llc_core.c revision 6e2144b76840be09924de1626e2dcd7b315f75b3 
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 = kmalloc(sizeof(*sap), GFP_ATOMIC);
37
38	if (sap) {
39		memset(sap, 0, sizeof(*sap));
40		sap->state = LLC_SAP_STATE_ACTIVE;
41		memcpy(sap->laddr.mac, llc_station_mac_sa, ETH_ALEN);
42		rwlock_init(&sap->sk_list.lock);
43		atomic_set(&sap->refcnt, 1);
44	}
45	return sap;
46}
47
48/**
49 *	llc_add_sap - add sap to station list
50 *	@sap: Address of the sap
51 *
52 *	Adds a sap to the LLC's station sap list.
53 */
54static void llc_add_sap(struct llc_sap *sap)
55{
56	list_add_tail(&sap->node, &llc_sap_list);
57}
58
59/**
60 *	llc_del_sap - del sap from station list
61 *	@sap: Address of the sap
62 *
63 *	Removes a sap to the LLC's station sap list.
64 */
65static void llc_del_sap(struct llc_sap *sap)
66{
67	write_lock_bh(&llc_sap_list_lock);
68	list_del(&sap->node);
69	write_unlock_bh(&llc_sap_list_lock);
70}
71
72struct llc_sap *__llc_sap_find(unsigned char sap_value)
73{
74	struct llc_sap* sap;
75
76	list_for_each_entry(sap, &llc_sap_list, node)
77		if (sap->laddr.lsap == sap_value)
78			goto out;
79	sap = NULL;
80out:
81	return sap;
82}
83
84/**
85 *	llc_sap_find - searchs a SAP in station
86 *	@sap_value: sap to be found
87 *
88 *	Searchs for a sap in the sap list of the LLC's station upon the sap ID.
89 *	If the sap is found it will be refcounted and the user will have to do
90 *	a llc_sap_put after use.
91 *	Returns the sap or %NULL if not found.
92 */
93struct llc_sap *llc_sap_find(unsigned char sap_value)
94{
95	struct llc_sap* sap;
96
97	read_lock_bh(&llc_sap_list_lock);
98	sap = __llc_sap_find(sap_value);
99	if (sap)
100		llc_sap_hold(sap);
101	read_unlock_bh(&llc_sap_list_lock);
102	return sap;
103}
104
105/**
106 *	llc_sap_open - open interface to the upper layers.
107 *	@lsap: SAP number.
108 *	@func: rcv func for datalink protos
109 *
110 *	Interface function to upper layer. Each one who wants to get a SAP
111 *	(for example NetBEUI) should call this function. Returns the opened
112 *	SAP for success, NULL for failure.
113 */
114struct llc_sap *llc_sap_open(unsigned char lsap,
115			     int (*func)(struct sk_buff *skb,
116					 struct net_device *dev,
117					 struct packet_type *pt,
118					 struct net_device *orig_dev))
119{
120	struct llc_sap *sap = NULL;
121
122	write_lock_bh(&llc_sap_list_lock);
123	if (__llc_sap_find(lsap)) /* SAP already exists */
124		goto out;
125	sap = llc_sap_alloc();
126	if (!sap)
127		goto out;
128	sap->laddr.lsap = lsap;
129	sap->rcv_func	= func;
130	llc_sap_hold(sap);
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(!hlist_empty(&sap->sk_list.list));
149	llc_del_sap(sap);
150	kfree(sap);
151}
152
153static struct packet_type llc_packet_type = {
154	.type = __constant_htons(ETH_P_802_2),
155	.func = llc_rcv,
156};
157
158static struct packet_type llc_tr_packet_type = {
159	.type = __constant_htons(ETH_P_TR_802_2),
160	.func = llc_rcv,
161};
162
163static int __init llc_init(void)
164{
165	if (dev_base->next)
166		memcpy(llc_station_mac_sa, dev_base->next->dev_addr, ETH_ALEN);
167	else
168		memset(llc_station_mac_sa, 0, ETH_ALEN);
169	dev_add_pack(&llc_packet_type);
170	dev_add_pack(&llc_tr_packet_type);
171	return 0;
172}
173
174static void __exit llc_exit(void)
175{
176	dev_remove_pack(&llc_packet_type);
177	dev_remove_pack(&llc_tr_packet_type);
178}
179
180module_init(llc_init);
181module_exit(llc_exit);
182
183EXPORT_SYMBOL(llc_station_mac_sa);
184EXPORT_SYMBOL(llc_sap_list);
185EXPORT_SYMBOL(llc_sap_list_lock);
186EXPORT_SYMBOL(llc_sap_find);
187EXPORT_SYMBOL(llc_sap_open);
188EXPORT_SYMBOL(llc_sap_close);
189
190MODULE_LICENSE("GPL");
191MODULE_AUTHOR("Procom 1997, Jay Schullist 2001, Arnaldo C. Melo 2001-2003");
192MODULE_DESCRIPTION("LLC IEEE 802.2 core support");
193