llc_core.c revision 52d58aef5ee460fedd7f250f05e79081019f2c79 
1/*
2 * llc_core.c - Minimum needed routines for sap handling and module init/exit
3 *
4 * Copyright (c) 1997 by Procom Technology, Inc.
5 * 		 2001-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
6 *
7 * This program can be redistributed or modified under the terms of the
8 * GNU General Public License as published by the Free Software Foundation.
9 * This program is distributed without any warranty or implied warranty
10 * of merchantability or fitness for a particular purpose.
11 *
12 * See the GNU General Public License for more details.
13 */
14
15#include <linux/module.h>
16#include <linux/interrupt.h>
17#include <linux/if_ether.h>
18#include <linux/netdevice.h>
19#include <linux/slab.h>
20#include <linux/string.h>
21#include <linux/init.h>
22#include <net/net_namespace.h>
23#include <net/llc.h>
24
25LIST_HEAD(llc_sap_list);
26DEFINE_RWLOCK(llc_sap_list_lock);
27
28/**
29 *	llc_sap_alloc - allocates and initializes sap.
30 *
31 *	Allocates and initializes sap.
32 */
33static struct llc_sap *llc_sap_alloc(void)
34{
35	struct llc_sap *sap = kzalloc(sizeof(*sap), GFP_ATOMIC);
36	int i;
37
38	if (sap) {
39		/* sap->laddr.mac - leave as a null, it's filled by bind */
40		sap->state = LLC_SAP_STATE_ACTIVE;
41		spin_lock_init(&sap->sk_lock);
42		for (i = 0; i < LLC_SK_LADDR_HASH_ENTRIES; i++)
43			INIT_HLIST_NULLS_HEAD(&sap->sk_laddr_hash[i], i);
44		atomic_set(&sap->refcnt, 1);
45	}
46	return sap;
47}
48
49/**
50 *	llc_add_sap - add sap to station list
51 *	@sap: Address of the sap
52 *
53 *	Adds a sap to the LLC's station sap list.
54 */
55static void llc_add_sap(struct llc_sap *sap)
56{
57	list_add_tail(&sap->node, &llc_sap_list);
58}
59
60/**
61 *	llc_del_sap - del sap from station list
62 *	@sap: Address of the sap
63 *
64 *	Removes a sap to the LLC's station sap list.
65 */
66static void llc_del_sap(struct llc_sap *sap)
67{
68	write_lock_bh(&llc_sap_list_lock);
69	list_del(&sap->node);
70	write_unlock_bh(&llc_sap_list_lock);
71}
72
73static struct llc_sap *__llc_sap_find(unsigned char sap_value)
74{
75	struct llc_sap* sap;
76
77	list_for_each_entry(sap, &llc_sap_list, node)
78		if (sap->laddr.lsap == sap_value)
79			goto out;
80	sap = NULL;
81out:
82	return sap;
83}
84
85/**
86 *	llc_sap_find - searchs a SAP in station
87 *	@sap_value: sap to be found
88 *
89 *	Searchs for a sap in the sap list of the LLC's station upon the sap ID.
90 *	If the sap is found it will be refcounted and the user will have to do
91 *	a llc_sap_put after use.
92 *	Returns the sap or %NULL if not found.
93 */
94struct llc_sap *llc_sap_find(unsigned char sap_value)
95{
96	struct llc_sap* sap;
97
98	read_lock_bh(&llc_sap_list_lock);
99	sap = __llc_sap_find(sap_value);
100	if (sap)
101		llc_sap_hold(sap);
102	read_unlock_bh(&llc_sap_list_lock);
103	return sap;
104}
105
106/**
107 *	llc_sap_open - open interface to the upper layers.
108 *	@lsap: SAP number.
109 *	@func: rcv func for datalink protos
110 *
111 *	Interface function to upper layer. Each one who wants to get a SAP
112 *	(for example NetBEUI) should call this function. Returns the opened
113 *	SAP for success, NULL for failure.
114 */
115struct llc_sap *llc_sap_open(unsigned char lsap,
116			     int (*func)(struct sk_buff *skb,
117					 struct net_device *dev,
118					 struct packet_type *pt,
119					 struct net_device *orig_dev))
120{
121	struct llc_sap *sap = NULL;
122
123	write_lock_bh(&llc_sap_list_lock);
124	if (__llc_sap_find(lsap)) /* SAP already exists */
125		goto out;
126	sap = llc_sap_alloc();
127	if (!sap)
128		goto out;
129	sap->laddr.lsap = lsap;
130	sap->rcv_func	= func;
131	llc_add_sap(sap);
132out:
133	write_unlock_bh(&llc_sap_list_lock);
134	return sap;
135}
136
137/**
138 *	llc_sap_close - close interface for upper layers.
139 *	@sap: SAP to be closed.
140 *
141 *	Close interface function to upper layer. Each one who wants to
142 *	close an open SAP (for example NetBEUI) should call this function.
143 * 	Removes this sap from the list of saps in the station and then
144 * 	frees the memory for this sap.
145 */
146void llc_sap_close(struct llc_sap *sap)
147{
148	WARN_ON(sap->sk_count);
149	llc_del_sap(sap);
150	kfree(sap);
151}
152
153static struct packet_type llc_packet_type __read_mostly = {
154	.type = cpu_to_be16(ETH_P_802_2),
155	.func = llc_rcv,
156};
157
158static struct packet_type llc_tr_packet_type __read_mostly = {
159	.type = cpu_to_be16(ETH_P_TR_802_2),
160	.func = llc_rcv,
161};
162
163static int __init llc_init(void)
164{
165	struct net_device *dev;
166
167	dev = first_net_device(&init_net);
168	if (dev != NULL)
169		dev = next_net_device(dev);
170
171	dev_add_pack(&llc_packet_type);
172	dev_add_pack(&llc_tr_packet_type);
173	return 0;
174}
175
176static void __exit llc_exit(void)
177{
178	dev_remove_pack(&llc_packet_type);
179	dev_remove_pack(&llc_tr_packet_type);
180}
181
182module_init(llc_init);
183module_exit(llc_exit);
184
185EXPORT_SYMBOL(llc_sap_list);
186EXPORT_SYMBOL(llc_sap_list_lock);
187EXPORT_SYMBOL(llc_sap_find);
188EXPORT_SYMBOL(llc_sap_open);
189EXPORT_SYMBOL(llc_sap_close);
190
191MODULE_LICENSE("GPL");
192MODULE_AUTHOR("Procom 1997, Jay Schullist 2001, Arnaldo C. Melo 2001-2003");
193MODULE_DESCRIPTION("LLC IEEE 802.2 core support");
194