linux_dsm_epyc7002/include/uapi/linux/bpf.h
Alexei Starovoitov cbd3570086 bpf: verifier (add ability to receive verification log)
add optional attributes for BPF_PROG_LOAD syscall:
union bpf_attr {
    struct {
	...
	__u32         log_level; /* verbosity level of eBPF verifier */
	__u32         log_size;  /* size of user buffer */
	__aligned_u64 log_buf;   /* user supplied 'char *buffer' */
    };
};

when log_level > 0 the verifier will return its verification log in the user
supplied buffer 'log_buf' which can be used by program author to analyze why
verifier rejected given program.

'Understanding eBPF verifier messages' section of Documentation/networking/filter.txt
provides several examples of these messages, like the program:

  BPF_ST_MEM(BPF_DW, BPF_REG_10, -8, 0),
  BPF_MOV64_REG(BPF_REG_2, BPF_REG_10),
  BPF_ALU64_IMM(BPF_ADD, BPF_REG_2, -8),
  BPF_LD_MAP_FD(BPF_REG_1, 0),
  BPF_CALL_FUNC(BPF_FUNC_map_lookup_elem),
  BPF_JMP_IMM(BPF_JEQ, BPF_REG_0, 0, 1),
  BPF_ST_MEM(BPF_DW, BPF_REG_0, 4, 0),
  BPF_EXIT_INSN(),

will be rejected with the following multi-line message in log_buf:

  0: (7a) *(u64 *)(r10 -8) = 0
  1: (bf) r2 = r10
  2: (07) r2 += -8
  3: (b7) r1 = 0
  4: (85) call 1
  5: (15) if r0 == 0x0 goto pc+1
   R0=map_ptr R10=fp
  6: (7a) *(u64 *)(r0 +4) = 0
  misaligned access off 4 size 8

The format of the output can change at any time as verifier evolves.

Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2014-09-26 15:05:15 -04:00

156 lines
4.1 KiB
C

/* 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>
/* 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__ */