commit f1d0c2d8260657925bfff32cf01417e735263e22
Author: Mike Perry <mikeperry-git(a)torproject.org>
Date: Thu Jun 10 23:08:24 2021 +0000
Prop#324: Common RTT, BDP, and blocked channel signal support
---
src/core/or/congestion_control_common.c | 933 ++++++++++++++++++++++++++++++++
src/core/or/congestion_control_common.h | 55 ++
src/core/or/congestion_control_st.h | 257 +++++++++
src/core/or/include.am | 2 +
4 files changed, 1247 insertions(+)
diff --git a/src/core/or/congestion_control_common.c b/src/core/or/congestion_control_common.c
new file mode 100644
index 0000000000..9db1d7d664
--- /dev/null
+++ b/src/core/or/congestion_control_common.c
@@ -0,0 +1,933 @@
+/* Copyright (c) 2021, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file congestion_control_common.c
+ * \brief Common code used by all congestion control algorithms.
+ */
+
+#define TOR_CONGESTION_CONTROL_COMMON_PRIVATE
+
+#include "core/or/or.h"
+
+#include "core/or/circuitlist.h"
+#include "core/or/crypt_path.h"
+#include "core/or/or_circuit_st.h"
+#include "core/or/origin_circuit_st.h"
+#include "core/or/channel.h"
+#include "core/mainloop/connection.h"
+#include "core/or/sendme.h"
+#include "core/or/congestion_control_common.h"
+#include "core/or/congestion_control_vegas.h"
+#include "core/or/congestion_control_nola.h"
+#include "core/or/congestion_control_westwood.h"
+#include "core/or/congestion_control_st.h"
+#include "lib/time/compat_time.h"
+#include "feature/nodelist/networkstatus.h"
+
+/* Consensus parameter defaults */
+#define CIRCWINDOW_INIT (500)
+
+#define CWND_INC_PCT_SS_DFLT (100)
+
+#define SENDME_INC_DFLT (50)
+#define CWND_MIN_DFLT (MAX(100, SENDME_INC_DFLT))
+
+#define CWND_INC_DFLT (50)
+
+#define CWND_INC_RATE_DFLT (1)
+
+#define WESTWOOD_BDP_ALG BDP_ALG_PIECEWISE
+#define VEGAS_BDP_MIX_ALG BDP_ALG_PIECEWISE
+#define NOLA_BDP_ALG BDP_ALG_PIECEWISE
+
+#define EWMA_CWND_COUNT_DFLT 2
+
+#define BWE_SENDME_MIN_DFLT 5
+
+static uint64_t congestion_control_update_circuit_rtt(congestion_control_t *,
+ uint64_t);
+static bool congestion_control_update_circuit_bdp(congestion_control_t *,
+ const circuit_t *,
+ const crypt_path_t *,
+ uint64_t, uint64_t);
+
+/**
+ * Set congestion control parameters on a circuit's congestion
+ * control object based on values from the consensus.
+ *
+ * cc_alg is the negotiated congestion control algorithm.
+ *
+ * sendme_inc is the number of packaged cells that a sendme cell
+ * acks. This parameter will come from circuit negotiation.
+ */
+static void
+congestion_control_init_params(congestion_control_t *cc,
+ cc_alg_t cc_alg,
+ int sendme_inc)
+{
+#define CWND_INIT_MIN 100
+#define CWND_INIT_MAX (10000)
+ cc->cwnd =
+ networkstatus_get_param(NULL, "cc_cwnd_init",
+ CIRCWINDOW_INIT,
+ CWND_INIT_MIN,
+ CWND_INIT_MAX);
+
+#define CWND_INC_PCT_SS_MIN 1
+#define CWND_INC_PCT_SS_MAX (500)
+ cc->cwnd_inc_pct_ss =
+ networkstatus_get_param(NULL, "cc_cwnd_inc_pct_ss",
+ CWND_INC_PCT_SS_DFLT,
+ CWND_INC_PCT_SS_MIN,
+ CWND_INC_PCT_SS_MAX);
+
+#define CWND_INC_MIN 1
+#define CWND_INC_MAX (1000)
+ cc->cwnd_inc =
+ networkstatus_get_param(NULL, "cc_cwnd_inc",
+ CWND_INC_DFLT,
+ CWND_INC_MIN,
+ CWND_INC_MAX);
+
+#define CWND_INC_RATE_MIN 1
+#define CWND_INC_RATE_MAX (250)
+ cc->cwnd_inc_rate =
+ networkstatus_get_param(NULL, "cc_cwnd_inc_rate",
+ CWND_INC_RATE_DFLT,
+ CWND_INC_RATE_MIN,
+ CWND_INC_RATE_MAX);
+
+#define SENDME_INC_MIN 10
+#define SENDME_INC_MAX (1000)
+ cc->sendme_inc =
+ networkstatus_get_param(NULL, "cc_sendme_inc",
+ sendme_inc,
+ SENDME_INC_MIN,
+ SENDME_INC_MAX);
+
+ // XXX: this min needs to abide by sendme_inc range rules somehow
+#define CWND_MIN_MIN sendme_inc
+#define CWND_MIN_MAX (1000)
+ cc->cwnd_min =
+ networkstatus_get_param(NULL, "cc_cwnd_min",
+ CWND_MIN_DFLT,
+ CWND_MIN_MIN,
+ CWND_MIN_MAX);
+
+#define EWMA_CWND_COUNT_MIN 1
+#define EWMA_CWND_COUNT_MAX (100)
+ cc->ewma_cwnd_cnt =
+ networkstatus_get_param(NULL, "cc_ewma_cwnd_cnt",
+ EWMA_CWND_COUNT_DFLT,
+ EWMA_CWND_COUNT_MIN,
+ EWMA_CWND_COUNT_MAX);
+
+#define BWE_SENDME_MIN_MIN 2
+#define BWE_SENDME_MIN_MAX (20)
+ cc->bwe_sendme_min =
+ networkstatus_get_param(NULL, "cc_bwe_min",
+ BWE_SENDME_MIN_DFLT,
+ BWE_SENDME_MIN_MIN,
+ BWE_SENDME_MIN_MAX);
+
+#define CC_ALG_MIN 0
+#define CC_ALG_MAX (NUM_CC_ALGS-1)
+ cc->cc_alg =
+ networkstatus_get_param(NULL, "cc_alg",
+ cc_alg,
+ CC_ALG_MIN,
+ CC_ALG_MAX);
+
+ bdp_alg_t default_bdp_alg = 0;
+
+ switch (cc->cc_alg) {
+ case CC_ALG_WESTWOOD:
+ default_bdp_alg = WESTWOOD_BDP_ALG;
+ break;
+ case CC_ALG_VEGAS:
+ default_bdp_alg = VEGAS_BDP_MIX_ALG;
+ break;
+ case CC_ALG_NOLA:
+ default_bdp_alg = NOLA_BDP_ALG;
+ break;
+ case CC_ALG_SENDME:
+ default:
+ tor_fragile_assert();
+ return; // No alg-specific params
+ }
+
+ cc->bdp_alg =
+ networkstatus_get_param(NULL, "cc_bdp_alg",
+ default_bdp_alg,
+ 0,
+ NUM_BDP_ALGS-1);
+
+ /* Algorithm-specific parameters */
+ if (cc->cc_alg == CC_ALG_WESTWOOD) {
+ congestion_control_westwood_set_params(cc);
+ } else if (cc->cc_alg == CC_ALG_VEGAS) {
+ congestion_control_vegas_set_params(cc);
+ } else if (cc->cc_alg == CC_ALG_NOLA) {
+ congestion_control_nola_set_params(cc);
+ }
+}
+
+/**
+ * Allocate and initialize fields in congestion control object.
+ *
+ * cc_alg is the negotiated congestion control algorithm.
+ *
+ * sendme_inc is the number of packaged cells that a sendme cell
+ * acks. This parameter will come from circuit negotiation.
+ */
+static void
+congestion_control_init(congestion_control_t *cc, cc_alg_t cc_alg,
+ int sendme_inc)
+{
+ cc->sendme_pending_timestamps = smartlist_new();
+ cc->sendme_arrival_timestamps = smartlist_new();
+
+ cc->in_slow_start = 1;
+ congestion_control_init_params(cc, cc_alg, sendme_inc);
+
+ cc->next_cc_event = CWND_UPDATE_RATE(cc);
+}
+
+/** Allocate and initialize a new congestion control object */
+congestion_control_t *
+congestion_control_new(void)
+{
+ congestion_control_t *cc = tor_malloc_zero(sizeof(congestion_control_t));
+
+ // XXX: the alg and the sendme_inc need to be negotiated during
+ // circuit handshake
+ congestion_control_init(cc, CC_ALG_VEGAS, SENDME_INC_DFLT);
+
+ return cc;
+}
+
+/**
+ * Free a congestion control object and its asssociated state.
+ */
+void
+congestion_control_free_(congestion_control_t *cc)
+{
+ if (!cc)
+ return;
+
+ SMARTLIST_FOREACH(cc->sendme_pending_timestamps, uint64_t *, t, tor_free(t));
+ SMARTLIST_FOREACH(cc->sendme_arrival_timestamps, uint64_t *, t, tor_free(t));
+ smartlist_free(cc->sendme_pending_timestamps);
+ smartlist_free(cc->sendme_arrival_timestamps);
+
+ tor_free(cc);
+}
+
+/**
+ * Compute an N-count EWMA, aka N-EWMA. N-EWMA is defined as:
+ * EWMA = alpha*value + (1-alpha)*EWMA_prev
+ * with alpha = 2/(N+1).
+ *
+ * This works out to:
+ * EWMA = value*2/(N+1) + EMA_prev*(N-1)/(N+1)
+ * = (value*2 + EWMA_prev*(N-1))/(N+1)
+ */
+static inline uint64_t
+n_count_ewma(uint64_t curr, uint64_t prev, uint64_t N)
+{
+ if (prev == 0)
+ return curr;
+ else
+ return (2*curr + (N-1)*prev)/(N+1);
+}
+
+/**
+ * Enqueue a u64 timestamp to the end of a queue of timestamps.
+ */
+static inline void
+enqueue_timestamp(smartlist_t *timestamps_u64, uint64_t timestamp_usec)
+{
+ uint64_t *timestamp_ptr = tor_malloc(sizeof(uint64_t));
+ *timestamp_ptr = timestamp_usec;
+
+ smartlist_add(timestamps_u64, timestamp_ptr);
+}
+
+/**
+ * Peek at the head of a smartlist queue of u64 timestamps.
+ */
+static inline uint64_t
+peek_timestamp(const smartlist_t *timestamps_u64_usecs)
+{
+ uint64_t *timestamp_ptr = smartlist_get(timestamps_u64_usecs, 0);
+
+ if (BUG(!timestamp_ptr)) {
+ log_err(LD_CIRC, "Congestion control timestamp list became empty!");
+ return 0;
+ }
+
+ return *timestamp_ptr;
+}
+
+/**
+ * Dequeue a u64 monotime usec timestamp from the front of a
+ * smartlist of pointers to 64.
+ */
+static inline uint64_t
+dequeue_timestamp(smartlist_t *timestamps_u64_usecs)
+{
+ uint64_t *timestamp_ptr = smartlist_get(timestamps_u64_usecs, 0);
+ uint64_t timestamp_u64;
+
+ if (BUG(!timestamp_ptr)) {
+ log_err(LD_CIRC, "Congestion control timestamp list became empty!");
+ return 0;
+ }
+
+ timestamp_u64 = *timestamp_ptr;
+ smartlist_del_keeporder(timestamps_u64_usecs, 0);
+ tor_free(timestamp_ptr);
+
+ return timestamp_u64;
+}
+
+/**
+ * Returns the number of sendme acks that will be recieved in the
+ * current congestion window size, rounded to nearest int.
+ */
+static inline uint64_t
+sendme_acks_per_cwnd(const congestion_control_t *cc)
+{
+ /* We add half a sendme_inc to cwnd to round to the nearest int */
+ return ((cc->cwnd + cc->sendme_inc/2)/cc->sendme_inc);
+}
+
+/**
+ * Get a package window from either old sendme logic, or congestion control.
+ *
+ * A package window is how many cells you can still send.
+ */
+int
+congestion_control_get_package_window(const circuit_t *circ,
+ const crypt_path_t *cpath)
+{
+ int package_window;
+ congestion_control_t *cc;
+
+ tor_assert(circ);
+
+ if (cpath) {
+ package_window = cpath->package_window;
+ cc = cpath->ccontrol;
+ } else {
+ package_window = circ->package_window;
+ cc = circ->ccontrol;
+ }
+
+ if (!cc) {
+ return package_window;
+ } else {
+ /* Inflight can be above cwnd if cwnd was just reduced */
+ if (cc->inflight > cc->cwnd)
+ return 0;
+ /* In the extremely unlikely event that cwnd-inflight is larger than
+ * INT32_MAX, just return that cap, so old code doesn't explode. */
+ else if (cc->cwnd - cc->inflight > INT32_MAX)
+ return INT32_MAX;
+ else
+ return (int)(cc->cwnd - cc->inflight);
+ }
+}
+
+/**
+ * Returns the number of cells that are acked by every sendme.
+ */
+int
+sendme_get_inc_count(const circuit_t *circ, const crypt_path_t *layer_hint)
+{
+ int sendme_inc = CIRCWINDOW_INCREMENT;
+ congestion_control_t *cc = NULL;
+
+ if (layer_hint) {
+ cc = layer_hint->ccontrol;
+ } else {
+ cc = circ->ccontrol;
+ }
+
+ if (cc) {
+ sendme_inc = cc->sendme_inc;
+ }
+
+ return sendme_inc;
+}
+
+/** Return true iff the next cell we send will result in the other endpoint
+ * sending a SENDME.
+ *
+ * We are able to know that because the package or inflight window value minus
+ * one cell (the possible SENDME cell) should be a multiple of the
+ * cells-per-sendme increment value (set via consensus parameter, negotiated
+ * for the circuit, and passed in as sendme_inc).
+ *
+ * This function is used when recording a cell digest and this is done quite
+ * low in the stack when decrypting or encrypting a cell. The window is only
+ * updated once the cell is actually put in the outbuf.
+ */
+bool
+circuit_sent_cell_for_sendme(const circuit_t *circ,
+ const crypt_path_t *layer_hint)
+{
+ congestion_control_t *cc;
+ int window;
+
+ tor_assert(circ);
+
+ if (layer_hint) {
+ window = layer_hint->package_window;
+ cc = layer_hint->ccontrol;
+ } else {
+ window = circ->package_window;
+ cc = circ->ccontrol;
+ }
+
+ /* If we are using congestion control and the alg is not
+ * old-school 'fixed', then use cc->inflight to determine
+ * when sendmes will be sent */
+ if (cc) {
+ if (!cc->inflight)
+ return false;
+
+ /* This check must be +1 because this function is called *before*
+ * inflight is incremented for the sent cell */
+ if ((cc->inflight+1) % cc->sendme_inc != 0)
+ return false;
+
+ return true;
+ }
+
+ /* At the start of the window, no SENDME will be expected. */
+ if (window == CIRCWINDOW_START) {
+ return false;
+ }
+
+ /* Are we at the limit of the increment and if not, we don't expect next
+ * cell is a SENDME.
+ *
+ * We test against the window minus 1 because when we are looking if the
+ * next cell is a SENDME, the window (either package or deliver) hasn't been
+ * decremented just yet so when this is called, we are currently processing
+ * the "window - 1" cell.
+ */
+ if (((window - 1) % CIRCWINDOW_INCREMENT) != 0) {
+ return false;
+ }
+
+ /* Next cell is expected to be a SENDME. */
+ return true;
+}
+
+/**
+ * Call-in to tell congestion control code that this circuit sent a cell.
+ *
+ * This updates the 'inflight' counter, and if this is a cell that will
+ * cause the other end to send a SENDME, record the current time in a list
+ * of pending timestamps, so that we can later compute the circuit RTT when
+ * the SENDME comes back. */
+void
+congestion_control_note_cell_sent(congestion_control_t *cc,
+ const circuit_t *circ,
+ const crypt_path_t *cpath)
+{
+ tor_assert(circ);
+ tor_assert(cc);
+
+ /* Is this the last cell before a SENDME? The idea is that if the
+ * package_window reaches a multiple of the increment, after this cell, we
+ * should expect a SENDME. Note that this function must be called *before*
+ * we account for the sent cell. */
+ if (!circuit_sent_cell_for_sendme(circ, cpath)) {
+ cc->inflight++;
+ return;
+ }
+
+ cc->inflight++;
+
+ /* Record this cell time for RTT computation when SENDME arrives */
+ enqueue_timestamp(cc->sendme_pending_timestamps,
+ monotime_absolute_usec());
+}
+
+/**
+ * Returns true if any edge connections are active.
+ *
+ * We need to know this so that we can stop computing BDP if the
+ * edges are not sending on the circuit.
+ */
+static int
+circuit_has_active_streams(const circuit_t *circ,
+ const crypt_path_t *layer_hint)
+{
+ const edge_connection_t *streams;
+
+ if (CIRCUIT_IS_ORIGIN(circ)) {
+ streams = CONST_TO_ORIGIN_CIRCUIT(circ)->p_streams;
+ } else {
+ streams = CONST_TO_OR_CIRCUIT(circ)->n_streams;
+ }
+
+ /* Check linked list of streams */
+ for (const edge_connection_t *conn = streams; conn != NULL;
+ conn = conn->next_stream) {
+ if (conn->base_.marked_for_close)
+ continue;
+
+ if (!layer_hint || conn->cpath_layer == layer_hint) {
+ if (connection_get_inbuf_len(TO_CONN(conn)) > 0) {
+ log_info(LD_CIRC, "CC: More in edge inbuf...");
+ return 1;
+ }
+
+ /* If we did not reach EOF on this read, there's more */
+ if (!TO_CONN(conn)->inbuf_reached_eof) {
+ log_info(LD_CIRC, "CC: More on edge conn...");
+ return 1;
+ }
+
+ if (TO_CONN(conn)->linked_conn) {
+ if (connection_get_inbuf_len(TO_CONN(conn)->linked_conn) > 0) {
+ log_info(LD_CIRC, "CC: More in linked inbuf...");
+ return 1;
+ }
+
+ /* If there is a linked conn, and *it* did not each EOF,
+ * there's more */
+ if (!TO_CONN(conn)->linked_conn->inbuf_reached_eof) {
+ log_info(LD_CIRC, "CC: More on linked conn...");
+ return 1;
+ }
+ }
+ }
+ }
+
+ return 0;
+}
+
+/**
+ * Upon receipt of a SENDME, pop the oldest timestamp off the timestamp
+ * list, and use this to update RTT.
+ *
+ * Returns true if circuit estimates were successfully updated, false
+ * otherwise.
+ */
+bool
+congestion_control_update_circuit_estimates(congestion_control_t *cc,
+ const circuit_t *circ,
+ const crypt_path_t *layer_hint)
+{
+ uint64_t now_usec = monotime_absolute_usec();
+
+ /* Update RTT first, then BDP. BDP needs fresh RTT */
+ uint64_t curr_rtt_usec = congestion_control_update_circuit_rtt(cc, now_usec);
+ return congestion_control_update_circuit_bdp(cc, circ, layer_hint, now_usec,
+ curr_rtt_usec);
+}
+
+/**
+ * Returns true if we have enough time data to use heuristics
+ * to compare RTT to a baseline.
+ */
+static bool
+time_delta_should_use_heuristics(const congestion_control_t *cc)
+{
+
+ /* If we have exited slow start, we should have processed at least
+ * a cwnd worth of RTTs */
+ if (!cc->in_slow_start) {
+ return true;
+ }
+
+ /* If we managed to get enough acks to estimate a SENDME BDP, then
+ * we have enough to estimate clock jumps relative to a baseline,
+ * too. (This is at least 'cc_bwe_min' acks). */
+ if (cc->bdp[BDP_ALG_SENDME_RATE]) {
+ return true;
+ }
+
+ /* Not enough data to estimate clock jumps */
+ return false;
+}
+
+/**
+ * Returns true if the monotime delta is 0, or is significantly
+ * different than the previous delta. Either case indicates
+ * that the monotime time source stalled or jumped.
+ */
+static bool
+time_delta_stalled_or_jumped(const congestion_control_t *cc,
+ uint64_t old_delta, uint64_t new_delta)
+{
+#define DELTA_DISCREPENCY_RATIO_MAX 100
+ /* If we have a 0 new_delta, that is definitely a monotime stall */
+ if (new_delta == 0) {
+ static ratelim_t stall_info_limit = RATELIM_INIT(60);
+ log_fn_ratelim(&stall_info_limit, LOG_INFO, LD_CIRC,
+ "Congestion control cannot measure RTT due to monotime stall.");
+ return true;
+ }
+
+ /* If the old_delta is 0, we have no previous values. So
+ * just assume this one is valid (beause it is non-zero) */
+ if (old_delta == 0)
+ return false;
+
+ /*
+ * For the heuristic cases, we need at least a few timestamps,
+ * to average out any previous partial stalls or jumps. So until
+ * than point, let's just delcare these time values "good enough
+ * to use".
+ */
+ if (!time_delta_should_use_heuristics(cc)) {
+ return false;
+ }
+
+ /* If old_delta is significantly larger than new_delta, then
+ * this means that the monotime clock recently stopped moving
+ * forward. */
+ if (old_delta > new_delta * DELTA_DISCREPENCY_RATIO_MAX) {
+ static ratelim_t dec_notice_limit = RATELIM_INIT(300);
+ log_fn_ratelim(&dec_notice_limit, LOG_NOTICE, LD_CIRC,
+ "Sudden decrease in circuit RTT (%"PRIu64" vs %"PRIu64
+ "), likely due to clock jump.",
+ new_delta/1000, old_delta/1000);
+
+ return true;
+ }
+
+ /* If new_delta is significantly larger than old_delta, then
+ * this means that the monotime clock suddenly jumped forward. */
+ if (new_delta > old_delta * DELTA_DISCREPENCY_RATIO_MAX) {
+ static ratelim_t dec_notice_limit = RATELIM_INIT(300);
+ log_fn_ratelim(&dec_notice_limit, LOG_NOTICE, LD_CIRC,
+ "Sudden increase in circuit RTT (%"PRIu64" vs %"PRIu64
+ "), likely due to clock jump.",
+ new_delta/1000, old_delta/1000);
+
+ return true;
+ }
+
+ return false;
+}
+
+/**
+ * Called when we get a SENDME. Updates circuit RTT by pulling off a
+ * timestamp of when we sent the CIRCWINDOW_INCREMENT-th cell from
+ * the queue of such timestamps, and comparing that to current time.
+ *
+ * Also updates min, max, and EWMA of RTT.
+ *
+ * Returns the current circuit RTT in usecs, or 0 if it could not be
+ * measured (due to clock jump, stall, etc).
+ */
+static uint64_t
+congestion_control_update_circuit_rtt(congestion_control_t *cc,
+ uint64_t now_usec)
+{
+ uint64_t rtt, ewma_cnt;
+ uint64_t sent_at_timestamp;
+
+ tor_assert(cc);
+
+ /* Get the time that we sent the cell that resulted in the other
+ * end sending this sendme. Use this to calculate RTT */
+ sent_at_timestamp = dequeue_timestamp(cc->sendme_pending_timestamps);
+
+ rtt = now_usec - sent_at_timestamp;
+
+ /* Do not update RTT at all if it looks fishy */
+ if (time_delta_stalled_or_jumped(cc, cc->ewma_rtt_usec, rtt)) {
+ return 0;
+ }
+
+ ewma_cnt = cc->ewma_cwnd_cnt*sendme_acks_per_cwnd(cc);
+ ewma_cnt = MAX(ewma_cnt, 2); // Use at least 2
+
+ cc->ewma_rtt_usec = n_count_ewma(rtt, cc->ewma_rtt_usec, ewma_cnt);
+
+ if (rtt > cc->max_rtt_usec) {
+ cc->max_rtt_usec = rtt;
+ }
+
+ if (cc->min_rtt_usec == 0 || rtt < cc->min_rtt_usec) {
+ cc->min_rtt_usec = rtt;
+ }
+
+ return rtt;
+}
+
+/**
+ * Called when we get a SENDME. Updates the bandwidth-delay-product (BDP)
+ * estimates of a circuit. Several methods of computing BDP are used,
+ * depending on scenario. While some congestion control algorithms only
+ * use one of these methods, we update them all because it's quick and easy.
+ *
+ * - now_usec is the current monotime in usecs.
+ * - curr_rtt_usec is the current circuit RTT in usecs. It may be 0 if no
+ * RTT could bemeasured.
+ *
+ * Returns true if we were able to update BDP, false otherwise.
+ */
+static bool
+congestion_control_update_circuit_bdp(congestion_control_t *cc,
+ const circuit_t *circ,
+ const crypt_path_t *layer_hint,
+ uint64_t now_usec,
+ uint64_t curr_rtt_usec)
+{
+ int chan_q = 0;
+ unsigned int blocked_on_chan = 0;
+ uint64_t timestamp_usec;
+ uint64_t sendme_rate_bdp = 0;
+
+ tor_assert(cc);
+
+ if (CIRCUIT_IS_ORIGIN(circ)) {
+ /* origin circs use n_chan */
+ chan_q = circ->n_chan_cells.n;
+ blocked_on_chan = circ->streams_blocked_on_n_chan;
+ } else {
+ /* Both onion services and exits use or_circuit and p_chan */
+ chan_q = CONST_TO_OR_CIRCUIT(circ)->p_chan_cells.n;
+ blocked_on_chan = circ->streams_blocked_on_p_chan;
+ }
+
+ /* If we have no EWMA RTT, it is because monotime has been stalled
+ * or messed up the entire time so far. Set our BDP estimates directly
+ * to current cwnd */
+ if (!cc->ewma_rtt_usec) {
+ uint64_t cwnd = cc->cwnd;
+
+ /* If the channel is blocked, keep subtracting off the chan_q
+ * until we hit the min cwnd. */
+ if (blocked_on_chan) {
+ cwnd = MAX(cwnd - chan_q, cc->cwnd_min);
+ cc->blocked_chan = 1;
+ } else {
+ cc->blocked_chan = 0;
+ }
+
+ cc->bdp[BDP_ALG_CWND_RTT] = cwnd;
+ cc->bdp[BDP_ALG_INFLIGHT_RTT] = cwnd;
+ cc->bdp[BDP_ALG_SENDME_RATE] = cwnd;
+ cc->bdp[BDP_ALG_PIECEWISE] = cwnd;
+
+ static ratelim_t dec_notice_limit = RATELIM_INIT(300);
+ log_fn_ratelim(&dec_notice_limit, LOG_NOTICE, LD_CIRC,
+ "Our clock has been stalled for the entire lifetime of a circuit. "
+ "Performance may be sub-optimal.");
+
+ return blocked_on_chan;
+ }
+
+ /* Congestion window based BDP will respond to changes in RTT only, and is
+ * relative to cwnd growth. It is useful for correcting for BDP
+ * overestimation, but if BDP is higher than the current cwnd, it will
+ * underestimate it.
+ *
+ * We multiply here first to avoid precision issues from min_RTT being
+ * close to ewma RTT. Since all fields are u64, there is plenty of
+ * room here to multiply first.
+ */
+ cc->bdp[BDP_ALG_CWND_RTT] = cc->cwnd*cc->min_rtt_usec/cc->ewma_rtt_usec;
+
+ /*
+ * If we have no pending streams, we do not have enough data to fill
+ * the BDP, so preserve our old estimates but do not make any more.
+ */
+ if (!blocked_on_chan && !circuit_has_active_streams(circ, layer_hint)) {
+ log_info(LD_CIRC,
+ "CC: Streams drained. Spare package window: %"PRIu64
+ ", no BDP update", cc->cwnd - cc->inflight);
+
+ /* Clear SENDME timestamps; they will be wrong with intermittent data */
+ SMARTLIST_FOREACH(cc->sendme_arrival_timestamps, uint64_t *, t,
+ tor_free(t));
+ smartlist_clear(cc->sendme_arrival_timestamps);
+ } else if (curr_rtt_usec) {
+ /* Sendme-based BDP will quickly measure BDP in much less than
+ * a cwnd worth of data when in use (in 2-10 SENDMEs).
+ *
+ * But if the link goes idle, it will be vastly lower than true BDP. Hence
+ * we only compute it if we have either pending stream data, or streams
+ * are still blocked on the channel queued data.
+ *
+ * We also do not compute it if we do not have a current RTT passed in,
+ * because that means that monotime is currently stalled or just jumped.
+ */
+ enqueue_timestamp(cc->sendme_arrival_timestamps, now_usec);
+
+ if (smartlist_len(cc->sendme_arrival_timestamps) >= cc->bwe_sendme_min) {
+ /* If we have more sendmes than fit in a cwnd, trim the list.
+ * Those are not acurrately measuring throughput, if cwnd is
+ * currently smaller than BDP */
+ while (smartlist_len(cc->sendme_arrival_timestamps) >
+ cc->bwe_sendme_min &&
+ (uint64_t)smartlist_len(cc->sendme_arrival_timestamps) >
+ sendme_acks_per_cwnd(cc)) {
+ (void)dequeue_timestamp(cc->sendme_arrival_timestamps);
+ }
+ int sendme_cnt = smartlist_len(cc->sendme_arrival_timestamps);
+
+ /* Calculate SENDME_BWE_COUNT pure average */
+ timestamp_usec = peek_timestamp(cc->sendme_arrival_timestamps);
+ uint64_t delta = now_usec - timestamp_usec;
+
+ /* The acked data is in sendme_cnt-1 chunks, because we are counting the
+ * data that is processed by the other endpoint *between* all of these
+ * sendmes. There's one less gap between the sendmes than the number
+ * of sendmes. */
+ uint64_t cells = (sendme_cnt-1)*cc->sendme_inc;
+
+ /* The bandwidth estimate is cells/delta, which when multiplied
+ * by min RTT obtains the BDP. However, we multiply first to
+ * avoid precision issues with the RTT being close to delta in size. */
+ sendme_rate_bdp = cells*cc->min_rtt_usec/delta;
+
+ /* Calculate BDP_EWMA_COUNT N-EWMA */
+ cc->bdp[BDP_ALG_SENDME_RATE] =
+ n_count_ewma(sendme_rate_bdp, cc->bdp[BDP_ALG_SENDME_RATE],
+ cc->ewma_cwnd_cnt*sendme_acks_per_cwnd(cc));
+ }
+
+ /* In-flight BDP will cause the cwnd to drift down when underutilized.
+ * It is most useful when the local OR conn is blocked, so we only
+ * compute it if we're utilized. */
+ cc->bdp[BDP_ALG_INFLIGHT_RTT] =
+ (cc->inflight - chan_q)*cc->min_rtt_usec/
+ MAX(cc->ewma_rtt_usec, curr_rtt_usec);
+ } else {
+ /* We can still update inflight with just an EWMA RTT, but only
+ * if there is data flowing */
+ cc->bdp[BDP_ALG_INFLIGHT_RTT] =
+ (cc->inflight - chan_q)*cc->min_rtt_usec/cc->ewma_rtt_usec;
+ }
+
+ /* The orconn is blocked; use smaller of inflight vs SENDME */
+ if (blocked_on_chan) {
+ log_info(LD_CIRC, "CC: Streams blocked on circ channel. Chanq: %d",
+ chan_q);
+
+ /* A blocked channel is an immediate congestion signal, but it still
+ * happens only once per cwnd */
+ if (!cc->blocked_chan) {
+ cc->next_cc_event = 0;
+ cc->blocked_chan = 1;
+ }
+
+ if (cc->bdp[BDP_ALG_SENDME_RATE]) {
+ cc->bdp[BDP_ALG_PIECEWISE] = MIN(cc->bdp[BDP_ALG_INFLIGHT_RTT],
+ cc->bdp[BDP_ALG_SENDME_RATE]);
+ } else {
+ cc->bdp[BDP_ALG_PIECEWISE] = cc->bdp[BDP_ALG_INFLIGHT_RTT];
+ }
+ } else {
+ /* If we were previously blocked, emit a new congestion event
+ * now that we are unblocked, to re-evaluate cwnd */
+ if (cc->blocked_chan) {
+ cc->blocked_chan = 0;
+ cc->next_cc_event = 0;
+ log_info(LD_CIRC, "CC: Streams un-blocked on circ channel. Chanq: %d",
+ chan_q);
+ }
+
+ cc->bdp[BDP_ALG_PIECEWISE] = MAX(cc->bdp[BDP_ALG_SENDME_RATE],
+ cc->bdp[BDP_ALG_CWND_RTT]);
+ }
+
+ /* We can end up with no piecewise value if we didn't have either
+ * a SENDME estimate or enough data for an inflight estimate.
+ * It also happens on the very first sendme, since we need two
+ * to get a BDP. In these cases, use the cwnd method. */
+ if (!cc->bdp[BDP_ALG_PIECEWISE]) {
+ cc->bdp[BDP_ALG_PIECEWISE] = cc->bdp[BDP_ALG_CWND_RTT];
+ log_info(LD_CIRC, "CC: No piecewise BDP. Using %"PRIu64,
+ cc->bdp[BDP_ALG_PIECEWISE]);
+ }
+
+ if (cc->next_cc_event == 0) {
+ if (CIRCUIT_IS_ORIGIN(circ)) {
+ log_info(LD_CIRC,
+ "CC: Circuit %d "
+ "SENDME RTT: %"PRIu64", %"PRIu64", %"PRIu64", %"PRIu64", "
+ "BDP estimates: "
+ "%"PRIu64", "
+ "%"PRIu64", "
+ "%"PRIu64", "
+ "%"PRIu64", "
+ "%"PRIu64". ",
+ CONST_TO_ORIGIN_CIRCUIT(circ)->global_identifier,
+ cc->min_rtt_usec/1000,
+ curr_rtt_usec/1000,
+ cc->ewma_rtt_usec/1000,
+ cc->max_rtt_usec/1000,
+ cc->bdp[BDP_ALG_INFLIGHT_RTT],
+ cc->bdp[BDP_ALG_CWND_RTT],
+ sendme_rate_bdp,
+ cc->bdp[BDP_ALG_SENDME_RATE],
+ cc->bdp[BDP_ALG_PIECEWISE]
+ );
+ } else {
+ log_info(LD_CIRC,
+ "CC: Circuit %"PRIu64":%d "
+ "SENDME RTT: %"PRIu64", %"PRIu64", %"PRIu64", %"PRIu64", "
+ "%"PRIu64", "
+ "%"PRIu64", "
+ "%"PRIu64", "
+ "%"PRIu64", "
+ "%"PRIu64". ",
+ // XXX: actually, is this p_chan here? This is
+ // an or_circuit (exit or onion)
+ circ->n_chan->global_identifier, circ->n_circ_id,
+ cc->min_rtt_usec/1000,
+ curr_rtt_usec/1000,
+ cc->ewma_rtt_usec/1000,
+ cc->max_rtt_usec/1000,
+ cc->bdp[BDP_ALG_INFLIGHT_RTT],
+ cc->bdp[BDP_ALG_CWND_RTT],
+ sendme_rate_bdp,
+ cc->bdp[BDP_ALG_SENDME_RATE],
+ cc->bdp[BDP_ALG_PIECEWISE]
+ );
+ }
+ }
+
+ /* We updated BDP this round if either we had a blocked channel, or
+ * the curr_rtt_usec was not 0. */
+ return (blocked_on_chan || curr_rtt_usec != 0);
+}
+
+/**
+ * Dispatch the sendme to the appropriate congestion control algorithm.
+ */
+int
+congestion_control_dispatch_cc_alg(congestion_control_t *cc,
+ const circuit_t *circ,
+ const crypt_path_t *layer_hint)
+{
+ switch (cc->cc_alg) {
+ case CC_ALG_WESTWOOD:
+ return congestion_control_westwood_process_sendme(cc, circ, layer_hint);
+
+ case CC_ALG_VEGAS:
+ return congestion_control_vegas_process_sendme(cc, circ, layer_hint);
+
+ case CC_ALG_NOLA:
+ return congestion_control_nola_process_sendme(cc, circ, layer_hint);
+
+ case CC_ALG_SENDME:
+ default:
+ tor_assert(0);
+ }
+
+ return -END_CIRC_REASON_INTERNAL;
+}
diff --git a/src/core/or/congestion_control_common.h b/src/core/or/congestion_control_common.h
new file mode 100644
index 0000000000..4193d94cba
--- /dev/null
+++ b/src/core/or/congestion_control_common.h
@@ -0,0 +1,55 @@
+/* Copyright (c) 2019-2021, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file congestion_control_common.h
+ * \brief Public APIs for congestion control
+ **/
+
+#ifndef TOR_CONGESTION_CONTROL_COMMON_H
+#define TOR_CONGESTION_CONTROL_COMMON_H
+
+#include "core/or/crypt_path_st.h"
+#include "core/or/circuit_st.h"
+
+typedef struct congestion_control_t congestion_control_t;
+
+/** Wrapper for the free function, set the CC pointer to NULL after free */
+#define congestion_control_free(cc) \
+ FREE_AND_NULL(congestion_control_t, congestion_control_free_, cc)
+
+void congestion_control_free_(congestion_control_t *cc);
+
+congestion_control_t *congestion_control_new(void);
+
+int congestion_control_dispatch_cc_alg(congestion_control_t *cc,
+ const circuit_t *circ,
+ const crypt_path_t *layer_hint);
+
+void congestion_control_note_cell_sent(congestion_control_t *cc,
+ const circuit_t *circ,
+ const crypt_path_t *cpath);
+
+bool congestion_control_update_circuit_estimates(congestion_control_t *,
+ const circuit_t *,
+ const crypt_path_t *);
+
+int congestion_control_get_package_window(const circuit_t *,
+ const crypt_path_t *);
+
+int sendme_get_inc_count(const circuit_t *, const crypt_path_t *);
+bool circuit_sent_cell_for_sendme(const circuit_t *, const crypt_path_t *);
+
+/* Private section starts. */
+#ifdef TOR_CONGESTION_CONTROL_PRIVATE
+
+/*
+ * Unit tests declaractions.
+ */
+#ifdef TOR_UNIT_TESTS
+
+#endif /* defined(TOR_UNIT_TESTS) */
+
+#endif /* defined(TOR_CONGESTION_CONTROL_PRIVATE) */
+
+#endif /* !defined(TOR_CONGESTION_CONTROL_COMMON_H) */
diff --git a/src/core/or/congestion_control_st.h b/src/core/or/congestion_control_st.h
new file mode 100644
index 0000000000..251ebd82e3
--- /dev/null
+++ b/src/core/or/congestion_control_st.h
@@ -0,0 +1,257 @@
+/* Copyright (c) 2019-2021, The Tor Project, Inc. */
+/* See LICENSE for licensing information */
+
+/**
+ * \file congestion_control_st.h
+ * \brief Structure definitions for congestion control.
+ **/
+
+#ifndef CONGESTION_CONTROL_ST_H
+#define CONGESTION_CONTROL_ST_H
+
+#include "core/or/crypt_path_st.h"
+#include "core/or/circuit_st.h"
+
+/** Signifies which sendme algorithm to use */
+typedef enum {
+ /** OG Tor fixed-sized circ and stream windows. It sucks, but it is important
+ * to make sure that the new algs can compete with the old garbage. */
+ CC_ALG_SENDME = 0,
+
+ /**
+ * Prop#324 TOR_WESTWOOD - Deliberately agressive. Westwood may not even
+ * converge to fairness in some cases because max RTT will also increase
+ * on congesgtion, which boosts the Westwood RTT congestion threshhold. So it
+ * can cause runaway queue bloat, which may or may not lead to a robot
+ * uprising... Ok that's Westworld, not Westwood. Still, we need to test
+ * Vegas and NOLA against something more agressive to ensure they do not
+ * starve in the presence of cheaters. We also need to make sure cheaters
+ * trigger the oomkiller in those cases.
+ */
+ CC_ALG_WESTWOOD = 1,
+
+ /**
+ * Prop#324 TOR_VEGAS - TCP Vegas-style BDP tracker. Because Vegas backs off
+ * whenever it detects queue delay, it can be beaten out by more agressive
+ * algs. However, in live network testing, it seems to do just fine against
+ * current SENDMEs. It outperforms Westwood and does not stall. */
+ CC_ALG_VEGAS = 2,
+
+ /**
+ * Prop#324: TOR_NOLA - NOLA looks the BDP right in the eye and uses it
+ * immediately as CWND. No slow start, no other congestion signals, no delay,
+ * no bullshit. Like TOR_VEGAS, it also uses agressive BDP estimates, to
+ * avoid out-competition. It seems a bit better throughput than Vegas,
+ * but its agressive BDP and rapid updates may lead to more queue latency. */
+ CC_ALG_NOLA = 3,
+} cc_alg_t;
+
+/* Total number of CC algs in cc_alg_t enum */
+#define NUM_CC_ALGS (CC_ALG_NOLA+1)
+
+/** Signifies how we estimate circuit BDP */
+typedef enum {
+ /* CWND-based BDP will respond to changes in RTT only, and is relative
+ * to cwnd growth. So in slow-start, this will under-estimate BDP */
+ BDP_ALG_CWND_RTT = 0,
+
+ /* Sendme-based BDP will quickly measure BDP in less than
+ * a cwnd worth of data when in use. So it should be good for slow-start.
+ * But if the link goes idle, it will be vastly lower than true BDP. Thus,
+ * this estimate gets reset when the cwnd is not fully utilized. */
+ BDP_ALG_SENDME_RATE = 1,
+
+ /* Inflight BDP is similar to the cwnd estimator, except it uses
+ * packets inflight minus local circuit queues instead of current cwnd.
+ * Because it is strictly less than or equal to the cwnd, it will cause
+ * the cwnd to drift downward. It is only used if the local OR connection
+ * is blocked. */
+ BDP_ALG_INFLIGHT_RTT = 2,
+
+ /* The Piecewise BDP estimator uses the CWND estimator before there
+ * are sufficient SENDMEs to calculate the SENDME estimator. At that
+ * point, it uses the SENDME estimator, unless the local OR connection
+ * becomes blocked. In that case, it switches to the inflight estimator. */
+ BDP_ALG_PIECEWISE = 3,
+
+} bdp_alg_t;
+
+/** Total number of BDP algs in bdp_alg_t enum */
+#define NUM_BDP_ALGS (BDP_ALG_PIECEWISE+1)
+
+/** Westwood algorithm parameters */
+struct westwood_params_t {
+ /** Cwnd backoff multiplier upon congestion (as percent) */
+ uint8_t cwnd_backoff_m;
+ /** Max RTT backoff multiplier upon congestion (as percent) */
+ uint8_t rtt_backoff_m;
+
+ /** Threshold between min and max RTT, to signal congestion (percent) */
+ uint8_t rtt_thresh;
+
+ /**
+ * If true, use minimum of BDP and backoff multiplication in backoff.
+ * If false, use maximum of BDP and backoff multiplication in backoff. */
+ bool min_backoff;
+};
+
+/** Vegas algorithm parameters. */
+struct vegas_params_t {
+ /** The queue use allowed before we exit slow start */
+ uint16_t gamma;
+ /** The queue use below which we increment cwnd */
+ uint16_t alpha;
+ /** The queue use above which we decrement cwnd */
+ uint16_t beta;
+ /** Weighted average (percent) between cwnd estimator and
+ * piecewise estimator. */
+ uint8_t bdp_mix_pct;
+};
+
+/** NOLA consensus params */
+struct nola_params_t {
+ /** How many cells to add to BDP estimate to obtain cwnd */
+ uint16_t bdp_overshoot;
+};
+
+/** Fields common to all congestion control algorithms */
+typedef struct congestion_control_t {
+ /**
+ * Smartlist of uint64_t monotime usec timestamps of when we sent a data
+ * cell that is pending a sendme. FIFO queue that is managed similar to
+ * sendme_last_digests. */
+ smartlist_t *sendme_pending_timestamps;
+
+ /**
+ * Smartlist of uint64_t monotime timestamp of when sendme's arrived.
+ * FIFO queue that is managed similar to sendme_last_digests.
+ * Used to estimate circuitbandwidth and BDP. */
+ smartlist_t *sendme_arrival_timestamps;
+
+ /** RTT time data for congestion control. */
+ uint64_t ewma_rtt_usec;
+ uint64_t min_rtt_usec;
+ uint64_t max_rtt_usec;
+
+ /* BDP estimates by algorithm */
+ uint64_t bdp[NUM_BDP_ALGS];
+
+ /** Congestion window */
+ uint64_t cwnd;
+
+ /** Number of cells in-flight (sent but awaiting SENDME ack). */
+ uint64_t inflight;
+
+ /**
+ * For steady-state: the number of sendme acks until we will acknowledge
+ * a congestion event again. It starts out as the number of sendme acks
+ * in a congestion windowm and is decremented each ack. When this reaches
+ * 0, it means we should examine our congestion algorithm conditions.
+ * In this way, we only react to one congestion event per congestion window.
+ *
+ * It is also reset to 0 immediately whenever the circuit's orconn is
+ * blocked, and when a previously blocked orconn is unblocked.
+ */
+ uint64_t next_cc_event;
+
+ /** Are we in slow start? */
+ bool in_slow_start;
+
+ /** Is the local channel blocked on us? That's a congestion signal */
+ bool blocked_chan;
+
+ /* The following parameters are cached from consensus values upon
+ * circuit setup. */
+
+ /** Percent of cwnd to increment by during slow start */
+ uint16_t cwnd_inc_pct_ss;
+
+ /** Number of cells to increment cwnd by during steady state */
+ uint16_t cwnd_inc;
+
+ /** Minimum congestion window (must be at least sendme_inc) */
+ uint16_t cwnd_min;
+
+ /**
+ * Number of times per congestion window to update based on congestion
+ * signals */
+ uint8_t cwnd_inc_rate;
+
+ /**
+ * Number of cwnd worth of sendme acks to smooth RTT and BDP with,
+ * using N_EWMA */
+ uint8_t ewma_cwnd_cnt;
+
+ /**
+ * Minimum number of sendmes before we begin BDP estimates
+ */
+ uint8_t bwe_sendme_min;
+
+ /**
+ * Number of cells to ack with every sendme. Taken from consensus parameter
+ * and negotiation during circuit setup. */
+ uint8_t sendme_inc;
+
+ /** Which congestion control algorithm to use. Taken from
+ * consensus parameter and negotiation during circuit setup. */
+ cc_alg_t cc_alg;
+
+ /** Which algorithm to estimate circuit bandwidth with. Taken from
+ * consensus parameter during circuit setup. */
+ bdp_alg_t bdp_alg;
+
+ /** Algorithm-specific parameters. The specific struct that is used
+ * depends upon the algoritghm selected by the cc_alg parameter.
+ * These should not be accessed anywhere other than the algorithm-specific
+ * files. */
+ union {
+ struct westwood_params_t westwood_params;
+ struct vegas_params_t vegas_params;
+ struct nola_params_t nola_params;
+ };
+} congestion_control_t;
+
+/**
+ * Returns the number of sendme acks we will recieve before we update cwnd.
+ *
+ * Congestion control literature recommends only one update of cwnd per
+ * cwnd worth of acks. However, we can also tune this to be more frequent
+ * by increasing the 'cc_cwnd_inc_rate' consensus parameter.
+ *
+ * If this returns 0 due to high cwnd_inc_rate, the calling code will
+ * update every sendme ack.
+ */
+static inline uint64_t CWND_UPDATE_RATE(const congestion_control_t *cc)
+{
+ /* We add cwnd_inc_rate*sendme_inc/2 to round to nearest integer number
+ * of acks */
+ return ((cc->cwnd + cc->cwnd_inc_rate*cc->sendme_inc/2)
+ / (cc->cwnd_inc_rate*cc->sendme_inc));
+}
+
+/**
+ * Returns the amount to increment the congestion window each update,
+ * during slow start.
+ *
+ * Congestion control literature recommends either doubling the cwnd
+ * every cwnd during slow start, or some similar exponential growth
+ * (such as 50% more every cwnd, for Vegas).
+ *
+ * This is controlled by a consensus parameter 'cwnd_inc_pct_ss', which
+ * allows us to specify the percent of the current consensus window
+ * to update by.
+ */
+static inline uint64_t CWND_INC_SS(const congestion_control_t *cc)
+{
+ return (cc->cwnd_inc_pct_ss*cc->cwnd/100);
+}
+
+/**
+ * Returns the amount to increment (and for Vegas, also decrement) the
+ * congestion window by, every update period.
+ *
+ * This is controlled by the cc_cwnd_inc consensus parameter.
+ */
+#define CWND_INC(cc) ((cc)->cwnd_inc)
+
+#endif /* !defined(CONGESTION_CONTROL_ST_H) */
diff --git a/src/core/or/include.am b/src/core/or/include.am
index b578b75673..6d2b73d03c 100644
--- a/src/core/or/include.am
+++ b/src/core/or/include.am
@@ -35,6 +35,7 @@ LIBTOR_APP_A_SOURCES += \
src/core/or/scheduler_kist.c \
src/core/or/scheduler_vanilla.c \
src/core/or/sendme.c \
+ src/core/or/sendme_common.c \
src/core/or/status.c \
src/core/or/versions.c
@@ -97,6 +98,7 @@ noinst_HEADERS += \
src/core/or/relay_crypto_st.h \
src/core/or/scheduler.h \
src/core/or/sendme.h \
+ src/core/or/sendme_common.h \
src/core/or/server_port_cfg_st.h \
src/core/or/socks_request_st.h \
src/core/or/status.h \
