[PATCH 6/7][RFC] netfilter: xt_IDLETIMER: Add new netlink msg type

From: John Stultz
Date: Fri Sep 21 2012 - 22:11:11 EST


From: JP Abgrall <jpa@xxxxxxxxxx>

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: netdev@xxxxxxxxxxxxxxx
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>
---
include/linux/netfilter/xt_IDLETIMER.h | 8 ++++
net/netfilter/xt_IDLETIMER.c | 78 +++++++++++++++++++++++++++++---
2 files changed, 79 insertions(+), 7 deletions(-)

diff --git a/include/linux/netfilter/xt_IDLETIMER.h b/include/linux/netfilter/xt_IDLETIMER.h
index 208ae93..faaa28b 100644
--- a/include/linux/netfilter/xt_IDLETIMER.h
+++ b/include/linux/netfilter/xt_IDLETIMER.h
@@ -4,6 +4,7 @@
* Header file for Xtables timer target module.
*
* Copyright (C) 2004, 2010 Nokia Corporation
+ *
* Written by Timo Teras <ext-timo.teras@xxxxxxxxx>
*
* Converted to x_tables and forward-ported to 2.6.34
@@ -32,12 +33,19 @@
#include <linux/types.h>

#define MAX_IDLETIMER_LABEL_SIZE 28
+#define NLMSG_MAX_SIZE 64
+
+#define NL_EVENT_TYPE_INACTIVE 0
+#define NL_EVENT_TYPE_ACTIVE 1

struct idletimer_tg_info {
__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 __attribute__((aligned(8)));
};
diff --git a/net/netfilter/xt_IDLETIMER.c b/net/netfilter/xt_IDLETIMER.c
index f407ebc1..df91e26 100644
--- a/net/netfilter/xt_IDLETIMER.c
+++ b/net/netfilter/xt_IDLETIMER.c
@@ -5,6 +5,7 @@
* After timer expires a kevent will be sent.
*
* Copyright (C) 2004, 2010 Nokia Corporation
+ *
* Written by Timo Teras <ext-timo.teras@xxxxxxxxx>
*
* Converted to x_tables and reworked for upstream inclusion
@@ -38,8 +39,10 @@
#include <linux/netfilter/xt_IDLETIMER.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 idletimer_tg_attr {
struct attribute attr;
@@ -56,6 +59,8 @@ 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 +68,32 @@ 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 +114,7 @@ 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 +124,15 @@ 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 +141,9 @@ 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)
@@ -113,6 +152,7 @@ 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);
}

@@ -145,6 +185,8 @@ static int idletimer_tg_create(struct idletimer_tg_info *info)
setup_timer(&info->timer->timer, idletimer_tg_expired,
(unsigned long) info->timer);
info->timer->refcnt = 1;
+ info->timer->send_nl_msg = (info->send_nl_msg == 0) ? false : true;
+ info->timer->active = true;

mod_timer(&info->timer->timer,
msecs_to_jiffies(info->timeout * 1000) + jiffies);
@@ -168,14 +210,24 @@ static unsigned int idletimer_tg_target(struct sk_buff *skb,
const struct xt_action_param *par)
{
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);

BUG_ON(!info->timer);

+ info->timer->active = true;
+
+ if (time_before(info->timer->timer.expires, now)) {
+ schedule_work(&info->timer->work);
+ pr_debug("Starting timer %s (Expired, Jiffies): %lu, %lu\n",
+ info->label, info->timer->timer.expires, now);
+ }
+
+ /* TODO: Avoid modifying timers on each packet */
mod_timer(&info->timer->timer,
- msecs_to_jiffies(info->timeout * 1000) + jiffies);
+ msecs_to_jiffies(info->timeout * 1000) + now);

return XT_CONTINUE;
}
@@ -184,8 +236,9 @@ static int idletimer_tg_checkentry(const struct xt_tgchk_param *par)
{
struct idletimer_tg_info *info = par->targinfo;
int ret;
+ unsigned long now = jiffies;

- pr_debug("checkentry targinfo%s\n", info->label);
+ pr_debug("checkentry targinfo %s\n", info->label);

if (info->timeout == 0) {
pr_debug("timeout value is zero\n");
@@ -204,8 +257,16 @@ static int idletimer_tg_checkentry(const struct xt_tgchk_param *par)
info->timer = __idletimer_tg_find_by_label(info->label);
if (info->timer) {
info->timer->refcnt++;
+ info->timer->active = true;
+
+ if (time_before(info->timer->timer.expires, now)) {
+ schedule_work(&info->timer->work);
+ pr_debug("Starting Checkentry timer (Expired, Jiffies): %lu, %lu\n",
+ info->timer->timer.expires, now);
+ }
+
mod_timer(&info->timer->timer,
- msecs_to_jiffies(info->timeout * 1000) + jiffies);
+ msecs_to_jiffies(info->timeout * 1000) + now);

pr_debug("increased refcnt of timer %s to %u\n",
info->label, info->timer->refcnt);
@@ -219,6 +280,7 @@ static int idletimer_tg_checkentry(const struct xt_tgchk_param *par)
}

mutex_unlock(&list_mutex);
+
return 0;
}

@@ -240,7 +302,7 @@ static void idletimer_tg_destroy(const struct xt_tgdtor_param *par)
kfree(info->timer);
} else {
pr_debug("decreased refcnt of timer %s to %u\n",
- info->label, info->timer->refcnt);
+ info->label, info->timer->refcnt);
}

mutex_unlock(&list_mutex);
@@ -248,6 +310,7 @@ static void idletimer_tg_destroy(const struct xt_tgdtor_param *par)

static struct xt_target idletimer_tg __read_mostly = {
.name = "IDLETIMER",
+ .revision = 1,
.family = NFPROTO_UNSPEC,
.target = idletimer_tg_target,
.targetsize = sizeof(struct idletimer_tg_info),
@@ -313,3 +376,4 @@ MODULE_DESCRIPTION("Xtables: idle time monitor");
MODULE_LICENSE("GPL v2");
MODULE_ALIAS("ipt_IDLETIMER");
MODULE_ALIAS("ip6t_IDLETIMER");
+MODULE_ALIAS("arpt_IDLETIMER");
--
1.7.9.5

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