llc_core.c revision f2ccd8fa06c8e302116e71df372f5c1f83432e03 
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	}
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	write_lock_bh(&llc_sap_list_lock);
56	list_add_tail(&sap->node, &llc_sap_list);
57	write_unlock_bh(&llc_sap_list_lock);
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
73/**
74 *	llc_sap_find - searchs a SAP in station
75 *	@sap_value: sap to be found
76 *
77 *	Searchs for a sap in the sap list of the LLC's station upon the sap ID.
78 *	Returns the sap or %NULL if not found.
79 */
80struct llc_sap *llc_sap_find(unsigned char sap_value)
81{
82	struct llc_sap* sap;
83
84	read_lock_bh(&llc_sap_list_lock);
85	list_for_each_entry(sap, &llc_sap_list, node)
86		if (sap->laddr.lsap == sap_value)
87			goto out;
88	sap = NULL;
89out:
90	read_unlock_bh(&llc_sap_list_lock);
91	return sap;
92}
93
94/**
95 *	llc_sap_open - open interface to the upper layers.
96 *	@lsap: SAP number.
97 *	@func: rcv func for datalink protos
98 *
99 *	Interface function to upper layer. Each one who wants to get a SAP
100 *	(for example NetBEUI) should call this function. Returns the opened
101 *	SAP for success, NULL for failure.
102 */
103struct llc_sap *llc_sap_open(unsigned char lsap,
104			     int (*func)(struct sk_buff *skb,
105					 struct net_device *dev,
106					 struct packet_type *pt,
107					 struct net_device *orig_dev))
108{
109	struct llc_sap *sap = llc_sap_find(lsap);
110
111	if (sap) { /* SAP already exists */
112		sap = NULL;
113		goto out;
114	}
115	sap = llc_sap_alloc();
116	if (!sap)
117		goto out;
118	sap->laddr.lsap = lsap;
119	sap->rcv_func	= func;
120	llc_add_sap(sap);
121out:
122	return sap;
123}
124
125/**
126 *	llc_sap_close - close interface for upper layers.
127 *	@sap: SAP to be closed.
128 *
129 *	Close interface function to upper layer. Each one who wants to
130 *	close an open SAP (for example NetBEUI) should call this function.
131 * 	Removes this sap from the list of saps in the station and then
132 * 	frees the memory for this sap.
133 */
134void llc_sap_close(struct llc_sap *sap)
135{
136	WARN_ON(!hlist_empty(&sap->sk_list.list));
137	llc_del_sap(sap);
138	kfree(sap);
139}
140
141static struct packet_type llc_packet_type = {
142	.type = __constant_htons(ETH_P_802_2),
143	.func = llc_rcv,
144};
145
146static struct packet_type llc_tr_packet_type = {
147	.type = __constant_htons(ETH_P_TR_802_2),
148	.func = llc_rcv,
149};
150
151static int __init llc_init(void)
152{
153	if (dev_base->next)
154		memcpy(llc_station_mac_sa, dev_base->next->dev_addr, ETH_ALEN);
155	else
156		memset(llc_station_mac_sa, 0, ETH_ALEN);
157	dev_add_pack(&llc_packet_type);
158	dev_add_pack(&llc_tr_packet_type);
159	return 0;
160}
161
162static void __exit llc_exit(void)
163{
164	dev_remove_pack(&llc_packet_type);
165	dev_remove_pack(&llc_tr_packet_type);
166}
167
168module_init(llc_init);
169module_exit(llc_exit);
170
171EXPORT_SYMBOL(llc_station_mac_sa);
172EXPORT_SYMBOL(llc_sap_list);
173EXPORT_SYMBOL(llc_sap_list_lock);
174EXPORT_SYMBOL(llc_sap_find);
175EXPORT_SYMBOL(llc_sap_open);
176EXPORT_SYMBOL(llc_sap_close);
177
178MODULE_LICENSE("GPL");
179MODULE_AUTHOR("Procom 1997, Jay Schullist 2001, Arnaldo C. Melo 2001-2003");
180MODULE_DESCRIPTION("LLC IEEE 802.2 core support");
181