Merge pull request #1694 from sipa/fix_netloops

Fix infinite loops in connection logic

src/init.cpp

@@ -357,7 +357,7 @@ bool AppInit2()
         SoftSetBoolArg("-listen", true);
     }
 
-    if (mapArgs.count("-connect")) {
+    if (mapArgs.count("-connect") && mapMultiArgs["-connect"].size() > 0) {
         // when only connecting to trusted nodes, do not seed via DNS, or listen by default
         SoftSetBoolArg("-dnsseed", false);
         SoftSetBoolArg("-listen", false);

src/net.cpp

@@ -1391,7 +1391,7 @@ void ThreadOpenConnections2(void* parg)
     printf("ThreadOpenConnections started\n");
 
     // Connect to specific addresses
-    if (mapArgs.count("-connect"))
+    if (mapArgs.count("-connect") && mapMultiArgs["-connect"].size() > 0)
     {
         for (int64 nLoop = 0;; nLoop++)
         {
@@ -1407,6 +1407,7 @@ void ThreadOpenConnections2(void* parg)
                         return;
                 }
             }
+            Sleep(500);
         }
     }
 
@@ -1480,7 +1481,12 @@ void ThreadOpenConnections2(void* parg)
             if (!addr.IsValid() || setConnected.count(addr.GetGroup()) || IsLocal(addr))
                 break;
 
+            // If we didn't find an appropriate destination after trying 100 addresses fetched from addrman,
+            // stop this loop, and let the outer loop run again (which sleeps, adds seed nodes, recalculates
+            // already-connected network ranges, ...) before trying new addrman addresses.
             nTries++;
+            if (nTries > 100)
+                break;
 
             if (IsLimited(addr))
                 continue;