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