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