Bump copyright year to 2023

These problems are usually not ephemeral, and cause persistent console
spam, so they should immediately crash the server so they can be
investigated.

LICENSE.md

@@ -1,6 +1,6 @@
 MIT License
 
-Copyright (c) 2020-2022 OpenFusion Contributors
+Copyright (c) 2020-2023 OpenFusion Contributors
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal

src/core/CNProtocol.cpp

@@ -473,10 +473,15 @@ void CNServer::start() {
             } else {
                 std::lock_guard<std::mutex> lock(activeCrit); // protect operations on connections
 
+                // halt packet handling if server is shutting down
+                if (!active)
+                    return;
+
                 // player sockets
                 if (connections.find(fds[i].fd) == connections.end()) {
-                    std::cout << "[WARN] Event on non-existant socket?" << std::endl;
-                    continue; // just to be safe
+                    std::cout << "[FATAL] Event on non-existent socket: " << fds[i].fd << std::endl;
+                    assert(0);
+                    /* not reached */
                 }
 
                 CNSocket* cSock = connections[fds[i].fd];