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 <linux/uaccess.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 *protocol;
  61
  62         write_lock_bh(&protocol_list_lock);
  63         protocol = protocol_list;
  64         if (protocol == NULL)
  65                 goto out;
  66
  67         if (protocol->pid == pid) {
  68                 protocol_list = protocol->next;
  69                 goto out;
  70         }
  71
  72         while (protocol != NULL && protocol->next != NULL) {
  73                 if (protocol->next->pid == pid) {
  74                         protocol->next = protocol->next->next;
  75                         goto out;
  76                 }
  77
  78                 protocol = protocol->next;
  79         }
  80 out:
  81         write_unlock_bh(&protocol_list_lock);
  82 }
  83
  84 EXPORT_SYMBOL(ax25_protocol_release);
  85
  86 void ax25_linkfail_register(struct ax25_linkfail *lf)
  87 {
  88         spin_lock_bh(&linkfail_lock);
  89         hlist_add_head(&lf->lf_node, &ax25_linkfail_list);
  90         spin_unlock_bh(&linkfail_lock);
  91 }
  92
  93 EXPORT_SYMBOL(ax25_linkfail_register);
  94
  95 void ax25_linkfail_release(struct ax25_linkfail *lf)
  96 {
  97         spin_lock_bh(&linkfail_lock);
  98         hlist_del_init(&lf->lf_node);
  99         spin_unlock_bh(&linkfail_lock);
 100 }
 101
 102 EXPORT_SYMBOL(ax25_linkfail_release);
 103
 104 int ax25_listen_register(ax25_address *callsign, struct net_device *dev)
 105 {
 106         struct listen_struct *listen;
 107
 108         if (ax25_listen_mine(callsign, dev))
 109                 return 0;
 110
 111         if ((listen = kmalloc(sizeof(*listen), GFP_ATOMIC)) == NULL)
 112                 return -ENOMEM;
 113
 114         listen->callsign = *callsign;
 115         listen->dev      = dev;
 116
 117         spin_lock_bh(&listen_lock);
 118         listen->next = listen_list;
 119         listen_list  = listen;
 120         spin_unlock_bh(&listen_lock);
 121
 122         return 0;
 123 }
 124
 125 EXPORT_SYMBOL(ax25_listen_register);
 126
 127 void ax25_listen_release(ax25_address *callsign, struct net_device *dev)
 128 {
 129         struct listen_struct *s, *listen;
 130
 131         spin_lock_bh(&listen_lock);
 132         listen = listen_list;
 133         if (listen == NULL) {
 134                 spin_unlock_bh(&listen_lock);
 135                 return;
 136         }
 137
 138         if (ax25cmp(&listen->callsign, callsign) == 0 && listen->dev == dev) {
 139                 listen_list = listen->next;
 140                 spin_unlock_bh(&listen_lock);
 141                 kfree(listen);
 142                 return;
 143         }
 144
 145         while (listen != NULL && listen->next != NULL) {
 146                 if (ax25cmp(&listen->next->callsign, callsign) == 0 && listen->next->dev == dev) {
 147                         s = listen->next;
 148                         listen->next = listen->next->next;
 149                         spin_unlock_bh(&listen_lock);
 150                         kfree(s);
 151                         return;
 152                 }
 153
 154                 listen = listen->next;
 155         }
 156         spin_unlock_bh(&listen_lock);
 157 }
 158
 159 EXPORT_SYMBOL(ax25_listen_release);
 160
 161 int (*ax25_protocol_function(unsigned int pid))(struct sk_buff *, ax25_cb *)
 162 {
 163         int (*res)(struct sk_buff *, ax25_cb *) = NULL;
 164         struct ax25_protocol *protocol;
 165
 166         read_lock(&protocol_list_lock);
 167         for (protocol = protocol_list; protocol != NULL; protocol = protocol->next)
 168                 if (protocol->pid == pid) {
 169                         res = protocol->func;
 170                         break;
 171                 }
 172         read_unlock(&protocol_list_lock);
 173
 174         return res;
 175 }
 176
 177 int ax25_listen_mine(ax25_address *callsign, struct net_device *dev)
 178 {
 179         struct listen_struct *listen;
 180
 181         spin_lock_bh(&listen_lock);
 182         for (listen = listen_list; listen != NULL; listen = listen->next)
 183                 if (ax25cmp(&listen->callsign, callsign) == 0 &&
 184                     (listen->dev == dev || listen->dev == NULL)) {
 185                         spin_unlock_bh(&listen_lock);
 186                         return 1;
 187         }
 188         spin_unlock_bh(&listen_lock);
 189
 190         return 0;
 191 }
 192
 193 void ax25_link_failed(ax25_cb *ax25, int reason)
 194 {
 195         struct ax25_linkfail *lf;
 196
 197         spin_lock_bh(&linkfail_lock);
 198         hlist_for_each_entry(lf, &ax25_linkfail_list, lf_node)
 199                 lf->func(ax25, reason);
 200         spin_unlock_bh(&linkfail_lock);
 201 }
 202
 203 int ax25_protocol_is_registered(unsigned int pid)
 204 {
 205         struct ax25_protocol *protocol;
 206         int res = 0;
 207
 208         read_lock_bh(&protocol_list_lock);
 209         for (protocol = protocol_list; protocol != NULL; protocol = protocol->next)
 210                 if (protocol->pid == pid) {
 211                         res = 1;
 212                         break;
 213                 }
 214         read_unlock_bh(&protocol_list_lock);
 215
 216         return res;
 217 }