diff options
Diffstat (limited to 'net/netfilter/xt_LED.c')
| -rw-r--r-- | net/netfilter/xt_LED.c | 201 |
1 files changed, 201 insertions, 0 deletions
diff --git a/net/netfilter/xt_LED.c b/net/netfilter/xt_LED.c new file mode 100644 index 000000000..36c9720ad --- /dev/null +++ b/net/netfilter/xt_LED.c @@ -0,0 +1,201 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * xt_LED.c - netfilter target to make LEDs blink upon packet matches + * + * Copyright (C) 2008 Adam Nielsen <a.nielsen@shikadi.net> + */ +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt +#include <linux/module.h> +#include <linux/skbuff.h> +#include <linux/netfilter/x_tables.h> +#include <linux/slab.h> +#include <linux/leds.h> +#include <linux/mutex.h> + +#include <linux/netfilter/xt_LED.h> + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Adam Nielsen <a.nielsen@shikadi.net>"); +MODULE_DESCRIPTION("Xtables: trigger LED devices on packet match"); +MODULE_ALIAS("ipt_LED"); +MODULE_ALIAS("ip6t_LED"); + +static LIST_HEAD(xt_led_triggers); +static DEFINE_MUTEX(xt_led_mutex); + +/* + * This is declared in here (the kernel module) only, to avoid having these + * dependencies in userspace code. This is what xt_led_info.internal_data + * points to. + */ +struct xt_led_info_internal { + struct list_head list; + int refcnt; + char *trigger_id; + struct led_trigger netfilter_led_trigger; + struct timer_list timer; +}; + +#define XT_LED_BLINK_DELAY 50 /* ms */ + +static unsigned int +led_tg(struct sk_buff *skb, const struct xt_action_param *par) +{ + const struct xt_led_info *ledinfo = par->targinfo; + struct xt_led_info_internal *ledinternal = ledinfo->internal_data; + + /* + * If "always blink" is enabled, and there's still some time until the + * LED will switch off, briefly switch it off now. + */ + if ((ledinfo->delay > 0) && ledinfo->always_blink && + timer_pending(&ledinternal->timer)) + led_trigger_blink_oneshot(&ledinternal->netfilter_led_trigger, + XT_LED_BLINK_DELAY, XT_LED_BLINK_DELAY, 1); + else + led_trigger_event(&ledinternal->netfilter_led_trigger, LED_FULL); + + /* If there's a positive delay, start/update the timer */ + if (ledinfo->delay > 0) { + mod_timer(&ledinternal->timer, + jiffies + msecs_to_jiffies(ledinfo->delay)); + + /* Otherwise if there was no delay given, blink as fast as possible */ + } else if (ledinfo->delay == 0) { + led_trigger_event(&ledinternal->netfilter_led_trigger, LED_OFF); + } + + /* else the delay is negative, which means switch on and stay on */ + + return XT_CONTINUE; +} + +static void led_timeout_callback(struct timer_list *t) +{ + struct xt_led_info_internal *ledinternal = from_timer(ledinternal, t, + timer); + + led_trigger_event(&ledinternal->netfilter_led_trigger, LED_OFF); +} + +static struct xt_led_info_internal *led_trigger_lookup(const char *name) +{ + struct xt_led_info_internal *ledinternal; + + list_for_each_entry(ledinternal, &xt_led_triggers, list) { + if (!strcmp(name, ledinternal->netfilter_led_trigger.name)) { + return ledinternal; + } + } + return NULL; +} + +static int led_tg_check(const struct xt_tgchk_param *par) +{ + struct xt_led_info *ledinfo = par->targinfo; + struct xt_led_info_internal *ledinternal; + int err; + + if (ledinfo->id[0] == '\0') + return -EINVAL; + + mutex_lock(&xt_led_mutex); + + ledinternal = led_trigger_lookup(ledinfo->id); + if (ledinternal) { + ledinternal->refcnt++; + goto out; + } + + err = -ENOMEM; + ledinternal = kzalloc(sizeof(struct xt_led_info_internal), GFP_KERNEL); + if (!ledinternal) + goto exit_mutex_only; + + ledinternal->trigger_id = kstrdup(ledinfo->id, GFP_KERNEL); + if (!ledinternal->trigger_id) + goto exit_internal_alloc; + + ledinternal->refcnt = 1; + ledinternal->netfilter_led_trigger.name = ledinternal->trigger_id; + + err = led_trigger_register(&ledinternal->netfilter_led_trigger); + if (err) { + pr_info_ratelimited("Trigger name is already in use.\n"); + goto exit_alloc; + } + + /* Since the letinternal timer can be shared between multiple targets, + * always set it up, even if the current target does not need it + */ + timer_setup(&ledinternal->timer, led_timeout_callback, 0); + + list_add_tail(&ledinternal->list, &xt_led_triggers); + +out: + mutex_unlock(&xt_led_mutex); + + ledinfo->internal_data = ledinternal; + + return 0; + +exit_alloc: + kfree(ledinternal->trigger_id); + +exit_internal_alloc: + kfree(ledinternal); + +exit_mutex_only: + mutex_unlock(&xt_led_mutex); + + return err; +} + +static void led_tg_destroy(const struct xt_tgdtor_param *par) +{ + const struct xt_led_info *ledinfo = par->targinfo; + struct xt_led_info_internal *ledinternal = ledinfo->internal_data; + + mutex_lock(&xt_led_mutex); + + if (--ledinternal->refcnt) { + mutex_unlock(&xt_led_mutex); + return; + } + + list_del(&ledinternal->list); + + timer_shutdown_sync(&ledinternal->timer); + + led_trigger_unregister(&ledinternal->netfilter_led_trigger); + + mutex_unlock(&xt_led_mutex); + + kfree(ledinternal->trigger_id); + kfree(ledinternal); +} + +static struct xt_target led_tg_reg __read_mostly = { + .name = "LED", + .revision = 0, + .family = NFPROTO_UNSPEC, + .target = led_tg, + .targetsize = sizeof(struct xt_led_info), + .usersize = offsetof(struct xt_led_info, internal_data), + .checkentry = led_tg_check, + .destroy = led_tg_destroy, + .me = THIS_MODULE, +}; + +static int __init led_tg_init(void) +{ + return xt_register_target(&led_tg_reg); +} + +static void __exit led_tg_exit(void) +{ + xt_unregister_target(&led_tg_reg); +} + +module_init(led_tg_init); +module_exit(led_tg_exit); |