Tor 0.4.9.1-alpha-dev
btrack_orconn.c
Go to the documentation of this file.
1/* Copyright (c) 2007-2021, The Tor Project, Inc. */
2/* See LICENSE for licensing information */
3
4/**
5 * \file btrack_orconn.c
6 * \brief Bootstrap tracker for OR connections
7 *
8 * Track state changes of OR connections, as published by the
9 * connection subsystem. Also track circuit launch events, because
10 * they're one of the few ways to discover the association between a
11 * channel (and OR connection) and a circuit.
12 *
13 * We track all OR connections that we receive events for, whether or
14 * not they're carrying origin circuits. (An OR connection might
15 * carry origin circuits only after we first find out about that
16 * connection.)
17 *
18 * All origin ORCONN events update the "any" state variables, while
19 * only application ORCONN events update the "ap" state variables (and
20 * also update the "any") variables.
21 *
22 * We do this because we want to report the first increments of
23 * connection progress as the earliest bootstrap phases. This results
24 * in a better user experience because failures here translate into
25 * zero or very small amounts of displayed progress, instead of
26 * progress stuck near completion. The first connection to a relay
27 * might be a one-hop circuit for directory lookups, or it might be a
28 * connection for an application circuit because we already have
29 * enough directory info to build an application circuit.
30 *
31 * We call functions in btrack_orconn_cevent.c to generate the actual
32 * controller events, because some of the state decoding we need to do
33 * is complicated.
34 **/
35
36#include <stdbool.h>
37
38#include "core/or/or.h"
39
40#define BTRACK_ORCONN_PRIVATE
41
42#include "core/or/ocirc_event.h"
47#include "lib/log/log.h"
48#include "lib/pubsub/pubsub.h"
49
53
54/** Pair of a best ORCONN GID and with its state */
55typedef struct bto_best_t {
56 uint64_t gid;
57 int state;
59
60/** GID and state of the best ORCONN we've seen so far */
61static bto_best_t best_any = { 0, -1 };
62/** GID and state of the best application circuit ORCONN we've seen so far */
63static bto_best_t best_ap = { 0, -1 };
64
65/**
66 * Update a cached state of a best ORCONN progress we've seen so far.
67 *
68 * Return true if the new state is better than the old.
69 **/
70static bool
71bto_update_best(const bt_orconn_t *bto, bto_best_t *best, const char *type)
72{
73 if (bto->state < best->state)
74 return false;
75 /* Update even if we won't change best->state, because it's more
76 * recent information that a particular connection transitioned to
77 * that state. */
78 best->gid = bto->gid;
79 if (bto->state > best->state) {
80 log_info(LD_BTRACK, "ORCONN BEST_%s state %d->%d gid=%"PRIu64, type,
81 best->state, bto->state, bto->gid);
82 best->state = bto->state;
83 return true;
84 }
85 return false;
86}
87
88/**
89 * Update cached states of best ORCONN progress we've seen
90 *
91 * Only update the application ORCONN state if we know it's carrying
92 * an application circuit.
93 **/
94static void
95bto_update_bests(const bt_orconn_t *bto)
96{
97 tor_assert(bto->is_orig);
98
99 if (bto_update_best(bto, &best_any, "ANY"))
101 if (!bto->is_onehop && bto_update_best(bto, &best_ap, "AP"))
103}
104
105/** Reset cached "best" values */
106static void
108{
109 best_any.gid = best_ap.gid = 0;
110 best_any.state = best_ap.state = -1;
111}
112
113/**
114 * Update cached states of ORCONNs from the incoming message. This
115 * message comes from code in connection_or.c.
116 **/
117static void
119{
120 bt_orconn_t *bto;
121
122 (void)msg;
123 bto = bto_find_or_new(arg->gid, arg->chan);
124 log_debug(LD_BTRACK, "ORCONN gid=%"PRIu64" chan=%"PRIu64
125 " proxy_type=%d state=%d",
126 arg->gid, arg->chan, arg->proxy_type, arg->state);
127 bto->proxy_type = arg->proxy_type;
128 bto->state = arg->state;
129 if (bto->is_orig)
130 bto_update_bests(bto);
131}
132
133/**
134 * Delete a cached ORCONN state if we get an incoming message saying
135 * the ORCONN is failed or closed. This message comes from code in
136 * control.c.
137 **/
138static void
140{
141 (void)msg;
142 switch (arg->status) {
143 case OR_CONN_EVENT_FAILED:
144 case OR_CONN_EVENT_CLOSED:
145 log_info(LD_BTRACK, "ORCONN DELETE gid=%"PRIu64" status=%d reason=%d",
146 arg->gid, arg->status, arg->reason);
147 return bto_delete(arg->gid);
148 default:
149 break;
150 }
151}
152
153/**
154 * Create or update a cached ORCONN state for a newly launched
155 * connection, including whether it's launched by an origin circuit
156 * and whether it's a one-hop circuit.
157 **/
158static void
159bto_chan_rcvr(const msg_t *msg, const ocirc_chan_msg_t *arg)
160{
161 bt_orconn_t *bto;
162
163 (void)msg;
164 bto = bto_find_or_new(0, arg->chan);
165 if (!bto->is_orig || (bto->is_onehop && !arg->onehop)) {
166 log_debug(LD_BTRACK, "ORCONN LAUNCH chan=%"PRIu64" onehop=%d",
167 arg->chan, arg->onehop);
168 }
169 bto->is_orig = true;
170 if (!arg->onehop)
171 bto->is_onehop = false;
172 bto_update_bests(bto);
173}
174
175/**
176 * Initialize the hash maps and subscribe to ORCONN and origin
177 * circuit events.
178 **/
179int
181{
183
184 return 0;
185}
186
187int
188btrack_orconn_add_pubsub(pubsub_connector_t *connector)
189{
190 if (DISPATCH_ADD_SUB(connector, orconn, orconn_state))
191 return -1;
192 if (DISPATCH_ADD_SUB(connector, orconn, orconn_status))
193 return -1;
194 if (DISPATCH_ADD_SUB(connector, ocirc, ocirc_chan))
195 return -1;
196 return 0;
197}
198
199/** Clear the hash maps and reset the "best" states */
200void
202{
206}
static bool bto_update_best(const bt_orconn_t *bto, bto_best_t *best, const char *type)
Definition: btrack_orconn.c:71
int btrack_orconn_init(void)
static bto_best_t best_any
Definition: btrack_orconn.c:61
static void bto_chan_rcvr(const msg_t *msg, const ocirc_chan_msg_t *arg)
static void bto_state_rcvr(const msg_t *msg, const orconn_state_msg_t *arg)
static void bto_status_rcvr(const msg_t *msg, const orconn_status_msg_t *arg)
static bto_best_t best_ap
Definition: btrack_orconn.c:63
void btrack_orconn_fini(void)
static void bto_reset_bests(void)
static void bto_update_bests(const bt_orconn_t *bto)
Definition: btrack_orconn.c:95
Header file for btrack_orconn.c.
void bto_cevent_reset(void)
void bto_cevent_anyconn(const bt_orconn_t *bto)
void bto_cevent_apconn(const bt_orconn_t *bto)
Header file for btrack_orconn_cevent.c.
void bto_clear_maps(void)
bt_orconn_t * bto_find_or_new(uint64_t gid, uint64_t chan)
void bto_init_maps(void)
void bto_delete(uint64_t gid)
Header file for btrack_orconn_maps.c.
Headers for log.c.
#define LD_BTRACK
Definition: log.h:119
Header file for ocirc_event.c.
Master header file for Tor-specific functionality.
Header file for orconn_event.c.
Header for OO publish-subscribe functionality.
struct pubsub_connector_t pubsub_connector_t
#define DISPATCH_ADD_SUB(connector, channel, messagename)
#define DECLARE_SUBSCRIBE(messagename, hookfn)
Definition: msgtypes.h:50
#define tor_assert(expr)
Definition: util_bug.h:103