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                 return;
  73         }
  74
  75         while (protocol != NULL && protocol->next != NULL) {
  76                 if (protocol->next->pid == pid) {
  77                         s = protocol->next;
  78                         protocol->next = protocol->next->next;
  79                         write_unlock_bh(&protocol_list_lock);
  80                         return;
  81                 }
  82
  83                 protocol = protocol->next;
  84         }
  85         write_unlock_bh(&protocol_list_lock);
  86 }
  87
  88 EXPORT_SYMBOL(ax25_protocol_release);
  89
  90 void ax25_linkfail_register(struct ax25_linkfail *lf)
  91 {
  92         spin_lock_bh(&linkfail_lock);
  93         hlist_add_head(&lf->lf_node, &ax25_linkfail_list);
  94         spin_unlock_bh(&linkfail_lock);
  95 }
  96
  97 EXPORT_SYMBOL(ax25_linkfail_register);
  98
  99 void ax25_linkfail_release(struct ax25_linkfail *lf)
 100 {
 101         spin_lock_bh(&linkfail_lock);
 102         hlist_del_init(&lf->lf_node);
 103         spin_unlock_bh(&linkfail_lock);
 104 }
 105
 106 EXPORT_SYMBOL(ax25_linkfail_release);
 107
 108 int ax25_listen_register(ax25_address *callsign, struct net_device *dev)
 109 {
 110         struct listen_struct *listen;
 111
 112         if (ax25_listen_mine(callsign, dev))
 113                 return 0;
 114
 115         if ((listen = kmalloc(sizeof(*listen), GFP_ATOMIC)) == NULL)
 116                 return -ENOMEM;
 117
 118         listen->callsign = *callsign;
 119         listen->dev      = dev;
 120
 121         spin_lock_bh(&listen_lock);
 122         listen->next = listen_list;
 123         listen_list  = listen;
 124         spin_unlock_bh(&listen_lock);
 125
 126         return 0;
 127 }
 128
 129 EXPORT_SYMBOL(ax25_listen_register);
 130
 131 void ax25_listen_release(ax25_address *callsign, struct net_device *dev)
 132 {
 133         struct listen_struct *s, *listen;
 134
 135         spin_lock_bh(&listen_lock);
 136         listen = listen_list;
 137         if (listen == NULL) {
 138                 spin_unlock_bh(&listen_lock);
 139                 return;
 140         }
 141
 142         if (ax25cmp(&listen->callsign, callsign) == 0 && listen->dev == dev) {
 143                 listen_list = listen->next;
 144                 spin_unlock_bh(&listen_lock);
 145                 kfree(listen);
 146                 return;
 147         }
 148
 149         while (listen != NULL && listen->next != NULL) {
 150                 if (ax25cmp(&listen->next->callsign, callsign) == 0 && listen->next->dev == dev) {
 151                         s = listen->next;
 152                         listen->next = listen->next->next;
 153                         spin_unlock_bh(&listen_lock);
 154                         kfree(s);
 155                         return;
 156                 }
 157
 158                 listen = listen->next;
 159         }
 160         spin_unlock_bh(&listen_lock);
 161 }
 162
 163 EXPORT_SYMBOL(ax25_listen_release);
 164
 165 int (*ax25_protocol_function(unsigned int pid))(struct sk_buff *, ax25_cb *)
 166 {
 167         int (*res)(struct sk_buff *, ax25_cb *) = NULL;
 168         struct ax25_protocol *protocol;
 169
 170         read_lock(&protocol_list_lock);
 171         for (protocol = protocol_list; protocol != NULL; protocol = protocol->next)
 172                 if (protocol->pid == pid) {
 173                         res = protocol->func;
 174                         break;
 175                 }
 176         read_unlock(&protocol_list_lock);
 177
 178         return res;
 179 }
 180
 181 int ax25_listen_mine(ax25_address *callsign, struct net_device *dev)
 182 {
 183         struct listen_struct *listen;
 184
 185         spin_lock_bh(&listen_lock);
 186         for (listen = listen_list; listen != NULL; listen = listen->next)
 187                 if (ax25cmp(&listen->callsign, callsign) == 0 &&
 188                     (listen->dev == dev || listen->dev == NULL)) {
 189                         spin_unlock_bh(&listen_lock);
 190                         return 1;
 191         }
 192         spin_unlock_bh(&listen_lock);
 193
 194         return 0;
 195 }
 196
 197 void ax25_link_failed(ax25_cb *ax25, int reason)
 198 {
 199         struct ax25_linkfail *lf;
 200         struct hlist_node *node;
 201
 202         spin_lock_bh(&linkfail_lock);
 203         hlist_for_each_entry(lf, node, &ax25_linkfail_list, lf_node)
 204                 lf->func(ax25, reason);
 205         spin_unlock_bh(&linkfail_lock);
 206 }
 207
 208 int ax25_protocol_is_registered(unsigned int pid)
 209 {
 210         struct ax25_protocol *protocol;
 211         int res = 0;
 212
 213         read_lock_bh(&protocol_list_lock);
 214         for (protocol = protocol_list; protocol != NULL; protocol = protocol->next)
 215                 if (protocol->pid == pid) {
 216                         res = 1;
 217                         break;
 218                 }
 219         read_unlock_bh(&protocol_list_lock);
 220
 221         return res;
 222 }