< draft-ietf-dots-signal-channel-21.txt   draft-ietf-dots-signal-channel-22.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: January 18, 2019 Orange Expires: February 8, 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.
July 17, 2018 August 7, 2018
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-21 draft-ietf-dots-signal-channel-22
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
purposes. purposes.
Editorial Note (To be removed by RFC Editor) Editorial Note (To be removed by RFC Editor)
Please update these statements with the RFC number to be assigned to Please update these statements within the document with the RFC
this document: number to be assigned to this document:
o "This version of this YANG module is part of RFC XXXX;" o "This version of this YANG module is part of RFC XXXX;"
o "RFC XXXX: Distributed Denial-of-Service Open Threat Signaling o "RFC XXXX: Distributed Denial-of-Service Open Threat Signaling
(DOTS) Signal Channel Specification"; (DOTS) Signal Channel Specification";
o "| [RFCXXXX] |" o "| [RFCXXXX] |"
o reference: RFC XXXX o reference: RFC XXXX
skipping to change at page 2, line 20 skipping to change at page 2, line 20
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 January 18, 2019. This Internet-Draft will expire on February 8, 2019.
Copyright Notice Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the Copyright (c) 2018 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
skipping to change at page 2, line 48 skipping to change at page 2, line 48
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Design Overview . . . . . . . . . . . . . . . . . . . . . . . 6 3. Design Overview . . . . . . . . . . . . . . . . . . . . . . . 6
4. DOTS Signal Channel: Messages & Behaviors . . . . . . . . . . 8 4. DOTS Signal Channel: Messages & Behaviors . . . . . . . . . . 8
4.1. DOTS Server(s) Discovery . . . . . . . . . . . . . . . . 8 4.1. DOTS Server(s) Discovery . . . . . . . . . . . . . . . . 8
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 . . . . . . . . . . . . . . . . . 10 4.4. DOTS Mitigation Methods . . . . . . . . . . . . . . . . . 10
4.4.1. Request Mitigation . . . . . . . . . . . . . . . . . 11 4.4.1. Request Mitigation . . . . . . . . . . . . . . . . . 11
4.4.2. Retrieve Information Related to a Mitigation . . . . 25 4.4.2. Retrieve Information Related to a Mitigation . . . . 27
4.4.3. Efficacy Update from DOTS Clients . . . . . . . . . . 33 4.4.2.1. DOTS Servers Sending Mitigation Status . . . . . 31
4.4.4. Withdraw a Mitigation . . . . . . . . . . . . . . . . 35 4.4.2.2. DOTS Clients Polling for Mitigation Status . . . 34
4.5. DOTS Signal Channel Session Configuration . . . . . . . . 36 4.4.3. Efficacy Update from DOTS Clients . . . . . . . . . . 35
4.5.1. Discover Configuration Parameters . . . . . . . . . . 38 4.4.4. Withdraw a Mitigation . . . . . . . . . . . . . . . . 37
4.5.2. Convey DOTS Signal Channel Session Configuration . . 42
4.5.3. Configuration Freshness and Notifications . . . . . . 47 4.5. DOTS Signal Channel Session Configuration . . . . . . . . 38
4.5.4. Delete DOTS Signal Channel Session Configuration . . 48 4.5.1. Discover Configuration Parameters . . . . . . . . . . 40
4.6. Redirected Signaling . . . . . . . . . . . . . . . . . . 49 4.5.2. Convey DOTS Signal Channel Session Configuration . . 44
4.7. Heartbeat Mechanism . . . . . . . . . . . . . . . . . . . 51 4.5.3. Configuration Freshness and Notifications . . . . . . 49
5. DOTS Signal Channel YANG Module . . . . . . . . . . . . . . . 52 4.5.4. Delete DOTS Signal Channel Session Configuration . . 50
5.1. Tree Structure . . . . . . . . . . . . . . . . . . . . . 52 4.6. Redirected Signaling . . . . . . . . . . . . . . . . . . 51
5.2. YANG Module . . . . . . . . . . . . . . . . . . . . . . . 54 4.7. Heartbeat Mechanism . . . . . . . . . . . . . . . . . . . 53
6. Mapping Parameters to CBOR . . . . . . . . . . . . . . . . . 68 5. DOTS Signal Channel YANG Module . . . . . . . . . . . . . . . 54
7. (D)TLS Protocol Profile and Performance Considerations . . . 70 5.1. Tree Structure . . . . . . . . . . . . . . . . . . . . . 54
7.1. (D)TLS Protocol Profile . . . . . . . . . . . . . . . . . 70 5.2. YANG Module . . . . . . . . . . . . . . . . . . . . . . . 56
7.2. (D)TLS 1.3 Considerations . . . . . . . . . . . . . . . . 71 6. Mapping Parameters to CBOR . . . . . . . . . . . . . . . . . 70
7.3. MTU and Fragmentation . . . . . . . . . . . . . . . . . . 72 7. (D)TLS Protocol Profile and Performance Considerations . . . 72
7.1. (D)TLS Protocol Profile . . . . . . . . . . . . . . . . . 72
7.2. (D)TLS 1.3 Considerations . . . . . . . . . . . . . . . . 74
7.3. MTU and Fragmentation . . . . . . . . . . . . . . . . . . 75
8. Mutual Authentication of DOTS Agents & Authorization of DOTS 8. Mutual Authentication of DOTS Agents & Authorization of DOTS
Clients . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 Clients . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 75 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 77
9.1. DOTS Signal Channel UDP and TCP Port Number . . . . . . . 75 9.1. DOTS Signal Channel UDP and TCP Port Number . . . . . . . 77
9.2. Well-Known 'dots' URI . . . . . . . . . . . . . . . . . . 75 9.2. Well-Known 'dots' URI . . . . . . . . . . . . . . . . . . 77
9.3. CoAP Response Code . . . . . . . . . . . . . . . . . . . 75 9.3. CoAP Response Code . . . . . . . . . . . . . . . . . . . 78
9.4. CoAP Option Number . . . . . . . . . . . . . . . . . . . 76 9.4. CoAP Option Number . . . . . . . . . . . . . . . . . . . 78
9.5. DOTS Signal Channel CBOR Mappings Registry . . . . . . . 76 9.5. DOTS Signal Channel CBOR Mappings Registry . . . . . . . 78
9.5.1. Registration Template . . . . . . . . . . . . . . . . 76 9.5.1. Registration Template . . . . . . . . . . . . . . . . 79
9.5.2. Initial Registry Content . . . . . . . . . . . . . . 77 9.5.2. Initial Registry Content . . . . . . . . . . . . . . 79
9.6. DOTS Signal Channel YANG Module . . . . . . . . . . . . . 78 9.6. DOTS Signal Channel YANG Module . . . . . . . . . . . . . 80
10. Security Considerations . . . . . . . . . . . . . . . . . . . 78 10. Security Considerations . . . . . . . . . . . . . . . . . . . 81
11. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 79 11. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 82
12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 79 12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 82
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 80 13. References . . . . . . . . . . . . . . . . . . . . . . . . . 82
13.1. Normative References . . . . . . . . . . . . . . . . . . 80 13.1. Normative References . . . . . . . . . . . . . . . . . . 82
13.2. Informative References . . . . . . . . . . . . . . . . . 82 13.2. Informative References . . . . . . . . . . . . . . . . . 84
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 86 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 88
1. Introduction 1. Introduction
A distributed denial-of-service (DDoS) attack is an attempt to make A distributed denial-of-service (DDoS) attack is an attempt to make
machines or network resources unavailable to their intended users. machines or network resources unavailable to their intended users.
In most cases, sufficient scale can be achieved by compromising In most cases, sufficient scale can be achieved by compromising
enough end-hosts and using those infected hosts to perpetrate and enough end-hosts and using those infected hosts to perpetrate and
amplify the attack. The victim in this attack can be an application amplify the attack. The victim in this attack can be an application
server, a host, a router, a firewall, or an entire network. server, a host, a router, a firewall, or an entire network.
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| |___| |____| |___ | | | |___| |____| |___ | |
|DOTS client| |DOTS gateway | | Internet | | DOTS server | |DOTS client| |DOTS gateway | | Internet | | DOTS server |
| | | | | | | | | | | | | | | |
+-----------+ +-------------+ \__________/ +-------------+ +-----------+ +-------------+ \__________/ +-------------+
Figure 2: Sample DOTS Deployment (2) Figure 2: Sample DOTS Deployment (2)
In typical deployments, the DOTS client belongs to a different In typical deployments, the DOTS client belongs to a different
administrative domain than the DOTS server. For example, the DOTS administrative domain than the DOTS server. For example, the DOTS
client is embedded in a firewall protecting services owned and client is embedded in a firewall protecting services owned and
operated by a domain, while the DOTS server is owned and operated by operated by a customer, while the DOTS server is owned and operated
a different domain providing DDoS mitigation services. The latter by a different administrative entity (service provider, typically)
might or might not provide connectivity services to the network providing DDoS mitigation services. The latter might or might not
hosting the DOTS client. provide connectivity services to the network hosting the DOTS client.
The DOTS server may (not) be co-located with the DOTS mitigator. In The DOTS server may (not) be co-located with the DOTS mitigator. In
typical deployments, the DOTS server belongs to the same typical deployments, the DOTS server belongs to the same
administrative domain as the mitigator. The DOTS client can administrative domain as the mitigator. The DOTS client can
communicate directly with a DOTS server or indirectly via a DOTS communicate directly with a DOTS server or indirectly via a DOTS
gateway. gateway.
The document adheres to the DOTS architecture The document adheres to the DOTS architecture
[I-D.ietf-dots-architecture]. The requirements for DOTS signal [I-D.ietf-dots-architecture]. The requirements for DOTS signal
channel protocol are documented in [I-D.ietf-dots-requirements]. channel protocol are documented in [I-D.ietf-dots-requirements].
skipping to change at page 6, line 17 skipping to change at page 6, line 17
The meaning of the symbols in YANG tree diagrams is defined in The meaning of the symbols in YANG tree diagrams is defined in
[RFC8340]. [RFC8340].
3. Design Overview 3. Design Overview
The DOTS signal channel is built on top of the Constrained The DOTS signal channel is built on top of the Constrained
Application Protocol (CoAP) [RFC7252], a lightweight protocol Application Protocol (CoAP) [RFC7252], a lightweight protocol
originally designed for constrained devices and networks. The many originally designed for constrained devices and networks. The many
features of CoAP (expectation of packet loss, support for features of CoAP (expectation of packet loss, support for
asynchronous non-confirmable messaging, congestion control, small asynchronous Non-confirmable messaging, congestion control, small
message overhead limiting the need for fragmentation, use of minimal message overhead limiting the need for fragmentation, use of minimal
resources, and support for (D)TLS) makes it a good candidate to build resources, and support for (D)TLS) makes it a good candidate to build
the DOTS signaling mechanism from. the DOTS signaling mechanism from.
The DOTS signal channel is layered on existing standards (Figure 3). The DOTS signal channel is layered on existing standards (Figure 3).
+---------------------+ +---------------------+
| DOTS Signal Channel | | DOTS Signal Channel |
+---------------------+ +---------------------+
| CoAP | | CoAP |
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+----------+----------+ +----------+----------+
| 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. In order to use a
distinct port number (as opposed to TBD), DOTS clients and servers distinct port number (as opposed to TBD), DOTS clients and servers
should support a configurable parameter to supply the port number to SHOULD support a configurable parameter to supply the port number to
use. The rationale for not using the default port number 5684 use. The rationale for not using the default port number 5684
((D)TLS CoAP) is to allow for differentiated behaviors in ((D)TLS CoAP) is to allow for differentiated behaviors in
environments where both a DOTS gateway and an IoT gateway (e.g., environments where both a DOTS gateway and an IoT gateway (e.g.,
Figure 3 of [RFC7452]) are present. 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 "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.
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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 [RFC6347] over UDP and TLS DOTS signaling can happen with DTLS [RFC6347] over UDP and TLS
[RFC5246] over TCP. Likewise, DOTS requests may be sent using IPv4 [RFC5246] over TCP. Likewise, DOTS requests may be sent using IPv4
or IPv6 transfer capabilities. A Happy Eyeballs procedure for DOTS or IPv6 transfer capabilities. A Happy Eyeballs procedure for DOTS
signal channel is specified in Section 4.3. signal channel is 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], CBOR is a binary Binary Object Representation (CBOR) [RFC7049], a binary encoding
encoding scheme designed for small code and message size. CBOR- scheme designed for small code and message size. CBOR-encoded
encoded payloads are used to carry signal channel-specific payload payloads are used to carry signal channel-specific payload messages
messages which convey request parameters and response information which convey request parameters and response information such as
such as errors. In order to allow the use of the same data models, errors. In order to allow the use of the same data models, [RFC7951]
[RFC7951] specifies the JSON encoding of YANG-modeled data. A specifies the JSON encoding of YANG-modeled data. A similar effort
similar effort for CBOR is defined in [I-D.ietf-core-yang-cbor]. for CBOR is defined in [I-D.ietf-core-yang-cbor].
From that standpoint, this document specifies a YANG module for From that standpoint, this document specifies a YANG module for
representing mitigation scopes and DOTS signal channel session representing DOTS mitigation scopes, DOTS signal channel session
configuration data (Section 5). Representing these data as CBOR data configuration data, and DOTS redirected signalling (Section 5).
is assumed to follow the rules in [I-D.ietf-core-yang-cbor] or those Representing these data as CBOR data is assumed to follow the rules
in [RFC7951] combined with JSON/CBOR conversion rules in [RFC7049]. in [I-D.ietf-core-yang-cbor] or those in [RFC7951] combined with
All parameters in the payload of the DOTS signal channel are mapped JSON/CBOR conversion rules in [RFC7049]. All parameters in the
to CBOR types as specified in Section 6. payload of the DOTS signal channel are mapped to CBOR types as
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 and 3.xx Response Codes payload included in CoAP responses with 2.xx and 3.xx Response Codes
MUST be of content type "application/cbor" (Section 5.5.1 of MUST be of content type "application/cbor" (Section 5.5.1 of
[RFC7252]). CoAP responses with 4.xx and 5.xx error Response Codes [RFC7252]). CoAP responses with 4.xx and 5.xx error Response Codes
MUST include a diagnostic payload (Section 5.5.2 of [RFC7252]). The MUST include a diagnostic payload (Section 5.5.2 of [RFC7252]). The
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distinct DOTS clients as conflicting, nor recommend a DOTS server distinct DOTS clients as conflicting, nor recommend a DOTS server
behavior for processing conflicting mitigation requests. Those behavior for processing conflicting mitigation requests. Those
considerations are implementation- and deployment-specific. considerations are implementation- and deployment-specific.
Nevertheless, the document specifies the mechanisms to notify DOTS Nevertheless, the document specifies the mechanisms to notify DOTS
clients when conflicts occur, including the conflict cause clients when conflicts occur, including the conflict cause
(Section 4.4). (Section 4.4).
In deployments where one or more translators (e.g., Traditional NAT In deployments where one or more translators (e.g., Traditional NAT
[RFC3022], CGN [RFC6888], NAT64 [RFC6146], NPTv6 [RFC6296]) are [RFC3022], CGN [RFC6888], NAT64 [RFC6146], NPTv6 [RFC6296]) are
enabled between the client's network and the DOTS server, DOTS signal enabled between the client's network and the DOTS server, DOTS signal
channel messages forwarded to a DOTS server must not include internal channel messages forwarded to a DOTS server MUST NOT include internal
IP addresses/prefixes and/or port numbers; external addresses/ IP addresses/prefixes and/or port numbers; external addresses/
prefixes and/or port numbers as assigned by the translator must be prefixes and/or port numbers as assigned by the translator MUST be
used instead. This document does not make any recommendation about used instead. This document does not make any recommendation about
possible translator discovery mechanisms. The following are some possible translator discovery mechanisms. The following are some
(non-exhaustive) deployment examples that may be considered: (non-exhaustive) deployment examples that may be considered:
o Port Control Protocol (PCP) [RFC6887] or Session Traversal o Port Control Protocol (PCP) [RFC6887] or Session Traversal
Utilities for NAT (STUN) [RFC5389] may be used to retrieve the Utilities for NAT (STUN) [RFC5389] may be used to retrieve the
external addresses/prefixes and/or port numbers. Information external addresses/prefixes and/or port numbers. Information
retrieved by means of PCP or STUN will be used to feed the DOTS retrieved by means of PCP or STUN will be used to feed the DOTS
signal channel messages that will be sent to a DOTS server. signal channel messages that will be sent to a DOTS server.
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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 a variety of
means (e.g., local configuration, or dynamic means such as DHCP). means (e.g., local configuration, or dynamic means such as DHCP).
The description of such means is out of scope of this document. 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
of a DOTS client when it sends requests (e.g., contact all servers, to be followed by a DOTS client to send DOTS requests when multiple
select one server among the list) when multiple DOTS servers are DOTS servers are provisioned (e.g., contact all DOTS servers, select
provisioned. 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".
Each DOTS operation is indicated by a path-suffix that indicates the Each DOTS operation is indicated by a path-suffix that indicates the
intended operation. The operation path (Table 1) is appended to the intended operation. The operation path (Table 1) is appended to the
path-prefix to form the URI used with a CoAP request to perform the path-prefix to form the URI used with a CoAP request to perform the
desired DOTS operation. desired DOTS operation.
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mitigations maintained by a DOTS server (Section 4.4.2). mitigations maintained by a DOTS server (Section 4.4.2).
DELETE: DOTS clients use the DELETE method to withdraw a request for DELETE: DOTS clients use the DELETE method to withdraw a request for
mitigation from a DOTS server (Section 4.4.4). mitigation from a DOTS server (Section 4.4.4).
Mitigation request and response messages are marked as Non- Mitigation request and response messages are marked as Non-
confirmable messages (Section 2.2 of [RFC7252]). confirmable messages (Section 2.2 of [RFC7252]).
DOTS agents SHOULD follow the data transmission guidelines discussed DOTS agents SHOULD follow the data transmission guidelines discussed
in Section 3.1.3 of [RFC8085] and control transmission behavior by in Section 3.1.3 of [RFC8085] and control transmission behavior by
not sending more than one UDP datagram per RTT to the peer DOTS agent not sending more than one UDP datagram per round-trip time (RTT) to
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]).
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, illustrated in JSON diagnostic notation). DOTS server(s) (Figure 5, illustrated in JSON diagnostic notation).
If this 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 can enable 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 and relaying
the feedback of the thus-selected mitigator to the requesting DOTS the feedback of the thus-selected mitigator to the requesting DOTS
client. client.
Header: PUT (Code=0.03) Header: PUT (Code=0.03)
Uri-Host: "host" Uri-Host: "host"
Uri-Path: ".well-known" Uri-Path: ".well-known"
Uri-Path: "dots" Uri-Path: "dots"
Uri-Path: "version" Uri-Path: "version"
skipping to change at page 12, line 39 skipping to change at page 12, line 39
], ],
"target-fqdn": [ "target-fqdn": [
"string" "string"
], ],
"target-uri": [ "target-uri": [
"string" "string"
], ],
"alias-name": [ "alias-name": [
"string" "string"
], ],
"lifetime": integer "lifetime": integer,
"trigger-mitigation": boolean
} }
] ]
} }
} }
Figure 5: PUT to Convey DOTS Mitigation Requests Figure 5: PUT to Convey DOTS Mitigation Requests
The Uri-Path option carries a major and minor version nomenclature to The Uri-Path option carries a major and minor version nomenclature to
manage versioning; DOTS signal channel in this specification uses manage versioning; DOTS signal channel in this specification uses
'v1' major version. 'v1' major version.
skipping to change at page 13, line 48 skipping to change at page 13, line 51
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. This is a mandatory Uri-Path.
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 relative to the 'mid'
parameter values of active mitigation requests conveyed from the parameter values of active mitigation requests conveyed from the
DOTS client to the DOTS server. In order to handle out-of-order DOTS client to the DOTS server.
delivery of mitigation requests, 'mid' values MUST increase
monotonically. In order to handle out-of-order delivery of mitigation requests,
'mid' values MUST increase monotonically.
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'
to 0 to handle 'mid' rollover. If the DOTS client maintains
mitigation requests with pre-configured scopes, it MUST re-create
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.
The parameters in the CBOR body of the PUT request are described The parameters in the CBOR body of the PUT request are described
below: below:
skipping to change at page 16, line 7 skipping to change at page 16, line 17
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
response and the remaining lifetime in status messages sent to the response and the remaining lifetime in status messages sent to the
DOTS client. DOTS client.
This is a mandatory attribute. This is a mandatory attribute.
trigger-mitigation: If the parameter value is set to 'false', DDoS
mitigation will not be triggered for the mitigation request unless
the DOTS signal channel session is lost.
If the DOTS client ceases to respond to heartbeat messages, the
DOTS server can detect that the DOTS session is lost.
The default value of the parameter is 'true' (that is, the
mitigation starts immediately). If 'trigger-mitigation' is not
present in a request, this is equivalent to receiving a request
with 'trigger-mitigation' set to 'true'.
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 supplied to the DOTS server. That information is meant to assist the
DOTS server to enforce some policies such as correlating DOTS clients DOTS server to enforce some policies such as correlating DOTS clients
that belong to the same DOTS domain, limiting the number of DOTS that belong to the same DOTS domain, limiting the number of DOTS
requests, and identifying the mitigation scope. These policies can requests, and identifying the mitigation scope. These policies can
be enforced per-client, per-client domain, or both. Also, the 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 6 shows an example of a request relayed by a server-domain
skipping to change at page 20, line 15 skipping to change at page 20, line 15
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. 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.
The relative order of two mitigation requests from a DOTS client is
determined by comparing their respective 'mid' values. If two
mitigation requests have overlapping mitigation scopes, the
mitigation request with the highest numeric 'mid' value will override
the other mitigation request. Two mitigation requests from a DOTS
client are overlapping if there is a common IP address, IP prefix,
FQDN, URI, or alias-name. To avoid maintaining a long list of
overlapping mitigation requests from a DOTS client and avoid error-
prone provisioning of mitigation requests from a DOTS client, the
overlapped lower numeric 'mid' MUST be automatically deleted and no
longer available at the DOTS server.
Figure 7 shows a PUT request example to signal that ports 80, 8080, Figure 7 shows a PUT request example to signal that ports 80, 8080,
and 443 used by 2001:db8:6401::1 and 2001:db8:6401::2 servers are and 443 used by 2001:db8:6401::1 and 2001:db8:6401::2 servers are
under attack (illustrated in JSON diagnostic notation). The presence under attack (illustrated in JSON diagnostic notation). The presence
of 'cdid' indicates that a server-domain DOTS gateway has modified of 'cdid' indicates that a server-domain DOTS gateway has modified
the initial PUT request sent by the DOTS client. Note that 'cdid' the initial PUT request sent by the DOTS client. Note that 'cdid'
MUST NOT appear in the PUT request message body. MUST NOT appear in the PUT request message body.
Header: PUT (Code=0.03) Header: PUT (Code=0.03)
Uri-Host: "www.example.com" Uri-Host: "www.example.com"
Uri-Path: ".well-known" Uri-Path: ".well-known"
skipping to change at page 22, line 32 skipping to change at page 22, line 32
A1 # map(1) A1 # map(1)
08 # unsigned(8) 08 # unsigned(8)
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)
A1 # map(1)
19 0E10 # unsigned(3600) 19 0E10 # unsigned(3600)
Figure 8: PUT for DOTS Mitigation Request (CBOR) Figure 8: 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
value, so the DOTS server can validate whether the aliases conveyed value, so the DOTS server can validate whether the aliases conveyed
in the mitigation request were indeed created by the same DOTS client in the mitigation request were indeed created by the same DOTS client
using the DOTS data channel session. If the aliases were not created using the DOTS data channel session. If the aliases were not created
by the DOTS client, the DOTS server MUST return 4.00 (Bad Request) in by the DOTS client, the DOTS server MUST return 4.00 (Bad Request) in
skipping to change at page 24, line 12 skipping to change at page 24, line 10
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.
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
'trigger-mitigation' type, from a DOTS client is determined by
comparing their respective 'mid' values. If two mitigation requests
with the same 'trigger-mitigation' type have overlapping mitigation
scopes, the mitigation request with the highest numeric 'mid' value
will override the other mitigation request. Two mitigation requests
from a DOTS client have overlapping scopes if there is a common IP
address, IP prefix, FQDN, URI, or alias-name. To avoid maintaining a
long list of overlapping mitigation requests (i.e., requests with the
same 'trigger-mitigation' type and overlapping scopes) from a DOTS
client and avoid error-prone provisioning of mitigation requests from
a DOTS client, the overlapped lower numeric 'mid' MUST be
automatically deleted and no longer available at the DOTS server.
For example, if the DOTS server receives a mitigation request which
overlaps with an existing mitigation with a higher numeric 'mid', the
DOTS server rejects the request by returning 4.09 (Conflict) to the
DOTS client. The response includes enough information for a DOTS
client to recognize the source of the conflict as described below:
conflict-information: Indicates that a mitigation request is
conflicting with another mitigation request. This optional
attribute has the following structure:
conflict-cause: Indicates the cause of the conflict. The
following values are defined:
1: Overlapping targets. 'conflict-scope' provides more details
about the conflicting target clauses.
conflict-scope: Indicates the conflict scope. It may include a
list of IP addresses, a list of prefixes, a list of port
numbers, a list of target protocols, a list of FQDNs, a list of
URIs, a list of alias-names, or a 'mid'.
If the DOTS server receives a mitigation request which overlaps with
an active mitigation request, but both having distinct 'trigger-
mitigation' types, the DOTS server MUST deactivate (absent explicit
policy/configuration otherwise) the mitigation request with 'trigger-
mitigation' set to false. Particularly, if the mitigation request
with 'trigger-mitigation' set to false is active, the DOTS server
withdraws the mitigation request (i.e., status code is set to '7' as
defined in Table 2) and transitions the status of the mitigation
request to '8'.
Upon DOTS signal channel session loss with a peer DOTS client, the
DOTS server MUST withdraw (absent explicit policy/configuration
otherwise) any active mitigation requests overlapping with mitigation
requests having 'trigger-mitigation' set to false from that DOTS
client. 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
immediate and pre-configured mitigation requests to avoid potential
conflicts. For example, a DOTS client may tweak pre-configured
scopes so that the scope of any overlapping immediate mitigation
request will be a subset of the pre-configured scopes. Also, if an
immediate mitigation request overlaps with any of the pre-configured
scopes, the DOTS client sets the scope of the overlapping immediate
mitigation request to be a subset of the pre-configured scopes.
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
of the conflict as described below: of the conflict as described below:
skipping to change at page 25, line 35 skipping to change at page 26, line 49
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
conflicting mitigation request. The lifetime of the conflicting mitigation request. The lifetime of the
deactivated mitigation request will be updated to (retry-timer deactivated mitigation request will be updated to (retry-timer
+ 45 seconds), so the DOTS client can refresh the deactivated + 45 seconds), so the DOTS client can refresh the deactivated
mitigation request after retry-timer seconds before expiry of mitigation request after retry-timer seconds before expiry of
lifetime and check if the conflict is resolved. lifetime and check if the conflict is resolved.
As an active attack evolves, DOTS clients can adjust the scope of As an active attack evolves, DOTS clients can adjust the scope of
requested mitigation as necessary, by refining the scope of resources requested mitigation as necessary, by refining the scope of resources
requiring mitigation. This can be achieved, for example, by (1) requiring mitigation. This can be achieved by sending a PUT request
sending a PUT request with a new 'mid' value that will override the with a new 'mid' value that will override the existing one with
existing one with overlapping mitigation scopes or (2) by re- using overlapping mitigation scopes.
the same 'mid' with updated mitigation scopes.
For a mitigation request to continue beyond the initial negotiated For a mitigation request to continue beyond the initial negotiated
lifetime, the DOTS client has to refresh the current mitigation lifetime, the DOTS client has to refresh the current mitigation
request by sending a new PUT request. This PUT request MUST use the request by sending a new PUT request. This PUT request MUST use the
same 'mid' value, and MUST repeat all the other parameters as sent in same 'mid' value, and MUST repeat all the other parameters as sent in
the original mitigation request apart from a possible change to the the original mitigation request apart from a possible change to the
lifetime parameter value. lifetime parameter value.
4.4.2. Retrieve Information Related to a Mitigation 4.4.2. Retrieve Information Related to a Mitigation
skipping to change at page 26, line 12 skipping to change at page 27, line 26
'cuid' is a mandatory Uri-Path parameter for GET requests. 'cuid' is a mandatory Uri-Path parameter for GET requests.
Uri-Path parameters with empty values MUST NOT be present in a Uri-Path parameters with empty values MUST NOT be present in a
request. request.
The same considerations for manipulating 'cdid' parameter by server- The same considerations for manipulating 'cdid' parameter by server-
domain DOTS gateways specified in Section 4.4.1 MUST be followed for domain DOTS gateways specified in Section 4.4.1 MUST be followed for
GET requests. GET requests.
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
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
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
mitigation record for that DOTS client. As a reminder, a DOTS client
is identified by its identity (e.g., client certificate, 'cuid') and
optionally the 'cdid'.
The 'c' (content) parameter and its permitted values defined in The 'c' (content) parameter and its permitted values defined in
[I-D.ietf-core-comi] can be used to retrieve non-configuration data [I-D.ietf-core-comi] can be used to retrieve non-configuration data
(attack mitigation status), configuration data, or both. The DOTS (attack mitigation status), configuration data, or both. The DOTS
server may support this optional filtering capability. It can safely server MAY support this optional filtering capability. It can safely
ignore it if not supported. ignore it if not supported.
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 10 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 11 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
skipping to change at page 27, line 17 skipping to change at page 28, line 28
Uri-Path: ".well-known" Uri-Path: ".well-known"
Uri-Path: "dots" Uri-Path: "dots"
Uri-Path: "v1" Uri-Path: "v1"
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 11: GET to Retrieve a Specific DOTS Mitigation Request
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
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
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
mitigation record for that DOTS client. As a reminder, a DOTS client
is identified by its identity (e.g., client certificate, 'cuid') and
optionally the 'cdid'.
Figure 12 shows a response example of all active mitigation requests Figure 12 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,
skipping to change at page 29, line 8 skipping to change at page 30, line 8
Figure 12: Response Body to a Get Request Figure 12: 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. This is a mandatory attribute when an attack mitigation is
triggered. Particularly, 'mitigation-start' is not returned for a
mitigation 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.
skipping to change at page 30, line 18 skipping to change at page 31, line 18
+-----------+-------------------------------------------------------+ +-----------+-------------------------------------------------------+
| 1 | Attack mitigation is in progress (e.g., changing the | | 1 | Attack mitigation is in progress (e.g., changing the |
| | network path to redirect the inbound traffic to a | | | network path to redirect the inbound traffic to a |
| | DOTS mitigator). | | | DOTS mitigator). |
+-----------+-------------------------------------------------------+ +-----------+-------------------------------------------------------+
| 2 | Attack is successfully mitigated (e.g., traffic is | | 2 | Attack is successfully mitigated (e.g., traffic is |
| | redirected to a DDoS mitigator and attack traffic is | | | redirected to a DDoS mitigator and attack traffic is |
| | dropped). | | | dropped). |
+-----------+-------------------------------------------------------+ +-----------+-------------------------------------------------------+
| 3 | Attack has stopped and the DOTS client can withdraw | | 3 | Attack has stopped and the DOTS client can withdraw |
| | the mitigation request. | | | the mitigation request. This status code will be |
| | transmitted for immediate mitigation requests till |
| | the mitigation is withdrawn or the lifetime expires. |
| | For mitigation requests with pre-configured scopes |
| | (i.e., 'trigger-mitigation' set to 'false'), this |
| | status code will be transmitted 4 times and then |
| | 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. | | 7 | Attack mitigation is withdrawn. If a mitigation |
| | request with 'trigger-mitigation' set to false is |
| | withdrawn because it overlaps with an immediate |
| | mitigation request, this status code will be |
| | transmitted 4 times and then transition to "8" for |
| | the mitigation request with pre-configured scopes. |
+-----------+-------------------------------------------------------+
| 8 | Attack mitigation will be triggered for the |
| | mitigation request only when the DOTS signal channel |
| | session is lost. |
+-----------+-------------------------------------------------------+ +-----------+-------------------------------------------------------+
Table 2: Values of 'status' Parameter Table 2: Values of 'status' Parameter
4.4.2.1. DOTS Servers Sending Mitigation Status
The Observe Option defined in [RFC7641] extends the CoAP core The Observe Option defined in [RFC7641] extends the CoAP core
protocol with a mechanism for a CoAP client to "observe" a resource protocol with a mechanism for a CoAP client to "observe" a resource
on a CoAP server: The client retrieves a representation of the on a CoAP server: The client retrieves a representation of the
resource and requests this representation be updated by the server as resource and requests this representation be updated by the server as
long as the client is interested in the resource. A DOTS client long as the client is interested in the resource. DOTS
conveys the Observe Option set to '0' in the GET request to receive implementations MUST use the Observe Option for both 'mitigate' and
unsolicited notifications of attack mitigation status from the DOTS 'config' (Section 4.2).
server.
Unidirectional notifications within the bidirectional signal channel A DOTS client conveys the Observe Option set to '0' in the GET
allows unsolicited message delivery, enabling asynchronous request to receive unsolicited notifications of attack mitigation
notifications between the agents. Due to the higher likelihood of status from the DOTS server.
packet loss during a DDoS attack, the DOTS server periodically sends
attack mitigation status to the DOTS client and also notifies the Unidirectional mitigation notifications within the bidirectional
DOTS client whenever the status of the attack mitigation changes. If signal channel allows unsolicited message delivery, enabling
the DOTS server cannot maintain an RTT estimate, it SHOULD NOT send asynchronous notifications between the agents. [RFC7641] indicates
more than one unsolicited notification every 3 seconds, and SHOULD that (1) a notification can be sent in a Confirmable (CON) or a Non-
use an even less aggressive rate whenever possible (case 2 in confirmable (NON) message, and (2) the message type used is typically
Section 3.1.3 of [RFC8085]). application dependent and may be determined by the server for each
notification individually. For DOTS server application, the message
type MUST always be set to Non-confirmable even if the underlying
COAP library elects a notification to be sent in a Confirmable
message.
Due to the higher likelihood of packet loss during a DDoS attack, the
DOTS server periodically sends attack mitigation status to the DOTS
client and also notifies the DOTS client whenever the status of the
attack mitigation changes. If the DOTS server cannot maintain an RTT
estimate, it SHOULD NOT send more than one unsolicited notification
every 3 seconds, and SHOULD use an even less aggressive rate whenever
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
corresponding policy (e.g., accept all requests, reject all requests, corresponding policy (e.g., accept all requests, reject all requests,
accept only one request but reject all the others, ...). It is accept only one request but reject all the others, ...). It is
assumed that this policy is supplied by the DOTS server administrator assumed that this policy is supplied by the DOTS server administrator
or it is a default behavior of the DOTS server implementation. Then, or it is a default behavior of the DOTS server implementation. Then,
the DOTS server sends notification message(s) to the DOTS client(s) the DOTS server sends notification message(s) to the DOTS client(s)
at the origin of the conflict (refer to the conflict parameters at the origin of the conflict (refer to the conflict parameters
defined in Section 4.4.1). A conflict notification message includes defined in Section 4.4.1). A conflict notification message includes
information about the conflict cause, scope, and the status of the information about the conflict cause, scope, and the status of the
skipping to change at page 31, line 43 skipping to change at page 33, line 22
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).
Figure 13 shows an example of a DOTS client requesting a DOTS server Figure 13 shows an example of a DOTS client requesting a DOTS server
to send notifications related to a given mitigation request. to send notifications related to a mitigation request. Note that for
mitigations with pre-configured scopes (i.e., 'trigger-mitigation'
set to 'false'), the state will need to transition from 3 (attack-
stopped) to 8 (attack-mitigation-signal-loss).
+-----------+ +-----------+ +-----------+ +-----------+
|DOTS client| |DOTS server| |DOTS client| |DOTS server|
+-----------+ +-----------+ +-----------+ +-----------+
| | | |
| GET /<mid> | | GET /<mid> |
| Token: 0x4a | Registration | Token: 0x4a | Registration
| Observe: 0 | | Observe: 0 |
+---------------------------------->| +----------------------------------------->|
| | | |
| 2.05 Content | | 2.05 Content |
| Token: 0x4a | Notification of | Token: 0x4a | Notification of
| Observe: 12 | the current state | Observe: 12 | the current state
| status: "mitigation in progress" | | status: "attack-mitigation-in-progress" |
| | | |
|<----------------------------------+ |<-----------------------------------------+
| 2.05 Content | | 2.05 Content |
| Token: 0x4a | Notification upon | Token: 0x4a | Notification upon
| Observe: 44 | a state change | Observe: 44 | a state change
| status: "mitigation complete" | | status: "attack-successfully-mitigated" |
| | | |
|<----------------------------------+ |<-----------------------------------------+
| 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 13: Notifications of Attack Mitigation Status
4.4.2.1. 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.
skipping to change at page 32, line 52 skipping to change at page 35, line 4
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 acknowledging by
itself, using its own means, that the attack has been mitigated. itself, using its own means, that the attack has been mitigated.
This ensures that the DOTS client does not recall a mitigation This ensures that the DOTS client does not recall a mitigation
request prematurely because it is possible that the DOTS client does request prematurely because it is possible that the DOTS client does
not sense the DDoS attack on its resources, but the DOTS server could not sense the DDoS attack on its resources, but the DOTS server could
be actively mitigating the attack because the attack is not be actively mitigating the attack because the attack is not
completely averted. 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. to convey the mitigation efficacy update to the DOTS server. This
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
parameters used in the PUT request to carry the DOTS mitigation parameters used in the PUT request to carry the DOTS mitigation
request (Section 4.4.1) unchanged apart from the 'lifetime' parameter request (Section 4.4.1) unchanged apart from the 'lifetime' parameter
value. If this is not the case, the DOTS server MUST reject the value. If this is not the case, the DOTS server MUST reject the
request with a 4.00 (Bad Request). request with a 4.00 (Bad Request).
The If-Match Option (Section 5.10.8.1 of [RFC7252]) with an empty The If-Match Option (Section 5.10.8.1 of [RFC7252]) with an empty
value is used to make the PUT request conditional on the current value is used to make the PUT request conditional on the current
existence of the mitigation request. If UDP is used as transport, existence of the mitigation request. If UDP is used as transport,
skipping to change at page 36, line 36 skipping to change at page 38, line 36
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 active-but-terminating period up to a maximum of 300
seconds (5 minutes). 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
server relies upon normal triggers to stop that mitigation
(typically, receipt of a valid DELETE request, expiry of the
mitigation lifetime, or observation of traffic to the attack target).
In particular, the DOTS server MUST NOT consider the signal channel
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
send heartbeats (CoAP Ping/Pong) to each other after mutual send heartbeats (CoAP Ping/Pong) to each other after mutual
authentication is successfully completed in order to keep the authentication is successfully completed in order to keep the
DOTS signal channel open. Heartbeat messages are exchanged DOTS signal channel open. Heartbeat messages are exchanged
skipping to change at page 37, line 24 skipping to change at page 39, line 31
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 Requests and responses are deemed reliable by marking them as
Confirmable (CON) messages. DOTS signal channel session Confirmable messages. DOTS signal channel session configuration
configuration requests and responses are marked as Confirmable requests and responses are marked as Confirmable messages. As
messages. As explained in Section 2.1 of [RFC7252], a Confirmable explained in Section 2.1 of [RFC7252], a Confirmable message is
message is retransmitted using a default timeout and exponential retransmitted using a default timeout and exponential back-off
back-off between retransmissions, until the DOTS server sends an 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 message is explained in Section 2.2 of [RFC7252]. When the response
skipping to change at page 39, line 36 skipping to change at page 41, line 46
"ack-timeout": { "ack-timeout": {
"max-value-decimal": number, "max-value-decimal": number,
"min-value-decimal": number, "min-value-decimal": number,
"current-value-decimal": number "current-value-decimal": number
}, },
"ack-random-factor": { "ack-random-factor": {
"max-value-decimal": number, "max-value-decimal": number,
"min-value-decimal": number, "min-value-decimal": number,
"current-value-decimal": number "current-value-decimal": number
} }
}, }
"trigger-mitigation": boolean
} }
} }
Figure 17: GET Configuration Response Body Figure 17: GET Configuration Response Body
The parameters in Figure 17 are described below: The parameters in Figure 17 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:
skipping to change at page 40, line 34 skipping to change at page 42, line 44
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'.
trigger-mitigation: If the parameter value is set to 'false', then
DDoS mitigation is triggered only when the DOTS signal channel
session is lost. Automated mitigation on loss of signal is
discussed in Section 3.3.3 of [I-D.ietf-dots-architecture].
If the DOTS client ceases to respond to heartbeat messages, the
DOTS server can detect that the DOTS session is lost.
The default value of the parameter is 'true'.
This is an optional attribute.
Figure 18 shows an example of acceptable and current configuration Figure 18 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. attack and peace times.
Content-Format: "application/cbor" Content-Format: "application/cbor"
{ {
"ietf-dots-signal-channel:signal-config": { "ietf-dots-signal-channel:signal-config": {
"mitigating-config": { "mitigating-config": {
"heartbeat-interval": { "heartbeat-interval": {
skipping to change at page 42, line 4 skipping to change at page 43, line 50
}, },
"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": 30.0,
"min-value-decimal": 1.0, "min-value-decimal": 1.0,
"current-value-decimal": 2.0 "current-value-decimal": 2.0
}, },
"ack-random-factor": { "ack-random-factor": {
"max-value-decimal": 4.0, "max-value-decimal": 4.0,
"min-value-decimal": 1.1, "min-value-decimal": 1.1,
"current-value-decimal": 1.5 "current-value-decimal": 1.5
} }
}, }
"trigger-mitigation": true
} }
} }
Figure 18: Example of a Configuration Response Body Figure 18: 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 is used to convey the configuration parameters for the
signal channel (e.g., heartbeat interval, maximum retransmissions). signal channel (e.g., heartbeat interval, maximum retransmissions).
Message transmission parameters for CoAP are defined in Section 4.8 Message transmission parameters for CoAP are defined in Section 4.8
of [RFC7252]. The RECOMMENDED values of transmission parameter of [RFC7252]. The RECOMMENDED values of transmission parameter
values are ack-timeout (2 seconds), max-retransmit (3), ack-random- values are ack-timeout (2 seconds), max-retransmit (3), ack-random-
factor (1.5). In addition to those parameters, the RECOMMENDED factor (1.5). In addition to those parameters, the RECOMMENDED
specific DOTS transmission parameter values are 'heartbeat-interval' specific DOTS transmission parameter values are 'heartbeat-interval'
(30 seconds) and 'missing-hb-allowed' (5). (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-010 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
standpoint, this specification recommends a minimum heartbeat- standpoint, this specification recommends a minimum heartbeat-
interval of 15 seconds and a maximum heartbeat-interval of 240 interval of 15 seconds and a maximum heartbeat-interval of 240
seconds. The recommended value of 30 seconds is selected to seconds. The recommended value of 30 seconds is selected to
skipping to change at page 43, line 6 skipping to change at page 44, line 51
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 transversal issues, or set session timeout to prevent translator traversal issues, or set to
to '0'. Means to discover the lifetime assigned by a translator '0'. Means to discover the lifetime assigned by a translator are
are out of scope. 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
DOTS signal channel session is disconnected. A DOTS client MUST NOT DOTS signal channel session is disconnected. A DOTS client MUST NOT
transmit a "CoAP Ping" while waiting for the previous "CoAP Ping" transmit a "CoAP Ping" while waiting for the previous "CoAP Ping"
response from the same DOTS server. response from the same DOTS server.
If the DOTS agent wishes to change the default values of message If the DOTS agent wishes to change the default values of message
transmission parameters, it should follow the guidance given in transmission parameters, it SHOULD follow the guidance given in
Section 4.8.1 of [RFC7252]. The DOTS agents MUST use the negotiated Section 4.8.1 of [RFC7252]. The DOTS agents MUST use the negotiated
values for message transmission parameters and default values for values for message transmission parameters and default values for
non-negotiated message transmission parameters. non-negotiated message transmission parameters.
The signal channel session configuration is applicable to a single The signal channel session configuration is applicable to a single
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-Host: "host" Uri-Host: "host"
skipping to change at page 44, line 29 skipping to change at page 46, line 26
}, },
"max-retransmit": { "max-retransmit": {
"current-value": integer "current-value": integer
}, },
"ack-timeout": { "ack-timeout": {
"current-value-decimal": number "current-value-decimal": number
}, },
"ack-random-factor": { "ack-random-factor": {
"current-value-decimal": number "current-value-decimal": number
} }
}, }
"trigger-mitigation": boolean
} }
} }
Figure 19: PUT to Convey the DOTS Signal Channel Session Figure 19: PUT to Convey the DOTS Signal Channel Session
Configuration Data Configuration Data
The additional Uri-Path parameter to those defined in Table 1 is as The additional Uri-Path parameter to those defined in Table 1 is as
follows: follows:
sid: Session Identifier is an identifier for the DOTS signal channel sid: Session Identifier is an identifier for the DOTS signal channel
session configuration data represented as an integer. This session configuration data represented as an integer. This
identifier MUST be generated by DOTS clients. 'sid' values MUST identifier MUST be generated by DOTS clients. 'sid' values MUST
increase monotonically. increase monotonically.
This is a mandatory attribute. 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 is defined in
Section 4.5.1. 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', 'ack-random-factor', and allowed', 'max-retransmit', 'ack-timeout', and 'ack-random-factor'
'trigger-mitigation' MUST be present in the PUT request. Note that MUST be present in the PUT request. Note that 'heartbeat-interval',
'heartbeat-interval', 'missing-hb-allowed', 'max-retransmit', 'ack- 'missing-hb-allowed', 'max-retransmit', 'ack-timeout', and 'ack-
timeout', and 'ack-random-factor', if present, do not need to be random-factor', if present, do not need to be provided for both
provided for both 'mitigating-config', and 'idle-config' in a PUT 'mitigating-config', and 'idle-config' in a PUT request.
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 20 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
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}, },
"max-retransmit": { "max-retransmit": {
"current-value": 3 "current-value": 3
}, },
"ack-timeout": { "ack-timeout": {
"current-value-decimal": 2.0 "current-value-decimal": 2.0
}, },
"ack-random-factor": { "ack-random-factor": {
"current-value-decimal": 1.5 "current-value-decimal": 1.5
} }
}, }
"trigger-mitigation": false
} }
} }
Figure 20: PUT to Convey the Configuration Parameters Figure 20: 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
DOTS server has accepted the configuration parameters, then a DOTS server has accepted the configuration parameters, then a
response code 2.01 (Created) is returned in the response. response code 2.01 (Created) MUST be returned in the response.
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.
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change occurs at the DOTS server side. For example, the new change occurs at the DOTS server side. For example, the new
configuration may instruct a DOTS client to cease heartbeats or configuration may instruct a DOTS client to cease heartbeats or
reduce heartbeat frequency. reduce heartbeat frequency.
It is NOT RECOMMENDED to return a Max-Age Option set to 0. It is NOT RECOMMENDED to return a Max-Age Option set to 0.
Returning a Max-Age Option set to 2**32-1 is equivalent to Returning a Max-Age Option set to 2**32-1 is equivalent to
associating an infinite lifetime with the configuration. associating an infinite lifetime with the configuration.
If a non-zero value of Max-Age Option is received by a DOTS client, If a non-zero value of Max-Age Option is received by a DOTS client,
it MUST issue a GET request to refresh the configuration parameters it MUST issue a GET request with 'sid' Uri-Path parameter to retrieve
for the signal channel before the expiry of the value enclosed in the the current and acceptable configuration before the expiry of the
Max-Age option. When a DDoS attack is active, refresh requests MUST value enclosed in the Max-Age option. This request is considered by
NOT be sent by DOTS clients and the DOTS server MUST NOT terminate the client and the server as a means to refresh the configuration
the (D)TLS session after the expiry of the value returned in Max-Age parameters for the signal channel. When a DDoS attack is active,
Option. refresh requests MUST NOT be sent by DOTS clients and the DOTS server
MUST NOT terminate the (D)TLS session after the expiry of the value
returned in Max-Age Option.
If Max-Age Option is not returned in a response, the DOTS client If Max-Age Option is not returned in a response, the DOTS client
initiates GET requests to refresh the configuration parameters each initiates GET requests to refresh the configuration parameters each
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
skipping to change at page 48, line 41 skipping to change at page 50, line 40
session configuration data (Figure 21). session configuration data (Figure 21).
Header: DELETE (Code=0.04) Header: DELETE (Code=0.04)
Uri-Host: "host" Uri-Host: "host"
Uri-Path: ".well-known" Uri-Path: ".well-known"
Uri-Path: "dots" Uri-Path: "dots"
Uri-Path: "v1" Uri-Path: "v1"
Uri-Path: "config" Uri-Path: "config"
Uri-Path: "sid=123" Uri-Path: "sid=123"
Figure 21: DELETE Configuration Figure 21: 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 bootsrapping 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'.
4.6. Redirected Signaling 4.6. Redirected Signaling
Redirected DOTS signaling is discussed in detail in Section 3.2.2 of Redirected DOTS signaling is discussed in detail in Section 3.2.2 of
[I-D.ietf-dots-architecture]. [I-D.ietf-dots-architecture].
If a DOTS server wants to redirect a DOTS client to an alternative If a DOTS server wants to redirect a DOTS client to an alternative
DOTS server for a signal session, then the response code 3.00 DOTS server for a signal session, then the response code 3.00
skipping to change at page 50, line 51 skipping to change at page 52, line 51
Figure 23: Example of Redirected Server Error Response Body Figure 23: Example of Redirected Server Error Response Body
When the DOTS client receives 3.00 response, it considers the current When the DOTS client receives 3.00 response, it considers the current
request as failed, but SHOULD try re-sending the request to the request as failed, but SHOULD try re-sending the request to the
alternate DOTS server. During a DDoS attack, the DNS server may be alternate DOTS server. During a DDoS attack, the DNS server may be
the target of another DDoS attack, alternate DOTS server's IP the target of another DDoS attack, alternate DOTS server's IP
addresses conveyed in the 3.00 response help the DOTS client skip DNS addresses conveyed in the 3.00 response help the DOTS client skip DNS
lookup of the alternate DOTS server. The DOTS client can then try to lookup of the alternate DOTS server. The DOTS client can then try to
establish a UDP or a TCP session with the alternate DOTS server. The establish a UDP or a TCP session with the alternate DOTS server. The
DOTS client SHOULD implement a DNS64 function to handle the scenario DOTS client MAY implement a method to construct IPv4-embedded IPv6
where an IPv6-only DOTS client communicates with an IPv4-only addresses [RFC6052]; this is required to handle the scenario where an
alternate DOTS server. 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
skipping to change at page 52, line 36 skipping to change at page 54, line 36
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 4.4
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 Module 5. DOTS Signal Channel YANG Module
This document defines a YANG [RFC7950] module for mitigation scope This document defines a YANG [RFC7950] module for DOTS mitigation
and DOTS signal channel session configuration data. scope, DOTS signal channel session configuration data, and DOTS
redirected signalling.
This YANG module defines the DOTS client interaction with the DOTS This YANG module defines the DOTS client interaction with the DOTS
server as seen by the DOTS client. A DOTS server is allowed to server as seen by the DOTS client. A DOTS server is allowed to
update the non-configurable 'ro' entities in the responses. This update the non-configurable 'ro' entities in the responses. This
YANG module is not intended to be used for DOTS server management YANG module is not intended to be used for DOTS server management
purposes. Such module is out of the scope of this document. purposes. Such module is out of the scope of this document.
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"
skipping to change at page 53, line 12 skipping to change at page 55, line 13
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 upper-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
| +--ro mitigation-start? uint64 | +--ro mitigation-start? uint64
| +--ro status? enumeration | +--ro status? enumeration
| +--ro conflict-information | +--ro conflict-information
| | +--ro conflict-status? enumeration | | +--ro conflict-status? enumeration
| | +--ro conflict-cause? enumeration | | +--ro conflict-cause? enumeration
| | +--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 upper-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-acl:acls/acl/name
| | | -> /ietf-acl:acls/acl/name | | | +--ro acl-type? -> /ietf-acl:acls/acl/type
| | +--ro acl-type? | | +--ro mid? -> ../../../mid
| | -> /ietf-acl:acls/acl/type
| +--ro bytes-dropped? yang:zero-based-counter64 | +--ro bytes-dropped? yang:zero-based-counter64
| +--ro bps-dropped? yang:zero-based-counter64 | +--ro bps-dropped? yang:zero-based-counter64
| +--ro pkts-dropped? yang:zero-based-counter64 | +--ro pkts-dropped? yang:zero-based-counter64
| +--ro pps-dropped? yang:zero-based-counter64 | +--ro pps-dropped? yang:zero-based-counter64
| +--rw attack-status? enumeration | +--rw attack-status? enumeration
+--:(signal-config) +--:(signal-config)
| +--rw sid uint32 | +--rw sid uint32
| +--rw mitigating-config | +--rw mitigating-config
| | +--rw heartbeat-interval | | +--rw heartbeat-interval
| | | +--ro max-value? uint16 | | | +--ro max-value? uint16
skipping to change at page 54, line 20 skipping to change at page 56, line 21
| | | +--rw current-value? uint16 | | | +--rw current-value? uint16
| | +--rw ack-timeout | | +--rw ack-timeout
| | | +--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
| | +--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
| +--rw idle-config | +--rw idle-config
| | +--rw heartbeat-interval | +--rw heartbeat-interval
| | | +--ro max-value? uint16 | | +--ro max-value? uint16
| | | +--ro min-value? uint16 | | +--ro min-value? uint16
| | | +--rw current-value? uint16 | | +--rw current-value? uint16
| | +--rw missing-hb-allowed | +--rw missing-hb-allowed
| | | +--ro max-value? uint16 | | +--ro max-value? uint16
| | | +--ro min-value? uint16 | | +--ro min-value? uint16
| | | +--rw current-value? uint16 | | +--rw current-value? uint16
| | +--rw max-retransmit | +--rw max-retransmit
| | | +--ro max-value? uint16 | | +--ro max-value? uint16
| | | +--ro min-value? uint16 | | +--ro min-value? uint16
| | | +--rw current-value? uint16 | | +--rw current-value? uint16
| | +--rw ack-timeout | +--rw ack-timeout
| | | +--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
| | +--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
| +--rw trigger-mitigation? boolean
+--:(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
+--ro alt-server-ttl? int32 +--ro alt-server-ttl? int32
5.2. YANG Module 5.2. YANG Module
<CODE BEGINS> file "ietf-dots-signal-channel@2018-05-29.yang" <CODE BEGINS> file "ietf-dots-signal-channel@2018-08-07.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;
} }
import ietf-yang-types { import ietf-yang-types {
skipping to change at page 56, line 6 skipping to change at page 58, line 6
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 2018-05-29 { revision 2018-08-07 {
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 58, line 33 skipping to change at page 60, line 33
default "3600"; default "3600";
description description
"Indicates the lifetime of the mitigation request. "Indicates the lifetime of the mitigation request.
A lifetime of '0' in a mitigation request is an A lifetime of '0' in a mitigation request is an
invalid value. invalid value.
A lifetime of negative one (-1) indicates indefinite A lifetime of negative one (-1) indicates indefinite
lifetime for the mitigation request."; lifetime for the mitigation request.";
} }
leaf trigger-mitigation {
type boolean;
default "true";
description
"If set to 'false', DDoS mitigation will not be
triggered unless the DOTS signal channel
session is lost.";
}
leaf mitigation-start { leaf mitigation-start {
type uint64; type uint64;
config false; config false;
description description
"Mitigation start time is represented in seconds "Mitigation start time is represented in seconds
relative to 1970-01-01T00:00:00Z in UTC time."; relative to 1970-01-01T00:00:00Z in UTC time.";
} }
leaf status { leaf status {
type enumeration { type enumeration {
enum "attack-mitigation-in-progress" { enum "attack-mitigation-in-progress" {
skipping to change at page 59, line 36 skipping to change at page 61, line 44
enum "attack-mitigation-terminated" { enum "attack-mitigation-terminated" {
value 6; value 6;
description description
"Attack mitigation is now terminated."; "Attack mitigation is now terminated.";
} }
enum "attack-mitigation-withdrawn" { enum "attack-mitigation-withdrawn" {
value 7; value 7;
description description
"Attack mitigation is withdrawn."; "Attack mitigation is withdrawn.";
} }
enum "attack-mitigation-signal-loss" {
value 8;
description
"Attack mitigation will be triggered
for the mitigation request only when
the DOTS signal channel session is lost.";
}
} }
config false; config false;
description description
"Indicates the status of a mitigation request. "Indicates the status of a mitigation request.
It must be included in responses only."; It must be included in responses only.";
} }
container conflict-information { container conflict-information {
config false; config false;
description description
"Indicates that a conflict is detected. "Indicates that a conflict is detected.
skipping to change at page 62, line 4 skipping to change at page 64, line 19
a DOTS client."; a DOTS client.";
} }
leaf acl-type { leaf acl-type {
type leafref { type leafref {
path "/ietf-acl:acls/ietf-acl:acl/" + path "/ietf-acl:acls/ietf-acl:acl/" +
"ietf-acl:type"; "ietf-acl:type";
} }
description description
"Reference to the conflicting ACL type bound to "Reference to the conflicting ACL type bound to
a DOTS client."; a DOTS client.";
} }
} }
leaf mid {
when "../../conflict-cause = 'overlapping-targets'";
type leafref {
path "../../../mid";
}
description
"Reference to the conflicting 'mid' bound to
the same DOTS client.";
}
} }
} }
leaf bytes-dropped { leaf bytes-dropped {
type yang:zero-based-counter64; type yang:zero-based-counter64;
units "bytes"; units "bytes";
config false; config false;
description description
"The total dropped byte count for the mitigation "The total dropped byte count for the mitigation
request since the attack mitigation is triggered. request since the attack mitigation is triggered.
The count wraps around when it reaches the maximum value The count wraps around when it reaches the maximum value
skipping to change at page 66, line 37 skipping to change at page 69, line 13
"Configuration parameters to use when a mitigation "Configuration parameters to use when a mitigation
is active."; is active.";
uses config-parameters; uses config-parameters;
} }
container idle-config { container idle-config {
description description
"Configuration parameters to use when no mitigation "Configuration parameters to use when no mitigation
is active."; is active.";
uses config-parameters; uses config-parameters;
} }
leaf trigger-mitigation {
type boolean;
default "true";
description
"If false, then mitigation is triggered
only when the DOTS server channel session is lost.";
}
} }
grouping redirected-signal { grouping redirected-signal {
description description
"Grouping for the redirected signaling."; "Grouping for the redirected signaling.";
leaf alt-server { leaf alt-server {
type string; type string;
config false; config false;
mandatory true; mandatory true;
description description
skipping to change at page 72, line 41 skipping to change at page 75, line 22
{EncryptedExtensions} {EncryptedExtensions}
{ServerConfiguration} {ServerConfiguration}
{Certificate} {Certificate}
{CertificateVerify} {CertificateVerify}
{Finished} {Finished}
<-------- [DOTS signal message] <-------- [DOTS signal message]
{Finished} --------> {Finished} -------->
[DOTS signal message] <-------> [DOTS signal message] [DOTS signal message] <-------> [DOTS signal message]
Figure 24: TLS 1.3 handshake with 0-RTT Figure 24: TLS 1.3 Handshake with 0-RTT
7.3. MTU and Fragmentation 7.3. 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. If UDP is used to convey the DOTS signal messages then
the DOTS client must consider the amount of record expansion expected the DOTS client must consider the amount of record expansion expected
by the DTLS processing when calculating the size of CoAP message that by the DTLS processing when calculating the size of CoAP message that
skipping to change at page 79, line 33 skipping to change at page 82, line 7
(e.g., source IP address, client's hostname) unless explicitly (e.g., source IP address, client's hostname) unless explicitly
configured to do so. configured to do so.
DOTS servers MUST verify that requesting DOTS clients are entitled to DOTS servers MUST verify that requesting DOTS clients are entitled to
trigger actions on a given IP prefix. That is, only actions on IP trigger actions on a given IP prefix. That is, only actions on IP
resources that belong to the DOTS client' domain MUST be authorized resources that belong to the DOTS client' domain MUST be authorized
by a DOTS server. The exact mechanism for the DOTS servers to by a DOTS server. The exact mechanism for the DOTS servers to
validate that the target prefixes are within the scope of the DOTS validate that the target prefixes are within the scope of the DOTS
client's domain is deployment-specific. client's domain is deployment-specific.
The presence of DOTS gateways may lead to infinite forwarding loops,
which is undesirable. To prevent and detect such loops, this
document specifies the 'hop-limit' option (Section 4.4.1).
CoAP-specific security considerations are discussed in Section 11 of
[RFC7252], while CBOR-related security considerations are discussed
in Section 8 of [RFC7049].
11. Contributors 11. Contributors
The following individuals have contributed to this document: The following individuals have contributed to this document:
o Jon Shallow, NCC Group, Email: jon.shallow@nccgroup.trust o Jon Shallow, NCC Group, Email: jon.shallow@nccgroup.trust
o Mike Geller, Cisco Systems, Inc. 3250 Florida 33309 USA, Email: o Mike Geller, Cisco Systems, Inc. 3250 Florida 33309 USA, Email:
mgeller@cisco.com mgeller@cisco.com
o Robert Moskowitz, HTT Consulting Oak Park, MI 42837 United States, o Robert Moskowitz, HTT Consulting Oak Park, MI 42837 United States,
skipping to change at page 80, line 5 skipping to change at page 82, line 36
o Dan Wing, Email: dwing-ietf@fuggles.com o Dan Wing, Email: dwing-ietf@fuggles.com
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, and Nesredien Suleiman for the discussion and Xia, Gilbert Clark, and Nesredien Suleiman for the discussion and
comments. comments.
Special thanks to Jon Shallow for the careful reviews and inputs that
enhanced this specification.
13. References 13. References
13.1. Normative References 13.1. Normative References
[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,
skipping to change at page 81, line 5 skipping to change at page 83, line 38
DOI 10.17487/RFC6066, January 2011, DOI 10.17487/RFC6066, January 2011,
<https://www.rfc-editor.org/info/rfc6066>. <https://www.rfc-editor.org/info/rfc6066>.
[RFC6125] Saint-Andre, P. and J. Hodges, "Representation and [RFC6125] Saint-Andre, P. and J. Hodges, "Representation and
Verification of Domain-Based Application Service Identity Verification of Domain-Based Application Service Identity
within Internet Public Key Infrastructure Using X.509 within Internet Public Key Infrastructure Using X.509
(PKIX) Certificates in the Context of Transport Layer (PKIX) Certificates in the Context of Transport Layer
Security (TLS)", RFC 6125, DOI 10.17487/RFC6125, March Security (TLS)", RFC 6125, DOI 10.17487/RFC6125, March
2011, <https://www.rfc-editor.org/info/rfc6125>. 2011, <https://www.rfc-editor.org/info/rfc6125>.
[RFC6234] Eastlake 3rd, D. and T. Hansen, "US Secure Hash Algorithms
(SHA and SHA-based HMAC and HKDF)", RFC 6234,
DOI 10.17487/RFC6234, May 2011,
<https://www.rfc-editor.org/info/rfc6234>.
[RFC6347] Rescorla, E. and N. Modadugu, "Datagram Transport Layer [RFC6347] Rescorla, E. and N. Modadugu, "Datagram Transport Layer
Security Version 1.2", RFC 6347, DOI 10.17487/RFC6347, Security Version 1.2", RFC 6347, DOI 10.17487/RFC6347,
January 2012, <https://www.rfc-editor.org/info/rfc6347>. January 2012, <https://www.rfc-editor.org/info/rfc6347>.
[RFC7049] Bormann, C. and P. Hoffman, "Concise Binary Object
Representation (CBOR)", RFC 7049, DOI 10.17487/RFC7049,
October 2013, <https://www.rfc-editor.org/info/rfc7049>.
[RFC7250] Wouters, P., Ed., Tschofenig, H., Ed., Gilmore, J., [RFC7250] Wouters, P., Ed., Tschofenig, H., Ed., Gilmore, J.,
Weiler, S., and T. Kivinen, "Using Raw Public Keys in Weiler, S., and T. Kivinen, "Using Raw Public Keys in
Transport Layer Security (TLS) and Datagram Transport Transport Layer Security (TLS) and Datagram Transport
Layer Security (DTLS)", RFC 7250, DOI 10.17487/RFC7250, Layer Security (DTLS)", RFC 7250, DOI 10.17487/RFC7250,
June 2014, <https://www.rfc-editor.org/info/rfc7250>. June 2014, <https://www.rfc-editor.org/info/rfc7250>.
[RFC7252] Shelby, Z., Hartke, K., and C. Bormann, "The Constrained [RFC7252] Shelby, Z., Hartke, K., and C. Bormann, "The Constrained
Application Protocol (CoAP)", RFC 7252, Application Protocol (CoAP)", RFC 7252,
DOI 10.17487/RFC7252, June 2014, DOI 10.17487/RFC7252, June 2014,
<https://www.rfc-editor.org/info/rfc7252>. <https://www.rfc-editor.org/info/rfc7252>.
skipping to change at page 81, line 40 skipping to change at page 84, line 25
[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>.
[RFC8085] Eggert, L., Fairhurst, G., and G. Shepherd, "UDP Usage
Guidelines", BCP 145, RFC 8085, DOI 10.17487/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
Writing an IANA Considerations Section in RFCs", BCP 26, Writing an IANA Considerations Section in RFCs", BCP 26,
RFC 8126, DOI 10.17487/RFC8126, June 2017, RFC 8126, DOI 10.17487/RFC8126, June 2017,
<https://www.rfc-editor.org/info/rfc8126>. <https://www.rfc-editor.org/info/rfc8126>.
[RFC8323] Bormann, C., Lemay, S., Tschofenig, H., Hartke, K., [RFC8323] Bormann, C., Lemay, S., Tschofenig, H., Hartke, K.,
Silverajan, B., and B. Raymor, Ed., "CoAP (Constrained Silverajan, B., and B. Raymor, Ed., "CoAP (Constrained
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>.
skipping to change at page 82, line 26 skipping to change at page 85, line 13
2018. 2018.
[I-D.ietf-dots-architecture] [I-D.ietf-dots-architecture]
Mortensen, A., Andreasen, F., Reddy, T., Mortensen, A., Andreasen, F., Reddy, T.,
christopher_gray3@cable.comcast.com, c., Compton, R., and christopher_gray3@cable.comcast.com, c., Compton, R., and
N. Teague, "Distributed-Denial-of-Service Open Threat N. Teague, "Distributed-Denial-of-Service Open Threat
Signaling (DOTS) Architecture", draft-ietf-dots- Signaling (DOTS) Architecture", draft-ietf-dots-
architecture-06 (work in progress), March 2018. architecture-06 (work in progress), March 2018.
[I-D.ietf-dots-data-channel] [I-D.ietf-dots-data-channel]
Reddy, T., Boucadair, M., Nishizuka, K., Xia, L., Patil, Boucadair, M., Reddy, T., Nishizuka, K., Xia, L., Patil,
P., Mortensen, A., and N. Teague, "Distributed Denial-of- P., 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-16 (work in Specification", draft-ietf-dots-data-channel-18 (work in
progress), May 2018. progress), July 2018.
[I-D.ietf-dots-requirements] [I-D.ietf-dots-requirements]
Mortensen, A., Moskowitz, R., and T. Reddy, "Distributed Mortensen, A., Moskowitz, R., and T. Reddy, "Distributed
Denial of Service (DDoS) Open Threat Signaling Denial of Service (DDoS) Open Threat Signaling
Requirements", draft-ietf-dots-requirements-14 (work in Requirements", draft-ietf-dots-requirements-14 (work in
progress), February 2018. progress), February 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-13 (work Open Threat Signaling", draft-ietf-dots-use-cases-16 (work
in progress), June 2018. in progress), July 2018.
[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-dtls13-28 (work in progress), July 1.3", draft-ietf-tls-dtls13-28 (work in progress), July
2018. 2018.
[I-D.ietf-tls-tls13] [I-D.ietf-tls-tls13]
Rescorla, E., "The Transport Layer Security (TLS) Protocol Rescorla, E., "The Transport Layer Security (TLS) Protocol
Version 1.3", draft-ietf-tls-tls13-28 (work in progress), Version 1.3", draft-ietf-tls-tls13-28 (work in progress),
skipping to change at page 84, line 27 skipping to change at page 87, line 9
[RFC5389] Rosenberg, J., Mahy, R., Matthews, P., and D. Wing, [RFC5389] Rosenberg, J., Mahy, R., Matthews, P., and D. Wing,
"Session Traversal Utilities for NAT (STUN)", RFC 5389, "Session Traversal Utilities for NAT (STUN)", RFC 5389,
DOI 10.17487/RFC5389, October 2008, DOI 10.17487/RFC5389, October 2008,
<https://www.rfc-editor.org/info/rfc5389>. <https://www.rfc-editor.org/info/rfc5389>.
[RFC5925] Touch, J., Mankin, A., and R. Bonica, "The TCP [RFC5925] Touch, J., Mankin, A., and R. Bonica, "The TCP
Authentication Option", RFC 5925, DOI 10.17487/RFC5925, Authentication Option", RFC 5925, DOI 10.17487/RFC5925,
June 2010, <https://www.rfc-editor.org/info/rfc5925>. June 2010, <https://www.rfc-editor.org/info/rfc5925>.
[RFC6052] Bao, C., Huitema, C., Bagnulo, M., Boucadair, M., and X.
Li, "IPv6 Addressing of IPv4/IPv6 Translators", RFC 6052,
DOI 10.17487/RFC6052, October 2010,
<https://www.rfc-editor.org/info/rfc6052>.
[RFC6146] Bagnulo, M., Matthews, P., and I. van Beijnum, "Stateful [RFC6146] Bagnulo, M., Matthews, P., and I. van Beijnum, "Stateful
NAT64: Network Address and Protocol Translation from IPv6 NAT64: Network Address and Protocol Translation from IPv6
Clients to IPv4 Servers", RFC 6146, DOI 10.17487/RFC6146, Clients to IPv4 Servers", RFC 6146, DOI 10.17487/RFC6146,
April 2011, <https://www.rfc-editor.org/info/rfc6146>. April 2011, <https://www.rfc-editor.org/info/rfc6146>.
[RFC6234] Eastlake 3rd, D. and T. Hansen, "US Secure Hash Algorithms
(SHA and SHA-based HMAC and HKDF)", RFC 6234,
DOI 10.17487/RFC6234, May 2011,
<https://www.rfc-editor.org/info/rfc6234>.
[RFC6296] Wasserman, M. and F. Baker, "IPv6-to-IPv6 Network Prefix [RFC6296] Wasserman, M. and F. Baker, "IPv6-to-IPv6 Network Prefix
Translation", RFC 6296, DOI 10.17487/RFC6296, June 2011, Translation", RFC 6296, DOI 10.17487/RFC6296, June 2011,
<https://www.rfc-editor.org/info/rfc6296>. <https://www.rfc-editor.org/info/rfc6296>.
[RFC6724] Thaler, D., Ed., Draves, R., Matsumoto, A., and T. Chown, [RFC6724] Thaler, D., Ed., Draves, R., Matsumoto, A., and T. Chown,
"Default Address Selection for Internet Protocol Version 6 "Default Address Selection for Internet Protocol Version 6
(IPv6)", RFC 6724, DOI 10.17487/RFC6724, September 2012, (IPv6)", RFC 6724, DOI 10.17487/RFC6724, September 2012,
<https://www.rfc-editor.org/info/rfc6724>. <https://www.rfc-editor.org/info/rfc6724>.
[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>.
[RFC7049] Bormann, C. and P. Hoffman, "Concise Binary Object
Representation (CBOR)", RFC 7049, DOI 10.17487/RFC7049,
October 2013, <https://www.rfc-editor.org/info/rfc7049>.
[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 85, line 38 skipping to change at page 88, line 25
[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", [RFC7951] Lhotka, L., "JSON Encoding of Data Modeled with YANG",
RFC 7951, DOI 10.17487/RFC7951, August 2016, RFC 7951, DOI 10.17487/RFC7951, August 2016,
<https://www.rfc-editor.org/info/rfc7951>. <https://www.rfc-editor.org/info/rfc7951>.
[RFC8085] Eggert, L., Fairhurst, G., and G. Shepherd, "UDP Usage
Guidelines", BCP 145, RFC 8085, DOI 10.17487/RFC8085,
March 2017, <https://www.rfc-editor.org/info/rfc8085>.
[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>.
Authors' Addresses Authors' Addresses
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