1 files changed, 18 insertions, 4 deletions
diff --git a/src/net.cpp b/src/net.cpp
index 4bf7e71729..d52d5b7cf5 100644
--- a/src/net.cpp
+++ b/src/net.cpp
@@ -163,8 +163,7 @@ CAddress GetLocalAddress(const CNetAddr *paddrPeer, ServiceFlags nLocalServices)
 static int GetnScore(const CService& addr)
 {
     LOCK(cs_mapLocalHost);
-    if (mapLocalHost.count(addr) == LOCAL_NONE)
-        return 0;
+    if (mapLocalHost.count(addr) == 0) return 0;
     return mapLocalHost[addr].nScore;
 }
 
@@ -753,6 +752,7 @@ struct NodeEvictionCandidate
     bool fBloomFilter;
     CAddress addr;
     uint64_t nKeyedNetGroup;
+    bool prefer_evict;
 };
 
 static bool ReverseCompareNodeMinPingTime(const NodeEvictionCandidate &a, const NodeEvictionCandidate &b)
@@ -821,7 +821,8 @@ bool CConnman::AttemptToEvictConnection()
             NodeEvictionCandidate candidate = {node->GetId(), node->nTimeConnected, node->nMinPingUsecTime,
                                                node->nLastBlockTime, node->nLastTXTime,
                                                HasAllDesirableServiceFlags(node->nServices),
-                                               node->fRelayTxes, node->pfilter != nullptr, node->addr, node->nKeyedNetGroup};
+                                               node->fRelayTxes, node->pfilter != nullptr, node->addr, node->nKeyedNetGroup,
+                                               node->m_prefer_evict};
             vEvictionCandidates.push_back(candidate);
         }
     }
@@ -846,6 +847,14 @@ bool CConnman::AttemptToEvictConnection()
 
     if (vEvictionCandidates.empty()) return false;
 
+    // If any remaining peers are preferred for eviction consider only them.
+    // This happens after the other preferences since if a peer is really the best by other criteria (esp relaying blocks)
+    //  then we probably don't want to evict it no matter what.
+    if (std::any_of(vEvictionCandidates.begin(),vEvictionCandidates.end(),[](NodeEvictionCandidate const &n){return n.prefer_evict;})) {
+        vEvictionCandidates.erase(std::remove_if(vEvictionCandidates.begin(),vEvictionCandidates.end(),
+                                  [](NodeEvictionCandidate const &n){return !n.prefer_evict;}),vEvictionCandidates.end());
+    }
+
     // Identify the network group with the most connections and youngest member.
     // (vEvictionCandidates is already sorted by reverse connect time)
     uint64_t naMostConnections;
@@ -926,7 +935,11 @@ void CConnman::AcceptConnection(const ListenSocket& hListenSocket) {
     // on all platforms.  Set it again here just to be sure.
     SetSocketNoDelay(hSocket);
 
-    if (m_banman && m_banman->IsBanned(addr) && !whitelisted)
+    int bannedlevel = m_banman ? m_banman->IsBannedLevel(addr) : 0;
+
+    // Don't accept connections from banned peers, but if our inbound slots aren't almost full, accept
+    // if the only banning reason was an automatic misbehavior ban.
+    if (!whitelisted && bannedlevel > ((nInbound + 1 < nMaxInbound) ? 1 : 0))
     {
         LogPrint(BCLog::NET, "connection from %s dropped (banned)\n", addr.ToString());
         CloseSocket(hSocket);
@@ -950,6 +963,7 @@ void CConnman::AcceptConnection(const ListenSocket& hListenSocket) {
     CNode* pnode = new CNode(id, nLocalServices, GetBestHeight(), hSocket, addr, CalculateKeyedNetGroup(addr), nonce, addr_bind, "", true);
     pnode->AddRef();
     pnode->fWhitelisted = whitelisted;
+    pnode->m_prefer_evict = bannedlevel > 0;
     m_msgproc->InitializeNode(pnode);
 
     LogPrint(BCLog::NET, "connection from %s accepted\n", addr.ToString());