From b105ba398b20789eb482e45f26ae1761800b81be Mon Sep 17 00:00:00 2001
From: Patrick Strateman <patrick.strateman@gmail.com>
Date: Thu, 13 Aug 2015 17:22:35 -0700
Subject: [PATCH] Prefer to disconnect peers in favor of whitelisted peers

---
 src/net.cpp | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/net.cpp b/src/net.cpp
index 0fab0f82a..77dde9944 100644
--- a/src/net.cpp
+++ b/src/net.cpp
@@ -818,7 +818,7 @@ public:
     }
 };
 
-static bool AttemptToEvictConnection() {
+static bool AttemptToEvictConnection(bool fPreferNewConnection) {
     std::vector<CNode*> vEvictionCandidates;
     {
         LOCK(cs_vNodes);
@@ -866,8 +866,11 @@ static bool AttemptToEvictConnection() {
     // Reduce to the CNetAddr with the most connections
     vEvictionCandidates = mapAddrCounts[naMostConnections];
 
+    // Do not disconnect peers who have only 1 evictable connection
     if (vEvictionCandidates.size() <= 1)
-        return false;
+        // unless we prefer the new connection (for whitelisted peers)
+        if (!fPreferNewConnection)
+            return false;
 
     // Disconnect the most recent connection from the CNetAddr with the most connections
     std::sort(vEvictionCandidates.begin(), vEvictionCandidates.end(), ReverseCompareNodeTimeConnected);
@@ -920,7 +923,7 @@ static void AcceptConnection(const ListenSocket& hListenSocket) {
 
     if (nInbound >= nMaxInbound)
     {
-        if (!AttemptToEvictConnection()) {
+        if (!AttemptToEvictConnection(whitelisted)) {
             // No connection to evict, disconnect the new connection
             LogPrint("net", "failed to find an eviction candidate - connection dropped (full)\n");
             CloseSocket(hSocket);