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 */ 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 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 - searches a SAP in station 63 * @sap_value: sap to be found 64 * 65 * Searches 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 */ 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 */ 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 */ 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 int __init llc_init(void) 139 { 140 dev_add_pack(&llc_packet_type); 141 return 0; 142 } 143 144 static void __exit llc_exit(void) 145 { 146 dev_remove_pack(&llc_packet_type); 147 } 148 149 module_init(llc_init); 150 module_exit(llc_exit); 151 152 EXPORT_SYMBOL(llc_sap_list); 153 EXPORT_SYMBOL(llc_sap_find); 154 EXPORT_SYMBOL(llc_sap_open); 155 EXPORT_SYMBOL(llc_sap_close); 156 157 MODULE_LICENSE("GPL"); 158 MODULE_AUTHOR("Procom 1997, Jay Schullist 2001, Arnaldo C. Melo 2001-2003"); 159 MODULE_DESCRIPTION("LLC IEEE 802.2 core support"); 160