[net] Add connection type to NodeEvictionCandidate

Author: dergoegge

Diff for: src/net.cpp

@@ -957,6 +957,15 @@ void ProtectNoBanConnections(std::vector<NodeEvictionCandidate>& eviction_candid
                               eviction_candidates.end());
 }
 
+void ProtectOutboundConnections(std::vector<NodeEvictionCandidate>& eviction_candidates)
+{
+    eviction_candidates.erase(std::remove_if(eviction_candidates.begin(), eviction_candidates.end(),
+                                             [](NodeEvictionCandidate const& n) {
+                                                 return n.m_conn_type != ConnectionType::INBOUND;
+                                             }),
+                              eviction_candidates.end());
+}
+
 void ProtectEvictionCandidatesByRatio(std::vector<NodeEvictionCandidate>& eviction_candidates)
 {
     // Protect the half of the remaining nodes which have been connected the longest.
@@ -1036,6 +1045,8 @@ void ProtectEvictionCandidatesByRatio(std::vector<NodeEvictionCandidate>& evicti
 
     ProtectNoBanConnections(vEvictionCandidates);
 
+    ProtectOutboundConnections(vEvictionCandidates);
+
     // Deterministically select 4 peers to protect by netgroup.
     // An attacker cannot predict which netgroups will be protected
     EraseLastKElements(vEvictionCandidates, CompareNetGroupKeyed, 4);
@@ -1107,8 +1118,6 @@ bool CConnman::AttemptToEvictConnection()
 
         LOCK(m_nodes_mutex);
         for (const CNode* node : m_nodes) {
-            if (!node->IsInboundConn())
-                continue;
             if (node->fDisconnect)
                 continue;
             NodeEvictionCandidate candidate{
@@ -1125,6 +1134,7 @@ bool CConnman::AttemptToEvictConnection()
                 Desig(m_is_local) node->addr.IsLocal(),
                 Desig(m_network) node->ConnectedThroughNetwork(),
                 Desig(m_noban) node->HasPermission(NetPermissionFlags::NoBan),
+                Desig(m_conn_type) node->m_conn_type,
             };
             vEvictionCandidates.push_back(candidate);
         }

Diff for: src/net.h

@@ -1262,6 +1262,7 @@ struct NodeEvictionCandidate
     bool m_is_local;
     Network m_network;
     bool m_noban;
+    ConnectionType m_conn_type;
 };
 
 /**

Diff for: src/test/fuzz/node_eviction.cpp

@@ -33,6 +33,7 @@ FUZZ_TARGET(node_eviction)
             /*m_is_local=*/fuzzed_data_provider.ConsumeBool(),
             /*m_network=*/fuzzed_data_provider.PickValueInArray(ALL_NETWORKS),
             /*m_noban=*/fuzzed_data_provider.ConsumeBool(),
+            /*m_conn_type=*/fuzzed_data_provider.PickValueInArray(ALL_CONNECTION_TYPES),
         });
     }
     // Make a copy since eviction_candidates may be in some valid but otherwise

Diff for: src/test/util/net.cpp

@@ -59,6 +59,7 @@ std::vector<NodeEvictionCandidate> GetRandomNodeEvictionCandidates(int n_candida
             /*m_is_local=*/random_context.randbool(),
             /*m_network=*/ALL_NETWORKS[random_context.randrange(ALL_NETWORKS.size())],
             /*m_noban=*/false,
+            /*m_conn_type=*/ConnectionType::INBOUND,
         });
     }
     return candidates;