Sieve WG R. Mahy Internet-Draft Plantronics Expires: January 2, 2008 July 1, 2007 Sieve Notification Using the Session Initiation Protocol (SIP) Message Summary and Message Waiting Indication Event Package draft-mahy-sieve-notify-sip-00.txt Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. 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/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on January 2, 2008. Copyright Notice Copyright (C) The IETF Trust (2007). Abstract This document describes using the existing SIP message-summary event package to carry notifications generated from Sieve filter rules. Mahy Expires January 2, 2008 [Page 1] Internet-Draft Sieve Notification using SIP July 2007 Table of Contents 1. Conventions . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Background . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Use of Sieve filters in a message-summary subscription . . . . 4 4. New MIME Type for notification bodies . . . . . . . . . . . . 5 5. Example Message Flow . . . . . . . . . . . . . . . . . . . . . 5 6. Formal Syntax . . . . . . . . . . . . . . . . . . . . . . . . 11 7. Security Considerations . . . . . . . . . . . . . . . . . . . 11 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11 8.1. MIME Registration for application/sieve-notification+xml . . . . . . . . . . . . 12 9. Relax NG Schema . . . . . . . . . . . . . . . . . . . . . . . 13 10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13 10.1. Normative References . . . . . . . . . . . . . . . . . . . 13 10.2. Informational References . . . . . . . . . . . . . . . . . 14 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 14 Intellectual Property and Copyright Statements . . . . . . . . . . 15 Mahy Expires January 2, 2008 [Page 2] Internet-Draft Sieve Notification using SIP July 2007 1. Conventions 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 RFC-2119 [5]. 2. Background Sieve [1] is an email filtering language. Individual rules in this language check for specific conditions, and then execute specific actions. One supported action sends a Sieve notification [2], for example using email [9] or XMPP [10] (Extensible Messaging and Presence Protocol). SIP [3] is a protocol used for rendezvous, management of multimedia sessions, and relevant event notifications [4]. Messaging Waiting Indication is a common feature of telephone networks. It typically involves an audible or visible indication that messages are waiting, such as playing a special dial tone, lighting a light or indicator on the phone, displaying icons or text, or some combination. RFC 3842 [7] defines a SIP event package to alert the subscriber when the types of messages available have changed. Using SIP-Specific Event Notification, A Subscriber User Agent (typically an IP phone or SIP software User Agent) subscribes to the status of their messages. A SIP User Agent acting on behalf of the user's messaging system then notifies the Subscriber whenever the messaging account's messages have changed. (This Notifier could be composed with a User Agent that provides a real-time media interface to send or receive messages, or it could be a standalone entitiy.) The Notifier sends a message summary in the body of a NOTIFY, encoded in a new MIME type defined later in this document. A User Agent can also explicitly fetch the current status. This document describes how to use the existing SIP message-summary event package to convey only notifications specified by the Sieve filtering language. Sieve notifications in the context of this event package are always explicitly authorized. This avoids delivering notifications about possibly unwanted unsolicited events. The Email System Event Notification Model [12] describes sending notifications about several kinds of events which are relevant to email systems [11], and describes a model to convey those notifications. This document is largely orthogonal in that it provides access to almost none of the mailbox events, and it explicitly defines a mechanism to dynamically setup a sieve filter and solicit notifications indirectly triggered by new incoming Mahy Expires January 2, 2008 [Page 3] Internet-Draft Sieve Notification using SIP July 2007 messages (which the model does not address). The notifier for this package could be collocated with the "Publisher Notifications Aggregator (PNA)" role described in the model document. 3. Use of Sieve filters in a message-summary subscription SIP event notification is designed to present consistent, reliable, synchronized state even when SIP user agents temporarily lose and re- establish network connectivity. Because of this design requirement, a new subscription always contains an explicit initial state. In the context of Sieve notifications, this initial state can contain notifications that the subscriber has not seen yet, even if those notifications where already sent using other notification methods or received by other SIP subscribers. Since multiple Sieve notifications could be received in a single NOTIFY request, the notifications are enclosed in a simple container using XML, as described in the next section. To explicitly indicate the begining of time to use for notifications, the subscriber can include a new optional SIP Event header parameter 'notify-counter'. If this parameter is included, the notifier can provide notifications consistent with this "version" of the notify- counter. If the notification contains the same notify-counter as the corresponding subscription, the subscriber knows that it did not miss any notifications. When a MIME body is included in a SIP SUBSCRIBE request, this body is treated as an event filter. In this application, the filter is an "application/sieve" document, with a few specific requirements described below. The filter document used for filtering SHOULD NOT include Actions other than "notify", for example: keep, delete, or fileto. The Sieve notify tag ":method" MUST NOT be included, and MUST be ignored if it present. The notification method and URI are already specified more formally in the SIP SUBSCRIBE request. Likewise the notify tag ":from" MUST be ignored. The From header of the notification is already set in the SIP dialog used for the subscription. The ":message" notify tag is used to construct a (probably human- readable) string that appears in the 'message' element of the notification. This document also defines a new notify option "headerlist" (used with the ":options" notify tag). The value of the "headerlist" option is a comma-separated list of email headers, each of which will be included in its own 'header' element in the notification. The usage of the headerlist is completely optional. Mahy Expires January 2, 2008 [Page 4] Internet-Draft Sieve Notification using SIP July 2007 4. New MIME Type for notification bodies This section defines a new MIME type "application/ sieve-notification+xml". This document format contains a top-level 'sieve-notifications' element, which has a mandatory 'notify-counter' attribute. This counter is an unsigned integer. This element contains zero or more 'notification' elements. Each 'notification' element contains exactly one 'message' element with the populated contents of the ":message" notify tag. Each 'notification' element can also contain zero or more 'header' elements. Each 'header' element has a mandatory 'name' attribute with the name of a header from the 'headerlist' ":options" notify tag. The contents of the 'header' element is the value of the named header. A relax NG schema for this body type is included in the Appendix. Below is a Sieve filter in a SUBSCRIBE body, and the corresponding notification body. A full example is given in the next section. === SUBSCRIBE Body === require ["enotify"]; if header :contains "from" "example.com" { notify :message "Reminder to call about project foobar" :options "headerlist" "From,Subject"; } === NOTIFY Body ===
alice@example.com
Foobar status report
Reminder to call about project foobar 5. Example Message Flow The examples shown below are for informational purposes only. In the example call flow below, Alice's IP phone subscribes to the status of Alice's messages. Via headers are omitted for clarity. Subscriber Notifier | | | A1: SUBSCRIBE (new) | |---------------------->| Mahy Expires January 2, 2008 [Page 5] Internet-Draft Sieve Notification using SIP July 2007 | A2: 200 OK | |<----------------------| | | | A3: NOTIFY (sync) | |<----------------------| | A4: 200 OK | |---------------------->| | | | |<--- email arrives | A5: NOTIFY (change) | |<----------------------| | A6: 200 OK | |---------------------->| | | | | | A7: (re)SUBSCRIBE | |---------------------->| | A8: 200 OK | |<----------------------| | | | A9: NOTIFY (sync) | |<----------------------| | A10: 200 OK | |---------------------->| | | | | | A11: (un)SUBSCRIBE | |---------------------->| | A12: 200 OK | |<----------------------| | | | A13: NOTIFY (sync) | |<----------------------| | A14: 200 OK | |---------------------->| A1: Subscriber (Alice's phone) -> Notifier (Alice's voicemail gateway) Subscribe to Alice's message summary status for 1 hour. SUBSCRIBE sip:alice@vmail.example.com SIP/2.0 To: From: ;tag=78923 Date: Mon, 10 Jul 2000 03:55:06 GMT Call-Id: 1349882@alice-phone.example.com CSeq: 4 SUBSCRIBE Contact: Mahy Expires January 2, 2008 [Page 6] Internet-Draft Sieve Notification using SIP July 2007 Event: message-summary Expires: 3600 Accept: application/sieve-notification+xml Content-Type: application/sieve Content-Length: 85 require ["enotify"]; if header :contains "from" "example.com" { notify :message "Reminder to call about project foobar" :options "headerlist" "From,Subject"; } A2: Notifier -> Subscriber SIP/2.0 200 OK To: ;tag=4442 From: ;tag=78923 Date: Mon, 10 Jul 2000 03:55:07 GMT Call-Id: 1349882@alice-phone.example.com CSeq: 4 SUBSCRIBE Expires: 86400 Content-Length: 0 A3: Notifier -> Subscriber (immediate synchronization of current state: no notifications to report) NOTIFY sip:alice@alice-phone.example.com SIP/2.0 To: ;tag=78923 From: ;tag=4442 Date: Mon, 10 Jul 2000 03:55:07 GMT Call-Id: 1349882@alice-phone.example.com CSeq: 20 NOTIFY Contact: Event: message-summary Subscription-State: active;expires=3600 Content-Type: application/sieve-notification+xml Content-Length: 79 A4: Subscriber -> Notifier SIP/2.0 200 OK Mahy Expires January 2, 2008 [Page 7] Internet-Draft Sieve Notification using SIP July 2007 To: ;tag=78923 From: ;tag=4442 Date: Mon, 10 Jul 2000 03:55:08 GMT Call-Id: 1349882@alice-phone.example.com CSeq: 20 NOTIFY Content-Length: 0 A5: Notifier -> Subscriber This is a notification of a new message. NOTIFY sip:alice@alice-phone.example.com SIP/2.0 To: ;tag=78923 From: ;tag=4442 Date: Mon, 10 Jul 2000 04:28:53 GMT Contact: Call-ID: 1349882@alice-phone.example.com CSeq: 31 NOTIFY Event: message-summary Subscription-State: active;expires=1665 Content-Type: application/sieve-notification+xml Content-Length:
alice@example.com
Foobar status report
Reminder to call about project foobar A6: Subscriber -> Notifier SIP/2.0 200 OK To: ;tag=78923 From: ;tag=4442 Date: Mon, 10 Jul 2000 04:28:53 GMT Call-ID: 1349882@alice-phone.example.com CSeq: 31 NOTIFY Content-Length: 0 A7: Subscriber -> Notifier Refresh subscription. SUBSCRIBE sip:alice@vmail.example.com SIP/2.0 To: ;tag=4442 Mahy Expires January 2, 2008 [Page 8] Internet-Draft Sieve Notification using SIP July 2007 From: ;tag=78923 Date: Mon, 10 Jul 2000 04:55:06 GMT Call-Id: 1349882@alice-phone.example.com CSeq: 8 SUBSCRIBE Contact: Event: message-summary;notify-counter=4589 Expires: 3600 Accept: application/sieve-notification+xml Content-Length: 0 A8: Notifier -> Subscriber SIP/2.0 200 OK To: ;tag=4442 From: ;tag=78923 Date: Mon, 10 Jul 2000 04:55:07 GMT Call-Id: 1349882@alice-phone.example.com CSeq: 8 SUBSCRIBE Contact: Expires: 86400 Content-Length: 0 A9: Notifier -> Subscriber (immediate synchronization of current state) NOTIFY sip:alice@alice-phone.example.com SIP/2.0 To: ;tag=78923 From: ;tag=4442 Date: Mon, 10 Jul 2000 04:55:07 GMT Call-Id: 1349882@alice-phone.example.com CSeq: 47 NOTIFY Contact: Event: message-summary Subscription-State: active;expires=3600 Content-Type: application/sieve-notification+xml Content-Length: 79 A10: Subscriber -> Notifier SIP/2.0 200 OK To: ;tag=78923 From: ;tag=4442 Date: Mon, 10 Jul 2000 04:55:08 GMT Call-Id: 1349882@alice-phone.example.com CSeq: 47 NOTIFY Mahy Expires January 2, 2008 [Page 9] Internet-Draft Sieve Notification using SIP July 2007 Contact: A11: Subscriber -> Notifier Un-subscribe after "alice" logs out. SUBSCRIBE sip:alice@vmail.example.com SIP/2.0 To: ;tag=4442 From: ;tag=78923 Date: Mon, 10 Jul 2000 05:35:06 GMT Call-Id: 1349882@alice-phone.example.com CSeq: 17 SUBSCRIBE Contact: Event: message-summary Expires: 0 Content-Length: 0 A12: Notifier -> Subscriber SIP/2.0 200 OK To: ;tag=4442 From: ;tag=78923 Date: Mon, 10 Jul 2000 05:35:07 GMT Call-Id: 1349882@alice-phone.example.com CSeq: 17 SUBSCRIBE Contact: Content-Length: 0 A13: Notifier -> Subscriber (immediate synchronization of current state, which the subscriber can now ignore) NOTIFY sip:alice@alice-phone.example.com SIP/2.0 To: ;tag=78923 From: ;tag=4442 Date: Mon, 10 Jul 2000 05:35:07 GMT Call-Id: 1349882@alice-phone.example.com CSeq: 56 NOTIFY Contact: Event: message-summary Subscription-State: terminated;reason=timeout Content-Type: application/sieve-notification+xml Content-Length: 79 A14: Subscriber -> Notifier Mahy Expires January 2, 2008 [Page 10] Internet-Draft Sieve Notification using SIP July 2007 SIP/2.0 200 OK To: ;tag=78923 From: ;tag=4442 Date: Mon, 10 Jul 2000 05:35:08 GMT Call-Id: 1349882@alice-phone.example.com CSeq: 56 NOTIFY Event: message-summary Content-Length: 0 6. Formal Syntax The following syntax specification uses the augmented Backus-Naur Form (BNF) as described in RFC 4234 [6]. This document defines a new Event header parameter with the name 'notify-counter'. Its formal syntax is described below: notify-counter = "notify-counter" EQUAL 1*DIGIT ; MUST NOT exceed 2^32-1 7. Security Considerations The bulk of the relevant privacy and security considerations are discussed in Sieve [1] and Sieve notifications [2]. In addition, SIP [3] subscriptions SHOULD be authenticated and authorized to fetch notifications for the target SIP resource / mailbox. (Digest authentication is mandatory to implement in all SIP nodes.) In addition, the SIP Identity header [8] can be used to insure that notifications were not forged and were not modified in transit. To prevent eavesdropping, the SIP subscriber could insist on using the sips: scheme which insures that SIP messages are only sent over TLS protected channels. Finally, a truly paranoid user can use the SIP S/MIME mechanism for end-to-end encryption, authentication, and message integrity. 8. IANA Considerations Mahy Expires January 2, 2008 [Page 11] Internet-Draft Sieve Notification using SIP July 2007 8.1. MIME Registration for application/sieve-notification+xml MIME media type name: application MIME subtype name: sieve-notification+xml Required parameters: none. Optional parameters: none. Encoding considerations: Usual XML stuff here. Security considerations: See the "Security Considerations" section in this document. Interoperability considerations: none Published specification: This document. Applications which use this media: The sieve-notification application subtype supports the exchange of sieve email notification information in SIP networks. Additional information: 1. Magic number(s): N/A 2. File extension(s): N/A 3. Macintosh file type code: N/A Mahy Expires January 2, 2008 [Page 12] Internet-Draft Sieve Notification using SIP July 2007 9. Relax NG Schema 10. References 10.1. Normative References [1] Showalter, T. and P. Guenther, "Sieve: An Email Filtering Language", draft-ietf-sieve-3028bis-12 (work in progress), February 2007. [2] Melnikov, A., "Sieve Extension: Notifications", draft-ietf-sieve-notify-07 (work in progress), February 2007. [3] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A., Peterson, J., Sparks, R., Handley, M., and E. Schooler, "SIP: Session Initiation Protocol", RFC 3261, June 2002. [4] Roach, A., "Session Initiation Protocol (SIP)-Specific Event Notification", RFC 3265, June 2002. [5] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [6] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", RFC 4234, October 2005. [7] Mahy, R., "A Message Summary and Message Waiting Indication Event Package for the Session Initiation Protocol (SIP)", RFC 3842, August 2004. Mahy Expires January 2, 2008 [Page 13] Internet-Draft Sieve Notification using SIP July 2007 [8] Peterson, J. and C. Jennings, "Enhancements for Authenticated Identity Management in the Session Initiation Protocol (SIP)", RFC 4474, August 2006. 10.2. Informational References [9] Leiba, B. and M. Haardt, "Sieve Notification Mechanism: mailto", draft-ietf-sieve-notify-mailto-02 (work in progress), March 2007. [10] Saint-Andre, P. and A. Melnikov, "Sieve Notification Mechanism: xmpp", draft-ietf-sieve-notify-xmpp-04 (work in progress), March 2007. [11] Gellens, R. and C. Newman, "Internet Message Store Events", draft-ietf-lemonade-msgevent-02 (work in progress), May 2007. [12] Dusseault, L., "Email System Event Notification Model", draft-dusseault-email-notif-model-00 (work in progress), June 2007. Author's Address Rohan Mahy Plantronics 345 Encinal St Santa Cruz, CA 95060 USA Email: rohan@ekabal.com Mahy Expires January 2, 2008 [Page 14] Internet-Draft Sieve Notification using SIP July 2007 Full Copyright Statement Copyright (C) The IETF Trust (2007). This document is subject to the rights, licenses and restrictions contained in BCP 78, and except as set forth therein, the authors retain all their rights. This document and the information contained herein are provided on an "AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. 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The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights that may cover technology that may be required to implement this standard. Please address the information to the IETF at ietf-ipr@ietf.org. Acknowledgment Funding for the RFC Editor function is provided by the IETF Administrative Support Activity (IASA). Mahy Expires January 2, 2008 [Page 15]