Network Working Group C. Newman Internet Draft: ACAP Innosoft Document: draft-ietf-acap-spec-02.txt J. G. Myers Expire in six months March 1997 ACAP -- Application Configuration Access Protocol Status of this Memo This document is an Internet Draft. 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. Internet Drafts may be updated, replaced, or obsoleted by other documents at any time. It is not appropriate to use Internet Drafts as reference material or to cite them other than as a ``working draft'' or ``work in progress``. To learn the current status of any Internet-Draft, please check the 1id-abstracts.txt listing contained in the Internet-Drafts Shadow Directories on ds.internic.net, nic.nordu.net, ftp.isi.edu, or munnari.oz.au. This document suggests a proposed protocol for the Internet community, and requests discussion and suggestions for improvements. Distribution of this draft is unlimited. The protocol discussed in this document is experimental and subject to change. Persons planning on either implementing or using this protocol are STRONGLY URGED to get in touch with the author before embarking on such a project. Abstract The Application Configuration Access Protocol (ACAP) is designed to support remote storage and access of program option, configuration and preference information. Newman [Page i]
Internet DRAFT ACAP March 21, 1997 Table of Contents Status of this Memo ............................................... i Abstract .......................................................... i ACAP Protocol Specification ....................................... 1 0. Changes from Last Internet Draft ......................... 1 0.1. Open Issues .............................................. 2 1. Conventions Used in this Document ........................ 3 2. Protocol Overview ........................................ 3 2.1. Link Level ............................................... 3 2.2. Commands and Responses ................................... 3 2.2.1. Client Protocol Sender and Server Protocol Receiver ...... 3 2.2.2. Server Protocol Sender and Client Protocol Receiver ...... 4 2.3. State and Flow Diagram ................................... 5 2.3.1. Non-Authenticated State .................................. 5 2.3.2. Authenticated State ...................................... 5 2.3.3. Logout State ............................................. 6 2.4. Operational Considerations ............................... 6 2.4.1. Untagged Status Updates .................................. 6 2.4.2. Response when no Command in Progress ..................... 6 2.4.3. Autologout Timer ......................................... 7 2.4.4. Multiple Commands in Progress ............................ 7 2.5. Datasets and Entries ..................................... 7 2.6. Predefined Attributes .................................... 7 2.7. Attribute metadata ....................................... 9 2.8. Operational Command Overview ............................. 9 3. Protocol Elements ........................................ 10 3.1. Data Formats ............................................. 10 3.1.1. Atom ..................................................... 10 3.1.2. Number ................................................... 10 3.1.3. String ................................................... 10 3.1.3.1. 8-bit and Binary Strings ................................. 11 3.2. ACAP URL scheme .......................................... 11 3.2.1. ACAP URL User Name and Authentication Mechanism .......... 12 3.2.2. Relative ACAP URLs ....................................... 12 3.3. Contexts ................................................. 13 3.4. Orderings ................................................ 13 3.5. Server Status Responses .................................. 14 3.6. Server Command Continuation Request ...................... 15 4. Protocol Specification ................................... 16 4.1. Initial Connection ....................................... 16 4.1.1. ACAP Untagged Response ................................... 16 4.2. Any State ................................................ 17 Newman [Page iii]
Internet DRAFT ACAP March 21, 1997 4.2.1. NOOP Command ............................................. 17 4.2.2. LOGOUT Command ........................................... 18 4.2.3. OK Response .............................................. 18 4.2.4. NO Response .............................................. 18 4.2.5. BAD Response ............................................. 19 4.2.6. BYE Untagged Response .................................... 19 4.3. Non-Authenticated State .................................. 20 4.3.1. AUTHENTICATE Command ..................................... 20 4.3.2. LOGIN Command ............................................ 22 4.4. Searching ................................................ 22 4.4.1. SEARCH Command ........................................... 22 4.4.2. ENTRY Intermediate Response .............................. 26 4.4.3. MODTIME Intermediate Response ............................ 26 4.5. Contexts ................................................. 27 4.5.1. FREECONTEXT Command ...................................... 27 4.5.2. UPDATECONTEXT Command .................................... 27 4.5.3. ADDTO Untagged Response .................................. 28 4.5.4. REMOVEFROM Untagged Response ............................. 28 4.5.5. CHANGE Untagged Response ................................. 28 4.5.6. MODTIME Untagged Response ................................ 29 4.6. Dataset modification ..................................... 29 4.6.1. STORE Command ............................................ 29 4.6.2. DELETE Command ........................................... 30 4.6.3. DELETEDSINCE Command ..................................... 30 4.6.4. DELETED Intermediate Response ............................ 31 4.7. Access Control Lists ..................................... 31 4.7.1. SETACL Command ........................................... 33 4.7.2. DELETEACL Command ........................................ 33 4.7.3. MYRIGHTS Command ......................................... 34 4.7.4. MYRIGHTS Intermediate Response ........................... 34 4.8. Quotas ................................................... 35 4.8.1. SETQUOTA Command ......................................... 35 4.8.2. GETQUOTA Command ......................................... 35 4.8.3. QUOTA Intermediate Response .............................. 36 4.9. Advisory locking ......................................... 36 4.9.1. LOCK Command ............................................. 36 4.9.2. UNLOCK Command ........................................... 37 4.10. Extensions ............................................... 38 5. Dataset Management ....................................... 39 5.1. Dataset Inheritance ...................................... 39 5.2. Dataset attributes ....................................... 39 6. Namespace conventions .................................... 40 6.1. Dataset Namespace ........................................ 40 6.2. Attribute Namespace ...................................... 40 7. Registration procedures .................................. 40 7.1. Ordering Functions ....................................... 41 7.2. ACAP Capabilities ........................................ 41 7.3. Dataset Classes .......................................... 42 Newman [Page iv]
Internet DRAFT ACAP March 21, 1997 7.4. Private Attribute Subtree ................................ 42 8. Formal Syntax ............................................ 43 9. Security Considerations .................................. 50 10. Authors' Addresses ....................................... 50 Appendices ........................................................ 51 A. References ............................................... 51 B. ACAP Keyword Index ....................................... 52 Newman [Page v]
Internet DRAFT ACAP March 21, 1997 ACAP Protocol Specification 0. Changes from Last Internet Draft 1) Added reference to definitions of MUST, SHOULD, etc. 2) Removed last mention of "NIL". 3) Renamed "name" to "entry". 4) Datasets are ordered in a server-determined manner. 5) "acl" metadata is read-write, changing "acl" metadata cases change in modtime. 6) return error on fetch of undefined metadata. 7) Added "subdataset" attribute and discussion of dataset hierarchy. 8) Changed "request response" to "request", and "result response" to "result" to simplify the text. 9) Removed "Child Dataset Attributes" and added "Operational Command Overview" 10) Restructured document a bit, adding a "protocol elements" section 11) Added "*" rule to the RETURN search modifier. 12) Added the DEPTH search modifier. 13) Added predefined orderings. 14) Added ACAP URL scheme 15) Removed NOTIFYCONTEXT command, added NOTIFYCONTEXT search modifier. 16) DELETEDFROM -> intermediate DELETED response 17) Added second argument to LIMIT search modifier. 18) Added "[" and "]" to atom_specials to deal with special information tokens cleanly removed "*" and "%" 19) made resp_text into quoted string to simplify parsing. Newman [Page 1]
Internet DRAFT ACAP March 21, 1997 20) Added SASL list to Capability greeting. 21) Removed ACL, LISTRIGHTS, GETACL, NOACL in favor of dataset management attributes 22) Added AND to SEARCH keys and removed parentheses around SEARCH keys. 23) simplified MYRIGHTS command and result 24) Simplified STORE and DELETE using entry-path 25) Remove locking of entire dataset. Add MODTIME intermediate result to LOCK command. 26) Added GETQUOTA and SETQUOTA. 27) Astring is removed from the grammar, except for LOGIN. 28) Changed term "shadow" to "inherit" 29) Added dataset management section 30) Added sort-hint 31) Added QUOTA and PERMISSION response codes 32) Added registration procedures 0.1. Open Issues 1) Document structure: do you like it? 2) There was discomfort at the last IETF about removing an attribute by storing "" into it. 3) Need to define precise Unicode-based ordering function, if one exists that isn't a nightmare to implement. If it is a nightmare to implement, we can make it a SHOULD rather than a MUST. 4) Synchronization issues. Context position numbers have same synchronization problems as IMAP sequence numbers. Should we disallow untagged responses between commands and copy the IDLE extension model from IMAP? 5) Should we build in a client-id command for logging/debugging purposes? Newman [Page 2]
Internet DRAFT ACAP March 21, 1997 6) Should we remove the LOGIN command and define a DUMB SASL mechanism to replace it? 7) Do we really need the LOCK/UNLOCK commands? 1. Conventions Used in this Document In examples, "C:" and "S:" indicate lines sent by the client and server respectively. The key words "MUST", "MUST NOT", "SHOULD", "SHOULD NOT", and "MAY" in this document are to be interpreted as described in RFC xxxx. The protocol syntax specification uses the Augmented Backus-Naur Form (ABNF) notation as specified in [IMAIL] with one exception; the delimiter used with the "#" construct is a single space (SPACE) and not one or more commas. 2. Protocol Overview 2.1. Link Level The ACAP protocol assumes a reliable data stream such as provided by TCP. When TCP is used, an ACAP server listens on port 674. 2.2. Commands and Responses An ACAP session consists of the establishment of a client/server connection, an initial greeting from the server, and client/server interactions. These client/server interactions consist of a client command, server data, and a server completion result. All interactions transmitted by client and server are in the form of lines; that is, strings that end with a CRLF. The protocol receiver of an ACAP client or server is either reading a line, or is reading a sequence of octets with a known count followed by a line. Both clients and servers must be capable of handling lines of arbitrary length. 2.2.1. Client Protocol Sender and Server Protocol Receiver The client command begins an operation. Each client command is prefixed with a identifier (typically a short alphanumeric string, e.g. A0001, A0002, etc.) called a "tag". A different tag is generated by the client for each command. Newman [Page 3]
Internet DRAFT ACAP March 21, 1997 There are two cases in which a line from the client does not represent a complete command. In one case, a command argument is quoted with an octet count (see the description of literal in section <section>); in the other case, the command arguments require server feedback (see the AUTHENTICATE command). In some of these cases, the server sends a command continuation request if it is ready for the next part of the command. This response is prefixed with the token "+". Note: If, instead, the server detected an error in the command, it sends a BAD completion response with tag matching the command (as described below) to reject the command and prevent the client from sending any more of the command. It is also possible for the server to send a completion or intermediate response for some other command (if multiple commands are in progress), or untagged data. In either case, the command continuation request is still pending; the client takes the appropriate action for the response, and reads another response from the server. The protocol receiver of an ACAP server reads a command line from the client, parses the command and its arguments, and transmits server data and a server command completion result. 2.2.2. Server Protocol Sender and Client Protocol Receiver Data transmitted by the server to the client come in four forms: command continuation requests, command completion results, intermediate responses, and untagged responses. A command completion request is prefixed with the token "+". A command completion result indicates the success or failure of the operation. It is tagged with the same tag as the client command which began the operation. Thus, if more than one command is in progress, the tag in a server completion response identifies the command to which the response applies. There are three possible server completion responses: OK (indicating success), NO (indicating failure), or BAD (indicating protocol error such as unrecognized command or command syntax error). An intermediate response returns data which can only be interpreted within the context of a command in progress. It is tagged with the same tag as the client command which began the operation. Thus, if more than one command is in progress, the tag in an intermediate Newman [Page 4]
Internet DRAFT ACAP March 21, 1997 response identifies the command to which the response applies. A tagged response other than "OK", "NO", or "BAD" is an intermediate response. An untagged response returns data or status messages which may be interpreted outside the context of a command in progress. It is prefixed with the token "*". Untagged data may be sent as a result of a client command, or may be sent unilaterally by the server. There is no syntactic difference between untagged data that resulted from a specific command and untagged data that were sent unilaterally. The protocol receiver of an ACAP client reads a response line from the server. It then takes action on the response based upon the first token of the response, which may be a tag, a "*", or a "+" as described above. A client MUST be prepared to accept any server response at all times. This includes untagged data that it may not have requested. This topic is discussed in greater detail in the Server Responses section. 2.3. State and Flow Diagram An ACAP server is in one of three states. Most commands are valid in only certain states. It is a protocol error for the client to attempt a command while the server is in an inappropriate state for that command. In this case, a server will respond with a BAD command completion result. 2.3.1. Non-Authenticated State In non-authenticated state, the user must supply authentication credentials before most commands will be permitted. This state is entered when a connection starts. 2.3.2. Authenticated State In authenticated state, the user is authenticated and most commands will be permitted. This state is entered when acceptable authentication credentials have been provided. Newman [Page 5]
Internet DRAFT ACAP March 21, 1997 2.3.3. Logout State In logout state, the session is being terminated, and the server will close the connection. This state can be entered as a result of a client request or by unilateral server decision. +--------------------------------------+ |initial connection and server greeting| +--------------------------------------+ || (1) || (2) VV || +-----------------+ || |non-authenticated| || +-----------------+ || || (4) || (3) || || VV || || +----------------+ || || | authenticated | || || +----------------+ || || || (4) || VV VV VV +--------------------------------------+ | logout and close connection | +--------------------------------------+ (1) connection (ACAP greeting) (2) rejected connection (BYE greeting) (3) successful LOGIN or AUTHENTICATE command (4) LOGOUT command, server shutdown, or connection closed 2.4. Operational Considerations 2.4.1. Untagged Status Updates At any time, a server can send data that the client did not request. 2.4.2. Response when no Command in Progress Server implementations are permitted to send an untagged response while there is no command in progress. Server implementations that send such responses MUST deal with flow control considerations. Specifically, they must either (1) verify that the size of the data does not exceed the underlying transport's available window size, or (2) use non-blocking writes. Newman [Page 6]
Internet DRAFT ACAP March 21, 1997 2.4.3. Autologout Timer If a server has an inactivity autologout timer, that timer MUST be of at least 30 minutes' duration. The receipt of ANY command from the client during that interval should suffice to reset the autologout timer. 2.4.4. Multiple Commands in Progress The client is not required to wait for the completion result of a command before sending another command, subject to flow control constraints on the underlying data stream. Similarly, a server is not required to process a command to completion before beginning processing of the next command, unless an ambiguity would result because of a command that would affect the results of other commands. If there is such an ambiguity, the server executes commands to completion in the order given by the client. 2.5. Datasets and Entries The primary data structure in ACAP is the "dataset", which is a named set of entries. Datasets are named hierarchically, with each component of the name being preceeded by a slash ("/") and containing one or more UTF-8 characters (other than slash). Each entry in a dataset is a set of attribute/value pairs. Each attribute is a hierarchical name in UTF-8, with each component of the name being separated with a period ("."). Each attribute/value pair may have additional metadata, this is described in section <section>. There must be exactly one "entry" attribute, whose value is unique amongst all entries in the dataset and contains zero or more UTF-8 characters other than slash ("/"). Entries in a dataset are ordered in a server-determined manner. The value of an attribute is a string containing one or more octets. The semantics of a value are defined by the specification of its attribute. Values of attributes ending in ".bin" contain arbitrary data. Values of other attributes are textual and are interpreted as a sequence of characters encoded in UTF-8. 2.6. Predefined Attributes Attribute names which do not contain a dot (".") are reserved for standardized attributes which have meaning in any dataset. The Newman [Page 7]
Internet DRAFT ACAP March 21, 1997 following attributes are defined by the ACAP protocol. entry Contains the name of the entry. modtime Contains the date and time, in UTC, any value or acl in the entry was last modified. This value is automatically updated by the server and may not be directly modified by the client. The value consists of 14 or more US-ASCII digits. The first four indicate the year, the next two indicate the month, the next two indicate the day of month, the next two indicate the hour (0 - 23), the next two indicate the minute, and the next two indicate the second. Any further digits indicate fractions of a second. The time, particularly fractions of a second, need not be accurate. It is required, however, that any two entries in a dataset changed by successive modifications have strictly ascending modtime values. createtime The modtime of the operation that created the entry. This is read-only. subdataset If this attribute is set, it indicates the existence of a sub-dataset of the current dataset whose final path component is the name of the entry. The value consists of a list of CRLF separated relative ACAP URLs (see section <section> for ACAP URL specification) which may be used to locate where the sub-dataset is actually stored. The base URL for the subdataset attribute is formed by appending the entry name followed by a "/" to the end of the parent dataset name. For example, if the dataset "/option/user" has an entry "john" with a subdataset attribute of ".", then there exists a dataset "/option/user/john". If the value of the subdataset attribute was instead "//;AUTH=*@other.acap.domain/option/user/john" that would indicate the dataset is actually located on a different ACAP server. A dataset is created by storing a "subdataset" attribute including ".", and a sub-hierarchy of datasets is deleted by clearing the value of the "subdataset" attribute on the entry Newman [Page 8]
Internet DRAFT ACAP March 21, 1997 in the upper dataset. 2.7. Attribute metadata Each attribute/value pair may have additional metadata associated with it. For completeness, the attribute and value themselves are defined as metadata. The defined items of metadata associated with an attribute/value pair are: attribute The attribute name. Read-only. value The value. value<ORIGIN.SIZE> A substring of the value. ORIGIN is specified as a non- negative decimal number indicating the octet position of the first desired octet. An ORIGIN of 0 specifies the first octet of the value. SIZE is specified as a positive, nonzero decimal number, specifying the maximum number of octets desired. Read-only. size The length of the value, in octets. Read-only. acl The access control list for the attribute/value pair, if one exists. If the attribute/value pair does not have an ACL, the null string. Read-write. See section <section> for the contents of an ACL. myrights The set of rights that the client has to the attribute/value pair. Read-only. See section <section> for the possible rights. Additional items of metadata may be defined in extensions to this protocol. Servers must respond to queries of unrecognized metadata by returning an error. 2.8. Operational Command Overview The AUTHENTICATE, LOGIN, NOOP, and LOGOUT commands provide basic protocol services. The SEARCH command is used to select, sort, fetch and monitor changes to attribute values and metadata. The UPDATECONTEXT and FREECONTEXT commands are also used to assist monitoring changes in attribute values and metadata. The STORE and DELETE commands are used to add, modify and delete entries and attributes. The DELETEDSINCE command is used to assist a client Newman [Page 9]
Internet DRAFT ACAP March 21, 1997 resynchronizing a cache with the server. The SETQUOTA, GETQUOTA, SETACL, DELETEACL and MYRIGHTS commands are used to examine or modifty quota usages and access permissions. 3. Protocol Elements This section defines data formats and other protocol elements used throughout the ACAP protocol. 3.1. Data Formats ACAP uses textual commands and responses. Data in ACAP can be in one of four forms: atom, number, string, or parenthesized list. 3.1.1. Atom An atom consists of one to 1024 non-special characters. 3.1.2. Number A number consists of one or more digit characters, and represents a numeric value. 3.1.3. String A string is in one of two forms: literal and quoted string. The literal form is the general form of string. The quoted string form is an alternative that avoids the overhead of processing a literal at the cost of restrictions of what may be in a quoted string. A literal is a sequence of zero or more octets (including CR and LF), prefix-quoted with an octet count in the form of an open brace ("{"), the number of octets, close brace ("}"), and CRLF. In the case of literals transmitted from server to client, the CRLF is immediately followed by the octet data. There are two forms of literals transmitted from client to server. The form where the open brace ("{") and number of octets is immediately followed by a close brace ("}") and CRLF is called a synchronizing literal. When sending a synchronizing literal, the client must wait to receive a command continuation request (described later in this document) before sending the octet data (and the remainder of the command). The other form of literal, the non- synchronizing literal, is used to transmit a string from client to server without waiting for a command continuation request. The non- Newman [Page 10]
Internet DRAFT ACAP March 21, 1997 synchronizing literal differs from the synchronizing literal by having a plus ("+") between the number of octets and the close brace ("}") and by having the octet data immediately following the CRLF. A quoted string is a sequence of zero to 1024 7-bit characters, excluding CR, LF, double quote (<">), or backslash ("\") with double quote (<">) characters at each end. The empty string is respresented as "" (a quoted string with zero characters between double quotes), as {0} followed by CRLF (a synchronizing literal with an octet count of 0), or as {0+} followed by a CRLF (a non-synchronizing literal with an octet count of 0). Note: Even if the octet count is 0, a client transmitting a synchronizing literal must wait to receive a command continuation request. 3.1.3.1. 8-bit and Binary Strings ACAP implementations MAY transmit 8-bit octets in literals. Except in the values of attributes whose names end with ".bin", these octets are interpreted as UTF-8 character sequences [UTF-8]. NUL octets are only permitted in the values of attributes whose names end with ".bin". Servers SHOULD verify any non-binary string sent by the client has valid UTF-8 syntax before storing it. 3.2. ACAP URL scheme ACAP URLs are used within the ACAP protocol for the "subdataset" attribute, referrals and inheritance. They provide a convenient syntax for referring to other ACAP datasets. The ACAP URL follows the common Internet scheme syntax as defined in [BASIC-URL]. If :<port> is omitted, the port defaults to 674. An ACAP URL has the following general form: url-acap ::= "acap://" url-server "/" url-enc-entry [url-filter] The <url-server> element (defined below) includes the hostname, and optional user name, authentication mechanism and port number. The <url-enc-entry> element contains the name of an entry path encoded according to the rules in [BASIC-URL]. The <url-filter> element is made up of up to three components. The first is a <url-attr-list> which specifies a list of interesting attributes (the default is all attributes). The second is <url- Newman [Page 11]
Internet DRAFT ACAP March 21, 1997 depth> which specifies the DEPTH of the search. Note that unsafe or reserved characters such as " " or "?" must be encoded according to the rules defined in [BASIC-URL]. Note that octets encoded in the %A0 format with the high bit set are interpreted according to UTF-8 [UTF8]. 3.2.1. ACAP URL User Name and Authentication Mechanism A user name and/or authentication mechanism may be supplied. They are used in the "LOGIN" or "AUTHENTICATE" commands after making the connection to the ACAP server. If no user name or authentication mechanism the user name "anonymous" is used with the "LOGIN" command and the password is supplied as the Internet e-mail address of the end user accessing the resource. If the URL supplies just a user name, the program interpreting the ACAP URL SHOULD request one from the user if necessary. An authentication mechanism can be expressed by adding ";AUTH=<enc_auth_type>" to the end of the user name. When such an <enc_auth_type> is indicated, the client SHOULD request appropriate credentials from that mechanism and use the "AUTHENTICATE" command instead of the "LOGIN" command. If no user name is specified, one SHOULD be obtained from the mechanism or requested from the user as appropriate. The string ";AUTH=*" indicates that the client SHOULD select an appropriate authentication mechanism. It MAY use any mechanism listed in the initial ACAP response. If no user name is specified and no appropriate authentication mechanisms are available, the client SHOULD fall back to anonymous login as described above. This allows a URL which grants read-write access to authorized users, and read-only anonymous access to other users. Note that if unsafe or reserved characters such as " " or ";" are present in the user name or authentication mechanism, they MUST be encoded as described in BASE-URL [BASE-URL]. 3.2.2. Relative ACAP URLs Because ACAP uses "/" as the hierarchy separator for dataset paths, it works well with the relative URL rules defined in REL-URL [REL- URL]. The <aauth> grammar element is considered part of the user name for purposes of resolving relative ACAP URLs. The base URL for a relative URL stored in an attribute's value is Newman [Page 12]
Internet DRAFT ACAP March 21, 1997 formed by taking the path to the dataset containing that attribute, appending a "/" followed by the entry name of the entry containing that attitude followed by "/". 3.3. Contexts A context is an ordered subset of entries in a dataset, created by a SEARCH command with a MAKECONTEXT modifier. Context names are client-generated strings and must not start with the slash ('/') character. Contexts only have scope within the ACAP session they were created. There is a server-imposed limit on the number of contexts that may exist at one time within a session. The minimum value for this limit is 100, if the server supports a larger limit it must advertise it in a CONTEXTLIMIT capability. 3.4. Orderings An ordering is a named collation function which takes two input strings and determines whether they are greater than, less than, or equal to each other. Orderings are used both for simple equality searching, for ordinal comparision searching and for sorting of attributes. An ordering is prefixed by either "+" or "-". If prefixed by "-", then the order is reversed. Additional ordering functions may be registered with IANA according to the rules in section <section>. The following ordering functions are defined by this standard: octet The octet ordering function interprets the value of an attribute as a series of unsigned octets with ordinal values from 0 to 255. The end of the string is interpreted as an ordinal value of -1. Each octet pair is compared in sequence until the octets are unequal or the end of the string is reached. The +octet form collates smaller ordinal values earlier, and the -octet form collates larger ordinal values earlier. For non-binary values, the +octet ordering is equivalent to the ANSI C strcmp() function applied to C string representations of the values. en-nocase The en-nocase ordering function first applies a mapping to the attribute values which translates all US-ASCII letters to uppercase (octet values 0x61 to 0x7A are translated to octet values 0x41 to 0x5A respectively), then applies the octet ordering function as described above. With this Newman [Page 13]
Internet DRAFT ACAP March 21, 1997 function the values "hello" and "HELLO" have the same ordinal value and are considered equal. numeric The numeric ordering function assigns ordinal values based on a US-ASCII encoded decimal positive integer interpretation. With the +numeric function, all values which do not begin with a digit are considered equal with an ordinal value of -1. Otherwise, all US-ASCII digits (octet values 0x30 to 0x39) are interpreted starting from the beginning of the string to the first non-digit or the end of the string. 3.5. Server Status Responses An OK, NO or BAD response from the server, whether tagged or untagged, is considered a status response. Status responses may include an optional response code. A response code consists of data inside square brackets in the form of an atom, possibly followed by a space and arguments. The response code contains additional information or status codes for client software beyond the OK/NO/BAD condition, and are defined when there is a specific action that a client can take based upon the additional information. The currently defined response codes are: ALERT The human-readable text contains a special alert that MUST be presented to the user in a fashion that calls the user's attention to the message. LOCKED The entry is already locked by another client. PERMISSION A STORE, SETQUOTA, SETACL or LOCK command failed due to insufficient permission. QUOTA A STORE command which would have increased the size of the dataset failed due to insufficient quota. REFER This response code may be returned in a tagged NO response to any command that takes a dataset name as a parameter. It is a referral, indicating that the command should be retried using one of the datasets named in the URL given in the argument. TOOMANY This response code may be returned in a tagged OK response to a SEARCH command which includes the LIMIT modifier. The argument returns the number of Newman [Page 14]
Internet DRAFT ACAP March 21, 1997 matching entries. TRYFREECONTEXT This response code may be returned in a tagged NO respose to a SEARCH command which includes the MAKECONTEXT modifier. It indicates that a new context may not be created due to the server's limit on the number of existing contexts. Additional response codes defined by particular client or server implementations should be prefixed with an "X" until they are added to a revision of this protocol. Client implementations MUST ignore response codes that they do not recognize. 3.6. Server Command Continuation Request The command continuation request is indicated by a "+" token instead of a tag. This indicates that the server is ready to accept the continuation of a command from the client. The remainder of this response is a line of text. This response is used in the AUTHENTICATE command to transmit server data to the client, and request additional client data. This response is also used if an argument to any command is a synchronizing literal. The client is not permitted to send the octets of a synchronizing literal unless the server indicates that it expects it. This permits the server to process commands and reject errors on a line-by-line basis, assuming it checks for non-synchronizing literals at the end of each line. The remainder of the command, including the CRLF that terminates a command, follows the octets of the literal. If there are any additional command arguments the literal octets are followed by a space and those arguments. Example: C: A001 LOGIN {11} S: + "Ready for additional command text" C: FRED FOOBAR {7} S: + "Ready for additional command text" C: fat man S: A001 OK "LOGIN completed" C: A044 BLURDYBLOOP {102856} S: A044 BAD "No such command as 'BLURDYBLOOP'" Newman [Page 15]
Internet DRAFT ACAP March 21, 1997 4. Protocol Specification ACAP commands and responses are described in this section. Commands are organized first by the state in which the command is permitted, then by a general category of command type. Command arguments, identified by "Arguments:" in the command descriptions below, are described by function, not by syntax. The precise syntax of command arguments is described in the Formal Syntax section. Some commands cause specific server data to be returned; these are identified by "Data:" in the command descriptions below. See the response descriptions in the Responses section for information on these responses, and the Formal Syntax section for the precise syntax of these responses. It is possible for server data to be transmitted as a result of any command; thus, commands that do not specifically require server data specify "no specific data for this command" instead of "none". The "Result:" in the command description refers to the possible tagged status responses to a command, and any special interpretation of these status responses. 4.1. Initial Connection Upon session startup, the server sends one of two untagged responses: ACAP or BYE. The untagged BYE response is described in section <section>. 4.1.1. ACAP Untagged Response Data: capability list The untagged ACAP response indicates the session is ready to accept commands and contains a space-separated listing of capabilities that the server supports. Each capability is an atom name, possibly followed by a string argument in parenthesis. ACAP capability names MUST be defined in a standards track or IESG approved experimental RFC and registered with IANA according to the rules in section <section>. Client implementations SHOULD NOT require any capability name, and MUST ignore any unknown capability names. Newman [Page 16]
Internet DRAFT ACAP March 21, 1997 The following initial capabilities are defined: CONTEXTLIMIT The CONTEXTLIMIT capability has one argument which is a number describing the maximum number of contexts the server supports per connection. This number MUST be greater than 100. IMPLEMENTATION The IMPLEMENTATION capability has one argument which is a string describing the server implementation. ACAP clients MUST NOT alter their behavior based on this value. It is intended primarily for debugging purposes. ORDERINGS The ORDERINGS capability includes a list of the ordering/comparison functions which the server supports. See section <section> for a description of ordering/comparison functions. SASL The SASL capability includes a list of the authentication mechanisms supported by the server. See [SASL] for more information. Example: S: * OK IMPLEMENTATION("ACME v3.5") SASL("CRAM-MD5" "GSSAPI") 4.2. Any State The following commands and responses are valid in any state. 4.2.1. NOOP Command Arguments: none Data: no specific data for this command (but see below) Result: OK - noop completed BAD - command unknown or arguments invalid The NOOP command always succeeds. It does nothing. Since any command can return a status update as untagged data, the NOOP command can be used as a periodic poll for status updates during a period of inactivity. The NOOP command can also be used Newman [Page 17]
Internet DRAFT ACAP March 21, 1997 to reset any inactivity autologout timer on the server. Example: C: a002 NOOP S: a002 OK "NOOP completed" 4.2.2. LOGOUT Command Arguments: none Data: mandatory untagged response: BYE Result: OK - logout completed BAD - command unknown or arguments invalid The LOGOUT command informs the server that the client is done with the session. The server must send a BYE untagged response before the (tagged) OK response, and then close the network connection. Example: C: A023 LOGOUT S: * BYE "ACAP Server logging out" S: A023 OK "LOGOUT completed" (Server and client then close the connection) 4.2.3. OK Response Data: optional response code human-readable text The OK response indicates an information message from the server. When tagged, it indicates successful completion of the associated command. The human-readable text may be presented to the user as an information message. The untagged form indicates an information-only message; the nature of the information may be indicated by a response code. Example: S: * OK [ALERT] "System shutdown in 10 minutes" 4.2.4. NO Response Data: optional response code human-readable text The NO response indicates an operational error message from the server. When tagged, it indicates unsuccessful completion of the associated command. The untagged form indicates a warning; the Newman [Page 18]
Internet DRAFT ACAP March 21, 1997 command may still complete successfully. The human-readable text describes the condition. Example: C: A001 LOGIN fred secret S: * NO [ALERT] "Dataset '/addressbook/user/fred' is at 98% of quota" S: A001 OK "LOGIN" ... C: A222 STORE "/mailboxes/comp.mail.misc" "mailbox.creation-time" "19951206103412" S: A222 NO "Permission denied" 4.2.5. BAD Response Data: optional response code human-readable text The BAD response indicates an error message from the server. When tagged, it reports a protocol-level error in the client's command; the tag indicates the command that caused the error. The untagged form indicates a protocol-level error for which the associated command can not be determined; it may also indicate an internal server failure. The human-readable text describes the condition. Example: C: ...empty line... S: * BAD "Empty command line" C: A443 BLURDYBLOOP S: A443 BAD "Unknown command" C: A444 NOOP Hello S: A444 BAD "invalid arguments" 4.2.6. BYE Untagged Response Data: optional response code human-readable text The untagged BYE response indicates that the server is about to close the connection. The human-readable text may be displayed to the user in a status report by the client. The BYE response may be sent as part of a normal logout sequence, or as a panic shutdown announcement by the server. It is also used by some server implementations as an announcement of an inactivity autologout. This response is also used as one of two possible greetings at session startup. It indicates that the server is not willing to Newman [Page 19]
Internet DRAFT ACAP March 21, 1997 accept a session from this client. Example: S: * BYE "Autologout; idle for too long" 4.3. Non-Authenticated State In non-authenticated state, the AUTHENTICATE or LOGIN command establishes authentication and enter authenticated state. The AUTHENTICATE command provides a general mechanism for a variety of authentication techniques, whereas the LOGIN command uses the traditional user name and plaintext password pair. Server implementations may allow non-authenticated access to certain information. The convention is to use a LOGIN command with the userid "anonymous". A password is required. It is implementation- dependent what requirements, if any, are placed on the password and what access restrictions are placed on anonymous users. Once authenticated (including as anonymous), it is not possible to re-enter non-authenticated state. In addition to the universal commands (NOOP and LOGOUT), the following commands are valid in non-authenticated state: AUTHENTICATE and LOGIN. 4.3.1. AUTHENTICATE Command Arguments: SASL mechanism name optional initial response Data: continuation data may be requested Result: OK - authenticate completed, now in authenticated state NO - authenticate failure: unsupported authentication mechanism, credentials rejected BAD - command unknown or arguments invalid, authentication exchange cancelled The AUTHENTICATE command indicates an authentication mechanism to the server. If the server supports the requested authentication mechanism, it performs an authentication protocol exchange to authenticate and identify the user. Optionally, it also negotiates a security layer for subsequent protocol interactions. If the requested authentication mechanism is not supported, the server rejects the AUTHENTICATE command by sending a tagged NO response. Newman [Page 20]
Internet DRAFT ACAP March 21, 1997 The authentication protocol exchange consists of a series of server challenges and client answers that are specific to the authentication mechanism. A server challenge consists of a command continuation request with the "+" token followed by a BASE64 encoded string. The client answer consists of a line consisting of a BASE64 encoded string. If the client wishes to cancel an authentication exchange, it should issue a line with a single "*". If the server receives such an answer, it must reject the AUTHENTICATE command by sending a tagged BAD response. The optional initial-response argument to the AUTHENTICATE command is used to save a round trip when using authentication mechanisms that are defined to send no data in the initial challenge. When the initial-response argument is used with such a mechanism, the initial empty challenge is not sent to the client and the server uses the data in the initial-response argument as if it were sent in response to the empty challenge. If the initial-response argument to the AUTHENTICATE command is used with a mechanism that sends data in the initial challenge, the server rejects the AUTHENTICATE command by sending a tagged NO response. The service name specified by this protocol's profile of SASL is "acap". If a security layer is negotiated through the SASL authentication exchange, it takes effect immediately following the CRLF that concludes the authentication exchange for the client, and the CRLF of the tagged OK response for the server. The server is not required to support any particular authentication mechanism, nor are authentication mechanisms required to support any protection mechanisms. If an AUTHENTICATE command fails with a NO response, the client may try another authentication mechanism by issuing another AUTHENTICATE command, or may attempt to authenticate by using the LOGIN command. In other words, the client may request authentication types in decreasing order of preference, with the LOGIN command as a last Newman [Page 21]
Internet DRAFT ACAP March 21, 1997 resort. Example: S: * OK IMPLEMENTATION("Blorfysoft v3.5") SASL(KERBEROS_V4) C: A001 AUTHENTICATE KERBEROS_V4 S: + AmFYig== C: BAcAQU5EUkVXLkNNVS5FRFUAOCAsho84kLN3/IJmrMG+25a4DT +nZImJjnTNHJUtxAA+o0KPKfHEcAFs9a3CL5Oebe/ydHJUwYFd WwuQ1MWiy6IesKvjL5rL9WjXUb9MwT9bpObYLGOKi1Qh S: + or//EoAADZI= C: DiAF5A4gA+oOIALuBkAAmw== S: A001 OK "Kerberos V4 authentication successful" Note: the line breaks in the first client answer are for editorial clarity and are not in real authenticators. 4.3.2. LOGIN Command Arguments: user name password Data: no specific data for this command Result: OK - login completed, now in authenticated state NO - login failure: user name or password rejected BAD - command unknown or arguments invalid The LOGIN command identifies the user to the server and carries the plaintext password authenticating this user. Example: C: a001 LOGIN SMITH SESAME S: a001 OK "LOGIN completed" 4.4. Searching This section describes the SEARCH command, for retrieving data from datasets. Newman [Page 22]
Internet DRAFT ACAP March 21, 1997 4.4.1. SEARCH Command Arguments: dataset or context name optional list of modifiers search criteria Data: intermediate responses: ENTRY, MODTIME untagged responses: ADDTO, REMOVEFROM, CHANGE, MODTIME Result: OK - search completed NO - search failure: can't perform search BAD - command unknown or arguments invalid The SEARCH command identifies a subset of entries in a dataset and returns information on that subset to the client. The first argument to SEARCH identifies what is to be searched. If the string begins with a slash ("/"), it is the name of a dataset to be searched, otherwise it is a name of a context that was created by a SEARCH command given previously in the session. Following that are zero or more modifiers to the search. Each modifier may be specified at most once. The defined modifiers are: DEPTH number The SEARCH command will traverse the dataset tree up to the specified depth. ENTRY responses will include the full path to the entry. This MUST NOT be combined with a SORT or MAKECONTEXT operator. LIMIT number number Limits the number of intermediate ENTRY responses that the search may generate. The first numeric argument specifies the limit, the second number specifies the number of entries to return if the number of matches exceeds the limit. If the limit is exceeded, the SEARCH command still succeeds, returning the number of matches in a TOOMANY special information token in the tagged OK response. MAKECONTEXT context The SEARCH command creates a context with the name given in the argument to refer to the matching entries. If the SEARCH is successful, the context name may then be given as an argument to subsequent SEARCH Newman [Page 23]
Internet DRAFT ACAP March 21, 1997 commands to search the set of matching entries. If a context with the specified name already exists, it is first freed. If a new context may not be created due to the server's limit on the number of existing contexts, the command fails, returning a TOOMANYCONTEXTS special information token in the tagged NO response. Contexts are discussed in more detail in section <section>. NOTIFYCONTEXT Requests that the server send untagged ADDTO, REMOVEFROM, CHANGE, and MODTIME responses while the context created or referenced by this SEARCH command exists. The server MAY issue untagged ADDTO, REMOVEFROM, CHANGE and MODTIME notifications for a context at any time between the issuing of the SEARCH command with NOTIFYCONTEXT and the completion of a FREECONTEXT command for the context. After issuing a sequence of ADDTO, REMOVEFROM or CHANGE notifications, the server MUST issue an untagged MODTIME notification indicating that the client has all updates to the entries in the context up to and including the given modtime value. The client MAY issue a subsequent SEARCH on the context with a NOTIFYCONTEXT modifier, and this MAY be used to change the list of attributes and metadata included in ADDTO and CHANGE responses for the context. RETURN (metadata...) Specifies what is to be returned in intermediate ENTRY responses. If this modifier is not specified, no intermediate ENTRY responses are returned. Inside the parenthesis is a list of attributes, each optionally followed by a parenthesized list of metadata. If the parenthesized list of metadata is not specified, it defaults to "(value)". An attribute name with a trailing "*" requests all attributes with that prefix. A "*" by itself requests all attributes. If the parenthesized list of metadata is not specified with an attribute with Newman [Page 24]
Internet DRAFT ACAP March 21, 1997 a trailing "*", it defaults to "(attribute value)". Following the last intermediate ENTRY response, the server returns a single intermediate MODTIME response. SORT (attribute ordering...) Specifies the order in which any resulting ENTRY replies are to be returned to the client. The SORT modifier takes as an argument a parenthesized list of one or more attribute/ordering pairs. Attribute lists the attribute to sort on, ordering specifies the name of the collation rule to apply to the values of the attribute. Successive attribute/ordering pairs are used to apply ordering of two entries only when all preceeding pairs indicate two entries collate the same. If the SORT modifier is used in conjunction with the MAKECONTEXT modifier, the SORT modifier specifies the ordering of entries in the created context. If no SORT modifier is specified, or none of the attribute/ordering pairs indicates an order to two entries, the server uses the order of the entries that exists in the context or dataset being searched. Following the modifiers is the search criteria. Searching criteria consist of one or more search keys. Search keys may be combined using the AND, and OR search keys. For example, the criteria (the newline is for readability and not part of the criteria): AND COMPARE modtime +octet "19951206103400" COMPARE modtime -octet "19960112000000" refers to all entries modified between 10:34 December 6 1995 and midnight January 12, 1996 UTC. The currently defined search keys are as follows. AND search-key1 search-key2 Entries that match both search keys. COMPARE attribute ordering value Entries for which the specified attribute collates using the specified ordering the same or later than the specified Newman [Page 25]
Internet DRAFT ACAP March 21, 1997 value. COMPARESTRICT attribute ordering value Entries for which the specified attribute collates using the specified ordering later than the specified value. EQUAL attribute ordering value Entries for which the specified attribute collates using the specified ordering the same as the specified value. NOT search-key Entries that do not match the specified search key. OR search-key1 search-key2 Entries that match either search key. RANGE start end Entries which are within the specified range of the dataset or context's ordering. The lowest-ordered entry in the dataset or context is assigned number one, the next lowest entry is assigned number two, and so on. The numeric arguments specify the lowest and highest numbers to match. Example: C: [TODO - write examples] 4.4.2. ENTRY Intermediate Response Data: entry name entry data The ENTRY intermediate response occurs as a result of a SEARCH or LOCK command. This is the means by which dataset entries are returned to the client. The entry with the given name matches the search. Following the entry name is a set of zero or more strings, each containing the respective metadata, contained in the entry, that was specified in the RETURN search modifier. 4.4.3. MODTIME Intermediate Response Data: modtime value The MODTIME intermediate response occurs as a result of a SEARCH command. It indicates that the previously returned ENTRY responses include all updates to the returned entries up to and including the modtime value in the argument. Newman [Page 26]
Internet DRAFT ACAP March 21, 1997 4.5. Contexts The following commands use contexts created by a SEARCH command with a MAKECONTEXT modifier. 4.5.1. FREECONTEXT Command Arguments: context name Data: no specific data for this command Result: OK - freecontext completed NO - freecontext failure: no such context BAD - command unknown or arguments invalid The FREECONTEXT command causes the server to free all state associated with the named context. The context may no longer be searched and the server will no longer issue any untagged responses for the context. The context is no longer counted against the server's limit on the number of contexts. Example: C: A683 FREECONTEXT "blurdybloop" S: A683 OK "Freecontext completed" 4.5.2. UPDATECONTEXT Command Arguments: list of context names Data: untagged responses: ADDTO REMOVEFROM CHANGE MODTIME Result: OK - Updatecontext completed: all updates completed NO - Updatecontext failed: no such context BAD - command unknown or arguments invalid The UPDATECONTEXT command causes the server to ensure that the client is notified of all changes to the contexts listed as arguments up to the current time. The contexts listed in the arguments must have been previously given to a successful NOTIFYCONTEXT command. While a server may issue untagged ADDTO, REMOVEFROM, CHANGE, and MODTIME at any time, the UPDATECONTEXT command is used to "prod" the server to send any notifications it has not sent yet. The UPDATECONTEXT command SHOULD NOT be used to poll for updates. Newman [Page 27]
Internet DRAFT ACAP March 21, 1997 Example: C: Z4S9 UPDATECONTEXT "blurdybloop" "blarfl" S: Z4S9 OK "client has been notified of all changes" 4.5.3. ADDTO Untagged Response Data: context name entry name position metadata list The untagged ADDTO response informs the client that an entry has been added to a context. The response includes the position number of the added entry (the first entry in the context is numbered 1) and those metadat contained in the entry which match the RETURN statement specified in the last SEARCH command on the context with NOTIFYCONTEXT. Example: S: * ADDTO "blurdybloop" "fred" 15 ("addressbook.email" "fred@rock.org") 4.5.4. REMOVEFROM Untagged Response Data: context name entry name old position The untagged REMOVEFROM response informs the client that an entry has been removed from a context. The response includes the position number that the removed entry used to have (the first entry in the context is numbered 1). Example: S: * REMOVEFROM "blurdybloop" "fred" 15 4.5.5. CHANGE Untagged Response Data: context name entry name old position new position metadata list The untagged CHANGE response informs the client that an entry in a context has either changed position in the context or has changed the values of one or more of the attributes specified in the last NOTIFYCONTEXT command for the context. Newman [Page 28]
Internet DRAFT ACAP March 21, 1997 The response includes the previous and current position numbers of the entry (the first entry in the context is numbered 1) and those attribute/value pairs contained in the entry which match attributes specified in the last NOTIFYCONTEXT command for the context. Example: S: * CHANGE "blurdybloop" "fred" 15 10 ("addressbook.email" "fred@stone.org") 4.5.6. MODTIME Untagged Response Data: context name modtime value The untagged MODTIME response informs the client that it has recieved all updates to entries in the context which have modtime values less than or equal to the modtime value in the argument. Example: S: * MODTIME mycontext "19970320162338" 4.6. Dataset modification The following commands and responses handle modification of datasets. 4.6.1. STORE Command Arguments: entry path attribute/value list Data: no specific data for this command Result: OK - store completed NO - store failure: can't store that name invalid UTF-8 syntax BAD - command unknown or arguments invalid Creates or modifies the named entry in the named dataset. The values of metadata not specified in the command are not changed. Setting the "value" metadata of an attribute to the empty string removes the attribute from the entry. The reserved attribute "entry" may be included in the metadata list. Changing the value of this attribute indicates a request to rename the entry. The reserved attribute "modtime" may not be included in the metadata list, but will automatically be updated. The reserved Newman [Page 29]
Internet DRAFT ACAP March 21, 1997 attribute "createtime" may not be included in the metadata list, but will automatically be set when an entry is created. Example: C: A342 STORE "/addressbook/user/fred/Barney Rubble" "addressbook.phone" "555-1234" "addressbook.email" "" S: A342 OK "Store completed" 4.6.2. DELETE Command Arguments: entry path Data: no specific data for this command Result: OK - delete completed NO - delete failure: can't delete that entry BAD - command unknown or arguments invalid Removes the named entry. If there is no such entry, the command simply returns a tagged OK response. Example: C: A344 DELETE "/addressbook/user/fred/Dino" S: A344 OK "Delete completed" C: A345 DELETE "/addressbook/user/fred/Dino" S: A345 OK "Entry doesn't exist" 4.6.3. DELETEDSINCE Command Arguments: dataset name time Data: intermediate response: DELETED Result: OK - DELETED completed NO - DELETED failure: can't read dataset date too far in the past BAD - command unknown or arguments invalid The DELETEDSINCE command returns in intermediate DELETED replies the names of entries that have been deleted from the named dataset since the given time. Servers may impose a limit on the number or age of deleted entry names they keep track of. If the server does not have information going back to the specified time, the command fails, returning a Newman [Page 30]
Internet DRAFT ACAP March 21, 1997 TOOOLD special information token in the tagged NO response. Example: C: Z4S9 DELETEDSINCE "/mailboxes/common" 19951205103412 S: Z4S9 DELETED "blurdybloop" S: Z4S9 DELETED "anteaters" S: Z4S9 OK "DELETEDSINCE completed" C: Z4U3 DELETEDSINCE "/mailboxes/common" 19951009040854 S: Z4U3 NO [TOOOLD] "Don't have that information" 4.6.4. DELETED Intermediate Response Data: entry name The untagged DELETED response occurs as a result of a DELETEDSINCE command. It returns an entry that has been deleted from the dataset specified in the DELETEDSINCE command. Example: S: Z4S9 DELETED "blurdybloop" 4.7. Access Control Lists An access control list is a tab-separated set of identifier,rights pairs. Identifier is a US-ASCII string. The identifier anyone is reserved to refer to the universal identity (all authentications, including anonymous). All user name strings accepted by the LOGIN or AUTHENTICATE commands to authenticate to the ACAP server are reserved as identifiers for the corresponding user. Identifiers starting with a dash ("-") are reserved for "negative rights", described below. All other identifier strings have implementation-defined semantics. Rights is a string listing a (possibly empty) set of alphanumeric characters, each character listing a set of operations which is being controlled. Letters are reserved for ``standard'' rights, listed below. The set of standard rights may only be extended by a standards-track document. Digits are reserved for implementation or site defined rights. The currently defined standard rights are: r - read w - write i - insert (store a new value) o - override (see section <section>) a - administer (perform store on ACL attribute/metadata) An implementation may force rights to always or never be granted. Rights are never tied, unlike the IMAP ACL extension [IMAP-ACL]. Newman [Page 31]
Internet DRAFT ACAP March 21, 1997 It is possible for multiple identifiers in an access control list to apply to a given user (or other authentication identity). For example, an ACL may include rights to be granted to the identifier matching the user, one or more implementation-defined identifiers matching groups which include the user, and/or the identifier "anyone". How these rights are combined to determine the user's access is implementation-defined. An implementation may choose, for example, to use the union of the rights granted to the applicable identifiers. An implementation may instead choose, for example, to only use those rights granted to the most specific identifier present in the ACL. A client may determine the set of rights granted to the logged-in user for a given mailbox by using the MYRIGHTS command. When an identifier in an ACL starts with a dash ("-"), that indicates that associated rights are to be removed from the identifier that is prefixed by the dash. For example, if the identifier "-fred" is granted the "w" right, that indicates that the "w" right is to be removed from users matching the identifier "fred". Implementations need not support having identifiers which start with a dash in ACLs. Each attribute of each entry of a dataset may potentially have an ACL. If an attribute in an entry does not have an ACL, then access is controlled by a default ACL for that attribute in the dataset, if it exists. If there is no default ACL for that attribute in the dataset, access is controlled by a default ACL for that dataset. The default ACL for a dataset must exist. In order to perform any manipulation on an entry on a dataset, the client must have 'r' rights on the "entry" attribute of the entry. Implementations should take care not to reveal via error messages the existence of an entry for which the client does not have 'r' rights. A client does not need access to the "subdataset" attribute of the parent dataset in order to access the contents of a dataset. Many of the ACL commands and responses include an ``acl object'' parameter, for specifying what the ACL applies to. This is a parenthesized list. The list contains just the dataset name when referring to the default ACL for a dataset. The list contains a dataset name and an attribute name when referring to the default ACL for an attribute in a dataset. The list contains a dataset name, an attribute name, and an entry name when referring to the ACL for an attribute of an entry of a dataset. Newman [Page 32]
Internet DRAFT ACAP March 21, 1997 4.7.1. SETACL Command Arguments: acl object authentication identifier access rights Data: no specific data for this command Result: OK - setacl completed NO - setacl failure: can't set acl BAD - command unknown or arguments invalid The SETACL command changes the access control list on the specified object so that the specified identifier is granted the permissions enumerated in rights. If the object did not previously have an access control list, one is created. Example: C: A123 SETACL ("/addressbook/user/joe/public") anyone r S: A123 OK "Setacl complete" C: A124 SETACL ("/mailboxes/common") B1FF rwa S: A124 NO [PERMISSION] "'B1FF' not permitted to modify access rights for '/mailboxes/common'" 4.7.2. DELETEACL Command Arguments: acl object optional authentication identifier Data: no specific data for this command Result: OK - deleteacl completed NO - deleteacl failure: can't delete acl BAD - command unknown or arguments invalid If given the optional identifier argument, the DELETEACL command removes any portion of the access control list on the specified object for the specified identifier. If not given the optional identifier argument, the DELETEACL command removes the ACL from the object entirely, causing access to be controlled by a higher-level default ACL. It is an error to use this form of the DELETEACL command on the default ACL for a dataset. Newman [Page 33]
Internet DRAFT ACAP March 21, 1997 Example: C: A223 DELTEACL ("/addressbook/user/joe/public") anyone S: A223 OK "Deleteacl complete" C: A224 DELETEACL ("/mailboxes/common") S: A224 NO "Can't delete top-level acl for dataset" C: A225 DELETEACL ("/addressbook/user/fred" "addressbook.email" "barney") S: A225 OK "Deleteacl complete" 4.7.3. MYRIGHTS Command Arguments: acl object Data: intermediate responses: MYRIGHTS Result: OK - myrights completed NO - myrights failure: can't get rights BAD - command unknown or arguments invalid The MYRIGHTS command returns the set of rights that the client has to the given dataset or dataset attribute in an intermediate MYRIGHTS reply. Example: C: A003 MYRIGHTS ("/mailboxes/common") S: A003 MYRIGHTS "r" "" S: A003 OK "Myrights complete" C: A004 MYRIGHTS ("/user/joe/mailboxes" "mailbox.subscribe") S: A004 MYRIGHTS "rwa" "ra" S: A004 OK "Myrights complete" 4.7.4. MYRIGHTS Intermediate Response Data: rights implicit rights The MYRIGHTS response occurs as a result of a MYRIGHTS command. The first argument is the set of rights that the client has for the object referred to in the MYRIGHTS command. The second argument is the set of implicit rights the client has for the object regardless of what the ACL contains. Newman [Page 34]
Internet DRAFT ACAP March 21, 1997 4.8. Quotas Quotas are used to manage storage consumed by ACAP datasets. A quota root is a place where a resource limit may be set which applies to an implementation dependant subset of datasets. 4.8.1. SETQUOTA Command Arguments: quota root resource limit in kilobytes Data: intermediate responses: QUOTA Result: OK - Quota root resource limit modified NO - Quota failure: can't modify resourse limit BAD - command unknown or arguments invalid The SETQUOTA command takes the name of a quota root and a number indicating the desired resource limit in kilobytes on all datasets within that root. A value of "0" indicates no resource limit is desired. If the named quota root did not previously exist and a value other than "0" is specified, an implementation SHOULD create it. If the quota root exists and a value of "0" is specified, an implementation SHOULD delete the quota root. In either case the implementation may change the quota root which applies to any number of datasets. Example: C: A042 SETQUOTA "/user/fred" 1024 S: A042 QUOTA "/user/fred" 1024 0 S: A042 OK "Setquota completed" 4.8.2. GETQUOTA Command Arguments: dataset Data: intermediate responses: QUOTA Result: OK - Quota information returned NO - Quota failure: can't access resourse limit BAD - command unknown or arguments invalid The GETQUOTA command takes the name of a dataset, and returns in an intermediate QUOTA response the name of the quota root, the Newman [Page 35]
Internet DRAFT ACAP March 21, 1997 amount of the resource limit on that root and the amount of that resource limit which is used. Example: C: A043 GETQUOTA "/option/user/fred/common" S: A043 QUOTA "/user/fred" 1024 50 S: A043 OK "Getquota completed" 4.8.3. QUOTA Intermediate Response Data: quota root resource limit in kilobytes amount of resource limit used The QUOTA intermediate response is generated as a result of a SETQUOTA or GETQUOTA command. It includes the name of the quota root, the resource limit in kilobytes and the amount of resource limit used. 4.9. Advisory locking These commands allow cooperating clients to synchronize their updates to datasets. 4.9.1. LOCK Command Arguments: dataset name list of entry names optional list of metadata to return Data: intermediate responses: ENTRY, MODTIME Result: OK - lock completed NO - lock failure: can't lock dataset/entry some other client has obtained lock on dataset/entry BAD - command unknown or arguments invalid The LOCK command accepts as arguments a dataset name and an optional list of entry names. It attempts to acquire an exclusive semaphore on each of the entries in the dataset. The dataset must exist, but the named entries need not. If the command is successful, the server must ensure that no other client will be able to successfully lock any of the named entries in the dataset until the successful client either performs a Newman [Page 36]
Internet DRAFT ACAP March 21, 1997 matching UNLOCK command or closes the connection. If some other client has obtained a semaphore on one of the named entries, the command fails, returning a LOCKED special information token in the tagged NO response. If the command is successful and the optional list of attributes and metadata is present, the server returns the appropriate data in intermediate ENTRY responses. The server should ensure that the client has permission to perform a STORE operation on at least one attribute of each of the entries. Even though other clients may not perform a LOCK operation on an entry, servers should not prevent them from performing STORE operations on the entry. Example: C: A069 LOCK "/addressbook/fred" ("barney") ("addressbook.email") S: A069 ENTRY "barney" "addressbook.email" "barney@bedrock" S: A069 MODTIME "19970320162338" S: A069 OK "Lock completed" C: A070 LOCK "/addressbook/common" ("Bam Bam") S: A070 NO [LOCKED] "Locked by Barney on client7.do.main" 4.9.2. UNLOCK Command Arguments: dataset name list of entry names Data: no specific data for this command Result: OK - unlock completed NO - unlock failure: can't unlock that dataset/entry BAD - command unknown or arguments invalid The UNLOCK command accepts as arguments a dataset name and a list of entry names. It releases any semaphores the client may have previously obtained on those entries by using the LOCK command. If the client did not have a lock on one of the entries, the command succeeds anyway. Newman [Page 37]
Internet DRAFT ACAP March 21, 1997 4.10. Extensions In order to simplify the process of extending the protocol, clients MUST ignore unknown server responses which meet the syntax of response-extend. In addition, clients MUST ignore server response codes which meet the syntax of resp-code-ext. Availability of new commands MUST be announced via a capability on the initial greeting line and such commands SHOULD meet the syntax of command-extend. Newman [Page 38]
Internet DRAFT ACAP March 21, 1997 5. Dataset Management The entry with an empty name in the dataset is used to hold management information for the dataset as a whole. 5.1. Dataset Inheritance It is possible for a dataset to inherit data from another. Data in the inherited dataset appears in the inheriting dataset, except where explicitly overridden by data in the inheriting dataset. The inherited dataset specifies which values may be overridden in the inheriting datasets. If an inherited dataset has a non-empty value for any given attribute in an entry, the ACL for that attribute in that entry must grant a user the 'o' right in order for the user to store a corresponding value in an inheriting dataset. The inherited dataset is usually a system-wide or group-wide set of defaults. The system-wide dataset usually has one inheriting dataset per user, allowing each user to add to or modify the defaults as appropriate. Servers MUST support at least two levels of inheritance. This permits a user's dataset such as "/options/user/fred/common" to inherit from a group dataset such as "/options/group/dinosaur operators/common" which in turn inherits from a server-wide dataset such as "/options/common/common". 5.2. Dataset attributes The following attributes apply to management of the dataset when stored in the "" entry of a dataset. dataset.acl This holds the default access control list for the dataset. It can not be modified by the STORE command, only by the SETACL and DELETEACL commands. dataset.acl.<attribute> This holds the default access control list for an attribute within the dataset. It can not be modified by the STORE command, only by the SETACL and DELETEACL commands. dataset.inherit This holds the name of a dataset to inherit according to the Newman [Page 39]
Internet DRAFT ACAP March 21, 1997 rules in section <section>. dataset.sort-hint.<attribute> This contains a space separated list of ordering functions. An implementation MAY use it as a hint that a SORT modifier with the specified ordering function for the given attribute is likely to be used. For example, an implementation might wish to index those attributes which have a sort hint. Implementations are free to ignore this field. 6. Namespace conventions 6.1. Dataset Namespace The dataset namespace is a slash-separated hierarchy. By convention, the first component of the dataset namespace is a dataset class. A dataset class SHOULD be published as an RFC which includes predefined set of attributes and their meanings. The second component of the dataset name is "common", "group", or "user" for server-wide, group- wide, or per-user datasets respectively. For group or user datasets, the third component of the dataset name is the name of the group or the LOGIN/AUTHENTICATE identifier for the user. Other components of the dataset name are specific to the dataset class. Dataset classes MUST be registered with IANA according to the rules in section <section>. Dataset classes which are intended for interoperable use MUST be published as a standards track or IESG approved experimental RFC. 6.2. Attribute Namespace Attribute names which do not contain a dot (".") are reserved for standardized attributes which have meaning in any dataset. In order to simplify implementations, the attribute namespace is intended to be unique across all datasets. To achieve this, attribute names are prefixed with the dataset class name followed by a dot ("."). Attributes which effect management of the dataset are prefixed with "dataset.". In addition, a subtree of the "private." namespace may be registered with IANA according to the rules in section <section>. ACAP implementors are encouraged to help define interoperable dataset classes rather than using the private attribute namespace. 7. Registration procedures ACAP's usefulness comes from providing a structured storage model for all sorts of configuration data. However, for its potential to be Newman [Page 40]
Internet DRAFT ACAP March 21, 1997 achieved, it is important that the Internet community strives for the following goals: (1) Standardization. It is very important to standardize dataset classes. The authors hope that ACAP achieves the success that SNMP has seen with the definition of numerous standards track MIBs. (2) Community Review. In the absence of standardization, it is important to get community review on a proposal to improve the engineering quality. Community review is strongly recommended prior to registration. The ACAP developers mailing list <ietf- acap@andrew.cmu.edu> may be used for this purpose. (3) Registration. Registration serves a two-fold purpose. First it prevents use of the same name for different purposes, and second it provides a one-stop list which can be used to locate existing extensions. The following registration templates may be used to register ACAP protocol elements. 7.1. Ordering Functions Additional ordering functions may be registered with IANA on a first-come, first-serve basis. Ordering functions intended for interoperable use SHOULD be defined as a standards track or IESG approved experimental RFC. To: XXX@XXX.XXX Subject: Registration of new ACAP ordering function Ordering name: Scope: Any Dataset / Specific Dataset class / Specific locality Published Specification(s): (If the published specification is not standards track, or no published specifiction is referenced then the ordering function is assumed to be for limited use) Person and email address to contact for further information: 7.2. ACAP Capabilities New ACAP capabilities MUST be standards track or IESG approved experimental RFCs. Registration provides a simple way to locate all extensions. Careful consideration should be made before extending Newman [Page 41]
Internet DRAFT ACAP March 21, 1997 the protocol, as it can lead to complexity or interoperability problems. To: XXX@XXX.XXX Subject: Registration of ACAP capability Capability name: Capability keyword: Capability arguments: standards track/IESG-approved experimental RFC number: 7.3. Dataset Classes A dataset class provides a core set of attributes for use in a specified hierarchy. It may also define rules for the dataset hierarchy underneath that class. Community review of dataset classes is strongly encouraged. Classes intended for interoperable use should be written as standards track or IESG approved experimental RFCs. To: XXX@XXX.XXX Subject: Registration of ACAP dataset class Dataset class name/attribute prefix: Purpose: Required attributes: Optional attributes: Published Specification(s): (The published specification must be freely available on the Internet or included with the registration. It should include ABNF [as defined in RFC 822] for the specified attributes.) Person and email address to contact for further information: 7.4. Private Attribute Subtree A private attribute subtree may be registered on a first come, first serve basis. Private attributes may be used to store information specific to a particular client within an ACAP entry of any dataset class. Whenever possible, private attributes should be avoided in Newman [Page 42]
Internet DRAFT ACAP March 21, 1997 favor of improving interoperable dataset class definitions. To: XXX@XXX.XXX Subject: Registration of ACAP private prefix Private Prefix: private. Person and email address to contact for further information: (company names and addresses should be included when appropriate) 8. Formal Syntax The following syntax specification uses the augmented Backus-Naur Form (BNF) notation as specified in [IMAIL] with one exception; the delimiter used with the "#" construct is a single space (SPACE) and not one or more commas. Except as noted otherwise, 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. ALPHA ::= "A" / "B" / "C" / "D" / "E" / "F" / "G" / "H" / "I" / "J" / "K" / "L" / "M" / "N" / "O" / "P" / "Q" / "R" / "S" / "T" / "U" / "V" / "W" / "X" / "Y" / "Z" / "a" / "b" / "c" / "d" / "e" / "f" / "g" / "h" / "i" / "j" / "k" / "l" / "m" / "n" / "o" / "p" / "q" / "r" / "s" / "t" / "u" / "v" / "w" / "x" / "y" / "z" / ;; Case-sensitive ATOM-CHAR ::= <any CHAR except ATOM-SPECIALS> ATOM-SPECIALS ::= "(" / ")" / "{" / "[" / "]" / SPACE / CTL / QUOTED-SPECIALS BASE64-CHAR ::= ALPHA / DIGIT / "+" / "/" CHAR ::= <any 7-bit US-ASCII character except NUL, 0x01 - 0x7f> CHAR8 ::= <any 8-bit octet except NUL, 0x01 - 0xff> CR ::= <ASCII CR, carriage return, 0x0C> CRLF ::= CR LF CTL ::= <any ASCII control character and DEL, 0x00-0x1f, 0x7f> Newman [Page 43]
Internet DRAFT ACAP March 21, 1997 DIGIT ::= "0" / DIGIT-NZ DIGIT-NZ ::= "1" / "2" / "3" / "4" / "5" / "6" / "7" / "8" / "9" LF ::= <ASCII LF, line feed, 0x0A> OCTET ::= <any octet value 0x00 - 0xFF> QUOTED-CHAR ::= <any TEXT-UTF8-CHAR except QUOTED-SPECIALS> / "\" QUOTED-SPECIALS QUOTED-SPECIALS ::= <"> / "\" SPACE ::= <ASCII SP, space, 0x20> TEXT-CHAR ::= <any CHAR except CR and LF> TEXT-UTF8-CHAR ::= <any UTF8-CHAR except CR and LF> UTF8-CHAR ::= <TODO: UTF-8 character> acl-identifier ::= string acl-object ::= "(" dataset [SPACE attribute [SPACE entry-name]] ")" acl-rights ::= quoted astring ::= atom / string atom ::= 1*ATOM-CHAR attribute ::= string ;; dot-separated attribute name ;; ends in ".bin" if value not textual auth-type ::= atom ;; as defined in SASL [SASL] base64-token ::= *(4BASE64-CHAR) [base64-terminal] base64-terminal ::= (2BASE64-CHAR "==") / (3BASE64-CHAR "=") command ::= tag SPACE (command-any / command-auth / command-nonauth) CRLF ;; Modal based on state command-login ::= "LOGIN" SPACE astring SPACE astring Newman [Page 44]
Internet DRAFT ACAP March 21, 1997 command-authent ::= "AUTHENTICATE" SPACE atom [SPACE base64-token] *(CRLF base64-token) command-any ::= "NOOP" command-auth ::= command-delacl / command-delete / command-dsince / command-freectx / command-getquota / command-lock / command-myrights / command-search / command-setacl / command-setquota / command-store / command-unlock ;; only valid in authenticaticated state command-delacl ::= "DELETEACL" SPACE acl-object [SPACE acl-identifier] command-delete ::= "DELETE" SPACE entry-path command-dsince ::= "DELETEDSINCE" SPACE dataset SPACE time command-extend ::= atom [SPACE #extension-data] command-freectx ::= "FREECONTEXT" SPACE context command-getquota ::= "GETQUOTA" SPACE dataset command-lock ::= "LOCK" SPACE dataset SPACE "(" 1#entry-name ")" [ SPACE "(" #metadata ")" ] command-myrights ::= "MYRIGHTS" SPACE acl-object command-nonauth ::= command-login / command-authent ;; only valid in non-authenticated state command-search ::= "SEARCH" SPACE (dataset / context) *(SPACE search-modifier) SPACE search-criteria command-setacl ::= "SETACL" SPACE acl-object SPACE acl-identifier SPACE acl-rights command-setquota ::= "SETQUOTA" SPACE quota-root SPACE number command-store ::= "STORE" SPACE entry-path 1*(SPACE attribute SPACE value) command-unlock ::= "UNLOCK" SPACE dataset SPACE "(" 1#entry-name ")" context ::= string ;; MUST NOT begin with slash ("/") Newman [Page 45]
Internet DRAFT ACAP March 21, 1997 continue-req ::= "+" SPACE (resp-text / base64-token) dataset ::= string ;; slash-separated dataset name ;; begins with slash entry ::= entry-name / entry-path entry-name ::= string ;; entry name MUST NOT contain slash entry-path ::= string ;; slash-separated path to entry ;; begins with slash entry-relative ::= string ;; potentially relative path to entry extension-data ::= string / number / "(" #extension-data ")" initial-greeting ::= "*" SPACE "ACAP" *(SPACE init-capability) CRLF init-capability ::= atom [ "(" string ")" ] literal ::= "{" number [ "+" ] "}" CRLF *OCTET ;; The number represents the number of octets ;; MUST be literal-utf8 except for values of ;; attributes whose names end in ".bin" literal-utf8 ::= "{" number [ "+" ] "}" CRLF *UTF8-CHAR ;; The number represents the number of octets metadata ::= attribute [ "(" 1#metadata-type ")" ] metadata-partial ::= "value<" number "." nz-number ">" metadata-type ::= "acl" / "attribute" / "myrights" / "size" / metadata-partial / "value" number ::= 1*DIGIT nz-number ::= DIGIT-NZ *DIGIT ordering ::= ("+" / "-") atom quota-root ::= dataset quoted ::= <"> *QUOTED-CHAR <"> Newman [Page 46]
Internet DRAFT ACAP March 21, 1997 response ::= *response-data response-done response-addto ::= "*" SPACE "ADDTO" SPACE context SPACE entry-name SPACE number SPACE #return-data response-bye ::= "*" SPACE "BYE" SPACE resp-body CRLF ;; Server will disconnect condition response-change ::= "*" SPACE "CHANGE" SPACE context SPACE entry-name SPACE number SPACE number SPACE #return-data response-data ::= response-change / response-deleted / response-entry / response-mtimei / response-mtimeu / response-myright / response-remove / response-stat / response-bye response-deleted ::= tag SPACE "DELETED" SPACE entry-name response-done ::= tag SPACE resp-cond-state CRLF response-entry ::= tag SPACE "ENTRY" SPACE entry SPACE #return-data response-extend ::= tag SPACE atom [SPACE 1#extension-data] response-mtimei ::= tag SPACE "MODTIME" SPACE time response-mtimeu ::= "*" SPACE "MODTIME" SPACE context SPACE time response-myright ::= tag SPACE "MYRIGHTS" SPACE acl-rights response-remove ::= "*" SPACE "REMOVEFROM" SPACE context SPACE entry-name SPACE number response-stat ::= "*" SPACE resp-cond-state CRLF resp-body ::= ["[" resp-code "]" SPACE] quoted resp-code ::= "ALERT" / "LOCKED" / "PERMISSION" / "QUOTA" / resp-code-refer / resp-code-many / "TRYFREECONTEXT" / resp-code-ext resp-code-ext ::= atom [SPACE 1#extension-data] ;; extension-data MUST NOT contain "]" resp-code-many ::= "TOOMANY" SPACE nz_number resp-code-refer ::= "REFER" SPACE 1#(<"> url-relative <">) Newman [Page 47]
Internet DRAFT ACAP March 21, 1997 resp-cond-state ::= ("OK" / "NO" / "BAD") SPACE resp-body ;; Status condition return-data ::= string / number searchkey-equal ::= "EQUAL" SPACE attribute SPACE ordering SPACE value searchkey-comp ::= "COMPARE" SPACE attribute SPACE ordering SPACE value searchkey-strict ::= "COMPARESTRICT" SPACE attribute SPACE ordering SPACE value searchkey-range ::= "RANGE" SPACE nz-number SPACE nz-number searchmod-depth ::= "DEPTH" SPACE number searchmod-limit ::= "LIMIT" SPACE number SPACE number searchmod-make ::= "MAKECONTEXT" SPACE context searchmod-notify ::= "NOTIFYCONTEXT" searchmod-return ::= "RETURN" SPACE "(" #metadata ")" searchmod-sort ::= "SORT" SPACE "(" 1#(attribute SPACE ordering) ")" search-criteria ::= searchkey-equal / searchkey-comp / searchkey-strict / searchkey-range / "NOT" SPACE search-criteria / "OR" SPACE search-criteria SPACE search-criteria / "AND" SPACE search-criteria SPACE search-criteria search-modifier ::= searchmod-depth / searchmod-limit / searchmod-make / searchmod-notify / searchmod-return / searchmod-sort string ::= quoted / literal tag ::= 1*<any ATOM-CHAR except "+" or "*"> time ::= <"> time-year time-month time-day time-hour time-minute time-second time-subsecond <"> time-day ::= 2DIGIT ;; 00-31 time-hour ::= 2DIGIT ;; 00-23 time-minute ::= 2DIGIT ;; 00-59 Newman [Page 48]
Internet DRAFT ACAP March 21, 1997 time-month ::= 2DIGIT ;; 01-12 time-second ::= 2DIGIT ;; 00-60 time-subsecond ::= *DIGIT time-year ::= 4DIGIT value ::= string url-acap ::= "acap://" url-server "/" url-enc-entry [url-filter] ;; url-enc-entry interpreted relative to "/" url-attr-list ::= url-enc-attr *("&" url-enc-attr) url-auth ::= ";AUTH=" ("*" / auth-type) url-achar ::= uchar / "&" / "=" / "~" ;; See RFC 1738 for definition of "uchar" url-char ::= uchar / "=" / "~" / ":" / "@" / "/" ;; See RFC 1738 for definition of "uchar" url-depth ::= "DEPTH=" number url-enc-attr ::= 1*url-char ;; encoded version of attribute name url-enc-auth ::= 1*url-achar ;; encoded version of auth-type above url-enc-entry ::= 1*url-char ;; encoded version of entry-relative above url-enc-search ::= 1*url-char ;; encoded version of search-criteria above url-enc-user ::= *url-achar ;; encoded version of login userid url-filter ::= "?" url-attr-list ["?" url-depth ["?" url-enc-search]] url-relative ::= url-acap / [url-enc-entry] [url-filter] ;; url-enc-entry is relative to base URL url-server ::= [url-user [url-auth] "@"] hostport ;; See RFC 1738 for definition of "hostport" Newman [Page 49]
Internet DRAFT ACAP March 21, 1997 9. Security Considerations ACAP protocol transactions, including address book and option data, are sent in the clear over the network unless the optional privacy protection is negotiated in the AUTHENTICATE command. Use of the LOGIN command sends passwords in the clear. This can be avoided by using the AUTHENTICATE command instead. Additional security considerations are discussed in the section discussing the AUTHENTICATE and LOGIN commands. 10. Authors' Addresses Chris Newman Innosoft International, Inc. 1050 East Garvey Ave. South West Covina, CA 91790 USA Email: chris.newman@innosoft.com John G. Myers Email: jgm+@cmu.edu Newman [Page 50]
Internet DRAFT ACAP March 21, 1997 Appendices A. References [IMAP4] Crispin, M., "Internet Message Access Protocol - Version 4rev1", RFC 2060, University of Washington, December 1996. <ftp://ds.internic.net/rfc/rfc2060.txt> [IMAP-ACL] Myers, J., "IMAP4 ACL extension", RFC 2086, Carnegie Mellon, January 1997. <ftp://ds.internic.net/rfc/rfc2086.txt> [SASL] Myers, J., "Simple Authentication and Security Layer (SASL)", draft-myers-auth-sasl-xx.txt [IMAIL] Crocker, D., "Standard for the Format of ARPA Internet Text Messages", STD 11, RFC 822, University of Delaware, August 1982. <ftp://ds.internic.net/rfc/rfc822.txt> [UTF8] Yergeau, F. "UTF-8, a transformation format of Unicode and ISO 10646", RFC 2044, Alis Technologies, October 1996. <ftp://ds.internic.net/rfc/rfc2044.txt> [BASIC-URL] Berners-Lee, Masinter, McCahill, "Uniform Resource Locators (URL)", RFC 1738, CERN, Xerox Coproration, University of Minnesota, December 1994. <ftp://ds.internic.net/rfc/rfc1738.txt> [REL-URL] Fielding, "Relative Uniform Resource Locators", RFC 1808, UC Irvine, June 1995. <ftp://ds.internic.net/rfc/rfc1808.txt> Newman [Page 51]
Internet DRAFT ACAP March 21, 1997 B. ACAP Keyword Index ACAP (untagged response) ................................... 16 ADDTO (untagged response) .................................. 28 ALERT (response code) ...................................... 14 AND (search keyword) ....................................... 25 AUTHENTICATE (command) ..................................... 20 BAD (response) ............................................. 19 BYE (untagged response) .................................... 19 CHANGE (untagged response) ................................. 28 COMPARE (search keyword) ................................... 25 COMPARESTRICT (search keyword) ............................. 26 CONTEXTLIMIT (ACAP capability) ............................. 17 DELETE (command) ........................................... 30 DELETEACL (command) ........................................ 33 DELETED (intermediate response) ............................ 31 DELETEDSINCE (command) ..................................... 30 DEPTH (search modifier) .................................... 23 ENTRY (intermediate response) .............................. 26 EQUAL (search keyword) ..................................... 26 FREECONTEXT (command) ...................................... 27 GETQUOTA (command) ......................................... 35 IMPLEMENTATION (ACAP capability) ........................... 17 LIMIT (search modifier) .................................... 23 LOCK (command) ............................................. 36 LOCKED (response code) ..................................... 14 LOGIN (command) ............................................ 22 LOGOUT (command) ........................................... 18 MAKECONTEXT (search modifier) .............................. 23 MODTIME (intermediate response) ............................ 26 MODTIME (untagged response) ................................ 29 MYRIGHTS (command) ......................................... 34 MYRIGHTS (intermediate response) ........................... 34 NO (response) .............................................. 18 NOOP (command) ............................................. 17 NOT (search keyword) ....................................... 26 NOTIFYCONTEXT (search modifier) ............................ 24 OK (response) .............................................. 18 OR (search keyword) ........................................ 26 ORDERINGS (ACAP capability) ................................ 17 PERMISSION (response code) ................................. 14 QUOTA (intermediate response) .............................. 36 QUOTA (response code) ...................................... 14 RANGE (search keyword) ..................................... 26 REFER (response code) ...................................... 14 REMOVEFROM (untagged response) ............................. 28 RETURN (search modifier) ................................... 24 SASL (ACAP capability) ..................................... 17 Newman [Page 52]
Internet DRAFT ACAP March 21, 1997 SEARCH (command) ........................................... 22 SETACL (command) ........................................... 33 SETQUOTA (command) ......................................... 35 SORT (search keyword) ...................................... 25 STORE (command) ............................................ 29 TOOMANY (response code) .................................... 14 TRYFREECONTEXT (response code) ............................. 15 UNLOCK (command) ........................................... 37 UPDATECONTEXT (command) .................................... 27 acl (attribute metadata) ................................... 9 anyone (ACL identifier) .................................... 31 attribute (attribute metadata) ............................. 9 createtime (predefined attribute) .......................... 8 dataset.acl (dataset attribute) ............................ 39 dataset.acl.<attribute> (dataset attribute) ................ 39 dataset.inherit (dataset attribute) ........................ 39 dataset.sort-hint.<attribute> (dataset attribute) .......... 40 en-nocase (ordering function) .............................. 13 entry (predefined attribute) ............................... 8 modtime (predefined attribute) ............................. 8 myrights (attribute metadata) .............................. 9 numeric (ordering function) ................................ 14 octet (ordering function) .................................. 13 size (attribute metadata) .................................. 9 subdataset (predefined attribute) .......................... 8 value (attribute metadata) ................................. 9 value<ORIGIN.SIZE> (attribute metadata) .................... 9 Newman [Page 53]
