xref: /linux/net/ipv6/protocol.c (revision 765532c8aaac624b5f8687af6d319c6a1138a257)
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  *		PF_INET6 protocol dispatch tables.
7  *
8  * Authors:	Pedro Roque	<roque@di.fc.ul.pt>
9  *
10  *		This program is free software; you can redistribute it and/or
11  *		modify it under the terms of the GNU General Public License
12  *		as published by the Free Software Foundation; either version
13  *		2 of the License, or (at your option) any later version.
14  */
15 
16 /*
17  *      Changes:
18  *
19  *      Vince Laviano (vince@cs.stanford.edu)       16 May 2001
20  *      - Removed unused variable 'inet6_protocol_base'
21  *      - Modified inet6_del_protocol() to correctly maintain copy bit.
22  */
23 #include <linux/module.h>
24 #include <linux/netdevice.h>
25 #include <linux/spinlock.h>
26 #include <net/protocol.h>
27 
28 const struct inet6_protocol __rcu *inet6_protos[MAX_INET_PROTOS] __read_mostly;
29 
30 int inet6_add_protocol(const struct inet6_protocol *prot, unsigned char protocol)
31 {
32 	int hash = protocol & (MAX_INET_PROTOS - 1);
33 
34 	return !cmpxchg((const struct inet6_protocol **)&inet6_protos[hash],
35 			NULL, prot) ? 0 : -1;
36 }
37 EXPORT_SYMBOL(inet6_add_protocol);
38 
39 /*
40  *	Remove a protocol from the hash tables.
41  */
42 
43 int inet6_del_protocol(const struct inet6_protocol *prot, unsigned char protocol)
44 {
45 	int ret, hash = protocol & (MAX_INET_PROTOS - 1);
46 
47 	ret = (cmpxchg((const struct inet6_protocol **)&inet6_protos[hash],
48 		       prot, NULL) == prot) ? 0 : -1;
49 
50 	synchronize_net();
51 
52 	return ret;
53 }
54 EXPORT_SYMBOL(inet6_del_protocol);
55