include/uapi/linux/bpf.h

   1 /* Copyright (c) 2011-2014 PLUMgrid, http://plumgrid.com
   2  *
   3  * This program is free software; you can redistribute it and/or
   4  * modify it under the terms of version 2 of the GNU General Public
   5  * License as published by the Free Software Foundation.
   6  */
   7 #ifndef _UAPI__LINUX_BPF_H__
   8 #define _UAPI__LINUX_BPF_H__
   9
  10 #include <linux/types.h>
  11
  12 /* Extended instruction set based on top of classic BPF */
  13
  14 /* instruction classes */
  15 #define BPF_ALU64       0x07    /* alu mode in double word width */
  16
  17 /* ld/ldx fields */
  18 #define BPF_DW          0x18    /* double word */
  19 #define BPF_XADD        0xc0    /* exclusive add */
  20
  21 /* alu/jmp fields */
  22 #define BPF_MOV         0xb0    /* mov reg to reg */
  23 #define BPF_ARSH        0xc0    /* sign extending arithmetic shift right */
  24
  25 /* change endianness of a register */
  26 #define BPF_END         0xd0    /* flags for endianness conversion: */
  27 #define BPF_TO_LE       0x00    /* convert to little-endian */
  28 #define BPF_TO_BE       0x08    /* convert to big-endian */
  29 #define BPF_FROM_LE     BPF_TO_LE
  30 #define BPF_FROM_BE     BPF_TO_BE
  31
  32 #define BPF_JNE         0x50    /* jump != */
  33 #define BPF_JSGT        0x60    /* SGT is signed '>', GT in x86 */
  34 #define BPF_JSGE        0x70    /* SGE is signed '>=', GE in x86 */
  35 #define BPF_CALL        0x80    /* function call */
  36 #define BPF_EXIT        0x90    /* function return */
  37
  38 /* Register numbers */
  39 enum {
  40         BPF_REG_0 = 0,
  41         BPF_REG_1,
  42         BPF_REG_2,
  43         BPF_REG_3,
  44         BPF_REG_4,
  45         BPF_REG_5,
  46         BPF_REG_6,
  47         BPF_REG_7,
  48         BPF_REG_8,
  49         BPF_REG_9,
  50         BPF_REG_10,
  51         __MAX_BPF_REG,
  52 };
  53
  54 /* BPF has 10 general purpose 64-bit registers and stack frame. */
  55 #define MAX_BPF_REG     __MAX_BPF_REG
  56
  57 struct bpf_insn {
  58         __u8    code;           /* opcode */
  59         __u8    dst_reg:4;      /* dest register */
  60         __u8    src_reg:4;      /* source register */
  61         __s16   off;            /* signed offset */
  62         __s32   imm;            /* signed immediate constant */
  63 };
  64
  65 /* BPF syscall commands */
  66 enum bpf_cmd {
  67         /* create a map with given type and attributes
  68          * fd = bpf(BPF_MAP_CREATE, union bpf_attr *, u32 size)
  69          * returns fd or negative error
  70          * map is deleted when fd is closed
  71          */
  72         BPF_MAP_CREATE,
  73
  74         /* lookup key in a given map
  75          * err = bpf(BPF_MAP_LOOKUP_ELEM, union bpf_attr *attr, u32 size)
  76          * Using attr->map_fd, attr->key, attr->value
  77          * returns zero and stores found elem into value
  78          * or negative error
  79          */
  80         BPF_MAP_LOOKUP_ELEM,
  81
  82         /* create or update key/value pair in a given map
  83          * err = bpf(BPF_MAP_UPDATE_ELEM, union bpf_attr *attr, u32 size)
  84          * Using attr->map_fd, attr->key, attr->value
  85          * returns zero or negative error
  86          */
  87         BPF_MAP_UPDATE_ELEM,
  88
  89         /* find and delete elem by key in a given map
  90          * err = bpf(BPF_MAP_DELETE_ELEM, union bpf_attr *attr, u32 size)
  91          * Using attr->map_fd, attr->key
  92          * returns zero or negative error
  93          */
  94         BPF_MAP_DELETE_ELEM,
  95
  96         /* lookup key in a given map and return next key
  97          * err = bpf(BPF_MAP_GET_NEXT_KEY, union bpf_attr *attr, u32 size)
  98          * Using attr->map_fd, attr->key, attr->next_key
  99          * returns zero and stores next key or negative error
 100          */
 101         BPF_MAP_GET_NEXT_KEY,
 102 };
 103
 104 enum bpf_map_type {
 105         BPF_MAP_TYPE_UNSPEC,
 106 };
 107
 108 union bpf_attr {
 109         struct { /* anonymous struct used by BPF_MAP_CREATE command */
 110                 __u32   map_type;       /* one of enum bpf_map_type */
 111                 __u32   key_size;       /* size of key in bytes */
 112                 __u32   value_size;     /* size of value in bytes */
 113                 __u32   max_entries;    /* max number of entries in a map */
 114         };
 115
 116         struct { /* anonymous struct used by BPF_MAP_*_ELEM commands */
 117                 __u32           map_fd;
 118                 __aligned_u64   key;
 119                 union {
 120                         __aligned_u64 value;
 121                         __aligned_u64 next_key;
 122                 };
 123         };
 124 } __attribute__((aligned(8)));
 125
 126 #endif /* _UAPI__LINUX_BPF_H__ */