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

Versions: 00 01 02 03 04 05 06 draft-ietf-dots-signal-filter-control

DOTS                                                        K. Nishizuka
Internet-Draft                                        NTT Communications
Intended status: Standards Track                            M. Boucadair
Expires: October 4, 2019                                          Orange
                                                                T. Reddy
                                                                  McAfee
                                                               T. Nagata
                                                                 Lepidum
                                                           April 2, 2019


  Controlling Filtering Rules Using Distributed Denial-of-Service Open
                 Threat Signaling (DOTS) Signal Channel
            draft-nishizuka-dots-signal-control-filtering-06

Abstract

   This document specifies an extension to the DOTS signal channel 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 October 4, 2019                [Page 1]


Internet-Draft         DOTS Signal Filter Control             April 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 October 4, 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.  Notational Conventions and Terminology  . . . . . . . . . . .   5
   3.  Controlling Filtering Rules of a DOTS Client  . . . . . . . .   5
     3.1.  Binding the Data and Signal Channels  . . . . . . . . . .   5
     3.2.  DOTS Signal Channel Extension . . . . . . . . . . . . . .   6
       3.2.1.  Parameters & Behaviors  . . . . . . . . . . . . . . .   6



Nishizuka, et al.        Expires October 4, 2019                [Page 2]


Internet-Draft         DOTS Signal Filter Control             April 2019


       3.2.2.  DOTS Signal Filtering Control Module  . . . . . . . .   8
         3.2.2.1.  Tree Structure  . . . . . . . . . . . . . . . . .   8
         3.2.2.2.  YANG Module . . . . . . . . . . . . . . . . . . .   8
   4.  Sample Examples . . . . . . . . . . . . . . . . . . . . . . .  11
     4.1.  Conflict Handling . . . . . . . . . . . . . . . . . . . .  11
     4.2.  On-Demand Activation of an Accept-List Filter . . . . . .  15
     4.3.  DOTS Servers/Mitigators Lacking Capacity  . . . . . . . .  17
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .  20
     5.1.  DOTS Signal Channel CBOR Mappings Registry  . . . . . . .  20
     5.2.  DOTS Signal Filtering Control YANG Module . . . . . . . .  21
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .  21
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  22
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  22
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .  22
     8.2.  Informative References  . . . . . . . . . . . . . . . . .  22
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  23

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 all the parties involved in the response to the 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.  These Filtering rules are used for dropping
   or rate-limiting unwanted traffic, and permitting accept-listed
   traffic.

   Unlike the DOTS signal channel [I-D.ietf-dots-signal-channel], the
   DOTS data channel 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 DOTS data channel protocol may not
   function as expected during DDoS attacks or exacerbate an ongoing
   DDoS attack.  The DOTS data channel 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 DOTS data
   channel 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 October 4, 2019                [Page 3]


Internet-Draft         DOTS Signal Filter Control             April 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.  In other words, the DOTS client cannot use the
   DOTS data channel to withdraw the accept-list filters when the 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, which enables a DOTS client to request the activation
   or deactivation of filtering rules during a DDoS attack.

   The DOTS signal channel protocol [I-D.ietf-dots-signal-channel] 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 a attack will enhance the protection capability offered
   by DOTS protocols.

      Note: The experiment at the IETF103 hackathon [Interop] showed
      that even when the incoming 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.

   Sample examples are provided in Section 4, in particular:

   o  Section 4.1 illustrates how the filter control extension is used
      when conflicts with ACLs are detected 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 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 October 4, 2019                [Page 4]


Internet-Draft         DOTS Signal Filter Control             April 2019


2.  Notational Conventions and 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 meaning of the symbols in tree diagrams is defined in [RFC8340].

3.  Controlling Filtering Rules of a DOTS Client

3.1.  Binding the Data and Signal Channels

   The filtering rules eventually managed using the DOTS signal channel
   are created a priori by the same DOTS client using the DOTS data
   channel.  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 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 scope of this document.

   A filtering rule controlled by the DOTS signal channel is identified
   by its Access Control List (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 signal channel
   overrides the 'activation-type' (defined in Section 7.2 of
   [I-D.ietf-dots-data-channel]) a priori conveyed with the filtering
   rules using the DOTS data channel.





Nishizuka, et al.        Expires October 4, 2019                [Page 5]


Internet-Draft         DOTS Signal Filter Control             April 2019


3.2.  DOTS Signal Channel Extension

3.2.1.  Parameters & 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 the configured filtering rules.  Concretely, the
   DOTS client conveys the following parameters in the CBOR body of a
   mitigation request:

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

      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.

      This attribute can be set to 'deactivate', 'immediate', or
      'activate-when-mitigating' defined [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.

      If this attribute is not provided, the DOTS server MUST use
      'activate-when-mitigating' as the default value.

      This is an optional attribute.

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












Nishizuka, et al.        Expires October 4, 2019                [Page 6]


Internet-Draft         DOTS Signal Filter Control             April 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'

   A DOTS client may include acl-* attributes in a mitigation request
   having a new or an existing 'mid'.  When acl-* attributes are to be
   included in a mitigation request with an existing 'mid', the DOTS
   client MUST repeat all the other parameters as sent in the original
   mitigation request (i.e., having that 'mid') apart from a possible
   change to the lifetime parameter 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 MUST NOT use the filtering control over DOTS signal
   channel in 'idle' time; such requests MUST be discarded by the DOTS
   server with 4.00 (Bad Request).  By default, ACL-related operations
   are achieved using the DOTS data channel [I-D.ietf-dots-data-channel]
   when no attack is ongoing.

   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.

   If the DOTS server does not find the ACL name conveyed in the
   mitigation request in its configuration data for this DOTS client, it
   MUST respond with a "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
   [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




Nishizuka, et al.        Expires October 4, 2019                [Page 7]


Internet-Draft         DOTS Signal Filter Control             April 2019


   corresponding ACL similar to the update when a refresh request is
   received using the DOTS data channel.

   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]).

   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


3.2.2.2.  YANG Module

   <CODE BEGINS> file "ietf-dots-signal-control@2019-04-01.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 {



Nishizuka, et al.        Expires October 4, 2019                [Page 8]


Internet-Draft         DOTS Signal Filter Control             April 2019


       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.

        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.";



Nishizuka, et al.        Expires October 4, 2019                [Page 9]


Internet-Draft         DOTS Signal Filter Control             April 2019


     revision 2019-04-01 {
       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 in the DOTS data
            channel.  These ACLs are uniquely defined by
            cuid and 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.";
       }
       leaf activation-type {
         type ietf-data:activation-type;
         default "activate-when-mitigating";
         description
           "Set the activation type of an ACL.";
         }
       }
     }
   }
   <CODE ENDS>





Nishizuka, et al.        Expires October 4, 2019               [Page 10]


Internet-Draft         DOTS Signal Filter Control             April 2019


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 1.





































Nishizuka, et al.        Expires October 4, 2019               [Page 11]


Internet-Draft         DOTS Signal Filter Control             April 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 1: 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 2.







Nishizuka, et al.        Expires October 4, 2019               [Page 12]


Internet-Draft         DOTS Signal Filter Control             April 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 2: DOTS Signal Channel Mitigation Request

   The DOTS server accepts immediately the request by replying with 2.01
   (Created) (Figure 3).

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

                 Figure 3: 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
   indicate that this mitigation request is in progress, but a conflict
   is detected.



Nishizuka, et al.        Expires October 4, 2019               [Page 13]


Internet-Draft         DOTS Signal Filter Control             April 2019


   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 4.

   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 4.

     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
              ],
              "acl-list": [
                {
                  "acl-name": "an-accept-list",
                  "activation-type": "deactivate"
                }
              ]
             "lifetime": 3600
           }
         ]
       }
     }

            Figure 4: 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 3.

   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 5, the activation type is set to 'deactivate' as set by the



Nishizuka, et al.        Expires October 4, 2019               [Page 14]


Internet-Draft         DOTS Signal Filter Control             April 2019


   signal channel (Figure 4) instead of the type initially set using the
   data channel (Figure 1).

   {
     "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 5: GET to Retrieve the Filtering (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
   does so by sending, for example, a PUT request shown in Figure 6.
   The DOTS server installs this filter with a "deactivated" state.




Nishizuka, et al.        Expires October 4, 2019               [Page 15]


Internet-Draft         DOTS Signal Filter Control             April 2019


   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 6: DOTS Data Channel Request to Create an Accep-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 7.










Nishizuka, et al.        Expires October 4, 2019               [Page 16]


Internet-Draft         DOTS Signal Filter Control             April 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
              ],
              "acl-list": [
                {
                  "acl-name": "my-accept-list",
                  "activation-type": "immediate"
                }
             "lifetime": 3600
           }
         ]
       }
     }

      Figure 7: 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 8.  The DOTS server installs
   this filter with a "deactivated" state.





Nishizuka, et al.        Expires October 4, 2019               [Page 17]


Internet-Draft         DOTS Signal Filter Control             April 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 8: 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 9).













Nishizuka, et al.        Expires October 4, 2019               [Page 18]


Internet-Draft         DOTS Signal Filter Control             April 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 9: 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 10.





















Nishizuka, et al.        Expires October 4, 2019               [Page 19]


Internet-Draft         DOTS Signal Filter Control             April 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"
              ],
              "acl-list": [
                {
                  "acl-name": "my-ratelimit-list",
                  "activation-type": "activate"
                }
              ]
             "lifetime": 3600
           }
         ]
       }
     }

   Figure 10: 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.

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].

   The 'activation-type' is a comprehension-required parameter.  The
   'acl-list' and 'acl-name' parameters are defined as comprehension-
   required parameters in Table 6 in [I-D.ietf-dots-signal-channel].
   Following the rules in [I-D.ietf-dots-signal-channel], 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.



Nishizuka, et al.        Expires October 4, 2019               [Page 20]


Internet-Draft         DOTS Signal Filter Control             April 2019


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

    +--------------------+--------+-------+------------+---------------+
    | 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 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 misbehavior and to deter misuse.





Nishizuka, et al.        Expires October 4, 2019               [Page 21]


Internet-Draft         DOTS Signal Filter Control             April 2019


7.  Acknowledgements

   Thank you to Takahiko Nagata, Wei Pan, Xia Liang, and Jon Shollow 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-27 (work in progress),
              February 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-30 (work in progress), March
              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 October 4, 2019               [Page 22]


Internet-Draft         DOTS Signal Filter Control             April 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>.

   [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 October 4, 2019               [Page 23]


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