// SPDX-License-Identifier: GPL-2.0-or-later

  /*

   * Copyright (c) 2003 Evgeniy Polyakov <zbr@ioremap.net>

   */

  #include <linux/slab.h>

  #include <linux/skbuff.h>
  #include <linux/netlink.h>

  #include <linux/connector.h>

  #include "w1_internal.h"

  #include "w1_netlink.h"

  #if defined(CONFIG_W1_CON) && (defined(CONFIG_CONNECTOR) || (defined(CONFIG_CONNECTOR_MODULE) && defined(CONFIG_W1_MODULE)))

  /* Bundle together everything required to process a request in one memory
   * allocation.
   */
  struct w1_cb_block {
  	atomic_t refcnt;
  	u32 portid; /* Sending process port ID */
  	/* maximum value for first_cn->len */
  	u16 maxlen;
  	/* pointers to building up the reply message */
  	struct cn_msg *first_cn; /* fixed once the structure is populated */
  	struct cn_msg *cn; /* advances as cn_msg is appeneded */
  	struct w1_netlink_msg *msg; /* advances as w1_netlink_msg is appened */
  	struct w1_netlink_cmd *cmd; /* advances as cmds are appened */
  	struct w1_netlink_msg *cur_msg; /* currently message being processed */
  	/* copy of the original request follows */
  	struct cn_msg request_cn;
  	/* followed by variable length:
  	 * cn_msg, data (w1_netlink_msg and w1_netlink_cmd)
  	 * one or more struct w1_cb_node
  	 * reply first_cn, data (w1_netlink_msg and w1_netlink_cmd)
  	 */
  };
  struct w1_cb_node {
  	struct w1_async_cmd async;
  	/* pointers within w1_cb_block and cn data */
  	struct w1_cb_block *block;
  	struct w1_netlink_msg *msg;
  	struct w1_slave *sl;
  	struct w1_master *dev;
  };
  
  /**
   * w1_reply_len() - calculate current reply length, compare to maxlen
   * @block: block to calculate
   *
   * Calculates the current message length including possible multiple
   * cn_msg and data, excludes the first sizeof(struct cn_msg).  Direclty
   * compariable to maxlen and usable to send the message.
   */
  static u16 w1_reply_len(struct w1_cb_block *block)
  {
  	if (!block->cn)
  		return 0;
  	return (u8 *)block->cn - (u8 *)block->first_cn + block->cn->len;
  }
  
  static void w1_unref_block(struct w1_cb_block *block)
  {
  	if (atomic_sub_return(1, &block->refcnt) == 0) {
  		u16 len = w1_reply_len(block);
  		if (len) {
  			cn_netlink_send_mult(block->first_cn, len,
  				block->portid, 0, GFP_KERNEL);
  		}
  		kfree(block);
  	}
  }
  
  /**
   * w1_reply_make_space() - send message if needed to make space
   * @block: block to make space on
   * @space: how many bytes requested
   *
   * Verify there is enough room left for the caller to add "space" bytes to the
   * message, if there isn't send the message and reset.
   */
  static void w1_reply_make_space(struct w1_cb_block *block, u16 space)
  {
  	u16 len = w1_reply_len(block);
  	if (len + space >= block->maxlen) {
  		cn_netlink_send_mult(block->first_cn, len, block->portid, 0, GFP_KERNEL);
  		block->first_cn->len = 0;
  		block->cn = NULL;
  		block->msg = NULL;
  		block->cmd = NULL;
  	}
  }
  
  /* Early send when replies aren't bundled. */
  static void w1_netlink_check_send(struct w1_cb_block *block)
  {
  	if (!(block->request_cn.flags & W1_CN_BUNDLE) && block->cn)
  		w1_reply_make_space(block, block->maxlen);
  }
  
  /**
   * w1_netlink_setup_msg() - prepare to write block->msg
   * @block: block to operate on
   * @ack: determines if cn can be reused
   *
   * block->cn will be setup with the correct ack, advancing if needed
   * block->cn->len does not include space for block->msg
   * block->msg advances but remains uninitialized
   */
  static void w1_netlink_setup_msg(struct w1_cb_block *block, u32 ack)
  {
  	if (block->cn && block->cn->ack == ack) {
  		block->msg = (struct w1_netlink_msg *)(block->cn->data + block->cn->len);
  	} else {
  		/* advance or set to data */
  		if (block->cn)
  			block->cn = (struct cn_msg *)(block->cn->data +
  				block->cn->len);
  		else
  			block->cn = block->first_cn;
  
  		memcpy(block->cn, &block->request_cn, sizeof(*block->cn));
  		block->cn->len = 0;
  		block->cn->ack = ack;
  		block->msg = (struct w1_netlink_msg *)block->cn->data;
  	}
  }
  
  /* Append cmd to msg, include cmd->data as well.  This is because
   * any following data goes with the command and in the case of a read is
   * the results.
   */
  static void w1_netlink_queue_cmd(struct w1_cb_block *block,
  	struct w1_netlink_cmd *cmd)
  {
  	u32 space;
  	w1_reply_make_space(block, sizeof(struct cn_msg) +
  		sizeof(struct w1_netlink_msg) + sizeof(*cmd) + cmd->len);
  
  	/* There's a status message sent after each command, so no point
  	 * in trying to bundle this cmd after an existing one, because
  	 * there won't be one.  Allocate and copy over a new cn_msg.
  	 */
  	w1_netlink_setup_msg(block, block->request_cn.seq + 1);
  	memcpy(block->msg, block->cur_msg, sizeof(*block->msg));
  	block->cn->len += sizeof(*block->msg);
  	block->msg->len = 0;
  	block->cmd = (struct w1_netlink_cmd *)(block->msg->data);
  
  	space = sizeof(*cmd) + cmd->len;
  	if (block->cmd != cmd)
  		memcpy(block->cmd, cmd, space);
  	block->cn->len += space;
  	block->msg->len += space;
  }
  
  /* Append req_msg and req_cmd, no other commands and no data from req_cmd are
   * copied.
   */
  static void w1_netlink_queue_status(struct w1_cb_block *block,
  	struct w1_netlink_msg *req_msg, struct w1_netlink_cmd *req_cmd,
  	int error)

  {

  	u16 space = sizeof(struct cn_msg) + sizeof(*req_msg) + sizeof(*req_cmd);
  	w1_reply_make_space(block, space);
  	w1_netlink_setup_msg(block, block->request_cn.ack);
  
  	memcpy(block->msg, req_msg, sizeof(*req_msg));
  	block->cn->len += sizeof(*req_msg);
  	block->msg->len = 0;
  	block->msg->status = (u8)-error;
  	if (req_cmd) {
  		struct w1_netlink_cmd *cmd = (struct w1_netlink_cmd *)block->msg->data;
  		memcpy(cmd, req_cmd, sizeof(*cmd));
  		block->cn->len += sizeof(*cmd);
  		block->msg->len += sizeof(*cmd);
  		cmd->len = 0;
  	}
  	w1_netlink_check_send(block);
  }

  /**
   * w1_netlink_send_error() - sends the error message now
   * @cn: original cn_msg
   * @msg: original w1_netlink_msg
   * @portid: where to send it
   * @error: error status
   *
   * Use when a block isn't available to queue the message to and cn, msg
   * might not be contiguous.
   */
  static void w1_netlink_send_error(struct cn_msg *cn, struct w1_netlink_msg *msg,
  	int portid, int error)
  {
  	struct {
  		struct cn_msg cn;
  		struct w1_netlink_msg msg;
  	} packet;
  	memcpy(&packet.cn, cn, sizeof(packet.cn));
  	memcpy(&packet.msg, msg, sizeof(packet.msg));
  	packet.cn.len = sizeof(packet.msg);
  	packet.msg.len = 0;
  	packet.msg.status = (u8)-error;
  	cn_netlink_send(&packet.cn, portid, 0, GFP_KERNEL);
  }
  
  /**
   * w1_netlink_send() - sends w1 netlink notifications
   * @dev: w1_master the even is associated with or for
   * @msg: w1_netlink_msg message to be sent
   *
   * This are notifications generated from the kernel.
   */
  void w1_netlink_send(struct w1_master *dev, struct w1_netlink_msg *msg)
  {
  	struct {
  		struct cn_msg cn;
  		struct w1_netlink_msg msg;
  	} packet;
  	memset(&packet, 0, sizeof(packet));

  	packet.cn.id.idx = CN_W1_IDX;
  	packet.cn.id.val = CN_W1_VAL;

  	packet.cn.seq = dev->seq++;
  	packet.cn.len = sizeof(*msg);

  	memcpy(&packet.msg, msg, sizeof(*msg));
  	packet.msg.len = 0;

  	cn_netlink_send(&packet.cn, 0, 0, GFP_KERNEL);

  }

  static void w1_send_slave(struct w1_master *dev, u64 rn)
  {

  	struct w1_cb_block *block = dev->priv;
  	struct w1_netlink_cmd *cache_cmd = block->cmd;

  	u64 *data;

  	w1_reply_make_space(block, sizeof(*data));

  	/* Add cmd back if the packet was sent */
  	if (!block->cmd) {
  		cache_cmd->len = 0;
  		w1_netlink_queue_cmd(block, cache_cmd);

  	}

  	data = (u64 *)(block->cmd->data + block->cmd->len);

  	*data = rn;

  	block->cn->len += sizeof(*data);
  	block->msg->len += sizeof(*data);
  	block->cmd->len += sizeof(*data);

  }

  static void w1_found_send_slave(struct w1_master *dev, u64 rn)

  {

  	/* update kernel slave list */
  	w1_slave_found(dev, rn);

  	w1_send_slave(dev, rn);
  }
  
  /* Get the current slave list, or search (with or without alarm) */

  static int w1_get_slaves(struct w1_master *dev, struct w1_netlink_cmd *req_cmd)

  {

  	struct w1_slave *sl;

  	req_cmd->len = 0;
  	w1_netlink_queue_cmd(dev->priv, req_cmd);

  
  	if (req_cmd->cmd == W1_CMD_LIST_SLAVES) {

  		u64 rn;

  		mutex_lock(&dev->list_mutex);

  		list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
  			memcpy(&rn, &sl->reg_num, sizeof(rn));
  			w1_send_slave(dev, rn);
  		}

  		mutex_unlock(&dev->list_mutex);

  	} else {

  		w1_search_process_cb(dev, req_cmd->cmd == W1_CMD_ALARM_SEARCH ?

  			W1_ALARM_SEARCH : W1_SEARCH, w1_found_send_slave);
  	}

  	return 0;

  }

  static int w1_process_command_io(struct w1_master *dev,
  	struct w1_netlink_cmd *cmd)

  {
  	int err = 0;

  	switch (cmd->cmd) {
  	case W1_CMD_TOUCH:
  		w1_touch_block(dev, cmd->data, cmd->len);

  		w1_netlink_queue_cmd(dev->priv, cmd);

  		break;
  	case W1_CMD_READ:
  		w1_read_block(dev, cmd->data, cmd->len);

  		w1_netlink_queue_cmd(dev->priv, cmd);

  		break;
  	case W1_CMD_WRITE:
  		w1_write_block(dev, cmd->data, cmd->len);
  		break;
  	default:

  		err = -EINVAL;

  		break;
  	}
  
  	return err;
  }

  static int w1_process_command_addremove(struct w1_master *dev,

  	struct w1_netlink_cmd *cmd)

  {

  	struct w1_slave *sl;
  	int err = 0;
  	struct w1_reg_num *id;

  	if (cmd->len != sizeof(*id))

  		return -EINVAL;

  	id = (struct w1_reg_num *)cmd->data;

  	sl = w1_slave_search_device(dev, id);
  	switch (cmd->cmd) {
  	case W1_CMD_SLAVE_ADD:
  		if (sl)
  			err = -EINVAL;
  		else
  			err = w1_attach_slave_device(dev, id);
  		break;
  	case W1_CMD_SLAVE_REMOVE:
  		if (sl)
  			w1_slave_detach(sl);
  		else
  			err = -EINVAL;
  		break;
  	default:
  		err = -EINVAL;
  		break;
  	}

  	return err;
  }

  static int w1_process_command_master(struct w1_master *dev,

  	struct w1_netlink_cmd *req_cmd)
  {
  	int err = -EINVAL;

  	/* drop bus_mutex for search (does it's own locking), and add/remove
  	 * which doesn't use the bus
  	 */

  	switch (req_cmd->cmd) {

  	case W1_CMD_SEARCH:
  	case W1_CMD_ALARM_SEARCH:

  	case W1_CMD_LIST_SLAVES:

  		mutex_unlock(&dev->bus_mutex);

  		err = w1_get_slaves(dev, req_cmd);

  		mutex_lock(&dev->bus_mutex);

  		break;
  	case W1_CMD_READ:
  	case W1_CMD_WRITE:
  	case W1_CMD_TOUCH:

  		err = w1_process_command_io(dev, req_cmd);

  		break;

  	case W1_CMD_RESET:
  		err = w1_reset_bus(dev);
  		break;

  	case W1_CMD_SLAVE_ADD:
  	case W1_CMD_SLAVE_REMOVE:

  		mutex_unlock(&dev->bus_mutex);
  		mutex_lock(&dev->mutex);

  		err = w1_process_command_addremove(dev, req_cmd);

  		mutex_unlock(&dev->mutex);
  		mutex_lock(&dev->bus_mutex);

  		break;

  	default:

  		err = -EINVAL;

  		break;

  	}

  	return err;
  }

  static int w1_process_command_slave(struct w1_slave *sl,
  		struct w1_netlink_cmd *cmd)

  {
  	dev_dbg(&sl->master->dev, "%s: %02x.%012llx.%02x: cmd=%02x, len=%u.
  ",
  		__func__, sl->reg_num.family, (unsigned long long)sl->reg_num.id,
  		sl->reg_num.crc, cmd->cmd, cmd->len);

  	return w1_process_command_io(sl->master, cmd);

  }

  static int w1_process_command_root(struct cn_msg *req_cn, u32 portid)

  {

  	struct w1_master *dev;

  	struct cn_msg *cn;

  	struct w1_netlink_msg *msg;

  	u32 *id;

  	cn = kmalloc(PAGE_SIZE, GFP_KERNEL);
  	if (!cn)
  		return -ENOMEM;
  
  	cn->id.idx = CN_W1_IDX;
  	cn->id.val = CN_W1_VAL;

  	cn->seq = req_cn->seq;
  	cn->ack = req_cn->seq + 1;

  	cn->len = sizeof(struct w1_netlink_msg);

  	msg = (struct w1_netlink_msg *)cn->data;

  	msg->type = W1_LIST_MASTERS;
  	msg->status = 0;
  	msg->len = 0;
  	id = (u32 *)msg->data;

  
  	mutex_lock(&w1_mlock);

  	list_for_each_entry(dev, &w1_masters, w1_master_entry) {

  		if (cn->len + sizeof(*id) > PAGE_SIZE - sizeof(struct cn_msg)) {

  			cn_netlink_send(cn, portid, 0, GFP_KERNEL);

  			cn->len = sizeof(struct w1_netlink_msg);

  			msg->len = 0;
  			id = (u32 *)msg->data;

  		}

  		*id = dev->id;
  		msg->len += sizeof(*id);

  		cn->len += sizeof(*id);
  		id++;
  	}

  	cn_netlink_send(cn, portid, 0, GFP_KERNEL);

  	mutex_unlock(&w1_mlock);
  
  	kfree(cn);
  	return 0;
  }

  static void w1_process_cb(struct w1_master *dev, struct w1_async_cmd *async_cmd)
  {
  	struct w1_cb_node *node = container_of(async_cmd, struct w1_cb_node,
  		async);

  	u16 mlen = node->msg->len;
  	u16 len;

  	int err = 0;
  	struct w1_slave *sl = node->sl;

  	struct w1_netlink_cmd *cmd = (struct w1_netlink_cmd *)node->msg->data;

  	mutex_lock(&dev->bus_mutex);

  	dev->priv = node->block;

  	if (sl && w1_reset_select_slave(sl))
  		err = -ENODEV;

  	node->block->cur_msg = node->msg;

  
  	while (mlen && !err) {

  		if (cmd->len + sizeof(struct w1_netlink_cmd) > mlen) {
  			err = -E2BIG;
  			break;
  		}
  
  		if (sl)

  			err = w1_process_command_slave(sl, cmd);

  		else

  			err = w1_process_command_master(dev, cmd);
  		w1_netlink_check_send(node->block);

  		w1_netlink_queue_status(node->block, node->msg, cmd, err);

  		err = 0;

  		len = sizeof(*cmd) + cmd->len;
  		cmd = (struct w1_netlink_cmd *)((u8 *)cmd + len);
  		mlen -= len;

  	}
  
  	if (!cmd || err)

  		w1_netlink_queue_status(node->block, node->msg, cmd, err);

  	/* ref taken in w1_search_slave or w1_search_master_id when building
  	 * the block
  	 */

  	if (sl)
  		w1_unref_slave(sl);
  	else
  		atomic_dec(&dev->refcnt);

  	dev->priv = NULL;

  	mutex_unlock(&dev->bus_mutex);

  
  	mutex_lock(&dev->list_mutex);
  	list_del(&async_cmd->async_entry);
  	mutex_unlock(&dev->list_mutex);

  	w1_unref_block(node->block);
  }
  
  static void w1_list_count_cmds(struct w1_netlink_msg *msg, int *cmd_count,
  	u16 *slave_len)
  {
  	struct w1_netlink_cmd *cmd = (struct w1_netlink_cmd *)msg->data;
  	u16 mlen = msg->len;
  	u16 len;
  	int slave_list = 0;
  	while (mlen) {
  		if (cmd->len + sizeof(struct w1_netlink_cmd) > mlen)
  			break;
  
  		switch (cmd->cmd) {
  		case W1_CMD_SEARCH:
  		case W1_CMD_ALARM_SEARCH:
  		case W1_CMD_LIST_SLAVES:
  			++slave_list;
  		}
  		++*cmd_count;
  		len = sizeof(*cmd) + cmd->len;
  		cmd = (struct w1_netlink_cmd *)((u8 *)cmd + len);
  		mlen -= len;
  	}
  
  	if (slave_list) {
  		struct w1_master *dev = w1_search_master_id(msg->id.mst.id);
  		if (dev) {
  			/* Bytes, and likely an overstimate, and if it isn't
  			 * the results can still be split between packets.
  			 */
  			*slave_len += sizeof(struct w1_reg_num) * slave_list *
  				(dev->slave_count + dev->max_slave_count);
  			/* search incremented it */
  			atomic_dec(&dev->refcnt);
  		}
  	}

  }

  static void w1_cn_callback(struct cn_msg *cn, struct netlink_skb_parms *nsp)

  {

  	struct w1_netlink_msg *msg = (struct w1_netlink_msg *)(cn + 1);

  	struct w1_slave *sl;
  	struct w1_master *dev;

  	u16 msg_len;

  	u16 slave_len = 0;

  	int err = 0;

  	struct w1_cb_block *block = NULL;
  	struct w1_cb_node *node = NULL;
  	int node_count = 0;

  	int cmd_count = 0;
  
  	/* If any unknown flag is set let the application know, that way
  	 * applications can detect the absence of features in kernels that
  	 * don't know about them.  http://lwn.net/Articles/587527/
  	 */
  	if (cn->flags & ~(W1_CN_BUNDLE)) {
  		w1_netlink_send_error(cn, msg, nsp->portid, -EINVAL);
  		return;
  	}

  
  	/* Count the number of master or slave commands there are to allocate
  	 * space for one cb_node each.
  	 */

  	msg_len = cn->len;

  	while (msg_len && !err) {

  		if (msg->len + sizeof(struct w1_netlink_msg) > msg_len) {

  			err = -E2BIG;
  			break;
  		}

  		/* count messages for nodes and allocate any additional space
  		 * required for slave lists
  		 */
  		if (msg->type == W1_MASTER_CMD || msg->type == W1_SLAVE_CMD) {

  			++node_count;

  			w1_list_count_cmds(msg, &cmd_count, &slave_len);
  		}

  		msg_len -= sizeof(struct w1_netlink_msg) + msg->len;
  		msg = (struct w1_netlink_msg *)(((u8 *)msg) +
  			sizeof(struct w1_netlink_msg) + msg->len);

  	}

  	msg = (struct w1_netlink_msg *)(cn + 1);

  	if (node_count) {

  		int size;

  		int reply_size = sizeof(*cn) + cn->len + slave_len;

  		if (cn->flags & W1_CN_BUNDLE) {
  			/* bundling duplicats some of the messages */
  			reply_size += 2 * cmd_count * (sizeof(struct cn_msg) +
  				sizeof(struct w1_netlink_msg) +
  				sizeof(struct w1_netlink_cmd));
  		}

  		reply_size = min(CONNECTOR_MAX_MSG_SIZE, reply_size);

  
  		/* allocate space for the block, a copy of the original message,
  		 * one node per cmd to point into the original message,
  		 * space for replies which is the original message size plus
  		 * space for any list slave data and status messages
  		 * cn->len doesn't include itself which is part of the block
  		 * */
  		size =  /* block + original message */
  			sizeof(struct w1_cb_block) + sizeof(*cn) + cn->len +
  			/* space for nodes */
  			node_count * sizeof(struct w1_cb_node) +
  			/* replies */
  			sizeof(struct cn_msg) + reply_size;
  		block = kzalloc(size, GFP_KERNEL);

  		if (!block) {

  			/* if the system is already out of memory,
  			 * (A) will this work, and (B) would it be better
  			 * to not try?
  			 */
  			w1_netlink_send_error(cn, msg, nsp->portid, -ENOMEM);

  			return;
  		}
  		atomic_set(&block->refcnt, 1);

  		block->portid = nsp->portid;

  		memcpy(&block->request_cn, cn, sizeof(*cn) + cn->len);
  		node = (struct w1_cb_node *)(block->request_cn.data + cn->len);
  
  		/* Sneeky, when not bundling, reply_size is the allocated space
  		 * required for the reply, cn_msg isn't part of maxlen so
  		 * it should be reply_size - sizeof(struct cn_msg), however
  		 * when checking if there is enough space, w1_reply_make_space
  		 * is called with the full message size including cn_msg,
  		 * because it isn't known at that time if an additional cn_msg
  		 * will need to be allocated.  So an extra cn_msg is added
  		 * above in "size".
  		 */
  		block->maxlen = reply_size;
  		block->first_cn = (struct cn_msg *)(node + node_count);
  		memset(block->first_cn, 0, sizeof(*block->first_cn));

  	}

  	msg_len = cn->len;

  	while (msg_len && !err) {

  
  		dev = NULL;
  		sl = NULL;

  		if (msg->len + sizeof(struct w1_netlink_msg) > msg_len) {

  			err = -E2BIG;
  			break;
  		}

  		/* execute on this thread, no need to process later */

  		if (msg->type == W1_LIST_MASTERS) {
  			err = w1_process_command_root(cn, nsp->portid);

  			goto out_cont;
  		}
  
  		/* All following message types require additional data,
  		 * check here before references are taken.
  		 */

  		if (!msg->len) {

  			err = -EPROTO;
  			goto out_cont;
  		}

  		/* both search calls take references */
  		if (msg->type == W1_MASTER_CMD) {
  			dev = w1_search_master_id(msg->id.mst.id);
  		} else if (msg->type == W1_SLAVE_CMD) {
  			sl = w1_search_slave((struct w1_reg_num *)msg->id.id);

  			if (sl)
  				dev = sl->master;

  		} else {

  			pr_notice("%s: cn: %x.%x, wrong type: %u, len: %u.
  ",

  				__func__, cn->id.idx, cn->id.val,
  				msg->type, msg->len);

  			err = -EPROTO;

  			goto out_cont;

  		}
  
  		if (!dev) {
  			err = -ENODEV;
  			goto out_cont;
  		}

  		err = 0;

  		atomic_inc(&block->refcnt);
  		node->async.cb = w1_process_cb;
  		node->block = block;

  		node->msg = (struct w1_netlink_msg *)((u8 *)&block->request_cn +
  			(size_t)((u8 *)msg - (u8 *)cn));

  		node->sl = sl;
  		node->dev = dev;

  		mutex_lock(&dev->list_mutex);
  		list_add_tail(&node->async.async_entry, &dev->async_list);
  		wake_up_process(dev->thread);
  		mutex_unlock(&dev->list_mutex);
  		++node;

  out_cont:

  		/* Can't queue because that modifies block and another
  		 * thread could be processing the messages by now and
  		 * there isn't a lock, send directly.
  		 */

  		if (err)

  			w1_netlink_send_error(cn, msg, nsp->portid, err);
  		msg_len -= sizeof(struct w1_netlink_msg) + msg->len;
  		msg = (struct w1_netlink_msg *)(((u8 *)msg) +
  			sizeof(struct w1_netlink_msg) + msg->len);

  
  		/*
  		 * Let's allow requests for nonexisting devices.
  		 */
  		if (err == -ENODEV)
  			err = 0;
  	}

  	if (block)
  		w1_unref_block(block);

  }

  int w1_init_netlink(void)

  {

  	struct cb_id w1_id = {.idx = CN_W1_IDX, .val = CN_W1_VAL};
  
  	return cn_add_callback(&w1_id, "w1", &w1_cn_callback);
  }
  
  void w1_fini_netlink(void)
  {
  	struct cb_id w1_id = {.idx = CN_W1_IDX, .val = CN_W1_VAL};
  
  	cn_del_callback(&w1_id);

  }

  #else

  void w1_netlink_send(struct w1_master *dev, struct w1_netlink_msg *cn)

  {
  }

  int w1_init_netlink(void)

  {
  	return 0;
  }

  void w1_fini_netlink(void)

  {
  }

  #endif