Storage Maintenance (StorM) Working Group F. Knight Internet Draft NetApp Intended status: Standards Track M. Chadalapaka Expires: June 2010 Hewlett-Packard Co. Updates: 3720, 5048 December 2009 Internet Small Computer Systems Interface (iSCSI) Update draft-ietf-storm-iscsi-sam-00.txt Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. This document may contain material from IETF Documents or IETF Contributions published or made publicly available before November 10, 2008. The person(s) controlling the copyright in some of this material may not have granted the IETF Trust the right to allow modifications of such material outside the IETF Standards Process. Without obtaining an adequate license from the person(s) controlling the copyright in such materials, this document may not be modified outside the IETF Standards Process, and derivative works of it may not be created outside the IETF Standards Process, except to format it for publication as an RFC or to translate it into languages other than English. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet- Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/1id-abstracts.html. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on June 10, 2010. Copyright Notice Copyright (c) 2009 IETF Trust and the persons identified as the document authors. All rights reserved. Knight, et al. Expires June 10, 2010 [Page 1] Internet-Draft iSCSI Update December 09 This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents in effect on the date of publication of this document (http://trustee.ietf.org/license- info). Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Abstract Internet Small Computer Systems Interface (iSCSI) is a SCSI transport protocol that maps the SCSI family of protocols onto TCP/IP. RFC 3720 defines the iSCSI protocol. The current iSCSI protocol (RFC 3720 and RFC 5048) is based on the SAM-2 version of the SCSI family of protocols). This document defines additions and changes to the iSCSI protocol to enabled additional features that were added to the SCSI family of protocols through SAM-3, SAM-4, and SAM-5. This document updates RFC 3720 and RFC 5048 and the text in this document supersedes the text in RFC 3720 and RFC 5048 when the two differ. Knight, et al. Expires June 10, 2010 Page 2 Internet-Draft iSCSI Update December 09 Table of Contents 1 Introduction.................................................... 4 2 Definitions, Acronyms, and Document Summary..................... 4 2.1 Definitions .............................................. 4 2.2 Acronyms ................................................. 4 2.3 New Semantics ............................................ 5 3 UML Conventions................................................. 5 3.2 Multiplicity notation .................................... 5 3.3 Class diagram conventions ................................ 6 3.4 Class diagram notation for associations .................. 6 3.5 Class diagram notation for aggregations .................. 7 3.6 Class diagram notation for generalizations ............... 8 4 iSCSI UML Model................................................. 9 5 Terminology Mapping............................................ 11 6 Negotiation of New Feature Use................................. 13 7 SCSI Commands.................................................. 13 7.1 SCSI Command Additions .................................. 13 7.1.1 Command Priority (byte 2) ........................... 13 7.2 SCSI Response Additions ................................. 15 7.2.1 Status Qualifier .................................... 15 7.2.2 Data Segment - Sense and Response Data Segment ...... 16 8 Task Management Functions...................................... 16 8.1 Existing Task Management Functions ...................... 16 8.2 Task Management Function Additions ...................... 16 8.2.1 LUN field ........................................... 18 8.2.2 Referenced Task Tag ................................. 18 8.2.3 RefCmdSN ............................................ 18 8.3 Task Management Function Responses ...................... 19 8.3.1 Task Management Function Response Additions ......... 20 8.4 Task Management Requests Affecting Multiple Tasks ....... 20 9 Login/Text Operational Text Keys............................... 21 9.1 New Operational Text Keys ............................... 21 9.1.1 PDUFormatForSAMUpdate ............................... 21 10 IANA Considerations ......................................... 22 11 Security Considerations ..................................... 22 12 References .................................................. 23 13 Acknowledgements ............................................ 24 Knight, et al. Expires June 10, 2010 Page 3 Internet-Draft iSCSI Update December 09 1 Introduction The original [RFC3720] was built based on the SAM-2 model for SCSI. Several new features and capabilities have been added to the SCSI Architecture Model in the intervening years (SAM5 is now the current version of the SCSI Architecture Model). This document is not a complete revision of [RFC3720]. Instead, this document is intended as a companion document to [RFC3720] and [RFC5048]. The text in this document, however, updates and supersedes the text in [RFC3720] and [RFC5048] whenever there is any conflict. 2 Definitions, Acronyms, and Document Summary 2.1 Definitions The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119]. - iSCSI Node: The iSCSI Node represents a single iSCSI initiator or a single iSCSI target or both. There are one or more iSCSI Nodes within a Network Entity. The iSCSI Node is accessible via one or more Network Portals. An iSCSI Node is identified by its iSCSI Name. The separation of the iSCSI Name from the addresses used by and for the iSCSI Node allows multiple iSCSI Nodes to use the same address, and the same iSCSI Node to use multiple addresses. 2.2 Acronyms SAM4 SCSI Architecture Model - 4 SAM5 SCSI Architecture Model - 5 SAM SAM4 or SAM5 UML Unified Modeling Language Knight, et al. Expires June 10, 2010 Page 4 Internet-Draft iSCSI Update December 09 2.3 New Semantics This document specifies new iSCSI semantics. This section summarizes the contents of the document. Section 3: UML Conventions Section 4: The UML diagram of the iSCSI objects Section 5: The mapping of iSCSI objects to SAM5 objects Section 6: The protocol used to negotiate the use of the new capabilities described in this document. Section 7: New Command operations Section 8: New Task Management Functions 3 UML Conventions 3.1 UML Conventions overview The SCSI Architecture Model (SAM) uses class diagrams and object diagrams with notation that is based on the Unified Modeling Language [UML]. Therefore, this document also uses UML to model the relationships for SCSI and iSCSI objects. A treatise on the graphical notation used in UML is beyond the scope of this document. However, given the use of ASCII drawing for UML static class diagrams, a description of the notational conventions used in this document is included in the remainder of this section. 3.2 Multiplicity notation Not specified The number of instances of an attribute is not specified. 1 One instance of the class or attribute exists. 0..* Zero or more instances of the class or attribute exist. 1..* One or more instances of the class or attribute exist. 0..1 Zero or one instance of the class or attribute exists. n..m n to m instances of the class or attribute exist (e.g., 2..8). x, n..m Multiple disjoint instances of the class or attribute exist (e.g., 2, 8..15). Knight, et al. Expires June 10, 2010 Page 5 Internet-Draft iSCSI Update December 09 3.3 Class diagram conventions +--------------+ +--------------+ +--------------+ | Class Name | | Class Name | | Class Name | +--------------+ +--------------+ +--------------+ | | | | +--------------+ +--------------+ | | +--------------+ The above three diagrams are examples of a class with no attributes and with no operations. +-------------------+ +-------------------+ | Class Name | | Class Name | +-------------------+ +-------------------+ | attribute 01[1] | | attribute 01[1] | | attribute 02[1] | | attribute 02[1] | +-------------------+ +-------------------+ | | +-------------------+ The above two diagrams are examples of a class with attributes and with no operations. +------------------------+ | Class Name | +------------------------+ | attribute 01[1..*] | | attribute 02[1] | +------------------------+ | operation 01() | | operation 02() | +------------------------+ The above diagram is an example of a class with attributes that have a specified multiplicity and operations. 3.4 Class diagram notation for associations +-----------------+ | Class A | +-----------------+ association_name +-----------------+ | attribute 01[1] |<------------------>| Class B | | attribute 02[1] | 1..* 0..1 +-----------------+ +-----------------+ | attribute 03[1] | | operation 1() | +-----------------+ +-----------------+ The above diagram is an example where Class A knows about Class B (i.e., read as "Class A association_name ClassB") and Class B knows about Class A (i.e., read as "Class B association_name Class A"). The use of association_name is optional. The Knight, et al. Expires June 10, 2010 Page 6 Internet-Draft iSCSI Update December 09 multiplicity notation (1..* and 0..1) indicate the number of instances of the object. +--------------------+ | Class A | +--------------------+ +--------------------+ | attribute 01[1] |<-------------| Class B | | attribute 02[1] | 1 0..1 +--------------------+ +--------------------+ | attribute 03[1] | | operation 1() | +--------------------+ +--------------------+ The above diagram is an example where Class B knows about Class A (i.e., read as "Class B knows about Class A") but Class A does not know about Class B. +----------------------+ | Class A | +----------------------+ +--------------------+ | attribute 01[1] |----------->| Class B | | attribute 02[1] | 0..* 1 +--------------------+ +----------------------+ | attribute 03[1] | | operation 1() | +--------------------+ +----------------------+ The above diagram is an example where Class A knows about Class B (i.e., read as "Class A knows about Class B") but Class B does not know about Class A. 3.5 Class diagram notation for aggregations +---------+ +--------+ | whole |o------------| part | +---------+ +--------+ The above diagram is an example where the part class is part of the whole class and may continue to exist even if the whole class is removed (i.e., read as "the whole contains the part"). +---------+ +--------+ | whole |@------------| part | +---------+ +--------+ The above diagram is an example where the part class is part of the whole class, shall only belong to one whole class, and shall not continue to exist if the whole class is removed (i.e., read as "the whole contains the part"). Knight, et al. Expires June 10, 2010 Page 7 Internet-Draft iSCSI Update December 09 +-------------+ | | +-------------+ | | + =(a)= + | | The above diagram is an example where there is a constraint between the associations where the (a) footnote describes the constraint. 3.6 Class diagram notation for generalizations +---------------+ | Superclass | +-------^-------+ /_\ | +---------------+ | Subclass | +---------------+ The above diagram is an example where the subclass is a kind of superclass. A subclass shares all the attributes and operations of the superclass (i.e., the subclass inherits from the superclass). Knight, et al. Expires June 10, 2010 Page 8 Internet-Draft iSCSI Update December 09 4 iSCSI UML Model +----------------+ | Network Entity | +----------------+ @ 1 @ 1 | | +---------------------+ | | | | | 0..* | +------------------+ | | iSCSI Node | | +------------------+ | @ @ | | | | +------------+ =(a)= +------------+ | | | | | 0..1 | 0..1 | +------------------------+ +----------------------+ | | iSCSI Target Node | | iSCSI Initiator Node | | +------------------------+ +----------------------+ | @ 1 @ 1 | +---------------+ | | 1..* | | 1..* | +-----------------------------+ | | Portal Group | | +-----------------------------+ | O 1 | | | | 1..* | 1..* +------------------------+ +-------------------| Network Portal | +------------------------+ (a) Each instance of an iSCSI Node class MUST contain one iSCSI Target Node instance or one iSCSI Initiator Node instance, or both. Knight, et al. Expires June 10, 2010 Page 9 Internet-Draft iSCSI Update December 09 +----------------+ | Network Entity | +----------------+ @ 1 @ 1 | | +-------------------+ +---------------------+ | | iSCSI Session | | | +-------------------+ | | 0..* | SSID[1] | | +--------------------+ | ISID[1] | | | iSCSI Node | +-------------------+ | +--------------------+ @ 1 | | iSCSI Node Name[1] | | | | Alias [0..1] | | 0..* | +--------------------+ +------------------+ | | | | iSCSI Connection | | +--------------------+ +------------------+ | @ 1 @ 1 | CID[1] | | | | +------------------+ | +------------+ ==(b)== +-----------+ | 0..* | | | | | | 1 | 1 | | +------------------------+ +------------------------+ | | | iSCSI Target Node | | iSCSI Initiator Node | | | +------------------------+ +------------------------+ | | | iSCSI Target name [1] | |iSCSI Initiator Name [1]| | | +------------------------+ +------------------------+ | | @ 1 @ 1 | | | | | | | 1..* | 1..* | | +--------------------------+ +------------------------+ | | | Target Portal Group | | Initiator Portal Group | | | +--------------------------+ +------------------------+ | | |Target Portal Group Tag[1]| | Portal group tag[1] | | | +--------------------------+ +------------------------+ | | o 1 o 1 | | | | | | +-----------+ +---------+ | | 1..* | | 1..* | | +-------------------------+ | | | Network Portal | | | +-------------------------+ | | 1..* | IP Address [1] | 1 | +-----------------| TCP Port [0..1] |<--------------------+ +-------------------------+ (b) Each instance of an iSCSI Node class MUST contain one iSCSI Target Node instance or one iSCSI Initiator Node instance, or both. Knight, et al. Expires June 10, 2010 Page 10 Internet-Draft iSCSI Update December 09 5 Terminology Mapping The iSCSI model (defined in [RFC3720]) uses different terminology than the SCSI Architecture Model. In some cases, iSCSI uses multiple terms to describe what in the SCSI Architecture Model is described with a single term. The iSCSI terms and SAM terms are not necessarily equivalent, but rather, the iSCSI terms represent examples of the objects or classes described in SAM as follows: +-----------------------------+---------------------------+ | RFCxxx Terminology | SAM Terminology | +-----------------------------+---------------------------+ | Network Entity | none | +-----------------------------+---------------------------+ | iSCSI Node | SCSI Device | +-----------------------------+---------------------------+ | iSCSI Name | SCSI Device Name | +-----------------------------+---------------------------+ | iSCSI Node Name | SCSI Device Name | +-----------------------------+---------------------------+ | iSCSI Initiator Node | SCSI Initiator Device | +-----------------------------+---------------------------+ | iSCSI Initiator Name | SCSI Device Name | +-----------------------------+---------------------------+ | iSCSI Initiator Port Name | SCSI Initiator Port Name | | iSCSI Node Name + `,i,' + | | | ISID | | +-----------------------------+---------------------------+ | iSCSI Target Node | SCSI Target Device | +-----------------------------+---------------------------+ | iSCSI Target Name | SCSI Device Name | +-----------------------------+---------------------------+ | iSCSI Target Port Name | SCSI Target Port Name | | iSCSI Node Name + `,t,' + | | | Target Portal Group Tag | | +-----------------------------+---------------------------+ | iSCSI Target Portal Group | SCSI Target Port | +-----------------------------+---------------------------+ | iSCSI Initiator Node + | SCSI Initiator Port | | active ISID | | +-----------------------------+---------------------------+ | iSCSI Initiator Name + | I_T Nexus | | `,i,' + ISID, iSCSI Target | | | Name + `,t,' + Portal | | | Group Tag | | +-----------------------------+---------------------------+ | Target Portal Group Tag | Relative Port ID | +-----------------------------+---------------------------+ Knight, et al. Expires June 10, 2010 Page 11 Internet-Draft iSCSI Update December 09 -------------------------------------------------------- RFC EDITORS NOTE: The above reference to [RFCxxx] should reference this RFC, and this note should be removed. -------------------------------------------------------- The following diagram shows an example of a combination target device and initiator device. Such a configuration may exist in a target device that implements a SCSI Copy Manager. This example shows how a session that shares Network Portals within a Portal Group may be established (see Target Portal Group 1). In addition, this example shows the Initiator using a different Portal Group than the Target Portal Group, but the Initiator Portal group sharing Network Portal A with the Target Portal Group. ----------------------------IP Network--------------------- | | | +----|---------------|------+ +-----|-----------+ | +----------+ +----------+ | | +----------+ | | | Network | | Network | | | | Network | | | | Portal A | | Portal B | | | | Portal A | | | +----------+ +----------+ | | +----------+ | | | Target | | | | Initiator | | | Portal | | | | Portal | | | Group 1 | | | | Group 2 | +----|---------------|------+ +-----|-----------+ | | | +----------|---------------|--------------------|--------------------+ | +--------|---------------|----+ +-------------|------------------+ | | |+-------|---------------|---+| |+------------|-----------------+| | | ||iSCSI Session (Target side)|| ||iSCSI Session (Initiator side)|| | | || || || || | | || (TSIH = 56) || || (SSID = 48) || | | |+---------------------------+| |+------------------------------+| | | | | | | | | | iSCSI Target Node | | iSCSI Initiator Node | | | +-----------------------------+ +--------------------------------+ | | iSCSI Node | | (within Network Entity, not shown) | +--------------------------------------------------------------------+ Knight, et al. Expires June 10, 2010 Page 12 Internet-Draft iSCSI Update December 09 6 Negotiation of New Feature Use The PDUFormatForSAMUpdate operational text key (see 9.1.1) containing a value of "Yes" MUST be negotiated to enable the use of features described in this RFC. 7 SCSI Commands 7.1 SCSI Command Additions The format of the SCSI Command PDU is: Byte/ 0 | 1 | 2 | 3 | / | | | | |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| +---------------+---------------+---------------+---------------+ 0|.|I| 0x01 |F|R|W|. .|ATTR | PRI | Reserved | +---------------+---------------+---------------+---------------+ 4|TotalAHSLength | DataSegmentLength | +---------------+---------------+---------------+---------------+ 8| Logical Unit Number (LUN) | + + 12| | +---------------+---------------+---------------+---------------+ 16| Initiator Task Tag | +---------------+---------------+---------------+---------------+ 20| Expected Data Transfer Length | +---------------+---------------+---------------+---------------+ 24| CmdSN | +---------------+---------------+---------------+---------------+ 28| ExpStatSN | +---------------+---------------+---------------+---------------+ 32/ SCSI Command Descriptor Block (CDB) / +/ / +---------------+---------------+---------------+---------------+ 48/ AHS (Optional) / +---------------+---------------+---------------+---------------+ x/ Header Digest (Optional) / +---------------+---------------+---------------+---------------+ y/ (DataSegment, Command Data) (Optional) / +/ / +---------------+---------------+---------------+---------------+ z/ Data Digest (Optional) / +---------------+---------------+---------------+---------------+ 7.1.1 Command Priority (byte 2) Knight, et al. Expires June 10, 2010 Page 13 Internet-Draft iSCSI Update December 09 The Command Priority (PRI) specifies the relative scheduling importance of this task in relation to other SIMPLE tasks already in the task set (see [SAM4]). As defined in Section 10, iSCSI PDU Formats of [RFC3720], compliant senders already set this field to zero. A sender MUST NOT set this field to a value other than zero unless the PDUFormatForSAMUpdate text key defined in section 9.1.1 has been negotiated on the session with a value of "Yes". This field MUST be ignored by iSCSI targets unless the PDUFormatForSAMUpdate text key with a value of "Yes" as defined in section 9.1.1 was negotiated on the session. Knight, et al. Expires June 10, 2010 Page 14 Internet-Draft iSCSI Update December 09 7.2 SCSI Response Additions The format of the SCSI Response PDU is: Byte/ 0 | 1 | 2 | 3 | / | | | | |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| +---------------+---------------+---------------+---------------+ 0|.|.| 0x21 |1|. .|o|u|O|U|.| Response | Status | +---------------+---------------+---------------+---------------+ 4|TotalAHSLength | DataSegmentLength | +---------------+---------------+---------------+---------------+ 8| Status Qualifier | Reserved | +---------------+---------------+---------------+---------------+ 12| Reserved | +---------------+---------------+---------------+---------------+ 16| Initiator Task Tag | +---------------+---------------+---------------+---------------+ 20| SNACK Tag or Reserved | +---------------+---------------+---------------+---------------+ 24| StatSN | +---------------+---------------+---------------+---------------+ 28| ExpCmdSN | +---------------+---------------+---------------+---------------+ 32| MaxCmdSN | +---------------+---------------+---------------+---------------+ 36| ExpDataSN or Reserved | +---------------+---------------+---------------+---------------+ 40| Bidirectional Read Residual Count or Reserved | +---------------+---------------+---------------+---------------+ 44| Residual Count or Reserved | +---------------+---------------+---------------+---------------+ 48| Header-Digest (Optional) | +---------------+---------------+---------------+---------------+ / Data Segment (Optional) / +/ / +---------------+---------------+---------------+---------------+ | Data-Digest (Optional) | +---------------+---------------+---------------+---------------+ 7.2.1 Status Qualifier The Status Qualifier provides additional status information (see [SAM4]). As defined in Section 10, iSCSI PDU Formats of [RFC3720], compliant senders already set this field to zero. Compliant senders MUST NOT set this field to a value other than zero unless Knight, et al. Expires June 10, 2010 Page 15 Internet-Draft iSCSI Update December 09 the PDUFormatForSAMUpdate text key with a value of "Yes" as defined in section 9.1.1 was negotiated on the session. This field MUST be ignored by receivers unless the PDUFormatForSAMUpdate text key with a value of "Yes" as defined in section 9.1.1 was negotiated on the session. 7.2.2 Data Segment - Sense and Response Data Segment Section 10.4.7 of [RFC3720] specifies that iSCSI targets MUST support and enable autosense. If Status is CHECK CONDITION (0x02), then the Data Segment MUST contain sense data for the failed command. While [RFC3720] does not make any statements about the state of the Data Segment when the Status is not CHECK CONDITION (0x02)(i.e., the Data Segment is not prohibited from containing sense data when the Status is not CHECK CONDITION), negotiation of the PDUFormatForSAMUpdate text key with a value of "Yes" as defined in section 9.1.1 explicitly indicates that the Data Segment MAY contain sense data at any time, no matter what value is set in the Status field. 8 Task Management Functions 8.1 Existing Task Management Functions Section 10.5 of [RFC3720] defines the semantics used to request SCSI Task Management Functions be performed. The following task management functions are defined: 1 - ABORT TASK 2 - ABORT TASK SET 3 - CLEAR ACA 4 - CLEAR TASK SET 5 - LOGICAL UNIT RESET 6 - TARGET WARM RESET 7 - TARGET COLD RESET 8 - TASK REASSIGN 8.2 Task Management Function Additions Additional task Management function codes are listed below. For a more detailed description of SCSI task management, see [SAM5]. 9 - QUERY TASK - determines if the task identified by the Referenced Task Tag field is present in the task set. 10 - QUERY TASK SET - determine if any task is present in the task set. Knight, et al. Expires June 10, 2010 Page 16 Internet-Draft iSCSI Update December 09 11 - I_T NEXUS RESET - perform an I_T nexus loss function for the I_T nexus of each logical unit accessible through the I_T Nexus on which the task management function was received. 12 - QUERY ASYNCHRONOUS EVENT - determine if there is a unit attention condition or a deferred error pending for the I_T nexus on which the task management function was received. Any compliant sender MUST NOT send these task management function requests unless the PDUFormatForSAMUpdate text key with a value of "Yes" as defined in section 9.1.1 was negotiated on the session. Any compliant initiator that sends any of the new task management functions defined in this section MUST also support all new task management function responses (see 8.3.1). For all of the task management functions detailed in this section, the Task Management function response MUST be returned as detailed in section 8.3 Task Management Function Response. The iSCSI target MUST ensure that no responses for the tasks covered by a task management function are delivered to the iSCSI initiator after the Task Management response except for a task covered by a TASK REASSIGN, QUERY TASK, or QUERY TASK SET. If a QUERY TASK is issued for a task created by an immediate command then RefCmdSN MUST be that of the Task Management request itself (i.e., CmdSN and RefCmdSN are equal); otherwise RefCmdSN MUST be set to the CmdSN of the task to be queried (lower than CmdSN). At the target a QUERY TASK function MUST NOT be executed on a Task Management request; such a request MUST result in Task Management response of "Function rejected". For the I_T NEXUS RESET function, the target device MUST respond to the function as defined in [SAM4]. Each logical unit accessible via the receiving I_T NEXUS MUST behave as dictated by the I_T nexus loss function in [SAM4] for the I_T nexus on which the task management function was received. The target device MUST drop all connections in the session over which this function is recevied. Independent of the DefaultTime2Wait and DefaultTime2Retain value applicable to the session over which this function is received, the target device MUST consider each participating connection in the session to have immediately timed out, leading to FREE state. The resulting timeouts cause the session timeout event defined in [RFC3720], which in turn triggers the I_T nexus loss notification to the SCSI layer as described in [RFC3720]. Knight, et al. Expires June 10, 2010 Page 17 Internet-Draft iSCSI Update December 09 8.2.1 LUN field This field is required for functions that address a specific LU (ABORT TASK, CLEAR TASK SET, ABORT TASK SET, CLEAR ACA, LOGICAL UNIT RESET, QUERY TASK, QUERY TASK SET, I_T NEXUS RESET, and QUERY ASYNCHRONOUS EVENT) and is reserved in all others. 8.2.2 Referenced Task Tag The Initiator Task Tag of the task to be aborted for the ABORT TASK function, reassigned for the TASK REASSIGN function, or queried for the QUERY TASK function. For all other functions this field MUST be set to the reserved value 0xffffffff. 8.2.3 RefCmdSN If a QUERY TASK is issued for a task created by an immediate command then RefCmdSN MUST be that of the Task Management request itself (i.e., CmdSN and RefCmdSN are equal). For a QUERY TASK of a task created by non-immediate command RefCmdSN MUST be set to the CmdSN of the task identified by the Referenced Task Tag field. Targets must use this field as described in section 10.6.1 of [RFC3720] when the task identified by the Referenced Task Tag field is not in the task set. Knight, et al. Expires June 10, 2010 Page 18 Internet-Draft iSCSI Update December 09 8.3 Task Management Function Responses Byte/ 0 | 1 | 2 | 3 | / | | | | |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| +---------------+---------------+---------------+---------------+ 0|.|.| 0x22 |1| Reserved | Response | Reserved | +---------------+---------------+---------------+---------------+ 4|TotalAHSLength | DataSegmentLength | +-----------------------------------------------+---------------+ 8| Additional Response Information | Reserved | +-----------------------------------------------+---------------+ 12| Reserved | +---------------+---------------+---------------+---------------+ 16| Initiator Task Tag | +---------------+---------------+---------------+---------------+ 20| Reserved | +---------------+---------------+---------------+---------------+ 24| StatSN | +---------------+---------------+---------------+---------------+ 28| ExpCmdSN | +---------------+---------------+---------------+---------------+ 32| MaxCmdSN | +---------------+---------------+---------------+---------------+ 36/ Reserved / +/ / +---------------+---------------+---------------+---------------+ 48| Header-Digest (Optional) | +---------------+---------------+---------------+---------------+ Section 10.6 of [RFC3720] defines the semantics used for responses to SCSI Task Management Functions. The following responses are defined in [RFC3720]: 0 - Function Complete. 1 - Task does not exist. 2 - LUN does not exist. 3 - Task still allegiant. 4 - Task allegiance reassignment not supported. 5 - Task management function not supported. 6 - Function authorization failed. 255 - Function rejected. Responses to new task management functions (see 8.3.1) are listed below. In addition, a new task Management response is listed below. For a more detailed description of SCSI task management responses, see [SAM5]. Knight, et al. Expires June 10, 2010 Page 19 Internet-Draft iSCSI Update December 09 For the functions QUERY TASK, QUERY TASK SET, I_T NEXUS RESET, and QUERY ASYNCHRONOUS EVENT, the target performs the requested Task Management function and sends a Task Management response back to the initiator. 8.3.1 Task Management Function Response Additions The new response is listed below: 7 - Function succeeded. In symbolic terms Response value 7 maps to the SCSI service response of FUNCTION SUCCEEDED. The task management function response of function succeeded MUST be supported by an initiator that sends any of the new task management functions (see 8.2). For the QUERY TASK function, if the specified task is in the task set, then the target returns a Response value of Function succeeded and additional response information is returned as specified in [SAM5]. If the specified task is not in the task set, then the target returns a Response value of Function complete. For the QUERY TASK SET function, if there is any command present in the task set from the specified I_T_L nexus, then the target returns a Response value of Function succeeded. If there are no commands present in the task set from the specified I_T_L nexus, then the target returns a Response value of Function complete. For the I_T NEXUS RESET function, after completion of the events described in section 8.2 for this function, the target returns a Response value of Function complete. However, because the target drops all connections, the Service Response (defined by [SAM2]) for this SCSI task management function may not be reliably delivered to the issuing initiator port. For the QUERY ASYNCHRONOUS EVENT, if there is a unit attention condition or deferred error pending for the specified I_T nexus, then the target returns a Response value of Function succeeded and additional response information is returned as specified in [SAM5]. If there is no unit attention or deferred error pending for the specified I_T nexus then the target returns a Response value of Function complete. 8.4 Task Management Requests Affecting Multiple Tasks Section 4.1 of [RFC5048] defines the notion of "affected tasks" in multi-task abort scenarios. This section adds to the list Knight, et al. Expires June 10, 2010 Page 20 Internet-Draft iSCSI Update December 09 include in that section by defining the tasks affected by the I_T NEXUS RESET function. I_T NEXUS RESET: All outstanding tasks received on the I_T nexus on which the function request was received for all logical units accessible to the I_T nexus. Section 4.1.2 of [RFC5048] and section 4.1.3 of [RFC5048] identify semantics for task management functions that involve multi-task abort operations. If an iSCSI implementation supports the I_T NEXUS RESET function, it MUST also support the protocol behavior as defined in those sections and follow the sequence of actions as described in those sections when processing the I_T NEXUS RESET function. 9 Login/Text Operational Text Keys 9.1 New Operational Text Keys 9.1.1 PDUFormatForSAMUpdate Use: LO Irrelevant when: SessionType = Discovery Senders: Initiator and Target Scope: SW PDUFormatForSAMUpdate= Default is No. Result function is AND. This key is used to negotiate the RFC compliance level applicable to the iSCSI session once the session is in full feature phase. If the negotiation answer is ignored by the acceptor, or the answer from the remote iSCSI end point is key=NotUnderstood, then the features defined in this RFC MUST NOT be used. Note that operational value of "Yes" for this key on an iSCSI session does not influence the SCSI level features in any way on that I_T nexus. An operational value of "Yes" for this key permits the iSCSI-related features defined in this document to be used on all connections on this iSCSI session. SCSI level hand- shakes (e.g. commands, mode pages) eventually determine the existence or lack of various SAM features available for the I_T nexus between the two SCSI end points). To summarize, negotiation of this key to "Yes" is a necessary but not a sufficient condition of SAM-4 compliant feature usage at the SCSI protocol level. Knight, et al. Expires June 10, 2010 Page 21 Internet-Draft iSCSI Update December 09 10 Security Considerations At the time of writing this document does not introduce any new security considerations other than those described in [RFC3720]. Consequently, all the iSCSI-related security text in [RFC3723] is also directly applicable to this document. 11 IANA Considerations This document modifies or creates a number of iSCSI-related registries. The following iSCSI-related registries are modified: 1. iSCSI Task Management Functions Codes Name of the existing registry: "iSCSI TMF Codes" Additional entries: 9, QUERY TASK, [RFCxxx] 10, QUERY TASK SET, [RFCxxx] 11, I_T NEXUS RESET, [RFCxxx] 12, QUERY ASYNCHRONOUS EVENT, [RFCxxx] --------------------------------------------------------- RFC EDITORS NOTE: The above reference to [RFCxxx] should reference this RFC, and this note should be removed. --------------------------------------------------------- 2. iSCSI Login/Text Keys Name of the existing registry: "iSCSI Text Keys" Additional entry: PDUFormatForSAMUpdate, [RFCxxx] --------------------------------------------------------- RFC EDITORS NOTE: The above reference to [RFCxxx] should reference this RFC, and this note should be removed. --------------------------------------------------------- This document creates the following iSCSI-related registries for IANA to manage. 3. iSCSI Task Management Response Codes Name of new registry: "iSCSI TMF Response Codes" Knight, et al. Expires June 10, 2010 Page 22 Internet-Draft iSCSI Update December 09 Namespace details: Numerical values that can fit in 8 bits. Information that must be provided to assign a new value: An IESG-approved specification defining the semantics and interoperability requirements of the proposed new value and the fields to be recorded in the registry. Assignment policy: If the requested value is not already assigned, it may be assigned to the requester. 8-254: Range reserved by iANA for assignment in this registry. Fields to record in the registry: Assigned value, Operation Name, and its associated RFC reference. 0x0, Function complete, [RFC3720] 0x1, Task does not exist, [RFC3720] 0x2, LUN does not exist, [RFC3720] 0x3, Task still allegiant, [RFC3720] 0x4, Task allegiance reassignment not supported, [RFC3720] 0x5, Task management function not supported, [RFC3720] 0x6, Function authorization failed, [RFC3720] 0x7, Function succeeded, [RFCxxx] 255, Function rejected, [RFC3720] ------------------------------------------------------------ RFC EDITORS NOTE: The above reference to [RFCxxx] should reference this RFC, and this note should be removed. ------------------------------------------------------------ Allocation Policy: Standards Action ([IANA]) 12 References 12.1 Normative References Knight, et al. Expires June 10, 2010 Page 23 Internet-Draft iSCSI Update December 09 [RFC2119] Bradner, S. "Key Words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC3720] Satran, J., Meth, K., Sapuntzakis, C., Chadalapaka, M., and E. Zeidner, "Internet Small Computer Systems Interface (iSCSI)", RFC 3720, April 2004. [RFC3723] Aboba, B., Tseng, J., Walker, J., Rangan, V., and Travostino, F., "Securing Block Storage Protocols over IP", RFC 3723, April 2004. [RFC5048] Chadalapaka, M., "Internet Small Computer System Interface (iSCSI) Corrections and Clarifications", RFC 5048, October 2007. [IANA] Narten, T. and H. Alvestrand, "Guidelines for Writing an IANA Considerations Section in RFCs", BCP 26, RFC 5226, May 2008. [UML] ISO/IEC 19501, Unified Modeling Language Specification Version 1.4.2. [SAM2] T10/1157D, SCSI Architecture Model - 2 (SAM-2). [SAM4] ISO/IEC 14776-414, SCSI Architecture Model - 4 (SAM- 4). 12.2 Informative References [SAM5] T10/2104D rev xxx, SCSI Architecture Model - 5 (SAM- 5), Work in Progress. 12.3 Additional Reference Sources For more information on the SCSI Architecture Model, contact the T10 group at http://www.t10.org. For more information on the UML specification, contact the Object Modeling Group at http://www.omg.org. 13 Acknowledgements The Storage Maintenance (STORM) Working Group in the Transport Area of the IETF has been responsible for defining these additions to the iSCSI protocol (apart from other relevant IP Storage protocols). The editor acknowledges the contributions of the entire working group. Knight, et al. Expires June 10, 2010 Page 24 Internet-Draft iSCSI Update December 09 The following individuals directly contributed to identifying [RFCxxx] issues and/or suggesting resolutions to the issues clarified in this document: Mallikarjun Chadalapaka, David Black, Rob Elliott. This document benefited from all of these contributions. ------------------------------------------------------------ RFC EDITORS NOTE: The above reference to [RFCxxx] should reference this RFC, and this note should be removed. ------------------------------------------------------------ Editor's Address Frederick Knight 7301 Kit Creek Road P.O. Box 13917 Research Triangle Park, NC 27709 Phone: +1-919-476-5362 Email: knight@netapp.com Knight, et al. Expires June 10, 2010 Page 25