Network Working Group A. Melnikov Internet-Draft Isode Ltd Updates: 3501, 4466, 7888 (if approved) SB. Jayantheesh Intended status: Standards Track Samsung Electronics America Expires: March 22, 2018 September 18, 2017 64bit body part and message sizes in IMAP4 draft-ietf-extra-imap-64bit-01.txt Abstract This document defines an IMAPv4rev1 extension that extends the existing IMAPv4rev1 32 Bit message and body part sizes to 63 bit. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. 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Melnikov & Jayantheesh Expires March 22, 2018 [Page 1] Internet-Draft 64bit body part and message sizes in IMAP4 September 2017 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. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Requirements Notation . . . . . . . . . . . . . . . . . . . . 2 3. 64bit Extension . . . . . . . . . . . . . . . . . . . . . . . 3 4. IMAP Protocol Changes . . . . . . . . . . . . . . . . . . . . 3 5. Examples . . . . . . . . . . . . . . . . . . . . . . . . . . 3 6. Formal Syntax . . . . . . . . . . . . . . . . . . . . . . . . 3 7. Security Considerations . . . . . . . . . . . . . . . . . . . 4 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 5 10. Normative References . . . . . . . . . . . . . . . . . . . . 5 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5 1. Introduction IMAP [RFC3501] only allows body parts or message sizes which are 32 bit. This document introduces an IMAP extension that allows for message and body part sizes to be 63 bit. The client wishing to use this extension MUST issue ENABLE 64BIT. Refer [RFC5161] for the usage of ENABLE command. 2. Requirements Notation 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]. In examples, "C:" and "S:" indicate lines sent by the client and server respectively. If a single "C:" or "S:" label applies to multiple lines, then the line breaks between those lines are for editorial clarity only and are not part of the actual protocol exchange. Melnikov & Jayantheesh Expires March 22, 2018 [Page 2] Internet-Draft 64bit body part and message sizes in IMAP4 September 2017 3. 64bit Extension An IMAP server that supports the 64bit extension advertises this by including the name 64BIT in its CAPABILITY list in the authenticated state. The server may also advertise this extension before the user has logged in. If this capability is omitted, no information is conveyed about the server's status of supporting this extension. IMAP server should respond with BAD response for the 64bit message size messages sent by the IMAP client unless it issues "ENABLE 64BIT" in the current connection. 4. IMAP Protocol Changes TBD. 5. Examples C: t1 CAPABILITY S: * CAPABILITY IMAP4rev1 ID 64BIT S: t1 OK foo C: t2 ENABLE 64BIT S: * ENABLED 64BIT S: t2 OK foo 6. Formal Syntax The following syntax specification uses the Augmented Backus-Naur Form (ABNF) notation as specified in [ABNF]. Non-terminals referenced but not defined below are as defined by [RFC3501]. All alphabetic characters are case-insensitive. The use of upper or lower case characters to define token strings is for editorial clarity only. Implementations MUST accept these strings in a case- insensitive fashion. Melnikov & Jayantheesh Expires March 22, 2018 [Page 3] Internet-Draft 64bit body part and message sizes in IMAP4 September 2017 body-extension =/ number64 ; Alexey: I am not sure if this change is absolutely needed! body-fld-lines = number64 body-fld-octets = number64 fetch-att =/ "BODY" section ["<" number64 "." nz-number64 ">"] / "BODY.PEEK" section ["<" number64 "." nz-number64 ">"] literal = "{" number64 ["+"] "}" CRLF *CHAR8 ; number64 represents the number of CHAR8s. ; NOTE: "+" can only present when LITERAL+/LITERAL- ; is also advertised literal8 = "~{" number64 ["+"] "}" CRLF *OCTET ;; Updating RFC 4466 version. ;; A string that might contain NULs. ;; represents the number of OCTETs ;; in the response string. ;; The "+" is only allowed when both LITERAL+/LITERAL- ;; and BINARY extensions are supported by the server ;; [RFC7888] msg-att-static =/ "RFC822.SIZE" SP number64 search-key =/ "LARGER" SP number64 / "SMALLER" SP number64 number64 = 1*DIGIT ; Unsigned 63-bit integer ; (0 <= n <= 9,223,372,036,854,775,807) nz-number64 = digit-nz *DIGIT ; Unsigned 63-bit integer ; (0 < n <= 9,223,372,036,854,775,807) CHAR8 = 7. Security Considerations TBD. This document doesn't raise any other security concerns not already raised by [RFC3501]. Melnikov & Jayantheesh Expires March 22, 2018 [Page 4] Internet-Draft 64bit body part and message sizes in IMAP4 September 2017 8. IANA Considerations IANA is asked to add "64BIT" to the IMAP Capabilities registry, using this document as its reference. 9. Acknowledgments TBD. 10. Normative References [ABNF] Crocker, D. and P. Overell, "Augmented BNF for Syntax Specifications: ABNF", STD 68, RFC 5234, January 2008. [RFC2088] Myers, J., "IMAP4 non-synchronizing literals", RFC 2088, DOI 10.17487/RFC2088, January 1997, . [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC3501] Crispin, M., "INTERNET MESSAGE ACCESS PROTOCOL - VERSION 4rev1", RFC 3501, DOI 10.17487/RFC3501, March 2003, . [RFC3516] Nerenberg, L., "IMAP4 Binary Content Extension", RFC 3516, DOI 10.17487/RFC3516, April 2003, . [RFC4466] Melnikov, A. and C. Daboo, "Collected Extensions to IMAP4 ABNF", RFC 4466, DOI 10.17487/RFC4466, April 2006, . [RFC5161] Gulbrandsen, A., Ed. and A. Melnikov, Ed., "The IMAP ENABLE Extension", RFC 5161, DOI 10.17487/RFC5161, March 2008, . Authors' Addresses Alexey Melnikov Isode Ltd 14 Castle Mews Hampton, Middlesex TW12 2NP UK Email: Alexey.Melnikov@isode.com Melnikov & Jayantheesh Expires March 22, 2018 [Page 5] Internet-Draft 64bit body part and message sizes in IMAP4 September 2017 Jayantheesh S B Samsung Electronics America 685 US Highway 202/206 Bridgewater, New Jersey 08807 USA Email: jayantheesh.sb@gmail.com Melnikov & Jayantheesh Expires March 22, 2018 [Page 6]