src/TortoisePlink/PINGER.C

   1 /*\r
   2  * pinger.c: centralised module that deals with sending TS_PING\r
   3  * keepalives, to avoid replicating this code in multiple backends.\r
   4  */\r
   5 \r
   6 #include "putty.h"\r
   7 \r
   8 struct pinger_tag {\r
   9     int interval;\r
  10     int pending;\r
  11     unsigned long when_set, next;\r
  12     Backend *back;\r
  13     void *backhandle;\r
  14 };\r
  15 \r
  16 static void pinger_schedule(Pinger pinger);\r
  17 \r
  18 static void pinger_timer(void *ctx, unsigned long now)\r
  19 {\r
  20     Pinger pinger = (Pinger)ctx;\r
  21 \r
  22     if (pinger->pending && now == pinger->next) {\r
  23         pinger->back->special(pinger->backhandle, TS_PING);\r
  24         pinger->pending = FALSE;\r
  25         pinger_schedule(pinger);\r
  26     }\r
  27 }\r
  28 \r
  29 static void pinger_schedule(Pinger pinger)\r
  30 {\r
  31     unsigned long next;\r
  32 \r
  33     if (!pinger->interval) {\r
  34         pinger->pending = FALSE;       /* cancel any pending ping */\r
  35         return;\r
  36     }\r
  37 \r
  38     next = schedule_timer(pinger->interval * TICKSPERSEC,\r
  39                           pinger_timer, pinger);\r
  40     if (!pinger->pending ||\r
  41         (next - pinger->when_set) < (pinger->next - pinger->when_set)) {\r
  42         pinger->next = next;\r
  43         pinger->when_set = timing_last_clock();\r
  44         pinger->pending = TRUE;\r
  45     }\r
  46 }\r
  47 \r
  48 Pinger pinger_new(Conf *conf, Backend *back, void *backhandle)\r
  49 {\r
  50     Pinger pinger = snew(struct pinger_tag);\r
  51 \r
  52     pinger->interval = conf_get_int(conf, CONF_ping_interval);\r
  53     pinger->pending = FALSE;\r
  54     pinger->back = back;\r
  55     pinger->backhandle = backhandle;\r
  56     pinger_schedule(pinger);\r
  57 \r
  58     return pinger;\r
  59 }\r
  60 \r
  61 void pinger_reconfig(Pinger pinger, Conf *oldconf, Conf *newconf)\r
  62 {\r
  63     int newinterval = conf_get_int(newconf, CONF_ping_interval);\r
  64     if (conf_get_int(oldconf, CONF_ping_interval) != newinterval) {\r
  65         pinger->interval = newinterval;\r
  66         pinger_schedule(pinger);\r
  67     }\r
  68 }\r
  69 \r
  70 void pinger_free(Pinger pinger)\r
  71 {\r
  72     expire_timer_context(pinger);\r
  73     sfree(pinger);\r
  74 }\r