dns_cache: Replace cache timeout mechanism with time wheel algorithm to reduce CPU usage

src/include/timer_wheel.h

@@ -0,0 +1,50 @@
+/*************************************************************************
+ *
+ * Copyright (C) 2018-2023 Ruilin Peng (Nick) <pymumu@gmail.com>.
+ *
+ * smartdns is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * smartdns is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef __TIMER_WHEEL_H
+#define __TIMER_WHEEL_H
+
+#include "list.h"
+
+struct tw_base;
+struct tw_timer_list;
+
+typedef void (*tw_func)(struct tw_timer_list *, void *, unsigned long);
+typedef void (*tw_del_func)(struct tw_timer_list *, void *);
+
+struct tw_timer_list {
+	void *data;
+	unsigned long expires;
+	tw_func function;
+	tw_del_func del_function;
+	struct list_head entry;
+};
+
+struct tw_base *tw_init_timers(void);
+
+int tw_cleanup_timers(struct tw_base *);
+
+void tw_add_timer(struct tw_base *, struct tw_timer_list *);
+
+int tw_del_timer(struct tw_base *, struct tw_timer_list *);
+
+int tw_mod_timer_pending(struct tw_base *, struct tw_timer_list *, unsigned long);
+
+int tw_mod_timer(struct tw_base *, struct tw_timer_list *, unsigned long);
+
+#endif