clip.c

linux 内核源代码

	int error;
	struct clip_vcc *clip_vcc;
	struct flowi fl = { .nl_u = { .ip4_u = { .daddr = ip, .tos = 1}} };
	struct rtable *rt;

	if (vcc->push != clip_push) {
		printk(KERN_WARNING "clip_setentry: non-CLIP VCC\n");
		return -EBADF;
	}
	clip_vcc = CLIP_VCC(vcc);
	if (!ip) {
		if (!clip_vcc->entry) {
			printk(KERN_ERR "hiding hidden ATMARP entry\n");
			return 0;
		}
		pr_debug("setentry: remove\n");
		unlink_clip_vcc(clip_vcc);
		return 0;
	}
	error = ip_route_output_key(&rt, &fl);
	if (error)
		return error;
	neigh = __neigh_lookup(&clip_tbl, &ip, rt->u.dst.dev, 1);
	ip_rt_put(rt);
	if (!neigh)
		return -ENOMEM;
	entry = NEIGH2ENTRY(neigh);
	if (entry != clip_vcc->entry) {
		if (!clip_vcc->entry)
			pr_debug("setentry: add\n");
		else {
			pr_debug("setentry: update\n");
			unlink_clip_vcc(clip_vcc);
		}
		link_vcc(clip_vcc, entry);
	}
	error = neigh_update(neigh, llc_oui, NUD_PERMANENT,
			     NEIGH_UPDATE_F_OVERRIDE | NEIGH_UPDATE_F_ADMIN);
	neigh_release(neigh);
	return error;
}

static void clip_setup(struct net_device *dev)
{
	dev->hard_start_xmit = clip_start_xmit;
	/* sg_xmit ... */
	dev->get_stats = clip_get_stats;
	dev->type = ARPHRD_ATM;
	dev->hard_header_len = RFC1483LLC_LEN;
	dev->mtu = RFC1626_MTU;
	dev->tx_queue_len = 100;	/* "normal" queue (packets) */
	/* When using a "real" qdisc, the qdisc determines the queue */
	/* length. tx_queue_len is only used for the default case, */
	/* without any more elaborate queuing. 100 is a reasonable */
	/* compromise between decent burst-tolerance and protection */
	/* against memory hogs. */
}

static int clip_create(int number)
{
	struct net_device *dev;
	struct clip_priv *clip_priv;
	int error;

	if (number != -1) {
		for (dev = clip_devs; dev; dev = PRIV(dev)->next)
			if (PRIV(dev)->number == number)
				return -EEXIST;
	} else {
		number = 0;
		for (dev = clip_devs; dev; dev = PRIV(dev)->next)
			if (PRIV(dev)->number >= number)
				number = PRIV(dev)->number + 1;
	}
	dev = alloc_netdev(sizeof(struct clip_priv), "", clip_setup);
	if (!dev)
		return -ENOMEM;
	clip_priv = PRIV(dev);
	sprintf(dev->name, "atm%d", number);
	spin_lock_init(&clip_priv->xoff_lock);
	clip_priv->number = number;
	error = register_netdev(dev);
	if (error) {
		free_netdev(dev);
		return error;
	}
	clip_priv->next = clip_devs;
	clip_devs = dev;
	pr_debug("registered (net:%s)\n", dev->name);
	return number;
}

static int clip_device_event(struct notifier_block *this, unsigned long event,
			     void *arg)
{
	struct net_device *dev = arg;

	if (dev->nd_net != &init_net)
		return NOTIFY_DONE;

	if (event == NETDEV_UNREGISTER) {
		neigh_ifdown(&clip_tbl, dev);
		return NOTIFY_DONE;
	}

	/* ignore non-CLIP devices */
	if (dev->type != ARPHRD_ATM || dev->hard_start_xmit != clip_start_xmit)
		return NOTIFY_DONE;

	switch (event) {
	case NETDEV_UP:
		pr_debug("clip_device_event NETDEV_UP\n");
		to_atmarpd(act_up, PRIV(dev)->number, 0);
		break;
	case NETDEV_GOING_DOWN:
		pr_debug("clip_device_event NETDEV_DOWN\n");
		to_atmarpd(act_down, PRIV(dev)->number, 0);
		break;
	case NETDEV_CHANGE:
	case NETDEV_CHANGEMTU:
		pr_debug("clip_device_event NETDEV_CHANGE*\n");
		to_atmarpd(act_change, PRIV(dev)->number, 0);
		break;
	}
	return NOTIFY_DONE;
}

static int clip_inet_event(struct notifier_block *this, unsigned long event,
			   void *ifa)
{
	struct in_device *in_dev;

	in_dev = ((struct in_ifaddr *)ifa)->ifa_dev;
	if (!in_dev || !in_dev->dev) {
		printk(KERN_WARNING "clip_inet_event: no device\n");
		return NOTIFY_DONE;
	}
	/*
	 * Transitions are of the down-change-up type, so it's sufficient to
	 * handle the change on up.
	 */
	if (event != NETDEV_UP)
		return NOTIFY_DONE;
	return clip_device_event(this, NETDEV_CHANGE, in_dev->dev);
}


static struct notifier_block clip_dev_notifier = {
	.notifier_call = clip_device_event,
};



static struct notifier_block clip_inet_notifier = {
	.notifier_call = clip_inet_event,
};



static void atmarpd_close(struct atm_vcc *vcc)
{
	pr_debug("atmarpd_close\n");

	rtnl_lock();
	atmarpd = NULL;
	skb_queue_purge(&sk_atm(vcc)->sk_receive_queue);
	rtnl_unlock();

	pr_debug("(done)\n");
	module_put(THIS_MODULE);
}


static struct atmdev_ops atmarpd_dev_ops = {
	.close = atmarpd_close
};


static struct atm_dev atmarpd_dev = {
	.ops =			&atmarpd_dev_ops,
	.type =			"arpd",
	.number = 		999,
	.lock =			__SPIN_LOCK_UNLOCKED(atmarpd_dev.lock)
};


static int atm_init_atmarp(struct atm_vcc *vcc)
{
	rtnl_lock();
	if (atmarpd) {
		rtnl_unlock();
		return -EADDRINUSE;
	}

	mod_timer(&idle_timer, jiffies+CLIP_CHECK_INTERVAL*HZ);

	atmarpd = vcc;
	set_bit(ATM_VF_META,&vcc->flags);
	set_bit(ATM_VF_READY,&vcc->flags);
	    /* allow replies and avoid getting closed if signaling dies */
	vcc->dev = &atmarpd_dev;
	vcc_insert_socket(sk_atm(vcc));
	vcc->push = NULL;
	vcc->pop = NULL; /* crash */
	vcc->push_oam = NULL; /* crash */
	rtnl_unlock();
	return 0;
}

static int clip_ioctl(struct socket *sock, unsigned int cmd, unsigned long arg)
{
	struct atm_vcc *vcc = ATM_SD(sock);
	int err = 0;

	switch (cmd) {
	case SIOCMKCLIP:
	case ATMARPD_CTRL:
	case ATMARP_MKIP:
	case ATMARP_SETENTRY:
	case ATMARP_ENCAP:
		if (!capable(CAP_NET_ADMIN))
			return -EPERM;
		break;
	default:
		return -ENOIOCTLCMD;
	}

	switch (cmd) {
	case SIOCMKCLIP:
		err = clip_create(arg);
		break;
	case ATMARPD_CTRL:
		err = atm_init_atmarp(vcc);
		if (!err) {
			sock->state = SS_CONNECTED;
			__module_get(THIS_MODULE);
		}
		break;
	case ATMARP_MKIP:
		err = clip_mkip(vcc, arg);
		break;
	case ATMARP_SETENTRY:
		err = clip_setentry(vcc, (__force __be32)arg);
		break;
	case ATMARP_ENCAP:
		err = clip_encap(vcc, arg);
		break;
	}
	return err;
}

static struct atm_ioctl clip_ioctl_ops = {
	.owner = THIS_MODULE,
	.ioctl = clip_ioctl,
};

#ifdef CONFIG_PROC_FS

static void svc_addr(struct seq_file *seq, struct sockaddr_atmsvc *addr)
{
	static int code[] = { 1, 2, 10, 6, 1, 0 };
	static int e164[] = { 1, 8, 4, 6, 1, 0 };

	if (*addr->sas_addr.pub) {
		seq_printf(seq, "%s", addr->sas_addr.pub);
		if (*addr->sas_addr.prv)
			seq_putc(seq, '+');
	} else if (!*addr->sas_addr.prv) {
		seq_printf(seq, "%s", "(none)");
		return;
	}
	if (*addr->sas_addr.prv) {
		unsigned char *prv = addr->sas_addr.prv;
		int *fields;
		int i, j;

		fields = *prv == ATM_AFI_E164 ? e164 : code;
		for (i = 0; fields[i]; i++) {
			for (j = fields[i]; j; j--)
				seq_printf(seq, "%02X", *prv++);
			if (fields[i + 1])
				seq_putc(seq, '.');
		}
	}
}

/* This means the neighbour entry has no attached VCC objects. */
#define SEQ_NO_VCC_TOKEN	((void *) 2)

static void atmarp_info(struct seq_file *seq, struct net_device *dev,
			struct atmarp_entry *entry, struct clip_vcc *clip_vcc)
{
	unsigned long exp;
	char buf[17];
	int svc, llc, off;

	svc = ((clip_vcc == SEQ_NO_VCC_TOKEN) ||
	       (sk_atm(clip_vcc->vcc)->sk_family == AF_ATMSVC));

	llc = ((clip_vcc == SEQ_NO_VCC_TOKEN) || clip_vcc->encap);

	if (clip_vcc == SEQ_NO_VCC_TOKEN)
		exp = entry->neigh->used;
	else
		exp = clip_vcc->last_use;

	exp = (jiffies - exp) / HZ;

	seq_printf(seq, "%-6s%-4s%-4s%5ld ",
		   dev->name, svc ? "SVC" : "PVC", llc ? "LLC" : "NULL", exp);

	off = scnprintf(buf, sizeof(buf) - 1, "%d.%d.%d.%d",
			NIPQUAD(entry->ip));
	while (off < 16)
		buf[off++] = ' ';
	buf[off] = '\0';
	seq_printf(seq, "%s", buf);

	if (clip_vcc == SEQ_NO_VCC_TOKEN) {
		if (time_before(jiffies, entry->expires))
			seq_printf(seq, "(resolving)\n");
		else
			seq_printf(seq, "(expired, ref %d)\n",
				   atomic_read(&entry->neigh->refcnt));
	} else if (!svc) {
		seq_printf(seq, "%d.%d.%d\n",
			   clip_vcc->vcc->dev->number,
			   clip_vcc->vcc->vpi, clip_vcc->vcc->vci);
	} else {
		svc_addr(seq, &clip_vcc->vcc->remote);
		seq_putc(seq, '\n');
	}
}

struct clip_seq_state {
	/* This member must be first. */
	struct neigh_seq_state ns;

	/* Local to clip specific iteration. */
	struct clip_vcc *vcc;
};

static struct clip_vcc *clip_seq_next_vcc(struct atmarp_entry *e,
					  struct clip_vcc *curr)
{
	if (!curr) {
		curr = e->vccs;
		if (!curr)
			return SEQ_NO_VCC_TOKEN;
		return curr;
	}
	if (curr == SEQ_NO_VCC_TOKEN)
		return NULL;

	curr = curr->next;

	return curr;
}

static void *clip_seq_vcc_walk(struct clip_seq_state *state,
			       struct atmarp_entry *e, loff_t * pos)
{
	struct clip_vcc *vcc = state->vcc;

	vcc = clip_seq_next_vcc(e, vcc);
	if (vcc && pos != NULL) {
		while (*pos) {
			vcc = clip_seq_next_vcc(e, vcc);
			if (!vcc)
				break;
			--(*pos);
		}
	}
	state->vcc = vcc;

	return vcc;
}

static void *clip_seq_sub_iter(struct neigh_seq_state *_state,
			       struct neighbour *n, loff_t * pos)
{
	struct clip_seq_state *state = (struct clip_seq_state *)_state;

	return clip_seq_vcc_walk(state, NEIGH2ENTRY(n), pos);
}

static void *clip_seq_start(struct seq_file *seq, loff_t * pos)
{
	return neigh_seq_start(seq, pos, &clip_tbl, NEIGH_SEQ_NEIGH_ONLY);
}

static int clip_seq_show(struct seq_file *seq, void *v)
{
	static char atm_arp_banner[] =
	    "IPitf TypeEncp Idle IP address      ATM address\n";

	if (v == SEQ_START_TOKEN) {
		seq_puts(seq, atm_arp_banner);
	} else {
		struct clip_seq_state *state = seq->private;
		struct neighbour *n = v;
		struct clip_vcc *vcc = state->vcc;

		atmarp_info(seq, n->dev, NEIGH2ENTRY(n), vcc);
	}
	return 0;
}

static const struct seq_operations arp_seq_ops = {
	.start	= clip_seq_start,
	.next	= neigh_seq_next,
	.stop	= neigh_seq_stop,
	.show	= clip_seq_show,
};

static int arp_seq_open(struct inode *inode, struct file *file)
{
	struct clip_seq_state *state;
	struct seq_file *seq;
	int rc = -EAGAIN;

	state = kzalloc(sizeof(*state), GFP_KERNEL);
	if (!state) {
		rc = -ENOMEM;
		goto out_kfree;
	}
	state->ns.neigh_sub_iter = clip_seq_sub_iter;

	rc = seq_open(file, &arp_seq_ops);
	if (rc)
		goto out_kfree;

	seq = file->private_data;
	seq->private = state;
out:
	return rc;

out_kfree:
	kfree(state);
	goto out;
}

static const struct file_operations arp_seq_fops = {
	.open		= arp_seq_open,
	.read		= seq_read,
	.llseek		= seq_lseek,
	.release	= seq_release_private,
	.owner		= THIS_MODULE
};
#endif

static int __init atm_clip_init(void)
{
	neigh_table_init_no_netlink(&clip_tbl);

	clip_tbl_hook = &clip_tbl;
	register_atm_ioctl(&clip_ioctl_ops);
	register_netdevice_notifier(&clip_dev_notifier);
	register_inetaddr_notifier(&clip_inet_notifier);

	setup_timer(&idle_timer, idle_timer_check, 0);

#ifdef CONFIG_PROC_FS
	{
		struct proc_dir_entry *p;

		p = create_proc_entry("arp", S_IRUGO, atm_proc_root);
		if (p)
			p->proc_fops = &arp_seq_fops;
	}
#endif

	return 0;
}

static void __exit atm_clip_exit(void)
{
	struct net_device *dev, *next;

	remove_proc_entry("arp", atm_proc_root);

	unregister_inetaddr_notifier(&clip_inet_notifier);
	unregister_netdevice_notifier(&clip_dev_notifier);

	deregister_atm_ioctl(&clip_ioctl_ops);

	/* First, stop the idle timer, so it stops banging
	 * on the table.
	 */
	del_timer_sync(&idle_timer);

	/* Next, purge the table, so that the device
	 * unregister loop below does not hang due to
	 * device references remaining in the table.
	 */
	neigh_ifdown(&clip_tbl, NULL);

	dev = clip_devs;
	while (dev) {
		next = PRIV(dev)->next;
		unregister_netdev(dev);
		free_netdev(dev);
		dev = next;
	}

	/* Now it is safe to fully shutdown whole table. */
	neigh_table_clear(&clip_tbl);

	clip_tbl_hook = NULL;
}

module_init(atm_clip_init);
module_exit(atm_clip_exit);
MODULE_AUTHOR("Werner Almesberger");
MODULE_DESCRIPTION("Classical/IP over ATM interface");
MODULE_LICENSE("GPL");