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 <asm/system.h>
  28#include <linux/fcntl.h>
  29#include <linux/mm.h>
  30#include <linux/interrupt.h>
  31
  32static struct ax25_protocol *protocol_list;
  33static DEFINE_RWLOCK(protocol_list_lock);
  34
  35static HLIST_HEAD(ax25_linkfail_list);
  36static DEFINE_SPINLOCK(linkfail_lock);
  37
  38static struct listen_struct {
  39        struct listen_struct *next;
  40        ax25_address  callsign;
  41        struct net_device *dev;
  42} *listen_list = NULL;
  43static 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 */
  49void 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
  57EXPORT_SYMBOL_GPL(ax25_register_pid);
  58
  59void 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        }
  81out:
  82        write_unlock_bh(&protocol_list_lock);
  83}
  84
  85EXPORT_SYMBOL(ax25_protocol_release);
  86
  87void 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
  94EXPORT_SYMBOL(ax25_linkfail_register);
  95
  96void 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
 103EXPORT_SYMBOL(ax25_linkfail_release);
 104
 105int 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
 126EXPORT_SYMBOL(ax25_listen_register);
 127
 128void 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
 160EXPORT_SYMBOL(ax25_listen_release);
 161
 162int (*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
 178int 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
 194void 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
 205int 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}
 220