[Docs] [txt|pdf|xml|html] [Tracker] [WG] [Email] [Diff1] [Diff2] [Nits]

Versions: (draft-nishizuka-dots-signal-control-filtering) 00 01

DOTS                                                        K. Nishizuka
Internet-Draft                                        NTT Communications
Intended status: Standards Track                            M. Boucadair
Expires: November 25, 2019                                        Orange
                                                                T. Reddy
                                                                  McAfee
                                                               T. Nagata
                                                                 Lepidum
                                                            May 24, 2019


  Controlling Filtering Rules Using Distributed Denial-of-Service Open
                 Threat Signaling (DOTS) Signal Channel
                draft-ietf-dots-signal-filter-control-01

Abstract

   This document specifies an extension to the DOTS signal channel
   protocol so that DOTS clients can control their filtering rules when
   an attack mitigation is active.

   Particularly, this extension allows a DOTS client to activate or de-
   activate existing filtering rules during a DDoS attack.  The
   characterization of these filtering rules is supposed to be conveyed
   by a DOTS client during an idle time by means of the DOTS data
   channel protocol.

Editorial Note (To be removed by RFC Editor)

   Please update these statements within the document with the RFC
   number to be assigned to this document:

   o  "This version of this YANG module is part of RFC XXXX;"

   o  "RFC XXXX: Controlling Filtering Rules Using Distributed Denial-
      of-Service Open Threat Signaling (DOTS) Signal Channel";

   o  reference: RFC XXXX

   o  [RFCXXXX]

   Please update these statements with the RFC number to be assigned to
   the following documents:

   o  "RFC SSSS: Distributed Denial-of-Service Open Threat Signaling
      (DOTS) Signal Channel Specification" (used to be
      [I-D.ietf-dots-signal-channel])




Nishizuka, et al.       Expires November 25, 2019               [Page 1]


Internet-Draft         DOTS Signal Filter Control               May 2019


   o  "RFC DDDD: Distributed Denial-of-Service Open Threat Signaling
      (DOTS) Data Channel Specification" (used to be
      [I-D.ietf-dots-data-channel])

   Please update the "revision" date of the YANG module.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at https://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on November 25, 2019.

Copyright Notice

   Copyright (c) 2019 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (https://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must
   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  The Problem . . . . . . . . . . . . . . . . . . . . . . .   3
     1.2.  The Solution  . . . . . . . . . . . . . . . . . . . . . .   4
   2.  Terminology . . . . . . . . . . . . . . . . . . . . . . . . .   5
   3.  Controlling Filtering Rules of a DOTS Client  . . . . . . . .   5
     3.1.  Binding DOTS Data and Signal Channels . . . . . . . . . .   5
     3.2.  DOTS Signal Channel Extension . . . . . . . . . . . . . .   6
       3.2.1.  Parameters and Behaviors  . . . . . . . . . . . . . .   6



Nishizuka, et al.       Expires November 25, 2019               [Page 2]


Internet-Draft         DOTS Signal Filter Control               May 2019


       3.2.2.  DOTS Signal Filtering Control Module  . . . . . . . .   9
         3.2.2.1.  Tree Structure  . . . . . . . . . . . . . . . . .   9
         3.2.2.2.  YANG Module . . . . . . . . . . . . . . . . . . .  10
   4.  Sample Examples . . . . . . . . . . . . . . . . . . . . . . .  12
     4.1.  Conflict Handling . . . . . . . . . . . . . . . . . . . .  12
     4.2.  On-Demand Activation of an Accept-List Filter . . . . . .  16
     4.3.  DOTS Servers/Mitigators Lacking Capacity  . . . . . . . .  18
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  22
     5.1.  DOTS Signal Channel CBOR Mappings Registry  . . . . . . .  22
     5.2.  DOTS Signal Filtering Control YANG Module . . . . . . . .  23
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  23
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  24
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  24
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .  24
     8.2.  Informative References  . . . . . . . . . . . . . . . . .  24
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  25

1.  Introduction

1.1.  The Problem

   The DOTS data channel protocol [I-D.ietf-dots-data-channel] is used
   for bulk data exchange between DOTS agents to improve the
   coordination of parties involved in the response to the Distributed
   Denial-of-Service (DDoS) attack.  Filter management is one of its
   tasks which enables a DOTS client to retrieve the filtering
   capabilities of a DOTS server and to manage filtering rules.
   Typically, these Filtering rules are used for dropping or rate-
   limiting unwanted traffic, and permitting accept-listed traffic.

   Unlike the DOTS signal channel protocol
   [I-D.ietf-dots-signal-channel], the DOTS data channel protocol is not
   expected to deal with attack conditions.  As such, an issue that
   might be encountered in some deployments is when filters installed by
   means of the DOTS data channel protocol may not function as expected
   during DDoS attacks or, worse, exacerbate an ongoing DDoS attack.
   The DOTS data channel protocol cannot be used then to change these
   filters, which may complicate DDoS mitigation operations [Interop].

   A typical case is a DOTS client which configures during 'idle' time
   (i.e., no mitigation is active) some filtering rules using the DOTS
   data channel protocol to permit traffic from accept-listed sources,
   but during a volumetric DDoS attack the DDoS mitigator identifies the
   source addresses/prefixes in the accept-listed filtering rules are
   attacking the target.  For example, an attacker can spoof the IP
   addresses of accept-listed sources to generate attack traffic or the
   attacker can compromise the accept-listed sources and program them to
   launch a DDoS attack.



Nishizuka, et al.       Expires November 25, 2019               [Page 3]


Internet-Draft         DOTS Signal Filter Control               May 2019


   [I-D.ietf-dots-signal-channel] is designed so that the DDoS server
   notifies the conflict to the DOTS client (that is, 'conflict-cause'
   parameter set to 2 (Conflicts with an existing accept list)), but the
   DOTS client may not be able to withdraw the accept-list rules during
   the attack period due to the high-volume attack traffic saturating
   the inbound link to the DOTS client domain.  In other words, the DOTS
   client cannot use the DOTS data channel protocol to withdraw the
   accept-list filters when a DDoS attack is in progress.  This assumes
   that this DOTS client is the owner of the filtering rule.

1.2.  The Solution

   This specification addresses the problems discussed in Section 1.1 by
   adding the capability of managing filtering rules using the DOTS
   signal channel protocol, which enables a DOTS client to request the
   activation (or deactivation) of filtering rules during a DDoS attack.

   The DOTS signal channel protocol is designed to enable a DOTS client
   to contact a DOTS server for help even under severe network
   congestion conditions.  Therefore, extending the DOTS signal channel
   protocol to manage the filtering rules during an attack will enhance
   the protection capability offered by DOTS protocols.

      Note: The experiment at the IETF103 hackathon [Interop] showed
      that even when the inbound link is saturated by DDoS attack
      traffic, the DOTS client can signal mitigation requests using the
      DOTS signal channel over the saturated link.

   Conflicts that are induced by filters installed by other DOTS clients
   of the same domain are not discussed in this specification.

   An augment to the DOTS signal channel YANG module is defined in
   Section 3.2.2.

   Sample examples are provided in Section 4, in particular:

   o  Section 4.1 illustrates how the filter control extension is used
      when conflicts with Access Control List (ACLs) are detected and
      reported by a DOTS server.

   o  Section 4.2 shows how a DOTS client can instruct a DOTS server to
      safely forward some specific traffic in 'attack' time.

   o  Section 4.3 shows how a DOTS client can react if the DDoS traffic
      is still being forwarded to the DOTS client domain even if
      mitigation requests were sent to a DOTS server.





Nishizuka, et al.       Expires November 25, 2019               [Page 4]


Internet-Draft         DOTS Signal Filter Control               May 2019


   The JavaScript Object Notation (JSON) encoding of YANG-modeled data
   [RFC7951] is used to illustrate the examples.

2.  Terminology

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in BCP
   14 [RFC2119] [RFC8174] when, and only when, they appear in all
   capitals, as shown here.

   The reader should be familiar with the terms defined in
   [I-D.ietf-dots-requirements].

   The terminology for describing YANG modules is defined in [RFC7950].
   The meaning of the symbols in the tree diagram is defined in
   [RFC8340].

3.  Controlling Filtering Rules of a DOTS Client

3.1.  Binding DOTS Data and Signal Channels

   The filtering rules eventually managed using the DOTS signal channel
   protocol are created a priori by the same DOTS client using the DOTS
   data channel protocol.  Managing conflicts with filters installed by
   other DOTS clients of the same domain is out of scope.

   As discussed in Section 4.4.1 of [I-D.ietf-dots-signal-channel], a
   DOTS client must use the same 'cuid' for both the DOTS signal and
   data channels.  This requirement is meant to facilitate binding DOTS
   channels used by the same DOTS client.

   The DOTS signal and data channels from a DOTS client may or may not
   use the same DOTS server.  Nevertheless, the scope of the mitigation
   request, alias, and filtering rules are not restricted to the DOTS
   server but to the DOTS server domain.  To that aim, DOTS servers
   within a domain are assumed to have a mechanism to coordinate the
   mitigation requests, aliases, and filtering rules to coordinate their
   decisions for better mitigation operation efficiency.  The exact
   details about such mechanism is out of the scope of this document.

   A filtering rule controlled by the DOTS signal channel is identified
   by its ACL name (Section 7.2 of [I-D.ietf-dots-data-channel]).  Note
   that an ACL name unambiguously identifies an ACL bound to a DOTS
   client, but the same name may be used by distinct DOTS clients.

   The activation or deactivation of an ACL by the DOTS signal channel
   overrides the 'activation-type' (defined in Section 7.2 of



Nishizuka, et al.       Expires November 25, 2019               [Page 5]


Internet-Draft         DOTS Signal Filter Control               May 2019


   [I-D.ietf-dots-data-channel]) a priori conveyed with the filtering
   rules using the DOTS data channel protocol.

3.2.  DOTS Signal Channel Extension

3.2.1.  Parameters and Behaviors

   This specification extends the mitigation request defined in
   Section 4.4.1 of [I-D.ietf-dots-signal-channel] to convey the
   intended control of configured filtering rules.  Concretely, the DOTS
   client conveys 'acl-list' attribute with the following sub-attributes
   in the CBOR body of a mitigation request (see the YANG-encoded
   structure in Section 3.2.2.1):

   acl-name:  A name of an access list defined using the DOTS data
      channel (Section 7.2 of [I-D.ietf-dots-data-channel]) that is
      associated with the DOTS client.

      As a reminder, an ACL is an ordered list of Access Control Entries
      (ACE).  Each Access Control Entry has a list of match criteria and
      a list of actions [I-D.ietf-dots-data-channel].  The list of
      configured ACLs can be retrieved using the DOTS data channel
      during 'idle' time.

      This is an optional attribute.

   activation-type:  Indicates the activation type of an ACL overriding
      the existing 'activation-type' installed by the DOTS client using
      the DOTS data channel.

      As a reminder, this attribute can be set to 'deactivate',
      'immediate', or 'activate-when-mitigating' as defined in
      [I-D.ietf-dots-data-channel].

      Note that both 'immediate' and 'activate-when-mitigating' have an
      immediate effect when a mitigation request is being processed by
      the DOTS server.

      This is an optional attribute.

      The JSON/YANG mapping to CBOR for 'activation-type' is shown in
      Table 1.









Nishizuka, et al.       Expires November 25, 2019               [Page 6]


Internet-Draft         DOTS Signal Filter Control               May 2019


   +-------------------+------------+--------+---------------+--------+
   | Parameter Name    | YANG       | CBOR   | CBOR Major    | JSON   |
   |                   | Type       | Key    |    Type &     | Type   |
   |                   |            |        | Information   |        |
   +-------------------+------------+--------+---------------+--------+
   | activation-type   | enumeration| 0x0031 | 0 unsigned    | String |
   |                   |            | (TBD1) |               |        |
   +-------------------+------------+--------+---------------+--------+

         Table 1: JSON/YANG mapping to CBOR for 'activation-type'

   By default, ACL-related operations are achieved using the DOTS data
   channel protocol when no attack is ongoing.  DOTS clients MUST NOT
   use the filtering control over DOTS signal channel in 'idle' time;
   such requests MUST be discarded by DOTS servers with 4.00 (Bad
   Request).

   During an attack time, DOTS clients may include 'acl-list', 'acl-
   name', and 'activation-type' attributes in a mitigation request.
   This request may be the initial mitigation request for a given
   mitigation scope or a new one overriding an existing request.  In
   both cases, a new 'mid' MUST be used.  Nevertheless, it is NOT
   RECOMMENDED to include ACL attributes in an initial mitigation
   request for a given mitigation scope or in a mitigation request
   adjusting the mitigation scope.

   As the attack evolves, DOTS clients can adjust the 'activation-type'
   of an ACL conveyed in a mitigation request or control other filters
   as necessary.  This can be achieved by sending a PUT request with a
   new 'mid' value.

   It is RECOMMENDED for a DOTS client to subscribe to asynchronous
   notifications of the attack mitigation, as detailed in
   Section 4.4.2.1 of [I-D.ietf-dots-signal-channel].  If not, the
   polling mechanism in Section 4.4.2.2 of
   [I-D.ietf-dots-signal-channel] has to be followed by the DOTS client.

   A DOTS client relies on the information received from the DOTS server
   and/or local information to the DOTS client domain to trigger a
   filter control request.  Only filters that are pertinent for an
   ongoing mitigation should be controlled by a DOTS client using the
   DOTS signal channel.

   As a reminder, the 'acl-list' and 'acl-name' parameters are defined
   as comprehension-required parameters in Table 6 of
   [I-D.ietf-dots-signal-channel].  Also, the 'activation-type' is
   defined as a comprehension-required parameter (Section 5.1).
   Following the rules in Section 6 of [I-D.ietf-dots-signal-channel],



Nishizuka, et al.       Expires November 25, 2019               [Page 7]


Internet-Draft         DOTS Signal Filter Control               May 2019


   if the DOTS server does not understand the 'acl-list' or 'acl-name'
   or 'activation-type' attributes, it responds with a "4.00 (Bad
   Request)" error response code.

   If the DOTS server does not find the ACL name ('acl-name') conveyed
   in the mitigation request for this DOTS client, it MUST respond with
   4.04 (Not Found) error response code.

   If the DOTS server finds the ACL name for this DOTS client, and
   assuming the request passed the validation checks in Section 4.4.1 of
   [I-D.ietf-dots-signal-channel], the DOTS server MUST proceed with the
   'activation-type' update.  The update is immediately enforced by the
   DOTS server and will be maintained as the new activation type for the
   ACL name even after the termination of the mitigation request.  In
   addition, the DOTS server MUST update the lifetime of the
   corresponding ACL similar to the update when a refresh request is
   received using the DOTS data channel (Section 7.2 of
   [I-D.ietf-dots-data-channel]).  If, for some reason, the DOTS server
   fails to apply the filter update, it MUST respond with 5.03 (Service
   Unavailable) error response code and include the failed ACL update in
   the diagnostic payload of the response (an example is shown in
   Figure 1).  Else, the DOTS server replies with the appropriate
   response code defined in Section 4.4.1 of
   [I-D.ietf-dots-signal-channel].

   {
     "ietf-dots-signal-channel:mitigation-scope": {
       "scope": [
         {
           "mid": 123,
           "ietf-dots-signal-control:acl-list": [
             {
               "ietf-dots-signal-control:acl-name": "an-accept-list",
               "ietf-dots-signal-control:activation-type": "deactivate"
             }
           ]
         }
       ]
     }
   }

   Figure 1: Example of a Diagnostic Payload Including Failed ACL Update

   If the DOTS client receives a 5.03 (Service Unavailable) with a
   diagnostic payload indicating a failed ACL update as a response to an
   initial mitigation or a mitigation with adjusted scope, the DOTS
   client MUST immediately send a new request which repeats all the
   parameters as sent in the failed mitigation request but without



Nishizuka, et al.       Expires November 25, 2019               [Page 8]


Internet-Draft         DOTS Signal Filter Control               May 2019


   including the ACL attributes.  After the expiry of Max-Age returned
   in the 5.03 (Service Unavailable) response, the DOTS client retries
   with a new mitigation request (i.e., a new 'mid') that repeats all
   the parameters as sent in the failed mitigation request.

   If, during an active mitigation, the 'activation-type' is changed at
   the DOTS server (e.g., as a result of an external action) for an ACL
   bound to a DOTS client, the DOTS server notifies that DOTS client
   with the change by including the corresponding ACL parameters in an
   asynchronous notification (the DOTS client is observing the active
   mitigation) or in a response to a polling request (Section 4.4.2.2 of
   [I-D.ietf-dots-signal-channel]).

   If the DOTS signal and data channels of a DOTS client are not
   established with the same DOTS server of a DOTS server domain, the
   above request processing operations are undertaken using the
   coordination mechanism discussed in Section 3.1.

   This specification does not require any modification to the efficacy
   update and the withdrawal procedures defined in
   [I-D.ietf-dots-signal-channel].  In particular, ACL-related clauses
   are not included in a PUT request used to send an efficacy update and
   DELETE requests.

3.2.2.  DOTS Signal Filtering Control Module

3.2.2.1.  Tree Structure

   This document augments the "ietf-dots-signal-channel" DOTS signal
   YANG module defined in [I-D.ietf-dots-signal-channel] for managing
   filtering rules.

   This document defines the YANG module "ietf-dots-signal-control",
   which has the following tree structure:

   module: ietf-dots-signal-control
     augment /ietf-signal:dots-signal/ietf-signal:message-type
             /ietf-signal:mitigation-scope/ietf-signal:scope:
       +--rw acl-list* [acl-name] {control-filtering}?
          +--rw acl-name
          |    -> /ietf-data:dots-data/dots-client/acls/acl/name
          +--rw activation-type?   ietf-data:activation-type









Nishizuka, et al.       Expires November 25, 2019               [Page 9]


Internet-Draft         DOTS Signal Filter Control               May 2019


3.2.2.2.  YANG Module

   This module uses types defined in [I-D.ietf-dots-data-channel].

   <CODE BEGINS> file "ietf-dots-signal-control@2019-05-13.yang"

   module ietf-dots-signal-control {
     yang-version 1.1;
     namespace
        "urn:ietf:params:xml:ns:yang:ietf-dots-signal-control";
     prefix signal-control;

     import ietf-dots-signal-channel {
       prefix ietf-signal;
       reference
         "RFC SSSS: Distributed Denial-of-Service Open Threat
                    Signaling (DOTS) Signal Channel Specification";
       }
     import ietf-dots-data-channel {
       prefix ietf-data;
       reference
         "RFC DDDD: Distributed Denial-of-Service Open Threat
                    Signaling (DOTS) Data Channel Specification";
     }

     organization
       "IETF DDoS Open Threat Signaling (DOTS) Working Group";
     contact
       "WG Web:   <https://datatracker.ietf.org/wg/dots/>
        WG List:  <mailto:dots@ietf.org>

        Author:  Konda, Tirumaleswar Reddy
                 <mailto:TirumaleswarReddy_Konda@McAfee.com>

        Author:  Mohamed Boucadair
                 <mailto:mohamed.boucadair@orange.com>

        Author:  Kaname Nishizuka
                 <mailto:kaname@nttv6.jp>

        Author:  Takahiko Nagata
                    <mailto:nagata@lepidum.co.jp>";

     description
       "This module contains YANG definition for the signaling
        messages exchanged between a DOTS client and a DOTS server
        to control, by means of the DOTS signal channel, filtering
        rules configured using the DOTS data channel.



Nishizuka, et al.       Expires November 25, 2019              [Page 10]


Internet-Draft         DOTS Signal Filter Control               May 2019


        Copyright (c) 2019 IETF Trust and the persons identified as
        authors of the code.  All rights reserved.

        Redistribution and use in source and binary forms, with or
        without modification, is permitted pursuant to, and subject
        to the license terms contained in, the Simplified BSD License
        set forth in Section 4.c of the IETF Trust's Legal Provisions
        Relating to IETF Documents
        (http://trustee.ietf.org/license-info).

        This version of this YANG module is part of RFC XXXX; see
        the RFC itself for full legal notices.";

     revision 2019-05-13 {
       description
         "Initial revision.";
       reference
         "RFC XXXX: Controlling Filtering Rules Using Distributed
                    Denial-of-Service Open Threat Signaling (DOTS)
                    Signal Channel";
     }

     feature control-filtering {
       description
         "This feature means that the DOTS signal channel is able
          to manage the filtering rules created by the same DOTS
          client using the DOTS data channel.";
     }

     augment "/ietf-signal:dots-signal/ietf-signal:message-type"
           + "/ietf-signal:mitigation-scope/ietf-signal:scope" {
       if-feature control-filtering;

       description "ACL name and activation type.";

       list acl-list {
         key "acl-name";
         description
           "List of ACLs as defined using the DOTS data
            channel. ACLs bound to a DOTS client are uniquely
            identified by a name.";
         leaf acl-name {
           type leafref {
             path "/ietf-data:dots-data/ietf-data:dots-client"
                + "/ietf-data:acls/ietf-data:acl/ietf-data:name";
         }
         description
           "Reference to the ACL name bound to a DOTS client.";



Nishizuka, et al.       Expires November 25, 2019              [Page 11]


Internet-Draft         DOTS Signal Filter Control               May 2019


       }
       leaf activation-type {
         type ietf-data:activation-type;
         default "activate-when-mitigating";
         description
           "Sets the activation type of an ACL.";
         }
       }
     }
   }
   <CODE ENDS>

4.  Sample Examples

   This section provides sample examples to illustrate the behavior
   specified in Section 3.2.1.  These examples are provided for
   illustration purposes; they should not be considered as deployment
   recommendations.

4.1.  Conflict Handling

   Let's consider a DOTS client which contacts its DOTS server during
   'idle' time to install an accept-list allowing for UDP traffic issued
   from 2001:db8:1234::/48 with a destination port number 443 to be
   forwarded to 2001:db8:6401::2/127.  It does so by sending, for
   example, a PUT request shown in Figure 2.

























Nishizuka, et al.       Expires November 25, 2019              [Page 12]


Internet-Draft         DOTS Signal Filter Control               May 2019


   PUT /restconf/data/ietf-dots-data-channel:dots-data\
       /dots-client=paL8p4Zqo4SLv64TLPXrxA/acls\
       /acl=an-accept-list HTTP/1.1
   Host: {host}:{port}
   Content-Type: application/yang-data+json

   {
     "ietf-dots-data-channel:acls": {
       "acl": [
         {
           "name": "an-accept-list",
           "type": "ipv6-acl-type",
           "activation-type": "activate-when-mitigating",
           "aces": {
             "ace": [
               {
                 "name": "test-ace-ipv6-udp",
                 "matches": {
                   "ipv6": {
                     "destination-ipv6-network": "2001:db8:6401::2/127",
                     "source-ipv6-network": "2001:db8:1234::/48"
                   },
                   "udp": {
                     "destination-port": {
                       "operator": "eq",
                       "port": 443
                     }
                   }
                 },
                 "actions": {
                   "forwarding": "accept"
                 }
               }
             ]
           }
         }
       ]
     }
   }

         Figure 2: DOTS Data Channel Request to Create a Filtering

   Some time later, consider that a DDoS attack is detected by the DOTS
   client on 2001:db8:6401::2/127.  Consequently, the DOTS client sends
   a mitigation request to its DOTS server as shown in Figure 3.






Nishizuka, et al.       Expires November 25, 2019              [Page 13]


Internet-Draft         DOTS Signal Filter Control               May 2019


     Header: PUT (Code=0.03)
     Uri-Path: ".well-known"
     Uri-Path: "dots"
     Uri-Path: "mitigate"
     Uri-Path: "cuid=paL8p4Zqo4SLv64TLPXrxA"
     Uri-Path: "mid=123"
     Content-Format: "application/dots+cbor"

     {
       "ietf-dots-signal-channel:mitigation-scope": {
         "scope": [
           {
             "target-prefix": [
                "2001:db8:6401::2/127"
              ],
              "target-protocol": [
                17
              ],
             "lifetime": 3600
           }
         ]
       }
     }

             Figure 3: DOTS Signal Channel Mitigation Request

   The DOTS server accepts immediately the request by replying with 2.01
   (Created) (Figure 4 depicts the message body of the response).

   {
     "ietf-dots-signal-channel:mitigation-scope": {
        "scope": [
           {
             "mid": 123,
             "lifetime": 3600
         }
       ]
     }
   }

                 Figure 4: Status Response (Message Body)

   Assuming the DOTS client subscribed to asynchronous notifications,
   when the DOTS server concludes that some of the attack sources belong
   to 2001:db8:1234::/48, it sends a notification message with 'status'
   code set to '1 (Attack mitigation is in progress)' and 'conflict-
   cause' set to '2' (conflict-with-acceptlist) to the DOTS client to




Nishizuka, et al.       Expires November 25, 2019              [Page 14]


Internet-Draft         DOTS Signal Filter Control               May 2019


   indicate that this mitigation request is in progress, but a conflict
   is detected.

   Upon receipt of the notification message from the DOTS server, the
   DOTS client sends a PUT request to deactivate the "an-accept-list"
   ACL as shown in Figure 5.

   The DOTS client can also decide to send a PUT request to deactivate
   the "an-accept-list" ACL, if suspect traffic is received from an
   accept-listed source (2001:db8:1234::/48).  The structure of that PUT
   is the same as the one shown in Figure 5.

   Header: PUT (Code=0.03)
   Uri-Path: ".well-known"
   Uri-Path: "dots"
   Uri-Path: "mitigate"
   Uri-Path: "cuid=paL8p4Zqo4SLv64TLPXrxA"
   Uri-Path: "mid=124"
   Content-Format: "application/dots+cbor"

   {
     "ietf-dots-signal-channel:mitigation-scope": {
       "scope": [
         {
           "target-prefix": [
              "2001:db8:6401::2/127"
            ],
            "target-protocol": [
              17
            ],
            "ietf-dots-signal-control:acl-list": [
              {
                "ietf-dots-signal-control:acl-name": "an-accept-list",
                "ietf-dots-signal-control:activation-type": "deactivate"
              }
            ]
           "lifetime": 3600
         }
       ]
     }
   }

            Figure 5: PUT for Deactivating a Conflicting Filter

   Then, the DOTS server deactivates "an-accept-list" ACL and replies
   with 2.04 (Changed) response to the DOTS client to confirm the
   successful operation.  The message body is similar to the one
   depicted in Figure 4.



Nishizuka, et al.       Expires November 25, 2019              [Page 15]


Internet-Draft         DOTS Signal Filter Control               May 2019


   Once the attack is mitigated, the DOTS client may use the data
   channel to retrieve its ACLs maintained by the DOTS server.  As shown
   in Figure 6, the activation type is set to 'deactivate' as set by the
   signal channel (Figure 5) instead of the type initially set using the
   data channel (Figure 2).

   {
     "ietf-dots-data-channel:acls": {
       "acl": [
         {
           "name": "an-accept-list",
           "type": "ipv6-acl-type",
           "activation-type": "deactivate",
           "pending-lifetime": 10021,
           "aces": {
             "ace": [
               {
                 "name": "test-ace-ipv6-udp",
                 "matches": {
                   "ipv6": {
                     "destination-ipv6-network": "2001:db8:6401::2/127",
                     "source-ipv6-network": "2001:db8:1234::/48"
                   },
                   "udp": {
                     "destination-port": {
                       "operator": "eq",
                       "port": 443
                     }
                   }
                 },
                 "actions": {
                   "forwarding": "accept"
                 }
               }
             ]
           }
         }
       ]
     }
   }

         Figure 6: DOTS Data Channel GET Response after Mitigation

4.2.  On-Demand Activation of an Accept-List Filter

   Let's consider a DOTS client which contacts its DOTS server during
   'idle' time to install an accept-list allowing for UDP traffic issued
   from 2001:db8:1234::/48 to be forwarded to 2001:db8:6401::2/127.  It



Nishizuka, et al.       Expires November 25, 2019              [Page 16]


Internet-Draft         DOTS Signal Filter Control               May 2019


   does so by sending, for example, a PUT request shown in Figure 7.
   The DOTS server installs this filter with a "deactivated" state.

   PUT /restconf/data/ietf-dots-data-channel:dots-data\
       /dots-client=ioiuLoZqo4SLv64TLPXrxA/acls\
       /acl=my-accept-list HTTP/1.1
   Host: {host}:{port}
   Content-Type: application/yang-data+json

   {
     "ietf-dots-data-channel:acls": {
       "acl": [
         {
           "name": "my-accept-list",
           "type": "ipv6-acl-type",
           "activation-type": "deactivate",
           "aces": {
             "ace": [
               {
                 "name": "an-ace",
                 "matches": {
                   "ipv6": {
                     "destination-ipv6-network": "2001:db8:6401::2/127",
                     "source-ipv6-network": "2001:db8:1234::/48",
                     "protocol": 17
                   }
                 },
                 "actions": {
                   "forwarding": "accept"
                 }
               }
             ]
           }
         }
       ]
     }
   }

    Figure 7: DOTS Data Channel Request to Create an Accept-List Filter

   Sometime later, consider that a UDP DDoS attack is detected by the
   DOTS client on 2001:db8:6401::2/127 but the DOTS client wants to let
   the traffic from 2001:db8:1234::/48 to be accept-listed to the DOTS
   client domain.  Consequently, the DOTS client sends a mitigation
   request to its DOTS server as shown in Figure 8.






Nishizuka, et al.       Expires November 25, 2019              [Page 17]


Internet-Draft         DOTS Signal Filter Control               May 2019


    Header: PUT (Code=0.03)
    Uri-Path: ".well-known"
    Uri-Path: "dots"
    Uri-Path: "mitigate"
    Uri-Path: "cuid=ioiuLoZqo4SLv64TLPXrxA"
    Uri-Path: "mid=4879"
    Content-Format: "application/dots+cbor"

    {
      "ietf-dots-signal-channel:mitigation-scope": {
        "scope": [
          {
            "target-prefix": [
               "2001:db8:6401::2/127"
             ],
             "target-protocol": [
               17
             ],
             "ietf-dots-signal-control:acl-list": [
               {
                 "ietf-dots-signal-control:acl-name": "my-accept-list",
                 "ietf-dots-signal-control:activation-type": "immediate"
               }
            "lifetime": 3600
          }
        ]
      }
    }

      Figure 8: DOTS Signal Channel Mitigation Request with a Filter
                                  Control

   The DOTS server activates "my-accept-list" ACL and replies with 2.01
   (Created) response to the DOTS client to confirm the successful
   operation.

4.3.  DOTS Servers/Mitigators Lacking Capacity

   This section describes a scenario in which a DOTS client activates a
   drop-list or a rate-limit filter during an attack.

   Consider a DOTS client that contacts its DOTS server during 'idle'
   time to install an accept-list that rate-limits all (or a part
   thereof) traffic to be forwarded to 2001:db8:123::/48 as a last
   resort countermeasure whenever required.  It does so by sending, for
   example, a PUT request shown in Figure 9.  The DOTS server installs
   this filter with a "deactivated" state.




Nishizuka, et al.       Expires November 25, 2019              [Page 18]


Internet-Draft         DOTS Signal Filter Control               May 2019


   PUT /restconf/data/ietf-dots-data-channel:dots-data\
       /dots-client=OopPisZqo4SLv64TLPXrxA/acls\
       /acl=my-ratelimit-list HTTP/1.1
   Host: {host}:{port}
   Content-Type: application/yang-data+json

   {
     "ietf-dots-data-channel:acls": {
       "acl": [
         {
           "name": "my-ratelimit-list",
           "type": "ipv6-acl-type",
           "activation-type": "deactivate",
           "aces": {
             "ace": [
               {
                 "name": "my-ace",
                 "matches": {
                   "ipv6": {
                     "destination-ipv6-network": "2001:db8:123::/48"
                   }
                 },
                 "actions": {
                   "forwarding": "accept",
                   "rate-limit": "20.00"
                 }
               }
             ]
           }
         }
       ]
     }
   }

     Figure 9: DOTS Data Channel Request to Create a Rate-Limit Filter

   Consider now that a DDoS attack is detected by the DOTS client on
   2001:db8:123::/48.  Consequently, the DOTS client sends a mitigation
   request to its DOTS server (Figure 10).












Nishizuka, et al.       Expires November 25, 2019              [Page 19]


Internet-Draft         DOTS Signal Filter Control               May 2019


     Header: PUT (Code=0.03)
     Uri-Path: ".well-known"
     Uri-Path: "dots"
     Uri-Path: "mitigate"
     Uri-Path: "cuid=OopPisZqo4SLv64TLPXrxA"
     Uri-Path: "mid=85"
     Content-Format: "application/dots+cbor"

     {
       "ietf-dots-signal-channel:mitigation-scope": {
         "scope": [
           {
             "target-prefix": [
                "2001:db8:123::/48"
              ],
             "lifetime": 3600
           }
         ]
       }
     }

   Figure 10: DOTS Signal Channel Mitigation Request to Activate a Rate-
                               Limit Filter

   For some reason (e.g., the DOTS server, or the mitigator, is lacking
   a capability or capacity), the DOTS client is still receiving the
   attack trafic which saturates available links.  To soften the
   problem, the DOTS client decides to activate the filter that rate-
   limits the traffic destined to the DOTS client domain.  To that aim,
   the DOTS client sends the mitigation request to its DOTS server shown
   in Figure 11.




















Nishizuka, et al.       Expires November 25, 2019              [Page 20]


Internet-Draft         DOTS Signal Filter Control               May 2019


  Header: PUT (Code=0.03)
  Uri-Path: ".well-known"
  Uri-Path: "dots"
  Uri-Path: "mitigate"
  Uri-Path: "cuid=OopPisZqo4SLv64TLPXrxA"
  Uri-Path: "mid=86"
  Content-Format: "application/dots+cbor"

  {
    "ietf-dots-signal-channel:mitigation-scope": {
      "scope": [
        {
          "target-prefix": [
             "2001:db8:123::/48"
           ],
           "ietf-dots-signal-control:acl-list": [
             {
               "ietf-dots-signal-control:acl-name": "my-ratelimit-list",
               "ietf-dots-signal-control:activation-type": "immediate"
             }
           ]
          "lifetime": 3600
        }
      ]
    }
  }

   Figure 11: DOTS Signal Channel Mitigation Request to Activate a Rate-
                               Limit Filter

   Then, the DOTS server activates "my-ratelimit-list" ACL and replies
   with 2.04 (Changed) response to the DOTS client to confirm the
   successful operation.

   As the attack mitigation evolves, the DOTS client may decide to
   deactivate the rate-limit policy (e.g., upon receipt of notification
   status change from 'attack-exceeded-capability' to 'attack-
   mitigation-in-progress').  Based on the mitigation status conveyed by
   the DOTS server, the DOTS client can de-activate the rate-limit
   action. ).  It does so by sending the request shown in Figure 12.











Nishizuka, et al.       Expires November 25, 2019              [Page 21]


Internet-Draft         DOTS Signal Filter Control               May 2019


  Header: PUT (Code=0.03)
  Uri-Path: ".well-known"
  Uri-Path: "dots"
  Uri-Path: "mitigate"
  Uri-Path: "cuid=OopPisZqo4SLv64TLPXrxA"
  Uri-Path: "mid=87"
  Content-Format: "application/dots+cbor"

  {
    "ietf-dots-signal-channel:mitigation-scope": {
      "scope": [
        {
          "target-prefix": [
             "2001:db8:123::/48"
           ],
           "ietf-dots-signal-control:acl-list": [
             {
               "ietf-dots-signal-control:acl-name": "my-ratelimit-list",
               "ietf-dots-signal-control:activation-type": "deactivate"
             }
           ]
          "lifetime": 3600
        }
      ]
    }
  }

     Figure 12: DOTS Signal Channel Mitigation Request to Deactivate a
                             Rate-Limit Filter

5.  IANA Considerations

5.1.  DOTS Signal Channel CBOR Mappings Registry

   This specification registers the 'activation-type' parameter in the
   IANA "DOTS Signal Channel CBOR Key Values" registry established by
   [I-D.ietf-dots-signal-channel].

   o  Note to the RFC Editor: Please delete (TBD1) once the CBOR key is
      assigned from the (0x0001 - 0x3FFF) range.











Nishizuka, et al.       Expires November 25, 2019              [Page 22]


Internet-Draft         DOTS Signal Filter Control               May 2019


    +--------------------+--------+-------+------------+---------------+
    | Parameter Name     | CBOR   | CBOR  | Change     | Specification |
    |                    | Key    | Major | Controller | Document(s)   |
    |                    | Value  | Type  |            |               |
    +--------------------+--------+-------+------------+---------------+
    |  activation-type   | 0x0031 |   0   |    IESG    |   [RFCXXXX]   |
    |                    | (TBD1) |       |            |               |
    +--------------------+--------+-------+------------+---------------+

5.2.  DOTS Signal Filtering Control YANG Module

   This document requests IANA to register the following URI in the
   "IETF XML Registry" [RFC3688]:

     URI: urn:ietf:params:xml:ns:yang:ietf-dots-signal-control
     Registrant Contact: The IESG.
     XML: N/A; the requested URI is an XML namespace.


   This document requests IANA to register the following YANG module in
   the "YANG Module Names" registry [RFC7950].

     Name: ietf-dots-signal-control
     Namespace: urn:ietf:params:xml:ns:yang:ietf-dots-signal-control
     Maintained by IANA: N
     Prefix: signal-control
     Reference: RFC XXXX


6.  Security Considerations

   The security considerations discussed in
   [I-D.ietf-dots-signal-channel] and [I-D.ietf-dots-data-channel] need
   to be taken into account.

   A DOTS client is entitled to access only to resources it creates.  In
   particular, a DOTS client can not tweak filtering rules created by
   other DOTS clients of the same DOTS client domain.

   A compromised DOTS client can use the filtering control capability to
   exacerbate an ongoing attack.  Likewise, such compromised DOTS client
   may abstain from reacting to an ACL conflict notification received
   from the DOTS server during attacks.  These are not new attack
   vectors, but variations of threats discussed in
   [I-D.ietf-dots-signal-channel] and [I-D.ietf-dots-data-channel].
   DOTS operators should carefully monitor and audit DOTS agents to
   detect misbehaviors and to deter misuses.




Nishizuka, et al.       Expires November 25, 2019              [Page 23]


Internet-Draft         DOTS Signal Filter Control               May 2019


7.  Acknowledgements

   Many thanks to Takahiko Nagata, Wei Pan, Xia Liang, Jon Shallow, and
   Dan Wing for the comments.

8.  References

8.1.  Normative References

   [I-D.ietf-dots-data-channel]
              Boucadair, M. and R. K, "Distributed Denial-of-Service
              Open Threat Signaling (DOTS) Data Channel Specification",
              draft-ietf-dots-data-channel-29 (work in progress), May
              2019.

   [I-D.ietf-dots-signal-channel]
              K, R., Boucadair, M., Patil, P., Mortensen, A., and N.
              Teague, "Distributed Denial-of-Service Open Threat
              Signaling (DOTS) Signal Channel Specification", draft-
              ietf-dots-signal-channel-34 (work in progress), May 2019.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <https://www.rfc-editor.org/info/rfc2119>.

   [RFC3688]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
              DOI 10.17487/RFC3688, January 2004,
              <https://www.rfc-editor.org/info/rfc3688>.

   [RFC7950]  Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language",
              RFC 7950, DOI 10.17487/RFC7950, August 2016,
              <https://www.rfc-editor.org/info/rfc7950>.

   [RFC8174]  Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
              2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
              May 2017, <https://www.rfc-editor.org/info/rfc8174>.

8.2.  Informative References

   [I-D.ietf-dots-requirements]
              Mortensen, A., K, R., and R. Moskowitz, "Distributed
              Denial of Service (DDoS) Open Threat Signaling
              Requirements", draft-ietf-dots-requirements-22 (work in
              progress), March 2019.






Nishizuka, et al.       Expires November 25, 2019              [Page 24]


Internet-Draft         DOTS Signal Filter Control               May 2019


   [Interop]  Nishizuka, K., Shallow, J., and L. Xia , "DOTS Interop
              test report, IETF 103 Hackathon", November 2018,
              <https://datatracker.ietf.org/meeting/103/materials/
              slides-103-dots-interop-report-from-ietf-103-hackathon-
              00>.

   [RFC7951]  Lhotka, L., "JSON Encoding of Data Modeled with YANG",
              RFC 7951, DOI 10.17487/RFC7951, August 2016,
              <https://www.rfc-editor.org/info/rfc7951>.

   [RFC8340]  Bjorklund, M. and L. Berger, Ed., "YANG Tree Diagrams",
              BCP 215, RFC 8340, DOI 10.17487/RFC8340, March 2018,
              <https://www.rfc-editor.org/info/rfc8340>.

Authors' Addresses

   Kaname Nishizuka
   NTT Communications
   GranPark 16F 3-4-1 Shibaura, Minato-ku
   Tokyo  108-8118
   Japan

   Email: kaname@nttv6.jp


   Mohamed Boucadair
   Orange
   Rennes  35000
   France

   Email: mohamed.boucadair@orange.com


   Tirumaleswar Reddy
   McAfee, Inc.
   Embassy Golf Link Business Park
   Bangalore, Karnataka  560071
   India

   Email: kondtir@gmail.com


   Takahiko Nagata
   Lepidum
   Japan

   Email: nagata@lepidum.co.jp




Nishizuka, et al.       Expires November 25, 2019              [Page 25]


Html markup produced by rfcmarkup 1.129c, available from https://tools.ietf.org/tools/rfcmarkup/