include/net/genetlink.h - linux - Git at Google

 /* SPDX-License-Identifier: GPL-2.0 */
 #ifndef __NET_GENERIC_NETLINK_H
 #define __NET_GENERIC_NETLINK_H

 #include <linux/genetlink.h>
 #include <net/netlink.h>
 #include <net/net_namespace.h>

 #define GENLMSG_DEFAULT_SIZE (NLMSG_DEFAULT_SIZE - GENL_HDRLEN)

 /**
  * struct genl_multicast_group - generic netlink multicast group
  * @name: name of the multicast group, names are per-family
  * @flags: GENL_* flags (%GENL_ADMIN_PERM or %GENL_UNS_ADMIN_PERM)
  */
 struct genl_multicast_group {
 	char			name[GENL_NAMSIZ];
 	u8			flags;
 };

 struct genl_split_ops;
 struct genl_info;

 /**
  * struct genl_family - generic netlink family
  * @hdrsize: length of user specific header in bytes
  * @name: name of family
  * @version: protocol version
  * @maxattr: maximum number of attributes supported
  * @policy: netlink policy
  * @netnsok: set to true if the family can handle network
  *	namespaces and should be presented in all of them
  * @parallel_ops: operations can be called in parallel and aren't
  *	synchronized by the core genetlink code
  * @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
  * @module: pointer to the owning module (set to THIS_MODULE)
  * @mcgrps: multicast groups used by this family
  * @n_mcgrps: number of multicast groups
  * @resv_start_op: first operation for which reserved fields of the header
  *	can be validated and policies are required (see below);
  *	new families should leave this field at zero
  * @ops: the operations supported by this family
  * @n_ops: number of operations supported by this family
  * @small_ops: the small-struct operations supported by this family
  * @n_small_ops: number of small-struct operations supported by this family
  * @split_ops: the split do/dump form of operation definition
  * @n_split_ops: number of entries in @split_ops, not that with split do/dump
  *	ops the number of entries is not the same as number of commands
  *
  * Attribute policies (the combination of @policy and @maxattr fields)
  * can be attached at the family level or at the operation level.
  * If both are present the per-operation policy takes precedence.
  * For operations before @resv_start_op lack of policy means that the core
  * will perform no attribute parsing or validation. For newer operations
  * if policy is not provided core will reject all TLV attributes.
  */
 struct genl_family {
 	unsigned int		hdrsize;
 	char			name[GENL_NAMSIZ];
 	unsigned int		version;
 	unsigned int		maxattr;
 	u8			netnsok:1;
 	u8			parallel_ops:1;
 	u8			n_ops;
 	u8			n_small_ops;
 	u8			n_split_ops;
 	u8			n_mcgrps;
 	u8			resv_start_op;
 	const struct nla_policy *policy;
 	int			(*pre_doit)(const struct genl_split_ops *ops,
 					    struct sk_buff *skb,
 					    struct genl_info *info);
 	void			(*post_doit)(const struct genl_split_ops *ops,
 					     struct sk_buff *skb,
 					     struct genl_info *info);
 	const struct genl_ops *	ops;
 	const struct genl_small_ops *small_ops;
 	const struct genl_split_ops *split_ops;
 	const struct genl_multicast_group *mcgrps;
 	struct module		*module;

 /* private: internal use only */
 	/* protocol family identifier */
 	int			id;
 	/* starting number of multicast group IDs in this family */
 	unsigned int		mcgrp_offset;
 };

 /**
  * struct genl_info - receiving information
  * @snd_seq: sending sequence number
  * @snd_portid: netlink portid of sender
  * @family: generic netlink family
  * @nlhdr: netlink message header
  * @genlhdr: generic netlink message header
  * @attrs: netlink attributes
  * @_net: network namespace
  * @user_ptr: user pointers
  * @extack: extended ACK report struct
  */
 struct genl_info {
 	u32			snd_seq;
 	u32			snd_portid;
 	const struct genl_family *family;
 	const struct nlmsghdr *	nlhdr;
 	struct genlmsghdr *	genlhdr;
 	struct nlattr **	attrs;
 	possible_net_t		_net;
 	void *			user_ptr[2];
 	struct netlink_ext_ack *extack;
 };

 static inline struct net *genl_info_net(const 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);
 }

 static inline void *genl_info_userhdr(const struct genl_info *info)
 {
 	return (u8 *)info->genlhdr + GENL_HDRLEN;
 }

 #define GENL_SET_ERR_MSG(info, msg) NL_SET_ERR_MSG((info)->extack, msg)

 #define GENL_SET_ERR_MSG_FMT(info, msg, args...) \
 	NL_SET_ERR_MSG_FMT((info)->extack, msg, ##args)

 /* Report that a root attribute is missing */
 #define GENL_REQ_ATTR_CHECK(info, attr) ({				\
 	struct genl_info *__info = (info);				\
 									\
 	NL_REQ_ATTR_CHECK(__info->extack, NULL, __info->attrs, (attr)); \
 })

 enum genl_validate_flags {
 	GENL_DONT_VALIDATE_STRICT		= BIT(0),
 	GENL_DONT_VALIDATE_DUMP			= BIT(1),
 	GENL_DONT_VALIDATE_DUMP_STRICT		= BIT(2),
 };

 /**
  * struct genl_small_ops - generic netlink operations (small version)
  * @cmd: command identifier
  * @internal_flags: flags used by the family
  * @flags: GENL_* flags (%GENL_ADMIN_PERM or %GENL_UNS_ADMIN_PERM)
  * @validate: validation flags from enum genl_validate_flags
  * @doit: standard command callback
  * @dumpit: callback for dumpers
  *
  * This is a cut-down version of struct genl_ops for users who don't need
  * most of the ancillary infra and want to save space.
  */
 struct genl_small_ops {
 	int	(*doit)(struct sk_buff *skb, struct genl_info *info);
 	int	(*dumpit)(struct sk_buff *skb, struct netlink_callback *cb);
 	u8	cmd;
 	u8	internal_flags;
 	u8	flags;
 	u8	validate;
 };

 /**
  * struct genl_ops - generic netlink operations
  * @cmd: command identifier
  * @internal_flags: flags used by the family
  * @flags: GENL_* flags (%GENL_ADMIN_PERM or %GENL_UNS_ADMIN_PERM)
  * @maxattr: maximum number of attributes supported
  * @policy: netlink policy (takes precedence over family policy)
  * @validate: validation flags from enum genl_validate_flags
  * @doit: standard command callback
  * @start: start callback for dumps
  * @dumpit: callback for dumpers
  * @done: completion callback for dumps
  */
 struct genl_ops {
 	int		       (*doit)(struct sk_buff *skb,
 				       struct genl_info *info);
 	int		       (*start)(struct netlink_callback *cb);
 	int		       (*dumpit)(struct sk_buff *skb,
 					 struct netlink_callback *cb);
 	int		       (*done)(struct netlink_callback *cb);
 	const struct nla_policy *policy;
 	unsigned int		maxattr;
 	u8			cmd;
 	u8			internal_flags;
 	u8			flags;
 	u8			validate;
 };

 /**
  * struct genl_split_ops - generic netlink operations (do/dump split version)
  * @cmd: command identifier
  * @internal_flags: flags used by the family
  * @flags: GENL_* flags (%GENL_ADMIN_PERM or %GENL_UNS_ADMIN_PERM)
  * @validate: validation flags from enum genl_validate_flags
  * @policy: netlink policy (takes precedence over family policy)
  * @maxattr: maximum number of attributes supported
  *
  * Do callbacks:
  * @pre_doit: called before an operation's @doit callback, it may
  *	do additional, common, filtering and return an error
  * @doit: standard command callback
  * @post_doit: called after an operation's @doit callback, it may
  *	undo operations done by pre_doit, for example release locks
  *
  * Dump callbacks:
  * @start: start callback for dumps
  * @dumpit: callback for dumpers
  * @done: completion callback for dumps
  *
  * Do callbacks can be used if %GENL_CMD_CAP_DO is set in @flags.
  * Dump callbacks can be used if %GENL_CMD_CAP_DUMP is set in @flags.
  * Exactly one of those flags must be set.
  */
 struct genl_split_ops {
 	union {
 		struct {
 			int (*pre_doit)(const struct genl_split_ops *ops,
 					struct sk_buff *skb,
 					struct genl_info *info);
 			int (*doit)(struct sk_buff *skb,
 				    struct genl_info *info);
 			void (*post_doit)(const struct genl_split_ops *ops,
 					  struct sk_buff *skb,
 					  struct genl_info *info);
 		};
 		struct {
 			int (*start)(struct netlink_callback *cb);
 			int (*dumpit)(struct sk_buff *skb,
 				      struct netlink_callback *cb);
 			int (*done)(struct netlink_callback *cb);
 		};
 	};
 	const struct nla_policy *policy;
 	unsigned int		maxattr;
 	u8			cmd;
 	u8			internal_flags;
 	u8			flags;
 	u8			validate;
 };

 /**
  * struct genl_dumpit_info - info that is available during dumpit op call
  * @op: generic netlink ops - for internal genl code usage
  * @attrs: netlink attributes
  * @info: struct genl_info describing the request
  */
 struct genl_dumpit_info {
 	struct genl_split_ops op;
 	struct genl_info info;
 };

 static inline const struct genl_dumpit_info *
 genl_dumpit_info(struct netlink_callback *cb)
 {
 	return cb->data;
 }

 static inline const struct genl_info *
 genl_info_dump(struct netlink_callback *cb)
 {
 	return &genl_dumpit_info(cb)->info;
 }

 /**
  * genl_info_init_ntf() - initialize genl_info for notifications
  * @info:   genl_info struct to set up
  * @family: pointer to the genetlink family
  * @cmd:    command to be used in the notification
  *
  * Initialize a locally declared struct genl_info to pass to various APIs.
  * Intended to be used when creating notifications.
  */
 static inline void
 genl_info_init_ntf(struct genl_info *info, const struct genl_family *family,
 		   u8 cmd)
 {
 	struct genlmsghdr *hdr = (void *) &info->user_ptr[0];

 	memset(info, 0, sizeof(*info));
 	info->family = family;
 	info->genlhdr = hdr;
 	hdr->cmd = cmd;
 }

 static inline bool genl_info_is_ntf(const struct genl_info *info)
 {
 	return !info->nlhdr;
 }

 int genl_register_family(struct genl_family *family);
 int genl_unregister_family(const struct genl_family *family);
 void genl_notify(const struct genl_family *family, struct sk_buff *skb,
 		 struct genl_info *info, u32 group, gfp_t flags);

 void *genlmsg_put(struct sk_buff *skb, u32 portid, u32 seq,
 		  const struct genl_family *family, int flags, u8 cmd);

 static inline void *
 __genlmsg_iput(struct sk_buff *skb, const struct genl_info *info, int flags)
 {
 	return genlmsg_put(skb, info->snd_portid, info->snd_seq, info->family,
 			   flags, info->genlhdr->cmd);
 }

 /**
  * genlmsg_iput - start genetlink message based on genl_info
  * @skb: skb in which message header will be placed
  * @info: genl_info as provided to do/dump handlers
  *
  * Convenience wrapper which starts a genetlink message based on
  * information in user request. @info should be either the struct passed
  * by genetlink core to do/dump handlers (when constructing replies to
  * such requests) or a struct initialized by genl_info_init_ntf()
  * when constructing notifications.
  *
  * Returns pointer to new genetlink header.
  */
 static inline void *
 genlmsg_iput(struct sk_buff *skb, const struct genl_info *info)
 {
 	return __genlmsg_iput(skb, info, 0);
 }

 /**
  * genlmsg_nlhdr - Obtain netlink header from user specified header
  * @user_hdr: user header as returned from genlmsg_put()
  *
  * Returns pointer to netlink header.
  */
 static inline struct nlmsghdr *genlmsg_nlhdr(void *user_hdr)
 {
 	return (struct nlmsghdr *)((char *)user_hdr -
 				   GENL_HDRLEN -
 				   NLMSG_HDRLEN);
 }

 /**
  * genlmsg_parse_deprecated - parse attributes of a genetlink message
  * @nlh: netlink message header
  * @family: genetlink message family
  * @tb: destination array with maxtype+1 elements
  * @maxtype: maximum attribute type to be expected
  * @policy: validation policy
  * @extack: extended ACK report struct
  */
 static inline int genlmsg_parse_deprecated(const struct nlmsghdr *nlh,
 					   const struct genl_family *family,
 					   struct nlattr *tb[], int maxtype,
 					   const struct nla_policy *policy,
 					   struct netlink_ext_ack *extack)
 {
 	return __nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype,
 			     policy, NL_VALIDATE_LIBERAL, extack);
 }

 /**
  * genlmsg_parse - parse attributes of a genetlink message
  * @nlh: netlink message header
  * @family: genetlink message family
  * @tb: destination array with maxtype+1 elements
  * @maxtype: maximum attribute type to be expected
  * @policy: validation policy
  * @extack: extended ACK report struct
  */
 static inline int genlmsg_parse(const struct nlmsghdr *nlh,
 				const struct genl_family *family,
 				struct nlattr *tb[], int maxtype,
 				const struct nla_policy *policy,
 				struct netlink_ext_ack *extack)
 {
 	return __nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype,
 			     policy, NL_VALIDATE_STRICT, extack);
 }

 /**
  * 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()
  *
  * 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)
 {
 	nl_dump_check_consistent(cb, genlmsg_nlhdr(user_hdr));
 }

 /**
  * 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,
 				      const struct genl_family *family,
 				      int flags, u8 cmd)
 {
 	return genlmsg_put(skb, info->snd_portid, 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 void genlmsg_end(struct sk_buff *skb, void *hdr)
 {
 	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
  * @family: the generic netlink family
  * @net: the net namespace
  * @skb: netlink message as socket buffer
  * @portid: own netlink portid to avoid sending to yourself
  * @group: offset of multicast group in groups array
  * @flags: allocation flags
  */
 static inline int genlmsg_multicast_netns(const struct genl_family *family,
 					  struct net *net, struct sk_buff *skb,
 					  u32 portid, unsigned int group, gfp_t flags)
 {
 	if (WARN_ON_ONCE(group >= family->n_mcgrps))
 		return -EINVAL;
 	group = family->mcgrp_offset + group;
 	return nlmsg_multicast(net->genl_sock, skb, portid, group, flags);
 }

 /**
  * genlmsg_multicast - multicast a netlink message to the default netns
  * @family: the generic netlink family
  * @skb: netlink message as socket buffer
  * @portid: own netlink portid to avoid sending to yourself
  * @group: offset of multicast group in groups array
  * @flags: allocation flags
  */
 static inline int genlmsg_multicast(const struct genl_family *family,
 				    struct sk_buff *skb, u32 portid,
 				    unsigned int group, gfp_t flags)
 {
 	return genlmsg_multicast_netns(family, &init_net, skb,
 				       portid, group, flags);
 }

 /**
  * genlmsg_multicast_allns - multicast a netlink message to all net namespaces
  * @family: the generic netlink family
  * @skb: netlink message as socket buffer
  * @portid: own netlink portid to avoid sending to yourself
  * @group: offset of multicast group in groups array
  * @flags: allocation flags
  *
  * This function must hold the RTNL or rcu_read_lock().
  */
 int genlmsg_multicast_allns(const struct genl_family *family,
 			    struct sk_buff *skb, u32 portid,
 			    unsigned int group, gfp_t flags);

 /**
  * genlmsg_unicast - unicast a netlink message
  * @net: network namespace to look up @portid in
  * @skb: netlink message as socket buffer
  * @portid: netlink portid of the destination socket
  */
 static inline int genlmsg_unicast(struct net *net, struct sk_buff *skb, u32 portid)
 {
 	return nlmsg_unicast(net->genl_sock, skb, portid);
 }

 /**
  * 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_portid);
 }

 /**
  * genlmsg_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);
 }

 /**
  * genl_set_err - report error to genetlink broadcast listeners
  * @family: the generic netlink family
  * @net: the network namespace to report the error to
  * @portid: the PORTID of a process that we want to skip (if any)
  * @group: the broadcast group that will notice the error
  * 	(this is the offset of the multicast group in the groups array)
  * @code: error code, must be negative (as usual in kernelspace)
  *
  * This function returns the number of broadcast listeners that have set the
  * NETLINK_RECV_NO_ENOBUFS socket option.
  */
 static inline int genl_set_err(const struct genl_family *family,
 			       struct net *net, u32 portid,
 			       u32 group, int code)
 {
 	if (WARN_ON_ONCE(group >= family->n_mcgrps))
 		return -EINVAL;
 	group = family->mcgrp_offset + group;
 	return netlink_set_err(net->genl_sock, portid, group, code);
 }

 static inline int genl_has_listeners(const struct genl_family *family,
 				     struct net *net, unsigned int group)
 {
 	if (WARN_ON_ONCE(group >= family->n_mcgrps))
 		return -EINVAL;
 	group = family->mcgrp_offset + group;
 	return netlink_has_listeners(net->genl_sock, group);
 }
 #endif	/* __NET_GENERIC_NETLINK_H */
	/* SPDX-License-Identifier: GPL-2.0 */
	#ifndef __NET_GENERIC_NETLINK_H
	#define __NET_GENERIC_NETLINK_H

	#include <linux/genetlink.h>
	#include <net/netlink.h>
	#include <net/net_namespace.h>

	#define GENLMSG_DEFAULT_SIZE (NLMSG_DEFAULT_SIZE - GENL_HDRLEN)

	/**
	* struct genl_multicast_group - generic netlink multicast group
	* @name: name of the multicast group, names are per-family
	* @flags: GENL_* flags (%GENL_ADMIN_PERM or %GENL_UNS_ADMIN_PERM)
	*/
	struct genl_multicast_group {
	char name[GENL_NAMSIZ];
	u8 flags;
	};

	struct genl_split_ops;
	struct genl_info;

	/**
	* struct genl_family - generic netlink family
	* @hdrsize: length of user specific header in bytes
	* @name: name of family
	* @version: protocol version
	* @maxattr: maximum number of attributes supported
	* @policy: netlink policy
	* @netnsok: set to true if the family can handle network
	* namespaces and should be presented in all of them
	* @parallel_ops: operations can be called in parallel and aren't
	* synchronized by the core genetlink code
	* @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
	* @module: pointer to the owning module (set to THIS_MODULE)
	* @mcgrps: multicast groups used by this family
	* @n_mcgrps: number of multicast groups
	* @resv_start_op: first operation for which reserved fields of the header
	* can be validated and policies are required (see below);
	* new families should leave this field at zero
	* @ops: the operations supported by this family
	* @n_ops: number of operations supported by this family
	* @small_ops: the small-struct operations supported by this family
	* @n_small_ops: number of small-struct operations supported by this family
	* @split_ops: the split do/dump form of operation definition
	* @n_split_ops: number of entries in @split_ops, not that with split do/dump
	* ops the number of entries is not the same as number of commands
	*
	* Attribute policies (the combination of @policy and @maxattr fields)
	* can be attached at the family level or at the operation level.
	* If both are present the per-operation policy takes precedence.
	* For operations before @resv_start_op lack of policy means that the core
	* will perform no attribute parsing or validation. For newer operations
	* if policy is not provided core will reject all TLV attributes.
	*/
	struct genl_family {
	unsigned int hdrsize;
	char name[GENL_NAMSIZ];
	unsigned int version;
	unsigned int maxattr;
	u8 netnsok:1;
	u8 parallel_ops:1;
	u8 n_ops;
	u8 n_small_ops;
	u8 n_split_ops;
	u8 n_mcgrps;
	u8 resv_start_op;
	const struct nla_policy *policy;
	int (pre_doit)(const struct genl_split_ops ops,
	struct sk_buff *skb,
	struct genl_info *info);
	void (post_doit)(const struct genl_split_ops ops,
	struct sk_buff *skb,
	struct genl_info *info);
	const struct genl_ops * ops;
	const struct genl_small_ops *small_ops;
	const struct genl_split_ops *split_ops;
	const struct genl_multicast_group *mcgrps;
	struct module *module;

	/* private: internal use only */
	/* protocol family identifier */
	int id;
	/* starting number of multicast group IDs in this family */
	unsigned int mcgrp_offset;
	};

	/**
	* struct genl_info - receiving information
	* @snd_seq: sending sequence number
	* @snd_portid: netlink portid of sender
	* @family: generic netlink family
	* @nlhdr: netlink message header
	* @genlhdr: generic netlink message header
	* @attrs: netlink attributes
	* @_net: network namespace
	* @user_ptr: user pointers
	* @extack: extended ACK report struct
	*/
	struct genl_info {
	u32 snd_seq;
	u32 snd_portid;
	const struct genl_family *family;
	const struct nlmsghdr * nlhdr;
	struct genlmsghdr * genlhdr;
	struct nlattr ** attrs;
	possible_net_t _net;
	void * user_ptr[2];
	struct netlink_ext_ack *extack;
	};

	static inline struct net genl_info_net(const 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);
	}

	static inline void genl_info_userhdr(const struct genl_info info)
	{
	return (u8 *)info->genlhdr + GENL_HDRLEN;
	}

	#define GENL_SET_ERR_MSG(info, msg) NL_SET_ERR_MSG((info)->extack, msg)

	#define GENL_SET_ERR_MSG_FMT(info, msg, args...) \
	NL_SET_ERR_MSG_FMT((info)->extack, msg, ##args)

	/* Report that a root attribute is missing */
	#define GENL_REQ_ATTR_CHECK(info, attr) ({ \
	struct genl_info *__info = (info); \
	\
	NL_REQ_ATTR_CHECK(__info->extack, NULL, __info->attrs, (attr)); \
	})

	enum genl_validate_flags {
	GENL_DONT_VALIDATE_STRICT = BIT(0),
	GENL_DONT_VALIDATE_DUMP = BIT(1),
	GENL_DONT_VALIDATE_DUMP_STRICT = BIT(2),
	};

	/**
	* struct genl_small_ops - generic netlink operations (small version)
	* @cmd: command identifier
	* @internal_flags: flags used by the family
	* @flags: GENL_* flags (%GENL_ADMIN_PERM or %GENL_UNS_ADMIN_PERM)
	* @validate: validation flags from enum genl_validate_flags
	* @doit: standard command callback
	* @dumpit: callback for dumpers
	*
	* This is a cut-down version of struct genl_ops for users who don't need
	* most of the ancillary infra and want to save space.
	*/
	struct genl_small_ops {
	int (doit)(struct sk_buff skb, struct genl_info *info);
	int (dumpit)(struct sk_buff skb, struct netlink_callback *cb);
	u8 cmd;
	u8 internal_flags;
	u8 flags;
	u8 validate;
	};

	/**
	* struct genl_ops - generic netlink operations
	* @cmd: command identifier
	* @internal_flags: flags used by the family
	* @flags: GENL_* flags (%GENL_ADMIN_PERM or %GENL_UNS_ADMIN_PERM)
	* @maxattr: maximum number of attributes supported
	* @policy: netlink policy (takes precedence over family policy)
	* @validate: validation flags from enum genl_validate_flags
	* @doit: standard command callback
	* @start: start callback for dumps
	* @dumpit: callback for dumpers
	* @done: completion callback for dumps
	*/
	struct genl_ops {
	int (doit)(struct sk_buff skb,
	struct genl_info *info);
	int (start)(struct netlink_callback cb);
	int (dumpit)(struct sk_buff skb,
	struct netlink_callback *cb);
	int (done)(struct netlink_callback cb);
	const struct nla_policy *policy;
	unsigned int maxattr;
	u8 cmd;
	u8 internal_flags;
	u8 flags;
	u8 validate;
	};

	/**
	* struct genl_split_ops - generic netlink operations (do/dump split version)
	* @cmd: command identifier
	* @internal_flags: flags used by the family
	* @flags: GENL_* flags (%GENL_ADMIN_PERM or %GENL_UNS_ADMIN_PERM)
	* @validate: validation flags from enum genl_validate_flags
	* @policy: netlink policy (takes precedence over family policy)
	* @maxattr: maximum number of attributes supported
	*
	* Do callbacks:
	* @pre_doit: called before an operation's @doit callback, it may
	* do additional, common, filtering and return an error
	* @doit: standard command callback
	* @post_doit: called after an operation's @doit callback, it may
	* undo operations done by pre_doit, for example release locks
	*
	* Dump callbacks:
	* @start: start callback for dumps
	* @dumpit: callback for dumpers
	* @done: completion callback for dumps
	*
	* Do callbacks can be used if %GENL_CMD_CAP_DO is set in @flags.
	* Dump callbacks can be used if %GENL_CMD_CAP_DUMP is set in @flags.
	* Exactly one of those flags must be set.
	*/
	struct genl_split_ops {
	union {
	struct {
	int (pre_doit)(const struct genl_split_ops ops,
	struct sk_buff *skb,
	struct genl_info *info);
	int (doit)(struct sk_buff skb,
	struct genl_info *info);
	void (post_doit)(const struct genl_split_ops ops,
	struct sk_buff *skb,
	struct genl_info *info);
	};
	struct {
	int (start)(struct netlink_callback cb);
	int (dumpit)(struct sk_buff skb,
	struct netlink_callback *cb);
	int (done)(struct netlink_callback cb);
	};
	};
	const struct nla_policy *policy;
	unsigned int maxattr;
	u8 cmd;
	u8 internal_flags;
	u8 flags;
	u8 validate;
	};

	/**
	* struct genl_dumpit_info - info that is available during dumpit op call
	* @op: generic netlink ops - for internal genl code usage
	* @attrs: netlink attributes
	* @info: struct genl_info describing the request
	*/
	struct genl_dumpit_info {
	struct genl_split_ops op;
	struct genl_info info;
	};

	static inline const struct genl_dumpit_info *
	genl_dumpit_info(struct netlink_callback *cb)
	{
	return cb->data;
	}

	static inline const struct genl_info *
	genl_info_dump(struct netlink_callback *cb)
	{
	return &genl_dumpit_info(cb)->info;
	}

	/**
	* genl_info_init_ntf() - initialize genl_info for notifications
	* @info: genl_info struct to set up
	* @family: pointer to the genetlink family
	* @cmd: command to be used in the notification
	*
	* Initialize a locally declared struct genl_info to pass to various APIs.
	* Intended to be used when creating notifications.
	*/
	static inline void
	genl_info_init_ntf(struct genl_info info, const struct genl_family family,
	u8 cmd)
	{
	struct genlmsghdr hdr = (void ) &info->user_ptr[0];

	memset(info, 0, sizeof(*info));
	info->family = family;
	info->genlhdr = hdr;
	hdr->cmd = cmd;
	}

	static inline bool genl_info_is_ntf(const struct genl_info *info)
	{
	return !info->nlhdr;
	}

	int genl_register_family(struct genl_family *family);
	int genl_unregister_family(const struct genl_family *family);
	void genl_notify(const struct genl_family family, struct sk_buff skb,
	struct genl_info *info, u32 group, gfp_t flags);

	void genlmsg_put(struct sk_buff skb, u32 portid, u32 seq,
	const struct genl_family *family, int flags, u8 cmd);

	static inline void *
	__genlmsg_iput(struct sk_buff skb, const struct genl_info info, int flags)
	{
	return genlmsg_put(skb, info->snd_portid, info->snd_seq, info->family,
	flags, info->genlhdr->cmd);
	}

	/**
	* genlmsg_iput - start genetlink message based on genl_info
	* @skb: skb in which message header will be placed
	* @info: genl_info as provided to do/dump handlers
	*
	* Convenience wrapper which starts a genetlink message based on
	* information in user request. @info should be either the struct passed
	* by genetlink core to do/dump handlers (when constructing replies to
	* such requests) or a struct initialized by genl_info_init_ntf()
	* when constructing notifications.
	*
	* Returns pointer to new genetlink header.
	*/
	static inline void *
	genlmsg_iput(struct sk_buff skb, const struct genl_info info)
	{
	return __genlmsg_iput(skb, info, 0);
	}

	/**
	* genlmsg_nlhdr - Obtain netlink header from user specified header
	* @user_hdr: user header as returned from genlmsg_put()
	*
	* Returns pointer to netlink header.
	*/
	static inline struct nlmsghdr genlmsg_nlhdr(void user_hdr)
	{
	return (struct nlmsghdr )((char )user_hdr -
	GENL_HDRLEN -
	NLMSG_HDRLEN);
	}

	/**
	* genlmsg_parse_deprecated - parse attributes of a genetlink message
	* @nlh: netlink message header
	* @family: genetlink message family
	* @tb: destination array with maxtype+1 elements
	* @maxtype: maximum attribute type to be expected
	* @policy: validation policy
	* @extack: extended ACK report struct
	*/
	static inline int genlmsg_parse_deprecated(const struct nlmsghdr *nlh,
	const struct genl_family *family,
	struct nlattr *tb[], int maxtype,
	const struct nla_policy *policy,
	struct netlink_ext_ack *extack)
	{
	return __nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype,
	policy, NL_VALIDATE_LIBERAL, extack);
	}

	/**
	* genlmsg_parse - parse attributes of a genetlink message
	* @nlh: netlink message header
	* @family: genetlink message family
	* @tb: destination array with maxtype+1 elements
	* @maxtype: maximum attribute type to be expected
	* @policy: validation policy
	* @extack: extended ACK report struct
	*/
	static inline int genlmsg_parse(const struct nlmsghdr *nlh,
	const struct genl_family *family,
	struct nlattr *tb[], int maxtype,
	const struct nla_policy *policy,
	struct netlink_ext_ack *extack)
	{
	return __nlmsg_parse(nlh, family->hdrsize + GENL_HDRLEN, tb, maxtype,
	policy, NL_VALIDATE_STRICT, extack);
	}

	/**
	* 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()
	*
	* 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)
	{
	nl_dump_check_consistent(cb, genlmsg_nlhdr(user_hdr));
	}

	/**
	* 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,
	const struct genl_family *family,
	int flags, u8 cmd)
	{
	return genlmsg_put(skb, info->snd_portid, 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 void genlmsg_end(struct sk_buff skb, void hdr)
	{
	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
	* @family: the generic netlink family
	* @net: the net namespace
	* @skb: netlink message as socket buffer
	* @portid: own netlink portid to avoid sending to yourself
	* @group: offset of multicast group in groups array
	* @flags: allocation flags
	*/
	static inline int genlmsg_multicast_netns(const struct genl_family *family,
	struct net net, struct sk_buff skb,
	u32 portid, unsigned int group, gfp_t flags)
	{
	if (WARN_ON_ONCE(group >= family->n_mcgrps))
	return -EINVAL;
	group = family->mcgrp_offset + group;
	return nlmsg_multicast(net->genl_sock, skb, portid, group, flags);
	}

	/**
	* genlmsg_multicast - multicast a netlink message to the default netns
	* @family: the generic netlink family
	* @skb: netlink message as socket buffer
	* @portid: own netlink portid to avoid sending to yourself
	* @group: offset of multicast group in groups array
	* @flags: allocation flags
	*/
	static inline int genlmsg_multicast(const struct genl_family *family,
	struct sk_buff *skb, u32 portid,
	unsigned int group, gfp_t flags)
	{
	return genlmsg_multicast_netns(family, &init_net, skb,
	portid, group, flags);
	}

	/**
	* genlmsg_multicast_allns - multicast a netlink message to all net namespaces
	* @family: the generic netlink family
	* @skb: netlink message as socket buffer
	* @portid: own netlink portid to avoid sending to yourself
	* @group: offset of multicast group in groups array
	* @flags: allocation flags
	*
	* This function must hold the RTNL or rcu_read_lock().
	*/
	int genlmsg_multicast_allns(const struct genl_family *family,
	struct sk_buff *skb, u32 portid,
	unsigned int group, gfp_t flags);

	/**
	* genlmsg_unicast - unicast a netlink message
	* @net: network namespace to look up @portid in
	* @skb: netlink message as socket buffer
	* @portid: netlink portid of the destination socket
	*/
	static inline int genlmsg_unicast(struct net net, struct sk_buff skb, u32 portid)
	{
	return nlmsg_unicast(net->genl_sock, skb, portid);
	}

	/**
	* 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_portid);
	}

	/**
	* genlmsg_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);
	}

	/**
	* genl_set_err - report error to genetlink broadcast listeners
	* @family: the generic netlink family
	* @net: the network namespace to report the error to
	* @portid: the PORTID of a process that we want to skip (if any)
	* @group: the broadcast group that will notice the error
	* (this is the offset of the multicast group in the groups array)
	* @code: error code, must be negative (as usual in kernelspace)
	*
	* This function returns the number of broadcast listeners that have set the
	* NETLINK_RECV_NO_ENOBUFS socket option.
	*/
	static inline int genl_set_err(const struct genl_family *family,
	struct net *net, u32 portid,
	u32 group, int code)
	{
	if (WARN_ON_ONCE(group >= family->n_mcgrps))
	return -EINVAL;
	group = family->mcgrp_offset + group;
	return netlink_set_err(net->genl_sock, portid, group, code);
	}

	static inline int genl_has_listeners(const struct genl_family *family,
	struct net *net, unsigned int group)
	{
	if (WARN_ON_ONCE(group >= family->n_mcgrps))
	return -EINVAL;
	group = family->mcgrp_offset + group;
	return netlink_has_listeners(net->genl_sock, group);
	}
	#endif /* __NET_GENERIC_NETLINK_H */