linux/net/ax25/ax25_iface.c
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   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 <linux/fcntl.h>
  28#include <linux/mm.h>
  29#include <linux/interrupt.h>
  30
  31static struct ax25_protocol *protocol_list;
  32static DEFINE_RWLOCK(protocol_list_lock);
  33
  34static HLIST_HEAD(ax25_linkfail_list);
  35static DEFINE_SPINLOCK(linkfail_lock);
  36
  37static struct listen_struct {
  38        struct listen_struct *next;
  39        ax25_address  callsign;
  40        struct net_device *dev;
  41} *listen_list = NULL;
  42static 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 */
  48void 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
  56EXPORT_SYMBOL_GPL(ax25_register_pid);
  57
  58void 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        }
  80out:
  81        write_unlock_bh(&protocol_list_lock);
  82}
  83
  84EXPORT_SYMBOL(ax25_protocol_release);
  85
  86void 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
  93EXPORT_SYMBOL(ax25_linkfail_register);
  94
  95void 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
 102EXPORT_SYMBOL(ax25_linkfail_release);
 103
 104int 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
 125EXPORT_SYMBOL(ax25_listen_register);
 126
 127void 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
 159EXPORT_SYMBOL(ax25_listen_release);
 160
 161int (*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
 177int 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
 193void ax25_link_failed(ax25_cb *ax25, int reason)
 194{
 195        struct ax25_linkfail *lf;
 196        struct hlist_node *node;
 197
 198        spin_lock_bh(&linkfail_lock);
 199        hlist_for_each_entry(lf, node, &ax25_linkfail_list, lf_node)
 200                lf->func(ax25, reason);
 201        spin_unlock_bh(&linkfail_lock);
 202}
 203
 204int ax25_protocol_is_registered(unsigned int pid)
 205{
 206        struct ax25_protocol *protocol;
 207        int res = 0;
 208
 209        read_lock_bh(&protocol_list_lock);
 210        for (protocol = protocol_list; protocol != NULL; protocol = protocol->next)
 211                if (protocol->pid == pid) {
 212                        res = 1;
 213                        break;
 214                }
 215        read_unlock_bh(&protocol_list_lock);
 216
 217        return res;
 218}
 219
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