aboutsummaryrefslogtreecommitdiffstats
path: root/net/llc/llc_core.c
blob: 78167e81dfebdf0be0510df3ff82b7c82da68b38 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
/*
 * llc_core.c - Minimum needed routines for sap handling and module init/exit
 *
 * Copyright (c) 1997 by Procom Technology, Inc.
 * 		 2001-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
 *
 * This program can be redistributed or modified under the terms of the
 * GNU General Public License as published by the Free Software Foundation.
 * This program is distributed without any warranty or implied warranty
 * of merchantability or fitness for a particular purpose.
 *
 * See the GNU General Public License for more details.
 */

#include <linux/module.h>
#include <linux/interrupt.h>
#include <linux/if_ether.h>
#include <linux/netdevice.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/init.h>
#include <net/net_namespace.h>
#include <net/llc.h>

LIST_HEAD(llc_sap_list);
DEFINE_SPINLOCK(llc_sap_list_lock);

/**
 *	llc_sap_alloc - allocates and initializes sap.
 *
 *	Allocates and initializes sap.
 */
static struct llc_sap *llc_sap_alloc(void)
{
	struct llc_sap *sap = kzalloc(sizeof(*sap), GFP_ATOMIC);
	int i;

	if (sap) {
		/* sap->laddr.mac - leave as a null, it's filled by bind */
		sap->state = LLC_SAP_STATE_ACTIVE;
		spin_lock_init(&sap->sk_lock);
		for (i = 0; i < LLC_SK_LADDR_HASH_ENTRIES; i++)
			INIT_HLIST_NULLS_HEAD(&sap->sk_laddr_hash[i], i);
		atomic_set(&sap->refcnt, 1);
	}
	return sap;
}

static struct llc_sap *__llc_sap_find(unsigned char sap_value)
{
	struct llc_sap* sap;

	list_for_each_entry(sap, &llc_sap_list, node)
		if (sap->laddr.lsap == sap_value)
			goto out;
	sap = NULL;
out:
	return sap;
}

/**
 *	llc_sap_find - searchs a SAP in station
 *	@sap_value: sap to be found
 *
 *	Searchs for a sap in the sap list of the LLC's station upon the sap ID.
 *	If the sap is found it will be refcounted and the user will have to do
 *	a llc_sap_put after use.
 *	Returns the sap or %NULL if not found.
 */
struct llc_sap *llc_sap_find(unsigned char sap_value)
{
	struct llc_sap *sap;

	rcu_read_lock_bh();
	sap = __llc_sap_find(sap_value);
	if (sap)
		llc_sap_hold(sap);
	rcu_read_unlock_bh();
	return sap;
}

/**
 *	llc_sap_open - open interface to the upper layers.
 *	@lsap: SAP number.
 *	@func: rcv func for datalink protos
 *
 *	Interface function to upper layer. Each one who wants to get a SAP
 *	(for example NetBEUI) should call this function. Returns the opened
 *	SAP for success, NULL for failure.
 */
struct llc_sap *llc_sap_open(unsigned char lsap,
			     int (*func)(struct sk_buff *skb,
					 struct net_device *dev,
					 struct packet_type *pt,
					 struct net_device *orig_dev))
{
	struct llc_sap *sap = NULL;

	spin_lock_bh(&llc_sap_list_lock);
	if (__llc_sap_find(lsap)) /* SAP already exists */
		goto out;
	sap = llc_sap_alloc();
	if (!sap)
		goto out;
	sap->laddr.lsap = lsap;
	sap->rcv_func	= func;
	list_add_tail_rcu(&sap->node, &llc_sap_list);
out:
	spin_unlock_bh(&llc_sap_list_lock);
	return sap;
}

/**
 *	llc_sap_close - close interface for upper layers.
 *	@sap: SAP to be closed.
 *
 *	Close interface function to upper layer. Each one who wants to
 *	close an open SAP (for example NetBEUI) should call this function.
 * 	Removes this sap from the list of saps in the station and then
 * 	frees the memory for this sap.
 */
void llc_sap_close(struct llc_sap *sap)
{
	WARN_ON(sap->sk_count);

	spin_lock_bh(&llc_sap_list_lock);
	list_del_rcu(&sap->node);
	spin_unlock_bh(&llc_sap_list_lock);

	synchronize_rcu();

	kfree(sap);
}

static struct packet_type llc_packet_type __read_mostly = {
	.type = cpu_to_be16(ETH_P_802_2),
	.func = llc_rcv,
};

static struct packet_type llc_tr_packet_type __read_mostly = {
	.type = cpu_to_be16(ETH_P_TR_802_2),
	.func = llc_rcv,
};

static int __init llc_init(void)
{
	struct net_device *dev;

	dev = first_net_device(&init_net);
	if (dev != NULL)
		dev = next_net_device(dev);

	dev_add_pack(&llc_packet_type);
	dev_add_pack(&llc_tr_packet_type);
	return 0;
}

static void __exit llc_exit(void)
{
	dev_remove_pack(&llc_packet_type);
	dev_remove_pack(&llc_tr_packet_type);
}

module_init(llc_init);
module_exit(llc_exit);

EXPORT_SYMBOL(llc_sap_list);
EXPORT_SYMBOL(llc_sap_list_lock);
EXPORT_SYMBOL(llc_sap_find);
EXPORT_SYMBOL(llc_sap_open);
EXPORT_SYMBOL(llc_sap_close);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Procom 1997, Jay Schullist 2001, Arnaldo C. Melo 2001-2003");
MODULE_DESCRIPTION("LLC IEEE 802.2 core support");