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 <net/ax25.h>
  21 #include <linux/inet.h>
  22 #include <linux/netdevice.h>
  23 #include <linux/skbuff.h>
  24 #include <net/sock.h>
  25 #include <asm/uaccess.h>
  26 #include <asm/system.h>
  27 #include <linux/fcntl.h>
  28 #include <linux/mm.h>
  29 #include <linux/interrupt.h>
  30
  31 static struct ax25_protocol *protocol_list;
  32 static DEFINE_RWLOCK(protocol_list_lock);
  33
  34 static HLIST_HEAD(ax25_linkfail_list);
  35 static DEFINE_SPINLOCK(linkfail_lock);
  36
  37 static struct listen_struct {
  38         struct listen_struct *next;
  39         ax25_address  callsign;
  40         struct net_device *dev;
  41 } *listen_list = NULL;
  42 static DEFINE_SPINLOCK(listen_lock);
  43
  44 /*
  45  * Do not register the internal protocols AX25_P_TEXT, AX25_P_SEGMENT,
  46  * AX25_P_IP or AX25_P_ARP ...
  47  */
  48 void ax25_register_pid(struct ax25_protocol *ap)
  49 {
  50         write_lock_bh(&protocol_list_lock);
  51         ap->next = protocol_list;
  52         protocol_list = ap;
  53         write_unlock_bh(&protocol_list_lock);
  54 }
  55
  56 EXPORT_SYMBOL_GPL(ax25_register_pid);
  57
  58 void ax25_protocol_release(unsigned int pid)
  59 {
  60         struct ax25_protocol *s, *protocol;
  61
  62         write_lock_bh(&protocol_list_lock);
  63         protocol = protocol_list;
  64         if (protocol == NULL) {
  65                 write_unlock_bh(&protocol_list_lock);
  66                 return;
  67         }
  68
  69         if (protocol->pid == pid) {
  70                 protocol_list = protocol->next;
  71                 write_unlock_bh(&protocol_list_lock);
  72                 kfree(protocol);
  73                 return;
  74         }
  75
  76         while (protocol != NULL && protocol->next != NULL) {
  77                 if (protocol->next->pid == pid) {
  78                         s = protocol->next;
  79                         protocol->next = protocol->next->next;
  80                         write_unlock_bh(&protocol_list_lock);
  81                         kfree(s);
  82                         return;
  83                 }
  84
  85                 protocol = protocol->next;
  86         }
  87         write_unlock_bh(&protocol_list_lock);
  88 }
  89
  90 EXPORT_SYMBOL(ax25_protocol_release);
  91
  92 void ax25_linkfail_register(struct ax25_linkfail *lf)
  93 {
  94         spin_lock_bh(&linkfail_lock);
  95         hlist_add_head(&lf->lf_node, &ax25_linkfail_list);
  96         spin_unlock_bh(&linkfail_lock);
  97 }
  98
  99 EXPORT_SYMBOL(ax25_linkfail_register);
 100
 101 void ax25_linkfail_release(struct ax25_linkfail *lf)
 102 {
 103         spin_lock_bh(&linkfail_lock);
 104         hlist_del_init(&lf->lf_node);
 105         spin_unlock_bh(&linkfail_lock);
 106 }
 107
 108 EXPORT_SYMBOL(ax25_linkfail_release);
 109
 110 int ax25_listen_register(ax25_address *callsign, struct net_device *dev)
 111 {
 112         struct listen_struct *listen;
 113
 114         if (ax25_listen_mine(callsign, dev))
 115                 return 0;
 116
 117         if ((listen = kmalloc(sizeof(*listen), GFP_ATOMIC)) == NULL)
 118                 return -ENOMEM;
 119
 120         listen->callsign = *callsign;
 121         listen->dev      = dev;
 122
 123         spin_lock_bh(&listen_lock);
 124         listen->next = listen_list;
 125         listen_list  = listen;
 126         spin_unlock_bh(&listen_lock);
 127
 128         return 0;
 129 }
 130
 131 EXPORT_SYMBOL(ax25_listen_register);
 132
 133 void ax25_listen_release(ax25_address *callsign, struct net_device *dev)
 134 {
 135         struct listen_struct *s, *listen;
 136
 137         spin_lock_bh(&listen_lock);
 138         listen = listen_list;
 139         if (listen == NULL) {
 140                 spin_unlock_bh(&listen_lock);
 141                 return;
 142         }
 143
 144         if (ax25cmp(&listen->callsign, callsign) == 0 && listen->dev == dev) {
 145                 listen_list = listen->next;
 146                 spin_unlock_bh(&listen_lock);
 147                 kfree(listen);
 148                 return;
 149         }
 150
 151         while (listen != NULL && listen->next != NULL) {
 152                 if (ax25cmp(&listen->next->callsign, callsign) == 0 && listen->next->dev == dev) {
 153                         s = listen->next;
 154                         listen->next = listen->next->next;
 155                         spin_unlock_bh(&listen_lock);
 156                         kfree(s);
 157                         return;
 158                 }
 159
 160                 listen = listen->next;
 161         }
 162         spin_unlock_bh(&listen_lock);
 163 }
 164
 165 EXPORT_SYMBOL(ax25_listen_release);
 166
 167 int (*ax25_protocol_function(unsigned int pid))(struct sk_buff *, ax25_cb *)
 168 {
 169         int (*res)(struct sk_buff *, ax25_cb *) = NULL;
 170         struct ax25_protocol *protocol;
 171
 172         read_lock(&protocol_list_lock);
 173         for (protocol = protocol_list; protocol != NULL; protocol = protocol->next)
 174                 if (protocol->pid == pid) {
 175                         res = protocol->func;
 176                         break;
 177                 }
 178         read_unlock(&protocol_list_lock);
 179
 180         return res;
 181 }
 182
 183 int ax25_listen_mine(ax25_address *callsign, struct net_device *dev)
 184 {
 185         struct listen_struct *listen;
 186
 187         spin_lock_bh(&listen_lock);
 188         for (listen = listen_list; listen != NULL; listen = listen->next)
 189                 if (ax25cmp(&listen->callsign, callsign) == 0 &&
 190                     (listen->dev == dev || listen->dev == NULL)) {
 191                         spin_unlock_bh(&listen_lock);
 192                         return 1;
 193         }
 194         spin_unlock_bh(&listen_lock);
 195
 196         return 0;
 197 }
 198
 199 void ax25_link_failed(ax25_cb *ax25, int reason)
 200 {
 201         struct ax25_linkfail *lf;
 202         struct hlist_node *node;
 203
 204         spin_lock_bh(&linkfail_lock);
 205         hlist_for_each_entry(lf, node, &ax25_linkfail_list, lf_node)
 206                 lf->func(ax25, reason);
 207         spin_unlock_bh(&linkfail_lock);
 208 }
 209
 210 int ax25_protocol_is_registered(unsigned int pid)
 211 {
 212         struct ax25_protocol *protocol;
 213         int res = 0;
 214
 215         read_lock_bh(&protocol_list_lock);
 216         for (protocol = protocol_list; protocol != NULL; protocol = protocol->next)
 217                 if (protocol->pid == pid) {
 218                         res = 1;
 219                         break;
 220                 }
 221         read_unlock_bh(&protocol_list_lock);
 222
 223         return res;
 224 }