1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * INET An implementation of the TCP/IP protocol suite for the LINUX
4 * operating system. INET is implemented using the BSD Socket
5 * interface as the means of communication with the user level.
6 *
7 * INET protocol dispatch tables.
8 *
9 * Authors: Ross Biro
10 * Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
11 *
12 * Fixes:
13 * Alan Cox : Ahah! udp icmp errors don't work because
14 * udp_err is never called!
15 * Alan Cox : Added new fields for init and ready for
16 * proper fragmentation (_NO_ 4K limits!)
17 * Richard Colella : Hang on hash collision
18 * Vince Laviano : Modified inet_del_protocol() to correctly
19 * maintain copy bit.
20 */
21#include <linux/cache.h>
22#include <linux/module.h>
23#include <linux/netdevice.h>
24#include <linux/spinlock.h>
25#include <net/protocol.h>
26
27struct net_protocol __rcu *inet_protos[MAX_INET_PROTOS] __read_mostly;
28EXPORT_SYMBOL(inet_protos);
29const struct net_offload __rcu *inet_offloads[MAX_INET_PROTOS] __read_mostly;
30EXPORT_SYMBOL(inet_offloads);
31
32int inet_add_protocol(const struct net_protocol *prot, unsigned char protocol)
33{
34 return !cmpxchg((const struct net_protocol **)&inet_protos[protocol],
35 NULL, prot) ? 0 : -1;
36}
37EXPORT_SYMBOL(inet_add_protocol);
38
39int inet_add_offload(const struct net_offload *prot, unsigned char protocol)
40{
41 return !cmpxchg((const struct net_offload **)&inet_offloads[protocol],
42 NULL, prot) ? 0 : -1;
43}
44EXPORT_SYMBOL(inet_add_offload);
45
46int inet_del_protocol(const struct net_protocol *prot, unsigned char protocol)
47{
48 int ret;
49
50 ret = (cmpxchg((const struct net_protocol **)&inet_protos[protocol],
51 prot, NULL) == prot) ? 0 : -1;
52
53 synchronize_net();
54
55 return ret;
56}
57EXPORT_SYMBOL(inet_del_protocol);
58
59int inet_del_offload(const struct net_offload *prot, unsigned char protocol)
60{
61 int ret;
62
63 ret = (cmpxchg((const struct net_offload **)&inet_offloads[protocol],
64 prot, NULL) == prot) ? 0 : -1;
65
66 synchronize_net();
67
68 return ret;
69}
70EXPORT_SYMBOL(inet_del_offload);
71

source code of linux/net/ipv4/protocol.c