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/sched.h>
  16 #include <linux/spinlock.h>
  17 #include <linux/timer.h>
  18 #include <linux/string.h>
  19 #include <linux/sockios.h>
  20 #include <linux/net.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 protocol_struct {
  33         struct protocol_struct *next;
  34         unsigned int pid;
  35         int (*func)(struct sk_buff *, ax25_cb *);
  36 } *protocol_list = NULL;
  37 static DEFINE_RWLOCK(protocol_list_lock);
  38
  39 static struct linkfail_struct {
  40         struct linkfail_struct *next;
  41         void (*func)(ax25_cb *, int);
  42 } *linkfail_list = NULL;
  43 static DEFINE_SPINLOCK(linkfail_lock);
  44
  45 static struct listen_struct {
  46         struct listen_struct *next;
  47         ax25_address  callsign;
  48         struct net_device *dev;
  49 } *listen_list = NULL;
  50 static DEFINE_SPINLOCK(listen_lock);
  51
  52 int ax25_protocol_register(unsigned int pid,
  53         int (*func)(struct sk_buff *, ax25_cb *))
  54 {
  55         struct protocol_struct *protocol;
  56
  57         if (pid == AX25_P_TEXT || pid == AX25_P_SEGMENT)
  58                 return 0;
  59 #ifdef CONFIG_INET
  60         if (pid == AX25_P_IP || pid == AX25_P_ARP)
  61                 return 0;
  62 #endif
  63         if ((protocol = kmalloc(sizeof(*protocol), GFP_ATOMIC)) == NULL)
  64                 return 0;
  65
  66         protocol->pid  = pid;
  67         protocol->func = func;
  68
  69         write_lock(&protocol_list_lock);
  70         protocol->next = protocol_list;
  71         protocol_list  = protocol;
  72         write_unlock(&protocol_list_lock);
  73
  74         return 1;
  75 }
  76
  77 EXPORT_SYMBOL(ax25_protocol_register);
  78
  79 void ax25_protocol_release(unsigned int pid)
  80 {
  81         struct protocol_struct *s, *protocol;
  82
  83         write_lock(&protocol_list_lock);
  84         protocol = protocol_list;
  85         if (protocol == NULL) {
  86                 write_unlock(&protocol_list_lock);
  87                 return;
  88         }
  89
  90         if (protocol->pid == pid) {
  91                 protocol_list = protocol->next;
  92                 write_unlock(&protocol_list_lock);
  93                 kfree(protocol);
  94                 return;
  95         }
  96
  97         while (protocol != NULL && protocol->next != NULL) {
  98                 if (protocol->next->pid == pid) {
  99                         s = protocol->next;
 100                         protocol->next = protocol->next->next;
 101                         write_unlock(&protocol_list_lock);
 102                         kfree(s);
 103                         return;
 104                 }
 105
 106                 protocol = protocol->next;
 107         }
 108         write_unlock(&protocol_list_lock);
 109 }
 110
 111 EXPORT_SYMBOL(ax25_protocol_release);
 112
 113 int ax25_linkfail_register(void (*func)(ax25_cb *, int))
 114 {
 115         struct linkfail_struct *linkfail;
 116
 117         if ((linkfail = kmalloc(sizeof(*linkfail), GFP_ATOMIC)) == NULL)
 118                 return 0;
 119
 120         linkfail->func = func;
 121
 122         spin_lock_bh(&linkfail_lock);
 123         linkfail->next = linkfail_list;
 124         linkfail_list  = linkfail;
 125         spin_unlock_bh(&linkfail_lock);
 126
 127         return 1;
 128 }
 129
 130 EXPORT_SYMBOL(ax25_linkfail_register);
 131
 132 void ax25_linkfail_release(void (*func)(ax25_cb *, int))
 133 {
 134         struct linkfail_struct *s, *linkfail;
 135
 136         spin_lock_bh(&linkfail_lock);
 137         linkfail = linkfail_list;
 138         if (linkfail == NULL) {
 139                 spin_unlock_bh(&linkfail_lock);
 140                 return;
 141         }
 142
 143         if (linkfail->func == func) {
 144                 linkfail_list = linkfail->next;
 145                 spin_unlock_bh(&linkfail_lock);
 146                 kfree(linkfail);
 147                 return;
 148         }
 149
 150         while (linkfail != NULL && linkfail->next != NULL) {
 151                 if (linkfail->next->func == func) {
 152                         s = linkfail->next;
 153                         linkfail->next = linkfail->next->next;
 154                         spin_unlock_bh(&linkfail_lock);
 155                         kfree(s);
 156                         return;
 157                 }
 158
 159                 linkfail = linkfail->next;
 160         }
 161         spin_unlock_bh(&linkfail_lock);
 162 }
 163
 164 EXPORT_SYMBOL(ax25_linkfail_release);
 165
 166 int ax25_listen_register(ax25_address *callsign, struct net_device *dev)
 167 {
 168         struct listen_struct *listen;
 169
 170         if (ax25_listen_mine(callsign, dev))
 171                 return 0;
 172
 173         if ((listen = kmalloc(sizeof(*listen), GFP_ATOMIC)) == NULL)
 174                 return 0;
 175
 176         listen->callsign = *callsign;
 177         listen->dev      = dev;
 178
 179         spin_lock_bh(&listen_lock);
 180         listen->next = listen_list;
 181         listen_list  = listen;
 182         spin_unlock_bh(&listen_lock);
 183
 184         return 1;
 185 }
 186
 187 EXPORT_SYMBOL(ax25_listen_register);
 188
 189 void ax25_listen_release(ax25_address *callsign, struct net_device *dev)
 190 {
 191         struct listen_struct *s, *listen;
 192
 193         spin_lock_bh(&listen_lock);
 194         listen = listen_list;
 195         if (listen == NULL) {
 196                 spin_unlock_bh(&listen_lock);
 197                 return;
 198         }
 199
 200         if (ax25cmp(&listen->callsign, callsign) == 0 && listen->dev == dev) {
 201                 listen_list = listen->next;
 202                 spin_unlock_bh(&listen_lock);
 203                 kfree(listen);
 204                 return;
 205         }
 206
 207         while (listen != NULL && listen->next != NULL) {
 208                 if (ax25cmp(&listen->next->callsign, callsign) == 0 && listen->next->dev == dev) {
 209                         s = listen->next;
 210                         listen->next = listen->next->next;
 211                         spin_unlock_bh(&listen_lock);
 212                         kfree(s);
 213                         return;
 214                 }
 215
 216                 listen = listen->next;
 217         }
 218         spin_unlock_bh(&listen_lock);
 219 }
 220
 221 EXPORT_SYMBOL(ax25_listen_release);
 222
 223 int (*ax25_protocol_function(unsigned int pid))(struct sk_buff *, ax25_cb *)
 224 {
 225         int (*res)(struct sk_buff *, ax25_cb *) = NULL;
 226         struct protocol_struct *protocol;
 227
 228         read_lock(&protocol_list_lock);
 229         for (protocol = protocol_list; protocol != NULL; protocol = protocol->next)
 230                 if (protocol->pid == pid) {
 231                         res = protocol->func;
 232                         break;
 233                 }
 234         read_unlock(&protocol_list_lock);
 235
 236         return res;
 237 }
 238
 239 int ax25_listen_mine(ax25_address *callsign, struct net_device *dev)
 240 {
 241         struct listen_struct *listen;
 242
 243         spin_lock_bh(&listen_lock);
 244         for (listen = listen_list; listen != NULL; listen = listen->next)
 245                 if (ax25cmp(&listen->callsign, callsign) == 0 && (listen->dev == dev || listen->dev == NULL)) {
 246                         spin_unlock_bh(&listen_lock);
 247                         return 1;
 248         }
 249         spin_unlock_bh(&listen_lock);
 250
 251         return 0;
 252 }
 253
 254 void ax25_link_failed(ax25_cb *ax25, int reason)
 255 {
 256         struct linkfail_struct *linkfail;
 257
 258         spin_lock_bh(&linkfail_lock);
 259         for (linkfail = linkfail_list; linkfail != NULL; linkfail = linkfail->next)
 260                 (linkfail->func)(ax25, reason);
 261         spin_unlock_bh(&linkfail_lock);
 262 }
 263
 264 int ax25_protocol_is_registered(unsigned int pid)
 265 {
 266         struct protocol_struct *protocol;
 267         int res = 0;
 268
 269         read_lock(&protocol_list_lock);
 270         for (protocol = protocol_list; protocol != NULL; protocol = protocol->next)
 271                 if (protocol->pid == pid) {
 272                         res = 1;
 273                         break;
 274                 }
 275         read_unlock(&protocol_list_lock);
 276
 277         return res;
 278 }