net/llc/llc_core.c

   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         struct net_device *dev;
 164
 165         dev = first_net_device();
 166         if (dev != NULL)
 167                 dev = next_net_device(dev);
 168
 169         if (dev != NULL)
 170                 memcpy(llc_station_mac_sa, dev->dev_addr, ETH_ALEN);
 171         else
 172                 memset(llc_station_mac_sa, 0, ETH_ALEN);
 173         dev_add_pack(&llc_packet_type);
 174         dev_add_pack(&llc_tr_packet_type);
 175         return 0;
 176 }
 177
 178 static void __exit llc_exit(void)
 179 {
 180         dev_remove_pack(&llc_packet_type);
 181         dev_remove_pack(&llc_tr_packet_type);
 182 }
 183
 184 module_init(llc_init);
 185 module_exit(llc_exit);
 186
 187 EXPORT_SYMBOL(llc_station_mac_sa);
 188 EXPORT_SYMBOL(llc_sap_list);
 189 EXPORT_SYMBOL(llc_sap_list_lock);
 190 EXPORT_SYMBOL(llc_sap_find);
 191 EXPORT_SYMBOL(llc_sap_open);
 192 EXPORT_SYMBOL(llc_sap_close);
 193
 194 MODULE_LICENSE("GPL");
 195 MODULE_AUTHOR("Procom 1997, Jay Schullist 2001, Arnaldo C. Melo 2001-2003");
 196 MODULE_DESCRIPTION("LLC IEEE 802.2 core support");