SSU2: handle standard network errors more correctly

Signed-off-by: R4SAS <r4sas@i2pmail.org>

libi2pd/SSU2.cpp

@@ -236,7 +236,19 @@ namespace transport
 	void SSU2Server::HandleReceivedFrom (const boost::system::error_code& ecode, size_t bytes_transferred,
 		Packet * packet, boost::asio::ip::udp::socket& socket)
 	{
-		if (!ecode)
+		if (!ecode
+			|| ecode == boost::asio::error::connection_refused
+			|| ecode == boost::asio::error::connection_reset
+			|| ecode == boost::asio::error::network_unreachable
+			|| ecode == boost::asio::error::host_unreachable
+#ifdef _WIN32 // windows can throw WinAPI error, which is not handled by ASIO
+			|| ecode.value() == boost::winapi::ERROR_CONNECTION_REFUSED_
+			|| ecode.value() == boost::winapi::ERROR_NETWORK_UNREACHABLE_
+			|| ecode.value() == boost::winapi::ERROR_HOST_UNREACHABLE_
+#endif
+		)
+		// just try continue reading when received ICMP response otherwise socket can crash,
+		// but better to find out which host were sent it and mark that router as unreachable
 		{
 			i2p::transport::transports.UpdateReceivedBytes (bytes_transferred);
 			packet->len = bytes_transferred;