[v2] netfilter: Xtables: idletimer target implementation

Message ID	1275486062-23753-1-git-send-email-luciano.coelho@nokia.com
State	Not Applicable, archived
Delegated to:	David Miller
Headers	show Return-Path: <netdev-owner@vger.kernel.org> From: Luciano Coelho <luciano.coelho@nokia.com> To: netdev@vger.kernel.org Cc: netfilter-devel@vger.kernel.org, kaber@trash.net, jengelh@medozas.de, Timo Teras <timo.teras@iki.fi> Subject: [PATCH v2] netfilter: Xtables: idletimer target implementation Date: Wed, 2 Jun 2010 16:41:02 +0300 Message-Id: <1275486062-23753-1-git-send-email-luciano.coelho@nokia.com> Sender: netdev-owner@vger.kernel.org Precedence: bulk

diff --git a/include/linux/netfilter/xt_IDLETIMER.h b/include/linux/netfilter/xt_IDLETIMER.h new file mode 100644 index 0000000..6e62224 --- /dev/null +++ b/include/linux/netfilter/xt_IDLETIMER.h @@ -0,0 +1,40 @@ +/* + * linux/include/linux/netfilter/xt_IDLETIMER.h + * + * Header file for Xtables timer target module. + * + * Copyright (C) 2004, 2010 Nokia Corporation + * Written by Timo Teras <ext-timo.teras@nokia.com> + * + * Converted to x_tables and forward-ported to 2.6.34 + * 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 + */ + +#ifndef _XT_IDLETIMER_H +#define _XT_IDLETIMER_H + +#define MAX_LABEL_SIZE 32 + +struct idletimer_tg_info { + __u32 timeout; + + char label[MAX_LABEL_SIZE]; +}; + +#endif diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig index 8593a77..413ed24 100644 --- a/net/netfilter/Kconfig +++ b/net/netfilter/Kconfig @@ -424,6 +424,18 @@ config NETFILTER_XT_TARGET_HL since you can easily create immortal packets that loop forever on the network. +config NETFILTER_XT_TARGET_IDLETIMER + tristate "IDLETIMER target support" + depends on NETFILTER_ADVANCED + help + + This option adds the `IDLETIMER' target. Each matching packet + resets the timer associated with label specified when the rule is + added. When the timer expires, it triggers a sysfs notification. + The remaining time for expiration can be read via sysfs. + + To compile it as a module, choose M here. If unsure, say N. + config NETFILTER_XT_TARGET_LED tristate '"LED" target support' depends on LEDS_CLASS && LEDS_TRIGGERS diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile index 14e3a8f..e28420a 100644 --- a/net/netfilter/Makefile +++ b/net/netfilter/Makefile @@ -61,6 +61,7 @@ obj-$(CONFIG_NETFILTER_XT_TARGET_TCPMSS) += xt_TCPMSS.o obj-$(CONFIG_NETFILTER_XT_TARGET_TCPOPTSTRIP) += xt_TCPOPTSTRIP.o obj-$(CONFIG_NETFILTER_XT_TARGET_TEE) += xt_TEE.o obj-$(CONFIG_NETFILTER_XT_TARGET_TRACE) += xt_TRACE.o +obj-$(CONFIG_NETFILTER_XT_TARGET_IDLETIMER) += xt_IDLETIMER.o # matches obj-$(CONFIG_NETFILTER_XT_MATCH_CLUSTER) += xt_cluster.o diff --git a/net/netfilter/xt_IDLETIMER.c b/net/netfilter/xt_IDLETIMER.c new file mode 100644 index 0000000..33fe839 --- /dev/null +++ b/net/netfilter/xt_IDLETIMER.c @@ -0,0 +1,360 @@ +/* + * 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/spinlock.h> +#include <linux/netfilter.h> +#include <linux/netfilter/x_tables.h> +#include <linux/netfilter/xt_IDLETIMER.h> +#include <linux/kobject.h> +#include <linux/workqueue.h> +#include <linux/sysfs.h> + +struct idletimer_tg { + struct list_head entry; + struct timer_list timer; + struct work_struct work; + + struct kobject *kobj; + struct idletimer_tg_attr *attr; + + unsigned int refcnt; +}; + +/* Start with an empty group, we'll add attributes dynamically */ +static struct attribute *idletimer_tg_group_attrs[] = { + NULL, +}; + +static struct attribute_group idletimer_tg_group = { + .attrs = idletimer_tg_group_attrs, +}; + +struct idletimer_tg_attr { + struct attribute attr; + ssize_t (*show)(struct kobject *kobj, + struct attribute *attr, char *buf); +}; + +static LIST_HEAD(idletimer_tg_list); +static DEFINE_SPINLOCK(list_lock); + +static struct kobject *idletimer_tg_kobj; + +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; + + spin_lock_bh(&list_lock); + timer = __idletimer_tg_find_by_label(attr->name); + if (timer) + expires = timer->timer.expires; + spin_unlock_bh(&list_lock); + + if (expires > jiffies) + return sprintf(buf, "%u\n", + jiffies_to_msecs(expires - jiffies) / 1000); + + return sprintf(buf, "0\n"); +} + +static void idletimer_tg_delete(const struct idletimer_tg_info *info) +{ + struct idletimer_tg *timer; + + spin_lock_bh(&list_lock); + timer = __idletimer_tg_find_by_label(info->label); + if (!timer) { + spin_unlock_bh(&list_lock); + return; + } + + if (--timer->refcnt == 0) { + pr_debug("deleting timer %s\n", info->label); + + list_del(&timer->entry); + del_timer_sync(&timer->timer); + spin_unlock_bh(&list_lock); + + sysfs_remove_file_from_group(idletimer_tg_kobj, + &timer->attr->attr, NULL); + kfree(timer->attr->attr.name); + kfree(timer->attr); + kfree(timer); + } else { + spin_unlock_bh(&list_lock); + pr_debug("decreased refcnt of timer %s to %u\n", + info->label, timer->refcnt); + } +} + +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); +} + +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); + + schedule_work(&timer->work); +} + +static +struct idletimer_tg *idletimer_tg_create(const struct idletimer_tg_info *info) +{ + struct idletimer_tg *timer; + struct idletimer_tg_attr *attr; + + attr = kzalloc(sizeof(attr), GFP_KERNEL); + if (!attr) { + pr_debug("couldn't alloc attribute\n"); + return NULL; + } + + attr->attr.name = kstrdup(info->label, GFP_KERNEL); + if (!attr->attr.name) { + pr_debug("couldn't alloc attribute name\n"); + goto out_free_attr; + } + attr->attr.mode = S_IRUGO; + attr->show = idletimer_tg_show; + + if (sysfs_add_file_to_group(idletimer_tg_kobj, &attr->attr, NULL)) { + pr_debug("couldn't add attr to sysfs\n"); + goto out_free_name; + } + + timer = kmalloc(sizeof(struct idletimer_tg), GFP_KERNEL); + if (!timer) { + pr_debug("couldn't alloc timer\n"); + goto out_free_file; + } + + spin_lock_bh(&list_lock); + list_add(&timer->entry, &idletimer_tg_list); + + init_timer(&timer->timer); + setup_timer(&timer->timer, idletimer_tg_expired, (unsigned long) timer); + mod_timer(&timer->timer, + msecs_to_jiffies(info->timeout * 1000) + jiffies); + + timer->attr = attr; + timer->refcnt = 0; + + INIT_WORK(&timer->work, idletimer_tg_work); + spin_unlock_bh(&list_lock); + + return timer; + +out_free_file: + sysfs_remove_file_from_group(idletimer_tg_kobj, + &attr->attr, NULL); +out_free_name: + kfree(attr->attr.name); +out_free_attr: + kfree(attr); + return NULL; +} + +static void idletimer_tg_cleanup(void) +{ + struct idletimer_tg *timer; + + sysfs_remove_group(idletimer_tg_kobj, + &idletimer_tg_group); + + spin_lock(&list_lock); + list_for_each_entry(timer, &idletimer_tg_list, entry) { + pr_debug("deleting timer %s\n", timer->attr->attr.name); + + list_del(&timer->entry); + del_timer_sync(&timer->timer); + kfree(timer->attr->attr.name); + kfree(timer->attr); + kfree(timer); + } + spin_unlock(&list_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; + struct idletimer_tg *timer; + + pr_debug("resetting timer %s, timeout period %u\n", + info->label, info->timeout); + + spin_lock(&list_lock); + timer = __idletimer_tg_find_by_label(info->label); + + BUG_ON(!timer); + + mod_timer(&timer->timer, + msecs_to_jiffies(info->timeout * 1000) + jiffies); + spin_unlock(&list_lock); + + return XT_CONTINUE; +} + +static int idletimer_tg_checkentry(const struct xt_tgchk_param *par) +{ + const struct idletimer_tg_info *info = par->targinfo; + struct idletimer_tg *timer; + + pr_debug("checkentry targinfo %s\n", info->label); + + if (info->timeout == 0) { + pr_debug("timeout value is zero\n"); + return -EINVAL; + } + + if (!info->label || strlen(info->label) == 0) { + pr_debug("label is missing\n"); + return -EINVAL; + } + + spin_lock(&list_lock); + timer = __idletimer_tg_find_by_label(info->label); + if (!timer) { + spin_unlock(&list_lock); + timer = idletimer_tg_create(info); + if (!timer) { + pr_debug("failed to create timer\n"); + return -ENOMEM; + } + spin_lock(&list_lock); + } + + timer->refcnt++; + mod_timer(&timer->timer, + msecs_to_jiffies(info->timeout * 1000) + jiffies); + spin_unlock(&list_lock); + + 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); + + idletimer_tg_delete(info); +} + +static struct xt_target idletimer_tg __read_mostly = { + .name = "IDLETIMER", + .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 int __init idletimer_tg_init(void) +{ + int ret; + + idletimer_tg_kobj = kobject_create_and_add("idletimer", + &THIS_MODULE->mkobj.kobj); + if (!idletimer_tg_kobj) + return -ENOMEM; + + /* + * Maybe adding the kobj under the net class would be cleaner, but at + * the moment the net class only contains interfaces as children. So + * let's keep the idletimer class inside it's own module's object to + * be safe, in case someone expects all objects under net to be + * actual interfaces. + */ + ret = sysfs_create_group(idletimer_tg_kobj, + &idletimer_tg_group); + if (ret < 0) { + pr_debug("failed to create sysfs group"); + return ret; + } + + ret = xt_register_target(&idletimer_tg); + if (ret < 0) { + kobject_put(idletimer_tg_kobj); + idletimer_tg_cleanup(); + return ret; + } + + return 0; +} + +static void __exit idletimer_tg_exit(void) +{ + xt_unregister_target(&idletimer_tg); + kobject_put(idletimer_tg_kobj); + idletimer_tg_cleanup(); +} + +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");

[v2] netfilter: Xtables: idletimer target implementation

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