1/* multipath.c: IPV4 multipath algorithm support.
2 *
3 * Copyright (C) 2004, 2005 Einar Lueck <elueck@de.ibm.com>
4 * Copyright (C) 2005 David S. Miller <davem@davemloft.net>
5 */
6
7#include <linux/module.h>
8#include <linux/errno.h>
9#include <linux/netdevice.h>
10#include <linux/spinlock.h>
11
12#include <net/ip_mp_alg.h>
13
14static DEFINE_SPINLOCK(alg_table_lock);
15struct ip_mp_alg_ops *ip_mp_alg_table[IP_MP_ALG_MAX + 1];
16
17int multipath_alg_register(struct ip_mp_alg_ops *ops, enum ip_mp_alg n)
18{
19	struct ip_mp_alg_ops **slot;
20	int err;
21
22	if (n < IP_MP_ALG_NONE || n > IP_MP_ALG_MAX ||
23	    !ops->mp_alg_select_route)
24		return -EINVAL;
25
26	spin_lock(&alg_table_lock);
27	slot = &ip_mp_alg_table[n];
28	if (*slot != NULL) {
29		err = -EBUSY;
30	} else {
31		*slot = ops;
32		err = 0;
33	}
34	spin_unlock(&alg_table_lock);
35
36	return err;
37}
38EXPORT_SYMBOL(multipath_alg_register);
39
40void multipath_alg_unregister(struct ip_mp_alg_ops *ops, enum ip_mp_alg n)
41{
42	struct ip_mp_alg_ops **slot;
43
44	if (n < IP_MP_ALG_NONE || n > IP_MP_ALG_MAX)
45		return;
46
47	spin_lock(&alg_table_lock);
48	slot = &ip_mp_alg_table[n];
49	if (*slot == ops)
50		*slot = NULL;
51	spin_unlock(&alg_table_lock);
52
53	synchronize_net();
54}
55EXPORT_SYMBOL(multipath_alg_unregister);
56