putty/pinger.c

73 строки
1.6 KiB
C

/*
* pinger.c: centralised module that deals with sending SS_PING
* keepalives, to avoid replicating this code in multiple backends.
*/
#include "putty.h"
struct Pinger {
int interval;
int pending;
unsigned long when_set, next;
Backend *backend;
};
static void pinger_schedule(Pinger *pinger);
static void pinger_timer(void *ctx, unsigned long now)
{
Pinger *pinger = (Pinger *)ctx;
if (pinger->pending && now == pinger->next) {
backend_special(pinger->backend, SS_PING, 0);
pinger->pending = false;
pinger_schedule(pinger);
}
}
static void pinger_schedule(Pinger *pinger)
{
unsigned long next;
if (!pinger->interval) {
pinger->pending = false; /* cancel any pending ping */
return;
}
next = schedule_timer(pinger->interval * TICKSPERSEC,
pinger_timer, pinger);
if (!pinger->pending ||
(next - pinger->when_set) < (pinger->next - pinger->when_set)) {
pinger->next = next;
pinger->when_set = timing_last_clock();
pinger->pending = true;
}
}
Pinger *pinger_new(Conf *conf, Backend *backend)
{
Pinger *pinger = snew(Pinger);
pinger->interval = conf_get_int(conf, CONF_ping_interval);
pinger->pending = false;
pinger->backend = backend;
pinger_schedule(pinger);
return pinger;
}
void pinger_reconfig(Pinger *pinger, Conf *oldconf, Conf *newconf)
{
int newinterval = conf_get_int(newconf, CONF_ping_interval);
if (conf_get_int(oldconf, CONF_ping_interval) != newinterval) {
pinger->interval = newinterval;
pinger_schedule(pinger);
}
}
void pinger_free(Pinger *pinger)
{
expire_timer_context(pinger);
sfree(pinger);
}