| DOTS | T. Reddy, Ed. |
| Internet-Draft | McAfee |
| Intended status: Standards Track | M. Boucadair, Ed. |
| Expires: July 15, 2018 | Orange |
| K. Nishizuka | |
| NTT Communications | |
| L. Xia | |
| Huawei | |
| P. Patil | |
| Cisco | |
| A. Mortensen | |
| Arbor Networks, Inc. | |
| N. Teague | |
| Verisign, Inc. | |
| January 11, 2018 |
Distributed Denial-of-Service Open Threat Signaling (DOTS) Data Channel
draft-ietf-dots-data-channel-12
The document specifies a Distributed Denial-of-Service Open Threat Signaling (DOTS) data channel used for bulk exchange of data that cannot easily or appropriately communicated through the DOTS signal channel under attack conditions.
This is a companion document to the DOTS signal channel specification.
Please update these statements with the RFC number to be assigned to this document:
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 July 15, 2018.
Copyright (c) 2018 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.
A distributed denial-of-service (DDoS) attack is an attempt to make machines or network resources unavailable to their intended users. In most cases, sufficient scale can be achieved by compromising enough end-hosts and using those infected hosts to perpetrate and amplify the attack. The victim of such attack can be an application server, a router, a firewall, an entire network, etc.
+---------------+ +---------------+ | | <------- Signal Channel ------> | | | DOTS Client | | DOTS Server | | | <======= Data Channel ======> | | +---------------+ +---------------+
Figure 1: DOTS Channels
As discussed in [I-D.ietf-dots-requirements], the lack of a common method to coordinate a real-time response among involved actors and network domains inhibits the speed and effectiveness of DDoS attack mitigation. From that standpoint, DDoS Open Threat Signaling (DOTS) [I-D.ietf-dots-architecture] defines an architecture that allows a DOTS client to send requests to a DOTS server for DDoS attack mitigation. The DOTS approach is thus meant to minimize the impact of DDoS attacks, thereby contributing to the enforcement of more efficient defensive if not proactive security strategies. To that aim, DOTS defines two channels: the signal and the data channels (Figure 1).
The DOTS signal channel is used to carry information about a device or a network (or a part thereof) that is under a DDoS attack. Such information is sent by a DOTS client to an upstream DOTS server so that appropriate mitigation actions are undertaken on traffic deemed suspicious. The DOTS signal channel is further elaborated in [I-D.ietf-dots-signal-channel].
As for the DOTS data channel, it is used for infrequent bulk data exchange between DOTS agents to significantly improve the coordination of all the parties involved in the response to the attack. Section 2 of [I-D.ietf-dots-architecture] mentions that the DOTS data channel is used to perform the following tasks:
Refer to
Section 7 for more details.The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119].
The reader should be familiar with the terms defined in [I-D.ietf-dots-architecture].
The terminology for describing YANG data modules is defined in [RFC7950]. The meaning of the symbols in tree diagrams is defined in [I-D.ietf-netmod-yang-tree-diagrams].
For the sake of simplicity, all of the examples in this document use "/restconf" as the discovered RESTCONF API root path. Many protocol header lines and message-body text within examples throughout the document are split into multiple lines for display purposes only. When a line ends with backslash ('\') as the last character, the line is wrapped for display purposes. It is to be considered to be joined to the next line by deleting the backslash, the following line break, and the leading whitespace of the next line.
Unlike the DOTS signal channel [I-D.ietf-dots-signal-channel], which must remain operational even when confronted with signal degradation due to packets loss, the DOTS data channel is not expected to be fully operational at all times, especially when a DDoS attack is underway. The requirements for a DOTS data channel protocol are documented in [I-D.ietf-dots-requirements].
This specification does not require an order of DOTS signal and data channel creations nor mandates a time interval between them. These considerations are implementation- and deployment-specific.
As the primary function of the data channel is data exchange, a reliable transport mode is required in order for DOTS agents to detect data delivery success or failure. This document uses RESTCONF [RFC8040] over TLS [RFC5246] over TCP as the DOTS data channel protocol (Figure 2).
+-------------------+ | DOTS Data Channel | +-------------------+ | RESTCONF | +-------------------+ | TLS | +-------------------+ | TCP | +-------------------+ | IP | +-------------------+
Figure 2: Abstract Layering of DOTS Data Channel over RESTCONF over TLS
The HTTP POST, PUT, PATCH, and DELETE methods are used to edit data resources represented by DOTS data channel YANG data modules. These basic edit operations allow the DOTS data channel running configuration to be altered by a DOTS client.
DOTS data channel configuration information as well as state information can be retrieved with the GET method. An HTTP status-line header field is returned for each request to report success or failure for RESTCONF operations (Section 5.4 of [RFC8040]).
The DOTS client performs the root resource discovery procedure discussed in Section 3.1 of [RFC8040] to determine the root of the RESTCONF API. After discovering the RESTCONF API root, the DOTS client uses this value as the initial part of the path in the request URI, in any subsequent request to the DOTS server. The DOTS server may support the retrieval of the YANG modules it supports (Section 3.7 in [RFC8040]). For example, a DOTS client may use RESTCONF to retrieve the vendor-specific YANG modules supported by the DOTS server.
JavaScript Object Notation (JSON) [RFC7159] payload is used to propagate the DOTS data channel specific payload messages that carry request parameters and response information, such as errors. This specification uses the encoding rules defined in [RFC7951] for representing DOTS data channel configuration data using YANG (Section 5) as JSON text.
A DOTS client registers itself to its DOTS server(s) in order to set up DOTS data channel-related configuration data and receive state data (i.e., non-configuration data) from the DOTS server(s).
A single DOTS data channel between DOTS agents can be used to exchange multiple requests and multiple responses. To reduce DOTS client and DOTS server workload, DOTS client SHOULD re-use the same TLS session. While the communication to the DOTS server is quiescent, the DOTS client MAY probe the server to ensure it has maintained cryptographic state. Such probes can also keep alive firewall and/or NAT bindings. A TLS heartbeat [RFC6520] verifies that the DOTS server still has TLS state by returning a TLS message.
In deployments where one or more translators (e.g., NAT44, NAT64, NPTv6) are enabled between the client's network and the DOTS server, DOTS data channel messages forwarded to a DOTS server must not include internal IP addresses/prefixes and/or port numbers; external addresses/prefixes and/or port numbers as assigned by the translator must be used instead. This document does not make any recommendation about possible translator discovery mechanisms. The following are some (non-exhaustive) deployment examples that may be considered:
When a server-domain DOTS gateway is involved in DOTS data channel exchanges, the same considerations for manipulating the 'client-domain-hash' parameter as specified in [I-D.ietf-dots-signal-channel] MUST be followed by DOTS agents.
A DOTS server may detect conflicting filtering requests from the same or distinct DOTS clients which belong to the same domain. For example, a DOTS client would request to blacklist a prefix, while another DOTS client would request to whitelist that same prefix. It is out of scope of this specification to recommend the behavior to follow for handling conflicting requests (e.g., reject all, reject the new request, notify an administrator for validation). DOTS servers SHOULD support a configuration parameter to indicate the behavior to follow when a conflict is detected. Section 7.1 specifies the behavior when no instruction is supplied to a DOTS server.
This document assumes that DOTS clients are provisioned with the reachability information of their DOTS server(s) using a variety of means (e.g., local configuration, or dynamic means such as DHCP). The specification of such means are out of scope of this document.
Likewise, it is out of scope of this document to specify the behavior to follow by a DOTS client to place its requests (e.g., contact all servers, select one server among the list) when multiple DOTS servers are provisioned.
The YANG module (ietf-dots-data-channel) allows to create aliases, for resources for which mitigation may be requested. Such aliases may be used in subsequent DOTS signal channel exchanges to refer more efficiently to the resources under attack. The tree structure for DOTS aliases is as follows:
+--rw aliases
+--rw dots-client* [cuid]
+--rw cuid string
+--rw client-domain-hash? string
+--rw alias* [alias-name]
+--rw alias-name string
+--rw target-prefix* inet:ip-prefix
+--rw target-port-range* [lower-port upper-port]
| +--rw lower-port inet:port-number
| +--rw upper-port inet:port-number
+--rw target-protocol* uint8
+--rw target-fqdn* inet:domain-name
+--rw target-uri* inet:uri
[I-D.ietf-dots-signal-channel].
This document augments the Access Control List (ACL) YANG module [I-D.ietf-netmod-acl-model] for managing DOTS filtering rules. The notion of ACL is explained in Section 1 of [I-D.ietf-netmod-acl-model].
Examples of ACL management in a DOTS context include, but not limited to:
DOTS implementations MUST support the following features defined in [I-D.ietf-netmod-acl-model]:
Given that DOTS data channel does not deal with interfaces, the support of the "ietf-interfaces" module [RFC7223] and its augmentation in the "ietf-access-control-list" module are not required for DOTS. Specifically, the support of interface-related features and branches (e.g., interface-attachment, interface-stats, acl-aggregate-stats, and interface-acl-aggregate) of the ACL YANG module is not required.
The following forwarding actions MUST be supported:
The support of 'reject' action is NOT RECOMMENDED because it is not appropriate in the context of DDoS mitigation. Generating ICMP messages to notify drops when mitigating a DDoS attack will exacerbate the DDoS attack. Further, it will be used by an attacker as an explicit signal that the traffic is being blocked.
The following tree structure provides the excerpt of the "ietf-access-control-list" module to be supported by DOTS implementations.
+--rw access-lists
+--rw acl* [name]
| +--rw name string
| +--rw acl-type? acl-type
| +--rw aces
| +--rw ace* [rule-name]
| +--rw rule-name string
| +--rw matches
| | +--rw (l3)?
| | | +--:(ipv4)
| | | | +--rw ipv4 {match-on-ipv4}?
| | | | +--rw dscp? inet:dscp
| | | | +--rw ecn? uint8
| | | | +--rw length? uint16
| | | | +--rw ttl? uint8
| | | | +--rw protocol? uint8
| | | | +--rw source-port-range!
| | | | | +--rw lower-port inet:port-number
| | | | | +--rw upper-port? inet:port-number
| | | | | +--rw operation? operator
| | | | +--rw destination-port-range!
| | | | | +--rw lower-port inet:port-number
| | | | | +--rw upper-port? inet:port-number
| | | | | +--rw operations? operator
| | | | +--rw ihl? uint8
| | | | +--rw flags? bits
| | | | +--rw offset? uint16
| | | | +--rw identification? uint16
| | | | +--rw destination-ipv4-network? inet:ipv4-prefix
| | | | +--rw source-ipv4-network? inet:ipv4-prefix
| | | +--:(ipv6)
| | | +--rw ipv6 {match-on-ipv6}?
| | | +--rw dscp? inet:dscp
| | | +--rw ecn? uint8
| | | +--rw length? uint16
| | | +--rw ttl? uint8
| | | +--rw protocol? uint8
| | | +--rw source-port-range!
| | | | +--rw lower-port inet:port-number
| | | | +--rw upper-port? inet:port-number
| | | | +--rw operation? operator
| | | +--rw destination-port-range!
| | | | +--rw lower-port inet:port-number
| | | | +--rw upper-port? inet:port-number
| | | | +--rw operations? operator
| | | +--rw next-header? uint8
| | | +--rw destination-ipv6-network? inet:ipv6-prefix
| | | +--rw source-ipv6-network? inet:ipv6-prefix
| | | +--rw flow-label? inet:ipv6-flow-label
| | +--rw (l4)?
| | | +--:(tcp)
| | | | +--rw tcp {match-on-tcp}?
| | | | +--rw sequence-number? uint32
| | | | +--rw acknowledgement-number? uint32
| | | | +--rw data-offset? uint8
| | | | +--rw reserved? uint8
| | | | +--rw flags? bits
| | | | +--rw window-size? uint16
| | | | +--rw urgent-pointer? uint16
| | | | +--rw options? uint32
| | | +--:(udp)
| | | | +--rw udp {match-on-udp}?
| | | | +--rw length? uint16
| | | +--:(icmp)
| | | +--rw icmp {match-on-icmp}?
| | | +--rw type? uint8
| | | +--rw code? uint8
| | | +--rw rest-of-header? uint32
| +--ro matched-packets? yang:counter64
| +--ro matched-octets? yang:counter64
This document defines the DOTS Data Channel YANG to augment the "ietf-access-control-list" module to support filters based on the DOTS client unique identifier (cuid) and/or the client domain identity (client-domain-hash), to support rate-limit action (rate-limit), and to handle fragmented packets (fragments). The tree structure for augmented DOTS filtering rules is as follows:
augment /ietf-acl:access-lists/ietf-acl:acl:
+--rw cuid string
+--rw client-domain-hash? string
+--rw lifetime int32
augment /ietf-acl:access-lists/ietf-acl:acl/ietf-acl:aces
/ietf-acl:ace/ietf-acl:actions:
+--rw rate-limit? decimal64
augment /ietf-acl:access-lists/ietf-acl:acl/ietf-acl:aces
/ietf-acl:ace/ietf-acl:matches/ietf-acl:ipv4-acl:
+--rw fragments? empty
augment /ietf-acl:access-lists/ietf-acl:acl/ietf-acl:aces
/ietf-acl:ace/ietf-acl:matches/ietf-acl:ipv6-acl:
+--rw fragments? empty
augment /ietf-acl:access-lists:
+--rw dots-acl-order
+--rw acl-set* [cuid name type]
+--rw cuid -> /ietf-acl:access-lists/acl/cuid
+--rw client-domain-hash? -> /ietf-acl:access-lists/acl/client-domain-hash
+--rw name -> /ietf-acl:access-lists/acl/acl-name
+--rw type -> /ietf-acl:access-lists/acl/acl-type
Filtering fragments adds an additional layer of protection against a DoS attack that uses non-initial fragments only. When there is only Layer 3 information in the ACL entry and the fragments keyword is present, for non-initial fragments matching the ACL entry, the 'deny' or 'permit' action associated with the ACL entry will be enforced. For initial or non-fragment matching the ACL entry, the next ACL entry will be processed. When there is both Layer 3 and Layer 4 information in the ACL entry and the fragments keyword is present, the ACL action is conservative for both permit and deny actions. The actions are conservative to not accidentally deny a fragmented portion of a flow because the fragments do not contain sufficient information to match all of the filter attributes. In the deny action case, instead of denying a non-initial fragment, the next ACL entry is processed. In the permit case, it is assumed that the Layer 4 information in the non-initial fragment, if available, matches the Layer 4 information in the ACL entry.
<CODE BEGINS> file "ietf-dots-data-channel@2018-01-09.yang"
module ietf-dots-data-channel {
yang-version 1.1;
namespace "urn:ietf:params:xml:ns:yang:ietf-dots-data-channel";
prefix "data-channel";
import ietf-inet-types {prefix "inet";}
import ietf-access-control-list {prefix "ietf-acl";}
organization "IETF DDoS Open Threat Signaling (DOTS) Working Group";
contact
"WG Web: <https://datatracker.ietf.org/wg/dots/>
WG List: <mailto:dots@ietf.org>
Editor: Konda, Tirumaleswar Reddy
<mailto:TirumaleswarReddy_Konda@McAfee.com>
Editor: Mohamed Boucadair
<mailto:mohamed.boucadair@orange.com>
Author: Kaname Nishizuka
<mailto:kaname@nttv6.jp>
Author: Liang Xia
<mailto:frank.xialiang@huawei.com>
Author: Prashanth Patil
<mailto:praspati@cisco.com>
Author: Andrew Mortensen
<mailto:amortensen@arbor.net>
Author: Nik Teague
<mailto:nteague@verisign.com>";
description
"This module contains YANG definition for configuring
aliases for resources and filtering rules using DOTS
data channel.
Copyright (c) 2017 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 2018-01-09 {
description
"Initial revision.";
reference
"RFC XXXX: Distributed Denial-of-Service Open Threat
Signaling (DOTS) Data Channel";
}
container aliases {
description "Top level container for aliases";
list dots-client {
key cuid;
description
"List of DOTS clients";
leaf cuid {
type string;
description
"A unique identifier that is randomly
generated by a DOTS client to prevent
request collisions.";
reference
"I-D.itef-dots-signal-channel: Distributed Denial-of-Service
Open Threat Signaling (DOTS) Signal Channel";
}
leaf client-domain-hash {
type string;
description
"A client domain identifier conveyed by a
server-domain DOTS gateway to a remote DOTS server.";
reference
"I-D.itef-dots-signal-channel: Distributed Denial-of-Service
Open Threat Signaling (DOTS) Signal Channel";
}
list alias {
key alias-name;
description
"List of aliases";
leaf alias-name {
type string;
description "alias name";
}
leaf-list target-prefix {
type inet:ip-prefix;
description
"IPv4 or IPv6 prefix identifying the target.";
}
list target-port-range {
key "lower-port upper-port";
description
"Port range. When only lower-port is
present, it represents a single port.";
leaf lower-port {
type inet:port-number;
mandatory true;
description
"Lower port number.";
}
leaf upper-port {
type inet:port-number;
must ". >= ../lower-port" {
error-message
"The upper port number must be greater than
or equal to the lower port number.";
}
description
"Upper port number.";
}
}
leaf-list target-protocol {
type uint8;
description
"Identifies the target protocol number.
The value '0' means 'all protocols'.
Values are taken from the IANA protocol registry:
https://www.iana.org/assignments/protocol-numbers/
protocol-numbers.xhtml
For example, 6 for a TCP or 17 for UDP.";
}
leaf-list target-fqdn {
type inet:domain-name;
description
"FQDN identifying the target.";
}
leaf-list target-uri {
type inet:uri;
description
"URI identifying the target.";
}
}
}
}
/*augment "/ietf-acl:access-lists" {
description
"Augment ACLs with the identity of the DOTS
client and client's domain hash.";
leaf cuid {
type string;
description
"A unique identifier that is randomly
generated by a DOTS client to prevent
request collisions.";
reference
"I-D.itef-dots-signal-channel: Distributed Denial-of-Service
Open Threat Signaling (DOTS) Signal Channel";
}
leaf client-domain-hash {
type string;
description
"A client identifier conveyed by a server-domain DOTS
gateway to a remote DOTS server.";
}
} */
augment "/ietf-acl:access-lists/ietf-acl:acl" {
when "derived-from(ietf-acl:acl-type, 'ietf-acl:ipv4-acl')" +
" or derived-from(ietf-acl:acl-type, 'ietf-acl:ipv6-acl')";
description
"Augments ACLs with the identity of the DOTS
client, the client's domain hash, and the lifetime.";
leaf cuid {
type string;
mandatory true;
description
"A unique identifier that is randomly
generated by a DOTS client to prevent
request collisions.";
reference
"I-D.itef-dots-signal-channel: Distributed Denial-of-Service
Open Threat Signaling (DOTS) Signal Channel";
}
leaf client-domain-hash {
type string;
description
"A client identifier conveyed by a server-domain DOTS
gateway to a remote DOTS server.";
}
leaf lifetime {
type int32;
units "minutes";
mandatory true;
description
"Indicates the lifetime of the filtering rule
A lifetime of negative one (-1) indicates indefinite
lifetime for the filtering request.";
}
}
augment "/ietf-acl:access-lists/ietf-acl:acl/ietf-acl:aces" +
"/ietf-acl:ace/ietf-acl:actions" {
description
"rate-limit action";
leaf rate-limit {
when "/ietf-acl:access-lists/ietf-acl:acl/ietf-acl:aces/" +
"ietf-acl:ace/ietf-acl:actions/" +
"ietf-acl:forwarding = 'ietf-acl:accept'" {
description
"rate-limit valid only when accept action is used";
}
type decimal64 {
fraction-digits 2;
}
description
"rate-limit traffic";
}
}
augment "/ietf-acl:access-lists/ietf-acl:acl/ietf-acl:aces" +
"/ietf-acl:ace/ietf-acl:matches/ietf-acl:ipv4-acl" {
description
"Handle non-initial and initial fragments for IPv4 packets.";
leaf fragments {
type empty;
description
"Handle fragments.";
}
}
augment "/ietf-acl:access-lists/ietf-acl:acl/ietf-acl:aces" +
"/ietf-acl:ace/ietf-acl:matches/ietf-acl:ipv6-acl" {
description
"Handle non-initial and initial fragments for IPv6 packets.";
leaf fragments {
type empty;
description
"Handle fragments.";
}
}
augment "/ietf-acl:access-lists" {
description
"Handle ordering of ACLs from a DOTS client";
container dots-acl-order {
description
"Enclosing container for ordering
the ACLs from a DOTS client";
list acl-set {
key "cuid name type";
ordered-by user;
description
"List of ACLs";
leaf cuid {
type leafref {
path "/ietf-acl:access-lists/ietf-acl:acl" +
"/cuid";
}
description
"Reference to the CUID";
}
leaf client-domain-hash {
type leafref {
path "/ietf-acl:access-lists/ietf-acl:acl" +
"/client-domain-hash";
}
description
"Reference to the client domain hash.";
}
leaf name {
type leafref {
path "/ietf-acl:access-lists/ietf-acl:acl" +
"/ietf-acl:acl-name";
}
description
"Reference to the ACL set name";
}
leaf type {
type leafref {
path "/ietf-acl:access-lists/ietf-acl:acl" +
"/ietf-acl:acl-type";
}
description
"Reference to the ACL set type";
}
}
}
}
}
<CODE ENDS>
A POST request is used to create aliases, for resources for which a mitigation may be requested. Such aliases may be used in subsequent DOTS signal channel exchanges to refer more efficiently to the resources under attack (Figure 3).
DOTS clients within the same domain can create different aliases for the same resource.
POST /restconf/data/ietf-dots-data-channel:aliases HTTP/1.1
Host: {host}:{port}
Content-Type: application/yang-data+json
{
"ietf-dots-data-channel:dots-client": {
"cuid": string,
"alias": [
{
"alias-name": "string",
"target-prefix": [
"string"
],
"target-port-range": [
{
"lower-port": integer,
"upper-port": integer
}
],
"target-protocol": [
integer
],
"target-fqdn": [
"string"
],
"target-uri": [
"string"
]
}
]
}
}
Figure 3: POST to Create Aliases
The parameters are described below:
POST /restconf/data/ietf-dots-data-channel HTTP/1.1
Host: {host}:{port}
Content-Type: application/yang-data+json
{
"ietf-dots-data-channel:dots-client": {
"client-domain-hash": "string",
"cuid": "string",
"alias": [
{
"alias-name": "string",
"target-prefix": [
"string"
],
"target-port-range": [
{
"lower-port": integer,
"upper-port": integer
}
],
"target-protocol": [
integer
],
"target-fqdn": [
"string"
],
"target-uri": [
"string"
]
}
]
}
}
Figure 4: POST to Create Aliases (DOTS Gateway)
In deployments where server-domain DOTS gateways are enabled, identity information about the origin source client domain has to be supplied to the DOTS server. That information is meant to assist the DOTS server to enforce some policies. Figure 4 shows an example of a request relayed by a server-domain DOTS gateway.
In the POST request, at least one of the 'target-prefix' or 'target-fqdn' or 'target-uri' attributes MUST be present. DOTS agents can safely ignore Vendor-Specific parameters they don't understand.
Figure 5 shows a POST request to create alias called "https1" for HTTPS servers with IP addresses 2001:db8:6401::1 and 2001:db8:6401::2 listening on port number 443.
POST /restconf/data/ietf-dots-data-channel HTTP/1.1
Host: www.example.com
Content-Type: application/yang-data+json
{
"ietf-dots-data-channel:dots-client": {
"cuid": "7dec-11d0-a765-00a0c91e6bf6@foo.bar.example",
"alias": [
{
"alias-name": "https1",
"target-protocol": [
6
],
"target-prefix": [
"2001:db8:6401::1/128",
"2001:db8:6401::2/128"
],
"target-port-range": [
{
"lower-port": 443
}
]
}
]
}
}
Figure 5: Example of a POST to Create Aliases
The DOTS server indicates the result of processing the POST request using status-line codes. Status codes in the range "2xx" codes are success, "4xx" codes are some sort of invalid requests and "5xx" codes are returned if the DOTS server has erred or is incapable of accepting the alias.
"201 Created" status-line is returned in the response if the DOTS server has accepted the alias.
If the request is missing one or more mandatory attributes, or if the request contains invalid or unknown parameters, then "400 Bad Request" status-line MUST be returned in the response. The HTTP response will include the JSON body received in the request.
A DOTS client MAY use the PUT request (Section 4.5 in [RFC8040]) to create or modify the aliases in the DOTS server.
A GET request is used to retrieve one or all installed aliases by a DOTS client from a DOTS server (Section 3.3.1 in [RFC8040]). If no 'alias-name' parameter is included in the request, this is an indication that the request is about retrieving all identifiers instantiated by the DOTS client.
Figure 6 shows an example to retrieve all the identifiers that were instantiated by the DOTS client. The content parameter and its permitted values are defined in Section 4.8.1 of [RFC8040].
GET /restconf/data/ietf-dots-data-channel:aliases\
/cuid=7dec-11d0-a765-00a0c91e6bf6@foo.bar.example?content=config HTTP/1.1
Host: {host}:{port}
Accept: application/yang-data+json
Figure 6: GET to Retrieve All Installed Aliases
Figure 7 shows an example of response message body that includes all the aliases that are maintained by the DOTS server for the DOTS client identified by the 'cuid' parameter.
{
"ietf-dots-data-channel:dots-client": {
"cuid": "7dec-11d0-a765-00a0c91e6bf6@foo.bar.example",
"alias": [
{
"alias-name": "Server1",
"traffic-protocol": [
6
],
"target-prefix": [
"2001:db8:6401::1/128",
"2001:db8:6401::2/128"
],
"target-port-range": [
{
"lower-port": 443
}
]
},
{
"alias-name": "Server2",
"target-protocol": [
6
],
"target-prefix": [
"2001:db8:6401::10/128",
"2001:db8:6401::20/128"
],
"target-port-range": [
{
"lower-port": 80
}
]
}
]
}
}
Figure 7: An Example of Response Body
If the 'alias-name' parameter is included in the request, but the DOTS server does not find that alias name in its configuration data, it MUST respond with a "404 Not Found" status-line.
A DELETE request is used to delete aliases maintained by a DOTS server.
In RESTCONF, URI-encoded path expressions are used. A RESTCONF data resource identifier is encoded from left to right, starting with the top-level data node, according to the 'api-path' rule defined in Section 3.5.3.1 of [RFC8040]. The data node in the path expression is a YANG list node and MUST be encoded according to the rules defined in Section 3.5.1 of [RFC8040].
If the DOTS server does not find the alias name conveyed in the DELETE request in its configuration data, it MUST respond with a "404 Not Found" status-line.
The DOTS server successfully acknowledges a DOTS client's request to remove the alias using "204 No Content" status-line in the response.
Figure 8 shows an example of a request to delete an alias.
DELETE /restconf/data/ietf-dots-data-channel:aliases\
/cuid=7dec-11d0-a765-00a0c91e6bf6@foo.bar.example/alias-name=Server1 HTTP/1.1
Host: {host}:{port}
Figure 8: Delete an Alias
The DOTS server either receives the filtering rules directly from the DOTS client or via a DOTS gateway.
If the DOTS client signals the filtering rules via a DOTS gateway, the DOTS gateway first verifies that the DOTS client is authorized to signal the filtering rules. If the client is authorized, it propagates the rules to the DOTS server. Likewise, the DOTS server verifies that the DOTS gateway is authorized to signal the filtering rules. To create or purge filters, the DOTS client sends HTTP requests to its DOTS gateway. The DOTS gateway validates the rules in the requests and proxies the requests containing the filtering rules to a DOTS server. When the DOTS gateway receives the associated HTTP response from the DOTS server, it propagates the response back to the DOTS client.
The following sub-sections define means for a DOTS client to configure filtering rules on a DOTS server.
A POST request is used to push filtering rules to a DOTS server.
Figure 9 shows a POST request example to block traffic from 192.0.2.0/24 and destined to 198.51.100.0/24. The ACL JSON configuration for the filtering rule is generated using the ACL YANG module (Section 4.3 of [I-D.ietf-netmod-acl-model]).
POST /restconf/data/ietf-access-control-list HTTP/1.1
Host: www.example.com
Content-Type: application/yang-data+json
{
"ietf-access-control-list:access-lists": {
"acl": [
{
"acl-name": "sample-ipv4-acl",
"acl-type": "ipv4-acl",
"data-channel:cuid": "7dec-11d0-a765-00a0c91e6bf6@foo.bar.example",
"data-channel:lifetime": 10080,
"aces": {
"ace": [
{
"rule-name": "rule1",
"matches": {
"ipv4-acl": {
"source-ipv4-network": "192.0.2.0/24",
"destination-ipv4-network": "198.51.100.0/24"
}
},
"actions": {
"forwarding": "drop"
}
}
]
}
}
]
}
}
Figure 9: POST to Install Filtering Rules
The meaning of these parameters is as follows:
The DOTS server indicates the result of processing the POST request using the status-line header. "2xx" codes are success, 4xx codes are some sort of invalid requests, and 5xx codes are returned if the DOTS server has erred or is incapable of configuring the filtering rules. Concretely, "201 Created" status-line MUST be returned in the response if the DOTS server has accepted the filtering rules. If the request is missing one or more mandatory attributes or contains invalid or unknown parameters, then "400 Bad Request" status-line MUST be returned in the response.
If the request is conflicting with an existing filtering, the DOTS server returns "409 Conflict" status-line to the requesting DOTS client. The error-tag "invalid-value" is used in this case.
The "insert" query parameter (Section 4.8.5 of [RFC8040]) MAY be used to specify how an Access Control Entry (ACE) is inserted within an ACL and how an ACL is inserted within an ACL set in container dots-acl-order.
The DOTS client MAY use the PUT request to create or modify the filtering rules in the DOTS server.
The DOTS client periodically queries the DOTS server to check the counters for installed filtering rules. A GET request is used to retrieve filtering rules from a DOTS server.
If the DOTS server does not find the access list name and access list type conveyed in the GET request in its configuration data, it responds with a "404 Not Found" status-line.
Figure 10 shows how to retrieve all the filtering rules programmed by the DOTS client and the number of matches for the installed filtering rules.
GET /restconf/data/ietf-access-control-list:access-lists\
/data-channel:cuid=7dec-11d0-a765-00a0c91e6bf6@foo.bar.example?\
content=all HTTP/1.1
Host: {host}:{port}
Accept: application/yang-data+json
Figure 10: GET to Retrieve the Configuration Data and State Data for the Filtering Rules
A DELETE request is used to delete filtering rules from a DOTS server.
If the DOTS server does not find the access list name and access list type carried in the DELETE request in its configuration data, it responds with a "404 Not Found" status-line. The DOTS server successfully acknowledges a DOTS client's request to withdraw the filtering rules using "204 No Content" status-line, and removes the filtering rules accordingly.
Figure 11 shows an example of a request to remove the IPv4 ACL named "sample-ipv4-acl".
DELETE /restconf/data/ietf-access-control-list:access-lists\
/data-channel:cuid=7dec-11d0-a765-00a0c91e6bf6@foo.bar.example\
/acl-name=sample-ipv4-acl\
/acl-type=ipv4-acl HTTP/1.1
Host: {host}:{port}
Figure 11: DELETE to Remove the Filtering Rules
URI: urn:ietf:params:xml:ns:yang:ietf-dots-data-channel
Registrant Contact: The IESG.
XML: N/A; the requested URI is an XML namespace.
name: ietf-dots-data-channel
namespace: urn:ietf:params:xml:ns:yang:ietf-dots-data-channel
prefix: data-channel
reference: RFC XXXX
This document requests IANA to register the following URI in the "IETF XML Registry" [RFC3688]: [RFC7950].
The following individuals have contributed to this document:
Dan Wing
Email: dwing-ietf@fuggles.com
RESTCONF security considerations are discussed in [RFC8040]. In particular, DOTS agents MUST follow the security recommendations in Sections 2 and 12 of [RFC8040] and support the mutual authentication TLS profile discussed in Sections 7.1 and 8 of [I-D.ietf-dots-signal-channel].
Authenticated encryption MUST be used for data confidentiality and message integrity. The interaction between the DOTS agents requires Transport Layer Security (TLS) with a cipher suite offering confidentiality protection and the guidance given in [RFC7525] MUST be followed to avoid attacks on TLS.
An attacker may be able to inject RST packets, bogus application segments, etc., regardless of whether TLS authentication is used. Because the application data is TLS protected, this will not result in the application receiving bogus data, but it will constitute a DoS on the connection. This attack can be countered by using TCP-AO [RFC5925]. If TCP-AO is used, then any bogus packets injected by an attacker will be rejected by the TCP-AO integrity check and therefore will never reach the TLS layer.
In order to prevent leaking internal information outside a client-domain, client-side DOTS gateways SHOULD NOT reveal the identity of internal DOTS clients (e.g., source IP address, client's hostname) unless explicitly configured to do so.
Special care should be taken in order to ensure that the activation of the proposed mechanism will not affect the stability of the network (including connectivity and services delivered over that network).
All data nodes defined in the YANG module which can be created, modified, and deleted (i.e., config true, which is the default) are considered sensitive. Write operations applied to these data nodes without proper protection can negatively affect network operations. Appropriate security measures are recommended to prevent illegitimate users from invoking DOTS data channel primitives. Nevertheless, an attacker who can access a DOTS client is technically capable of launching various attacks, such as:
Thanks to Christian Jacquenet, Roland Dobbins, Roman Danyliw, Ehud Doron, Russ White, Jon Shallow, Gilbert Clark, and Nesredien Suleiman for the discussion and comments.