Merge the changes from the res_timing_timerfd branch.

This provides a new timing interface. In order to use it,
you must be running a Linux with a kernel version of
2.6.25 or newer and glibc 2.8 or newer.

This timing interface is a good alternative if a timing
source is necessary (e.g. for IAX trunking) but DAHDI is
otherwise unnecessary for the system.

For now, this commit contains the actual work done in the
res_timing_timerfd branch. There are no notices in the README
or CHANGES files yet, but they will be added in my next commit.

The timing API of Asterisk also needs to have a bit of work done
with regards to choosing which timing interface to use. This commit
makes the choice a build-time decision, by only allowing one of
the timer interfaces to be chosen in menuselect. It would be preferable
if the choice could be made at run-time, however. The preferred timing
interface could be loaded and tested, and if it does not work, choice
number two may be used instead. That sort of thing. That is beyond
the scope of work in this branch though.



git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@157820 65c4cc65-6c06-0410-ace0-fbb531ad65f3

1 files changed, 271 insertions, 0 deletions

diff --git a/res/res_timing_timerfd.c b/res/res_timing_timerfd.c
new file mode 100644
index 000000000..85af3cc8f
--- /dev/null
+++ b/res/res_timing_timerfd.c
@@ -0,0 +1,271 @@
+/*
+ * Asterisk -- An open source telephony toolkit.
+ *
+ * Copyright (C) 2008, Digium, Inc.
+ *
+ * Mark Michelson <mmichelson@digium.com>
+ *
+ * See http://www.asterisk.org for more information about
+ * the Asterisk project. Please do not directly contact
+ * any of the maintainers of this project for assistance;
+ * the project provides a web site, mailing lists and IRC
+ * channels for your use.
+ *
+ * This program is free software, distributed under the terms of
+ * the GNU General Public License Version 2. See the LICENSE file
+ * at the top of the source tree.
+ */
+
+/*!
+ * \file
+ * \author Mark Michelson <mmichelson@digium.com>
+ *
+ * \brief timerfd timing interface
+ */
+
+/*** MODULEINFO
+	<depend>timerfd</depend>
+	<conflict>res_timing_pthread</conflict>
+	<conflict>res_timing_dahdi</conflict>
+ ***/
+
+#include "asterisk.h"
+
+#include <sys/timerfd.h>
+
+#include "asterisk/module.h"
+#include "asterisk/astobj2.h"
+#include "asterisk/timing.h"
+#include "asterisk/logger.h"
+#include "asterisk/utils.h"
+#include "asterisk/time.h"
+
+static void *timing_funcs_handle;
+
+static int timerfd_timer_open(void);
+static void timerfd_timer_close(int handle);
+static int timerfd_timer_set_rate(int handle, unsigned int rate);
+static void timerfd_timer_ack(int handle, unsigned int quantity);
+static int timerfd_timer_enable_continuous(int handle);
+static int timerfd_timer_disable_continuous(int handle);
+static enum ast_timing_event timerfd_timer_get_event(int handle);
+static unsigned int timerfd_timer_get_max_rate(int handle);
+
+static struct ast_timing_functions timerfd_timing_functions = {
+	.timer_open = timerfd_timer_open,
+	.timer_close = timerfd_timer_close,
+	.timer_set_rate = timerfd_timer_set_rate,
+	.timer_ack = timerfd_timer_ack,
+	.timer_enable_continuous = timerfd_timer_enable_continuous,
+	.timer_disable_continuous = timerfd_timer_disable_continuous,
+	.timer_get_event = timerfd_timer_get_event,
+	.timer_get_max_rate = timerfd_timer_get_max_rate,
+};
+
+static struct ao2_container *timerfd_timers;
+
+#define TIMERFD_TIMER_BUCKETS 563
+#define TIMERFD_MAX_RATE 1000
+
+struct timerfd_timer {
+	int handle;
+	struct itimerspec saved_timer;
+	unsigned int is_continuous:1;
+};
+
+static int timerfd_timer_hash(const void *obj, const int flags)
+{
+	const struct timerfd_timer *timer = obj;
+
+	return timer->handle;
+}
+
+static int timerfd_timer_cmp(void *obj, void *args, void *data, int flags)
+{
+	struct timerfd_timer *timer1 = obj, *timer2 = args;
+	return timer1->handle == timer2->handle ? CMP_MATCH | CMP_STOP : 0;
+}
+
+static void timer_destroy(void *obj)
+{
+	struct timerfd_timer *timer = obj;
+	close(timer->handle);
+}
+
+static int timerfd_timer_open(void)
+{
+	struct timerfd_timer *timer;
+	int handle;
+
+	if (!(timer = ao2_alloc(sizeof(*timer), timer_destroy))) {
+		ast_log(LOG_ERROR, "Could not allocate memory for timerfd_timer structure\n");
+		return -1;
+	}
+	if ((handle = timerfd_create(CLOCK_MONOTONIC, 0)) < 0) {
+		ast_log(LOG_ERROR, "Failed to create timerfd timer: %s\n", strerror(errno));
+		ao2_ref(timer, -1);
+		return -1;
+	}
+
+	timer->handle = handle;
+	ao2_link(timerfd_timers, timer);
+	/* Get rid of the reference from the allocation */
+	ao2_ref(timer, -1);
+	return handle;
+}
+
+static void timerfd_timer_close(int handle)
+{
+	struct timerfd_timer *our_timer, find_helper = {
+		.handle = handle,
+	};
+
+	if (!(our_timer = ao2_find(timerfd_timers, &find_helper, NULL, OBJ_POINTER))) {
+		ast_log(LOG_ERROR, "Couldn't find timer with handle %d\n", handle);
+		return;
+	}
+
+	ao2_unlink(timerfd_timers, our_timer);
+	ao2_ref(our_timer, -1);
+}
+
+static int timerfd_timer_set_rate(int handle, unsigned int rate)
+{
+	struct itimerspec itspec;
+	itspec.it_value.tv_sec = 0;
+	itspec.it_value.tv_nsec = rate ? (long) (1000000000 / rate) : 0L;
+	itspec.it_interval.tv_sec = itspec.it_value.tv_sec;
+	itspec.it_interval.tv_nsec = itspec.it_value.tv_nsec;
+
+	return timerfd_settime(handle, 0, &itspec, NULL);
+}
+
+static void timerfd_timer_ack(int handle, unsigned int quantity)
+{
+	uint64_t expirations;
+	int read_result = 0;
+
+	do {
+		read_result = read(handle, &expirations, sizeof(expirations));
+		if (read_result == -1) {
+			if (errno == EINTR) {
+				continue;
+			} else {
+				ast_log(LOG_ERROR, "Read error: %s\n", strerror(errno));
+				break;
+			}
+		}
+	} while (read_result != sizeof(expirations));
+
+	if (expirations != quantity) {
+		ast_debug(2, "Expected to acknowledge %u ticks but got %llu instead\n", quantity, expirations);
+	}
+}
+
+static int timerfd_timer_enable_continuous(int handle)
+{
+	int res;
+	struct itimerspec continuous_timer = {
+		.it_value.tv_nsec = 1L;
+	};
+	struct timerfd_timer *our_timer, find_helper = {
+		.handle = handle,
+	};
+
+	if (!(our_timer = ao2_find(timerfd_timers, &find_helper, NULL, OBJ_POINTER))) {
+		ast_log(LOG_ERROR, "Couldn't find timer with handle %d\n", handle);
+		return -1;
+	}
+
+	if (our_timer->is_continuous) {
+		/*It's already in continous mode, no need to do
+		 * anything further
+		 */
+		ao2_ref(our_timer, -1);
+		return 0;
+	}
+
+	res = timerfd_settime(handle, 0, &continuous_timer, &our_timer->saved_timer);
+	our_timer->is_continuous = 1;
+	ao2_ref(our_timer, -1);
+	return res;
+}
+
+static int timerfd_timer_disable_continuous(int handle)
+{
+	int res;
+	struct timerfd_timer *our_timer, find_helper = {
+		.handle = handle,
+	};
+
+	if (!(our_timer = ao2_find(timerfd_timers, &find_helper, NULL, OBJ_POINTER))) {
+		ast_log(LOG_ERROR, "Couldn't find timer with handle %d\n", handle);
+		return -1;
+	}
+
+	if(!our_timer->is_continuous) {
+		/* No reason to do anything if we're not
+		 * in continuous mode
+		 */
+		ao2_ref(our_timer, -1);
+		return 0;
+	}
+
+	res = timerfd_settime(handle, 0, &our_timer->saved_timer, NULL);
+	our_timer->is_continuous = 0;
+	memset(&our_timer->saved_timer, 0, sizeof(our_timer->saved_timer));
+	ao2_ref(our_timer, -1);
+	return res;
+}
+
+static enum ast_timing_event timerfd_timer_get_event(int handle)
+{
+	enum ast_timing_event res;
+	struct timerfd_timer *our_timer, find_helper = {
+		.handle = handle,
+	};
+
+	if (!(our_timer = ao2_find(timerfd_timers, &find_helper, NULL, OBJ_POINTER))) {
+		ast_log(LOG_ERROR, "Couldn't find timer with handle %d\n", handle);
+		return -1;
+	}
+
+	if (our_timer->is_continuous) {
+		res = AST_TIMING_EVENT_CONTINUOUS;
+	} else {
+		res = AST_TIMING_EVENT_EXPIRED;
+	}
+
+	ao2_ref(our_timer, -1);
+	return res;
+}
+
+static unsigned int timerfd_timer_get_max_rate(int handle)
+{
+	return TIMERFD_MAX_RATE;
+}
+
+static int load_module(void)
+{
+	if (!(timerfd_timers = ao2_container_alloc(TIMERFD_TIMER_BUCKETS, timerfd_timer_hash, timerfd_timer_cmp))) {
+		return AST_MODULE_LOAD_DECLINE;
+	}
+
+	if (!(timing_funcs_handle = ast_install_timing_functions(&timerfd_timing_functions))) {
+		ao2_ref(timerfd_timers, -1);
+		return AST_MODULE_LOAD_DECLINE;
+	}
+
+	return AST_MODULE_LOAD_SUCCESS;
+}
+
+static int unload_module(void)
+{
+	/* ast_uninstall_timing_functions(timing_funcs_handle); */
+
+	/* This module can not currently be unloaded.  No use count handling is being done. */
+
+	return -1;
+}
+
+AST_MODULE_INFO_STANDARD(ASTERISK_GPL_KEY, "Timerfd Timing Interface");