// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *
 * Copyright (C) Jonathan Naylor G4KLX (g4klx@g4klx.demon.co.uk)
 */
#include <linux/module.h>
#include <linux/proc_fs.h>
#include <linux/kernel.h>
#include <linux/interrupt.h>
#include <linux/fs.h>
#include <linux/types.h>
#include <linux/sysctl.h>
#include <linux/string.h>
#include <linux/socket.h>
#include <linux/errno.h>
#include <linux/fcntl.h>
#include <linux/in.h>
#include <linux/if_ether.h>
#include <linux/slab.h>

#include <asm/io.h>

#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/if_arp.h>
#include <linux/skbuff.h>

#include <net/ip.h>
#include <net/arp.h>

#include <net/ax25.h>
#include <net/rose.h>

static int rose_header(struct sk_buff *skb, struct net_device *dev,
                       unsigned short type,
                       const void *daddr, const void *saddr, unsigned int len)
{
        unsigned char *buff = skb_push(skb, ROSE_MIN_LEN + 2);

        if (daddr)
                memcpy(buff + 7, daddr, dev->addr_len);

        *buff++ = ROSE_GFI | ROSE_Q_BIT;
        *buff++ = 0x00;
        *buff++ = ROSE_DATA;
        *buff++ = 0x7F;
        *buff++ = AX25_P_IP;

        if (daddr != NULL)
                return 37;

        return -37;
}

static int rose_set_mac_address(struct net_device *dev, void *addr)
{
        struct sockaddr *sa = addr;
        int err;

        if (!memcmp(dev->dev_addr, sa->sa_data, dev->addr_len))
                return 0;

        if (dev->flags & IFF_UP) {
                err = rose_add_loopback_node((rose_address *)sa->sa_data);
                if (err)
                        return err;

                rose_del_loopback_node((const rose_address *)dev->dev_addr);
        }

        dev_addr_set(dev, sa->sa_data);

        return 0;
}

static int rose_open(struct net_device *dev)
{
        int err;

        err = rose_add_loopback_node((const rose_address *)dev->dev_addr);
        if (err)
                return err;

        netif_start_queue(dev);

        return 0;
}

static int rose_close(struct net_device *dev)
{
        netif_stop_queue(dev);
        rose_del_loopback_node((const rose_address *)dev->dev_addr);
        return 0;
}

static netdev_tx_t rose_xmit(struct sk_buff *skb, struct net_device *dev)
{
        struct net_device_stats *stats = &dev->stats;
        unsigned int len = skb->len;

        if (!netif_running(dev)) {
                printk(KERN_ERR "ROSE: rose_xmit - called when iface is down\n");
                return NETDEV_TX_BUSY;
        }

        if (!rose_route_frame(skb, NULL)) {
                dev_kfree_skb(skb);
                stats->tx_errors++;
                return NETDEV_TX_OK;
        }

        stats->tx_packets++;
        stats->tx_bytes += len;
        return NETDEV_TX_OK;
}

static const struct header_ops rose_header_ops = {
        .create = rose_header,
};

static const struct net_device_ops rose_netdev_ops = {
        .ndo_open               = rose_open,
        .ndo_stop               = rose_close,
        .ndo_start_xmit         = rose_xmit,
        .ndo_set_mac_address    = rose_set_mac_address,
};

void rose_setup(struct net_device *dev)
{
        dev->mtu                = ROSE_MAX_PACKET_SIZE - 2;
        dev->netdev_ops         = &rose_netdev_ops;

        dev->header_ops         = &rose_header_ops;
        dev->hard_header_len    = AX25_BPQ_HEADER_LEN + AX25_MAX_HEADER_LEN + ROSE_MIN_LEN;
        dev->addr_len           = ROSE_ADDR_LEN;
        dev->type               = ARPHRD_ROSE;

        /* New-style flags. */
        dev->flags              = IFF_NOARP;
}