1 files changed, 513 insertions, 0 deletions

diff --git a/net/netfilter/xt_IDLETIMER.c b/net/netfilter/xt_IDLETIMER.c
new file mode 100644
index 00000000..f6562ba9
--- /dev/null
+++ b/net/netfilter/xt_IDLETIMER.c
@@ -0,0 +1,513 @@
+/*
+ * linux/net/netfilter/xt_IDLETIMER.c
+ *
+ * Netfilter module to trigger a timer when packet matches.
+ * After timer expires a kevent will be sent.
+ *
+ * Copyright (C) 2004, 2010 Nokia Corporation
+ *
+ * Written by Timo Teras <ext-timo.teras@nokia.com>
+ *
+ * Converted to x_tables and reworked for upstream inclusion
+ * by Luciano Coelho <luciano.coelho@nokia.com>
+ *
+ * Contact: Luciano Coelho <luciano.coelho@nokia.com>
+ *
+ * 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., 51 Franklin St, Fifth Floor, Boston, MA
+ * 02110-1301 USA
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/module.h>
+#include <linux/timer.h>
+#include <linux/list.h>
+#include <linux/mutex.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter/x_tables.h>
+#include <linux/netfilter/xt_IDLETIMER.h>
+#include <linux/kdev_t.h>
+#include <linux/kobject.h>
+#include <linux/skbuff.h>
+#include <linux/workqueue.h>
+#include <linux/sysfs.h>
+#include <linux/rtc.h>
+#include <linux/time.h>
+#include <linux/math64.h>
+#include <linux/suspend.h>
+#include <linux/notifier.h>
+#include <net/net_namespace.h>
+
+struct idletimer_tg_attr {
+	struct attribute attr;
+	ssize_t	(*show)(struct kobject *kobj,
+			struct attribute *attr, char *buf);
+};
+
+struct idletimer_tg {
+	struct list_head entry;
+	struct timer_list timer;
+	struct work_struct work;
+
+	struct kobject *kobj;
+	struct idletimer_tg_attr attr;
+
+	struct timespec delayed_timer_trigger;
+	struct timespec last_modified_timer;
+	struct timespec last_suspend_time;
+	struct notifier_block pm_nb;
+
+	int timeout;
+	unsigned int refcnt;
+	bool work_pending;
+	bool send_nl_msg;
+	bool active;
+};
+
+static LIST_HEAD(idletimer_tg_list);
+static DEFINE_MUTEX(list_mutex);
+static DEFINE_SPINLOCK(timestamp_lock);
+
+static struct kobject *idletimer_tg_kobj;
+
+static bool check_for_delayed_trigger(struct idletimer_tg *timer,
+		struct timespec *ts)
+{
+	bool state;
+	struct timespec temp;
+	spin_lock_bh(&timestamp_lock);
+	timer->work_pending = false;
+	if ((ts->tv_sec - timer->last_modified_timer.tv_sec) > timer->timeout ||
+			timer->delayed_timer_trigger.tv_sec != 0) {
+		state = false;
+		temp.tv_sec = timer->timeout;
+		temp.tv_nsec = 0;
+		if (timer->delayed_timer_trigger.tv_sec != 0) {
+			temp = timespec_add(timer->delayed_timer_trigger, temp);
+			ts->tv_sec = temp.tv_sec;
+			ts->tv_nsec = temp.tv_nsec;
+			timer->delayed_timer_trigger.tv_sec = 0;
+			timer->work_pending = true;
+			schedule_work(&timer->work);
+		} else {
+			temp = timespec_add(timer->last_modified_timer, temp);
+			ts->tv_sec = temp.tv_sec;
+			ts->tv_nsec = temp.tv_nsec;
+		}
+	} else {
+		state = timer->active;
+	}
+	spin_unlock_bh(&timestamp_lock);
+	return state;
+}
+
+static void notify_netlink_uevent(const char *iface, struct idletimer_tg *timer)
+{
+	char iface_msg[NLMSG_MAX_SIZE];
+	char state_msg[NLMSG_MAX_SIZE];
+	char timestamp_msg[NLMSG_MAX_SIZE];
+	char *envp[] = { iface_msg, state_msg, timestamp_msg, NULL };
+	int res;
+	struct timespec ts;
+	uint64_t time_ns;
+	bool state;
+
+	res = snprintf(iface_msg, NLMSG_MAX_SIZE, "INTERFACE=%s",
+		       iface);
+	if (NLMSG_MAX_SIZE <= res) {
+		pr_err("message too long (%d)", res);
+		return;
+	}
+
+	get_monotonic_boottime(&ts);
+	state = check_for_delayed_trigger(timer, &ts);
+	res = snprintf(state_msg, NLMSG_MAX_SIZE, "STATE=%s",
+			state ? "active" : "inactive");
+
+	if (NLMSG_MAX_SIZE <= res) {
+		pr_err("message too long (%d)", res);
+		return;
+	}
+
+	time_ns = timespec_to_ns(&ts);
+	res = snprintf(timestamp_msg, NLMSG_MAX_SIZE, "TIME_NS=%llu", time_ns);
+	if (NLMSG_MAX_SIZE <= res) {
+		timestamp_msg[0] = '\0';
+		pr_err("message too long (%d)", res);
+	}
+
+	pr_debug("putting nlmsg: <%s> <%s>\n", iface_msg, state_msg);
+	kobject_uevent_env(idletimer_tg_kobj, KOBJ_CHANGE, envp);
+	return;
+
+
+}
+
+static
+struct idletimer_tg *__idletimer_tg_find_by_label(const char *label)
+{
+	struct idletimer_tg *entry;
+
+	BUG_ON(!label);
+
+	list_for_each_entry(entry, &idletimer_tg_list, entry) {
+		if (!strcmp(label, entry->attr.attr.name))
+			return entry;
+	}
+
+	return NULL;
+}
+
+static ssize_t idletimer_tg_show(struct kobject *kobj, struct attribute *attr,
+				 char *buf)
+{
+	struct idletimer_tg *timer;
+	unsigned long expires = 0;
+	unsigned long now = jiffies;
+
+	mutex_lock(&list_mutex);
+
+	timer =	__idletimer_tg_find_by_label(attr->name);
+	if (timer)
+		expires = timer->timer.expires;
+
+	mutex_unlock(&list_mutex);
+
+	if (time_after(expires, now))
+		return sprintf(buf, "%u\n",
+			       jiffies_to_msecs(expires - now) / 1000);
+
+	if (timer->send_nl_msg)
+		return sprintf(buf, "0 %d\n",
+			jiffies_to_msecs(now - expires) / 1000);
+	else
+		return sprintf(buf, "0\n");
+}
+
+static void idletimer_tg_work(struct work_struct *work)
+{
+	struct idletimer_tg *timer = container_of(work, struct idletimer_tg,
+						  work);
+
+	sysfs_notify(idletimer_tg_kobj, NULL, timer->attr.attr.name);
+
+	if (timer->send_nl_msg)
+		notify_netlink_uevent(timer->attr.attr.name, timer);
+}
+
+static void idletimer_tg_expired(unsigned long data)
+{
+	struct idletimer_tg *timer = (struct idletimer_tg *) data;
+
+	pr_debug("timer %s expired\n", timer->attr.attr.name);
+	spin_lock_bh(&timestamp_lock);
+	timer->active = false;
+	timer->work_pending = true;
+	schedule_work(&timer->work);
+	spin_unlock_bh(&timestamp_lock);
+}
+
+static int idletimer_resume(struct notifier_block *notifier,
+		unsigned long pm_event, void *unused)
+{
+	struct timespec ts;
+	unsigned long time_diff, now = jiffies;
+	struct idletimer_tg *timer = container_of(notifier,
+			struct idletimer_tg, pm_nb);
+	if (!timer)
+		return NOTIFY_DONE;
+	switch (pm_event) {
+	case PM_SUSPEND_PREPARE:
+		get_monotonic_boottime(&timer->last_suspend_time);
+		break;
+	case PM_POST_SUSPEND:
+		spin_lock_bh(&timestamp_lock);
+		if (!timer->active) {
+			spin_unlock_bh(&timestamp_lock);
+			break;
+		}
+		/* since jiffies are not updated when suspended now represents
+		 * the time it would have suspended */
+		if (time_after(timer->timer.expires, now)) {
+			get_monotonic_boottime(&ts);
+			ts = timespec_sub(ts, timer->last_suspend_time);
+			time_diff = timespec_to_jiffies(&ts);
+			if (timer->timer.expires > (time_diff + now)) {
+				mod_timer_pending(&timer->timer,
+						(timer->timer.expires - time_diff));
+			} else {
+				del_timer(&timer->timer);
+				timer->timer.expires = 0;
+				timer->active = false;
+				timer->work_pending = true;
+				schedule_work(&timer->work);
+			}
+		}
+		spin_unlock_bh(&timestamp_lock);
+		break;
+	default:
+		break;
+	}
+	return NOTIFY_DONE;
+}
+
+static int idletimer_tg_create(struct idletimer_tg_info *info)
+{
+	int ret;
+
+	info->timer = kmalloc(sizeof(*info->timer), GFP_KERNEL);
+	if (!info->timer) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	info->timer->attr.attr.name = kstrdup(info->label, GFP_KERNEL);
+	if (!info->timer->attr.attr.name) {
+		ret = -ENOMEM;
+		goto out_free_timer;
+	}
+	info->timer->attr.attr.mode = S_IRUGO;
+	info->timer->attr.show = idletimer_tg_show;
+
+	ret = sysfs_create_file(idletimer_tg_kobj, &info->timer->attr.attr);
+	if (ret < 0) {
+		pr_debug("couldn't add file to sysfs");
+		goto out_free_attr;
+	}
+
+	list_add(&info->timer->entry, &idletimer_tg_list);
+
+	setup_timer(&info->timer->timer, idletimer_tg_expired,
+		    (unsigned long) info->timer);
+	info->timer->refcnt = 1;
+	info->timer->send_nl_msg = (info->send_nl_msg == 0) ? false : true;
+	info->timer->active = true;
+	info->timer->timeout = info->timeout;
+
+	info->timer->delayed_timer_trigger.tv_sec = 0;
+	info->timer->delayed_timer_trigger.tv_nsec = 0;
+	info->timer->work_pending = false;
+	get_monotonic_boottime(&info->timer->last_modified_timer);
+
+	info->timer->pm_nb.notifier_call = idletimer_resume;
+	ret = register_pm_notifier(&info->timer->pm_nb);
+	if (ret)
+		printk(KERN_WARNING "[%s] Failed to register pm notifier %d\n",
+				__func__, ret);
+
+	mod_timer(&info->timer->timer,
+		  msecs_to_jiffies(info->timeout * 1000) + jiffies);
+
+	INIT_WORK(&info->timer->work, idletimer_tg_work);
+
+	return 0;
+
+out_free_attr:
+	kfree(info->timer->attr.attr.name);
+out_free_timer:
+	kfree(info->timer);
+out:
+	return ret;
+}
+
+static void reset_timer(const struct idletimer_tg_info *info)
+{
+	unsigned long now = jiffies;
+	struct idletimer_tg *timer = info->timer;
+	bool timer_prev;
+
+	spin_lock_bh(&timestamp_lock);
+	timer_prev = timer->active;
+	timer->active = true;
+	/* timer_prev is used to guard overflow problem in time_before*/
+	if (!timer_prev || time_before(timer->timer.expires, now)) {
+		pr_debug("Starting Checkentry timer (Expired, Jiffies): %lu, %lu\n",
+				timer->timer.expires, now);
+		/* checks if there is a pending inactive notification*/
+		if (timer->work_pending)
+			timer->delayed_timer_trigger = timer->last_modified_timer;
+		else {
+			timer->work_pending = true;
+			schedule_work(&timer->work);
+		}
+	}
+
+	get_monotonic_boottime(&timer->last_modified_timer);
+	mod_timer(&timer->timer,
+			msecs_to_jiffies(info->timeout * 1000) + now);
+	spin_unlock_bh(&timestamp_lock);
+}
+
+/*
+ * The actual xt_tables plugin.
+ */
+static unsigned int idletimer_tg_target(struct sk_buff *skb,
+					 const struct xt_action_param *par)
+{
+	const struct idletimer_tg_info *info = par->targinfo;
+	unsigned long now = jiffies;
+
+	pr_debug("resetting timer %s, timeout period %u\n",
+		 info->label, info->timeout);
+
+	BUG_ON(!info->timer);
+
+	info->timer->active = true;
+
+	if (time_before(info->timer->timer.expires, now)) {
+		schedule_work(&info->timer->work);
+		pr_debug("Starting timer %s (Expired, Jiffies): %lu, %lu\n",
+			 info->label, info->timer->timer.expires, now);
+	}
+
+	/* TODO: Avoid modifying timers on each packet */
+	reset_timer(info);
+	return XT_CONTINUE;
+}
+
+static int idletimer_tg_checkentry(const struct xt_tgchk_param *par)
+{
+	struct idletimer_tg_info *info = par->targinfo;
+	int ret;
+
+	pr_debug("checkentry targinfo %s\n", info->label);
+
+	if (info->timeout == 0) {
+		pr_debug("timeout value is zero\n");
+		return -EINVAL;
+	}
+
+	if (info->label[0] == '\0' ||
+	    strnlen(info->label,
+		    MAX_IDLETIMER_LABEL_SIZE) == MAX_IDLETIMER_LABEL_SIZE) {
+		pr_debug("label is empty or not nul-terminated\n");
+		return -EINVAL;
+	}
+
+	mutex_lock(&list_mutex);
+
+	info->timer = __idletimer_tg_find_by_label(info->label);
+	if (info->timer) {
+		info->timer->refcnt++;
+		reset_timer(info);
+		pr_debug("increased refcnt of timer %s to %u\n",
+			 info->label, info->timer->refcnt);
+	} else {
+		ret = idletimer_tg_create(info);
+		if (ret < 0) {
+			pr_debug("failed to create timer\n");
+			mutex_unlock(&list_mutex);
+			return ret;
+		}
+	}
+
+	mutex_unlock(&list_mutex);
+
+	return 0;
+}
+
+static void idletimer_tg_destroy(const struct xt_tgdtor_param *par)
+{
+	const struct idletimer_tg_info *info = par->targinfo;
+
+	pr_debug("destroy targinfo %s\n", info->label);
+
+	mutex_lock(&list_mutex);
+
+	if (--info->timer->refcnt == 0) {
+		pr_debug("deleting timer %s\n", info->label);
+
+		list_del(&info->timer->entry);
+		del_timer_sync(&info->timer->timer);
+		sysfs_remove_file(idletimer_tg_kobj, &info->timer->attr.attr);
+		unregister_pm_notifier(&info->timer->pm_nb);
+		kfree(info->timer->attr.attr.name);
+		kfree(info->timer);
+	} else {
+		pr_debug("decreased refcnt of timer %s to %u\n",
+		info->label, info->timer->refcnt);
+	}
+
+	mutex_unlock(&list_mutex);
+}
+
+static struct xt_target idletimer_tg __read_mostly = {
+	.name		= "IDLETIMER",
+	.revision	= 1,
+	.family		= NFPROTO_UNSPEC,
+	.target		= idletimer_tg_target,
+	.targetsize     = sizeof(struct idletimer_tg_info),
+	.checkentry	= idletimer_tg_checkentry,
+	.destroy        = idletimer_tg_destroy,
+	.me		= THIS_MODULE,
+};
+
+static struct class *idletimer_tg_class;
+
+static struct device *idletimer_tg_device;
+
+static int __init idletimer_tg_init(void)
+{
+	int err;
+
+	idletimer_tg_class = class_create(THIS_MODULE, "xt_idletimer");
+	err = PTR_ERR(idletimer_tg_class);
+	if (IS_ERR(idletimer_tg_class)) {
+		pr_debug("couldn't register device class\n");
+		goto out;
+	}
+
+	idletimer_tg_device = device_create(idletimer_tg_class, NULL,
+					    MKDEV(0, 0), NULL, "timers");
+	err = PTR_ERR(idletimer_tg_device);
+	if (IS_ERR(idletimer_tg_device)) {
+		pr_debug("couldn't register system device\n");
+		goto out_class;
+	}
+
+	idletimer_tg_kobj = &idletimer_tg_device->kobj;
+
+	err =  xt_register_target(&idletimer_tg);
+	if (err < 0) {
+		pr_debug("couldn't register xt target\n");
+		goto out_dev;
+	}
+
+	return 0;
+out_dev:
+	device_destroy(idletimer_tg_class, MKDEV(0, 0));
+out_class:
+	class_destroy(idletimer_tg_class);
+out:
+	return err;
+}
+
+static void __exit idletimer_tg_exit(void)
+{
+	xt_unregister_target(&idletimer_tg);
+
+	device_destroy(idletimer_tg_class, MKDEV(0, 0));
+	class_destroy(idletimer_tg_class);
+}
+
+module_init(idletimer_tg_init);
+module_exit(idletimer_tg_exit);
+
+MODULE_AUTHOR("Timo Teras <ext-timo.teras@nokia.com>");
+MODULE_AUTHOR("Luciano Coelho <luciano.coelho@nokia.com>");
+MODULE_DESCRIPTION("Xtables: idle time monitor");
+MODULE_LICENSE("GPL v2");
+MODULE_ALIAS("ipt_IDLETIMER");
+MODULE_ALIAS("ip6t_IDLETIMER");
+MODULE_ALIAS("arpt_IDLETIMER");