Re: [PATCH 2/2] netfilter: idletimers - add send_nl_msg field

From: Pablo Neira Ayuso
Date: Thu Apr 25 2013 - 21:22:46 EST


Hi Dmitry,

You got some feedback for this patch:

https://patchwork.kernel.org/patch/2333851/

This patch still seem not to address some spots I already mention.

Please, have a look at my previous email and let me know if you have
any question.

Thanks.

On Sun, Apr 21, 2013 at 11:53:14AM +0200, dmitry pervushin wrote:
> 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 <jpa@xxxxxxxxxx>
> Cc: Ashish Sharma <ashishsharma@xxxxxxxxxx>
> Cc: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@xxxxxxxxx>
> Signed-off-by: Ashish Sharma <ashishsharma@xxxxxxxxxx>
> Signed-off-by: JP Abgrall <jpa@xxxxxxxxxx>
> Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx>
> Signed-off-by: dmitry pervushin <dmitry.pervushin@xxxxxxxxxx>
> ---
> 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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