summaryrefslogtreecommitdiffstats
path: root/openbsc/src/timer.c
diff options
context:
space:
mode:
Diffstat (limited to 'openbsc/src/timer.c')
-rw-r--r--openbsc/src/timer.c174
1 files changed, 174 insertions, 0 deletions
diff --git a/openbsc/src/timer.c b/openbsc/src/timer.c
new file mode 100644
index 000000000..a942ffd6d
--- /dev/null
+++ b/openbsc/src/timer.c
@@ -0,0 +1,174 @@
+/*
+ * (C) 2008,2009 by Holger Hans Peter Freyther <zecke@selfish.org>
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * 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.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ */
+
+#include <assert.h>
+#include <string.h>
+#include <openbsc/timer.h>
+
+static LLIST_HEAD(timer_list);
+static struct timeval s_nearest_time;
+static struct timeval s_select_time;
+
+#define MICRO_SECONDS 1000000LL
+
+#define TIME_SMALLER(left, right) \
+ (left.tv_sec*MICRO_SECONDS+left.tv_usec) <= (right.tv_sec*MICRO_SECONDS+right.tv_usec)
+
+void bsc_add_timer(struct timer_list *timer)
+{
+ struct timer_list *list_timer;
+
+ /* TODO: Optimize and remember the closest item... */
+ timer->active = 1;
+
+ /* this might be called from within update_timers */
+ llist_for_each_entry(list_timer, &timer_list, entry)
+ if (timer == list_timer)
+ return;
+
+ timer->in_list = 1;
+ llist_add(&timer->entry, &timer_list);
+}
+
+void bsc_schedule_timer(struct timer_list *timer, int seconds, int microseconds)
+{
+ struct timeval current_time;
+
+ gettimeofday(&current_time, NULL);
+ unsigned long long currentTime = current_time.tv_sec * MICRO_SECONDS + current_time.tv_usec;
+ currentTime += seconds * MICRO_SECONDS + microseconds;
+ timer->timeout.tv_sec = currentTime / MICRO_SECONDS;
+ timer->timeout.tv_usec = currentTime % MICRO_SECONDS;
+ bsc_add_timer(timer);
+}
+
+void bsc_del_timer(struct timer_list *timer)
+{
+ if (timer->in_list) {
+ timer->active = 0;
+ timer->in_list = 0;
+ llist_del(&timer->entry);
+ }
+}
+
+int bsc_timer_pending(struct timer_list *timer)
+{
+ return timer->active;
+}
+
+/*
+ * if we have a nearest time return the delta between the current
+ * time and the time of the nearest timer.
+ * If the nearest timer timed out return NULL and then we will
+ * dispatch everything after the select
+ */
+struct timeval *bsc_nearest_timer()
+{
+ struct timeval current_time;
+
+ if (s_nearest_time.tv_sec == 0 && s_nearest_time.tv_usec == 0)
+ return NULL;
+
+ if (gettimeofday(&current_time, NULL) == -1)
+ return NULL;
+
+ unsigned long long nearestTime = s_nearest_time.tv_sec * MICRO_SECONDS + s_nearest_time.tv_usec;
+ unsigned long long currentTime = current_time.tv_sec * MICRO_SECONDS + current_time.tv_usec;
+
+ if (nearestTime < currentTime) {
+ s_select_time.tv_sec = 0;
+ s_select_time.tv_usec = 0;
+ } else {
+ s_select_time.tv_sec = (nearestTime - currentTime) / MICRO_SECONDS;
+ s_select_time.tv_usec = (nearestTime - currentTime) % MICRO_SECONDS;
+ }
+
+ return &s_select_time;
+}
+
+/*
+ * Find the nearest time and update s_nearest_time
+ */
+void bsc_prepare_timers()
+{
+ struct timer_list *timer, *nearest_timer = NULL;
+ llist_for_each_entry(timer, &timer_list, entry) {
+ if (!nearest_timer || TIME_SMALLER(timer->timeout, nearest_timer->timeout)) {
+ nearest_timer = timer;
+ }
+ }
+
+ if (nearest_timer) {
+ s_nearest_time = nearest_timer->timeout;
+ } else {
+ memset(&s_nearest_time, 0, sizeof(struct timeval));
+ }
+}
+
+/*
+ * fire all timers... and remove them
+ */
+int bsc_update_timers()
+{
+ struct timeval current_time;
+ struct timer_list *timer, *tmp;
+ int work = 0;
+
+ gettimeofday(&current_time, NULL);
+
+ /*
+ * The callbacks might mess with our list and in this case
+ * even llist_for_each_entry_safe is not safe to use. To allow
+ * del_timer, add_timer, schedule_timer to be called from within
+ * the callback we jump through some loops.
+ *
+ * First we set the handled flag of each active timer to zero,
+ * then we iterate over the list and execute the callbacks. As the
+ * list might have been changed (specially the next) from within
+ * the callback we have to start over again. Once every callback
+ * is dispatched we will remove the non-active from the list.
+ *
+ * TODO: If this is a performance issue we can poison a global
+ * variable in add_timer and del_timer and only then restart.
+ */
+ llist_for_each_entry(timer, &timer_list, entry) {
+ timer->handled = 0;
+ }
+
+restart:
+ llist_for_each_entry(timer, &timer_list, entry) {
+ if (!timer->handled && TIME_SMALLER(timer->timeout, current_time)) {
+ timer->handled = 1;
+ timer->active = 0;
+ (*timer->cb)(timer->data);
+ work = 1;
+ goto restart;
+ }
+ }
+
+ llist_for_each_entry_safe(timer, tmp, &timer_list, entry) {
+ timer->handled = 0;
+ if (!timer->active) {
+ bsc_del_timer(timer);
+ }
+ }
+
+ return work;
+}