[deliverable/linux.git] / net / netfilter / ipvs / ip_vs_pe.c

#define KMSG_COMPONENT "IPVS"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <asm/string.h>
#include <linux/kmod.h>
#include <linux/sysctl.h>

#include <net/ip_vs.h>

/* IPVS pe list */
static LIST_HEAD(ip_vs_pe);

/* semaphore for IPVS PEs. */
static DEFINE_MUTEX(ip_vs_pe_mutex);

/* Get pe in the pe list by name */
struct ip_vs_pe *__ip_vs_pe_getbyname(const char *pe_name)
{
	struct ip_vs_pe *pe;

	IP_VS_DBG(10, "%s(): pe_name \"%s\"\n", __func__,
		  pe_name);

	rcu_read_lock();
	list_for_each_entry_rcu(pe, &ip_vs_pe, n_list) {
		/* Test and get the modules atomically */
		if (pe->module &&
		    !try_module_get(pe->module)) {
			/* This pe is just deleted */
			continue;
		}
		if (strcmp(pe_name, pe->name)==0) {
			/* HIT */
			rcu_read_unlock();
			return pe;
		}
		module_put(pe->module);
	}
	rcu_read_unlock();

	return NULL;
}

/* Lookup pe and try to load it if it doesn't exist */
struct ip_vs_pe *ip_vs_pe_getbyname(const char *name)
{
	struct ip_vs_pe *pe;

	/* Search for the pe by name */
	pe = __ip_vs_pe_getbyname(name);

	/* If pe not found, load the module and search again */
	if (!pe) {
		request_module("ip_vs_pe_%s", name);
		pe = __ip_vs_pe_getbyname(name);
	}

	return pe;
}

/* Register a pe in the pe list */
int register_ip_vs_pe(struct ip_vs_pe *pe)
{
	struct ip_vs_pe *tmp;

	/* increase the module use count */
	ip_vs_use_count_inc();

	mutex_lock(&ip_vs_pe_mutex);
	/* Make sure that the pe with this name doesn't exist
	 * in the pe list.
	 */
	list_for_each_entry(tmp, &ip_vs_pe, n_list) {
		if (strcmp(tmp->name, pe->name) == 0) {
			mutex_unlock(&ip_vs_pe_mutex);
			ip_vs_use_count_dec();
			pr_err("%s(): [%s] pe already existed "
			       "in the system\n", __func__, pe->name);
			return -EINVAL;
		}
	}
	/* Add it into the d-linked pe list */
	list_add_rcu(&pe->n_list, &ip_vs_pe);
	mutex_unlock(&ip_vs_pe_mutex);

	pr_info("[%s] pe registered.\n", pe->name);

	return 0;
}
EXPORT_SYMBOL_GPL(register_ip_vs_pe);

/* Unregister a pe from the pe list */
int unregister_ip_vs_pe(struct ip_vs_pe *pe)
{
	mutex_lock(&ip_vs_pe_mutex);
	/* Remove it from the d-linked pe list */
	list_del_rcu(&pe->n_list);
	mutex_unlock(&ip_vs_pe_mutex);

	/* decrease the module use count */
	ip_vs_use_count_dec();

	pr_info("[%s] pe unregistered.\n", pe->name);

	return 0;
}
EXPORT_SYMBOL_GPL(unregister_ip_vs_pe);
Commit	Line	Data
8be67a66 SH	1	#define KMSG_COMPONENT "IPVS"
	2	#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
	3
	4	#include <linux/module.h>
	5	#include <linux/spinlock.h>
	6	#include <linux/interrupt.h>
	7	#include <asm/string.h>
	8	#include <linux/kmod.h>
	9	#include <linux/sysctl.h>
	10
	11	#include <net/ip_vs.h>
	12
	13	/* IPVS pe list */
	14	static LIST_HEAD(ip_vs_pe);
	15
60b6aa3b JA	16	/* semaphore for IPVS PEs. */
60b6aa3b JA	17	static DEFINE_MUTEX(ip_vs_pe_mutex);
8be67a66	18
8be67a66	19	/* Get pe in the pe list by name */
fe5e7a1e	20	struct ip_vs_pe __ip_vs_pe_getbyname(const char pe_name)
8be67a66 SH	21	{
	22	struct ip_vs_pe *pe;
	23
fe5e7a1e	24	IP_VS_DBG(10, "%s(): pe_name \"%s\"\n", __func__,
8be67a66 SH	25	pe_name);
8be67a66 SH	26
60b6aa3b JA	27	rcu_read_lock();
60b6aa3b JA	28	list_for_each_entry_rcu(pe, &ip_vs_pe, n_list) {
8be67a66 SH	29	/* Test and get the modules atomically */
	30	if (pe->module &&
	31	!try_module_get(pe->module)) {
	32	/* This pe is just deleted */
	33	continue;
	34	}
	35	if (strcmp(pe_name, pe->name)==0) {
	36	/* HIT */
60b6aa3b	37	rcu_read_unlock();
8be67a66 SH	38	return pe;
8be67a66 SH	39	}
982f4051	40	module_put(pe->module);
8be67a66	41	}
60b6aa3b	42	rcu_read_unlock();
8be67a66	43
8be67a66 SH	44	return NULL;
	45	}
	46
	47	/* Lookup pe and try to load it if it doesn't exist */
e9e5eee8	48	struct ip_vs_pe ip_vs_pe_getbyname(const char name)
8be67a66 SH	49	{
	50	struct ip_vs_pe *pe;
	51
	52	/* Search for the pe by name */
e9e5eee8	53	pe = __ip_vs_pe_getbyname(name);
8be67a66 SH	54
	55	/* If pe not found, load the module and search again */
	56	if (!pe) {
	57	request_module("ip_vs_pe_%s", name);
e9e5eee8	58	pe = __ip_vs_pe_getbyname(name);
8be67a66 SH	59	}
	60
	61	return pe;
	62	}
	63
8be67a66 SH	64	/* Register a pe in the pe list */
	65	int register_ip_vs_pe(struct ip_vs_pe *pe)
	66	{
	67	struct ip_vs_pe *tmp;
	68
	69	/* increase the module use count */
	70	ip_vs_use_count_inc();
	71
60b6aa3b	72	mutex_lock(&ip_vs_pe_mutex);
8be67a66 SH	73	/* Make sure that the pe with this name doesn't exist
	74	* in the pe list.
	75	*/
	76	list_for_each_entry(tmp, &ip_vs_pe, n_list) {
	77	if (strcmp(tmp->name, pe->name) == 0) {
60b6aa3b	78	mutex_unlock(&ip_vs_pe_mutex);
8be67a66 SH	79	ip_vs_use_count_dec();
	80	pr_err("%s(): [%s] pe already existed "
	81	"in the system\n", __func__, pe->name);
	82	return -EINVAL;
	83	}
	84	}
	85	/* Add it into the d-linked pe list */
60b6aa3b JA	86	list_add_rcu(&pe->n_list, &ip_vs_pe);
60b6aa3b JA	87	mutex_unlock(&ip_vs_pe_mutex);
8be67a66 SH	88
	89	pr_info("[%s] pe registered.\n", pe->name);
	90
	91	return 0;
	92	}
	93	EXPORT_SYMBOL_GPL(register_ip_vs_pe);
	94
	95	/* Unregister a pe from the pe list */
	96	int unregister_ip_vs_pe(struct ip_vs_pe *pe)
	97	{
60b6aa3b	98	mutex_lock(&ip_vs_pe_mutex);
8be67a66	99	/* Remove it from the d-linked pe list */
60b6aa3b JA	100	list_del_rcu(&pe->n_list);
60b6aa3b JA	101	mutex_unlock(&ip_vs_pe_mutex);
8be67a66 SH	102
	103	/* decrease the module use count */
	104	ip_vs_use_count_dec();
	105
	106	pr_info("[%s] pe unregistered.\n", pe->name);
	107
	108	return 0;
	109	}
	110	EXPORT_SYMBOL_GPL(unregister_ip_vs_pe);