#ifndef __NET_GENERIC_NETLINK_H
  #define __NET_GENERIC_NETLINK_H
  
  #include <linux/genetlink.h>
  #include <net/netlink.h>

  #include <net/net_namespace.h>

  
  /**

   * struct genl_multicast_group - generic netlink multicast group
   * @name: name of the multicast group, names are per-family
   * @id: multicast group ID, assigned by the core, to use with
   *      genlmsg_multicast().
   * @list: list entry for linking
   * @family: pointer to family, need not be set before registering
   */

  struct genl_multicast_group {

  	struct genl_family	*family;	/* private */
  	struct list_head	list;		/* private */
  	char			name[GENL_NAMSIZ];
  	u32			id;
  };

  struct genl_ops;
  struct genl_info;

  /**

   * struct genl_family - generic netlink family
   * @id: protocol family idenfitier
   * @hdrsize: length of user specific header in bytes
   * @name: name of family
   * @version: protocol version
   * @maxattr: maximum number of attributes supported

   * @netnsok: set to true if the family can handle network
   *	namespaces and should be presented in all of them

   * @pre_doit: called before an operation's doit callback, it may
   *	do additional, common, filtering and return an error
   * @post_doit: called after an operation's doit callback, it may
   *	undo operations done by pre_doit, for example release locks

   * @attrbuf: buffer to store parsed attributes
   * @ops_list: list of all assigned operations
   * @family_list: family list

   * @mcast_groups: multicast groups list

   */

  struct genl_family {

  	unsigned int		id;
  	unsigned int		hdrsize;
  	char			name[GENL_NAMSIZ];
  	unsigned int		version;
  	unsigned int		maxattr;

  	bool			netnsok;

  	int			(*pre_doit)(struct genl_ops *ops,
  					    struct sk_buff *skb,
  					    struct genl_info *info);
  	void			(*post_doit)(struct genl_ops *ops,
  					     struct sk_buff *skb,
  					     struct genl_info *info);

  	struct nlattr **	attrbuf;	/* private */
  	struct list_head	ops_list;	/* private */
  	struct list_head	family_list;	/* private */

  	struct list_head	mcast_groups;	/* private */

  };

  /**
   * struct genl_info - receiving information
   * @snd_seq: sending sequence number
   * @snd_pid: netlink pid of sender
   * @nlhdr: netlink message header
   * @genlhdr: generic netlink message header
   * @userhdr: user specific header
   * @attrs: netlink attributes

   * @_net: network namespace
   * @user_ptr: user pointers

   */

  struct genl_info {

  	u32			snd_seq;
  	u32			snd_pid;
  	struct nlmsghdr *	nlhdr;
  	struct genlmsghdr *	genlhdr;
  	void *			userhdr;
  	struct nlattr **	attrs;

  #ifdef CONFIG_NET_NS
  	struct net *		_net;
  #endif

  	void *			user_ptr[2];

  };

  static inline struct net *genl_info_net(struct genl_info *info)
  {

  	return read_pnet(&info->_net);

  }
  
  static inline void genl_info_net_set(struct genl_info *info, struct net *net)
  {

  	write_pnet(&info->_net, net);

  }

  /**
   * struct genl_ops - generic netlink operations
   * @cmd: command identifier

   * @internal_flags: flags used by the family

   * @flags: flags
   * @policy: attribute validation policy
   * @doit: standard command callback
   * @dumpit: callback for dumpers

   * @done: completion callback for dumps

   * @ops_list: operations list
   */

  struct genl_ops {

  	u8			cmd;

  	u8			internal_flags;

  	unsigned int		flags;

  	const struct nla_policy	*policy;

  	int		       (*doit)(struct sk_buff *skb,
  				       struct genl_info *info);
  	int		       (*dumpit)(struct sk_buff *skb,
  					 struct netlink_callback *cb);

  	int		       (*done)(struct netlink_callback *cb);

  	struct list_head	ops_list;
  };
  
  extern int genl_register_family(struct genl_family *family);

  extern int genl_register_family_with_ops(struct genl_family *family,
  	struct genl_ops *ops, size_t n_ops);

  extern int genl_unregister_family(struct genl_family *family);
  extern int genl_register_ops(struct genl_family *, struct genl_ops *ops);
  extern int genl_unregister_ops(struct genl_family *, struct genl_ops *ops);

  extern int genl_register_mc_group(struct genl_family *family,
  				  struct genl_multicast_group *grp);
  extern void genl_unregister_mc_group(struct genl_family *family,
  				     struct genl_multicast_group *grp);

  extern void genl_notify(struct sk_buff *skb, struct net *net, u32 pid,
  			u32 group, struct nlmsghdr *nlh, gfp_t flags);

  /**
   * genlmsg_put - Add generic netlink header to netlink message
   * @skb: socket buffer holding the message
   * @pid: netlink pid the message is addressed to
   * @seq: sequence number (usually the one of the sender)

   * @family: generic netlink family

   * @flags netlink message flags
   * @cmd: generic netlink command

   *
   * Returns pointer to user specific header
   */
  static inline void *genlmsg_put(struct sk_buff *skb, u32 pid, u32 seq,

  				struct genl_family *family, int flags, u8 cmd)

  {
  	struct nlmsghdr *nlh;
  	struct genlmsghdr *hdr;

  	nlh = nlmsg_put(skb, pid, seq, family->id, GENL_HDRLEN +
  			family->hdrsize, flags);

  	if (nlh == NULL)
  		return NULL;
  
  	hdr = nlmsg_data(nlh);
  	hdr->cmd = cmd;

  	hdr->version = family->version;

  	hdr->reserved = 0;
  
  	return (char *) hdr + GENL_HDRLEN;
  }
  
  /**

   * genlmsg_nlhdr - Obtain netlink header from user specified header
   * @user_hdr: user header as returned from genlmsg_put()
   * @family: generic netlink family
   *
   * Returns pointer to netlink header.
   */
  static inline struct nlmsghdr *genlmsg_nlhdr(void *user_hdr,
  					     struct genl_family *family)
  {
  	return (struct nlmsghdr *)((char *)user_hdr -
  				   family->hdrsize -
  				   GENL_HDRLEN -
  				   NLMSG_HDRLEN);
  }
  
  /**
   * genl_dump_check_consistent - check if sequence is consistent and advertise if not
   * @cb: netlink callback structure that stores the sequence number
   * @user_hdr: user header as returned from genlmsg_put()
   * @family: generic netlink family
   *
   * Cf. nl_dump_check_consistent(), this just provides a wrapper to make it
   * simpler to use with generic netlink.
   */
  static inline void genl_dump_check_consistent(struct netlink_callback *cb,
  					      void *user_hdr,
  					      struct genl_family *family)
  {
  	nl_dump_check_consistent(cb, genlmsg_nlhdr(user_hdr, family));
  }
  
  /**

   * genlmsg_put_reply - Add generic netlink header to a reply message
   * @skb: socket buffer holding the message
   * @info: receiver info
   * @family: generic netlink family
   * @flags: netlink message flags
   * @cmd: generic netlink command
   *
   * Returns pointer to user specific header
   */
  static inline void *genlmsg_put_reply(struct sk_buff *skb,
  				      struct genl_info *info,
  				      struct genl_family *family,
  				      int flags, u8 cmd)
  {
  	return genlmsg_put(skb, info->snd_pid, info->snd_seq, family,
  			   flags, cmd);
  }
  
  /**

   * genlmsg_end - Finalize a generic netlink message
   * @skb: socket buffer the message is stored in
   * @hdr: user specific header
   */
  static inline int genlmsg_end(struct sk_buff *skb, void *hdr)
  {
  	return nlmsg_end(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);
  }
  
  /**
   * genlmsg_cancel - Cancel construction of a generic netlink message
   * @skb: socket buffer the message is stored in
   * @hdr: generic netlink message header
   */

  static inline void genlmsg_cancel(struct sk_buff *skb, void *hdr)

  {

  	if (hdr)
  		nlmsg_cancel(skb, hdr - GENL_HDRLEN - NLMSG_HDRLEN);

  }
  
  /**

   * genlmsg_multicast_netns - multicast a netlink message to a specific netns
   * @net: the net namespace
   * @skb: netlink message as socket buffer
   * @pid: own netlink pid to avoid sending to yourself
   * @group: multicast group id
   * @flags: allocation flags
   */
  static inline int genlmsg_multicast_netns(struct net *net, struct sk_buff *skb,
  					  u32 pid, unsigned int group, gfp_t flags)
  {
  	return nlmsg_multicast(net->genl_sock, skb, pid, group, flags);
  }
  
  /**
   * genlmsg_multicast - multicast a netlink message to the default netns

   * @skb: netlink message as socket buffer
   * @pid: own netlink pid to avoid sending to yourself
   * @group: multicast group id

   * @flags: allocation flags

   */
  static inline int genlmsg_multicast(struct sk_buff *skb, u32 pid,

  				    unsigned int group, gfp_t flags)

  {

  	return genlmsg_multicast_netns(&init_net, skb, pid, group, flags);

  }
  
  /**

   * genlmsg_multicast_allns - multicast a netlink message to all net namespaces
   * @skb: netlink message as socket buffer
   * @pid: own netlink pid to avoid sending to yourself
   * @group: multicast group id
   * @flags: allocation flags
   *
   * This function must hold the RTNL or rcu_read_lock().
   */
  int genlmsg_multicast_allns(struct sk_buff *skb, u32 pid,
  			    unsigned int group, gfp_t flags);
  
  /**

   * genlmsg_unicast - unicast a netlink message
   * @skb: netlink message as socket buffer
   * @pid: netlink pid of the destination socket
   */

  static inline int genlmsg_unicast(struct net *net, struct sk_buff *skb, u32 pid)

  {

  	return nlmsg_unicast(net->genl_sock, skb, pid);

  }

  /**

   * genlmsg_reply - reply to a request
   * @skb: netlink message to be sent back
   * @info: receiver information
   */
  static inline int genlmsg_reply(struct sk_buff *skb, struct genl_info *info)
  {

  	return genlmsg_unicast(genl_info_net(info), skb, info->snd_pid);

  }
  
  /**

   * gennlmsg_data - head of message payload

   * @gnlh: genetlink message header

   */
  static inline void *genlmsg_data(const struct genlmsghdr *gnlh)
  {
  	return ((unsigned char *) gnlh + GENL_HDRLEN);
  }
  
  /**
   * genlmsg_len - length of message payload
   * @gnlh: genetlink message header
   */
  static inline int genlmsg_len(const struct genlmsghdr *gnlh)
  {
  	struct nlmsghdr *nlh = (struct nlmsghdr *)((unsigned char *)gnlh -
  							NLMSG_HDRLEN);
  	return (nlh->nlmsg_len - GENL_HDRLEN - NLMSG_HDRLEN);
  }

  /**
   * genlmsg_msg_size - length of genetlink message not including padding
   * @payload: length of message payload
   */
  static inline int genlmsg_msg_size(int payload)
  {
  	return GENL_HDRLEN + payload;
  }
  
  /**
   * genlmsg_total_size - length of genetlink message including padding
   * @payload: length of message payload
   */
  static inline int genlmsg_total_size(int payload)
  {
  	return NLMSG_ALIGN(genlmsg_msg_size(payload));
  }

  /**
   * genlmsg_new - Allocate a new generic netlink message
   * @payload: size of the message payload
   * @flags: the type of memory to allocate.
   */
  static inline struct sk_buff *genlmsg_new(size_t payload, gfp_t flags)
  {
  	return nlmsg_new(genlmsg_total_size(payload), flags);
  }

  #endif	/* __NET_GENERIC_NETLINK_H */