1 APPLICATION LAYER PROTOCOL FOR THE CITADEL SYSTEM
2 (c) 1995-2005 by Art Cancro et. al. All Rights Reserved
8 This is an attempt to document the application layer protocol used by the
9 Citadel system, beginning with version 4.00, which is the first version
10 to implement a client/server paradigm. It is intended as a resource for
11 programmers who intend to develop their own Citadel clients, but it may have
15 IMPORTANT NOTE TO DEVELOPERS!
16 -----------------------------
18 Anyone who wants to add commands or other functionality to this protocol,
19 *please* get in touch so that these efforts can be coordinated. New
20 commands added by other developers can be added to this document, so we
21 don't end up with new server commands from multiple developers which have
22 the same name but perform different functions. If you don't coordinate new
23 developments ahead of time, please at least send in an e-mail documenting
24 what you did, so that your new commands can be added to this document.
26 The coordinator of the Citadel project is Art Cancro
27 <ajc@uncensored.citadel.org>.
30 CONNECTING TO A SERVER
31 ----------------------
33 The protocols used below the application layer are beyond the scope of this
34 document, but we will briefly cover the methodology employed by Citadel.
36 Citadel offers its client protocol using TCP/IP. It does so via a
37 multithreaded server listening on a TCP port. Local connections may also
38 be made using the same protocol using Unix domain sockets.
40 The port number officially assigned to Citadel by the IANA is 504/tcp. Since
41 our application layer assumes a clean, reliable, sequenced connection, the use
42 of UDP would render the server unstable and unusable, so we stick with TCP.
48 The native character set for the Citadel system is UTF-8. Unless otherwise
49 specified, all data elements are expected to be in the UTF-8 character set.
50 Specifically, all non-MIME messages should be assumed to be in UTF-8. MIME
51 messages may be in whatever character set is specified by the MIME header, of
52 course; however, some clients (such as WebCit) will automatically convert
53 messages from other character sets before displaying them.
56 GENERAL INFORMATION ABOUT THE SERVER
57 ------------------------------------
59 The server is connection-oriented and stateful: each client requires its own
60 connection to a server process, and when a command is sent, the client must
61 read the response, and then transfer data or change modes if necessary.
63 The application layer is very much like other Internet protocols such as SMTP
64 or NNTP. A client program sends one-line commands to the server, and the
65 server responds with a three-digit numeric result code followed by a message
66 describing what happened. This cycle continues until the end of the
69 Unlike protocols such as FTP, all data transfers occur in-band. This means
70 that the same connection that is used for exchange of client/server
71 messages, will also be used to transfer data back and forth. (FTP opens a
72 separate connection for data transfers.) This keeps protocol administration
73 straightforward, as it can traverse firewalls without any special protocol
74 support on the firewall except for opening the port number.
80 The server will respond to all commands with a 3-digit result code, which
81 will be the first three characters on the line. The rest of the line may
82 contain a human-readable string explaining what happened. (Some client
83 software will display some of these strings to the user.)
85 The first digit is the most important. The following codes are defined for
86 this position: ERROR, OK, MORE_DATA, LISTING_FOLLOWS, and SEND_LISTING.
88 The second and third digits may provide a reason as to why a command
89 succeeded or failed. See ipcdef.h for the available codes.
91 ERROR means the command did not complete.
92 OK means the command executed successfully.
93 MORE_DATA means the command executed partially. Usually this means that
94 another command needs to be executed to complete the operation. For example,
95 sending the USER command to log in a user usually results in a MORE_DATA
96 result code, because the client needs to execute a PASS command to send the
97 password and complete the login.
98 LISTING_FOLLOWS means that after the server response, the server will
99 output a listing of some sort. The client *must* read the listing, whether
100 it wants to or not. The end of the listing is signified by the string
101 "000" on a line by itself.
102 SEND_LISTING is the opposite of LISTING_FOLLOWS. It means that the client
103 should begin sending a listing of some sort. The client *must* send something,
104 even if it is an empty listing. Again, the listing ends with "000" on a line
106 BINARY_FOLLOWS and SEND_BINARY mean that the client must immediately send
107 or receive a block of binary data. The first parameter will always be the
109 ASYNC_MESSAGE_FOLLOWS means that an asynchronous, or unsolicited, message
110 follows. The next line will be one of the above codes, and if a data transfer
111 is involved it must be handled immediately. Note that the client will not
112 receive this type of response unless it indicates to the server that it is
113 capable of handling them; see the writeup of the ASYN command later in this
119 Zero or more parameters may be passed to a command. When more than one
120 parameter is passed to a command, they should be separated by the "|"
123 In this example, we're using the "SETU" command and passing three
124 parameters: 80, 24, and 260.
126 When the server spits out data that has parameters, if more than one
127 parameter is returned, they will be separated by the "|" symbol like
130 In this example, we just executed the "GETU" command, and it returned us
131 an OK result code (the '2' in the 200) and three parameters: 80, 24, and
138 This is a listing of all the commands that a Citadel server can execute.
143 This command does nothing. It takes no arguments and always returns
144 OK. It is intended primarily for testing and development, but it might also
145 be used as a "keep alive" command to prevent the server from timing out, if
146 it's running over a transport that needs this type of thing.
149 ECHO (ECHO something)
151 This command also does nothing. It simply returns OK followed by whatever
157 Terminate the server connection. This command takes no arguments. It
158 returns OK and closes the connection immediately.
163 Log out the user without closing the server connection. It always returns
164 OK even if no user is logged in.
167 USER (send USER name)
169 The first step in logging in a user. This command takes one argument: the
170 name of the user to be logged in. If the user exists, a MORE_DATA return
171 code will be sent, which means the client should execute PASS as the next
172 command. If the user does not exist, ERROR + NO_SUCH_USER is returned.
177 The second step in logging in a user. This command takes one argument: the
178 password for the user we are attempting to log in. If the password doesn't
179 match the correct password for the user we specified for the USER command,
180 ERROR + PASSWORD_REQUIRED is returned. If a USER command has not been
181 executed yet, ERROR + USERNAME_REQUIRED is returned. If a user is already
182 logged in, ERROR + ALREADY_LOGGED_IN is returned. If the password is
183 correct, OK is returned and the user is now logged in... and most of the
184 other server commands can now be executed. Along with OK, the following
185 parameters are returned:
187 0 - The user's name (in case the client wants the right upper/lower casing)
188 1 - The user's current access level
191 4 - Various flags (see citadel.h)
193 6 - Time of last call (UNIX timestamp)
196 NEWU (create NEW User account)
198 This command creates a new user account AND LOGS IT IN. The argument to
199 this command will be the name of the account. No case conversion is done
200 on the name. Note that the new account is installed with a default
201 configuration, and no password, so the client should immediately prompt the
202 user for a password and install it with the SETP command as soon as this
203 command completes. This command returns OK if the account was created and
204 logged in, ERROR + ALREADY_EXISTS if another user already exists with this
205 name, ERROR + NOT_HERE if self-service account creation is disabled,
206 ERROR + MAX_SESSIONS_EXCEEDED if too many users are logged in, ERROR +
207 USERNAME_REQUIRED if a username was not provided, or ERROR + ILELGAL_VALUE
208 if the username provided is invalid. If OK, it will also return the same
209 parameters that PASS returns.
211 Please note that the NEWU command should only be used for self-service
212 user account creation. For administratively creating user accounts, please
213 use the CREU command.
216 SETP (SET new Password)
218 This command sets a new password for the currently logged in user. The
219 argument to this command will be the new password. The command always
220 returns OK, unless the client is not logged in, in which case it will return
221 ERROR + NOT_LOGGED_IN, or if the user is an auto-login user, in which case
222 it will return ERROR + NOT_HERE.
225 CREU (CREate new User account)
227 This command creates a new user account AND DOES NOT LOG IT IN. The first
228 argument to this command will be the name of the account. No case conversion
229 is done on the name. Note that the new account is installed with a default
230 configuration, and no password. The second argument is optional, and will be
231 an initial password for the user. This command returns OK if the account was
232 created, ERROR + HIGHER_ACCESS_REQUIRED if the user is not an Aide, ERROR +
233 USERNAME_REQUIRED if no username was specified, or ERROR + ALREADY_EXISTS if
234 another user already exists with this name.
236 Please note that CREU is intended to be used for activities in which a
237 system administrator is creating user accounts. For self-service user
238 account creation, use the NEWU command.
241 LKRN (List Known Rooms with New messages)
243 List known rooms with new messages. If the client is not logged in, ERROR +
244 NOT_LOGGED_IN is returned. Otherwise, LISTING_FOLLOWS is returned, followed
245 by the room listing. Each line in the listing contains the full name of a
246 room, followed by the '|' symbol, and then a number that may contain the
249 #define QR_PERMANENT 1 /* Room does not purge */
250 #define QR_PRIVATE 4 /* Set for any type of private room */
251 #define QR_PASSWORDED 8 /* Set if there's a password too */
252 #define QR_GUESSNAME 16 /* Set if it's a guessname room */
253 #define QR_DIRECTORY 32 /* Directory room */
254 #define QR_UPLOAD 64 /* Allowed to upload */
255 #define QR_DOWNLOAD 128 /* Allowed to download */
256 #define QR_VISDIR 256 /* Visible directory */
257 #define QR_ANONONLY 512 /* Anonymous-Only room */
258 #define QR_ANON2 1024 /* Anonymous-Option room */
259 #define QR_NETWORK 2048 /* Shared network room */
260 #define QR_PREFONLY 4096 /* Preferred status needed to enter */
261 #define QR_READONLY 8192 /* Aide status required to post */
263 Then it returns another '|' symbol, followed by a second set of bits comprised
266 #define QR2_SYSTEM 1 /* System room; hide by default */
267 #define QR2_SELFLIST 2 /* Self-service mailing list mgmt */
269 Other bits may be defined in the future. The listing terminates, as with
270 all listings, with "000" on a line by itself.
272 Starting with version 4.01 and above, floors are supported. The first
273 argument to LKRN should be the number of the floor to list rooms from. Only
274 rooms from this floor will be listed. If no arguments are passed to LKRN, or
275 if the floor number requested is (-1), rooms on all floors will be listed.
277 The third field displayed on each line is the number of the floor the room
278 is on. The LFLR command should be used to associate floor numbers with
281 The fourth field displayed on each line is a "room listing order." Unless
282 there is a compelling reason not to, clients should sort any received room
283 listings by this value.
285 The fifth field is a special bit bucket containing fields which pertain to
286 room access controls:
288 #define UA_KNOWN 2 /* Known room */
289 #define UA_GOTOALLOWED 4 /* Access will be granted to this room
290 * if the user calls it up by name */
291 #define UA_HASNEWMSGS 8 /* Unread messages exist in room */
292 #define UA_ZAPPED 16 /* Zapped from known rooms list */
294 The sixth field is the user's current view for the room. (See VIEW command)
297 LKRO (List Known Rooms with Old [no new] messages)
299 This follows the same usage and format as LKRN.
302 LZRM (List Zapped RooMs)
304 This follows the same usage and format as LKRN and LKRO.
307 LKRA (List All Known Rooms)
309 Same format. Lists all known rooms, with or without new messages.
312 LRMS (List all accessible RooMS)
314 Again, same format. This command lists all accessible rooms, known and
315 forgotten, with and without new messages. It does not, however, list
316 inaccessible private rooms.
319 LPRM (List all Public RooMs)
321 Again, same format. This command lists all public rooms, and nothing else.
322 Unlike the other list rooms commands, this one can be executed without logging
326 GETU (GET User configuration)
328 This command retrieves the screen dimensions and user options for the
329 currently logged in account. ERROR + NOT_LOGGED_IN will be returned if no
330 user is logged in, of course. Otherwise, OK will be returned, followed by
331 four parameters. The first parameter is the user's screen width, the second
332 parameter is the user's screen height, and the third parameter is a bag of
333 bits with the following meanings:
335 #define US_LASTOLD 16 /* Print last old message with new */
336 #define US_EXPERT 32 /* Experienced user */
337 #define US_UNLISTED 64 /* Unlisted userlog entry */
338 #define US_NOPROMPT 128 /* Don't prompt after each message */
339 #define US_DISAPPEAR 512 /* Use "disappearing msg prompts" */
340 #define US_PAGINATOR 2048 /* Pause after each screen of text */
342 There are other bits, too, but they can't be changed by the user (see below).
345 SETU (SET User configuration)
347 This command does the opposite of SETU: it takes the screen dimensions and
348 user options (which were probably obtained with a GETU command, and perhaps
349 modified by the user) and writes them to the user account. This command
350 should be passed three parameters: the screen width, the screen height, and
351 the option bits (see above). It returns ERROR + NOT_LOGGED_IN if no user is
352 logged in, and ERROR + ILLEGAL_VALUE if the parameters are incorrect.
354 Note that there exist bits here which are not listed in this document. Some
355 are flags that can only be set by Aides or the system administrator. SETU
356 will ignore attempts to toggle these bits. There also may be more user
357 settable bits added at a later date. To maintain later downward compatibility,
358 the following procedure is suggested:
360 1. Execute GETU to read the current flags
361 2. Toggle the bits that we know we can toggle
362 3. Execute SETU to write the flags
364 If we are passed a bit whose meaning we don't know, it's best to leave it
365 alone, and pass it right back to the server. That way we can use an old
366 client on a server that uses an unknown bit without accidentally clearing
367 it every time we set the user's configuration.
372 This command is used to goto a new room. When the user first logs in (login
373 is completed after execution of the PASS command) this command is
374 automatically and silently executed to take the user to the first room in the
375 system (usually called the Lobby).
377 This command can be passed one or two parameters. The first parameter is,
378 of course, the name of the room. Although it is not case sensitive, the
379 full name of the room must be used. Wildcard matching or unique string
380 matching of room names should be the responsibility of the client.
382 Note that the reserved room name "_BASEROOM_" can be passed to the server
383 to cause the goto command to take the user to the first room in the system,
384 traditionally known as the Lobby>. As long as a user is logged in, a
385 GOTO command to _BASEROOM_ is guaranteed to succeed. This is useful to
386 allow client software to return to the base room when it doesn't know
389 There are also several additional reserved room names:
390 "_MAIL_" goes to the user's inbox (i.e. the Mail> room).
391 "_BITBUCKET_" goes to a room that has been chosen for messages without a home.
392 "_CALENDAR_" goes to the user's primary personal calendar.
393 "_CONTACTS_" goes to the user's primary personal address book.
394 "_NOTES_" goes to the user's primary personal notes room.
395 "_TASKS_" goes to the user's primary personal task list.
398 The second (and optional) parameter is a password, if one is required for
399 access to the room. This allows for all types of rooms to be accessed via
400 this command: for public rooms, invitation-only rooms to which the user
401 has access, and preferred users only rooms to which the user has access, the
402 room will appear in a room listing. For guess-name rooms, this command
403 will work transparently, adding the room to the user's known room list when
404 it completes. For passworded rooms, access will be denied if the password
405 is not supplied or is incorrect, or the command will complete successfully
406 if the password is correct.
408 The third (and also) optional parameter is a "transient" flag. Normally,
409 when a user enters a private and/or zapped room, the room is added to the
410 user's known rooms list. If the transient flag is set to non-zero, this is
411 called a "transient goto" which causes the user to enter the room without
412 adding the room to the known rooms list.
414 The possible result codes are:
416 OK - The command completed successfully. User is now in the room.
417 (See the list of returned parameters below)
419 ERROR - The command did not complete successfully. Check the second and
420 third positions of the result code to find out what happened:
422 NOT_LOGGED_IN - Of course you can't go there. You didn't log in.
423 PASSWORD_REQUIRED - Either a password was not supplied, or the supplied
424 password was incorrect.
425 ROOM_NOT_FOUND - The requested room does not exist.
427 The typical procedure for entering a passworded room would be:
429 1. Execute a GOTO command without supplying any password.
430 2. ERROR + PASSWORD_REQUIRED will be returned. The client now knows that
431 the room is passworded, and prompts the user for a password.
432 3. Execute a GOTO command, supplying both the room name and the password.
433 4. If OK is returned, the command is complete. If, however,
434 ERROR + PASSWORD_REQUIRED is still returned, tell the user that the supplied
435 password was incorrect. The user remains in the room he/she was previously
438 When the command succeeds, these parameters are returned:
439 0. The name of the room
440 1. Number of unread messages in this room
441 2. Total number of messages in this room
442 3. Info flag: set to nonzero if the user needs to read this room's info
443 file (see RINF command below)
444 4. Various flags associated with this room. (See LKRN cmd above)
445 5. The highest message number present in this room
446 6. The highest message number the user has read in this room
447 7. Boolean flag: 1 if this is a Mail> room, 0 otherwise.
448 8. Aide flag: 1 if the user is either the Room Aide for this room, *or* is
449 a regular Aide (this makes access checks easy).
450 9. The number of new Mail messages the user has (useful for alerting the
451 user to the arrival of new mail during a session)
452 10. The floor number this room resides on
453 11. The *current* "view" for this room (see views.txt for more info)
454 12. The *default* "view" for this room
456 The default view gives the client a hint as to what views the user should
457 be allowed to select. For example, it would be confusing to allow messages
458 in a room intended for calendar items. The server does not enforce these
459 restrictions, though.
462 MSGS (get pointers to MeSsaGeS in this room)
464 This command obtains a listing of all the messages in the current room
465 which the client may request. This command may be passed a single parameter:
466 either "all", "old", or "new" to request all messages, only old messages, or
467 new messages. Or it may be passed two parameters: "last" plus a number, in
468 which case that many message pointers will be returned; "first" plus a
469 number, for the corresponding effect; or "gt" plus a number, to list all
470 messages in the current room with a message number greater than the one
471 specified. If no parameters are specified, "all" is assumed.
473 The third argument, may be either 0 or 1. If it is 1, this command behaves
474 differently: before a listing is returned, the client must transmit a list
475 of fields to search for. The field headers are listed below in the writeup
476 for the "MSG0" command.
478 The optional fourth argument may also be either 0 or 1. If it is 1, the
479 output of this command will include not only a list of message numbers, but
480 a simple header summary of each message as well. This is somewhat resource
481 intensive so you shouldn't do this unless you absolutely need all the headers
482 immediately. The fields which are output (in the usual delimited fashion, of
483 course) are: message number, timestamp, display name, node name, Internet
484 email address (if present), subject (if present).
486 This command can return three possible results. ERROR + NOT_LOGGED_IN will
487 be returned if no user is currently logged in. Otherwise, LISTING_FOLLOWS
488 will be returned, and the listing will consist of zero or more message
489 numbers, one per line. The listing ends, as always, with the string "000"
490 alone on a line by itself. The listed message numbers can be used to request
491 messages from the system. If "search mode" is being used, the server will
492 return START_CHAT_MODE, and the client is expected to transmit the search
493 criteria, and then read the message list.
495 Since this is somewhat complex, here are some examples:
497 Example 1: Read all new messages
500 Server: 100 Message list...
506 Example 2: Read the last five messages
509 Server: 100 Message list...
517 Example 3: Read all messages written by "IGnatius T Foobar"
520 Server: 800 Send template then receive message list
521 Client: from|IGnatius T Foobar
535 Note that in "search mode" the client may specify any number of search
536 criteria. These criteria are applied with an AND logic.
539 MSG0 (read MeSsaGe, mode 0)
541 This is a command used to read the text of a message. "Mode 0" implies that
542 other MSG commands (MSG1, MSG2, etc.) will probably be added later on to read
543 messages in more robust formats. This command should be passed two arguments.
544 The first is the message number of the message being requested. The second
545 argument specifies whether the client wants headers and/or message body:
549 3 = Headers only, with MIME information suppressed (this runs faster)
551 If the request is denied, ERROR + NOT_LOGGED_IN or ERROR + MESSAGE_NOT_FOUND
552 will be returned. Otherwise, LISTING_FOLLOWS will be returned, followed by
553 the contents of the message. The following fields may be sent:
555 type= Formatting type. The currently defined types are:
556 0 = "traditional" Citadel formatting. This means that newlines should be
557 treated as spaces UNLESS the first character on the next line is a space. In
558 other words, only indented lines should generate a newline on the user's screen
559 when the message is being displayed. This allows a message to be formatted to
560 the reader's screen width. It also allows the use of proportional fonts.
561 1 = a simple fixed-format message. The message should be displayed to
562 the user's screen as is, preferably in a fixed-width font that will fit 80
564 4 = MIME format message. The message text is expected to contain a header
565 with the "Content-type:" directive (and possibly others).
567 msgn= The message ID of this message on the system it originated on.
568 path= An e-mailable path back to the user who wrote the message.
570 time= The date and time of the message, in Unix format (the number of
571 seconds since midnight on January 1, 1970, GMT).
573 from= The name of the author of the message.
574 rcpt= If the message is a private e-mail, this is the recipient.
575 room= The name of the room the message originated in.
576 node= The short node name of the system this message originated on.
577 hnod= The long node name of the system this message originated on.
578 zaps= The id/node of a message which this one zaps (supersedes).
580 part= Information about a MIME part embedded in this message.
581 pref= Information about a multipart MIME prefix such as "multipart/mixed"
582 or "multipart/alternative". This will be output immediately prior
583 to the various "part=" lines which make up the multipart section.
584 suff= Information about a multipart MIME suffix. This will be output
585 immediately following the various "part=" lines which make up the
588 text Note that there is no "=" after the word "text". This string
589 signifies that the message text begins on the next line.
592 WHOK (WHO Knows room)
594 This command is available only to Aides. ERROR + HIGHER_ACCESS_REQUIRED
595 will be returned if the user is not an Aide. Otherwise, it returns
596 LISTING_FOLLOWS and then lists, one user per line, every user who has
597 access to the current room.
600 INFO (get server INFO)
602 This command will *always* return LISTING_FOLLOWS and then print out a
603 listing of zero or more strings. Client software should be written to expect
604 anywhere from a null listing to an infinite number of lines, to allow later
605 backward compatibility. The current implementation defines the following
606 parts of the listing:
608 Line 1 - Your unique session ID on the server
609 Line 2 - The node name of the Citadel server
610 Line 3 - Human-readable node name of the Citadel server
611 Line 4 - The fully-qualified domain name (FQDN) of the server
612 Line 5 - The name of the server software, i.e. "Citadel 4.00"
613 Line 6 - (The revision level of the server code) * 100
614 Line 7 - The geographical location of the site (city and state if in the US)
615 Line 8 - The name of the system administrator
616 Line 9 - A number identifying the server type (see below)
617 Line 10 - The text of the system's paginator prompt
618 Line 11 - Floor Flag. 1 if the system supports floors, 0 otherwise.
619 Line 12 - Paging level. 0 if the system only supports inline paging,
620 1 if the system supports "extended" paging (check-only and
621 multiline modes). See the SEXP command for further information.
622 Line 13 - The "nonce" for this session, for support of APOP-style
623 authentication. If this field is present, clients may authenticate
625 Line 14 - Set to nonzero if this server supports the QNOP command.
626 Line 15 - Set to nonzero if this server is capable of connecting to a
627 directory service using LDAP.
629 *** NOTE! *** The "server type" code is intended to promote global
630 compatibility in a scenario in which developers have added proprietary
631 features to their servers or clients. We are attempting to avoid a future
632 situation in which users need to keep different client software around for
633 each Citadel they use. *Please*, if you are a developer and plan to add
634 proprietary features:
636 -> Your client programs should still be able to utilize servers other than
638 -> Clients other than your own should still be able to utilize your server,
639 even if your proprietary extensions aren't supported.
640 -> Please contact Art Cancro <ajc@uncensored.citadel.org> and obtain a unique
641 server type code, which can be assigned to your server program.
642 -> If you document what you did in detail, perhaps it can be added to a
643 future release of the Citadel program, so everyone can enjoy it. Better
644 yet, just work with the Citadel development team on the main source tree.
646 If everyone follows this scheme, we can avoid a chaotic situation with lots
647 of confusion about which client program works with which server, etc. Client
648 software can simply check the server type (and perhaps the revision level)
649 to determine ahead of time what commands may be utilized.
651 Please refer to "developers.txt" for information on what codes belong to whom.
655 RDIR (Read room DIRectory)
657 Use this command to read the directory of a directory room. ERROR + NOT_HERE
658 will be returned if the room has no directory, ERROR + HIGHER_ACCESS_REQUIRED
659 will be returned if the room's directory is not visible and the user does not
660 have Aide or Room Aide privileges, ERROR + NOT_LOGGED_IN will be returned if
661 the user is not logged in; otherwise LISTING_FOLLOWS will be returned,
662 followed by the room's directory. Each line of the directory listing will
663 contain three fields: a filename, the length of the file, and a description.
665 The server message contained on the same line with LISTING_FOLLOWS will
666 contain the name of the system and the name of the directory, such as:
668 uncensored.citadel.org|/usr/local/citadel/files/my_room_directory
671 SLRP (Set Last-message-Read Pointer)
673 This command marks all messages in the current room as read (seen) up to and
674 including the specified number. Its sole parameter is the number of the last
675 message that has been read. This allows the pointer to be set at any
676 arbitrary point in the room. Optionally, the parameter "highest" may be used
677 instead of a message number, to set the pointer to the number of the highest
678 message in the room, effectively marking all messages in the room as having
679 been read (ala the Citadel <G>oto command).
681 The command will return OK if the pointer was set, or ERROR + NOT_LOGGED_IN
682 if the user is not logged in. If OK is returned, it will be followed by a
683 single argument containing the message number the last-read-pointer was set to.
686 INVT (INViTe a user to a room)
688 This command may only be executed by Aides, or by the room aide for the
689 current room. It is used primarily to add users to invitation-only rooms,
690 but it may also be used in other types of private rooms as well. Its sole
691 parameter is the name of the user to invite.
693 The command will return OK if the operation succeeded. ERROR + NO_SUCH_USER
694 will be returned if the user does not exist, ERROR + HIGHER_ACCESS_REQUIRED
695 will be returned if the operation would have been possible if the user had
696 higher access, and ERROR + NOT_HERE may be returned if the room is not a
700 KICK (KICK a user out of a room)
702 This is the opposite of INVT: it is used to kick a user out of a private
703 room. It can also be used to kick a user out of a public room, but the
704 effect will only be the same as if the user <Z>apped the room - a non-stupid
705 user can simply un-zap the room to get back in.
708 GETR (GET Room attributes)
710 This command is used for editing the various attributes associated with a
711 room. A typical "edit room" command would work like this:
712 1. Use the GETR command to get the current attributes
713 2. Change some of them around
714 3. Use SETR (see below) to save the changes
715 4. Possibly also change the room aide using the GETA and SETA commands
717 GETR takes no arguments. It will only return OK if the SETR command will
718 also return OK. This allows client software to tell the user that he/she
719 can't edit the room *before* going through the trouble of actually doing the
720 editing. Possible return codes are:
722 ERROR+NOT_LOGGED_IN - No user is logged in.
723 ERROR+HIGHER_ACCESS_REQUIRED - Not enough access. Typically, only aides
724 and the room aide associated with the current room, can access this command.
725 OK - Command succeeded. Parameters are returned.
727 If OK is returned, the following parameters will be returned as well:
729 0. The name of the room
730 1. The room's password (if it's a passworded room)
731 2. The name of the room's directory (if it's a directory room)
732 3. Various flags (bits) associated with the room (see LKRN cmd above)
733 4. The floor number on which the room resides
734 5. The room listing order
735 6. The default view for the room (see views.txt)
736 7. A second set of flags (bits) associated with the room
739 SETR (SET Room attributes)
741 This command sets various attributes associated with the current room. It
742 should be passed the following arguments:
744 0. The name of the room
745 1. The room's password (if it's a passworded room)
746 2. The name of the room's directory (if it's a directory room)
747 3. Various flags (bits) associated with the room (see LKRN cmd above)
748 4. "Bump" flag (see below)
749 5. The floor number on which the room should reside
750 6. The room listing order
751 7. The default view for the room (see views.txt)
752 8. A second set of flags (bits) associated with the room
754 *Important: You should always use GETR to retrieve the current attributes of
755 the room, then change what you want to change, and then use SETR to write it
756 all back. This is particularly important with respect to the flags: if a
757 particular bit is set, and you don't know what it means, LEAVE IT ALONE and
758 only toggle the bits you want to toggle. This will allow for upward
761 The _BASEROOM_, user's Mail> and Aide> rooms can only be partially edited.
762 Any changes which cannot be made will be silently ignored.
764 If the room is a private room, you have the option of causing all users who
765 currently have access, to forget the room. If you want to do this, set the
766 "bump" flag to 1, otherwise set it to 0.
771 This command is used to get the name of the Room Aide for the current room.
772 It will return ERROR + NOT_LOGGED_IN if no user is logged in, or OK if the
773 command succeeded. Along with OK there will be returned one parameter: the
774 name of the Room Aide. A conforming server must guarantee that the user is
780 The opposite of GETA, used to set the Room Aide for the current room. One
781 parameter should be passed, which is the name of the user who is to be the
782 new Room Aide. Under Citadel, this command may only be executed by Aides
783 and by the *current* Room Aide for the room. Return codes possible are:
784 ERROR + NOT_LOGGED_IN (Not logged in.)
785 ERROR + HIGHER_ACCESS_REQUIRED (Higher access required.)
786 ERROR + NOT_HERE (Room cannot be edited.)
787 OK (Command succeeded.)
790 ENT0 (ENTer message, mode 0)
792 This command is used to enter messages into the system. It accepts four
795 0 - Post flag. This should be set to 1 to post a message. If it is
796 set to 0, the server only returns OK or ERROR (plus any flags describing
797 the error) without reading in a message. Client software should, in fact,
798 perform this operation at the beginning of an "enter message" command
799 *before* starting up its editor, so the user does not end up typing a message
800 in vain that will not be permitted to be saved. If it is set to 2, the
801 server will accept an "apparent" post name if the user is privileged enough.
802 This post name is arg 5.
803 1 - Recipient. This argument is utilized only for private mail messages.
804 It is ignored for public messages. It contains, of course, the name of the
805 recipient of the message.
806 2 - Anonymous flag. This argument is ignored unless the room allows
807 anonymous messages. In such rooms, this flag may be set to 1 to flag a
808 message as anonymous, otherwise 0 for a normal message.
809 3 - Format type. Any valid Citadel format type may be used (this will
810 typically be 0; see the MSG0 command above).
811 4 - Subject. If present, this argument will be used as the subject of
813 5 - Post name. When postflag is 2, this is the name you are posting as.
814 This is an Aide only command.
815 6 - Do Confirmation. NOTE: this changes the protocol semantics! When
816 you set this to nonzero, ENT0 will reply with a confirmation message after
817 you submit the message text. The reply code for the ENT0 command will be
818 START_CHAT_MODE instead of SEND_LISTING.
820 Possible result codes:
821 OK - The request is valid. (Client did not set the "post" flag, so the
822 server will not read in message text.) If the message is an e-mail with
823 a recipient, the text that follows the OK code will contain the exact name
824 to which mail is being sent. The client can display this to the user. The
825 implication here is that the name that the server returns will contain the
826 correct upper and lower case characters. In addition, if the recipient is
827 having his/her mail forwarded, the forwarding address will be returned.
828 SEND_LISTING - The request is valid. The client should now transmit
829 the text of the message (ending with a 000 on a line by itself, as usual).
830 START_CHAT_MODE - The request is valid. The client should now transmit
831 the text of the message, ending with a 000 on a line by itself. After
832 transmitting the 000 terminator, the client MUST read in the confirmation
833 from the server, which will also end with 000 on a line by itself. The format
834 of the confirmation appears below.
835 ERROR + NOT_LOGGED_IN - Not logged in.
836 ERROR + HIGHER_ACCESS_REQUIRED - Higher access is required. An
837 explanation follows, worded in a form that can be displayed to the user.
838 ERROR + NO_SUCH_USER - The specified recipient does not exist.
840 The format of the confirmation message, if requested, is as follows:
841 Line 1: The new message number on the server for the message. It will be
842 positive for a real message number, or negative to denote
843 that an error occurred. If an error occurred, the message was
845 Line 2: A human-readable confirmation or error message.
846 Line 3: The resulting Exclusive UID of the message, if present.
847 (More may be added to this in the future, so do not assume that there will
848 only be these lines output. Keep reading until 000 is received.)
851 RINF (read Room INFormation file)
853 Each room has associated with it a text file containing a description of
854 the room, perhaps containing its intended purpose or other important
855 information. The info file for the Lobby> (the system's base room) is
856 often used as a repository for system bulletins and the like.
858 This command, which accepts no arguments, is simply used to read the info
859 file for the current room. It will return LISTING_FOLLOWS followed by
860 the text of the message (always in format type 0) if the request can be
861 honored, or ERROR if no info file exists for the current room (which is
862 often the case). Other error description codes may accompany this result.
864 When should this command be used? This is, of course, up to the discretion
865 of client software authors, but in Citadel it is executed in two situations:
866 the first time the user ever enters a room; and whenever the contents of the
867 file change. The latter can be determined from the result of a GOTO command,
868 which will tell the client whether the file needs to be read (see GOTO above).
871 DELE (DELEte a message)
873 Delete a message from the current room. The one argument that should be
874 passed to this command is the message number of the message to be deleted.
875 The return value will be OK if the message was deleted, or an ERROR code.
876 If the delete is successful, the message's reference count is decremented, and
877 if the reference count reaches zero, the message is removed from the message
881 MOVE (MOVE or copy a message to a different room)
883 Move or copy a message to a different room. This command expects to be
884 passed three arguments:
885 0: the message number of the message to be moved or copied.
886 1: the name of the target room.
887 2: flag: 0 to move the message, 1 to copy it without deleting from the
890 This command never creates or deletes copies of a message; it merely moves
891 around links. When a message is moved, its reference count remains the same.
892 When a message is copied, its reference count is incremented.
895 KILL (KILL current room)
897 This command deletes the current room. It accepts a single argument, which
898 should be nonzero to actually delete the room, or zero to merely check
899 whether the room can be deleted.
901 Once the room is deleted, the current room is undefined. It is suggested
902 that client software immediately GOTO another room (usually _BASEROOM_)
903 after this command completes.
905 Possible return codes:
907 OK - room has been deleted (or, if checking only, request is valid).
908 ERROR+NOT_LOGGED_IN - no user is logged in.
909 ERROR+HIGHER_ACCESS_REQUIRED - not enough access to delete rooms.
910 ERROR+NOT_HERE - this room can not be deleted.
913 CRE8 (CRE[ate] a new room)
915 This command is used to create a new room. Like some of the other
916 commands, it provides a mechanism to first check to see if a room can be
917 created before actually executing the command. CRE8 accepts the following
920 0 - Create flag. Set this to 1 to actually create the room. If it is
921 set to 0, the server merely checks that there is a free slot in which to
922 create a new room, and that the user has enough access to create a room. It
923 returns OK if the client should go ahead and prompt the user for more info,
924 or ERROR or ERROR+HIGHER_ACCESS_REQUIRED if the command will not succeed.
925 1 - Name for new room.
926 2 - Access type for new room:
928 1 - Private; can be entered by guessing the room's name
929 2 - Private; can be entered by knowing the name *and* password
930 3 - Private; invitation only (sometimes called "exclusive")
931 4 - Personal (mailbox for this user only)
932 3 - Password for new room (if it is a type 2 room)
933 4 - Floor number on which the room should reside (optional)
934 5 - Set to 1 to avoid automatically gaining access to the created room.
935 6 - The default "view" for the room.
937 If the create flag is set to 1, the room is created (unless something
938 went wrong and an ERROR return is sent), and the server returns OK, but
939 the session is **not** automatically sent to that room. The client still
940 must perform a GOTO command to go to the new room.
943 FORG (FORGet the current room)
945 This command is used to forget (zap) the current room. For those not
946 familiar with Citadel, this terminology refers to removing the room from
947 a user's own known rooms list, *not* removing the room itself. After a
948 room is forgotten, it no longer shows up in the user's known room list,
949 but it will exist in the user's forgotten room list, and will return to the
950 known room list if the user goes to the room (in Citadel, this is
951 accomplished by explicitly typing the room's name in a <.G>oto command).
953 The command takes no arguments. If the command cannot execute for any
954 reason, ERROR will be returned. ERROR+NOT_LOGGED_IN or ERROR+NOT_HERE may
955 be returned as they apply.
957 If the command succeeds, OK will be returned. At this point, the current
958 room is **undefined**, and the client software is responsible for taking
959 the user to another room before executing any other room commands (usually
960 this will be _BASEROOM_ since it is always there).
963 MESG (read system MESsaGe)
965 This command is used to display system messages and/or help files. The
966 single argument it accepts is the name of the file to display. IT IS CASE
967 SENSITIVE. Citadel looks for these files first in the "messages"
968 subdirectory and then in the "help" subdirectory.
970 If the file is found, LISTING_FOLLOWS is returned, followed by a pathname
971 to the file being displayed. Then the message is printed, in format type 0
972 (see MSG0 command for more information on this). If the file is not found,
975 There are some "well known" names of system messages which client software
976 may expect most servers to carry:
978 hello - Welcome message, to be displayed before the user logs in.
979 changepw - To be displayed whenever the user is prompted for a new
980 password. Warns about picking guessable passwords and such.
981 register - Should be displayed prior to the user entering registration.
982 Warnings about not getting access if not registered, etc.
983 help - Main system help file.
984 goodbye - System logoff banner; display when user logs off.
985 roomaccess - Information about how public rooms and different types of
986 private rooms function with regards to access.
987 unlisted - Tells users not to choose to be unlisted unless they're
988 really paranoid, and warns that aides can still see
989 unlisted userlog entries.
991 Citadel provides these for the Citadel Unix text client. They are
992 probably not very useful for other clients:
994 mainmenu - Main menu (when in idiot mode).
999 saveopt - Options to save a message, abort, etc.
1000 entermsg - Displayed just before a message is entered, when in
1004 GNUR (Get Next Unvalidated User)
1006 This command shows the name of a user that needs to be validated. If there
1007 are no unvalidated users, OK is returned. Otherwise, MORE_DATA is returned
1008 along with the name of the first unvalidated user the server finds. All of
1009 the usual ERROR codes may be returned as well (for example, if the user is
1010 not an Aide and cannot validate users).
1012 A typical "Validate New Users" command would keep executing this command,
1013 and then validating each user it returns, until it returns OK when all new
1014 users have been validated.
1017 GREG (Get REGistration for user)
1019 This command retrieves the registration info for a user, whose name is the
1020 command's sole argument. All the usual error messages can be returned. If
1021 the command succeeds, LISTING_FOLLOWS is returned, followed by the user's name
1022 (retrieved from the userlog, with the right upper and lower case etc.) The
1023 contents of the listing contains one field per line, followed by the usual
1024 000 on the last line.
1026 The following lines are defined. Others WILL be added in the futre, so all
1027 software should be written to read the lines it knows about and then ignore
1028 all remaining lines:
1033 Line 4: Street address or PO Box
1034 Line 5: City/town/village/etc.
1035 Line 6: State/province/etc.
1037 Line 8: Telephone number
1038 Line 9: Access level
1039 Line 10: Internet e-mail address
1042 Users without Aide privileges may retrieve their own registration using
1043 this command. This can be accomplished either by passing the user's own
1044 name as the argument, or the string "_SELF_". The command will always
1045 succeed when used in this manner, unless no user is logged in.
1048 VALI (VALIdate user)
1050 This command is used to validate users. Obviously, it can only be executed
1051 by users with Aide level access. It should be passed two parameters: the
1052 name of the user to validate, and the desired access level
1054 If the command succeeds, OK is returned. The user's access level is changed
1055 and the "need validation" bit is cleared. If the command fails for any
1056 reason, ERROR, ERROR+NO_SUCH_USER, or ERROR+HIGHER_ACCESS_REQUIRED will be
1060 EINF (Enter INFo file for room)
1062 Transmit the info file for the current room with this command. EINF uses
1063 a boolean flag (1 or 0 as the first and only argument to the command) to
1064 determine whether the client actually wishes to transmit a new info file, or
1065 is merely checking to see if it has permission to do so.
1067 If the command cannot succeed, it returns ERROR.
1068 If the client is only checking for permission, and permission will be
1069 granted, OK is returned.
1070 If the client wishes to transmit the new info file, SEND_LISTING is
1071 returned, and the client should transmit the text of the info file, ended
1072 by the usual 000 on a line by itself.
1077 This is a simple user listing. It always succeeds, returning
1078 LISTING_FOLLOWS followed by zero or more user records, 000 terminated. The
1079 fields on each line are as follows:
1084 4. Date/time of last login (Unix format)
1087 7. Password (listed only if the user requesting the list is an Aide)
1089 Unlisted entries will also be listed to Aides logged into the server, but
1090 not to ordinary users.
1092 The LIST command accepts an optional single argument, which is a simple,
1093 case-insensitive search string. If this argument is present, only usernames
1094 in which the search string is present will be returned. It is a simple
1095 substring search, not a regular expression search. If this string is empty
1096 or not present, all users will be returned.
1099 REGI (send REGIstration)
1101 Clients will use this command to transmit a user's registration info. If
1102 no user is logged in, ERROR+NOT_LOGGED_IN is returned. Otherwise,
1103 SEND_LISTING is returned, and the server will expect the following information
1104 (terminated by 000 on a line by itself):
1107 Line 2: Street address or PO Box
1108 Line 3: City/town/village/etc.
1109 Line 4: State/province/etc.
1111 Line 6: Telephone number
1112 Line 7: e-mail address
1116 CHEK (CHEcK various things)
1118 When logging in, there are various things that need to be checked. This
1119 command will return ERROR+NOT_LOGGED_IN if no user is logged in. Otherwise
1120 it returns OK and the following parameters:
1122 0: Number of new private messages in Mail>
1123 1: Nonzero if the user needs to register
1124 2: (Relevant to Aides only) Nonzero if new users require validation
1125 3: The user's preferred Internet e-mail address
1128 DELF (DELete a File)
1130 This command deletes a file from the room's directory, if there is one. The
1131 name of the file to delete is the only parameter to be supplied. Wildcards
1132 are not acceptable, and any slashes in the filename will be converted to
1133 underscores, to prevent unauthorized access to neighboring directories. The
1134 possible return codes are:
1136 OK - Command succeeded. The file was deleted.
1137 ERROR+NOT_LOGGED_IN - Not logged in.
1138 ERROR+HIGHER_ACCESS_REQUIRED - Not an Aide or Room Aide.
1139 ERROR+NOT_HERE - There is no directory in this room.
1140 ERROR+FILE_NOT_FOUND - Requested file was not found.
1145 This command is similar to DELF, except that it moves a file (and its
1146 associated file description) to another room. It should be passed two
1147 parameters: the name of the file to move, and the name of the room to move
1148 the file to. All of the same return codes as DELF may be returned, and also
1149 one additional one: ERROR+NO_SUCH_ROOM, which means that the target room
1150 does not exist. ERROR+NOT_HERE could also mean that the target room does
1151 not have a directory.
1154 NETF (NETwork send a File)
1156 This command is similar to MOVF, except that it attempts to send a file over
1157 the network to another system. It should be passed two parameters: the name
1158 of the file to send, and the node name of the system to send it to. All of
1159 the same return codes as MOVF may be returned, except for ERROR+NO_SUCH_ROOM.
1160 Instead, ERROR+NO_SUCH_SYSTEM may be returned if the name of the target
1163 The name of the originating room will be sent along with the file. Most
1164 implementations will look for a room with the same name at the receiving end
1165 and attempt to place the file there, otherwise it goes into a bit bucket room
1166 for miscellaneous files. This is, however, beyond the scope of this document;
1167 see elsewhere for more details.
1170 RWHO (Read WHO's online)
1172 Displays a list of all users connected to the server. No error codes are
1173 ever returned. LISTING_FOLLOWS will be returned, followed by zero or more
1174 lines containing the following three fields:
1176 0 - Session ID. Citadel fills this with the pid of a server program.
1178 2 - The name of the room the user is currently in. This field might not
1179 be displayed (for example, if the user is in a private room) or it might
1180 contain other information (such as the name of a file the user is
1182 3 - (server v4.03 and above) The name of the host the client is connecting
1183 from, or "localhost" if the client is local.
1184 4 - (server v4.04 and above) Description of the client software being used
1185 5 - The last time, locally to the server, that a command was received from
1186 this client (Note: NOOP's don't count)
1187 6 - The last command received from a client. (NOOP's don't count)
1188 7 - Session flags. These are: + (spoofed address), - (STEALTH mode), *
1189 (posting) and . (idle).
1190 8 - Actual user name, if user name is masqueraded and viewer is an Aide.
1191 9 - Actual room name, if room name is masqueraded and viewer is an Aide.
1192 10 - Actual host name, if host name is masqueraded and viewer is an Aide.
1193 11 - Nonzero if the session is a logged-in user, zero otherwise.
1195 The listing is terminated, as always, with the string "000" on a line by
1199 OPEN (OPEN a file for download)
1201 This command is used to open a file for downloading. Only one download
1202 file may be open at a time. The only argument to this command is the name
1203 of the file to be opened. The user should already be in the room where the
1204 file resides. Possible return codes are:
1207 ERROR+NOT_HERE (no directory in this room)
1208 ERROR+FILE_NOT_FOUND (could not open the file)
1212 If the file is successfully opened, OK will be returned, along with the
1213 size (in bytes) of the file, the time of last modification (if applicable),
1214 the filename (if known), and the MIME type of the file (if known).
1217 CLOS (CLOSe the download file)
1219 This command is used to close the download file. It returns OK if the
1220 file was successfully closed, or ERROR if there wasn't any file open in the
1224 READ (READ from the download file)
1226 Two arguments are passed to this command. The first is the starting position
1227 in the download file, and the second is the total number of bytes to be
1228 read. If the operation can be performed, BINARY_FOLLOWS will be returned,
1229 along with the number of bytes to follow. Then, immediately following the
1230 newline, will be that many bytes of binary data. The client *must* read
1231 exactly that number of bytes, otherwise the client and server will get out
1234 If the operation cannot be performed, any of the usual error codes will be
1238 UOPN (OPeN a file for Uploading)
1240 This command is similar to OPEN, except that this one is used when the
1241 client wishes to upload a file to the server. The first argument is the name
1242 of the file to create, and the second argument is a one-line comment
1243 describing the contents of the file. Only one upload file may be open at a
1244 time. Possible return codes are:
1247 ERROR+NOT_HERE (no directory in this room)
1248 ERROR+FILE_NOT_FOUND (a name must be specified)
1249 ERROR (miscellaneous errors)
1250 ERROR+ALREADY_EXISTS (a file with the same name already exists)
1253 If OK is returned, the command has succeeded and writes may be performed.
1256 UCLS (CLoSe the Upload file)
1258 Close the file opened with UOPN. An argument of "1" should be passed to
1259 this command to close and save the file; otherwise, the transfer will be
1260 considered aborted and the file will be deleted. This command returns OK
1261 if the operation succeeded or ERROR if it did not.
1264 WRIT (WRITe to the upload file)
1266 If an upload file is open, this command may be used to write to it. The
1267 argument passed to this command is the number of bytes the client wishes to
1268 transmit. An ERROR code will be returned if the operation cannot be
1271 If the operation can be performed, SEND_BINARY will be returned, followed
1272 by the number of bytes the server is expecting. The client must then transmit
1273 exactly that number of bytes. Note that in the current implementation, the
1274 number of bytes the server is expecting will always be the number of bytes
1275 the client requested to transmit, but the client software should never assume
1276 that this will always happen, in case changes are made later.
1279 QUSR (Query for a USeR)
1281 This command is used to check to see if a particular user exists. The only
1282 argument to this command is the name of the user being searched for. If
1283 the user exists, OK is returned, along with the name of the user in the userlog
1284 (so the client software can learn the correct upper/lower casing of the name
1285 if necessary). If the user does not exist, ERROR+NO_SUCH_USER is returned.
1286 No login or current room is required to utilize this command.
1289 OIMG (Open an IMaGe file)
1291 Open an image (graphics) file for downloading. Once opened, the file can be
1292 read as if it were a download file. This implies that an image and a download
1293 cannot be opened at the same time. OIMG returns the same result codes as OPEN.
1295 All images will be in GIF (Graphics Interchange Format). In the case of
1296 Citadel, the server will convert the supplied filename to all lower case,
1297 append the characters ".gif" to the filename, and look for it in the "images"
1298 subdirectory. As with the MESG command, there are several "well known"
1299 images which are likely to exist on most servers:
1301 hello - "Welcome" graphics to be displayed alongside MESG "hello"
1302 goodbye - Logoff banner graphics to be displayed alongside MESG "goodbye"
1303 background - Background image (usually tiled) for graphical clients
1305 The following "special" image names are defined in Citadel server version
1308 _userpic_ - Picture of a user (send the username as the second argument)
1309 _floorpic_ - A graphical floor label (send the floor number as the second
1310 argument). Clients which request a floor picture will display
1311 the picture *instead* of the floor name.
1312 _roompic_ - A graphic associated with the *current* room. Clients which
1313 request a room picture will display the picture in *addition*
1314 to the room name (i.e. it's used for a room banner, as
1315 opposed to the floor picture's use in a floor listing).
1318 NETP (authenticate as network session with connection NET Password)
1320 This command is used by client software to identify itself as a transport
1321 session for Citadel site-to-site networking. It should be called with
1322 two arguments: the node name of the calling system, and the "shared secret"
1323 password for that connection. If the authentication succeeds, NETP will
1324 return OK, otherwise, it returns ERROR.
1327 NSYN (Network SYNchronize room)
1329 This command can be used to synchronize the contents of a room on the
1330 network. It is only usable by Aides. It accepts one argument: the name of
1331 a network node (which must be a valid one).
1333 When NSYN is run, the *entire* contents of the current room will be spooled
1334 to the specified node, without regard to whether any of the messages have
1335 already undergone network processing. It is up to the receiving node to
1336 check for duplicates (the Citadel networker does handle this) and avoid
1339 The command returns OK upon success or ERROR if the user is not an Aide.
1342 NUOP (Network Upload OPen file)
1344 Open a network spool file for uploading. The client must have already
1345 identified itself as a network session using the NETP command. If the command
1346 returns OK, the client may begin transmitting IGnet/Open spool data using
1347 a series of WRIT commands. When a UCLS command is issued, the spooled data
1348 is entered into the server if the argument to UCLS is 1 or discarded if the
1349 argument to UCLS is 0. If the client has not authenticated itself with a
1350 NETP command, ERROR+HIGHER_ACCESS_REQUIRED will be returned.
1353 NDOP (Network Download OPen file)
1355 Open a network spool file for downloading. The client must have already
1356 identified itself as a network session using the NETP command. If the command
1357 returns OK, the client may begin receiving IGnet/Open spool data using
1358 a series of READ commands. When a CLOS command is issued, the spooled data
1359 is deleted from the server and may not be read again. If the client has not
1360 authenticated itself with a NETP command, ERROR+HIGHER_ACCESS_REQUIRED will
1364 LFLR (List all known FLooRs)
1366 On systems supporting floors, this command lists all known floors. The
1367 command accepts no parameters. It will return ERROR+NOT_LOGGED_IN if no
1368 user is logged in. Otherwise it returns LISTING_FOLLOWS and a list of
1369 the available floors, each line consisting of three fields:
1371 1. The floor number associated with the floor
1372 2. The name of the floor
1373 3. Reference count (number of rooms on this floor)
1376 CFLR (Create a new FLooR)
1378 This command is used to create a new floor. It should be passed two
1379 arguments: the name of the new floor to be created, and a 1 or 0 depending
1380 on whether the client is actually creating a floor or merely checking to
1381 see if it has permission to create the floor. The user must be logged in
1382 and have Aide privileges to create a floor.
1384 If the command succeeds, it will return OK followed by the floor number
1385 associated with the new floor. Otherwise, it will return ERROR (plus perhaps
1386 HIGHER_ACCESS_REQUIRED, ALREADY_EXISTS, or INVALID_FLOOR_OPERATION)
1387 followed by a description of why the command failed.
1392 This command is used to delete a floor. It should be passed two
1393 argument: the *number* of the floor to be deleted, and a 1 or 0 depending
1394 on whether the client is actually deleting the floor or merely checking to
1395 see if it has permission to delete the floor. The user must be logged in
1396 and have Aide privileges to delete a floor.
1398 Floors that contain rooms may not be deleted. If there are rooms on a floor,
1399 they must be either deleted or moved to different floors first. This implies
1400 that the Main Floor (floor 0) can never be deleted, since Lobby>, Mail>, and
1401 Aide> all reside on the Main Floor and cannot be deleted.
1403 If the command succeeds, it will return OK. Otherwise it will return
1404 ERROR (plus perhaps HIGHER_ACCESS_REQUIRED or INVALID_FLOOR_OPERATION)
1405 followed by a description of why the command failed.
1410 Edit the parameters of a floor. The client may pass one or more parameters
1413 1. The number of the floor to be edited
1414 2. The desired new name
1416 More parameters may be added in the future. Any parameters not passed to
1417 the server will remain unchanged. A minimal command would be EFLR and a
1418 floor number -- which would do nothing. EFLR plus the floor number plus a
1419 floor name would change the floor's name.
1421 If the command succeeds, it will return OK. Otherwise it will return
1422 ERROR (plus perhaps HIGHER_ACCESS_REQUIRED or INVALID_FLOOR_OPERATION)
1425 IDEN (IDENtify the client software)
1427 The client software has the option to identify itself to the server.
1428 Currently, the server does nothing with this information except to write
1429 it to the syslog to satisfy the system administrator's curiosity. Other
1430 uses might become apparent in the future.
1432 The IDEN command should contain five fields: a developer ID number (same as
1433 the server developer ID numbers in the INFO command -- please obtain one if
1434 you are a new developer), a client ID number (which does not have to be
1435 globally unique - only unique within the domain of the developer number),
1436 a version number, a free-form text string describing the client, and the name
1437 of the host the user is located at.
1439 It is up to the server to determine whether to accept the host name or to
1440 use the host name it has detected itself. Generally, if the client is
1441 running on a trusted host (either localhost or a well-known publically
1442 accessible client) it should use the host name transmitted by IDEN,
1443 otherwise it should use the host name it has detected itself.
1445 IDEN always returns OK, but since that's the only way it ever returns
1446 there's no point in checking the result code.
1449 IPGM (identify as an Internal ProGraM)
1451 IPGM is a low-level command that should not be used by normal user clients.
1452 It is used for various utilities to communicate with the server on the same
1453 host. For example, the "sendcommand" utility logs onto the server as an
1454 internal program in order to run arbitrary server commands. Since user clients
1455 do not utilize this command (or any of its companion commands), developers
1456 writing Citadel-compatible servers need not implement it.
1458 The sole argument to IPGM is the system's internal program password. This
1459 password is generated by the setup program and stored in the config file.
1460 Since internal programs have access to the config file, they know the correct
1463 IPGM returns OK for a correct authentication or ERROR otherwise.
1466 CHAT (enter CHAT mode)
1468 This command functions differently from every other command in the system. It
1469 is used to implement multi-user chat. For this to function, a new transfer
1470 mode, called START_CHAT_MODE, is implemented. If a client does not support
1471 chat mode, it should never send a CHAT command!
1473 In chat mode, messages may arrive asynchronously from the server at any
1474 time. The client may send messages at any time. This allows the arrival of
1475 messages without the client having to poll for them. Arriving messages will
1476 be of the form "user|message", where the "user" portion is, of course, the
1477 name of the user sending the message, and "message" is the message text.
1479 Chat mode ends when the server says it ends. The server will signal the end
1480 of chat mode by transmitting "000" on a line by itself. When the client reads
1481 this line, it must immediately exit from chat mode without sending any
1482 further traffic to the server. The next transmission sent to the server
1483 will be a regular server command.
1485 The Citadel server understands the following commands:
1486 /quit - Exit from chat mode (causes the server to do an 000 end)
1487 /who - List users currently in chat
1488 /whobbs - List users currently in chat and elsewhere
1489 /me - Do an irc-style action.
1490 /join - Join a new "room" in which all messages are only heard by
1491 people in that room.
1492 /msg - /msg <user> <msg> will send the msg to <user> only.
1493 /help - Print help information
1494 NOOP - Do nothing (silently)
1496 Any other non-empty string is treated as message text and will be broadcast
1497 to other users currently in chat.
1500 SEXP (Send instant message)
1502 This is one of two commands which implement instant messages (also known
1503 as "paging"). Commands ending in "...EXP" are so-named because we called
1504 them "express messages" before the industry standardized on the term
1505 "instant messages." When an instant message is sent, it will be
1506 logged in user to another. When an instant message is sent, it will be
1507 displayed the next time the target user executes a PEXP or GEXP command.
1509 The SEXP command accepts two arguments: the name of the user to send the
1510 message to, and the text of the message. If the message is successfully
1511 transmitted, OK is returned. If the target user is not logged in or if
1512 anything else goes wrong, ERROR is returned.
1514 If the server supports extended paging, sending a zero-length message
1515 merely checks for the presence of the requested user without actually sending
1516 a message. Sending a message consisting solely of a "-" (hyphen) will cause
1517 the server to return SEND_LISTING if the requested user is logged in, and the
1518 client can then transmit a multi-line page.
1520 The reserved name "broadcast" may be used instead of a user name, to
1521 broadcast an instant message to all users currently connected to the server.
1523 Do be aware that if an instant message is transmitted to a user who is logged
1524 in using a client that does not check for instant messages, the message will
1525 never be received. Also, instant messages are NOT sent via the following
1526 transports: SMTP, POP3.
1529 PEXP (Print instant messages) ***DEPRECATED***
1531 This command is deprecated; it will eventually disappear from the protocol and
1532 its use is not recommended. Please use the GEXP command instead.
1534 Called without any arguments, PEXP simply dumps out the contents
1535 of any waiting instant messages. It returns ERROR if there is a problem,
1536 otherwise it returns LISTING_FOLLOWS followed by all messages.
1538 So how does the client know there are instant messages waiting? It could
1539 execute a random PEXP every now and then. Or, it can check the byte in
1540 server return code messages, between the return code and the parameters. In
1541 much the same way as FTP uses "-" to signify a continuation, Citadel uses
1542 an "*" in this position to signify the presence of waiting instant messages.
1545 EBIO (Enter BIOgraphy)
1547 Transmit to the server a free-form text file containing a little bit of
1548 information about the user for other users to browse. This is typically
1549 referred to as a 'bio' online. EBIO returns SEND_LISTING if it succeeds,
1550 after which the client is expected to transmit the file, or any of the usual
1551 ERROR codes if it fails.
1554 RBIO (Read BIOgraphy)
1556 Receive from the server a named user's bio. This command should be passed
1557 a single argument - the name of the user whose bio is requested. RBIO returns
1558 LISTING_FOLLOWS plus the bio file if the user exists and has a bio on file.
1559 The return has the following parameters: the user name, user number, access
1560 level, date of last call, times called, and messages posted. This command
1561 returns ERROR+NO_SUCH_USER if the named user does not exist.
1563 RBIO no longer considers a user with no bio on file to be an error condition.
1564 It now returns a message saying the user has no bio on file as the text of the
1565 bio. This allows newer servers to operate with older clients.
1568 STEL (enter STEaLth mode)
1570 When in "stealth mode," a user will not show up in the "Who is online"
1571 listing (the RWHO server command). Only Aides may use stealth mode. The
1572 STEL command accepts one argument: a 1 indicating that the user wishes to
1573 enter stealth mode, or a 0 indicating that the user wishes to exit stealth
1574 mode. STEL returns OK if the command succeeded, ERROR+NOT_LOGGED_IN if no
1575 user is logged in, or ERROR+HIGHER_ACCESS_REQUIRED if the user is not an Aide;
1576 followed by a 1 or 0 indicating the new state.
1578 If any value other than 1 or 0 is sent by the client, the server simply
1579 replies with 1 or 0 to indicate the current state without changing it.
1581 The STEL command also makes it so a user does not show up in the chat room
1585 LBIO (List users who have BIOs on file)
1587 This command is self-explanatory. Any user who has used EBIO to place a bio
1588 on file is listed. LBIO almost always returns LISTING_FOLLOWS followed by
1589 this listing, unless it experiences an internal error in which case ERROR
1593 MSG2 (read MeSsaGe, mode 2)
1595 MSG2 follows the same calling convention as MSG0. The difference between
1596 the two commands is that MSG2 outputs messages in standard RFC822 format
1597 rather than in Citadel proprietary format.
1599 This command was implemented in order to make various gateway programs
1600 easier to implement, and to provide some sort of multimedia support in the
1601 future. Keep in mind that when this command is used, all messages will be
1602 output in fixed 80-column format.
1605 MSG3 (read MeSsaGe, mode 3 -- internal command)
1607 MSG3 is for use by internal programs only and should not be utilized by
1608 user-mode clients. It does require IPGM authentication. MSG3 follows the
1609 same calling convention as the other MSG commands, but upon success returns
1610 BINARY_FOLLOWS followed by a data block containing the _raw_ message format
1614 TERM (TERMinate another session)
1616 In a multithreaded environment, it sometimes becomes necessary to terminate
1617 a session that is unusable for whatever reason. The TERM command performs
1618 this task. Naturally, only Aides can execute TERM. The command should be
1619 called with a single argument: the session ID (obtained from an RWHO command)
1620 of the session to be terminated.
1622 TERM returns OK if the session was terminated, or ERROR otherwise. Note that
1623 a client program is prohibited from terminating the session it is currently
1629 DOWN (shut DOWN the server)
1631 This command, which may only be executed by an Aide, immediately shuts down
1632 the server. It is only implemented on servers on which such an operation is
1633 possible, such as a multithreaded Citadel engine. The server does not restart.
1634 DOWN returns OK if the user is allowed to shut down the server, in which case
1635 the client program should expect the connection to be immediately broken.
1638 SCDN (Schedule or Cancel a shutDowN)
1640 SCDN sets or clears the "scheduled shutdown" flag. Pass this command a 1 or
1641 0 to respectively set or clear the flag. When the "scheduled shutdown" flag is
1642 set, the server will be shut down when there are no longer any users logged in.
1643 Any value other than 0 or 1 will not change the flag, only report its state.
1644 No users will be kicked off the system, and in fact the server is still
1645 available for new connections. The command returns ERROR if it fails;
1646 otherwise, it returns OK followed by a number representing the current state
1650 EMSG (Enter a system MeSsaGe)
1652 This is the opposite of the MESG command - it allows the creation and editing
1653 of system messages. The only argument passed to EMSG is the name of the
1654 file being transmitted. If the file exists in any system message directory
1655 on the server it will be overwritten, otherwise a new file is created. EMSG
1656 returns SEND_LISTING on success or ERROR+HIGHER_ACCESS_REQUIRED if the user
1659 Typical client software would use MESG to retrieve any existing message into
1660 an edit buffer, then present an editor to the user and run EMSG if the changes
1664 UIMG (Upload an IMaGe file)
1666 UIMG is complemenary to OIMG; it is used to upload an image to the server.
1667 The first parameter supplied to UIMG should be 0 if the client is only checking
1668 for permission to upload, or 1 if the client is actually attempting to begin
1669 the upload operation. The second argument is the name of the file to be
1670 transmitted. In Citadel, the filename is converted to all lower case,
1671 appended with the characters ".gif", and stored in the "images" directory.
1673 UIMG returns OK if the client has permission to perform the requested upload,
1674 or ERROR+HIGHER_ACCESS_REQUIRED otherwise. If the client requested to begin
1675 the operation (first parameter set to 1), an upload file is opened, and the
1676 client should begin writing to it with WRIT commands, then close it with a
1679 The supplied filename should be one of:
1681 -> _userpic_ (Server will attempt to write to the user's online photo)
1682 -> Any of the "well known" filenames described in the writeup for the
1686 HCHG (Hostname CHanGe)
1688 HCHG is a command, usable by any user, that allows a user to change their RWHO
1689 host value. This will mask a client's originating hostname from normal
1690 users; access level 6 and higher can see, in an extended wholist, the actual
1691 hostname the user originates from.
1693 The format of an HCHG command is:
1697 If a HCHG command is successful, the value OK (200) is returned.
1700 RCHG (Roomname CHanGe)
1702 RCHG is a command, usable by any user, that allows a user to change their RWHO
1703 room value. This will mask a client's roomname from normal users; access
1704 level 6 and higher can see, in an extended wholist, the actual room the user
1707 The format of an RCHG command is:
1711 If a RCHG command is successful, the value OK (200) is returned.
1714 UCHG (Username CHanGe)
1716 UCHG is an aide-level command which allows an aide to effectively change their
1717 username. If this value is blank, the user goes into stealth mode (see
1719 will show up as being from the real username in this mode, however. In
1720 addition, the RWHO listing will include both the spoofed and real usernames.
1722 The format of an UCHG command is:
1726 If a UCHG command is successful, the value OK (200) is returned.
1729 TIME (get server local TIME)
1731 TIME returns OK followed by the current time measured in seconds since
1732 00:00:00 GMT, Jan 1, 1970 (standard Unix format).
1734 This is used in allowing a client to calculate idle times.
1737 AGUP (Administrative Get User Parameters)
1738 ASUP (Administrative Set User Parameters)
1740 These commands are only executable by Aides and by server extensions running
1741 at system-level. They are used to get/set any and all parameters relating to
1742 a user account. AGUP requires only one argument: the name of the user in
1743 question. SGUP requires all of the parameters to be set. The parameters are
1744 as follows, and are common to both commands:
1748 2 - Flags (see citadel.h)
1753 7 - Timestamp of last call
1754 8 - Purge time (in days) for this user (or 0 to use system default)
1756 Upon success, AGUP returns OK followed by all these parameters, and ASUP
1757 simply returns OK. If the client has insufficient access to perform the
1758 requested operation, ERROR+HIGHER_ACCESS_REQUIRED is returned. If the
1759 requested user does not exist, ERROR+NO_SUCH_USER is returned.
1763 GPEX (Get Policy for message EXpiration)
1765 Returns the policy of the current room, floor, or site regarding the automatic
1766 purging (expiration) of messages. The following policies are available:
1767 0 - Fall back to the policy of the next higher level. If this is a room,
1768 use the floor's default policy. If this is a floor, use the system
1769 default policy. This is an invalid value for the system policy.
1770 1 - Do not purge messages automatically.
1771 2 - Purge by message count. (Requires a value: number of messages)
1772 3 - Purge by message age. (Requires a value: number of days)
1774 The format of this command is: GPEX <which>
1775 The value of <which> must be one of: "room" "floor" "site" "mailboxes"
1777 If successful, GPEX returns OK followed by <policy>|<value>.
1781 SPEX (Set Policy for message EXpiration)
1783 Sets the policy of the current room, floor, or site regarding the automatic
1784 purging (expiration) of messages. See the writeup for the GPEX command for
1785 the list of available policies.
1787 The format of this command is: SPEX <which>|<policy>|<value>
1788 The value of <which> must be one of: "room" "floor" "site" "mailboxes"
1790 If successful, GPEX returns OK; otherwise, an ERROR code is returned.
1794 CONF (get or set global CONFiguration options)
1796 Retrieves or sets various system-wide configuration and policy options. This
1797 command is only available to Aides. The sole parameter accepted is a command,
1798 which should be either GET or SET. If the GET command succeeds, CONF will
1799 return LISTING_FOLLOWS followed by the fields described below, one line at a
1800 time. If the SET command succeeds, CONF will return SEND_LISTING and expect
1801 the fields described below, one line at a time (don't worry about other fields
1802 being added in the future; if a 'short' configuration list is sent, the missing
1803 values at the end will be left unchanged on the system). If either command
1804 fails for any reason, ERROR is returned.
1806 The configuration lines are as follows:
1809 2. Fully qualified domain name
1810 3. Human-readable node name
1811 4. Landline telephone number of this system
1812 5. Flag (0 or 1) - creator of private room automatically becomes room aide
1813 6. Server connection idle timeout (in seconds)
1814 7. Initial access level for new users
1815 8. Flag (0 or 1) - require registration for new users
1816 9. Flag (0 or 1) - automatically move Problem User messages to twit room
1817 10. Name of twit room
1818 11. Text of <more> prompt
1819 12. Flag (0 or 1) - restrict access to Internet mail
1820 13. Geographic location of this system
1821 14. Name of the system administrator
1822 15. Number of maximum concurrent sessions allowed on the server
1823 16. (placeholder -- this field is no longer in use)
1824 17. Default purge time (in days) for users
1825 18. Default purge time (in days) for rooms
1826 19. Name of room to log instant messages to (or a zero-length name for none)
1827 20. Access level required to create rooms
1828 21. Maximum message length which may be entered into the system
1829 22. Minimum number of worker threads
1830 23. Maximum number of worker threads
1831 24. Port number for POP3 service
1832 25. Port number for SMTP service
1833 26. Flag (0 or 1) - strict RFC822 adherence - don't correct From: forgeries
1834 27. Flag (0 or 1) - allow Aides to zap (forget) rooms
1835 28. Port number for IMAP service
1836 29. How often (in seconds) to run the networker
1837 30. Flag (0 or 1) - disable self-service new user registration
1838 31. (placeholder -- this field is no longer in use)
1839 32. Hour (0 through 23) during which database auto-purge jobs are run
1840 33. Name of host where an LDAP service may be found
1841 34. Port number of LDAP service on above host
1844 37. Password for LDAP Bind DN
1845 38. Server IP address to listen on (or "0.0.0.0" for all addresses)
1846 39. Port number for SMTP MSA service
1847 40. Port number for IMAPS (SSL-encrypted IMAP)
1848 41. Port number for POP3S (SSL-encrypted POP3)
1849 42. Port number for SMTPS (SSL-encrypted SMTP)
1850 43. Flag (0 or 1) - enable full text search index
1851 44. Flag (0 or 1) - automatically cull database log files
1852 45. Flag (0 or 1) - enable IMAP "instant expunge" of deleted messages
1853 46. Flag (0 or 1) - allow unauthenticated SMTP clients to spoof my domains
1855 CONF also accepts two additional commands: GETSYS and PUTSYS followed by an
1856 arbitrary MIME type (such as application/x-citadel-internet-config) which
1857 provides a means of storing generic configuration data in the Global System
1858 Configuration room without the need to add extra get/set commands to the
1861 Please note that the LDAP-specific configs have no effect on Citadel servers
1862 in which LDAP support is not enabled.
1866 MSG4 (read MeSsaGe, mode 4 -- output in preferred MIME format)
1868 This is the equivalent of MSG0, except it's a bit smarter about messages in
1869 rich text formats. Immediately following the "text" directive, the server
1870 will output RFC822-like MIME part headers such as "Content-type:" and
1871 "Content-length:". MIME formats are chosen and/or converted based on the
1872 client's preferred format settings, which are set using the MSGP command,
1877 MSGP (set MeSsaGe Preferred MIME format)
1879 Client tells the server what MIME content types it knows how to handle, and
1880 the order in which it prefers them. This is similar to an HTTP "Accept:"
1883 The parameters to a MSGP command are the client's acceptable MIME content
1884 types, in the order it prefers them (from most preferred to least preferred).
1885 For example: MSGP text/html|text/plain
1887 The MSGP command always returns OK.
1891 OPNA (OPeN Attachment)
1893 Opens, as a download file, a component of a MIME-encoded message. The two
1894 parameters which must be passed to this command are the message number and the
1895 name of the desired section. If the message or section does not exist, an
1896 appropriate ERROR code will be returned; otherwise, if the open is successful,
1897 this command will succeed returning the same information as an OPEN command.
1900 GEXP (Get instant messages)
1902 This is a more sophisticated way of retrieving instant messages than the old
1903 PEXP method. If there are no instant messages waiting, PEXP returns ERROR;
1904 otherwise, it returns LISTING_FOLLOWS and the following arguments:
1906 0 - a boolean value telling the client whether there are any additional
1907 instant messages waiting following this one
1908 1 - a Unix-style timestamp
1909 2 - flags (see server.h for more info)
1910 3 - the name of the sender
1911 4 - the node this message originated on (for future support of PIP, ICQ, etc.)
1913 The text sent to the client will be the body of the instant message.
1915 So how does the client know there are instant messages waiting? It could
1916 execute a random GEXP every now and then. Or, it can check the byte in
1917 server return code messages, between the return code and the parameters. In
1918 much the same way as FTP uses "-" to signify a continuation, Citadel uses
1919 an "*" in this position to signify the presence of waiting instant messages.
1922 FSCK (check message base reference counts)
1924 Verify, via the long way, that all message referenmce counts are correct. If
1925 the user has permission to do this then LISTING_FOLLOWS is returned, followed
1926 by a transcript of the run. Otherwise ERROR is returned.
1929 DEXP (Disable receiving instant messages)
1931 DEXP sets or clears the "disable instant messages" flag. Pass this command a
1932 1 or 0 to respectively set or clear the flag. When the "disable instant
1933 messages" flag is set, no one except Aides may send the user instant messages.
1934 Any value other than 0 or 1 will not change the flag, only report its state.
1935 The command returns ERROR if it fails; otherwise, it returns OK followed by a
1936 number representing the current state of the flag.
1939 REQT (REQuest client Termination)
1941 Request that the specified client (or all clients) log off. Aide level
1942 access is required to run this command, otherwise ERROR+HIGHER_ACCESS_REQUIRED
1945 The REQT command accepts one parameter: the session ID of the client which
1946 should be terminated, or 0 for all clients. When successful, the REQT command
1949 It should be noted that REQT simply transmits an instant message to the
1950 specified client(s) with the EM_GO_AWAY flag set. Older clients do not honor
1951 this flag, and it is certainly possible for users to re-program their client
1952 software to ignore it. Therefore the effects of the REQT command should be
1953 considered advisory only. The recommended implementation practice is to first
1954 issue a REQT command, then wait a little while (from 30 seconds up to a few
1955 minutes) for well-behaved clients to voluntarily terminate, and then issue a
1956 TERM command to forcibly disconnect the client (or perhaps a DOWN command, if
1957 you are logging off users for the purpose of shutting down the server).
1960 SEEN (set or clear the SEEN flag for a message)
1962 Beginning with version 5.80, Citadel supports the concept of setting or
1963 clearing the "seen" flag for each individual message, instead of only allowing
1964 a "last seen" pointer. In fact, the old semantics are implemented in terms
1965 of the new semantics. This command requires two arguments: the number of the
1966 message to be set, and a 1 or 0 to set or clear the "seen" bit.
1968 This command returns OK, unless the user is not logged in or a usage error
1969 occurred, in which case it returns ERROR. Please note that no checking is
1970 done on the supplied data; if the requested message does not exist, the SEEN
1971 command simply returns OK without doing anything.
1974 GTSN (GeT the list of SeeN messages)
1976 This command retrieves the list of "seen" (as opposed to unread) messages for
1977 the current room. It returns OK followed by an IMAP-format message list.
1980 SMTP (utility commands for the SMTP gateway)
1982 This command, accessible only by Aides, supports several utility operations
1983 which examine or manipulate Citadel's SMTP support. The first command argument
1984 is a subcommand telling the server what to do. The following subcommands are
1987 SMTP mx|hostname (display all MX hosts for 'hostname')
1988 SMTP runqueue (attempt immediate delivery of all messages
1989 in the outbound SMTP queue, ignoring any
1990 retry times stored there)
1993 STLS (Start Transport Layer Security)
1995 This command starts TLS on the current connection. The current
1996 implementation uses OpenSSL on both the client and server end. For future
1997 compatibility all clients must support at least TLSv1, and servers are
1998 guaranteed to support TLSv1. During TLS negotiation (see below) the server
1999 and client may agree to use a different protocol.
2001 The server returns ERROR if it does not support SSL or SSL initialization
2002 failed on the server; otherwise it returns OK. Once the server returns OK and
2003 the client has read the response, the server and client immediately negotiate
2004 TLS (in OpenSSL, using SSL_connect() on the client and SSL_accept() on the
2005 server). If negotiation fails, the server and client should attempt to resume
2006 the session unencrypted. If either end is unable to resume the session, the
2007 connection should be closed.
2009 This command may be run at any time.
2012 GTLS (Get Transport Layer Security Status)
2014 This command returns information about the current connection. The server
2015 returns OK plus several parameters if the connection is encrypted, and ERROR
2016 if the connection is not encrypted. It is primarily used for debugging. The
2017 command may be run at any time.
2019 0 - Protocol name, e.g. "SSLv3"
2020 1 - Cipher suite name, e.g. "ADH-RC4-MD5"
2021 2 - Cipher strength bits, e.g. 128
2022 3 - Cipher strength bits actually in use, e.g. 128
2025 IGAB (Initialize Global Address Book)
2027 This command creates, or re-creates, a database of Internet e-mail addresses
2028 using the vCard information in the Global Address Book room. This procedure
2029 is normally run internally when the server determines it necessary, but is
2030 also provided as a server command to be used as a troubleshooting/maintenenance
2031 tool. Only a system Aide can run the command. It returns OK on success or
2035 QDIR (Query global DIRectory)
2037 Look up an internet address in the global directory. Any logged-in user may
2038 call QDIR with one parameter, the Internet e-mail address to look up. QDIR
2039 returns OK followed by a Citadel address if there is a match, otherwise it
2040 returns ERROR+NOT_LOGGED_IN.
2043 ISME (find out if an e-mail address IS ME)
2045 This is a quickie shortcut command to find out if a given e-mail address
2046 belongs to the user currently logged in. Its sole argument is an address to
2047 parse. The supplied address may be in any format (local, IGnet, or Internet).
2048 The command returns OK if the address belongs to the user, ERROR otherwise.
2051 VIEW (set the VIEW for a room)
2053 Set the preferred view for the current user in the current room. Please see
2054 views.txt for more information on views. The sole parameter for this command
2055 is the type of view requested. VIEW returns OK on success or ERROR on failure.
2058 QNOP (Quiet No OPeration)
2060 This command does nothing, similar to the NOOP command. However, unlike the
2061 NOOP command, it returns *absolutely no response* at all. The client has no
2062 way of knowing that the command executed. It is intended for sending
2063 "keepalives" in situations where a full NOOP would cause the client protocol
2066 Naturally, sending this command to a server that doesn't support it is an
2067 easy way to mess things up. Therefore, client software should first check
2068 the output of an INFO command to ensure that the server supports quiet noops.
2072 ICAL (Internet CALendaring commands)
2074 This command supports a number of subcommands which are used to process the
2075 calendaring/scheduling support in Citadel. Here are the subcommands which
2079 Test server for calendaring support. Always returns OK unless the server
2080 does not have the calendar module enabled.
2082 ICAL respond|msgnum|partnum|action
2083 Respond to a meeting request. 'msgnum' and 'partnum' refer to a MIME-encoded
2084 meeting invitation in the current room. 'action' must be set to either
2085 "accept" or "decline" to determine the action to take. This subcommand will
2086 return either OK or ERROR.
2088 ICAL conflicts|msgnum|partnum
2089 Determine whether an incoming VEVENT will fit in the user's calendar by
2090 checking it against the existing VEVENTs. 'msgnum' and 'partnum' refer to
2091 a MIME-encoded meeting invitation in the current room (usually the inbox).
2092 This command may return ERROR if something went wrong, but usually it will
2093 return LISTING_FOLLOWS followed by a list of zero or more conflicting
2094 events. A zero-length list means that there were no conflicts.
2096 ICAL handle_rsvp|msgnum|partnum
2097 Handle an incoming "reply" (or RSVP) to a meeting request you sent out.
2098 'msgnum' and 'partnum' refer to a MIME-encoded reply in the current room.
2099 'action' must be set to either "update" or "ignore" to determine the action
2100 to take. If the action is "update" then the server will hunt for the meeting
2101 in the user's Calendar> room, and update the status for this attendee. Either
2102 way, the reply message is deleted from the current room. This subcommand will
2103 return either OK or ERROR.
2105 ICAL freebusy|username
2106 Output the free/busy times for the requested user. If the user specified
2107 has a calendar available, this command will return LISTING_FOLLOWS and a
2108 compound VCALENDAR object. That object, in turn, will contain VEVENT
2109 objects that have been stripped of all properties except for the bare
2110 minimum needed to learn free/busy times (such as DTSTART, DTEND, and
2111 TRANSP). If there is no such user, or no calendar available, the usual
2112 ERROR codes will be returned.
2116 Readers who are paying attention will notice that there is no subcommand to
2117 send out meeting invitations. This is because that task can be handled
2118 automatically by the Citadel server. Issue this command with <bool> set to 1
2119 to enable Server Generated Invitations. In this mode, when an event is saved
2120 to the user's Calendar> room and it contains attendees, Citadel will
2121 automatically turn the event into vCalendar REQUEST messages and mail them
2122 out to all listed attendees. If for some reason the client needs to disable
2123 Server Generated Invitations, the command may be sent again with <bool> = 0.
2127 MRTG (Multi Router Traffic Grapher)
2129 Multi Router Traffic Grapher (please see http://www.mrtg.org for more info) is
2130 a tool which creates pretty graphs of network activity, usually collected from
2131 routers using SNMP. However, its ability to call external scripts has spawned
2132 a small community of people using it to graph anything which can be graphed.
2133 The MRTG command can output Citadel server activity in the format MRTG expects.
2135 This format is as follows:
2140 Line 3: uptime of system
2141 Line 4: name of system
2144 MRTG accepts two different keywords. "MRTG users" will return two variables,
2145 the number of connected users and the number of active users. "MRTG messages"
2146 will return one variable (and a zero in the second field), showing the current
2147 highest message number on the system. Any other keyword, or a missing keyword,
2148 will cause the MRTG command to return an ERROR code.
2150 Please get in touch with the Citadel developers if you wish to experiment with
2155 GNET (Get NETwork configuration for this room)
2156 SNET (Set NETwork configuration for this room)
2158 These commands get/set the network configuration for the current room. Aide
2159 or Room Aide privileges are required, otherwise an ERROR code is returned.
2160 If the command succeeds, LISTING_FOLLOWS or SEND_LISTING is returned. The
2161 network configuration for a specific room includes neighbor nodes with whom
2162 the room is shared, and mailing list recipients. The format of the network
2163 configuration is described in the file "netconfigs.txt".
2167 ASYN (ASYNchronous message support)
2169 Negotiate the use of asynchronous, or unsolicited, protocol messages. The
2170 only parameter specified should be 1 or 0 to indicate that the client can or
2171 cannot handle this type of messages. The server will reply OK followed by a
2172 1 or 0 to tell the client which mode it is now operating in.
2174 If the command is not available on the server (i.e. it returns ERROR), or
2175 if the command has not been executed by the client, it should be assumed that
2176 this mode of operation is NOT in effect.
2178 The client may also send any value other than 0 or 1 to simply cause the
2179 server to output its current state without changing it.
2181 When asynchronous protocol mode is in effect, the client MUST handle any
2182 asynchronous messages as they arrive, before doing anything else.
2186 SRCH (SeaRCH the message base)
2188 This command's implementation is incomplete and will be documented when it
2189 is finished. The current implementation accepts a search string as its sole
2190 argument, and will respond with LISTING_FOLLOWS followed by a list of
2191 messages (globally, not just in the current room) which contain ALL of the
2192 words in the search string. If the client desires an "exact phrase" match,
2193 it must then slow-search the text of each returned message for the exact
2194 string. The client should also compare the returned message numbers against
2195 those which actually exist in the room or rooms being searched. In
2196 particular, clients should avoid telling the user about messages which exist
2197 only in rooms to which the user does not have access.
2199 Again, keep in mind that this is a temporary implementation and is not
2200 guaranteed to continue to exist in this form.
2205 ASYNCHRONOUS MESSAGES
2206 ---------------------
2208 When the client protocol is operating in asynchronous mode (please refer to
2209 the writeup of the ASYN command above), the following messages may arrive at
2213 902 (instant message arriving)
2215 One or more instant messages have arrived for this client.