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.
45 GENERAL INFORMATION ABOUT THE SERVER
46 ------------------------------------
48 The server is connection-oriented and stateful: each client requires its own
49 connection to a server process, and when a command is sent, the client must
50 read the response, and then transfer data or change modes if necessary.
52 The application layer is very much like other Internet protocols such as SMTP
53 or NNTP. A client program sends one-line commands to the server, and the
54 server responds with a three-digit numeric result code followed by a message
55 describing what happened. This cycle continues until the end of the
58 Unlike protocols such as FTP, all data transfers occur in-band. This means
59 that the same connection that is used for exchange of client/server
60 messages, will also be used to transfer data back and forth. (FTP opens a
61 separate connection for data transfers.) This keeps protocol administration
62 straightforward, as it can traverse firewalls without any special protocol
63 support on the firewall except for opening the port number.
69 The server will respond to all commands with a 3-digit result code, which
70 will be the first three characters on the line. The rest of the line may
71 contain a human-readable string explaining what happened. (Some client
72 software will display some of these strings to the user.)
74 The first digit is the most important. The following codes are defined for
75 this position: ERROR, OK, MORE_DATA, LISTING_FOLLOWS, and SEND_LISTING.
77 The second and third digits may provide a reason as to why a command
78 succeeded or failed. See ipcdef.h for the available codes.
80 ERROR means the command did not complete.
81 OK means the command executed successfully.
82 MORE_DATA means the command executed partially. Usually this means that
83 another command needs to be executed to complete the operation. For example,
84 sending the USER command to log in a user usually results in a MORE_DATA
85 result code, because the client needs to execute a PASS command to send the
86 password and complete the login.
87 LISTING_FOLLOWS means that after the server response, the server will
88 output a listing of some sort. The client *must* read the listing, whether
89 it wants to or not. The end of the listing is signified by the string
90 "000" on a line by itself.
91 SEND_LISTING is the opposite of LISTING_FOLLOWS. It means that the client
92 should begin sending a listing of some sort. The client *must* send something,
93 even if it is an empty listing. Again, the listing ends with "000" on a line
95 BINARY_FOLLOWS and SEND_BINARY mean that the client must immediately send
96 or receive a block of binary data. The first parameter will always be the
98 ASYNC_MESSAGE_FOLLOWS means that an asynchronous, or unsolicited, message
99 follows. The next line will be one of the above codes, and if a data transfer
100 is involved it must be handled immediately. Note that the client will not
101 receive this type of response unless it indicates to the server that it is
102 capable of handling them; see the writeup of the ASYN command later in this
108 Zero or more parameters may be passed to a command. When more than one
109 parameter is passed to a command, they should be separated by the "|"
112 In this example, we're using the "SETU" command and passing three
113 parameters: 80, 24, and 260.
115 When the server spits out data that has parameters, if more than one
116 parameter is returned, they will be separated by the "|" symbol like
119 In this example, we just executed the "GETU" command, and it returned us
120 an OK result code (the '2' in the 200) and three parameters: 80, 24, and
127 This is a listing of all the commands that a Citadel server can execute.
132 This command does nothing. It takes no arguments and always returns
133 OK. It is intended primarily for testing and development, but it might also
134 be used as a "keep alive" command to prevent the server from timing out, if
135 it's running over a transport that needs this type of thing.
138 ECHO (ECHO something)
140 This command also does nothing. It simply returns OK followed by whatever
146 Terminate the server connection. This command takes no arguments. It
147 returns OK and closes the connection immediately.
152 Log out the user without closing the server connection. It always returns
153 OK even if no user is logged in.
156 USER (send USER name)
158 The first step in logging in a user. This command takes one argument: the
159 name of the user to be logged in. If the user exists, a MORE_DATA return
160 code will be sent, which means the client should execute PASS as the next
161 command. If the user does not exist, ERROR + NO_SUCH_USER is returned.
166 The second step in logging in a user. This command takes one argument: the
167 password for the user we are attempting to log in. If the password doesn't
168 match the correct password for the user we specified for the USER command,
169 ERROR + PASSWORD_REQUIRED is returned. If a USER command has not been
170 executed yet, ERROR + USERNAME_REQUIRED is returned. If a user is already
171 logged in, ERROR + ALREADY_LOGGED_IN is returned. If the password is
172 correct, OK is returned and the user is now logged in... and most of the
173 other server commands can now be executed. Along with OK, the following
174 parameters are returned:
176 0 - The user's name (in case the client wants the right upper/lower casing)
177 1 - The user's current access level
180 4 - Various flags (see citadel.h)
182 6 - Time of last call (UNIX timestamp)
185 NEWU (create NEW User account)
187 This command creates a new user account AND LOGS IT IN. The argument to
188 this command will be the name of the account. No case conversion is done
189 on the name. Note that the new account is installed with a default
190 configuration, and no password, so the client should immediately prompt the
191 user for a password and install it with the SETP command as soon as this
192 command completes. This command returns OK if the account was created and
193 logged in, ERROR + ALREADY_EXISTS if another user already exists with this
194 name, ERROR + NOT_HERE if self-service account creation is disabled,
195 ERROR + MAX_SESSIONS_EXCEEDED if too many users are logged in, ERROR +
196 USERNAME_REQUIRED if a username was not provided, or ERROR + ILELGAL_VALUE
197 if the username provided is invalid. If OK, it will also return the same
198 parameters that PASS returns.
200 Please note that the NEWU command should only be used for self-service
201 user account creation. For administratively creating user accounts, please
202 use the CREU command.
205 SETP (SET new Password)
207 This command sets a new password for the currently logged in user. The
208 argument to this command will be the new password. The command always
209 returns OK, unless the client is not logged in, in which case it will return
210 ERROR + NOT_LOGGED_IN, or if the user is an auto-login user, in which case
211 it will return ERROR + NOT_HERE.
214 CREU (CREate new User account)
216 This command creates a new user account AND DOES NOT LOG IT IN. The first
217 argument to this command will be the name of the account. No case conversion
218 is done on the name. Note that the new account is installed with a default
219 configuration, and no password. The second argument is optional, and will be
220 an initial password for the user. This command returns OK if the account was
221 created, ERROR + HIGHER_ACCESS_REQUIRED if the user is not an Aide, ERROR +
222 USERNAME_REQUIRED if no username was specified, or ERROR + ALREADY_EXISTS if
223 another user already exists with this name.
225 Please note that CREU is intended to be used for activities in which a
226 system administrator is creating user accounts. For self-service user
227 account creation, use the NEWU command.
230 LKRN (List Known Rooms with New messages)
232 List known rooms with new messages. If the client is not logged in, ERROR +
233 NOT_LOGGED_IN is returned. Otherwise, LISTING_FOLLOWS is returned, followed
234 by the room listing. Each line in the listing contains the full name of a
235 room, followed by the '|' symbol, and then a number that may contain the
238 #define QR_PERMANENT 1 /* Room does not purge */
239 #define QR_PRIVATE 4 /* Set for any type of private room */
240 #define QR_PASSWORDED 8 /* Set if there's a password too */
241 #define QR_GUESSNAME 16 /* Set if it's a guessname room */
242 #define QR_DIRECTORY 32 /* Directory room */
243 #define QR_UPLOAD 64 /* Allowed to upload */
244 #define QR_DOWNLOAD 128 /* Allowed to download */
245 #define QR_VISDIR 256 /* Visible directory */
246 #define QR_ANONONLY 512 /* Anonymous-Only room */
247 #define QR_ANON2 1024 /* Anonymous-Option room */
248 #define QR_NETWORK 2048 /* Shared network room */
249 #define QR_PREFONLY 4096 /* Preferred status needed to enter */
250 #define QR_READONLY 8192 /* Aide status required to post */
252 Then it returns another '|' symbol, followed by a second set of bits comprised
255 #define QR2_SYSTEM 1 /* System room; hide by default */
256 #define QR2_SELFLIST 2 /* Self-service mailing list mgmt */
258 Other bits may be defined in the future. The listing terminates, as with
259 all listings, with "000" on a line by itself.
261 Starting with version 4.01 and above, floors are supported. The first
262 argument to LKRN should be the number of the floor to list rooms from. Only
263 rooms from this floor will be listed. If no arguments are passed to LKRN, or
264 if the floor number requested is (-1), rooms on all floors will be listed.
266 The third field displayed on each line is the number of the floor the room
267 is on. The LFLR command should be used to associate floor numbers with
270 The fourth field displayed on each line is a "room listing order." Unless
271 there is a compelling reason not to, clients should sort any received room
272 listings by this value.
274 The fifth field is a special bit bucket containing fields which pertain to
275 room access controls:
277 #define UA_KNOWN 2 /* Known room */
278 #define UA_GOTOALLOWED 4 /* Access will be granted to this room
279 * if the user calls it up by name */
280 #define UA_HASNEWMSGS 8 /* Unread messages exist in room */
281 #define UA_ZAPPED 16 /* Zapped from known rooms list */
283 The sixth field is the user's current view for the room. (See VIEW command)
286 LKRO (List Known Rooms with Old [no new] messages)
288 This follows the same usage and format as LKRN.
291 LZRM (List Zapped RooMs)
293 This follows the same usage and format as LKRN and LKRO.
296 LKRA (List All Known Rooms)
298 Same format. Lists all known rooms, with or without new messages.
301 LRMS (List all accessible RooMS)
303 Again, same format. This command lists all accessible rooms, known and
304 forgotten, with and without new messages. It does not, however, list
305 inaccessible private rooms.
308 LPRM (List all Public RooMs)
310 Again, same format. This command lists all public rooms, and nothing else.
311 Unlike the other list rooms commands, this one can be executed without logging
315 GETU (GET User configuration)
317 This command retrieves the screen dimensions and user options for the
318 currently logged in account. ERROR + NOT_LOGGED_IN will be returned if no
319 user is logged in, of course. Otherwise, OK will be returned, followed by
320 four parameters. The first parameter is the user's screen width, the second
321 parameter is the user's screen height, and the third parameter is a bag of
322 bits with the following meanings:
324 #define US_LASTOLD 16 /* Print last old message with new */
325 #define US_EXPERT 32 /* Experienced user */
326 #define US_UNLISTED 64 /* Unlisted userlog entry */
327 #define US_NOPROMPT 128 /* Don't prompt after each message */
328 #define US_DISAPPEAR 512 /* Use "disappearing msg prompts" */
329 #define US_PAGINATOR 2048 /* Pause after each screen of text */
331 There are other bits, too, but they can't be changed by the user (see below).
334 SETU (SET User configuration)
336 This command does the opposite of SETU: it takes the screen dimensions and
337 user options (which were probably obtained with a GETU command, and perhaps
338 modified by the user) and writes them to the user account. This command
339 should be passed three parameters: the screen width, the screen height, and
340 the option bits (see above). It returns ERROR + NOT_LOGGED_IN if no user is
341 logged in, and ERROR + ILLEGAL_VALUE if the parameters are incorrect.
343 Note that there exist bits here which are not listed in this document. Some
344 are flags that can only be set by Aides or the system administrator. SETU
345 will ignore attempts to toggle these bits. There also may be more user
346 settable bits added at a later date. To maintain later downward compatibility,
347 the following procedure is suggested:
349 1. Execute GETU to read the current flags
350 2. Toggle the bits that we know we can toggle
351 3. Execute SETU to write the flags
353 If we are passed a bit whose meaning we don't know, it's best to leave it
354 alone, and pass it right back to the server. That way we can use an old
355 client on a server that uses an unknown bit without accidentally clearing
356 it every time we set the user's configuration.
361 This command is used to goto a new room. When the user first logs in (login
362 is completed after execution of the PASS command) this command is
363 automatically and silently executed to take the user to the first room in the
364 system (usually called the Lobby).
366 This command can be passed one or two parameters. The first parameter is,
367 of course, the name of the room. Although it is not case sensitive, the
368 full name of the room must be used. Wildcard matching or unique string
369 matching of room names should be the responsibility of the client.
371 Note that the reserved room name "_BASEROOM_" can be passed to the server
372 to cause the goto command to take the user to the first room in the system,
373 traditionally known as the Lobby>. As long as a user is logged in, a
374 GOTO command to _BASEROOM_ is guaranteed to succeed. This is useful to
375 allow client software to return to the base room when it doesn't know
378 There are also two additional reserved room names:
379 "_MAIL_" translates to the system's designated room for e-mail messages.
380 "_BITBUCKET_" goes to whatever room has been chosen for messages
383 The second (and optional) parameter is a password, if one is required for
384 access to the room. This allows for all types of rooms to be accessed via
385 this command: for public rooms, invitation-only rooms to which the user
386 has access, and preferred users only rooms to which the user has access, the
387 room will appear in a room listing. For guess-name rooms, this command
388 will work transparently, adding the room to the user's known room list when
389 it completes. For passworded rooms, access will be denied if the password
390 is not supplied or is incorrect, or the command will complete successfully
391 if the password is correct.
393 The third (and also) optional parameter is a "transient" flag. Normally,
394 when a user enters a private and/or zapped room, the room is added to the
395 user's known rooms list. If the transient flag is set to non-zero, this is
396 called a "transient goto" which causes the user to enter the room without
397 adding the room to the known rooms list.
399 The possible result codes are:
401 OK - The command completed successfully. User is now in the room.
402 (See the list of returned parameters below)
404 ERROR - The command did not complete successfully. Check the second and
405 third positions of the result code to find out what happened:
407 NOT_LOGGED_IN - Of course you can't go there. You didn't log in.
408 PASSWORD_REQUIRED - Either a password was not supplied, or the supplied
409 password was incorrect.
410 ROOM_NOT_FOUND - The requested room does not exist.
412 The typical procedure for entering a passworded room would be:
414 1. Execute a GOTO command without supplying any password.
415 2. ERROR + PASSWORD_REQUIRED will be returned. The client now knows that
416 the room is passworded, and prompts the user for a password.
417 3. Execute a GOTO command, supplying both the room name and the password.
418 4. If OK is returned, the command is complete. If, however,
419 ERROR + PASSWORD_REQUIRED is still returned, tell the user that the supplied
420 password was incorrect. The user remains in the room he/she was previously
423 When the command succeeds, these parameters are returned:
424 0. The name of the room
425 1. Number of unread messages in this room
426 2. Total number of messages in this room
427 3. Info flag: set to nonzero if the user needs to read this room's info
428 file (see RINF command below)
429 4. Various flags associated with this room. (See LKRN cmd above)
430 5. The highest message number present in this room
431 6. The highest message number the user has read in this room
432 7. Boolean flag: 1 if this is a Mail> room, 0 otherwise.
433 8. Aide flag: 1 if the user is either the Room Aide for this room, *or* is
434 a regular Aide (this makes access checks easy).
435 9. The number of new Mail messages the user has (useful for alerting the
436 user to the arrival of new mail during a session)
437 10. The floor number this room resides on
438 11. The *current* "view" for this room (see views.txt for more info)
439 12. The *default* "view" for this room
441 The default view gives the client a hint as to what views the user should
442 be allowed to select. For example, it would be confusing to allow messages
443 in a room intended for calendar items. The server does not enforce these
444 restrictions, though.
447 MSGS (get pointers to MeSsaGeS in this room)
449 This command obtains a listing of all the messages in the current room
450 which the client may request. This command may be passed a single parameter:
451 either "all", "old", or "new" to request all messages, only old messages, or
452 new messages. Or it may be passed two parameters: "last" plus a number, in
453 which case that many message pointers will be returned; "first" plus a
454 number, for the corresponding effect; or "gt" plus a number, to list all
455 messages in the current room with a message number greater than the one
456 specified. If no parameters are specified, "all" is assumed.
458 The third argument, may be either 0 or 1. If it is 1, this command behaves
459 differently: before a listing is returned, the client must transmit a list
460 of fields to search for. The field headers are listed below in the writeup
461 for the "MSG0" command.
463 The optional fourth argument may also be either 0 or 1. If it is 1, the
464 output of this command will include not only a list of message numbers, but
465 a simple header summary of each message as well. This is somewhat resource
466 intensive so you shouldn't do this unless you absolutely need all the headers
467 immediately. The fields which are output (in the usual delimited fashion, of
468 course) are: message number, timestamp, display name, node name, Internet
469 email address (if present), subject (if present).
471 This command can return three possible results. ERROR + NOT_LOGGED_IN will
472 be returned if no user is currently logged in. Otherwise, LISTING_FOLLOWS
473 will be returned, and the listing will consist of zero or more message
474 numbers, one per line. The listing ends, as always, with the string "000"
475 alone on a line by itself. The listed message numbers can be used to request
476 messages from the system. If "search mode" is being used, the server will
477 return START_CHAT_MODE, and the client is expected to transmit the search
478 criteria, and then read the message list.
480 Since this is somewhat complex, here are some examples:
482 Example 1: Read all new messages
485 Server: 100 Message list...
491 Example 2: Read the last five messages
494 Server: 100 Message list...
502 Example 3: Read all messages written by "IGnatius T Foobar"
505 Server: 800 Send template then receive message list
506 Client: from|IGnatius T Foobar
520 Note that in "search mode" the client may specify any number of search
521 criteria. These criteria are applied with an AND logic.
524 MSG0 (read MeSsaGe, mode 0)
526 This is a command used to read the text of a message. "Mode 0" implies that
527 other MSG commands (MSG1, MSG2, etc.) will probably be added later on to read
528 messages in more robust formats. This command should be passed two arguments.
529 The first is the message number of the message being requested. The second
530 argument specifies whether the client wants headers and/or message body:
534 3 = Headers only, with MIME information suppressed (this runs faster)
536 If the request is denied, ERROR + NOT_LOGGED_IN or ERROR + MESSAGE_NOT_FOUND
537 will be returned. Otherwise, LISTING_FOLLOWS will be returned, followed by
538 the contents of the message. The following fields may be sent:
540 type= Formatting type. The currently defined types are:
541 0 = "traditional" Citadel formatting. This means that newlines should be
542 treated as spaces UNLESS the first character on the next line is a space. In
543 other words, only indented lines should generate a newline on the user's screen
544 when the message is being displayed. This allows a message to be formatted to
545 the reader's screen width. It also allows the use of proportional fonts.
546 1 = a simple fixed-format message. The message should be displayed to
547 the user's screen as is, preferably in a fixed-width font that will fit 80
549 4 = MIME format message. The message text is expected to contain a header
550 with the "Content-type:" directive (and possibly others).
552 msgn= The message ID of this message on the system it originated on.
553 path= An e-mailable path back to the user who wrote the message.
555 time= The date and time of the message, in Unix format (the number of
556 seconds since midnight on January 1, 1970, GMT).
558 from= The name of the author of the message.
559 rcpt= If the message is a private e-mail, this is the recipient.
560 room= The name of the room the message originated in.
561 node= The short node name of the system this message originated on.
562 hnod= The long node name of the system this message originated on.
563 zaps= The id/node of a message which this one zaps (supersedes).
565 part= Information about a MIME part embedded in this message.
566 pref= Information about a multipart MIME prefix such as "multipart/mixed"
567 or "multipart/alternative". This will be output immediately prior
568 to the various "part=" lines which make up the multipart section.
569 suff= Information about a multipart MIME suffix. This will be output
570 immediately following the various "part=" lines which make up the
573 text Note that there is no "=" after the word "text". This string
574 signifies that the message text begins on the next line.
577 WHOK (WHO Knows room)
579 This command is available only to Aides. ERROR + HIGHER_ACCESS_REQUIRED
580 will be returned if the user is not an Aide. Otherwise, it returns
581 LISTING_FOLLOWS and then lists, one user per line, every user who has
582 access to the current room.
585 INFO (get server INFO)
587 This command will *always* return LISTING_FOLLOWS and then print out a
588 listing of zero or more strings. Client software should be written to expect
589 anywhere from a null listing to an infinite number of lines, to allow later
590 backward compatibility. The current implementation defines the following
591 parts of the listing:
593 Line 1 - Your unique session ID on the server
594 Line 2 - The node name of the Citadel server
595 Line 3 - Human-readable node name of the Citadel server
596 Line 4 - The fully-qualified domain name (FQDN) of the server
597 Line 5 - The name of the server software, i.e. "Citadel 4.00"
598 Line 6 - (The revision level of the server code) * 100
599 Line 7 - The geographical location of the site (city and state if in the US)
600 Line 8 - The name of the system administrator
601 Line 9 - A number identifying the server type (see below)
602 Line 10 - The text of the system's paginator prompt
603 Line 11 - Floor Flag. 1 if the system supports floors, 0 otherwise.
604 Line 12 - Paging level. 0 if the system only supports inline paging,
605 1 if the system supports "extended" paging (check-only and
606 multiline modes). See the SEXP command for further information.
607 Line 13 - The "nonce" for this session, for support of APOP-style
608 authentication. If this field is present, clients may authenticate
610 Line 14 - Set to nonzero if this server supports the QNOP command.
611 Line 15 - Set to nonzero if this server is capable of connecting to a
612 directory service using LDAP.
614 *** NOTE! *** The "server type" code is intended to promote global
615 compatibility in a scenario in which developers have added proprietary
616 features to their servers or clients. We are attempting to avoid a future
617 situation in which users need to keep different client software around for
618 each Citadel they use. *Please*, if you are a developer and plan to add
619 proprietary features:
621 -> Your client programs should still be able to utilize servers other than
623 -> Clients other than your own should still be able to utilize your server,
624 even if your proprietary extensions aren't supported.
625 -> Please contact Art Cancro <ajc@uncensored.citadel.org> and obtain a unique
626 server type code, which can be assigned to your server program.
627 -> If you document what you did in detail, perhaps it can be added to a
628 future release of the Citadel program, so everyone can enjoy it. Better
629 yet, just work with the Citadel development team on the main source tree.
631 If everyone follows this scheme, we can avoid a chaotic situation with lots
632 of confusion about which client program works with which server, etc. Client
633 software can simply check the server type (and perhaps the revision level)
634 to determine ahead of time what commands may be utilized.
636 Please refer to "developers.txt" for information on what codes belong to whom.
640 RDIR (Read room DIRectory)
642 Use this command to read the directory of a directory room. ERROR + NOT_HERE
643 will be returned if the room has no directory, ERROR + HIGHER_ACCESS_REQUIRED
644 will be returned if the room's directory is not visible and the user does not
645 have Aide or Room Aide privileges, ERROR + NOT_LOGGED_IN will be returned if
646 the user is not logged in; otherwise LISTING_FOLLOWS will be returned,
647 followed by the room's directory. Each line of the directory listing will
648 contain three fields: a filename, the length of the file, and a description.
650 The server message contained on the same line with LISTING_FOLLOWS will
651 contain the name of the system and the name of the directory, such as:
653 uncensored.citadel.org|/usr/local/citadel/files/my_room_directory
656 SLRP (Set Last-message-Read Pointer)
658 This command marks all messages in the current room as read (seen) up to and
659 including the specified number. Its sole parameter is the number of the last
660 message that has been read. This allows the pointer to be set at any
661 arbitrary point in the room. Optionally, the parameter "highest" may be used
662 instead of a message number, to set the pointer to the number of the highest
663 message in the room, effectively marking all messages in the room as having
664 been read (ala the Citadel <G>oto command).
666 The command will return OK if the pointer was set, or ERROR + NOT_LOGGED_IN
667 if the user is not logged in. If OK is returned, it will be followed by a
668 single argument containing the message number the last-read-pointer was set to.
671 INVT (INViTe a user to a room)
673 This command may only be executed by Aides, or by the room aide for the
674 current room. It is used primarily to add users to invitation-only rooms,
675 but it may also be used in other types of private rooms as well. Its sole
676 parameter is the name of the user to invite.
678 The command will return OK if the operation succeeded. ERROR + NO_SUCH_USER
679 will be returned if the user does not exist, ERROR + HIGHER_ACCESS_REQUIRED
680 will be returned if the operation would have been possible if the user had
681 higher access, and ERROR + NOT_HERE may be returned if the room is not a
685 KICK (KICK a user out of a room)
687 This is the opposite of INVT: it is used to kick a user out of a private
688 room. It can also be used to kick a user out of a public room, but the
689 effect will only be the same as if the user <Z>apped the room - a non-stupid
690 user can simply un-zap the room to get back in.
693 GETR (GET Room attributes)
695 This command is used for editing the various attributes associated with a
696 room. A typical "edit room" command would work like this:
697 1. Use the GETR command to get the current attributes
698 2. Change some of them around
699 3. Use SETR (see below) to save the changes
700 4. Possibly also change the room aide using the GETA and SETA commands
702 GETR takes no arguments. It will only return OK if the SETR command will
703 also return OK. This allows client software to tell the user that he/she
704 can't edit the room *before* going through the trouble of actually doing the
705 editing. Possible return codes are:
707 ERROR+NOT_LOGGED_IN - No user is logged in.
708 ERROR+HIGHER_ACCESS_REQUIRED - Not enough access. Typically, only aides
709 and the room aide associated with the current room, can access this command.
710 OK - Command succeeded. Parameters are returned.
712 If OK is returned, the following parameters will be returned as well:
714 0. The name of the room
715 1. The room's password (if it's a passworded room)
716 2. The name of the room's directory (if it's a directory room)
717 3. Various flags (bits) associated with the room (see LKRN cmd above)
718 4. The floor number on which the room resides
719 5. The room listing order
720 6. The default view for the room (see views.txt)
721 7. A second set of flags (bits) associated with the room
724 SETR (SET Room attributes)
726 This command sets various attributes associated with the current room. It
727 should be passed the following arguments:
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. "Bump" flag (see below)
734 5. The floor number on which the room should reside
735 6. The room listing order
736 7. The default view for the room (see views.txt)
737 8. A second set of flags (bits) associated with the room
739 *Important: You should always use GETR to retrieve the current attributes of
740 the room, then change what you want to change, and then use SETR to write it
741 all back. This is particularly important with respect to the flags: if a
742 particular bit is set, and you don't know what it means, LEAVE IT ALONE and
743 only toggle the bits you want to toggle. This will allow for upward
746 The _BASEROOM_, user's Mail> and Aide> rooms can only be partially edited.
747 Any changes which cannot be made will be silently ignored.
749 If the room is a private room, you have the option of causing all users who
750 currently have access, to forget the room. If you want to do this, set the
751 "bump" flag to 1, otherwise set it to 0.
756 This command is used to get the name of the Room Aide for the current room.
757 It will return ERROR + NOT_LOGGED_IN if no user is logged in, or OK if the
758 command succeeded. Along with OK there will be returned one parameter: the
759 name of the Room Aide. A conforming server must guarantee that the user is
765 The opposite of GETA, used to set the Room Aide for the current room. One
766 parameter should be passed, which is the name of the user who is to be the
767 new Room Aide. Under Citadel, this command may only be executed by Aides
768 and by the *current* Room Aide for the room. Return codes possible are:
769 ERROR + NOT_LOGGED_IN (Not logged in.)
770 ERROR + HIGHER_ACCESS_REQUIRED (Higher access required.)
771 ERROR + NOT_HERE (Room cannot be edited.)
772 OK (Command succeeded.)
775 ENT0 (ENTer message, mode 0)
777 This command is used to enter messages into the system. It accepts four
780 0 - Post flag. This should be set to 1 to post a message. If it is
781 set to 0, the server only returns OK or ERROR (plus any flags describing
782 the error) without reading in a message. Client software should, in fact,
783 perform this operation at the beginning of an "enter message" command
784 *before* starting up its editor, so the user does not end up typing a message
785 in vain that will not be permitted to be saved. If it is set to 2, the
786 server will accept an "apparent" post name if the user is privileged enough.
787 This post name is arg 5.
788 1 - Recipient. This argument is utilized only for private mail messages.
789 It is ignored for public messages. It contains, of course, the name of the
790 recipient of the message.
791 2 - Anonymous flag. This argument is ignored unless the room allows
792 anonymous messages. In such rooms, this flag may be set to 1 to flag a
793 message as anonymous, otherwise 0 for a normal message.
794 3 - Format type. Any valid Citadel format type may be used (this will
795 typically be 0; see the MSG0 command above).
796 4 - Subject. If present, this argument will be used as the subject of
798 5 - Post name. When postflag is 2, this is the name you are posting as.
799 This is an Aide only command.
800 6 - Do Confirmation. NOTE: this changes the protocol semantics! When
801 you set this to nonzero, ENT0 will reply with a confirmation message after
802 you submit the message text. The reply code for the ENT0 command will be
803 START_CHAT_MODE instead of SEND_LISTING.
805 Possible result codes:
806 OK - The request is valid. (Client did not set the "post" flag, so the
807 server will not read in message text.) If the message is an e-mail with
808 a recipient, the text that follows the OK code will contain the exact name
809 to which mail is being sent. The client can display this to the user. The
810 implication here is that the name that the server returns will contain the
811 correct upper and lower case characters. In addition, if the recipient is
812 having his/her mail forwarded, the forwarding address will be returned.
813 SEND_LISTING - The request is valid. The client should now transmit
814 the text of the message (ending with a 000 on a line by itself, as usual).
815 START_CHAT_MODE - The request is valid. The client should now transmit
816 the text of the message, ending with a 000 on a line by itself. After
817 transmitting the 000 terminator, the client MUST read in the confirmation
818 from the server, which will also end with 000 on a line by itself. The format
819 of the confirmation appears below.
820 ERROR + NOT_LOGGED_IN - Not logged in.
821 ERROR + HIGHER_ACCESS_REQUIRED - Higher access is required. An
822 explanation follows, worded in a form that can be displayed to the user.
823 ERROR + NO_SUCH_USER - The specified recipient does not exist.
825 The format of the confirmation message, if requested, is as follows:
826 Line 1: The new message number on the server for the message. It will be
827 positive for a real message number, or negative to denote
828 that an error occurred. If an error occurred, the message was
830 Line 2: A human-readable confirmation or error message.
831 Line 3: The resulting Exclusive UID of the message, if present.
832 (More may be added to this in the future, so do not assume that there will
833 only be these lines output. Keep reading until 000 is received.)
836 RINF (read Room INFormation file)
838 Each room has associated with it a text file containing a description of
839 the room, perhaps containing its intended purpose or other important
840 information. The info file for the Lobby> (the system's base room) is
841 often used as a repository for system bulletins and the like.
843 This command, which accepts no arguments, is simply used to read the info
844 file for the current room. It will return LISTING_FOLLOWS followed by
845 the text of the message (always in format type 0) if the request can be
846 honored, or ERROR if no info file exists for the current room (which is
847 often the case). Other error description codes may accompany this result.
849 When should this command be used? This is, of course, up to the discretion
850 of client software authors, but in Citadel it is executed in two situations:
851 the first time the user ever enters a room; and whenever the contents of the
852 file change. The latter can be determined from the result of a GOTO command,
853 which will tell the client whether the file needs to be read (see GOTO above).
856 DELE (DELEte a message)
858 Delete a message from the current room. The one argument that should be
859 passed to this command is the message number of the message to be deleted.
860 The return value will be OK if the message was deleted, or an ERROR code.
861 If the delete is successful, the message's reference count is decremented, and
862 if the reference count reaches zero, the message is removed from the message
866 MOVE (MOVE or copy a message to a different room)
868 Move or copy a message to a different room. This command expects to be
869 passed three arguments:
870 0: the message number of the message to be moved or copied.
871 1: the name of the target room.
872 2: flag: 0 to move the message, 1 to copy it without deleting from the
875 This command never creates or deletes copies of a message; it merely moves
876 around links. When a message is moved, its reference count remains the same.
877 When a message is copied, its reference count is incremented.
880 KILL (KILL current room)
882 This command deletes the current room. It accepts a single argument, which
883 should be nonzero to actually delete the room, or zero to merely check
884 whether the room can be deleted.
886 Once the room is deleted, the current room is undefined. It is suggested
887 that client software immediately GOTO another room (usually _BASEROOM_)
888 after this command completes.
890 Possible return codes:
892 OK - room has been deleted (or, if checking only, request is valid).
893 ERROR+NOT_LOGGED_IN - no user is logged in.
894 ERROR+HIGHER_ACCESS_REQUIRED - not enough access to delete rooms.
895 ERROR+NOT_HERE - this room can not be deleted.
898 CRE8 (CRE[ate] a new room)
900 This command is used to create a new room. Like some of the other
901 commands, it provides a mechanism to first check to see if a room can be
902 created before actually executing the command. CRE8 accepts the following
905 0 - Create flag. Set this to 1 to actually create the room. If it is
906 set to 0, the server merely checks that there is a free slot in which to
907 create a new room, and that the user has enough access to create a room. It
908 returns OK if the client should go ahead and prompt the user for more info,
909 or ERROR or ERROR+HIGHER_ACCESS_REQUIRED if the command will not succeed.
910 1 - Name for new room.
911 2 - Access type for new room:
913 1 - Private; can be entered by guessing the room's name
914 2 - Private; can be entered by knowing the name *and* password
915 3 - Private; invitation only (sometimes called "exclusive")
916 4 - Personal (mailbox for this user only)
917 3 - Password for new room (if it is a type 2 room)
918 4 - Floor number on which the room should reside (optional)
919 5 - Set to 1 to avoid automatically gaining access to the created room.
920 6 - The default "view" for the room.
922 If the create flag is set to 1, the room is created (unless something
923 went wrong and an ERROR return is sent), and the server returns OK, but
924 the session is **not** automatically sent to that room. The client still
925 must perform a GOTO command to go to the new room.
928 FORG (FORGet the current room)
930 This command is used to forget (zap) the current room. For those not
931 familiar with Citadel, this terminology refers to removing the room from
932 a user's own known rooms list, *not* removing the room itself. After a
933 room is forgotten, it no longer shows up in the user's known room list,
934 but it will exist in the user's forgotten room list, and will return to the
935 known room list if the user goes to the room (in Citadel, this is
936 accomplished by explicitly typing the room's name in a <.G>oto command).
938 The command takes no arguments. If the command cannot execute for any
939 reason, ERROR will be returned. ERROR+NOT_LOGGED_IN or ERROR+NOT_HERE may
940 be returned as they apply.
942 If the command succeeds, OK will be returned. At this point, the current
943 room is **undefined**, and the client software is responsible for taking
944 the user to another room before executing any other room commands (usually
945 this will be _BASEROOM_ since it is always there).
948 MESG (read system MESsaGe)
950 This command is used to display system messages and/or help files. The
951 single argument it accepts is the name of the file to display. IT IS CASE
952 SENSITIVE. Citadel looks for these files first in the "messages"
953 subdirectory and then in the "help" subdirectory.
955 If the file is found, LISTING_FOLLOWS is returned, followed by a pathname
956 to the file being displayed. Then the message is printed, in format type 0
957 (see MSG0 command for more information on this). If the file is not found,
960 There are some "well known" names of system messages which client software
961 may expect most servers to carry:
963 hello - Welcome message, to be displayed before the user logs in.
964 changepw - To be displayed whenever the user is prompted for a new
965 password. Warns about picking guessable passwords and such.
966 register - Should be displayed prior to the user entering registration.
967 Warnings about not getting access if not registered, etc.
968 help - Main system help file.
969 goodbye - System logoff banner; display when user logs off.
970 roomaccess - Information about how public rooms and different types of
971 private rooms function with regards to access.
972 unlisted - Tells users not to choose to be unlisted unless they're
973 really paranoid, and warns that aides can still see
974 unlisted userlog entries.
976 Citadel provides these for the Citadel Unix text client. They are
977 probably not very useful for other clients:
979 mainmenu - Main menu (when in idiot mode).
984 saveopt - Options to save a message, abort, etc.
985 entermsg - Displayed just before a message is entered, when in
989 GNUR (Get Next Unvalidated User)
991 This command shows the name of a user that needs to be validated. If there
992 are no unvalidated users, OK is returned. Otherwise, MORE_DATA is returned
993 along with the name of the first unvalidated user the server finds. All of
994 the usual ERROR codes may be returned as well (for example, if the user is
995 not an Aide and cannot validate users).
997 A typical "Validate New Users" command would keep executing this command,
998 and then validating each user it returns, until it returns OK when all new
999 users have been validated.
1002 GREG (Get REGistration for user)
1004 This command retrieves the registration info for a user, whose name is the
1005 command's sole argument. All the usual error messages can be returned. If
1006 the command succeeds, LISTING_FOLLOWS is returned, followed by the user's name
1007 (retrieved from the userlog, with the right upper and lower case etc.) The
1008 contents of the listing contains one field per line, followed by the usual
1009 000 on the last line.
1011 The following lines are defined. Others WILL be added in the futre, so all
1012 software should be written to read the lines it knows about and then ignore
1013 all remaining lines:
1018 Line 4: Street address or PO Box
1019 Line 5: City/town/village/etc.
1020 Line 6: State/province/etc.
1022 Line 8: Telephone number
1023 Line 9: Access level
1024 Line 10: Internet e-mail address
1027 Users without Aide privileges may retrieve their own registration using
1028 this command. This can be accomplished either by passing the user's own
1029 name as the argument, or the string "_SELF_". The command will always
1030 succeed when used in this manner, unless no user is logged in.
1033 VALI (VALIdate user)
1035 This command is used to validate users. Obviously, it can only be executed
1036 by users with Aide level access. It should be passed two parameters: the
1037 name of the user to validate, and the desired access level
1039 If the command succeeds, OK is returned. The user's access level is changed
1040 and the "need validation" bit is cleared. If the command fails for any
1041 reason, ERROR, ERROR+NO_SUCH_USER, or ERROR+HIGHER_ACCESS_REQUIRED will be
1045 EINF (Enter INFo file for room)
1047 Transmit the info file for the current room with this command. EINF uses
1048 a boolean flag (1 or 0 as the first and only argument to the command) to
1049 determine whether the client actually wishes to transmit a new info file, or
1050 is merely checking to see if it has permission to do so.
1052 If the command cannot succeed, it returns ERROR.
1053 If the client is only checking for permission, and permission will be
1054 granted, OK is returned.
1055 If the client wishes to transmit the new info file, SEND_LISTING is
1056 returned, and the client should transmit the text of the info file, ended
1057 by the usual 000 on a line by itself.
1062 This is a simple user listing. It always succeeds, returning
1063 LISTING_FOLLOWS followed by zero or more user records, 000 terminated. The
1064 fields on each line are as follows:
1069 4. Date/time of last login (Unix format)
1072 7. Password (listed only if the user requesting the list is an Aide)
1074 Unlisted entries will also be listed to Aides logged into the server, but
1075 not to ordinary users.
1077 The LIST command accepts an optional single argument, which is a simple,
1078 case-insensitive search string. If this argument is present, only usernames
1079 in which the search string is present will be returned. It is a simple
1080 substring search, not a regular expression search. If this string is empty
1081 or not present, all users will be returned.
1084 REGI (send REGIstration)
1086 Clients will use this command to transmit a user's registration info. If
1087 no user is logged in, ERROR+NOT_LOGGED_IN is returned. Otherwise,
1088 SEND_LISTING is returned, and the server will expect the following information
1089 (terminated by 000 on a line by itself):
1092 Line 2: Street address or PO Box
1093 Line 3: City/town/village/etc.
1094 Line 4: State/province/etc.
1096 Line 6: Telephone number
1097 Line 7: e-mail address
1101 CHEK (CHEcK various things)
1103 When logging in, there are various things that need to be checked. This
1104 command will return ERROR+NOT_LOGGED_IN if no user is logged in. Otherwise
1105 it returns OK and the following parameters:
1107 0: Number of new private messages in Mail>
1108 1: Nonzero if the user needs to register
1109 2: (Relevant to Aides only) Nonzero if new users require validation
1110 3: The user's preferred Internet e-mail address
1113 DELF (DELete a File)
1115 This command deletes a file from the room's directory, if there is one. The
1116 name of the file to delete is the only parameter to be supplied. Wildcards
1117 are not acceptable, and any slashes in the filename will be converted to
1118 underscores, to prevent unauthorized access to neighboring directories. The
1119 possible return codes are:
1121 OK - Command succeeded. The file was deleted.
1122 ERROR+NOT_LOGGED_IN - Not logged in.
1123 ERROR+HIGHER_ACCESS_REQUIRED - Not an Aide or Room Aide.
1124 ERROR+NOT_HERE - There is no directory in this room.
1125 ERROR+FILE_NOT_FOUND - Requested file was not found.
1130 This command is similar to DELF, except that it moves a file (and its
1131 associated file description) to another room. It should be passed two
1132 parameters: the name of the file to move, and the name of the room to move
1133 the file to. All of the same return codes as DELF may be returned, and also
1134 one additional one: ERROR+NO_SUCH_ROOM, which means that the target room
1135 does not exist. ERROR+NOT_HERE could also mean that the target room does
1136 not have a directory.
1139 NETF (NETwork send a File)
1141 This command is similar to MOVF, except that it attempts to send a file over
1142 the network to another system. It should be passed two parameters: the name
1143 of the file to send, and the node name of the system to send it to. All of
1144 the same return codes as MOVF may be returned, except for ERROR+NO_SUCH_ROOM.
1145 Instead, ERROR+NO_SUCH_SYSTEM may be returned if the name of the target
1148 The name of the originating room will be sent along with the file. Most
1149 implementations will look for a room with the same name at the receiving end
1150 and attempt to place the file there, otherwise it goes into a bit bucket room
1151 for miscellaneous files. This is, however, beyond the scope of this document;
1152 see elsewhere for more details.
1155 RWHO (Read WHO's online)
1157 Displays a list of all users connected to the server. No error codes are
1158 ever returned. LISTING_FOLLOWS will be returned, followed by zero or more
1159 lines containing the following three fields:
1161 0 - Session ID. Citadel fills this with the pid of a server program.
1163 2 - The name of the room the user is currently in. This field might not
1164 be displayed (for example, if the user is in a private room) or it might
1165 contain other information (such as the name of a file the user is
1167 3 - (server v4.03 and above) The name of the host the client is connecting
1168 from, or "localhost" if the client is local.
1169 4 - (server v4.04 and above) Description of the client software being used
1170 5 - The last time, locally to the server, that a command was received from
1171 this client (Note: NOOP's don't count)
1172 6 - The last command received from a client. (NOOP's don't count)
1173 7 - Session flags. These are: + (spoofed address), - (STEALTH mode), *
1174 (posting) and . (idle).
1175 8 - Actual user name, if user name is masqueraded and viewer is an Aide.
1176 9 - Actual room name, if room name is masqueraded and viewer is an Aide.
1177 10 - Actual host name, if host name is masqueraded and viewer is an Aide.
1178 11 - Nonzero if the session is a logged-in user, zero otherwise.
1180 The listing is terminated, as always, with the string "000" on a line by
1184 OPEN (OPEN a file for download)
1186 This command is used to open a file for downloading. Only one download
1187 file may be open at a time. The only argument to this command is the name
1188 of the file to be opened. The user should already be in the room where the
1189 file resides. Possible return codes are:
1192 ERROR+NOT_HERE (no directory in this room)
1193 ERROR+FILE_NOT_FOUND (could not open the file)
1197 If the file is successfully opened, OK will be returned, along with the
1198 size (in bytes) of the file, the time of last modification (if applicable),
1199 the filename (if known), and the MIME type of the file (if known).
1202 CLOS (CLOSe the download file)
1204 This command is used to close the download file. It returns OK if the
1205 file was successfully closed, or ERROR if there wasn't any file open in the
1209 READ (READ from the download file)
1211 Two arguments are passed to this command. The first is the starting position
1212 in the download file, and the second is the total number of bytes to be
1213 read. If the operation can be performed, BINARY_FOLLOWS will be returned,
1214 along with the number of bytes to follow. Then, immediately following the
1215 newline, will be that many bytes of binary data. The client *must* read
1216 exactly that number of bytes, otherwise the client and server will get out
1219 If the operation cannot be performed, any of the usual error codes will be
1223 UOPN (OPeN a file for Uploading)
1225 This command is similar to OPEN, except that this one is used when the
1226 client wishes to upload a file to the server. The first argument is the name
1227 of the file to create, and the second argument is a one-line comment
1228 describing the contents of the file. Only one upload file may be open at a
1229 time. Possible return codes are:
1232 ERROR+NOT_HERE (no directory in this room)
1233 ERROR+FILE_NOT_FOUND (a name must be specified)
1234 ERROR (miscellaneous errors)
1235 ERROR+ALREADY_EXISTS (a file with the same name already exists)
1238 If OK is returned, the command has succeeded and writes may be performed.
1241 UCLS (CLoSe the Upload file)
1243 Close the file opened with UOPN. An argument of "1" should be passed to
1244 this command to close and save the file; otherwise, the transfer will be
1245 considered aborted and the file will be deleted. This command returns OK
1246 if the operation succeeded or ERROR if it did not.
1249 WRIT (WRITe to the upload file)
1251 If an upload file is open, this command may be used to write to it. The
1252 argument passed to this command is the number of bytes the client wishes to
1253 transmit. An ERROR code will be returned if the operation cannot be
1256 If the operation can be performed, SEND_BINARY will be returned, followed
1257 by the number of bytes the server is expecting. The client must then transmit
1258 exactly that number of bytes. Note that in the current implementation, the
1259 number of bytes the server is expecting will always be the number of bytes
1260 the client requested to transmit, but the client software should never assume
1261 that this will always happen, in case changes are made later.
1264 QUSR (Query for a USeR)
1266 This command is used to check to see if a particular user exists. The only
1267 argument to this command is the name of the user being searched for. If
1268 the user exists, OK is returned, along with the name of the user in the userlog
1269 (so the client software can learn the correct upper/lower casing of the name
1270 if necessary). If the user does not exist, ERROR+NO_SUCH_USER is returned.
1271 No login or current room is required to utilize this command.
1274 OIMG (Open an IMaGe file)
1276 Open an image (graphics) file for downloading. Once opened, the file can be
1277 read as if it were a download file. This implies that an image and a download
1278 cannot be opened at the same time. OIMG returns the same result codes as OPEN.
1280 All images will be in GIF (Graphics Interchange Format). In the case of
1281 Citadel, the server will convert the supplied filename to all lower case,
1282 append the characters ".gif" to the filename, and look for it in the "images"
1283 subdirectory. As with the MESG command, there are several "well known"
1284 images which are likely to exist on most servers:
1286 hello - "Welcome" graphics to be displayed alongside MESG "hello"
1287 goodbye - Logoff banner graphics to be displayed alongside MESG "goodbye"
1288 background - Background image (usually tiled) for graphical clients
1290 The following "special" image names are defined in Citadel server version
1293 _userpic_ - Picture of a user (send the username as the second argument)
1294 _floorpic_ - A graphical floor label (send the floor number as the second
1295 argument). Clients which request a floor picture will display
1296 the picture *instead* of the floor name.
1297 _roompic_ - A graphic associated with the *current* room. Clients which
1298 request a room picture will display the picture in *addition*
1299 to the room name (i.e. it's used for a room banner, as
1300 opposed to the floor picture's use in a floor listing).
1303 NETP (authenticate as network session with connection NET Password)
1305 This command is used by client software to identify itself as a transport
1306 session for Citadel site-to-site networking. It should be called with
1307 two arguments: the node name of the calling system, and the "shared secret"
1308 password for that connection. If the authentication succeeds, NETP will
1309 return OK, otherwise, it returns ERROR.
1312 NSYN (Network SYNchronize room)
1314 This command can be used to synchronize the contents of a room on the
1315 network. It is only usable by Aides. It accepts one argument: the name of
1316 a network node (which must be a valid one).
1318 When NSYN is run, the *entire* contents of the current room will be spooled
1319 to the specified node, without regard to whether any of the messages have
1320 already undergone network processing. It is up to the receiving node to
1321 check for duplicates (the Citadel networker does handle this) and avoid
1324 The command returns OK upon success or ERROR if the user is not an Aide.
1327 NUOP (Network Upload OPen file)
1329 Open a network spool file for uploading. The client must have already
1330 identified itself as a network session using the NETP command. If the command
1331 returns OK, the client may begin transmitting IGnet/Open spool data using
1332 a series of WRIT commands. When a UCLS command is issued, the spooled data
1333 is entered into the server if the argument to UCLS is 1 or discarded if the
1334 argument to UCLS is 0. If the client has not authenticated itself with a
1335 NETP command, ERROR+HIGHER_ACCESS_REQUIRED will be returned.
1338 NDOP (Network Download OPen file)
1340 Open a network spool file for downloading. The client must have already
1341 identified itself as a network session using the NETP command. If the command
1342 returns OK, the client may begin receiving IGnet/Open spool data using
1343 a series of READ commands. When a CLOS command is issued, the spooled data
1344 is deleted from the server and may not be read again. If the client has not
1345 authenticated itself with a NETP command, ERROR+HIGHER_ACCESS_REQUIRED will
1349 LFLR (List all known FLooRs)
1351 On systems supporting floors, this command lists all known floors. The
1352 command accepts no parameters. It will return ERROR+NOT_LOGGED_IN if no
1353 user is logged in. Otherwise it returns LISTING_FOLLOWS and a list of
1354 the available floors, each line consisting of three fields:
1356 1. The floor number associated with the floor
1357 2. The name of the floor
1358 3. Reference count (number of rooms on this floor)
1361 CFLR (Create a new FLooR)
1363 This command is used to create a new floor. It should be passed two
1364 arguments: the name of the new floor to be created, and a 1 or 0 depending
1365 on whether the client is actually creating a floor or merely checking to
1366 see if it has permission to create the floor. The user must be logged in
1367 and have Aide privileges to create a floor.
1369 If the command succeeds, it will return OK followed by the floor number
1370 associated with the new floor. Otherwise, it will return ERROR (plus perhaps
1371 HIGHER_ACCESS_REQUIRED, ALREADY_EXISTS, or INVALID_FLOOR_OPERATION)
1372 followed by a description of why the command failed.
1377 This command is used to delete a floor. It should be passed two
1378 argument: the *number* of the floor to be deleted, and a 1 or 0 depending
1379 on whether the client is actually deleting the floor or merely checking to
1380 see if it has permission to delete the floor. The user must be logged in
1381 and have Aide privileges to delete a floor.
1383 Floors that contain rooms may not be deleted. If there are rooms on a floor,
1384 they must be either deleted or moved to different floors first. This implies
1385 that the Main Floor (floor 0) can never be deleted, since Lobby>, Mail>, and
1386 Aide> all reside on the Main Floor and cannot be deleted.
1388 If the command succeeds, it will return OK. Otherwise it will return
1389 ERROR (plus perhaps HIGHER_ACCESS_REQUIRED or INVALID_FLOOR_OPERATION)
1390 followed by a description of why the command failed.
1395 Edit the parameters of a floor. The client may pass one or more parameters
1398 1. The number of the floor to be edited
1399 2. The desired new name
1401 More parameters may be added in the future. Any parameters not passed to
1402 the server will remain unchanged. A minimal command would be EFLR and a
1403 floor number -- which would do nothing. EFLR plus the floor number plus a
1404 floor name would change the floor's name.
1406 If the command succeeds, it will return OK. Otherwise it will return
1407 ERROR (plus perhaps HIGHER_ACCESS_REQUIRED or INVALID_FLOOR_OPERATION)
1410 IDEN (IDENtify the client software)
1412 The client software has the option to identify itself to the server.
1413 Currently, the server does nothing with this information except to write
1414 it to the syslog to satisfy the system administrator's curiosity. Other
1415 uses might become apparent in the future.
1417 The IDEN command should contain five fields: a developer ID number (same as
1418 the server developer ID numbers in the INFO command -- please obtain one if
1419 you are a new developer), a client ID number (which does not have to be
1420 globally unique - only unique within the domain of the developer number),
1421 a version number, a free-form text string describing the client, and the name
1422 of the host the user is located at.
1424 It is up to the server to determine whether to accept the host name or to
1425 use the host name it has detected itself. Generally, if the client is
1426 running on a trusted host (either localhost or a well-known publically
1427 accessible client) it should use the host name transmitted by IDEN,
1428 otherwise it should use the host name it has detected itself.
1430 IDEN always returns OK, but since that's the only way it ever returns
1431 there's no point in checking the result code.
1434 IPGM (identify as an Internal ProGraM)
1436 IPGM is a low-level command that should not be used by normal user clients.
1437 It is used for various utilities to communicate with the server on the same
1438 host. For example, the "sendcommand" utility logs onto the server as an
1439 internal program in order to run arbitrary server commands. Since user clients
1440 do not utilize this command (or any of its companion commands), developers
1441 writing Citadel-compatible servers need not implement it.
1443 The sole argument to IPGM is the system's internal program password. This
1444 password is generated by the setup program and stored in the config file.
1445 Since internal programs have access to the config file, they know the correct
1448 IPGM returns OK for a correct authentication or ERROR otherwise.
1451 CHAT (enter CHAT mode)
1453 This command functions differently from every other command in the system. It
1454 is used to implement multi-user chat. For this to function, a new transfer
1455 mode, called START_CHAT_MODE, is implemented. If a client does not support
1456 chat mode, it should never send a CHAT command!
1458 In chat mode, messages may arrive asynchronously from the server at any
1459 time. The client may send messages at any time. This allows the arrival of
1460 messages without the client having to poll for them. Arriving messages will
1461 be of the form "user|message", where the "user" portion is, of course, the
1462 name of the user sending the message, and "message" is the message text.
1464 Chat mode ends when the server says it ends. The server will signal the end
1465 of chat mode by transmitting "000" on a line by itself. When the client reads
1466 this line, it must immediately exit from chat mode without sending any
1467 further traffic to the server. The next transmission sent to the server
1468 will be a regular server command.
1470 The Citadel server understands the following commands:
1471 /quit - Exit from chat mode (causes the server to do an 000 end)
1472 /who - List users currently in chat
1473 /whobbs - List users currently in chat and elsewhere
1474 /me - Do an irc-style action.
1475 /join - Join a new "room" in which all messages are only heard by
1476 people in that room.
1477 /msg - /msg <user> <msg> will send the msg to <user> only.
1478 /help - Print help information
1479 NOOP - Do nothing (silently)
1481 Any other non-empty string is treated as message text and will be broadcast
1482 to other users currently in chat.
1485 SEXP (Send instant message)
1487 This is one of two commands which implement instant messages (also known
1488 as "paging"). Commands ending in "...EXP" are so-named because we called
1489 them "express messages" before the industry standardized on the term
1490 "instant messages." When an instant message is sent, it will be
1491 logged in user to another. When an instant message is sent, it will be
1492 displayed the next time the target user executes a PEXP or GEXP command.
1494 The SEXP command accepts two arguments: the name of the user to send the
1495 message to, and the text of the message. If the message is successfully
1496 transmitted, OK is returned. If the target user is not logged in or if
1497 anything else goes wrong, ERROR is returned.
1499 If the server supports extended paging, sending a zero-length message
1500 merely checks for the presence of the requested user without actually sending
1501 a message. Sending a message consisting solely of a "-" (hyphen) will cause
1502 the server to return SEND_LISTING if the requested user is logged in, and the
1503 client can then transmit a multi-line page.
1505 The reserved name "broadcast" may be used instead of a user name, to
1506 broadcast an instant message to all users currently connected to the server.
1508 Do be aware that if an instant message is transmitted to a user who is logged
1509 in using a client that does not check for instant messages, the message will
1510 never be received. Also, instant messages are NOT sent via the following
1511 transports: SMTP, POP3.
1514 PEXP (Print instant messages) ***DEPRECATED***
1516 This command is deprecated; it will eventually disappear from the protocol and
1517 its use is not recommended. Please use the GEXP command instead.
1519 Called without any arguments, PEXP simply dumps out the contents
1520 of any waiting instant messages. It returns ERROR if there is a problem,
1521 otherwise it returns LISTING_FOLLOWS followed by all messages.
1523 So how does the client know there are instant messages waiting? It could
1524 execute a random PEXP every now and then. Or, it can check the byte in
1525 server return code messages, between the return code and the parameters. In
1526 much the same way as FTP uses "-" to signify a continuation, Citadel uses
1527 an "*" in this position to signify the presence of waiting instant messages.
1530 EBIO (Enter BIOgraphy)
1532 Transmit to the server a free-form text file containing a little bit of
1533 information about the user for other users to browse. This is typically
1534 referred to as a 'bio' online. EBIO returns SEND_LISTING if it succeeds,
1535 after which the client is expected to transmit the file, or any of the usual
1536 ERROR codes if it fails.
1539 RBIO (Read BIOgraphy)
1541 Receive from the server a named user's bio. This command should be passed
1542 a single argument - the name of the user whose bio is requested. RBIO returns
1543 LISTING_FOLLOWS plus the bio file if the user exists and has a bio on file.
1544 The return has the following parameters: the user name, user number, access
1545 level, date of last call, times called, and messages posted. This command
1546 returns ERROR+NO_SUCH_USER if the named user does not exist.
1548 RBIO no longer considers a user with no bio on file to be an error condition.
1549 It now returns a message saying the user has no bio on file as the text of the
1550 bio. This allows newer servers to operate with older clients.
1553 STEL (enter STEaLth mode)
1555 When in "stealth mode," a user will not show up in the "Who is online"
1556 listing (the RWHO server command). Only Aides may use stealth mode. The
1557 STEL command accepts one argument: a 1 indicating that the user wishes to
1558 enter stealth mode, or a 0 indicating that the user wishes to exit stealth
1559 mode. STEL returns OK if the command succeeded, ERROR+NOT_LOGGED_IN if no
1560 user is logged in, or ERROR+HIGHER_ACCESS_REQUIRED if the user is not an Aide;
1561 followed by a 1 or 0 indicating the new state.
1563 If any value other than 1 or 0 is sent by the client, the server simply
1564 replies with 1 or 0 to indicate the current state without changing it.
1566 The STEL command also makes it so a user does not show up in the chat room
1570 LBIO (List users who have BIOs on file)
1572 This command is self-explanatory. Any user who has used EBIO to place a bio
1573 on file is listed. LBIO almost always returns LISTING_FOLLOWS followed by
1574 this listing, unless it experiences an internal error in which case ERROR
1578 MSG2 (read MeSsaGe, mode 2)
1580 MSG2 follows the same calling convention as MSG0. The difference between
1581 the two commands is that MSG2 outputs messages in standard RFC822 format
1582 rather than in Citadel proprietary format.
1584 This command was implemented in order to make various gateway programs
1585 easier to implement, and to provide some sort of multimedia support in the
1586 future. Keep in mind that when this command is used, all messages will be
1587 output in fixed 80-column format.
1590 MSG3 (read MeSsaGe, mode 3 -- internal command)
1592 MSG3 is for use by internal programs only and should not be utilized by
1593 user-mode clients. It does require IPGM authentication. MSG3 follows the
1594 same calling convention as the other MSG commands, but upon success returns
1595 BINARY_FOLLOWS followed by a data block containing the _raw_ message format
1599 TERM (TERMinate another session)
1601 In a multithreaded environment, it sometimes becomes necessary to terminate
1602 a session that is unusable for whatever reason. The TERM command performs
1603 this task. Naturally, only Aides can execute TERM. The command should be
1604 called with a single argument: the session ID (obtained from an RWHO command)
1605 of the session to be terminated.
1607 TERM returns OK if the session was terminated, or ERROR otherwise. Note that
1608 a client program is prohibited from terminating the session it is currently
1614 DOWN (shut DOWN the server)
1616 This command, which may only be executed by an Aide, immediately shuts down
1617 the server. It is only implemented on servers on which such an operation is
1618 possible, such as a multithreaded Citadel engine. The server does not restart.
1619 DOWN returns OK if the user is allowed to shut down the server, in which case
1620 the client program should expect the connection to be immediately broken.
1623 SCDN (Schedule or Cancel a shutDowN)
1625 SCDN sets or clears the "scheduled shutdown" flag. Pass this command a 1 or
1626 0 to respectively set or clear the flag. When the "scheduled shutdown" flag is
1627 set, the server will be shut down when there are no longer any users logged in.
1628 Any value other than 0 or 1 will not change the flag, only report its state.
1629 No users will be kicked off the system, and in fact the server is still
1630 available for new connections. The command returns ERROR if it fails;
1631 otherwise, it returns OK followed by a number representing the current state
1635 EMSG (Enter a system MeSsaGe)
1637 This is the opposite of the MESG command - it allows the creation and editing
1638 of system messages. The only argument passed to EMSG is the name of the
1639 file being transmitted. If the file exists in any system message directory
1640 on the server it will be overwritten, otherwise a new file is created. EMSG
1641 returns SEND_LISTING on success or ERROR+HIGHER_ACCESS_REQUIRED if the user
1644 Typical client software would use MESG to retrieve any existing message into
1645 an edit buffer, then present an editor to the user and run EMSG if the changes
1649 UIMG (Upload an IMaGe file)
1651 UIMG is complemenary to OIMG; it is used to upload an image to the server.
1652 The first parameter supplied to UIMG should be 0 if the client is only checking
1653 for permission to upload, or 1 if the client is actually attempting to begin
1654 the upload operation. The second argument is the name of the file to be
1655 transmitted. In Citadel, the filename is converted to all lower case,
1656 appended with the characters ".gif", and stored in the "images" directory.
1658 UIMG returns OK if the client has permission to perform the requested upload,
1659 or ERROR+HIGHER_ACCESS_REQUIRED otherwise. If the client requested to begin
1660 the operation (first parameter set to 1), an upload file is opened, and the
1661 client should begin writing to it with WRIT commands, then close it with a
1664 The supplied filename should be one of:
1666 -> _userpic_ (Server will attempt to write to the user's online photo)
1667 -> Any of the "well known" filenames described in the writeup for the
1671 HCHG (Hostname CHanGe)
1673 HCHG is a command, usable by any user, that allows a user to change their RWHO
1674 host value. This will mask a client's originating hostname from normal
1675 users; access level 6 and higher can see, in an extended wholist, the actual
1676 hostname the user originates from.
1678 The format of an HCHG command is:
1682 If a HCHG command is successful, the value OK (200) is returned.
1685 RCHG (Roomname CHanGe)
1687 RCHG is a command, usable by any user, that allows a user to change their RWHO
1688 room value. This will mask a client's roomname from normal users; access
1689 level 6 and higher can see, in an extended wholist, the actual room the user
1692 The format of an RCHG command is:
1696 If a RCHG command is successful, the value OK (200) is returned.
1699 UCHG (Username CHanGe)
1701 UCHG is an aide-level command which allows an aide to effectively change their
1702 username. If this value is blank, the user goes into stealth mode (see
1704 will show up as being from the real username in this mode, however. In
1705 addition, the RWHO listing will include both the spoofed and real usernames.
1707 The format of an UCHG command is:
1711 If a UCHG command is successful, the value OK (200) is returned.
1714 TIME (get server local TIME)
1716 TIME returns OK followed by the current time measured in seconds since
1717 00:00:00 GMT, Jan 1, 1970 (standard Unix format).
1719 This is used in allowing a client to calculate idle times.
1722 AGUP (Administrative Get User Parameters)
1723 ASUP (Administrative Set User Parameters)
1725 These commands are only executable by Aides and by server extensions running
1726 at system-level. They are used to get/set any and all parameters relating to
1727 a user account. AGUP requires only one argument: the name of the user in
1728 question. SGUP requires all of the parameters to be set. The parameters are
1729 as follows, and are common to both commands:
1733 2 - Flags (see citadel.h)
1738 7 - Timestamp of last call
1739 8 - Purge time (in days) for this user (or 0 to use system default)
1741 Upon success, AGUP returns OK followed by all these parameters, and ASUP
1742 simply returns OK. If the client has insufficient access to perform the
1743 requested operation, ERROR+HIGHER_ACCESS_REQUIRED is returned. If the
1744 requested user does not exist, ERROR+NO_SUCH_USER is returned.
1748 GPEX (Get Policy for message EXpiration)
1750 Returns the policy of the current room, floor, or site regarding the automatic
1751 purging (expiration) of messages. The following policies are available:
1752 0 - Fall back to the policy of the next higher level. If this is a room,
1753 use the floor's default policy. If this is a floor, use the system
1754 default policy. This is an invalid value for the system policy.
1755 1 - Do not purge messages automatically.
1756 2 - Purge by message count. (Requires a value: number of messages)
1757 3 - Purge by message age. (Requires a value: number of days)
1759 The format of this command is: GPEX <which>
1760 The value of <which> must be one of: "room" "floor" "site" "mailboxes"
1762 If successful, GPEX returns OK followed by <policy>|<value>.
1766 SPEX (Set Policy for message EXpiration)
1768 Sets the policy of the current room, floor, or site regarding the automatic
1769 purging (expiration) of messages. See the writeup for the GPEX command for
1770 the list of available policies.
1772 The format of this command is: SPEX <which>|<policy>|<value>
1773 The value of <which> must be one of: "room" "floor" "site" "mailboxes"
1775 If successful, GPEX returns OK; otherwise, an ERROR code is returned.
1779 CONF (get or set global CONFiguration options)
1781 Retrieves or sets various system-wide configuration and policy options. This
1782 command is only available to Aides. The sole parameter accepted is a command,
1783 which should be either GET or SET. If the GET command succeeds, CONF will
1784 return LISTING_FOLLOWS followed by the fields described below, one line at a
1785 time. If the SET command succeeds, CONF will return SEND_LISTING and expect
1786 the fields described below, one line at a time (don't worry about other fields
1787 being added in the future; if a 'short' configuration list is sent, the missing
1788 values at the end will be left unchanged on the system). If either command
1789 fails for any reason, ERROR is returned.
1791 The configuration lines are as follows:
1794 2. Fully qualified domain name
1795 3. Human-readable node name
1796 4. Landline telephone number of this system
1797 5. Flag (0 or 1) - creator of private room automatically becomes room aide
1798 6. Server connection idle timeout (in seconds)
1799 7. Initial access level for new users
1800 8. Flag (0 or 1) - require registration for new users
1801 9. Flag (0 or 1) - automatically move Problem User messages to twit room
1802 10. Name of twit room
1803 11. Text of <more> prompt
1804 12. Flag (0 or 1) - restrict access to Internet mail
1805 13. Geographic location of this system
1806 14. Name of the system administrator
1807 15. Number of maximum concurrent sessions allowed on the server
1808 16. (placeholder -- this field is no longer in use)
1809 17. Default purge time (in days) for users
1810 18. Default purge time (in days) for rooms
1811 19. Name of room to log instant messages to (or a zero-length name for none)
1812 20. Access level required to create rooms
1813 21. Maximum message length which may be entered into the system
1814 22. Minimum number of worker threads
1815 23. Maximum number of worker threads
1816 24. Port number for POP3 service
1817 25. Port number for SMTP service
1818 26. Flag (0 or 1) - strict RFC822 adherence - don't correct From: forgeries
1819 27. Flag (0 or 1) - allow Aides to zap (forget) rooms
1820 28. Port number for IMAP service
1821 29. How often (in seconds) to run the networker
1822 30. Flag (0 or 1) - disable self-service new user registration
1823 31. (placeholder -- this field is no longer in use)
1824 32. Hour (0 through 23) during which database auto-purge jobs are run
1825 33. Name of host where an LDAP service may be found
1826 34. Port number of LDAP service on above host
1829 37. Password for LDAP Bind DN
1830 38. Server IP address to listen on (or "0.0.0.0" for all addresses)
1831 39. Port number for SMTP MSA service
1832 40. Port number for IMAPS (SSL-encrypted IMAP)
1833 41. Port number for POP3S (SSL-encrypted POP3)
1834 42. Port number for SMTPS (SSL-encrypted SMTP)
1835 43. Flag (0 or 1) - enable full text search index
1836 44. Flag (0 or 1) - automatically cull database log files
1837 45. Flag (0 or 1) - enable IMAP "instant expunge" of deleted messages
1838 46. Flag (0 or 1) - allow unauthenticated SMTP clients to spoof my domains
1840 CONF also accepts two additional commands: GETSYS and PUTSYS followed by an
1841 arbitrary MIME type (such as application/x-citadel-internet-config) which
1842 provides a means of storing generic configuration data in the Global System
1843 Configuration room without the need to add extra get/set commands to the
1846 Please note that the LDAP-specific configs have no effect on Citadel servers
1847 in which LDAP support is not enabled.
1851 MSG4 (read MeSsaGe, mode 4 -- output in preferred MIME format)
1853 This is the equivalent of MSG0, except it's a bit smarter about messages in
1854 rich text formats. Immediately following the "text" directive, the server
1855 will output RFC822-like MIME part headers such as "Content-type:" and
1856 "Content-length:". MIME formats are chosen and/or converted based on the
1857 client's preferred format settings, which are set using the MSGP command,
1862 MSGP (set MeSsaGe Preferred MIME format)
1864 Client tells the server what MIME content types it knows how to handle, and
1865 the order in which it prefers them. This is similar to an HTTP "Accept:"
1868 The parameters to a MSGP command are the client's acceptable MIME content
1869 types, in the order it prefers them (from most preferred to least preferred).
1870 For example: MSGP text/html|text/plain
1872 The MSGP command always returns OK.
1876 OPNA (OPeN Attachment)
1878 Opens, as a download file, a component of a MIME-encoded message. The two
1879 parameters which must be passed to this command are the message number and the
1880 name of the desired section. If the message or section does not exist, an
1881 appropriate ERROR code will be returned; otherwise, if the open is successful,
1882 this command will succeed returning the same information as an OPEN command.
1885 GEXP (Get instant messages)
1887 This is a more sophisticated way of retrieving instant messages than the old
1888 PEXP method. If there are no instant messages waiting, PEXP returns ERROR;
1889 otherwise, it returns LISTING_FOLLOWS and the following arguments:
1891 0 - a boolean value telling the client whether there are any additional
1892 instant messages waiting following this one
1893 1 - a Unix-style timestamp
1894 2 - flags (see server.h for more info)
1895 3 - the name of the sender
1896 4 - the node this message originated on (for future support of PIP, ICQ, etc.)
1898 The text sent to the client will be the body of the instant message.
1900 So how does the client know there are instant messages waiting? It could
1901 execute a random GEXP every now and then. Or, it can check the byte in
1902 server return code messages, between the return code and the parameters. In
1903 much the same way as FTP uses "-" to signify a continuation, Citadel uses
1904 an "*" in this position to signify the presence of waiting instant messages.
1907 FSCK (check message base reference counts)
1909 Verify, via the long way, that all message referenmce counts are correct. If
1910 the user has permission to do this then LISTING_FOLLOWS is returned, followed
1911 by a transcript of the run. Otherwise ERROR is returned.
1914 DEXP (Disable receiving instant messages)
1916 DEXP sets or clears the "disable instant messages" flag. Pass this command a
1917 1 or 0 to respectively set or clear the flag. When the "disable instant
1918 messages" flag is set, no one except Aides may send the user instant messages.
1919 Any value other than 0 or 1 will not change the flag, only report its state.
1920 The command returns ERROR if it fails; otherwise, it returns OK followed by a
1921 number representing the current state of the flag.
1924 REQT (REQuest client Termination)
1926 Request that the specified client (or all clients) log off. Aide level
1927 access is required to run this command, otherwise ERROR+HIGHER_ACCESS_REQUIRED
1930 The REQT command accepts one parameter: the session ID of the client which
1931 should be terminated, or 0 for all clients. When successful, the REQT command
1934 It should be noted that REQT simply transmits an instant message to the
1935 specified client(s) with the EM_GO_AWAY flag set. Older clients do not honor
1936 this flag, and it is certainly possible for users to re-program their client
1937 software to ignore it. Therefore the effects of the REQT command should be
1938 considered advisory only. The recommended implementation practice is to first
1939 issue a REQT command, then wait a little while (from 30 seconds up to a few
1940 minutes) for well-behaved clients to voluntarily terminate, and then issue a
1941 TERM command to forcibly disconnect the client (or perhaps a DOWN command, if
1942 you are logging off users for the purpose of shutting down the server).
1945 SEEN (set or clear the SEEN flag for a message)
1947 Beginning with version 5.80, Citadel supports the concept of setting or
1948 clearing the "seen" flag for each individual message, instead of only allowing
1949 a "last seen" pointer. In fact, the old semantics are implemented in terms
1950 of the new semantics. This command requires two arguments: the number of the
1951 message to be set, and a 1 or 0 to set or clear the "seen" bit.
1953 This command returns OK, unless the user is not logged in or a usage error
1954 occurred, in which case it returns ERROR. Please note that no checking is
1955 done on the supplied data; if the requested message does not exist, the SEEN
1956 command simply returns OK without doing anything.
1959 GTSN (GeT the list of SeeN messages)
1961 This command retrieves the list of "seen" (as opposed to unread) messages for
1962 the current room. It returns OK followed by an IMAP-format message list.
1965 SMTP (utility commands for the SMTP gateway)
1967 This command, accessible only by Aides, supports several utility operations
1968 which examine or manipulate Citadel's SMTP support. The first command argument
1969 is a subcommand telling the server what to do. The following subcommands are
1972 SMTP mx|hostname (display all MX hosts for 'hostname')
1973 SMTP runqueue (attempt immediate delivery of all messages
1974 in the outbound SMTP queue, ignoring any
1975 retry times stored there)
1978 STLS (Start Transport Layer Security)
1980 This command starts TLS on the current connection. The current
1981 implementation uses OpenSSL on both the client and server end. For future
1982 compatibility all clients must support at least TLSv1, and servers are
1983 guaranteed to support TLSv1. During TLS negotiation (see below) the server
1984 and client may agree to use a different protocol.
1986 The server returns ERROR if it does not support SSL or SSL initialization
1987 failed on the server; otherwise it returns OK. Once the server returns OK and
1988 the client has read the response, the server and client immediately negotiate
1989 TLS (in OpenSSL, using SSL_connect() on the client and SSL_accept() on the
1990 server). If negotiation fails, the server and client should attempt to resume
1991 the session unencrypted. If either end is unable to resume the session, the
1992 connection should be closed.
1994 This command may be run at any time.
1997 GTLS (Get Transport Layer Security Status)
1999 This command returns information about the current connection. The server
2000 returns OK plus several parameters if the connection is encrypted, and ERROR
2001 if the connection is not encrypted. It is primarily used for debugging. The
2002 command may be run at any time.
2004 0 - Protocol name, e.g. "SSLv3"
2005 1 - Cipher suite name, e.g. "ADH-RC4-MD5"
2006 2 - Cipher strength bits, e.g. 128
2007 3 - Cipher strength bits actually in use, e.g. 128
2010 IGAB (Initialize Global Address Book)
2012 This command creates, or re-creates, a database of Internet e-mail addresses
2013 using the vCard information in the Global Address Book room. This procedure
2014 is normally run internally when the server determines it necessary, but is
2015 also provided as a server command to be used as a troubleshooting/maintenenance
2016 tool. Only a system Aide can run the command. It returns OK on success or
2020 QDIR (Query global DIRectory)
2022 Look up an internet address in the global directory. Any logged-in user may
2023 call QDIR with one parameter, the Internet e-mail address to look up. QDIR
2024 returns OK followed by a Citadel address if there is a match, otherwise it
2025 returns ERROR+NOT_LOGGED_IN.
2028 ISME (find out if an e-mail address IS ME)
2030 This is a quickie shortcut command to find out if a given e-mail address
2031 belongs to the user currently logged in. Its sole argument is an address to
2032 parse. The supplied address may be in any format (local, IGnet, or Internet).
2033 The command returns OK if the address belongs to the user, ERROR otherwise.
2036 VIEW (set the VIEW for a room)
2038 Set the preferred view for the current user in the current room. Please see
2039 views.txt for more information on views. The sole parameter for this command
2040 is the type of view requested. VIEW returns OK on success or ERROR on failure.
2043 QNOP (Quiet No OPeration)
2045 This command does nothing, similar to the NOOP command. However, unlike the
2046 NOOP command, it returns *absolutely no response* at all. The client has no
2047 way of knowing that the command executed. It is intended for sending
2048 "keepalives" in situations where a full NOOP would cause the client protocol
2051 Naturally, sending this command to a server that doesn't support it is an
2052 easy way to mess things up. Therefore, client software should first check
2053 the output of an INFO command to ensure that the server supports quiet noops.
2057 ICAL (Internet CALendaring commands)
2059 This command supports a number of subcommands which are used to process the
2060 calendaring/scheduling support in Citadel. Here are the subcommands which
2064 Test server for calendaring support. Always returns OK unless the server
2065 does not have the calendar module enabled.
2067 ICAL respond|msgnum|partnum|action
2068 Respond to a meeting request. 'msgnum' and 'partnum' refer to a MIME-encoded
2069 meeting invitation in the current room. 'action' must be set to either
2070 "accept" or "decline" to determine the action to take. This subcommand will
2071 return either OK or ERROR.
2073 ICAL conflicts|msgnum|partnum
2074 Determine whether an incoming VEVENT will fit in the user's calendar by
2075 checking it against the existing VEVENTs. 'msgnum' and 'partnum' refer to
2076 a MIME-encoded meeting invitation in the current room (usually the inbox).
2077 This command may return ERROR if something went wrong, but usually it will
2078 return LISTING_FOLLOWS followed by a list of zero or more conflicting
2079 events. A zero-length list means that there were no conflicts.
2081 ICAL handle_rsvp|msgnum|partnum
2082 Handle an incoming "reply" (or RSVP) to a meeting request you sent out.
2083 'msgnum' and 'partnum' refer to a MIME-encoded reply in the current room.
2084 'action' must be set to either "update" or "ignore" to determine the action
2085 to take. If the action is "update" then the server will hunt for the meeting
2086 in the user's Calendar> room, and update the status for this attendee. Either
2087 way, the reply message is deleted from the current room. This subcommand will
2088 return either OK or ERROR.
2090 ICAL freebusy|username
2091 Output the free/busy times for the requested user. If the user specified
2092 has a calendar available, this command will return LISTING_FOLLOWS and a
2093 compound VCALENDAR object. That object, in turn, will contain VEVENT
2094 objects that have been stripped of all properties except for the bare
2095 minimum needed to learn free/busy times (such as DTSTART, DTEND, and
2096 TRANSP). If there is no such user, or no calendar available, the usual
2097 ERROR codes will be returned.
2101 Readers who are paying attention will notice that there is no subcommand to
2102 send out meeting invitations. This is because that task can be handled
2103 automatically by the Citadel server. Issue this command with <bool> set to 1
2104 to enable Server Generated Invitations. In this mode, when an event is saved
2105 to the user's Calendar> room and it contains attendees, Citadel will
2106 automatically turn the event into vCalendar REQUEST messages and mail them
2107 out to all listed attendees. If for some reason the client needs to disable
2108 Server Generated Invitations, the command may be sent again with <bool> = 0.
2112 MRTG (Multi Router Traffic Grapher)
2114 Multi Router Traffic Grapher (please see http://www.mrtg.org for more info) is
2115 a tool which creates pretty graphs of network activity, usually collected from
2116 routers using SNMP. However, its ability to call external scripts has spawned
2117 a small community of people using it to graph anything which can be graphed.
2118 The MRTG command can output Citadel server activity in the format MRTG expects.
2120 This format is as follows:
2125 Line 3: uptime of system
2126 Line 4: name of system
2129 MRTG accepts two different keywords. "MRTG users" will return two variables,
2130 the number of connected users and the number of active users. "MRTG messages"
2131 will return one variable (and a zero in the second field), showing the current
2132 highest message number on the system. Any other keyword, or a missing keyword,
2133 will cause the MRTG command to return an ERROR code.
2135 Please get in touch with the Citadel developers if you wish to experiment with
2140 GNET (Get NETwork configuration for this room)
2141 SNET (Set NETwork configuration for this room)
2143 These commands get/set the network configuration for the current room. Aide
2144 or Room Aide privileges are required, otherwise an ERROR code is returned.
2145 If the command succeeds, LISTING_FOLLOWS or SEND_LISTING is returned. The
2146 network configuration for a specific room includes neighbor nodes with whom
2147 the room is shared, and mailing list recipients. The format of the network
2148 configuration is described in the file "netconfigs.txt".
2152 ASYN (ASYNchronous message support)
2154 Negotiate the use of asynchronous, or unsolicited, protocol messages. The
2155 only parameter specified should be 1 or 0 to indicate that the client can or
2156 cannot handle this type of messages. The server will reply OK followed by a
2157 1 or 0 to tell the client which mode it is now operating in.
2159 If the command is not available on the server (i.e. it returns ERROR), or
2160 if the command has not been executed by the client, it should be assumed that
2161 this mode of operation is NOT in effect.
2163 The client may also send any value other than 0 or 1 to simply cause the
2164 server to output its current state without changing it.
2166 When asynchronous protocol mode is in effect, the client MUST handle any
2167 asynchronous messages as they arrive, before doing anything else.
2171 SRCH (SeaRCH the message base)
2173 This command's implementation is incomplete and will be documented when it
2179 ASYNCHRONOUS MESSAGES
2180 ---------------------
2182 When the client protocol is operating in asynchronous mode (please refer to
2183 the writeup of the ASYN command above), the following messages may arrive at
2187 902 (instant message arriving)
2189 One or more instant messages have arrived for this client.