3 TC: A Tor control protocol (Version 1)
7 This document describes an implementation-specific protocol that is used
8 for other programs (such as frontend user-interfaces) to communicate with a
9 locally running Tor process. It is not part of the Tor onion routing
12 This protocol replaces version 0 of TC, which is now deprecated. For
13 reference, TC is described in "control-spec-v0.txt". Implementors are
14 recommended to avoid using TC directly, but instead to use a library that
15 can easily be updated to use the newer protocol. (Version 0 is used by Tor
16 versions 0.1.0.x; the protocol in this document only works with Tor
17 versions in the 0.1.1.x series and later.)
21 TC is a bidirectional message-based protocol. It assumes an underlying
22 stream for communication between a controlling process (the "client"
23 or "controller") and a Tor process (or "server"). The stream may be
24 implemented via TCP, TLS-over-TCP, a Unix-domain socket, or so on,
25 but it must provide reliable in-order delivery. For security, the
26 stream should not be accessible by untrusted parties.
28 In TC, the client and server send typed messages to each other over the
29 underlying stream. The client sends "commands" and the server sends
32 By default, all messages from the server are in response to messages from
33 the client. Some client requests, however, will cause the server to send
34 messages to the client indefinitely far into the future. Such
35 "asynchronous" replies are marked as such.
37 Servers respond to messages in the order messages are received.
41 2.1. Description format
43 The message formats listed below use ABNF as described in RFC 2234.
44 The protocol itself is loosely based on SMTP (see RFC 2821).
46 We use the following nonterminals from RFC 2822: atom, qcontent
48 We define the following general-use nonterminals:
50 String = DQUOTE *qcontent DQUOTE
52 There are explicitly no limits on line length. All 8-bit characters are
53 permitted unless explicitly disallowed.
55 Wherever CRLF is specified to be accepted from the controller, Tor MAY also
56 accept LF. Tor, however, MUST NOT generate LF instead of CRLF.
57 Controllers SHOULD always send CRLF.
59 2.2. Commands from controller to Tor
61 Command = Keyword Arguments CRLF / "+" Keyword Arguments CRLF Data
63 Arguments = *(SP / VCHAR)
65 Specific commands and their arguments are described below in section 3.
67 2.3. Replies from Tor to the controller
69 Reply = SyncReply / AsyncReply
70 SyncReply = *(MidReplyLine / DataReplyLine) EndReplyLine
71 AsyncReply = *(MidReplyLine / DataReplyLine) EndReplyLine
73 MidReplyLine = StatusCode "-" ReplyLine
74 DataReplyLine = StatusCode "+" ReplyLine Data
75 EndReplyLine = StatusCode SP ReplyLine
76 ReplyLine = [ReplyText] CRLF
80 Specific replies are mentioned below in section 3, and described more fully
83 [Compatibility note: versions of Tor before 0.2.0.3-alpha sometimes
84 generate AsyncReplies of the form "*(MidReplyLine / DataReplyLine)".
85 This is incorrect, but controllers that need to work with these
86 versions of Tor should be prepared to get multi-line AsyncReplies with
87 the final line (usually "650 OK") omitted.]
89 2.4. General-use tokens
91 ; Identifiers for servers.
92 ServerID = Nickname / Fingerprint
94 Nickname = 1*19 NicknameChar
95 NicknameChar = "a"-"z" / "A"-"Z" / "0" - "9"
96 Fingerprint = "$" 40*HEXDIG
98 ; A "=" indicates that the given nickname is canonical; a "~" indicates
99 ; that the given nickname is not canonical.
100 LongName = Fingerprint [ ( "=" / "~" ) Nickname ]
102 ; How a controller tells Tor about a particular OR. There are four
104 ; $Digest -- The router whose identity key hashes to the given digest.
105 ; This is the preferred way to refer to an OR.
106 ; $Digest~Name -- The router whose identity key hashes to the given
107 ; digest, but only if the router has the given nickname.
108 ; $Digest=Name -- The router whose identity key hashes to the given
109 ; digest, but only if the router is Named and has the given
111 ; Name -- The Named router with the given nickname, or, if no such
112 ; router exists, any router whose nickname matches the one given.
113 ; This is not a safe way to refer to routers, since Named status
114 ; could under some circumstances change over time.
115 ServerSpec = LongName / Nickname
117 ; Unique identifiers for streams or circuits. Currently, Tor only
118 ; uses digits, but this may change
119 StreamID = 1*16 IDChar
120 CircuitID = 1*16 IDChar
121 IDChar = ALPHA / DIGIT
123 Address = ip4-address / ip6-address / hostname (XXXX Define these)
125 ; A "Data" section is a sequence of octets concluded by the terminating
126 ; sequence CRLF "." CRLF. The terminating sequence may not appear in the
127 ; body of the data. Leading periods on lines in the data are escaped with
128 ; an additional leading period as in RFC 2821 section 4.5.2.
129 Data = *DataLine "." CRLF
130 DataLine = CRLF / "." 1*LineItem CRLF / NonDotItem *LineItem CRLF
131 LineItem = NonCR / 1*CR NonCRLF
132 NonDotItem = NonDotCR / 1*CR NonCRLF
136 All commands are case-insensitive, but most keywords are case-sensitive.
140 Change the value of one or more configuration variables. The syntax is:
142 "SETCONF" 1*(SP keyword ["=" value]) CRLF
143 value = String / QuotedString
145 Tor behaves as though it had just read each of the key-value pairs
146 from its configuration file. Keywords with no corresponding values have
147 their configuration values reset to 0 or NULL (use RESETCONF if you want
148 to set it back to its default). SETCONF is all-or-nothing: if there
149 is an error in any of the configuration settings, Tor sets none of them.
151 Tor responds with a "250 configuration values set" reply on success.
152 If some of the listed keywords can't be found, Tor replies with a
153 "552 Unrecognized option" message. Otherwise, Tor responds with a
154 "513 syntax error in configuration values" reply on syntax error, or a
155 "553 impossible configuration setting" reply on a semantic error.
157 When a configuration option takes multiple values, or when multiple
158 configuration keys form a context-sensitive group (see GETCONF below), then
159 setting _any_ of the options in a SETCONF command is taken to reset all of
160 the others. For example, if two ORBindAddress values are configured, and a
161 SETCONF command arrives containing a single ORBindAddress value, the new
162 command's value replaces the two old values.
164 Somtimes it is not possible to change configuration options solely by
165 issuing a series of SETCONF commands, because the value of one of the
166 configuration options depends on the value of another which has not yet
167 been set. Such situations can be overcome by setting multiple configuration
168 options with a single SETCONF command (e.g. SETCONF ORPort=443
169 ORListenAddress=9001).
173 Remove all settings for a given configuration option entirely, assign
174 its default value (if any), and then assign the String provided.
175 Typically the String is left empty, to simply set an option back to
176 its default. The syntax is:
178 "RESETCONF" 1*(SP keyword ["=" String]) CRLF
180 Otherwise it behaves like SETCONF above.
184 Request the value of a configuration variable. The syntax is:
186 "GETCONF" 1*(SP keyword) CRLF
188 If all of the listed keywords exist in the Tor configuration, Tor replies
189 with a series of reply lines of the form:
191 If any option is set to a 'default' value semantically different from an
192 empty string, Tor may reply with a reply line of the form:
195 Value may be a raw value or a quoted string. Tor will try to use
196 unquoted values except when the value could be misinterpreted through
199 If some of the listed keywords can't be found, Tor replies with a
200 "552 unknown configuration keyword" message.
202 If an option appears multiple times in the configuration, all of its
203 key-value pairs are returned in order.
205 Some options are context-sensitive, and depend on other options with
206 different keywords. These cannot be fetched directly. Currently there
207 is only one such option: clients should use the "HiddenServiceOptions"
208 virtual keyword to get all HiddenServiceDir, HiddenServicePort,
209 HiddenServiceNodes, and HiddenServiceExcludeNodes option settings.
213 Request the server to inform the client about interesting events. The
216 "SETEVENTS" [SP "EXTENDED"] *(SP EventCode) CRLF
218 EventCode = "CIRC" / "STREAM" / "ORCONN" / "BW" / "DEBUG" /
219 "INFO" / "NOTICE" / "WARN" / "ERR" / "NEWDESC" / "ADDRMAP" /
220 "AUTHDIR_NEWDESCS" / "DESCCHANGED" / "STATUS_GENERAL" /
221 "STATUS_CLIENT" / "STATUS_SERVER" / "GUARD" / "NS" / "STREAM_BW"
223 Any events *not* listed in the SETEVENTS line are turned off; thus, sending
224 SETEVENTS with an empty body turns off all event reporting.
226 The server responds with a "250 OK" reply on success, and a "552
227 Unrecognized event" reply if one of the event codes isn't recognized. (On
228 error, the list of active event codes isn't changed.)
230 If the flag string "EXTENDED" is provided, Tor may provide extra
231 information with events for this connection; see 4.1 for more information.
232 NOTE: All events on a given connection will be provided in extended format,
234 NOTE: "EXTENDED" is only supported in Tor 0.1.1.9-alpha or later.
236 Each event is described in more detail in Section 4.1.
240 Sent from the client to the server. The syntax is:
241 "AUTHENTICATE" [ SP 1*HEXDIG / QuotedString ] CRLF
243 The server responds with "250 OK" on success or "515 Bad authentication" if
244 the authentication cookie is incorrect. Tor closes the connection on an
245 authentication failure.
247 The format of the 'cookie' is implementation-dependent; see 5.1 below for
248 information on how the standard Tor implementation handles it.
250 Before the client has authenticated, no command other than PROTOCOLINFO,
251 AUTHENTICATE, or QUIT is valid. If the controller sends any other command,
252 or sends a malformed command, or sends an unsuccessful AUTHENTICATE
253 command, or sends PROTOCOLINFO more than once, Tor sends an error reply and
254 closes the connection.
256 (Versions of Tor before 0.1.2.16 and 0.2.0.4-alpha did not close the
257 connection after an authentication failure.)
261 Sent from the client to the server. The syntax is:
264 Instructs the server to write out its config options into its torrc. Server
265 returns "250 OK" if successful, or "551 Unable to write configuration
266 to disk" if it can't write the file or some other error occurs.
270 Sent from the client to the server. The syntax is:
272 "SIGNAL" SP Signal CRLF
274 Signal = "RELOAD" / "SHUTDOWN" / "DUMP" / "DEBUG" / "HALT" /
275 "HUP" / "INT" / "USR1" / "USR2" / "TERM" / "NEWNYM" /
278 The meaning of the signals are:
280 RELOAD -- Reload: reload config items, refetch directory. (like HUP)
281 SHUTDOWN -- Controlled shutdown: if server is an OP, exit immediately.
282 If it's an OR, close listeners and exit after 30 seconds.
284 DUMP -- Dump stats: log information about open connections and
285 circuits. (like USR1)
286 DEBUG -- Debug: switch all open logs to loglevel debug. (like USR2)
287 HALT -- Immediate shutdown: clean up and exit now. (like TERM)
288 CLEARDNSCACHE -- Forget the client-side cached IPs for all hostnames.
289 NEWNYM -- Switch to clean circuits, so new application requests
290 don't share any circuits with old ones. Also clears
291 the client-side DNS cache. (Tor MAY rate-limit its
292 response to this signal.)
294 The server responds with "250 OK" if the signal is recognized (or simply
295 closes the socket if it was asked to close immediately), or "552
296 Unrecognized signal" if the signal is unrecognized.
300 Sent from the client to the server. The syntax is:
302 "MAPADDRESS" 1*(Address "=" Address SP) CRLF
304 The first address in each pair is an "original" address; the second is a
305 "replacement" address. The client sends this message to the server in
306 order to tell it that future SOCKS requests for connections to the original
307 address should be replaced with connections to the specified replacement
308 address. If the addresses are well-formed, and the server is able to
309 fulfill the request, the server replies with a 250 message:
310 250-OldAddress1=NewAddress1
311 250 OldAddress2=NewAddress2
313 containing the source and destination addresses. If request is
314 malformed, the server replies with "512 syntax error in command
315 argument". If the server can't fulfill the request, it replies with
316 "451 resource exhausted".
318 The client may decline to provide a body for the original address, and
319 instead send a special null address ("0.0.0.0" for IPv4, "::0" for IPv6, or
320 "." for hostname), signifying that the server should choose the original
321 address itself, and return that address in the reply. The server
322 should ensure that it returns an element of address space that is unlikely
323 to be in actual use. If there is already an address mapped to the
324 destination address, the server may reuse that mapping.
326 If the original address is already mapped to a different address, the old
327 mapping is removed. If the original address and the destination address
328 are the same, the server removes any mapping in place for the original
332 C: MAPADDRESS 0.0.0.0=torproject.org 1.2.3.4=tor.freehaven.net
333 S: 250-127.192.10.10=torproject.org
334 S: 250 1.2.3.4=tor.freehaven.net
336 {Note: This feature is designed to be used to help Tor-ify applications
337 that need to use SOCKS4 or hostname-less SOCKS5. There are three
338 approaches to doing this:
339 1. Somehow make them use SOCKS4a or SOCKS5-with-hostnames instead.
340 2. Use tor-resolve (or another interface to Tor's resolve-over-SOCKS
341 feature) to resolve the hostname remotely. This doesn't work
342 with special addresses like x.onion or x.y.exit.
343 3. Use MAPADDRESS to map an IP address to the desired hostname, and then
344 arrange to fool the application into thinking that the hostname
345 has resolved to that IP.
346 This functionality is designed to help implement the 3rd approach.}
348 Mappings set by the controller last until the Tor process exits:
349 they never expire. If the controller wants the mapping to last only
350 a certain time, then it must explicitly un-map the address when that
355 Sent from the client to the server. The syntax is as for GETCONF:
356 "GETINFO" 1*(SP keyword) CRLF
357 one or more NL-terminated strings. The server replies with an INFOVALUE
358 message, or a 551 or 552 error.
360 Unlike GETCONF, this message is used for data that are not stored in the Tor
361 configuration file, and that may be longer than a single line. On success,
362 one ReplyLine is sent for each requested value, followed by a final 250 OK
363 ReplyLine. If a value fits on a single line, the format is:
365 If a value must be split over multiple lines, the format is:
369 Recognized keys and their values include:
371 "version" -- The version of the server's software, including the name
372 of the software. (example: "Tor 0.0.9.4")
374 "config-file" -- The location of Tor's configuration file ("torrc").
376 ["exit-policy/prepend" -- The default exit policy lines that Tor will
377 *prepend* to the ExitPolicy config option.
378 -- Never implemented. Useful?]
380 "exit-policy/default" -- The default exit policy lines that Tor will
381 *append* to the ExitPolicy config option.
383 "desc/id/<OR identity>" or "desc/name/<OR nickname>" -- the latest
384 server descriptor for a given OR, NUL-terminated.
386 "desc-annotations/id/<OR identity>" -- outputs the annotations string
387 (source, timestamp of arrival, purpose, etc) for the corresponding
388 descriptor. [First implemented in 0.2.0.13-alpha.]
390 "extra-info/digest/<digest>" -- the extrainfo document whose digest (in
391 hex) is <digest>. Only available if we're downloading extra-info
394 "ns/id/<OR identity>" or "ns/name/<OR nickname>" -- the latest router
395 status info (v2 directory style) for a given OR. Router status
397 dir-spec.txt, and reflects the current beliefs of this Tor about the
398 router in question. Like directory clients, controllers MUST
399 tolerate unrecognized flags and lines. The published date and
400 descriptor digest are those believed to be best by this Tor,
401 not necessarily those for a descriptor that Tor currently has.
402 [First implemented in 0.1.2.3-alpha.]
404 "ns/all" -- Router status info (v2 directory style) for all ORs we
405 have an opinion about, joined by newlines. [First implemented
408 "ns/purpose/<purpose>" -- Router status info (v2 directory style)
409 for all ORs of this purpose. Mostly designed for /ns/purpose/bridge
410 queries. [First implemented in 0.2.0.13-alpha.]
412 "desc/all-recent" -- the latest server descriptor for every router that
415 "network-status" -- a space-separated list (v1 directory style)
416 of all known OR identities. This is in the same format as the
417 router-status line in v1 directories; see dir-spec-v1.txt section
418 3 for details. (If VERBOSE_NAMES is enabled, the output will
419 not conform to dir-spec-v1.txt; instead, the result will be a
420 space-separated list of LongName, each preceded by a "!" if it is
421 believed to be not running.) This option is deprecated; use
424 "address-mappings/all"
425 "address-mappings/config"
426 "address-mappings/cache"
427 "address-mappings/control" -- a \r\n-separated list of address
428 mappings, each in the form of "from-address to-address expiry".
429 The 'config' key returns those address mappings set in the
430 configuration; the 'cache' key returns the mappings in the
431 client-side DNS cache; the 'control' key returns the mappings set
432 via the control interface; the 'all' target returns the mappings
433 set through any mechanism.
434 Expiry is formatted as with ADDRMAP events, except that "expiry" is
435 always a time in GMT or the string "NEVER"; see section 4.1.7.
436 First introduced in 0.2.0.3-alpha.
438 "addr-mappings/*" -- as for address-mappings/*, but without the
439 expiry portion of the value. Use of this value is deprecated
440 since 0.2.0.3-alpha; use address-mappings instead.
442 "address" -- the best guess at our external IP address. If we
443 have no guess, return a 551 error. (Added in 0.1.2.2-alpha)
445 "fingerprint" -- the contents of the fingerprint file that Tor
446 writes as a server, or a 551 if we're not a server currently.
447 (Added in 0.1.2.3-alpha)
450 A series of lines as for a circuit status event. Each line is of
452 CircuitID SP CircStatus [SP Path] CRLF
455 A series of lines as for a stream status event. Each is of the form:
456 StreamID SP StreamStatus SP CircID SP Target CRLF
459 A series of lines as for an OR connection status event. Each is of the
461 ServerID SP ORStatus CRLF
464 A series of lines listing the currently chosen entry guards, if any.
466 ServerID2 SP Status [SP ISOTime] CRLF
468 Status-with-time = ("unlisted") SP ISOTime
469 Status = ("up" / "never-connected" / "down" /
470 "unusable" / "unlisted" )
472 ServerID2 = Nickname / 40*HEXDIG
474 [From 0.1.1.4-alpha to 0.1.1.10-alpha, this was called "helper-nodes".
475 Tor still supports calling it that for now, but support will be
478 [Older versions of Tor (before 0.1.2.x-final) generated 'down' instead
479 of unlisted/unusable. Current Tors never generate 'down'.]
481 [XXXX ServerID2 differs from ServerID in not prefixing fingerprints
482 with a $. This is an implementation error. It would be nice to add
483 the $ back in if we can do so without breaking compatibility.]
486 "accounting/hibernating"
488 "accounting/bytes-left"
489 "accounting/interval-start"
490 "accounting/interval-wake"
491 "accounting/interval-end"
492 Information about accounting status. If accounting is enabled,
493 "enabled" is 1; otherwise it is 0. The "hibernating" field is "hard"
494 if we are accepting no data; "soft" if we're accepting no new
495 connections, and "awake" if we're not hibernating at all. The "bytes"
496 and "bytes-left" fields contain (read-bytes SP write-bytes), for the
497 start and the rest of the interval respectively. The 'interval-start'
498 and 'interval-end' fields are the borders of the current interval; the
499 'interval-wake' field is the time within the current interval (if any)
500 where we plan[ned] to start being active.
503 A series of lines listing the available configuration options. Each is
505 OptionName SP OptionType [ SP Documentation ] CRLF
507 OptionType = "Integer" / "TimeInterval" / "DataSize" / "Float" /
508 "Boolean" / "Time" / "CommaList" / "Dependant" / "Virtual" /
509 "String" / "LineList"
513 A series of lines listing the available GETINFO options. Each is of
515 OptionName SP Documentation CRLF
516 OptionPrefix SP Documentation CRLF
517 OptionPrefix = OptionName "/*"
520 A space-separated list of all the events supported by this version of
524 A space-separated list of all the events supported by this version of
528 Maps IP addresses to 2-letter country codes. For example,
529 "GETINFO ip-to-country/18.0.0.1" should give "US".
531 "next-circuit/IP:port"
534 "dir/status-vote/current/consensus" [added in Tor 0.2.1.6-alpha]
535 "dir/status/authority"
537 "dir/status/fp/<F1>+<F2>+<F3>"
540 "dir/server/fp/<F1>+<F2>+<F3>"
542 "dir/server/d/<D1>+<D2>+<D3>"
543 "dir/server/authority"
545 A series of lines listing directory contents, provided according to the
546 specification for the URLs listed in Section 4.4 of dir-spec.txt. Note
547 that Tor MUST NOT provide private information, such as descriptors for
548 routers not marked as general-purpose. When asked for 'authority'
549 information for which this Tor is not authoritative, Tor replies with
552 "status/circuit-established"
553 "status/enough-dir-info"
554 "status/good-server-descriptor"
556 These provide the current internal Tor values for various Tor
557 states. See Section 4.1.10 for explanations. (Only a few of the
558 status events are available as getinfo's currently. Let us know if
559 you want more exposed.)
560 "status/reachability/or"
561 0 or 1, depending on whether we've found our ORPort reachable.
562 "status/reachability/dir"
563 0 or 1, depending on whether we've found our DirPort reachable.
564 "status/reachability"
565 "OR=" ("0"/"1") SP "DIR=" ("0"/"1")
566 Combines status/reachability/*; controllers MUST ignore unrecognized
567 elements in this entry.
568 "status/bootstrap-phase"
569 Returns the most recent bootstrap phase status event
570 sent. Specifically, it returns a string starting with either
571 "NOTICE BOOTSTRAP ..." or "WARN BOOTSTRAP ...". Controllers should
572 use this getinfo when they connect or attach to Tor to learn its
573 current bootstrap state.
574 "status/version/recommended"
575 List of currently recommended versions.
576 "status/version/current"
577 Status of the current version. One of: new, old, unrecommended,
578 recommended, new in series, obsolete.
581 C: GETINFO version desc/name/moria1
582 S: 250+desc/name/moria=
583 S: [Descriptor for moria]
585 S: 250-version=Tor 0.1.1.0-alpha-cvs
590 Sent from the client to the server. The format is:
591 "EXTENDCIRCUIT" SP CircuitID SP
592 ServerSpec *("," ServerSpec)
593 [SP "purpose=" Purpose] CRLF
595 This request takes one of two forms: either the CircuitID is zero, in
596 which case it is a request for the server to build a new circuit according
597 to the specified path, or the CircuitID is nonzero, in which case it is a
598 request for the server to extend an existing circuit with that ID according
599 to the specified path.
601 If CircuitID is 0 and "purpose=" is specified, then the circuit's
602 purpose is set. Two choices are recognized: "general" and
603 "controller". If not specified, circuits are created as "general".
605 If the request is successful, the server sends a reply containing a
606 message body consisting of the CircuitID of the (maybe newly created)
607 circuit. The syntax is "250" SP "EXTENDED" SP CircuitID CRLF.
609 3.11. SETCIRCUITPURPOSE
611 Sent from the client to the server. The format is:
612 "SETCIRCUITPURPOSE" SP CircuitID SP Purpose CRLF
614 This changes the circuit's purpose. See EXTENDCIRCUIT above for details.
616 3.12. SETROUTERPURPOSE
618 Sent from the client to the server. The format is:
619 "SETROUTERPURPOSE" SP NicknameOrKey SP Purpose CRLF
621 This changes the descriptor's purpose. See +POSTDESCRIPTOR below
624 NOTE: This command was disabled and made obsolete as of Tor
625 0.2.0.8-alpha. It doesn't exist anymore, and is listed here only for
630 Sent from the client to the server. The syntax is:
631 "ATTACHSTREAM" SP StreamID SP CircuitID [SP "HOP=" HopNum] CRLF
633 This message informs the server that the specified stream should be
634 associated with the specified circuit. Each stream may be associated with
635 at most one circuit, and multiple streams may share the same circuit.
636 Streams can only be attached to completed circuits (that is, circuits that
637 have sent a circuit status 'BUILT' event or are listed as built in a
638 GETINFO circuit-status request).
640 If the circuit ID is 0, responsibility for attaching the given stream is
643 If HOP=HopNum is specified, Tor will choose the HopNumth hop in the
644 circuit as the exit node, rather than the last node in the circuit.
645 Hops are 1-indexed; generally, it is not permitted to attach to hop 1.
647 Tor responds with "250 OK" if it can attach the stream, 552 if the circuit
648 or stream didn't exist, or 551 if the stream couldn't be attached for
651 {Implementation note: Tor will close unattached streams by itself,
652 roughly two minutes after they are born. Let the developers know if
653 that turns out to be a problem.}
655 {Implementation note: By default, Tor automatically attaches streams to
656 circuits itself, unless the configuration variable
657 "__LeaveStreamsUnattached" is set to "1". Attempting to attach streams
658 via TC when "__LeaveStreamsUnattached" is false may cause a race between
659 Tor and the controller, as both attempt to attach streams to circuits.}
661 {Implementation note: You can try to attachstream to a stream that
662 has already sent a connect or resolve request but hasn't succeeded
663 yet, in which case Tor will detach the stream from its current circuit
664 before proceeding with the new attach request.}
668 Sent from the client to the server. The syntax is:
669 "+POSTDESCRIPTOR" [SP "purpose=" Purpose] [SP "cache=" Cache]
670 CRLF Descriptor CRLF "." CRLF
672 This message informs the server about a new descriptor. If Purpose is
673 specified, it must be either "general", "controller", or "bridge",
674 else we return a 552 error. The default is "general".
676 If Cache is specified, it must be either "no" or "yes", else we
677 return a 552 error. If Cache is not specified, Tor will decide for
678 itself whether it wants to cache the descriptor, and controllers
679 must not rely on its choice.
681 The descriptor, when parsed, must contain a number of well-specified
682 fields, including fields for its nickname and identity.
684 If there is an error in parsing the descriptor, the server must send a
685 "554 Invalid descriptor" reply. If the descriptor is well-formed but
686 the server chooses not to add it, it must reply with a 251 message
687 whose body explains why the server was not added. If the descriptor
688 is added, Tor replies with "250 OK".
692 Sent from the client to the server. The syntax is:
693 "REDIRECTSTREAM" SP StreamID SP Address [SP Port] CRLF
695 Tells the server to change the exit address on the specified stream. If
696 Port is specified, changes the destination port as well. No remapping
697 is performed on the new provided address.
699 To be sure that the modified address will be used, this event must be sent
700 after a new stream event is received, and before attaching this stream to
703 Tor replies with "250 OK" on success.
707 Sent from the client to the server. The syntax is:
709 "CLOSESTREAM" SP StreamID SP Reason *(SP Flag) CRLF
711 Tells the server to close the specified stream. The reason should be one
712 of the Tor RELAY_END reasons given in tor-spec.txt, as a decimal. Flags is
713 not used currently; Tor servers SHOULD ignore unrecognized flags. Tor may
714 hold the stream open for a while to flush any data that is pending.
716 Tor replies with "250 OK" on success, or a 512 if there aren't enough
717 arguments, or a 552 if it doesn't recognize the StreamID or reason.
722 CLOSECIRCUIT SP CircuitID *(SP Flag) CRLF
725 Tells the server to close the specified circuit. If "IfUnused" is
726 provided, do not close the circuit unless it is unused.
728 Other flags may be defined in the future; Tor SHOULD ignore unrecognized
731 Tor replies with "250 OK" on success, or a 512 if there aren't enough
732 arguments, or a 552 if it doesn't recognize the CircuitID.
736 Tells the server to hang up on this controller connection. This command
737 can be used before authenticating.
743 "USEFEATURE" *(SP FeatureName) CRLF
744 FeatureName = 1*(ALPHA / DIGIT / "_" / "-")
746 Sometimes extensions to the controller protocol break compatibility with
747 older controllers. In this case, whenever possible, the extensions are
748 first included in Tor disabled by default, and only enabled on a given
749 controller connection when the "USEFEATURE" command is given. Once a
750 "USEFEATURE" command is given, it applies to all subsequent interactions on
751 the same connection; to disable an enabled feature, a new controller
752 connection must be opened.
754 This is a forward-compatibility mechanism; each feature will eventually
755 become a regular part of the control protocol in some future version of Tor.
756 Tor will ignore a request to use any feature that is already on by default.
757 Tor will give a "552" error if any requested feature is not recognized.
759 Feature names are case-insensitive.
763 Same as passing 'EXTENDED' to SETEVENTS; this is the preferred way to
764 request the extended event syntax.
766 This will not be always-enabled until at least two stable releases
767 after 0.1.2.3-alpha, the release where it was first used for
772 Instead of ServerID as specified above, the controller should
773 identify ORs by LongName in events and GETINFO results. This format is
774 strictly more informative: rather than including Nickname for
775 known Named routers and Fingerprint for unknown or unNamed routers, the
776 LongName format includes a Fingerprint, an indication of Named status,
777 and a Nickname (if one is known).
779 This will not be always-enabled until at least two stable releases
780 after 0.1.2.2-alpha, the release where it was first available.
785 "RESOLVE" *Option *Address CRLF
786 Option = "mode=reverse"
787 Address = a hostname or IPv4 address
789 This command launches a remote hostname lookup request for every specified
790 request (or reverse lookup if "mode=reverse" is specified). Note that the
791 request is done in the background: to see the answers, your controller will
792 need to listen for ADDRMAP events; see 4.1.7 below.
794 [Added in Tor 0.2.0.3-alpha]
799 "PROTOCOLINFO" *(SP PIVERSION) CRLF
801 The server reply format is:
802 "250-PROTOCOLINFO" SP PIVERSION CRLF *InfoLine "250 OK" CRLF
804 InfoLine = AuthLine / VersionLine / OtherLine
806 AuthLine = "250-AUTH" SP "METHODS=" AuthMethod *(",")AuthMethod
807 *(SP "COOKIEFILE=" AuthCookieFile) CRLF
808 VersionLine = "250-VERSION" SP "Tor=" TorVersion [SP Arguments] CRLF
811 "NULL" / ; No authentication is required
812 "HASHEDPASSWORD" / ; A controller must supply the original password
813 "COOKIE" / ; A controller must supply the contents of a cookie
815 AuthCookieFile = QuotedString
816 TorVersion = QuotedString
818 OtherLine = "250-" Keyword [SP Arguments] CRLF
822 Tor MAY give its InfoLines in any order; controllers MUST ignore InfoLines
823 with keywords they do not recognize. Controllers MUST ignore extraneous
824 data on any InfoLine.
826 PIVERSION is there in case we drastically change the syntax one day. For
827 now it should always be "1". Controllers MAY provide a list of the
828 protocolinfo versions they support; Tor MAY select a version that the
829 controller does not support.
831 AuthMethod is used to specify one or more control authentication
832 methods that Tor currently accepts.
834 AuthCookieFile specifies the absolute path and filename of the
835 authentication cookie that Tor is expecting and is provided iff
836 the METHODS field contains the method "COOKIE". Controllers MUST handle
837 escape sequences inside this string.
839 The VERSION line contains the Tor version.
841 [Unlike other commands besides AUTHENTICATE, PROTOCOLINFO may be used (but
842 only once!) before AUTHENTICATE.]
844 [PROTOCOLINFO was not supported before Tor 0.2.0.5-alpha.]
848 Reply codes follow the same 3-character format as used by SMTP, with the
849 first character defining a status, the second character defining a
850 subsystem, and the third designating fine-grained information.
852 The TC protocol currently uses the following first characters:
854 2yz Positive Completion Reply
855 The command was successful; a new request can be started.
857 4yz Temporary Negative Completion reply
858 The command was unsuccessful but might be reattempted later.
860 5yz Permanent Negative Completion Reply
861 The command was unsuccessful; the client should not try exactly
862 that sequence of commands again.
864 6yz Asynchronous Reply
865 Sent out-of-order in response to an earlier SETEVENTS command.
867 The following second characters are used:
870 Sent in response to ill-formed or nonsensical commands.
873 Refers to operations of the Tor Control protocol.
876 Refers to actual operations of Tor system.
878 The following codes are defined:
881 251 Operation was unnecessary
882 [Tor has declined to perform the operation, but no harm was done.]
884 451 Resource exhausted
886 500 Syntax error: protocol
888 510 Unrecognized command
889 511 Unimplemented command
890 512 Syntax error in command argument
891 513 Unrecognized command argument
892 514 Authentication required
893 515 Bad authentication
895 550 Unspecified Tor error
898 [Something went wrong inside Tor, so that the client's
899 request couldn't be fulfilled.]
901 552 Unrecognized entity
902 [A configuration key, a stream ID, circuit ID, event,
903 mentioned in the command did not actually exist.]
905 553 Invalid configuration value
906 [The client tried to set a configuration option to an
907 incorrect, ill-formed, or impossible value.]
909 554 Invalid descriptor
913 650 Asynchronous event notification
915 Unless specified to have specific contents, the human-readable messages
916 in error replies should not be relied upon to match those in this document.
918 4.1. Asynchronous events
920 These replies can be sent after a corresponding SETEVENTS command has been
921 received. They will not be interleaved with other Reply elements, but they
922 can appear between a command and its corresponding reply. For example,
923 this sequence is possible:
927 C: GETCONF SOCKSPORT ORPORT
928 S: 650 CIRC 1000 EXTENDED moria1,moria2
929 S: 250-SOCKSPORT=9050
932 But this sequence is disallowed:
935 C: GETCONF SOCKSPORT ORPORT
936 S: 250-SOCKSPORT=9050
937 S: 650 CIRC 1000 EXTENDED moria1,moria2
940 Clients MUST tolerate more arguments in an asynchonous reply than
941 expected, and MUST tolerate more lines in an asynchronous reply than
942 expected. For instance, a client that expects a CIRC message like:
943 650 CIRC 1000 EXTENDED moria1,moria2
945 650-CIRC 1000 EXTENDED moria1,moria2 0xBEEF
949 If clients ask for extended events, then each event line as specified below
950 will be followed by additional extensions. Additional lines will be of the
952 "650" ("-"/" ") KEYWORD ["=" ARGUMENTS] CRLF
953 Additional arguments will be of the form
954 SP KEYWORD ["=" ( QuotedString / * NonSpDquote ) ]
955 Such clients MUST tolerate lines with keywords they do not recognize.
957 4.1.1. Circuit status changed
961 "650" SP "CIRC" SP CircuitID SP CircStatus [SP Path]
962 [SP "REASON=" Reason [SP "REMOTE_REASON=" Reason]] CRLF
965 "LAUNCHED" / ; circuit ID assigned to new circuit
966 "BUILT" / ; all hops finished, can now accept streams
967 "EXTENDED" / ; one more hop has been completed
968 "FAILED" / ; circuit closed (was not built)
969 "CLOSED" ; circuit closed (was built)
971 Path = ServerID *("," ServerID)
973 Reason = "NONE" / "TORPROTOCOL" / "INTERNAL" / "REQUESTED" /
974 "HIBERNATING" / "RESOURCELIMIT" / "CONNECTFAILED" /
975 "OR_IDENTITY" / "OR_CONN_CLOSED" / "TIMEOUT" /
976 "FINISHED" / "DESTROYED" / "NOPATH" / "NOSUCHSERVICE"
978 The path is provided only when the circuit has been extended at least one
981 The "REASON" field is provided only for FAILED and CLOSED events, and only
982 if extended events are enabled (see 3.19). Clients MUST accept reasons
983 not listed above. Reasons are as given in tor-spec.txt, except for:
985 NOPATH (Not enough nodes to make circuit)
987 The "REMOTE_REASON" field is provided only when we receive a DESTROY or
988 TRUNCATE cell, and only if extended events are enabled. It contains the
989 actual reason given by the remote OR for closing the circuit. Clients MUST
990 accept reasons not listed above. Reasons are as listed in tor-spec.txt.
992 4.1.2. Stream status changed
996 "650" SP "STREAM" SP StreamID SP StreamStatus SP CircID SP Target
997 [SP "REASON=" Reason [ SP "REMOTE_REASON=" Reason ]]
998 [SP "SOURCE=" Source] [ SP "SOURCE_ADDR=" Address ":" Port ]
999 [SP "PURPOSE=" Purpose]
1003 "NEW" / ; New request to connect
1004 "NEWRESOLVE" / ; New request to resolve an address
1005 "REMAP" / ; Address re-mapped to another
1006 "SENTCONNECT" / ; Sent a connect cell along a circuit
1007 "SENTRESOLVE" / ; Sent a resolve cell along a circuit
1008 "SUCCEEDED" / ; Received a reply; stream established
1009 "FAILED" / ; Stream failed and not retriable
1010 "CLOSED" / ; Stream closed
1011 "DETACHED" ; Detached from circuit; still retriable
1013 Target = Address ":" Port
1015 The circuit ID designates which circuit this stream is attached to. If
1016 the stream is unattached, the circuit ID "0" is given.
1018 Reason = "MISC" / "RESOLVEFAILED" / "CONNECTREFUSED" /
1019 "EXITPOLICY" / "DESTROY" / "DONE" / "TIMEOUT" /
1020 "HIBERNATING" / "INTERNAL"/ "RESOURCELIMIT" /
1021 "CONNRESET" / "TORPROTOCOL" / "NOTDIRECTORY" / "END"
1023 The "REASON" field is provided only for FAILED, CLOSED, and DETACHED
1024 events, and only if extended events are enabled (see 3.19). Clients MUST
1025 accept reasons not listed above. Reasons are as given in tor-spec.txt,
1028 END (We received a RELAY_END cell from the other side of this
1030 [XXXX document more. -NM]
1032 The "REMOTE_REASON" field is provided only when we receive a RELAY_END
1033 cell, and only if extended events are enabled. It contains the actual
1034 reason given by the remote OR for closing the stream. Clients MUST accept
1035 reasons not listed above. Reasons are as listed in tor-spec.txt.
1037 "REMAP" events include a Source if extended events are enabled:
1038 Source = "CACHE" / "EXIT"
1039 Clients MUST accept sources not listed above. "CACHE" is given if
1040 the Tor client decided to remap the address because of a cached
1041 answer, and "EXIT" is given if the remote node we queried gave us
1042 the new address as a response.
1044 The "SOURCE_ADDR" field is included with NEW and NEWRESOLVE events if
1045 extended events are enabled. It indicates the address and port
1046 that requested the connection, and can be (e.g.) used to look up the
1049 Purpose = "DIR_FETCH" / "UPLOAD_DESC" / "DNS_REQUEST" /
1050 "USER" / "DIRPORT_TEST"
1052 The "PURPOSE" field is provided only for NEW and NEWRESOLVE events, and
1053 only if extended events are enabled (see 3.19). Clients MUST accept
1054 purposes not listed above.
1056 4.1.3. OR Connection status changed
1059 "650" SP "ORCONN" SP (ServerID / Target) SP ORStatus [ SP "REASON="
1060 Reason ] [ SP "NCIRCS=" NumCircuits ] CRLF
1062 ORStatus = "NEW" / "LAUNCHED" / "CONNECTED" / "FAILED" / "CLOSED"
1064 NEW is for incoming connections, and LAUNCHED is for outgoing
1065 connections. CONNECTED means the TLS handshake has finished (in
1066 either direction). FAILED means a connection is being closed that
1067 hasn't finished its handshake, and CLOSED is for connections that
1070 A ServerID is specified unless it's a NEW connection, in which
1071 case we don't know what server it is yet, so we use Address:Port.
1073 If extended events are enabled (see 3.19), optional reason and
1074 circuit counting information is provided for CLOSED and FAILED
1077 Reason = "MISC" / "DONE" / "CONNECTREFUSED" /
1078 "IDENTITY" / "CONNECTRESET" / "TIMEOUT" / "NOROUTE" /
1079 "IOERROR" / "RESOURCELIMIT"
1081 NumCircuits counts both established and pending circuits.
1083 4.1.4. Bandwidth used in the last second
1086 "650" SP "BW" SP BytesRead SP BytesWritten *(SP Type "=" Num) CRLF
1088 BytesWritten = 1*DIGIT
1089 Type = "DIR" / "OR" / "EXIT" / "APP" / ...
1092 BytesRead and BytesWritten are the totals. [In a future Tor version,
1093 we may also include a breakdown of the connection types that used
1094 bandwidth this second (not implemented yet).]
1099 "650" SP Severity SP ReplyText CRLF
1101 "650+" Severity CRLF Data 650 SP "OK" CRLF
1103 Severity = "DEBUG" / "INFO" / "NOTICE" / "WARN"/ "ERR"
1105 4.1.6. New descriptors available
1108 "650" SP "NEWDESC" 1*(SP ServerID) CRLF
1110 4.1.7. New Address mapping
1113 "650" SP "ADDRMAP" SP Address SP NewAddress SP Expiry
1114 [SP Error] SP GMTExpiry CRLF
1116 NewAddress = Address / "<error>"
1117 Expiry = DQUOTE ISOTime DQUOTE / "NEVER"
1119 Error = "error=" ErrorCode
1121 GMTExpiry = "EXPIRES=" DQUOTE IsoTime DQUOTE
1123 Error and GMTExpiry are only provided if extended events are enabled.
1125 Expiry is expressed as the local time (rather than GMT). This is a bug,
1126 left in for backward compatibility; new code should look at GMTExpiry
1129 These events are generated when a new address mapping is entered in the
1130 cache, or when the answer for a RESOLVE command is found.
1132 4.1.8. Descriptors uploaded to us in our role as authoritative dirserver
1135 "650" "+" "AUTHDIR_NEWDESCS" CRLF Action CRLF Message CRLF
1136 Descriptor CRLF "." CRLF "650" SP "OK" CRLF
1137 Action = "ACCEPTED" / "DROPPED" / "REJECTED"
1140 4.1.9. Our descriptor changed
1143 "650" SP "DESCCHANGED" CRLF
1145 [First added in 0.1.2.2-alpha.]
1147 4.1.10. Status events
1149 Status events (STATUS_GENERAL, STATUS_CLIENT, and STATUS_SERVER) are sent
1150 based on occurrences in the Tor process pertaining to the general state of
1151 the program. Generally, they correspond to log messages of severity Notice
1152 or higher. They differ from log messages in that their format is a
1153 specified interface.
1156 "650" SP StatusType SP StatusSeverity SP StatusAction
1157 [SP StatusArguments] CRLF
1159 StatusType = "STATUS_GENERAL" / "STATUS_CLIENT" / "STATUS_SERVER"
1160 StatusSeverity = "NOTICE" / "WARN" / "ERR"
1161 StatusAction = 1*ALPHA
1162 StatusArguments = StatusArgument *(SP StatusArgument)
1163 StatusArgument = StatusKeyword '=' StatusValue
1164 StatusKeyword = 1*(ALNUM / "_")
1165 StatusValue = 1*(ALNUM / '_') / QuotedString
1167 Action is a string, and Arguments is a series of keyword=value
1168 pairs on the same line. Values may be space-terminated strings,
1171 These events are always produced with EXTENDED_EVENTS and
1172 VERBOSE_NAMES; see the explanations in the USEFEATURE section
1175 Controllers MUST tolerate unrecognized actions, MUST tolerate
1176 unrecognized arguments, MUST tolerate missing arguments, and MUST
1177 tolerate arguments that arrive in any order.
1179 Each event description below is accompanied by a recommendation for
1180 controllers. These recommendations are suggestions only; no controller
1181 is required to implement them.
1183 Compatibility note: versions of Tor before 0.2.0.22-rc incorrectly
1184 generated "STATUS_SERVER" as "STATUS_SEVER". To be compatible with those
1185 versions, tools should accept both.
1187 Actions for STATUS_GENERAL events can be as follows:
1191 Tor spent enough time without CPU cycles that it has closed all
1192 its circuits and will establish them anew. This typically
1193 happens when a laptop goes to sleep and then wakes up again. It
1194 also happens when the system is swapping so heavily that Tor is
1195 starving. The "time" argument specifies the number of seconds Tor
1196 thinks it was unconscious for (or alternatively, the number of
1197 seconds it went back in time).
1199 This status event is sent as NOTICE severity normally, but WARN
1200 severity if Tor is acting as a server currently.
1202 {Recommendation for controller: ignore it, since we don't really
1203 know what the user should do anyway. Hm.}
1207 "REASON=NEW/OBSOLETE/UNRECOMMENDED"
1208 "RECOMMENDED=\"version, version, ...\""
1209 Tor has found that directory servers don't recommend its version of
1210 the Tor software. RECOMMENDED is a comma-and-space-separated string
1211 of Tor versions that are recommended. REASON is NEW if this version
1212 of Tor is newer than any recommended version, OBSOLETE if
1213 this version of Tor is older than any recommended version, and
1214 UNRECOMMENDED if some recommended versions of Tor are newer and
1215 some are older than this version. (The "OBSOLETE" reason was called
1216 "OLD" from Tor 0.1.2.3-alpha up to and including 0.2.0.12-alpha.)
1218 {Controllers may want to suggest that the user upgrade OLD or
1219 UNRECOMMENDED versions. NEW versions may be known-insecure, or may
1220 simply be development versions.}
1222 TOO_MANY_CONNECTIONS
1224 Tor has reached its ulimit -n or whatever the native limit is on file
1225 descriptors or sockets. CURRENT is the number of sockets Tor
1226 currently has open. The user should really do something about
1227 this. The "current" argument shows the number of connections currently
1230 {Controllers may recommend that the user increase the limit, or
1231 increase it for them. Recommendations should be phrased in an
1232 OS-appropriate way and automated when possible.}
1236 Tor has encountered a situation that its developers never expected,
1237 and the developers would like to learn that it happened. Perhaps
1238 the controller can explain this to the user and encourage her to
1241 {Controllers should log bugs, but shouldn't annoy the user in case a
1242 bug appears frequently.}
1245 SKEW="+" / "-" SECONDS
1246 MIN_SKEW="+" / "-" SECONDS.
1247 SOURCE="DIRSERV:IP:Port" / "NETWORKSTATUS:IP:PORT" / "CONSENSUS"
1248 If "SKEW" is present, it's an estimate of how far we are from the
1249 time declared in the source. (In other words, if we're an hour in
1250 the past, the value is -3600.) "MIN_SKEW" is present, it's a lower
1251 bound. If the source is a DIRSERV, we got the current time from a
1252 connection to a dirserver. If the source is a NETWORKSTATUS, we
1253 decided we're skewed because we got a v2 networkstatus from far in
1254 the future. If the source is CONSENSUS, we decided we're skewed
1255 because we got a networkstatus consensus from the future.
1257 {Controllers may want to warn the user if the skew is high, or if
1258 multiple skew messages appear at severity WARN. Controllers
1259 shouldn't blindly adjust the clock, since the more accurate source
1260 of skew info (DIRSERV) is currently unauthenticated.}
1263 "METHOD=" libevent method
1264 "VERSION=" libevent version
1265 "BADNESS=" "BROKEN" / "BUGGY" / "SLOW"
1266 "RECOVERED=" "NO" / "YES"
1267 Tor knows about bugs in using the configured event method in this
1268 version of libevent. "BROKEN" libevents won't work at all;
1269 "BUGGY" libevents might work okay; "SLOW" libevents will work
1270 fine, but not quickly. If "RECOVERED" is YES, Tor managed to
1271 switch to a more reliable (but probably slower!) libevent method.
1273 {Controllers may want to warn the user if this event occurs, though
1274 generally it's the fault of whoever built the Tor binary and there's
1275 not much the user can do besides upgrade libevent or upgrade the
1279 Tor believes that none of the known directory servers are
1280 reachable -- this is most likely because the local network is
1281 down or otherwise not working, and might help to explain for the
1282 user why Tor appears to be broken.
1284 {Controllers may want to warn the user if this event occurs; further
1285 action is generally not possible.}
1289 Tor has received and validated a new consensus networkstatus.
1290 (This event can be delayed a little while after the consensus
1291 is received, if Tor needs to fetch certificates.)
1293 Actions for STATUS_CLIENT events can be as follows:
1302 "RECOMMENDATION=" Keyword
1305 Tor has made some progress at establishing a connection to the
1306 Tor network, fetching directory information, or making its first
1307 circuit; or it has encountered a problem while bootstrapping. This
1308 status event is especially useful for users with slow connections
1309 or with connectivity problems.
1311 "Progress" gives a number between 0 and 100 for how far through
1312 the bootstrapping process we are. "Summary" is a string that can
1313 be displayed to the user to describe the *next* task that Tor
1314 will tackle, i.e., the task it is working on after sending the
1315 status event. "Tag" is a string that controllers can use to
1316 recognize bootstrap phases, if they want to do something smarter
1317 than just blindly displaying the summary string; see Section 5
1318 for the current tags that Tor issues.
1320 The StatusSeverity describes whether this is a normal bootstrap
1321 phase (severity notice) or an indication of a bootstrapping
1322 problem (severity warn).
1324 For bootstrap problems, we include the same progress, tag, and
1325 summary values as we would for a normal bootstrap event, but we
1326 also include "warning", "reason", "count", and "recommendation"
1327 key/value combos. The "count" number tells how many bootstrap
1328 problems there have been so far at this phase. The "reason"
1329 string lists one of the reasons allowed in the ORCONN event. The
1330 "warning" argument string with any hints Tor has to offer about
1331 why it's having troubles bootstrapping.
1333 The "reason" values are long-term-stable controller-facing tags to
1334 identify particular issues in a bootstrapping step. The warning
1335 strings, on the other hand, are human-readable. Controllers
1336 SHOULD NOT rely on the format of any warning string. Currently
1337 the possible values for "recommendation" are either "ignore" or
1338 "warn" -- if ignore, the controller can accumulate the string in
1339 a pile of problems to show the user if the user asks; if warn,
1340 the controller should alert the user that Tor is pretty sure
1341 there's a bootstrapping problem.
1343 Currently Tor uses recommendation=ignore for the first
1344 nine bootstrap problem reports for a given phase, and then
1345 uses recommendation=warn for subsequent problems at that
1346 phase. Hopefully this is a good balance between tolerating
1347 occasional errors and reporting serious problems quickly.
1350 Tor now knows enough network-status documents and enough server
1351 descriptors that it's going to start trying to build circuits now.
1353 {Controllers may want to use this event to decide when to indicate
1354 progress to their users, but should not interrupt the user's browsing
1358 We discarded expired statuses and router descriptors to fall
1359 below the desired threshold of directory information. We won't
1360 try to build any circuits until ENOUGH_DIR_INFO occurs again.
1362 {Controllers may want to use this event to decide when to indicate
1363 progress to their users, but should not interrupt the user's browsing
1367 Tor is able to establish circuits for client use. This event will
1368 only be sent if we just built a circuit that changed our mind --
1369 that is, prior to this event we didn't know whether we could
1372 {Suggested use: controllers can notify their users that Tor is
1373 ready for use as a client once they see this status event. [Perhaps
1374 controllers should also have a timeout if too much time passes and
1375 this event hasn't arrived, to give tips on how to troubleshoot.
1376 On the other hand, hopefully Tor will send further status events
1377 if it can identify the problem.]}
1379 CIRCUIT_NOT_ESTABLISHED
1380 "REASON=" "EXTERNAL_ADDRESS" / "DIR_ALL_UNREACHABLE" / "CLOCK_JUMPED"
1381 We are no longer confident that we can build circuits. The "reason"
1382 keyword provides an explanation: which other status event type caused
1383 our lack of confidence.
1385 {Controllers may want to use this event to decide when to indicate
1386 progress to their users, but should not interrupt the user's browsing
1388 [Note: only REASON=CLOCK_JUMPED is implemented currently.]
1392 "RESULT=" "REJECT" / "WARN"
1393 A stream was initiated to a port that's commonly used for
1394 vulnerable-plaintext protocols. If the Result is "reject", we
1395 refused the connection; whereas if it's "warn", we allowed it.
1397 {Controllers should warn their users when this occurs, unless they
1398 happen to know that the application using Tor is in fact doing so
1399 correctly (e.g., because it is part of a distributed bundle). They
1400 might also want some sort of interface to let the user configure
1401 their RejectPlaintextPorts and WarnPlaintextPorts config options.}
1404 "PROTOCOL=" "SOCKS4" / "SOCKS5"
1406 A connection was made to Tor's SOCKS port using one of the SOCKS
1407 approaches that doesn't support hostnames -- only raw IP addresses.
1408 If the client application got this address from gethostbyname(),
1409 it may be leaking target addresses via DNS.
1411 {Controllers should warn their users when this occurs, unless they
1412 happen to know that the application using Tor is in fact doing so
1413 correctly (e.g., because it is part of a distributed bundle).}
1415 SOCKS_UNKNOWN_PROTOCOL
1417 A connection was made to Tor's SOCKS port that tried to use it
1418 for something other than the SOCKS protocol. Perhaps the user is
1419 using Tor as an HTTP proxy? The DATA is the first few characters
1420 sent to Tor on the SOCKS port.
1422 {Controllers may want to warn their users when this occurs: it
1423 indicates a misconfigured application.}
1426 "HOSTNAME=QuotedString"
1427 Some application gave us a funny-looking hostname. Perhaps
1428 it is broken? In any case it won't work with Tor and the user
1431 {Controllers may want to warn their users when this occurs: it
1432 usually indicates a misconfigured application.}
1434 Actions for STATUS_SERVER can be as follows:
1439 "METHOD=CONFIGURED/DIRSERV/RESOLVED/INTERFACE/GETHOSTNAME"
1440 Our best idea for our externally visible IP has changed to 'IP'.
1441 If 'HOSTNAME' is present, we got the new IP by resolving 'NAME'. If the
1442 method is 'CONFIGURED', the IP was given verbatim as a configuration
1443 option. If the method is 'RESOLVED', we resolved the Address
1444 configuration option to get the IP. If the method is 'GETHOSTNAME',
1445 we resolved our hostname to get the IP. If the method is 'INTERFACE',
1446 we got the address of one of our network interfaces to get the IP. If
1447 the method is 'DIRSERV', a directory server told us a guess for what
1450 {Controllers may want to record this info and display it to the user.}
1452 CHECKING_REACHABILITY
1454 "DIRADDRESS=IP:port"
1455 We're going to start testing the reachability of our external OR port
1458 {This event could affect the controller's idea of server status, but
1459 the controller should not interrupt the user to tell them so.}
1461 REACHABILITY_SUCCEEDED
1463 "DIRADDRESS=IP:port"
1464 We successfully verified the reachability of our external OR port or
1465 directory port (depending on which of ORADDRESS or DIRADDRESS is
1468 {This event could affect the controller's idea of server status, but
1469 the controller should not interrupt the user to tell them so.}
1471 GOOD_SERVER_DESCRIPTOR
1472 We successfully uploaded our server descriptor to at least one
1473 of the directory authorities, with no complaints.
1475 {This event could affect the controller's idea of server status, but
1476 the controller should not interrupt the user to tell them so.}
1480 "STATUS=" "UP" / "DOWN"
1482 One of our nameservers has changed status.
1485 {This event could affect the controller's idea of server status, but
1486 the controller should not interrupt the user to tell them so.}
1489 All of our nameservers have gone down.
1491 {This is a problem; if it happens often without the nameservers
1492 coming up again, the user needs to configure more or better
1496 Our DNS provider is providing an address when it should be saying
1497 "NOTFOUND"; Tor will treat the address as a synonym for "NOTFOUND".
1499 {This is an annoyance; controllers may want to tell admins that their
1500 DNS provider is not to be trusted.}
1503 Our DNS provider is giving a hijacked address instead of well-known
1504 websites; Tor will not try to be an exit node.
1506 {Controllers could warn the admin if the server is running as an
1507 exit server: the admin needs to configure a good DNS server.
1508 Alternatively, this happens a lot in some restrictive environments
1509 (hotels, universities, coffeeshops) when the user hasn't registered.}
1511 BAD_SERVER_DESCRIPTOR
1514 A directory authority rejected our descriptor. Possible reasons
1515 include malformed descriptors, incorrect keys, highly skewed clocks,
1518 {Controllers should warn the admin, and try to cope if they can.}
1520 ACCEPTED_SERVER_DESCRIPTOR
1522 A single directory authority accepted our descriptor.
1525 {This event could affect the controller's idea of server status, but
1526 the controller should not interrupt the user to tell them so.}
1530 "DIRADDRESS=IP:port"
1531 We failed to connect to our external OR port or directory port
1534 {This event could affect the controller's idea of server status. The
1535 controller should warn the admin and suggest reasonable steps to take.}
1537 4.1.11. Our set of guard nodes has changed
1540 "650" SP "GUARD" SP Type SP Name SP Status ... CRLF
1542 Name = The (possibly verbose) nickname of the guard affected.
1543 Status = "NEW" | "UP" | "DOWN" | "BAD" | "GOOD" | "DROPPED"
1545 [explain states. XXX]
1547 4.1.12. Network status has changed
1550 "650" "+" "NS" CRLF 1*NetworkStatus "." CRLF "650" SP "OK" CRLF
1552 [First added in 0.1.2.3-alpha]
1554 4.1.13. Bandwidth used on an application stream
1557 "650" SP "STREAM_BW" SP StreamID SP BytesRead SP BytesWritten CRLF
1559 BytesWritten = 1*DIGIT
1561 BytesRead and BytesWritten are the number of bytes read and written since
1562 the last STREAM_BW event on this stream. These events are generated about
1563 once per second per stream; no events are generated for streams that have
1564 not read or written.
1566 These events apply only to streams entering Tor (such as on a SOCKSPort,
1567 TransPort, or so on). They are not generated for exiting streams.
1569 5. Implementation notes
1573 By default, the current Tor implementation trusts all local users.
1575 If the 'CookieAuthentication' option is true, Tor writes a "magic cookie"
1576 file named "control_auth_cookie" into its data directory. To authenticate,
1577 the controller must send the contents of this file, encoded in hexadecimal.
1579 If the 'HashedControlPassword' option is set, it must contain the salted
1580 hash of a secret password. The salted hash is computed according to the
1581 S2K algorithm in RFC 2440 (OpenPGP), and prefixed with the s2k specifier.
1582 This is then encoded in hexadecimal, prefixed by the indicator sequence
1583 "16:". Thus, for example, the password 'foo' could encode to:
1584 16:660537E3E1CD49996044A3BF558097A981F539FEA2F9DA662B4626C1C2
1585 ++++++++++++++++**^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
1588 You can generate the salt of a password by calling
1589 'tor --hash-password <password>'
1590 or by using the example code in the Python and Java controller libraries.
1591 To authenticate under this scheme, the controller sends Tor the original
1592 secret that was used to generate the password, either as a quoted string
1593 or encoded in hexadecimal.
1595 5.2. Don't let the buffer get too big.
1597 If you ask for lots of events, and 16MB of them queue up on the buffer,
1598 the Tor process will close the socket.
1600 5.3. Backward compatibility with v0 control protocol.
1602 The 'version 0' control protocol was replaced in Tor 0.1.1.x. Support
1603 was removed in Tor 0.2.0.x. Every non-obsolete version of Tor now
1604 supports the version 1 control protocol.
1606 For backward compatibility with the "version 0" control protocol,
1607 Tor used to check whether the third octet of the first command is zero.
1608 (If it was, Tor assumed that version 0 is in use.)
1610 This compatibility was removed in Tor 0.1.2.16 and 0.2.0.4-alpha.
1612 5.4. Tor config options for use by controllers
1614 Tor provides a few special configuration options for use by controllers.
1615 These options can be set and examined by the SETCONF and GETCONF commands,
1616 but are not saved to disk by SAVECONF.
1618 Generally, these options make Tor unusable by disabling a portion of Tor's
1619 normal operations. Unless a controller provides replacement functionality
1620 to fill this gap, Tor will not correctly handle user requests.
1622 __AllDirOptionsPrivate
1624 If true, Tor will try to launch all directory operations through
1625 anonymous connections. (Ordinarily, Tor only tries to anonymize
1626 requests related to hidden services.) This option will slow down
1627 directory access, and may stop Tor from working entirely if it does not
1628 yet have enough directory information to build circuits.
1630 (Boolean. Default: "0".)
1632 __DisablePredictedCircuits
1634 If true, Tor will not launch preemptive "general-purpose" circuits for
1635 streams to attach to. (It will still launch circuits for testing and
1636 for hidden services.)
1638 (Boolean. Default: "0".)
1640 __LeaveStreamsUnattached
1642 If true, Tor will not automatically attach new streams to circuits;
1643 instead, the controller must attach them with ATTACHSTREAM. If the
1644 controller does not attach the streams, their data will never be routed.
1646 (Boolean. Default: "0".)
1648 __HashedControlSessionPassword
1650 As HashedControlPassword, but is not saved to the torrc file by
1651 SAVECONF. Added in Tor 0.2.0.20-rc.
1653 __ReloadTorrcOnSIGHUP
1655 If this option is true (the default), we reload the torrc from disk
1656 every time we get a SIGHUP (from the controller or via a signal).
1657 Otherwise, we don't. This option exists so that controllers can keep
1658 their options from getting overwritten when a user sends Tor a HUP for
1659 some other reason (for example, to rotate the logs).
1661 (Boolean. Default: "1")
1663 5.5. Phases from the Bootstrap status event.
1665 This section describes the various bootstrap phases currently reported
1666 by Tor. Controllers should not assume that the percentages and tags
1667 listed here will continue to match up, or even that the tags will stay
1668 in the same order. Some phases might also be skipped (not reported)
1669 if the associated bootstrap step is already complete, or if the phase
1670 no longer is necessary. Only "starting" and "done" are guaranteed to
1671 exist in all future versions.
1673 Current Tor versions enter these phases in order, monotonically.
1674 Future Tors MAY revisit earlier stages.
1677 tag=starting summary="starting"
1679 Tor starts out in this phase.
1682 tag=conn_dir summary="Connecting to directory mirror"
1684 Tor sends this event as soon as Tor has chosen a directory mirror --
1685 e.g. one of the authorities if bootstrapping for the first time or
1686 after a long downtime, or one of the relays listed in its cached
1687 directory information otherwise.
1689 Tor will stay at this phase until it has successfully established
1690 a TCP connection with some directory mirror. Problems in this phase
1691 generally happen because Tor doesn't have a network connection, or
1692 because the local firewall is dropping SYN packets.
1695 tag=handshake_dir summary="Finishing handshake with directory mirror"
1697 This event occurs when Tor establishes a TCP connection with a relay used
1698 as a directory mirror (or its https proxy if it's using one). Tor remains
1699 in this phase until the TLS handshake with the relay is finished.
1701 Problems in this phase generally happen because Tor's firewall is
1702 doing more sophisticated MITM attacks on it, or doing packet-level
1703 keyword recognition of Tor's handshake.
1706 tag=onehop_create summary="Establishing one-hop circuit for dir info"
1708 Once TLS is finished with a relay, Tor will send a CREATE_FAST cell
1709 to establish a one-hop circuit for retrieving directory information.
1710 It will remain in this phase until it receives the CREATED_FAST cell
1711 back, indicating that the circuit is ready.
1714 tag=requesting_status summary="Asking for networkstatus consensus"
1716 Once we've finished our one-hop circuit, we will start a new stream
1717 for fetching the networkstatus consensus. We'll stay in this phase
1718 until we get the 'connected' relay cell back, indicating that we've
1719 established a directory connection.
1722 tag=loading_status summary="Loading networkstatus consensus"
1724 Once we've established a directory connection, we will start fetching
1725 the networkstatus consensus document. This could take a while; this
1726 phase is a good opportunity for using the "progress" keyword to indicate
1729 This phase could stall if the directory mirror we picked doesn't
1730 have a copy of the networkstatus consensus so we have to ask another,
1731 or it does give us a copy but we don't find it valid.
1734 tag=loading_keys summary="Loading authority key certs"
1736 Sometimes when we've finished loading the networkstatus consensus,
1737 we find that we don't have all the authority key certificates for the
1738 keys that signed the consensus. At that point we put the consensus we
1739 fetched on hold and fetch the keys so we can verify the signatures.
1742 tag=requesting_descriptors summary="Asking for relay descriptors"
1744 Once we have a valid networkstatus consensus and we've checked all
1745 its signatures, we start asking for relay descriptors. We stay in this
1746 phase until we have received a 'connected' relay cell in response to
1747 a request for descriptors.
1750 tag=loading_descriptors summary="Loading relay descriptors"
1752 We will ask for relay descriptors from several different locations,
1753 so this step will probably make up the bulk of the bootstrapping,
1754 especially for users with slow connections. We stay in this phase until
1755 we have descriptors for at least 1/4 of the usable relays listed in
1756 the networkstatus consensus. This phase is also a good opportunity to
1757 use the "progress" keyword to indicate partial steps.
1760 tag=conn_or summary="Connecting to entry guard"
1762 Once we have a valid consensus and enough relay descriptors, we choose
1763 some entry guards and start trying to build some circuits. This step
1764 is similar to the "conn_dir" phase above; the only difference is
1767 If a Tor starts with enough recent cached directory information,
1768 its first bootstrap status event will be for the conn_or phase.
1771 tag=handshake_or summary="Finishing handshake with entry guard"
1773 This phase is similar to the "handshake_dir" phase, but it gets reached
1774 if we finish a TCP connection to a Tor relay and we have already reached
1775 the "conn_or" phase. We'll stay in this phase until we complete a TLS
1776 handshake with a Tor relay.
1779 tag=circuit_create "Establishing circuits"
1781 Once we've finished our TLS handshake with an entry guard, we will
1782 set about trying to make some 3-hop circuits in case we need them soon.
1785 tag=done summary="Done"
1787 A full 3-hop exit circuit has been established. Tor is ready to handle
1788 application connections now.