fix a lot of issues on psogc; add proxy module

- $ann implemented
- concurrency removed; server is now single-threaded, event-driven and much more stable
- rare seed is no longer the game id; ids are sequential from server startup so they weren't random at all before
- supports dropping privileges; now you can run it as root so it can open a sockets on low ports, then it will switch to the given user before serving any traffic
- newserv now behaves like a proxy if you run it with the --proxy-destination=<IP_OR_HOSTNAME> argument; there's also an (invisible) shell in this mode where you can inject commands to the server or client. e.g. it can always be christmas in the lobby if you do `sc DA 01 00 00`
- increased the mtu on PSODolphinConfig's tap0 configuration; this seems to make the connection more stable
- fixed some uninitialized memory bugs
- the shell is now event-driven and now uses libevent too; unfortunately this means readline doesn't work anymore (no history and vim-like shortcuts)
- made network command display consistent for input vs. output (the header appears in both cases now)
- fixed bugs in some subcommand handling (the BB logic was being applied to non-BB clients erroneously, causing most item drops not to work at all)
- fixed player tags in the short lobby data struct. unclear if this was actually a problem but it was inconsistent with other servers
- fixed "unused" field in game join command (actually it appears to be disable_udp and should be 1, not 0)
- cleaned up Server abstraction a bit
- rewrote some text functions; asan was complaining about the built-in ones for some reason
- added an optional welcome message

ServerState.cc

@@ -33,9 +33,6 @@ ServerState::ServerState() : run_dns_server(true),
 }
 
 void ServerState::add_client_to_available_lobby(shared_ptr<Client> c) {
-  rw_guard g(this->lobbies_lock, false);
-
-  // nonnegative lobby IDs are public, so start at 0
   auto it = this->id_to_lobby.lower_bound(0);
   for (; it != this->id_to_lobby.end(); it++) {
     if (!(it->second->flags & LobbyFlag::Public)) {
@@ -56,8 +53,6 @@ void ServerState::add_client_to_available_lobby(shared_ptr<Client> c) {
 }
 
 void ServerState::remove_client_from_lobby(shared_ptr<Client> c) {
-  rw_guard g(this->lobbies_lock, false);
-
   auto l = this->id_to_lobby.at(c->lobby_id);
   l->remove_client(c);
   send_player_leave_notification(l, c->lobby_client_id);
@@ -86,7 +81,6 @@ void ServerState::change_client_lobby(shared_ptr<Client> c, shared_ptr<Lobby> ne
 
 void ServerState::send_lobby_join_notifications(shared_ptr<Lobby> l,
     shared_ptr<Client> joining_client) {
-  rw_guard g2(l->lock, false);
   for (auto& other_client : l->clients) {
     if (!other_client) {
       continue;
@@ -99,12 +93,10 @@ void ServerState::send_lobby_join_notifications(shared_ptr<Lobby> l,
 }
 
 shared_ptr<Lobby> ServerState::find_lobby(uint32_t lobby_id) {
-  rw_guard g(this->lobbies_lock, false);
   return this->id_to_lobby.at(lobby_id);
 }
 
 vector<shared_ptr<Lobby>> ServerState::all_lobbies() {
-  rw_guard g(this->lobbies_lock, false);
   vector<shared_ptr<Lobby>> ret;
   for (auto& it : this->id_to_lobby) {
     ret.emplace_back(it.second);
@@ -114,23 +106,14 @@ vector<shared_ptr<Lobby>> ServerState::all_lobbies() {
 
 void ServerState::add_lobby(shared_ptr<Lobby> l) {
   l->lobby_id = this->next_lobby_id++;
-
-  rw_guard g(this->lobbies_lock, true);
   if (this->id_to_lobby.count(l->lobby_id)) {
     throw logic_error("lobby already exists with the given id");
   }
-
-  log(INFO, "creating lobby %" PRId64, l->lobby_id);
   this->id_to_lobby.emplace(l->lobby_id, l);
 }
 
 void ServerState::remove_lobby(uint32_t lobby_id) {
-  rw_guard g(this->lobbies_lock, true);
-  auto it = this->id_to_lobby.find(lobby_id);
-  if (it == this->id_to_lobby.end()) {
-    return;
-  }
-  this->id_to_lobby.erase(it);
+  this->id_to_lobby.erase(lobby_id);
 }
 
 shared_ptr<Client> ServerState::find_client(const char16_t* identifier,