1. 根目录:
2. net
3. rose
4. rose_dev.c

/*
 * 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/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/system.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 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 (!memcpy(dev->dev_addr, sa->sa_data, dev->addr_len))
		return 0;

	if (dev->flags & IFF_UP) {
		err = rose_add_loopback_node((rose_address *)dev->dev_addr);
		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;
}