text: /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
  #ifndef _UAPI_X_TABLES_H
  #define _UAPI_X_TABLES_H
  #include <linux/kernel.h>
  #include <linux/types.h>
  
  #define XT_FUNCTION_MAXNAMELEN 30
  #define XT_EXTENSION_MAXNAMELEN 29
  #define XT_TABLE_MAXNAMELEN 32
  
  struct xt_entry_match {
  	union {
  		struct {
  			__u16 match_size;
  
  			/* Used by userspace */
  			char name[XT_EXTENSION_MAXNAMELEN];
  			__u8 revision;
  		} user;
  		struct {
  			__u16 match_size;
  
  			/* Used inside the kernel */
  			struct xt_match *match;
  		} kernel;
  
  		/* Total length */
  		__u16 match_size;
  	} u;
  
  	unsigned char data[0];
  };
  
  struct xt_entry_target {
  	union {
  		struct {
  			__u16 target_size;
  
  			/* Used by userspace */
  			char name[XT_EXTENSION_MAXNAMELEN];
  			__u8 revision;
  		} user;
  		struct {
  			__u16 target_size;
  
  			/* Used inside the kernel */
  			struct xt_target *target;
  		} kernel;
  
  		/* Total length */
  		__u16 target_size;
  	} u;
  
  	unsigned char data[0];
  };
  
  #define XT_TARGET_INIT(__name, __size)					       \
  {									       \
  	.target.u.user = {						       \
  		.target_size	= XT_ALIGN(__size),			       \
  		.name		= __name,				       \
  	},								       \
  }
  
  struct xt_standard_target {
  	struct xt_entry_target target;
  	int verdict;
  };
  
  struct xt_error_target {
  	struct xt_entry_target target;
  	char errorname[XT_FUNCTION_MAXNAMELEN];
  };
  
  /* The argument to IPT_SO_GET_REVISION_*.  Returns highest revision
   * kernel supports, if >= revision. */
  struct xt_get_revision {
  	char name[XT_EXTENSION_MAXNAMELEN];
  	__u8 revision;
  };
  
  /* CONTINUE verdict for targets */
  #define XT_CONTINUE 0xFFFFFFFF
  
  /* For standard target */
  #define XT_RETURN (-NF_REPEAT - 1)
  
  /* this is a dummy structure to find out the alignment requirement for a struct
   * containing all the fundamental data types that are used in ipt_entry,
   * ip6t_entry and arpt_entry.  This sucks, and it is a hack.  It will be my
   * personal pleasure to remove it -HW
   */
  struct _xt_align {
  	__u8 u8;
  	__u16 u16;
  	__u32 u32;
  	__u64 u64;
  };
  
  #define XT_ALIGN(s) __ALIGN_KERNEL((s), __alignof__(struct _xt_align))
  
  /* Standard return verdict, or do jump. */
  #define XT_STANDARD_TARGET ""
  /* Error verdict. */
  #define XT_ERROR_TARGET "ERROR"
  
  #define SET_COUNTER(c,b,p) do { (c).bcnt = (b); (c).pcnt = (p); } while(0)
  #define ADD_COUNTER(c,b,p) do { (c).bcnt += (b); (c).pcnt += (p); } while(0)
  
  struct xt_counters {
  	__u64 pcnt, bcnt;			/* Packet and byte counters */
  };
  
  /* The argument to IPT_SO_ADD_COUNTERS. */
  struct xt_counters_info {
  	/* Which table. */
  	char name[XT_TABLE_MAXNAMELEN];
  
  	unsigned int num_counters;
  
  	/* The counters (actually `number' of these). */
  	struct xt_counters counters[0];
  };
  
  #define XT_INV_PROTO		0x40	/* Invert the sense of PROTO. */
  
  #ifndef __KERNEL__
  /* fn returns 0 to continue iteration */
  #define XT_MATCH_ITERATE(type, e, fn, args...)			\
  ({								\
  	unsigned int __i;					\
  	int __ret = 0;						\
  	struct xt_entry_match *__m;				\
  								\
  	for (__i = sizeof(type);				\
  	     __i < (e)->target_offset;				\
  	     __i += __m->u.match_size) {			\
  		__m = (void *)e + __i;				\
  								\
  		__ret = fn(__m , ## args);			\
  		if (__ret != 0)					\
  			break;					\
  	}							\
  	__ret;							\
  })
  
  /* fn returns 0 to continue iteration */
  #define XT_ENTRY_ITERATE_CONTINUE(type, entries, size, n, fn, args...) \
  ({								\
  	unsigned int __i, __n;					\
  	int __ret = 0;						\
  	type *__entry;						\
  								\
  	for (__i = 0, __n = 0; __i < (size);			\
  	     __i += __entry->next_offset, __n++) { 		\
  		__entry = (void *)(entries) + __i;		\
  		if (__n < n)					\
  			continue;				\
  								\
  		__ret = fn(__entry , ## args);			\
  		if (__ret != 0)					\
  			break;					\
  	}							\
  	__ret;							\
  })
  
  /* fn returns 0 to continue iteration */
  #define XT_ENTRY_ITERATE(type, entries, size, fn, args...) \
  	XT_ENTRY_ITERATE_CONTINUE(type, entries, size, 0, fn, args)
  
  #endif /* !__KERNEL__ */
  
  /* pos is normally a struct ipt_entry/ip6t_entry/etc. */
  #define xt_entry_foreach(pos, ehead, esize) \
  	for ((pos) = (typeof(pos))(ehead); \
  	     (pos) < (typeof(pos))((char *)(ehead) + (esize)); \
  	     (pos) = (typeof(pos))((char *)(pos) + (pos)->next_offset))
  
  /* can only be xt_entry_match, so no use of typeof here */
  #define xt_ematch_foreach(pos, entry) \
  	for ((pos) = (struct xt_entry_match *)entry->elems; \
  	     (pos) < (struct xt_entry_match *)((char *)(entry) + \
  	             (entry)->target_offset); \
  	     (pos) = (struct xt_entry_match *)((char *)(pos) + \
  	             (pos)->u.match_size))
  
  
  #endif /* _UAPI_X_TABLES_H */
  