src/shared/linux/libbpf.h

/* eBPF mini library */
#ifndef __LIBBPF_H
#define __LIBBPF_H

#include <linux/bpf.h>

struct bpf_insn;

/* ALU ops on registers, bpf_add|sub|...: dst_reg += src_reg */

#define BPF_ALU64_REG(OP, DST, SRC)				\
        ((struct bpf_insn) {					\
                .code  = BPF_ALU64 | BPF_OP(OP) | BPF_X,	\
                .dst_reg = DST,					\
                .src_reg = SRC,					\
                .off   = 0,					\
                .imm   = 0 })

#define BPF_ALU32_REG(OP, DST, SRC)				\
        ((struct bpf_insn) {					\
                .code  = BPF_ALU | BPF_OP(OP) | BPF_X,		\
                .dst_reg = DST,					\
                .src_reg = SRC,					\
                .off   = 0,					\
                .imm   = 0 })

/* ALU ops on immediates, bpf_add|sub|...: dst_reg += imm32 */

#define BPF_ALU64_IMM(OP, DST, IMM)				\
        ((struct bpf_insn) {					\
                .code  = BPF_ALU64 | BPF_OP(OP) | BPF_K,	\
                .dst_reg = DST,					\
                .src_reg = 0,					\
                .off   = 0,					\
                .imm   = IMM })

#define BPF_ALU32_IMM(OP, DST, IMM)				\
        ((struct bpf_insn) {					\
                .code  = BPF_ALU | BPF_OP(OP) | BPF_K,		\
                .dst_reg = DST,					\
                .src_reg = 0,					\
                .off   = 0,					\
                .imm   = IMM })

/* Short form of mov, dst_reg = src_reg */

#define BPF_MOV64_REG(DST, SRC)					\
        ((struct bpf_insn) {					\
                .code  = BPF_ALU64 | BPF_MOV | BPF_X,		\
                .dst_reg = DST,					\
                .src_reg = SRC,					\
                .off   = 0,					\
                .imm   = 0 })

#define BPF_MOV32_REG(DST, SRC)					\
        ((struct bpf_insn) {					\
                .code  = BPF_ALU | BPF_MOV | BPF_X,		\
                .dst_reg = DST,					\
                .src_reg = SRC,					\
                .off   = 0,					\
                .imm   = 0 })

/* Short form of mov, dst_reg = imm32 */

#define BPF_MOV64_IMM(DST, IMM)					\
        ((struct bpf_insn) {					\
                .code  = BPF_ALU64 | BPF_MOV | BPF_K,		\
                .dst_reg = DST,					\
                .src_reg = 0,					\
                .off   = 0,					\
                .imm   = IMM })

#define BPF_MOV32_IMM(DST, IMM)					\
        ((struct bpf_insn) {					\
                .code  = BPF_ALU | BPF_MOV | BPF_K,		\
                .dst_reg = DST,					\
                .src_reg = 0,					\
                .off   = 0,					\
                .imm   = IMM })

/* BPF_LD_IMM64 macro encodes single 'load 64-bit immediate' insn */
#define BPF_LD_IMM64(DST, IMM)					\
        BPF_LD_IMM64_RAW(DST, 0, IMM)

#define BPF_LD_IMM64_RAW(DST, SRC, IMM)				\
        ((struct bpf_insn) {					\
                .code  = BPF_LD | BPF_DW | BPF_IMM,		\
                .dst_reg = DST,					\
                .src_reg = SRC,					\
                .off   = 0,					\
                .imm   = (__u32) (IMM) }),			\
        ((struct bpf_insn) {					\
                .code  = 0, /* zero is reserved opcode */	\
                .dst_reg = 0,					\
                .src_reg = 0,					\
                .off   = 0,					\
                .imm   = ((__u64) (IMM)) >> 32 })

#ifndef BPF_PSEUDO_MAP_FD
# define BPF_PSEUDO_MAP_FD	1
#endif

/* pseudo BPF_LD_IMM64 insn used to refer to process-local map_fd */
#define BPF_LD_MAP_FD(DST, MAP_FD)				\
        BPF_LD_IMM64_RAW(DST, BPF_PSEUDO_MAP_FD, MAP_FD)

/* Direct packet access, R0 = *(uint *) (skb->data + imm32) */

#define BPF_LD_ABS(SIZE, IMM)					\
        ((struct bpf_insn) {					\
                .code  = BPF_LD | BPF_SIZE(SIZE) | BPF_ABS,	\
                .dst_reg = 0,					\
                .src_reg = 0,					\
                .off   = 0,					\
                .imm   = IMM })

/* Memory load, dst_reg = *(uint *) (src_reg + off16) */

#define BPF_LDX_MEM(SIZE, DST, SRC, OFF)			\
        ((struct bpf_insn) {					\
                .code  = BPF_LDX | BPF_SIZE(SIZE) | BPF_MEM,	\
                .dst_reg = DST,					\
                .src_reg = SRC,					\
                .off   = OFF,					\
                .imm   = 0 })

/* Memory store, *(uint *) (dst_reg + off16) = src_reg */

#define BPF_STX_MEM(SIZE, DST, SRC, OFF)			\
        ((struct bpf_insn) {					\
                .code  = BPF_STX | BPF_SIZE(SIZE) | BPF_MEM,	\
                .dst_reg = DST,					\
                .src_reg = SRC,					\
                .off   = OFF,					\
                .imm   = 0 })

/* Atomic memory add, *(uint *)(dst_reg + off16) += src_reg */

#define BPF_STX_XADD(SIZE, DST, SRC, OFF)			\
        ((struct bpf_insn) {					\
                .code  = BPF_STX | BPF_SIZE(SIZE) | BPF_XADD,	\
                .dst_reg = DST,					\
                .src_reg = SRC,					\
                .off   = OFF,					\
                .imm   = 0 })

/* Memory store, *(uint *) (dst_reg + off16) = imm32 */

#define BPF_ST_MEM(SIZE, DST, OFF, IMM)				\
        ((struct bpf_insn) {					\
                .code  = BPF_ST | BPF_SIZE(SIZE) | BPF_MEM,	\
                .dst_reg = DST,					\
                .src_reg = 0,					\
                .off   = OFF,					\
                .imm   = IMM })

/* Conditional jumps against registers, if (dst_reg 'op' src_reg) goto pc + off16 */

#define BPF_JMP_REG(OP, DST, SRC, OFF)				\
        ((struct bpf_insn) {					\
                .code  = BPF_JMP | BPF_OP(OP) | BPF_X,		\
                .dst_reg = DST,					\
                .src_reg = SRC,					\
                .off   = OFF,					\
                .imm   = 0 })

/* Conditional jumps against immediates, if (dst_reg 'op' imm32) goto pc + off16 */

#define BPF_JMP_IMM(OP, DST, IMM, OFF)				\
        ((struct bpf_insn) {					\
                .code  = BPF_JMP | BPF_OP(OP) | BPF_K,		\
                .dst_reg = DST,					\
                .src_reg = 0,					\
                .off   = OFF,					\
                .imm   = IMM })

/* Unconditional jumps */

#define BPF_JMP_A(OFF)						\
        ((struct bpf_insn) {					\
                .code  = BPF_JMP | BPF_JA,			\
                .dst_reg = 0,					\
                .src_reg = 0,					\
                .off   = OFF,					\
                .imm   = 0 })

/* Raw code statement block */

#define BPF_RAW_INSN(CODE, DST, SRC, OFF, IMM)			\
        ((struct bpf_insn) {					\
                .code  = CODE,					\
                .dst_reg = DST,					\
                .src_reg = SRC,					\
                .off   = OFF,					\
                .imm   = IMM })

/* Program exit */

#define BPF_EXIT_INSN()						\
        ((struct bpf_insn) {					\
                .code  = BPF_JMP | BPF_EXIT,			\
                .dst_reg = 0,					\
                .src_reg = 0,					\
                .off   = 0,					\
                .imm   = 0 })

#endif