xref: /openbmc/linux/net/llc/llc_core.c (revision 87c2ce3b)
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 
24 LIST_HEAD(llc_sap_list);
25 DEFINE_RWLOCK(llc_sap_list_lock);
26 
27 unsigned char llc_station_mac_sa[ETH_ALEN];
28 
29 /**
30  *	llc_sap_alloc - allocates and initializes sap.
31  *
32  *	Allocates and initializes sap.
33  */
34 static 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  */
54 static 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  */
65 static 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 
72 static struct 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;
80 out:
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  */
93 struct 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  */
114 struct 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);
132 out:
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  */
146 void 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 
153 static struct packet_type llc_packet_type = {
154 	.type = __constant_htons(ETH_P_802_2),
155 	.func = llc_rcv,
156 };
157 
158 static struct packet_type llc_tr_packet_type = {
159 	.type = __constant_htons(ETH_P_TR_802_2),
160 	.func = llc_rcv,
161 };
162 
163 static 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 
174 static void __exit llc_exit(void)
175 {
176 	dev_remove_pack(&llc_packet_type);
177 	dev_remove_pack(&llc_tr_packet_type);
178 }
179 
180 module_init(llc_init);
181 module_exit(llc_exit);
182 
183 EXPORT_SYMBOL(llc_station_mac_sa);
184 EXPORT_SYMBOL(llc_sap_list);
185 EXPORT_SYMBOL(llc_sap_list_lock);
186 EXPORT_SYMBOL(llc_sap_find);
187 EXPORT_SYMBOL(llc_sap_open);
188 EXPORT_SYMBOL(llc_sap_close);
189 
190 MODULE_LICENSE("GPL");
191 MODULE_AUTHOR("Procom 1997, Jay Schullist 2001, Arnaldo C. Melo 2001-2003");
192 MODULE_DESCRIPTION("LLC IEEE 802.2 core support");
193