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