Moved scheduler_t to libhydra.

6 files changed, 503 insertions, 2 deletions

diff --git a/src/libhydra/Android.mk b/src/libhydra/Android.mk
index b94fc7f62..40fa00dff 100644
--- a/src/libhydra/Android.mk
+++ b/src/libhydra/Android.mk
@@ -10,7 +10,8 @@ attributes/attribute_manager.c attributes/attribute_manager.h \
 attributes/mem_pool.c attributes/mem_pool.h \
 processing/jobs/job.h \
 processing/jobs/callback_job.c processing/jobs/callback_job.h \
-processing/processor.c processing/processor.h
+processing/processor.c processing/processor.h \
+processing/scheduler.c processing/scheduler.h
 
 # adding the plugin source files
 
diff --git a/src/libhydra/Makefile.am b/src/libhydra/Makefile.am
index 1d32a121a..1de4aa201 100644
--- a/src/libhydra/Makefile.am
+++ b/src/libhydra/Makefile.am
@@ -8,7 +8,8 @@ attributes/attribute_manager.c attributes/attribute_manager.h \
 attributes/mem_pool.c attributes/mem_pool.h \
 processing/jobs/job.h \
 processing/jobs/callback_job.c processing/jobs/callback_job.h \
-processing/processor.c processing/processor.h
+processing/processor.c processing/processor.h \
+processing/scheduler.c processing/scheduler.h
 
 libhydra_la_LIBADD =
 
diff --git a/src/libhydra/hydra.c b/src/libhydra/hydra.c
index 2f3459517..5418802e8 100644
--- a/src/libhydra/hydra.c
+++ b/src/libhydra/hydra.c
@@ -42,6 +42,7 @@ void libhydra_deinit()
 {
 	private_hydra_t *this = (private_hydra_t*)hydra;
 	this->public.attributes->destroy(this->public.attributes);
+	this->public.scheduler->destroy(this->public.scheduler);
 	this->public.processor->destroy(this->public.processor);
 	free((void*)this->public.daemon);
 	free(this);
@@ -64,6 +65,9 @@ bool libhydra_init(const char *daemon)
 	);
 	hydra = &this->public;
 
+	/* requires hydra->processor */
+	this->public.scheduler = scheduler_create();
+
 	if (lib->integrity &&
 		!lib->integrity->check(lib->integrity, "libhydra", libhydra_init))
 	{
diff --git a/src/libhydra/hydra.h b/src/libhydra/hydra.h
index 78d93bd83..2ae8bba76 100644
--- a/src/libhydra/hydra.h
+++ b/src/libhydra/hydra.h
@@ -39,6 +39,7 @@ typedef struct hydra_t hydra_t;
 
 #include <attributes/attribute_manager.h>
 #include <processing/processor.h>
+#include <processing/scheduler.h>
 
 #include <library.h>
 
@@ -58,6 +59,11 @@ struct hydra_t {
 	processor_t *processor;
 
 	/**
+	 * schedule jobs
+	 */
+	scheduler_t *scheduler;
+
+	/**
 	 * name of the daemon that initialized the library
 	 */
 	const char *daemon;
diff --git a/src/libhydra/processing/scheduler.c b/src/libhydra/processing/scheduler.c
new file mode 100644
index 000000000..8a58e4570
--- /dev/null
+++ b/src/libhydra/processing/scheduler.c
@@ -0,0 +1,359 @@
+/*
+ * Copyright (C) 2008 Tobias Brunner
+ * Copyright (C) 2005-2006 Martin Willi
+ * Copyright (C) 2005 Jan Hutter
+ * Hochschule fuer Technik Rapperswil
+ *
+ * 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.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * 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.
+ */
+
+#include <stdlib.h>
+
+#include "scheduler.h"
+
+#include <hydra.h>
+#include <debug.h>
+#include <processing/processor.h>
+#include <processing/jobs/callback_job.h>
+#include <threading/thread.h>
+#include <threading/condvar.h>
+#include <threading/mutex.h>
+
+/* the initial size of the heap */
+#define HEAP_SIZE_DEFAULT 64
+
+typedef struct event_t event_t;
+
+/**
+ * Event containing a job and a schedule time
+ */
+struct event_t {
+	/**
+	 * Time to fire the event.
+	 */
+	timeval_t time;
+
+	/**
+	 * Every event has its assigned job.
+	 */
+	job_t *job;
+};
+
+/**
+ * destroy an event and its job
+ */
+static void event_destroy(event_t *event)
+{
+	event->job->destroy(event->job);
+	free(event);
+}
+
+typedef struct private_scheduler_t private_scheduler_t;
+
+/**
+ * Private data of a scheduler_t object.
+ */
+struct private_scheduler_t {
+
+	/**
+	 * Public part of a scheduler_t object.
+	 */
+	 scheduler_t public;
+
+	/**
+	 * Job which queues scheduled jobs to the processor.
+	 */
+	callback_job_t *job;
+
+	/**
+	 * The heap in which the events are stored.
+	 */
+	event_t **heap;
+
+	/**
+	 * The size of the heap.
+	 */
+	u_int heap_size;
+
+	/**
+	 * The number of scheduled events.
+	 */
+	u_int event_count;
+
+	/**
+	 * Exclusive access to list
+	 */
+	mutex_t *mutex;
+
+	/**
+	 * Condvar to wait for next job.
+	 */
+	condvar_t *condvar;
+};
+
+/**
+ * Comparse two timevals, return >0 if a > b, <0 if a < b and =0 if equal
+ */
+static int timeval_cmp(timeval_t *a, timeval_t *b)
+{
+	if (a->tv_sec > b->tv_sec)
+	{
+		return 1;
+	}
+	if (a->tv_sec < b->tv_sec)
+	{
+		return -1;
+	}
+	if (a->tv_usec > b->tv_usec)
+	{
+		return 1;
+	}
+	if (a->tv_usec < b->tv_usec)
+	{
+		return -1;
+	}
+	return 0;
+}
+
+/**
+ * Returns the top event without removing it. Returns NULL if the heap is empty.
+ */
+static event_t *peek_event(private_scheduler_t *this)
+{
+	return this->event_count > 0 ? this->heap[1] : NULL;
+}
+
+/**
+ * Removes the top event from the heap and returns it. Returns NULL if the heap
+ * is empty.
+ */
+static event_t *remove_event(private_scheduler_t *this)
+{
+	event_t *event, *top;
+	if (!this->event_count)
+	{
+		return NULL;
+	}
+
+	/* store the value to return */
+	event = this->heap[1];
+	/* move the bottom event to the top */
+	top = this->heap[1] = this->heap[this->event_count];
+
+	if (--this->event_count > 1)
+	{
+		/* seep down the top event */
+		u_int position = 1;
+		while ((position << 1) <= this->event_count)
+		{
+			u_int child = position << 1;
+
+			if ((child + 1) <= this->event_count &&
+				timeval_cmp(&this->heap[child + 1]->time,
+							&this->heap[child]->time) < 0)
+			{
+				/* the "right" child is smaller */
+				child++;
+			}
+
+			if (timeval_cmp(&top->time, &this->heap[child]->time) <= 0)
+			{
+				/* the top event fires before the smaller of the two children,
+				 * stop */
+				break;
+			}
+
+			/* swap with the smaller child */
+			this->heap[position] = this->heap[child];
+			position = child;
+		}
+		this->heap[position] = top;
+	}
+	return event;
+}
+
+/**
+ * Get events from the queue and pass it to the processor
+ */
+static job_requeue_t schedule(private_scheduler_t * this)
+{
+	timeval_t now;
+	event_t *event;
+	bool timed = FALSE, oldstate;
+
+	this->mutex->lock(this->mutex);
+
+	time_monotonic(&now);
+
+	if ((event = peek_event(this)) != NULL)
+	{
+		if (timeval_cmp(&now, &event->time) >= 0)
+		{
+			remove_event(this);
+			this->mutex->unlock(this->mutex);
+			DBG2(DBG_JOB, "got event, queuing job for execution");
+			hydra->processor->queue_job(hydra->processor, event->job);
+			free(event);
+			return JOB_REQUEUE_DIRECT;
+		}
+		timersub(&event->time, &now, &now);
+		if (now.tv_sec)
+		{
+			DBG2(DBG_JOB, "next event in %ds %dms, waiting",
+				 now.tv_sec, now.tv_usec/1000);
+		}
+		else
+		{
+			DBG2(DBG_JOB, "next event in %dms, waiting", now.tv_usec/1000);
+		}
+		timed = TRUE;
+	}
+	thread_cleanup_push((thread_cleanup_t)this->mutex->unlock, this->mutex);
+	oldstate = thread_cancelability(TRUE);
+
+	if (timed)
+	{
+		this->condvar->timed_wait_abs(this->condvar, this->mutex, event->time);
+	}
+	else
+	{
+		DBG2(DBG_JOB, "no events, waiting");
+		this->condvar->wait(this->condvar, this->mutex);
+	}
+	thread_cancelability(oldstate);
+	thread_cleanup_pop(TRUE);
+	return JOB_REQUEUE_DIRECT;
+}
+
+/**
+ * Implements scheduler_t.get_job_load
+ */
+static u_int get_job_load(private_scheduler_t *this)
+{
+	int count;
+	this->mutex->lock(this->mutex);
+	count = this->event_count;
+	this->mutex->unlock(this->mutex);
+	return count;
+}
+
+/**
+ * Implements scheduler_t.schedule_job_tv.
+ */
+static void schedule_job_tv(private_scheduler_t *this, job_t *job, timeval_t tv)
+{
+	event_t *event;
+	u_int position;
+
+	event = malloc_thing(event_t);
+	event->job = job;
+	event->time = tv;
+
+	this->mutex->lock(this->mutex);
+
+	this->event_count++;
+	if (this->event_count > this->heap_size)
+	{
+		/* double the size of the heap */
+		this->heap_size <<= 1;
+		this->heap = (event_t**)realloc(this->heap,
+									(this->heap_size + 1) * sizeof(event_t*));
+	}
+	/* "put" the event to the bottom */
+	position = this->event_count;
+
+	/* then bubble it up */
+	while (position > 1 && timeval_cmp(&this->heap[position >> 1]->time,
+									   &event->time) > 0)
+	{
+		/* parent has to be fired after the new event, move up */
+		this->heap[position] = this->heap[position >> 1];
+		position >>= 1;
+	}
+	this->heap[position] = event;
+
+	this->condvar->signal(this->condvar);
+	this->mutex->unlock(this->mutex);
+}
+
+/**
+ * Implements scheduler_t.schedule_job.
+ */
+static void schedule_job(private_scheduler_t *this, job_t *job, u_int32_t s)
+{
+	timeval_t tv;
+
+	time_monotonic(&tv);
+	tv.tv_sec += s;
+
+	schedule_job_tv(this, job, tv);
+}
+
+/**
+ * Implements scheduler_t.schedule_job_ms.
+ */
+static void schedule_job_ms(private_scheduler_t *this, job_t *job, u_int32_t ms)
+{
+	timeval_t tv, add;
+
+	time_monotonic(&tv);
+	add.tv_sec = ms / 1000;
+	add.tv_usec = (ms % 1000) * 1000;
+
+	timeradd(&tv, &add, &tv);
+
+	schedule_job_tv(this, job, tv);
+}
+
+/**
+ * Implementation of scheduler_t.destroy.
+ */
+static void destroy(private_scheduler_t *this)
+{
+	event_t *event;
+	this->job->cancel(this->job);
+	this->condvar->destroy(this->condvar);
+	this->mutex->destroy(this->mutex);
+	while ((event = remove_event(this)) != NULL)
+	{
+		event_destroy(event);
+	}
+	free(this->heap);
+	free(this);
+}
+
+/*
+ * Described in header.
+ */
+scheduler_t * scheduler_create()
+{
+	private_scheduler_t *this = malloc_thing(private_scheduler_t);
+
+	this->public.get_job_load = (u_int (*) (scheduler_t *this)) get_job_load;
+	this->public.schedule_job = (void (*) (scheduler_t *this, job_t *job, u_int32_t s)) schedule_job;
+	this->public.schedule_job_ms = (void (*) (scheduler_t *this, job_t *job, u_int32_t ms)) schedule_job_ms;
+	this->public.schedule_job_tv = (void (*) (scheduler_t *this, job_t *job, timeval_t tv)) schedule_job_tv;
+	this->public.destroy = (void(*)(scheduler_t*)) destroy;
+
+	/* Note: the root of the heap is at index 1 */
+	this->event_count = 0;
+	this->heap_size = HEAP_SIZE_DEFAULT;
+	this->heap = (event_t**)calloc(this->heap_size + 1, sizeof(event_t*));
+
+	this->mutex = mutex_create(MUTEX_TYPE_DEFAULT);
+	this->condvar = condvar_create(CONDVAR_TYPE_DEFAULT);
+
+	this->job = callback_job_create((callback_job_cb_t)schedule, this, NULL, NULL);
+	hydra->processor->queue_job(hydra->processor, (job_t*)this->job);
+
+	return &this->public;
+}
+
diff --git a/src/libhydra/processing/scheduler.h b/src/libhydra/processing/scheduler.h
new file mode 100644
index 000000000..a3439553f
--- /dev/null
+++ b/src/libhydra/processing/scheduler.h
@@ -0,0 +1,130 @@
+/*
+ * Copyright (C) 2009 Tobias Brunner
+ * Copyright (C) 2005-2007 Martin Willi
+ * Copyright (C) 2005 Jan Hutter
+ * Hochschule fuer Technik Rapperswil
+ *
+ * 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.  See <http://www.fsf.org/copyleft/gpl.txt>.
+ *
+ * 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.
+ */
+
+/**
+ * @defgroup scheduler scheduler
+ * @{ @ingroup hprocessing
+ */
+
+#ifndef SCHEDULER_H_
+#define SCHEDULER_H_
+
+typedef struct scheduler_t scheduler_t;
+
+#include <library.h>
+#include <processing/jobs/job.h>
+
+/**
+ * The scheduler queues timed events which are then passed to the processor.
+ *
+ * The scheduler is implemented as a heap. A heap is a special kind of tree-
+ * based data structure that satisfies the following property: if B is a child
+ * node of A, then key(A) >= (or <=) key(B). So either the element with the
+ * greatest (max-heap) or the smallest (min-heap) key is the root of the heap.
+ * We use a min-heap whith the key being the absolute unix time at which an
+ * event is scheduled. So the root is always the event that will fire next.
+ *
+ * An earlier implementation of the scheduler used a sorted linked list to store
+ * the events. That had the advantage that removing the next event was extremely
+ * fast, also, adding an event scheduled before or after all other events was
+ * equally fast (all in O(1)). The problem was, though, that adding an event
+ * in-between got slower, as the number of events grew larger (O(n)).
+ * For each connection there could be several events: IKE-rekey, NAT-keepalive,
+ * retransmissions, expire (half-open), and others. So a gateway that probably
+ * has to handle thousands of concurrent connnections has to be able to queue a
+ * large number of events as fast as possible. Locking makes this even worse, to
+ * provide thread-safety, no events can be processed, while an event is queued,
+ * so making the insertion fast is even more important.
+ *
+ * That's the advantage of the heap. Adding an element to the heap can be
+ * achieved in O(log n) - on the other hand, removing the root node also
+ * requires O(log n) operations. Consider 10000 queued events. Inserting a new
+ * event in the list implementation required up to 10000 comparisons. In the
+ * heap implementation, the worst case is about 13.3 comparisons. That's a
+ * drastic improvement.
+ *
+ * The implementation itself uses a binary tree mapped to a one-based array to
+ * store the elements. This reduces storage overhead and simplifies navigation:
+ * the children of the node at position n are at position 2n and 2n+1 (likewise
+ * the parent node of the node at position n is at position [n/2]). Thus,
+ * navigating up and down the tree is reduced to simple index computations.
+ *
+ * Adding an element to the heap works as follows: The heap is always filled
+ * from left to right, until a row is full, then the next row is filled. Mapped
+ * to an array this gets as simple as putting the new element to the first free
+ * position. In a one-based array that position equals the number of elements
+ * currently stored in the heap. Then the heap property has to be restored, i.e.
+ * the new element has to be "bubbled up" the tree until the parent node's key
+ * is smaller or the element got the new root of the tree.
+ *
+ * Removing the next event from the heap works similarly. The event itself is
+ * the root node and stored at position 1 of the array. After removing it, the
+ * root has to be replaced and the heap property has to be restored. This is
+ * done by moving the bottom element (last row, rightmost element) to the root
+ * and then "seep it down" by swapping it with child nodes until none of the
+ * children has a smaller key or it is again a leaf node.
+ */
+struct scheduler_t {
+
+	/**
+	 * Adds a event to the queue, using a relative time offset in s.
+	 *
+	 * @param job			job to schedule
+	 * @param time			relative time to schedule job, in s
+	 */
+	void (*schedule_job) (scheduler_t *this, job_t *job, u_int32_t s);
+
+	/**
+	 * Adds a event to the queue, using a relative time offset in ms.
+	 *
+	 * @param job			job to schedule
+	 * @param time			relative time to schedule job, in ms
+	 */
+	void (*schedule_job_ms) (scheduler_t *this, job_t *job, u_int32_t ms);
+
+	/**
+	 * Adds a event to the queue, using an absolut time.
+	 *
+	 * The passed timeval should be calculated based on the time_monotonic()
+	 * function.
+	 *
+	 * @param job			job to schedule
+	 * @param time			absolut time to schedule job
+	 */
+	void (*schedule_job_tv) (scheduler_t *this, job_t *job, timeval_t tv);
+
+	/**
+	 * Returns number of jobs scheduled.
+	 *
+	 * @return				number of scheduled jobs
+	 */
+	u_int (*get_job_load) (scheduler_t *this);
+
+	/**
+	 * Destroys a scheduler object.
+	 */
+	void (*destroy) (scheduler_t *this);
+};
+
+/**
+ * Create a scheduler.
+ *
+ * @return		scheduler_t object
+ */
+scheduler_t *scheduler_create(void);
+
+#endif /** SCHEDULER_H_ @}*/