Make all Poisson delays use std::chrono types

Author: sipa

src/net.cpp

@@ -1761,12 +1761,11 @@ void CConnman::ThreadOpenConnections(const std::vector<std::string> connect)
     }
 
     // Initiate network connections
-    auto start = GetTime<std::chrono::seconds>();
+    auto start = GetTime<std::chrono::microseconds>();
 
     // Minimum time before next feeler connection (in microseconds).
-
-    int64_t nNextFeeler = PoissonNextSend(count_microseconds(start), FEELER_INTERVAL);
-    int64_t nNextExtraBlockRelay = PoissonNextSend(count_microseconds(start), EXTRA_BLOCK_RELAY_ONLY_PEER_INTERVAL);
+    auto next_feeler = PoissonNextSend(start, FEELER_INTERVAL);
+    auto next_extra_block_relay = PoissonNextSend(start, EXTRA_BLOCK_RELAY_ONLY_PEER_INTERVAL);
     const bool dnsseed = gArgs.GetBoolArg("-dnsseed", DEFAULT_DNSSEED);
     bool add_fixed_seeds = gArgs.GetBoolArg("-fixedseeds", DEFAULT_FIXEDSEEDS);
 
@@ -1849,7 +1848,7 @@ void CConnman::ThreadOpenConnections(const std::vector<std::string> connect)
         }
 
         ConnectionType conn_type = ConnectionType::OUTBOUND_FULL_RELAY;
-        int64_t nTime = GetTimeMicros();
+        auto now = GetTime<std::chrono::microseconds>();
         bool anchor = false;
         bool fFeeler = false;
 
@@ -1861,7 +1860,7 @@ void CConnman::ThreadOpenConnections(const std::vector<std::string> connect)
         // GetTryNewOutboundPeer() gets set when a stale tip is detected, so we
         // try opening an additional OUTBOUND_FULL_RELAY connection. If none of
         // these conditions are met, check to see if it's time to try an extra
-        // block-relay-only peer (to confirm our tip is current, see below) or the nNextFeeler
+        // block-relay-only peer (to confirm our tip is current, see below) or the next_feeler
         // timer to decide if we should open a FEELER.
 
         if (!m_anchors.empty() && (nOutboundBlockRelay < m_max_outbound_block_relay)) {
@@ -1873,7 +1872,7 @@ void CConnman::ThreadOpenConnections(const std::vector<std::string> connect)
             conn_type = ConnectionType::BLOCK_RELAY;
         } else if (GetTryNewOutboundPeer()) {
             // OUTBOUND_FULL_RELAY
-        } else if (nTime > nNextExtraBlockRelay && m_start_extra_block_relay_peers) {
+        } else if (now > next_extra_block_relay && m_start_extra_block_relay_peers) {
             // Periodically connect to a peer (using regular outbound selection
             // methodology from addrman) and stay connected long enough to sync
             // headers, but not much else.
@@ -1895,10 +1894,10 @@ void CConnman::ThreadOpenConnections(const std::vector<std::string> connect)
             // Because we can promote these connections to block-relay-only
             // connections, they do not get their own ConnectionType enum
             // (similar to how we deal with extra outbound peers).
-            nNextExtraBlockRelay = PoissonNextSend(nTime, EXTRA_BLOCK_RELAY_ONLY_PEER_INTERVAL);
+            next_extra_block_relay = PoissonNextSend(now, EXTRA_BLOCK_RELAY_ONLY_PEER_INTERVAL);
             conn_type = ConnectionType::BLOCK_RELAY;
-        } else if (nTime > nNextFeeler) {
-            nNextFeeler = PoissonNextSend(nTime, FEELER_INTERVAL);
+        } else if (now > next_feeler) {
+            next_feeler = PoissonNextSend(now, FEELER_INTERVAL);
             conn_type = ConnectionType::FEELER;
             fFeeler = true;
         } else {
@@ -2983,20 +2982,21 @@ bool CConnman::ForNode(NodeId id, std::function<bool(CNode* pnode)> func)
     return found != nullptr && NodeFullyConnected(found) && func(found);
 }
 
-int64_t CConnman::PoissonNextSendInbound(int64_t now, int average_interval_seconds)
+std::chrono::microseconds CConnman::PoissonNextSendInbound(std::chrono::microseconds now, std::chrono::seconds average_interval)
 {
-    if (m_next_send_inv_to_incoming < now) {
+    if (m_next_send_inv_to_incoming.load() < now) {
         // If this function were called from multiple threads simultaneously
         // it would possible that both update the next send variable, and return a different result to their caller.
         // This is not possible in practice as only the net processing thread invokes this function.
-        m_next_send_inv_to_incoming = PoissonNextSend(now, average_interval_seconds);
+        m_next_send_inv_to_incoming = PoissonNextSend(now, average_interval);
     }
     return m_next_send_inv_to_incoming;
 }
 
-int64_t PoissonNextSend(int64_t now, int average_interval_seconds)
+std::chrono::microseconds PoissonNextSend(std::chrono::microseconds now, std::chrono::seconds average_interval)
 {
-    return now + (int64_t)(log1p(GetRand(1ULL << 48) * -0.0000000000000035527136788 /* -1/2^48 */) * average_interval_seconds * -1000000.0 + 0.5);
+    double unscaled = -log1p(GetRand(1ULL << 48) * -0.0000000000000035527136788 /* -1/2^48 */);
+    return now + std::chrono::duration_cast<std::chrono::microseconds>(unscaled * average_interval + 0.5us);
 }
 
 CSipHasher CConnman::GetDeterministicRandomizer(uint64_t id) const

src/net.h

@@ -49,10 +49,10 @@ static const bool DEFAULT_WHITELISTFORCERELAY = false;
 
 /** Time after which to disconnect, after waiting for a ping response (or inactivity). */
 static const int TIMEOUT_INTERVAL = 20 * 60;
-/** Run the feeler connection loop once every 2 minutes or 120 seconds. **/
-static const int FEELER_INTERVAL = 120;
+/** Run the feeler connection loop once every 2 minutes. **/
+static constexpr auto FEELER_INTERVAL = 2min;
 /** Run the extra block-relay-only connection loop once every 5 minutes. **/
-static const int EXTRA_BLOCK_RELAY_ONLY_PEER_INTERVAL = 300;
+static constexpr auto EXTRA_BLOCK_RELAY_ONLY_PEER_INTERVAL = 5min;
 /** The maximum number of addresses from our addrman to return in response to a getaddr message. */
 static constexpr size_t MAX_ADDR_TO_SEND = 1000;
 /** Maximum length of incoming protocol messages (no message over 4 MB is currently acceptable). */
@@ -573,7 +573,7 @@ class CNode
         /** Minimum fee rate with which to filter inv's to this node */
         std::atomic<CAmount> minFeeFilter{0};
         CAmount lastSentFeeFilter{0};
-        int64_t nextSendTimeFeeFilter{0};
+        std::chrono::microseconds m_next_send_feefilter{0};
     };
 
     // m_tx_relay == nullptr if we're not relaying transactions with this peer
@@ -1021,7 +1021,7 @@ class CConnman
         Works assuming that a single interval is used.
         Variable intervals will result in privacy decrease.
     */
-    int64_t PoissonNextSendInbound(int64_t now, int average_interval_seconds);
+    std::chrono::microseconds PoissonNextSendInbound(std::chrono::microseconds now, std::chrono::seconds average_interval);
 
     void SetAsmap(std::vector<bool> asmap) { addrman.m_asmap = std::move(asmap); }
 
@@ -1256,7 +1256,7 @@ class CConnman
      */
     std::atomic_bool m_start_extra_block_relay_peers{false};
 
-    std::atomic<int64_t> m_next_send_inv_to_incoming{0};
+    std::atomic<std::chrono::microseconds> m_next_send_inv_to_incoming{0us};
 
     /**
      * A vector of -bind=<address>:<port>=onion arguments each of which is
@@ -1269,13 +1269,7 @@ class CConnman
 };
 
 /** Return a timestamp in the future (in microseconds) for exponentially distributed events. */
-int64_t PoissonNextSend(int64_t now, int average_interval_seconds);
-
-/** Wrapper to return mockable type */
-inline std::chrono::microseconds PoissonNextSend(std::chrono::microseconds now, std::chrono::seconds average_interval)
-{
-    return std::chrono::microseconds{PoissonNextSend(now.count(), average_interval.count())};
-}
+std::chrono::microseconds PoissonNextSend(std::chrono::microseconds now, std::chrono::seconds average_interval);
 
 /** Dump binary message to file, with timestamp */
 void CaptureMessage(const CAddress& addr, const std::string& msg_type, const Span<const unsigned char>& data, bool is_incoming);

src/net_processing.cpp

@@ -119,17 +119,21 @@ static const int MAX_UNCONNECTING_HEADERS = 10;
 /** Minimum blocks required to signal NODE_NETWORK_LIMITED */
 static const unsigned int NODE_NETWORK_LIMITED_MIN_BLOCKS = 288;
 /** Average delay between local address broadcasts */
-static constexpr std::chrono::hours AVG_LOCAL_ADDRESS_BROADCAST_INTERVAL{24};
+static constexpr auto AVG_LOCAL_ADDRESS_BROADCAST_INTERVAL = 24h;
 /** Average delay between peer address broadcasts */
-static constexpr std::chrono::seconds AVG_ADDRESS_BROADCAST_INTERVAL{30};
-/** Average delay between trickled inventory transmissions in seconds.
- *  Blocks and peers with noban permission bypass this, outbound peers get half this delay. */
-static const unsigned int INVENTORY_BROADCAST_INTERVAL = 5;
+static constexpr auto AVG_ADDRESS_BROADCAST_INTERVAL = 30s;
+/** Average delay between trickled inventory transmissions for inbound peers.
+ *  Blocks and peers with noban permission bypass this. */
+static constexpr auto INBOUND_INVENTORY_BROADCAST_INTERVAL = 5s;
+/** Average delay between trickled inventory transmissions for outbound peers.
+ *  Use a smaller delay as there is less privacy concern for them.
+ *  Blocks and peers with noban permission bypass this. */
+static constexpr auto OUTBOUND_INVENTORY_BROADCAST_INTERVAL = 2s;
 /** Maximum rate of inventory items to send per second.
  *  Limits the impact of low-fee transaction floods. */
 static constexpr unsigned int INVENTORY_BROADCAST_PER_SECOND = 7;
 /** Maximum number of inventory items to send per transmission. */
-static constexpr unsigned int INVENTORY_BROADCAST_MAX = INVENTORY_BROADCAST_PER_SECOND * INVENTORY_BROADCAST_INTERVAL;
+static constexpr unsigned int INVENTORY_BROADCAST_MAX = INVENTORY_BROADCAST_PER_SECOND * count_seconds(INBOUND_INVENTORY_BROADCAST_INTERVAL);
 /** The number of most recently announced transactions a peer can request. */
 static constexpr unsigned int INVENTORY_MAX_RECENT_RELAY = 3500;
 /** Verify that INVENTORY_MAX_RECENT_RELAY is enough to cache everything typically
@@ -138,9 +142,9 @@ static constexpr unsigned int INVENTORY_MAX_RECENT_RELAY = 3500;
  *  peers, and random variations in the broadcast mechanism. */
 static_assert(INVENTORY_MAX_RECENT_RELAY >= INVENTORY_BROADCAST_PER_SECOND * UNCONDITIONAL_RELAY_DELAY / std::chrono::seconds{1}, "INVENTORY_RELAY_MAX too low");
 /** Average delay between feefilter broadcasts in seconds. */
-static constexpr unsigned int AVG_FEEFILTER_BROADCAST_INTERVAL = 10 * 60;
+static constexpr auto AVG_FEEFILTER_BROADCAST_INTERVAL = 10min;
 /** Maximum feefilter broadcast delay after significant change. */
-static constexpr unsigned int MAX_FEEFILTER_CHANGE_DELAY = 5 * 60;
+static constexpr auto MAX_FEEFILTER_CHANGE_DELAY = 5min;
 /** Maximum number of compact filters that may be requested with one getcfilters. See BIP 157. */
 static constexpr uint32_t MAX_GETCFILTERS_SIZE = 1000;
 /** Maximum number of cf hashes that may be requested with one getcfheaders. See BIP 157. */
@@ -4669,10 +4673,9 @@ bool PeerManagerImpl::SendMessages(CNode* pto)
                 if (pto->m_tx_relay->nNextInvSend < current_time) {
                     fSendTrickle = true;
                     if (pto->IsInboundConn()) {
-                        pto->m_tx_relay->nNextInvSend = std::chrono::microseconds{m_connman.PoissonNextSendInbound(count_microseconds(current_time), INVENTORY_BROADCAST_INTERVAL)};
+                        pto->m_tx_relay->nNextInvSend = m_connman.PoissonNextSendInbound(current_time, INBOUND_INVENTORY_BROADCAST_INTERVAL);
                     } else {
-                        // Use half the delay for outbound peers, as there is less privacy concern for them.
-                        pto->m_tx_relay->nNextInvSend = PoissonNextSend(current_time, std::chrono::seconds{INVENTORY_BROADCAST_INTERVAL >> 1});
+                        pto->m_tx_relay->nNextInvSend = PoissonNextSend(current_time, OUTBOUND_INVENTORY_BROADCAST_INTERVAL);
                     }
                 }
 
@@ -4927,24 +4930,24 @@ bool PeerManagerImpl::SendMessages(CNode* pto)
                 if (pto->m_tx_relay->lastSentFeeFilter == MAX_FILTER) {
                     // Send the current filter if we sent MAX_FILTER previously
                     // and made it out of IBD.
-                    pto->m_tx_relay->nextSendTimeFeeFilter = count_microseconds(current_time) - 1;
+                    pto->m_tx_relay->m_next_send_feefilter = 0us;
                 }
             }
-            if (count_microseconds(current_time) > pto->m_tx_relay->nextSendTimeFeeFilter) {
+            if (current_time > pto->m_tx_relay->m_next_send_feefilter) {
                 CAmount filterToSend = g_filter_rounder.round(currentFilter);
                 // We always have a fee filter of at least minRelayTxFee
                 filterToSend = std::max(filterToSend, ::minRelayTxFee.GetFeePerK());
                 if (filterToSend != pto->m_tx_relay->lastSentFeeFilter) {
                     m_connman.PushMessage(pto, msgMaker.Make(NetMsgType::FEEFILTER, filterToSend));
                     pto->m_tx_relay->lastSentFeeFilter = filterToSend;
                 }
-                pto->m_tx_relay->nextSendTimeFeeFilter = PoissonNextSend(count_microseconds(current_time), AVG_FEEFILTER_BROADCAST_INTERVAL);
+                pto->m_tx_relay->m_next_send_feefilter = PoissonNextSend(current_time, AVG_FEEFILTER_BROADCAST_INTERVAL);
             }
             // If the fee filter has changed substantially and it's still more than MAX_FEEFILTER_CHANGE_DELAY
             // until scheduled broadcast, then move the broadcast to within MAX_FEEFILTER_CHANGE_DELAY.
-            else if (count_microseconds(current_time) + MAX_FEEFILTER_CHANGE_DELAY * 1000000 < pto->m_tx_relay->nextSendTimeFeeFilter &&
+            else if (current_time + MAX_FEEFILTER_CHANGE_DELAY < pto->m_tx_relay->m_next_send_feefilter &&
                      (currentFilter < 3 * pto->m_tx_relay->lastSentFeeFilter / 4 || currentFilter > 4 * pto->m_tx_relay->lastSentFeeFilter / 3)) {
-                pto->m_tx_relay->nextSendTimeFeeFilter = count_microseconds(current_time) + GetRandInt(MAX_FEEFILTER_CHANGE_DELAY) * 1000000;
+                pto->m_tx_relay->m_next_send_feefilter = current_time + GetRandomDuration<std::chrono::microseconds>(MAX_FEEFILTER_CHANGE_DELAY);
             }
         }
     } // release cs_main

src/test/fuzz/connman.cpp

@@ -104,7 +104,9 @@ FUZZ_TARGET_INIT(connman, initialize_connman)
             },
             [&] {
                 // Limit now to int32_t to avoid signed integer overflow
-                (void)connman.PoissonNextSendInbound(fuzzed_data_provider.ConsumeIntegral<int32_t>(), fuzzed_data_provider.ConsumeIntegral<int>());
+                (void)connman.PoissonNextSendInbound(
+                        std::chrono::microseconds{fuzzed_data_provider.ConsumeIntegral<int32_t>()},
+                        std::chrono::seconds{fuzzed_data_provider.ConsumeIntegral<int>()});
             },
             [&] {
                 CSerializedNetMsg serialized_net_msg;

src/test/net_tests.cpp

@@ -803,21 +803,6 @@ BOOST_AUTO_TEST_CASE(LocalAddress_BasicLifecycle)
     BOOST_CHECK_EQUAL(IsLocal(addr), false);
 }
 
-BOOST_AUTO_TEST_CASE(PoissonNextSend)
-{
-    g_mock_deterministic_tests = true;
-
-    int64_t now = 5000;
-    int average_interval_seconds = 600;
-
-    auto poisson = ::PoissonNextSend(now, average_interval_seconds);
-    std::chrono::microseconds poisson_chrono = ::PoissonNextSend(std::chrono::microseconds{now}, std::chrono::seconds{average_interval_seconds});
-
-    BOOST_CHECK_EQUAL(poisson, poisson_chrono.count());
-
-    g_mock_deterministic_tests = false;
-}
-
 std::vector<NodeEvictionCandidate> GetRandomNodeEvictionCandidates(const int n_candidates, FastRandomContext& random_context)
 {
     std::vector<NodeEvictionCandidate> candidates;

src/util/time.h

@@ -26,9 +26,9 @@ void UninterruptibleSleep(const std::chrono::microseconds& n);
  * This helper is used to convert durations before passing them over an
  * interface that doesn't support std::chrono (e.g. RPC, debug log, or the GUI)
  */
-inline int64_t count_seconds(std::chrono::seconds t) { return t.count(); }
-inline int64_t count_milliseconds(std::chrono::milliseconds t) { return t.count(); }
-inline int64_t count_microseconds(std::chrono::microseconds t) { return t.count(); }
+constexpr int64_t count_seconds(std::chrono::seconds t) { return t.count(); }
+constexpr int64_t count_milliseconds(std::chrono::milliseconds t) { return t.count(); }
+constexpr int64_t count_microseconds(std::chrono::microseconds t) { return t.count(); }
 
 using SecondsDouble = std::chrono::duration<double, std::chrono::seconds::period>;