net: move nLocalHostNonce to CConnman

This behavior seems to have been quite racy and broken.

Move nLocalHostNonce into CNode, and check received nonces against all
non-fully-connected nodes. If there's a match, assume we've connected
to ourself.

src/net.cpp

@@ -83,7 +83,6 @@ CCriticalSection cs_mapLocalHost;
 std::map<CNetAddr, LocalServiceInfo> mapLocalHost;
 static bool vfLimited[NET_MAX] = {};
 static CNode* pnodeLocalHost = NULL;
-uint64_t nLocalHostNonce = 0;
 int nMaxConnections = DEFAULT_MAX_PEER_CONNECTIONS;
 std::string strSubVersion;
 
@@ -346,6 +345,16 @@ CNode* CConnman::FindNode(const CService& addr)
     return NULL;
 }
 
+bool CConnman::CheckIncomingNonce(uint64_t nonce)
+{
+    LOCK(cs_vNodes);
+    BOOST_FOREACH(CNode* pnode, vNodes) {
+        if (!pnode->fSuccessfullyConnected && !pnode->fInbound && pnode->GetLocalNonce() == nonce)
+            return false;
+    }
+    return true;
+}
+
 CNode* CConnman::ConnectNode(CAddress addrConnect, const char *pszDest, bool fCountFailure)
 {
     if (pszDest == NULL) {
@@ -465,7 +474,6 @@ void CNode::PushVersion()
     int64_t nTime = (fInbound ? GetAdjustedTime() : GetTime());
     CAddress addrYou = (addr.IsRoutable() && !IsProxy(addr) ? addr : CAddress(CService(), addr.nServices));
     CAddress addrMe = GetLocalAddress(&addr);
-    GetRandBytes((unsigned char*)&nLocalHostNonce, sizeof(nLocalHostNonce));
     if (fLogIPs)
         LogPrint("net", "send version message: version %d, blocks=%d, us=%s, them=%s, peer=%d\n", PROTOCOL_VERSION, nBestHeight, addrMe.ToString(), addrYou.ToString(), id);
     else
@@ -2535,6 +2543,8 @@ CNode::CNode(NodeId idIn, SOCKET hSocketIn, const CAddress& addrIn, const std::s
     nextSendTimeFeeFilter = 0;
     id = idIn;
 
+    GetRandBytes((unsigned char*)&nLocalHostNonce, sizeof(nLocalHostNonce));
+
     BOOST_FOREACH(const std::string &msg, getAllNetMessageTypes())
         mapRecvBytesPerMsgCmd[msg] = 0;
     mapRecvBytesPerMsgCmd[NET_MESSAGE_COMMAND_OTHER] = 0;