livepatch_ipvs_estimator.c

/*
 *  livepatch_ipvs_estimator.c - IP_VS Live Patching
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/livepatch.h>
#include <net/ip_vs.h>


static void estimation_timer_noop(struct timer_list *t)
{
	struct netns_ipvs *ipvs = from_timer(ipvs, t, est_timer);
	mod_timer(&ipvs->est_timer, jiffies + 600*HZ);
        return;
}

static void livepatch_noop(struct netns_ipvs *ipvs /* $rdi */, struct ip_vs_stats *stats)
{
	return;
}

static struct klp_func funcs[] = {
	{
		.old_name = "estimation_timer",
		.new_func =  estimation_timer_noop,
	},
	{
		.old_name = "ip_vs_start_estimator",
		.new_func = livepatch_noop,
	},
	{
		.old_name = "ip_vs_stop_estimator",
		.new_func = livepatch_noop,
	}, { }
};

static struct klp_object objs[] = {
	{
		/* name being NULL means vmlinux */
		.name = "ip_vs",
		.funcs = funcs,
	}, { }
};

static struct klp_patch patch = {
	.mod = THIS_MODULE,
	.objs = objs,
};

static int livepatch_init(void)
{
	int ret;

	ret = klp_register_patch(&patch);
	if (ret) {
		return ret;
	}

	ret = klp_enable_patch(&patch);
	if (ret) {
		WARN_ON(klp_unregister_patch(&patch));
		return ret;
	}
	return 0;
}

static void livepatch_exit(void)
{
	printk(KERN_INFO "ip_vs estimator patch unloaded");
	WARN_ON(klp_unregister_patch(&patch));
}

module_init(livepatch_init);
module_exit(livepatch_exit);
MODULE_LICENSE("GPL");
MODULE_INFO(livepatch, "Y");

Makefile

obj-m := livepatch_ipvs_estimator.o
patch-objs += livepatch_ipvs_estimator.o

all:
	make -C /lib/modules/$(shell uname -r)/build M=$(PWD) modules

clean:
	make -C /lib/modules/$(shell uname -r)/build M=$(PWD) clean