Avoid counting failed connect attempts when probably offline.

If a node is offline failed outbound connection attempts will crank up
 the addrman counter and effectively blow away our state.

This change reduces the problem by only counting attempts made while
 the node believes it has outbound connections to at least two
 netgroups.

Connect and addnode connections are also not counted, as there is no
 reason to unequally penalize them for their more frequent
 connections -- though there should be no real effect from this
 unless their addnode configureation is later removed.

Wasteful repeated connection attempts while only a few connections are
 up are avoided via nLastTry.

This is still somewhat incomplete protection because our outbound
 peers could be down but not timed out or might all be on 'local'
 networks (although the requirement for multiple netgroups helps).

src/addrman.cpp

@@ -311,7 +311,7 @@ bool CAddrMan::Add_(const CAddress& addr, const CNetAddr& source, int64_t nTimeP
     return fNew;
 }
 
-void CAddrMan::Attempt_(const CService& addr, int64_t nTime)
+void CAddrMan::Attempt_(const CService& addr, bool fCountFailure, int64_t nTime)
 {
     CAddrInfo* pinfo = Find(addr);
 
@@ -327,7 +327,7 @@ void CAddrMan::Attempt_(const CService& addr, int64_t nTime)
 
     // update info
     info.nLastTry = nTime;
-    info.nAttempts++;
+    if (fCountFailure) info.nAttempts++;
 }
 
 CAddrInfo CAddrMan::Select_(bool newOnly)

src/addrman.h

@@ -230,7 +230,7 @@ class CAddrMan
     bool Add_(const CAddress &addr, const CNetAddr& source, int64_t nTimePenalty);
 
     //! Mark an entry as attempted to connect.
-    void Attempt_(const CService &addr, int64_t nTime);
+    void Attempt_(const CService &addr, bool fCountFailure, int64_t nTime);
 
     //! Select an address to connect to, if newOnly is set to true, only the new table is selected from.
     CAddrInfo Select_(bool newOnly);
@@ -532,12 +532,12 @@ class CAddrMan
     }
 
     //! Mark an entry as connection attempted to.
-    void Attempt(const CService &addr, int64_t nTime = GetAdjustedTime())
+    void Attempt(const CService &addr, bool fCountFailure, int64_t nTime = GetAdjustedTime())
     {
         {
             LOCK(cs);
             Check();
-            Attempt_(addr, nTime);
+            Attempt_(addr, fCountFailure, nTime);
             Check();
         }
     }

src/net.cpp

@@ -367,7 +367,7 @@ CNode* FindNode(const CService& addr)
     return NULL;
 }
 
-CNode* ConnectNode(CAddress addrConnect, const char *pszDest)
+CNode* ConnectNode(CAddress addrConnect, const char *pszDest, bool fCountFailure)
 {
     if (pszDest == NULL) {
         if (IsLocal(addrConnect))
@@ -399,7 +399,7 @@ CNode* ConnectNode(CAddress addrConnect, const char *pszDest)
             return NULL;
         }
 
-        addrman.Attempt(addrConnect);
+        addrman.Attempt(addrConnect, fCountFailure);
 
         // Add node
         CNode* pnode = new CNode(hSocket, addrConnect, pszDest ? pszDest : "", false);
@@ -416,7 +416,7 @@ CNode* ConnectNode(CAddress addrConnect, const char *pszDest)
     } else if (!proxyConnectionFailed) {
         // If connecting to the node failed, and failure is not caused by a problem connecting to
         // the proxy, mark this as an attempt.
-        addrman.Attempt(addrConnect);
+        addrman.Attempt(addrConnect, fCountFailure);
     }
 
     return NULL;
@@ -1533,7 +1533,7 @@ void static ProcessOneShot()
     CAddress addr;
     CSemaphoreGrant grant(*semOutbound, true);
     if (grant) {
-        if (!OpenNetworkConnection(addr, &grant, strDest.c_str(), true))
+        if (!OpenNetworkConnection(addr, false, &grant, strDest.c_str(), true))
             AddOneShot(strDest);
     }
 }
@@ -1549,7 +1549,7 @@ void ThreadOpenConnections()
             BOOST_FOREACH(const std::string& strAddr, mapMultiArgs["-connect"])
             {
                 CAddress addr;
-                OpenNetworkConnection(addr, NULL, strAddr.c_str());
+                OpenNetworkConnection(addr, false, NULL, strAddr.c_str());
                 for (int i = 0; i < 10 && i < nLoop; i++)
                 {
                     MilliSleep(500);
@@ -1633,7 +1633,7 @@ void ThreadOpenConnections()
         }
 
         if (addrConnect.IsValid())
-            OpenNetworkConnection(addrConnect, &grant);
+            OpenNetworkConnection(addrConnect, (int)setConnected.size() >= min(nMaxConnections - 1, 2), &grant);
     }
 }
 
@@ -1655,7 +1655,7 @@ void ThreadOpenAddedConnections()
             BOOST_FOREACH(const std::string& strAddNode, lAddresses) {
                 CAddress addr;
                 CSemaphoreGrant grant(*semOutbound);
-                OpenNetworkConnection(addr, &grant, strAddNode.c_str());
+                OpenNetworkConnection(addr, false, &grant, strAddNode.c_str());
                 MilliSleep(500);
             }
             MilliSleep(120000); // Retry every 2 minutes
@@ -1694,15 +1694,15 @@ void ThreadOpenAddedConnections()
         BOOST_FOREACH(std::vector<CService>& vserv, lservAddressesToAdd)
         {
             CSemaphoreGrant grant(*semOutbound);
-            OpenNetworkConnection(CAddress(vserv[i % vserv.size()]), &grant);
+            OpenNetworkConnection(CAddress(vserv[i % vserv.size()]), false, &grant);
             MilliSleep(500);
         }
         MilliSleep(120000); // Retry every 2 minutes
     }
 }
 
 // if successful, this moves the passed grant to the constructed node
-bool OpenNetworkConnection(const CAddress& addrConnect, CSemaphoreGrant *grantOutbound, const char *pszDest, bool fOneShot)
+bool OpenNetworkConnection(const CAddress& addrConnect, bool fCountFailure, CSemaphoreGrant *grantOutbound, const char *pszDest, bool fOneShot)
 {
     //
     // Initiate outbound network connection
@@ -1716,7 +1716,7 @@ bool OpenNetworkConnection(const CAddress& addrConnect, CSemaphoreGrant *grantOu
     } else if (FindNode(std::string(pszDest)))
         return false;
 
-    CNode* pnode = ConnectNode(addrConnect, pszDest);
+    CNode* pnode = ConnectNode(addrConnect, pszDest, fCountFailure);
     boost::this_thread::interruption_point();
 
     if (!pnode)

src/net.h

@@ -83,7 +83,7 @@ CNode* FindNode(const CNetAddr& ip);
 CNode* FindNode(const CSubNet& subNet);
 CNode* FindNode(const std::string& addrName);
 CNode* FindNode(const CService& ip);
-bool OpenNetworkConnection(const CAddress& addrConnect, CSemaphoreGrant *grantOutbound = NULL, const char *strDest = NULL, bool fOneShot = false);
+bool OpenNetworkConnection(const CAddress& addrConnect, bool fCountFailure, CSemaphoreGrant *grantOutbound = NULL, const char *strDest = NULL, bool fOneShot = false);
 void MapPort(bool fUseUPnP);
 unsigned short GetListenPort();
 bool BindListenPort(const CService &bindAddr, std::string& strError, bool fWhitelisted = false);

src/rpc/net.cpp

@@ -219,7 +219,7 @@ UniValue addnode(const UniValue& params, bool fHelp)
     if (strCommand == "onetry")
     {
         CAddress addr;
-        OpenNetworkConnection(addr, NULL, strNode.c_str());
+        OpenNetworkConnection(addr, false, NULL, strNode.c_str());
         return NullUniValue;
     }