libseccomp/tools/bpf.h

   1 /**
   2  * BPF Language Definitions
   3  *
   4  * Copyright (c) 2012 Red Hat <pmoore@redhat.com>
   5  * Author: Paul Moore <paul@paul-moore.com>
   6  */
   7
   8 /*
   9  * This library is free software; you can redistribute it and/or modify it
  10  * under the terms of version 2.1 of the GNU Lesser General Public License as
  11  * published by the Free Software Foundation.
  12  *
  13  * This library is distributed in the hope that it will be useful, but WITHOUT
  14  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
  16  * for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public License
  19  * along with this library; if not, see <http://www.gnu.org/licenses>.
  20  */
  21
  22 #ifndef _BPF_H
  23 #define _BPF_H
  24
  25 #include <inttypes.h>
  26 #include <stddef.h>
  27
  28 /* most of these structures and values are designed to match the Linux Kernel's
  29  * BPF interface (see /usr/include/linux/{filter,seccomp}.h), but we define our
  30  * own here so that we can function independent of the host OS */
  31
  32 /* XXX - need to verify these values */
  33 #define BPF_SCRATCH_SIZE        6
  34
  35 /**
  36  * Syscall record data format used by seccomp
  37  */
  38 #define BPF_SYS_ARG_MAX         6
  39 struct seccomp_data {
  40         int32_t nr;
  41         uint32_t arch;
  42         uint64_t instruction_pointer;
  43         uint64_t args[BPF_SYS_ARG_MAX];
  44 };
  45 #define BPF_SYSCALL_MAX         (sizeof(struct seccomp_data))
  46
  47 /**
  48  * BPF instruction format
  49  */
  50 struct sock_filter {
  51         uint16_t code;
  52         uint8_t jt;
  53         uint8_t jf;
  54         uint32_t k;
  55 } __attribute__ ((packed));
  56 typedef struct sock_filter bpf_instr_raw;
  57
  58 /* seccomp return masks */
  59 #define SECCOMP_RET_ACTION      0x7fff0000U
  60 #define SECCOMP_RET_DATA        0x0000ffffU
  61
  62 /* seccomp action values */
  63 #define SECCOMP_RET_KILL        0x00000000U
  64 #define SECCOMP_RET_TRAP        0x00030000U
  65 #define SECCOMP_RET_ERRNO       0x00050000U
  66 #define SECCOMP_RET_TRACE       0x7ff00000U
  67 #define SECCOMP_RET_ALLOW       0x7fff0000U
  68
  69 /* bpf command classes */
  70 #define BPF_CLASS(code)         ((code) & 0x07)
  71 #define BPF_LD                  0x00
  72 #define BPF_LDX                 0x01
  73 #define BPF_ST                  0x02
  74 #define BPF_STX                 0x03
  75 #define BPF_ALU                 0x04
  76 #define BPF_JMP                 0x05
  77 #define BPF_RET                 0x06
  78 #define BPF_MISC                0x07
  79
  80 /* BPF_LD and BPF_LDX */
  81 #define BPF_SIZE(code)          ((code) & 0x18)
  82 #define BPF_W                   0x00
  83 #define BPF_H                   0x08
  84 #define BPF_B                   0x10
  85 #define BPF_MODE(code)          ((code) & 0xe0)
  86 #define BPF_IMM                 0x00
  87 #define BPF_ABS                 0x20
  88 #define BPF_IND                 0x40
  89 #define BPF_MEM                 0x60
  90 #define BPF_LEN                 0x80
  91 #define BPF_MSH                 0xa0
  92
  93 #define BPF_OP(code)            ((code) & 0xf0)
  94 /* BPF_ALU */
  95 #define BPF_ADD                 0x00
  96 #define BPF_SUB                 0x10
  97 #define BPF_MUL                 0x20
  98 #define BPF_DIV                 0x30
  99 #define BPF_OR                  0x40
 100 #define BPF_AND                 0x50
 101 #define BPF_LSH                 0x60
 102 #define BPF_RSH                 0x70
 103 #define BPF_NEG                 0x80
 104 /* BPF_JMP */
 105 #define BPF_JA                  0x00
 106 #define BPF_JEQ                 0x10
 107 #define BPF_JGT                 0x20
 108 #define BPF_JGE                 0x30
 109 #define BPF_JSET                0x40
 110
 111 #define BPF_SRC(code)           ((code) & 0x08)
 112 #define BPF_K                   0x00
 113 #define BPF_X                   0x08
 114
 115 /* BPF_RET (BPF_K and BPF_X also apply) */
 116 #define BPF_RVAL(code)          ((code) & 0x18)
 117 #define BPF_A                   0x10
 118
 119 /* BPF_MISC */
 120 #define BPF_MISCOP(code)        ((code) & 0xf8)
 121 #define BPF_TAX                 0x00
 122 #define BPF_TXA                 0x80
 123
 124 #endif