// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *
 * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
 */
#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/slab.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/timer.h>
#include <linux/string.h>
#include <linux/sockios.h>
#include <linux/net.h>
#include <linux/spinlock.h>
#include <net/ax25.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/if_arp.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <linux/uaccess.h>
#include <linux/fcntl.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/init.h>

ax25_dev *ax25_dev_list;
DEFINE_SPINLOCK(ax25_dev_lock);

ax25_dev *ax25_addr_ax25dev(ax25_address *addr)
{
        ax25_dev *ax25_dev, *res = NULL;

        spin_lock_bh(&ax25_dev_lock);
        for (ax25_dev = ax25_dev_list; ax25_dev != NULL; ax25_dev = ax25_dev->next)
                if (ax25cmp(addr, (ax25_address *)ax25_dev->dev->dev_addr) == 0) {
                        res = ax25_dev;
                }
        spin_unlock_bh(&ax25_dev_lock);

        return res;
}

/*
 *      This is called when an interface is brought up. These are
 *      reasonable defaults.
 */
void ax25_dev_device_up(struct net_device *dev)
{
        ax25_dev *ax25_dev;

        if ((ax25_dev = kzalloc(sizeof(*ax25_dev), GFP_ATOMIC)) == NULL) {
                printk(KERN_ERR "AX.25: ax25_dev_device_up - out of memory\n");
                return;
        }

        dev->ax25_ptr     = ax25_dev;
        ax25_dev->dev     = dev;
        dev_hold(dev);
        ax25_dev->forward = NULL;

        ax25_dev->values[AX25_VALUES_IPDEFMODE] = AX25_DEF_IPDEFMODE;
        ax25_dev->values[AX25_VALUES_AXDEFMODE] = AX25_DEF_AXDEFMODE;
        ax25_dev->values[AX25_VALUES_BACKOFF]   = AX25_DEF_BACKOFF;
        ax25_dev->values[AX25_VALUES_CONMODE]   = AX25_DEF_CONMODE;
        ax25_dev->values[AX25_VALUES_WINDOW]    = AX25_DEF_WINDOW;
        ax25_dev->values[AX25_VALUES_EWINDOW]   = AX25_DEF_EWINDOW;
        ax25_dev->values[AX25_VALUES_T1]        = AX25_DEF_T1;
        ax25_dev->values[AX25_VALUES_T2]        = AX25_DEF_T2;
        ax25_dev->values[AX25_VALUES_T3]        = AX25_DEF_T3;
        ax25_dev->values[AX25_VALUES_IDLE]      = AX25_DEF_IDLE;
        ax25_dev->values[AX25_VALUES_N2]        = AX25_DEF_N2;
        ax25_dev->values[AX25_VALUES_PACLEN]    = AX25_DEF_PACLEN;
        ax25_dev->values[AX25_VALUES_PROTOCOL]  = AX25_DEF_PROTOCOL;
        ax25_dev->values[AX25_VALUES_DS_TIMEOUT]= AX25_DEF_DS_TIMEOUT;

#if defined(CONFIG_AX25_DAMA_SLAVE) || defined(CONFIG_AX25_DAMA_MASTER)
        ax25_ds_setup_timer(ax25_dev);
#endif

        spin_lock_bh(&ax25_dev_lock);
        ax25_dev->next = ax25_dev_list;
        ax25_dev_list  = ax25_dev;
        spin_unlock_bh(&ax25_dev_lock);

        ax25_register_dev_sysctl(ax25_dev);
}

void ax25_dev_device_down(struct net_device *dev)
{
        ax25_dev *s, *ax25_dev;

        if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL)
                return;

        ax25_unregister_dev_sysctl(ax25_dev);

        spin_lock_bh(&ax25_dev_lock);

#ifdef CONFIG_AX25_DAMA_SLAVE
        ax25_ds_del_timer(ax25_dev);
#endif

        /*
         *      Remove any packet forwarding that points to this device.
         */
        for (s = ax25_dev_list; s != NULL; s = s->next)
                if (s->forward == dev)
                        s->forward = NULL;

        if ((s = ax25_dev_list) == ax25_dev) {
                ax25_dev_list = s->next;
                spin_unlock_bh(&ax25_dev_lock);
                dev->ax25_ptr = NULL;
                dev_put(dev);
                kfree(ax25_dev);
                return;
        }

        while (s != NULL && s->next != NULL) {
                if (s->next == ax25_dev) {
                        s->next = ax25_dev->next;
                        spin_unlock_bh(&ax25_dev_lock);
                        dev->ax25_ptr = NULL;
                        dev_put(dev);
                        kfree(ax25_dev);
                        return;
                }

                s = s->next;
        }
        spin_unlock_bh(&ax25_dev_lock);
        dev->ax25_ptr = NULL;
}

int ax25_fwd_ioctl(unsigned int cmd, struct ax25_fwd_struct *fwd)
{
        ax25_dev *ax25_dev, *fwd_dev;

        if ((ax25_dev = ax25_addr_ax25dev(&fwd->port_from)) == NULL)
                return -EINVAL;

        switch (cmd) {
        case SIOCAX25ADDFWD:
                if ((fwd_dev = ax25_addr_ax25dev(&fwd->port_to)) == NULL)
                        return -EINVAL;
                if (ax25_dev->forward != NULL)
                        return -EINVAL;
                ax25_dev->forward = fwd_dev->dev;
                break;

        case SIOCAX25DELFWD:
                if (ax25_dev->forward == NULL)
                        return -EINVAL;
                ax25_dev->forward = NULL;
                break;

        default:
                return -EINVAL;
        }

        return 0;
}

struct net_device *ax25_fwd_dev(struct net_device *dev)
{
        ax25_dev *ax25_dev;

        if ((ax25_dev = ax25_dev_ax25dev(dev)) == NULL)
                return dev;

        if (ax25_dev->forward == NULL)
                return dev;

        return ax25_dev->forward;
}

/*
 *      Free all memory associated with device structures.
 */
void __exit ax25_dev_free(void)
{
        ax25_dev *s, *ax25_dev;

        spin_lock_bh(&ax25_dev_lock);
        ax25_dev = ax25_dev_list;
        while (ax25_dev != NULL) {
                s        = ax25_dev;
                dev_put(ax25_dev->dev);
                ax25_dev = ax25_dev->next;
                kfree(s);
        }
        ax25_dev_list = NULL;
        spin_unlock_bh(&ax25_dev_lock);
}