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 * Version:	$Id: protocol.c,v 1.1.1.1 2007/08/03 18:53:51 Exp $
9 *
10 * Authors:	Ross Biro
11 *		Fred N. van Kempen, <waltje@uWalt.NL.Mugnet.ORG>
12 *
13 * Fixes:
14 *		Alan Cox	: Ahah! udp icmp errors don't work because
15 *				  udp_err is never called!
16 *		Alan Cox	: Added new fields for init and ready for
17 *				  proper fragmentation (_NO_ 4K limits!)
18 *		Richard Colella	: Hang on hash collision
19 *		Vince Laviano	: Modified inet_del_protocol() to correctly
20 *				  maintain copy bit.
21 *
22 *		This program is free software; you can redistribute it and/or
23 *		modify it under the terms of the GNU General Public License
24 *		as published by the Free Software Foundation; either version
25 *		2 of the License, or (at your option) any later version.
26 */
27
28#include <asm/uaccess.h>
29#include <asm/system.h>
30#include <linux/module.h>
31#include <linux/types.h>
32#include <linux/kernel.h>
33#include <linux/string.h>
34#include <linux/socket.h>
35#include <linux/in.h>
36#include <linux/inet.h>
37#include <linux/netdevice.h>
38#include <linux/timer.h>
39#include <net/ip.h>
40#include <net/protocol.h>
41#include <linux/skbuff.h>
42#include <net/sock.h>
43#include <net/icmp.h>
44#include <net/udp.h>
45#include <net/ipip.h>
46#include <linux/igmp.h>
47
48struct net_protocol *inet_protos[MAX_INET_PROTOS] ____cacheline_aligned_in_smp;
49static DEFINE_SPINLOCK(inet_proto_lock);
50
51/*
52 *	Add a protocol handler to the hash tables
53 */
54
55int inet_add_protocol(struct net_protocol *prot, unsigned char protocol)
56{
57	int hash, ret;
58
59	hash = protocol & (MAX_INET_PROTOS - 1);
60
61	spin_lock_bh(&inet_proto_lock);
62	if (inet_protos[hash]) {
63		ret = -1;
64	} else {
65		inet_protos[hash] = prot;
66		ret = 0;
67	}
68	spin_unlock_bh(&inet_proto_lock);
69
70	return ret;
71}
72
73/*
74 *	Remove a protocol from the hash tables.
75 */
76
77int inet_del_protocol(struct net_protocol *prot, unsigned char protocol)
78{
79	int hash, ret;
80
81	hash = protocol & (MAX_INET_PROTOS - 1);
82
83	spin_lock_bh(&inet_proto_lock);
84	if (inet_protos[hash] == prot) {
85		inet_protos[hash] = NULL;
86		ret = 0;
87	} else {
88		ret = -1;
89	}
90	spin_unlock_bh(&inet_proto_lock);
91
92	synchronize_net();
93
94	return ret;
95}
96
97EXPORT_SYMBOL(inet_add_protocol);
98EXPORT_SYMBOL(inet_del_protocol);
99