netconsole.c

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				 const char *buf,
				 size_t count)
{
	long remote_port;
#define __U16_MAX	((__u16) ~0U)

	if (nt->enabled) {
		printk(KERN_ERR "netconsole: target (%s) is enabled, "
				"disable to update parameters\n",
				config_item_name(&nt->item));
		return -EINVAL;
	}

	remote_port = strtol10_check_range(buf, 0, __U16_MAX);
	if (remote_port < 0)
		return remote_port;

	nt->np.remote_port = remote_port;

	return strnlen(buf, count);
}

static ssize_t store_local_ip(struct netconsole_target *nt,
			      const char *buf,
			      size_t count)
{
	if (nt->enabled) {
		printk(KERN_ERR "netconsole: target (%s) is enabled, "
				"disable to update parameters\n",
				config_item_name(&nt->item));
		return -EINVAL;
	}

	nt->np.local_ip = ntohl(in_aton(buf));

	return strnlen(buf, count);
}

static ssize_t store_remote_ip(struct netconsole_target *nt,
			       const char *buf,
			       size_t count)
{
	if (nt->enabled) {
		printk(KERN_ERR "netconsole: target (%s) is enabled, "
				"disable to update parameters\n",
				config_item_name(&nt->item));
		return -EINVAL;
	}

	nt->np.remote_ip = ntohl(in_aton(buf));

	return strnlen(buf, count);
}

static ssize_t store_remote_mac(struct netconsole_target *nt,
				const char *buf,
				size_t count)
{
	u8 remote_mac[ETH_ALEN];
	char *p = (char *) buf;
	int i;

	if (nt->enabled) {
		printk(KERN_ERR "netconsole: target (%s) is enabled, "
				"disable to update parameters\n",
				config_item_name(&nt->item));
		return -EINVAL;
	}

	for (i = 0; i < ETH_ALEN - 1; i++) {
		remote_mac[i] = simple_strtoul(p, &p, 16);
		if (*p != ':')
			goto invalid;
		p++;
	}
	remote_mac[ETH_ALEN - 1] = simple_strtoul(p, &p, 16);
	if (*p && (*p != '\n'))
		goto invalid;

	memcpy(nt->np.remote_mac, remote_mac, ETH_ALEN);

	return strnlen(buf, count);

invalid:
	printk(KERN_ERR "netconsole: invalid input\n");
	return -EINVAL;
}

/*
 * Attribute definitions for netconsole_target.
 */

#define NETCONSOLE_TARGET_ATTR_RO(_name)				\
static struct netconsole_target_attr netconsole_target_##_name =	\
	__CONFIGFS_ATTR(_name, S_IRUGO, show_##_name, NULL)

#define NETCONSOLE_TARGET_ATTR_RW(_name)				\
static struct netconsole_target_attr netconsole_target_##_name =	\
	__CONFIGFS_ATTR(_name, S_IRUGO | S_IWUSR, show_##_name, store_##_name)

NETCONSOLE_TARGET_ATTR_RW(enabled);
NETCONSOLE_TARGET_ATTR_RW(dev_name);
NETCONSOLE_TARGET_ATTR_RW(local_port);
NETCONSOLE_TARGET_ATTR_RW(remote_port);
NETCONSOLE_TARGET_ATTR_RW(local_ip);
NETCONSOLE_TARGET_ATTR_RW(remote_ip);
NETCONSOLE_TARGET_ATTR_RO(local_mac);
NETCONSOLE_TARGET_ATTR_RW(remote_mac);

static struct configfs_attribute *netconsole_target_attrs[] = {
	&netconsole_target_enabled.attr,
	&netconsole_target_dev_name.attr,
	&netconsole_target_local_port.attr,
	&netconsole_target_remote_port.attr,
	&netconsole_target_local_ip.attr,
	&netconsole_target_remote_ip.attr,
	&netconsole_target_local_mac.attr,
	&netconsole_target_remote_mac.attr,
	NULL,
};

/*
 * Item operations and type for netconsole_target.
 */

static void netconsole_target_release(struct config_item *item)
{
	kfree(to_target(item));
}

static ssize_t netconsole_target_attr_show(struct config_item *item,
					   struct configfs_attribute *attr,
					   char *buf)
{
	ssize_t ret = -EINVAL;
	struct netconsole_target *nt = to_target(item);
	struct netconsole_target_attr *na =
		container_of(attr, struct netconsole_target_attr, attr);

	if (na->show)
		ret = na->show(nt, buf);

	return ret;
}

static ssize_t netconsole_target_attr_store(struct config_item *item,
					    struct configfs_attribute *attr,
					    const char *buf,
					    size_t count)
{
	ssize_t ret = -EINVAL;
	struct netconsole_target *nt = to_target(item);
	struct netconsole_target_attr *na =
		container_of(attr, struct netconsole_target_attr, attr);

	if (na->store)
		ret = na->store(nt, buf, count);

	return ret;
}

static struct configfs_item_operations netconsole_target_item_ops = {
	.release		= netconsole_target_release,
	.show_attribute		= netconsole_target_attr_show,
	.store_attribute	= netconsole_target_attr_store,
};

static struct config_item_type netconsole_target_type = {
	.ct_attrs		= netconsole_target_attrs,
	.ct_item_ops		= &netconsole_target_item_ops,
	.ct_owner		= THIS_MODULE,
};

/*
 * Group operations and type for netconsole_subsys.
 */

static struct config_item *make_netconsole_target(struct config_group *group,
						  const char *name)
{
	unsigned long flags;
	struct netconsole_target *nt;

	/*
	 * Allocate and initialize with defaults.
	 * Target is disabled at creation (enabled == 0).
	 */
	nt = kzalloc(sizeof(*nt), GFP_KERNEL);
	if (!nt) {
		printk(KERN_ERR "netconsole: failed to allocate memory\n");
		return NULL;
	}

	nt->np.name = "netconsole";
	strlcpy(nt->np.dev_name, "eth0", IFNAMSIZ);
	nt->np.local_port = 6665;
	nt->np.remote_port = 6666;
	memset(nt->np.remote_mac, 0xff, ETH_ALEN);

	/* Initialize the config_item member */
	config_item_init_type_name(&nt->item, name, &netconsole_target_type);

	/* Adding, but it is disabled */
	spin_lock_irqsave(&target_list_lock, flags);
	list_add(&nt->list, &target_list);
	spin_unlock_irqrestore(&target_list_lock, flags);

	return &nt->item;
}

static void drop_netconsole_target(struct config_group *group,
				   struct config_item *item)
{
	unsigned long flags;
	struct netconsole_target *nt = to_target(item);

	spin_lock_irqsave(&target_list_lock, flags);
	list_del(&nt->list);
	spin_unlock_irqrestore(&target_list_lock, flags);

	/*
	 * The target may have never been enabled, or was manually disabled
	 * before being removed so netpoll may have already been cleaned up.
	 */
	if (nt->enabled)
		netpoll_cleanup(&nt->np);

	config_item_put(&nt->item);
}

static struct configfs_group_operations netconsole_subsys_group_ops = {
	.make_item	= make_netconsole_target,
	.drop_item	= drop_netconsole_target,
};

static struct config_item_type netconsole_subsys_type = {
	.ct_group_ops	= &netconsole_subsys_group_ops,
	.ct_owner	= THIS_MODULE,
};

/* The netconsole configfs subsystem */
static struct configfs_subsystem netconsole_subsys = {
	.su_group	= {
		.cg_item	= {
			.ci_namebuf	= "netconsole",
			.ci_type	= &netconsole_subsys_type,
		},
	},
};

#endif	/* CONFIG_NETCONSOLE_DYNAMIC */

/* Handle network interface device notifications */
static int netconsole_netdev_event(struct notifier_block *this,
				   unsigned long event,
				   void *ptr)
{
	unsigned long flags;
	struct netconsole_target *nt;
	struct net_device *dev = ptr;

	if (!(event == NETDEV_CHANGEADDR || event == NETDEV_CHANGENAME))
		goto done;

	spin_lock_irqsave(&target_list_lock, flags);
	list_for_each_entry(nt, &target_list, list) {
		netconsole_target_get(nt);
		if (nt->np.dev == dev) {
			switch (event) {
			case NETDEV_CHANGEADDR:
				memcpy(nt->np.local_mac, dev->dev_addr, ETH_ALEN);
				break;

			case NETDEV_CHANGENAME:
				strlcpy(nt->np.dev_name, dev->name, IFNAMSIZ);
				break;
			}
		}
		netconsole_target_put(nt);
	}
	spin_unlock_irqrestore(&target_list_lock, flags);

done:
	return NOTIFY_DONE;
}

static struct notifier_block netconsole_netdev_notifier = {
	.notifier_call  = netconsole_netdev_event,
};

static void write_msg(struct console *con, const char *msg, unsigned int len)
{
	int frag, left;
	unsigned long flags;
	struct netconsole_target *nt;
	const char *tmp;

	/* Avoid taking lock and disabling interrupts unnecessarily */
	if (list_empty(&target_list))
		return;

	spin_lock_irqsave(&target_list_lock, flags);
	list_for_each_entry(nt, &target_list, list) {
		netconsole_target_get(nt);
		if (nt->enabled && netif_running(nt->np.dev)) {
			/*
			 * We nest this inside the for-each-target loop above
			 * so that we're able to get as much logging out to
			 * at least one target if we die inside here, instead
			 * of unnecessarily keeping all targets in lock-step.
			 */
			tmp = msg;
			for (left = len; left;) {
				frag = min(left, MAX_PRINT_CHUNK);
				netpoll_send_udp(&nt->np, tmp, frag);
				tmp += frag;
				left -= frag;
			}
		}
		netconsole_target_put(nt);
	}
	spin_unlock_irqrestore(&target_list_lock, flags);
}

static struct console netconsole = {
	.name	= "netcon",
	.flags	= CON_ENABLED | CON_PRINTBUFFER,
	.write	= write_msg,
};

static int __init init_netconsole(void)
{
	int err;
	struct netconsole_target *nt, *tmp;
	unsigned long flags;
	char *target_config;
	char *input = config;

	if (strnlen(input, MAX_PARAM_LENGTH)) {
		while ((target_config = strsep(&input, ";"))) {
			nt = alloc_param_target(target_config);
			if (IS_ERR(nt)) {
				err = PTR_ERR(nt);
				goto fail;
			}
			spin_lock_irqsave(&target_list_lock, flags);
			list_add(&nt->list, &target_list);
			spin_unlock_irqrestore(&target_list_lock, flags);
		}
	}

	err = register_netdevice_notifier(&netconsole_netdev_notifier);
	if (err)
		goto fail;

	err = dynamic_netconsole_init();
	if (err)
		goto undonotifier;

	register_console(&netconsole);
	printk(KERN_INFO "netconsole: network logging started\n");

	return err;

undonotifier:
	unregister_netdevice_notifier(&netconsole_netdev_notifier);

fail:
	printk(KERN_ERR "netconsole: cleaning up\n");

	/*
	 * Remove all targets and destroy them (only targets created
	 * from the boot/module option exist here). Skipping the list
	 * lock is safe here, and netpoll_cleanup() will sleep.
	 */
	list_for_each_entry_safe(nt, tmp, &target_list, list) {
		list_del(&nt->list);
		free_param_target(nt);
	}

	return err;
}

static void __exit cleanup_netconsole(void)
{
	struct netconsole_target *nt, *tmp;

	unregister_console(&netconsole);
	dynamic_netconsole_exit();
	unregister_netdevice_notifier(&netconsole_netdev_notifier);

	/*
	 * Targets created via configfs pin references on our module
	 * and would first be rmdir(2)'ed from userspace. We reach
	 * here only when they are already destroyed, and only those
	 * created from the boot/module option are left, so remove and
	 * destroy them. Skipping the list lock is safe here, and
	 * netpoll_cleanup() will sleep.
	 */
	list_for_each_entry_safe(nt, tmp, &target_list, list) {
		list_del(&nt->list);
		free_param_target(nt);
	}
}

module_init(init_netconsole);
module_exit(cleanup_netconsole);