Tor  0.4.3.0-alpha-dev
circuitstats.h
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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) 2007-2019, The Tor Project, Inc. */
5 /* See LICENSE for licensing information */
6 
7 /**
8  * \file circuitstats.h
9  * \brief Header file for circuitstats.c
10  **/
11 
12 #ifndef TOR_CIRCUITSTATS_H
13 #define TOR_CIRCUITSTATS_H
14 
15 const circuit_build_times_t *get_circuit_build_times(void);
16 circuit_build_times_t *get_circuit_build_times_mutable(void);
18 double get_circuit_build_timeout_ms(void);
19 
20 int circuit_build_times_disabled(const or_options_t *options);
22  int ignore_consensus);
23 
24 /** A build_time_t is milliseconds */
25 typedef uint32_t build_time_t;
26 
27 int circuit_build_times_enough_to_compute(const circuit_build_times_t *cbt);
28 void circuit_build_times_update_state(const circuit_build_times_t *cbt,
29  or_state_t *state);
30 int circuit_build_times_parse_state(circuit_build_times_t *cbt,
31  or_state_t *state);
32 void circuit_build_times_count_timeout(circuit_build_times_t *cbt,
33  int did_onehop);
34 int circuit_build_times_count_close(circuit_build_times_t *cbt,
35  int did_onehop, time_t start_time);
36 void circuit_build_times_set_timeout(circuit_build_times_t *cbt);
37 int circuit_build_times_add_time(circuit_build_times_t *cbt,
38  build_time_t time);
39 int circuit_build_times_needs_circuits(const circuit_build_times_t *cbt);
41 
42 int circuit_build_times_needs_circuits_now(const circuit_build_times_t *cbt);
43 void circuit_build_times_init(circuit_build_times_t *cbt);
44 void circuit_build_times_free_timeouts(circuit_build_times_t *cbt);
45 void circuit_build_times_new_consensus_params(circuit_build_times_t *cbt,
46  networkstatus_t *ns);
47 double circuit_build_times_timeout_rate(const circuit_build_times_t *cbt);
48 double circuit_build_times_close_rate(const circuit_build_times_t *cbt);
49 
50 void circuit_build_times_update_last_circ(circuit_build_times_t *cbt);
52 
53 /** Total size of the circuit timeout history to accumulate.
54  * 1000 is approx 2.5 days worth of continual-use circuits. */
55 #define CBT_NCIRCUITS_TO_OBSERVE 1000
56 
57 /** Width of the histogram bins in milliseconds */
58 #define CBT_BIN_WIDTH ((build_time_t)50)
59 
60 /** Number of modes to use in the weighted-avg computation of Xm */
61 #define CBT_DEFAULT_NUM_XM_MODES 3
62 #define CBT_MIN_NUM_XM_MODES 1
63 #define CBT_MAX_NUM_XM_MODES 20
64 
65 /**
66  * CBT_BUILD_ABANDONED is our flag value to represent a force-closed
67  * circuit (Aka a 'right-censored' pareto value).
68  */
69 #define CBT_BUILD_ABANDONED ((build_time_t)(INT32_MAX-1))
70 #define CBT_BUILD_TIME_MAX ((build_time_t)(INT32_MAX))
71 
72 /** Save state every 10 circuits */
73 #define CBT_SAVE_STATE_EVERY 10
74 
75 /* Circuit build times consensus parameters */
76 
77 /**
78  * How long to wait before actually closing circuits that take too long to
79  * build in terms of CDF quantile.
80  */
81 #define CBT_DEFAULT_CLOSE_QUANTILE 95
82 #define CBT_MIN_CLOSE_QUANTILE CBT_MIN_QUANTILE_CUTOFF
83 #define CBT_MAX_CLOSE_QUANTILE CBT_MAX_QUANTILE_CUTOFF
84 
85 /**
86  * How many circuits count as recent when considering if the
87  * connection has gone gimpy or changed.
88  */
89 #define CBT_DEFAULT_RECENT_CIRCUITS 20
90 #define CBT_MIN_RECENT_CIRCUITS 3
91 #define CBT_MAX_RECENT_CIRCUITS 1000
92 
93 /**
94  * Maximum count of timeouts that finish the first hop in the past
95  * RECENT_CIRCUITS before calculating a new timeout.
96  *
97  * This tells us whether to abandon timeout history and set
98  * the timeout back to whatever circuit_build_times_get_initial_timeout()
99  * gives us.
100  */
101 #define CBT_DEFAULT_MAX_RECENT_TIMEOUT_COUNT (CBT_DEFAULT_RECENT_CIRCUITS*9/10)
102 #define CBT_MIN_MAX_RECENT_TIMEOUT_COUNT 3
103 #define CBT_MAX_MAX_RECENT_TIMEOUT_COUNT 10000
104 
105 /** Minimum circuits before estimating a timeout */
106 #define CBT_DEFAULT_MIN_CIRCUITS_TO_OBSERVE 100
107 #define CBT_MIN_MIN_CIRCUITS_TO_OBSERVE 1
108 #define CBT_MAX_MIN_CIRCUITS_TO_OBSERVE 10000
109 
110 /** Cutoff percentile on the CDF for our timeout estimation. */
111 #define CBT_DEFAULT_QUANTILE_CUTOFF 80
112 #define CBT_MIN_QUANTILE_CUTOFF 10
113 #define CBT_MAX_QUANTILE_CUTOFF 99
115 
116 /** How often in seconds should we build a test circuit */
117 #define CBT_DEFAULT_TEST_FREQUENCY 10
118 #define CBT_MIN_TEST_FREQUENCY 1
119 #define CBT_MAX_TEST_FREQUENCY INT32_MAX
120 
121 /** Lowest allowable value for CircuitBuildTimeout in milliseconds */
122 #define CBT_DEFAULT_TIMEOUT_MIN_VALUE (1500)
123 #define CBT_MIN_TIMEOUT_MIN_VALUE 500
124 #define CBT_MAX_TIMEOUT_MIN_VALUE INT32_MAX
125 
126 /** Initial circuit build timeout in milliseconds */
127 #define CBT_DEFAULT_TIMEOUT_INITIAL_VALUE (60*1000)
128 #define CBT_MIN_TIMEOUT_INITIAL_VALUE CBT_MIN_TIMEOUT_MIN_VALUE
129 #define CBT_MAX_TIMEOUT_INITIAL_VALUE INT32_MAX
131 
132 #if CBT_DEFAULT_MAX_RECENT_TIMEOUT_COUNT < CBT_MIN_MAX_RECENT_TIMEOUT_COUNT
133 #error "RECENT_CIRCUITS is set too low."
134 #endif
135 
136 #ifdef CIRCUITSTATS_PRIVATE
137 STATIC double circuit_build_times_calculate_timeout(circuit_build_times_t *cbt,
138  double quantile);
139 STATIC int circuit_build_times_update_alpha(circuit_build_times_t *cbt);
140 STATIC void circuit_build_times_reset(circuit_build_times_t *cbt);
141 
142 /* Network liveness functions */
144  circuit_build_times_t *cbt);
145 #endif /* defined(CIRCUITSTATS_PRIVATE) */
146 
147 #ifdef TOR_UNIT_TESTS
148 build_time_t circuit_build_times_generate_sample(circuit_build_times_t *cbt,
149  double q_lo, double q_hi);
150 double circuit_build_times_cdf(circuit_build_times_t *cbt, double x);
151 void circuit_build_times_initial_alpha(circuit_build_times_t *cbt,
152  double quantile, double time_ms);
153 void circuitbuild_running_unit_tests(void);
154 #endif /* defined(TOR_UNIT_TESTS) */
155 
156 /* Network liveness functions */
157 void circuit_build_times_network_is_live(circuit_build_times_t *cbt);
158 int circuit_build_times_network_check_live(const circuit_build_times_t *cbt);
159 void circuit_build_times_network_circ_success(circuit_build_times_t *cbt);
160 
161 #ifdef CIRCUITSTATS_PRIVATE
162 /** Information about the state of our local network connection */
163 typedef struct {
164  /** The timestamp we last completed a TLS handshake or received a cell */
165  time_t network_last_live;
166  /** If the network is not live, how many timeouts has this caused? */
167  int nonlive_timeouts;
168  /** Circular array of circuits that have made it to the first hop. Slot is
169  * 1 if circuit timed out, 0 if circuit succeeded */
170  int8_t *timeouts_after_firsthop;
171  /** Number of elements allocated for the above array */
172  int num_recent_circs;
173  /** Index into circular array. */
174  int after_firsthop_idx;
175 } network_liveness_t;
176 
177 /** Structure for circuit build times history */
178 struct circuit_build_times_s {
179  /** The circular array of recorded build times in milliseconds */
180  build_time_t circuit_build_times[CBT_NCIRCUITS_TO_OBSERVE];
181  /** Current index in the circuit_build_times circular array */
182  int build_times_idx;
183  /** Total number of build times accumulated. Max CBT_NCIRCUITS_TO_OBSERVE */
184  int total_build_times;
185  /** Information about the state of our local network connection */
186  network_liveness_t liveness;
187  /** Last time we built a circuit. Used to decide to build new test circs */
188  time_t last_circ_at;
189  /** "Minimum" value of our pareto distribution (actually mode) */
190  build_time_t Xm;
191  /** alpha exponent for pareto dist. */
192  double alpha;
193  /** Have we computed a timeout? */
194  int have_computed_timeout;
195  /** The exact value for that timeout in milliseconds. Stored as a double
196  * to maintain precision from calculations to and from quantile value. */
197  double timeout_ms;
198  /** How long we wait before actually closing the circuit. */
199  double close_ms;
200  /** Total succeeded counts. Old measurements may be scaled downward if
201  * we've seen a lot of circuits. */
202  uint32_t num_circ_succeeded;
203  /** Total timeout counts. Old measurements may be scaled downward if
204  * we've seen a lot of circuits. */
205  uint32_t num_circ_timeouts;
206  /** Total closed counts. Old measurements may be scaled downward if
207  * we've seen a lot of circuits.*/
208  uint32_t num_circ_closed;
209 
210 };
211 #endif /* defined(CIRCUITSTATS_PRIVATE) */
212 
213 #endif /* !defined(TOR_CIRCUITSTATS_H) */
int32_t circuit_build_times_initial_timeout(void)
Definition: circuitstats.c:374
void circuit_build_times_set_timeout(circuit_build_times_t *cbt)
void circuit_build_times_free_timeouts(circuit_build_times_t *cbt)
Definition: circuitstats.c:595
uint32_t build_time_t
Definition: circuitstats.h:25
int circuit_build_times_count_close(circuit_build_times_t *cbt, int did_onehop, time_t start_time)
void circuit_build_times_init(circuit_build_times_t *cbt)
Definition: circuitstats.c:569
double circuit_build_times_close_rate(const circuit_build_times_t *cbt)
const circuit_build_times_t * get_circuit_build_times(void)
Definition: circuitstats.c:82
double circuit_build_times_timeout_rate(const circuit_build_times_t *cbt)
void circuit_build_times_new_consensus_params(circuit_build_times_t *cbt, networkstatus_t *ns)
Definition: circuitstats.c:430
STATIC double circuit_build_times_calculate_timeout(circuit_build_times_t *cbt, double quantile)
double get_circuit_build_close_time_ms(void)
Definition: circuitstats.c:97
double circuit_build_times_quantile_cutoff(void)
Definition: circuitstats.c:271
#define STATIC
Definition: testsupport.h:32
STATIC int circuit_build_times_network_check_changed(circuit_build_times_t *cbt)
int circuit_build_times_parse_state(circuit_build_times_t *cbt, or_state_t *state)
void circuit_build_times_count_timeout(circuit_build_times_t *cbt, int did_onehop)
#define CBT_NCIRCUITS_TO_OBSERVE
Definition: circuitstats.h:55
int circuit_build_times_disabled(const or_options_t *options)
Definition: circuitstats.c:121
void circuit_build_times_network_circ_success(circuit_build_times_t *cbt)
void circuit_build_times_mark_circ_as_measurement_only(origin_circuit_t *circ)
Definition: circuitstats.c:641
int circuit_build_times_disabled_(const or_options_t *options, int ignore_consensus)
Definition: circuitstats.c:128
circuit_build_times_t * get_circuit_build_times_mutable(void)
Definition: circuitstats.c:89
int circuit_build_times_enough_to_compute(const circuit_build_times_t *cbt)
Definition: circuitstats.c:259
int circuit_build_times_network_check_live(const circuit_build_times_t *cbt)
double get_circuit_build_timeout_ms(void)
Definition: circuitstats.c:105
int circuit_build_times_add_time(circuit_build_times_t *cbt, build_time_t time)
Definition: circuitstats.c:760
void circuit_build_times_update_state(const circuit_build_times_t *cbt, or_state_t *state)
Definition: circuitstats.c:932
STATIC void circuit_build_times_reset(circuit_build_times_t *cbt)
Definition: circuitstats.c:549
int circuit_build_times_needs_circuits(const circuit_build_times_t *cbt)
STATIC int circuit_build_times_update_alpha(circuit_build_times_t *cbt)
void circuit_build_times_handle_completed_hop(origin_circuit_t *circ)
Definition: circuitstats.c:683
int circuit_build_times_needs_circuits_now(const circuit_build_times_t *cbt)
void circuit_build_times_network_is_live(circuit_build_times_t *cbt)