text: /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of version 2 of the GNU General Public
   * License as published by the Free Software Foundation.
   */
  #ifndef _UAPI__LINUX_BPF_H__
  #define _UAPI__LINUX_BPF_H__
  
  #include <linux/types.h>
  #include <linux/bpf_common.h>
  
  /* Extended instruction set based on top of classic BPF */
  
  /* instruction classes */
  #define BPF_ALU64	0x07	/* alu mode in double word width */
  
  /* ld/ldx fields */
  #define BPF_DW		0x18	/* double word */
  #define BPF_XADD	0xc0	/* exclusive add */
  
  /* alu/jmp fields */
  #define BPF_MOV		0xb0	/* mov reg to reg */
  #define BPF_ARSH	0xc0	/* sign extending arithmetic shift right */
  
  /* change endianness of a register */
  #define BPF_END		0xd0	/* flags for endianness conversion: */
  #define BPF_TO_LE	0x00	/* convert to little-endian */
  #define BPF_TO_BE	0x08	/* convert to big-endian */
  #define BPF_FROM_LE	BPF_TO_LE
  #define BPF_FROM_BE	BPF_TO_BE
  
  #define BPF_JNE		0x50	/* jump != */
  #define BPF_JSGT	0x60	/* SGT is signed '>', GT in x86 */
  #define BPF_JSGE	0x70	/* SGE is signed '>=', GE in x86 */
  #define BPF_CALL	0x80	/* function call */
  #define BPF_EXIT	0x90	/* function return */
  
  /* Register numbers */
  enum {
  	BPF_REG_0 = 0,
  	BPF_REG_1,
  	BPF_REG_2,
  	BPF_REG_3,
  	BPF_REG_4,
  	BPF_REG_5,
  	BPF_REG_6,
  	BPF_REG_7,
  	BPF_REG_8,
  	BPF_REG_9,
  	BPF_REG_10,
  	__MAX_BPF_REG,
  };
  
  /* BPF has 10 general purpose 64-bit registers and stack frame. */
  #define MAX_BPF_REG	__MAX_BPF_REG
  
  struct bpf_insn {
  	__u8	code;		/* opcode */
  	__u8	dst_reg:4;	/* dest register */
  	__u8	src_reg:4;	/* source register */
  	__s16	off;		/* signed offset */
  	__s32	imm;		/* signed immediate constant */
  };
  
  /* BPF syscall commands */
  enum bpf_cmd {
  	/* create a map with given type and attributes
  	 * fd = bpf(BPF_MAP_CREATE, union bpf_attr *, u32 size)
  	 * returns fd or negative error
  	 * map is deleted when fd is closed
  	 */
  	BPF_MAP_CREATE,
  
  	/* lookup key in a given map
  	 * err = bpf(BPF_MAP_LOOKUP_ELEM, union bpf_attr *attr, u32 size)
  	 * Using attr->map_fd, attr->key, attr->value
  	 * returns zero and stores found elem into value
  	 * or negative error
  	 */
  	BPF_MAP_LOOKUP_ELEM,
  
  	/* create or update key/value pair in a given map
  	 * err = bpf(BPF_MAP_UPDATE_ELEM, union bpf_attr *attr, u32 size)
  	 * Using attr->map_fd, attr->key, attr->value
  	 * returns zero or negative error
  	 */
  	BPF_MAP_UPDATE_ELEM,
  
  	/* find and delete elem by key in a given map
  	 * err = bpf(BPF_MAP_DELETE_ELEM, union bpf_attr *attr, u32 size)
  	 * Using attr->map_fd, attr->key
  	 * returns zero or negative error
  	 */
  	BPF_MAP_DELETE_ELEM,
  
  	/* lookup key in a given map and return next key
  	 * err = bpf(BPF_MAP_GET_NEXT_KEY, union bpf_attr *attr, u32 size)
  	 * Using attr->map_fd, attr->key, attr->next_key
  	 * returns zero and stores next key or negative error
  	 */
  	BPF_MAP_GET_NEXT_KEY,
  
  	/* verify and load eBPF program
  	 * prog_fd = bpf(BPF_PROG_LOAD, union bpf_attr *attr, u32 size)
  	 * Using attr->prog_type, attr->insns, attr->license
  	 * returns fd or negative error
  	 */
  	BPF_PROG_LOAD,
  };
  
  enum bpf_map_type {
  	BPF_MAP_TYPE_UNSPEC,
  };
  
  enum bpf_prog_type {
  	BPF_PROG_TYPE_UNSPEC,
  };
  
  union bpf_attr {
  	struct { /* anonymous struct used by BPF_MAP_CREATE command */
  		__u32	map_type;	/* one of enum bpf_map_type */
  		__u32	key_size;	/* size of key in bytes */
  		__u32	value_size;	/* size of value in bytes */
  		__u32	max_entries;	/* max number of entries in a map */
  	};
  
  	struct { /* anonymous struct used by BPF_MAP_*_ELEM commands */
  		__u32		map_fd;
  		__aligned_u64	key;
  		union {
  			__aligned_u64 value;
  			__aligned_u64 next_key;
  		};
  	};
  
  	struct { /* anonymous struct used by BPF_PROG_LOAD command */
  		__u32		prog_type;	/* one of enum bpf_prog_type */
  		__u32		insn_cnt;
  		__aligned_u64	insns;
  		__aligned_u64	license;
  		__u32		log_level;	/* verbosity level of verifier */
  		__u32		log_size;	/* size of user buffer */
  		__aligned_u64	log_buf;	/* user supplied buffer */
  	};
  } __attribute__((aligned(8)));
  
  /* integer value in 'imm' field of BPF_CALL instruction selects which helper
   * function eBPF program intends to call
   */
  enum bpf_func_id {
  	BPF_FUNC_unspec,
  	__BPF_FUNC_MAX_ID,
  };
  
  #endif /* _UAPI__LINUX_BPF_H__ */
  