--- /dev/null
+/* Copyright (c) 2023, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file conflux_params.h
+ * \brief Header file for conflux_params.c.
+ **/
+
+#include "core/or/or.h"
+
+#include "app/config/config.h"
+
+#include "core/or/conflux_params.h"
+#include "core/or/congestion_control_common.h"
+#include "core/or/circuitlist.h"
+
+#include "feature/nodelist/networkstatus.h"
+#include "feature/nodelist/networkstatus_st.h"
+#include "feature/nodelist/routerstatus_st.h"
+#include "feature/relay/routermode.h"
+
+#include "core/or/origin_circuit_st.h"
+
+/**
+ * Consensus parameters defaults, minimums and maximums.
+ */
+
+/* For "cfx_enabled". */
+#define CONFLUX_ENABLED_MIN (0)
+#define CONFLUX_ENABLED_MAX (1)
+#define CONFLUX_ENABLED_DEFAULT (1)
+
+/* For "cfx_low_exit_threshold". This is a percentage scaled to 10000 so we can
+ * support two decimal points. For example, 65.78% would be 6578. */
+#define LOW_EXIT_THRESHOLD_MIN (0)
+#define LOW_EXIT_THRESHOLD_MAX (10000)
+#define LOW_EXIT_THRESHOLD_DEFAULT (6000)
+
+/* For "cfx_max_linked_set". */
+#define MAX_LINKED_SET_MIN (0)
+#define MAX_LINKED_SET_MAX (UINT8_MAX)
+#define MAX_LINKED_SET_DEFAULT (10)
+
+/* For "cfx_max_prebuilt_set". */
+#define MAX_PREBUILT_SET_MIN (0)
+#define MAX_PREBUILT_SET_MAX (UINT8_MAX)
+#define MAX_PREBUILT_SET_DEFAULT (3)
+
+/* For "cfx_max_leg_retry". */
+#define MAX_UNLINKED_LEG_RETRY_DEFAULT (3)
+#define MAX_UNLINKED_LEG_RETRY_MIN (0)
+#define MAX_UNLINKED_LEG_RETRY_MAX (UINT8_MAX)
+
+/* For "cfx_num_legs_set". */
+#define NUM_LEGS_SET_MIN (0)
+#define NUM_LEGS_SET_MAX (UINT8_MAX)
+#define NUM_LEGS_SET_DEFAULT (2)
+
+/* For "cfx_send_pct". */
+#define CFX_SEND_PCT_MIN (0)
+#define CFX_SEND_PCT_MAX (255)
+#define CFX_SEND_PCT_DFLT 100
+
+/* For "cfx_drain_pct". */
+#define CFX_DRAIN_PCT_MIN (0)
+#define CFX_DRAIN_PCT_MAX (255)
+#define CFX_DRAIN_PCT_DFLT 0
+
+/*
+ * Cached consensus parameters.
+ */
+
+/* Indicate if conflux is enabled or disabled. */
+static bool conflux_enabled = CONFLUX_ENABLED_DEFAULT;
+/* Maximum number of linked set we are allowed to have (even if in use). */
+static uint8_t max_linked_set = MAX_LINKED_SET_DEFAULT;
+/* Maximum number of pre built set. */
+static uint8_t max_prebuilt_set = MAX_PREBUILT_SET_DEFAULT;
+/* Maximum number of unlinked leg retry that is how many times are we allowed
+ * to retry a leg until it successfully links. */
+STATIC uint32_t max_unlinked_leg_retry = MAX_UNLINKED_LEG_RETRY_DEFAULT;
+/* Number of legs per set. */
+static uint8_t num_legs_set = NUM_LEGS_SET_DEFAULT;
+/* The low Exit relay threshold, as a ratio between 0 and 1, used as a limit to
+ * decide the amount of pre-built set we build depending on how many Exit relay
+ * supports conflux in our current consensus. */
+static double low_exit_threshold_ratio =
+ LOW_EXIT_THRESHOLD_DEFAULT / (double)LOW_EXIT_THRESHOLD_MAX;
+
+static uint8_t cfx_drain_pct = CFX_DRAIN_PCT_DFLT;
+static uint8_t cfx_send_pct = CFX_SEND_PCT_DFLT;
+
+/* Ratio of Exit relays in our consensus supporting conflux. This is computed
+ * at every consensus and it is between 0 and 1. */
+static double exit_conflux_ratio = 0.0;
+
+/** Sets num_conflux_exit with the latest count of Exits in the given consensus
+ * that supports Conflux. */
+static void
+count_exit_with_conflux_support(const networkstatus_t *ns)
+{
+ double supported = 0.0;
+
+ if (!ns || smartlist_len(ns->routerstatus_list) == 0) {
+ return;
+ }
+
+ SMARTLIST_FOREACH_BEGIN(ns->routerstatus_list, const routerstatus_t *, rs) {
+ if (rs->pv.supports_conflux) {
+ supported++;
+ }
+ } SMARTLIST_FOREACH_END(rs);
+
+ exit_conflux_ratio =
+ supported / smartlist_len(ns->routerstatus_list);
+
+ log_info(LD_GENERAL, "Consensus has %.2f %% Exit relays supporting Conflux",
+ exit_conflux_ratio * 100.0);
+}
+
+/**
+ * Return true iff conflux feature is enabled and usable for a given circuit.
+ *
+ * Circ may be NULL, in which case we only check the consensus and torrc. */
+bool
+conflux_is_enabled(const circuit_t *circ)
+{
+ const or_options_t *opts = get_options();
+
+ /* Conflux CAN NOT operate properly without congestion control and so
+ * automatically disabled conflux if we don't have CC enabled. */
+ if (!congestion_control_enabled()) {
+ return false;
+ }
+
+ if (circ) {
+ /* If circuit is non-null, we need to check to see if congestion
+ * control was successfully negotiated. Conflux depends upon congestion
+ * control, and consensus checks are not enough because there can be a
+ * race between those checks and the consensus update to enable
+ * congestion control. This happens in Shadow, and at relay restart. */
+ if (CIRCUIT_IS_ORIGIN(circ)) {
+ tor_assert(CONST_TO_ORIGIN_CIRCUIT(circ)->cpath);
+ tor_assert(CONST_TO_ORIGIN_CIRCUIT(circ)->cpath->prev);
+ if (!CONST_TO_ORIGIN_CIRCUIT(circ)->cpath->prev->ccontrol)
+ return false;
+ } else {
+ if (!circ->ccontrol)
+ return false;
+ }
+ }
+
+ /* For clients, this is mostly for sbws. For relays, this is an emergency
+ * emergency override, in case a bug is discovered by a relay operator
+ * and we can't set a consensus param fast enough. Basically gives them
+ * an option other than downgrading. */
+ if (opts->ConfluxEnabled != -1) {
+ if (server_mode(opts)) {
+ char *msg;
+ static ratelim_t rlimit = RATELIM_INIT(60 * 60); /* Hourly */
+ if ((msg = rate_limit_log(&rlimit, time(NULL)))) {
+ log_warn(LD_GENERAL,
+ "This tor is a relay and ConfluxEnabled is set to 0. "
+ "We would ask you to please write to us on "
+ "tor-relay@lists.torproject.org or file a bug explaining "
+ "why you have disabled this option. Without news from you, "
+ "we might end up marking your relay as a BadExit.");
+ tor_free(msg);
+ }
+ }
+ return opts->ConfluxEnabled;
+ }
+
+ return conflux_enabled;
+}
+
+/** Return the maximum number of linked set we are allowed to have. */
+uint8_t
+conflux_params_get_max_linked_set(void)
+{
+ return max_linked_set;
+}
+
+/** Return the number of maximum pre built sets that is allowed to have. */
+uint8_t
+conflux_params_get_max_prebuilt(void)
+{
+ /* Without any Exit supporting conflux, we won't be able to build a set. The
+ * float problem here is minimal because exit_conflux_ratio is either a flat
+ * 0 or else it means we do have at least an exit. */
+ if (exit_conflux_ratio <= 0.0) {
+ return 0;
+ }
+
+ /* Allow only 1 pre built set if we are lower than the low exit threshold
+ * parameter from the consensus. */
+ if (exit_conflux_ratio < low_exit_threshold_ratio) {
+ return 1;
+ }
+ return max_prebuilt_set;
+}
+
+/** Return the maximum number of retry we can do until a leg links. */
+uint8_t
+conflux_params_get_max_unlinked_leg_retry(void)
+{
+ return max_unlinked_leg_retry;
+}
+
+/** Return the number of legs per set. */
+uint8_t
+conflux_params_get_num_legs_set(void)
+{
+ return num_legs_set;
+}
+
+/** Return the drain percent we must hit before switching */
+uint8_t
+conflux_params_get_drain_pct(void)
+{
+ return cfx_drain_pct;
+}
+
+/** Return the percent of the congestion window to send before switching. */
+uint8_t
+conflux_params_get_send_pct(void)
+{
+ return cfx_send_pct;
+}
+
+/** Update global conflux related consensus parameter values, every consensus
+ * update. */
+void
+conflux_params_new_consensus(const networkstatus_t *ns)
+{
+ /* Params used by conflux_pool.c */
+ conflux_enabled =
+ networkstatus_get_param(ns, "cfx_enabled",
+ CONFLUX_ENABLED_DEFAULT,
+ CONFLUX_ENABLED_MIN, CONFLUX_ENABLED_MAX);
+
+ low_exit_threshold_ratio =
+ networkstatus_get_param(ns, "cfx_low_exit_threshold",
+ LOW_EXIT_THRESHOLD_DEFAULT,
+ LOW_EXIT_THRESHOLD_MIN, LOW_EXIT_THRESHOLD_MAX) /
+ (double)LOW_EXIT_THRESHOLD_MAX;
+
+ max_linked_set =
+ networkstatus_get_param(ns, "cfx_max_linked_set",
+ MAX_LINKED_SET_DEFAULT,
+ MAX_LINKED_SET_MIN, MAX_LINKED_SET_MAX);
+
+ max_prebuilt_set =
+ networkstatus_get_param(ns, "cfx_max_prebuilt_set",
+ MAX_PREBUILT_SET_DEFAULT,
+ MAX_PREBUILT_SET_MIN, MAX_PREBUILT_SET_MAX);
+
+ max_unlinked_leg_retry =
+ networkstatus_get_param(ns, "cfx_max_unlinked_leg_retry",
+ MAX_UNLINKED_LEG_RETRY_DEFAULT,
+ MAX_UNLINKED_LEG_RETRY_MIN,
+ MAX_UNLINKED_LEG_RETRY_MAX);
+
+ num_legs_set =
+ networkstatus_get_param(ns, "cfx_num_legs_set",
+ NUM_LEGS_SET_DEFAULT,
+ NUM_LEGS_SET_MIN, NUM_LEGS_SET_MAX);
+
+ /* Params used by conflux.c */
+ cfx_send_pct = networkstatus_get_param(ns, "cfx_send_pct",
+ CFX_SEND_PCT_DFLT,
+ CFX_SEND_PCT_MIN,
+ CFX_SEND_PCT_MAX);
+
+ cfx_drain_pct = networkstatus_get_param(ns, "cfx_drain_pct",
+ CFX_DRAIN_PCT_DFLT,
+ CFX_DRAIN_PCT_MIN,
+ CFX_DRAIN_PCT_MAX);
+
+ count_exit_with_conflux_support(ns);
+}
projects / thirdparty / tor.git / commitdiff
