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 DEFINE_RWLOCK(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 37 if (sap) { 38 /* sap->laddr.mac - leave as a null, it's filled by bind */ 39 sap->state = LLC_SAP_STATE_ACTIVE; 40 rwlock_init(&sap->sk_list.lock); 41 atomic_set(&sap->refcnt, 1); 42 } 43 return sap; 44 } 45 46 /** 47 * llc_add_sap - add sap to station list 48 * @sap: Address of the sap 49 * 50 * Adds a sap to the LLC's station sap list. 51 */ 52 static void llc_add_sap(struct llc_sap *sap) 53 { 54 list_add_tail(&sap->node, &llc_sap_list); 55 } 56 57 /** 58 * llc_del_sap - del sap from station list 59 * @sap: Address of the sap 60 * 61 * Removes a sap to the LLC's station sap list. 62 */ 63 static void llc_del_sap(struct llc_sap *sap) 64 { 65 write_lock_bh(&llc_sap_list_lock); 66 list_del(&sap->node); 67 write_unlock_bh(&llc_sap_list_lock); 68 } 69 70 static struct llc_sap *__llc_sap_find(unsigned char sap_value) 71 { 72 struct llc_sap* sap; 73 74 list_for_each_entry(sap, &llc_sap_list, node) 75 if (sap->laddr.lsap == sap_value) 76 goto out; 77 sap = NULL; 78 out: 79 return sap; 80 } 81 82 /** 83 * llc_sap_find - searchs a SAP in station 84 * @sap_value: sap to be found 85 * 86 * Searchs for a sap in the sap list of the LLC's station upon the sap ID. 87 * If the sap is found it will be refcounted and the user will have to do 88 * a llc_sap_put after use. 89 * Returns the sap or %NULL if not found. 90 */ 91 struct llc_sap *llc_sap_find(unsigned char sap_value) 92 { 93 struct llc_sap* sap; 94 95 read_lock_bh(&llc_sap_list_lock); 96 sap = __llc_sap_find(sap_value); 97 if (sap) 98 llc_sap_hold(sap); 99 read_unlock_bh(&llc_sap_list_lock); 100 return sap; 101 } 102 103 /** 104 * llc_sap_open - open interface to the upper layers. 105 * @lsap: SAP number. 106 * @func: rcv func for datalink protos 107 * 108 * Interface function to upper layer. Each one who wants to get a SAP 109 * (for example NetBEUI) should call this function. Returns the opened 110 * SAP for success, NULL for failure. 111 */ 112 struct llc_sap *llc_sap_open(unsigned char lsap, 113 int (*func)(struct sk_buff *skb, 114 struct net_device *dev, 115 struct packet_type *pt, 116 struct net_device *orig_dev)) 117 { 118 struct llc_sap *sap = NULL; 119 120 write_lock_bh(&llc_sap_list_lock); 121 if (__llc_sap_find(lsap)) /* SAP already exists */ 122 goto out; 123 sap = llc_sap_alloc(); 124 if (!sap) 125 goto out; 126 sap->laddr.lsap = lsap; 127 sap->rcv_func = func; 128 llc_add_sap(sap); 129 out: 130 write_unlock_bh(&llc_sap_list_lock); 131 return sap; 132 } 133 134 /** 135 * llc_sap_close - close interface for upper layers. 136 * @sap: SAP to be closed. 137 * 138 * Close interface function to upper layer. Each one who wants to 139 * close an open SAP (for example NetBEUI) should call this function. 140 * Removes this sap from the list of saps in the station and then 141 * frees the memory for this sap. 142 */ 143 void llc_sap_close(struct llc_sap *sap) 144 { 145 WARN_ON(!hlist_empty(&sap->sk_list.list)); 146 llc_del_sap(sap); 147 kfree(sap); 148 } 149 150 static struct packet_type llc_packet_type = { 151 .type = __constant_htons(ETH_P_802_2), 152 .func = llc_rcv, 153 }; 154 155 static struct packet_type llc_tr_packet_type = { 156 .type = __constant_htons(ETH_P_TR_802_2), 157 .func = llc_rcv, 158 }; 159 160 static int __init llc_init(void) 161 { 162 struct net_device *dev; 163 164 dev = first_net_device(&init_net); 165 if (dev != NULL) 166 dev = next_net_device(dev); 167 168 dev_add_pack(&llc_packet_type); 169 dev_add_pack(&llc_tr_packet_type); 170 return 0; 171 } 172 173 static void __exit llc_exit(void) 174 { 175 dev_remove_pack(&llc_packet_type); 176 dev_remove_pack(&llc_tr_packet_type); 177 } 178 179 module_init(llc_init); 180 module_exit(llc_exit); 181 182 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