Don't exclusively drop tor/i2p outgoing cxns in idle loop

src/cryptonote_protocol/cryptonote_protocol_handler.h

@@ -113,12 +113,23 @@ namespace cryptonote
     const block_queue &get_block_queue() const { return m_block_queue; }
     void stop();
     void on_connection_close(cryptonote_connection_context &context);
-    void set_max_out_peers(unsigned int max) { m_max_out_peers = max; }
+    void set_max_out_peers(epee::net_utils::zone zone, unsigned int max) { CRITICAL_REGION_LOCAL(m_max_out_peers_lock); m_max_out_peers[zone] = max; }
+    unsigned int get_max_out_peers(epee::net_utils::zone zone) const
+    {
+      CRITICAL_REGION_LOCAL(m_max_out_peers_lock);
+      const auto it = m_max_out_peers.find(zone);
+      if (it == m_max_out_peers.end())
+      {
+        MWARNING(epee::net_utils::zone_to_string(zone) << " max out peers not set, using default");
+        return P2P_DEFAULT_CONNECTIONS_COUNT;
+      }
+      return it->second;
+    }
     bool no_sync() const { return m_no_sync; }
     void set_no_sync(bool value) { m_no_sync = value; }
     std::string get_peers_overview() const;
     std::pair<uint32_t, uint32_t> get_next_needed_pruning_stripe() const;
-    bool needs_new_sync_connections() const;
+    bool needs_new_sync_connections(epee::net_utils::zone zone) const;
     bool is_busy_syncing();
 
   private:
@@ -171,7 +182,8 @@ namespace cryptonote
     epee::math_helper::once_a_time_milliseconds<100> m_standby_checker;
     epee::math_helper::once_a_time_seconds<101> m_sync_search_checker;
     epee::math_helper::once_a_time_seconds<43> m_bad_peer_checker;
-    std::atomic<unsigned int> m_max_out_peers;
+    std::unordered_map<epee::net_utils::zone, unsigned int> m_max_out_peers;
+    mutable epee::critical_section m_max_out_peers_lock;
     tools::PerformanceTimer m_sync_timer, m_add_timer;
     uint64_t m_last_add_end_time;
     uint64_t m_sync_spans_downloaded, m_sync_old_spans_downloaded, m_sync_bad_spans_downloaded;

src/cryptonote_protocol/cryptonote_protocol_handler.inl

@@ -1776,33 +1776,49 @@ skip:
       return true;
 
     MTRACE("Checking for outgoing syncing peers...");
-    unsigned n_syncing = 0, n_synced = 0;
-    boost::uuids::uuid last_synced_peer_id(boost::uuids::nil_uuid());
+    std::unordered_map<epee::net_utils::zone, unsigned> n_syncing, n_synced;
+    std::unordered_map<epee::net_utils::zone, boost::uuids::uuid> last_synced_peer_id;
+    std::vector<epee::net_utils::zone> zones;
     m_p2p->for_each_connection([&](cryptonote_connection_context& context, nodetool::peerid_type peer_id, uint32_t support_flags)->bool
     {
       if (!peer_id || context.m_is_income) // only consider connected outgoing peers
         return true;
+
+      const epee::net_utils::zone zone = context.m_remote_address.get_zone();
+      if (n_syncing.find(zone) == n_syncing.end())
+      {
+        n_syncing[zone] = 0;
+        n_synced[zone] = 0;
+        last_synced_peer_id[zone] = boost::uuids::nil_uuid();
+        zones.push_back(zone);
+      }
+
       if (context.m_state == cryptonote_connection_context::state_synchronizing)
-        ++n_syncing;
+        ++n_syncing[zone];
       if (context.m_state == cryptonote_connection_context::state_normal)
       {
-        ++n_synced;
+        ++n_synced[zone];
         if (!context.m_anchor)
-          last_synced_peer_id = context.m_connection_id;
+          last_synced_peer_id[zone] = context.m_connection_id;
       }
       return true;
     });
-    MTRACE(n_syncing << " syncing, " << n_synced << " synced");
 
-    // if we're at max out peers, and not enough are syncing
-    if (n_synced + n_syncing >= m_max_out_peers && n_syncing < P2P_DEFAULT_SYNC_SEARCH_CONNECTIONS_COUNT && last_synced_peer_id != boost::uuids::nil_uuid())
+    for (const auto& zone : zones)
     {
-      if (!m_p2p->for_connection(last_synced_peer_id, [&](cryptonote_connection_context& ctx, nodetool::peerid_type peer_id, uint32_t f)->bool{
-        MINFO(ctx << "dropping synced peer, " << n_syncing << " syncing, " << n_synced << " synced");
-        drop_connection(ctx, false, false);
-        return true;
-      }))
-        MDEBUG("Failed to find peer we wanted to drop");
+      const unsigned int max_out_peers = get_max_out_peers(zone);
+      MTRACE("[" << epee::net_utils::zone_to_string(zone) << "] " << n_syncing[zone] << " syncing, " << n_synced[zone] << " synced, " << max_out_peers << " max out peers");
+
+      // if we're at max out peers, and not enough are syncing, drop the last sync'd non-anchor
+      if (n_synced[zone] + n_syncing[zone] >= max_out_peers && n_syncing[zone] < P2P_DEFAULT_SYNC_SEARCH_CONNECTIONS_COUNT && last_synced_peer_id[zone] != boost::uuids::nil_uuid())
+      {
+        if (!m_p2p->for_connection(last_synced_peer_id[zone], [&](cryptonote_connection_context& ctx, nodetool::peerid_type peer_id, uint32_t f)->bool{
+          MINFO(ctx << "dropping synced peer, " << n_syncing[zone] << " syncing, " << n_synced[zone] << " synced, " << max_out_peers << " max out peers");
+          drop_connection(ctx, false, false);
+          return true;
+        }))
+          MDEBUG("Failed to find peer we wanted to drop");
+      }
     }
 
     return true;
@@ -1987,11 +2003,13 @@ skip:
           ++n_peers_on_next_stripe;
         return true;
       });
+      // TODO: investigate tallying by zone and comparing to max out peers by zone
+      const unsigned int max_out_peers = get_max_out_peers(epee::net_utils::zone::public_);
       const uint32_t distance = (peer_stripe + (1<<CRYPTONOTE_PRUNING_LOG_STRIPES) - next_stripe) % (1<<CRYPTONOTE_PRUNING_LOG_STRIPES);
-      if ((n_out_peers >= m_max_out_peers && n_peers_on_next_stripe == 0) || (distance > 1 && n_peers_on_next_stripe <= 2) || distance > 2)
+      if ((n_out_peers >= max_out_peers && n_peers_on_next_stripe == 0) || (distance > 1 && n_peers_on_next_stripe <= 2) || distance > 2)
       {
         MDEBUG(context << "we want seed " << next_stripe << ", and either " << n_out_peers << " is at max out peers ("
-            << m_max_out_peers << ") or distance " << distance << " from " << next_stripe << " to " << peer_stripe <<
+            << max_out_peers << ") or distance " << distance << " from " << next_stripe << " to " << peer_stripe <<
             " is too large and we have only " << n_peers_on_next_stripe << " peers on next seed, dropping connection to make space");
         return true;
       }
@@ -2812,31 +2830,33 @@ skip:
       }
       return true;
     });
-    const bool use_next = (n_next > m_max_out_peers / 2 && n_subsequent <= 1) || (n_next > 2 && n_subsequent == 0);
+    // TODO: investigate tallying by zone and comparing to max out peers by zone
+    const unsigned int max_out_peers = get_max_out_peers(epee::net_utils::zone::public_);
+    const bool use_next = (n_next > max_out_peers / 2 && n_subsequent <= 1) || (n_next > 2 && n_subsequent == 0);
     const uint32_t ret_stripe = use_next ? subsequent_pruning_stripe: next_pruning_stripe;
     MIDEBUG(const std::string po = get_peers_overview(), "get_next_needed_pruning_stripe: want height " << want_height << " (" <<
         want_height_from_blockchain << " from blockchain, " << want_height_from_block_queue << " from block queue), stripe " <<
-        next_pruning_stripe << " (" << n_next << "/" << m_max_out_peers << " on it and " << n_subsequent << " on " <<
+        next_pruning_stripe << " (" << n_next << "/" << max_out_peers << " on it and " << n_subsequent << " on " <<
         subsequent_pruning_stripe << ", " << n_others << " others) -> " << ret_stripe << " (+" <<
         (ret_stripe - next_pruning_stripe + (1 << CRYPTONOTE_PRUNING_LOG_STRIPES)) % (1 << CRYPTONOTE_PRUNING_LOG_STRIPES) <<
         "), current peers " << po);
     return std::make_pair(next_pruning_stripe, ret_stripe);
   }
   //------------------------------------------------------------------------------------------------------------------------
   template<class t_core>
-  bool t_cryptonote_protocol_handler<t_core>::needs_new_sync_connections() const
+  bool t_cryptonote_protocol_handler<t_core>::needs_new_sync_connections(epee::net_utils::zone zone) const
   {
     const uint64_t target = m_core.get_target_blockchain_height();
     const uint64_t height = m_core.get_current_blockchain_height();
     if (target && target <= height)
       return false;
     size_t n_out_peers = 0;
     m_p2p->for_each_connection([&](cryptonote_connection_context& ctx, nodetool::peerid_type peer_id, uint32_t support_flags)->bool{
-      if (!ctx.m_is_income)
+      if (!ctx.m_is_income && ctx.m_remote_address.get_zone() == zone)
         ++n_out_peers;
       return true;
     });
-    if (n_out_peers >= m_max_out_peers)
+    if (n_out_peers >= get_max_out_peers(zone))
       return false;
     return true;
   }

src/p2p/net_node.inl

@@ -538,7 +538,7 @@ namespace nodetool
     if ( !set_max_out_peers(public_zone, command_line::get_arg(vm, arg_out_peers) ) )
       return false;
     else
-      m_payload_handler.set_max_out_peers(public_zone.m_config.m_net_config.max_out_connection_count);
+      m_payload_handler.set_max_out_peers(epee::net_utils::zone::public_, public_zone.m_config.m_net_config.max_out_connection_count);
 
 
     if ( !set_max_in_peers(public_zone, command_line::get_arg(vm, arg_in_peers) ) )
@@ -575,6 +575,8 @@ namespace nodetool
 
       if (!set_max_out_peers(zone, proxy.max_connections))
         return false;
+      else
+        m_payload_handler.set_max_out_peers(proxy.zone, proxy.max_connections);
 
       epee::byte_slice this_noise = nullptr;
       if (proxy.noise)
@@ -2758,7 +2760,7 @@ namespace nodetool
       public_zone->second.m_config.m_net_config.max_out_connection_count = count;
       if(current > count)
         public_zone->second.m_net_server.get_config_object().del_out_connections(current - count);
-      m_payload_handler.set_max_out_peers(count);
+      m_payload_handler.set_max_out_peers(epee::net_utils::zone::public_, count);
     }
   }
 
@@ -2887,10 +2889,12 @@ namespace nodetool
   {
     if (m_offline) return true;
     if (!m_exclusive_peers.empty()) return true;
-    if (m_payload_handler.needs_new_sync_connections()) return true;
 
     for (auto& zone : m_network_zones)
     {
+      if (m_payload_handler.needs_new_sync_connections(zone.first))
+        continue;
+
       if (zone.second.m_net_server.is_stop_signal_sent())
         return false;
 

tests/unit_tests/node_server.cpp

@@ -1026,12 +1026,12 @@ TEST(node_server, race_condition)
     }
     void stop() {}
     void on_connection_close(context_t &context) {}
-    void set_max_out_peers(unsigned int max) {}
+    void set_max_out_peers(epee::net_utils::zone zone, unsigned int max) {}
     bool no_sync() const { return {}; }
     void set_no_sync(bool value) {}
     string_t get_peers_overview() const { return {}; }
     stripes_t get_next_needed_pruning_stripe() const { return {}; }
-    bool needs_new_sync_connections() const { return {}; }
+    bool needs_new_sync_connections(epee::net_utils::zone zone) const { return {}; }
     bool is_busy_syncing() { return {}; }
   };
   using node_server_t = nodetool::node_server<protocol_t>;