/* *  OpenVPN -- An application to securely tunnel IP networks *             over a single UDP port, with support for TLS-based *             session authentication and key exchange, *             packet encryption, packet authentication, and *             packet compression. * *  Copyright (C) 2002 James Yonan <jim@yonan.net> * *  This program 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 2 of the License, or *  (at your option) any later version. * *  This program 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 (see the file COPYING included with this *  distribution); if not, write to the Free Software Foundation, Inc., *  59 Temple Place, Suite 330, Boston, MA  02111-1307  USA *//* * These routines are designed to optimize the calling of a routine * (normally used for tls_multi_process()) * which can be called less frequently between triggers. * * We won't optimize if we are within I_HORIZON seconds * of a trigger. * * If we are optimizing, we will call routine at least once * per I_INTERVAL seconds. *//* TLS time constants */#define TLS_MULTI_REFRESH 15    /* seconds */#define TLS_MULTI_HORIZON 60    /* seconds *//* * Interval test is true at least once per n seconds. */#define I_INTERVAL TLS_MULTI_REFRESH/* * Seconds after last trigger or before next timeout, */#define I_HORIZON  TLS_MULTI_HORIZONstruct interval{  time_t last_trigger;  time_t last_call;  bool select_timeout;};static inline boolinterval_test (struct interval* top, time_t current){  if (top->last_trigger + I_HORIZON < current &&      !(top->select_timeout || top->last_call + I_INTERVAL < current))    return false;  msg (D_TLS_DEBUG, "INTERVAL TEST SUCCEEDED");  top->select_timeout = false;  top->last_call = current;  return true;}static inline voidinterval_trigger (struct interval* top, time_t at) {  msg (D_TLS_DEBUG, "INTERVAL TRIGGER");  top->last_trigger = at;}static inline voidinterval_select_timeout (struct interval* top) {  top->select_timeout = true;}static inline voidinterval_set_timeout (struct interval* top, time_t current, time_t* timeout) {  const int to = *timeout;  if (to && to < I_HORIZON)    interval_trigger (top, current + to);  if (!to || to > I_INTERVAL)    *timeout = I_INTERVAL;}/* * Measure when n seconds past an event have elapsed */struct event_timeout{  int n;  time_t last; /* time of last event */};static inline voidevent_timeout_init (struct event_timeout* et, time_t current, int n){  et->n = n;  et->last = current;}static inline voidevent_timeout_reset (struct event_timeout* et, time_t current){  et->last = current;}static inline boolevent_timeout_trigger (struct event_timeout* et, time_t current){  if (et->n && et->last + et->n <= current)    {      msg (D_TLS_DEBUG, "ELAPSED TRIGGER (%d)", et->n);      et->last = current;      return true;    }  return false;}static inline voidevent_timeout_wakeup (struct event_timeout* et, time_t current, struct timeval* tv){  if (et->n)    {      const int wakeup = et->last + et->n - current;      if (wakeup > 0 && (!tv->tv_sec || wakeup < tv->tv_sec))	{	  msg (D_TLS_DEBUG, "ELAPSED SOONEST (%d/%d)", wakeup, et->n);	  tv->tv_sec = wakeup;	}    }}