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/config.h>
  10 #include <linux/errno.h>
  11 #include <linux/types.h>
  12 #include <linux/socket.h>
  13 #include <linux/in.h>
  14 #include <linux/kernel.h>
  15 #include <linux/module.h>
  16 #include <linux/sched.h>
  17 #include <linux/spinlock.h>
  18 #include <linux/timer.h>
  19 #include <linux/string.h>
  20 #include <linux/sockios.h>
  21 #include <linux/net.h>
  22 #include <net/ax25.h>
  23 #include <linux/inet.h>
  24 #include <linux/netdevice.h>
  25 #include <linux/skbuff.h>
  26 #include <net/sock.h>
  27 #include <asm/uaccess.h>
  28 #include <asm/system.h>
  29 #include <linux/fcntl.h>
  30 #include <linux/mm.h>
  31 #include <linux/interrupt.h>
  32
  33 static struct protocol_struct {
  34         struct protocol_struct *next;
  35         unsigned int pid;
  36         int (*func)(struct sk_buff *, ax25_cb *);
  37 } *protocol_list = NULL;
  38 static DEFINE_RWLOCK(protocol_list_lock);
  39
  40 static struct linkfail_struct {
  41         struct linkfail_struct *next;
  42         void (*func)(ax25_cb *, int);
  43 } *linkfail_list = NULL;
  44 static DEFINE_SPINLOCK(linkfail_lock);
  45
  46 static struct listen_struct {
  47         struct listen_struct *next;
  48         ax25_address  callsign;
  49         struct net_device *dev;
  50 } *listen_list = NULL;
  51 static DEFINE_SPINLOCK(listen_lock);
  52
  53 int ax25_protocol_register(unsigned int pid,
  54         int (*func)(struct sk_buff *, ax25_cb *))
  55 {
  56         struct protocol_struct *protocol;
  57
  58         if (pid == AX25_P_TEXT || pid == AX25_P_SEGMENT)
  59                 return 0;
  60 #ifdef CONFIG_INET
  61         if (pid == AX25_P_IP || pid == AX25_P_ARP)
  62                 return 0;
  63 #endif
  64         if ((protocol = kmalloc(sizeof(*protocol), GFP_ATOMIC)) == NULL)
  65                 return 0;
  66
  67         protocol->pid  = pid;
  68         protocol->func = func;
  69
  70         write_lock(&protocol_list_lock);
  71         protocol->next = protocol_list;
  72         protocol_list  = protocol;
  73         write_unlock(&protocol_list_lock);
  74
  75         return 1;
  76 }
  77
  78 EXPORT_SYMBOL(ax25_protocol_register);
  79
  80 void ax25_protocol_release(unsigned int pid)
  81 {
  82         struct protocol_struct *s, *protocol;
  83
  84         write_lock(&protocol_list_lock);
  85         protocol = protocol_list;
  86         if (protocol == NULL) {
  87                 write_unlock(&protocol_list_lock);
  88                 return;
  89         }
  90
  91         if (protocol->pid == pid) {
  92                 protocol_list = protocol->next;
  93                 write_unlock(&protocol_list_lock);
  94                 kfree(protocol);
  95                 return;
  96         }
  97
  98         while (protocol != NULL && protocol->next != NULL) {
  99                 if (protocol->next->pid == pid) {
 100                         s = protocol->next;
 101                         protocol->next = protocol->next->next;
 102                         write_unlock(&protocol_list_lock);
 103                         kfree(s);
 104                         return;
 105                 }
 106
 107                 protocol = protocol->next;
 108         }
 109         write_unlock(&protocol_list_lock);
 110 }
 111
 112 EXPORT_SYMBOL(ax25_protocol_release);
 113
 114 int ax25_linkfail_register(void (*func)(ax25_cb *, int))
 115 {
 116         struct linkfail_struct *linkfail;
 117
 118         if ((linkfail = kmalloc(sizeof(*linkfail), GFP_ATOMIC)) == NULL)
 119                 return 0;
 120
 121         linkfail->func = func;
 122
 123         spin_lock_bh(&linkfail_lock);
 124         linkfail->next = linkfail_list;
 125         linkfail_list  = linkfail;
 126         spin_unlock_bh(&linkfail_lock);
 127
 128         return 1;
 129 }
 130
 131 EXPORT_SYMBOL(ax25_linkfail_register);
 132
 133 void ax25_linkfail_release(void (*func)(ax25_cb *, int))
 134 {
 135         struct linkfail_struct *s, *linkfail;
 136
 137         spin_lock_bh(&linkfail_lock);
 138         linkfail = linkfail_list;
 139         if (linkfail == NULL) {
 140                 spin_unlock_bh(&linkfail_lock);
 141                 return;
 142         }
 143
 144         if (linkfail->func == func) {
 145                 linkfail_list = linkfail->next;
 146                 spin_unlock_bh(&linkfail_lock);
 147                 kfree(linkfail);
 148                 return;
 149         }
 150
 151         while (linkfail != NULL && linkfail->next != NULL) {
 152                 if (linkfail->next->func == func) {
 153                         s = linkfail->next;
 154                         linkfail->next = linkfail->next->next;
 155                         spin_unlock_bh(&linkfail_lock);
 156                         kfree(s);
 157                         return;
 158                 }
 159
 160                 linkfail = linkfail->next;
 161         }
 162         spin_unlock_bh(&linkfail_lock);
 163 }
 164
 165 EXPORT_SYMBOL(ax25_linkfail_release);
 166
 167 int ax25_listen_register(ax25_address *callsign, struct net_device *dev)
 168 {
 169         struct listen_struct *listen;
 170
 171         if (ax25_listen_mine(callsign, dev))
 172                 return 0;
 173
 174         if ((listen = kmalloc(sizeof(*listen), GFP_ATOMIC)) == NULL)
 175                 return 0;
 176
 177         listen->callsign = *callsign;
 178         listen->dev      = dev;
 179
 180         spin_lock_bh(&listen_lock);
 181         listen->next = listen_list;
 182         listen_list  = listen;
 183         spin_unlock_bh(&listen_lock);
 184
 185         return 1;
 186 }
 187
 188 EXPORT_SYMBOL(ax25_listen_register);
 189
 190 void ax25_listen_release(ax25_address *callsign, struct net_device *dev)
 191 {
 192         struct listen_struct *s, *listen;
 193
 194         spin_lock_bh(&listen_lock);
 195         listen = listen_list;
 196         if (listen == NULL) {
 197                 spin_unlock_bh(&listen_lock);
 198                 return;
 199         }
 200
 201         if (ax25cmp(&listen->callsign, callsign) == 0 && listen->dev == dev) {
 202                 listen_list = listen->next;
 203                 spin_unlock_bh(&listen_lock);
 204                 kfree(listen);
 205                 return;
 206         }
 207
 208         while (listen != NULL && listen->next != NULL) {
 209                 if (ax25cmp(&listen->next->callsign, callsign) == 0 && listen->next->dev == dev) {
 210                         s = listen->next;
 211                         listen->next = listen->next->next;
 212                         spin_unlock_bh(&listen_lock);
 213                         kfree(s);
 214                         return;
 215                 }
 216
 217                 listen = listen->next;
 218         }
 219         spin_unlock_bh(&listen_lock);
 220 }
 221
 222 EXPORT_SYMBOL(ax25_listen_release);
 223
 224 int (*ax25_protocol_function(unsigned int pid))(struct sk_buff *, ax25_cb *)
 225 {
 226         int (*res)(struct sk_buff *, ax25_cb *) = NULL;
 227         struct protocol_struct *protocol;
 228
 229         read_lock(&protocol_list_lock);
 230         for (protocol = protocol_list; protocol != NULL; protocol = protocol->next)
 231                 if (protocol->pid == pid) {
 232                         res = protocol->func;
 233                         break;
 234                 }
 235         read_unlock(&protocol_list_lock);
 236
 237         return res;
 238 }
 239
 240 int ax25_listen_mine(ax25_address *callsign, struct net_device *dev)
 241 {
 242         struct listen_struct *listen;
 243
 244         spin_lock_bh(&listen_lock);
 245         for (listen = listen_list; listen != NULL; listen = listen->next)
 246                 if (ax25cmp(&listen->callsign, callsign) == 0 && (listen->dev == dev || listen->dev == NULL)) {
 247                         spin_unlock_bh(&listen_lock);
 248                         return 1;
 249         }
 250         spin_unlock_bh(&listen_lock);
 251
 252         return 0;
 253 }
 254
 255 void ax25_link_failed(ax25_cb *ax25, int reason)
 256 {
 257         struct linkfail_struct *linkfail;
 258
 259         spin_lock_bh(&linkfail_lock);
 260         for (linkfail = linkfail_list; linkfail != NULL; linkfail = linkfail->next)
 261                 (linkfail->func)(ax25, reason);
 262         spin_unlock_bh(&linkfail_lock);
 263 }
 264
 265 int ax25_protocol_is_registered(unsigned int pid)
 266 {
 267         struct protocol_struct *protocol;
 268         int res = 0;
 269
 270         read_lock(&protocol_list_lock);
 271         for (protocol = protocol_list; protocol != NULL; protocol = protocol->next)
 272                 if (protocol->pid == pid) {
 273                         res = 1;
 274                         break;
 275                 }
 276         read_unlock(&protocol_list_lock);
 277
 278         return res;
 279 }