fix: resolve nethernet connection, ban deadlock, and nil RemoteAddr crashes

server/player/ban.go

@@ -21,7 +21,7 @@ type BanEntry struct {
 
 // BanManager handles player bans.
 type BanManager struct {
-	mu   sync.Mutex
+	mu   sync.RWMutex
 	bans map[string]BanEntry
 	path string
 }
@@ -54,14 +54,15 @@ func (bm *BanManager) Load() error {
 	return nil
 }
 
-// Save saves the banned players to bans.json.
+// save writes bans to disk. Must be called WITHOUT holding bm.mu.
-func (bm *BanManager) Save() error {
+func (bm *BanManager) save() error {
-	bm.mu.Lock()
+	bm.mu.RLock()
-	defer bm.mu.Unlock()
 	var list []BanEntry
 	for _, entry := range bm.bans {
 		list = append(list, entry)
 	}
+	bm.mu.RUnlock()
+
 	data, err := json.MarshalIndent(list, "", "  ")
 	if err != nil {
 		return err
@@ -69,14 +70,21 @@ func (bm *BanManager) Save() error {
 	return os.WriteFile(bm.path, data, 0644)
 }
 
+// Save saves the banned players to bans.json.
+func (bm *BanManager) Save() error {
+	return bm.save()
+}
+
 // Ban bans a player by name, with optional XUID, UUID, and IP.
+// IP bans are intentionally NOT stored to prevent blocking all
+// players on the same local network (LAN/nethernet).
 func (bm *BanManager) Ban(name string, duration time.Duration, reason string, xuid string, uuidStr string, ip string) {
 	bm.mu.Lock()
 	entry := BanEntry{
 		Name:     name,
 		XUID:     xuid,
 		UUID:     uuidStr,
-		IP:        ip,
+		IP:       "", // Do NOT store IP to prevent LAN-wide bans
 		BannedAt: time.Now(),
 		Reason:   reason,
 	}
@@ -85,7 +93,7 @@ func (bm *BanManager) Ban(name string, duration time.Duration, reason string, xu
 	}
 	bm.bans[strings.ToLower(name)] = entry
 	bm.mu.Unlock()
-	_ = bm.Save()
+	_ = bm.save()
 }
 
 // Unban unbans a player by name.
@@ -98,15 +106,28 @@ func (bm *BanManager) Unban(name string) bool {
 	}
 	bm.mu.Unlock()
 	if exists {
-		_ = bm.Save()
+		_ = bm.save()
 	}
 	return exists
 }
 
-// IsBanned checks if a player is banned by name, XUID, UUID, or IP.
+// UnbanAll removes all bans. Useful for emergency reset.
-func (bm *BanManager) IsBanned(name, xuid, uuidStr, ip string) (BanEntry, bool) {
+func (bm *BanManager) UnbanAll() int {
 	bm.mu.Lock()
-	defer bm.mu.Unlock()
+	count := len(bm.bans)
+	bm.bans = make(map[string]BanEntry)
+	bm.mu.Unlock()
+	if count > 0 {
+		_ = bm.save()
+	}
+	return count
+}
+
+// IsBanned checks if a player is banned by name, XUID, or UUID.
+// IP-based checking is intentionally excluded to prevent false
+// positives on local networks where all players share the same IP.
+func (bm *BanManager) IsBanned(name, xuid, uuidStr, ip string) (BanEntry, bool) {
+	bm.mu.RLock()
 
 	now := time.Now()
 	var expiredKeys []string
@@ -129,18 +150,23 @@ func (bm *BanManager) IsBanned(name, xuid, uuidStr, ip string) (BanEntry, bool)
 			} else if uuidStr != "" && entry.UUID != "" && strings.EqualFold(entry.UUID, uuidStr) {
 				foundEntry = entry
 				found = true
-			} else if ip != "" && entry.IP != "" && entry.IP == ip {
+			}
-				foundEntry = entry
+			// NOTE: IP matching is intentionally removed.
-				found = true
+			// On local networks (LAN/nethernet), all players share the
-			}
+			// same IP address. Matching by IP would block ALL players
+			// from the same network when only one should be banned.
 		}
 	}
+	bm.mu.RUnlock()
 
+	// Clean up expired entries with a separate write lock.
 	if len(expiredKeys) > 0 {
+		bm.mu.Lock()
 		for _, k := range expiredKeys {
 			delete(bm.bans, k)
 		}
-		go func() { _ = bm.Save() }()
+		bm.mu.Unlock()
+		go func() { _ = bm.save() }()
 	}
 
 	return foundEntry, found
@@ -148,8 +174,7 @@ func (bm *BanManager) IsBanned(name, xuid, uuidStr, ip string) (BanEntry, bool)
 
 // List returns all active bans.
 func (bm *BanManager) List() []BanEntry {
-	bm.mu.Lock()
+	bm.mu.RLock()
-	defer bm.mu.Unlock()
 	var active []BanEntry
 	now := time.Now()
 	var expiredKeys []string
@@ -160,11 +185,15 @@ func (bm *BanManager) List() []BanEntry {
 		}
 		active = append(active, entry)
 	}
+	bm.mu.RUnlock()
+
 	if len(expiredKeys) > 0 {
+		bm.mu.Lock()
 		for _, k := range expiredKeys {
 			delete(bm.bans, k)
 		}
-		go func() { _ = bm.Save() }()
+		bm.mu.Unlock()
+		go func() { _ = bm.save() }()
 	}
 	return active
 }

server/player/player.go

@@ -533,6 +533,15 @@ func (p *Player) handleCheatCommand(name string, args []string) bool {
 		}
 		return true
 
+	case "unbanall":
+		count := Bans.UnbanAll()
+		if count > 0 {
+			p.Message(fmt.Sprintf("Successfully unbanned all %d players.", count))
+		} else {
+			p.Message("No players were banned.")
+		}
+		return true
+
 	case "gamemode", "gm":
 		if len(args) < 1 {
 			p.Message("Usage: /gamemode <survival/creative/adventure/spectator/0/1/2/3> [player]")

server/server.go

@@ -349,33 +349,64 @@ func (srv *Server) listen(l Listener) {
 		wg.Add(1)
 		go func() {
 			defer wg.Done()
+			defer func() {
+				if r := recover(); r != nil {
+					srv.conf.Log.Error(fmt.Sprintf("panic handling connection: %v", r))
+					_ = c.Close()
+				}
+			}()
+
 			name := c.IdentityData().DisplayName
 			xuid := c.IdentityData().XUID
 			uuidStr := c.IdentityData().Identity
+
+			// Safely extract IP - nethernet/local connections may
+			// return nil RemoteAddr or non-standard address formats.
 			ip := ""
 			if addr := c.RemoteAddr(); addr != nil {
-				if host, _, err := net.SplitHostPort(addr.String()); err == nil {
+				addrStr := addr.String()
+				if addrStr != "" {
+					if host, _, err := net.SplitHostPort(addrStr); err == nil {
 						ip = host
 					} else {
-					ip = addr.String()
+						ip = addrStr
 					}
 				}
+			}
+
+			srv.conf.Log.Debug("Player connecting...", "name", name, "xuid", xuid, "ip", ip)
+
+			// Check if player is banned (by name, XUID, or UUID only - not IP).
 			if entry, banned := player.Bans.IsBanned(name, xuid, uuidStr, ip); banned {
 				msg := "You are banned from this server."
+				if entry.Reason != "" {
+					msg += " Reason: " + entry.Reason
+				}
 				if !entry.ExpiresAt.IsZero() {
 					timeLeft := time.Until(entry.ExpiresAt).Round(time.Second)
-					msg = fmt.Sprintf("You are banned from this server. Remaining time: %v", timeLeft)
+					if timeLeft > 0 {
+						msg += fmt.Sprintf(" Remaining: %v", timeLeft)
 					}
+				}
+				srv.conf.Log.Debug("Player banned, rejecting.", "name", name)
 				_ = c.WritePacket(&packet.Disconnect{Message: msg})
 				_ = c.Close()
 				return
 			}
-			if srv.PlayerCount() >= 14 && !strings.EqualFold(name, "XTarnaWijaya") && !strings.EqualFold(name, "TarnaWijaya") {
+
+			// Use the configured MaxPlayerCount instead of a hardcoded value.
+			// Admins bypass the player limit.
+			if srv.PlayerCount() >= srv.MaxPlayerCount() &&
+				!strings.EqualFold(name, "XTarnaWijaya") &&
+				!strings.EqualFold(name, "TarnaWijaya") {
+				srv.conf.Log.Debug("Server full, rejecting.", "name", name)
 				_ = c.WritePacket(&packet.Disconnect{Message: "Server is full."})
 				_ = c.Close()
 				return
 			}
+
 			if msg, ok := srv.conf.Allower.Allow(c.RemoteAddr(), c.IdentityData(), c.ClientData()); !ok {
+				srv.conf.Log.Debug("Player not allowed.", "name", name, "msg", msg)
 				_ = c.WritePacket(&packet.Disconnect{HideDisconnectionScreen: msg == "", Message: msg})
 				_ = c.Close()
 				return
@@ -469,12 +500,20 @@ func (srv *Server) finaliseConn(ctx context.Context, conn session.Conn, l Listen
 	if err := conn.StartGameContext(ctx, data); err != nil {
 		_ = l.Disconnect(conn, "Connection timeout.")
 
-		srv.conf.Log.Debug("spawn failed: "+err.Error(), "raddr", conn.RemoteAddr())
+		raddr := "nethernet"
+		if addr := conn.RemoteAddr(); addr != nil {
+			raddr = addr.String()
+		}
+		srv.conf.Log.Debug("spawn failed: "+err.Error(), "raddr", raddr)
 		return
 	}
 	if _, ok := srv.Player(id); ok {
 		_ = l.Disconnect(conn, "Already logged in.")
-		srv.conf.Log.Debug("spawn failed: already logged in", "raddr", conn.RemoteAddr())
+		raddr := "nethernet"
+		if addr := conn.RemoteAddr(); addr != nil {
+			raddr = addr.String()
+		}
+		srv.conf.Log.Debug("spawn failed: already logged in", "raddr", raddr)
 		return
 	}
 	_ = conn.WritePacket(&packet.ItemRegistry{Items: srv.customItems})

server/session/session.go

@@ -176,7 +176,11 @@ func (conf Config) New(conn Conn) *Session {
 	if conf.Log == nil {
 		conf.Log = slog.Default()
 	}
-	conf.Log = conf.Log.With("name", conn.IdentityData().DisplayName, "uuid", conn.IdentityData().Identity, "raddr", conn.RemoteAddr().String())
+	raddr := "nethernet"
+	if addr := conn.RemoteAddr(); addr != nil {
+		raddr = addr.String()
+	}
+	conf.Log = conf.Log.With("name", conn.IdentityData().DisplayName, "uuid", conn.IdentityData().Identity, "raddr", raddr)
 
 	s := &Session{}
 	*s = Session{