llc_core.c revision 7562f876cd93800f2f8c89445f2a563590b24e09 
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/llc.h>
23
24LIST_HEAD(llc_sap_list);
25DEFINE_RWLOCK(llc_sap_list_lock);
26
27unsigned char llc_station_mac_sa[ETH_ALEN];
28
29/**
30 *	llc_sap_alloc - allocates and initializes sap.
31 *
32 *	Allocates and initializes sap.
33 */
34static struct llc_sap *llc_sap_alloc(void)
35{
36	struct llc_sap *sap = kzalloc(sizeof(*sap), GFP_ATOMIC);
37
38	if (sap) {
39		sap->state = LLC_SAP_STATE_ACTIVE;
40		memcpy(sap->laddr.mac, llc_station_mac_sa, ETH_ALEN);
41		rwlock_init(&sap->sk_list.lock);
42		atomic_set(&sap->refcnt, 1);
43	}
44	return sap;
45}
46
47/**
48 *	llc_add_sap - add sap to station list
49 *	@sap: Address of the sap
50 *
51 *	Adds a sap to the LLC's station sap list.
52 */
53static void llc_add_sap(struct llc_sap *sap)
54{
55	list_add_tail(&sap->node, &llc_sap_list);
56}
57
58/**
59 *	llc_del_sap - del sap from station list
60 *	@sap: Address of the sap
61 *
62 *	Removes a sap to the LLC's station sap list.
63 */
64static void llc_del_sap(struct llc_sap *sap)
65{
66	write_lock_bh(&llc_sap_list_lock);
67	list_del(&sap->node);
68	write_unlock_bh(&llc_sap_list_lock);
69}
70
71static struct llc_sap *__llc_sap_find(unsigned char sap_value)
72{
73	struct llc_sap* sap;
74
75	list_for_each_entry(sap, &llc_sap_list, node)
76		if (sap->laddr.lsap == sap_value)
77			goto out;
78	sap = NULL;
79out:
80	return sap;
81}
82
83/**
84 *	llc_sap_find - searchs a SAP in station
85 *	@sap_value: sap to be found
86 *
87 *	Searchs for a sap in the sap list of the LLC's station upon the sap ID.
88 *	If the sap is found it will be refcounted and the user will have to do
89 *	a llc_sap_put after use.
90 *	Returns the sap or %NULL if not found.
91 */
92struct llc_sap *llc_sap_find(unsigned char sap_value)
93{
94	struct llc_sap* sap;
95
96	read_lock_bh(&llc_sap_list_lock);
97	sap = __llc_sap_find(sap_value);
98	if (sap)
99		llc_sap_hold(sap);
100	read_unlock_bh(&llc_sap_list_lock);
101	return sap;
102}
103
104/**
105 *	llc_sap_open - open interface to the upper layers.
106 *	@lsap: SAP number.
107 *	@func: rcv func for datalink protos
108 *
109 *	Interface function to upper layer. Each one who wants to get a SAP
110 *	(for example NetBEUI) should call this function. Returns the opened
111 *	SAP for success, NULL for failure.
112 */
113struct llc_sap *llc_sap_open(unsigned char lsap,
114			     int (*func)(struct sk_buff *skb,
115					 struct net_device *dev,
116					 struct packet_type *pt,
117					 struct net_device *orig_dev))
118{
119	struct llc_sap *sap = NULL;
120
121	write_lock_bh(&llc_sap_list_lock);
122	if (__llc_sap_find(lsap)) /* SAP already exists */
123		goto out;
124	sap = llc_sap_alloc();
125	if (!sap)
126		goto out;
127	sap->laddr.lsap = lsap;
128	sap->rcv_func	= func;
129	llc_add_sap(sap);
130out:
131	write_unlock_bh(&llc_sap_list_lock);
132	return sap;
133}
134
135/**
136 *	llc_sap_close - close interface for upper layers.
137 *	@sap: SAP to be closed.
138 *
139 *	Close interface function to upper layer. Each one who wants to
140 *	close an open SAP (for example NetBEUI) should call this function.
141 * 	Removes this sap from the list of saps in the station and then
142 * 	frees the memory for this sap.
143 */
144void llc_sap_close(struct llc_sap *sap)
145{
146	WARN_ON(!hlist_empty(&sap->sk_list.list));
147	llc_del_sap(sap);
148	kfree(sap);
149}
150
151static struct packet_type llc_packet_type = {
152	.type = __constant_htons(ETH_P_802_2),
153	.func = llc_rcv,
154};
155
156static struct packet_type llc_tr_packet_type = {
157	.type = __constant_htons(ETH_P_TR_802_2),
158	.func = llc_rcv,
159};
160
161static int __init llc_init(void)
162{
163	struct net_device *dev;
164
165	dev = first_net_device();
166	if (dev != NULL)
167		dev = next_net_device(dev);
168
169	if (dev != NULL)
170		memcpy(llc_station_mac_sa, dev->dev_addr, ETH_ALEN);
171	else
172		memset(llc_station_mac_sa, 0, ETH_ALEN);
173	dev_add_pack(&llc_packet_type);
174	dev_add_pack(&llc_tr_packet_type);
175	return 0;
176}
177
178static void __exit llc_exit(void)
179{
180	dev_remove_pack(&llc_packet_type);
181	dev_remove_pack(&llc_tr_packet_type);
182}
183
184module_init(llc_init);
185module_exit(llc_exit);
186
187EXPORT_SYMBOL(llc_station_mac_sa);
188EXPORT_SYMBOL(llc_sap_list);
189EXPORT_SYMBOL(llc_sap_list_lock);
190EXPORT_SYMBOL(llc_sap_find);
191EXPORT_SYMBOL(llc_sap_open);
192EXPORT_SYMBOL(llc_sap_close);
193
194MODULE_LICENSE("GPL");
195MODULE_AUTHOR("Procom 1997, Jay Schullist 2001, Arnaldo C. Melo 2001-2003");
196MODULE_DESCRIPTION("LLC IEEE 802.2 core support");
197