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Diffstat (limited to 'src/feature/control/btrack_circuit.c')
-rw-r--r-- | src/feature/control/btrack_circuit.c | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/src/feature/control/btrack_circuit.c b/src/feature/control/btrack_circuit.c new file mode 100644 index 0000000000..be51b51046 --- /dev/null +++ b/src/feature/control/btrack_circuit.c @@ -0,0 +1,166 @@ +/* Copyright (c) 2007-2020, The Tor Project, Inc. */ +/* See LICENSE for licensing information */ + +/** + * \file btrack_circuit.c + * \brief Bootstrap tracker for origin circuits + * + * Track state changes of origin circuits, as published by the circuit + * subsystem. + **/ + +#include "core/or/or.h" + +#include "core/or/ocirc_event.h" + +#include "feature/control/btrack_circuit.h" +#include "feature/control/control.h" +#include "lib/log/log.h" + +/** Pair of a best origin circuit GID with its state or status */ +typedef struct btc_best_t { + uint32_t gid; + int val; +} btc_best_t; + +/** GID and state of the best origin circuit we've seen so far */ +static btc_best_t best_any_state = { 0, -1 }; +/** GID and state of the best application circuit we've seen so far */ +static btc_best_t best_ap_state = { 0, -1 }; +/** GID and status of the best origin circuit we've seen so far */ +static btc_best_t best_any_evtype = { 0, -1 }; +/** GID and status of the best application circuit we've seen so far */ +static btc_best_t best_ap_evtype = { 0, -1 }; + +/** Reset cached "best" values */ +static void +btc_reset_bests(void) +{ + best_any_state.gid = best_ap_state.gid = 0; + best_any_state.val = best_ap_state.val = -1; + best_any_evtype.gid = best_ap_state.gid = 0; + best_any_evtype.val = best_ap_evtype.val = -1; +} + +/** True if @a state is a "better" origin circuit state than @a best->val */ +static bool +btc_state_better(int state, const btc_best_t *best) +{ + return state > best->val; +} + +/** + * Definine an ordering on circuit status events + * + * The CIRC_EVENT_ constants aren't sorted in a useful order, so this + * array helps to decode them. This approach depends on the statuses + * being nonnegative and dense. + **/ +static int circ_event_order[] = { + [CIRC_EVENT_FAILED] = -1, + [CIRC_EVENT_CLOSED] = -1, + [CIRC_EVENT_LAUNCHED] = 1, + [CIRC_EVENT_EXTENDED] = 2, + [CIRC_EVENT_BUILT] = 3, +}; +#define N_CIRC_EVENT_ORDER \ + (sizeof(circ_event_order) / sizeof(circ_event_order[0])) + +/** True if @a state is a "better" origin circuit event status than @a + best->val */ +static bool +btc_evtype_better(int state, const btc_best_t *best) +{ + if (state < 0) + return false; + if (best->val < 0) + return true; + + tor_assert(state >= 0 && (unsigned)state < N_CIRC_EVENT_ORDER); + tor_assert(best->val >= 0 && (unsigned)best->val < N_CIRC_EVENT_ORDER); + return circ_event_order[state] > circ_event_order[best->val]; +} + +static bool +btc_update_state(const ocirc_state_msg_t *msg, btc_best_t *best, + const char *type) +{ + if (btc_state_better(msg->state, best)) { + log_info(LD_BTRACK, "CIRC BEST_%s state %d->%d gid=%"PRIu32, type, + best->val, msg->state, msg->gid); + best->gid = msg->gid; + best->val = msg->state; + return true; + } + return false; +} + +static bool +btc_update_evtype(const ocirc_cevent_msg_t *msg, btc_best_t *best, + const char *type) +{ + if (btc_evtype_better(msg->evtype, best)) { + log_info(LD_BTRACK, "CIRC BEST_%s evtype %d->%d gid=%"PRIu32, type, + best->val, msg->evtype, msg->gid); + best->gid = msg->gid; + best->val = msg->evtype; + return true; + } + return false; +} + +DECLARE_SUBSCRIBE(ocirc_state, btc_state_rcvr); +DECLARE_SUBSCRIBE(ocirc_cevent, btc_cevent_rcvr); +DECLARE_SUBSCRIBE(ocirc_chan, btc_chan_rcvr); + +static void +btc_state_rcvr(const msg_t *msg, const ocirc_state_msg_t *arg) +{ + (void)msg; + log_debug(LD_BTRACK, "CIRC gid=%"PRIu32" state=%d onehop=%d", + arg->gid, arg->state, arg->onehop); + + btc_update_state(arg, &best_any_state, "ANY"); + if (arg->onehop) + return; + btc_update_state(arg, &best_ap_state, "AP"); +} + +static void +btc_cevent_rcvr(const msg_t *msg, const ocirc_cevent_msg_t *arg) +{ + (void)msg; + log_debug(LD_BTRACK, "CIRC gid=%"PRIu32" evtype=%d reason=%d onehop=%d", + arg->gid, arg->evtype, arg->reason, arg->onehop); + + btc_update_evtype(arg, &best_any_evtype, "ANY"); + if (arg->onehop) + return; + btc_update_evtype(arg, &best_ap_evtype, "AP"); +} + +static void +btc_chan_rcvr(const msg_t *msg, const ocirc_chan_msg_t *arg) +{ + (void)msg; + log_debug(LD_BTRACK, "CIRC gid=%"PRIu32" chan=%"PRIu64" onehop=%d", + arg->gid, arg->chan, arg->onehop); +} + +int +btrack_circ_add_pubsub(pubsub_connector_t *connector) +{ + if (DISPATCH_ADD_SUB(connector, ocirc, ocirc_chan)) + return -1; + if (DISPATCH_ADD_SUB(connector, ocirc, ocirc_cevent)) + return -1; + if (DISPATCH_ADD_SUB(connector, ocirc, ocirc_state)) + return -1; + return 0; +} + +void +btrack_circ_fini(void) +{ + btc_reset_bests(); +} |