Add session timer

src/session/session_timer.h

@@ -0,0 +1,26 @@
+#ifndef _SESSION_TIMER_H
+#define _SESSION_TIMER_H
+
+#ifdef __cpluscplus
+extern "C"
+{
+#endif
+
+#include "session.h"
+
+struct session_timer;
+struct session_timer *session_timer_create();
+void session_timer_destroy(struct session_timer *timer);
+void session_timer_add_session(struct session_timer *timer, struct session *sess);
+void session_timer_del_session(struct session_timer *timer, struct session *sess);
+/*
+ * return one session which timeout, or NULL if no session timeout.
+ * if return session, the session will be removed from timer.
+ */
+struct session *session_timer_expire_session(struct session_timer *timer, uint64_t abs_current_ts);
+
+#ifdef __cpluscplus
+}
+#endif
+
+#endif