Send notifications when the label becomes active after an idle period.
Send netlink message notifications in addition to sysfs notifications.
Using a uevent with
      subsystem=xt_idletimer
      INTERFACE=...
      STATE={active,inactive}

This is backport from common android-3.0
commit: beb914e987cbbd368988d2b94a6661cb907c4d5a
with uevent support instead of a new netlink message type.

Cc: JP Abgrall <j...@google.com>
Cc: Ashish Sharma <ashishsha...@google.com>
Cc: Peter P Waskiewicz Jr <peter.p.waskiewicz...@intel.com>
Signed-off-by: Ashish Sharma <ashishsha...@google.com>
Signed-off-by: JP Abgrall <j...@google.com>
Signed-off-by: John Stultz <john.stu...@linaro.org>
Signed-off-by: dmitry pervushin <dmitry.pervus...@linaro.org>
---
 include/uapi/linux/netfilter/xt_IDLETIMER.h |   16 +-
 net/netfilter/xt_IDLETIMER.c                |  234 +++++++++++++++++++--------
 2 files changed, 180 insertions(+), 70 deletions(-)

diff --git a/include/uapi/linux/netfilter/xt_IDLETIMER.h 
b/include/uapi/linux/netfilter/xt_IDLETIMER.h
index 208ae93..e50bc3d 100644
--- a/include/uapi/linux/netfilter/xt_IDLETIMER.h
+++ b/include/uapi/linux/netfilter/xt_IDLETIMER.h
@@ -39,7 +39,21 @@ struct idletimer_tg_info {
        char label[MAX_IDLETIMER_LABEL_SIZE];
 
        /* for kernel module internal use only */
-       struct idletimer_tg *timer __attribute__((aligned(8)));
+       struct idletimer_tg *timer __aligned(8);
 };
 
+#define NL_EVENT_TYPE_INACTIVE 0
+#define NL_EVENT_TYPE_ACTIVE 1
+
+struct idletimer_tg_info_v1 {
+       __u32 timeout;
+
+       char label[MAX_IDLETIMER_LABEL_SIZE];
+
+       /* Use netlink messages for notification in addition to sysfs */
+       __u8 send_nl_msg;
+
+       /* for kernel module internal use only */
+       struct idletimer_tg *timer __aligned(8);
+};
 #endif
diff --git a/net/netfilter/xt_IDLETIMER.c b/net/netfilter/xt_IDLETIMER.c
index 3540c04..6eb25ab 100644
--- a/net/netfilter/xt_IDLETIMER.c
+++ b/net/netfilter/xt_IDLETIMER.c
@@ -41,6 +41,8 @@
 #include <linux/workqueue.h>
 #include <linux/sysfs.h>
 
+#define NLMSG_MAX_SIZE 64
+
 struct idletimer_tg_attr {
        struct attribute attr;
        ssize_t (*show)(struct kobject *kobj,
@@ -56,6 +58,8 @@ struct idletimer_tg {
        struct idletimer_tg_attr attr;
 
        unsigned int refcnt;
+       bool send_nl_msg;
+       bool active;
 };
 
 static LIST_HEAD(idletimer_tg_list);
@@ -63,6 +67,30 @@ static DEFINE_MUTEX(list_mutex);
 
 static struct kobject *idletimer_tg_kobj;
 
+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 *envp[] = { iface_msg, state_msg, NULL };
+       int res;
+
+       res = snprintf(iface_msg, NLMSG_MAX_SIZE, "INTERFACE=%s",
+                      iface);
+       if (NLMSG_MAX_SIZE <= res) {
+               pr_err("message too long (%d)", res);
+               return;
+       }
+       res = snprintf(state_msg, NLMSG_MAX_SIZE, "STATE=%s",
+                      timer->active ? "active" : "inactive");
+       if (NLMSG_MAX_SIZE <= res) {
+               pr_err("message too long (%d)", res);
+               return;
+       }
+       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)
 {
@@ -83,6 +111,7 @@ static ssize_t idletimer_tg_show(struct kobject *kobj, 
struct attribute *attr,
 {
        struct idletimer_tg *timer;
        unsigned long expires = 0;
+       unsigned long now = jiffies;
 
        mutex_lock(&list_mutex);
 
@@ -92,11 +121,15 @@ static ssize_t idletimer_tg_show(struct kobject *kobj, 
struct attribute *attr,
 
        mutex_unlock(&list_mutex);
 
-       if (time_after(expires, jiffies))
+       if (time_after(expires, now))
                return sprintf(buf, "%u\n",
-                              jiffies_to_msecs(expires - jiffies) / 1000);
+                              jiffies_to_msecs(expires - now) / 1000);
 
-       return sprintf(buf, "0\n");
+       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)
@@ -105,6 +138,9 @@ static void idletimer_tg_work(struct work_struct *work)
                                                  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)
@@ -113,50 +149,46 @@ static void idletimer_tg_expired(unsigned long data)
 
        pr_debug("timer %s expired\n", timer->attr.attr.name);
 
+       timer->active = false;
        schedule_work(&timer->work);
 }
 
-static int idletimer_tg_create(struct idletimer_tg_info *info)
+static int idletimer_tg_create(struct idletimer_tg *timer, const char *label,
+               unsigned long timeout, bool send_nl_msg)
 {
        int ret;
 
-       info->timer = kmalloc(sizeof(*info->timer), GFP_KERNEL);
-       if (!info->timer) {
+       timer->attr.attr.name = kstrdup(label, GFP_KERNEL);
+       if (!timer->attr.attr.name) {
                ret = -ENOMEM;
                goto out;
        }
+       timer->attr.attr.mode = S_IRUGO;
+       timer->attr.show = idletimer_tg_show;
 
-       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);
+       ret = sysfs_create_file(idletimer_tg_kobj, &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);
+       list_add(&timer->entry, &idletimer_tg_list);
 
-       setup_timer(&info->timer->timer, idletimer_tg_expired,
-                   (unsigned long) info->timer);
-       info->timer->refcnt = 1;
+       setup_timer(&timer->timer, idletimer_tg_expired,
+                   (unsigned long)timer);
+       timer->active = true;
+       timer->refcnt = 1;
+       timer->send_nl_msg = send_nl_msg;
 
-       mod_timer(&info->timer->timer,
-                 msecs_to_jiffies(info->timeout * 1000) + jiffies);
+       mod_timer(&timer->timer,
+                 msecs_to_jiffies(timeout * 1000) + jiffies);
 
-       INIT_WORK(&info->timer->work, idletimer_tg_work);
+       INIT_WORK(&timer->work, idletimer_tg_work);
 
        return 0;
 
 out_free_attr:
-       kfree(info->timer->attr.attr.name);
-out_free_timer:
-       kfree(info->timer);
+       kfree(timer->attr.attr.name);
 out:
        return ret;
 }
@@ -164,45 +196,60 @@ out:
 /*
  * The actual xt_tables plugin.
  */
-static unsigned int idletimer_tg_target(struct sk_buff *skb,
-                                        const struct xt_action_param *par)
+static unsigned int idletimer_tg_target_do(struct idletimer_tg *timer,
+               const char *label, u32 timeout)
 {
-       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);
+                label, timeout);
 
-       BUG_ON(!info->timer);
+       BUG_ON(!timer);
+       timer->active = true;
 
-       if (time_before(info->timer->timer.expires, now)) {
-               schedule_work(&info->timer->work);
+       if (time_before(timer->timer.expires, now)) {
+               schedule_work(&timer->work);
                pr_debug("Starting timer %s (Expired, Jiffies): %lu, %lu\n",
-                        info->label, info->timer->timer.expires, now);
+                        label, timer->timer.expires, now);
        }
 
        /* TODO: Avoid modifying timers on each packet */
-       mod_timer(&info->timer->timer,
-                 msecs_to_jiffies(info->timeout * 1000) + now);
+       mod_timer(&timer->timer,
+                 msecs_to_jiffies(timeout * 1000) + now);
 
        return XT_CONTINUE;
 }
 
-static int idletimer_tg_checkentry(const struct xt_tgchk_param *par)
+static unsigned int idletimer_tg_target(struct sk_buff *skb,
+                                        const struct xt_action_param *par)
+{
+       const struct idletimer_tg_info *info = par->targinfo;
+       return idletimer_tg_target_do(info->timer, info->label, info->timeout);
+}
+
+static unsigned int idletimer_tg_target_v1(struct sk_buff *skb,
+                                        const struct xt_action_param *par)
+{
+       const struct idletimer_tg_info_v1 *info = par->targinfo;
+       return idletimer_tg_target_do(info->timer, info->label, info->timeout);
+}
+
+static int idletimer_tg_checkentry_do(struct idletimer_tg **timer_ret,
+               const char *label, u32 timeout, bool send_nl_msg)
 {
-       struct idletimer_tg_info *info = par->targinfo;
        int ret;
        unsigned long now = jiffies;
+       struct idletimer_tg *timer;
 
-       pr_debug("checkentry targinfo%s\n", info->label);
+       pr_debug("checkentry targinfo %s\n", label);
 
-       if (info->timeout == 0) {
+       if (timeout == 0) {
                pr_debug("timeout value is zero\n");
                return -EINVAL;
        }
 
-       if (info->label[0] == '\0' ||
-           strnlen(info->label,
+       if (label[0] == '\0' ||
+           strnlen(label,
                    MAX_IDLETIMER_LABEL_SIZE) == MAX_IDLETIMER_LABEL_SIZE) {
                pr_debug("label is empty or not nul-terminated\n");
                return -EINVAL;
@@ -210,22 +257,31 @@ static int idletimer_tg_checkentry(const struct 
xt_tgchk_param *par)
 
        mutex_lock(&list_mutex);
 
-       info->timer = __idletimer_tg_find_by_label(info->label);
-       if (info->timer) {
-               info->timer->refcnt++;
-               if (time_before(info->timer->timer.expires, now)) {
-                       schedule_work(&info->timer->work);
+       timer = __idletimer_tg_find_by_label(label);
+       if (timer) {
+               timer->refcnt++;
+               timer->active = true;
+
+               if (time_before(timer->timer.expires, now)) {
+                       schedule_work(&timer->work);
                        pr_debug("Starting Checkentry timer (Expired, Jiffies): 
%lu, %lu\n",
-                               info->timer->timer.expires, now);
+                               timer->timer.expires, now);
                }
-               mod_timer(&info->timer->timer,
-                         msecs_to_jiffies(info->timeout * 1000) + now);
+               mod_timer(&timer->timer,
+                         msecs_to_jiffies(timeout * 1000) + now);
 
                pr_debug("increased refcnt of timer %s to %u\n",
-                        info->label, info->timer->refcnt);
+                        label, timer->refcnt);
        } else {
-               ret = idletimer_tg_create(info);
+               timer = kmalloc(sizeof(*timer), GFP_KERNEL);
+               if (!timer) {
+                       ret = -ENOMEM;
+                       mutex_unlock(&list_mutex);
+                       return ret;
+               }
+               ret = idletimer_tg_create(timer, label, timeout, send_nl_msg);
                if (ret < 0) {
+                       kfree(timer);
                        pr_debug("failed to create timer\n");
                        mutex_unlock(&list_mutex);
                        return ret;
@@ -233,41 +289,80 @@ static int idletimer_tg_checkentry(const struct 
xt_tgchk_param *par)
        }
 
        mutex_unlock(&list_mutex);
+       *timer_ret = timer;
        return 0;
 }
 
-static void idletimer_tg_destroy(const struct xt_tgdtor_param *par)
+static void idletimer_tg_destroy_do(struct idletimer_tg *timer,
+                                   const char *label)
 {
-       const struct idletimer_tg_info *info = par->targinfo;
-
-       pr_debug("destroy targinfo %s\n", info->label);
+       pr_debug("destroy targinfo %s\n", 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);
-               kfree(info->timer->attr.attr.name);
-               kfree(info->timer);
+       if (--timer->refcnt == 0) {
+               pr_debug("deleting timer %s\n", label);
+
+               list_del(&timer->entry);
+               del_timer_sync(&timer->timer);
+               sysfs_remove_file(idletimer_tg_kobj, &timer->attr.attr);
+               kfree(timer->attr.attr.name);
+               kfree(timer);
        } else {
                pr_debug("decreased refcnt of timer %s to %u\n",
-                        info->label, info->timer->refcnt);
+                        label, timer->refcnt);
        }
-
        mutex_unlock(&list_mutex);
 }
 
-static struct xt_target idletimer_tg __read_mostly = {
+static int idletimer_tg_checkentry(const struct xt_tgchk_param *par)
+{
+       struct idletimer_tg_info *info = par->targinfo;
+
+       return idletimer_tg_checkentry_do(&info->timer, info->label,
+               info->timeout, false);
+}
+
+static int idletimer_tg_checkentry_v1(const struct xt_tgchk_param *par)
+{
+       struct idletimer_tg_info_v1 *info = par->targinfo;
+
+       return idletimer_tg_checkentry_do(&info->timer, info->label,
+               info->timeout, info->send_nl_msg);
+}
+
+static void idletimer_tg_destroy(const struct xt_tgdtor_param *par)
+{
+       const struct idletimer_tg_info *info = par->targinfo;
+       idletimer_tg_destroy_do(info->timer, info->label);
+}
+
+static void idletimer_tg_destroy_v1(const struct xt_tgdtor_param *par)
+{
+       const struct idletimer_tg_info_v1 *info = par->targinfo;
+       idletimer_tg_destroy_do(info->timer, info->label);
+}
+
+static struct xt_target idletimer_tg[] __read_mostly = {
+{
        .name           = "IDLETIMER",
+       .revision       = 0,
        .family         = NFPROTO_UNSPEC,
        .target         = idletimer_tg_target,
        .targetsize     = sizeof(struct idletimer_tg_info),
        .checkentry     = idletimer_tg_checkentry,
        .destroy        = idletimer_tg_destroy,
        .me             = THIS_MODULE,
+},
+{
+       .name           = "IDLETIMER",
+       .revision       = 1,
+       .family         = NFPROTO_UNSPEC,
+       .target         = idletimer_tg_target_v1,
+       .targetsize     = sizeof(struct idletimer_tg_info_v1),
+       .checkentry     = idletimer_tg_checkentry_v1,
+       .destroy        = idletimer_tg_destroy_v1,
+       .me             = THIS_MODULE,
+},
 };
 
 static struct class *idletimer_tg_class;
@@ -295,7 +390,7 @@ static int __init idletimer_tg_init(void)
 
        idletimer_tg_kobj = &idletimer_tg_device->kobj;
 
-       err =  xt_register_target(&idletimer_tg);
+       err = xt_register_targets(idletimer_tg, ARRAY_SIZE(idletimer_tg));
        if (err < 0) {
                pr_debug("couldn't register xt target\n");
                goto out_dev;
@@ -312,7 +407,7 @@ out:
 
 static void __exit idletimer_tg_exit(void)
 {
-       xt_unregister_target(&idletimer_tg);
+       xt_unregister_targets(idletimer_tg, ARRAY_SIZE(idletimer_tg));
 
        device_destroy(idletimer_tg_class, MKDEV(0, 0));
        class_destroy(idletimer_tg_class);
@@ -327,3 +422,4 @@ MODULE_DESCRIPTION("Xtables: idle time monitor");
 MODULE_LICENSE("GPL v2");
 MODULE_ALIAS("ipt_IDLETIMER");
 MODULE_ALIAS("ip6t_IDLETIMER");
+MODULE_ALIAS("arpt_IDLETIMER");
-- 
1.7.10.4

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