| /* |
| * linux/net/netfilter/xt_HARDIDLETIMER.c |
| * |
| * Netfilter module to trigger a timer when packet matches. |
| * After timer expires a kevent will be sent. |
| * |
| * Copyright (c) 2014-2015, 2017 The Linux Foundation. All rights reserved. |
| * |
| * 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. |
| * |
| */ |
| |
| #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| |
| #include <linux/module.h> |
| #include <linux/timer.h> |
| #include <linux/alarmtimer.h> |
| #include <linux/list.h> |
| #include <linux/mutex.h> |
| #include <linux/netfilter.h> |
| #include <linux/netfilter/x_tables.h> |
| #include <linux/netfilter/xt_HARDIDLETIMER.h> |
| #include <linux/kdev_t.h> |
| #include <linux/kobject.h> |
| #include <linux/skbuff.h> |
| #include <linux/workqueue.h> |
| #include <linux/sysfs.h> |
| #include <net/net_namespace.h> |
| |
| struct hardidletimer_tg_attr { |
| struct attribute attr; |
| ssize_t (*show)(struct kobject *kobj, |
| struct attribute *attr, char *buf); |
| }; |
| |
| struct hardidletimer_tg { |
| struct list_head entry; |
| struct alarm alarm; |
| struct work_struct work; |
| |
| struct kobject *kobj; |
| struct hardidletimer_tg_attr attr; |
| |
| unsigned int refcnt; |
| bool send_nl_msg; |
| bool active; |
| }; |
| |
| static LIST_HEAD(hardidletimer_tg_list); |
| static DEFINE_MUTEX(list_mutex); |
| |
| static struct kobject *hardidletimer_tg_kobj; |
| |
| static void notify_netlink_uevent(const char *iface, |
| struct hardidletimer_tg *timer) |
| { |
| char iface_msg[NLMSG_MAX_SIZE]; |
| char state_msg[NLMSG_MAX_SIZE]; |
| char *envp[] = { iface_msg, state_msg, NULL }; |
| int res; |
| |
| res = snprintf(iface_msg, NLMSG_MAX_SIZE, "INTERFACE=%s", |
| iface); |
| if (res >= NLMSG_MAX_SIZE) { |
| pr_err("message too long (%d)", res); |
| return; |
| } |
| res = snprintf(state_msg, NLMSG_MAX_SIZE, "STATE=%s", |
| timer->active ? "active" : "inactive"); |
| if (res >= NLMSG_MAX_SIZE) { |
| pr_err("message too long (%d)", res); |
| return; |
| } |
| pr_debug("putting nlmsg: <%s> <%s>\n", iface_msg, state_msg); |
| kobject_uevent_env(hardidletimer_tg_kobj, KOBJ_CHANGE, envp); |
| } |
| |
| static |
| struct hardidletimer_tg *__hardidletimer_tg_find_by_label(const char *label) |
| { |
| struct hardidletimer_tg *entry; |
| |
| WARN_ON(!label); |
| |
| list_for_each_entry(entry, &hardidletimer_tg_list, entry) { |
| if (!strcmp(label, entry->attr.attr.name)) |
| return entry; |
| } |
| |
| return NULL; |
| } |
| |
| static ssize_t hardidletimer_tg_show(struct kobject *kobj, |
| struct attribute *attr, char *buf) |
| { |
| struct hardidletimer_tg *timer; |
| ktime_t expires; |
| struct timespec ktimespec; |
| |
| memset(&ktimespec, 0, sizeof(struct timespec)); |
| mutex_lock(&list_mutex); |
| |
| timer = __hardidletimer_tg_find_by_label(attr->name); |
| if (timer) { |
| expires = alarm_expires_remaining(&timer->alarm); |
| ktimespec = ktime_to_timespec(expires); |
| } |
| |
| mutex_unlock(&list_mutex); |
| |
| if (ktimespec.tv_sec >= 0) |
| return snprintf(buf, PAGE_SIZE, "%ld\n", ktimespec.tv_sec); |
| |
| if ((timer) && (timer->send_nl_msg)) |
| return snprintf(buf, PAGE_SIZE, "0 %ld\n", ktimespec.tv_sec); |
| else |
| return snprintf(buf, PAGE_SIZE, "0\n"); |
| } |
| |
| static void hardidletimer_tg_work(struct work_struct *work) |
| { |
| struct hardidletimer_tg *timer = container_of(work, |
| struct hardidletimer_tg, work); |
| |
| sysfs_notify(hardidletimer_tg_kobj, NULL, timer->attr.attr.name); |
| |
| if (timer->send_nl_msg) |
| notify_netlink_uevent(timer->attr.attr.name, timer); |
| } |
| |
| static enum alarmtimer_restart hardidletimer_tg_alarmproc(struct alarm *alarm, |
| ktime_t now) |
| { |
| struct hardidletimer_tg *timer = alarm->data; |
| |
| pr_debug("alarm %s expired\n", timer->attr.attr.name); |
| |
| timer->active = false; |
| schedule_work(&timer->work); |
| return ALARMTIMER_NORESTART; |
| } |
| |
| static int hardidletimer_tg_create(struct hardidletimer_tg_info *info) |
| { |
| int ret; |
| ktime_t tout; |
| |
| 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 = 0444; |
| info->timer->attr.show = hardidletimer_tg_show; |
| |
| ret = sysfs_create_file(hardidletimer_tg_kobj, &info->timer->attr.attr); |
| if (ret < 0) { |
| pr_debug("couldn't add file to sysfs"); |
| goto out_free_attr; |
| } |
| /* notify userspace */ |
| kobject_uevent(hardidletimer_tg_kobj, KOBJ_ADD); |
| |
| list_add(&info->timer->entry, &hardidletimer_tg_list); |
| |
| alarm_init(&info->timer->alarm, ALARM_BOOTTIME, |
| hardidletimer_tg_alarmproc); |
| info->timer->alarm.data = info->timer; |
| info->timer->refcnt = 1; |
| info->timer->send_nl_msg = (info->send_nl_msg == 0) ? false : true; |
| info->timer->active = true; |
| tout = ktime_set(info->timeout, 0); |
| alarm_start_relative(&info->timer->alarm, tout); |
| |
| INIT_WORK(&info->timer->work, hardidletimer_tg_work); |
| |
| return 0; |
| |
| out_free_attr: |
| kfree(info->timer->attr.attr.name); |
| out_free_timer: |
| kfree(info->timer); |
| out: |
| return ret; |
| } |
| |
| /* The actual xt_tables plugin. */ |
| static unsigned int hardidletimer_tg_target(struct sk_buff *skb, |
| const struct xt_action_param *par) |
| { |
| const struct hardidletimer_tg_info *info = par->targinfo; |
| ktime_t tout; |
| |
| pr_debug("resetting timer %s, timeout period %u\n", |
| info->label, info->timeout); |
| |
| WARN_ON(!info->timer); |
| |
| if (!info->timer->active) { |
| schedule_work(&info->timer->work); |
| pr_debug("Starting timer %s\n", info->label); |
| } |
| |
| info->timer->active = true; |
| /* TODO: Avoid modifying timers on each packet */ |
| tout = ktime_set(info->timeout, 0); |
| alarm_start_relative(&info->timer->alarm, tout); |
| |
| return XT_CONTINUE; |
| } |
| |
| static int hardidletimer_tg_checkentry(const struct xt_tgchk_param *par) |
| { |
| struct hardidletimer_tg_info *info = par->targinfo; |
| int ret; |
| ktime_t tout; |
| struct timespec ktimespec; |
| |
| memset(&ktimespec, 0, sizeof(struct timespec)); |
| |
| 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_HARDIDLETIMER_LABEL_SIZE) |
| == MAX_HARDIDLETIMER_LABEL_SIZE) { |
| pr_debug("label is empty or not nul-terminated\n"); |
| return -EINVAL; |
| } |
| |
| mutex_lock(&list_mutex); |
| |
| info->timer = __hardidletimer_tg_find_by_label(info->label); |
| if (info->timer) { |
| info->timer->refcnt++; |
| /* calculate remaining expiry time */ |
| tout = alarm_expires_remaining(&info->timer->alarm); |
| ktimespec = ktime_to_timespec(tout); |
| |
| if (ktimespec.tv_sec > 0) { |
| pr_debug("time_expiry_remaining %ld\n", |
| ktimespec.tv_sec); |
| alarm_start_relative(&info->timer->alarm, tout); |
| } |
| |
| pr_debug("increased refcnt of timer %s to %u\n", |
| info->label, info->timer->refcnt); |
| } else { |
| ret = hardidletimer_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 hardidletimer_tg_destroy(const struct xt_tgdtor_param *par) |
| { |
| const struct hardidletimer_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); |
| alarm_cancel(&info->timer->alarm); |
| cancel_work_sync(&info->timer->work); |
| sysfs_remove_file(hardidletimer_tg_kobj, |
| &info->timer->attr.attr); |
| 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 hardidletimer_tg __read_mostly = { |
| .name = "HARDIDLETIMER", |
| .revision = 1, |
| .family = NFPROTO_UNSPEC, |
| .target = hardidletimer_tg_target, |
| .targetsize = sizeof(struct hardidletimer_tg_info), |
| .checkentry = hardidletimer_tg_checkentry, |
| .destroy = hardidletimer_tg_destroy, |
| .me = THIS_MODULE, |
| }; |
| |
| static struct class *hardidletimer_tg_class; |
| |
| static struct device *hardidletimer_tg_device; |
| |
| static int __init hardidletimer_tg_init(void) |
| { |
| int err; |
| |
| hardidletimer_tg_class = class_create(THIS_MODULE, "xt_hardidletimer"); |
| err = PTR_ERR(hardidletimer_tg_class); |
| if (IS_ERR(hardidletimer_tg_class)) { |
| pr_debug("couldn't register device class\n"); |
| goto out; |
| } |
| |
| hardidletimer_tg_device = device_create(hardidletimer_tg_class, NULL, |
| MKDEV(0, 0), NULL, "timers"); |
| err = PTR_ERR(hardidletimer_tg_device); |
| if (IS_ERR(hardidletimer_tg_device)) { |
| pr_debug("couldn't register system device\n"); |
| goto out_class; |
| } |
| |
| hardidletimer_tg_kobj = &hardidletimer_tg_device->kobj; |
| |
| err = xt_register_target(&hardidletimer_tg); |
| if (err < 0) { |
| pr_debug("couldn't register xt target\n"); |
| goto out_dev; |
| } |
| |
| return 0; |
| out_dev: |
| device_destroy(hardidletimer_tg_class, MKDEV(0, 0)); |
| out_class: |
| class_destroy(hardidletimer_tg_class); |
| out: |
| return err; |
| } |
| |
| static void __exit hardidletimer_tg_exit(void) |
| { |
| xt_unregister_target(&hardidletimer_tg); |
| |
| device_destroy(hardidletimer_tg_class, MKDEV(0, 0)); |
| class_destroy(hardidletimer_tg_class); |
| } |
| |
| module_init(hardidletimer_tg_init); |
| module_exit(hardidletimer_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"); |
| |