pinger.c

   1 /*
   2  * pinger.c: centralised module that deals with sending TS_PING
   3  * keepalives, to avoid replicating this code in multiple backends.
   4  */
   5
   6 #include "putty.h"
   7
   8 struct pinger_tag {
   9     int interval;
  10     int pending;
  11     long next;
  12     Backend *back;
  13     void *backhandle;
  14 };
  15
  16 static void pinger_schedule(Pinger pinger);
  17
  18 static void pinger_timer(void *ctx, long now)
  19 {
  20     Pinger pinger = (Pinger)ctx;
  21
  22     if (pinger->pending && now - pinger->next >= 0) {
  23         pinger->back->special(pinger->backhandle, TS_PING);
  24         pinger->pending = FALSE;
  25         pinger_schedule(pinger);
  26     }
  27 }
  28
  29 static void pinger_schedule(Pinger pinger)
  30 {
  31     int next;
  32
  33     if (!pinger->interval) {
  34         pinger->pending = FALSE;       /* cancel any pending ping */
  35         return;
  36     }
  37
  38     next = schedule_timer(pinger->interval * TICKSPERSEC,
  39                           pinger_timer, pinger);
  40     if (!pinger->pending || next < pinger->next) {
  41         pinger->next = next;
  42         pinger->pending = TRUE;
  43     }
  44 }
  45
  46 Pinger pinger_new(Config *cfg, Backend *back, void *backhandle)
  47 {
  48     Pinger pinger = snew(struct pinger_tag);
  49
  50     pinger->interval = cfg->ping_interval;
  51     pinger->pending = FALSE;
  52     pinger->back = back;
  53     pinger->backhandle = backhandle;
  54     pinger_schedule(pinger);
  55
  56     return pinger;
  57 }
  58
  59 void pinger_reconfig(Pinger pinger, Config *oldcfg, Config *newcfg)
  60 {
  61     if (oldcfg->ping_interval != newcfg->ping_interval) {
  62         pinger->interval = newcfg->ping_interval;
  63         pinger_schedule(pinger);
  64     }
  65 }
  66
  67 void pinger_free(Pinger pinger)
  68 {
  69     expire_timer_context(pinger);
  70     sfree(pinger);
  71 }