/*
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
 */
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <net/ax25.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <asm/uaccess.h>
#include <asm/system.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/interrupt.h>

static struct ax25_protocol *protocol_list;
static DEFINE_RWLOCK(protocol_list_lock);

static HLIST_HEAD(ax25_linkfail_list);
static DEFINE_SPINLOCK(linkfail_lock);

static struct listen_struct {
        struct listen_struct *next;
        ax25_address  callsign;
        struct net_device *dev;
} *listen_list = NULL;
static DEFINE_SPINLOCK(listen_lock);

/*
 * Do not register the internal protocols AX25_P_TEXT, AX25_P_SEGMENT,
 * AX25_P_IP or AX25_P_ARP ...
 */
void ax25_register_pid(struct ax25_protocol *ap)
{
        write_lock_bh(&protocol_list_lock);
        ap->next = protocol_list;
        protocol_list = ap;
        write_unlock_bh(&protocol_list_lock);
}

EXPORT_SYMBOL_GPL(ax25_register_pid);

void ax25_protocol_release(unsigned int pid)
{
        struct ax25_protocol *s, *protocol;

        write_lock_bh(&protocol_list_lock);
        protocol = protocol_list;
        if (protocol == NULL)
                goto out;

        if (protocol->pid == pid) {
                protocol_list = protocol->next;
                goto out;
        }

        while (protocol != NULL && protocol->next != NULL) {
                if (protocol->next->pid == pid) {
                        s = protocol->next;
                        protocol->next = protocol->next->next;
                        goto out;
                }

                protocol = protocol->next;
        }
out:
        write_unlock_bh(&protocol_list_lock);
}

EXPORT_SYMBOL(ax25_protocol_release);

void ax25_linkfail_register(struct ax25_linkfail *lf)
{
        spin_lock_bh(&linkfail_lock);
        hlist_add_head(&lf->lf_node, &ax25_linkfail_list);
        spin_unlock_bh(&linkfail_lock);
}

EXPORT_SYMBOL(ax25_linkfail_register);

void ax25_linkfail_release(struct ax25_linkfail *lf)
{
        spin_lock_bh(&linkfail_lock);
        hlist_del_init(&lf->lf_node);
        spin_unlock_bh(&linkfail_lock);
}

EXPORT_SYMBOL(ax25_linkfail_release);

int ax25_listen_register(ax25_address *callsign, struct net_device *dev)
{
        struct listen_struct *listen;

        if (ax25_listen_mine(callsign, dev))
                return 0;

        if ((listen = kmalloc(sizeof(*listen), GFP_ATOMIC)) == NULL)
                return -ENOMEM;

        listen->callsign = *callsign;
        listen->dev      = dev;

        spin_lock_bh(&listen_lock);
        listen->next = listen_list;
        listen_list  = listen;
        spin_unlock_bh(&listen_lock);

        return 0;
}

EXPORT_SYMBOL(ax25_listen_register);

void ax25_listen_release(ax25_address *callsign, struct net_device *dev)
{
        struct listen_struct *s, *listen;

        spin_lock_bh(&listen_lock);
        listen = listen_list;
        if (listen == NULL) {
                spin_unlock_bh(&listen_lock);
                return;
        }

        if (ax25cmp(&listen->callsign, callsign) == 0 && listen->dev == dev) {
                listen_list = listen->next;
                spin_unlock_bh(&listen_lock);
                kfree(listen);
                return;
        }

        while (listen != NULL && listen->next != NULL) {
                if (ax25cmp(&listen->next->callsign, callsign) == 0 && listen->next->dev == dev) {
                        s = listen->next;
                        listen->next = listen->next->next;
                        spin_unlock_bh(&listen_lock);
                        kfree(s);
                        return;
                }

                listen = listen->next;
        }
        spin_unlock_bh(&listen_lock);
}

EXPORT_SYMBOL(ax25_listen_release);

int (*ax25_protocol_function(unsigned int pid))(struct sk_buff *, ax25_cb *)
{
        int (*res)(struct sk_buff *, ax25_cb *) = NULL;
        struct ax25_protocol *protocol;

        read_lock(&protocol_list_lock);
        for (protocol = protocol_list; protocol != NULL; protocol = protocol->next)
                if (protocol->pid == pid) {
                        res = protocol->func;
                        break;
                }
        read_unlock(&protocol_list_lock);

        return res;
}

int ax25_listen_mine(ax25_address *callsign, struct net_device *dev)
{
        struct listen_struct *listen;

        spin_lock_bh(&listen_lock);
        for (listen = listen_list; listen != NULL; listen = listen->next)
                if (ax25cmp(&listen->callsign, callsign) == 0 &&
                    (listen->dev == dev || listen->dev == NULL)) {
                        spin_unlock_bh(&listen_lock);
                        return 1;
        }
        spin_unlock_bh(&listen_lock);

        return 0;
}

void ax25_link_failed(ax25_cb *ax25, int reason)
{
        struct ax25_linkfail *lf;
        struct hlist_node *node;

        spin_lock_bh(&linkfail_lock);
        hlist_for_each_entry(lf, node, &ax25_linkfail_list, lf_node)
                lf->func(ax25, reason);
        spin_unlock_bh(&linkfail_lock);
}

int ax25_protocol_is_registered(unsigned int pid)
{
        struct ax25_protocol *protocol;
        int res = 0;

        read_lock_bh(&protocol_list_lock);
        for (protocol = protocol_list; protocol != NULL; protocol = protocol->next)
                if (protocol->pid == pid) {
                        res = 1;
                        break;
                }
        read_unlock_bh(&protocol_list_lock);

        return res;
}