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 = kzalloc(sizeof(*sap), GFP_ATOMIC); 37 38 if (sap) { 39 sap->state = LLC_SAP_STATE_ACTIVE; 40 memcpy(sap->laddr.mac, llc_station_mac_sa, ETH_ALEN); 41 rwlock_init(&sap->sk_list.lock); 42 atomic_set(&sap->refcnt, 1); 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 */ 53 static void llc_add_sap(struct llc_sap *sap) 54 { 55 list_add_tail(&sap->node, &llc_sap_list); 56 } 57 58 /** 59 * llc_del_sap - del sap from station list 60 * @sap: Address of the sap 61 * 62 * Removes a sap to the LLC's station sap list. 63 */ 64 static void llc_del_sap(struct llc_sap *sap) 65 { 66 write_lock_bh(&llc_sap_list_lock); 67 list_del(&sap->node); 68 write_unlock_bh(&llc_sap_list_lock); 69 } 70 71 static struct llc_sap *__llc_sap_find(unsigned char sap_value) 72 { 73 struct llc_sap* sap; 74 75 list_for_each_entry(sap, &llc_sap_list, node) 76 if (sap->laddr.lsap == sap_value) 77 goto out; 78 sap = NULL; 79 out: 80 return sap; 81 } 82 83 /** 84 * llc_sap_find - searchs a SAP in station 85 * @sap_value: sap to be found 86 * 87 * Searchs for a sap in the sap list of the LLC's station upon the sap ID. 88 * If the sap is found it will be refcounted and the user will have to do 89 * a llc_sap_put after use. 90 * Returns the sap or %NULL if not found. 91 */ 92 struct llc_sap *llc_sap_find(unsigned char sap_value) 93 { 94 struct llc_sap* sap; 95 96 read_lock_bh(&llc_sap_list_lock); 97 sap = __llc_sap_find(sap_value); 98 if (sap) 99 llc_sap_hold(sap); 100 read_unlock_bh(&llc_sap_list_lock); 101 return sap; 102 } 103 104 /** 105 * llc_sap_open - open interface to the upper layers. 106 * @lsap: SAP number. 107 * @func: rcv func for datalink protos 108 * 109 * Interface function to upper layer. Each one who wants to get a SAP 110 * (for example NetBEUI) should call this function. Returns the opened 111 * SAP for success, NULL for failure. 112 */ 113 struct llc_sap *llc_sap_open(unsigned char lsap, 114 int (*func)(struct sk_buff *skb, 115 struct net_device *dev, 116 struct packet_type *pt, 117 struct net_device *orig_dev)) 118 { 119 struct llc_sap *sap = NULL; 120 121 write_lock_bh(&llc_sap_list_lock); 122 if (__llc_sap_find(lsap)) /* SAP already exists */ 123 goto out; 124 sap = llc_sap_alloc(); 125 if (!sap) 126 goto out; 127 sap->laddr.lsap = lsap; 128 sap->rcv_func = func; 129 llc_add_sap(sap); 130 out: 131 write_unlock_bh(&llc_sap_list_lock); 132 return sap; 133 } 134 135 /** 136 * llc_sap_close - close interface for upper layers. 137 * @sap: SAP to be closed. 138 * 139 * Close interface function to upper layer. Each one who wants to 140 * close an open SAP (for example NetBEUI) should call this function. 141 * Removes this sap from the list of saps in the station and then 142 * frees the memory for this sap. 143 */ 144 void llc_sap_close(struct llc_sap *sap) 145 { 146 WARN_ON(!hlist_empty(&sap->sk_list.list)); 147 llc_del_sap(sap); 148 kfree(sap); 149 } 150 151 static struct packet_type llc_packet_type = { 152 .type = __constant_htons(ETH_P_802_2), 153 .func = llc_rcv, 154 }; 155 156 static struct packet_type llc_tr_packet_type = { 157 .type = __constant_htons(ETH_P_TR_802_2), 158 .func = llc_rcv, 159 }; 160 161 static int __init llc_init(void) 162 { 163 if (dev_base->next) 164 memcpy(llc_station_mac_sa, dev_base->next->dev_addr, ETH_ALEN); 165 else 166 memset(llc_station_mac_sa, 0, ETH_ALEN); 167 dev_add_pack(&llc_packet_type); 168 dev_add_pack(&llc_tr_packet_type); 169 return 0; 170 } 171 172 static void __exit llc_exit(void) 173 { 174 dev_remove_pack(&llc_packet_type); 175 dev_remove_pack(&llc_tr_packet_type); 176 } 177 178 module_init(llc_init); 179 module_exit(llc_exit); 180 181 EXPORT_SYMBOL(llc_station_mac_sa); 182 EXPORT_SYMBOL(llc_sap_list); 183 EXPORT_SYMBOL(llc_sap_list_lock); 184 EXPORT_SYMBOL(llc_sap_find); 185 EXPORT_SYMBOL(llc_sap_open); 186 EXPORT_SYMBOL(llc_sap_close); 187 188 MODULE_LICENSE("GPL"); 189 MODULE_AUTHOR("Procom 1997, Jay Schullist 2001, Arnaldo C. Melo 2001-2003"); 190 MODULE_DESCRIPTION("LLC IEEE 802.2 core support"); 191