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/net_namespace.h>
  23 #include <net/llc.h>
  24
  25 LIST_HEAD(llc_sap_list);
  26 DEFINE_RWLOCK(llc_sap_list_lock);
  27
  28 unsigned char llc_station_mac_sa[ETH_ALEN];
  29
  30 /**
  31  *      llc_sap_alloc - allocates and initializes sap.
  32  *
  33  *      Allocates and initializes sap.
  34  */
  35 static struct llc_sap *llc_sap_alloc(void)
  36 {
  37         struct llc_sap *sap = kzalloc(sizeof(*sap), GFP_ATOMIC);
  38
  39         if (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_add_sap(sap);
 131 out:
 132         write_unlock_bh(&llc_sap_list_lock);
 133         return sap;
 134 }
 135
 136 /**
 137  *      llc_sap_close - close interface for upper layers.
 138  *      @sap: SAP to be closed.
 139  *
 140  *      Close interface function to upper layer. Each one who wants to
 141  *      close an open SAP (for example NetBEUI) should call this function.
 142  *      Removes this sap from the list of saps in the station and then
 143  *      frees the memory for this sap.
 144  */
 145 void llc_sap_close(struct llc_sap *sap)
 146 {
 147         WARN_ON(!hlist_empty(&sap->sk_list.list));
 148         llc_del_sap(sap);
 149         kfree(sap);
 150 }
 151
 152 static struct packet_type llc_packet_type = {
 153         .type = __constant_htons(ETH_P_802_2),
 154         .func = llc_rcv,
 155 };
 156
 157 static struct packet_type llc_tr_packet_type = {
 158         .type = __constant_htons(ETH_P_TR_802_2),
 159         .func = llc_rcv,
 160 };
 161
 162 static int __init llc_init(void)
 163 {
 164         struct net_device *dev;
 165
 166         dev = first_net_device(&init_net);
 167         if (dev != NULL)
 168                 dev = next_net_device(dev);
 169
 170         if (dev != NULL)
 171                 memcpy(llc_station_mac_sa, dev->dev_addr, ETH_ALEN);
 172         else
 173                 memset(llc_station_mac_sa, 0, ETH_ALEN);
 174         dev_add_pack(&llc_packet_type);
 175         dev_add_pack(&llc_tr_packet_type);
 176         return 0;
 177 }
 178
 179 static void __exit llc_exit(void)
 180 {
 181         dev_remove_pack(&llc_packet_type);
 182         dev_remove_pack(&llc_tr_packet_type);
 183 }
 184
 185 module_init(llc_init);
 186 module_exit(llc_exit);
 187
 188 EXPORT_SYMBOL(llc_station_mac_sa);
 189 EXPORT_SYMBOL(llc_sap_list);
 190 EXPORT_SYMBOL(llc_sap_list_lock);
 191 EXPORT_SYMBOL(llc_sap_find);
 192 EXPORT_SYMBOL(llc_sap_open);
 193 EXPORT_SYMBOL(llc_sap_close);
 194
 195 MODULE_LICENSE("GPL");
 196 MODULE_AUTHOR("Procom 1997, Jay Schullist 2001, Arnaldo C. Melo 2001-2003");
 197 MODULE_DESCRIPTION("LLC IEEE 802.2 core support");