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@@ -941,7 +941,11 @@ circuit_build_times_needs_circuits_now(circuit_build_times_t *cbt)
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}
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/**
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- * Called to indicate that the network showed some signs of liveness.
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+ * Called to indicate that the network showed some signs of liveness,
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+ * which means that we recieved a cell.
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+ *
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+ * This is used by circuit_build_times_network_check_live() to decide
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+ * if we should record the circuit build timeout or not.
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*
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* This function is called every time we receive a cell. Avoid
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* syscalls, events, and other high-intensity work.
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@@ -965,6 +969,10 @@ circuit_build_times_network_is_live(circuit_build_times_t *cbt)
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/**
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* Called to indicate that we completed a circuit. Because this circuit
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* succeeded, it doesn't count as a timeout-after-the-first-hop.
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+ *
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+ * This is used by circuit_build_times_network_check_changed() to determine
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+ * if we had too many recent timeouts and need to reset our learned timeout
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+ * to something higher.
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*/
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void
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circuit_build_times_network_circ_success(circuit_build_times_t *cbt)
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@@ -977,6 +985,10 @@ circuit_build_times_network_circ_success(circuit_build_times_t *cbt)
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/**
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* A circuit just timed out. If it failed after the first hop, record it
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* in our history for later deciding if the network speed has changed.
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+ *
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+ * This is used by circuit_build_times_network_check_changed() to determine
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+ * if we had too many recent timeouts and need to reset our learned timeout
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+ * to something higher.
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*/
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static void
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circuit_build_times_network_timeout(circuit_build_times_t *cbt,
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@@ -993,6 +1005,9 @@ circuit_build_times_network_timeout(circuit_build_times_t *cbt,
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* A circuit was just forcibly closed. If there has been no recent network
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* activity at all, but this circuit was launched back when we thought the
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* network was live, increment the number of "nonlive" circuit timeouts.
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+ *
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+ * This is used by circuit_build_times_network_check_live() to decide
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+ * if we should record the circuit build timeout or not.
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*/
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static void
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circuit_build_times_network_close(circuit_build_times_t *cbt,
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@@ -1032,8 +1047,11 @@ circuit_build_times_network_close(circuit_build_times_t *cbt,
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}
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/**
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- * Returns false if the network has not received a cell or tls handshake
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- * in the past NETWORK_NOTLIVE_TIMEOUT_COUNT circuits.
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+ * When the network is not live, we do not record circuit build times.
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+ *
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+ * The network is considered not live if there has been at least one
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+ * circuit build that began and ended (had its close_ms measurement
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+ * period expire) since we last recieved a cell.
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*
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* Also has the side effect of rewinding the circuit time history
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* in the case of recent liveness changes.
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@@ -1051,7 +1069,8 @@ circuit_build_times_network_check_live(circuit_build_times_t *cbt)
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/**
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* Returns true if we have seen more than MAX_RECENT_TIMEOUT_COUNT of
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* the past RECENT_CIRCUITS time out after the first hop. Used to detect
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- * if the network connection has changed significantly.
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+ * if the network connection has changed significantly, and if so,
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+ * resets our circuit build timeout to the default.
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*
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* Also resets the entire timeout history in this case and causes us
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* to restart the process of building test circuits and estimating a
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