/* SPDX-License-Identifier: GPL-2.0 */

  #ifndef __LINUX_NETLINK_H
  #define __LINUX_NETLINK_H

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

  #include <linux/export.h>

  #include <net/scm.h>

  #include <uapi/linux/netlink.h>

  struct net;

  static inline struct nlmsghdr *nlmsg_hdr(const struct sk_buff *skb)
  {
  	return (struct nlmsghdr *)skb->data;
  }

  enum netlink_skb_flags {

  	NETLINK_SKB_DST		= 0x8,	/* Dst set in sendto or sendmsg */

  };

  struct netlink_skb_parms {

  	struct scm_creds	creds;		/* Skb credentials	*/

  	__u32			portid;

  	__u32			dst_group;

  	__u32			flags;

  	struct sock		*sk;

  	bool			nsid_is_set;
  	int			nsid;

  };
  
  #define NETLINK_CB(skb)		(*(struct netlink_skb_parms*)&((skb)->cb))
  #define NETLINK_CREDS(skb)	(&NETLINK_CB((skb)).creds)

  void netlink_table_grab(void);
  void netlink_table_ungrab(void);

  #define NL_CFG_F_NONROOT_RECV	(1 << 0)
  #define NL_CFG_F_NONROOT_SEND	(1 << 1)

  /* optional Netlink kernel configuration parameters */
  struct netlink_kernel_cfg {
  	unsigned int	groups;

  	unsigned int	flags;

  	void		(*input)(struct sk_buff *skb);
  	struct mutex	*cb_mutex;

  	int		(*bind)(struct net *net, int group);
  	void		(*unbind)(struct net *net, int group);

  	bool		(*compare)(struct net *net, struct sock *sk);

  };

  struct sock *__netlink_kernel_create(struct net *net, int unit,

  					    struct module *module,
  					    struct netlink_kernel_cfg *cfg);
  static inline struct sock *
  netlink_kernel_create(struct net *net, int unit, struct netlink_kernel_cfg *cfg)
  {
  	return __netlink_kernel_create(net, unit, THIS_MODULE, cfg);
  }

  /* this can be increased when necessary - don't expose to userland */
  #define NETLINK_MAX_COOKIE_LEN	20

  /**
   * struct netlink_ext_ack - netlink extended ACK report struct
   * @_msg: message string to report - don't access directly, use
   *	%NL_SET_ERR_MSG
   * @bad_attr: attribute with error

   * @policy: policy for a bad attribute

   * @cookie: cookie data to return to userspace (for success)
   * @cookie_len: actual cookie data length

   */
  struct netlink_ext_ack {
  	const char *_msg;
  	const struct nlattr *bad_attr;

  	const struct nla_policy *policy;

  	u8 cookie[NETLINK_MAX_COOKIE_LEN];
  	u8 cookie_len;

  };
  
  /* Always use this macro, this allows later putting the
   * message into a separate section or such for things
   * like translation or listing all possible messages.
   * Currently string formatting is not supported (due
   * to the lack of an output buffer.)
   */

  #define NL_SET_ERR_MSG(extack, msg) do {		\

  	static const char __msg[] = msg;		\

  	struct netlink_ext_ack *__extack = (extack);	\
  							\
  	if (__extack)					\
  		__extack->_msg = __msg;			\

  } while (0)

  #define NL_SET_ERR_MSG_MOD(extack, msg)			\
  	NL_SET_ERR_MSG((extack), KBUILD_MODNAME ": " msg)

  #define NL_SET_BAD_ATTR_POLICY(extack, attr, pol) do {	\
  	if ((extack)) {					\

  		(extack)->bad_attr = (attr);		\

  		(extack)->policy = (pol);		\
  	}						\

  } while (0)

  #define NL_SET_BAD_ATTR(extack, attr) NL_SET_BAD_ATTR_POLICY(extack, attr, NULL)
  
  #define NL_SET_ERR_MSG_ATTR_POL(extack, attr, pol, msg) do {	\
  	static const char __msg[] = msg;			\
  	struct netlink_ext_ack *__extack = (extack);		\
  								\
  	if (__extack) {						\
  		__extack->_msg = __msg;				\
  		__extack->bad_attr = (attr);			\
  		__extack->policy = (pol);			\
  	}							\

  } while (0)

  #define NL_SET_ERR_MSG_ATTR(extack, attr, msg)		\
  	NL_SET_ERR_MSG_ATTR_POL(extack, attr, NULL, msg)

  static inline void nl_set_extack_cookie_u64(struct netlink_ext_ack *extack,
  					    u64 cookie)
  {
  	u64 __cookie = cookie;

  	if (!extack)
  		return;

  	memcpy(extack->cookie, &__cookie, sizeof(__cookie));
  	extack->cookie_len = sizeof(__cookie);
  }

  static inline void nl_set_extack_cookie_u32(struct netlink_ext_ack *extack,
  					    u32 cookie)
  {
  	u32 __cookie = cookie;

  	if (!extack)
  		return;

  	memcpy(extack->cookie, &__cookie, sizeof(__cookie));
  	extack->cookie_len = sizeof(__cookie);
  }

  void netlink_kernel_release(struct sock *sk);
  int __netlink_change_ngroups(struct sock *sk, unsigned int groups);
  int netlink_change_ngroups(struct sock *sk, unsigned int groups);
  void __netlink_clear_multicast_users(struct sock *sk, unsigned int group);
  void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err,
  		 const struct netlink_ext_ack *extack);
  int netlink_has_listeners(struct sock *sk, unsigned int group);

  bool netlink_strict_get_check(struct sk_buff *skb);

  
  int netlink_unicast(struct sock *ssk, struct sk_buff *skb, __u32 portid, int nonblock);
  int netlink_broadcast(struct sock *ssk, struct sk_buff *skb, __u32 portid,
  		      __u32 group, gfp_t allocation);
  int netlink_broadcast_filtered(struct sock *ssk, struct sk_buff *skb,
  			       __u32 portid, __u32 group, gfp_t allocation,
  			       int (*filter)(struct sock *dsk, struct sk_buff *skb, void *data),
  			       void *filter_data);
  int netlink_set_err(struct sock *ssk, __u32 portid, __u32 group, int code);
  int netlink_register_notifier(struct notifier_block *nb);
  int netlink_unregister_notifier(struct notifier_block *nb);

  
  /* finegrained unicast helpers: */
  struct sock *netlink_getsockbyfilp(struct file *filp);

  int netlink_attachskb(struct sock *sk, struct sk_buff *skb,

  		      long *timeo, struct sock *ssk);

  void netlink_detachskb(struct sock *sk, struct sk_buff *skb);

  int netlink_sendskb(struct sock *sk, struct sk_buff *skb);

  static inline struct sk_buff *
  netlink_skb_clone(struct sk_buff *skb, gfp_t gfp_mask)
  {
  	struct sk_buff *nskb;
  
  	nskb = skb_clone(skb, gfp_mask);
  	if (!nskb)
  		return NULL;
  
  	/* This is a large skb, set destructor callback to release head */
  	if (is_vmalloc_addr(skb->head))
  		nskb->destructor = skb->destructor;
  
  	return nskb;
  }

  /*
   *	skb should fit one page. This choice is good for headerless malloc.

   *	But we should limit to 8K so that userspace does not have to
   *	use enormous buffer sizes on recvmsg() calls just to avoid
   *	MSG_TRUNC when PAGE_SIZE is very large.

   */

  #if PAGE_SIZE < 8192UL
  #define NLMSG_GOODSIZE	SKB_WITH_OVERHEAD(PAGE_SIZE)
  #else
  #define NLMSG_GOODSIZE	SKB_WITH_OVERHEAD(8192UL)
  #endif

  #define NLMSG_DEFAULT_SIZE (NLMSG_GOODSIZE - NLMSG_HDRLEN)

  struct netlink_callback {

  	struct sk_buff		*skb;
  	const struct nlmsghdr	*nlh;
  	int			(*dump)(struct sk_buff * skb,
  					struct netlink_callback *cb);
  	int			(*done)(struct netlink_callback *cb);

  	void			*data;

  	/* the module that dump function belong to */
  	struct module		*module;

  	struct netlink_ext_ack	*extack;

  	u16			family;

  	u16			answer_flags;

  	u32			min_dump_alloc;

  	unsigned int		prev_seq, seq;

  	bool			strict_check;

  	union {
  		u8		ctx[48];
  
  		/* args is deprecated. Cast a struct over ctx instead
  		 * for proper type safety.
  		 */
  		long		args[6];
  	};

  };

  struct netlink_notify {

  	struct net *net;

  	u32 portid;

  	int protocol;
  };

  struct nlmsghdr *

  __nlmsg_put(struct sk_buff *skb, u32 portid, u32 seq, int type, int len, int flags);

  struct netlink_dump_control {

  	int (*start)(struct netlink_callback *);

  	int (*dump)(struct sk_buff *skb, struct netlink_callback *);

  	int (*done)(struct netlink_callback *);

  	void *data;

  	struct module *module;

  	u32 min_dump_alloc;

  };

  int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb,

  				const struct nlmsghdr *nlh,
  				struct netlink_dump_control *control);
  static inline int netlink_dump_start(struct sock *ssk, struct sk_buff *skb,
  				     const struct nlmsghdr *nlh,
  				     struct netlink_dump_control *control)
  {
  	if (!control->module)
  		control->module = THIS_MODULE;
  
  	return __netlink_dump_start(ssk, skb, nlh, control);
  }

  struct netlink_tap {
  	struct net_device *dev;
  	struct module *module;
  	struct list_head list;
  };

  int netlink_add_tap(struct netlink_tap *nt);
  int netlink_remove_tap(struct netlink_tap *nt);

  bool __netlink_ns_capable(const struct netlink_skb_parms *nsp,
  			  struct user_namespace *ns, int cap);
  bool netlink_ns_capable(const struct sk_buff *skb,
  			struct user_namespace *ns, int cap);
  bool netlink_capable(const struct sk_buff *skb, int cap);
  bool netlink_net_capable(const struct sk_buff *skb, int cap);

  #endif	/* __LINUX_NETLINK_H */