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