net/ax25/ax25_iface.c

   1 /*
   2  * This program is free software; you can redistribute it and/or modify
   3  * it under the terms of the GNU General Public License as published by
   4  * the Free Software Foundation; either version 2 of the License, or
   5  * (at your option) any later version.
   6  *
   7  * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
   8  */
   9 #include <linux/errno.h>
  10 #include <linux/types.h>
  11 #include <linux/socket.h>
  12 #include <linux/in.h>
  13 #include <linux/kernel.h>
  14 #include <linux/module.h>
  15 #include <linux/spinlock.h>
  16 #include <linux/timer.h>
  17 #include <linux/string.h>
  18 #include <linux/sockios.h>
  19 #include <linux/net.h>
  20 #include <linux/slab.h>
  21 #include <net/ax25.h>
  22 #include <linux/inet.h>
  23 #include <linux/netdevice.h>
  24 #include <linux/skbuff.h>
  25 #include <net/sock.h>
  26 #include <asm/uaccess.h>
  27 #include <asm/system.h>
  28 #include <linux/fcntl.h>
  29 #include <linux/mm.h>
  30 #include <linux/interrupt.h>
  31
  32 static struct ax25_protocol *protocol_list;
  33 static DEFINE_RWLOCK(protocol_list_lock);
  34
  35 static HLIST_HEAD(ax25_linkfail_list);
  36 static DEFINE_SPINLOCK(linkfail_lock);
  37
  38 static struct listen_struct {
  39         struct listen_struct *next;
  40         ax25_address  callsign;
  41         struct net_device *dev;
  42 } *listen_list = NULL;
  43 static DEFINE_SPINLOCK(listen_lock);
  44
  45 /*
  46  * Do not register the internal protocols AX25_P_TEXT, AX25_P_SEGMENT,
  47  * AX25_P_IP or AX25_P_ARP ...
  48  */
  49 void ax25_register_pid(struct ax25_protocol *ap)
  50 {
  51         write_lock_bh(&protocol_list_lock);
  52         ap->next = protocol_list;
  53         protocol_list = ap;
  54         write_unlock_bh(&protocol_list_lock);
  55 }
  56
  57 EXPORT_SYMBOL_GPL(ax25_register_pid);
  58
  59 void ax25_protocol_release(unsigned int pid)
  60 {
  61         struct ax25_protocol *s, *protocol;
  62
  63         write_lock_bh(&protocol_list_lock);
  64         protocol = protocol_list;
  65         if (protocol == NULL)
  66                 goto out;
  67
  68         if (protocol->pid == pid) {
  69                 protocol_list = protocol->next;
  70                 goto out;
  71         }
  72
  73         while (protocol != NULL && protocol->next != NULL) {
  74                 if (protocol->next->pid == pid) {
  75                         s = protocol->next;
  76                         protocol->next = protocol->next->next;
  77                         goto out;
  78                 }
  79
  80                 protocol = protocol->next;
  81         }
  82 out:
  83         write_unlock_bh(&protocol_list_lock);
  84 }
  85
  86 EXPORT_SYMBOL(ax25_protocol_release);
  87
  88 void ax25_linkfail_register(struct ax25_linkfail *lf)
  89 {
  90         spin_lock_bh(&linkfail_lock);
  91         hlist_add_head(&lf->lf_node, &ax25_linkfail_list);
  92         spin_unlock_bh(&linkfail_lock);
  93 }
  94
  95 EXPORT_SYMBOL(ax25_linkfail_register);
  96
  97 void ax25_linkfail_release(struct ax25_linkfail *lf)
  98 {
  99         spin_lock_bh(&linkfail_lock);
 100         hlist_del_init(&lf->lf_node);
 101         spin_unlock_bh(&linkfail_lock);
 102 }
 103
 104 EXPORT_SYMBOL(ax25_linkfail_release);
 105
 106 int ax25_listen_register(ax25_address *callsign, struct net_device *dev)
 107 {
 108         struct listen_struct *listen;
 109
 110         if (ax25_listen_mine(callsign, dev))
 111                 return 0;
 112
 113         if ((listen = kmalloc(sizeof(*listen), GFP_ATOMIC)) == NULL)
 114                 return -ENOMEM;
 115
 116         listen->callsign = *callsign;
 117         listen->dev      = dev;
 118
 119         spin_lock_bh(&listen_lock);
 120         listen->next = listen_list;
 121         listen_list  = listen;
 122         spin_unlock_bh(&listen_lock);
 123
 124         return 0;
 125 }
 126
 127 EXPORT_SYMBOL(ax25_listen_register);
 128
 129 void ax25_listen_release(ax25_address *callsign, struct net_device *dev)
 130 {
 131         struct listen_struct *s, *listen;
 132
 133         spin_lock_bh(&listen_lock);
 134         listen = listen_list;
 135         if (listen == NULL) {
 136                 spin_unlock_bh(&listen_lock);
 137                 return;
 138         }
 139
 140         if (ax25cmp(&listen->callsign, callsign) == 0 && listen->dev == dev) {
 141                 listen_list = listen->next;
 142                 spin_unlock_bh(&listen_lock);
 143                 kfree(listen);
 144                 return;
 145         }
 146
 147         while (listen != NULL && listen->next != NULL) {
 148                 if (ax25cmp(&listen->next->callsign, callsign) == 0 && listen->next->dev == dev) {
 149                         s = listen->next;
 150                         listen->next = listen->next->next;
 151                         spin_unlock_bh(&listen_lock);
 152                         kfree(s);
 153                         return;
 154                 }
 155
 156                 listen = listen->next;
 157         }
 158         spin_unlock_bh(&listen_lock);
 159 }
 160
 161 EXPORT_SYMBOL(ax25_listen_release);
 162
 163 int (*ax25_protocol_function(unsigned int pid))(struct sk_buff *, ax25_cb *)
 164 {
 165         int (*res)(struct sk_buff *, ax25_cb *) = NULL;
 166         struct ax25_protocol *protocol;
 167
 168         read_lock(&protocol_list_lock);
 169         for (protocol = protocol_list; protocol != NULL; protocol = protocol->next)
 170                 if (protocol->pid == pid) {
 171                         res = protocol->func;
 172                         break;
 173                 }
 174         read_unlock(&protocol_list_lock);
 175
 176         return res;
 177 }
 178
 179 int ax25_listen_mine(ax25_address *callsign, struct net_device *dev)
 180 {
 181         struct listen_struct *listen;
 182
 183         spin_lock_bh(&listen_lock);
 184         for (listen = listen_list; listen != NULL; listen = listen->next)
 185                 if (ax25cmp(&listen->callsign, callsign) == 0 &&
 186                     (listen->dev == dev || listen->dev == NULL)) {
 187                         spin_unlock_bh(&listen_lock);
 188                         return 1;
 189         }
 190         spin_unlock_bh(&listen_lock);
 191
 192         return 0;
 193 }
 194
 195 void ax25_link_failed(ax25_cb *ax25, int reason)
 196 {
 197         struct ax25_linkfail *lf;
 198         struct hlist_node *node;
 199
 200         spin_lock_bh(&linkfail_lock);
 201         hlist_for_each_entry(lf, node, &ax25_linkfail_list, lf_node)
 202                 lf->func(ax25, reason);
 203         spin_unlock_bh(&linkfail_lock);
 204 }
 205
 206 int ax25_protocol_is_registered(unsigned int pid)
 207 {
 208         struct ax25_protocol *protocol;
 209         int res = 0;
 210
 211         read_lock_bh(&protocol_list_lock);
 212         for (protocol = protocol_list; protocol != NULL; protocol = protocol->next)
 213                 if (protocol->pid == pid) {
 214                         res = 1;
 215                         break;
 216                 }
 217         read_unlock_bh(&protocol_list_lock);
 218
 219         return res;
 220 }