xref: /linux/net/ipv4/protocol.c (revision 37744feebc086908fd89760650f458ab19071750)
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 
27 struct net_protocol __rcu *inet_protos[MAX_INET_PROTOS] __read_mostly;
28 EXPORT_SYMBOL(inet_protos);
29 const struct net_offload __rcu *inet_offloads[MAX_INET_PROTOS] __read_mostly;
30 EXPORT_SYMBOL(inet_offloads);
31 
32 int inet_add_protocol(const struct net_protocol *prot, unsigned char protocol)
33 {
34 	if (!prot->netns_ok) {
35 		pr_err("Protocol %u is not namespace aware, cannot register.\n",
36 			protocol);
37 		return -EINVAL;
38 	}
39 
40 	return !cmpxchg((const struct net_protocol **)&inet_protos[protocol],
41 			NULL, prot) ? 0 : -1;
42 }
43 EXPORT_SYMBOL(inet_add_protocol);
44 
45 int inet_add_offload(const struct net_offload *prot, unsigned char protocol)
46 {
47 	return !cmpxchg((const struct net_offload **)&inet_offloads[protocol],
48 			NULL, prot) ? 0 : -1;
49 }
50 EXPORT_SYMBOL(inet_add_offload);
51 
52 int inet_del_protocol(const struct net_protocol *prot, unsigned char protocol)
53 {
54 	int ret;
55 
56 	ret = (cmpxchg((const struct net_protocol **)&inet_protos[protocol],
57 		       prot, NULL) == prot) ? 0 : -1;
58 
59 	synchronize_net();
60 
61 	return ret;
62 }
63 EXPORT_SYMBOL(inet_del_protocol);
64 
65 int inet_del_offload(const struct net_offload *prot, unsigned char protocol)
66 {
67 	int ret;
68 
69 	ret = (cmpxchg((const struct net_offload **)&inet_offloads[protocol],
70 		       prot, NULL) == prot) ? 0 : -1;
71 
72 	synchronize_net();
73 
74 	return ret;
75 }
76 EXPORT_SYMBOL(inet_del_offload);
77