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
25 LIST_HEAD(llc_sap_list);
26 static DEFINE_SPINLOCK(llc_sap_list_lock);
27
28 /**
29 * llc_sap_alloc - allocates and initializes sap.
30 *
31 * Allocates and initializes sap.
32 */
llc_sap_alloc(void)33 static 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 refcount_set(&sap->refcnt, 1);
45 }
46 return sap;
47 }
48
__llc_sap_find(unsigned char sap_value)49 static struct llc_sap *__llc_sap_find(unsigned char sap_value)
50 {
51 struct llc_sap *sap;
52
53 list_for_each_entry(sap, &llc_sap_list, node)
54 if (sap->laddr.lsap == sap_value)
55 goto out;
56 sap = NULL;
57 out:
58 return sap;
59 }
60
61 /**
62 * llc_sap_find - searchs a SAP in station
63 * @sap_value: sap to be found
64 *
65 * Searchs for a sap in the sap list of the LLC's station upon the sap ID.
66 * If the sap is found it will be refcounted and the user will have to do
67 * a llc_sap_put after use.
68 * Returns the sap or %NULL if not found.
69 */
llc_sap_find(unsigned char sap_value)70 struct llc_sap *llc_sap_find(unsigned char sap_value)
71 {
72 struct llc_sap *sap;
73
74 rcu_read_lock_bh();
75 sap = __llc_sap_find(sap_value);
76 if (!sap || !llc_sap_hold_safe(sap))
77 sap = NULL;
78 rcu_read_unlock_bh();
79 return sap;
80 }
81
82 /**
83 * llc_sap_open - open interface to the upper layers.
84 * @lsap: SAP number.
85 * @func: rcv func for datalink protos
86 *
87 * Interface function to upper layer. Each one who wants to get a SAP
88 * (for example NetBEUI) should call this function. Returns the opened
89 * SAP for success, NULL for failure.
90 */
llc_sap_open(unsigned char lsap,int (* func)(struct sk_buff * skb,struct net_device * dev,struct packet_type * pt,struct net_device * orig_dev))91 struct llc_sap *llc_sap_open(unsigned char lsap,
92 int (*func)(struct sk_buff *skb,
93 struct net_device *dev,
94 struct packet_type *pt,
95 struct net_device *orig_dev))
96 {
97 struct llc_sap *sap = NULL;
98
99 spin_lock_bh(&llc_sap_list_lock);
100 if (__llc_sap_find(lsap)) /* SAP already exists */
101 goto out;
102 sap = llc_sap_alloc();
103 if (!sap)
104 goto out;
105 sap->laddr.lsap = lsap;
106 sap->rcv_func = func;
107 list_add_tail_rcu(&sap->node, &llc_sap_list);
108 out:
109 spin_unlock_bh(&llc_sap_list_lock);
110 return sap;
111 }
112
113 /**
114 * llc_sap_close - close interface for upper layers.
115 * @sap: SAP to be closed.
116 *
117 * Close interface function to upper layer. Each one who wants to
118 * close an open SAP (for example NetBEUI) should call this function.
119 * Removes this sap from the list of saps in the station and then
120 * frees the memory for this sap.
121 */
llc_sap_close(struct llc_sap * sap)122 void llc_sap_close(struct llc_sap *sap)
123 {
124 WARN_ON(sap->sk_count);
125
126 spin_lock_bh(&llc_sap_list_lock);
127 list_del_rcu(&sap->node);
128 spin_unlock_bh(&llc_sap_list_lock);
129
130 kfree_rcu(sap, rcu);
131 }
132
133 static struct packet_type llc_packet_type __read_mostly = {
134 .type = cpu_to_be16(ETH_P_802_2),
135 .func = llc_rcv,
136 };
137
138 static struct packet_type llc_tr_packet_type __read_mostly = {
139 .type = cpu_to_be16(ETH_P_TR_802_2),
140 .func = llc_rcv,
141 };
142
llc_init(void)143 static int __init llc_init(void)
144 {
145 dev_add_pack(&llc_packet_type);
146 dev_add_pack(&llc_tr_packet_type);
147 return 0;
148 }
149
llc_exit(void)150 static void __exit llc_exit(void)
151 {
152 dev_remove_pack(&llc_packet_type);
153 dev_remove_pack(&llc_tr_packet_type);
154 }
155
156 module_init(llc_init);
157 module_exit(llc_exit);
158
159 EXPORT_SYMBOL(llc_sap_list);
160 EXPORT_SYMBOL(llc_sap_find);
161 EXPORT_SYMBOL(llc_sap_open);
162 EXPORT_SYMBOL(llc_sap_close);
163
164 MODULE_LICENSE("GPL");
165 MODULE_AUTHOR("Procom 1997, Jay Schullist 2001, Arnaldo C. Melo 2001-2003");
166 MODULE_DESCRIPTION("LLC IEEE 802.2 core support");
167
