From 6bd883d7ab6b263ebce2ec69a322886bc726e860 Mon Sep 17 00:00:00 2001 From: "/C=DE/ST=Berlin/L=Berlin/O=Netfilter Project/OU=Development/CN=laforge/emailAddress=laforge@netfilter.org" Date: Sat, 7 Jan 2006 22:00:51 +0000 Subject: introduce core timer handling --- src/timer.c | 167 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 167 insertions(+) create mode 100644 src/timer.c (limited to 'src/timer.c') diff --git a/src/timer.c b/src/timer.c new file mode 100644 index 0000000..47bb7c5 --- /dev/null +++ b/src/timer.c @@ -0,0 +1,167 @@ +/* ulogd, Version $LastChangedRevision: 476 $ + * + * $Id: ulogd.c 476 2004-07-23 03:19:35Z laforge $ + * + * userspace logging daemon for the netfilter subsystem + * + * (C) 2000-2005 by Harald Welte + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 + * as published by the Free Software Foundation + * + * 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; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#include +#include +#include +#include +#include + +#include +#include + +static LLIST_HEAD(ulogd_timers); + +static void tv_normalize(struct timeval *out) +{ + out->tv_sec += (out->tv_usec / 1000000); + out->tv_usec = (out->tv_usec % 1000000); +} + +/* subtract two struct timevals */ +static int tv_sub(struct timeval *res, const struct timeval *from, + const struct timeval *sub) +{ + /* FIXME: this stinks. Deal with wraps, carry, ... */ + res->tv_sec = from->tv_sec - sub->tv_sec; + res->tv_usec = from->tv_usec - sub->tv_usec; + + return 0; +} + +static int tv_add(struct timeval *res, const struct timeval *a1, + const struct timeval *a2) +{ + unsigned int carry; + + res->tv_sec = a1->tv_sec + a2->tv_sec; + res->tv_usec = a1->tv_usec + a2->tv_usec; + + tv_normalize(res); +} + +static int tv_later(const struct timeval *expires, const struct timeval *now) +{ + if (expires->tv_sec < now->tv_sec) + return 0; + else if (expires->tv_sec > now->tv_sec) + return 1; + else /* if (expires->tv_sec == now->tv_sec */ { + if (expires->tv_usec >= now->tv_usec) + return 1; + } + + return 0; +} + +static int tv_smaller(const struct timeval *t1, const struct timeval *t2) +{ + return tv_later(t2, t1); +} + +static int calc_next_expiration(void) +{ + struct ulogd_timer *cur; + struct timeval min, now, diff; + struct itimerval iti; + int ret; + +retry: + if (llist_empty(&ulogd_timers)) + return 0; + + llist_for_each_entry(cur, &ulogd_timers, list) { + if (ulogd_timers.next == &cur->list) + min = cur->expires; + + if (tv_smaller(&cur->expires, &min)) + min = cur->expires; + } + + if (tv_sub(&diff, &min, &now) < 0) { + /* FIXME: run expired timer callbacks */ + /* we cannot run timers from here since we might be + * called from register_timer() within check_n_run() */ + + /* FIXME: restart with next minimum timer */ + goto retry; + } + + /* re-set kernel timer */ + memset(&iti, 0, sizeof(iti)); + memcpy(&iti.it_value, &diff, sizeof(iti.it_value)); + ret = setitimer(ITIMER_REAL, &iti, NULL); + if (ret < 0) + return ret; + + return 0; +} + +void ulogd_timer_check_n_run(void) +{ + struct ulogd_timer *cur, *cur2; + struct timeval now; + + if (gettimeofday(&now, NULL) < 0) + return; + + llist_for_each_entry_safe(cur, cur2, &ulogd_timers, list) { + if (tv_later(&cur->expires, &now)) { + /* fist delete it from the list of timers */ + llist_del(cur); + /* then call. called function can re-add it */ + (cur->cb)(cur->data); + } + } + + calc_next_expiration(); +} + + +int ulogd_register_timer(struct ulogd_timer *timer) +{ + int ret; + struct timeval tv; + + ret = gettimeofday(&tv, NULL); + if (ret < 0) + return ret; + + /* convert expiration time into absoulte time */ + timer->expires.tv_sec += tv.tv_sec; + timer->expires.tv_usec += tv.tv_usec; + + llist_add_tail(&timer->list, &ulogd_timers); + + /* re-calculate next expiration */ + calc_next_expiration(); + + return 0; +} + +void ulogd_unregister_timer(struct ulogd_timer *timer) +{ + llist_del(&timer->list); + + /* re-calculate next expiration */ + calc_next_expiration(); +} -- cgit v1.2.3