1/*
2 * INET		An implementation of the TCP/IP protocol suite for the LINUX
3 *		operating system.  INET is implemented using the  BSD Socket
4 *		interface as the means of communication with the user level.
5 *
6 *		INET protocol dispatch tables.
7 *
8 * Authors:	Ross Biro
9 *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
10 *
11 * Fixes:
12 *		Alan Cox	: Ahah! udp icmp errors don't work because
13 *				  udp_err is never called!
14 *		Alan Cox	: Added new fields for init and ready for
15 *				  proper fragmentation (_NO_ 4K limits!)
16 *		Richard Colella	: Hang on hash collision
17 *		Vince Laviano	: Modified inet_del_protocol() to correctly
18 *				  maintain copy bit.
19 *
20 *		This program is free software; you can redistribute it and/or
21 *		modify it under the terms of the GNU General Public License
22 *		as published by the Free Software Foundation; either version
23 *		2 of the License, or (at your option) any later version.
24 */
25#include <linux/cache.h>
26#include <linux/module.h>
27#include <linux/netdevice.h>
28#include <linux/spinlock.h>
29#include <net/protocol.h>
30
31const struct net_protocol __rcu *inet_protos[MAX_INET_PROTOS] __read_mostly;
32const struct net_offload __rcu *inet_offloads[MAX_INET_PROTOS] __read_mostly;
33
34/*
35 *	Add a protocol handler to the hash tables
36 */
37
38int inet_add_protocol(const struct net_protocol *prot, unsigned char protocol)
39{
40	if (!prot->netns_ok) {
41		pr_err("Protocol %u is not namespace aware, cannot register.\n",
42			protocol);
43		return -EINVAL;
44	}
45
46	return !cmpxchg((const struct net_protocol **)&inet_protos[protocol],
47			NULL, prot) ? 0 : -1;
48}
49EXPORT_SYMBOL(inet_add_protocol);
50
51int inet_add_offload(const struct net_offload *prot, unsigned char protocol)
52{
53	return !cmpxchg((const struct net_offload **)&inet_offloads[protocol],
54			NULL, prot) ? 0 : -1;
55}
56EXPORT_SYMBOL(inet_add_offload);
57
58/*
59 *	Remove a protocol from the hash tables.
60 */
61
62int inet_del_protocol(const struct net_protocol *prot, unsigned char protocol)
63{
64	int ret;
65
66	ret = (cmpxchg((const struct net_protocol **)&inet_protos[protocol],
67		       prot, NULL) == prot) ? 0 : -1;
68
69	synchronize_net();
70
71	return ret;
72}
73EXPORT_SYMBOL(inet_del_protocol);
74
75int inet_del_offload(const struct net_offload *prot, unsigned char protocol)
76{
77	int ret;
78
79	ret = (cmpxchg((const struct net_offload **)&inet_offloads[protocol],
80		       prot, NULL) == prot) ? 0 : -1;
81
82	synchronize_net();
83
84	return ret;
85}
86EXPORT_SYMBOL(inet_del_offload);
87