< draft-ietf-extra-quota-06.txt   draft-ietf-extra-quota-10.txt >
Network Working Group A. Melnikov Network Working Group A. Melnikov
Internet-Draft Isode Internet-Draft Isode
Obsoletes: 2087 (if approved) 27 August 2021 Obsoletes: 2087 (if approved) 18 November 2021
Intended status: Standards Track Intended status: Standards Track
Expires: 28 February 2022 Expires: 22 May 2022
IMAP QUOTA Extension IMAP QUOTA Extension
draft-ietf-extra-quota-06 draft-ietf-extra-quota-10
Abstract Abstract
The QUOTA extension of the Internet Message Access Protocol (RFC This document defines a QUOTA extension of the Internet Message
3501/RFC 9051) permits administrative limits on resource usage Access Protocol (RFC 3501/RFC 9051) that permits administrative
(quotas) to be manipulated through the IMAP protocol. limits on resource usage (quotas) to be manipulated through the IMAP
protocol.
This document obsoletes RFC 2087, but attempts to remain backwards This document obsoletes RFC 2087, but attempts to remain backwards
compatible whenever possible. compatible whenever possible.
Status of This Memo Status of This Memo
This Internet-Draft is submitted in full conformance with the This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/. Drafts is at https://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on 28 February 2022. This Internet-Draft will expire on 22 May 2022.
Copyright Notice Copyright Notice
Copyright (c) 2021 IETF Trust and the persons identified as the Copyright (c) 2021 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents (https://trustee.ietf.org/ Provisions Relating to IETF Documents (https://trustee.ietf.org/
license-info) in effect on the date of publication of this document. license-info) in effect on the date of publication of this document.
Please review these documents carefully, as they describe your rights Please review these documents carefully, as they describe your rights
skipping to change at page 2, line 38 skipping to change at page 2, line 38
1. Document Conventions . . . . . . . . . . . . . . . . . . . . 3 1. Document Conventions . . . . . . . . . . . . . . . . . . . . 3
2. Introduction and Overview . . . . . . . . . . . . . . . . . . 3 2. Introduction and Overview . . . . . . . . . . . . . . . . . . 3
3. Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Terms . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1. Resource . . . . . . . . . . . . . . . . . . . . . . . . 4 3.1. Resource . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1.1. Name . . . . . . . . . . . . . . . . . . . . . . . . 4 3.1.1. Name . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1.2. Definition . . . . . . . . . . . . . . . . . . . . . 4 3.1.2. Definition . . . . . . . . . . . . . . . . . . . . . 4
3.2. Quota Root . . . . . . . . . . . . . . . . . . . . . . . 5 3.2. Quota Root . . . . . . . . . . . . . . . . . . . . . . . 5
4. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 6 4. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.1. Commands . . . . . . . . . . . . . . . . . . . . . . . . 6 4.1. Commands . . . . . . . . . . . . . . . . . . . . . . . . 6
4.1.1. GETQUOTA . . . . . . . . . . . . . . . . . . . . . . 6 4.1.1. GETQUOTA . . . . . . . . . . . . . . . . . . . . . . 6
4.1.2. GETQUOTAROOT . . . . . . . . . . . . . . . . . . . . 6 4.1.2. GETQUOTAROOT . . . . . . . . . . . . . . . . . . . . 7
4.1.3. SETQUOTA . . . . . . . . . . . . . . . . . . . . . . 7 4.1.3. SETQUOTA . . . . . . . . . . . . . . . . . . . . . . 7
4.1.4. New STATUS attributes . . . . . . . . . . . . . . . . 9 4.1.4. New STATUS attributes . . . . . . . . . . . . . . . . 9
4.2. Responses . . . . . . . . . . . . . . . . . . . . . . . . 9 4.2. Responses . . . . . . . . . . . . . . . . . . . . . . . . 10
4.2.1. QUOTA . . . . . . . . . . . . . . . . . . . . . . . . 9 4.2.1. QUOTA . . . . . . . . . . . . . . . . . . . . . . . . 10
4.2.2. QUOTAROOT . . . . . . . . . . . . . . . . . . . . . . 10 4.2.2. QUOTAROOT . . . . . . . . . . . . . . . . . . . . . . 10
4.3. Response Codes . . . . . . . . . . . . . . . . . . . . . 10 4.3. Response Codes . . . . . . . . . . . . . . . . . . . . . 10
4.3.1. OVERQUOTA . . . . . . . . . . . . . . . . . . . . . . 10 4.3.1. OVERQUOTA . . . . . . . . . . . . . . . . . . . . . . 11
5. Resource Type Definitions . . . . . . . . . . . . . . . . . . 12 5. Resource Type Definitions . . . . . . . . . . . . . . . . . . 12
5.1. STORAGE . . . . . . . . . . . . . . . . . . . . . . . . . 12 5.1. STORAGE . . . . . . . . . . . . . . . . . . . . . . . . . 12
5.2. MESSAGE . . . . . . . . . . . . . . . . . . . . . . . . . 12 5.2. MESSAGE . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.3. MAILBOX . . . . . . . . . . . . . . . . . . . . . . . . . 13 5.3. MAILBOX . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.4. ANNOTATION-STORAGE . . . . . . . . . . . . . . . . . . . 13 5.4. ANNOTATION-STORAGE . . . . . . . . . . . . . . . . . . . 13
6. Interaction with IMAP ACL extension (RFC 4314) . . . . . . . 13 6. Interaction with IMAP ACL extension (RFC 4314) . . . . . . . 14
7. Formal syntax . . . . . . . . . . . . . . . . . . . . . . . . 13 7. Formal syntax . . . . . . . . . . . . . . . . . . . . . . . . 14
8. Security Considerations . . . . . . . . . . . . . . . . . . . 16 8. Security Considerations . . . . . . . . . . . . . . . . . . . 16
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 16 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17
9.1. Changes/additions to the IMAP4 capabilities registry . . 16 9.1. Changes/additions to the IMAP4 capabilities registry . . 17
9.2. IMAP quota resource type registry . . . . . . . . . . . . 16 9.2. IMAP quota resource type registry . . . . . . . . . . . . 17
9.3. Registrations of IMAP Quota Resource Types . . . . . . . 17 9.3. Registrations of IMAP Quota Resource Types . . . . . . . 18
10. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 18 10. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 19
11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 18 11. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 19
12. Changes since RFC 2087 . . . . . . . . . . . . . . . . . . . 19 12. Changes since RFC 2087 . . . . . . . . . . . . . . . . . . . 20
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 19 13. References . . . . . . . . . . . . . . . . . . . . . . . . . 20
13.1. Normative References . . . . . . . . . . . . . . . . . . 19 13.1. Normative References . . . . . . . . . . . . . . . . . . 20
13.2. Informative References . . . . . . . . . . . . . . . . . 20 13.2. Informative References . . . . . . . . . . . . . . . . . 21
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 20 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 21
1. Document Conventions 1. Document Conventions
In protocol examples, this document uses a prefix of "C: " to denote In protocol examples, this document uses a prefix of "C: " to denote
lines sent by the client to the server, and "S: " for lines sent by lines sent by the client to the server, and "S: " for lines sent by
the server to the client. Lines prefixed with "// " are comments the server to the client. Lines prefixed with "// " are comments
explaining the previous protocol line. These prefixes and comments explaining the previous protocol line. These prefixes and comments
are not part of the protocol. Lines without any of these prefixes are not part of the protocol. Lines without any of these prefixes
are continuations of the previous line, and no line break is present are continuations of the previous line, and no line break is present
in the protocol unless specifically mentioned. in the protocol before such lines unless specifically mentioned.
Again, for examples, the hierarchy separator on the IMAP server is
presumed to be "/" throughout. None of these assumptions is required
nor recommended by this document.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP "OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119] [RFC8174] when, and only when, they appear in all 14 [RFC2119] [RFC8174] when, and only when, they appear in all
capitals, as shown here. capitals, as shown here.
Other capitalised words are IMAP keywords [RFC3501][RFC9051] or Other capitalised words are IMAP keywords [RFC3501][RFC9051] or
keywords from this document. keywords from this document.
2. Introduction and Overview 2. Introduction and Overview
This document defines a couple of extension to the Internet Message This document defines a couple of extensions to the Internet Message
Access Protocol [RFC3501] for querying and manipulating Access Protocol [RFC3501] for querying and manipulating
administrative limits on resource usage (quotas). This extension is administrative limits on resource usage (quotas). This extension is
compatible with both IMAP4rev1 [RFC3501] and IMAP4rev2 [RFC9051]. compatible with both IMAP4rev1 [RFC3501] and IMAP4rev2 [RFC9051].
The capability "QUOTA", denotes a RFC2087 [RFC2087] compliant server. The capability "QUOTA", denotes a RFC2087 [RFC2087] compliant server.
Some responses and response codes defined in this document are not Some responses and response codes defined in this document are not
present in such servers (see Section 12 for more details), and present in such servers (see Section 12 for more details), and
clients MUST NOT rely on their presence in the absence of any clients MUST NOT rely on their presence in the absence of any
capability beginning with "QUOTA=". capability beginning with "QUOTA=".
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"QUOTA=" prefix for future IETF stream standard track, informational "QUOTA=" prefix for future IETF stream standard track, informational
or experimental extensions to this document. or experimental extensions to this document.
Quotas can be used to restrict clients for administrative reasons, Quotas can be used to restrict clients for administrative reasons,
but the QUOTA extension can also be used to indicate system limits but the QUOTA extension can also be used to indicate system limits
and current usage levels to clients. and current usage levels to clients.
Although RFC2087 [RFC2087] specified an IMAP4 QUOTA extension, and Although RFC2087 [RFC2087] specified an IMAP4 QUOTA extension, and
this has seen deployment in servers, it has seen little deployment in this has seen deployment in servers, it has seen little deployment in
clients. Since the meaning of the resources was left implementation- clients. Since the meaning of the resources was left implementation-
dependant, it was impossible for a client implementation to determine dependent, it was impossible for a client implementation to determine
which resources were supported, and impossible to determine which which resources were supported, and impossible to determine which
mailboxes were in a given quota root (see Section 3.2), without a mailboxes were in a given quota root (see Section 3.2), without a
priori knowledge of the implementation. priori knowledge of the implementation.
3. Terms 3. Terms
3.1. Resource 3.1. Resource
A resource has a name, a formal definition. A resource has a name, a formal definition.
3.1.1. Name 3.1.1. Name
The resource name is an atom, as defined in IMAP4rev1 [RFC3501]. The resource name is an atom, as defined in IMAP4rev1 [RFC3501].
These MUST be registered with IANA. Implementation specific These MUST be registered with IANA.
resources begin with "V-" .
Supported resource names MUST be advertised as a capability, by Supported resource names MUST be advertised as a capability, by
prepending the resource name with "QUOTA=RES-". A server compliant prepending the resource name with "QUOTA=RES-". A server compliant
with this specification is not required to support all reported with this specification is not required to support all reported
resource types on all quota roots. resource types on all quota roots.
3.1.2. Definition 3.1.2. Definition
The resource definition or document containing it, while not visible The resource definition or document containing it, while not visible
through the protocol, SHOULD be registered with IANA. through the protocol, SHOULD be registered with IANA.
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All resources which the server handles MUST be advertised in a All resources which the server handles MUST be advertised in a
CAPABILITY response/response code consisting of the resource name CAPABILITY response/response code consisting of the resource name
prefixed by "QUOTA=RES-". prefixed by "QUOTA=RES-".
The resources STORAGE (Section 5.1), MESSAGE (Section 5.2), MAILBOX The resources STORAGE (Section 5.1), MESSAGE (Section 5.2), MAILBOX
(Section 5.3) and ANNOTATION-STORAGE (Section 5.4) are defined in (Section 5.3) and ANNOTATION-STORAGE (Section 5.4) are defined in
this document. this document.
3.2. Quota Root 3.2. Quota Root
This document introduces a concept of a "quota root", as resource
limits can apply across multiple IMAP mailboxes.
Each mailbox has zero or more implementation-defined named "quota Each mailbox has zero or more implementation-defined named "quota
roots". Each quota root has zero or more resource limits (quotas). roots". Each quota root has zero or more resource limits (quotas).
All mailboxes that share the same named quota root share the resource All mailboxes that share the same named quota root share the resource
limits of the quota root. limits of the quota root.
Quota root names need not be mailbox names, nor is there any Quota root names need not be mailbox names, nor is there any
relationship defined by this document between a quota root name and a relationship defined by this document between a quota root name and a
mailbox name. A quota root name is an astring, as defined in IMAP4 mailbox name. A quota root name is an astring, as defined in IMAP4
[RFC3501]. It SHOULD be treated as an opaque string by any clients. [RFC3501]. It SHOULD be treated as an opaque string by any clients.
Quota roots are used since not all implementations may be able to Quota roots are used since not all implementations may be able to
calculate usage, or apply quotas, on arbitary mailboxes or mailbox calculate usage, or apply quotas, on arbitrary mailboxes or mailbox
hierarchies. hierarchies.
Not all resources may be limitable or calculatable for all quota Not all resources may be limitable or calculable for all quota roots.
roots. Further, not all resources may support all limits - some Further, not all resources may support all limits - some limits may
limits may be present in the underlying system. A server be present in the underlying system. A server implementation of this
implementation of this memo SHOULD advise the client of such inherent memo SHOULD advise the client of such inherent limits, by generating
limits, by generating QUOTA (Section 4.2.1) responses and SHOULD QUOTA (Section 4.2.1) responses, and SHOULD advise the client of
advise the client of which resources are limitable for a particular which resources are limitable for a particular quota root. A
quota root. A SETQUOTA (Section 4.1.3) command MAY also round a SETQUOTA (Section 4.1.3) command MAY also round a quota limit in an
quota limit in an implementation dependant way, if the granularity of implementation-dependent way, if the granularity of the underlying
the underlying system demands it. A client MUST be prepared for a system demands it. A client MUST be prepared for a SETQUOTA
SETQUOTA (Section 4.1.3) command to fail if a limit cannot be set. (Section 4.1.3) command to fail if a limit cannot be set.
Implementation Notes: This means that, for example under UNIX, a Implementation Notes: This means that, for example under UNIX, a
quota root may have a MESSAGE (Section 5.2) quota always set due to quota root may have a MESSAGE (Section 5.2) quota always set due to
the number of inodes available on the filesystem, and similarly the number of inodes available on the filesystem, and similarly
STORAGE (Section 5.1) may be rounded to the nearest block and limited STORAGE (Section 5.1) may be rounded to the nearest block and limited
by free filesystem space. by free filesystem space.
4. Definitions 4. Definitions
4.1. Commands 4.1. Commands
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Responses: REQUIRED untagged responses: QUOTA Responses: REQUIRED untagged responses: QUOTA
Result: OK - getquota completed Result: OK - getquota completed
NO - getquota error: no such quota root, permission denied NO - getquota error: no such quota root, permission denied
BAD - command unknown or arguments invalid BAD - command unknown or arguments invalid
The GETQUOTA command takes the name of a quota root and returns the The GETQUOTA command takes the name of a quota root and returns the
quota root's resource usage and limits in an untagged QUOTA response. quota root's resource usage and limits in an untagged QUOTA response.
The client can try using any of the resource types returned in (Names of quota roots applicable to a particular mailbox can be
CAPABILITY response (i.e. all capability items with "QUOTA=RES-" discovered by issuing the GETQUOTAROOT command, see Section 4.1.2.)
prefix), however the server is not required to support any specific Note that the server is not required to support any specific resource
resource type for any particular quota root. type (as advertised in the CAPABILITY response, i.e. all capability
items with the "QUOTA=RES-" prefix) for any particular quota root.
Example: Example:
S: * CAPABILITY [...] QUOTA QUOTA=RES-STORAGE [...] S: * CAPABILITY [...] QUOTA QUOTA=RES-STORAGE [...]
[...] [...]
C: G0001 GETQUOTA "!partition/sda4" C: G0001 GETQUOTA "!partition/sda4"
S: * QUOTA "!partition/sda4" (STORAGE 104 10923847) S: * QUOTA "!partition/sda4" (STORAGE 104 10923847)
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4.1.3. SETQUOTA 4.1.3. SETQUOTA
Arguments: quota root Arguments: quota root
list of resource limits list of resource limits
Responses: untagged responses: QUOTA Responses: untagged responses: QUOTA
Result: OK - setquota completed Result: OK - setquota completed
NO - setquota error: can't set that data NO - setquota error: can't set that data
BAD - command unknown or arguments invalid BAD - command unknown or arguments invalid
Note that unlike other command/responses/response codes defined in Note that unlike other command/responses/response codes defined in
this document, support for SETQUOTA command requires the server to this document, support for SETQUOTA command requires the server to
advertise "QUOTASET" capability. advertise "QUOTASET" capability.
The SETQUOTA command takes the name of a mailbox quota root and a The SETQUOTA command takes the name of a mailbox quota root and a
list of resource limits. The resource limits for the named quota list of resource limits. The resource limits for the named quota
root are changed to be the specified limits. Any previous resource root are changed to be the specified limits. Any previous resource
limits for the named quota root are discarded. limits for the named quota root are discarded, even resource limits
not explicitly listed in the SETQUOTA command. (For example, if the
quota root had both STORAGE and MESSAGE limits assigned to the quota
root before the SETQUOTA is called and the SETQUOTA only includes the
STORAGE limit, then the MESSAGE limit is removed from the quota
root.)
If the named quota root did not previously exist, an implementation If the named quota root did not previously exist, an implementation
may optionally create it and change the quota roots for any number of may optionally create it and change the quota roots for any number of
existing mailboxes in an implementation-defined manner. existing mailboxes in an implementation-defined manner.
If the implementation chooses to change the quota roots for some If the implementation chooses to change the quota roots for some
existing mailboxes such changes SHOULD be announced with untagged existing mailboxes such changes SHOULD be announced with untagged
QUOTA responses. QUOTA responses.
Example: Example:
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C: S0001 SETQUOTA "#user/alice" (STORAGE 510) C: S0001 SETQUOTA "#user/alice" (STORAGE 510)
S: * QUOTA "#user/alice" (STORAGE 58 512) S: * QUOTA "#user/alice" (STORAGE 58 512)
// The server has rounded the STORAGE quota limit requested to the // The server has rounded the STORAGE quota limit requested to the
nearest 512 blocks of 1024 octects, or else another client has nearest 512 blocks of 1024 octects, or else another client has
performed a near simultaneous SETQUOTA, using a limit of 512. performed a near simultaneous SETQUOTA, using a limit of 512.
S: S0001 OK Rounded quota S: S0001 OK Rounded quota
C: S0002 SETQUOTA "!partition/sda4" (STORAGE 99999999) C: S0002 SETQUOTA "!partition/sda4" (STORAGE 99999999)
S: * QUOTA "!partition/sda4" (STORAGE 104 10923847) S: * QUOTA "!partition/sda4" (STORAGE 104 10923847)
// The server has not changed the quota, since this is a // The server has not changed the quota, since this is a
filesystem limit, and cannot be changed. The QUOTA response here filesystem limit, and cannot be changed. The QUOTA response here
is entirely optional. is entirely optional.
S: S0002 NO Cannot change system limit S: S0002 NO Cannot change system limit
4.1.4. New STATUS attributes 4.1.4. New STATUS attributes
DELETED and DELETED-STORAGE status data items allow to estimate the DELETED and DELETED-STORAGE status data items allow to estimate the
amount of resource freed by an EXPUNGE on a mailbox. amount of resource freed by an EXPUNGE on a mailbox.
DELETED status data item requests the server to return the number of The DELETED status data item requests the server to return the number
messages with \Deleted flag set. DELETED status data item is only of messages with \Deleted flag set. The DELETED status data item is
required to be implemented when the server advertises QUOTA=RES- only required to be implemented when the server advertises QUOTA=RES-
MESSAGE capability. MESSAGE capability.
DELETED-STORAGE status data item requests the server to return the The DELETED-STORAGE status data item requests the server to return
amount of storage space that can be reclaimed by performing EXPUNGE the amount of storage space that can be reclaimed by performing
on the mailbox. The server SHOULD return the exact value, however it EXPUNGE on the mailbox. The server SHOULD return the exact value,
is recognized that the server may have to do non-trivial amount of however it is recognized that the server may have to do non-trivial
work to calculate it. If the calculation of the exact value would amount of work to calculate it. If the calculation of the exact
take a long time, the server MAY instead return the sum of value would take a long time, the server MAY instead return the sum
RFC822.SIZEs of messages with the \Deleted flag set. DELETED-STORAGE of RFC822.SIZEs of messages with the \Deleted flag set. The DELETED-
status data item is only required to be implemented when the server STORAGE status data item is only required to be implemented when the
advertises QUOTA=RES-STORAGE capability. server advertises QUOTA=RES-STORAGE capability.
Example: Example:
S: * CAPABILITY [...] QUOTA QUOTA=RES-STORAGE QUOTA=RES-MESSAGE S: * CAPABILITY [...] QUOTA QUOTA=RES-STORAGE QUOTA=RES-MESSAGE
[...] [...]
[...] [...]
C: S0003 STATUS INBOX (MESSAGES DELETED DELETED-STORAGE) C: S0003 STATUS INBOX (MESSAGES DELETED DELETED-STORAGE)
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4.2. Responses 4.2. Responses
The following responses may be sent by the server. The following responses may be sent by the server.
4.2.1. QUOTA 4.2.1. QUOTA
Data: quota root name Data: quota root name
list of resource names, usages, and limits list of resource names, usages, and limits
This response occurs as a result of a GETQUOTA or GETQUOTAROOT This response occurs as a result of a GETQUOTA, a GETQUOTAROOT or a
command. The first string is the name of the quota root for which SETQUOTA command. The first string is the name of the quota root for
this quota applies. which this quota applies.
The name is followed by a S-expression format list of the resource The name is followed by a S-expression format list of the resource
usage and limits of the quota root. The list contains zero or more usage and limits of the quota root. The list contains zero or more
triplets. Each triplet contains a resource name, the current usage triplets. Each triplet contains a resource name, the current usage
of the resource, and the resource limit. of the resource, and the resource limit.
Resources not named in the list are not limited in the quota root. Resources not named in the list are not limited in the quota root.
Thus, an empty list means there are no administrative resource limits Thus, an empty list means there are no administrative resource limits
in the quota root. in the quota root.
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4.2.2. QUOTAROOT 4.2.2. QUOTAROOT
Data: mailbox name Data: mailbox name
zero or more quota root names zero or more quota root names
This response occurs as a result of a GETQUOTAROOT command. The This response occurs as a result of a GETQUOTAROOT command. The
first string is the mailbox and the remaining strings are the names first string is the mailbox and the remaining strings are the names
of the quota roots for the mailbox. of the quota roots for the mailbox.
Example: Examples:
S: * QUOTAROOT INBOX "" S: * QUOTAROOT INBOX ""
// The INBOX mailbox is covered by a single quota root with name "".
S: * QUOTAROOT comp.mail.mime S: * QUOTAROOT comp.mail.mime
4.3. Response Codes // The comp.mail.mime mailbox has no quota root associated with it,
but one can be created.
4.3. Response Codes
4.3.1. OVERQUOTA 4.3.1. OVERQUOTA
OVERQUOTA response code SHOULD be returned in the tagged NO response OVERQUOTA response code SHOULD be returned in the tagged NO response
to an APPEND/COPY/MOVE when the addition of the message(s) puts the to an APPEND/COPY/MOVE when the addition of the message(s) puts the
target mailbox over any one of its quota limits. target mailbox over any one of its quota limits.
Example 1: C: A003 APPEND saved-messages (\Seen) {326} Example 1: C: A003 APPEND saved-messages (\Seen) {326}
S: + Ready for literal data S: + Ready for literal data
C: Date: Mon, 7 Feb 1994 21:52:25 -0800 (PST) C: Date: Mon, 7 Feb 1994 21:52:25 -0800 (PST)
C: From: Fred Foobar <foobar@Blurdybloop.example> C: From: Fred Foobar <foobar@Blurdybloop.example>
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C: To: mooch@owatagu.siam.edu.example C: To: mooch@owatagu.siam.edu.example
C: Message-Id: <B27397-0100000@Blurdybloop.example> C: Message-Id: <B27397-0100000@Blurdybloop.example>
C: MIME-Version: 1.0 C: MIME-Version: 1.0
C: Content-Type: TEXT/PLAIN; CHARSET=US-ASCII C: Content-Type: TEXT/PLAIN; CHARSET=US-ASCII
C: C:
C: Hello Joe, do you think we can meet at 3:30 tomorrow? C: Hello Joe, do you think we can meet at 3:30 tomorrow?
C: C:
S: * NO [OVERQUOTA] Soft quota has been exceeded S: * NO [OVERQUOTA] Soft quota has been exceeded
S: A003 OK [APPENDUID 38505 3955] APPEND completed S: A003 OK [APPENDUID 38505 3955] APPEND completed
Example 3: C: A003 COPY 2:4 MEETING Example 3: C: A004 COPY 2:4 MEETING
S: * NO [OVERQUOTA] Soft quota has been exceeded S: * NO [OVERQUOTA] Soft quota has been exceeded
S: A003 OK [COPYUID 38505 304,319:320 3956:3958] COPY S: A004 OK [COPYUID 38505 304,319:320 3956:3958] COPY
command completed command completed
5. Resource Type Definitions 5. Resource Type Definitions
The following resource types are defined in this memo. A server The following resource types are defined in this memo. A server
supporting a resource type MUST advertise this as a CAPABILITY with a supporting a resource type MUST advertise this as a CAPABILITY with a
name consisting of the resource name prefixed by "QUOTA=RES-". A name consisting of the resource name prefixed by "QUOTA=RES-". A
server MAY support mupltiple resource types, and MUST advertise all server MAY support multiple resource types, and MUST advertise all
resource types it supports. resource types it supports.
5.1. STORAGE 5.1. STORAGE
The physical space estimate, in units of 1024 octets, of the The physical space estimate, in units of 1024 octets, of the
mailboxes governed by the quota root. This MAY not be the same as mailboxes governed by the quota root. This MAY not be the same as
the sum of the RFC822.SIZE of the messages. Some implementations MAY the sum of the RFC822.SIZE of the messages. Some implementations MAY
include metadata sizes for the messages and mailboxes, other include metadata sizes for the messages and mailboxes, other
implementations MAY store messages in such a way that the physical implementations MAY store messages in such a way that the physical
space used is smaller, for example due to use of compression. space used is smaller, for example due to use of compression.
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use the usage figure for anything other than informational purposes, use the usage figure for anything other than informational purposes,
for example, they MUST NOT refuse to APPEND a message if the limit for example, they MUST NOT refuse to APPEND a message if the limit
less the usage is smaller than the RFC822.SIZE divided by 1024 of the less the usage is smaller than the RFC822.SIZE divided by 1024 of the
message, but it MAY warn about such condition. message, but it MAY warn about such condition.
The usage figure may change as a result of performing actions not The usage figure may change as a result of performing actions not
associated with adding new messages to the mailbox, such as SEARCH, associated with adding new messages to the mailbox, such as SEARCH,
since this may increase the amount of metadata included in the since this may increase the amount of metadata included in the
calculations. calculations.
When the server supports this resource type, it MUST also support When the server supports this resource type, it MUST also support the
DELETED-STORAGE status data item. DELETED-STORAGE status data item.
Support for this resource MUST be indicated by the server by Support for this resource MUST be indicated by the server by
advertising the CAPABILITY "QUOTA=RES-STORAGE". advertising the CAPABILITY "QUOTA=RES-STORAGE".
A resource named the same was also given as an example in RFC2087 A resource named the same was also given as an example in RFC2087
[RFC2087]. This document provides a more precise definition. [RFC2087]. This document provides a more precise definition.
5.2. MESSAGE 5.2. MESSAGE
The number of messages stored within the mailboxes governed by the The number of messages stored within the mailboxes governed by the
quota root. This MUST be an exact number, however, clients MUST NOT quota root. This MUST be an exact number, however, clients MUST NOT
assume that a change in the usage indicates a change in the number of assume that a change in the usage indicates a change in the number of
messages available, since the quota root may include mailboxes the messages available, since the quota root may include mailboxes the
client has no access to. client has no access to.
When the server supports this resource type, it MUST also support When the server supports this resource type, it MUST also support the
DELETED status data item. DELETED status data item.
Support for this resource MUST be indicated by the server by Support for this resource MUST be indicated by the server by
advertising the CAPABILITY "QUOTA=RES-MESSAGE". advertising the CAPABILITY "QUOTA=RES-MESSAGE".
A resource named the same was also given as an example in RFC2087 A resource named the same was also given as an example in RFC2087
[RFC2087]. This document provides a more precise definition. [RFC2087]. This document provides a more precise definition.
5.3. MAILBOX 5.3. MAILBOX
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+-------------------+-+-+---+---+---+---+---+---+---+---+-----+-----+ +-------------------+-+-+---+---+---+---+---+---+---+---+-----+-----+
| GETQUOTAROOT | |*| | | | | | | | | | * | | GETQUOTAROOT | |*| | | | | | | | | | * |
+-------------------+-+-+---+---+---+---+---+---+---+---+-----+-----+ +-------------------+-+-+---+---+---+---+---+---+---+---+-----+-----+
| SETQUOTA | | | | | | | | | | + | | | | SETQUOTA | | | | | | | | | | + | | |
+-------------------+-+-+---+---+---+---+---+---+---+---+-----+-----+ +-------------------+-+-+---+---+---+---+---+---+---+---+-----+-----+
Table 1 Table 1
See Section 4 of RFC 4314 for conventions used in this table. See Section 4 of RFC 4314 for conventions used in this table.
Legend:
+ - The right is required
* - Only one of the rights marked with * is required
"Any" - at least one of the "l", "r", "i", "k", "x", "a" rights is
required
"Non" - no rights required to perform the command
Note that which permissions are needed in order to perform
GETQUOTAROOT command depends on the quota resource type being
requested. For example, a quota on number of messages (MESSAGE
resource type) or total size of messages (STORAGE resource type)
requires "r" right on the mailbox in question, since the quota
involved would reveal information about the number (or total size) of
messages in the mailbox. By comparison, the MAILBOX resource type
doesn't require any right.
7. Formal syntax 7. Formal syntax
The following syntax specification uses the Augmented Backus-Naur The following syntax specification uses the Augmented Backus-Naur
Form (ABNF) notation as specified in [ABNF]. Form (ABNF) notation as specified in [ABNF].
Non-terminals referenced but not defined below are as defined by Non-terminals referenced but not defined below are as defined by
IMAP4 [RFC3501]. IMAP4 [RFC3501].
Except as noted otherwise, all alphabetic characters are case- Except as noted otherwise, all alphabetic characters are case-
insensitive. The use of upper or lower case characters to define insensitive. The use of upper or lower case characters to define
skipping to change at page 14, line 38 skipping to change at page 15, line 35
")" ")"
setquota-resource = resource-name SP resource-limit setquota-resource = resource-name SP resource-limit
quota-root-name = astring quota-root-name = astring
resource-limit = number64 resource-limit = number64
resource-name = "STORAGE" / "MESSAGE" / "MAILBOX" / resource-name = "STORAGE" / "MESSAGE" / "MAILBOX" /
"ANNOTATION-STORAGE" / resource-name-vnd / "ANNOTATION-STORAGE" / resource-name-ext
resource-name-ext
resource-name-vnd = "V-" atom
;; Vendor specific, must be registered with IANA.
;; The "V-" prefix should be followed by a domain
name
;; under vendor's control.
resource-name-ext = atom resource-name-ext = atom
;; Not starting with V- and defined
;; in a Standard Track or Experimental RFC
resource-names = "(" [resource-name *(SP resource-name)] ")" ;; Future resource registrations
resource-usage = number64 resource-usage = number64
;; must be less than corresponding resource-limit ;; must be less than corresponding resource-limit
capability-quota = capa-quota-res / "QUOTASET" capability-quota = capa-quota-res / "QUOTASET"
;; One or more capa-quota-res must be returned. ;; One or more capa-quota-res must be returned.
;; Also "QUOTASET" can optionally be returned. ;; Also "QUOTASET" can optionally be returned.
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;; must be less than corresponding resource-limit ;; must be less than corresponding resource-limit
capability-quota = capa-quota-res / "QUOTASET" capability-quota = capa-quota-res / "QUOTASET"
;; One or more capa-quota-res must be returned. ;; One or more capa-quota-res must be returned.
;; Also "QUOTASET" can optionally be returned. ;; Also "QUOTASET" can optionally be returned.
capa-quota-res = "QUOTA=RES-" resource-name capa-quota-res = "QUOTA=RES-" resource-name
status-att =/ "DELETED" / "DELETED-STORAGE" status-att =/ "DELETED" / "DELETED-STORAGE"
;; DELETED status data item MUST be supported ;; DELETED status data item MUST be supported
;; when "QUOTA=RES-MESSAGE" capability is ;; when "QUOTA=RES-MESSAGE" capability is
;; advertised. ;; advertised.
;; DELETED-STORAGE status data item MUST be ;; DELETED-STORAGE status data item MUST be
;; supported when "QUOTA=RES-STORAGE" capability ;; supported when "QUOTA=RES-STORAGE" capability
;; is advertised. ;; is advertised.
status-att-val =/ status-att-deleted / status-att-val =/ status-att-deleted /
status-att-deleted-storage status-att-deleted-storage
status-att-deleted =/ "DELETED" SP number status-att-deleted = "DELETED" SP number
;; DELETED status data item MUST be supported ;; DELETED status data item MUST be supported
;; when "QUOTA=RES-MESSAGE" capability is ;; when "QUOTA=RES-MESSAGE" capability is
;; advertised. ;; advertised.
status-att-deleted-storage =/ "DELETED-STORAGE" SP number64 status-att-deleted-storage = "DELETED-STORAGE" SP number64
;; DELETED-STORAGE status data item MUST be ;; DELETED-STORAGE status data item MUST be
;; supported when "QUOTA=RES-STORAGE" capability ;; supported when "QUOTA=RES-STORAGE" capability
;; is advertised. ;; is advertised.
resp-text-code =/ "OVERQUOTA" resp-text-code =/ "OVERQUOTA"
number64 = <Defined in RFC 9051> number64 = <Defined in RFC 9051>
8. Security Considerations 8. Security Considerations
Implementors should be careful to make sure the implementation of Implementors should be careful to make sure the implementation of
these commands does not violate the site's security policy. The these commands does not violate the site's security policy. The
resource usage of other users is likely to be considered confidential resource usage of other users is likely to be considered confidential
information and should not be divulged to unauthorized persons. In information and should not be divulged to unauthorized persons. In
particular, no quota information should be disclosed to anonymous particular, no quota information should be disclosed to anonymous
users. users.
As for any resource shared across users (for example a quota root
attached to a set of shared mailboxes), a user that can consume or
render unusable the resource can affect the resources available to
the other users; this might occur, for example, by a user with
permission to execute SETQUOTA setting an artificially small value.
Note that computing resource usage might incur a heavy load on the
server. Server implementers should consider implementation
techniques that lower load on servers, such as caching of resource
usage information or usage of less precise computations when under
heavy load.
9. IANA Considerations 9. IANA Considerations
9.1. Changes/additions to the IMAP4 capabilities registry 9.1. Changes/additions to the IMAP4 capabilities registry
IMAP4 capabilities are registered by publishing a standards track or IMAP4 capabilities are registered by publishing a standards track or
IESG approved Informational or Experimental RFC. The registry is IESG approved Informational or Experimental RFC. The registry is
currently located at: currently located at:
http://www.iana.org/assignments/imap4-capabilities https://www.iana.org/assignments/imap4-capabilities
IANA is requested to update definition of the QUOTA extension to IANA is requested to update definition of the QUOTA extension to
point to this document. IANA is also requested to add the "QUOTASET" point to this document. IANA is also requested to add the "QUOTASET"
capability to the IMAP4 capabilities registry, with this document as capability to the IMAP4 capabilities registry, with this document as
the reference. the reference.
IANA is requested to reserve the prefix "QUOTA=RES-" in the IMAP4 IANA is requested to reserve the prefix "QUOTA=RES-" in the IMAP4
capabilities registry and add a pointer to this document and to the capabilities registry and add a pointer to this document and to the
IMAP quota resource type registry (see Section 9.2). IMAP quota resource type registry (see Section 9.2).
IANA is requested to reserve all other capabilities starting with IANA is requested to reserve all other capabilities starting with
"QUOTA=" prefix for future IETF stream standard track, informational "QUOTA=" prefix for future IETF Stream extensions to this document.
or experimental extensions to this document.
9.2. IMAP quota resource type registry 9.2. IMAP quota resource type registry
IANA is requested to create a new registry for IMAP quota resource IANA is requested to create a new registry for IMAP quota resource
types. Registration policy for this registry is "Specification types. Registration policy for this registry is "Specification
Required". When registering a new quota resource type, the Required". When registering a new quota resource type, the
registrant need to provide the following: Name of the quota resource registrant need to provide the following: Name of the quota resource
type, Author/Change Controller name and email address, short type, Author/Change Controller name and email address, short
description, extra (if any) required and optional IMAP commands/ description, extra (if any) required and optional IMAP commands/
responses, and a reference to a specification that describes the responses, and a reference to a specification that describes the
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governed by the quota root. governed by the quota root.
Extra required IMAP commands/responses: DELETED STATUS request data Extra required IMAP commands/responses: DELETED STATUS request data
item and response data item item and response data item
Extra optional IMAP commands/responses: N/A Extra optional IMAP commands/responses: N/A
Reference: Section 5.2 of RFCXXXX Reference: Section 5.2 of RFCXXXX
Name of the quota resource type: MAILBOX Name of the quota resource type: MAILBOX
Author: Alexey Melnikov <alexey.melnikov@isode.com> Author: Alexey Melnikov <alexey.melnikov@isode.com>
Change Controller: IESG <iesg@ietf.org> Change Controller: IESG <iesg@ietf.org>
Description: The number of mailboxes governed by the quota root. Description: The number of mailboxes governed by the quota root.
Extra required IMAP commands/responses: N/A Extra required IMAP commands/responses: N/A
Extra optional IMAP commands/responses: N/A Extra optional IMAP commands/responses: N/A
Reference: Section 5.3 of RFCXXXX Reference: Section 5.3 of RFCXXXX
Name of the quota resource type: Name of the quota resource type: ANNOTATION-STORAGE
Author: Alexey Melnikov <alexey.melnikov@isode.com> Author: Alexey Melnikov <alexey.melnikov@isode.com>
Change Controller: IESG <iesg@ietf.org> Change Controller: IESG <iesg@ietf.org>
Description: The maximum size of all annotations [RFC5257], in units Description: The maximum size of all annotations [RFC5257], in units
of 1024 octets, associated with all messages in the mailboxes of 1024 octets, associated with all messages in the mailboxes
governed by the quota root. governed by the quota root.
Extra required IMAP commands/responses: N/A Extra required IMAP commands/responses: N/A
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Reference: Section 5.4 of RFCXXXX Reference: Section 5.4 of RFCXXXX
10. Contributors 10. Contributors
Dave Cridland wrote lots of text in an earlier draft that became the Dave Cridland wrote lots of text in an earlier draft that became the
basis for this document. basis for this document.
11. Acknowledgments 11. Acknowledgments
Editors of this document would like to thank the following people who Editor of this document would like to thank the following people who
provided useful comments or participated in discussions that lead to provided useful comments or participated in discussions that lead to
this update to RFC 2087: John Myers, Cyrus Daboo, Lyndon Nerenberg this update to RFC 2087: John Myers, Cyrus Daboo, Lyndon Nerenberg,
Benjamin Kaduk, Roman Danyliw, Eric Vyncke.
This document is a revision of RFC 2087. It borrows a lot of text This document is a revision of RFC 2087. It borrows a lot of text
from RFC 2087. Thus work of the RFC 2087 author John Myers is from RFC 2087. Thus work of the RFC 2087 author John Myers is
appreciated. appreciated.
12. Changes since RFC 2087 12. Changes since RFC 2087
This document is a revision of RFC 2087. It tries to clarify meaning This document is a revision of RFC 2087. It tries to clarify the
of different terms used by RFC 2087. It also provides more examples, meaning of different terms used by RFC 2087. It also provides more
gives guidance on allowed server behaviour, defines IANA registry for examples, gives guidance on allowed server behaviour, defines IANA
quota resource types and provides initial registrations for 3 of registry for quota resource types and provides initial registrations
them. for 4 of them.
When compared with RFC 2087, this document defines two more commonly When compared with RFC 2087, this document defines two more commonly
used resource type, adds optional OVERQUOTA response code and defines used resource type, adds optional OVERQUOTA response code and defines
two extra STATUS data items ("DELETED" and "DELETED-STORAGE") that two extra STATUS data items ("DELETED" and "DELETED-STORAGE"). The
must be implemented. For extensibility quota usage and quota limits DELETED STATUS data item must be implemented if the QUOTA=RES-MESSAGE
are now 63 bit unsigned integers. capability is advertised. The DELETED-STORAGE STATUS data item must
be implemented if the QUOTA=RES-STORAGE capability is advertised.
For extensibility quota usage and quota limits are now 63 bit
unsigned integers.
13. References 13. References
13.1. Normative References 13.1. Normative References
[ABNF] Crocker, D., Ed. and P. Overell, Ed., "Augmented BNF for [ABNF] Crocker, D., Ed. and P. Overell, Ed., "Augmented BNF for
Syntax Specifications: ABNF", RFC 5234, January 2008, Syntax Specifications: ABNF", RFC 5234, January 2008,
<ftp://ftp.isi.edu/in-notes/rfc5234.txt>. <https://www.rfc-editor.org/info/rfc5234>.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997, DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>. <https://www.rfc-editor.org/info/rfc2119>.
[RFC3501] Crispin, M., "INTERNET MESSAGE ACCESS PROTOCOL - VERSION [RFC3501] Crispin, M., "INTERNET MESSAGE ACCESS PROTOCOL - VERSION
4rev1", RFC 3501, DOI 10.17487/RFC3501, March 2003, 4rev1", RFC 3501, DOI 10.17487/RFC3501, March 2003,
<https://www.rfc-editor.org/info/rfc3501>. <https://www.rfc-editor.org/info/rfc3501>.
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