tor_error/lib.rs
1#![cfg_attr(docsrs, feature(doc_auto_cfg, doc_cfg))]
2#![doc = include_str!("../README.md")]
3// @@ begin lint list maintained by maint/add_warning @@
4#![allow(renamed_and_removed_lints)] // @@REMOVE_WHEN(ci_arti_stable)
5#![allow(unknown_lints)] // @@REMOVE_WHEN(ci_arti_nightly)
6#![warn(missing_docs)]
7#![warn(noop_method_call)]
8#![warn(unreachable_pub)]
9#![warn(clippy::all)]
10#![deny(clippy::await_holding_lock)]
11#![deny(clippy::cargo_common_metadata)]
12#![deny(clippy::cast_lossless)]
13#![deny(clippy::checked_conversions)]
14#![warn(clippy::cognitive_complexity)]
15#![deny(clippy::debug_assert_with_mut_call)]
16#![deny(clippy::exhaustive_enums)]
17#![deny(clippy::exhaustive_structs)]
18#![deny(clippy::expl_impl_clone_on_copy)]
19#![deny(clippy::fallible_impl_from)]
20#![deny(clippy::implicit_clone)]
21#![deny(clippy::large_stack_arrays)]
22#![warn(clippy::manual_ok_or)]
23#![deny(clippy::missing_docs_in_private_items)]
24#![warn(clippy::needless_borrow)]
25#![warn(clippy::needless_pass_by_value)]
26#![warn(clippy::option_option)]
27#![deny(clippy::print_stderr)]
28#![deny(clippy::print_stdout)]
29#![warn(clippy::rc_buffer)]
30#![deny(clippy::ref_option_ref)]
31#![warn(clippy::semicolon_if_nothing_returned)]
32#![warn(clippy::trait_duplication_in_bounds)]
33#![deny(clippy::unchecked_duration_subtraction)]
34#![deny(clippy::unnecessary_wraps)]
35#![warn(clippy::unseparated_literal_suffix)]
36#![deny(clippy::unwrap_used)]
37#![deny(clippy::mod_module_files)]
38#![allow(clippy::let_unit_value)] // This can reasonably be done for explicitness
39#![allow(clippy::uninlined_format_args)]
40#![allow(clippy::significant_drop_in_scrutinee)] // arti/-/merge_requests/588/#note_2812945
41#![allow(clippy::result_large_err)] // temporary workaround for arti#587
42#![allow(clippy::needless_raw_string_hashes)] // complained-about code is fine, often best
43#![allow(clippy::needless_lifetimes)] // See arti#1765
44#![allow(mismatched_lifetime_syntaxes)] // temporary workaround for arti#2060
45//! <!-- @@ end lint list maintained by maint/add_warning @@ -->
46
47use derive_more::Display;
48
49mod internal;
50pub use internal::*;
51
52mod report;
53pub use report::*;
54
55mod retriable;
56pub use retriable::*;
57
58mod misc;
59pub use misc::*;
60
61#[cfg(feature = "tracing")]
62pub mod tracing;
63
64/// Classification of an error arising from Arti's Tor operations
65///
66/// This `ErrorKind` should suffice for programmatic handling by most applications embedding Arti:
67/// get the kind via [`HasKind::kind`] and compare it to the expected value(s) with equality
68/// or by matching.
69///
70/// When forwarding or reporting errors, use the whole error (e.g., `TorError`), not just the kind:
71/// the error itself will contain more detail and context which is useful to humans.
72//
73// Splitting vs lumping guidelines:
74//
75// # Split on the place which caused the error
76//
77// Every ErrorKind should generally have an associated "location" in
78// which it occurred. If a problem can happen in two different
79// "locations", it should have two different ErrorKinds. (This goal
80// may be frustrated sometimes by difficulty in determining where exactly
81// a given error occurred.)
82//
83// The location of an ErrorKind should always be clear from its name. If is not
84// clear, add a location-related word to the name of the ErrorKind.
85//
86// For the purposes of this discussion, the following locations exist:
87// - Process: Our code, or the application code using it. These errors don't
88// usually need a special prefix.
89// - Host: A problem with our local computing environment. These errors
90// usually reflect trying to run under impossible circumstances (no file
91// system, no permissions, etc).
92// - Local: Another process on the same machine, or on the network between us
93// and the Tor network. Errors in this location often indicate an outage,
94// misconfiguration, or a censorship event.
95// - Tor: Anywhere within the Tor network, or connections between Tor relays.
96// The words "Exit" and "Relay" also indicate this location.
97// - Remote: Anywhere _beyond_ the Tor exit. Can be a problem in the Tor
98// exit's connection to the real internet, or with the remote host that the
99// exit is talking to. (This kind of error can also indicate that the exit
100// is lying.)
101//
102// ## Lump any locations more fine-grained than that.
103//
104// We do not split locations more finely unless there's a good reason to do so.
105// For example, we don't typically split errors within the "Tor" location based
106// on whether they happened at a guard, a directory, or an exit. (Errors with
107// "Exit" or "Guard" in their names are okay, so long as that kind of error can
108// _only_ occur at an Exit or Guard.)
109//
110// # Split based on reasonable response and semantics
111//
112// We also should split ErrorKinds based on what it's reasonable for the
113// receiver to do with them. Users may find more applications for our errors
114// than we do, so we shouldn't assume that we can predict every reasonable use
115// in advance.
116//
117// ErrorKinds should be more specific than just the locations in which they
118// happen: for example, there shouldn't be a `TorNetworkError` or
119// a `RemoteFailure`.
120//
121// # Avoid exposing implementation details
122//
123// ErrorKinds should not relate to particular code paths in the Arti codebase.
124
125#[derive(Debug, Clone, Copy, PartialEq, Eq, Display)]
126#[non_exhaustive]
127pub enum ErrorKind {
128 /// Error connecting to the Tor network
129 ///
130 /// Perhaps the local network is not working,
131 /// or perhaps the chosen relay or bridge is not working properly.
132 /// Not used for errors that occur within the Tor network, or accessing the public
133 /// internet on the far side of Tor.
134 #[display("error connecting to Tor")]
135 TorAccessFailed,
136
137 /// An attempt was made to use a Tor client for something without bootstrapping it first.
138 #[display("attempted to use unbootstrapped client")]
139 BootstrapRequired,
140
141 /// Our network directory has expired before we were able to replace it.
142 ///
143 /// This kind of error can indicate one of several possible problems:
144 /// * It can occur if the client used to be on the network, but has been
145 /// unable to make directory connections for a while.
146 /// * It can occur if the client has been suspended or sleeping for a long
147 /// time, and has suddenly woken up without having a chance to replace its
148 /// network directory.
149 /// * It can happen if the client has a sudden clock jump.
150 ///
151 /// Often, retrying after a minute or so will resolve this issue.
152 ///
153 // TODO this is pretty shonky. "try again after a minute or so", seriously?
154 //
155 /// Future versions of Arti may resolve this situation automatically without caller
156 /// intervention, possibly depending on preferences and API usage, in which case this kind of
157 /// error will never occur.
158 //
159 // TODO: We should distinguish among the actual issues here, and report a
160 // real bootstrapping problem when it exists.
161 #[display("network directory is expired.")]
162 DirectoryExpired,
163
164 /// IO error accessing local persistent state
165 ///
166 /// For example, the disk might be full, or there may be a permissions problem.
167 /// Usually the source will be [`std::io::Error`].
168 ///
169 /// Note that this kind of error only applies to problems in your `state_dir`:
170 /// problems with your cache are another kind.
171 #[display("could not read/write persistent state")]
172 PersistentStateAccessFailed,
173
174 /// We could not start up because a local resource is already being used by someone else
175 ///
176 /// Local resources include things like listening ports and state lockfiles.
177 /// (We don't use this error for "out of disk space" and the like.)
178 ///
179 /// This can occur when another process
180 /// (or another caller of Arti APIs)
181 /// is already running a facility that overlaps with the one being requested.
182 ///
183 /// For example,
184 /// running multiple processes each containing instances of the same hidden service,
185 /// using the same state directories etc., is not supported.
186 ///
187 /// Another example:
188 /// if Arti is configured to listen on a particular port,
189 /// but another process on the system is already listening there,
190 /// the resulting error has kind `LocalResourceAlreadyInUse`.
191 // Actually, we only currently listen on ports in `arti` so we don't return
192 // any Rust errors for this situation at all, at the time of writing.
193 #[display("local resource (port, lockfile, etc.) already in use")]
194 LocalResourceAlreadyInUse,
195
196 /// We encountered a problem with filesystem permissions.
197 ///
198 /// This is likeliest to be caused by permissions on a file or directory
199 /// being too permissive; the next likeliest cause is that we were unable to
200 /// check the permissions on the file or directory, or on one of its
201 /// ancestors.
202 #[display("problem with filesystem permissions")]
203 FsPermissions,
204
205 /// Tor client's persistent state has been corrupted
206 ///
207 /// This could be because of a bug in the Tor code, or because something
208 /// else has been messing with the data.
209 ///
210 /// This might also occur if the Tor code was upgraded and the new Tor is
211 /// not compatible.
212 ///
213 /// Note that this kind of error only applies to problems in your
214 /// `state_dir`: problems with your cache are another kind.
215 #[display("corrupted data in persistent state")]
216 PersistentStateCorrupted,
217
218 /// Tor client's cache has been corrupted.
219 ///
220 /// This could be because of a bug in the Tor code, or because something else has been messing
221 /// with the data.
222 ///
223 /// This might also occur if the Tor code was upgraded and the new Tor is not compatible.
224 ///
225 /// Note that this kind of error only applies to problems in your `cache_dir`:
226 /// problems with your persistent state are another kind.
227 #[display("corrupted data in cache")]
228 CacheCorrupted,
229
230 /// We had a problem reading or writing to our data cache.
231 ///
232 /// This may be a disk error, a file permission error, or similar.
233 ///
234 /// Note that this kind of error only applies to problems in your `cache_dir`:
235 /// problems with your persistent state are another kind.
236 #[display("cache access problem")]
237 CacheAccessFailed,
238
239 /// The keystore has been corrupted
240 ///
241 /// This could be because of a bug in the Tor code, or because something else has been messing
242 /// with the data.
243 ///
244 /// Note that this kind of error only applies to problems in your `keystore_dir`:
245 /// problems with your cache or persistent state are another kind.
246 #[display("corrupted data in keystore")]
247 KeystoreCorrupted,
248
249 /// IO error accessing keystore
250 ///
251 /// For example, the disk might be full, or there may be a permissions problem.
252 /// The source is typically an [`std::io::Error`].
253 ///
254 /// Note that this kind of error only applies to problems in your `keystore_dir`:
255 /// problems with your cache or persistent state are another kind.
256 #[display("could not access keystore")]
257 KeystoreAccessFailed,
258
259 /// Tor client's Rust async reactor is shutting down.
260 ///
261 /// This likely indicates that the reactor has encountered a fatal error, or
262 /// has been told to do a clean shutdown, and it isn't possible to spawn new
263 /// tasks.
264 #[display("reactor is shutting down")]
265 ReactorShuttingDown,
266
267 /// Tor client is shutting down.
268 ///
269 /// This likely indicates that the last handle to the `TorClient` has been
270 /// dropped, and is preventing other operations from completing.
271 #[display("Tor client is shutting down.")]
272 ArtiShuttingDown,
273
274 /// This Tor client software is missing some feature that is recommended
275 /// (or required) for operation on the network.
276 ///
277 /// This occurs when the directory authorities tell us that we ought to have
278 /// a particular protocol feature that we do not support.
279 /// The correct solution is likely to upgrade to a more recent version of Arti.
280 #[display("Software version is deprecated")]
281 SoftwareDeprecated,
282
283 /// An operation failed because we waited too long for an exit to do
284 /// something.
285 ///
286 /// This error can happen if the host you're trying to connect to isn't
287 /// responding to traffic.
288 /// It can also happen if an exit, or hidden service, is overloaded, and
289 /// unable to answer your replies in a timely manner.
290 ///
291 /// And it might simply mean that the Tor network itself
292 /// (including possibly relays, or hidden service introduction or rendezvous points)
293 /// is not working properly
294 ///
295 /// In either case, trying later, or on a different circuit, might help.
296 //
297 // TODO: Say that this is distinct from the case where the exit _tells you_
298 // that there is a timeout.
299 #[display("operation timed out at exit")]
300 RemoteNetworkTimeout,
301
302 /// One or more configuration values were invalid or incompatible.
303 ///
304 /// This kind of error can happen if the user provides an invalid or badly
305 /// formatted configuration file, if some of the options in that file are
306 /// out of their ranges or unparsable, or if the options are not all
307 /// compatible with one another. It can also happen if configuration options
308 /// provided via APIs are out of range.
309 ///
310 /// If this occurs because of user configuration, it's probably best to tell
311 /// the user about the error. If it occurs because of API usage, it's
312 /// probably best to fix the code that causes the error.
313 #[display("invalid configuration")]
314 InvalidConfig,
315
316 /// Tried to change the configuration of a running Arti service in a way
317 /// that isn't supported.
318 ///
319 /// This kind of error can happen when you call a `reconfigure()` method on
320 /// a service (or part of a service) and the new configuration is not
321 /// compatible with the previous configuration.
322 ///
323 /// The only available remedy is to tear down the service and make a fresh
324 /// one (for example, by making a new `TorClient`).
325 #[display("invalid configuration transition")]
326 InvalidConfigTransition,
327
328 /// Tried to look up a directory depending on the user's home directory, but
329 /// the user's home directory isn't set or can't be found.
330 ///
331 /// This kind of error can also occur if we're running in an environment
332 /// where users don't have home directories.
333 ///
334 /// To resolve this kind of error, either move to an OS with home
335 /// directories, or make sure that all paths in the configuration are set
336 /// explicitly, and do not depend on any path variables.
337 #[display("could not find a home directory")]
338 NoHomeDirectory,
339
340 /// A requested operation was not implemented by Arti.
341 ///
342 /// This kind of error can happen when requesting a piece of protocol
343 /// functionality that has not (yet) been implemented in the Arti project.
344 ///
345 /// If it happens as a result of a user activity, it's fine to ignore, log,
346 /// or report the error. If it happens as a result of direct API usage, it
347 /// may indicate that you're using something that isn't implemented yet.
348 ///
349 /// This kind can relate both to operations which we plan to implement, and
350 /// to operations which we do not. It does not relate to facilities which
351 /// are disabled (e.g. at build time) or harmful.
352 ///
353 /// It can refer to facilities which were once implemented in Tor or Arti
354 /// but for which support has been removed.
355 #[display("operation not implemented")]
356 NotImplemented,
357
358 /// A feature was requested which has been disabled in this build of Arti.
359 ///
360 /// This kind of error happens when the running Arti was built without the
361 /// appropriate feature (usually, cargo feature) enabled.
362 ///
363 /// This might indicate that the overall running system has been
364 /// mis-configured at build-time. Alternatively, it can occur if the
365 /// running system is deliberately stripped down, in which case it might be
366 /// reasonable to simply report this error to a user.
367 #[display("operation not supported because Arti feature disabled")]
368 FeatureDisabled,
369
370 /// Someone or something local violated a network protocol.
371 ///
372 /// This kind of error can happen when a local program accessing us over some
373 /// other protocol violates the protocol's requirements.
374 ///
375 /// This usually indicates a programming error: either in that program's
376 /// implementation of the protocol, or in ours. In any case, the problem
377 /// is with software on the local system (or otherwise sharing a Tor client).
378 ///
379 /// It might also occur if the local system has an incompatible combination
380 /// of tools that we can't talk with.
381 ///
382 /// This error kind does *not* include situations that are better explained
383 /// by a local program simply crashing or terminating unexpectedly.
384 #[display("local protocol violation (local bug or incompatibility)")]
385 LocalProtocolViolation,
386
387 /// Someone or something on the Tor network violated the Tor protocols.
388 ///
389 /// This kind of error can happen when a remote Tor instance behaves in a
390 /// way we don't expect.
391 ///
392 /// It usually indicates a programming error: either in their implementation
393 /// of the protocol, or in ours. It can also indicate an attempted attack,
394 /// though that can be hard to diagnose.
395 #[display("Tor network protocol violation (bug, incompatibility, or attack)")]
396 TorProtocolViolation,
397
398 /// Something went wrong with a network connection or the local network.
399 ///
400 /// This kind of error is usually safe to retry, and shouldn't typically be
401 /// seen. By the time it reaches the caller, a more specific error type
402 /// should typically be available.
403 #[display("problem with network or connection")]
404 LocalNetworkError,
405
406 /// More of a local resource was needed, than is available (or than we are allowed)
407 ///
408 /// For example, we tried to use more memory than permitted by our memory quota.
409 #[display("local resource exhausted")]
410 LocalResourceExhausted,
411
412 /// A problem occurred when launching or communicating with an external
413 /// process running on this computer.
414 #[display("an externally launched plug-in tool failed")]
415 ExternalToolFailed,
416
417 /// A relay had an identity other than the one we expected.
418 ///
419 /// This could indicate a MITM attack, but more likely indicates that the
420 /// relay has changed its identity but the new identity hasn't propagated
421 /// through the directory system yet.
422 #[display("identity mismatch")]
423 RelayIdMismatch,
424
425 /// An attempt to do something remotely through the Tor network failed
426 /// because the circuit it was using shut down before the operation could
427 /// finish.
428 #[display("circuit collapsed")]
429 CircuitCollapse,
430
431 /// An operation timed out on the tor network.
432 ///
433 /// This may indicate a network problem, either with the local network
434 /// environment's ability to contact the Tor network, or with the Tor
435 /// network itself.
436 #[display("tor operation timed out")]
437 TorNetworkTimeout,
438
439 /// We tried but failed to download a piece of directory information.
440 ///
441 /// This is a lower-level kind of error; in general it should be retried
442 /// before the user can see it. In the future it is likely to be split
443 /// into several other kinds.
444 // TODO ^
445 #[display("directory fetch attempt failed")]
446 TorDirectoryError,
447
448 /// An operation finished because a remote stream was closed successfully.
449 ///
450 /// This can indicate that the target server closed the TCP connection,
451 /// or that the exit told us that it closed the TCP connection.
452 /// Callers should generally treat this like a closed TCP connection.
453 #[display("remote stream closed")]
454 RemoteStreamClosed,
455
456 /// An operation finished because the remote stream was closed abruptly.
457 ///
458 /// This kind of error is analogous to an ECONNRESET error; it indicates
459 /// that the exit reported that the stream was terminated without a clean
460 /// TCP shutdown.
461 ///
462 /// For most purposes, it's fine to treat this kind of error the same as
463 /// regular unexpected close.
464 #[display("remote stream reset")]
465 RemoteStreamReset,
466
467 /// An operation finished because a remote stream was closed unsuccessfully.
468 ///
469 /// This indicates that the exit reported some error message for the stream.
470 ///
471 /// We only provide this error kind when no more specific kind is available.
472 #[display("remote stream error")]
473 RemoteStreamError,
474
475 /// A stream failed, and the exit reports that the remote host refused
476 /// the connection.
477 ///
478 /// This is analogous to an ECONNREFUSED error.
479 #[display("remote host refused connection")]
480 RemoteConnectionRefused,
481
482 /// A stream was rejected by the exit relay because of that relay's exit
483 /// policy.
484 ///
485 /// (In Tor, exits have a set of policies declaring which addresses and
486 /// ports they're willing to connect to. Clients download only _summaries_
487 /// of these policies, so it's possible to be surprised by an exit's refusal
488 /// to connect somewhere.)
489 #[display("rejected by exit policy")]
490 ExitPolicyRejected,
491
492 /// An operation failed, and the exit reported that it waited too long for
493 /// the operation to finish.
494 ///
495 /// This kind of error is distinct from `RemoteNetworkTimeout`, which means
496 /// that _our own_ timeout threshold was violated.
497 #[display("timeout at exit relay")]
498 ExitTimeout,
499
500 /// An operation failed, and the exit reported a network failure of some
501 /// kind.
502 ///
503 /// This kind of error can occur for a number of reasons. If it happens
504 /// when trying to open a stream, it usually indicates a problem connecting,
505 /// such as an ENOROUTE error.
506 #[display("network failure at exit")]
507 RemoteNetworkFailed,
508
509 /// An operation finished because an exit failed to look up a hostname.
510 ///
511 /// Unfortunately, the Tor protocol does not distinguish failure of DNS
512 /// services ("we couldn't find out if this host exists and what its name is")
513 /// from confirmed denials ("this is not a hostname"). So this kind
514 /// conflates both those sorts of error.
515 ///
516 /// Trying at another exit might succeed, or the address might truly be
517 /// unresolvable.
518 #[display("remote hostname not found")]
519 RemoteHostNotFound,
520
521 /// The target hidden service (`.onion` service) was not found in the directory
522 ///
523 /// We successfully connected to at least one directory server,
524 /// but it didn't have a record of the hidden service.
525 ///
526 /// This probably means that the hidden service is not running, or does not exist.
527 /// (It might mean that the directory servers are faulty,
528 /// and that the hidden service was unable to publish its descriptor.)
529 #[display("Onion Service not found")]
530 OnionServiceNotFound,
531
532 /// The target hidden service (`.onion` service) seems to be down
533 ///
534 /// We successfully obtained a hidden service descriptor for the service,
535 /// so we know it is supposed to exist,
536 /// but we weren't able to communicate with it via any of its
537 /// introduction points.
538 ///
539 /// This probably means that the hidden service is not running.
540 /// (It might mean that the introduction point relays are faulty.)
541 #[display("Onion Service not running")]
542 OnionServiceNotRunning,
543
544 /// Protocol trouble involving the target hidden service (`.onion` service)
545 ///
546 /// Something unexpected happened when trying to connect to the selected hidden service.
547 /// It seems to have been due to the hidden service violating the Tor protocols somehow.
548 #[display("Onion Service protocol failed (apparently due to service behaviour)")]
549 OnionServiceProtocolViolation,
550
551 /// The target hidden service (`.onion` service) is running but we couldn't connect to it,
552 /// and we aren't sure whose fault that is
553 ///
554 /// This might be due to malfunction on the part of the service,
555 /// or a relay being used as an introduction point or relay,
556 /// or failure of the underlying Tor network.
557 #[display("Onion Service not reachable (due to service, or Tor network, behaviour)")]
558 OnionServiceConnectionFailed,
559
560 /// We tried to connect to an onion service without authentication,
561 /// but it apparently requires authentication.
562 #[display("Onion service required authentication, but none was provided.")]
563 OnionServiceMissingClientAuth,
564
565 /// We tried to connect to an onion service that requires authentication, and
566 /// ours is wrong.
567 ///
568 /// This likely means that we need to use a different key for talking to
569 /// this onion service, or that it has revoked our permissions to reach it.
570 #[display("Onion service required authentication, but provided authentication was incorrect.")]
571 OnionServiceWrongClientAuth,
572
573 /// We tried to parse a `.onion` address, and found that it was not valid.
574 ///
575 /// This likely means that it was corrupted somewhere along its way from its
576 /// origin to our API surface. It may be the wrong length, have invalid
577 /// characters, have an invalid version number, or have an invalid checksum.
578 #[display(".onion address was invalid.")]
579 OnionServiceAddressInvalid,
580
581 /// An resolve operation finished with an error.
582 ///
583 /// Contrary to [`RemoteHostNotFound`](ErrorKind::RemoteHostNotFound),
584 /// this can't mean "this is not a hostname".
585 /// This error should be retried.
586 #[display("remote hostname lookup failure")]
587 RemoteHostResolutionFailed,
588
589 /// Trouble involving a protocol we're using with a peer on the far side of the Tor network
590 ///
591 /// We were using a higher-layer protocol over a Tor connection,
592 /// and something went wrong.
593 /// This might be an error reported by the remote host within that higher protocol,
594 /// or a problem detected locally but relating to that higher protocol.
595 ///
596 /// The nature of the problem can vary:
597 /// examples could include:
598 /// failure to agree suitable parameters (incompatibility);
599 /// authentication problems (eg, TLS certificate trouble);
600 /// protocol violation by the peer;
601 /// peer refusing to provide service;
602 /// etc.
603 #[display("remote protocol violation")]
604 RemoteProtocolViolation,
605
606 /// An operation failed, and the relay in question reported that it's too
607 /// busy to answer our request.
608 #[display("relay too busy")]
609 RelayTooBusy,
610
611 /// We were asked to make an anonymous connection to a malformed address.
612 ///
613 /// This is probably because of a bad input from a user.
614 #[display("target address was invalid")]
615 InvalidStreamTarget,
616
617 /// We were asked to make an anonymous connection to a _locally_ disabled
618 /// address.
619 ///
620 /// For example, this kind of error can happen when try to connect to (e.g.)
621 /// `127.0.0.1` using a client that isn't configured with allow_local_addrs.
622 ///
623 /// Usually this means that you intended to reject the request as
624 /// nonsensical; but if you didn't, it probably means you should change your
625 /// configuration to allow what you want.
626 #[display("target address disabled locally")]
627 ForbiddenStreamTarget,
628
629 /// An operation failed in a transient way.
630 ///
631 /// This kind of error indicates that some kind of operation failed in a way
632 /// where retrying it again could likely have made it work.
633 ///
634 /// You should not generally see this kind of error returned directly to you
635 /// for high-level functions. It should only be returned from lower-level
636 /// crates that do not automatically retry these failures.
637 // Errors with this kind should generally not return a `HasRetryTime::retry_time()` of `Never`.
638 #[display("un-retried transient failure")]
639 TransientFailure,
640
641 /// Bug, for example calling a function with an invalid argument.
642 ///
643 /// This kind of error is usually a programming mistake on the caller's part.
644 /// This is usually a bug in code calling Arti, but it might be a bug in Arti itself.
645 //
646 // Usually, use `bad_api_usage!` and `into_bad_api_usage!` and thereby `InternalError`,
647 // rather than inventing a new type with this kind.
648 //
649 // Errors with this kind should generally include a stack trace. They are
650 // very like InternalError, in that they represent a bug in the program.
651 // The difference is that an InternalError, with kind `Internal`, represents
652 // a bug in arti, whereas errors with kind BadArgument represent bugs which
653 // could be (often, are likely to be) outside arti.
654 #[display("bad API usage (bug)")]
655 BadApiUsage,
656
657 /// We asked a relay to create or extend a circuit, and it declined.
658 ///
659 /// Either it gave an error message indicating that it refused to perform
660 /// the request, or the protocol gives it no room to explain what happened.
661 ///
662 /// This error is returned by higher-level functions only if it is the most informative
663 /// error after appropriate retries etc.
664 #[display("remote host refused our request")]
665 CircuitRefused,
666
667 /// We were unable to construct a path through the Tor network.
668 ///
669 /// Usually this indicates that there are too many user-supplied
670 /// restrictions for us to comply with.
671 ///
672 /// On test networks, it likely indicates that there aren't enough relays,
673 /// or that there aren't enough relays in distinct families.
674 //
675 // TODO: in the future, errors of this type should distinguish between
676 // cases where this happens because of a user restriction and cases where it
677 // happens because of a severely broken directory.
678 //
679 // The latter should be classified as TorDirectoryBroken.
680 #[display("could not construct a path")]
681 NoPath,
682
683 /// We were unable to find an exit relay with a certain set of desired
684 /// properties.
685 ///
686 /// Usually this indicates that there were too many user-supplied
687 /// restrictions on the exit for us to comply with, or that there was no
688 /// exit on the network supporting all of the ports that the user asked for.
689 //
690 // TODO: same as for NoPath.
691 #[display("no exit available for path")]
692 NoExit,
693
694 /// The Tor consensus directory is broken or unsuitable
695 ///
696 /// This could occur when running very old software
697 /// against the current Tor network,
698 /// so that the newer network is incompatible.
699 ///
700 /// It might also mean a catastrophic failure of the Tor network,
701 /// or that a deficient test network is in use.
702 ///
703 /// Currently some instances of this kind of problem
704 /// are reported as `NoPath` or `NoExit`.
705 #[display("Tor network consensus directory is not usable")]
706 TorDirectoryUnusable,
707
708 /// An operation failed because of _possible_ clock skew.
709 ///
710 /// The broken clock may be ours, or it may belong to another party on the
711 /// network. It's also possible that somebody else is lying about the time,
712 /// caching documents for far too long, or something like that.
713 #[display("possible clock skew detected")]
714 ClockSkew,
715
716 /// Internal error (bug) in Arti.
717 ///
718 /// A supposedly impossible problem has arisen. This indicates a bug in
719 /// Arti; if the Arti version is relatively recent, please report the bug on
720 /// our [bug tracker](https://gitlab.torproject.org/tpo/core/arti/-/issues).
721 #[display("internal error (bug)")]
722 Internal,
723
724 /// Unclassified error
725 ///
726 /// Some other error occurred, which does not fit into any of the other kinds.
727 ///
728 /// This kind is provided for use by external code
729 /// hooking into or replacing parts of Arti.
730 /// It is never returned by the code in Arti (`arti-*` and `tor-*` crates).
731 #[display("unclassified error")]
732 Other,
733}
734
735/// Errors that can be categorized as belonging to an [`ErrorKind`]
736///
737/// The most important implementation of this trait is
738/// `arti_client::TorError`; however, other internal errors throughout Arti
739/// also implement it.
740pub trait HasKind {
741 /// Return the kind of this error.
742 fn kind(&self) -> ErrorKind;
743}
744
745#[cfg(feature = "futures")]
746impl HasKind for futures::task::SpawnError {
747 fn kind(&self) -> ErrorKind {
748 use ErrorKind as EK;
749 if self.is_shutdown() {
750 EK::ReactorShuttingDown
751 } else {
752 EK::Internal
753 }
754 }
755}
756
757impl HasKind for void::Void {
758 fn kind(&self) -> ErrorKind {
759 void::unreachable(*self)
760 }
761}
762
763impl HasKind for std::convert::Infallible {
764 fn kind(&self) -> ErrorKind {
765 unreachable!()
766 }
767}
768
769/// Sealed
770mod sealed {
771 /// Sealed
772 pub trait Sealed {}
773}