src/feature/control/btrack_orconn.c

   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"
  43 #include "core/or/orconn_event.h"
  44 #include "feature/control/btrack_orconn.h"
  45 #include "feature/control/btrack_orconn_cevent.h"
  46 #include "feature/control/btrack_orconn_maps.h"
  47 #include "lib/log/log.h"
  48 #include "lib/pubsub/pubsub.h"
  49
  50 DECLARE_SUBSCRIBE(orconn_state, bto_state_rcvr);
  51 DECLARE_SUBSCRIBE(orconn_status, bto_status_rcvr);
  52 DECLARE_SUBSCRIBE(ocirc_chan, bto_chan_rcvr);
  53
  54 /** Pair of a best ORCONN GID and with its state */
  55 typedef struct bto_best_t {
  56   uint64_t gid;
  57   int state;
  58 } bto_best_t;
  59
  60 /** GID and state of the best ORCONN we've seen so far */
  61 static bto_best_t best_any = { 0, -1 };
  62 /** GID and state of the best application circuit ORCONN we've seen so far */
  63 static 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  **/
  70 static bool
  71 bto_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  **/
  94 static void
  95 bto_update_bests(const bt_orconn_t *bto)
  96 {
  97   tor_assert(bto->is_orig);
  98
  99   if (bto_update_best(bto, &best_any, "ANY"))
 100     bto_cevent_anyconn(bto);
 101   if (!bto->is_onehop && bto_update_best(bto, &best_ap, "AP"))
 102     bto_cevent_apconn(bto);
 103 }
 104
 105 /** Reset cached "best" values */
 106 static void
 107 bto_reset_bests(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  **/
 117 static void
 118 bto_state_rcvr(const msg_t *msg, const orconn_state_msg_t *arg)
 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  **/
 138 static void
 139 bto_status_rcvr(const msg_t *msg, const orconn_status_msg_t *arg)
 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  **/
 158 static void
 159 bto_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  **/
 179 int
 180 btrack_orconn_init(void)
 181 {
 182   bto_init_maps();
 183
 184   return 0;
 185 }
 186
 187 int
 188 btrack_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 */
 200 void
 201 btrack_orconn_fini(void)
 202 {
 203   bto_clear_maps();
 204   bto_reset_bests();
 205   bto_cevent_reset();
 206 }