release/src/router/openvpn/otime.h

   1 /*
   2  *  OpenVPN -- An application to securely tunnel IP networks
   3  *             over a single TCP/UDP port, with support for SSL/TLS-based
   4  *             session authentication and key exchange,
   5  *             packet encryption, packet authentication, and
   6  *             packet compression.
   7  *
   8  *  Copyright (C) 2002-2010 OpenVPN Technologies, Inc. <sales@openvpn.net>
   9  *
  10  *  This program is free software; you can redistribute it and/or modify
  11  *  it under the terms of the GNU General Public License version 2
  12  *  as published by the Free Software Foundation.
  13  *
  14  *  This program is distributed in the hope that it will be useful,
  15  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17  *  GNU General Public License for more details.
  18  *
  19  *  You should have received a copy of the GNU General Public License
  20  *  along with this program (see the file COPYING included with this
  21  *  distribution); if not, write to the Free Software Foundation, Inc.,
  22  *  59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  23  */
  24
  25 #ifndef OTIME_H
  26 #define OTIME_H
  27
  28 #include "common.h"
  29 #include "integer.h"
  30 #include "buffer.h"
  31
  32 struct frequency_limit
  33 {
  34   int max;
  35   int per;
  36   int n;
  37   time_t reset;
  38 };
  39
  40 struct frequency_limit *frequency_limit_init (int max, int per);
  41 void frequency_limit_free (struct frequency_limit *f);
  42 bool frequency_limit_event_allowed (struct frequency_limit *f);
  43
  44 #ifdef WIN32
  45 int gettimeofday(struct timeval *tv, void *tz);
  46 #endif
  47
  48 /* format a time_t as ascii, or use current time if 0 */
  49 const char* time_string (time_t t, int usec, bool show_usec, struct gc_arena *gc);
  50
  51 /* struct timeval functions */
  52
  53 const char *tv_string (const struct timeval *tv, struct gc_arena *gc);
  54 const char *tv_string_abs (const struct timeval *tv, struct gc_arena *gc);
  55
  56 extern time_t now; /* updated frequently to time(NULL) */
  57
  58 void time_test (void);
  59
  60 #if TIME_BACKTRACK_PROTECTION && defined(HAVE_GETTIMEOFDAY)
  61
  62 void update_now (const time_t system_time);
  63
  64 extern time_t now_usec;
  65 void update_now_usec (struct timeval *tv);
  66
  67 static inline int
  68 openvpn_gettimeofday (struct timeval *tv, void *tz)
  69 {
  70   const int status = gettimeofday (tv, tz);
  71   if (!status)
  72     {
  73       update_now_usec (tv);
  74       tv->tv_sec = now;
  75       tv->tv_usec = now_usec;
  76     }
  77   return status;
  78 }
  79
  80 static inline void
  81 update_time (void)
  82 {
  83 #ifdef WIN32
  84   /* on WIN32, gettimeofday is faster than time(NULL) */
  85   struct timeval tv;
  86   openvpn_gettimeofday (&tv, NULL);
  87 #else
  88   update_now (time (NULL));
  89 #endif
  90 }
  91
  92 #else /* !(TIME_BACKTRACK_PROTECTION && defined(HAVE_GETTIMEOFDAY)) */
  93
  94 static inline void
  95 update_time (void)
  96 {
  97 #if defined(WIN32) && defined(HAVE_GETTIMEOFDAY)
  98   struct timeval tv;
  99   if (!gettimeofday (&tv, NULL))
 100     {
 101       if (tv.tv_sec != now)
 102         now = tv.tv_sec;
 103     }
 104 #else
 105   const time_t real_time = time (NULL);
 106   if (real_time != now)
 107     now = real_time;
 108 #endif
 109 }
 110
 111 #ifdef HAVE_GETTIMEOFDAY
 112
 113 static inline int
 114 openvpn_gettimeofday (struct timeval *tv, void *tz)
 115 {
 116   return gettimeofday (tv, tz);
 117 }
 118
 119 #endif
 120
 121 #endif /* TIME_BACKTRACK_PROTECTION && defined(HAVE_GETTIMEOFDAY) */
 122
 123 static inline time_t
 124 openvpn_time (time_t *t)
 125 {
 126   update_time ();
 127   if (t)
 128     *t = now;
 129   return now;
 130 }
 131
 132 static inline void
 133 tv_clear (struct timeval *tv)
 134 {
 135   tv->tv_sec = 0;
 136   tv->tv_usec = 0;
 137 }
 138
 139 static inline bool
 140 tv_defined (const struct timeval *tv)
 141 {
 142   return tv->tv_sec > 0 && tv->tv_usec > 0;
 143 }
 144
 145 /* return tv1 - tv2 in usec, constrained by max_seconds */
 146 static inline int
 147 tv_subtract (const struct timeval *tv1, const struct timeval *tv2, const unsigned int max_seconds)
 148 {
 149   const int max_usec = max_seconds * 1000000;
 150   const int sec_diff = tv1->tv_sec - tv2->tv_sec;
 151
 152   if (sec_diff > ((int)max_seconds + 10))
 153     return max_usec;
 154   else if (sec_diff < -((int)max_seconds + 10))
 155     return -max_usec;
 156   return constrain_int (sec_diff * 1000000 + (tv1->tv_usec - tv2->tv_usec), -max_usec, max_usec);
 157 }
 158
 159 static inline void
 160 tv_add (struct timeval *dest, const struct timeval *src)
 161 {
 162   dest->tv_sec += src->tv_sec;
 163   dest->tv_usec += src->tv_usec;
 164   dest->tv_sec += (dest->tv_usec >> 20);
 165   dest->tv_usec &= 0x000FFFFF;
 166   if (dest->tv_usec >= 1000000)
 167     {
 168       dest->tv_usec -= 1000000;
 169       dest->tv_sec += 1;
 170     }
 171 }
 172
 173 static inline bool
 174 tv_lt (const struct timeval *t1, const struct timeval *t2)
 175 {
 176   if (t1->tv_sec < t2->tv_sec)
 177     return true;
 178   else if (t1->tv_sec > t2->tv_sec)
 179     return false;
 180   else
 181     return t1->tv_usec < t2->tv_usec;
 182 }
 183
 184 static inline bool
 185 tv_le (const struct timeval *t1, const struct timeval *t2)
 186 {
 187   if (t1->tv_sec < t2->tv_sec)
 188     return true;
 189   else if (t1->tv_sec > t2->tv_sec)
 190     return false;
 191   else
 192     return t1->tv_usec <= t2->tv_usec;
 193 }
 194
 195 static inline bool
 196 tv_ge (const struct timeval *t1, const struct timeval *t2)
 197 {
 198   if (t1->tv_sec > t2->tv_sec)
 199     return true;
 200   else if (t1->tv_sec < t2->tv_sec)
 201     return false;
 202   else
 203     return t1->tv_usec >= t2->tv_usec;
 204 }
 205
 206 static inline bool
 207 tv_gt (const struct timeval *t1, const struct timeval *t2)
 208 {
 209   if (t1->tv_sec > t2->tv_sec)
 210     return true;
 211   else if (t1->tv_sec < t2->tv_sec)
 212     return false;
 213   else
 214     return t1->tv_usec > t2->tv_usec;
 215 }
 216
 217 static inline bool
 218 tv_eq (const struct timeval *t1, const struct timeval *t2)
 219 {
 220   return t1->tv_sec == t2->tv_sec && t1->tv_usec == t2->tv_usec;
 221 }
 222
 223 static inline void
 224 tv_delta (struct timeval *dest, const struct timeval *t1, const struct timeval *t2)
 225 {
 226   int sec = t2->tv_sec - t1->tv_sec;
 227   int usec = t2->tv_usec - t1->tv_usec;
 228
 229   while (usec < 0)
 230     {
 231       usec += 1000000;
 232       sec -= 1;
 233     }
 234
 235   if (sec < 0)
 236     usec = sec = 0;
 237
 238   dest->tv_sec = sec;
 239   dest->tv_usec = usec;
 240 }
 241
 242 #define TV_WITHIN_SIGMA_MAX_SEC 600
 243 #define TV_WITHIN_SIGMA_MAX_USEC (TV_WITHIN_SIGMA_MAX_SEC * 1000000)
 244
 245 /*
 246  * Is t1 and t2 within sigma microseconds of each other?
 247  */
 248 static inline bool
 249 tv_within_sigma (const struct timeval *t1, const struct timeval *t2, unsigned int sigma)
 250 {
 251   const int delta = tv_subtract (t1, t2, TV_WITHIN_SIGMA_MAX_SEC); /* sigma should be less than 10 minutes */
 252   return -(int)sigma <= delta && delta <= (int)sigma;
 253 }
 254
 255 /*
 256  * Used to determine in how many seconds we should be
 257  * called again.
 258  */
 259 static inline void
 260 interval_earliest_wakeup (interval_t *wakeup, time_t at, time_t current) {
 261   if (at > current)
 262     {
 263       const interval_t delta = (interval_t) (at - current);
 264       if (delta < *wakeup)
 265         *wakeup = delta;
 266       if (*wakeup < 0)
 267         *wakeup = 0;
 268     }
 269 }
 270
 271 #endif