net: make Ban/Unban/ClearBan functionality consistent

- Ban/Unban/ClearBan call uiInterface.BannedListChanged() as necessary
- Ban/Unban/ClearBan sync to disk if the operation is user-invoked
- Mark node for disconnection automatically when banning
- Lock cs_vNodes while setting disconnected
- Don't spin in a tight loop while setting disconnected

src/net.cpp

@@ -463,9 +463,13 @@ bool CNode::setBannedIsDirty;
 
 void CNode::ClearBanned()
 {
+    {
         LOCK(cs_setBanned);
         setBanned.clear();
         setBannedIsDirty = true;
+    }
+    DumpBanlist(); //store banlist to disk
+    uiInterface.BannedListChanged();
 }
 
 bool CNode::IsBanned(CNetAddr ip)
@@ -516,11 +520,25 @@ void CNode::Ban(const CSubNet& subNet, const BanReason &banReason, int64_t banti
     }
     banEntry.nBanUntil = (sinceUnixEpoch ? 0 : GetTime() )+bantimeoffset;
 
+    {
         LOCK(cs_setBanned);
-    if (setBanned[subNet].nBanUntil < banEntry.nBanUntil)
+        if (setBanned[subNet].nBanUntil < banEntry.nBanUntil) {
             setBanned[subNet] = banEntry;
-
             setBannedIsDirty = true;
+        }
+        else
+            return;
+    }
+    uiInterface.BannedListChanged();
+    {
+        LOCK(cs_vNodes);
+        BOOST_FOREACH(CNode* pnode, vNodes) {
+            if (subNet.Match((CNetAddr)pnode->addr))
+                pnode->fDisconnect = true;
+        }
+    }
+    if(banReason == BanReasonManuallyAdded)
+        DumpBanlist(); //store banlist to disk immediately if user requested ban
 }
 
 bool CNode::Unban(const CNetAddr &addr) {
@@ -529,13 +547,15 @@ bool CNode::Unban(const CNetAddr &addr) {
 }
 
 bool CNode::Unban(const CSubNet &subNet) {
-    LOCK(cs_setBanned);
-    if (setBanned.erase(subNet))
     {
-        setBannedIsDirty = true;
+        LOCK(cs_setBanned);
-        return true;
+        if (!setBanned.erase(subNet))
-    }
             return false;
+        setBannedIsDirty = true;
+    }
+    uiInterface.BannedListChanged();
+    DumpBanlist(); //store banlist to disk immediately
+    return true;
 }
 
 void CNode::GetBanned(banmap_t &banMap)

src/qt/rpcconsole.cpp

@@ -885,15 +885,13 @@ void RPCConsole::banSelectedNode(int bantime)
     // Get currently selected peer address
     QString strNode = GUIUtil::getEntryData(ui->peerWidget, 0, PeerTableModel::Address);
     // Find possible nodes, ban it and clear the selected node
-    if (CNode *bannedNode = FindNode(strNode.toStdString())) {
+    if (FindNode(strNode.toStdString())) {
         std::string nStr = strNode.toStdString();
         std::string addr;
         int port = 0;
         SplitHostPort(nStr, port, addr);
 
         CNode::Ban(CNetAddr(addr), BanReasonManuallyAdded, bantime);
-        bannedNode->fDisconnect = true;
-        DumpBanlist();
 
         clearSelectedNode();
         clientModel->getBanTableModel()->refresh();
@@ -912,7 +910,6 @@ void RPCConsole::unbanSelectedNode()
     if (possibleSubnet.IsValid())
     {
         CNode::Unban(possibleSubnet);
-        DumpBanlist();
         clientModel->getBanTableModel()->refresh();
     }
 }

src/rpc/net.cpp

@@ -565,20 +565,12 @@ UniValue setban(const UniValue& params, bool fHelp)
             absolute = true;
 
         isSubnet ? CNode::Ban(subNet, BanReasonManuallyAdded, banTime, absolute) : CNode::Ban(netAddr, BanReasonManuallyAdded, banTime, absolute);
-
-        //disconnect possible nodes
-        while(CNode *bannedNode = (isSubnet ? FindNode(subNet) : FindNode(netAddr)))
-            bannedNode->fDisconnect = true;
     }
     else if(strCommand == "remove")
     {
         if (!( isSubnet ? CNode::Unban(subNet) : CNode::Unban(netAddr) ))
             throw JSONRPCError(RPC_MISC_ERROR, "Error: Unban failed");
     }
-
-    DumpBanlist(); //store banlist to disk
-    uiInterface.BannedListChanged();
-
     return NullUniValue;
 }
 
@@ -624,8 +616,6 @@ UniValue clearbanned(const UniValue& params, bool fHelp)
                             );
 
     CNode::ClearBanned();
-    DumpBanlist(); //store banlist to disk
-    uiInterface.BannedListChanged();
 
     return NullUniValue;
 }