rose_dev.c

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/*
 * 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 ([email protected])
 */
#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);

    *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_rebuild_header(struct sk_buff *skb)
{
#ifdef CONFIG_INET
    struct net_device *dev = skb->dev;
    struct net_device_stats *stats = &dev->stats;
    unsigned char *bp = (unsigned char *)skb->data;
    struct sk_buff *skbn;
    unsigned int len;

    if (arp_find(bp + 7, skb)) {
        return 1;
    }

    if ((skbn = skb_clone(skb, GFP_ATOMIC)) == NULL) {
        kfree_skb(skb);
        return 1;
    }

    if (skb->sk != NULL)
        skb_set_owner_w(skbn, skb->sk);

    kfree_skb(skb);

    len = skbn->len;

    if (!rose_route_frame(skbn, NULL)) {
        kfree_skb(skbn);
        stats->tx_errors++;
        return 1;
    }

    stats->tx_packets++;
    stats->tx_bytes += len;
#endif
    return 1;
}

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

    memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);

    return 0;
}

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

    err = rose_add_loopback_node((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((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;

    if (!netif_running(dev)) {
        printk(KERN_ERR "ROSE: rose_xmit - called when iface is down\n");
        return NETDEV_TX_BUSY;
    }
    dev_kfree_skb(skb);
    stats->tx_errors++;
    return NETDEV_TX_OK;
}

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