protocol.c revision 6ab3d5624e172c553004ecc862bfeac16d9d68b7 
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 1.14 2001/05/18 02:25:49 davem 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/sched.h>
34#include <linux/string.h>
35#include <linux/socket.h>
36#include <linux/in.h>
37#include <linux/inet.h>
38#include <linux/netdevice.h>
39#include <linux/timer.h>
40#include <net/ip.h>
41#include <net/protocol.h>
42#include <linux/skbuff.h>
43#include <net/sock.h>
44#include <net/icmp.h>
45#include <net/udp.h>
46#include <net/ipip.h>
47#include <linux/igmp.h>
48
49struct net_protocol *inet_protos[MAX_INET_PROTOS];
50static DEFINE_SPINLOCK(inet_proto_lock);
51
52/*
53 *	Add a protocol handler to the hash tables
54 */
55
56int inet_add_protocol(struct net_protocol *prot, unsigned char protocol)
57{
58	int hash, ret;
59
60	hash = protocol & (MAX_INET_PROTOS - 1);
61
62	spin_lock_bh(&inet_proto_lock);
63	if (inet_protos[hash]) {
64		ret = -1;
65	} else {
66		inet_protos[hash] = prot;
67		ret = 0;
68	}
69	spin_unlock_bh(&inet_proto_lock);
70
71	return ret;
72}
73
74/*
75 *	Remove a protocol from the hash tables.
76 */
77
78int inet_del_protocol(struct net_protocol *prot, unsigned char protocol)
79{
80	int hash, ret;
81
82	hash = protocol & (MAX_INET_PROTOS - 1);
83
84	spin_lock_bh(&inet_proto_lock);
85	if (inet_protos[hash] == prot) {
86		inet_protos[hash] = NULL;
87		ret = 0;
88	} else {
89		ret = -1;
90	}
91	spin_unlock_bh(&inet_proto_lock);
92
93	synchronize_net();
94
95	return ret;
96}
97
98EXPORT_SYMBOL(inet_add_protocol);
99EXPORT_SYMBOL(inet_del_protocol);
100