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/sched.h>
  16 #include <linux/spinlock.h>
  17 #include <linux/timer.h>
  18 #include <linux/string.h>
  19 #include <linux/sockios.h>
  20 #include <linux/net.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 *s, *protocol;
  62
  63         write_lock_bh(&protocol_list_lock);
  64         protocol = protocol_list;
  65         if (protocol == NULL) {
  66                 write_unlock_bh(&protocol_list_lock);
  67                 return;
  68         }
  69
  70         if (protocol->pid == pid) {
  71                 protocol_list = protocol->next;
  72                 write_unlock_bh(&protocol_list_lock);
  73                 kfree(protocol);
  74                 return;
  75         }
  76
  77         while (protocol != NULL && protocol->next != NULL) {
  78                 if (protocol->next->pid == pid) {
  79                         s = protocol->next;
  80                         protocol->next = protocol->next->next;
  81                         write_unlock_bh(&protocol_list_lock);
  82                         kfree(s);
  83                         return;
  84                 }
  85
  86                 protocol = protocol->next;
  87         }
  88         write_unlock_bh(&protocol_list_lock);
  89 }
  90
  91 EXPORT_SYMBOL(ax25_protocol_release);
  92
  93 void ax25_linkfail_register(struct ax25_linkfail *lf)
  94 {
  95         spin_lock_bh(&linkfail_lock);
  96         hlist_add_head(&lf->lf_node, &ax25_linkfail_list);
  97         spin_unlock_bh(&linkfail_lock);
  98 }
  99
 100 EXPORT_SYMBOL(ax25_linkfail_register);
 101
 102 void ax25_linkfail_release(struct ax25_linkfail *lf)
 103 {
 104         spin_lock_bh(&linkfail_lock);
 105         hlist_del_init(&lf->lf_node);
 106         spin_unlock_bh(&linkfail_lock);
 107 }
 108
 109 EXPORT_SYMBOL(ax25_linkfail_release);
 110
 111 int ax25_listen_register(ax25_address *callsign, struct net_device *dev)
 112 {
 113         struct listen_struct *listen;
 114
 115         if (ax25_listen_mine(callsign, dev))
 116                 return 0;
 117
 118         if ((listen = kmalloc(sizeof(*listen), GFP_ATOMIC)) == NULL)
 119                 return -ENOMEM;
 120
 121         listen->callsign = *callsign;
 122         listen->dev      = dev;
 123
 124         spin_lock_bh(&listen_lock);
 125         listen->next = listen_list;
 126         listen_list  = listen;
 127         spin_unlock_bh(&listen_lock);
 128
 129         return 0;
 130 }
 131
 132 EXPORT_SYMBOL(ax25_listen_register);
 133
 134 void ax25_listen_release(ax25_address *callsign, struct net_device *dev)
 135 {
 136         struct listen_struct *s, *listen;
 137
 138         spin_lock_bh(&listen_lock);
 139         listen = listen_list;
 140         if (listen == NULL) {
 141                 spin_unlock_bh(&listen_lock);
 142                 return;
 143         }
 144
 145         if (ax25cmp(&listen->callsign, callsign) == 0 && listen->dev == dev) {
 146                 listen_list = listen->next;
 147                 spin_unlock_bh(&listen_lock);
 148                 kfree(listen);
 149                 return;
 150         }
 151
 152         while (listen != NULL && listen->next != NULL) {
 153                 if (ax25cmp(&listen->next->callsign, callsign) == 0 && listen->next->dev == dev) {
 154                         s = listen->next;
 155                         listen->next = listen->next->next;
 156                         spin_unlock_bh(&listen_lock);
 157                         kfree(s);
 158                         return;
 159                 }
 160
 161                 listen = listen->next;
 162         }
 163         spin_unlock_bh(&listen_lock);
 164 }
 165
 166 EXPORT_SYMBOL(ax25_listen_release);
 167
 168 int (*ax25_protocol_function(unsigned int pid))(struct sk_buff *, ax25_cb *)
 169 {
 170         int (*res)(struct sk_buff *, ax25_cb *) = NULL;
 171         struct ax25_protocol *protocol;
 172
 173         read_lock(&protocol_list_lock);
 174         for (protocol = protocol_list; protocol != NULL; protocol = protocol->next)
 175                 if (protocol->pid == pid) {
 176                         res = protocol->func;
 177                         break;
 178                 }
 179         read_unlock(&protocol_list_lock);
 180
 181         return res;
 182 }
 183
 184 int ax25_listen_mine(ax25_address *callsign, struct net_device *dev)
 185 {
 186         struct listen_struct *listen;
 187
 188         spin_lock_bh(&listen_lock);
 189         for (listen = listen_list; listen != NULL; listen = listen->next)
 190                 if (ax25cmp(&listen->callsign, callsign) == 0 &&
 191                     (listen->dev == dev || listen->dev == NULL)) {
 192                         spin_unlock_bh(&listen_lock);
 193                         return 1;
 194         }
 195         spin_unlock_bh(&listen_lock);
 196
 197         return 0;
 198 }
 199
 200 void ax25_link_failed(ax25_cb *ax25, int reason)
 201 {
 202         struct ax25_linkfail *lf;
 203         struct hlist_node *node;
 204
 205         spin_lock_bh(&linkfail_lock);
 206         hlist_for_each_entry(lf, node, &ax25_linkfail_list, lf_node)
 207                 lf->func(ax25, reason);
 208         spin_unlock_bh(&linkfail_lock);
 209 }
 210
 211 int ax25_protocol_is_registered(unsigned int pid)
 212 {
 213         struct ax25_protocol *protocol;
 214         int res = 0;
 215
 216         read_lock_bh(&protocol_list_lock);
 217         for (protocol = protocol_list; protocol != NULL; protocol = protocol->next)
 218                 if (protocol->pid == pid) {
 219                         res = 1;
 220                         break;
 221                 }
 222         read_unlock_bh(&protocol_list_lock);
 223
 224         return res;
 225 }