-signal-channel";
prefix iana-signal; prefix iana-signal;
organization organization
"IANA"; "IANA";
contact contact
"Internet Assigned Numbers Authority "Internet Assigned Numbers Authority
Postal: ICANN Postal: ICANN
12025 Waterfront Drive, Suite 300 12025 Waterfront Drive, Suite 300
Los Angeles, CA 90094-2536 Los Angeles, CA 90094-2536
United States of America United States of America
Tel: +1 310 301 5800 Tel: +1 310 301 5800
<mailto:iana@iana.org>"; <mailto:iana@iana.org>";
description description
"This module contains a collection of YANG data types defined "This module contains a collection of YANG data types defined
by IANA and used for DOTS signal channel protocol. by IANA and used for DOTS signal channel protocol.
Copyright (c) 2018 IETF Trust and the persons identified as Copyright (c) 2019 IETF Trust and the persons identified as
authors of the code. All rights reserved. authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with or Redistribution and use in source and binary forms, with or
without modification, is permitted pursuant to, and subject without modification, is permitted pursuant to, and subject
to the license terms contained in, the Simplified BSD License to the license terms contained in, the Simplified BSD License
set forth in Section 4.c of the IETF Trust's Legal Provisions set forth in Section 4.c of the IETF Trust's Legal Provisions
Relating to IETF Documents Relating to IETF Documents
(http://trustee.ietf.org/license-info). (http://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC XXXX; see This version of this YANG module is part of RFC XXXX; see
the RFC itself for full legal notices."; the RFC itself for full legal notices.";
revision 2018-10-17 { revision 2019-01-17 {
description description
"Initial revision."; "Initial revision.";
reference reference
"RFC XXXX: Distributed Denial-of-Service Open Threat "RFC XXXX: Distributed Denial-of-Service Open Threat
Signaling (DOTS) Signal Channel Specification"; Signaling (DOTS) Signal Channel Specification";
} }
typedef status { typedef status {
type enumeration { type enumeration {
enum attack-mitigation-in-progress { enum attack-mitigation-in-progress {
skipping to change at page 60, line 37 skipping to change at page 60, line 41
"Enumeration for attack status codes."; "Enumeration for attack status codes.";
} }
} }
<CODE ENDS> <CODE ENDS>
5.3. IETF DOTS Signal Channel YANG Module 5.3. IETF DOTS Signal Channel YANG Module
This module uses the common YANG types defined in [RFC6991] and types This module uses the common YANG types defined in [RFC6991] and types
defined in [I-D.ietf-dots-data-channel]. defined in [I-D.ietf-dots-data-channel].
<CODE BEGINS> file "ietf-dots-signal-channel@2018-10-17.yang" <CODE BEGINS> file "ietf-dots-signal-channel@2019-01-17.yang"
module ietf-dots-signal-channel { module ietf-dots-signal-channel {
yang-version 1.1; yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-dots-signal-channel"; namespace "urn:ietf:params:xml:ns:yang:ietf-dots-signal-channel";
prefix signal; prefix signal;
import ietf-inet-types { import ietf-inet-types {
prefix inet; prefix inet;
reference "Section 4 of RFC 6991"; reference "Section 4 of RFC 6991";
} }
import ietf-yang-types { import ietf-yang-types {
skipping to change at page 61, line 37 skipping to change at page 61, line 41
Author: Andrew Mortensen Author: Andrew Mortensen
<mailto:amortensen@arbor.net> <mailto:amortensen@arbor.net>
Author: Nik Teague Author: Nik Teague
<mailto:nteague@verisign.com>"; <mailto:nteague@verisign.com>";
description description
"This module contains YANG definition for the signaling "This module contains YANG definition for the signaling
messages exchanged between a DOTS client and a DOTS server. messages exchanged between a DOTS client and a DOTS server.
Copyright (c) 2018 IETF Trust and the persons identified as Copyright (c) 2019 IETF Trust and the persons identified as
authors of the code. All rights reserved. authors of the code. All rights reserved.
Redistribution and use in source and binary forms, with or Redistribution and use in source and binary forms, with or
without modification, is permitted pursuant to, and subject without modification, is permitted pursuant to, and subject
to the license terms contained in, the Simplified BSD License to the license terms contained in, the Simplified BSD License
set forth in Section 4.c of the IETF Trust's Legal Provisions set forth in Section 4.c of the IETF Trust's Legal Provisions
Relating to IETF Documents Relating to IETF Documents
(http://trustee.ietf.org/license-info). (http://trustee.ietf.org/license-info).
This version of this YANG module is part of RFC XXXX; see This version of this YANG module is part of RFC XXXX; see
the RFC itself for full legal notices."; the RFC itself for full legal notices.";
revision 2018-10-17 { revision 2019-01-17 {
description description
"Initial revision."; "Initial revision.";
reference reference
"RFC XXXX: Distributed Denial-of-Service Open Threat "RFC XXXX: Distributed Denial-of-Service Open Threat
Signaling (DOTS) Signal Channel Specification"; Signaling (DOTS) Signal Channel Specification";
} }
/* /*
* Groupings * Groupings
*/ */
skipping to change at page 62, line 37 skipping to change at page 62, line 41
gateway's client-facing-side to the gateway's gateway's client-facing-side to the gateway's
server-facing-side, and from the gateway's server-facing-side, and from the gateway's
server-facing-side to the DOTS server. server-facing-side to the DOTS server.
It may be used by the final DOTS server It may be used by the final DOTS server
for policy enforcement purposes."; for policy enforcement purposes.";
} }
leaf cuid { leaf cuid {
type string; type string;
description description
"A unique identifier that is randomly "A unique identifier that is
generated by a DOTS client to prevent generated by a DOTS client to prevent
request collisions. It is expected that the request collisions. It is expected that the
cuid will remain consistent throughout the cuid will remain consistent throughout the
lifetime of the DOTS client."; lifetime of the DOTS client.";
} }
leaf mid { leaf mid {
type uint32; type uint32;
description description
"Mitigation request identifier. "Mitigation request identifier.
skipping to change at page 70, line 40 skipping to change at page 70, line 44
uses signal-config; uses signal-config;
} }
case redirected-signal { case redirected-signal {
description description
"Redirected signaling."; "Redirected signaling.";
uses redirected-signal; uses redirected-signal;
} }
} }
} }
} }
<CODE ENDS> <CODE ENDS>
6. Mapping Parameters to CBOR 6. YANG/JSON Mapping Parameters to CBOR
All parameters in the payload of the DOTS signal channel MUST be All parameters in the payload of the DOTS signal channel MUST be
mapped to CBOR types as shown in Table 4 and are assigned an integer mapped to CBOR types as shown in Table 4 and are assigned an integer
key to save space. The CBOR key values are divided into two types: key to save space. The CBOR key values are divided into two types:
comprehension-required and comprehension-optional. DOTS agents can comprehension-required and comprehension-optional. DOTS agents can
safely ignore comprehension-optional values they don't understand, safely ignore comprehension-optional values they don't understand,
but cannot successfully process a request if it contains but cannot successfully process a request if it contains
comprehension-required values that are not understood. The 4.00 comprehension-required values that are not understood. The 4.00
response SHOULD include a diagnostic payload describing the unknown response SHOULD include a diagnostic payload describing the unknown
comprehension-required CBOR key values. The initial set of CBOR key comprehension-required CBOR key values. The initial set of CBOR key
skipping to change at page 72, line 43 skipping to change at page 72, line 46
| trigger-mitigation | boolean | 45 | 7 bits 20 | False | | trigger-mitigation | boolean | 45 | 7 bits 20 | False |
| | | | 7 bits 21 | True | | | | | 7 bits 21 | True |
| ietf-dots-signal-cha | | | | | | ietf-dots-signal-cha | | | | |
|nnel:redirected-signal| container | 46 | 5 map | Object | |nnel:redirected-signal| container | 46 | 5 map | Object |
| alt-server | string | 47 | 3 text string | String | | alt-server | string | 47 | 3 text string | String |
| alt-server-record | leaf-list | 48 | 4 array | Array | | alt-server-record | leaf-list | 48 | 4 array | Array |
| | inet: | | | | | | inet: | | | |
| | ip-address | | 3 text string | String | | | ip-address | | 3 text string | String |
+----------------------+-------------+-----+---------------+--------+ +----------------------+-------------+-----+---------------+--------+
Table 4: CBOR Mappings Used in DOTS Signal Channel Messages Table 4: CBOR Key Values Used in DOTS Signal Channel Messages & Their
Mappings to JSON and YANG
7. (D)TLS Protocol Profile and Performance Considerations 7. (D)TLS Protocol Profile and Performance Considerations
7.1. (D)TLS Protocol Profile 7.1. (D)TLS Protocol Profile
This section defines the (D)TLS protocol profile of DOTS signal This section defines the (D)TLS protocol profile of DOTS signal
channel over (D)TLS and DOTS data channel over TLS. channel over (D)TLS and DOTS data channel over TLS.
There are known attacks on (D)TLS, such as man-in-the-middle and There are known attacks on (D)TLS, such as man-in-the-middle and
protocol downgrade attacks. These are general attacks on (D)TLS and, protocol downgrade attacks. These are general attacks on (D)TLS and,
as such, they are not specific to DOTS over (D)TLS; refer to the as such, they are not specific to DOTS over (D)TLS; refer to the
(D)TLS RFCs for discussion of these security issues. DOTS agents (D)TLS RFCs for discussion of these security issues. DOTS agents
MUST adhere to the (D)TLS implementation recommendations and security MUST adhere to the (D)TLS implementation recommendations and security
considerations of [RFC7525] except with respect to (D)TLS version. considerations of [RFC7525] except with respect to (D)TLS version.
Since DOTS signal channel encryption relies upon (D)TLS is virtually Since DOTS signal channel encryption relying upon (D)TLS is virtually
a green-field deployment, DOTS agents MUST implement only (D)TLS 1.2 a green-field deployment, DOTS agents MUST implement only (D)TLS 1.2
or later. or later.
When a DOTS client is configured with a domain name of the DOTS When a DOTS client is configured with a domain name of the DOTS
server, and connects to its configured DOTS server, the server may server, and connects to its configured DOTS server, the server may
present it with a PKIX certificate. In order to ensure proper present it with a PKIX certificate. In order to ensure proper
authentication, a DOTS client MUST verify the entire certification authentication, a DOTS client MUST verify the entire certification
path per [RFC5280]. The DOTS client additionally uses [RFC6125] path per [RFC5280]. The DOTS client additionally uses [RFC6125]
validation techniques to compare the domain name with the certificate validation techniques to compare the domain name with the certificate
provided. provided.
A key challenge to deploying DOTS is the provisioning of DOTS A key challenge to deploying DOTS is the provisioning of DOTS
clients, including the distribution of keying material to DOTS clients, including the distribution of keying material to DOTS
clients to enable the required mutual authentication of DOTS agents. clients to enable the required mutual authentication of DOTS agents.
EST defines a method of certificate enrollment by which domains Enrollment over Secure Transport (EST) [RFC7030] defines a method of
operating DOTS servers may provide DOTS clients with all the certificate enrollment by which domains operating DOTS servers may
necessary cryptographic keying material, including a private key and provide DOTS clients with all the necessary cryptographic keying
a certificate to authenticate themselves. One deployment option is material, including a private key and a certificate to authenticate
DOTS clients behave as EST clients for certificate enrollment from an themselves. One deployment option is DOTS clients behave as EST
EST server provisioned by the mitigation provider. This document clients for certificate enrollment from an EST server provisioned by
does not specify which EST mechanism the DOTS client uses to achieve the mitigation provider. This document does not specify which EST or
initial enrollment. other mechanism the DOTS client uses to achieve initial enrollment.
The Server Name Indication (SNI) extension [RFC6066] defines a The Server Name Indication (SNI) extension [RFC6066] defines a
mechanism for a client to tell a (D)TLS server the name of the server mechanism for a client to tell a (D)TLS server the name of the server
it wants to contact. This is a useful extension for hosting it wants to contact. This is a useful extension for hosting
environments where multiple virtual servers are reachable over a environments where multiple virtual servers are reachable over a
single IP address. The DOTS client may or may not know if it is single IP address. The DOTS client may or may not know if it is
interacting with a DOTS server in a virtual server hosting interacting with a DOTS server in a virtual server hosting
environment, so the DOTS client SHOULD include the DOTS server FQDN environment, so the DOTS client SHOULD include the DOTS server FQDN
in the SNI extension. in the SNI extension.
Implementations compliant with this profile MUST implement all of the Implementations compliant with this profile MUST implement all of the
following items: following items:
o DTLS record replay detection (Section 3.3 of [RFC6347]) to protect o DTLS record replay detection (Section 3.3 of [RFC6347]) or an
against replay attacks. equivalent mechanism to protect against replay attacks.
o DTLS session resumption without server-side state to resume o DTLS session resumption without server-side state to resume
session and convey the DOTS signal. session and convey the DOTS signal.
o Raw public keys [RFC7250] or PSK handshake [RFC4279] with (EC)DHE o At least one of raw public keys [RFC7250] or PSK handshake
key exchange which reduces the size of the ServerHello, and can be [RFC4279] with (EC)DHE key exchange which reduces the size of the
used by DOTS agents that cannot obtain certificates. ServerHello, and can be used by DOTS agents that cannot obtain
certificates.
Implementations compliant with this profile SHOULD implement all of Implementations compliant with this profile SHOULD implement all of
the following items to reduce the delay required to deliver a DOTS the following items to reduce the delay required to deliver a DOTS
signal channel message: signal channel message:
o TLS False Start [RFC7918] which reduces round-trips by allowing o TLS False Start [RFC7918] which reduces round-trips by allowing
the TLS second flight of messages (ChangeCipherSpec) to also the TLS client's second flight of messages (ChangeCipherSpec) to
contain the DOTS signal. also contain the DOTS signal.
o Cached Information Extension [RFC7924] which avoids transmitting o Cached Information Extension [RFC7924] which avoids transmitting
the server's certificate and certificate chain if the client has the server's certificate and certificate chain if the client has
cached that information from a previous TLS handshake. cached that information from a previous TLS handshake.
o TCP Fast Open [RFC7413] can reduce the number of round-trips to o TCP Fast Open [RFC7413] can reduce the number of round-trips to
convey DOTS signal channel message. convey DOTS signal channel message.
7.2. (D)TLS 1.3 Considerations 7.2. (D)TLS 1.3 Considerations
skipping to change at page 75, line 8 skipping to change at page 75, line 16
to convey the DOTS mitigation request message and, if there is no to convey the DOTS mitigation request message and, if there is no
response from the server after multiple retries, the DOTS client response from the server after multiple retries, the DOTS client
can resume the (D)TLS session in 0-RTT mode using PSK. can resume the (D)TLS session in 0-RTT mode using PSK.
Section 8 of [RFC8446] discusses some mechanisms to implement to Section 8 of [RFC8446] discusses some mechanisms to implement to
limit the impact of replay attacks on 0-RTT data. If the DOTS limit the impact of replay attacks on 0-RTT data. If the DOTS
server accepts 0-RTT, it MUST implement one of these mechanisms. server accepts 0-RTT, it MUST implement one of these mechanisms.
A DOTS server can reject 0-RTT by sending a TLS HelloRetryRequest. A DOTS server can reject 0-RTT by sending a TLS HelloRetryRequest.
A simplified TLS 1.3 handshake with 0-RTT DOTS mitigation request A simplified TLS 1.3 handshake with 0-RTT DOTS mitigation request
message exchange is shown in Figure 24. message exchange is shown in Figure 26.
DOTS Client DOTS Server DOTS Client DOTS Server
ClientHello ClientHello
(Finished) (0-RTT DOTS signal message)
(0-RTT DOTS signal message) -------->
(end_of_early_data) --------> ServerHello
ServerHello {EncryptedExtensions}
{EncryptedExtensions} {Finished}
{ServerConfiguration} <-------- [DOTS signal message]
{Certificate} (end_of_early_data)
{CertificateVerify} {Finished} -------->
{Finished} [DOTS signal message] <-------> [DOTS signal message]
<-------- [DOTS signal message]
{Finished} -------->
[DOTS signal message] <-------> [DOTS signal message] Note that:
() Indicates messages protected 0-RTT keys
{} Indicates messages protected using handshake keys
[] Indicates messages protected using 1-RTT keys
Figure 24: TLS 1.3 Handshake with 0-RTT Figure 26: A Simplified TLS 1.3 Handshake with 0-RTT
7.3. MTU and Fragmentation 7.3. DTLS MTU and Fragmentation
To avoid DOTS signal message fragmentation and the subsequent To avoid DOTS signal message fragmentation and the subsequent
decreased probability of message delivery, DOTS agents MUST ensure decreased probability of message delivery, DOTS agents MUST ensure
that the DTLS record MUST fit within a single datagram. If the path that the DTLS record MUST fit within a single datagram. If the path
MTU is not known to the DOTS server, an IP MTU of 1280 bytes SHOULD MTU is not known to the DOTS server, an IP MTU of 1280 bytes SHOULD
be assumed. If UDP is used to convey the DOTS signal messages then be assumed. The DOTS client must consider the amount of record
the DOTS client must consider the amount of record expansion expected expansion expected by the DTLS processing when calculating the size
by the DTLS processing when calculating the size of CoAP message that of CoAP message that fits within the path MTU. Path MTU MUST be
fits within the path MTU. Path MTU MUST be greater than or equal to greater than or equal to [CoAP message size + DTLS 1.2 overhead of 13
[CoAP message size + DTLS overhead of 13 octets + authentication octets + authentication overhead of the negotiated DTLS cipher suite
overhead of the negotiated DTLS cipher suite + block padding] + block padding] (Section 4.1.1.1 of [RFC6347]). If the total
(Section 4.1.1.1 of [RFC6347]). If the request size exceeds the path request size exceeds the path MTU then the DOTS client MUST split the
MTU then the DOTS client MUST split the DOTS signal into separate DOTS signal into separate messages; for example, the list of
messages, for example the list of addresses in the 'target-prefix' addresses in the 'target-prefix' parameter could be split into
parameter could be split into multiple lists and each list conveyed multiple lists and each list conveyed in a new PUT request.
in a new PUT request.
Implementation Note: DOTS choice of message size parameters works Implementation Note: DOTS choice of message size parameters works
well with IPv6 and with most of today's IPv4 paths. However, with well with IPv6 and with most of today's IPv4 paths. However, with
IPv4, it is harder to safely make sure that there is no IP IPv4, it is harder to safely make sure that there is no IP
fragmentation. If IPv4 path MTU is unknown, implementations may want fragmentation. If the IPv4 path MTU is unknown, implementations may
to limit themselves to more conservative IPv4 datagram sizes such as want to limit themselves to more conservative IPv4 datagram sizes
576 bytes, as per [RFC0791]. IP packets whose size does not exceed such as 576 bytes, as per [RFC0791]. IP packets whose size does not
576 bytes should never need to be fragmented: therefore, sending a exceed 576 bytes should never need to be fragmented: therefore,
maximum of 500 bytes of DOTS signal over a UDP datagram will sending a maximum of 500 bytes of DOTS signal over a UDP datagram
generally avoid IP fragmentation. will generally avoid IP fragmentation.
8. Mutual Authentication of DOTS Agents & Authorization of DOTS Clients 8. Mutual Authentication of DOTS Agents & Authorization of DOTS Clients
(D)TLS based upon client certificate can be used for mutual (D)TLS based upon client certificate can be used for mutual
authentication between DOTS agents. If a DOTS gateway is involved, authentication between DOTS agents. If, for example, a DOTS gateway
DOTS clients and DOTS gateways MUST perform mutual authentication; is involved, DOTS clients and DOTS gateways must perform mutual
only authorized DOTS clients are allowed to send DOTS signals to a authentication; only authorized DOTS clients are allowed to send DOTS
DOTS gateway. The DOTS gateway and the DOTS server MUST perform signals to a DOTS gateway. The DOTS gateway and the DOTS server must
mutual authentication; a DOTS server only allows DOTS signal channel perform mutual authentication; a DOTS server only allows DOTS signal
messages from an authorized DOTS gateway, thereby creating a two-link channel messages from an authorized DOTS gateway, thereby creating a
chain of transitive authentication between the DOTS client and the two-link chain of transitive authentication between the DOTS client
DOTS server. and the DOTS server.
The DOTS server SHOULD support certificate-based client The DOTS server should support certificate-based client
authentication. The DOTS client SHOULD respond to the DOTS server's authentication. The DOTS client should respond to the DOTS server's
TLS certificate request message with the PKIX certificate held by the TLS CertificateRequest message with the PKIX certificate held by the
DOTS client. DOTS client certificate validation MUST be performed as DOTS client. DOTS client certificate validation must be performed as
per [RFC5280] and the DOTS client certificate MUST conform to the per [RFC5280] and the DOTS client certificate must conform to the
[RFC5280] certificate profile. If a DOTS client does not support TLS [RFC5280] certificate profile. If a DOTS client does not support TLS
client certificate authentication, it MUST support pre-shared key client certificate authentication, it must support pre-shared key
based or raw public key based client authentication. based or raw public key based client authentication.
+-----------------------------------------------+ +-----------------------------------------------+
| example.com domain +---------+ | | example.com domain +---------+ |
| | AAA | | | | AAA | |
| +---------------+ | Server | | | +---------------+ | Server | |
| | Application | +------+--+ | | | Application | +------+--+ |
| | server +<-----------------+ ^ | | | server +<-----------------+ ^ |
| | (DOTS client) | | | | | | (DOTS client) | | | |
| +---------------+ | | | | +---------------+ | | |
skipping to change at page 77, line 28 skipping to change at page 77, line 28
| +--------------+ | | | | | | +--------------+ | | | | |
| +----+--------+ | +---------------+ | +----+--------+ | +---------------+
| ^ | | ^ |
| | | | | |
| +----------------+ | | | +----------------+ | |
| | DDoS detector | | | | | DDoS detector | | |
| | (DOTS client) +<---------------+ | | | (DOTS client) +<---------------+ |
| +----------------+ | | +----------------+ |
+-----------------------------------------------+ +-----------------------------------------------+
Figure 25: Example of Authentication and Authorization of DOTS Agents Figure 27: Example of Authentication and Authorization of DOTS Agents
In the example depicted in Figure 25, the DOTS gateway and DOTS In the example depicted in Figure 27, the DOTS gateway and DOTS
clients within the 'example.com' domain mutually authenticate. After clients within the 'example.com' domain mutually authenticate. After
the DOTS gateway validates the identity of a DOTS client, it the DOTS gateway validates the identity of a DOTS client, it
communicates with the AAA server in the 'example.com' domain to communicates with the AAA server in the 'example.com' domain to
determine if the DOTS client is authorized to request DDoS determine if the DOTS client is authorized to request DDoS
mitigation. If the DOTS client is not authorized, a 4.01 mitigation. If the DOTS client is not authorized, a 4.01
(Unauthorized) is returned in the response to the DOTS client. In (Unauthorized) is returned in the response to the DOTS client. In
this example, the DOTS gateway only allows the application server and this example, the DOTS gateway only allows the application server and
DDoS attack detector to request DDoS mitigation, but does not permit DDoS attack detector to request DDoS mitigation, but does not permit
the user of type 'guest' to request DDoS mitigation. the user of type 'guest' to request DDoS mitigation.
Also, DOTS gateways and servers located in different domains MUST Also, DOTS gateways and servers located in different domains must
perform mutual authentication (e.g., using certificates). A DOTS perform mutual authentication (e.g., using certificates). A DOTS
server will only allow a DOTS gateway with a certificate for a server will only allow a DOTS gateway with a certificate for a
particular domain to request mitigation for that domain. In particular domain to request mitigation for that domain. In
reference to Figure 25, the DOTS server only allows the DOTS gateway reference to Figure 27, the DOTS server only allows the DOTS gateway
to request mitigation for 'example.com' domain and not for other to request mitigation for 'example.com' domain and not for other
domains. domains.
9. IANA Considerations 9. IANA Considerations
This specification registers a service port (Section 9.1), a URI
suffix in the Well-Known URIs registry (Section 9.2), and two YANG
modules (Section 9.7). It also creates a new registry for DOTS
signal channel protocol (Section 9.6).
9.1. DOTS Signal Channel UDP and TCP Port Number 9.1. DOTS Signal Channel UDP and TCP Port Number
IANA is requested to assign the port number TBD to the DOTS signal IANA is requested to assign the port number TBD to the DOTS signal
channel protocol for both UDP and TCP from the "Service Name and channel protocol for both UDP and TCP from the "Service Name and
Transport Protocol Port Number Registry" available at Transport Protocol Port Number Registry" available at
https://www.iana.org/assignments/service-names-port-numbers/service- https://www.iana.org/assignments/service-names-port-numbers/service-
names-port-numbers.xhtml. names-port-numbers.xhtml.
The assignment of port number 4646 is strongly suggested, as 4646 is The assignment of port number 4646 is strongly suggested, as 4646 is
the ASCII decimal value for ".." (DOTS). the ASCII decimal value for ".." (DOTS).
skipping to change at page 78, line 41 skipping to change at page 78, line 36
| URI | Change | Specification | Related | | URI | Change | Specification | Related |
| suffix | controller | document(s) | information | | suffix | controller | document(s) | information |
+----------+----------------+---------------------+-----------------+ +----------+----------------+---------------------+-----------------+
| dots | IETF | [RFCXXXX] | None | | dots | IETF | [RFCXXXX] | None |
+----------+----------------+---------------------+-----------------+ +----------+----------------+---------------------+-----------------+
Table 5: 'dots' well-known URI Table 5: 'dots' well-known URI
9.3. Media Type Registration 9.3. Media Type Registration
This section registers the "application/dots+cbor" media type in the This document requests IANA to register the "application/dots+cbor"
"Media Types" registry [IANA.MediaTypes] in the manner described in media type in the "Media Types" registry [IANA.MediaTypes] in the
RFC 6838 [RFC6838], which can be used to indicate that the content is manner described in [RFC6838], which can be used to indicate that the
a DOTS signal channel object. content is a DOTS signal channel object:
9.3.1. Registry Contents
o Type name: application o Type name: application
o Subtype name: dots+cbor o Subtype name: dots+cbor
o Required parameters: N/A o Required parameters: N/A
o Optional parameters: N/A o Optional parameters: N/A
o Encoding considerations: binary o Encoding considerations: binary
o Security considerations: See the Security Considerations section o Security considerations: See the Security Considerations section
of [RFCXXXX] of [RFCXXXX]
o Interoperability considerations: N/A o Interoperability considerations: N/A
o Published specification: [RFCXXXX] o Published specification: [RFCXXXX]
skipping to change at page 79, line 20 skipping to change at page 79, line 13
o Fragment identifier considerations: N/A o Fragment identifier considerations: N/A
o Additional information: o Additional information:
Magic number(s): N/A Magic number(s): N/A
File extension(s): N/A File extension(s): N/A
Macintosh file type code(s): N/A Macintosh file type code(s): N/A
o Person & email address to contact for further information: o Person & email address to contact for further information:
IESG, iesg@ietf.org IESG, iesg@ietf.org
o Intended usage: COMMON o Intended usage: COMMON
o Restrictions on usage: none o Restrictions on usage: none
o Author: Tirumaleswar Reddy, kondtir@gmail.com o Author: See Authors' Addresses section.
o Change controller: IESG o Change controller: IESG
o Provisional registration? No o Provisional registration? No
9.4. CoAP Content-Formats Registration 9.4. CoAP Content-Formats Registration
This section registers the CoAP Content-Format ID for the This document requests IANA to register the CoAP Content-Format ID
"application/dots+cbor" media type in the "CoAP Content-Formats" for the "application/dots+cbor" media type in the "CoAP Content-
registry [IANA.CoAP.Content-Formats]. Formats" registry [IANA.CoAP.Content-Formats] (0-255 range):
9.4.1. Registry Contents
o Media Type: application/dots+cbor o Media Type: application/dots+cbor
o Encoding: - o Encoding: -
o Id: TBD o Id: TBD1
o Reference: [RFCXXXX] o Reference: [RFCXXXX]
9.5. CBOR Tag Registration 9.5. CBOR Tag Registration
This section defines the DOTS CBOR tag as another means for This section defines the DOTS CBOR tag as another means for
applications to declare that a CBOR data structure is a DOTS signal applications to declare that a CBOR data structure is a DOTS signal
channel object. Its use is optional and is intended for use in cases channel object. Its use is optional and is intended for use in cases
in which this information would not otherwise be known. DOTS CBOR in which this information would not otherwise be known. DOTS CBOR
tag is not required for DOTS signal channel protocol version tag is not required for DOTS signal channel protocol version
specified in this document. If present, the DOTS tag MUST prefix a specified in this document. If present, the DOTS tag MUST prefix a
DOTS signal channel object. DOTS signal channel object.
This section registers the DOTS signal channel CBOR tag in the "CBOR This document requests IANA to register the DOTS signal channel CBOR
Tags" registry [IANA.CBOR.Tags]. tag in the "CBOR Tags" registry [IANA.CBOR.Tags] using the 24-255
range:
9.5.1. Registry Contents
o CBOR Tag: TBD (please assign the same value as the Content-Format) o CBOR Tag: TBD2 (please assign the same value as the Content-
Format)
o Data Item: DDoS Open Threat Signaling (DOTS) signal channel object o Data Item: DDoS Open Threat Signaling (DOTS) signal channel object
o Semantics: DDoS Open Threat Signaling (DOTS) signal channel o Semantics: DDoS Open Threat Signaling (DOTS) signal channel
object, as defined in [RFCXXXX] object, as defined in [RFCXXXX]
o Description of Semantics: [RFCXXXX] o Description of Semantics: [RFCXXXX]
o Point of Contact: Tirumaleswar Reddy, kondtir@gmail.com
9.6. DOTS Signal Channel Protocol Registry 9.6. DOTS Signal Channel Protocol Registry
The document requests IANA to create a new registry, entitled "DOTS The document requests IANA to create a new registry, entitled "DOTS
Signal Channel Registry". The following sections creates new sub- Signal Channel Registry". The following sections define sub-
registries. registries.
9.6.1. DOTS Signal Channel CBOR Mappings Sub-Registry 9.6.1. DOTS Signal Channel CBOR Key Values Sub-Registry
The document requests IANA to create a new sub-registry, entitled The document requests IANA to create a new sub-registry, entitled
"DOTS Signal Channel CBOR Mappings". "DOTS Signal Channel CBOR Key Values".
The structure of this sub-registry is provided in Section 9.6.1.1. The structure of this sub-registry is provided in Section 9.6.1.1.
Registration requests are evaluated using the criteria described in Section 9.6.1.2 provides how the registry is initially populated with
the CBOR Key Value instructions in the registration template below the values in Table 4.
after a three-week review period on the dots-signal-reg-
review@ietf.org mailing list, on the advice of one or more Designated
Experts [RFC8126]. However, to allow for the allocation of values
prior to publication, the Designated Experts may approve registration
once they are satisfied that such a specification will be published.
[[ Note to the RFC Editor: The name of the mailing list should be
determined in consultation with the IESG and IANA. Suggested name:
dots-signal-reg-review@ietf.org. ]]
Registration requests sent to the mailing list for review should use
an appropriate subject (e.g., "Request to register parameter:
example"). Registration requests that are undetermined for a period
longer than 21 days can be brought to the IESG's attention (using the
iesg@ietf.org mailing list) for resolution.
Criteria that should be applied by the Designated Experts includes
determining whether the proposed registration duplicates existing
functionality, whether it is likely to be of general applicability or
whether it is useful only for a single application, and whether the
registration description is clear.
IANA must only accept registry updates from the Designated Experts
and should direct all requests for registration to the review mailing
list.
It is suggested that multiple Designated Experts be appointed who are
able to represent the perspectives of different applications using
this specification in order to enable broadly informed review of
registration decisions. In cases where a registration decision could
be perceived as creating a conflict of interest for a particular
Expert, that Expert should defer to the judgment of the other
Experts.
The registry is initially populated with the values in Table 6.
9.6.1.1. Registration Template 9.6.1.1. Registration Template
Parameter name: Parameter name:
Parameter name as used in the DOTS signal channel. Parameter name as used in the DOTS signal channel.
CBOR Key Value: CBOR Key Value:
Key value for the parameter. The key value MUST be an integer in Key value for the parameter. The key value MUST be an integer in
the 1-65535 range. The key values of the comprehension-required the 1-65535 range. The key values of the comprehension-required
range (0x0001 - 0x3FFF) and of the comprehension-optional range range (0x0001 - 0x3FFF) and of the comprehension-optional range
skipping to change at page 81, line 35 skipping to change at page 80, line 40
values of the comprehension-optional range (0x4000 - 0x7FFF) are values of the comprehension-optional range (0x4000 - 0x7FFF) are
assigned by Designated Expert [RFC8126] and of the comprehension- assigned by Designated Expert [RFC8126] and of the comprehension-
optional range (0xC000 - 0xFFFF) are reserved for Private Use optional range (0xC000 - 0xFFFF) are reserved for Private Use
[RFC8126]. [RFC8126].
CBOR Major Type: CBOR Major Type:
CBOR Major type and optional tag for the parameter. CBOR Major type and optional tag for the parameter.
Change Controller: Change Controller:
For Standards Track RFCs, list the "IESG". For others, give the For Standards Track RFCs, list the "IESG". For others, give the
name of the responsible party. Other details (e.g., postal name of the responsible party. Other details (e.g., email
address, email address, home page URI) may also be included. address) may also be included.
Specification Document(s): Specification Document(s):
Reference to the document or documents that specify the parameter, Reference to the document or documents that specify the parameter,
preferably including URIs that can be used to retrieve copies of preferably including URIs that can be used to retrieve copies of
the documents. An indication of the relevant sections may also be the documents. An indication of the relevant sections may also be
included but is not required. included but is not required.
9.6.1.2. Initial Sub-Registry Content 9.6.1.2. Initial Sub-Registry Content
+----------------------+-------+-------+------------+---------------+ +----------------------+-------+-------+------------+---------------+
skipping to change at page 83, line 8 skipping to change at page 82, line 17
| current-value- | 43 | 6tag4 | IESG | [RFCXXXX] | | current-value- | 43 | 6tag4 | IESG | [RFCXXXX] |
| decimal | | | | | | decimal | | | | |
| idle-config | 44 | 5 | IESG | [RFCXXXX] | | idle-config | 44 | 5 | IESG | [RFCXXXX] |
| trigger-mitigation | 45 | 7 | IESG | [RFCXXXX] | | trigger-mitigation | 45 | 7 | IESG | [RFCXXXX] |
| ietf-dots-signal-chan| 46 | 5 | IESG | [RFCXXXX] | | ietf-dots-signal-chan| 46 | 5 | IESG | [RFCXXXX] |
| nel:redirected-signal| | | | | | nel:redirected-signal| | | | |
| alt-server | 47 | 3 | IESG | [RFCXXXX] | | alt-server | 47 | 3 | IESG | [RFCXXXX] |
| alt-server-record | 48 | 4 | IESG | [RFCXXXX] | | alt-server-record | 48 | 4 | IESG | [RFCXXXX] |
+----------------------+-------+-------+------------+---------------+ +----------------------+-------+-------+------------+---------------+
Table 6: Initial DOTS Signal Channel CBOR Mappings Registry Table 6: Initial DOTS Signal Channel CBOR Key Values Registry
9.6.2. Status Codes Sub-Registry 9.6.2. Status Codes Sub-Registry
The document requests IANA to create a new sub-registry, entitled The document requests IANA to create a new sub-registry, entitled
"DOTS Signal Channel Status Codes". Codes in this registry are used "DOTS Signal Channel Status Codes". Codes in this registry are used
as valid values of 'status' parameter. as valid values of 'status' parameter.
The registry is initially populated with the following values: The registry is initially populated with the following values:
+-----+----------------------------------+--------------+-----------+ +-----+----------------------------------+--------------+-----------+
skipping to change at page 87, line 30 skipping to change at page 87, line 30
| | | mitigated. | | | | | mitigated. | |
+------+-------------------------------+----------------+-----------+ +------+-------------------------------+----------------+-----------+
New codes can be assigned via Standards Action [RFC8126]. New codes can be assigned via Standards Action [RFC8126].
9.7. DOTS Signal Channel YANG Modules 9.7. DOTS Signal Channel YANG Modules
This document requests IANA to register the following URIs in the This document requests IANA to register the following URIs in the
"ns" subregistry within the "IETF XML Registry" [RFC3688]: "ns" subregistry within the "IETF XML Registry" [RFC3688]:
URI: urn:ietf:params:xml:ns:yang:ietf-dots-signal-channel URI: urn:ietf:params:xml:ns:yang:ietf-dots-signal-channel
Registrant Contact: The IESG. Registrant Contact: The IESG.
XML: N/A; the requested URI is an XML namespace. XML: N/A; the requested URI is an XML namespace.
URI: urn:ietf:params:xml:ns:yang:iana-dots-signal-channel URI: urn:ietf:params:xml:ns:yang:iana-dots-signal-channel
Registrant Contact: IANA. Registrant Contact: IANA.
XML: N/A; the requested URI is an XML namespace. XML: N/A; the requested URI is an XML namespace.
This document requests IANA to register the following YANG modules in This document requests IANA to register the following YANG modules in
the "YANG Module Names" subregistry [RFC7950] within the "YANG the "YANG Module Names" subregistry [RFC7950] within the "YANG
Parameters" registry. Parameters" registry.
name: ietf-signal name: ietf-signal
namespace: urn:ietf:params:xml:ns:yang:ietf-dots-signal-channel namespace: urn:ietf:params:xml:ns:yang:ietf-dots-signal-channel
maintained by IANA: N
prefix: signal prefix: signal
reference: RFC XXXX reference: RFC XXXX
name: iana-signal name: iana-signal
namespace: urn:ietf:params:xml:ns:yang:iana-dots-signal-channel namespace: urn:ietf:params:xml:ns:yang:iana-dots-signal-channel
maintained by IANA: Y
prefix: iana-signal prefix: iana-signal
reference: RFC XXXX reference: RFC XXXX
This document defines the initial version of the IANA-maintained This document defines the initial version of the IANA-maintained
iana-dots-signal-channel YANG module. IANA is requested to add this iana-dots-signal-channel YANG module. IANA is requested to add this
note: note:
Status, conflict status, conflict cause, and attack status values Status, conflict status, conflict cause, and attack status values
must not be directly added to the iana-dots-signal-channel YANG must not be directly added to the iana-dots-signal-channel YANG
module. They must instead be respectively added to the "DOTS module. They must instead be respectively added to the "DOTS
skipping to change at page 88, line 46 skipping to change at page 88, line 46
IANA is requested to add this note to "DOTS Status Codes", "DOTS IANA is requested to add this note to "DOTS Status Codes", "DOTS
Conflict Status Codes", "DOTS Conflict Cause Codes", and "DOTS Attack Conflict Status Codes", "DOTS Conflict Cause Codes", and "DOTS Attack
Status Codes" registries: Status Codes" registries:
When this registry is modified, the YANG module iana-dots-signal- When this registry is modified, the YANG module iana-dots-signal-
channel must be updated as defined in [RFCXXXX]. channel must be updated as defined in [RFCXXXX].
10. Security Considerations 10. Security Considerations
High-level DOTS security considerations are documented in
[I-D.ietf-dots-requirements] and [I-D.ietf-dots-architecture].
Authenticated encryption MUST be used for data confidentiality and Authenticated encryption MUST be used for data confidentiality and
message integrity. The interaction between the DOTS agents requires message integrity. The interaction between the DOTS agents requires
Datagram Transport Layer Security (DTLS) and Transport Layer Security Datagram Transport Layer Security (DTLS) or Transport Layer Security
(TLS) with a cipher suite offering confidentiality protection and the (TLS) with a cipher suite offering confidentiality protection, and
guidance given in [RFC7525] MUST be followed to avoid attacks on the guidance given in [RFC7525] MUST be followed to avoid attacks on
(D)TLS. The (D)TLS protocol profile for DOTS signal channel is (D)TLS. The (D)TLS protocol profile used for the DOTS signal channel
specified in Section 7. is specified in Section 7.
If TCP is used between DOTS agents, an attacker may be able to inject If TCP is used between DOTS agents, an attacker may be able to inject
RST packets, bogus application segments, etc., regardless of whether RST packets, bogus application segments, etc., regardless of whether
TLS authentication is used. Because the application data is TLS TLS authentication is used. Because the application data is TLS
protected, this will not result in the application receiving bogus protected, this will not result in the application receiving bogus
data, but it will constitute a DoS on the connection. This attack data, but it will constitute a DoS on the connection. This attack
can be countered by using TCP-AO [RFC5925]. If TCP-AO is used, then can be countered by using TCP-AO [RFC5925]. If TCP-AO is used, then
any bogus packets injected by an attacker will be rejected by the any bogus packets injected by an attacker will be rejected by the
TCP-AO integrity check and therefore will never reach the TLS layer. TCP-AO integrity check and therefore will never reach the TLS layer.
An attack vector that can be achieved if the 'cuid' is guessable is a
misbehaving DOTS client from within the client's domain which uses
the 'cuid' of another DOTS client of the domain to delete or alter
active mitigations. For this attack vector to happen, the
misbehaving client needs to pass the security validation checks by
the DOTS server, and eventually the checks of a client-domain DOTS
gateway.
A similar attack can be achieved by a compromised DOTS client which
can sniff the TLS 1.2 handshake, use the client certificate to
identify the 'cuid' used by another DOTS client. This attack is not
possible with TLS 1.3 because most of the TLS handshake is encrypted
and the client certificate is not visible to eavesdroppers.
Rate-limiting DOTS requests, including those with new 'cuid' values, Rate-limiting DOTS requests, including those with new 'cuid' values,
from the same DOTS client defends against DoS attacks that would from the same DOTS client defends against DoS attacks that would
result in varying the 'cuid' to exhaust DOTS server resources. Rate- result in varying the 'cuid' to exhaust DOTS server resources. Rate-
limit policies SHOULD be enforced on DOTS gateways (if deployed) and limit policies SHOULD be enforced on DOTS gateways (if deployed) and
DOTS servers. DOTS servers.
In order to prevent leaking internal information outside a client- In order to prevent leaking internal information outside a client-
domain, DOTS gateways located in the client-domain SHOULD NOT reveal domain, DOTS gateways located in the client-domain SHOULD NOT reveal
the identification information that pertains to internal DOTS clients the identification information that pertains to internal DOTS clients
(e.g., source IP address, client's hostname) unless explicitly (e.g., source IP address, client's hostname) unless explicitly
skipping to change at page 90, line 17 skipping to change at page 90, line 37
12. Acknowledgements 12. Acknowledgements
Thanks to Christian Jacquenet, Roland Dobbins, Roman D. Danyliw, Thanks to Christian Jacquenet, Roland Dobbins, Roman D. Danyliw,
Michael Richardson, Ehud Doron, Kaname Nishizuka, Dave Dolson, Liang Michael Richardson, Ehud Doron, Kaname Nishizuka, Dave Dolson, Liang
Xia, Gilbert Clark, Xialiang Frank, Jim Schaad, Klaus Hartke and Xia, Gilbert Clark, Xialiang Frank, Jim Schaad, Klaus Hartke and
Nesredien Suleiman for the discussion and comments. Nesredien Suleiman for the discussion and comments.
Thanks to the core WG for the recommendations on Hop-Limit and Thanks to the core WG for the recommendations on Hop-Limit and
redirect signaling. redirect signaling.
Special thanks to Benjamin Kaduk for the detailed AD review.
13. References 13. References
13.1. Normative References 13.1. Normative References
[IANA.CBOR.Tags]
IANA, "Concise Binary Object Representation (CBOR) Tags",
<http://www.iana.org/assignments/cbor-tags/
cbor-tags.xhtml>.
[IANA.CoAP.Content-Formats]
IANA, "CoAP Content-Formats",
<http://www.iana.org/assignments/core-parameters/
core-parameters.xhtml#content-formats>.
[IANA.MediaTypes]
IANA, "Media Types",
<http://www.iana.org/assignments/media-types>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
DOI 10.17487/RFC3688, January 2004, DOI 10.17487/RFC3688, January 2004,
<https://www.rfc-editor.org/info/rfc3688>. <https://www.rfc-editor.org/info/rfc3688>.
[RFC4279] Eronen, P., Ed. and H. Tschofenig, Ed., "Pre-Shared Key [RFC4279] Eronen, P., Ed. and H. Tschofenig, Ed., "Pre-Shared Key
Ciphersuites for Transport Layer Security (TLS)", Ciphersuites for Transport Layer Security (TLS)",
RFC 4279, DOI 10.17487/RFC4279, December 2005, RFC 4279, DOI 10.17487/RFC4279, December 2005,
<https://www.rfc-editor.org/info/rfc4279>. <https://www.rfc-editor.org/info/rfc4279>.
[RFC4632] Fuller, V. and T. Li, "Classless Inter-domain Routing
(CIDR): The Internet Address Assignment and Aggregation
Plan", BCP 122, RFC 4632, DOI 10.17487/RFC4632, August
2006, <https://www.rfc-editor.org/info/rfc4632>.
[RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security
(TLS) Protocol Version 1.2", RFC 5246, (TLS) Protocol Version 1.2", RFC 5246,
DOI 10.17487/RFC5246, August 2008, DOI 10.17487/RFC5246, August 2008,
<https://www.rfc-editor.org/info/rfc5246>. <https://www.rfc-editor.org/info/rfc5246>.
[RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S., [RFC5280] Cooper, D., Santesson, S., Farrell, S., Boeyen, S.,
Housley, R., and W. Polk, "Internet X.509 Public Key Housley, R., and W. Polk, "Internet X.509 Public Key
Infrastructure Certificate and Certificate Revocation List Infrastructure Certificate and Certificate Revocation List
(CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008, (CRL) Profile", RFC 5280, DOI 10.17487/RFC5280, May 2008,
<https://www.rfc-editor.org/info/rfc5280>. <https://www.rfc-editor.org/info/rfc5280>.
skipping to change at page 92, line 20 skipping to change at page 92, line 35
[RFC7641] Hartke, K., "Observing Resources in the Constrained [RFC7641] Hartke, K., "Observing Resources in the Constrained
Application Protocol (CoAP)", RFC 7641, Application Protocol (CoAP)", RFC 7641,
DOI 10.17487/RFC7641, September 2015, DOI 10.17487/RFC7641, September 2015,
<https://www.rfc-editor.org/info/rfc7641>. <https://www.rfc-editor.org/info/rfc7641>.
[RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language", [RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
RFC 7950, DOI 10.17487/RFC7950, August 2016, RFC 7950, DOI 10.17487/RFC7950, August 2016,
<https://www.rfc-editor.org/info/rfc7950>. <https://www.rfc-editor.org/info/rfc7950>.
[RFC7951] Lhotka, L., "JSON Encoding of Data Modeled with YANG",
RFC 7951, DOI 10.17487/RFC7951, August 2016,
<https://www.rfc-editor.org/info/rfc7951>.
[RFC7959] Bormann, C. and Z. Shelby, Ed., "Block-Wise Transfers in [RFC7959] Bormann, C. and Z. Shelby, Ed., "Block-Wise Transfers in
the Constrained Application Protocol (CoAP)", RFC 7959, the Constrained Application Protocol (CoAP)", RFC 7959,
DOI 10.17487/RFC7959, August 2016, DOI 10.17487/RFC7959, August 2016,
<https://www.rfc-editor.org/info/rfc7959>. <https://www.rfc-editor.org/info/rfc7959>.
[RFC8085] Eggert, L., Fairhurst, G., and G. Shepherd, "UDP Usage [RFC8085] Eggert, L., Fairhurst, G., and G. Shepherd, "UDP Usage
Guidelines", BCP 145, RFC 8085, DOI 10.17487/RFC8085, Guidelines", BCP 145, RFC 8085, DOI 10.17487/RFC8085,
March 2017, <https://www.rfc-editor.org/info/rfc8085>. March 2017, <https://www.rfc-editor.org/info/rfc8085>.
[RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for [RFC8126] Cotton, M., Leiba, B., and T. Narten, "Guidelines for
skipping to change at page 93, line 5 skipping to change at page 93, line 21
Application Protocol) over TCP, TLS, and WebSockets", Application Protocol) over TCP, TLS, and WebSockets",
RFC 8323, DOI 10.17487/RFC8323, February 2018, RFC 8323, DOI 10.17487/RFC8323, February 2018,
<https://www.rfc-editor.org/info/rfc8323>. <https://www.rfc-editor.org/info/rfc8323>.
[RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol [RFC8446] Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018, Version 1.3", RFC 8446, DOI 10.17487/RFC8446, August 2018,
<https://www.rfc-editor.org/info/rfc8446>. <https://www.rfc-editor.org/info/rfc8446>.
13.2. Informative References 13.2. Informative References
[I-D.boucadair-dots-server-discovery]
Boucadair, M., K, R., and P. Patil, "Distributed-Denial-
of-Service Open Threat Signaling (DOTS) Server Discovery",
draft-boucadair-dots-server-discovery-05 (work in
progress), October 2018.
[I-D.ietf-core-comi] [I-D.ietf-core-comi]
Veillette, M., Stok, P., Pelov, A., and A. Bierman, "CoAP Veillette, M., Stok, P., Pelov, A., and A. Bierman, "CoAP
Management Interface", draft-ietf-core-comi-04 (work in Management Interface", draft-ietf-core-comi-04 (work in
progress), November 2018. progress), November 2018.
[I-D.ietf-core-hop-limit] [I-D.ietf-core-hop-limit]
Boucadair, M., K, R., and J. Shallow, "Constrained Boucadair, M., K, R., and J. Shallow, "Constrained
Application Protocol (CoAP) Hop Limit Option", draft-ietf- Application Protocol (CoAP) Hop Limit Option", draft-ietf-
core-hop-limit-02 (work in progress), December 2018. core-hop-limit-02 (work in progress), December 2018.
skipping to change at page 93, line 32 skipping to change at page 94, line 9
Mortensen, A., Andreasen, F., K, R., Teague, N., Compton, Mortensen, A., Andreasen, F., K, R., Teague, N., Compton,
R., and c. christopher_gray3@cable.comcast.com, R., and c. christopher_gray3@cable.comcast.com,
"Distributed-Denial-of-Service Open Threat Signaling "Distributed-Denial-of-Service Open Threat Signaling
(DOTS) Architecture", draft-ietf-dots-architecture-10 (DOTS) Architecture", draft-ietf-dots-architecture-10
(work in progress), December 2018. (work in progress), December 2018.
[I-D.ietf-dots-data-channel] [I-D.ietf-dots-data-channel]
Boucadair, M., K, R., Nishizuka, K., Xia, L., Patil, P., Boucadair, M., K, R., Nishizuka, K., Xia, L., Patil, P.,
Mortensen, A., and N. Teague, "Distributed Denial-of- Mortensen, A., and N. Teague, "Distributed Denial-of-
Service Open Threat Signaling (DOTS) Data Channel Service Open Threat Signaling (DOTS) Data Channel
Specification", draft-ietf-dots-data-channel-23 (work in Specification", draft-ietf-dots-data-channel-24 (work in
progress), November 2018. progress), December 2018.
[I-D.ietf-dots-requirements] [I-D.ietf-dots-requirements]
Mortensen, A., Moskowitz, R., and R. K, "Distributed Mortensen, A., Moskowitz, R., and R. K, "Distributed
Denial of Service (DDoS) Open Threat Signaling Denial of Service (DDoS) Open Threat Signaling
Requirements", draft-ietf-dots-requirements-16 (work in Requirements", draft-ietf-dots-requirements-16 (work in
progress), October 2018. progress), October 2018.
[I-D.ietf-dots-use-cases] [I-D.ietf-dots-use-cases]
Dobbins, R., Migault, D., Fouant, S., Moskowitz, R., Dobbins, R., Migault, D., Fouant, S., Moskowitz, R.,
Teague, N., Xia, L., and K. Nishizuka, "Use cases for DDoS Teague, N., Xia, L., and K. Nishizuka, "Use cases for DDoS
Open Threat Signaling", draft-ietf-dots-use-cases-16 (work Open Threat Signaling", draft-ietf-dots-use-cases-17 (work
in progress), July 2018. in progress), January 2019.
[I-D.ietf-tls-dtls13] [I-D.ietf-tls-dtls13]
Rescorla, E., Tschofenig, H., and N. Modadugu, "The Rescorla, E., Tschofenig, H., and N. Modadugu, "The
Datagram Transport Layer Security (DTLS) Protocol Version Datagram Transport Layer Security (DTLS) Protocol Version
1.3", draft-ietf-tls-dtls13-30 (work in progress), 1.3", draft-ietf-tls-dtls13-30 (work in progress),
November 2018. November 2018.
[IANA.CBOR.Tags]
IANA, "Concise Binary Object Representation (CBOR) Tags",
<http://www.iana.org/assignments/cbor-tags/
cbor-tags.xhtml>.
[IANA.CoAP.Content-Formats]
IANA, "CoAP Content-Formats",
<http://www.iana.org/assignments/core-parameters/
core-parameters.xhtml#content-formats>.
[IANA.MediaTypes]
IANA, "Media Types",
<http://www.iana.org/assignments/media-types>.
[proto_numbers] [proto_numbers]
"IANA, "Protocol Numbers"", 2011, "IANA, "Protocol Numbers"", 2011,
<http://www.iana.org/assignments/protocol-numbers>. <http://www.iana.org/assignments/protocol-numbers>.
[RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791, [RFC0791] Postel, J., "Internet Protocol", STD 5, RFC 791,
DOI 10.17487/RFC0791, September 1981, DOI 10.17487/RFC0791, September 1981,
<https://www.rfc-editor.org/info/rfc791>. <https://www.rfc-editor.org/info/rfc791>.
[RFC1983] Malkin, G., Ed., "Internet Users' Glossary", FYI 18,
RFC 1983, DOI 10.17487/RFC1983, August 1996,
<https://www.rfc-editor.org/info/rfc1983>.
[RFC3022] Srisuresh, P. and K. Egevang, "Traditional IP Network [RFC3022] Srisuresh, P. and K. Egevang, "Traditional IP Network
Address Translator (Traditional NAT)", RFC 3022, Address Translator (Traditional NAT)", RFC 3022,
DOI 10.17487/RFC3022, January 2001, DOI 10.17487/RFC3022, January 2001,
<https://www.rfc-editor.org/info/rfc3022>. <https://www.rfc-editor.org/info/rfc3022>.
[RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform [RFC3986] Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
Resource Identifier (URI): Generic Syntax", STD 66, Resource Identifier (URI): Generic Syntax", STD 66,
RFC 3986, DOI 10.17487/RFC3986, January 2005, RFC 3986, DOI 10.17487/RFC3986, January 2005,
<https://www.rfc-editor.org/info/rfc3986>. <https://www.rfc-editor.org/info/rfc3986>.
[RFC4122] Leach, P., Mealling, M., and R. Salz, "A Universally
Unique IDentifier (UUID) URN Namespace", RFC 4122,
DOI 10.17487/RFC4122, July 2005,
<https://www.rfc-editor.org/info/rfc4122>.
[RFC4340] Kohler, E., Handley, M., and S. Floyd, "Datagram [RFC4340] Kohler, E., Handley, M., and S. Floyd, "Datagram
Congestion Control Protocol (DCCP)", RFC 4340, Congestion Control Protocol (DCCP)", RFC 4340,
DOI 10.17487/RFC4340, March 2006, DOI 10.17487/RFC4340, March 2006,
<https://www.rfc-editor.org/info/rfc4340>. <https://www.rfc-editor.org/info/rfc4340>.
[RFC4632] Fuller, V. and T. Li, "Classless Inter-domain Routing
(CIDR): The Internet Address Assignment and Aggregation
Plan", BCP 122, RFC 4632, DOI 10.17487/RFC4632, August
2006, <https://www.rfc-editor.org/info/rfc4632>.
[RFC4732] Handley, M., Ed., Rescorla, E., Ed., and IAB, "Internet [RFC4732] Handley, M., Ed., Rescorla, E., Ed., and IAB, "Internet
Denial-of-Service Considerations", RFC 4732, Denial-of-Service Considerations", RFC 4732,
DOI 10.17487/RFC4732, December 2006, DOI 10.17487/RFC4732, December 2006,
<https://www.rfc-editor.org/info/rfc4732>. <https://www.rfc-editor.org/info/rfc4732>.
[RFC4787] Audet, F., Ed. and C. Jennings, "Network Address [RFC4787] Audet, F., Ed. and C. Jennings, "Network Address
Translation (NAT) Behavioral Requirements for Unicast Translation (NAT) Behavioral Requirements for Unicast
UDP", BCP 127, RFC 4787, DOI 10.17487/RFC4787, January UDP", BCP 127, RFC 4787, DOI 10.17487/RFC4787, January
2007, <https://www.rfc-editor.org/info/rfc4787>. 2007, <https://www.rfc-editor.org/info/rfc4787>.
skipping to change at page 96, line 10 skipping to change at page 96, line 44
[RFC6887] Wing, D., Ed., Cheshire, S., Boucadair, M., Penno, R., and [RFC6887] Wing, D., Ed., Cheshire, S., Boucadair, M., Penno, R., and
P. Selkirk, "Port Control Protocol (PCP)", RFC 6887, P. Selkirk, "Port Control Protocol (PCP)", RFC 6887,
DOI 10.17487/RFC6887, April 2013, DOI 10.17487/RFC6887, April 2013,
<https://www.rfc-editor.org/info/rfc6887>. <https://www.rfc-editor.org/info/rfc6887>.
[RFC6888] Perreault, S., Ed., Yamagata, I., Miyakawa, S., Nakagawa, [RFC6888] Perreault, S., Ed., Yamagata, I., Miyakawa, S., Nakagawa,
A., and H. Ashida, "Common Requirements for Carrier-Grade A., and H. Ashida, "Common Requirements for Carrier-Grade
NATs (CGNs)", BCP 127, RFC 6888, DOI 10.17487/RFC6888, NATs (CGNs)", BCP 127, RFC 6888, DOI 10.17487/RFC6888,
April 2013, <https://www.rfc-editor.org/info/rfc6888>. April 2013, <https://www.rfc-editor.org/info/rfc6888>.
[RFC7030] Pritikin, M., Ed., Yee, P., Ed., and D. Harkins, Ed.,
"Enrollment over Secure Transport", RFC 7030,
DOI 10.17487/RFC7030, October 2013,
<https://www.rfc-editor.org/info/rfc7030>.
[RFC7413] Cheng, Y., Chu, J., Radhakrishnan, S., and A. Jain, "TCP [RFC7413] Cheng, Y., Chu, J., Radhakrishnan, S., and A. Jain, "TCP
Fast Open", RFC 7413, DOI 10.17487/RFC7413, December 2014, Fast Open", RFC 7413, DOI 10.17487/RFC7413, December 2014,
<https://www.rfc-editor.org/info/rfc7413>. <https://www.rfc-editor.org/info/rfc7413>.
[RFC7452] Tschofenig, H., Arkko, J., Thaler, D., and D. McPherson, [RFC7452] Tschofenig, H., Arkko, J., Thaler, D., and D. McPherson,
"Architectural Considerations in Smart Object Networking", "Architectural Considerations in Smart Object Networking",
RFC 7452, DOI 10.17487/RFC7452, March 2015, RFC 7452, DOI 10.17487/RFC7452, March 2015,
<https://www.rfc-editor.org/info/rfc7452>. <https://www.rfc-editor.org/info/rfc7452>.
[RFC7589] Badra, M., Luchuk, A., and J. Schoenwaelder, "Using the [RFC7589] Badra, M., Luchuk, A., and J. Schoenwaelder, "Using the
skipping to change at page 96, line 35 skipping to change at page 97, line 26
[RFC7918] Langley, A., Modadugu, N., and B. Moeller, "Transport [RFC7918] Langley, A., Modadugu, N., and B. Moeller, "Transport
Layer Security (TLS) False Start", RFC 7918, Layer Security (TLS) False Start", RFC 7918,
DOI 10.17487/RFC7918, August 2016, DOI 10.17487/RFC7918, August 2016,
<https://www.rfc-editor.org/info/rfc7918>. <https://www.rfc-editor.org/info/rfc7918>.
[RFC7924] Santesson, S. and H. Tschofenig, "Transport Layer Security [RFC7924] Santesson, S. and H. Tschofenig, "Transport Layer Security
(TLS) Cached Information Extension", RFC 7924, (TLS) Cached Information Extension", RFC 7924,
DOI 10.17487/RFC7924, July 2016, DOI 10.17487/RFC7924, July 2016,
<https://www.rfc-editor.org/info/rfc7924>. <https://www.rfc-editor.org/info/rfc7924>.
[RFC7951] Lhotka, L., "JSON Encoding of Data Modeled with YANG",
RFC 7951, DOI 10.17487/RFC7951, August 2016,
<https://www.rfc-editor.org/info/rfc7951>.
[RFC8305] Schinazi, D. and T. Pauly, "Happy Eyeballs Version 2: [RFC8305] Schinazi, D. and T. Pauly, "Happy Eyeballs Version 2:
Better Connectivity Using Concurrency", RFC 8305, Better Connectivity Using Concurrency", RFC 8305,
DOI 10.17487/RFC8305, December 2017, DOI 10.17487/RFC8305, December 2017,
<https://www.rfc-editor.org/info/rfc8305>. <https://www.rfc-editor.org/info/rfc8305>.
[RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams", [RFC8340] Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018, BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
<https://www.rfc-editor.org/info/rfc8340>. <https://www.rfc-editor.org/info/rfc8340>.
[RFC8499] Hoffman, P., Sullivan, A., and K. Fujiwara, "DNS
Terminology", BCP 219, RFC 8499, DOI 10.17487/RFC8499,
January 2019, <https://www.rfc-editor.org/info/rfc8499>.
Authors' Addresses Authors' Addresses
Tirumaleswar Reddy (editor) Tirumaleswar Reddy (editor)
McAfee, Inc. McAfee, Inc.
Embassy Golf Link Business Park Embassy Golf Link Business Park
Bangalore, Karnataka 560071 Bangalore, Karnataka 560071
India India
Email: kondtir@gmail.com Email: kondtir@gmail.com
Mohamed Boucadair (editor) Mohamed Boucadair (editor)
Orange Orange
Rennes 35000 Rennes 35000
France France
Email: mohamed.boucadair@orange.com Email: mohamed.boucadair@orange.com
Prashanth Patil Prashanth Patil
Cisco Systems, Inc. Cisco Systems, Inc.
Email: praspati@cisco.com Email: praspati@cisco.com
Andrew Mortensen Andrew Mortensen
Arbor Networks, Inc. Arbor Networks, Inc.
2727 S. State St 2727 S. State St
Ann Arbor, MI 48104 Ann Arbor, MI 48104
United States United States
Email: amortensen@arbor.net Email: andrew@moretension.com
Nik Teague Nik Teague
Verisign, Inc. Verisign, Inc.
United States United States
Email: nteague@verisign.com Email: nteague@verisign.com
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