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Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Outdated reference: A later version (-35) exists of draft-ietf-netconf-keystore-00 == Outdated reference: A later version (-40) exists of draft-ietf-netconf-ssh-client-server-01 == Outdated reference: A later version (-41) exists of draft-ietf-netconf-tls-client-server-01 -- Obsolete informational reference (is this intentional?): RFC 5246 (Obsoleted by RFC 8446) -- Obsolete informational reference (is this intentional?): RFC 6536 (Obsoleted by RFC 8341) Summary: 1 error (**), 0 flaws (~~), 11 warnings (==), 3 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 NETCONF Working Group K. Watsen 3 Internet-Draft Juniper Networks 4 Intended status: Standards Track G. Wu 5 Expires: September 14, 2017 Cisco Networks 6 J. Schoenwaelder 7 Jacobs University Bremen 8 March 13, 2017 10 NETCONF Client and Server Models 11 draft-ietf-netconf-netconf-client-server-02 13 Abstract 15 This document defines two YANG modules, one module to configure a 16 NETCONF client and the other module to configure a NETCONF server. 17 Both modules support both the SSH and TLS transport protocols, and 18 support both standard NETCONF and NETCONF Call Home connections. 20 Editorial Note (To be removed by RFC Editor) 22 This draft contains many placeholder values that need to be replaced 23 with finalized values at the time of publication. This note 24 summarizes all of the substitutions that are needed. No other RFC 25 Editor instructions are specified elsewhere in this document. 27 This document contains references to other drafts in progress, both 28 in the Normative References section, as well as in body text 29 throughout. Please update the following references to reflect their 30 final RFC assignments: 32 o I-D.ietf-netconf-keystore 34 o I-D.ietf-netconf-ssh-client-server 36 o I-D.ietf-netconf-tls-client-server 38 Artwork in this document contains shorthand references to drafts in 39 progress. Please apply the following replacements: 41 o "XXXX" --> the assigned RFC value for this draft 43 o "YYYY" --> the assigned RFC value for I-D.ietf-netconf-ssh-client- 44 server 46 o "ZZZZ" --> the assigned RFC value for I-D.ietf-netconf-tls-client- 47 server 49 Artwork in this document contains placeholder values for the date of 50 publication of this draft. Please apply the following replacement: 52 o "2017-03-13" --> the publication date of this draft 54 The following two Appendix sections are to be removed prior to 55 publication: 57 o Appendix A. Change Log 59 o Appendix B. Open Issues 61 Status of This Memo 63 This Internet-Draft is submitted in full conformance with the 64 provisions of BCP 78 and BCP 79. 66 Internet-Drafts are working documents of the Internet Engineering 67 Task Force (IETF). Note that other groups may also distribute 68 working documents as Internet-Drafts. The list of current Internet- 69 Drafts is at http://datatracker.ietf.org/drafts/current/. 71 Internet-Drafts are draft documents valid for a maximum of six months 72 and may be updated, replaced, or obsoleted by other documents at any 73 time. It is inappropriate to use Internet-Drafts as reference 74 material or to cite them other than as "work in progress." 76 This Internet-Draft will expire on September 14, 2017. 78 Copyright Notice 80 Copyright (c) 2017 IETF Trust and the persons identified as the 81 document authors. All rights reserved. 83 This document is subject to BCP 78 and the IETF Trust's Legal 84 Provisions Relating to IETF Documents 85 (http://trustee.ietf.org/license-info) in effect on the date of 86 publication of this document. Please review these documents 87 carefully, as they describe your rights and restrictions with respect 88 to this document. Code Components extracted from this document must 89 include Simplified BSD License text as described in Section 4.e of 90 the Trust Legal Provisions and are provided without warranty as 91 described in the Simplified BSD License. 93 Table of Contents 95 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3 96 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4 97 1.2. Tree Diagrams . . . . . . . . . . . . . . . . . . . . . . 4 98 2. The NETCONF Client Model . . . . . . . . . . . . . . . . . . 4 99 2.1. Tree Diagram . . . . . . . . . . . . . . . . . . . . . . 5 100 2.2. Example Usage . . . . . . . . . . . . . . . . . . . . . . 8 101 2.3. YANG Model . . . . . . . . . . . . . . . . . . . . . . . 10 102 3. The NETCONF Server Model . . . . . . . . . . . . . . . . . . 19 103 3.1. Tree Diagram . . . . . . . . . . . . . . . . . . . . . . 20 104 3.2. Example Usage . . . . . . . . . . . . . . . . . . . . . . 23 105 3.3. YANG Model . . . . . . . . . . . . . . . . . . . . . . . 26 106 4. Design Considerations . . . . . . . . . . . . . . . . . . . . 37 107 4.1. Support all NETCONF transports . . . . . . . . . . . . . 37 108 4.2. Enable each transport to select which keys to use . . . . 37 109 4.3. Support authenticating NETCONF clients certificates . . . 37 110 4.4. Support mapping authenticated NETCONF client certificates 111 to usernames . . . . . . . . . . . . . . . . . . . . . . 38 112 4.5. Support both listening for connections and call home . . 38 113 4.6. For Call Home connections . . . . . . . . . . . . . . . . 38 114 4.6.1. Support more than one NETCONF client . . . . . . . . 38 115 4.6.2. Support NETCONF clients having more than one endpoint 38 116 4.6.3. Support a reconnection strategy . . . . . . . . . . . 38 117 4.6.4. Support both persistent and periodic connections . . 39 118 4.6.5. Reconnection strategy for periodic connections . . . 39 119 4.6.6. Keep-alives for persistent connections . . . . . . . 39 120 4.6.7. Customizations for periodic connections . . . . . . . 39 121 5. Security Considerations . . . . . . . . . . . . . . . . . . . 39 122 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 41 123 6.1. The IETF XML Registry . . . . . . . . . . . . . . . . . . 41 124 6.2. The YANG Module Names Registry . . . . . . . . . . . . . 41 125 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 41 126 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 42 127 8.1. Normative References . . . . . . . . . . . . . . . . . . 42 128 8.2. Informative References . . . . . . . . . . . . . . . . . 43 129 Appendix A. Change Log . . . . . . . . . . . . . . . . . . . . . 44 130 A.1. server-model-09 to 00 . . . . . . . . . . . . . . . . . . 44 131 A.2. 00 to 01 . . . . . . . . . . . . . . . . . . . . . . . . 44 132 A.3. 01 to 02 . . . . . . . . . . . . . . . . . . . . . . . . 44 133 Appendix B. Open Issues . . . . . . . . . . . . . . . . . . . . 44 134 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 44 136 1. Introduction 138 This document defines two YANG [RFC7950] modules, one module to 139 configure a NETCONF client and the other module to configure a 140 NETCONF server. Both modules support both the SSH and TLS transport 141 protocols, and support both standard NETCONF and NETCONF Call Home 142 connections. 144 NETCONF is defined by [RFC6241]. SSH is defined by [RFC4252], 145 [RFC4253], and [RFC4254]. TLS is defined by [RFC5246]. NETCONF Call 146 Home is defined by [RFC8071]). 148 1.1. Terminology 150 The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 151 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 152 document are to be interpreted as described in RFC 2119 [RFC2119]. 154 1.2. Tree Diagrams 156 A simplified graphical representation of the data models is used in 157 this document. The meaning of the symbols in these diagrams is as 158 follows: 160 o Brackets "[" and "]" enclose list keys. 162 o Braces "{" and "}" enclose feature names, and indicate that the 163 named feature must be present for the subtree to be present. 165 o Abbreviations before data node names: "rw" means configuration 166 (read-write) and "ro" state data (read-only). 168 o Symbols after data node names: "?" means an optional node, "!" 169 means a presence container, and "*" denotes a list and leaf-list. 171 o Parentheses enclose choice and case nodes, and case nodes are also 172 marked with a colon (":"). 174 o Ellipsis ("...") stands for contents of subtrees that are not 175 shown. 177 2. The NETCONF Client Model 179 The NETCONF client model presented in this section supports both 180 clients initiating connections to servers, as well as clients 181 listening for connections from servers calling home. 183 This model supports both the SSH and TLS transport protocols, using 184 the SSH client and TLS client groupings defined in 185 [I-D.ietf-netconf-ssh-client-server] and 186 [I-D.ietf-netconf-tls-client-server] respectively. 188 All private keys and trusted certificates are held in the keystore 189 model defined in [I-D.ietf-netconf-keystore]. 191 YANG feature statements are used to enable implementations to 192 advertise which parts of the model the NETCONF client supports. 194 2.1. Tree Diagram 196 Note: all lines are folded at column 71 with no '\' character. 198 module: ietf-netconf-client 199 +--rw netconf-client 200 +--rw initiate {initiate}? 201 | +--rw netconf-server* [name] 202 | +--rw name string 203 | +--rw (transport) 204 | | +--:(ssh) {ssh-initiate}? 205 | | | +--rw ssh 206 | | | +--rw endpoints 207 | | | | +--rw endpoint* [name] 208 | | | | +--rw name string 209 | | | | +--rw address inet:host 210 | | | | +--rw port? inet:port-number 211 | | | +--rw server-auth 212 | | | | +--rw trusted-ssh-host-keys? 213 | | | | | -> /ks:keystore/trusted-host-keys/name 214 | | | | +--rw trusted-ca-certs? leafref 215 | | | | | {sshcom:ssh-x509-certs}? 216 | | | | +--rw trusted-server-certs? leafref 217 | | | | {sshcom:ssh-x509-certs}? 218 | | | +--rw client-auth 219 | | | | +--rw username? string 220 | | | | +--rw (auth-type)? 221 | | | | +--:(certificate) 222 | | | | | +--rw certificate? leafref 223 | | | | | {sshcom:ssh-x509-certs}? 224 | | | | +--:(public-key) 225 | | | | | +--rw public-key? 226 | | | | | -> /ks:keystore/keys/key/name 227 | | | | +--:(password) 228 | | | | +--rw password? union 229 | | | +--rw transport-params 230 | | | {ssh-client-transport-params-config}? 231 | | | +--rw host-key 232 | | | | +--rw host-key-alg* identityref 233 | | | +--rw key-exchange 234 | | | | +--rw key-exchange-alg* identityref 235 | | | +--rw encryption 236 | | | | +--rw encryption-alg* identityref 237 | | | +--rw mac 238 | | | | +--rw mac-alg* identityref 239 | | | +--rw compression 240 | | | +--rw compression-alg* identityref 241 | | +--:(tls) {tls-initiate}? 242 | | +--rw tls 243 | | +--rw endpoints 244 | | | +--rw endpoint* [name] 245 | | | +--rw name string 246 | | | +--rw address inet:host 247 | | | +--rw port? inet:port-number 248 | | +--rw server-auth 249 | | | +--rw trusted-ca-certs? leafref 250 | | | +--rw trusted-server-certs? leafref 251 | | +--rw client-auth 252 | | | +--rw (auth-type)? 253 | | | +--:(certificate) 254 | | | +--rw certificate? leafref 255 | | +--rw hello-params 256 | | {tls-client-hello-params-config}? 257 | | +--rw tls-versions 258 | | | +--rw tls-version* identityref 259 | | +--rw cipher-suites 260 | | +--rw cipher-suite* identityref 261 | +--rw connection-type 262 | | +--rw (connection-type)? 263 | | +--:(persistent-connection) 264 | | | +--rw persistent! 265 | | | +--rw idle-timeout? uint32 266 | | | +--rw keep-alives 267 | | | +--rw max-wait? uint16 268 | | | +--rw max-attempts? uint8 269 | | +--:(periodic-connection) 270 | | +--rw periodic! 271 | | +--rw idle-timeout? uint16 272 | | +--rw reconnect-timeout? uint16 273 | +--rw reconnect-strategy 274 | +--rw start-with? enumeration 275 | +--rw max-attempts? uint8 276 +--rw listen {listen}? 277 +--rw max-sessions? uint16 278 +--rw idle-timeout? uint16 279 +--rw endpoint* [name] 280 +--rw name string 281 +--rw (transport) 282 +--:(ssh) {ssh-listen}? 283 | +--rw ssh 284 | +--rw address? inet:ip-address 285 | +--rw port? inet:port-number 286 | +--rw server-auth 287 | | +--rw trusted-ssh-host-keys? 288 | | | -> /ks:keystore/trusted-host-keys/name 289 | | +--rw trusted-ca-certs? leafref 290 | | | {sshcom:ssh-x509-certs}? 291 | | +--rw trusted-server-certs? leafref 292 | | {sshcom:ssh-x509-certs}? 293 | +--rw client-auth 294 | | +--rw username? string 295 | | +--rw (auth-type)? 296 | | +--:(certificate) 297 | | | +--rw certificate? leafref 298 | | | {sshcom:ssh-x509-certs}? 299 | | +--:(public-key) 300 | | | +--rw public-key? 301 | | | -> /ks:keystore/keys/key/name 302 | | +--:(password) 303 | | +--rw password? union 304 | +--rw transport-params 305 | {ssh-client-transport-params-config}? 306 | +--rw host-key 307 | | +--rw host-key-alg* identityref 308 | +--rw key-exchange 309 | | +--rw key-exchange-alg* identityref 310 | +--rw encryption 311 | | +--rw encryption-alg* identityref 312 | +--rw mac 313 | | +--rw mac-alg* identityref 314 | +--rw compression 315 | +--rw compression-alg* identityref 316 +--:(tls) {tls-listen}? 317 +--rw tls 318 +--rw address? inet:ip-address 319 +--rw port? inet:port-number 320 +--rw server-auth 321 | +--rw trusted-ca-certs? leafref 322 | +--rw trusted-server-certs? leafref 323 +--rw client-auth 324 | +--rw (auth-type)? 325 | +--:(certificate) 326 | +--rw certificate? leafref 327 +--rw hello-params 328 {tls-client-hello-params-config}? 329 +--rw tls-versions 330 | +--rw tls-version* identityref 331 +--rw cipher-suites 332 +--rw cipher-suite* identityref 334 2.2. Example Usage 336 The following example illustrates configuring a NETCONF client to 337 initiate connections, using both the SSH and TLS transport protocols, 338 as well as listening for call-home connections, again using both the 339 SSH and TLS transport protocols. 341 This example is consistent with the examples presented in Section 2.2 342 of [I-D.ietf-netconf-keystore]. 344 347 348 349 350 corp-fw1 351 352 353 354 corp-fw1.example.com 355
corp-fw1.example.com
356 357 358 corp-fw2.example.com 359
corp-fw2.example.com
360 361 362 363 deployment-specific-ca-certs 364 365 366 foobar 367 ex-rsa-key 368 369 370 371 373 374 375 376 Intranet-facing listener 377 378
11.22.33.44
379 380 deployment-specific-ca-certs 381 explicitly-trusted-server-certs 382 explicitly-trusted-ssh-host-keys 383 384 385 foobar 386 ex-rsa-key 387 388 389 390 391 392 2.3. YANG Model 394 This YANG module imports YANG types from [RFC6991] and [RFC7407]. 396 file "ietf-netconf-client@2017-03-13.yang" 398 module ietf-netconf-client { 399 yang-version 1.1; 401 namespace "urn:ietf:params:xml:ns:yang:ietf-netconf-client"; 402 prefix "ncc"; 404 import ietf-inet-types { 405 prefix inet; 406 reference 407 "RFC 6991: Common YANG Data Types"; 408 } 410 import ietf-ssh-client { 411 prefix ss; 412 revision-date 2017-03-13; // stable grouping definitions 413 reference 414 "RFC YYYY: SSH Client and Server Models"; 415 } 417 import ietf-tls-client { 418 prefix ts; 419 revision-date 2017-03-13; // stable grouping definitions 420 reference 421 "RFC ZZZZ: TLS Client and Server Models"; 422 } 424 organization 425 "IETF NETCONF (Network Configuration) Working Group"; 427 contact 428 "WG Web: 429 WG List: 431 Author: Kent Watsen 432 434 Author: Gary Wu 435 "; 437 description 438 "This module contains a collection of YANG definitions for 439 configuring NETCONF clients. 441 Copyright (c) 2014 IETF Trust and the persons identified as 442 authors of the code. All rights reserved. 444 Redistribution and use in source and binary forms, with or 445 without modification, is permitted pursuant to, and subject 446 to the license terms contained in, the Simplified BSD 447 License set forth in Section 4.c of the IETF Trust's 448 Legal Provisions Relating to IETF Documents 449 (http://trustee.ietf.org/license-info). 451 This version of this YANG module is part of RFC XXXX; see 452 the RFC itself for full legal notices."; 454 revision "2017-03-13" { 455 description 456 "Initial version"; 457 reference 458 "RFC XXXX: NETCONF Client and Server Models"; 459 } 461 // Features 463 feature initiate { 464 description 465 "The 'initiate' feature indicates that the NETCONF client 466 supports initiating NETCONF connections to NETCONF servers 467 using at least one transport (e.g., SSH, TLS, etc.)."; 468 } 470 feature ssh-initiate { 471 description 472 "The 'ssh-initiate' feature indicates that the NETCONF client 473 supports initiating SSH connections to NETCONF servers."; 474 reference 475 "RFC 6242: Using the NETCONF Protocol over Secure Shell (SSH)"; 476 } 478 feature tls-initiate { 479 description 480 "The 'tls-initiate' feature indicates that the NETCONF client 481 supports initiating TLS connections to NETCONF servers."; 482 reference 483 "RFC 7589: Using the NETCONF Protocol over Transport 484 Layer Security (TLS) with Mutual X.509 485 Authentication"; 487 } 489 feature listen { 490 description 491 "The 'listen' feature indicates that the NETCONF client 492 supports opening a port to accept NETCONF server call 493 home connections using at least one transport (e.g., 494 SSH, TLS, etc.)."; 495 } 497 feature ssh-listen { 498 description 499 "The 'ssh-listen' feature indicates that the NETCONF client 500 supports opening a port to listen for incoming NETCONF 501 server call-home SSH connections."; 502 reference 503 "RFC 8071: NETCONF Call Home and RESTCONF Call Home"; 504 } 506 feature tls-listen { 507 description 508 "The 'tls-listen' feature indicates that the NETCONF client 509 supports opening a port to listen for incoming NETCONF 510 server call-home TLS connections."; 511 reference 512 "RFC 8071: NETCONF Call Home and RESTCONF Call Home"; 513 } 515 container netconf-client { 516 description 517 "Top-level container for NETCONF client configuration."; 519 container initiate { 520 if-feature initiate; 521 description 522 "Configures client initiating underlying TCP connections."; 523 list netconf-server { 524 key name; 525 description 526 "List of NETCONF servers the NETCONF client is to initiate 527 connections to."; 528 leaf name { 529 type string; 530 description 531 "An arbitrary name for the NETCONF server."; 532 } 533 choice transport { 534 mandatory true; 535 description 536 "Selects between available transports."; 538 case ssh { 539 if-feature ssh-initiate; 540 container ssh { 541 description 542 "Specifies SSH-specific transport configuration."; 543 uses endpoints-container { 544 refine endpoints/endpoint/port { 545 default 830; 546 } 547 } 548 uses ss:ssh-client-grouping; 549 } 550 } // end ssh 552 case tls { 553 if-feature tls-initiate; 554 container tls { 555 description 556 "Specifies TLS-specific transport configuration."; 557 uses endpoints-container { 558 refine endpoints/endpoint/port { 559 default 6513; 560 } 561 } 562 uses ts:tls-client-grouping; 563 } 564 } // end tls 566 } // end transport 568 container connection-type { 569 description 570 "Indicates the kind of connection to use."; 571 choice connection-type { 572 description 573 "Selects between available connection types."; 574 case persistent-connection { 575 container persistent { 576 presence true; 577 description 578 "Maintain a persistent connection to the NETCONF 579 server. If the connection goes down, immediately 580 start trying to reconnect to it, using the 581 reconnection strategy. 583 This connection type minimizes any NETCONF server 584 to NETCONF client data-transfer delay, albeit at 585 the expense of holding resources longer."; 586 leaf idle-timeout { 587 type uint32; 588 units "seconds"; 589 default 86400; // one day; 590 description 591 "Specifies the maximum number of seconds that a 592 a NETCONF session may remain idle. A NETCONF 593 session will be dropped if it is idle for an 594 interval longer than this number of seconds. 595 If set to zero, then the client will never drop 596 a session because it is idle. Sessions that 597 have a notification subscription active are 598 never dropped."; 599 } 600 container keep-alives { 601 description 602 "Configures the keep-alive policy, to proactively 603 test the aliveness of the SSH/TLS server. An 604 unresponsive SSH/TLS server will be dropped after 605 approximately max-attempts * max-wait seconds."; 606 reference 607 "RFC 8071: NETCONF Call Home and RESTCONF Call 608 Home, Section 3.1, item S6"; 609 leaf max-wait { 610 type uint16 { 611 range "1..max"; 612 } 613 units seconds; 614 default 30; 615 description 616 "Sets the amount of time in seconds after which 617 if no data has been received from the SSH/TLS 618 server, a SSH/TLS-level message will be sent 619 to test the aliveness of the SSH/TLS server."; 620 } 621 leaf max-attempts { 622 type uint8; 623 default 3; 624 description 625 "Sets the maximum number of sequential keep-alive 626 messages that can fail to obtain a response from 627 the SSH/TLS server before assuming the SSH/TLS 628 server is no longer alive."; 629 } 630 } 632 } 633 } 634 case periodic-connection { 635 container periodic { 636 presence true; 637 description 638 "Periodically connect to the NETCONF server, so that 639 the NETCONF server may deliver messages pending for 640 the NETCONF client. The NETCONF server must close 641 the connection when it is ready to release it. Once 642 the connection has been closed, the NETCONF client 643 will restart its timer until the next connection."; 644 leaf idle-timeout { 645 type uint16; 646 units "seconds"; 647 default 300; // five minutes 648 description 649 "Specifies the maximum number of seconds that a 650 a NETCONF session may remain idle. A NETCONF 651 session will be dropped if it is idle for an 652 interval longer than this number of seconds. 653 If set to zero, then the server will never drop 654 a session because it is idle. Sessions that 655 have a notification subscription active are 656 never dropped."; 657 } 658 leaf reconnect-timeout { 659 type uint16 { 660 range "1..max"; 661 } 662 units minutes; 663 default 60; 664 description 665 "Sets the maximum amount of unconnected time the 666 NETCONF client will wait before re-establishing 667 a connection to the NETCONF server. The NETCONF 668 client may initiate a connection before this 669 time if desired (e.g., to set configuration)."; 670 } 671 } 672 } 673 } 674 } 675 container reconnect-strategy { 676 description 677 "The reconnection strategy directs how a NETCONF client 678 reconnects to a NETCONF server, after discovering its 679 connection to the server has dropped, even if due to a 680 reboot. The NETCONF client starts with the specified 681 endpoint and tries to connect to it max-attempts times 682 before trying the next endpoint in the list (round 683 robin)."; 684 leaf start-with { 685 type enumeration { 686 enum first-listed { 687 description 688 "Indicates that reconnections should start with 689 the first endpoint listed."; 690 } 691 enum last-connected { 692 description 693 "Indicates that reconnections should start with 694 the endpoint last connected to. If no previous 695 connection has ever been established, then the 696 first endpoint configured is used. NETCONF 697 clients SHOULD be able to remember the last 698 endpoint connected to across reboots."; 699 } 700 } 701 default first-listed; 702 description 703 "Specifies which of the NETCONF server's endpoints the 704 NETCONF client should start with when trying to connect 705 to the NETCONF server."; 706 } 707 leaf max-attempts { 708 type uint8 { 709 range "1..max"; 710 } 711 default 3; 712 description 713 "Specifies the number times the NETCONF client tries to 714 connect to a specific endpoint before moving on to the 715 next endpoint in the list (round robin)."; 716 } 717 } 718 } // end netconf-server 719 } // end initiate 721 container listen { 722 if-feature listen; 723 description 724 "Configures client accepting call-home TCP connections."; 726 leaf max-sessions { 727 type uint16; 728 default 0; 729 description 730 "Specifies the maximum number of concurrent sessions 731 that can be active at one time. The value 0 indicates 732 that no artificial session limit should be used."; 733 } 735 leaf idle-timeout { 736 type uint16; 737 units "seconds"; 738 default 3600; // one hour 739 description 740 "Specifies the maximum number of seconds that a NETCONF 741 session may remain idle. A NETCONF session will be dropped 742 if it is idle for an interval longer than this number of 743 seconds. If set to zero, then the server will never drop 744 a session because it is idle. Sessions that have a 745 notification subscription active are never dropped."; 746 } 748 list endpoint { 749 key name; 750 description 751 "List of endpoints to listen for NETCONF connections."; 752 leaf name { 753 type string; 754 description 755 "An arbitrary name for the NETCONF listen endpoint."; 756 } 757 choice transport { 758 mandatory true; 759 description 760 "Selects between available transports."; 761 case ssh { 762 if-feature ssh-listen; 763 container ssh { 764 description 765 "SSH-specific listening configuration for inbound 766 connections."; 767 leaf address { 768 type inet:ip-address; 769 description 770 "The IP address to listen for call-home connections."; 771 } 772 leaf port { 773 type inet:port-number; 774 default 4334; 775 description 776 "The port number to listen for call-home connections."; 777 } 778 uses ss:ssh-client-grouping; 779 } 780 } 781 case tls { 782 if-feature tls-listen; 783 container tls { 784 description 785 "TLS-specific listening configuration for inbound 786 connections."; 787 leaf address { 788 type inet:ip-address; 789 description 790 "The IP address to listen for call-home connections."; 791 } 792 leaf port { 793 type inet:port-number; 794 default 4335; 795 description 796 "The port number to listen for call-home connections."; 797 } 798 uses ts:tls-client-grouping; 799 } 800 } 801 } // end transport 802 } // end endpoint 803 } // end listen 805 } // end netconf-client 807 grouping endpoints-container { 808 description 809 "This grouping is used to configure a set of NETCONF servers 810 a NETCONF client may initiate connections to."; 811 container endpoints { 812 description 813 "Container for the list of endpoints."; 814 list endpoint { 815 key name; 816 unique "address port"; 817 min-elements 1; 818 ordered-by user; 819 description 820 "A non-empty user-ordered list of endpoints for this NETCONF 821 client to try to connect to. Defining more than one enables 822 high-availability."; 824 leaf name { 825 type string; 826 description 827 "An arbitrary name for this endpoint."; 828 } 829 leaf address { 830 type inet:host; 831 mandatory true; 832 description 833 "The IP address or hostname of the endpoint. If a 834 hostname is configured and the DNS resolution results 835 in more than one IP address, the NETCONF client 836 will process the IP addresses as if they had been 837 explicitly configured in place of the hostname."; 838 } 839 leaf port { 840 type inet:port-number; 841 description 842 "The IP port for this endpoint. The NETCONF client will 843 use the IANA-assigned well-known port (set via a refine 844 statement when uses) if no value is specified."; 845 } 846 } 847 } 848 } 849 } 851 853 3. The NETCONF Server Model 855 The NETCONF server model presented in this section supports servers 856 both listening for connections as well as initiating call-home 857 connections. 859 This model supports both the SSH and TLS transport protocols, using 860 the SSH server and TLS server groupings defined in 861 [I-D.ietf-netconf-ssh-client-server] and 862 [I-D.ietf-netconf-tls-client-server] respectively. 864 All private keys and trusted certificates are held in the keystore 865 model defined in [I-D.ietf-netconf-keystore]. 867 YANG feature statements are used to enable implementations to 868 advertise which parts of the model the NETCONF server supports. 870 3.1. Tree Diagram 872 Note: all lines are folded at column 71 with no '\' character. 874 module: ietf-netconf-server 875 +--rw netconf-server 876 +--rw session-options 877 | +--rw hello-timeout? uint16 878 +--rw listen {listen}? 879 | +--rw max-sessions? uint16 880 | +--rw idle-timeout? uint16 881 | +--rw endpoint* [name] 882 | +--rw name string 883 | +--rw (transport) 884 | +--:(ssh) {ssh-listen}? 885 | | +--rw ssh 886 | | +--rw address? inet:ip-address 887 | | +--rw port? inet:port-number 888 | | +--rw host-keys 889 | | | +--rw host-key* [name] 890 | | | +--rw name string 891 | | | +--rw (host-key-type) 892 | | | +--:(public-key) 893 | | | | +--rw public-key? 894 | | | | -> /ks:keystore/keys/key/name 895 | | | +--:(certificate) 896 | | | +--rw certificate? leafref 897 | | | {sshcom:ssh-x509-certs}? 898 | | +--rw client-cert-auth {sshcom:ssh-x509-certs}? 899 | | | +--rw trusted-ca-certs? leafref 900 | | | +--rw trusted-client-certs? leafref 901 | | +--rw transport-params 902 | | {ssh-server-transport-params-config}? 903 | | +--rw host-key 904 | | | +--rw host-key-alg* identityref 905 | | +--rw key-exchange 906 | | | +--rw key-exchange-alg* identityref 907 | | +--rw encryption 908 | | | +--rw encryption-alg* identityref 909 | | +--rw mac 910 | | | +--rw mac-alg* identityref 911 | | +--rw compression 912 | | +--rw compression-alg* identityref 913 | +--:(tls) {tls-listen}? 914 | +--rw tls 915 | +--rw address? inet:ip-address 916 | +--rw port? inet:port-number 917 | +--rw certificates 918 | | +--rw certificate* [name] 919 | | +--rw name leafref 920 | +--rw client-auth 921 | | +--rw trusted-ca-certs? leafref 922 | | +--rw trusted-client-certs? leafref 923 | | +--rw cert-maps 924 | | +--rw cert-to-name* [id] 925 | | +--rw id uint32 926 | | +--rw fingerprint x509c2n:tls-fingerprint 927 | | +--rw map-type identityref 928 | | +--rw name string 929 | +--rw hello-params 930 | {tls-server-hello-params-config}? 931 | +--rw tls-versions 932 | | +--rw tls-version* identityref 933 | +--rw cipher-suites 934 | +--rw cipher-suite* identityref 935 +--rw call-home {call-home}? 936 +--rw netconf-client* [name] 937 +--rw name string 938 +--rw (transport) 939 | +--:(ssh) {ssh-call-home}? 940 | | +--rw ssh 941 | | +--rw endpoints 942 | | | +--rw endpoint* [name] 943 | | | +--rw name string 944 | | | +--rw address inet:host 945 | | | +--rw port? inet:port-number 946 | | +--rw host-keys 947 | | | +--rw host-key* [name] 948 | | | +--rw name string 949 | | | +--rw (host-key-type) 950 | | | +--:(public-key) 951 | | | | +--rw public-key? 952 | | | | -> /ks:keystore/keys/key/name 953 | | | +--:(certificate) 954 | | | +--rw certificate? leafref 955 | | | {sshcom:ssh-x509-certs}? 956 | | +--rw client-cert-auth {sshcom:ssh-x509-certs}? 957 | | | +--rw trusted-ca-certs? leafref 958 | | | +--rw trusted-client-certs? leafref 959 | | +--rw transport-params 960 | | {ssh-server-transport-params-config}? 961 | | +--rw host-key 962 | | | +--rw host-key-alg* identityref 963 | | +--rw key-exchange 964 | | | +--rw key-exchange-alg* identityref 965 | | +--rw encryption 966 | | | +--rw encryption-alg* identityref 967 | | +--rw mac 968 | | | +--rw mac-alg* identityref 969 | | +--rw compression 970 | | +--rw compression-alg* identityref 971 | +--:(tls) {tls-call-home}? 972 | +--rw tls 973 | +--rw endpoints 974 | | +--rw endpoint* [name] 975 | | +--rw name string 976 | | +--rw address inet:host 977 | | +--rw port? inet:port-number 978 | +--rw certificates 979 | | +--rw certificate* [name] 980 | | +--rw name leafref 981 | +--rw client-auth 982 | | +--rw trusted-ca-certs? leafref 983 | | +--rw trusted-client-certs? leafref 984 | | +--rw cert-maps 985 | | +--rw cert-to-name* [id] 986 | | +--rw id uint32 987 | | +--rw fingerprint x509c2n:tls-fingerprint 988 | | +--rw map-type identityref 989 | | +--rw name string 990 | +--rw hello-params 991 | {tls-server-hello-params-config}? 992 | +--rw tls-versions 993 | | +--rw tls-version* identityref 994 | +--rw cipher-suites 995 | +--rw cipher-suite* identityref 996 +--rw connection-type 997 | +--rw (connection-type)? 998 | +--:(persistent-connection) 999 | | +--rw persistent! 1000 | | +--rw idle-timeout? uint32 1001 | | +--rw keep-alives 1002 | | +--rw max-wait? uint16 1003 | | +--rw max-attempts? uint8 1004 | +--:(periodic-connection) 1005 | +--rw periodic! 1006 | +--rw idle-timeout? uint16 1007 | +--rw reconnect-timeout? uint16 1008 +--rw reconnect-strategy 1009 +--rw start-with? enumeration 1010 +--rw max-attempts? uint8 1012 3.2. Example Usage 1014 The following example illustrates configuring a NETCONF server to 1015 listen for NETCONF client connections using both the SSH and TLS 1016 transport protocols, as well as configuring call-home to two NETCONF 1017 clients, one using SSH and the other using TLS. 1019 This example is consistent with the examples presented in Section 2.2 1020 of [I-D.ietf-netconf-keystore]. 1022 1026 1027 1028 1029 netconf/ssh 1030 1031
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1032 1033 1034 public-key 1035 ex-rsa-key 1036 1037 1038 certificate 1039 builtin-idevid-cert 1040 1041 1042 1043 deployment-specific-ca-certs 1044 explicitly-trusted-client-certs 1045 1046 1047 1048 1049 netconf/tls 1050 1051
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1052 1053 1054 tls-ec-cert 1055 1056 1057 1058 deployment-specific-ca-certs 1059 explicitly-trusted-client-certs 1060 1061 1062 1 1063 11:0A:05:11:00 1064 x509c2n:san-any 1065 1066 1067 2 1068 B3:4F:A1:8C:54 1069 x509c2n:specified 1070 scooby-doo 1071 1072 1073 1074 1075 1076 1078 1079 1080 1081 config-mgr 1082 1083 1084 1085 east-data-center 1086
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1087 1088 1089 west-data-center 1090
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1091 1092 1093 1094 1095 certificate 1096 builtin-idevid-cert 1097 1098 1099 1100 deployment-specific-ca-certs 1101 explicitly-trusted-client-certs 1102 1103 1104 1105 1106 300 1107 60 1109 1110 1111 1112 last-connected 1113 3 1114 1115 1116 1117 event-correlator 1118 1119 1120 1121 east-data-center 1122
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1123 1124 1125 west-data-center 1126
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1127 1128 1129 1130 1131 tls-ec-cert 1132 1133 1134 1135 deployment-specific-ca-certs 1136 explicitly-trusted-client-certs 1137 1138 1139 1 1140 11:0A:05:11:00 1141 x509c2n:san-any 1142 1143 1144 2 1145 B3:4F:A1:8C:54 1146 x509c2n:specified 1147 scooby-doo 1148 1149 1150 1151 1152 1153 1154 300 1155 1156 30 1157 3 1158 1159 1160 1161 1162 first-listed 1163 3 1164 1165 1166 1167 1169 3.3. YANG Model 1171 This YANG module imports YANG types from [RFC6991] and [RFC7407]. 1173 file "ietf-netconf-server@2017-03-13.yang" 1175 module ietf-netconf-server { 1176 yang-version 1.1; 1178 namespace "urn:ietf:params:xml:ns:yang:ietf-netconf-server"; 1179 prefix "ncs"; 1181 import ietf-inet-types { 1182 prefix inet; 1183 reference 1184 "RFC 6991: Common YANG Data Types"; 1185 } 1187 import ietf-x509-cert-to-name { 1188 prefix x509c2n; 1189 reference 1190 "RFC 7407: A YANG Data Model for SNMP Configuration"; 1191 } 1193 import ietf-ssh-server { 1194 prefix ss; 1195 revision-date 2017-03-13; // stable grouping definitions 1196 reference 1197 "RFC YYYY: SSH Client and Server Models"; 1198 } 1200 import ietf-tls-server { 1201 prefix ts; 1202 revision-date 2017-03-13; // stable grouping definitions 1203 reference 1204 "RFC ZZZZ: TLS Client and Server Models"; 1205 } 1207 organization 1208 "IETF NETCONF (Network Configuration) Working Group"; 1210 contact 1211 "WG Web: 1212 WG List: 1214 Author: Kent Watsen 1215 "; 1217 description 1218 "This module contains a collection of YANG definitions for 1219 configuring NETCONF servers. 1221 Copyright (c) 2014 IETF Trust and the persons identified as 1222 authors of the code. All rights reserved. 1224 Redistribution and use in source and binary forms, with or 1225 without modification, is permitted pursuant to, and subject 1226 to the license terms contained in, the Simplified BSD 1227 License set forth in Section 4.c of the IETF Trust's 1228 Legal Provisions Relating to IETF Documents 1229 (http://trustee.ietf.org/license-info). 1231 This version of this YANG module is part of RFC XXXX; see 1232 the RFC itself for full legal notices."; 1234 revision "2017-03-13" { 1235 description 1236 "Initial version"; 1237 reference 1238 "RFC XXXX: NETCONF Client and Server Models"; 1239 } 1241 // Features 1243 feature listen { 1244 description 1245 "The 'listen' feature indicates that the NETCONF server 1246 supports opening a port to accept NETCONF client connections 1247 using at least one transport (e.g., SSH, TLS, etc.)."; 1248 } 1249 feature ssh-listen { 1250 description 1251 "The 'ssh-listen' feature indicates that the NETCONF server 1252 supports opening a port to accept NETCONF over SSH 1253 client connections."; 1254 reference 1255 "RFC 6242: Using the NETCONF Protocol over Secure Shell (SSH)"; 1256 } 1258 feature tls-listen { 1259 description 1260 "The 'tls-listen' feature indicates that the NETCONF server 1261 supports opening a port to accept NETCONF over TLS 1262 client connections."; 1263 reference 1264 "RFC 7589: Using the NETCONF Protocol over Transport 1265 Layer Security (TLS) with Mutual X.509 1266 Authentication"; 1267 } 1269 feature call-home { 1270 description 1271 "The 'call-home' feature indicates that the NETCONF server 1272 supports initiating NETCONF call home connections to NETCONF 1273 clients using at least one transport (e.g., SSH, TLS, etc.)."; 1274 reference 1275 "RFC 8071: NETCONF Call Home and RESTCONF Call Home"; 1276 } 1278 feature ssh-call-home { 1279 description 1280 "The 'ssh-call-home' feature indicates that the NETCONF 1281 server supports initiating a NETCONF over SSH call 1282 home connection to NETCONF clients."; 1283 reference 1284 "RFC 8071: NETCONF Call Home and RESTCONF Call Home"; 1285 } 1287 feature tls-call-home { 1288 description 1289 "The 'tls-call-home' feature indicates that the NETCONF 1290 server supports initiating a NETCONF over TLS call 1291 home connection to NETCONF clients."; 1292 reference 1293 "RFC 8071: NETCONF Call Home and RESTCONF Call Home"; 1294 } 1296 // top-level container (groupings below) 1297 container netconf-server { 1298 description 1299 "Top-level container for NETCONF server configuration."; 1301 container session-options { // SHOULD WE REMOVE THIS ALTOGETHER? 1302 description 1303 "NETCONF session options, independent of transport 1304 or connection strategy."; 1305 leaf hello-timeout { 1306 type uint16; 1307 units "seconds"; 1308 default 600; 1309 description 1310 "Specifies the maximum number of seconds that a SSH/TLS 1311 connection may wait for a hello message to be received. 1312 A connection will be dropped if no hello message is 1313 received before this number of seconds elapses. If set 1314 to zero, then the server will wait forever for a hello 1315 message."; 1316 } 1317 } 1319 container listen { 1320 if-feature listen; 1321 description 1322 "Configures listen behavior"; 1323 leaf max-sessions { 1324 type uint16; 1325 default 0; 1326 description 1327 "Specifies the maximum number of concurrent sessions 1328 that can be active at one time. The value 0 indicates 1329 that no artificial session limit should be used."; 1330 } 1331 leaf idle-timeout { 1332 type uint16; 1333 units "seconds"; 1334 default 3600; // one hour 1335 description 1336 "Specifies the maximum number of seconds that a NETCONF 1337 session may remain idle. A NETCONF session will be dropped 1338 if it is idle for an interval longer than this number of 1339 seconds. If set to zero, then the server will never drop 1340 a session because it is idle. Sessions that have a 1341 notification subscription active are never dropped."; 1342 } 1343 list endpoint { 1344 key name; 1345 description 1346 "List of endpoints to listen for NETCONF connections."; 1347 leaf name { 1348 type string; 1349 description 1350 "An arbitrary name for the NETCONF listen endpoint."; 1351 } 1353 choice transport { 1354 mandatory true; 1355 description 1356 "Selects between available transports."; 1357 case ssh { 1358 if-feature ssh-listen; 1359 container ssh { 1360 description 1361 "SSH-specific listening configuration for inbound 1362 connections."; 1363 leaf address { 1364 type inet:ip-address; 1365 description 1366 "The IP address of the interface to listen on. The 1367 SSH server will listen on all interfaces if no value 1368 is specified. Please note that some addresses have 1369 special meanings (e.g., '0.0.0.0' and '::')."; 1370 } 1371 leaf port { 1372 type inet:port-number; 1373 default 830; 1374 description 1375 "The local port number on this interface the SSH server 1376 listens on."; 1377 } 1378 uses ss:ssh-server-grouping; 1379 } 1380 } 1381 case tls { 1382 if-feature tls-listen; 1383 container tls { 1384 description 1385 "TLS-specific listening configuration for inbound 1386 connections."; 1387 leaf address { 1388 type inet:ip-address; 1389 description 1390 "The IP address of the interface to listen on. The 1391 TLS server will listen on all interfaces if no value 1392 is specified. Please note that some addresses have 1393 special meanings (e.g., '0.0.0.0' and '::')."; 1394 } 1395 leaf port { 1396 type inet:port-number; 1397 default 6513; 1398 description 1399 "The local port number on this interface the TLS server 1400 listens on."; 1401 } 1402 uses ts:tls-server-grouping { 1403 augment "client-auth" { 1404 description 1405 "Augments in the cert-to-name structure."; 1406 uses cert-maps-grouping; 1407 } 1408 } 1409 } 1410 } 1411 } 1412 } 1413 } 1415 container call-home { 1416 if-feature call-home; 1417 description 1418 "Configures call-home behavior"; 1419 list netconf-client { 1420 key name; 1421 description 1422 "List of NETCONF clients the NETCONF server is to initiate 1423 call-home connections to."; 1424 leaf name { 1425 type string; 1426 description 1427 "An arbitrary name for the remote NETCONF client."; 1428 } 1429 choice transport { 1430 mandatory true; 1431 description 1432 "Selects between available transports."; 1433 case ssh { 1434 if-feature ssh-call-home; 1435 container ssh { 1436 description 1437 "Specifies SSH-specific call-home transport 1438 configuration."; 1439 uses endpoints-container { 1440 refine endpoints/endpoint/port { 1441 default 4334; 1442 } 1443 } 1444 uses ss:ssh-server-grouping; 1445 } 1446 } 1447 case tls { 1448 if-feature tls-call-home; 1449 container tls { 1450 description 1451 "Specifies TLS-specific call-home transport 1452 configuration."; 1453 uses endpoints-container { 1454 refine endpoints/endpoint/port { 1455 default 4335; 1456 } 1457 } 1458 uses ts:tls-server-grouping { 1459 augment "client-auth" { 1460 description 1461 "Augments in the cert-to-name structure."; 1462 uses cert-maps-grouping; 1463 } 1464 } 1465 } 1466 } 1467 } 1468 container connection-type { 1469 description 1470 "Indicates the kind of connection to use."; 1471 choice connection-type { 1472 description 1473 "Selects between available connection types."; 1474 case persistent-connection { 1475 container persistent { 1476 presence true; 1477 description 1478 "Maintain a persistent connection to the NETCONF 1479 client. If the connection goes down, immediately 1480 start trying to reconnect to it, using the 1481 reconnection strategy. 1483 This connection type minimizes any NETCONF client 1484 to NETCONF server data-transfer delay, albeit at 1485 the expense of holding resources longer."; 1486 leaf idle-timeout { 1487 type uint32; 1488 units "seconds"; 1489 default 86400; // one day; 1490 description 1491 "Specifies the maximum number of seconds that a 1492 a NETCONF session may remain idle. A NETCONF 1493 session will be dropped if it is idle for an 1494 interval longer than this number of seconds. 1495 If set to zero, then the server will never drop 1496 a session because it is idle. Sessions that 1497 have a notification subscription active are 1498 never dropped."; 1499 } 1500 container keep-alives { 1501 description 1502 "Configures the keep-alive policy, to proactively 1503 test the aliveness of the SSH/TLS client. An 1504 unresponsive SSH/TLS client will be dropped after 1505 approximately max-attempts * max-wait seconds."; 1506 reference 1507 "RFC 8071: NETCONF Call Home and RESTCONF Call 1508 Home, Section 3.1, item S6"; 1509 leaf max-wait { 1510 type uint16 { 1511 range "1..max"; 1512 } 1513 units seconds; 1514 default 30; 1515 description 1516 "Sets the amount of time in seconds after which 1517 if no data has been received from the SSH/TLS 1518 client, a SSH/TLS-level message will be sent 1519 to test the aliveness of the SSH/TLS client."; 1520 } 1521 leaf max-attempts { 1522 type uint8; 1523 default 3; 1524 description 1525 "Sets the maximum number of sequential keep-alive 1526 messages that can fail to obtain a response from 1527 the SSH/TLS client before assuming the SSH/TLS 1528 client is no longer alive."; 1529 } 1530 } 1531 } 1532 } 1533 case periodic-connection { 1534 container periodic { 1535 presence true; 1536 description 1537 "Periodically connect to the NETCONF client, so that 1538 the NETCONF client may deliver messages pending for 1539 the NETCONF server. The NETCONF client must close 1540 the connection when it is ready to release it. Once 1541 the connection has been closed, the NETCONF server 1542 will restart its timer until the next connection."; 1543 leaf idle-timeout { 1544 type uint16; 1545 units "seconds"; 1546 default 300; // five minutes 1547 description 1548 "Specifies the maximum number of seconds that a 1549 a NETCONF session may remain idle. A NETCONF 1550 session will be dropped if it is idle for an 1551 interval longer than this number of seconds. 1552 If set to zero, then the server will never drop 1553 a session because it is idle. Sessions that 1554 have a notification subscription active are 1555 never dropped."; 1556 } 1557 leaf reconnect-timeout { 1558 type uint16 { 1559 range "1..max"; 1560 } 1561 units minutes; 1562 default 60; 1563 description 1564 "Sets the maximum amount of unconnected time the 1565 NETCONF server will wait before re-establishing 1566 a connection to the NETCONF client. The NETCONF 1567 server may initiate a connection before this 1568 time if desired (e.g., to deliver an event 1569 notification message)."; 1570 } 1571 } 1572 } 1573 } 1574 } 1575 container reconnect-strategy { 1576 description 1577 "The reconnection strategy directs how a NETCONF server 1578 reconnects to a NETCONF client, after discovering its 1579 connection to the client has dropped, even if due to a 1580 reboot. The NETCONF server starts with the specified 1581 endpoint and tries to connect to it max-attempts times 1582 before trying the next endpoint in the list (round 1583 robin)."; 1585 leaf start-with { 1586 type enumeration { 1587 enum first-listed { 1588 description 1589 "Indicates that reconnections should start with 1590 the first endpoint listed."; 1591 } 1592 enum last-connected { 1593 description 1594 "Indicates that reconnections should start with 1595 the endpoint last connected to. If no previous 1596 connection has ever been established, then the 1597 first endpoint configured is used. NETCONF 1598 servers SHOULD be able to remember the last 1599 endpoint connected to across reboots."; 1600 } 1601 } 1602 default first-listed; 1603 description 1604 "Specifies which of the NETCONF client's endpoints the 1605 NETCONF server should start with when trying to connect 1606 to the NETCONF client."; 1607 } 1608 leaf max-attempts { 1609 type uint8 { 1610 range "1..max"; 1611 } 1612 default 3; 1613 description 1614 "Specifies the number times the NETCONF server tries to 1615 connect to a specific endpoint before moving on to the 1616 next endpoint in the list (round robin)."; 1617 } 1618 } 1619 } 1620 } 1621 } 1623 grouping cert-maps-grouping { 1624 description 1625 "A grouping that defines a container around the 1626 cert-to-name structure defined in RFC 7407."; 1627 container cert-maps { 1628 uses x509c2n:cert-to-name; 1629 description 1630 "The cert-maps container is used by a TLS-based NETCONF 1631 server to map the NETCONF client's presented X.509 1632 certificate to a NETCONF username. If no matching and 1633 valid cert-to-name list entry can be found, then the 1634 NETCONF server MUST close the connection, and MUST NOT 1635 accept NETCONF messages over it."; 1636 reference 1637 "RFC WWWW: NETCONF over TLS, Section 7"; 1638 } 1639 } 1641 grouping endpoints-container { 1642 description 1643 "This grouping is used to configure a set of NETCONF clients 1644 a NETCONF server may initiate call-home connections to."; 1645 container endpoints { 1646 description 1647 "Container for the list of endpoints."; 1648 list endpoint { 1649 key name; 1650 unique "address port"; 1651 min-elements 1; 1652 ordered-by user; 1653 description 1654 "A non-empty user-ordered list of endpoints for this NETCONF 1655 server to try to connect to. Defining more than one enables 1656 high-availability."; 1657 leaf name { 1658 type string; 1659 description 1660 "An arbitrary name for this endpoint."; 1661 } 1662 leaf address { 1663 type inet:host; 1664 mandatory true; 1665 description 1666 "The IP address or hostname of the endpoint. If a 1667 hostname is configured and the DNS resolution results 1668 in more than one IP address, the NETCONF server 1669 will process the IP addresses as if they had been 1670 explicitly configured in place of the hostname."; 1671 } 1672 leaf port { 1673 type inet:port-number; 1674 description 1675 "The IP port for this endpoint. The NETCONF server will 1676 use the IANA-assigned well-known port (set via a refine 1677 statement when uses) if no value is specified."; 1678 } 1680 } 1681 } 1682 } 1684 } 1686 1688 4. Design Considerations 1690 Editorial: this section is a hold over from before, previously called 1691 "Objectives". It was only written two support the "server" (not the 1692 "client"). The question is if it's better to add the missing 1693 "client" parts, or remove this section altogether. 1695 The primary purpose of the YANG modules defined herein is to enable 1696 the configuration of the NETCONF client and servers. This scope 1697 includes the following objectives: 1699 4.1. Support all NETCONF transports 1701 The YANG module should support all current NETCONF transports, namely 1702 NETCONF over SSH [RFC6242], NETCONF over TLS [RFC7589], and to be 1703 extensible to support future transports as necessary. 1705 Because implementations may not support all transports, the modules 1706 should use YANG "feature" statements so that implementations can 1707 accurately advertise which transports are supported. 1709 4.2. Enable each transport to select which keys to use 1711 Servers may have a multiplicity of host-keys or server-certificates 1712 from which subsets may be selected for specific uses. For instance, 1713 a NETCONF server may want to use one set of SSH host-keys when 1714 listening on port 830, and a different set of SSH host-keys when 1715 calling home. The data models provided herein should enable 1716 configuration of which keys to use on a per-use basis. 1718 4.3. Support authenticating NETCONF clients certificates 1720 When a certificate is used to authenticate a NETCONF client, there is 1721 a need to configure the server to know how to authenticate the 1722 certificates. The server should be able to authenticate the client's 1723 certificate either by using path-validation to a configured trust 1724 anchor or by matching the client-certificate to one previously 1725 configured. 1727 4.4. Support mapping authenticated NETCONF client certificates to 1728 usernames 1730 When a client certificate is used for TLS client authentication, the 1731 NETCONF server must be able to derive a username from the 1732 authenticated certificate. Thus the modules defined herein should 1733 enable this mapping to be configured. 1735 4.5. Support both listening for connections and call home 1737 The NETCONF protocols were originally defined as having the server 1738 opening a port to listen for client connections. More recently the 1739 NETCONF working group defined support for call-home ([RFC8071]), 1740 enabling the server to initiate the connection to the client. Thus 1741 the modules defined herein should enable configuration for both 1742 listening for connections and calling home. Because implementations 1743 may not support both listening for connections and calling home, YANG 1744 "feature" statements should be used so that implementation can 1745 accurately advertise the connection types it supports. 1747 4.6. For Call Home connections 1749 The following objectives only pertain to call home connections. 1751 4.6.1. Support more than one NETCONF client 1753 A NETCONF server may be managed by more than one NETCONF client. For 1754 instance, a deployment may have one client for provisioning and 1755 another for fault monitoring. Therefore, when it is desired for a 1756 server to initiate call home connections, it should be able to do so 1757 to more than one client. 1759 4.6.2. Support NETCONF clients having more than one endpoint 1761 A NETCONF client managing a NETCONF server may implement a high- 1762 availability strategy employing a multiplicity of active and/or 1763 passive endpoint. Therefore, when it is desired for a server to 1764 initiate call home connections, it should be able to connect to any 1765 of the client's endpoints. 1767 4.6.3. Support a reconnection strategy 1769 Assuming a NETCONF client has more than one endpoint, then it becomes 1770 necessary to configure how a NETCONF server should reconnect to the 1771 client should it lose its connection to one the client's endpoints. 1772 For instance, the NETCONF server may start with first endpoint 1773 defined in a user-ordered list of endpoints or with the last 1774 endpoints it was connected to. 1776 4.6.4. Support both persistent and periodic connections 1778 NETCONF clients may vary greatly on how frequently they need to 1779 interact with a NETCONF server, how responsive interactions need to 1780 be, and how many simultaneous connections they can support. Some 1781 clients may need a persistent connection to servers to optimize real- 1782 time interactions, while others prefer periodic interactions in order 1783 to minimize resource requirements. Therefore, when it is necessary 1784 for server to initiate connections, it should be configurable if the 1785 connection is persistent or periodic. 1787 4.6.5. Reconnection strategy for periodic connections 1789 The reconnection strategy should apply to both persistent and 1790 periodic connections. How it applies to periodic connections becomes 1791 clear when considering that a periodic "connection" is a logical 1792 connection to a single server. That is, the periods of 1793 unconnectedness are intentional as opposed to due to external 1794 reasons. A periodic "connection" should always reconnect to the same 1795 server until it is no longer able to, at which time the reconnection 1796 strategy guides how to connect to another server. 1798 4.6.6. Keep-alives for persistent connections 1800 If a persistent connection is desired, it is the responsibility of 1801 the connection initiator to actively test the "aliveness" of the 1802 connection. The connection initiator must immediately work to 1803 reestablish a persistent connection as soon as the connection is 1804 lost. How often the connection should be tested is driven by NETCONF 1805 client requirements, and therefore keep-alive settings should be 1806 configurable on a per-client basis. 1808 4.6.7. Customizations for periodic connections 1810 If a periodic connection is desired, it is necessary for the NETCONF 1811 server to know how often it should connect. This frequency 1812 determines the maximum amount of time a NETCONF client may have to 1813 wait to send data to a server. A server may connect to a client 1814 before this interval expires if desired (e.g., to send data to a 1815 client). 1817 5. Security Considerations 1819 A denial of service (DoS) attack MAY occur if the NETCONF server 1820 limits the maximum number of NETCONF sessions it will accept (i.e. 1821 the 'max-sessions' field in the ietf-netconf-server module is not 1822 zero) and either the "hello-timeout" or "idle-timeout" fields in 1823 ietf-netconf-server module have been set to indicate the NETCONF 1824 server should wait forever (i.e. set to zero). 1826 The YANG module defined in this document uses groupings defined in 1827 [I-D.ietf-netconf-ssh-client-server] and 1828 [I-D.ietf-netconf-tls-client-server]. Please see the Security 1829 Considerations section in those documents for concerns related those 1830 groupings. 1832 The YANG module defined in this document is designed to be accessed 1833 via YANG based management protocols, such as NETCONF [RFC6241] and 1834 RESTCONF [RFC8040]. Both of these protocols have mandatory-to- 1835 implement secure transport layers (e.g., SSH, TLS) with mutual 1836 authentication. 1838 The NETCONF access control model (NACM) [RFC6536] provides the means 1839 to restrict access for particular users to a pre-configured subset of 1840 all available protocol operations and content. 1842 There are a number of data nodes defined in this YANG module that are 1843 writable/creatable/deletable (i.e., config true, which is the 1844 default). These data nodes may be considered sensitive or vulnerable 1845 in some network environments. Write operations (e.g., edit-config) 1846 to these data nodes without proper protection can have a negative 1847 effect on network operations. These are the subtrees and data nodes 1848 and their sensitivity/vulnerability: 1850 NONE 1852 Some of the readable data nodes in this YANG module may be considered 1853 sensitive or vulnerable in some network environments. It is thus 1854 important to control read access (e.g., via get, get-config, or 1855 notification) to these data nodes. These are the subtrees and data 1856 nodes and their sensitivity/vulnerability: 1858 NONE 1860 Some of the RPC operations in this YANG module may be considered 1861 sensitive or vulnerable in some network environments. It is thus 1862 important to control access to these operations. These are the 1863 operations and their sensitivity/vulnerability: 1865 NONE 1867 6. IANA Considerations 1869 6.1. The IETF XML Registry 1871 This document registers two URIs in the IETF XML registry [RFC3688]. 1872 Following the format in [RFC3688], the following registrations are 1873 requested: 1875 URI: urn:ietf:params:xml:ns:yang:ietf-netconf-client 1876 Registrant Contact: The NETCONF WG of the IETF. 1877 XML: N/A, the requested URI is an XML namespace. 1879 URI: urn:ietf:params:xml:ns:yang:ietf-netconf-server 1880 Registrant Contact: The NETCONF WG of the IETF. 1881 XML: N/A, the requested URI is an XML namespace. 1883 6.2. The YANG Module Names Registry 1885 This document registers two YANG modules in the YANG Module Names 1886 registry [RFC7950]. Following the format in [RFC7950], the the 1887 following registrations are requested: 1889 name: ietf-netconf-client 1890 namespace: urn:ietf:params:xml:ns:yang:ietf-netconf-client 1891 prefix: ncc 1892 reference: RFC XXXX 1894 name: ietf-netconf-server 1895 namespace: urn:ietf:params:xml:ns:yang:ietf-netconf-server 1896 prefix: ncs 1897 reference: RFC XXXX 1899 7. Acknowledgements 1901 The authors would like to thank for following for lively discussions 1902 on list and in the halls (ordered by last name): Andy Bierman, Martin 1903 Bjorklund, Benoit Claise, Mehmet Ersue, David Lamparter, Alan Luchuk, 1904 Ladislav Lhotka, Radek Krejci, Tom Petch, Phil Shafer, Sean Turner, 1905 and Bert Wijnen. 1907 Juergen Schoenwaelder and was partly funded by Flamingo, a Network of 1908 Excellence project (ICT-318488) supported by the European Commission 1909 under its Seventh Framework Programme. 1911 8. References 1913 8.1. Normative References 1915 [I-D.ietf-netconf-keystore] 1916 Watsen, K. and G. Wu, "Keystore Model", draft-ietf- 1917 netconf-keystore-00 (work in progress), October 2016. 1919 [I-D.ietf-netconf-ssh-client-server] 1920 Watsen, K. and G. Wu, "SSH Client and Server Models", 1921 draft-ietf-netconf-ssh-client-server-01 (work in 1922 progress), November 2016. 1924 [I-D.ietf-netconf-tls-client-server] 1925 Watsen, K., "TLS Client and Server Models", draft-ietf- 1926 netconf-tls-client-server-01 (work in progress), November 1927 2016. 1929 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 1930 Requirement Levels", BCP 14, RFC 2119, 1931 DOI 10.17487/RFC2119, March 1997, 1932 . 1934 [RFC6241] Enns, R., Ed., Bjorklund, M., Ed., Schoenwaelder, J., Ed., 1935 and A. Bierman, Ed., "Network Configuration Protocol 1936 (NETCONF)", RFC 6241, DOI 10.17487/RFC6241, June 2011, 1937 . 1939 [RFC6242] Wasserman, M., "Using the NETCONF Protocol over Secure 1940 Shell (SSH)", RFC 6242, DOI 10.17487/RFC6242, June 2011, 1941 . 1943 [RFC6991] Schoenwaelder, J., Ed., "Common YANG Data Types", 1944 RFC 6991, DOI 10.17487/RFC6991, July 2013, 1945 . 1947 [RFC7407] Bjorklund, M. and J. Schoenwaelder, "A YANG Data Model for 1948 SNMP Configuration", RFC 7407, DOI 10.17487/RFC7407, 1949 December 2014, . 1951 [RFC7589] Badra, M., Luchuk, A., and J. Schoenwaelder, "Using the 1952 NETCONF Protocol over Transport Layer Security (TLS) with 1953 Mutual X.509 Authentication", RFC 7589, 1954 DOI 10.17487/RFC7589, June 2015, 1955 . 1957 [RFC7950] Bjorklund, M., Ed., "The YANG 1.1 Data Modeling Language", 1958 RFC 7950, DOI 10.17487/RFC7950, August 2016, 1959 . 1961 8.2. Informative References 1963 [RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688, 1964 DOI 10.17487/RFC3688, January 2004, 1965 . 1967 [RFC4252] Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH) 1968 Authentication Protocol", RFC 4252, DOI 10.17487/RFC4252, 1969 January 2006, . 1971 [RFC4253] Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH) 1972 Transport Layer Protocol", RFC 4253, DOI 10.17487/RFC4253, 1973 January 2006, . 1975 [RFC4254] Ylonen, T. and C. Lonvick, Ed., "The Secure Shell (SSH) 1976 Connection Protocol", RFC 4254, DOI 10.17487/RFC4254, 1977 January 2006, . 1979 [RFC5246] Dierks, T. and E. Rescorla, "The Transport Layer Security 1980 (TLS) Protocol Version 1.2", RFC 5246, 1981 DOI 10.17487/RFC5246, August 2008, 1982 . 1984 [RFC6536] Bierman, A. and M. Bjorklund, "Network Configuration 1985 Protocol (NETCONF) Access Control Model", RFC 6536, 1986 DOI 10.17487/RFC6536, March 2012, 1987 . 1989 [RFC8040] Bierman, A., Bjorklund, M., and K. Watsen, "RESTCONF 1990 Protocol", RFC 8040, DOI 10.17487/RFC8040, January 2017, 1991 . 1993 [RFC8071] Watsen, K., "NETCONF Call Home and RESTCONF Call Home", 1994 RFC 8071, DOI 10.17487/RFC8071, February 2017, 1995 . 1997 Appendix A. Change Log 1999 A.1. server-model-09 to 00 2001 o This draft was split out from draft-ietf-netconf-server-model-09. 2003 o Added in previously missing ietf-netconf-client module. 2005 o Added in new features 'listen' and 'call-home' so future 2006 transports can be augmented in. 2008 A.2. 00 to 01 2010 o Renamed "keychain" to "keystore". 2012 A.3. 01 to 02 2014 o Added to ietf-netconf-client ability to connected to a cluster of 2015 endpoints, including a reconnection-strategy. 2017 o Added to ietf-netconf-client the ability to configure connection- 2018 type and also keep-alive strategy. 2020 o Updated both modules to accomodate new groupings in the ssh/tls 2021 drafts. 2023 Appendix B. Open Issues 2025 Please see: https://github.com/netconf-wg/netconf-client-server/ 2026 issues. 2028 Authors' Addresses 2030 Kent Watsen 2031 Juniper Networks 2033 EMail: kwatsen@juniper.net 2035 Gary Wu 2036 Cisco Networks 2038 EMail: garywu@cisco.com 2039 Juergen Schoenwaelder 2040 Jacobs University Bremen 2042 EMail: j.schoenwaelder@jacobs-university.de