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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 1 Storage Maintenance (StorM) Working Group Frederick Knight 2 Internet Draft NetApp 3 Intended status: Standards Track M. Chadalapaka 4 Expires: December 2013 Microsoft 5 June 2013 7 Internet Small Computer Systems Interface (iSCSI) SCSI Features 8 Update 9 draft-ietf-storm-iscsi-sam-07.txt 11 Abstract 13 Internet Small Computer Systems Interface (iSCSI) is a SCSI 14 transport protocol that maps the SCSI family of protocols onto 15 TCP/IP. The iSCSI protocol as specified in [draft-ietf-storm- 16 iscsi-cons-xx] (and as previously specified by the combination 17 of RFC 3720 and RFC 5048) is based on the SAM-2 (SCSI 18 Architecture Model - 2) version of the SCSI family of 19 protocols. This document defines enhancements to the iSCSI 20 protocol to support certain additional features of the SCSI 21 protocol that were defined in SAM-3, SAM-4, and SAM-5. 23 This document is a companion document to [draft-ietf-storm- 24 iscsi-cons-xx]. 26 -------------------------------------------------------- 27 RFC EDITORS NOTE: The above references to [draft-ietf-storm- 28 iscsi-cons-xx] should reference the RFC number assigned to 29 that document, and this note should be removed. 30 -------------------------------------------------------- 32 Status of this Memo 34 This Internet-Draft is submitted to IETF in full conformance with 35 the provisions of BCP 78 and BCP 79. 37 Internet-Drafts are working documents of the Internet Engineering 38 Task Force (IETF), its areas, and its working groups. Note that 39 other groups may also distribute working documents as Internet- 40 Drafts. 42 Internet-Drafts are draft documents valid for a maximum of six 43 months and may be updated, replaced, or obsoleted by other 44 documents at any time. It is inappropriate to use Internet- 45 Drafts as reference material or to cite them other than as "work 46 in progress." 48 The list of current Internet-Drafts can be accessed at 49 http://www.ietf.org/1id-abstracts.html. 51 The list of Internet-Draft Shadow Directories can be accessed at 52 http://www.ietf.org/shadow.html. 54 This Internet-Draft will expire December, 2013. 56 Copyright Notice 58 Copyright (c) 2013 IETF Trust and the persons identified as the 59 document authors. All rights reserved. 61 This document is subject to BCP 78 and the IETF Trust's Legal 62 Provisions Relating to IETF Documents 63 (http://trustee.ietf.org/license-info) in effect on the date of 64 publication of this document. Please review these documents 65 carefully, as they describe your rights and restrictions with 66 respect to this document. Code Components extracted from this 67 document must include Simplified BSD License text as described in 68 Section 4.e of the Trust Legal Provisions and are provided 69 without warranty as described in the Simplified BSD License. 71 Table of Contents 73 1. Introduction.................................................... 3 74 2. Definitions, Acronyms, and Document Summary..................... 3 75 2.1 Definitions ............................................. 3 76 2.2 Acronyms ................................................ 3 77 2.3 New Semantics ........................................... 3 78 3. Terminology Mapping............................................. 4 79 4. New Feature Use................................................. 7 80 4.1 Negotiation of New Feature Use................................. 7 81 4.2 Impact on standard INQUIRY data................................ 7 82 5. SCSI Commands................................................... 8 83 5.1 SCSI Command Additions .................................. 8 84 5.1.1 Command Priority (byte 2) ........................... 9 85 5.2 SCSI Response Additions ................................. 9 86 5.2.1 Status Qualifier ................................... 10 87 5.2.2 Data Segment - Sense and Response Data Segment ..... 10 88 6. Task Management Functions...................................... 11 89 6.1 Existing Task Management Functions ..................... 11 90 6.2 Task Management Function Additions ..................... 12 91 6.2.1 LUN field .......................................... 14 92 6.2.2 Referenced Task Tag ................................ 14 93 6.2.3 RefCmdSN ........................................... 14 94 6.3 Task Management Function Responses ..................... 14 95 6.3.1 Task Management Function Response Additions ........ 16 96 6.4 Task Management Requests Affecting Multiple Tasks ...... 16 97 7. Login/Text Operational Text Keys............................... 17 98 7.1 New Operational Text Keys .............................. 17 99 7.1.1 iSCSIProtocolLevel ................................. 17 100 8. Security Considerations........................................ 18 101 9. IANA Considerations............................................ 18 102 10. References.................................................... 21 103 11. Acknowledgements.............................................. 22 104 1. Introduction 106 The original iSCSI protocol [RFC3720] was built based on the 107 [SAM2] model for SCSI. Several new features and capabilities 108 have been added to the SCSI Architecture Model in the intervening 109 years (at the time of publication of this document, SAM-5 was the 110 current version of the SCSI Architecture Model). This document 111 is not a complete revision of [RFC3720]. Instead, this document 112 is intended as a companion document to [draft-ietf-storm-iscsi- 113 cons-xx]; this document may also be used as a companion document 114 to the combination of [RFC3720] and [RFC5048], although both of 115 those RFCs have been obsolete by [draft-ietf-storm-iscsi-cons- 116 xx]. 118 -------------------------------------------------------- 119 RFC EDITORS NOTE: The above references to [draft-ietf-storm- 120 iscsi-cons-xx] should reference the RFC number assigned to 121 that document, and this note should be removed. 122 -------------------------------------------------------- 124 2. Definitions, Acronyms, and Document Summary 126 2.1 Definitions 128 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL 129 NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" 130 in this document are to be interpreted as described in 131 [RFC2119]. 133 2.2 Acronyms 135 ISID Initiator Session Identifier 136 LU Logical Unit 137 PDU Protocol Data Unit 138 SAM-4 SCSI Architecture Model - 4 (see [SAM4]) 139 SAM-5 SCSI Architecture Model - 5 (see [SAM5]) 140 TMF Task Management Function 142 2.3 New Semantics 144 This document specifies new iSCSI semantics. This section 145 summarizes the contents of the document. 147 Section 3: The mapping of iSCSI objects to SAM-5 objects 148 The iSCSI node may contain both initiator and 149 target capabilities. 151 Section 4: The protocol used to negotiate the use of the new 152 capabilities described in this document. 154 Section 5: New Command operations 155 The PRI field for SCSI command priority has been 156 added to the SCSI command PDU (see 5.1.1). 157 The Status Qualifier field has been added to the 158 SCSI response PDU (see 5.2.1). 159 Sense data may be returned (via autosense) for any 160 SCSI status, not just CHECK CONDITION (see 5.2.2). 162 Section 6: New Task Management Functions 163 Four new task management functions (QUERY TASK, 164 QUERY TASK SET, I_T NEXUS RESET, and QUERY 165 ASYNCHRONOUS EVENT have been added (see 6.3). 166 A new "function succeeded" response has been added 167 (see 6.4.2). 169 Section 7: New Negotiation key 170 A new negotiation key has been added to enable the 171 use of the new features in section 5 and section 6. 173 3. Terminology Mapping 175 The iSCSI model (defined in [RFC-cons]) uses different 176 terminology than the SCSI Architecture Model. In some cases, 177 iSCSI uses multiple terms to describe what in the SCSI 178 Architecture Model is described with a single term. The iSCSI 179 terms and SAM-5 terms are not necessarily equivalent, but rather, 180 the iSCSI terms represent examples of the objects or classes 181 described in SAM-5 as follows: 183 -------------------------------------------------------- 184 RFC EDITORS NOTE: The above reference to [RFC-cons] should 185 reference the RFC number assigned to [draft-ietf-storm-iscsi- 186 cons-xx], and this note should be removed. 187 -------------------------------------------------------- 189 +-----------------------------+---------------------------+ 190 | RFCxxx Terminology | SAM-5 Terminology | 191 +-----------------------------+---------------------------+ 192 | Network Entity | none | 193 +-----------------------------+---------------------------+ 194 | iSCSI Node | SCSI Device | 195 +-----------------------------+---------------------------+ 196 | iSCSI Name | SCSI Device Name | 197 +-----------------------------+---------------------------+ 198 | iSCSI Node Name | SCSI Device Name | 199 +-----------------------------+---------------------------+ 200 | iSCSI Initiator Node | SCSI Initiator Device | 201 +-----------------------------+---------------------------+ 202 | iSCSI Initiator Name | SCSI Device Name | 203 +-----------------------------+---------------------------+ 204 | iSCSI Initiator Port | SCSI Initiator Port | 205 | Identifier; (i.e., iSCSI | Identifier | 206 | Node Name + ,,,i, + ISID)*1| | 207 +-----------------------------+---------------------------+ 208 | iSCSI Initiator Port Name; | SCSI Initiator Port Name | 209 | (i.e., iSCSI Node Name + | | 210 | ,,,i, + ISID)*1 | | 211 +-----------------------------+---------------------------+ 212 | iSCSI Target Node | SCSI Target Device | 213 +-----------------------------+---------------------------+ 214 | iSCSI Target Name | SCSI Device Name | 215 +-----------------------------+---------------------------+ 216 | iSCSI Target Port | SCSI Target Port | 217 | Identifier; (i.e., iSCSI | Identifier | 218 | Node Name + ,,,t, + | | 219 | Target Portal Group Tag)*1 | | 220 +-----------------------------+---------------------------+ 221 | iSCSI Target Port Name; | SCSI Target Port Name | 222 | (i.e., iSCSI Node Name + | | 223 | ,,,t, + Target Portal | | 224 | Group Tag)*1 | | 225 +-----------------------------+---------------------------+ 226 | iSCSI Target Portal Group | SCSI Target Port | 227 +-----------------------------+---------------------------+ 228 | iSCSI Initiator Name + | I_T Nexus Identifier | 229 | ',i,' + ISID + iSCSI | | 230 | Target Name + ',t,' + | | 231 | Target Portal Group Tag | | 232 +-----------------------------+---------------------------+ 233 | Target Portal Group Tag | Relative Port ID | 234 +-----------------------------+---------------------------+ 236 *1 The text encoding of the ISID value and the Target Portal 237 Group Tag value includes an initial ,,0X or ,,0x (see [RFC- 238 cons]). 240 -------------------------------------------------------- 241 RFC EDITORS NOTE: The above reference (in row 1) to [RFCxxx] 242 should reference this RFC, and this note should be removed. 244 The above reference to [RFC-cons] should reference the RFC 245 number assigned to [draft-ietf-storm-iscsi-cons-xx], and this 246 note should be removed. 247 -------------------------------------------------------- 249 The following diagram shows an example of a combination target 250 device and initiator device. Such a configuration may exist in a 251 target device that implements a SCSI Copy Manager. This example 252 shows how a session that shares Network Portals within a Portal 253 Group may be established (see Target Portal Group 1). In 254 addition, this example shows the Initiator using a different 255 Portal Group than the Target Portal Group, but the Initiator 256 Portal group sharing Network Portal A with the Target Portal 257 Group. 259 ----------------------------IP Network--------------------- 260 | | | 261 +----|---------------|-------+ +----|------------+ 262 | +----------+ +----------+ | | +----------+ | 263 | | Network | | Network | | | | Network | | 264 | | Portal A | | Portal B | | | | Portal A | | 265 | +----------+ +----------+ | | +----------+ | 266 | | Target | | | | Initiator | 267 | | Portal | | | | Portal | 268 | | Group 1 | | | | Group 2 | 269 +----|---------------|-------+ +----|------------+ 270 | | | 271 +----------|---------------|--------------------|--------------------+ 272 | +--------|---------------|----+ +-------------|------------------+ | 273 | |+-------|---------------|---+| |+------------|-----------------+| | 274 | ||iSCSI Session (Target side)|| ||iSCSI Session (Initiator side)|| | 275 | || || || || | 276 | || (TSIH = 56) || || (SSID = 48) || | 277 | |+---------------------------+| |+------------------------------+| | 278 | | | | | | 279 | | iSCSI Target Node | | iSCSI Initiator Node | | 280 | +-----------------------------+ +--------------------------------+ | 281 | iSCSI Node | 282 | (within Network Entity, not shown) | 283 +--------------------------------------------------------------------+ 284 4. New Feature Use 286 4.1 Negotiation of New Feature Use 288 The iSCSIProtocolLevel operational text key (see 7.1.1) 289 containing a value of "2" MUST be negotiated to enable the use of 290 features described in this RFC. 292 The iSCSIProtocolLevel operational text key (see 7.1.1) 293 containing a value of "2" MUST be negotiated to enable the use of 294 features described in this RFC. This is an iSCSI negotiation 295 mechanism that enabled iSCSI support for corresponding SCSI 296 capabilities (see [SAM5] and [SPC4]. For this reason, 297 negotiation of this key to a value of "2" is necessary, but not 298 sufficient for hse of the SCSI capabilities enabled by the iSCSI 299 features in this RFC. 301 For example, an iSCSI implementation may negotiate this new key 302 to "2" but respond to the new task management functions (see 6.3) 303 with a "Task management function not supported" (which indicates 304 a SCSI error that prevents the function from being performed). 305 In contrast, if the key is negotiated to "2", an iSCSI 306 implementation MUST NOT reject a task management function request 307 PDU that requests one of the new task management functions (as 308 such a reject would report an iSCSI protocol error). 310 4.2 Impact on standard INQUIRY data 312 The negotiated value of the iSCSIProtocolLevel key is an 313 increment from the base iSCSI version descriptor value 314 (0960h)(see [SPC4]). If the SCSI device server returns an iSCSI 315 version descriptor in the standard INQUIRY data, then the value 316 returned in that iSCSI version descriptor MUST be set to the sum 317 of the base value (0960h) plus the negotiated value of the 318 iSCSIProtocolLevel key (for example, if the negotiated 319 iSCSIProtocolLevel=2, then if an iSCSI version descriptor is 320 returned in the standard INQUIRY data it is set to 0962h). 322 5. SCSI Commands 324 5.1 SCSI Command Additions 326 The format of the SCSI Command PDU is: 328 Byte/ 0 | 1 | 2 | 3 | 329 / | | | | 330 |0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7| 331 +---------------+---------------+---------------+---------------+ 332 0|.|I| 0x01 |F|R|W|. .|ATTR | PRI | Reserved | 333 +---------------+---------------+---------------+---------------+ 334 4|TotalAHSLength | DataSegmentLength | 335 +---------------+---------------+---------------+---------------+ 336 8| Logical Unit Number (LUN) | 337 + + 338 12| | 339 +---------------+---------------+---------------+---------------+ 340 16| Initiator Task Tag | 341 +---------------+---------------+---------------+---------------+ 342 20| Expected Data Transfer Length | 343 +---------------+---------------+---------------+---------------+ 344 24| CmdSN | 345 +---------------+---------------+---------------+---------------+ 346 28| ExpStatSN | 347 +---------------+---------------+---------------+---------------+ 348 32/ SCSI Command Descriptor Block (CDB) / 349 +/ / 350 +---------------+---------------+---------------+---------------+ 351 48/ AHS (Optional) / 352 +---------------+---------------+---------------+---------------+ 353 x/ Header Digest (Optional) / 354 +---------------+---------------+---------------+---------------+ 355 y/ (DataSegment, Command Data) (Optional) / 356 +/ / 357 +---------------+---------------+---------------+---------------+ 358 z/ Data Digest (Optional) / 359 +---------------+---------------+---------------+---------------+ 361 The SCSI Command PDU above is duplicated from [RFC-cons] for 362 reference to show the PRI field. For any field other than the 363 PRI field, the text in [RFC-cons] supersedes the text in section 364 5.1 of this document in the event the two documents conflict. 366 -------------------------------------------------------- 367 RFC EDITORS NOTE: The above references to [RFC-cons] should 368 reference the RFC number assigned to [draft-ietf-storm-iscsi- 369 cons-xx], and this note should be removed. 370 -------------------------------------------------------- 372 5.1.1 Command Priority (byte 2) 374 The Command Priority (PRI) is a four (4) bit field that specifies 375 the relative scheduling importance of this task in relation to 376 other SIMPLE tasks already in the task set (see [SAM4]). 378 Section 11, iSCSI PDU Formats of [RFC-cons], requires that 379 senders set this field to zero. A sender MUST NOT set this field 380 to a value other than zero unless the iSCSIProtocolLevel text key 381 defined in section 7.1.1 has been negotiated on the session with 382 a value of "2". 384 -------------------------------------------------------- 385 RFC EDITORS NOTE: The above reference to [RFC-cons] should 386 reference the RFC number assigned to [draft-ietf-storm-iscsi- 387 cons-xx], and this note should be removed. 388 -------------------------------------------------------- 390 This field MUST be ignored by iSCSI targets unless the 391 iSCSIProtocolLevel text key with a value of "2" as defined in 392 section 7.1.1 was negotiated on the session. 394 See [SAM5] for special considerations on the use of the priority 395 field. 397 5.2 SCSI Response Additions 399 The format of the SCSI Response PDU is: 401 Byte/ 0 | 1 | 2 | 3 | 402 / | | | | 403 |0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7| 404 +---------------+---------------+---------------+---------------+ 405 0|.|.| 0x21 |1|. .|o|u|O|U|.| Response | Status | 406 +---------------+---------------+---------------+---------------+ 407 4|TotalAHSLength | DataSegmentLength | 408 +---------------+---------------+---------------+---------------+ 409 8| Status Qualifier | Reserved | 410 +---------------+---------------+---------------+---------------+ 411 12| Reserved | 412 +---------------+---------------+---------------+---------------+ 413 16| Initiator Task Tag | 414 +---------------+---------------+---------------+---------------+ 415 20| SNACK Tag or Reserved | 416 +---------------+---------------+---------------+---------------+ 417 24| StatSN | 418 +---------------+---------------+---------------+---------------+ 419 28| ExpCmdSN | 420 +---------------+---------------+---------------+---------------+ 421 32| MaxCmdSN | 422 +---------------+---------------+---------------+---------------+ 423 36| ExpDataSN or Reserved | 424 +---------------+---------------+---------------+---------------+ 425 40| Bidirectional Read Residual Count or Reserved | 426 +---------------+---------------+---------------+---------------+ 427 44| Residual Count or Reserved | 428 +---------------+---------------+---------------+---------------+ 429 48| Header-Digest (Optional) | 430 +---------------+---------------+---------------+---------------+ 431 / Data Segment (Optional) / 432 +/ / 433 +---------------+---------------+---------------+---------------+ 434 | Data-Digest (Optional) | 435 +---------------+---------------+---------------+---------------+ 437 The SCSI Response PDU above is duplicated from [RFC-cons] for 438 reference to show the Status Qualifier field. For any field 439 other than the Status field, the Status Qualifier field, and the 440 Data Segment - Sense and Response Data Segment field, the text in 441 [RFC-cons] supersedes the text in section 5.2 of this document in 442 the event the two documents conflict. 444 -------------------------------------------------------- 445 RFC EDITORS NOTE: The above references to [RFC-cons] should 446 reference the RFC number assigned to [draft-ietf-storm-iscsi- 447 cons-xx], and this note should be removed. 448 -------------------------------------------------------- 450 5.2.1 Status Qualifier 452 The Status Qualifier provides additional status information (see 453 [SAM4]). 455 As defined in Section 11, iSCSI PDU Formats of [RFC-cons], 456 compliant senders already set this field to zero. Compliant 457 senders MUST NOT set this field to a value other than zero unless 458 the iSCSIProtocolLevel text key with a value of "2" as defined in 459 section 7.1.1 was negotiated on the session. 461 -------------------------------------------------------- 462 RFC EDITORS NOTE: The above reference to [RFC-cons] should 463 reference the RFC number assigned to [draft-ietf-storm-iscsi- 464 cons-xx], and this note should be removed. 465 -------------------------------------------------------- 467 This field MUST be ignored by receivers unless the 468 iSCSIProtocolLevel text key with a value of "2" as defined in 469 section 7.1.1 was negotiated on the session. 471 5.2.2 Data Segment - Sense and Response Data Segment 473 Section 11.4.7 of [RFC-cons] specifies that iSCSI targets MUST 474 support and enable autosense. If Status is CHECK CONDITION 475 (0x02), then the Data Segment MUST contain sense data for the 476 failed command. While [RFC-cons] does not make any statements 477 about the state of the Data Segment when the Status is not CHECK 478 CONDITION (0x02)(i.e., the Data Segment is not prohibited from 479 containing sense data when the Status is not CHECK CONDITION), 480 negotiation of the iSCSIProtocolLevel text key with a value of 481 "2" as defined in section 7.1.1 explicitly indicates that the 482 Data Segment MAY contain sense data at any time, no matter what 483 value is set in the Status field. 485 -------------------------------------------------------- 486 RFC EDITORS NOTE: The above references to [RFC-cons] should 487 reference the RFC number assigned to [draft-ietf-storm-iscsi- 488 cons-xx], and this note should be removed. 489 -------------------------------------------------------- 491 6. Task Management Functions 493 6.1 Task Management Function Request PDU 495 Byte/ 0 | 1 | 2 | 3 | 496 / | | | | 497 |0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7| 498 +---------------+---------------+---------------+---------------+ 499 0|.|I| 0x02 |1| Function | Reserved | 500 +---------------+---------------+---------------+---------------+ 501 4|TotalAHSLength | DataSegmentLength | 502 +---------------+---------------+---------------+---------------+ 503 8| Logical Unit Number (LUN) | 504 + + 505 12| | 506 +---------------+---------------+---------------+---------------+ 507 16| Initiator Task Tag | 508 +---------------+---------------+---------------+---------------+ 509 20| Referenced Task Tag or 0xffffffff | 510 +---------------+---------------+---------------+---------------+ 511 24| CmdSN | 512 +---------------+---------------+---------------+---------------+ 513 28| ExpStatSN | 514 +---------------+---------------+---------------+---------------+ 515 32| RefCmdSN or Reserved | 516 +---------------+---------------+---------------+---------------+ 517 36| ExpDataSN or Reserved | 518 +---------------+---------------+---------------+---------------+ 519 40| Reserved / 520 +/ / 521 +---------------+---------------+---------------+---------------+ 522 48| Header-Digest (Optional) | 523 +---------------+---------------+---------------+---------------+ 525 The Task Management Function Request PDU above is duplicated from 526 [RFC-cons] for reference only. [RFC-cons] supersedes the text in 528 section 6.1 and 6.2 of this document in the event the two 529 documents conflict. 531 -------------------------------------------------------- 532 RFC EDITORS NOTE: The above references to [RFC-cons] should 533 reference the RFC number assigned to [draft-ietf-storm-iscsi- 534 cons-xx], and this note should be removed. 535 -------------------------------------------------------- 537 6.2 Existing Task Management Functions 539 Section 11.5 of [RFC-cons] defines the semantics used to request 540 SCSI Task Management Functions be performed. The following task 541 management functions are defined: 543 1 - ABORT TASK 544 2 - ABORT TASK SET 545 3 - CLEAR ACA 546 4 - CLEAR TASK SET 547 5 - LOGICAL UNIT RESET 548 6 - TARGET WARM RESET 549 7 - TARGET COLD RESET 550 8 - TASK REASSIGN 552 -------------------------------------------------------- 553 RFC EDITORS NOTE: The above references to [RFC-cons] should 554 reference the RFC number assigned to [draft-ietf-storm-iscsi- 555 cons-xx], and this note should be removed. 556 -------------------------------------------------------- 558 6.3 Task Management Function Additions 560 Additional task Management function codes are listed below. For 561 a more detailed description of SCSI task management, see [SAM5]. 563 9 - QUERY TASK - determines if the command identified by the 564 Referenced Task Tag field is present in the task set. 566 10 - QUERY TASK SET - determine if any command is present in 567 the task set for the I_T_L Nexus on which the task management 568 function was received. 570 11 - I_T NEXUS RESET - perform an I_T nexus loss function (see 571 [SAM5]) for the I_T nexus on which the task management 572 function was received. 574 12 - QUERY ASYNCHRONOUS EVENT - determine if there is a unit 575 attention condition or a deferred error pending for the I_T_L 576 nexus on which the task management function was received. 578 These task management function requests MUST NOT be sent unless 579 the iSCSIProtocolLevel text key with a value of "2" as defined in 580 section 7.1.1 was negotiated on the session. 582 Any compliant initiator that sends any of the new task management 583 functions defined in this section MUST also support all new task 584 management function responses (as specified in section 6.4.2). 586 For all of the task management functions detailed in this 587 section, the Task Management function response MUST be returned 588 as detailed in section 6.4. 590 The iSCSI target MUST ensure that no responses for the commands 591 covered by a task management function are sent to the iSCSI 592 initiator port after the Task Management response except for a 593 commands covered by a TASK REASSIGN, QUERY TASK, or QUERY TASK 594 SET. 596 If a QUERY TASK is issued for a task created by an immediate 597 command then RefCmdSN MUST be that of the Task Management request 598 itself (i.e., CmdSN and RefCmdSN are equal); otherwise RefCmdSN 599 MUST be set to the CmdSN of the task to be queried (lower than 600 CmdSN). 602 If the connection is still active (it is not undergoing an 603 implicit or explicit logout), QUERY TASK MUST be issued on the 604 same connection to which the task to be queried is allegiant at 605 the time the Task Management request is issued. If the 606 connection is implicitly or explicitly logged out (i.e., no other 607 request will be issued on the failing connection and no other 608 response will be received on the failing connection), then a 609 QUERY TASK function request may be issued on another connection. 610 This Task Management request will then establish a new allegiance 611 for the command being queried. 613 At the target a QUERY TASK function MUST NOT be executed on a 614 Task Management request; such a request MUST result in Task 615 Management response of "Function rejected". 617 For the I_T NEXUS RESET function, the target device MUST respond 618 to the function as defined in [SAM4]. Each logical unit 619 accessible via the receiving I_T NEXUS MUST behave as dictated by 620 the I_T nexus loss function in [SAM4] for the I_T nexus on which 621 the task management function was received. The target device 622 MUST drop all connections in the session over which this function 623 is received. Independent of the DefaultTime2Wait and 624 DefaultTime2Retain value applicable to the session over which 625 this function is received, the target device MUST consider each 626 participating connection in the session to have immediately timed 627 out, leading to FREE state. The resulting timeouts cause the 628 session timeout event defined in [RFC-cons], which in turn 629 triggers the I_T nexus loss notification to the SCSI layer as 630 described in [RFC-cons]. 632 -------------------------------------------------------- 633 RFC EDITORS NOTE: The above references to [RFC-cons] should 634 reference the RFC number assigned to [draft-ietf-storm-iscsi- 635 cons-xx], and this note should be removed. 636 -------------------------------------------------------- 638 6.3.1 LUN field 640 This field is required for functions that address a specific LU 641 (i.e., ABORT TASK, CLEAR TASK SET, ABORT TASK SET, CLEAR ACA, 642 LOGICAL UNIT RESET, QUERY TASK, QUERY TASK SET, and QUERY 643 ASYNCHRONOUS EVENT) and is reserved in all others. 645 6.3.2 Referenced Task Tag 647 The Initiator Task Tag of the task to be aborted for the ABORT 648 TASK function, reassigned for the TASK REASSIGN function, or 649 queried for the QUERY TASK function. For all other functions 650 this field MUST be set to the reserved value 0xffffffff. 652 6.3.3 RefCmdSN 654 If a QUERY TASK is issued for a task created by an immediate 655 command then RefCmdSN MUST be that of the Task Management request 656 itself (i.e., CmdSN and RefCmdSN are equal). 658 For a QUERY TASK of a task created by non-immediate command 659 RefCmdSN MUST be set to the CmdSN of the task identified by the 660 Referenced Task Tag field. Targets must use this field as 661 described in section 11.6.1 of [RFC-cons] when the task 662 identified by the Referenced Task Tag field is not in the task 663 set. 665 -------------------------------------------------------- 666 RFC EDITORS NOTE: The above references to [RFC-cons] should 667 reference the RFC number assigned to [draft-ietf-storm-iscsi- 668 cons-xx], and this note should be removed. 669 -------------------------------------------------------- 671 6.4 Task Management Function Responses 673 6.4.1 Task Management Function Response PDU 675 Byte/ 0 | 1 | 2 | 3 | 676 / | | | | 677 |0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7|0 1 2 3 4 5 6 7| 678 +---------------+---------------+---------------+---------------+ 679 0|.|.| 0x22 |1| Reserved | Response | Reserved | 680 +---------------+---------------+---------------+---------------+ 681 4|TotalAHSLength | DataSegmentLength | 682 +-----------------------------------------------+---------------+ 683 8| Additional Response Information | Reserved | 684 +-----------------------------------------------+---------------+ 685 12| Reserved | 686 +---------------+---------------+---------------+---------------+ 687 16| Initiator Task Tag | 688 +---------------+---------------+---------------+---------------+ 689 20| Reserved | 690 +---------------+---------------+---------------+---------------+ 691 24| StatSN | 692 +---------------+---------------+---------------+---------------+ 693 28| ExpCmdSN | 694 +---------------+---------------+---------------+---------------+ 695 32| MaxCmdSN | 696 +---------------+---------------+---------------+---------------+ 697 36/ Reserved / 698 +/ / 699 +---------------+---------------+---------------+---------------+ 700 48| Header-Digest (Optional) | 701 +---------------+---------------+---------------+---------------+ 703 Section 11.6 of [RFC-cons] defines the semantics used for 704 responses to SCSI Task Management Functions. The following 705 responses are defined in [RFC-cons]: 707 0 - Function Complete. 708 1 - Task does not exist. 709 2 - LUN does not exist. 710 3 - Task still allegiant. 711 4 - Task allegiance reassignment not supported. 712 5 - Task management function not supported. 713 6 - Function authorization failed. 714 255 - Function rejected. 716 The Task Management Function Response PDU above and the list of 717 task management function responses above are duplicated from 718 [RFC-cons] for reference only. [RFC-cons] supersedes the text in 719 section 6.4.1 of this document in the event the two documents 720 conflict. 722 -------------------------------------------------------- 723 RFC EDITORS NOTE: The above references to [RFC-cons] should 724 reference the RFC number assigned to [draft-ietf-storm-iscsi- 725 cons-xx], and this note should be removed. 726 -------------------------------------------------------- 728 Responses to new task management functions (see 6.4.2) are listed 729 below. In addition, a new task Management response is listed 730 below. For a more detailed description of SCSI task management 731 responses, see [SAM5]. 733 For the functions QUERY TASK, QUERY TASK SET, I_T NEXUS RESET, 734 and QUERY ASYNCHRONOUS EVENT, the target performs the requested 735 Task Management function and sends a Task Management response 736 back to the initiator. 738 6.4.2 Task Management Function Response Additions 740 The new response is listed below: 742 7 - Function succeeded. 744 In symbolic terms Response value 7 maps to the SCSI service 745 response of FUNCTION SUCCEEDED in [SAM4]. 747 The task management function response of "Function succeeded" 748 MUST be supported by an initiator that sends any of the new task 749 management functions (see 6.3). 751 For the QUERY TASK function, if the specified task is in the task 752 set, then the logical unit returns a Response value of Function 753 succeeded and additional response information is returned as 754 specified in [SAM5]. If the specified task is not in the task 755 set, then the logical unit returns a Response value of Function 756 complete. 758 For the QUERY TASK SET function, if there is any command present 759 in the task set from the specified I_T_L nexus, then the logical 760 unit returns a Response value of Function succeeded. If there 761 are no commands present in the task set from the specified I_T_L 762 nexus, then the logical unit returns a Response value of Function 763 complete. 765 For the I_T NEXUS RESET function, after completion of the events 766 described in section 6.3 for this function, the logical unit 767 returns a Response value of Function complete. However, because 768 the target drops all connections, the Service Response (defined 769 by [SAM4]) for this SCSI task management function may not be 770 reliably delivered to the issuing initiator port. 772 For the QUERY ASYNCHRONOUS EVENT, if there is a unit attention 773 condition or deferred error pending for the specified I_T_L 774 nexus, then the logical unit returns a Response value of Function 775 succeeded and additional response information is returned as 776 specified in [SAM5]. If there is no unit attention or deferred 777 error pending for the specified I_T_L nexus then the logical unit 778 returns a Response value of Function complete. 780 6.5 Task Management Requests Affecting Multiple Tasks 782 Section 4.1 of [RFC5048] defines the notion of "affected tasks" 783 in multi-task abort scenarios. This section adds to the list 784 include in that section by defining the tasks affected by the I_T 785 NEXUS RESET function. 787 I_T NEXUS RESET: All outstanding tasks received on the I_T 788 nexus on which the function request was received for all 789 logical units accessible to the I_T nexus. 791 Section 4.1.2 of [RFC5048] and section 4.1.3 of [RFC5048] 792 identify semantics for task management functions that involve 793 multi-task abort operations. If an iSCSI implementation supports 794 the I_T NEXUS RESET function, it MUST also support the protocol 795 behavior as defined in those sections and follow the sequence of 796 actions as described in those sections when processing the I_T 797 NEXUS RESET function. 799 7. Login/Text Operational Text Keys 801 7.1 New Operational Text Keys 803 7.1.1 iSCSIProtocolLevel 805 Use: LO, IO 806 Irrelevant when: SessionType = Discovery 807 Senders: Initiator and Target 808 Scope: SW 810 iSCSIProtocolLevel= 812 Default is 1. 813 Result function is Minimum. 815 This key is used to negotiate the use of iSCSI features that 816 require different levels of protocol support (e.g., PDU formats, 817 end node semantics) for proper operation. 819 Negotiation of the iSCSIProtocolLevel key to a value 820 corresponding to an RFC indicates that both negotiating parties 821 are compliant to the RFC in question, and agree to support the 822 corresponding PDU formats and semantics on that iSCSI session. 823 An operational value of iSCSI ProtocolLevel = "x" on an iSCSI 824 session requires that the iSCSI protocol semantics on that iSCSI 825 session be a logical superset of the capabilities in all RFCs 826 that have claimed values of an iSCSIProtocolLevel less than "x". 828 An iSCSIProtocolLevel key negotiated to "0" indicates that the 829 implementation does not claim a specific iSCSI protocol level. 831 An iSCSIProtocolLevel key negotiated to "1" indicates that the 832 implementation claims compliance with [RFC-cons]. 834 -------------------------------------------------------- 835 RFC EDITORS NOTE: The above reference to [RFC-cons] should 836 reference the RFC number assigned to [draft-ietf-storm-iscsi- 837 cons-xx], and this note should be removed. 838 -------------------------------------------------------- 840 An iSCSIProtocolLevel key negotiated to "2" is required to enable 841 use of features defined in this RFC. 843 If the negotiation answer is ignored by the acceptor, or the 844 answer from the remote iSCSI end point is key=NotUnderstood, then 845 the features defined in this RFC, and the features defined in any 846 RFC requiring a key value greater than "2" MUST NOT be used. 848 8. Security Considerations 850 Poor implementations (those that do not observe the requirements 851 described in [SAM5]) may allow the priority field (see 5.1.1) to 852 be used to create a denial of service attack. 854 All the iSCSI-related security text in [RFC3723] is also directly 855 applicable to this document. 857 -------------------------------------------------------- 858 RFC EDITORS NOTE: The above reference to [RFC-cons] should 859 reference the RFC number assigned to [draft-ietf-storm-iscsi- 860 cons-xx], and this note should be removed. 861 -------------------------------------------------------- 863 9. IANA Considerations 865 This document modifies or creates a number of iSCSI-related 866 registries. The following iSCSI-related registries are modified: 868 1. iSCSI Task Management Functions Codes 870 Name of the existing registry: "iSCSI TMF Codes" 872 The name of this registry should be changed to: "iSCSI Task 873 Management Function Codes". 875 Additional entries: 877 9, QUERY TASK, [RFCxxx] 879 10, QUERY TASK SET, [RFCxxx] 881 11, I_T NEXUS RESET, [RFCxxx] 883 12, QUERY ASYNCHRONOUS EVENT, [RFCxxx] 885 --------------------------------------------------------- 887 RFC EDITORS NOTE: The above reference to [RFCxxx] should 888 reference this RFC, and this note should be removed. 889 --------------------------------------------------------- 891 2. iSCSI Login/Text Keys 893 Name of the existing registry: "iSCSI Text Keys" 895 Fields to record in the registry: Assigned value and its 896 associated RFC reference: 898 iSCSIProtocolLevel, [RFCxxx] 900 --------------------------------------------------------- 901 RFC EDITORS NOTE: The above references to [RFCxxx] should 902 reference this RFC, and this note should be removed. 903 --------------------------------------------------------- 905 This document creates the following iSCSI-related registries for 906 IANA to manage. 908 3. iSCSI Protocol Level 910 Name of new registry: "iSCSI Protocol Level" 912 Namespace details: Numerical values from 0 to 31 914 Information that must be provided to assign a new value: An 915 IESG-approved standards track specification defining the 916 semantics and interoperability requirements of the proposed 917 new value and the fields to be recorded in the registry. 919 Assignment policy: 921 The assignments of these values must be coordinated with the 922 INCITS T10 committee; therefore review by an expert that 923 maintains an association with that committee is required prior 924 to IESG approval of the associated specification. After 925 creation of the registry, values are to be assigned 926 sequentially (for example, any value greater than 4 will not 927 be assigned until after the value 4 has been assigned). 929 Special care must be taken in the assignment of new values in 930 this registry. Compatibility and interoperability will be 931 adversely impacted if proper care is not exercised. Features 932 using this key are expected to be cumulative. For example, 933 since this draft explicitly lists only value 2 for the 934 features listed in this draft, it is expected that a new RFC 935 assigning value 3 will also have the features listed in this 936 RFC and therefore such an RFC is expected to either revise or 937 replace this RFC. Assignments that do not follow this policy 938 should be reviewed and approved by the INCITS T10 committee. 940 3-31: range reserved by IANA for assignment in this registry. 942 Fields to record in the registry: Assigned value, and its 943 associated RFC reference. 945 0, [RFCxxx] 947 1, [RFC-cons] 949 2, [RFCxxx] 951 --------------------------------------------------------- 952 RFC EDITORS NOTE: The above references to [RFCxxx] should 953 reference this RFC, and this note should be removed. The 954 above references to [RFC-cons] should reference the [draft- 955 ietf-storm-iscsi-cons-xx] document, and this note should be 956 removed. 958 --------------------------------------------------------- 960 Allocation Policy: 962 Expert review ([IANA]) and Standards Action ([IANA]) 964 4. iSCSI Task Management Response Codes 966 Name of new registry: "iSCSI Task Management Function Response 967 Codes" 969 Namespace details: Numerical values that can fit in 8 bits. 971 Information that must be provided to assign a new value: An 972 IESG-approved specification defining the semantics and 973 interoperability requirements of the proposed new value and 974 the fields to be recorded in the registry. 976 Assignment policy: 978 If the requested value is not already assigned, it may be 979 assigned to the requester. 981 8-254: Range reserved by iANA for assignment in this registry. 983 Fields to record in the registry: Assigned value, Operation 984 Name, and its associated RFC reference. 986 0x0, Function complete, [RFC-cons] 988 0x1, Task does not exist, [RFC-cons] 990 0x2, LUN does not exist, [RFC-cons] 991 0x3, Task still allegiant, [RFC-cons] 993 0x4, Task allegiance reassignment not supported, [RFC-cons] 995 0x5, Task management function not supported, [RFC-cons] 997 0x6, Function authorization failed, [RFC-cons] 999 0x7, Function succeeded, [RFCxxx] 1001 255, Function rejected, [RFC-cons] 1003 ------------------------------------------------------------ 1004 RFC EDITORS NOTE: The above reference to [RFCxxx] should 1005 reference this RFC, and this note should be removed. 1007 The above references to [RFC-cons] should reference the 1008 [draft-ietf-storm-iscsi-cons-xx] document, and this note 1009 should be removed. 1010 ------------------------------------------------------------ 1012 Allocation Policy: 1014 Standards Action ([IANA]) 1016 10. References 1018 10.1 Normative References 1020 [RFC2119] Bradner, S. "Key Words for use in RFCs to Indicate 1021 Requirement Levels", BCP 14, RFC 2119, March 1997. 1023 [RFC3723] Aboba, B., Tseng, J., Walker, J., Rangan, V., and 1024 Travostino, F., "Securing Block Storage Protocols 1025 over IP", RFC 3723, April 2004. 1027 [RFC5048] Chadalapaka, M., "Internet Small Computer System 1028 Interface (iSCSI) Corrections and Clarifications", 1029 RFC 5048, October 2007. 1031 [draft-ietf-storm-iscsi-cons-xx] Chadalapaka, M., Satran, J., 1032 Kalman, M., "iSCSI Protocol (consolidated)", RFC xxx, 1033 Date 2011. 1035 ------------------------------------------------------------ 1036 RFC EDITORS NOTE: The above references to [draft-ietf-storm- 1037 iscsi-cons-xx] and [RFCxxx] should reference the RFC number 1038 assigned to that draft, and this note should be removed. 1039 ------------------------------------------------------------ 1041 [IANA] Narten, T. and H. Alvestrand, "Guidelines for Writing 1042 an IANA Considerations Section in RFCs", BCP 26, RFC 1043 5226, May 2008. 1045 [SAM2] T10/1157D, SCSI Architecture Model - 2 (SAM-2). 1047 [SAM4] ISO/IEC 14776-414, SCSI Architecture Model - 4 (SAM- 1048 4). 1050 [SAM5] T10/2104D rev r04, SCSI Architecture Model - 5 (SAM- 1051 5), Committee Draft. 1053 [SPC4] T10/1731D rev r36, SCSI Primary Commands - 4 (SPC-4), 1054 Committee Draft. 1056 10.2 Informative References 1058 [RFC3720] Satran, J., Meth, K., Sapuntzakis, C., Chadalapaka, 1059 M., and E. Zeidner, "Internet Small Computer Systems 1060 Interface (iSCSI)", RFC 3720, April 2004. 1062 10.3 Additional Reference Sources 1064 For more information on the SCSI Architecture Model and SCSI 1065 Primary Commands - 4, contact the INCITS T10 Technical Committee 1066 for SCSI Storage Interfaces at http://www.t10.org. 1068 11. Acknowledgements 1070 The Storage Maintenance (STORM) Working Group in the Transport 1071 Area of the IETF has been responsible for defining these 1072 additions to the iSCSI protocol (apart from other relevant IP 1073 Storage protocols). The editor acknowledges the contributions of 1074 the entire working group. 1075 The following individuals directly contributed to identifying 1076 [RFCxxx] issues and/or suggesting resolutions to the issues 1077 clarified in this document: David Black, Rob Elliott. This 1078 document benefited from all of these contributions. 1079 ------------------------------------------------------------ 1080 RFC EDITORS NOTE: The above reference to [RFCxxx] should 1081 reference this RFC, and this note should be removed. 1082 ------------------------------------------------------------ 1084 Author's Addresses 1086 Frederick Knight 1087 7301 Kit Creek Road 1088 P.O. Box 13917 1089 Research Triangle Park, NC 27709, USA 1090 Phone: +1-919-476-5362 1091 Email: knight@netapp.com 1093 Mallikarjun Chadalapaka 1094 Microsoft 1095 One Microsoft Way 1096 Redmond, WA 98052 USA 1097 Email: cbm@chadalapaka.com