net: Disable P2P alert system

src/main.cpp

@@ -4278,32 +4278,8 @@ bool static ProcessMessage(CNode* pfrom, string strCommand, CDataStream& vRecv,
 
     else if (fAlerts && strCommand == "alert")
     {
-        CAlert alert;
-        vRecv >> alert;
-
-        uint256 alertHash = alert.GetHash();
-        if (pfrom->setKnown.count(alertHash) == 0)
-        {
-            if (alert.ProcessAlert())
-            {
-                // Relay
-                pfrom->setKnown.insert(alertHash);
-                {
-                    LOCK(cs_vNodes);
-                    BOOST_FOREACH(CNode* pnode, vNodes)
-                        alert.RelayTo(pnode);
-                }
-            }
-            else {
-                // Small DoS penalty so peers that send us lots of
-                // duplicate/expired/invalid-signature/whatever alerts
-                // eventually get banned.
-                // This isn't a Misbehaving(100) (immediate ban) because the
-                // peer might be an older or different implementation with
-                // a different signature key, etc.
-                Misbehaving(pfrom->GetId(), 10);
-            }
-        }
+        // Alert message handling disabled
+        // See https://bitcoin.org/en/alert/2016-11-01-alert-retirement
     }