1 /* Copyright (c) 2001 Matej Pfajfar.
2 * Copyright (c) 2001-2004, Roger Dingledine.
3 * Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
4 * Copyright (c) 2007-2010, The Tor Project, Inc. */
5 /* See LICENSE for licensing information */
9 * \brief The actual details of building circuits.
12 #define CIRCUIT_PRIVATE
20 #define MIN(a,b) ((a)<(b)?(a):(b))
23 #define CBT_BIN_TO_MS(bin) ((bin)*CBT_BIN_WIDTH + (CBT_BIN_WIDTH/2))
25 /********* START VARIABLES **********/
26 /** Global list of circuit build times */
27 // FIXME: Add this as a member for entry_guard_t instead of global?
28 // Then we could do per-guard statistics, as guards are likely to
29 // vary in their own latency. The downside of this is that guards
30 // can change frequently, so we'd be building a lot more circuits
32 circuit_build_times_t circ_times
;
34 /** A global list of all circuits at this hop. */
35 extern circuit_t
*global_circuitlist
;
37 /** An entry_guard_t represents our information about a chosen long-term
38 * first hop, known as a "helper" node in the literature. We can't just
39 * use a routerinfo_t, since we want to remember these even when we
40 * don't have a directory. */
42 char nickname
[MAX_NICKNAME_LEN
+1];
43 char identity
[DIGEST_LEN
];
44 time_t chosen_on_date
; /**< Approximately when was this guard added?
45 * "0" if we don't know. */
46 char *chosen_by_version
; /**< What tor version added this guard? NULL
47 * if we don't know. */
48 unsigned int made_contact
: 1; /**< 0 if we have never connected to this
49 * router, 1 if we have. */
50 unsigned int can_retry
: 1; /**< Should we retry connecting to this entry,
51 * in spite of having it marked as unreachable?*/
52 time_t bad_since
; /**< 0 if this guard is currently usable, or the time at
53 * which it was observed to become (according to the
54 * directory or the user configuration) unusable. */
55 time_t unreachable_since
; /**< 0 if we can connect to this guard, or the
56 * time at which we first noticed we couldn't
58 time_t last_attempted
; /**< 0 if we can connect to this guard, or the time
59 * at which we last failed to connect to it. */
62 /** A list of our chosen entry guards. */
63 static smartlist_t
*entry_guards
= NULL
;
64 /** A value of 1 means that the entry_guards list has changed
65 * and those changes need to be flushed to disk. */
66 static int entry_guards_dirty
= 0;
68 /** If set, we're running the unit tests: we should avoid clobbering
69 * our state file or accessing get_options() or get_or_state() */
70 static int unit_tests
= 0;
72 /********* END VARIABLES ************/
74 static int circuit_deliver_create_cell(circuit_t
*circ
,
75 uint8_t cell_type
, const char *payload
);
76 static int onion_pick_cpath_exit(origin_circuit_t
*circ
, extend_info_t
*exit
);
77 static crypt_path_t
*onion_next_hop_in_cpath(crypt_path_t
*cpath
);
78 static int onion_extend_cpath(origin_circuit_t
*circ
);
79 static int count_acceptable_routers(smartlist_t
*routers
);
80 static int onion_append_hop(crypt_path_t
**head_ptr
, extend_info_t
*choice
);
82 static void entry_guards_changed(void);
85 circuit_build_times_disabled(void)
90 int consensus_disabled
= networkstatus_get_param(NULL
, "cbtdisabled",
92 int config_disabled
= !get_options()->LearnCircuitBuildTimeout
;
93 int dirauth_disabled
= get_options()->AuthoritativeDir
;
94 int state_disabled
= (get_or_state()->LastWritten
== -1);
96 if (consensus_disabled
|| config_disabled
|| dirauth_disabled
||
99 "CircuitBuildTime learning is disabled. "
100 "Consensus=%d, Config=%d, AuthDir=%d, StateFile=%d",
101 consensus_disabled
, config_disabled
, dirauth_disabled
,
111 circuit_build_times_max_timeouts(void)
113 int32_t num
= networkstatus_get_param(NULL
, "cbtmaxtimeouts",
114 CBT_DEFAULT_MAX_RECENT_TIMEOUT_COUNT
);
119 circuit_build_times_default_num_xm_modes(void)
121 int32_t num
= networkstatus_get_param(NULL
, "cbtnummodes",
122 CBT_DEFAULT_NUM_XM_MODES
);
127 circuit_build_times_min_circs_to_observe(void)
129 int32_t num
= networkstatus_get_param(NULL
, "cbtmincircs",
130 CBT_DEFAULT_MIN_CIRCUITS_TO_OBSERVE
);
135 circuit_build_times_quantile_cutoff(void)
137 int32_t num
= networkstatus_get_param(NULL
, "cbtquantile",
138 CBT_DEFAULT_QUANTILE_CUTOFF
);
143 circuit_build_times_close_quantile(void)
145 int32_t num
= networkstatus_get_param(NULL
, "cbtclosequantile",
146 CBT_DEFAULT_CLOSE_QUANTILE
);
152 circuit_build_times_test_frequency(void)
154 int32_t num
= networkstatus_get_param(NULL
, "cbttestfreq",
155 CBT_DEFAULT_TEST_FREQUENCY
);
160 circuit_build_times_min_timeout(void)
162 int32_t num
= networkstatus_get_param(NULL
, "cbtmintimeout",
163 CBT_DEFAULT_TIMEOUT_MIN_VALUE
);
168 circuit_build_times_initial_timeout(void)
170 int32_t num
= networkstatus_get_param(NULL
, "cbtinitialtimeout",
171 CBT_DEFAULT_TIMEOUT_INITIAL_VALUE
);
176 circuit_build_times_recent_circuit_count(void)
178 int32_t num
= networkstatus_get_param(NULL
, "cbtrecentcount",
179 CBT_DEFAULT_RECENT_CIRCUITS
);
184 * This function is called when we get a consensus update.
186 * It checks to see if we have changed any consensus parameters
187 * that require reallocation or discard of previous stats.
190 circuit_build_times_new_consensus_params(circuit_build_times_t
*cbt
,
193 int32_t num
= networkstatus_get_param(ns
, "cbtrecentcount",
194 CBT_DEFAULT_RECENT_CIRCUITS
);
196 if (num
> 0 && num
!= cbt
->liveness
.num_recent_circs
) {
197 int8_t *recent_circs
;
198 log_notice(LD_CIRC
, "Changing recent timeout size from %d to %d",
199 cbt
->liveness
.num_recent_circs
, num
);
201 tor_assert(cbt
->liveness
.timeouts_after_firsthop
);
204 * Technically this is a circular array that we are reallocating
205 * and memcopying. However, since it only consists of either 1s
206 * or 0s, and is only used in a statistical test to determine when
207 * we should discard our history after a sufficient number of 1's
208 * have been reached, it is fine if order is not preserved or
211 * cbtrecentcount should only be changing in cases of severe network
212 * distress anyway, so memory correctness here is paramount over
213 * doing acrobatics to preserve the array.
215 recent_circs
= tor_malloc_zero(sizeof(int8_t)*num
);
216 memcpy(recent_circs
, cbt
->liveness
.timeouts_after_firsthop
,
217 sizeof(int8_t)*MIN(num
, cbt
->liveness
.num_recent_circs
));
219 // Adjust the index if it needs it.
220 if (num
< cbt
->liveness
.num_recent_circs
) {
221 cbt
->liveness
.after_firsthop_idx
= MIN(num
-1,
222 cbt
->liveness
.after_firsthop_idx
);
225 tor_free(cbt
->liveness
.timeouts_after_firsthop
);
226 cbt
->liveness
.timeouts_after_firsthop
= recent_circs
;
227 cbt
->liveness
.num_recent_circs
= num
;
231 /** Make a note that we're running unit tests (rather than running Tor
232 * itself), so we avoid clobbering our state file. */
234 circuitbuild_running_unit_tests(void)
240 * Return the initial default or configured timeout in milliseconds
243 circuit_build_times_get_initial_timeout(void)
246 if (!unit_tests
&& get_options()->CircuitBuildTimeout
) {
247 timeout
= get_options()->CircuitBuildTimeout
*1000;
248 if (timeout
< circuit_build_times_min_timeout()) {
249 log_warn(LD_CIRC
, "Config CircuitBuildTimeout too low. Setting to %ds",
250 circuit_build_times_min_timeout()/1000);
251 timeout
= circuit_build_times_min_timeout();
254 timeout
= circuit_build_times_initial_timeout();
260 * Reset the build time state.
262 * Leave estimated parameters, timeout and network liveness intact
266 circuit_build_times_reset(circuit_build_times_t
*cbt
)
268 memset(cbt
->circuit_build_times
, 0, sizeof(cbt
->circuit_build_times
));
269 cbt
->total_build_times
= 0;
270 cbt
->build_times_idx
= 0;
271 cbt
->have_computed_timeout
= 0;
275 * Initialize the buildtimes structure for first use.
277 * Sets the initial timeout value based to either the
278 * config setting or BUILD_TIMEOUT_INITIAL_VALUE.
281 circuit_build_times_init(circuit_build_times_t
*cbt
)
283 memset(cbt
, 0, sizeof(*cbt
));
284 cbt
->liveness
.num_recent_circs
= circuit_build_times_recent_circuit_count();
285 cbt
->liveness
.timeouts_after_firsthop
= tor_malloc_zero(sizeof(int8_t)*
286 cbt
->liveness
.num_recent_circs
);
287 cbt
->close_ms
= cbt
->timeout_ms
= circuit_build_times_get_initial_timeout();
288 control_event_buildtimeout_set(cbt
, BUILDTIMEOUT_SET_EVENT_RESET
);
292 * Rewind our build time history by n positions.
295 circuit_build_times_rewind_history(circuit_build_times_t
*cbt
, int n
)
299 cbt
->build_times_idx
-= n
;
300 cbt
->build_times_idx
%= CBT_NCIRCUITS_TO_OBSERVE
;
302 for (i
= 0; i
< n
; i
++) {
303 cbt
->circuit_build_times
[(i
+cbt
->build_times_idx
)
304 %CBT_NCIRCUITS_TO_OBSERVE
]=0;
307 if (cbt
->total_build_times
> n
) {
308 cbt
->total_build_times
-= n
;
310 cbt
->total_build_times
= 0;
314 "Rewound history by %d places. Current index: %d. "
315 "Total: %d", n
, cbt
->build_times_idx
, cbt
->total_build_times
);
319 * Add a new build time value <b>time</b> to the set of build times. Time
320 * units are milliseconds.
322 * circuit_build_times <b>cbt</a> is a circular array, so loop around when
326 circuit_build_times_add_time(circuit_build_times_t
*cbt
, build_time_t time
)
328 if (time
<= 0 || time
> CBT_BUILD_TIME_MAX
) {
329 log_warn(LD_BUG
, "Circuit build time is too large (%u)."
330 "This is probably a bug.", time
);
331 tor_fragile_assert();
335 log_debug(LD_CIRC
, "Adding circuit build time %u", time
);
337 cbt
->circuit_build_times
[cbt
->build_times_idx
] = time
;
338 cbt
->build_times_idx
= (cbt
->build_times_idx
+ 1) % CBT_NCIRCUITS_TO_OBSERVE
;
339 if (cbt
->total_build_times
< CBT_NCIRCUITS_TO_OBSERVE
)
340 cbt
->total_build_times
++;
342 if ((cbt
->total_build_times
% CBT_SAVE_STATE_EVERY
) == 0) {
343 /* Save state every n circuit builds */
344 if (!unit_tests
&& !get_options()->AvoidDiskWrites
)
345 or_state_mark_dirty(get_or_state(), 0);
352 * Return maximum circuit build time
355 circuit_build_times_max(circuit_build_times_t
*cbt
)
358 build_time_t max_build_time
= 0;
359 for (i
= 0; i
< CBT_NCIRCUITS_TO_OBSERVE
; i
++) {
360 if (cbt
->circuit_build_times
[i
] > max_build_time
361 && cbt
->circuit_build_times
[i
] != CBT_BUILD_ABANDONED
)
362 max_build_time
= cbt
->circuit_build_times
[i
];
364 return max_build_time
;
368 /** Return minimum circuit build time */
370 circuit_build_times_min(circuit_build_times_t
*cbt
)
373 build_time_t min_build_time
= CBT_BUILD_TIME_MAX
;
374 for (i
= 0; i
< CBT_NCIRCUITS_TO_OBSERVE
; i
++) {
375 if (cbt
->circuit_build_times
[i
] && /* 0 <-> uninitialized */
376 cbt
->circuit_build_times
[i
] < min_build_time
)
377 min_build_time
= cbt
->circuit_build_times
[i
];
379 if (min_build_time
== CBT_BUILD_TIME_MAX
) {
380 log_warn(LD_CIRC
, "No build times less than CBT_BUILD_TIME_MAX!");
382 return min_build_time
;
387 * Calculate and return a histogram for the set of build times.
389 * Returns an allocated array of histrogram bins representing
390 * the frequency of index*CBT_BIN_WIDTH millisecond
391 * build times. Also outputs the number of bins in nbins.
393 * The return value must be freed by the caller.
396 circuit_build_times_create_histogram(circuit_build_times_t
*cbt
,
400 build_time_t max_build_time
= circuit_build_times_max(cbt
);
403 *nbins
= 1 + (max_build_time
/ CBT_BIN_WIDTH
);
404 histogram
= tor_malloc_zero(*nbins
* sizeof(build_time_t
));
406 // calculate histogram
407 for (i
= 0; i
< CBT_NCIRCUITS_TO_OBSERVE
; i
++) {
408 if (cbt
->circuit_build_times
[i
] == 0
409 || cbt
->circuit_build_times
[i
] == CBT_BUILD_ABANDONED
)
410 continue; /* 0 <-> uninitialized */
412 c
= (cbt
->circuit_build_times
[i
] / CBT_BIN_WIDTH
);
420 * Return the Pareto start-of-curve parameter Xm.
422 * Because we are not a true Pareto curve, we compute this as the
423 * weighted average of the N=3 most frequent build time bins.
426 circuit_build_times_get_xm(circuit_build_times_t
*cbt
)
428 build_time_t i
, nbins
;
429 build_time_t
*nth_max_bin
;
430 int32_t bin_counts
=0;
431 build_time_t ret
= 0;
432 uint32_t *histogram
= circuit_build_times_create_histogram(cbt
, &nbins
);
434 int num_modes
= circuit_build_times_default_num_xm_modes();
436 // Only use one mode if < 1000 buildtimes. Not enough data
438 if (cbt
->total_build_times
< CBT_NCIRCUITS_TO_OBSERVE
)
441 nth_max_bin
= (build_time_t
*)tor_malloc_zero(num_modes
*sizeof(build_time_t
));
443 for (i
= 0; i
< nbins
; i
++) {
444 if (histogram
[i
] >= histogram
[nth_max_bin
[0]]) {
448 for (n
= 1; n
< num_modes
; n
++) {
449 if (histogram
[i
] >= histogram
[nth_max_bin
[n
]] &&
450 (!histogram
[nth_max_bin
[n
-1]]
451 || histogram
[i
] < histogram
[nth_max_bin
[n
-1]])) {
457 for (n
= 0; n
< num_modes
; n
++) {
458 bin_counts
+= histogram
[nth_max_bin
[n
]];
459 ret
+= CBT_BIN_TO_MS(nth_max_bin
[n
])*histogram
[nth_max_bin
[n
]];
460 log_info(LD_CIRC
, "Xm mode #%d: %u %u", n
, CBT_BIN_TO_MS(nth_max_bin
[n
]),
461 histogram
[nth_max_bin
[n
]]);
466 tor_free(nth_max_bin
);
472 * Output a histogram of current circuit build times to
473 * the or_state_t state structure.
476 circuit_build_times_update_state(circuit_build_times_t
*cbt
,
481 build_time_t nbins
= 0;
482 config_line_t
**next
, *line
;
484 histogram
= circuit_build_times_create_histogram(cbt
, &nbins
);
486 config_free_lines(state
->BuildtimeHistogram
);
487 next
= &state
->BuildtimeHistogram
;
490 state
->TotalBuildTimes
= cbt
->total_build_times
;
491 state
->CircuitBuildAbandonedCount
= 0;
493 for (i
= 0; i
< CBT_NCIRCUITS_TO_OBSERVE
; i
++) {
494 if (cbt
->circuit_build_times
[i
] == CBT_BUILD_ABANDONED
)
495 state
->CircuitBuildAbandonedCount
++;
498 for (i
= 0; i
< nbins
; i
++) {
499 // compress the histogram by skipping the blanks
500 if (histogram
[i
] == 0) continue;
501 *next
= line
= tor_malloc_zero(sizeof(config_line_t
));
502 line
->key
= tor_strdup("CircuitBuildTimeBin");
503 line
->value
= tor_malloc(25);
504 tor_snprintf(line
->value
, 25, "%d %d",
505 CBT_BIN_TO_MS(i
), histogram
[i
]);
506 next
= &(line
->next
);
510 if (!get_options()->AvoidDiskWrites
)
511 or_state_mark_dirty(get_or_state(), 0);
518 * Shuffle the build times array.
520 * Stolen from http://en.wikipedia.org/wiki/Fisher\u2013Yates_shuffle
523 circuit_build_times_shuffle_and_store_array(circuit_build_times_t
*cbt
,
524 build_time_t
*raw_times
,
528 if (num_times
> CBT_NCIRCUITS_TO_OBSERVE
) {
529 log_notice(LD_CIRC
, "Decreasing circuit_build_times size from %d to %d",
530 num_times
, CBT_NCIRCUITS_TO_OBSERVE
);
533 /* This code can only be run on a compact array */
535 int k
= crypto_rand_int(n
+ 1); /* 0 <= k <= n. */
536 build_time_t tmp
= raw_times
[k
];
537 raw_times
[k
] = raw_times
[n
];
541 /* Since the times are now shuffled, take a random CBT_NCIRCUITS_TO_OBSERVE
542 * subset (ie the first CBT_NCIRCUITS_TO_OBSERVE values) */
543 for (n
= 0; n
< MIN(num_times
, CBT_NCIRCUITS_TO_OBSERVE
); n
++) {
544 circuit_build_times_add_time(cbt
, raw_times
[n
]);
549 * Filter old synthetic timeouts that were created before the
550 * new right-censored Pareto calculation was deployed.
552 * Once all clients before 0.2.1.13-alpha are gone, this code
556 circuit_build_times_filter_timeouts(circuit_build_times_t
*cbt
)
558 int num_filtered
=0, i
=0;
559 double timeout_rate
= 0;
560 build_time_t max_timeout
= 0;
562 timeout_rate
= circuit_build_times_timeout_rate(cbt
);
563 max_timeout
= (build_time_t
)cbt
->close_ms
;
565 for (i
= 0; i
< CBT_NCIRCUITS_TO_OBSERVE
; i
++) {
566 if (cbt
->circuit_build_times
[i
] > max_timeout
) {
567 build_time_t replaced
= cbt
->circuit_build_times
[i
];
569 cbt
->circuit_build_times
[i
] = CBT_BUILD_ABANDONED
;
571 log_debug(LD_CIRC
, "Replaced timeout %d with %d", replaced
,
572 cbt
->circuit_build_times
[i
]);
577 "We had %d timeouts out of %d build times, "
578 "and filtered %d above the max of %u",
579 (int)(cbt
->total_build_times
*timeout_rate
),
580 cbt
->total_build_times
, num_filtered
, max_timeout
);
586 * Load histogram from <b>state</b>, shuffling the resulting array
587 * after we do so. Use this result to estimate parameters and
588 * calculate the timeout.
590 * Returns -1 and sets msg on error. Msg must be freed by the caller.
593 circuit_build_times_parse_state(circuit_build_times_t
*cbt
,
594 or_state_t
*state
, char **msg
)
597 uint32_t loaded_cnt
= 0, N
= 0;
600 build_time_t
*loaded_times
;
601 circuit_build_times_init(cbt
);
604 if (circuit_build_times_disabled()) {
608 /* build_time_t 0 means uninitialized */
609 loaded_times
= tor_malloc_zero(sizeof(build_time_t
)*state
->TotalBuildTimes
);
611 for (line
= state
->BuildtimeHistogram
; line
; line
= line
->next
) {
612 smartlist_t
*args
= smartlist_create();
613 smartlist_split_string(args
, line
->value
, " ",
614 SPLIT_SKIP_SPACE
|SPLIT_IGNORE_BLANK
, 0);
615 if (smartlist_len(args
) < 2) {
616 *msg
= tor_strdup("Unable to parse circuit build times: "
617 "Too few arguments to CircuitBuildTime");
618 SMARTLIST_FOREACH(args
, char*, cp
, tor_free(cp
));
619 smartlist_free(args
);
622 const char *ms_str
= smartlist_get(args
,0);
623 const char *count_str
= smartlist_get(args
,1);
627 ms
= (build_time_t
)tor_parse_ulong(ms_str
, 0, 0,
628 CBT_BUILD_TIME_MAX
, &ok
, NULL
);
630 *msg
= tor_strdup("Unable to parse circuit build times: "
631 "Unparsable bin number");
632 SMARTLIST_FOREACH(args
, char*, cp
, tor_free(cp
));
633 smartlist_free(args
);
636 count
= (uint32_t)tor_parse_ulong(count_str
, 0, 0,
637 UINT32_MAX
, &ok
, NULL
);
639 *msg
= tor_strdup("Unable to parse circuit build times: "
640 "Unparsable bin count");
641 SMARTLIST_FOREACH(args
, char*, cp
, tor_free(cp
));
642 smartlist_free(args
);
646 if (loaded_cnt
+count
+state
->CircuitBuildAbandonedCount
647 > state
->TotalBuildTimes
) {
649 "Too many build times in state file. "
650 "Stopping short before %d",
652 SMARTLIST_FOREACH(args
, char*, cp
, tor_free(cp
));
653 smartlist_free(args
);
657 for (k
= 0; k
< count
; k
++) {
658 loaded_times
[loaded_cnt
++] = ms
;
661 SMARTLIST_FOREACH(args
, char*, cp
, tor_free(cp
));
662 smartlist_free(args
);
667 "Adding %d timeouts.", state
->CircuitBuildAbandonedCount
);
668 for (i
=0; i
< state
->CircuitBuildAbandonedCount
; i
++) {
669 loaded_times
[loaded_cnt
++] = CBT_BUILD_ABANDONED
;
672 if (loaded_cnt
!= state
->TotalBuildTimes
) {
674 "Corrupt state file? Build times count mismatch. "
675 "Read %d times, but file says %d", loaded_cnt
,
676 state
->TotalBuildTimes
);
677 *msg
= tor_strdup("Build times count mismatch.");
678 circuit_build_times_reset(cbt
);
679 tor_free(loaded_times
);
683 circuit_build_times_shuffle_and_store_array(cbt
, loaded_times
, loaded_cnt
);
685 /* Verify that we didn't overwrite any indexes */
686 for (i
=0; i
< CBT_NCIRCUITS_TO_OBSERVE
; i
++) {
687 if (!cbt
->circuit_build_times
[i
])
692 "Loaded %d/%d values from %d lines in circuit time histogram",
693 tot_values
, cbt
->total_build_times
, N
);
695 if (cbt
->total_build_times
!= tot_values
696 || cbt
->total_build_times
> CBT_NCIRCUITS_TO_OBSERVE
) {
698 "Corrupt state file? Shuffled build times mismatch. "
699 "Read %d times, but file says %d", tot_values
,
700 state
->TotalBuildTimes
);
701 *msg
= tor_strdup("Build times count mismatch.");
702 circuit_build_times_reset(cbt
);
703 tor_free(loaded_times
);
707 circuit_build_times_set_timeout(cbt
);
709 if (!state
->CircuitBuildAbandonedCount
&& cbt
->total_build_times
) {
710 circuit_build_times_filter_timeouts(cbt
);
713 tor_free(loaded_times
);
714 return *msg
? -1 : 0;
718 * Estimates the Xm and Alpha parameters using
719 * http://en.wikipedia.org/wiki/Pareto_distribution#Parameter_estimation
721 * The notable difference is that we use mode instead of min to estimate Xm.
722 * This is because our distribution is frechet-like. We claim this is
723 * an acceptable approximation because we are only concerned with the
724 * accuracy of the CDF of the tail.
727 circuit_build_times_update_alpha(circuit_build_times_t
*cbt
)
729 build_time_t
*x
=cbt
->circuit_build_times
;
731 int n
=0,i
=0,abandoned_count
=0;
732 build_time_t max_time
=0;
734 /* http://en.wikipedia.org/wiki/Pareto_distribution#Parameter_estimation */
735 /* We sort of cheat here and make our samples slightly more pareto-like
736 * and less frechet-like. */
737 cbt
->Xm
= circuit_build_times_get_xm(cbt
);
739 tor_assert(cbt
->Xm
> 0);
741 for (i
=0; i
< CBT_NCIRCUITS_TO_OBSERVE
; i
++) {
746 if (x
[i
] < cbt
->Xm
) {
747 a
+= tor_mathlog(cbt
->Xm
);
748 } else if (x
[i
] == CBT_BUILD_ABANDONED
) {
751 a
+= tor_mathlog(x
[i
]);
759 * We are erring and asserting here because this can only happen
760 * in codepaths other than startup. The startup state parsing code
761 * performs this same check, and resets state if it hits it. If we
762 * hit it at runtime, something serious has gone wrong.
764 if (n
!=cbt
->total_build_times
) {
765 log_err(LD_CIRC
, "Discrepancy in build times count: %d vs %d", n
,
766 cbt
->total_build_times
);
768 tor_assert(n
==cbt
->total_build_times
);
771 /* This can happen if Xm is actually the *maximum* value in the set.
772 * It can also happen if we've abandoned every single circuit somehow.
773 * In either case, tell the caller not to compute a new build timeout. */
775 "Could not determine largest build time (%d). "
776 "Xm is %dms and we've abandoned %d out of %d circuits.", max_time
,
777 cbt
->Xm
, abandoned_count
, n
);
781 a
+= abandoned_count
*tor_mathlog(max_time
);
783 a
-= n
*tor_mathlog(cbt
->Xm
);
784 // Estimator comes from Eq #4 in:
785 // "Bayesian estimation based on trimmed samples from Pareto populations"
786 // by Arturo J. Fernández. We are right-censored only.
787 a
= (n
-abandoned_count
)/a
;
795 * This is the Pareto Quantile Function. It calculates the point x
796 * in the distribution such that F(x) = quantile (ie quantile*100%
797 * of the mass of the density function is below x on the curve).
799 * We use it to calculate the timeout and also to generate synthetic
800 * values of time for circuits that timeout before completion.
802 * See http://en.wikipedia.org/wiki/Quantile_function,
803 * http://en.wikipedia.org/wiki/Inverse_transform_sampling and
804 * http://en.wikipedia.org/wiki/Pareto_distribution#Generating_a_
805 * random_sample_from_Pareto_distribution
806 * That's right. I'll cite wikipedia all day long.
808 * Return value is in milliseconds.
811 circuit_build_times_calculate_timeout(circuit_build_times_t
*cbt
,
815 tor_assert(quantile
>= 0);
816 tor_assert(1.0-quantile
> 0);
817 tor_assert(cbt
->Xm
> 0);
819 ret
= cbt
->Xm
/pow(1.0-quantile
,1.0/cbt
->alpha
);
820 if (ret
> INT32_MAX
) {
829 circuit_build_times_cdf(circuit_build_times_t
*cbt
, double x
)
832 tor_assert(cbt
->Xm
> 0);
833 ret
= 1.0-pow(cbt
->Xm
/x
,cbt
->alpha
);
834 tor_assert(0 <= ret
&& ret
<= 1.0);
839 * Generate a synthetic time using our distribution parameters.
841 * The return value will be within the [q_lo, q_hi) quantile points
845 circuit_build_times_generate_sample(circuit_build_times_t
*cbt
,
846 double q_lo
, double q_hi
)
848 double randval
= crypto_rand_double();
852 /* Generate between [q_lo, q_hi) */
853 /*XXXX This is what nextafter is supposed to be for; we should use it on the
854 * platforms that support it. */
855 q_hi
-= 1.0/(INT32_MAX
);
857 tor_assert(q_lo
>= 0);
858 tor_assert(q_hi
< 1);
859 tor_assert(q_lo
< q_hi
);
861 u
= q_lo
+ (q_hi
-q_lo
)*randval
;
863 tor_assert(0 <= u
&& u
< 1.0);
864 /* circuit_build_times_calculate_timeout returns <= INT32_MAX */
866 tor_lround(circuit_build_times_calculate_timeout(cbt
, u
));
872 * Estimate an initial alpha parameter by solving the quantile
873 * function with a quantile point and a specific timeout value.
876 circuit_build_times_initial_alpha(circuit_build_times_t
*cbt
,
877 double quantile
, double timeout_ms
)
879 // Q(u) = Xm/((1-u)^(1/a))
880 // Q(0.8) = Xm/((1-0.8))^(1/a)) = CircBuildTimeout
881 // CircBuildTimeout = Xm/((1-0.8))^(1/a))
882 // CircBuildTimeout = Xm*((1-0.8))^(-1/a))
883 // ln(CircBuildTimeout) = ln(Xm)+ln(((1-0.8)))*(-1/a)
884 // -ln(1-0.8)/(ln(CircBuildTimeout)-ln(Xm))=a
885 tor_assert(quantile
>= 0);
886 tor_assert(cbt
->Xm
> 0);
887 cbt
->alpha
= tor_mathlog(1.0-quantile
)/
888 (tor_mathlog(cbt
->Xm
)-tor_mathlog(timeout_ms
));
889 tor_assert(cbt
->alpha
> 0);
893 * Returns true if we need circuits to be built
896 circuit_build_times_needs_circuits(circuit_build_times_t
*cbt
)
898 /* Return true if < MIN_CIRCUITS_TO_OBSERVE */
899 if (cbt
->total_build_times
< circuit_build_times_min_circs_to_observe())
905 * Returns true if we should build a timeout test circuit
909 circuit_build_times_needs_circuits_now(circuit_build_times_t
*cbt
)
911 return circuit_build_times_needs_circuits(cbt
) &&
912 approx_time()-cbt
->last_circ_at
> circuit_build_times_test_frequency();
916 * Called to indicate that the network showed some signs of liveness.
918 * This function is called every time we receive a cell. Avoid
919 * syscalls, events, and other high-intensity work.
922 circuit_build_times_network_is_live(circuit_build_times_t
*cbt
)
924 cbt
->liveness
.network_last_live
= approx_time();
925 cbt
->liveness
.nonlive_discarded
= 0;
926 cbt
->liveness
.nonlive_timeouts
= 0;
930 * Called to indicate that we completed a circuit. Because this circuit
931 * succeeded, it doesn't count as a timeout-after-the-first-hop.
934 circuit_build_times_network_circ_success(circuit_build_times_t
*cbt
)
936 cbt
->liveness
.timeouts_after_firsthop
[cbt
->liveness
.after_firsthop_idx
] = 0;
937 cbt
->liveness
.after_firsthop_idx
++;
938 cbt
->liveness
.after_firsthop_idx
%= cbt
->liveness
.num_recent_circs
;
942 * A circuit just timed out. If it failed after the first hop, record it
943 * in our history for later deciding if the network speed has changed.
946 circuit_build_times_network_timeout(circuit_build_times_t
*cbt
,
950 cbt
->liveness
.timeouts_after_firsthop
[cbt
->liveness
.after_firsthop_idx
]=1;
951 cbt
->liveness
.after_firsthop_idx
++;
952 cbt
->liveness
.after_firsthop_idx
%= cbt
->liveness
.num_recent_circs
;
957 * A circuit was just forcibly closed. If there has been no recent network
958 * activity at all, but this circuit was launched back when we thought the
959 * network was live, increment the number of "nonlive" circuit timeouts.
962 circuit_build_times_network_close(circuit_build_times_t
*cbt
,
963 int did_onehop
, time_t start_time
)
965 time_t now
= time(NULL
);
967 * Check if this is a timeout that was for a circuit that spent its
968 * entire existence during a time where we have had no network activity.
970 * Also double check that it is a valid timeout after we have possibly
971 * just recently reset cbt->close_ms.
973 * We use close_ms here because timeouts aren't actually counted as timeouts
974 * until close_ms elapses.
976 if (cbt
->liveness
.network_last_live
<= start_time
&&
977 start_time
<= (now
- cbt
->close_ms
/1000.0)) {
979 char last_live_buf
[ISO_TIME_LEN
+1];
980 char start_time_buf
[ISO_TIME_LEN
+1];
981 char now_buf
[ISO_TIME_LEN
+1];
982 format_local_iso_time(last_live_buf
, cbt
->liveness
.network_last_live
);
983 format_local_iso_time(start_time_buf
, start_time
);
984 format_local_iso_time(now_buf
, now
);
986 "Circuit somehow completed a hop while the network was "
987 "not live. Network was last live at %s, but circuit launched "
988 "at %s. It's now %s.", last_live_buf
, start_time_buf
,
991 cbt
->liveness
.nonlive_timeouts
++;
996 * Returns false if the network has not received a cell or tls handshake
997 * in the past NETWORK_NOTLIVE_TIMEOUT_COUNT circuits.
999 * Also has the side effect of rewinding the circuit time history
1000 * in the case of recent liveness changes.
1003 circuit_build_times_network_check_live(circuit_build_times_t
*cbt
)
1005 time_t now
= approx_time();
1006 if (cbt
->liveness
.nonlive_timeouts
>= CBT_NETWORK_NONLIVE_DISCARD_COUNT
) {
1007 if (!cbt
->liveness
.nonlive_discarded
) {
1008 cbt
->liveness
.nonlive_discarded
= 1;
1009 log_notice(LD_CIRC
, "Network is no longer live (too many recent "
1010 "circuit timeouts). Dead for %ld seconds.",
1011 (long int)(now
- cbt
->liveness
.network_last_live
));
1012 /* Only discard NETWORK_NONLIVE_TIMEOUT_COUNT-1 because we stopped
1013 * counting after that */
1014 circuit_build_times_rewind_history(cbt
,
1015 CBT_NETWORK_NONLIVE_TIMEOUT_COUNT
-1);
1016 control_event_buildtimeout_set(cbt
, BUILDTIMEOUT_SET_EVENT_DISCARD
);
1019 } else if (cbt
->liveness
.nonlive_timeouts
>=
1020 CBT_NETWORK_NONLIVE_TIMEOUT_COUNT
) {
1021 if (cbt
->timeout_ms
< circuit_build_times_get_initial_timeout()) {
1023 "Network is flaky. No activity for %ld seconds. "
1024 "Temporarily raising timeout to %lds.",
1025 (long int)(now
- cbt
->liveness
.network_last_live
),
1026 tor_lround(circuit_build_times_get_initial_timeout()/1000));
1027 cbt
->liveness
.suspended_timeout
= cbt
->timeout_ms
;
1028 cbt
->liveness
.suspended_close_timeout
= cbt
->close_ms
;
1029 cbt
->close_ms
= cbt
->timeout_ms
1030 = circuit_build_times_get_initial_timeout();
1031 control_event_buildtimeout_set(cbt
, BUILDTIMEOUT_SET_EVENT_SUSPENDED
);
1035 } else if (cbt
->liveness
.suspended_timeout
> 0) {
1037 "Network activity has resumed. "
1038 "Resuming circuit timeout calculations.");
1039 cbt
->timeout_ms
= cbt
->liveness
.suspended_timeout
;
1040 cbt
->close_ms
= cbt
->liveness
.suspended_close_timeout
;
1041 cbt
->liveness
.suspended_timeout
= 0;
1042 cbt
->liveness
.suspended_close_timeout
= 0;
1043 control_event_buildtimeout_set(cbt
, BUILDTIMEOUT_SET_EVENT_RESUME
);
1050 * Returns true if we have seen more than MAX_RECENT_TIMEOUT_COUNT of
1051 * the past RECENT_CIRCUITS time out after the first hop. Used to detect
1052 * if the network connection has changed significantly.
1054 * Also resets the entire timeout history in this case and causes us
1055 * to restart the process of building test circuits and estimating a
1059 circuit_build_times_network_check_changed(circuit_build_times_t
*cbt
)
1061 int total_build_times
= cbt
->total_build_times
;
1062 int timeout_count
=0;
1065 /* how many of our recent circuits made it to the first hop but then
1067 for (i
= 0; i
< cbt
->liveness
.num_recent_circs
; i
++) {
1068 timeout_count
+= cbt
->liveness
.timeouts_after_firsthop
[i
];
1071 /* If 80% of our recent circuits are timing out after the first hop,
1072 * we need to re-estimate a new initial alpha and timeout. */
1073 if (timeout_count
< circuit_build_times_max_timeouts()) {
1077 circuit_build_times_reset(cbt
);
1078 memset(cbt
->liveness
.timeouts_after_firsthop
, 0,
1079 sizeof(*cbt
->liveness
.timeouts_after_firsthop
)*
1080 cbt
->liveness
.num_recent_circs
);
1081 cbt
->liveness
.after_firsthop_idx
= 0;
1083 /* Check to see if this has happened before. If so, double the timeout
1084 * to give people on abysmally bad network connections a shot at access */
1085 if (cbt
->timeout_ms
>= circuit_build_times_get_initial_timeout()) {
1086 if (cbt
->timeout_ms
> INT32_MAX
/2 || cbt
->close_ms
> INT32_MAX
/2) {
1087 log_warn(LD_CIRC
, "Insanely large circuit build timeout value. "
1088 "(timeout = %lfmsec, close = %lfmsec)",
1089 cbt
->timeout_ms
, cbt
->close_ms
);
1091 cbt
->timeout_ms
*= 2;
1095 cbt
->close_ms
= cbt
->timeout_ms
1096 = circuit_build_times_get_initial_timeout();
1099 control_event_buildtimeout_set(cbt
, BUILDTIMEOUT_SET_EVENT_RESET
);
1102 "Network connection speed appears to have changed. Resetting "
1103 "timeout to %lds after %d timeouts and %d buildtimes.",
1104 tor_lround(cbt
->timeout_ms
/1000), timeout_count
,
1111 * Count the number of timeouts in a set of cbt data.
1114 circuit_build_times_timeout_rate(const circuit_build_times_t
*cbt
)
1117 for (i
= 0; i
< CBT_NCIRCUITS_TO_OBSERVE
; i
++) {
1118 if (cbt
->circuit_build_times
[i
] >= cbt
->timeout_ms
) {
1123 if (!cbt
->total_build_times
)
1126 return ((double)timeouts
)/cbt
->total_build_times
;
1130 * Count the number of closed circuits in a set of cbt data.
1133 circuit_build_times_close_rate(const circuit_build_times_t
*cbt
)
1136 for (i
= 0; i
< CBT_NCIRCUITS_TO_OBSERVE
; i
++) {
1137 if (cbt
->circuit_build_times
[i
] == CBT_BUILD_ABANDONED
) {
1142 if (!cbt
->total_build_times
)
1145 return ((double)closed
)/cbt
->total_build_times
;
1149 * Store a timeout as a synthetic value.
1151 * Returns true if the store was successful and we should possibly
1152 * update our timeout estimate.
1155 circuit_build_times_count_close(circuit_build_times_t
*cbt
,
1159 if (circuit_build_times_disabled()) {
1160 cbt
->close_ms
= cbt
->timeout_ms
1161 = circuit_build_times_get_initial_timeout();
1165 /* Record this force-close to help determine if the network is dead */
1166 circuit_build_times_network_close(cbt
, did_onehop
, start_time
);
1168 /* Only count timeouts if network is live.. */
1169 if (!circuit_build_times_network_check_live(cbt
)) {
1173 circuit_build_times_add_time(cbt
, CBT_BUILD_ABANDONED
);
1178 * Update timeout counts to determine if we need to expire
1179 * our build time history due to excessive timeouts.
1182 circuit_build_times_count_timeout(circuit_build_times_t
*cbt
,
1185 if (circuit_build_times_disabled()) {
1186 cbt
->close_ms
= cbt
->timeout_ms
1187 = circuit_build_times_get_initial_timeout();
1191 circuit_build_times_network_timeout(cbt
, did_onehop
);
1193 /* If there are a ton of timeouts, we should reset
1194 * the circuit build timeout.
1196 circuit_build_times_network_check_changed(cbt
);
1200 * Estimate a new timeout based on history and set our timeout
1201 * variable accordingly.
1204 circuit_build_times_set_timeout_worker(circuit_build_times_t
*cbt
)
1206 if (cbt
->total_build_times
< circuit_build_times_min_circs_to_observe()) {
1210 if (!circuit_build_times_update_alpha(cbt
))
1213 cbt
->timeout_ms
= circuit_build_times_calculate_timeout(cbt
,
1214 circuit_build_times_quantile_cutoff());
1216 cbt
->close_ms
= circuit_build_times_calculate_timeout(cbt
,
1217 circuit_build_times_close_quantile());
1219 /* Sometimes really fast guard nodes give us such a steep curve
1220 * that this ends up being not that much greater than timeout_ms.
1221 * Make it be at least 1 min to handle this case. */
1222 cbt
->close_ms
= MAX(cbt
->close_ms
, circuit_build_times_initial_timeout());
1224 cbt
->have_computed_timeout
= 1;
1229 * Exposed function to compute a new timeout. Dispatches events and
1230 * also filters out extremely high timeout values.
1233 circuit_build_times_set_timeout(circuit_build_times_t
*cbt
)
1235 long prev_timeout
= tor_lround(cbt
->timeout_ms
/1000);
1236 double timeout_rate
;
1238 if (!circuit_build_times_set_timeout_worker(cbt
))
1241 if (cbt
->timeout_ms
< circuit_build_times_min_timeout()) {
1242 log_warn(LD_CIRC
, "Set buildtimeout to low value %lfms. Setting to %dms",
1243 cbt
->timeout_ms
, circuit_build_times_min_timeout());
1244 cbt
->timeout_ms
= circuit_build_times_min_timeout();
1245 if (cbt
->close_ms
< cbt
->timeout_ms
) {
1246 /* This shouldn't happen because of MAX() in timeout_worker above,
1247 * but doing it just in case */
1248 cbt
->close_ms
= circuit_build_times_initial_timeout();
1252 control_event_buildtimeout_set(cbt
, BUILDTIMEOUT_SET_EVENT_COMPUTED
);
1254 timeout_rate
= circuit_build_times_timeout_rate(cbt
);
1256 if (prev_timeout
> tor_lround(cbt
->timeout_ms
/1000)) {
1258 "Based on %d circuit times, it looks like we don't need to "
1259 "wait so long for circuits to finish. We will now assume a "
1260 "circuit is too slow to use after waiting %ld seconds.",
1261 cbt
->total_build_times
,
1262 tor_lround(cbt
->timeout_ms
/1000));
1264 "Circuit timeout data: %lfms, %lfms, Xm: %d, a: %lf, r: %lf",
1265 cbt
->timeout_ms
, cbt
->close_ms
, cbt
->Xm
, cbt
->alpha
,
1267 } else if (prev_timeout
< tor_lround(cbt
->timeout_ms
/1000)) {
1269 "Based on %d circuit times, it looks like we need to wait "
1270 "longer for circuits to finish. We will now assume a "
1271 "circuit is too slow to use after waiting %ld seconds.",
1272 cbt
->total_build_times
,
1273 tor_lround(cbt
->timeout_ms
/1000));
1275 "Circuit timeout data: %lfms, %lfms, Xm: %d, a: %lf, r: %lf",
1276 cbt
->timeout_ms
, cbt
->close_ms
, cbt
->Xm
, cbt
->alpha
,
1280 "Set circuit build timeout to %lds (%lfms, %lfms, Xm: %d, a: %lf,"
1281 " r: %lf) based on %d circuit times",
1282 tor_lround(cbt
->timeout_ms
/1000),
1283 cbt
->timeout_ms
, cbt
->close_ms
, cbt
->Xm
, cbt
->alpha
, timeout_rate
,
1284 cbt
->total_build_times
);
1288 /** Iterate over values of circ_id, starting from conn-\>next_circ_id,
1289 * and with the high bit specified by conn-\>circ_id_type, until we get
1290 * a circ_id that is not in use by any other circuit on that conn.
1292 * Return it, or 0 if can't get a unique circ_id.
1295 get_unique_circ_id_by_conn(or_connection_t
*conn
)
1297 circid_t test_circ_id
;
1298 circid_t attempts
=0;
1302 if (conn
->circ_id_type
== CIRC_ID_TYPE_NEITHER
) {
1303 log_warn(LD_BUG
, "Trying to pick a circuit ID for a connection from "
1304 "a client with no identity.");
1307 high_bit
= (conn
->circ_id_type
== CIRC_ID_TYPE_HIGHER
) ? 1<<15 : 0;
1309 /* Sequentially iterate over test_circ_id=1...1<<15-1 until we find a
1310 * circID such that (high_bit|test_circ_id) is not already used. */
1311 test_circ_id
= conn
->next_circ_id
++;
1312 if (test_circ_id
== 0 || test_circ_id
>= 1<<15) {
1314 conn
->next_circ_id
= 2;
1316 if (++attempts
> 1<<15) {
1317 /* Make sure we don't loop forever if all circ_id's are used. This
1318 * matters because it's an external DoS opportunity.
1320 log_warn(LD_CIRC
,"No unused circ IDs. Failing.");
1323 test_circ_id
|= high_bit
;
1324 } while (circuit_id_in_use_on_orconn(test_circ_id
, conn
));
1325 return test_circ_id
;
1328 /** If <b>verbose</b> is false, allocate and return a comma-separated list of
1329 * the currently built elements of circuit_t. If <b>verbose</b> is true, also
1330 * list information about link status in a more verbose format using spaces.
1331 * If <b>verbose_names</b> is false, give nicknames for Named routers and hex
1332 * digests for others; if <b>verbose_names</b> is true, use $DIGEST=Name style
1336 circuit_list_path_impl(origin_circuit_t
*circ
, int verbose
, int verbose_names
)
1339 smartlist_t
*elements
;
1340 const char *states
[] = {"closed", "waiting for keys", "open"};
1343 elements
= smartlist_create();
1346 const char *nickname
= build_state_get_exit_nickname(circ
->build_state
);
1348 tor_asprintf(&cp
, "%s%s circ (length %d%s%s):",
1349 circ
->build_state
->is_internal
? "internal" : "exit",
1350 circ
->build_state
->need_uptime
? " (high-uptime)" : "",
1351 circ
->build_state
->desired_path_len
,
1352 circ
->_base
.state
== CIRCUIT_STATE_OPEN
? "" : ", exit ",
1353 circ
->_base
.state
== CIRCUIT_STATE_OPEN
? "" :
1354 (nickname
?nickname
:"*unnamed*"));
1355 smartlist_add(elements
, cp
);
1366 if (!verbose
&& hop
->state
!= CPATH_STATE_OPEN
)
1368 if (!hop
->extend_info
)
1370 id
= hop
->extend_info
->identity_digest
;
1371 if (verbose_names
) {
1372 elt
= tor_malloc(MAX_VERBOSE_NICKNAME_LEN
+1);
1373 if ((ri
= router_get_by_digest(id
))) {
1374 router_get_verbose_nickname(elt
, ri
);
1375 } else if ((rs
= router_get_consensus_status_by_id(id
))) {
1376 routerstatus_get_verbose_nickname(elt
, rs
);
1377 } else if (is_legal_nickname(hop
->extend_info
->nickname
)) {
1379 base16_encode(elt
+1, HEX_DIGEST_LEN
+1, id
, DIGEST_LEN
);
1380 elt
[HEX_DIGEST_LEN
+1]= '~';
1381 strlcpy(elt
+HEX_DIGEST_LEN
+2,
1382 hop
->extend_info
->nickname
, MAX_NICKNAME_LEN
+1);
1385 base16_encode(elt
+1, HEX_DIGEST_LEN
+1, id
, DIGEST_LEN
);
1387 } else { /* ! verbose_names */
1388 if ((ri
= router_get_by_digest(id
)) &&
1390 elt
= tor_strdup(hop
->extend_info
->nickname
);
1392 elt
= tor_malloc(HEX_DIGEST_LEN
+2);
1394 base16_encode(elt
+1, HEX_DIGEST_LEN
+1, id
, DIGEST_LEN
);
1399 size_t len
= strlen(elt
)+2+strlen(states
[hop
->state
])+1;
1400 char *v
= tor_malloc(len
);
1401 tor_assert(hop
->state
<= 2);
1402 tor_snprintf(v
,len
,"%s(%s)",elt
,states
[hop
->state
]);
1403 smartlist_add(elements
, v
);
1406 smartlist_add(elements
, elt
);
1409 } while (hop
!= circ
->cpath
);
1411 s
= smartlist_join_strings(elements
, verbose
?" ":",", 0, NULL
);
1412 SMARTLIST_FOREACH(elements
, char*, cp
, tor_free(cp
));
1413 smartlist_free(elements
);
1417 /** If <b>verbose</b> is false, allocate and return a comma-separated
1418 * list of the currently built elements of circuit_t. If
1419 * <b>verbose</b> is true, also list information about link status in
1420 * a more verbose format using spaces.
1423 circuit_list_path(origin_circuit_t
*circ
, int verbose
)
1425 return circuit_list_path_impl(circ
, verbose
, 0);
1428 /** Allocate and return a comma-separated list of the currently built elements
1429 * of circuit_t, giving each as a verbose nickname.
1432 circuit_list_path_for_controller(origin_circuit_t
*circ
)
1434 return circuit_list_path_impl(circ
, 0, 1);
1437 /** Log, at severity <b>severity</b>, the nicknames of each router in
1438 * circ's cpath. Also log the length of the cpath, and the intended
1442 circuit_log_path(int severity
, unsigned int domain
, origin_circuit_t
*circ
)
1444 char *s
= circuit_list_path(circ
,1);
1445 tor_log(severity
,domain
,"%s",s
);
1449 /** Tell the rep(utation)hist(ory) module about the status of the links
1450 * in circ. Hops that have become OPEN are marked as successfully
1451 * extended; the _first_ hop that isn't open (if any) is marked as
1454 /* XXXX Someday we should learn from OR circuits too. */
1456 circuit_rep_hist_note_result(origin_circuit_t
*circ
)
1459 char *prev_digest
= NULL
;
1460 routerinfo_t
*router
;
1462 if (!hop
) /* circuit hasn't started building yet. */
1464 if (server_mode(get_options())) {
1465 routerinfo_t
*me
= router_get_my_routerinfo();
1468 prev_digest
= me
->cache_info
.identity_digest
;
1471 router
= router_get_by_digest(hop
->extend_info
->identity_digest
);
1474 if (hop
->state
== CPATH_STATE_OPEN
)
1475 rep_hist_note_extend_succeeded(prev_digest
,
1476 router
->cache_info
.identity_digest
);
1478 rep_hist_note_extend_failed(prev_digest
,
1479 router
->cache_info
.identity_digest
);
1483 prev_digest
= router
->cache_info
.identity_digest
;
1488 } while (hop
!=circ
->cpath
);
1491 /** Pick all the entries in our cpath. Stop and return 0 when we're
1492 * happy, or return -1 if an error occurs. */
1494 onion_populate_cpath(origin_circuit_t
*circ
)
1498 r
= onion_extend_cpath(circ
);
1500 log_info(LD_CIRC
,"Generating cpath hop failed.");
1505 return 0; /* if r == 1 */
1508 /** Create and return a new origin circuit. Initialize its purpose and
1509 * build-state based on our arguments. The <b>flags</b> argument is a
1510 * bitfield of CIRCLAUNCH_* flags. */
1512 origin_circuit_init(uint8_t purpose
, int flags
)
1514 /* sets circ->p_circ_id and circ->p_conn */
1515 origin_circuit_t
*circ
= origin_circuit_new();
1516 circuit_set_state(TO_CIRCUIT(circ
), CIRCUIT_STATE_OR_WAIT
);
1517 circ
->build_state
= tor_malloc_zero(sizeof(cpath_build_state_t
));
1518 circ
->build_state
->onehop_tunnel
=
1519 ((flags
& CIRCLAUNCH_ONEHOP_TUNNEL
) ? 1 : 0);
1520 circ
->build_state
->need_uptime
=
1521 ((flags
& CIRCLAUNCH_NEED_UPTIME
) ? 1 : 0);
1522 circ
->build_state
->need_capacity
=
1523 ((flags
& CIRCLAUNCH_NEED_CAPACITY
) ? 1 : 0);
1524 circ
->build_state
->is_internal
=
1525 ((flags
& CIRCLAUNCH_IS_INTERNAL
) ? 1 : 0);
1526 circ
->_base
.purpose
= purpose
;
1530 /** Build a new circuit for <b>purpose</b>. If <b>exit</b>
1531 * is defined, then use that as your exit router, else choose a suitable
1534 * Also launch a connection to the first OR in the chosen path, if
1535 * it's not open already.
1538 circuit_establish_circuit(uint8_t purpose
, extend_info_t
*exit
, int flags
)
1540 origin_circuit_t
*circ
;
1543 circ
= origin_circuit_init(purpose
, flags
);
1545 if (onion_pick_cpath_exit(circ
, exit
) < 0 ||
1546 onion_populate_cpath(circ
) < 0) {
1547 circuit_mark_for_close(TO_CIRCUIT(circ
), END_CIRC_REASON_NOPATH
);
1551 control_event_circuit_status(circ
, CIRC_EVENT_LAUNCHED
, 0);
1553 if ((err_reason
= circuit_handle_first_hop(circ
)) < 0) {
1554 circuit_mark_for_close(TO_CIRCUIT(circ
), -err_reason
);
1560 /** Start establishing the first hop of our circuit. Figure out what
1561 * OR we should connect to, and if necessary start the connection to
1562 * it. If we're already connected, then send the 'create' cell.
1563 * Return 0 for ok, -reason if circ should be marked-for-close. */
1565 circuit_handle_first_hop(origin_circuit_t
*circ
)
1567 crypt_path_t
*firsthop
;
1568 or_connection_t
*n_conn
;
1570 const char *msg
= NULL
;
1571 int should_launch
= 0;
1573 firsthop
= onion_next_hop_in_cpath(circ
->cpath
);
1574 tor_assert(firsthop
);
1575 tor_assert(firsthop
->extend_info
);
1577 /* now see if we're already connected to the first OR in 'route' */
1578 log_debug(LD_CIRC
,"Looking for firsthop '%s:%u'",
1579 fmt_addr(&firsthop
->extend_info
->addr
),
1580 firsthop
->extend_info
->port
);
1582 n_conn
= connection_or_get_for_extend(firsthop
->extend_info
->identity_digest
,
1583 &firsthop
->extend_info
->addr
,
1588 /* not currently connected in a useful way. */
1589 const char *name
= strlen(firsthop
->extend_info
->nickname
) ?
1590 firsthop
->extend_info
->nickname
: fmt_addr(&firsthop
->extend_info
->addr
);
1591 log_info(LD_CIRC
, "Next router is %s: %s ",
1592 safe_str_client(name
), msg
?msg
:"???");
1593 circ
->_base
.n_hop
= extend_info_dup(firsthop
->extend_info
);
1595 if (should_launch
) {
1596 if (circ
->build_state
->onehop_tunnel
)
1597 control_event_bootstrap(BOOTSTRAP_STATUS_CONN_DIR
, 0);
1598 n_conn
= connection_or_connect(&firsthop
->extend_info
->addr
,
1599 firsthop
->extend_info
->port
,
1600 firsthop
->extend_info
->identity_digest
);
1601 if (!n_conn
) { /* connect failed, forget the whole thing */
1602 log_info(LD_CIRC
,"connect to firsthop failed. Closing.");
1603 return -END_CIRC_REASON_CONNECTFAILED
;
1607 log_debug(LD_CIRC
,"connecting in progress (or finished). Good.");
1608 /* return success. The onion/circuit/etc will be taken care of
1609 * automatically (may already have been) whenever n_conn reaches
1610 * OR_CONN_STATE_OPEN.
1613 } else { /* it's already open. use it. */
1614 tor_assert(!circ
->_base
.n_hop
);
1615 circ
->_base
.n_conn
= n_conn
;
1616 log_debug(LD_CIRC
,"Conn open. Delivering first onion skin.");
1617 if ((err_reason
= circuit_send_next_onion_skin(circ
)) < 0) {
1618 log_info(LD_CIRC
,"circuit_send_next_onion_skin failed.");
1625 /** Find any circuits that are waiting on <b>or_conn</b> to become
1626 * open and get them to send their create cells forward.
1628 * Status is 1 if connect succeeded, or 0 if connect failed.
1631 circuit_n_conn_done(or_connection_t
*or_conn
, int status
)
1633 smartlist_t
*pending_circs
;
1636 log_debug(LD_CIRC
,"or_conn to %s/%s, status=%d",
1637 or_conn
->nickname
? or_conn
->nickname
: "NULL",
1638 or_conn
->_base
.address
, status
);
1640 pending_circs
= smartlist_create();
1641 circuit_get_all_pending_on_or_conn(pending_circs
, or_conn
);
1643 SMARTLIST_FOREACH_BEGIN(pending_circs
, circuit_t
*, circ
)
1645 /* These checks are redundant wrt get_all_pending_on_or_conn, but I'm
1646 * leaving them in in case it's possible for the status of a circuit to
1647 * change as we're going down the list. */
1648 if (circ
->marked_for_close
|| circ
->n_conn
|| !circ
->n_hop
||
1649 circ
->state
!= CIRCUIT_STATE_OR_WAIT
)
1652 if (tor_digest_is_zero(circ
->n_hop
->identity_digest
)) {
1653 /* Look at addr/port. This is an unkeyed connection. */
1654 if (!tor_addr_eq(&circ
->n_hop
->addr
, &or_conn
->_base
.addr
) ||
1655 circ
->n_hop
->port
!= or_conn
->_base
.port
)
1658 /* We expected a key. See if it's the right one. */
1659 if (memcmp(or_conn
->identity_digest
,
1660 circ
->n_hop
->identity_digest
, DIGEST_LEN
))
1663 if (!status
) { /* or_conn failed; close circ */
1664 log_info(LD_CIRC
,"or_conn failed. Closing circ.");
1665 circuit_mark_for_close(circ
, END_CIRC_REASON_OR_CONN_CLOSED
);
1668 log_debug(LD_CIRC
, "Found circ, sending create cell.");
1669 /* circuit_deliver_create_cell will set n_circ_id and add us to
1670 * orconn_circuid_circuit_map, so we don't need to call
1671 * set_circid_orconn here. */
1672 circ
->n_conn
= or_conn
;
1673 extend_info_free(circ
->n_hop
);
1676 if (CIRCUIT_IS_ORIGIN(circ
)) {
1678 circuit_send_next_onion_skin(TO_ORIGIN_CIRCUIT(circ
))) < 0) {
1680 "send_next_onion_skin failed; circuit marked for closing.");
1681 circuit_mark_for_close(circ
, -err_reason
);
1683 /* XXX could this be bad, eg if next_onion_skin failed because conn
1687 /* pull the create cell out of circ->onionskin, and send it */
1688 tor_assert(circ
->n_conn_onionskin
);
1689 if (circuit_deliver_create_cell(circ
,CELL_CREATE
,
1690 circ
->n_conn_onionskin
)<0) {
1691 circuit_mark_for_close(circ
, END_CIRC_REASON_RESOURCELIMIT
);
1694 tor_free(circ
->n_conn_onionskin
);
1695 circuit_set_state(circ
, CIRCUIT_STATE_OPEN
);
1698 SMARTLIST_FOREACH_END(circ
);
1700 smartlist_free(pending_circs
);
1703 /** Find a new circid that isn't currently in use on the circ->n_conn
1705 * circuit <b>circ</b>, and deliver a cell of type <b>cell_type</b>
1706 * (either CELL_CREATE or CELL_CREATE_FAST) with payload <b>payload</b>
1708 * Return -1 if we failed to find a suitable circid, else return 0.
1711 circuit_deliver_create_cell(circuit_t
*circ
, uint8_t cell_type
,
1712 const char *payload
)
1718 tor_assert(circ
->n_conn
);
1719 tor_assert(payload
);
1720 tor_assert(cell_type
== CELL_CREATE
|| cell_type
== CELL_CREATE_FAST
);
1722 id
= get_unique_circ_id_by_conn(circ
->n_conn
);
1724 log_warn(LD_CIRC
,"failed to get unique circID.");
1727 log_debug(LD_CIRC
,"Chosen circID %u.", id
);
1728 circuit_set_n_circid_orconn(circ
, id
, circ
->n_conn
);
1730 memset(&cell
, 0, sizeof(cell_t
));
1731 cell
.command
= cell_type
;
1732 cell
.circ_id
= circ
->n_circ_id
;
1734 memcpy(cell
.payload
, payload
, ONIONSKIN_CHALLENGE_LEN
);
1735 append_cell_to_circuit_queue(circ
, circ
->n_conn
, &cell
, CELL_DIRECTION_OUT
);
1737 if (CIRCUIT_IS_ORIGIN(circ
)) {
1738 /* mark it so it gets better rate limiting treatment. */
1739 circ
->n_conn
->client_used
= time(NULL
);
1745 /** We've decided to start our reachability testing. If all
1746 * is set, log this to the user. Return 1 if we did, or 0 if
1747 * we chose not to log anything. */
1749 inform_testing_reachability(void)
1752 routerinfo_t
*me
= router_get_my_routerinfo();
1755 control_event_server_status(LOG_NOTICE
,
1756 "CHECKING_REACHABILITY ORADDRESS=%s:%d",
1757 me
->address
, me
->or_port
);
1759 tor_snprintf(dirbuf
, sizeof(dirbuf
), " and DirPort %s:%d",
1760 me
->address
, me
->dir_port
);
1761 control_event_server_status(LOG_NOTICE
,
1762 "CHECKING_REACHABILITY DIRADDRESS=%s:%d",
1763 me
->address
, me
->dir_port
);
1765 log_notice(LD_OR
, "Now checking whether ORPort %s:%d%s %s reachable... "
1766 "(this may take up to %d minutes -- look for log "
1767 "messages indicating success)",
1768 me
->address
, me
->or_port
,
1769 me
->dir_port
? dirbuf
: "",
1770 me
->dir_port
? "are" : "is",
1771 TIMEOUT_UNTIL_UNREACHABILITY_COMPLAINT
/60);
1776 /** Return true iff we should send a create_fast cell to start building a given
1779 should_use_create_fast_for_circuit(origin_circuit_t
*circ
)
1781 or_options_t
*options
= get_options();
1782 tor_assert(circ
->cpath
);
1783 tor_assert(circ
->cpath
->extend_info
);
1785 if (!circ
->cpath
->extend_info
->onion_key
)
1786 return 1; /* our hand is forced: only a create_fast will work. */
1787 if (!options
->FastFirstHopPK
)
1788 return 0; /* we prefer to avoid create_fast */
1789 if (server_mode(options
)) {
1790 /* We're a server, and we know an onion key. We can choose.
1791 * Prefer to blend in. */
1798 /** This is the backbone function for building circuits.
1800 * If circ's first hop is closed, then we need to build a create
1801 * cell and send it forward.
1803 * Otherwise, we need to build a relay extend cell and send it
1806 * Return -reason if we want to tear down circ, else return 0.
1809 circuit_send_next_onion_skin(origin_circuit_t
*circ
)
1812 routerinfo_t
*router
;
1813 char payload
[2+4+DIGEST_LEN
+ONIONSKIN_CHALLENGE_LEN
];
1819 if (circ
->cpath
->state
== CPATH_STATE_CLOSED
) {
1822 log_debug(LD_CIRC
,"First skin; sending create cell.");
1823 if (circ
->build_state
->onehop_tunnel
)
1824 control_event_bootstrap(BOOTSTRAP_STATUS_ONEHOP_CREATE
, 0);
1826 control_event_bootstrap(BOOTSTRAP_STATUS_CIRCUIT_CREATE
, 0);
1828 router
= router_get_by_digest(circ
->_base
.n_conn
->identity_digest
);
1829 fast
= should_use_create_fast_for_circuit(circ
);
1831 /* We are an OR and we know the right onion key: we should
1832 * send an old slow create cell.
1834 cell_type
= CELL_CREATE
;
1835 if (onion_skin_create(circ
->cpath
->extend_info
->onion_key
,
1836 &(circ
->cpath
->dh_handshake_state
),
1838 log_warn(LD_CIRC
,"onion_skin_create (first hop) failed.");
1839 return - END_CIRC_REASON_INTERNAL
;
1841 note_request("cell: create", 1);
1843 /* We are not an OR, and we're building the first hop of a circuit to a
1844 * new OR: we can be speedy and use CREATE_FAST to save an RSA operation
1845 * and a DH operation. */
1846 cell_type
= CELL_CREATE_FAST
;
1847 memset(payload
, 0, sizeof(payload
));
1848 crypto_rand(circ
->cpath
->fast_handshake_state
,
1849 sizeof(circ
->cpath
->fast_handshake_state
));
1850 memcpy(payload
, circ
->cpath
->fast_handshake_state
,
1851 sizeof(circ
->cpath
->fast_handshake_state
));
1852 note_request("cell: create fast", 1);
1855 if (circuit_deliver_create_cell(TO_CIRCUIT(circ
), cell_type
, payload
) < 0)
1856 return - END_CIRC_REASON_RESOURCELIMIT
;
1858 circ
->cpath
->state
= CPATH_STATE_AWAITING_KEYS
;
1859 circuit_set_state(TO_CIRCUIT(circ
), CIRCUIT_STATE_BUILDING
);
1860 log_info(LD_CIRC
,"First hop: finished sending %s cell to '%s'",
1861 fast
? "CREATE_FAST" : "CREATE",
1862 router
? router
->nickname
: "<unnamed>");
1864 tor_assert(circ
->cpath
->state
== CPATH_STATE_OPEN
);
1865 tor_assert(circ
->_base
.state
== CIRCUIT_STATE_BUILDING
);
1866 log_debug(LD_CIRC
,"starting to send subsequent skin.");
1867 hop
= onion_next_hop_in_cpath(circ
->cpath
);
1869 /* done building the circuit. whew. */
1870 circuit_set_state(TO_CIRCUIT(circ
), CIRCUIT_STATE_OPEN
);
1871 if (!circ
->build_state
->onehop_tunnel
) {
1874 tor_gettimeofday(&end
);
1875 timediff
= tv_mdiff(&circ
->_base
.highres_created
, &end
);
1877 * If the circuit build time is much greater than we would have cut
1878 * it off at, we probably had a suspend event along this codepath,
1879 * and we should discard the value.
1881 if (timediff
< 0 || timediff
> 2*circ_times
.close_ms
+1000) {
1882 log_notice(LD_CIRC
, "Strange value for circuit build time: %ldmsec. "
1883 "Assuming clock jump.", timediff
);
1884 } else if (!circuit_build_times_disabled()) {
1885 /* Don't count circuit times if the network was not live */
1886 if (circuit_build_times_network_check_live(&circ_times
)) {
1887 circuit_build_times_add_time(&circ_times
, (build_time_t
)timediff
);
1888 circuit_build_times_set_timeout(&circ_times
);
1891 if (circ
->_base
.purpose
!= CIRCUIT_PURPOSE_C_MEASURE_TIMEOUT
) {
1892 circuit_build_times_network_circ_success(&circ_times
);
1896 log_info(LD_CIRC
,"circuit built!");
1897 circuit_reset_failure_count(0);
1898 if (circ
->build_state
->onehop_tunnel
)
1899 control_event_bootstrap(BOOTSTRAP_STATUS_REQUESTING_STATUS
, 0);
1900 if (!has_completed_circuit
&& !circ
->build_state
->onehop_tunnel
) {
1901 or_options_t
*options
= get_options();
1902 has_completed_circuit
=1;
1903 /* FFFF Log a count of known routers here */
1904 log_notice(LD_GENERAL
,
1905 "Tor has successfully opened a circuit. "
1906 "Looks like client functionality is working.");
1907 control_event_bootstrap(BOOTSTRAP_STATUS_DONE
, 0);
1908 control_event_client_status(LOG_NOTICE
, "CIRCUIT_ESTABLISHED");
1909 if (server_mode(options
) && !check_whether_orport_reachable()) {
1910 inform_testing_reachability();
1911 consider_testing_reachability(1, 1);
1914 circuit_rep_hist_note_result(circ
);
1915 circuit_has_opened(circ
); /* do other actions as necessary */
1917 /* We're done with measurement circuits here. Just close them */
1918 if (circ
->_base
.purpose
== CIRCUIT_PURPOSE_C_MEASURE_TIMEOUT
)
1919 circuit_mark_for_close(TO_CIRCUIT(circ
), END_CIRC_REASON_FINISHED
);
1923 if (tor_addr_family(&hop
->extend_info
->addr
) != AF_INET
) {
1924 log_warn(LD_BUG
, "Trying to extend to a non-IPv4 address.");
1925 return - END_CIRC_REASON_INTERNAL
;
1928 set_uint32(payload
, tor_addr_to_ipv4n(&hop
->extend_info
->addr
));
1929 set_uint16(payload
+4, htons(hop
->extend_info
->port
));
1931 onionskin
= payload
+2+4;
1932 memcpy(payload
+2+4+ONIONSKIN_CHALLENGE_LEN
,
1933 hop
->extend_info
->identity_digest
, DIGEST_LEN
);
1934 payload_len
= 2+4+ONIONSKIN_CHALLENGE_LEN
+DIGEST_LEN
;
1936 if (onion_skin_create(hop
->extend_info
->onion_key
,
1937 &(hop
->dh_handshake_state
), onionskin
) < 0) {
1938 log_warn(LD_CIRC
,"onion_skin_create failed.");
1939 return - END_CIRC_REASON_INTERNAL
;
1942 log_info(LD_CIRC
,"Sending extend relay cell.");
1943 note_request("cell: extend", 1);
1944 /* send it to hop->prev, because it will transfer
1945 * it to a create cell and then send to hop */
1946 if (relay_send_command_from_edge(0, TO_CIRCUIT(circ
),
1947 RELAY_COMMAND_EXTEND
,
1948 payload
, payload_len
, hop
->prev
) < 0)
1949 return 0; /* circuit is closed */
1951 hop
->state
= CPATH_STATE_AWAITING_KEYS
;
1956 /** Our clock just jumped by <b>seconds_elapsed</b>. Assume
1957 * something has also gone wrong with our network: notify the user,
1958 * and abandon all not-yet-used circuits. */
1960 circuit_note_clock_jumped(int seconds_elapsed
)
1962 int severity
= server_mode(get_options()) ? LOG_WARN
: LOG_NOTICE
;
1963 tor_log(severity
, LD_GENERAL
, "Your system clock just jumped %d seconds %s; "
1964 "assuming established circuits no longer work.",
1965 seconds_elapsed
>=0 ? seconds_elapsed
: -seconds_elapsed
,
1966 seconds_elapsed
>=0 ? "forward" : "backward");
1967 control_event_general_status(LOG_WARN
, "CLOCK_JUMPED TIME=%d",
1969 has_completed_circuit
=0; /* so it'll log when it works again */
1970 control_event_client_status(severity
, "CIRCUIT_NOT_ESTABLISHED REASON=%s",
1972 circuit_mark_all_unused_circs();
1973 circuit_expire_all_dirty_circs();
1976 /** Take the 'extend' <b>cell</b>, pull out addr/port plus the onion
1977 * skin and identity digest for the next hop. If we're already connected,
1978 * pass the onion skin to the next hop using a create cell; otherwise
1979 * launch a new OR connection, and <b>circ</b> will notice when the
1980 * connection succeeds or fails.
1982 * Return -1 if we want to warn and tear down the circuit, else return 0.
1985 circuit_extend(cell_t
*cell
, circuit_t
*circ
)
1987 or_connection_t
*n_conn
;
1990 char *id_digest
=NULL
;
1994 const char *msg
= NULL
;
1995 int should_launch
= 0;
1998 log_fn(LOG_PROTOCOL_WARN
, LD_PROTOCOL
,
1999 "n_conn already set. Bug/attack. Closing.");
2003 log_fn(LOG_PROTOCOL_WARN
, LD_PROTOCOL
,
2004 "conn to next hop already launched. Bug/attack. Closing.");
2008 if (!server_mode(get_options())) {
2009 log_fn(LOG_PROTOCOL_WARN
, LD_PROTOCOL
,
2010 "Got an extend cell, but running as a client. Closing.");
2014 relay_header_unpack(&rh
, cell
->payload
);
2016 if (rh
.length
< 4+2+ONIONSKIN_CHALLENGE_LEN
+DIGEST_LEN
) {
2017 log_fn(LOG_PROTOCOL_WARN
, LD_PROTOCOL
,
2018 "Wrong length %d on extend cell. Closing circuit.",
2023 n_addr32
= ntohl(get_uint32(cell
->payload
+RELAY_HEADER_SIZE
));
2024 n_port
= ntohs(get_uint16(cell
->payload
+RELAY_HEADER_SIZE
+4));
2025 onionskin
= cell
->payload
+RELAY_HEADER_SIZE
+4+2;
2026 id_digest
= cell
->payload
+RELAY_HEADER_SIZE
+4+2+ONIONSKIN_CHALLENGE_LEN
;
2027 tor_addr_from_ipv4h(&n_addr
, n_addr32
);
2029 if (!n_port
|| !n_addr32
) {
2030 log_fn(LOG_PROTOCOL_WARN
, LD_PROTOCOL
,
2031 "Client asked me to extend to zero destination port or addr.");
2035 /* Check if they asked us for 0000..0000. We support using
2036 * an empty fingerprint for the first hop (e.g. for a bridge relay),
2037 * but we don't want to let people send us extend cells for empty
2038 * fingerprints -- a) because it opens the user up to a mitm attack,
2039 * and b) because it lets an attacker force the relay to hold open a
2040 * new TLS connection for each extend request. */
2041 if (tor_digest_is_zero(id_digest
)) {
2042 log_fn(LOG_PROTOCOL_WARN
, LD_PROTOCOL
,
2043 "Client asked me to extend without specifying an id_digest.");
2047 /* Next, check if we're being asked to connect to the hop that the
2048 * extend cell came from. There isn't any reason for that, and it can
2049 * assist circular-path attacks. */
2050 if (!memcmp(id_digest
, TO_OR_CIRCUIT(circ
)->p_conn
->identity_digest
,
2052 log_fn(LOG_PROTOCOL_WARN
, LD_PROTOCOL
,
2053 "Client asked me to extend back to the previous hop.");
2057 n_conn
= connection_or_get_for_extend(id_digest
,
2063 log_debug(LD_CIRC
|LD_OR
,"Next router (%s:%d): %s",
2064 fmt_addr(&n_addr
), (int)n_port
, msg
?msg
:"????");
2066 circ
->n_hop
= extend_info_alloc(NULL
/*nickname*/,
2071 circ
->n_conn_onionskin
= tor_malloc(ONIONSKIN_CHALLENGE_LEN
);
2072 memcpy(circ
->n_conn_onionskin
, onionskin
, ONIONSKIN_CHALLENGE_LEN
);
2073 circuit_set_state(circ
, CIRCUIT_STATE_OR_WAIT
);
2075 if (should_launch
) {
2076 /* we should try to open a connection */
2077 n_conn
= connection_or_connect(&n_addr
, n_port
, id_digest
);
2079 log_info(LD_CIRC
,"Launching n_conn failed. Closing circuit.");
2080 circuit_mark_for_close(circ
, END_CIRC_REASON_CONNECTFAILED
);
2083 log_debug(LD_CIRC
,"connecting in progress (or finished). Good.");
2085 /* return success. The onion/circuit/etc will be taken care of
2086 * automatically (may already have been) whenever n_conn reaches
2087 * OR_CONN_STATE_OPEN.
2092 tor_assert(!circ
->n_hop
); /* Connection is already established. */
2093 circ
->n_conn
= n_conn
;
2094 log_debug(LD_CIRC
,"n_conn is %s:%u",
2095 n_conn
->_base
.address
,n_conn
->_base
.port
);
2097 if (circuit_deliver_create_cell(circ
, CELL_CREATE
, onionskin
) < 0)
2102 /** Initialize cpath-\>{f|b}_{crypto|digest} from the key material in
2103 * key_data. key_data must contain CPATH_KEY_MATERIAL bytes, which are
2105 * - 20 to initialize f_digest
2106 * - 20 to initialize b_digest
2107 * - 16 to key f_crypto
2108 * - 16 to key b_crypto
2110 * (If 'reverse' is true, then f_XX and b_XX are swapped.)
2113 circuit_init_cpath_crypto(crypt_path_t
*cpath
, const char *key_data
,
2116 crypto_digest_env_t
*tmp_digest
;
2117 crypto_cipher_env_t
*tmp_crypto
;
2120 tor_assert(key_data
);
2121 tor_assert(!(cpath
->f_crypto
|| cpath
->b_crypto
||
2122 cpath
->f_digest
|| cpath
->b_digest
));
2124 cpath
->f_digest
= crypto_new_digest_env();
2125 crypto_digest_add_bytes(cpath
->f_digest
, key_data
, DIGEST_LEN
);
2126 cpath
->b_digest
= crypto_new_digest_env();
2127 crypto_digest_add_bytes(cpath
->b_digest
, key_data
+DIGEST_LEN
, DIGEST_LEN
);
2129 if (!(cpath
->f_crypto
=
2130 crypto_create_init_cipher(key_data
+(2*DIGEST_LEN
),1))) {
2131 log_warn(LD_BUG
,"Forward cipher initialization failed.");
2134 if (!(cpath
->b_crypto
=
2135 crypto_create_init_cipher(key_data
+(2*DIGEST_LEN
)+CIPHER_KEY_LEN
,0))) {
2136 log_warn(LD_BUG
,"Backward cipher initialization failed.");
2141 tmp_digest
= cpath
->f_digest
;
2142 cpath
->f_digest
= cpath
->b_digest
;
2143 cpath
->b_digest
= tmp_digest
;
2144 tmp_crypto
= cpath
->f_crypto
;
2145 cpath
->f_crypto
= cpath
->b_crypto
;
2146 cpath
->b_crypto
= tmp_crypto
;
2152 /** A created or extended cell came back to us on the circuit, and it included
2153 * <b>reply</b> as its body. (If <b>reply_type</b> is CELL_CREATED, the body
2154 * contains (the second DH key, plus KH). If <b>reply_type</b> is
2155 * CELL_CREATED_FAST, the body contains a secret y and a hash H(x|y).)
2157 * Calculate the appropriate keys and digests, make sure KH is
2158 * correct, and initialize this hop of the cpath.
2160 * Return - reason if we want to mark circ for close, else return 0.
2163 circuit_finish_handshake(origin_circuit_t
*circ
, uint8_t reply_type
,
2166 char keys
[CPATH_KEY_MATERIAL_LEN
];
2169 if (circ
->cpath
->state
== CPATH_STATE_AWAITING_KEYS
)
2172 hop
= onion_next_hop_in_cpath(circ
->cpath
);
2173 if (!hop
) { /* got an extended when we're all done? */
2174 log_warn(LD_PROTOCOL
,"got extended when circ already built? Closing.");
2175 return - END_CIRC_REASON_TORPROTOCOL
;
2178 tor_assert(hop
->state
== CPATH_STATE_AWAITING_KEYS
);
2180 if (reply_type
== CELL_CREATED
&& hop
->dh_handshake_state
) {
2181 if (onion_skin_client_handshake(hop
->dh_handshake_state
, reply
, keys
,
2182 DIGEST_LEN
*2+CIPHER_KEY_LEN
*2) < 0) {
2183 log_warn(LD_CIRC
,"onion_skin_client_handshake failed.");
2184 return -END_CIRC_REASON_TORPROTOCOL
;
2186 /* Remember hash of g^xy */
2187 memcpy(hop
->handshake_digest
, reply
+DH_KEY_LEN
, DIGEST_LEN
);
2188 } else if (reply_type
== CELL_CREATED_FAST
&& !hop
->dh_handshake_state
) {
2189 if (fast_client_handshake(hop
->fast_handshake_state
, reply
, keys
,
2190 DIGEST_LEN
*2+CIPHER_KEY_LEN
*2) < 0) {
2191 log_warn(LD_CIRC
,"fast_client_handshake failed.");
2192 return -END_CIRC_REASON_TORPROTOCOL
;
2194 memcpy(hop
->handshake_digest
, reply
+DIGEST_LEN
, DIGEST_LEN
);
2196 log_warn(LD_PROTOCOL
,"CREATED cell type did not match CREATE cell type.");
2197 return -END_CIRC_REASON_TORPROTOCOL
;
2200 crypto_dh_free(hop
->dh_handshake_state
); /* don't need it anymore */
2201 hop
->dh_handshake_state
= NULL
;
2203 memset(hop
->fast_handshake_state
, 0, sizeof(hop
->fast_handshake_state
));
2205 if (circuit_init_cpath_crypto(hop
, keys
, 0)<0) {
2206 return -END_CIRC_REASON_TORPROTOCOL
;
2209 hop
->state
= CPATH_STATE_OPEN
;
2210 log_info(LD_CIRC
,"Finished building %scircuit hop:",
2211 (reply_type
== CELL_CREATED_FAST
) ? "fast " : "");
2212 circuit_log_path(LOG_INFO
,LD_CIRC
,circ
);
2213 control_event_circuit_status(circ
, CIRC_EVENT_EXTENDED
, 0);
2218 /** We received a relay truncated cell on circ.
2220 * Since we don't ask for truncates currently, getting a truncated
2221 * means that a connection broke or an extend failed. For now,
2222 * just give up: for circ to close, and return 0.
2225 circuit_truncated(origin_circuit_t
*circ
, crypt_path_t
*layer
)
2227 // crypt_path_t *victim;
2228 // connection_t *stream;
2233 /* XXX Since we don't ask for truncates currently, getting a truncated
2234 * means that a connection broke or an extend failed. For now,
2237 circuit_mark_for_close(TO_CIRCUIT(circ
),
2238 END_CIRC_REASON_FLAG_REMOTE
|END_CIRC_REASON_OR_CONN_CLOSED
);
2242 while (layer
->next
!= circ
->cpath
) {
2243 /* we need to clear out layer->next */
2244 victim
= layer
->next
;
2245 log_debug(LD_CIRC
, "Killing a layer of the cpath.");
2247 for (stream
= circ
->p_streams
; stream
; stream
=stream
->next_stream
) {
2248 if (stream
->cpath_layer
== victim
) {
2249 log_info(LD_APP
, "Marking stream %d for close because of truncate.",
2251 /* no need to send 'end' relay cells,
2252 * because the other side's already dead
2254 connection_mark_unattached_ap(stream
, END_STREAM_REASON_DESTROY
);
2258 layer
->next
= victim
->next
;
2259 circuit_free_cpath_node(victim
);
2262 log_info(LD_CIRC
, "finished");
2267 /** Given a response payload and keys, initialize, then send a created
2271 onionskin_answer(or_circuit_t
*circ
, uint8_t cell_type
, const char *payload
,
2275 crypt_path_t
*tmp_cpath
;
2277 tmp_cpath
= tor_malloc_zero(sizeof(crypt_path_t
));
2278 tmp_cpath
->magic
= CRYPT_PATH_MAGIC
;
2280 memset(&cell
, 0, sizeof(cell_t
));
2281 cell
.command
= cell_type
;
2282 cell
.circ_id
= circ
->p_circ_id
;
2284 circuit_set_state(TO_CIRCUIT(circ
), CIRCUIT_STATE_OPEN
);
2286 memcpy(cell
.payload
, payload
,
2287 cell_type
== CELL_CREATED
? ONIONSKIN_REPLY_LEN
: DIGEST_LEN
*2);
2289 log_debug(LD_CIRC
,"init digest forward 0x%.8x, backward 0x%.8x.",
2290 (unsigned int)*(uint32_t*)(keys
),
2291 (unsigned int)*(uint32_t*)(keys
+20));
2292 if (circuit_init_cpath_crypto(tmp_cpath
, keys
, 0)<0) {
2293 log_warn(LD_BUG
,"Circuit initialization failed");
2294 tor_free(tmp_cpath
);
2297 circ
->n_digest
= tmp_cpath
->f_digest
;
2298 circ
->n_crypto
= tmp_cpath
->f_crypto
;
2299 circ
->p_digest
= tmp_cpath
->b_digest
;
2300 circ
->p_crypto
= tmp_cpath
->b_crypto
;
2301 tmp_cpath
->magic
= 0;
2302 tor_free(tmp_cpath
);
2304 if (cell_type
== CELL_CREATED
)
2305 memcpy(circ
->handshake_digest
, cell
.payload
+DH_KEY_LEN
, DIGEST_LEN
);
2307 memcpy(circ
->handshake_digest
, cell
.payload
+DIGEST_LEN
, DIGEST_LEN
);
2309 circ
->is_first_hop
= (cell_type
== CELL_CREATED_FAST
);
2311 append_cell_to_circuit_queue(TO_CIRCUIT(circ
),
2312 circ
->p_conn
, &cell
, CELL_DIRECTION_IN
);
2313 log_debug(LD_CIRC
,"Finished sending 'created' cell.");
2315 if (!is_local_addr(&circ
->p_conn
->_base
.addr
) &&
2316 !connection_or_nonopen_was_started_here(circ
->p_conn
)) {
2317 /* record that we could process create cells from a non-local conn
2318 * that we didn't initiate; presumably this means that create cells
2319 * can reach us too. */
2320 router_orport_found_reachable();
2326 /** How many hops does a general-purpose circuit have by default? */
2327 #define DEFAULT_ROUTE_LEN 3
2329 /** Choose a length for a circuit of purpose <b>purpose</b>.
2330 * Default length is 3 + the number of endpoints that would give something
2331 * away. If the routerlist <b>routers</b> doesn't have enough routers
2332 * to handle the desired path length, return as large a path length as
2333 * is feasible, except if it's less than 2, in which case return -1.
2336 new_route_len(uint8_t purpose
, extend_info_t
*exit
,
2337 smartlist_t
*routers
)
2339 int num_acceptable_routers
;
2342 tor_assert(routers
);
2344 routelen
= DEFAULT_ROUTE_LEN
;
2346 purpose
!= CIRCUIT_PURPOSE_TESTING
&&
2347 purpose
!= CIRCUIT_PURPOSE_S_ESTABLISH_INTRO
)
2350 num_acceptable_routers
= count_acceptable_routers(routers
);
2352 log_debug(LD_CIRC
,"Chosen route length %d (%d/%d routers suitable).",
2353 routelen
, num_acceptable_routers
, smartlist_len(routers
));
2355 if (num_acceptable_routers
< 2) {
2357 "Not enough acceptable routers (%d). Discarding this circuit.",
2358 num_acceptable_routers
);
2362 if (num_acceptable_routers
< routelen
) {
2363 log_info(LD_CIRC
,"Not enough routers: cutting routelen from %d to %d.",
2364 routelen
, num_acceptable_routers
);
2365 routelen
= num_acceptable_routers
;
2371 /** Fetch the list of predicted ports, dup it into a smartlist of
2372 * uint16_t's, remove the ones that are already handled by an
2373 * existing circuit, and return it.
2375 static smartlist_t
*
2376 circuit_get_unhandled_ports(time_t now
)
2378 smartlist_t
*source
= rep_hist_get_predicted_ports(now
);
2379 smartlist_t
*dest
= smartlist_create();
2383 for (i
= 0; i
< smartlist_len(source
); ++i
) {
2384 tmp
= tor_malloc(sizeof(uint16_t));
2385 memcpy(tmp
, smartlist_get(source
, i
), sizeof(uint16_t));
2386 smartlist_add(dest
, tmp
);
2389 circuit_remove_handled_ports(dest
);
2393 /** Return 1 if we already have circuits present or on the way for
2394 * all anticipated ports. Return 0 if we should make more.
2396 * If we're returning 0, set need_uptime and need_capacity to
2397 * indicate any requirements that the unhandled ports have.
2400 circuit_all_predicted_ports_handled(time_t now
, int *need_uptime
,
2405 smartlist_t
*sl
= circuit_get_unhandled_ports(now
);
2406 smartlist_t
*LongLivedServices
= get_options()->LongLivedPorts
;
2407 tor_assert(need_uptime
);
2408 tor_assert(need_capacity
);
2409 // Always predict need_capacity
2411 enough
= (smartlist_len(sl
) == 0);
2412 for (i
= 0; i
< smartlist_len(sl
); ++i
) {
2413 port
= smartlist_get(sl
, i
);
2414 if (smartlist_string_num_isin(LongLivedServices
, *port
))
2422 /** Return 1 if <b>router</b> can handle one or more of the ports in
2423 * <b>needed_ports</b>, else return 0.
2426 router_handles_some_port(routerinfo_t
*router
, smartlist_t
*needed_ports
)
2431 for (i
= 0; i
< smartlist_len(needed_ports
); ++i
) {
2432 addr_policy_result_t r
;
2433 port
= *(uint16_t *)smartlist_get(needed_ports
, i
);
2435 r
= compare_addr_to_addr_policy(0, port
, router
->exit_policy
);
2436 if (r
!= ADDR_POLICY_REJECTED
&& r
!= ADDR_POLICY_PROBABLY_REJECTED
)
2442 /** Return true iff <b>conn</b> needs another general circuit to be
2445 ap_stream_wants_exit_attention(connection_t
*conn
)
2447 if (conn
->type
== CONN_TYPE_AP
&&
2448 conn
->state
== AP_CONN_STATE_CIRCUIT_WAIT
&&
2449 !conn
->marked_for_close
&&
2450 !(TO_EDGE_CONN(conn
)->want_onehop
) && /* ignore one-hop streams */
2451 !(TO_EDGE_CONN(conn
)->use_begindir
) && /* ignore targeted dir fetches */
2452 !(TO_EDGE_CONN(conn
)->chosen_exit_name
) && /* ignore defined streams */
2453 !connection_edge_is_rendezvous_stream(TO_EDGE_CONN(conn
)) &&
2454 !circuit_stream_is_being_handled(TO_EDGE_CONN(conn
), 0,
2455 MIN_CIRCUITS_HANDLING_STREAM
))
2460 /** Return a pointer to a suitable router to be the exit node for the
2461 * general-purpose circuit we're about to build.
2463 * Look through the connection array, and choose a router that maximizes
2464 * the number of pending streams that can exit from this router.
2466 * Return NULL if we can't find any suitable routers.
2468 static routerinfo_t
*
2469 choose_good_exit_server_general(routerlist_t
*dir
, int need_uptime
,
2474 int n_pending_connections
= 0;
2475 smartlist_t
*connections
;
2476 int best_support
= -1;
2477 int n_best_support
=0;
2478 routerinfo_t
*router
;
2479 or_options_t
*options
= get_options();
2481 connections
= get_connection_array();
2483 /* Count how many connections are waiting for a circuit to be built.
2484 * We use this for log messages now, but in the future we may depend on it.
2486 SMARTLIST_FOREACH(connections
, connection_t
*, conn
,
2488 if (ap_stream_wants_exit_attention(conn
))
2489 ++n_pending_connections
;
2491 // log_fn(LOG_DEBUG, "Choosing exit node; %d connections are pending",
2492 // n_pending_connections);
2493 /* Now we count, for each of the routers in the directory, how many
2494 * of the pending connections could possibly exit from that
2495 * router (n_supported[i]). (We can't be sure about cases where we
2496 * don't know the IP address of the pending connection.)
2498 * -1 means "Don't use this router at all."
2500 n_supported
= tor_malloc(sizeof(int)*smartlist_len(dir
->routers
));
2501 for (i
= 0; i
< smartlist_len(dir
->routers
); ++i
) {/* iterate over routers */
2502 router
= smartlist_get(dir
->routers
, i
);
2503 if (router_is_me(router
)) {
2504 n_supported
[i
] = -1;
2505 // log_fn(LOG_DEBUG,"Skipping node %s -- it's me.", router->nickname);
2506 /* XXX there's probably a reverse predecessor attack here, but
2507 * it's slow. should we take this out? -RD
2511 if (!router
->is_running
|| router
->is_bad_exit
) {
2512 n_supported
[i
] = -1;
2513 continue; /* skip routers that are known to be down or bad exits */
2515 if (router_is_unreliable(router
, need_uptime
, need_capacity
, 0) &&
2516 (!options
->ExitNodes
||
2517 !routerset_contains_router(options
->ExitNodes
, router
))) {
2518 /* FFFF Someday, differentiate between a routerset that names
2519 * routers, and a routerset that names countries, and only do this
2520 * check if they've asked for specific exit relays. Or if the country
2521 * they ask for is rare. Or something. */
2522 n_supported
[i
] = -1;
2523 continue; /* skip routers that are not suitable, unless we have
2524 * ExitNodes set, in which case we asked for it */
2526 if (!(router
->is_valid
|| options
->_AllowInvalid
& ALLOW_INVALID_EXIT
)) {
2527 /* if it's invalid and we don't want it */
2528 n_supported
[i
] = -1;
2529 // log_fn(LOG_DEBUG,"Skipping node %s (index %d) -- invalid router.",
2530 // router->nickname, i);
2531 continue; /* skip invalid routers */
2533 if (options
->ExcludeSingleHopRelays
&& router
->allow_single_hop_exits
) {
2534 n_supported
[i
] = -1;
2537 if (router_exit_policy_rejects_all(router
)) {
2538 n_supported
[i
] = -1;
2539 // log_fn(LOG_DEBUG,"Skipping node %s (index %d) -- it rejects all.",
2540 // router->nickname, i);
2541 continue; /* skip routers that reject all */
2544 /* iterate over connections */
2545 SMARTLIST_FOREACH(connections
, connection_t
*, conn
,
2547 if (!ap_stream_wants_exit_attention(conn
))
2548 continue; /* Skip everything but APs in CIRCUIT_WAIT */
2549 if (connection_ap_can_use_exit(TO_EDGE_CONN(conn
), router
, 1)) {
2551 // log_fn(LOG_DEBUG,"%s is supported. n_supported[%d] now %d.",
2552 // router->nickname, i, n_supported[i]);
2554 // log_fn(LOG_DEBUG,"%s (index %d) would reject this stream.",
2555 // router->nickname, i);
2557 }); /* End looping over connections. */
2558 if (n_pending_connections
> 0 && n_supported
[i
] == 0) {
2559 /* Leave best_support at -1 if that's where it is, so we can
2560 * distinguish it later. */
2563 if (n_supported
[i
] > best_support
) {
2564 /* If this router is better than previous ones, remember its index
2565 * and goodness, and start counting how many routers are this good. */
2566 best_support
= n_supported
[i
]; n_best_support
=1;
2567 // log_fn(LOG_DEBUG,"%s is new best supported option so far.",
2568 // router->nickname);
2569 } else if (n_supported
[i
] == best_support
) {
2570 /* If this router is _as good_ as the best one, just increment the
2571 * count of equally good routers.*/
2576 "Found %d servers that might support %d/%d pending connections.",
2577 n_best_support
, best_support
>= 0 ? best_support
: 0,
2578 n_pending_connections
);
2580 /* If any routers definitely support any pending connections, choose one
2582 if (best_support
> 0) {
2583 smartlist_t
*supporting
= smartlist_create(), *use
= smartlist_create();
2585 for (i
= 0; i
< smartlist_len(dir
->routers
); i
++)
2586 if (n_supported
[i
] == best_support
)
2587 smartlist_add(supporting
, smartlist_get(dir
->routers
, i
));
2589 routersets_get_disjunction(use
, supporting
, options
->ExitNodes
,
2590 options
->_ExcludeExitNodesUnion
, 1);
2591 if (smartlist_len(use
) == 0 && options
->ExitNodes
&&
2592 !options
->StrictNodes
) { /* give up on exitnodes and try again */
2593 routersets_get_disjunction(use
, supporting
, NULL
,
2594 options
->_ExcludeExitNodesUnion
, 1);
2596 router
= routerlist_sl_choose_by_bandwidth(use
, WEIGHT_FOR_EXIT
);
2597 smartlist_free(use
);
2598 smartlist_free(supporting
);
2600 /* Either there are no pending connections, or no routers even seem to
2601 * possibly support any of them. Choose a router at random that satisfies
2602 * at least one predicted exit port. */
2605 smartlist_t
*needed_ports
, *supporting
, *use
;
2607 if (best_support
== -1) {
2608 if (need_uptime
|| need_capacity
) {
2610 "We couldn't find any live%s%s routers; falling back "
2611 "to list of all routers.",
2612 need_capacity
?", fast":"",
2613 need_uptime
?", stable":"");
2614 tor_free(n_supported
);
2615 return choose_good_exit_server_general(dir
, 0, 0);
2617 log_notice(LD_CIRC
, "All routers are down or won't exit%s -- "
2618 "choosing a doomed exit at random.",
2619 options
->_ExcludeExitNodesUnion
? " or are Excluded" : "");
2621 supporting
= smartlist_create();
2622 use
= smartlist_create();
2623 needed_ports
= circuit_get_unhandled_ports(time(NULL
));
2624 for (attempt
= 0; attempt
< 2; attempt
++) {
2625 /* try once to pick only from routers that satisfy a needed port,
2626 * then if there are none, pick from any that support exiting. */
2627 for (i
= 0; i
< smartlist_len(dir
->routers
); i
++) {
2628 router
= smartlist_get(dir
->routers
, i
);
2629 if (n_supported
[i
] != -1 &&
2630 (attempt
|| router_handles_some_port(router
, needed_ports
))) {
2631 // log_fn(LOG_DEBUG,"Try %d: '%s' is a possibility.",
2632 // try, router->nickname);
2633 smartlist_add(supporting
, router
);
2637 routersets_get_disjunction(use
, supporting
, options
->ExitNodes
,
2638 options
->_ExcludeExitNodesUnion
, 1);
2639 if (smartlist_len(use
) == 0 && options
->ExitNodes
&&
2640 !options
->StrictNodes
) { /* give up on exitnodes and try again */
2641 routersets_get_disjunction(use
, supporting
, NULL
,
2642 options
->_ExcludeExitNodesUnion
, 1);
2644 /* FFF sometimes the above results in null, when the requested
2645 * exit node is considered down by the consensus. we should pick
2646 * it anyway, since the user asked for it. */
2647 router
= routerlist_sl_choose_by_bandwidth(use
, WEIGHT_FOR_EXIT
);
2650 smartlist_clear(supporting
);
2651 smartlist_clear(use
);
2653 SMARTLIST_FOREACH(needed_ports
, uint16_t *, cp
, tor_free(cp
));
2654 smartlist_free(needed_ports
);
2655 smartlist_free(use
);
2656 smartlist_free(supporting
);
2659 tor_free(n_supported
);
2661 log_info(LD_CIRC
, "Chose exit server '%s'", router
->nickname
);
2664 if (options
->ExitNodes
&& options
->StrictNodes
) {
2666 "No specified exit routers seem to be running, and "
2667 "StrictNodes is set: can't choose an exit.");
2672 /** Return a pointer to a suitable router to be the exit node for the
2673 * circuit of purpose <b>purpose</b> that we're about to build (or NULL
2674 * if no router is suitable).
2676 * For general-purpose circuits, pass it off to
2677 * choose_good_exit_server_general()
2679 * For client-side rendezvous circuits, choose a random node, weighted
2680 * toward the preferences in 'options'.
2682 static routerinfo_t
*
2683 choose_good_exit_server(uint8_t purpose
, routerlist_t
*dir
,
2684 int need_uptime
, int need_capacity
, int is_internal
)
2686 or_options_t
*options
= get_options();
2687 router_crn_flags_t flags
= 0;
2689 flags
|= CRN_NEED_UPTIME
;
2691 flags
|= CRN_NEED_CAPACITY
;
2694 case CIRCUIT_PURPOSE_C_GENERAL
:
2695 if (options
->_AllowInvalid
& ALLOW_INVALID_MIDDLE
)
2696 flags
|= CRN_ALLOW_INVALID
;
2697 if (is_internal
) /* pick it like a middle hop */
2698 return router_choose_random_node(NULL
, options
->ExcludeNodes
, flags
);
2700 return choose_good_exit_server_general(dir
,need_uptime
,need_capacity
);
2701 case CIRCUIT_PURPOSE_C_ESTABLISH_REND
:
2702 if (options
->_AllowInvalid
& ALLOW_INVALID_RENDEZVOUS
)
2703 flags
|= CRN_ALLOW_INVALID
;
2704 return router_choose_random_node(NULL
, options
->ExcludeNodes
, flags
);
2706 log_warn(LD_BUG
,"Unhandled purpose %d", purpose
);
2707 tor_fragile_assert();
2711 /** Log a warning if the user specified an exit for the circuit that
2712 * has been excluded from use by ExcludeNodes or ExcludeExitNodes. */
2714 warn_if_last_router_excluded(origin_circuit_t
*circ
, const extend_info_t
*exit
)
2716 or_options_t
*options
= get_options();
2717 routerset_t
*rs
= options
->ExcludeNodes
;
2718 const char *description
;
2719 int domain
= LD_CIRC
;
2720 uint8_t purpose
= circ
->_base
.purpose
;
2722 if (circ
->build_state
->onehop_tunnel
)
2728 case CIRCUIT_PURPOSE_OR
:
2729 case CIRCUIT_PURPOSE_INTRO_POINT
:
2730 case CIRCUIT_PURPOSE_REND_POINT_WAITING
:
2731 case CIRCUIT_PURPOSE_REND_ESTABLISHED
:
2732 log_warn(LD_BUG
, "Called on non-origin circuit (purpose %d)",
2735 case CIRCUIT_PURPOSE_C_GENERAL
:
2736 if (circ
->build_state
->is_internal
)
2738 description
= "Requested exit node";
2739 rs
= options
->_ExcludeExitNodesUnion
;
2741 case CIRCUIT_PURPOSE_C_INTRODUCING
:
2742 case CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT
:
2743 case CIRCUIT_PURPOSE_C_INTRODUCE_ACKED
:
2744 case CIRCUIT_PURPOSE_S_ESTABLISH_INTRO
:
2745 case CIRCUIT_PURPOSE_S_CONNECT_REND
:
2746 case CIRCUIT_PURPOSE_S_REND_JOINED
:
2747 case CIRCUIT_PURPOSE_TESTING
:
2749 case CIRCUIT_PURPOSE_C_ESTABLISH_REND
:
2750 case CIRCUIT_PURPOSE_C_REND_READY
:
2751 case CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED
:
2752 case CIRCUIT_PURPOSE_C_REND_JOINED
:
2753 description
= "Chosen rendezvous point";
2756 case CIRCUIT_PURPOSE_CONTROLLER
:
2757 rs
= options
->_ExcludeExitNodesUnion
;
2758 description
= "Controller-selected circuit target";
2762 if (routerset_contains_extendinfo(rs
, exit
)) {
2763 log_fn(LOG_WARN
, domain
, "%s '%s' is in ExcludeNodes%s. Using anyway "
2764 "(circuit purpose %d).",
2765 description
,exit
->nickname
,
2766 rs
==options
->ExcludeNodes
?"":" or ExcludeExitNodes",
2768 circuit_log_path(LOG_WARN
, domain
, circ
);
2774 /** Decide a suitable length for circ's cpath, and pick an exit
2775 * router (or use <b>exit</b> if provided). Store these in the
2776 * cpath. Return 0 if ok, -1 if circuit should be closed. */
2778 onion_pick_cpath_exit(origin_circuit_t
*circ
, extend_info_t
*exit
)
2780 cpath_build_state_t
*state
= circ
->build_state
;
2781 routerlist_t
*rl
= router_get_routerlist();
2783 if (state
->onehop_tunnel
) {
2784 log_debug(LD_CIRC
, "Launching a one-hop circuit for dir tunnel.");
2785 state
->desired_path_len
= 1;
2787 int r
= new_route_len(circ
->_base
.purpose
, exit
, rl
->routers
);
2788 if (r
< 1) /* must be at least 1 */
2790 state
->desired_path_len
= r
;
2793 if (exit
) { /* the circuit-builder pre-requested one */
2794 warn_if_last_router_excluded(circ
, exit
);
2795 log_info(LD_CIRC
,"Using requested exit node '%s'", exit
->nickname
);
2796 exit
= extend_info_dup(exit
);
2797 } else { /* we have to decide one */
2798 routerinfo_t
*router
=
2799 choose_good_exit_server(circ
->_base
.purpose
, rl
, state
->need_uptime
,
2800 state
->need_capacity
, state
->is_internal
);
2802 log_warn(LD_CIRC
,"failed to choose an exit server");
2805 exit
= extend_info_from_router(router
);
2807 state
->chosen_exit
= exit
;
2811 /** Give <b>circ</b> a new exit destination to <b>exit</b>, and add a
2812 * hop to the cpath reflecting this. Don't send the next extend cell --
2813 * the caller will do this if it wants to.
2816 circuit_append_new_exit(origin_circuit_t
*circ
, extend_info_t
*exit
)
2818 cpath_build_state_t
*state
;
2822 state
= circ
->build_state
;
2824 extend_info_free(state
->chosen_exit
);
2825 state
->chosen_exit
= extend_info_dup(exit
);
2827 ++circ
->build_state
->desired_path_len
;
2828 onion_append_hop(&circ
->cpath
, exit
);
2832 /** Take an open <b>circ</b>, and add a new hop at the end, based on
2833 * <b>info</b>. Set its state back to CIRCUIT_STATE_BUILDING, and then
2834 * send the next extend cell to begin connecting to that hop.
2837 circuit_extend_to_new_exit(origin_circuit_t
*circ
, extend_info_t
*exit
)
2840 warn_if_last_router_excluded(circ
, exit
);
2841 circuit_append_new_exit(circ
, exit
);
2842 circuit_set_state(TO_CIRCUIT(circ
), CIRCUIT_STATE_BUILDING
);
2843 if ((err_reason
= circuit_send_next_onion_skin(circ
))<0) {
2844 log_warn(LD_CIRC
, "Couldn't extend circuit to new point '%s'.",
2846 circuit_mark_for_close(TO_CIRCUIT(circ
), -err_reason
);
2852 /** Return the number of routers in <b>routers</b> that are currently up
2853 * and available for building circuits through.
2856 count_acceptable_routers(smartlist_t
*routers
)
2862 n
= smartlist_len(routers
);
2864 r
= smartlist_get(routers
, i
);
2865 // log_debug(LD_CIRC,
2866 // "Contemplating whether router %d (%s) is a new option.",
2868 if (r
->is_running
== 0) {
2869 // log_debug(LD_CIRC,"Nope, the directory says %d is not running.",i);
2872 if (r
->is_valid
== 0) {
2873 // log_debug(LD_CIRC,"Nope, the directory says %d is not valid.",i);
2875 /* XXX This clause makes us count incorrectly: if AllowInvalidRouters
2876 * allows this node in some places, then we're getting an inaccurate
2877 * count. For now, be conservative and don't count it. But later we
2878 * should try to be smarter. */
2881 // log_debug(LD_CIRC,"I like %d. num_acceptable_routers now %d.",i, num);
2883 ; /* C requires an explicit statement after the label */
2889 /** Add <b>new_hop</b> to the end of the doubly-linked-list <b>head_ptr</b>.
2890 * This function is used to extend cpath by another hop.
2893 onion_append_to_cpath(crypt_path_t
**head_ptr
, crypt_path_t
*new_hop
)
2896 new_hop
->next
= (*head_ptr
);
2897 new_hop
->prev
= (*head_ptr
)->prev
;
2898 (*head_ptr
)->prev
->next
= new_hop
;
2899 (*head_ptr
)->prev
= new_hop
;
2901 *head_ptr
= new_hop
;
2902 new_hop
->prev
= new_hop
->next
= new_hop
;
2906 /** A helper function used by onion_extend_cpath(). Use <b>purpose</b>
2907 * and <b>state</b> and the cpath <b>head</b> (currently populated only
2908 * to length <b>cur_len</b> to decide a suitable middle hop for a
2909 * circuit. In particular, make sure we don't pick the exit node or its
2910 * family, and make sure we don't duplicate any previous nodes or their
2912 static routerinfo_t
*
2913 choose_good_middle_server(uint8_t purpose
,
2914 cpath_build_state_t
*state
,
2919 routerinfo_t
*r
, *choice
;
2920 crypt_path_t
*cpath
;
2921 smartlist_t
*excluded
;
2922 or_options_t
*options
= get_options();
2923 router_crn_flags_t flags
= 0;
2924 tor_assert(_CIRCUIT_PURPOSE_MIN
<= purpose
&&
2925 purpose
<= _CIRCUIT_PURPOSE_MAX
);
2927 log_debug(LD_CIRC
, "Contemplating intermediate hop: random choice.");
2928 excluded
= smartlist_create();
2929 if ((r
= build_state_get_exit_router(state
))) {
2930 smartlist_add(excluded
, r
);
2931 routerlist_add_family(excluded
, r
);
2933 for (i
= 0, cpath
= head
; i
< cur_len
; ++i
, cpath
=cpath
->next
) {
2934 if ((r
= router_get_by_digest(cpath
->extend_info
->identity_digest
))) {
2935 smartlist_add(excluded
, r
);
2936 routerlist_add_family(excluded
, r
);
2940 if (state
->need_uptime
)
2941 flags
|= CRN_NEED_UPTIME
;
2942 if (state
->need_capacity
)
2943 flags
|= CRN_NEED_CAPACITY
;
2944 if (options
->_AllowInvalid
& ALLOW_INVALID_MIDDLE
)
2945 flags
|= CRN_ALLOW_INVALID
;
2946 choice
= router_choose_random_node(excluded
, options
->ExcludeNodes
, flags
);
2947 smartlist_free(excluded
);
2951 /** Pick a good entry server for the circuit to be built according to
2952 * <b>state</b>. Don't reuse a chosen exit (if any), don't use this
2953 * router (if we're an OR), and respect firewall settings; if we're
2954 * configured to use entry guards, return one.
2956 * If <b>state</b> is NULL, we're choosing a router to serve as an entry
2957 * guard, not for any particular circuit.
2959 static routerinfo_t
*
2960 choose_good_entry_server(uint8_t purpose
, cpath_build_state_t
*state
)
2962 routerinfo_t
*r
, *choice
;
2963 smartlist_t
*excluded
;
2964 or_options_t
*options
= get_options();
2965 router_crn_flags_t flags
= CRN_NEED_GUARD
;
2967 if (state
&& options
->UseEntryGuards
&&
2968 (purpose
!= CIRCUIT_PURPOSE_TESTING
|| options
->BridgeRelay
)) {
2969 return choose_random_entry(state
);
2972 excluded
= smartlist_create();
2974 if (state
&& (r
= build_state_get_exit_router(state
))) {
2975 smartlist_add(excluded
, r
);
2976 routerlist_add_family(excluded
, r
);
2978 if (firewall_is_fascist_or()) {
2979 /*XXXX This could slow things down a lot; use a smarter implementation */
2980 /* exclude all ORs that listen on the wrong port, if anybody notices. */
2981 routerlist_t
*rl
= router_get_routerlist();
2984 for (i
=0; i
< smartlist_len(rl
->routers
); i
++) {
2985 r
= smartlist_get(rl
->routers
, i
);
2986 if (!fascist_firewall_allows_or(r
))
2987 smartlist_add(excluded
, r
);
2990 /* and exclude current entry guards, if applicable */
2991 if (options
->UseEntryGuards
&& entry_guards
) {
2992 SMARTLIST_FOREACH(entry_guards
, entry_guard_t
*, entry
,
2994 if ((r
= router_get_by_digest(entry
->identity
))) {
2995 smartlist_add(excluded
, r
);
2996 routerlist_add_family(excluded
, r
);
3002 if (state
->need_uptime
)
3003 flags
|= CRN_NEED_UPTIME
;
3004 if (state
->need_capacity
)
3005 flags
|= CRN_NEED_CAPACITY
;
3007 if (options
->_AllowInvalid
& ALLOW_INVALID_ENTRY
)
3008 flags
|= CRN_ALLOW_INVALID
;
3010 choice
= router_choose_random_node(excluded
, options
->ExcludeNodes
, flags
);
3011 smartlist_free(excluded
);
3015 /** Return the first non-open hop in cpath, or return NULL if all
3017 static crypt_path_t
*
3018 onion_next_hop_in_cpath(crypt_path_t
*cpath
)
3020 crypt_path_t
*hop
= cpath
;
3022 if (hop
->state
!= CPATH_STATE_OPEN
)
3025 } while (hop
!= cpath
);
3029 /** Choose a suitable next hop in the cpath <b>head_ptr</b>,
3030 * based on <b>state</b>. Append the hop info to head_ptr.
3033 onion_extend_cpath(origin_circuit_t
*circ
)
3035 uint8_t purpose
= circ
->_base
.purpose
;
3036 cpath_build_state_t
*state
= circ
->build_state
;
3037 int cur_len
= circuit_get_cpath_len(circ
);
3038 extend_info_t
*info
= NULL
;
3040 if (cur_len
>= state
->desired_path_len
) {
3041 log_debug(LD_CIRC
, "Path is complete: %d steps long",
3042 state
->desired_path_len
);
3046 log_debug(LD_CIRC
, "Path is %d long; we want %d", cur_len
,
3047 state
->desired_path_len
);
3049 if (cur_len
== state
->desired_path_len
- 1) { /* Picking last node */
3050 info
= extend_info_dup(state
->chosen_exit
);
3051 } else if (cur_len
== 0) { /* picking first node */
3052 routerinfo_t
*r
= choose_good_entry_server(purpose
, state
);
3054 info
= extend_info_from_router(r
);
3057 choose_good_middle_server(purpose
, state
, circ
->cpath
, cur_len
);
3059 info
= extend_info_from_router(r
);
3063 log_warn(LD_CIRC
,"Failed to find node for hop %d of our path. Discarding "
3064 "this circuit.", cur_len
);
3068 log_debug(LD_CIRC
,"Chose router %s for hop %d (exit is %s)",
3069 info
->nickname
, cur_len
+1, build_state_get_exit_nickname(state
));
3071 onion_append_hop(&circ
->cpath
, info
);
3072 extend_info_free(info
);
3076 /** Create a new hop, annotate it with information about its
3077 * corresponding router <b>choice</b>, and append it to the
3078 * end of the cpath <b>head_ptr</b>. */
3080 onion_append_hop(crypt_path_t
**head_ptr
, extend_info_t
*choice
)
3082 crypt_path_t
*hop
= tor_malloc_zero(sizeof(crypt_path_t
));
3084 /* link hop into the cpath, at the end. */
3085 onion_append_to_cpath(head_ptr
, hop
);
3087 hop
->magic
= CRYPT_PATH_MAGIC
;
3088 hop
->state
= CPATH_STATE_CLOSED
;
3090 hop
->extend_info
= extend_info_dup(choice
);
3092 hop
->package_window
= circuit_initial_package_window();
3093 hop
->deliver_window
= CIRCWINDOW_START
;
3098 /** Allocate a new extend_info object based on the various arguments. */
3100 extend_info_alloc(const char *nickname
, const char *digest
,
3101 crypto_pk_env_t
*onion_key
,
3102 const tor_addr_t
*addr
, uint16_t port
)
3104 extend_info_t
*info
= tor_malloc_zero(sizeof(extend_info_t
));
3105 memcpy(info
->identity_digest
, digest
, DIGEST_LEN
);
3107 strlcpy(info
->nickname
, nickname
, sizeof(info
->nickname
));
3109 info
->onion_key
= crypto_pk_dup_key(onion_key
);
3110 tor_addr_copy(&info
->addr
, addr
);
3115 /** Allocate and return a new extend_info_t that can be used to build a
3116 * circuit to or through the router <b>r</b>. */
3118 extend_info_from_router(routerinfo_t
*r
)
3122 tor_addr_from_ipv4h(&addr
, r
->addr
);
3123 return extend_info_alloc(r
->nickname
, r
->cache_info
.identity_digest
,
3124 r
->onion_pkey
, &addr
, r
->or_port
);
3127 /** Release storage held by an extend_info_t struct. */
3129 extend_info_free(extend_info_t
*info
)
3133 crypto_free_pk_env(info
->onion_key
);
3137 /** Allocate and return a new extend_info_t with the same contents as
3140 extend_info_dup(extend_info_t
*info
)
3142 extend_info_t
*newinfo
;
3144 newinfo
= tor_malloc(sizeof(extend_info_t
));
3145 memcpy(newinfo
, info
, sizeof(extend_info_t
));
3146 if (info
->onion_key
)
3147 newinfo
->onion_key
= crypto_pk_dup_key(info
->onion_key
);
3149 newinfo
->onion_key
= NULL
;
3153 /** Return the routerinfo_t for the chosen exit router in <b>state</b>.
3154 * If there is no chosen exit, or if we don't know the routerinfo_t for
3155 * the chosen exit, return NULL.
3158 build_state_get_exit_router(cpath_build_state_t
*state
)
3160 if (!state
|| !state
->chosen_exit
)
3162 return router_get_by_digest(state
->chosen_exit
->identity_digest
);
3165 /** Return the nickname for the chosen exit router in <b>state</b>. If
3166 * there is no chosen exit, or if we don't know the routerinfo_t for the
3167 * chosen exit, return NULL.
3170 build_state_get_exit_nickname(cpath_build_state_t
*state
)
3172 if (!state
|| !state
->chosen_exit
)
3174 return state
->chosen_exit
->nickname
;
3177 /** Check whether the entry guard <b>e</b> is usable, given the directory
3178 * authorities' opinion about the router (stored in <b>ri</b>) and the user's
3179 * configuration (in <b>options</b>). Set <b>e</b>->bad_since
3180 * accordingly. Return true iff the entry guard's status changes.
3182 * If it's not usable, set *<b>reason</b> to a static string explaining why.
3184 /*XXXX take a routerstatus, not a routerinfo. */
3186 entry_guard_set_status(entry_guard_t
*e
, routerinfo_t
*ri
,
3187 time_t now
, or_options_t
*options
, const char **reason
)
3189 char buf
[HEX_DIGEST_LEN
+1];
3192 tor_assert(options
);
3196 /* Do we want to mark this guard as bad? */
3198 *reason
= "unlisted";
3199 else if (!ri
->is_running
)
3201 else if (options
->UseBridges
&& ri
->purpose
!= ROUTER_PURPOSE_BRIDGE
)
3202 *reason
= "not a bridge";
3203 else if (!options
->UseBridges
&& !ri
->is_possible_guard
&&
3204 !routerset_contains_router(options
->EntryNodes
,ri
))
3205 *reason
= "not recommended as a guard";
3206 else if (routerset_contains_router(options
->ExcludeNodes
, ri
))
3207 *reason
= "excluded";
3209 if (*reason
&& ! e
->bad_since
) {
3210 /* Router is newly bad. */
3211 base16_encode(buf
, sizeof(buf
), e
->identity
, DIGEST_LEN
);
3212 log_info(LD_CIRC
, "Entry guard %s (%s) is %s: marking as unusable.",
3213 e
->nickname
, buf
, *reason
);
3216 control_event_guard(e
->nickname
, e
->identity
, "BAD");
3218 } else if (!*reason
&& e
->bad_since
) {
3219 /* There's nothing wrong with the router any more. */
3220 base16_encode(buf
, sizeof(buf
), e
->identity
, DIGEST_LEN
);
3221 log_info(LD_CIRC
, "Entry guard %s (%s) is no longer unusable: "
3222 "marking as ok.", e
->nickname
, buf
);
3225 control_event_guard(e
->nickname
, e
->identity
, "GOOD");
3231 /** Return true iff enough time has passed since we last tried to connect
3232 * to the unreachable guard <b>e</b> that we're willing to try again. */
3234 entry_is_time_to_retry(entry_guard_t
*e
, time_t now
)
3237 if (e
->last_attempted
< e
->unreachable_since
)
3239 diff
= now
- e
->unreachable_since
;
3241 return now
> (e
->last_attempted
+ 60*60);
3242 else if (diff
< 3*24*60*60)
3243 return now
> (e
->last_attempted
+ 4*60*60);
3244 else if (diff
< 7*24*60*60)
3245 return now
> (e
->last_attempted
+ 18*60*60);
3247 return now
> (e
->last_attempted
+ 36*60*60);
3250 /** Return the router corresponding to <b>e</b>, if <b>e</b> is
3251 * working well enough that we are willing to use it as an entry
3252 * right now. (Else return NULL.) In particular, it must be
3253 * - Listed as either up or never yet contacted;
3254 * - Present in the routerlist;
3255 * - Listed as 'stable' or 'fast' by the current dirserver consensus,
3256 * if demanded by <b>need_uptime</b> or <b>need_capacity</b>
3257 * (unless it's a configured EntryNode);
3258 * - Allowed by our current ReachableORAddresses config option; and
3259 * - Currently thought to be reachable by us (unless <b>assume_reachable</b>
3262 * If the answer is no, set *<b>msg</b> to an explanation of why.
3264 static INLINE routerinfo_t
*
3265 entry_is_live(entry_guard_t
*e
, int need_uptime
, int need_capacity
,
3266 int assume_reachable
, const char **msg
)
3269 or_options_t
*options
= get_options();
3276 /* no good if it's unreachable, unless assume_unreachable or can_retry. */
3277 if (!assume_reachable
&& !e
->can_retry
&&
3278 e
->unreachable_since
&& !entry_is_time_to_retry(e
, time(NULL
))) {
3279 *msg
= "unreachable";
3282 r
= router_get_by_digest(e
->identity
);
3284 *msg
= "no descriptor";
3287 if (get_options()->UseBridges
&& r
->purpose
!= ROUTER_PURPOSE_BRIDGE
) {
3288 *msg
= "not a bridge";
3291 if (!get_options()->UseBridges
&& r
->purpose
!= ROUTER_PURPOSE_GENERAL
) {
3292 *msg
= "not general-purpose";
3295 if (options
->EntryNodes
&&
3296 routerset_contains_router(options
->EntryNodes
, r
)) {
3297 /* they asked for it, they get it */
3298 need_uptime
= need_capacity
= 0;
3300 if (router_is_unreliable(r
, need_uptime
, need_capacity
, 0)) {
3301 *msg
= "not fast/stable";
3304 if (!fascist_firewall_allows_or(r
)) {
3305 *msg
= "unreachable by config";
3311 /** Return the number of entry guards that we think are usable. */
3313 num_live_entry_guards(void)
3319 SMARTLIST_FOREACH(entry_guards
, entry_guard_t
*, entry
,
3321 if (entry_is_live(entry
, 0, 1, 0, &msg
))
3327 /** If <b>digest</b> matches the identity of any node in the
3328 * entry_guards list, return that node. Else return NULL. */
3329 static INLINE entry_guard_t
*
3330 is_an_entry_guard(const char *digest
)
3332 SMARTLIST_FOREACH(entry_guards
, entry_guard_t
*, entry
,
3333 if (!memcmp(digest
, entry
->identity
, DIGEST_LEN
))
3339 /** Dump a description of our list of entry guards to the log at level
3340 * <b>severity</b>. */
3342 log_entry_guards(int severity
)
3344 smartlist_t
*elements
= smartlist_create();
3347 SMARTLIST_FOREACH(entry_guards
, entry_guard_t
*, e
,
3349 const char *msg
= NULL
;
3351 if (entry_is_live(e
, 0, 1, 0, &msg
))
3352 tor_asprintf(&cp
, "%s (up %s)",
3354 e
->made_contact
? "made-contact" : "never-contacted");
3356 tor_asprintf(&cp
, "%s (%s, %s)",
3358 e
->made_contact
? "made-contact" : "never-contacted");
3359 smartlist_add(elements
, cp
);
3362 s
= smartlist_join_strings(elements
, ",", 0, NULL
);
3363 SMARTLIST_FOREACH(elements
, char*, cp
, tor_free(cp
));
3364 smartlist_free(elements
);
3365 log_fn(severity
,LD_CIRC
,"%s",s
);
3369 /** Called when one or more guards that we would previously have used for some
3370 * purpose are no longer in use because a higher-priority guard has become
3373 control_event_guard_deferred(void)
3375 /* XXXX We don't actually have a good way to figure out _how many_ entries
3376 * are live for some purpose. We need an entry_is_even_slightly_live()
3377 * function for this to work right. NumEntryGuards isn't reliable: if we
3378 * need guards with weird properties, we can have more than that number
3384 or_options_t
*options
= get_options();
3387 SMARTLIST_FOREACH(entry_guards
, entry_guard_t
*, entry
,
3389 if (entry_is_live(entry
, 0, 1, 0, &msg
)) {
3390 if (n
++ == options
->NumEntryGuards
) {
3391 control_event_guard(entry
->nickname
, entry
->identity
, "DEFERRED");
3399 /** Add a new (preferably stable and fast) router to our
3400 * entry_guards list. Return a pointer to the router if we succeed,
3401 * or NULL if we can't find any more suitable entries.
3403 * If <b>chosen</b> is defined, use that one, and if it's not
3404 * already in our entry_guards list, put it at the *beginning*.
3405 * Else, put the one we pick at the end of the list. */
3406 static routerinfo_t
*
3407 add_an_entry_guard(routerinfo_t
*chosen
, int reset_status
)
3409 routerinfo_t
*router
;
3410 entry_guard_t
*entry
;
3414 entry
= is_an_entry_guard(router
->cache_info
.identity_digest
);
3417 entry
->bad_since
= 0;
3418 entry
->can_retry
= 1;
3423 router
= choose_good_entry_server(CIRCUIT_PURPOSE_C_GENERAL
, NULL
);
3427 entry
= tor_malloc_zero(sizeof(entry_guard_t
));
3428 log_info(LD_CIRC
, "Chose '%s' as new entry guard.", router
->nickname
);
3429 strlcpy(entry
->nickname
, router
->nickname
, sizeof(entry
->nickname
));
3430 memcpy(entry
->identity
, router
->cache_info
.identity_digest
, DIGEST_LEN
);
3431 /* Choose expiry time smudged over the past month. The goal here
3432 * is to a) spread out when Tor clients rotate their guards, so they
3433 * don't all select them on the same day, and b) avoid leaving a
3434 * precise timestamp in the state file about when we first picked
3435 * this guard. For details, see the Jan 2010 or-dev thread. */
3436 entry
->chosen_on_date
= time(NULL
) - crypto_rand_int(3600*24*30);
3437 entry
->chosen_by_version
= tor_strdup(VERSION
);
3438 if (chosen
) /* prepend */
3439 smartlist_insert(entry_guards
, 0, entry
);
3441 smartlist_add(entry_guards
, entry
);
3442 control_event_guard(entry
->nickname
, entry
->identity
, "NEW");
3443 control_event_guard_deferred();
3444 log_entry_guards(LOG_INFO
);
3448 /** If the use of entry guards is configured, choose more entry guards
3449 * until we have enough in the list. */
3451 pick_entry_guards(void)
3453 or_options_t
*options
= get_options();
3456 tor_assert(entry_guards
);
3458 while (num_live_entry_guards() < options
->NumEntryGuards
) {
3459 if (!add_an_entry_guard(NULL
, 0))
3464 entry_guards_changed();
3467 /** How long (in seconds) do we allow an entry guard to be nonfunctional,
3468 * unlisted, excluded, or otherwise nonusable before we give up on it? */
3469 #define ENTRY_GUARD_REMOVE_AFTER (30*24*60*60)
3471 /** Release all storage held by <b>e</b>. */
3473 entry_guard_free(entry_guard_t
*e
)
3477 tor_free(e
->chosen_by_version
);
3481 /** Remove any entry guard which was selected by an unknown version of Tor,
3482 * or which was selected by a version of Tor that's known to select
3483 * entry guards badly. */
3485 remove_obsolete_entry_guards(void)
3488 time_t now
= time(NULL
);
3490 for (i
= 0; i
< smartlist_len(entry_guards
); ++i
) {
3491 entry_guard_t
*entry
= smartlist_get(entry_guards
, i
);
3492 const char *ver
= entry
->chosen_by_version
;
3493 const char *msg
= NULL
;
3495 int version_is_bad
= 0, date_is_bad
= 0;
3497 msg
= "does not say what version of Tor it was selected by";
3499 } else if (tor_version_parse(ver
, &v
)) {
3500 msg
= "does not seem to be from any recognized version of Tor";
3503 size_t len
= strlen(ver
)+5;
3504 char *tor_ver
= tor_malloc(len
);
3505 tor_snprintf(tor_ver
, len
, "Tor %s", ver
);
3506 if ((tor_version_as_new_as(tor_ver
, "0.1.0.10-alpha") &&
3507 !tor_version_as_new_as(tor_ver
, "0.1.2.16-dev")) ||
3508 (tor_version_as_new_as(tor_ver
, "0.2.0.0-alpha") &&
3509 !tor_version_as_new_as(tor_ver
, "0.2.0.6-alpha")) ||
3510 /* above are bug 440; below are bug 1217 */
3511 (tor_version_as_new_as(tor_ver
, "0.2.1.3-alpha") &&
3512 !tor_version_as_new_as(tor_ver
, "0.2.1.23")) ||
3513 (tor_version_as_new_as(tor_ver
, "0.2.2.0-alpha") &&
3514 !tor_version_as_new_as(tor_ver
, "0.2.2.7-alpha"))) {
3515 msg
= "was selected without regard for guard bandwidth";
3520 if (!version_is_bad
&& entry
->chosen_on_date
+ 3600*24*60 < now
) {
3521 /* It's been 2 months since the date listed in our state file. */
3522 msg
= "was selected several months ago";
3526 if (version_is_bad
|| date_is_bad
) { /* we need to drop it */
3527 char dbuf
[HEX_DIGEST_LEN
+1];
3529 base16_encode(dbuf
, sizeof(dbuf
), entry
->identity
, DIGEST_LEN
);
3530 log_fn(version_is_bad
? LOG_NOTICE
: LOG_INFO
, LD_CIRC
,
3531 "Entry guard '%s' (%s) %s. (Version=%s.) Replacing it.",
3532 entry
->nickname
, dbuf
, msg
, ver
?escaped(ver
):"none");
3533 control_event_guard(entry
->nickname
, entry
->identity
, "DROPPED");
3534 entry_guard_free(entry
);
3535 smartlist_del_keeporder(entry_guards
, i
--);
3536 log_entry_guards(LOG_INFO
);
3541 return changed
? 1 : 0;
3544 /** Remove all entry guards that have been down or unlisted for so
3545 * long that we don't think they'll come up again. Return 1 if we
3546 * removed any, or 0 if we did nothing. */
3548 remove_dead_entry_guards(void)
3550 char dbuf
[HEX_DIGEST_LEN
+1];
3551 char tbuf
[ISO_TIME_LEN
+1];
3552 time_t now
= time(NULL
);
3556 for (i
= 0; i
< smartlist_len(entry_guards
); ) {
3557 entry_guard_t
*entry
= smartlist_get(entry_guards
, i
);
3558 if (entry
->bad_since
&&
3559 entry
->bad_since
+ ENTRY_GUARD_REMOVE_AFTER
< now
) {
3561 base16_encode(dbuf
, sizeof(dbuf
), entry
->identity
, DIGEST_LEN
);
3562 format_local_iso_time(tbuf
, entry
->bad_since
);
3563 log_info(LD_CIRC
, "Entry guard '%s' (%s) has been down or unlisted "
3564 "since %s local time; removing.",
3565 entry
->nickname
, dbuf
, tbuf
);
3566 control_event_guard(entry
->nickname
, entry
->identity
, "DROPPED");
3567 entry_guard_free(entry
);
3568 smartlist_del_keeporder(entry_guards
, i
);
3569 log_entry_guards(LOG_INFO
);
3574 return changed
? 1 : 0;
3577 /** A new directory or router-status has arrived; update the down/listed
3578 * status of the entry guards.
3580 * An entry is 'down' if the directory lists it as nonrunning.
3581 * An entry is 'unlisted' if the directory doesn't include it.
3583 * Don't call this on startup; only on a fresh download. Otherwise we'll
3584 * think that things are unlisted.
3587 entry_guards_compute_status(void)
3591 int severity
= LOG_DEBUG
;
3592 or_options_t
*options
;
3593 digestmap_t
*reasons
;
3598 options
= get_options();
3599 if (options
->EntryNodes
) /* reshuffle the entry guard list if needed */
3600 entry_nodes_should_be_added();
3604 reasons
= digestmap_new();
3605 SMARTLIST_FOREACH_BEGIN(entry_guards
, entry_guard_t
*, entry
)
3607 routerinfo_t
*r
= router_get_by_digest(entry
->identity
);
3608 const char *reason
= NULL
;
3609 if (entry_guard_set_status(entry
, r
, now
, options
, &reason
))
3612 if (entry
->bad_since
)
3615 digestmap_set(reasons
, entry
->identity
, (char*)reason
);
3617 SMARTLIST_FOREACH_END(entry
);
3619 if (remove_dead_entry_guards())
3622 severity
= changed
? LOG_DEBUG
: LOG_INFO
;
3625 SMARTLIST_FOREACH_BEGIN(entry_guards
, entry_guard_t
*, entry
) {
3626 const char *reason
= digestmap_get(reasons
, entry
->identity
);
3627 const char *live_msg
= "";
3628 routerinfo_t
*r
= entry_is_live(entry
, 0, 1, 0, &live_msg
);
3629 log_info(LD_CIRC
, "Summary: Entry '%s' is %s, %s%s%s, and %s%s.",
3631 entry
->unreachable_since
? "unreachable" : "reachable",
3632 entry
->bad_since
? "unusable" : "usable",
3634 reason
? reason
: "",
3635 r
? "live" : "not live / ",
3637 } SMARTLIST_FOREACH_END(entry
);
3638 log_info(LD_CIRC
, " (%d/%d entry guards are usable/new)",
3639 num_live_entry_guards(), smartlist_len(entry_guards
));
3640 log_entry_guards(LOG_INFO
);
3641 entry_guards_changed();
3644 digestmap_free(reasons
, NULL
);
3647 /** Called when a connection to an OR with the identity digest <b>digest</b>
3648 * is established (<b>succeeded</b>==1) or has failed (<b>succeeded</b>==0).
3649 * If the OR is an entry, change that entry's up/down status.
3650 * Return 0 normally, or -1 if we want to tear down the new connection.
3652 * If <b>mark_relay_status</b>, also call router_set_status() on this
3655 * XXX022 change succeeded and mark_relay_status into 'int flags'.
3658 entry_guard_register_connect_status(const char *digest
, int succeeded
,
3659 int mark_relay_status
, time_t now
)
3662 int refuse_conn
= 0;
3663 int first_contact
= 0;
3664 entry_guard_t
*entry
= NULL
;
3666 char buf
[HEX_DIGEST_LEN
+1];
3671 SMARTLIST_FOREACH(entry_guards
, entry_guard_t
*, e
,
3673 if (!memcmp(e
->identity
, digest
, DIGEST_LEN
)) {
3683 base16_encode(buf
, sizeof(buf
), entry
->identity
, DIGEST_LEN
);
3686 if (entry
->unreachable_since
) {
3687 log_info(LD_CIRC
, "Entry guard '%s' (%s) is now reachable again. Good.",
3688 entry
->nickname
, buf
);
3689 entry
->can_retry
= 0;
3690 entry
->unreachable_since
= 0;
3691 entry
->last_attempted
= now
;
3692 control_event_guard(entry
->nickname
, entry
->identity
, "UP");
3695 if (!entry
->made_contact
) {
3696 entry
->made_contact
= 1;
3697 first_contact
= changed
= 1;
3699 } else { /* ! succeeded */
3700 if (!entry
->made_contact
) {
3701 /* We've never connected to this one. */
3703 "Connection to never-contacted entry guard '%s' (%s) failed. "
3704 "Removing from the list. %d/%d entry guards usable/new.",
3705 entry
->nickname
, buf
,
3706 num_live_entry_guards()-1, smartlist_len(entry_guards
)-1);
3707 control_event_guard(entry
->nickname
, entry
->identity
, "DROPPED");
3708 entry_guard_free(entry
);
3709 smartlist_del_keeporder(entry_guards
, idx
);
3710 log_entry_guards(LOG_INFO
);
3712 } else if (!entry
->unreachable_since
) {
3713 log_info(LD_CIRC
, "Unable to connect to entry guard '%s' (%s). "
3714 "Marking as unreachable.", entry
->nickname
, buf
);
3715 entry
->unreachable_since
= entry
->last_attempted
= now
;
3716 control_event_guard(entry
->nickname
, entry
->identity
, "DOWN");
3718 entry
->can_retry
= 0; /* We gave it an early chance; no good. */
3720 char tbuf
[ISO_TIME_LEN
+1];
3721 format_iso_time(tbuf
, entry
->unreachable_since
);
3722 log_debug(LD_CIRC
, "Failed to connect to unreachable entry guard "
3723 "'%s' (%s). It has been unreachable since %s.",
3724 entry
->nickname
, buf
, tbuf
);
3725 entry
->last_attempted
= now
;
3726 entry
->can_retry
= 0; /* We gave it an early chance; no good. */
3730 /* if the caller asked us to, also update the is_running flags for this
3732 if (mark_relay_status
)
3733 router_set_status(digest
, succeeded
);
3735 if (first_contact
) {
3736 /* We've just added a new long-term entry guard. Perhaps the network just
3737 * came back? We should give our earlier entries another try too,
3738 * and close this connection so we don't use it before we've given
3739 * the others a shot. */
3740 SMARTLIST_FOREACH(entry_guards
, entry_guard_t
*, e
, {
3743 if (e
->made_contact
) {
3745 routerinfo_t
*r
= entry_is_live(e
, 0, 1, 1, &msg
);
3746 if (r
&& e
->unreachable_since
) {
3754 "Connected to new entry guard '%s' (%s). Marking earlier "
3755 "entry guards up. %d/%d entry guards usable/new.",
3756 entry
->nickname
, buf
,
3757 num_live_entry_guards(), smartlist_len(entry_guards
));
3758 log_entry_guards(LOG_INFO
);
3764 entry_guards_changed();
3765 return refuse_conn
? -1 : 0;
3768 /** When we try to choose an entry guard, should we parse and add
3769 * config's EntryNodes first? */
3770 static int should_add_entry_nodes
= 0;
3772 /** Called when the value of EntryNodes changes in our configuration. */
3774 entry_nodes_should_be_added(void)
3776 log_info(LD_CIRC
, "EntryNodes config option set. Putting configured "
3777 "relays at the front of the entry guard list.");
3778 should_add_entry_nodes
= 1;
3781 /** Add all nodes in EntryNodes that aren't currently guard nodes to the list
3782 * of guard nodes, at the front. */
3784 entry_guards_prepend_from_config(void)
3786 or_options_t
*options
= get_options();
3787 smartlist_t
*entry_routers
, *entry_fps
;
3788 smartlist_t
*old_entry_guards_on_list
, *old_entry_guards_not_on_list
;
3789 tor_assert(entry_guards
);
3791 should_add_entry_nodes
= 0;
3793 if (!options
->EntryNodes
) {
3794 /* It's possible that a controller set EntryNodes, thus making
3795 * should_add_entry_nodes set, then cleared it again, all before the
3796 * call to choose_random_entry() that triggered us. If so, just return.
3802 char *string
= routerset_to_string(options
->EntryNodes
);
3803 log_info(LD_CIRC
,"Adding configured EntryNodes '%s'.", string
);
3807 entry_routers
= smartlist_create();
3808 entry_fps
= smartlist_create();
3809 old_entry_guards_on_list
= smartlist_create();
3810 old_entry_guards_not_on_list
= smartlist_create();
3812 /* Split entry guards into those on the list and those not. */
3814 /* XXXX022 Now that we allow countries and IP ranges in EntryNodes, this is
3815 * potentially an enormous list. For now, we disable such values for
3816 * EntryNodes in options_validate(); really, this wants a better solution.
3817 * Perhaps we should do this calculation once whenever the list of routers
3818 * changes or the entrynodes setting changes.
3820 routerset_get_all_routers(entry_routers
, options
->EntryNodes
, 0);
3821 SMARTLIST_FOREACH(entry_routers
, routerinfo_t
*, ri
,
3822 smartlist_add(entry_fps
,ri
->cache_info
.identity_digest
));
3823 SMARTLIST_FOREACH(entry_guards
, entry_guard_t
*, e
, {
3824 if (smartlist_digest_isin(entry_fps
, e
->identity
))
3825 smartlist_add(old_entry_guards_on_list
, e
);
3827 smartlist_add(old_entry_guards_not_on_list
, e
);
3830 /* Remove all currently configured entry guards from entry_routers. */
3831 SMARTLIST_FOREACH(entry_routers
, routerinfo_t
*, ri
, {
3832 if (is_an_entry_guard(ri
->cache_info
.identity_digest
)) {
3833 SMARTLIST_DEL_CURRENT(entry_routers
, ri
);
3837 /* Now build the new entry_guards list. */
3838 smartlist_clear(entry_guards
);
3839 /* First, the previously configured guards that are in EntryNodes. */
3840 smartlist_add_all(entry_guards
, old_entry_guards_on_list
);
3841 /* Next, the rest of EntryNodes */
3842 SMARTLIST_FOREACH(entry_routers
, routerinfo_t
*, ri
, {
3843 add_an_entry_guard(ri
, 0);
3845 /* Finally, the remaining previously configured guards that are not in
3846 * EntryNodes, unless we're strict in which case we drop them */
3847 if (options
->StrictNodes
) {
3848 SMARTLIST_FOREACH(old_entry_guards_not_on_list
, entry_guard_t
*, e
,
3849 entry_guard_free(e
));
3851 smartlist_add_all(entry_guards
, old_entry_guards_not_on_list
);
3854 smartlist_free(entry_routers
);
3855 smartlist_free(entry_fps
);
3856 smartlist_free(old_entry_guards_on_list
);
3857 smartlist_free(old_entry_guards_not_on_list
);
3858 entry_guards_changed();
3861 /** Return 0 if we're fine adding arbitrary routers out of the
3862 * directory to our entry guard list, or return 1 if we have a
3863 * list already and we'd prefer to stick to it.
3866 entry_list_is_constrained(or_options_t
*options
)
3868 if (options
->EntryNodes
)
3870 if (options
->UseBridges
)
3875 /* Are we dead set against changing our entry guard list, or would we
3876 * change it if it means keeping Tor usable? */
3878 entry_list_is_totally_static(or_options_t
*options
)
3880 if (options
->EntryNodes
&& options
->StrictNodes
)
3882 if (options
->UseBridges
)
3887 /** Pick a live (up and listed) entry guard from entry_guards. If
3888 * <b>state</b> is non-NULL, this is for a specific circuit --
3889 * make sure not to pick this circuit's exit or any node in the
3890 * exit's family. If <b>state</b> is NULL, we're looking for a random
3891 * guard (likely a bridge). */
3893 choose_random_entry(cpath_build_state_t
*state
)
3895 or_options_t
*options
= get_options();
3896 smartlist_t
*live_entry_guards
= smartlist_create();
3897 smartlist_t
*exit_family
= smartlist_create();
3898 routerinfo_t
*chosen_exit
= state
?build_state_get_exit_router(state
) : NULL
;
3899 routerinfo_t
*r
= NULL
;
3900 int need_uptime
= state
? state
->need_uptime
: 0;
3901 int need_capacity
= state
? state
->need_capacity
: 0;
3902 int preferred_min
, consider_exit_family
= 0;
3905 smartlist_add(exit_family
, chosen_exit
);
3906 routerlist_add_family(exit_family
, chosen_exit
);
3907 consider_exit_family
= 1;
3911 entry_guards
= smartlist_create();
3913 if (should_add_entry_nodes
)
3914 entry_guards_prepend_from_config();
3916 if (!entry_list_is_constrained(options
) &&
3917 smartlist_len(entry_guards
) < options
->NumEntryGuards
)
3918 pick_entry_guards();
3921 smartlist_clear(live_entry_guards
);
3922 SMARTLIST_FOREACH(entry_guards
, entry_guard_t
*, entry
,
3925 r
= entry_is_live(entry
, need_uptime
, need_capacity
, 0, &msg
);
3927 continue; /* down, no point */
3928 if (consider_exit_family
&& smartlist_isin(exit_family
, r
))
3929 continue; /* avoid relays that are family members of our exit */
3930 if (options
->EntryNodes
&&
3931 !routerset_contains_router(options
->EntryNodes
, r
)) {
3932 /* We've come to the end of our preferred entry nodes. */
3933 if (smartlist_len(live_entry_guards
))
3934 goto choose_and_finish
; /* only choose from the ones we like */
3935 if (options
->StrictNodes
) {
3936 /* in theory this case should never happen, since
3937 * entry_guards_prepend_from_config() drops unwanted relays */
3938 tor_fragile_assert();
3941 "No relays from EntryNodes available. Using others.");
3944 smartlist_add(live_entry_guards
, r
);
3945 if (!entry
->made_contact
) {
3946 /* Always start with the first not-yet-contacted entry
3947 * guard. Otherwise we might add several new ones, pick
3948 * the second new one, and now we've expanded our entry
3949 * guard list without needing to. */
3950 goto choose_and_finish
;
3952 if (smartlist_len(live_entry_guards
) >= options
->NumEntryGuards
)
3953 break; /* we have enough */
3956 if (entry_list_is_constrained(options
)) {
3957 /* If we prefer the entry nodes we've got, and we have at least
3958 * one choice, that's great. Use it. */
3961 /* Try to have at least 2 choices available. This way we don't
3962 * get stuck with a single live-but-crummy entry and just keep
3964 * (We might get 2 live-but-crummy entry guards, but so be it.) */
3968 if (smartlist_len(live_entry_guards
) < preferred_min
) {
3969 if (!entry_list_is_totally_static(options
)) {
3970 /* still no? try adding a new entry then */
3971 /* XXX if guard doesn't imply fast and stable, then we need
3972 * to tell add_an_entry_guard below what we want, or it might
3973 * be a long time til we get it. -RD */
3974 r
= add_an_entry_guard(NULL
, 0);
3976 entry_guards_changed();
3977 /* XXX we start over here in case the new node we added shares
3978 * a family with our exit node. There's a chance that we'll just
3979 * load up on entry guards here, if the network we're using is
3980 * one big family. Perhaps we should teach add_an_entry_guard()
3981 * to understand nodes-to-avoid-if-possible? -RD */
3985 if (!r
&& need_uptime
) {
3986 need_uptime
= 0; /* try without that requirement */
3989 if (!r
&& need_capacity
) {
3990 /* still no? last attempt, try without requiring capacity */
3994 if (!r
&& entry_list_is_constrained(options
) && consider_exit_family
) {
3995 /* still no? if we're using bridges or have strictentrynodes
3996 * set, and our chosen exit is in the same family as all our
3997 * bridges/entry guards, then be flexible about families. */
3998 consider_exit_family
= 0;
4001 /* live_entry_guards may be empty below. Oh well, we tried. */
4005 if (entry_list_is_constrained(options
)) {
4006 /* We need to weight by bandwidth, because our bridges or entryguards
4007 * were not already selected proportional to their bandwidth. */
4008 r
= routerlist_sl_choose_by_bandwidth(live_entry_guards
, WEIGHT_FOR_GUARD
);
4010 /* We choose uniformly at random here, because choose_good_entry_server()
4011 * already weights its choices by bandwidth, so we don't want to
4012 * *double*-weight our guard selection. */
4013 r
= smartlist_choose(live_entry_guards
);
4015 smartlist_free(live_entry_guards
);
4016 smartlist_free(exit_family
);
4020 /** Parse <b>state</b> and learn about the entry guards it describes.
4021 * If <b>set</b> is true, and there are no errors, replace the global
4022 * entry_list with what we find.
4023 * On success, return 0. On failure, alloc into *<b>msg</b> a string
4024 * describing the error, and return -1.
4027 entry_guards_parse_state(or_state_t
*state
, int set
, char **msg
)
4029 entry_guard_t
*node
= NULL
;
4030 smartlist_t
*new_entry_guards
= smartlist_create();
4031 config_line_t
*line
;
4032 time_t now
= time(NULL
);
4033 const char *state_version
= state
->TorVersion
;
4034 digestmap_t
*added_by
= digestmap_new();
4037 for (line
= state
->EntryGuards
; line
; line
= line
->next
) {
4038 if (!strcasecmp(line
->key
, "EntryGuard")) {
4039 smartlist_t
*args
= smartlist_create();
4040 node
= tor_malloc_zero(sizeof(entry_guard_t
));
4041 /* all entry guards on disk have been contacted */
4042 node
->made_contact
= 1;
4043 smartlist_add(new_entry_guards
, node
);
4044 smartlist_split_string(args
, line
->value
, " ",
4045 SPLIT_SKIP_SPACE
|SPLIT_IGNORE_BLANK
, 0);
4046 if (smartlist_len(args
)<2) {
4047 *msg
= tor_strdup("Unable to parse entry nodes: "
4048 "Too few arguments to EntryGuard");
4049 } else if (!is_legal_nickname(smartlist_get(args
,0))) {
4050 *msg
= tor_strdup("Unable to parse entry nodes: "
4051 "Bad nickname for EntryGuard");
4053 strlcpy(node
->nickname
, smartlist_get(args
,0), MAX_NICKNAME_LEN
+1);
4054 if (base16_decode(node
->identity
, DIGEST_LEN
, smartlist_get(args
,1),
4055 strlen(smartlist_get(args
,1)))<0) {
4056 *msg
= tor_strdup("Unable to parse entry nodes: "
4057 "Bad hex digest for EntryGuard");
4060 SMARTLIST_FOREACH(args
, char*, cp
, tor_free(cp
));
4061 smartlist_free(args
);
4064 } else if (!strcasecmp(line
->key
, "EntryGuardDownSince") ||
4065 !strcasecmp(line
->key
, "EntryGuardUnlistedSince")) {
4067 time_t last_try
= 0;
4069 *msg
= tor_strdup("Unable to parse entry nodes: "
4070 "EntryGuardDownSince/UnlistedSince without EntryGuard");
4073 if (parse_iso_time(line
->value
, &when
)<0) {
4074 *msg
= tor_strdup("Unable to parse entry nodes: "
4075 "Bad time in EntryGuardDownSince/UnlistedSince");
4079 /* It's a bad idea to believe info in the future: you can wind
4080 * up with timeouts that aren't allowed to happen for years. */
4083 if (strlen(line
->value
) >= ISO_TIME_LEN
+ISO_TIME_LEN
+1) {
4084 /* ignore failure */
4085 (void) parse_iso_time(line
->value
+ISO_TIME_LEN
+1, &last_try
);
4087 if (!strcasecmp(line
->key
, "EntryGuardDownSince")) {
4088 node
->unreachable_since
= when
;
4089 node
->last_attempted
= last_try
;
4091 node
->bad_since
= when
;
4093 } else if (!strcasecmp(line
->key
, "EntryGuardAddedBy")) {
4095 /* format is digest version date */
4096 if (strlen(line
->value
) < HEX_DIGEST_LEN
+1+1+1+ISO_TIME_LEN
) {
4097 log_warn(LD_BUG
, "EntryGuardAddedBy line is not long enough.");
4100 if (base16_decode(d
, sizeof(d
), line
->value
, HEX_DIGEST_LEN
)<0 ||
4101 line
->value
[HEX_DIGEST_LEN
] != ' ') {
4102 log_warn(LD_BUG
, "EntryGuardAddedBy line %s does not begin with "
4103 "hex digest", escaped(line
->value
));
4106 digestmap_set(added_by
, d
, tor_strdup(line
->value
+HEX_DIGEST_LEN
+1));
4108 log_warn(LD_BUG
, "Unexpected key %s", line
->key
);
4112 SMARTLIST_FOREACH(new_entry_guards
, entry_guard_t
*, e
,
4115 char *val
= digestmap_get(added_by
, e
->identity
);
4116 if (val
&& (sp
= strchr(val
, ' '))) {
4119 if (parse_iso_time(sp
, &when
)<0) {
4120 log_warn(LD_BUG
, "Can't read time %s in EntryGuardAddedBy", sp
);
4122 e
->chosen_by_version
= tor_strdup(val
);
4123 e
->chosen_on_date
= when
;
4126 if (state_version
) {
4127 e
->chosen_by_version
= tor_strdup(state_version
);
4128 e
->chosen_on_date
= time(NULL
) - crypto_rand_int(3600*24*30);
4134 SMARTLIST_FOREACH(new_entry_guards
, entry_guard_t
*, e
,
4135 entry_guard_free(e
));
4136 smartlist_free(new_entry_guards
);
4137 } else { /* !err && set */
4139 SMARTLIST_FOREACH(entry_guards
, entry_guard_t
*, e
,
4140 entry_guard_free(e
));
4141 smartlist_free(entry_guards
);
4143 entry_guards
= new_entry_guards
;
4144 entry_guards_dirty
= 0;
4145 /* XXX022 hand new_entry_guards to this func, and move it up a
4146 * few lines, so we don't have to re-dirty it */
4147 if (remove_obsolete_entry_guards())
4148 entry_guards_dirty
= 1;
4150 digestmap_free(added_by
, _tor_free
);
4151 return *msg
? -1 : 0;
4154 /** Our list of entry guards has changed, or some element of one
4155 * of our entry guards has changed. Write the changes to disk within
4156 * the next few minutes.
4159 entry_guards_changed(void)
4162 entry_guards_dirty
= 1;
4164 /* or_state_save() will call entry_guards_update_state(). */
4165 when
= get_options()->AvoidDiskWrites
? time(NULL
) + 3600 : time(NULL
)+600;
4166 or_state_mark_dirty(get_or_state(), when
);
4169 /** If the entry guard info has not changed, do nothing and return.
4170 * Otherwise, free the EntryGuards piece of <b>state</b> and create
4171 * a new one out of the global entry_guards list, and then mark
4172 * <b>state</b> dirty so it will get saved to disk.
4175 entry_guards_update_state(or_state_t
*state
)
4177 config_line_t
**next
, *line
;
4178 if (! entry_guards_dirty
)
4181 config_free_lines(state
->EntryGuards
);
4182 next
= &state
->EntryGuards
;
4185 entry_guards
= smartlist_create();
4186 SMARTLIST_FOREACH(entry_guards
, entry_guard_t
*, e
,
4188 char dbuf
[HEX_DIGEST_LEN
+1];
4189 if (!e
->made_contact
)
4190 continue; /* don't write this one to disk */
4191 *next
= line
= tor_malloc_zero(sizeof(config_line_t
));
4192 line
->key
= tor_strdup("EntryGuard");
4193 line
->value
= tor_malloc(HEX_DIGEST_LEN
+MAX_NICKNAME_LEN
+2);
4194 base16_encode(dbuf
, sizeof(dbuf
), e
->identity
, DIGEST_LEN
);
4195 tor_snprintf(line
->value
,HEX_DIGEST_LEN
+MAX_NICKNAME_LEN
+2,
4196 "%s %s", e
->nickname
, dbuf
);
4197 next
= &(line
->next
);
4198 if (e
->unreachable_since
) {
4199 *next
= line
= tor_malloc_zero(sizeof(config_line_t
));
4200 line
->key
= tor_strdup("EntryGuardDownSince");
4201 line
->value
= tor_malloc(ISO_TIME_LEN
+1+ISO_TIME_LEN
+1);
4202 format_iso_time(line
->value
, e
->unreachable_since
);
4203 if (e
->last_attempted
) {
4204 line
->value
[ISO_TIME_LEN
] = ' ';
4205 format_iso_time(line
->value
+ISO_TIME_LEN
+1, e
->last_attempted
);
4207 next
= &(line
->next
);
4210 *next
= line
= tor_malloc_zero(sizeof(config_line_t
));
4211 line
->key
= tor_strdup("EntryGuardUnlistedSince");
4212 line
->value
= tor_malloc(ISO_TIME_LEN
+1);
4213 format_iso_time(line
->value
, e
->bad_since
);
4214 next
= &(line
->next
);
4216 if (e
->chosen_on_date
&& e
->chosen_by_version
&&
4217 !strchr(e
->chosen_by_version
, ' ')) {
4218 char d
[HEX_DIGEST_LEN
+1];
4219 char t
[ISO_TIME_LEN
+1];
4221 *next
= line
= tor_malloc_zero(sizeof(config_line_t
));
4222 line
->key
= tor_strdup("EntryGuardAddedBy");
4223 val_len
= (HEX_DIGEST_LEN
+1+strlen(e
->chosen_by_version
)
4225 line
->value
= tor_malloc(val_len
);
4226 base16_encode(d
, sizeof(d
), e
->identity
, DIGEST_LEN
);
4227 format_iso_time(t
, e
->chosen_on_date
);
4228 tor_snprintf(line
->value
, val_len
, "%s %s %s",
4229 d
, e
->chosen_by_version
, t
);
4230 next
= &(line
->next
);
4233 if (!get_options()->AvoidDiskWrites
)
4234 or_state_mark_dirty(get_or_state(), 0);
4235 entry_guards_dirty
= 0;
4238 /** If <b>question</b> is the string "entry-guards", then dump
4239 * to *<b>answer</b> a newly allocated string describing all of
4240 * the nodes in the global entry_guards list. See control-spec.txt
4242 * For backward compatibility, we also handle the string "helper-nodes".
4245 getinfo_helper_entry_guards(control_connection_t
*conn
,
4246 const char *question
, char **answer
,
4247 const char **errmsg
)
4252 if (!strcmp(question
,"entry-guards") ||
4253 !strcmp(question
,"helper-nodes")) {
4254 smartlist_t
*sl
= smartlist_create();
4255 char tbuf
[ISO_TIME_LEN
+1];
4256 char nbuf
[MAX_VERBOSE_NICKNAME_LEN
+1];
4258 entry_guards
= smartlist_create();
4259 SMARTLIST_FOREACH_BEGIN(entry_guards
, entry_guard_t
*, e
) {
4260 size_t len
= MAX_VERBOSE_NICKNAME_LEN
+ISO_TIME_LEN
+32;
4261 char *c
= tor_malloc(len
);
4262 const char *status
= NULL
;
4266 if (!e
->made_contact
) {
4267 status
= "never-connected";
4268 } else if (e
->bad_since
) {
4269 when
= e
->bad_since
;
4270 status
= "unusable";
4275 ri
= router_get_by_digest(e
->identity
);
4277 router_get_verbose_nickname(nbuf
, ri
);
4280 base16_encode(nbuf
+1, sizeof(nbuf
)-1, e
->identity
, DIGEST_LEN
);
4281 /* e->nickname field is not very reliable if we don't know about
4282 * this router any longer; don't include it. */
4286 format_iso_time(tbuf
, when
);
4287 tor_snprintf(c
, len
, "%s %s %s\n", nbuf
, status
, tbuf
);
4289 tor_snprintf(c
, len
, "%s %s\n", nbuf
, status
);
4291 smartlist_add(sl
, c
);
4292 } SMARTLIST_FOREACH_END(e
);
4293 *answer
= smartlist_join_strings(sl
, "", 0, NULL
);
4294 SMARTLIST_FOREACH(sl
, char *, c
, tor_free(c
));
4300 /** Information about a configured bridge. Currently this just matches the
4301 * ones in the torrc file, but one day we may be able to learn about new
4302 * bridges on our own, and remember them in the state file. */
4304 /** Address of the bridge. */
4306 /** TLS port for the bridge. */
4308 /** Expected identity digest, or all zero bytes if we don't know what the
4309 * digest should be. */
4310 char identity
[DIGEST_LEN
];
4311 /** When should we next try to fetch a descriptor for this bridge? */
4312 download_status_t fetch_status
;
4315 /** A list of configured bridges. Whenever we actually get a descriptor
4316 * for one, we add it as an entry guard. */
4317 static smartlist_t
*bridge_list
= NULL
;
4319 /** Initialize the bridge list to empty, creating it if needed. */
4321 clear_bridge_list(void)
4324 bridge_list
= smartlist_create();
4325 SMARTLIST_FOREACH(bridge_list
, bridge_info_t
*, b
, tor_free(b
));
4326 smartlist_clear(bridge_list
);
4329 /** Return a bridge pointer if <b>ri</b> is one of our known bridges
4330 * (either by comparing keys if possible, else by comparing addr/port).
4331 * Else return NULL. */
4332 static bridge_info_t
*
4333 get_configured_bridge_by_addr_port_digest(tor_addr_t
*addr
, uint16_t port
,
4338 SMARTLIST_FOREACH_BEGIN(bridge_list
, bridge_info_t
*, bridge
)
4340 if (tor_digest_is_zero(bridge
->identity
) &&
4341 !tor_addr_compare(&bridge
->addr
, addr
, CMP_EXACT
) &&
4342 bridge
->port
== port
)
4344 if (!memcmp(bridge
->identity
, digest
, DIGEST_LEN
))
4347 SMARTLIST_FOREACH_END(bridge
);
4351 /** Wrapper around get_configured_bridge_by_addr_port_digest() to look
4352 * it up via router descriptor <b>ri</b>. */
4353 static bridge_info_t
*
4354 get_configured_bridge_by_routerinfo(routerinfo_t
*ri
)
4357 tor_addr_from_ipv4h(&addr
, ri
->addr
);
4358 return get_configured_bridge_by_addr_port_digest(&addr
,
4359 ri
->or_port
, ri
->cache_info
.identity_digest
);
4362 /** Return 1 if <b>ri</b> is one of our known bridges, else 0. */
4364 routerinfo_is_a_configured_bridge(routerinfo_t
*ri
)
4366 return get_configured_bridge_by_routerinfo(ri
) ? 1 : 0;
4369 /** We made a connection to a router at <b>addr</b>:<b>port</b>
4370 * without knowing its digest. Its digest turned out to be <b>digest</b>.
4371 * If it was a bridge, and we still don't know its digest, record it.
4374 learned_router_identity(tor_addr_t
*addr
, uint16_t port
, const char *digest
)
4376 bridge_info_t
*bridge
=
4377 get_configured_bridge_by_addr_port_digest(addr
, port
, digest
);
4378 if (bridge
&& tor_digest_is_zero(bridge
->identity
)) {
4379 memcpy(bridge
->identity
, digest
, DIGEST_LEN
);
4380 log_notice(LD_DIR
, "Learned fingerprint %s for bridge %s:%d",
4381 hex_str(digest
, DIGEST_LEN
), fmt_addr(addr
), port
);
4385 /** Remember a new bridge at <b>addr</b>:<b>port</b>. If <b>digest</b>
4386 * is set, it tells us the identity key too. */
4388 bridge_add_from_config(const tor_addr_t
*addr
, uint16_t port
, char *digest
)
4390 bridge_info_t
*b
= tor_malloc_zero(sizeof(bridge_info_t
));
4391 tor_addr_copy(&b
->addr
, addr
);
4394 memcpy(b
->identity
, digest
, DIGEST_LEN
);
4395 b
->fetch_status
.schedule
= DL_SCHED_BRIDGE
;
4397 bridge_list
= smartlist_create();
4398 smartlist_add(bridge_list
, b
);
4401 /** If <b>digest</b> is one of our known bridges, return it. */
4402 static bridge_info_t
*
4403 find_bridge_by_digest(const char *digest
)
4405 SMARTLIST_FOREACH(bridge_list
, bridge_info_t
*, bridge
,
4407 if (!memcmp(bridge
->identity
, digest
, DIGEST_LEN
))
4413 /** We need to ask <b>bridge</b> for its server descriptor. <b>address</b>
4414 * is a helpful string describing this bridge. */
4416 launch_direct_bridge_descriptor_fetch(bridge_info_t
*bridge
)
4420 if (connection_get_by_type_addr_port_purpose(
4421 CONN_TYPE_DIR
, &bridge
->addr
, bridge
->port
,
4422 DIR_PURPOSE_FETCH_SERVERDESC
))
4423 return; /* it's already on the way */
4425 address
= tor_dup_addr(&bridge
->addr
);
4426 directory_initiate_command(address
, &bridge
->addr
,
4428 0, /* does not matter */
4429 1, bridge
->identity
,
4430 DIR_PURPOSE_FETCH_SERVERDESC
,
4431 ROUTER_PURPOSE_BRIDGE
,
4432 0, "authority.z", NULL
, 0, 0);
4436 /** Fetching the bridge descriptor from the bridge authority returned a
4437 * "not found". Fall back to trying a direct fetch. */
4439 retry_bridge_descriptor_fetch_directly(const char *digest
)
4441 bridge_info_t
*bridge
= find_bridge_by_digest(digest
);
4443 return; /* not found? oh well. */
4445 launch_direct_bridge_descriptor_fetch(bridge
);
4448 /** For each bridge in our list for which we don't currently have a
4449 * descriptor, fetch a new copy of its descriptor -- either directly
4450 * from the bridge or via a bridge authority. */
4452 fetch_bridge_descriptors(time_t now
)
4454 or_options_t
*options
= get_options();
4455 int num_bridge_auths
= get_n_authorities(BRIDGE_AUTHORITY
);
4456 int ask_bridge_directly
;
4457 int can_use_bridge_authority
;
4462 SMARTLIST_FOREACH_BEGIN(bridge_list
, bridge_info_t
*, bridge
)
4464 if (!download_status_is_ready(&bridge
->fetch_status
, now
,
4465 IMPOSSIBLE_TO_DOWNLOAD
))
4466 continue; /* don't bother, no need to retry yet */
4468 /* schedule another fetch as if this one will fail, in case it does */
4469 download_status_failed(&bridge
->fetch_status
, 0);
4471 can_use_bridge_authority
= !tor_digest_is_zero(bridge
->identity
) &&
4473 ask_bridge_directly
= !can_use_bridge_authority
||
4474 !options
->UpdateBridgesFromAuthority
;
4475 log_debug(LD_DIR
, "ask_bridge_directly=%d (%d, %d, %d)",
4476 ask_bridge_directly
, tor_digest_is_zero(bridge
->identity
),
4477 !options
->UpdateBridgesFromAuthority
, !num_bridge_auths
);
4479 if (ask_bridge_directly
&&
4480 !fascist_firewall_allows_address_or(&bridge
->addr
, bridge
->port
)) {
4481 log_notice(LD_DIR
, "Bridge at '%s:%d' isn't reachable by our "
4482 "firewall policy. %s.", fmt_addr(&bridge
->addr
),
4484 can_use_bridge_authority
?
4485 "Asking bridge authority instead" : "Skipping");
4486 if (can_use_bridge_authority
)
4487 ask_bridge_directly
= 0;
4492 if (ask_bridge_directly
) {
4493 /* we need to ask the bridge itself for its descriptor. */
4494 launch_direct_bridge_descriptor_fetch(bridge
);
4496 /* We have a digest and we want to ask an authority. We could
4497 * combine all the requests into one, but that may give more
4498 * hints to the bridge authority than we want to give. */
4499 char resource
[10 + HEX_DIGEST_LEN
];
4500 memcpy(resource
, "fp/", 3);
4501 base16_encode(resource
+3, HEX_DIGEST_LEN
+1,
4502 bridge
->identity
, DIGEST_LEN
);
4503 memcpy(resource
+3+HEX_DIGEST_LEN
, ".z", 3);
4504 log_info(LD_DIR
, "Fetching bridge info '%s' from bridge authority.",
4506 directory_get_from_dirserver(DIR_PURPOSE_FETCH_SERVERDESC
,
4507 ROUTER_PURPOSE_BRIDGE
, resource
, 0);
4510 SMARTLIST_FOREACH_END(bridge
);
4513 /** We just learned a descriptor for a bridge. See if that
4514 * digest is in our entry guard list, and add it if not. */
4516 learned_bridge_descriptor(routerinfo_t
*ri
, int from_cache
)
4519 tor_assert(ri
->purpose
== ROUTER_PURPOSE_BRIDGE
);
4520 if (get_options()->UseBridges
) {
4521 int first
= !any_bridge_descriptors_known();
4522 bridge_info_t
*bridge
= get_configured_bridge_by_routerinfo(ri
);
4523 time_t now
= time(NULL
);
4526 if (bridge
) { /* if we actually want to use this one */
4527 /* it's here; schedule its re-fetch for a long time from now. */
4529 download_status_reset(&bridge
->fetch_status
);
4531 add_an_entry_guard(ri
, 1);
4532 log_notice(LD_DIR
, "new bridge descriptor '%s' (%s)", ri
->nickname
,
4533 from_cache
? "cached" : "fresh");
4535 routerlist_retry_directory_downloads(now
);
4540 /** Return 1 if any of our entry guards have descriptors that
4541 * are marked with purpose 'bridge' and are running. Else return 0.
4543 * We use this function to decide if we're ready to start building
4544 * circuits through our bridges, or if we need to wait until the
4545 * directory "server/authority" requests finish. */
4547 any_bridge_descriptors_known(void)
4549 tor_assert(get_options()->UseBridges
);
4550 return choose_random_entry(NULL
)!=NULL
? 1 : 0;
4553 /** Return 1 if there are any directory conns fetching bridge descriptors
4554 * that aren't marked for close. We use this to guess if we should tell
4555 * the controller that we have a problem. */
4557 any_pending_bridge_descriptor_fetches(void)
4559 smartlist_t
*conns
= get_connection_array();
4560 SMARTLIST_FOREACH(conns
, connection_t
*, conn
,
4562 if (conn
->type
== CONN_TYPE_DIR
&&
4563 conn
->purpose
== DIR_PURPOSE_FETCH_SERVERDESC
&&
4564 TO_DIR_CONN(conn
)->router_purpose
== ROUTER_PURPOSE_BRIDGE
&&
4565 !conn
->marked_for_close
&&
4566 conn
->linked
&& !conn
->linked_conn
->marked_for_close
) {
4567 log_debug(LD_DIR
, "found one: %s", conn
->address
);
4574 /** Return 1 if we have at least one descriptor for a bridge and
4575 * all descriptors we know are down. Else return 0. If <b>act</b> is
4576 * 1, then mark the down bridges up; else just observe and report. */
4578 bridges_retry_helper(int act
)
4582 int any_running
= 0;
4584 entry_guards
= smartlist_create();
4585 SMARTLIST_FOREACH(entry_guards
, entry_guard_t
*, e
,
4587 ri
= router_get_by_digest(e
->identity
);
4588 if (ri
&& ri
->purpose
== ROUTER_PURPOSE_BRIDGE
) {
4591 any_running
= 1; /* some bridge is both known and running */
4592 else if (act
) { /* mark it for retry */
4599 log_debug(LD_DIR
, "any_known %d, any_running %d", any_known
, any_running
);
4600 return any_known
&& !any_running
;
4603 /** Do we know any descriptors for our bridges, and are they all
4606 bridges_known_but_down(void)
4608 return bridges_retry_helper(0);
4611 /** Mark all down known bridges up. */
4613 bridges_retry_all(void)
4615 bridges_retry_helper(1);
4618 /** Release all storage held by the list of entry guards and related
4619 * memory structs. */
4621 entry_guards_free_all(void)
4624 SMARTLIST_FOREACH(entry_guards
, entry_guard_t
*, e
,
4625 entry_guard_free(e
));
4626 smartlist_free(entry_guards
);
4627 entry_guards
= NULL
;
4629 clear_bridge_list();
4630 smartlist_free(bridge_list
);