Luciano Coelho | 0902b46 | 2010-06-15 15:04:00 +0200 | [diff] [blame] | 1 | /* |
| 2 | * linux/net/netfilter/xt_IDLETIMER.c |
| 3 | * |
| 4 | * Netfilter module to trigger a timer when packet matches. |
| 5 | * After timer expires a kevent will be sent. |
| 6 | * |
| 7 | * Copyright (C) 2004, 2010 Nokia Corporation |
| 8 | * Written by Timo Teras <ext-timo.teras@nokia.com> |
| 9 | * |
| 10 | * Converted to x_tables and reworked for upstream inclusion |
| 11 | * by Luciano Coelho <luciano.coelho@nokia.com> |
| 12 | * |
| 13 | * Contact: Luciano Coelho <luciano.coelho@nokia.com> |
| 14 | * |
| 15 | * This program is free software; you can redistribute it and/or |
| 16 | * modify it under the terms of the GNU General Public License |
| 17 | * version 2 as published by the Free Software Foundation. |
| 18 | * |
| 19 | * This program is distributed in the hope that it will be useful, but |
| 20 | * WITHOUT ANY WARRANTY; without even the implied warranty of |
| 21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 22 | * General Public License for more details. |
| 23 | * |
| 24 | * You should have received a copy of the GNU General Public License |
| 25 | * along with this program; if not, write to the Free Software |
| 26 | * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA |
| 27 | * 02110-1301 USA |
| 28 | */ |
| 29 | |
| 30 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| 31 | |
| 32 | #include <linux/module.h> |
| 33 | #include <linux/timer.h> |
| 34 | #include <linux/list.h> |
| 35 | #include <linux/mutex.h> |
| 36 | #include <linux/netfilter.h> |
| 37 | #include <linux/netfilter/x_tables.h> |
| 38 | #include <linux/netfilter/xt_IDLETIMER.h> |
Randy Dunlap | 600069d | 2010-06-22 08:13:31 +0200 | [diff] [blame] | 39 | #include <linux/kdev_t.h> |
Luciano Coelho | 0902b46 | 2010-06-15 15:04:00 +0200 | [diff] [blame] | 40 | #include <linux/kobject.h> |
| 41 | #include <linux/workqueue.h> |
| 42 | #include <linux/sysfs.h> |
| 43 | |
| 44 | struct idletimer_tg_attr { |
| 45 | struct attribute attr; |
| 46 | ssize_t (*show)(struct kobject *kobj, |
| 47 | struct attribute *attr, char *buf); |
| 48 | }; |
| 49 | |
| 50 | struct idletimer_tg { |
| 51 | struct list_head entry; |
| 52 | struct timer_list timer; |
| 53 | struct work_struct work; |
| 54 | |
| 55 | struct kobject *kobj; |
| 56 | struct idletimer_tg_attr attr; |
| 57 | |
| 58 | unsigned int refcnt; |
| 59 | }; |
| 60 | |
| 61 | static LIST_HEAD(idletimer_tg_list); |
| 62 | static DEFINE_MUTEX(list_mutex); |
| 63 | |
| 64 | static struct kobject *idletimer_tg_kobj; |
| 65 | |
| 66 | static |
| 67 | struct idletimer_tg *__idletimer_tg_find_by_label(const char *label) |
| 68 | { |
| 69 | struct idletimer_tg *entry; |
| 70 | |
| 71 | BUG_ON(!label); |
| 72 | |
| 73 | list_for_each_entry(entry, &idletimer_tg_list, entry) { |
| 74 | if (!strcmp(label, entry->attr.attr.name)) |
| 75 | return entry; |
| 76 | } |
| 77 | |
| 78 | return NULL; |
| 79 | } |
| 80 | |
| 81 | static ssize_t idletimer_tg_show(struct kobject *kobj, struct attribute *attr, |
| 82 | char *buf) |
| 83 | { |
| 84 | struct idletimer_tg *timer; |
| 85 | unsigned long expires = 0; |
| 86 | |
| 87 | mutex_lock(&list_mutex); |
| 88 | |
| 89 | timer = __idletimer_tg_find_by_label(attr->name); |
| 90 | if (timer) |
| 91 | expires = timer->timer.expires; |
| 92 | |
| 93 | mutex_unlock(&list_mutex); |
| 94 | |
| 95 | if (time_after(expires, jiffies)) |
| 96 | return sprintf(buf, "%u\n", |
| 97 | jiffies_to_msecs(expires - jiffies) / 1000); |
| 98 | |
| 99 | return sprintf(buf, "0\n"); |
| 100 | } |
| 101 | |
| 102 | static void idletimer_tg_work(struct work_struct *work) |
| 103 | { |
| 104 | struct idletimer_tg *timer = container_of(work, struct idletimer_tg, |
| 105 | work); |
| 106 | |
| 107 | sysfs_notify(idletimer_tg_kobj, NULL, timer->attr.attr.name); |
| 108 | } |
| 109 | |
| 110 | static void idletimer_tg_expired(unsigned long data) |
| 111 | { |
| 112 | struct idletimer_tg *timer = (struct idletimer_tg *) data; |
| 113 | |
| 114 | pr_debug("timer %s expired\n", timer->attr.attr.name); |
| 115 | |
| 116 | schedule_work(&timer->work); |
| 117 | } |
| 118 | |
| 119 | static int idletimer_tg_create(struct idletimer_tg_info *info) |
| 120 | { |
| 121 | int ret; |
| 122 | |
| 123 | info->timer = kmalloc(sizeof(*info->timer), GFP_KERNEL); |
| 124 | if (!info->timer) { |
Luciano Coelho | 0902b46 | 2010-06-15 15:04:00 +0200 | [diff] [blame] | 125 | ret = -ENOMEM; |
| 126 | goto out; |
| 127 | } |
| 128 | |
| 129 | info->timer->attr.attr.name = kstrdup(info->label, GFP_KERNEL); |
| 130 | if (!info->timer->attr.attr.name) { |
Luciano Coelho | 0902b46 | 2010-06-15 15:04:00 +0200 | [diff] [blame] | 131 | ret = -ENOMEM; |
| 132 | goto out_free_timer; |
| 133 | } |
| 134 | info->timer->attr.attr.mode = S_IRUGO; |
| 135 | info->timer->attr.show = idletimer_tg_show; |
| 136 | |
| 137 | ret = sysfs_create_file(idletimer_tg_kobj, &info->timer->attr.attr); |
| 138 | if (ret < 0) { |
| 139 | pr_debug("couldn't add file to sysfs"); |
| 140 | goto out_free_attr; |
| 141 | } |
| 142 | |
| 143 | list_add(&info->timer->entry, &idletimer_tg_list); |
| 144 | |
| 145 | setup_timer(&info->timer->timer, idletimer_tg_expired, |
| 146 | (unsigned long) info->timer); |
| 147 | info->timer->refcnt = 1; |
| 148 | |
| 149 | mod_timer(&info->timer->timer, |
| 150 | msecs_to_jiffies(info->timeout * 1000) + jiffies); |
| 151 | |
| 152 | INIT_WORK(&info->timer->work, idletimer_tg_work); |
| 153 | |
| 154 | return 0; |
| 155 | |
| 156 | out_free_attr: |
| 157 | kfree(info->timer->attr.attr.name); |
| 158 | out_free_timer: |
| 159 | kfree(info->timer); |
| 160 | out: |
| 161 | return ret; |
| 162 | } |
| 163 | |
| 164 | /* |
| 165 | * The actual xt_tables plugin. |
| 166 | */ |
| 167 | static unsigned int idletimer_tg_target(struct sk_buff *skb, |
| 168 | const struct xt_action_param *par) |
| 169 | { |
| 170 | const struct idletimer_tg_info *info = par->targinfo; |
| 171 | |
| 172 | pr_debug("resetting timer %s, timeout period %u\n", |
| 173 | info->label, info->timeout); |
| 174 | |
| 175 | BUG_ON(!info->timer); |
| 176 | |
| 177 | mod_timer(&info->timer->timer, |
| 178 | msecs_to_jiffies(info->timeout * 1000) + jiffies); |
| 179 | |
| 180 | return XT_CONTINUE; |
| 181 | } |
| 182 | |
| 183 | static int idletimer_tg_checkentry(const struct xt_tgchk_param *par) |
| 184 | { |
| 185 | struct idletimer_tg_info *info = par->targinfo; |
| 186 | int ret; |
| 187 | |
| 188 | pr_debug("checkentry targinfo%s\n", info->label); |
| 189 | |
| 190 | if (info->timeout == 0) { |
| 191 | pr_debug("timeout value is zero\n"); |
| 192 | return -EINVAL; |
| 193 | } |
| 194 | |
| 195 | if (info->label[0] == '\0' || |
| 196 | strnlen(info->label, |
| 197 | MAX_IDLETIMER_LABEL_SIZE) == MAX_IDLETIMER_LABEL_SIZE) { |
| 198 | pr_debug("label is empty or not nul-terminated\n"); |
| 199 | return -EINVAL; |
| 200 | } |
| 201 | |
| 202 | mutex_lock(&list_mutex); |
| 203 | |
| 204 | info->timer = __idletimer_tg_find_by_label(info->label); |
| 205 | if (info->timer) { |
| 206 | info->timer->refcnt++; |
| 207 | mod_timer(&info->timer->timer, |
| 208 | msecs_to_jiffies(info->timeout * 1000) + jiffies); |
| 209 | |
| 210 | pr_debug("increased refcnt of timer %s to %u\n", |
| 211 | info->label, info->timer->refcnt); |
| 212 | } else { |
| 213 | ret = idletimer_tg_create(info); |
| 214 | if (ret < 0) { |
| 215 | pr_debug("failed to create timer\n"); |
| 216 | mutex_unlock(&list_mutex); |
| 217 | return ret; |
| 218 | } |
| 219 | } |
| 220 | |
| 221 | mutex_unlock(&list_mutex); |
| 222 | return 0; |
| 223 | } |
| 224 | |
| 225 | static void idletimer_tg_destroy(const struct xt_tgdtor_param *par) |
| 226 | { |
| 227 | const struct idletimer_tg_info *info = par->targinfo; |
| 228 | |
| 229 | pr_debug("destroy targinfo %s\n", info->label); |
| 230 | |
| 231 | mutex_lock(&list_mutex); |
| 232 | |
| 233 | if (--info->timer->refcnt == 0) { |
| 234 | pr_debug("deleting timer %s\n", info->label); |
| 235 | |
| 236 | list_del(&info->timer->entry); |
| 237 | del_timer_sync(&info->timer->timer); |
| 238 | sysfs_remove_file(idletimer_tg_kobj, &info->timer->attr.attr); |
| 239 | kfree(info->timer->attr.attr.name); |
| 240 | kfree(info->timer); |
| 241 | } else { |
| 242 | pr_debug("decreased refcnt of timer %s to %u\n", |
| 243 | info->label, info->timer->refcnt); |
| 244 | } |
| 245 | |
| 246 | mutex_unlock(&list_mutex); |
| 247 | } |
| 248 | |
| 249 | static struct xt_target idletimer_tg __read_mostly = { |
| 250 | .name = "IDLETIMER", |
| 251 | .family = NFPROTO_UNSPEC, |
| 252 | .target = idletimer_tg_target, |
| 253 | .targetsize = sizeof(struct idletimer_tg_info), |
| 254 | .checkentry = idletimer_tg_checkentry, |
| 255 | .destroy = idletimer_tg_destroy, |
| 256 | .me = THIS_MODULE, |
| 257 | }; |
| 258 | |
| 259 | static struct class *idletimer_tg_class; |
| 260 | |
| 261 | static struct device *idletimer_tg_device; |
| 262 | |
| 263 | static int __init idletimer_tg_init(void) |
| 264 | { |
| 265 | int err; |
| 266 | |
| 267 | idletimer_tg_class = class_create(THIS_MODULE, "xt_idletimer"); |
| 268 | err = PTR_ERR(idletimer_tg_class); |
| 269 | if (IS_ERR(idletimer_tg_class)) { |
| 270 | pr_debug("couldn't register device class\n"); |
| 271 | goto out; |
| 272 | } |
| 273 | |
| 274 | idletimer_tg_device = device_create(idletimer_tg_class, NULL, |
| 275 | MKDEV(0, 0), NULL, "timers"); |
| 276 | err = PTR_ERR(idletimer_tg_device); |
| 277 | if (IS_ERR(idletimer_tg_device)) { |
| 278 | pr_debug("couldn't register system device\n"); |
| 279 | goto out_class; |
| 280 | } |
| 281 | |
| 282 | idletimer_tg_kobj = &idletimer_tg_device->kobj; |
| 283 | |
| 284 | err = xt_register_target(&idletimer_tg); |
| 285 | if (err < 0) { |
| 286 | pr_debug("couldn't register xt target\n"); |
| 287 | goto out_dev; |
| 288 | } |
| 289 | |
| 290 | return 0; |
| 291 | out_dev: |
| 292 | device_destroy(idletimer_tg_class, MKDEV(0, 0)); |
| 293 | out_class: |
| 294 | class_destroy(idletimer_tg_class); |
| 295 | out: |
| 296 | return err; |
| 297 | } |
| 298 | |
| 299 | static void __exit idletimer_tg_exit(void) |
| 300 | { |
| 301 | xt_unregister_target(&idletimer_tg); |
| 302 | |
| 303 | device_destroy(idletimer_tg_class, MKDEV(0, 0)); |
| 304 | class_destroy(idletimer_tg_class); |
| 305 | } |
| 306 | |
| 307 | module_init(idletimer_tg_init); |
| 308 | module_exit(idletimer_tg_exit); |
| 309 | |
| 310 | MODULE_AUTHOR("Timo Teras <ext-timo.teras@nokia.com>"); |
| 311 | MODULE_AUTHOR("Luciano Coelho <luciano.coelho@nokia.com>"); |
| 312 | MODULE_DESCRIPTION("Xtables: idle time monitor"); |
| 313 | MODULE_LICENSE("GPL v2"); |
Jan Engelhardt | f1e231a | 2011-01-18 06:30:13 +0100 | [diff] [blame] | 314 | MODULE_ALIAS("ipt_IDLETIMER"); |
| 315 | MODULE_ALIAS("ip6t_IDLETIMER"); |