Merge pull request #1747 from subtly/connectlimit

simple max inc connect limit

libp2p/Host.cpp

@@ -226,6 +226,12 @@ void Host::startPeerSession(Public const& _id, RLP const& _rlp, RLPXFrameIO* _io
 					return;
 				}
 		
+		if (peerCount() > 2 * m_idealPeerCount)
+		{
+			ps->disconnect(TooManyPeers);
+			return;
+		}
+		
 		// todo: mutex Session::m_capabilities and move for(:caps) out of mutex.
 		unsigned o = (unsigned)UserPacket;
 		for (auto const& i: caps)
@@ -335,6 +341,15 @@ void Host::runAcceptor()
 		auto socket = make_shared<RLPXSocket>(new bi::tcp::socket(m_ioService));
 		m_tcp4Acceptor.async_accept(socket->ref(), [=](boost::system::error_code ec)
 		{
+			if (peerCount() > 2 * m_idealPeerCount)
+			{
+				clog(NetConnect) << "Dropping incoming connect due to maximum peer count (2 * ideal peer count): " << socket->remoteEndpoint();
+				socket->close();
+				if (ec.value() < 1)
+					runAcceptor();
+				return;
+			}
+			
 			// if no error code
 			bool success = false;
 			if (!ec)