filter.h 26.5 KB
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/* SPDX-License-Identifier: GPL-2.0 */
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Linus Torvalds 已提交
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/*
 * Linux Socket Filter Data Structures
 */
#ifndef __LINUX_FILTER_H__
#define __LINUX_FILTER_H__

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#include <stdarg.h>

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Arun Sharma 已提交
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#include <linux/atomic.h>
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#include <linux/refcount.h>
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#include <linux/compat.h>
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#include <linux/skbuff.h>
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#include <linux/linkage.h>
#include <linux/printk.h>
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#include <linux/workqueue.h>
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#include <linux/sched.h>
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#include <linux/capability.h>
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#include <linux/cryptohash.h>
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#include <linux/set_memory.h>
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#include <net/sch_generic.h>
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#include <uapi/linux/filter.h>
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#include <uapi/linux/bpf.h>
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struct sk_buff;
struct sock;
struct seccomp_data;
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struct bpf_prog_aux;
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/* ArgX, context and stack frame pointer register positions. Note,
 * Arg1, Arg2, Arg3, etc are used as argument mappings of function
 * calls in BPF_CALL instruction.
 */
#define BPF_REG_ARG1	BPF_REG_1
#define BPF_REG_ARG2	BPF_REG_2
#define BPF_REG_ARG3	BPF_REG_3
#define BPF_REG_ARG4	BPF_REG_4
#define BPF_REG_ARG5	BPF_REG_5
#define BPF_REG_CTX	BPF_REG_6
#define BPF_REG_FP	BPF_REG_10

/* Additional register mappings for converted user programs. */
#define BPF_REG_A	BPF_REG_0
#define BPF_REG_X	BPF_REG_7
#define BPF_REG_TMP	BPF_REG_8
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/* Kernel hidden auxiliary/helper register for hardening step.
 * Only used by eBPF JITs. It's nothing more than a temporary
 * register that JITs use internally, only that here it's part
 * of eBPF instructions that have been rewritten for blinding
 * constants. See JIT pre-step in bpf_jit_blind_constants().
 */
#define BPF_REG_AX		MAX_BPF_REG
#define MAX_BPF_JIT_REG		(MAX_BPF_REG + 1)

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/* unused opcode to mark special call to bpf_tail_call() helper */
#define BPF_TAIL_CALL	0xf0

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/* As per nm, we expose JITed images as text (code) section for
 * kallsyms. That way, tools like perf can find it to match
 * addresses.
 */
#define BPF_SYM_ELF_TYPE	't'

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/* BPF program can access up to 512 bytes of stack space. */
#define MAX_BPF_STACK	512

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/* Helper macros for filter block array initializers. */

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/* ALU ops on registers, bpf_add|sub|...: dst_reg += src_reg */
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#define BPF_ALU64_REG(OP, DST, SRC)				\
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	((struct bpf_insn) {					\
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		.code  = BPF_ALU64 | BPF_OP(OP) | BPF_X,	\
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		.dst_reg = DST,					\
		.src_reg = SRC,					\
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		.off   = 0,					\
		.imm   = 0 })

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

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/* ALU ops on immediates, bpf_add|sub|...: dst_reg += imm32 */
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#define BPF_ALU64_IMM(OP, DST, IMM)				\
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	((struct bpf_insn) {					\
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		.code  = BPF_ALU64 | BPF_OP(OP) | BPF_K,	\
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		.dst_reg = DST,					\
		.src_reg = 0,					\
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		.off   = 0,					\
		.imm   = IMM })

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

/* Endianess conversion, cpu_to_{l,b}e(), {l,b}e_to_cpu() */

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#define BPF_ENDIAN(TYPE, DST, LEN)				\
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	((struct bpf_insn) {					\
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		.code  = BPF_ALU | BPF_END | BPF_SRC(TYPE),	\
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		.dst_reg = DST,					\
		.src_reg = 0,					\
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		.off   = 0,					\
		.imm   = LEN })

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

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

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/* Short form of mov, dst_reg = imm32 */
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#define BPF_MOV64_IMM(DST, IMM)					\
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	((struct bpf_insn) {					\
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		.code  = BPF_ALU64 | BPF_MOV | BPF_K,		\
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		.dst_reg = DST,					\
		.src_reg = 0,					\
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		.off   = 0,					\
		.imm   = IMM })

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

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/* 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 })

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/* 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)

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/* Short form of mov based on type, BPF_X: dst_reg = src_reg, BPF_K: dst_reg = imm32 */
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#define BPF_MOV64_RAW(TYPE, DST, SRC, IMM)			\
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	((struct bpf_insn) {					\
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		.code  = BPF_ALU64 | BPF_MOV | BPF_SRC(TYPE),	\
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		.dst_reg = DST,					\
		.src_reg = SRC,					\
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		.off   = 0,					\
		.imm   = IMM })

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#define BPF_MOV32_RAW(TYPE, DST, SRC, IMM)			\
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	((struct bpf_insn) {					\
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		.code  = BPF_ALU | BPF_MOV | BPF_SRC(TYPE),	\
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		.dst_reg = DST,					\
		.src_reg = SRC,					\
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		.off   = 0,					\
		.imm   = IMM })

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/* Direct packet access, R0 = *(uint *) (skb->data + imm32) */
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#define BPF_LD_ABS(SIZE, IMM)					\
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	((struct bpf_insn) {					\
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		.code  = BPF_LD | BPF_SIZE(SIZE) | BPF_ABS,	\
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		.dst_reg = 0,					\
		.src_reg = 0,					\
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		.off   = 0,					\
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		.imm   = IMM })
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/* Indirect packet access, R0 = *(uint *) (skb->data + src_reg + imm32) */
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#define BPF_LD_IND(SIZE, SRC, IMM)				\
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	((struct bpf_insn) {					\
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		.code  = BPF_LD | BPF_SIZE(SIZE) | BPF_IND,	\
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		.dst_reg = 0,					\
		.src_reg = SRC,					\
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		.off   = 0,					\
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		.imm   = IMM })
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/* Memory load, dst_reg = *(uint *) (src_reg + off16) */
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#define BPF_LDX_MEM(SIZE, DST, SRC, OFF)			\
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	((struct bpf_insn) {					\
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		.code  = BPF_LDX | BPF_SIZE(SIZE) | BPF_MEM,	\
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		.dst_reg = DST,					\
		.src_reg = SRC,					\
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		.off   = OFF,					\
		.imm   = 0 })

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

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

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/* 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 })

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

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

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/* Conditional jumps against immediates, if (dst_reg 'op' imm32) goto pc + off16 */
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#define BPF_JMP_IMM(OP, DST, IMM, OFF)				\
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	((struct bpf_insn) {					\
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		.code  = BPF_JMP | BPF_OP(OP) | BPF_K,		\
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		.dst_reg = DST,					\
		.src_reg = 0,					\
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		.off   = OFF,					\
		.imm   = IMM })

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/* Unconditional jumps, goto pc + off16 */

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

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/* Function call */

#define BPF_EMIT_CALL(FUNC)					\
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	((struct bpf_insn) {					\
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		.code  = BPF_JMP | BPF_CALL,			\
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		.dst_reg = 0,					\
		.src_reg = 0,					\
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		.off   = 0,					\
		.imm   = ((FUNC) - __bpf_call_base) })

/* Raw code statement block */

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

/* Program exit */

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

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/* Internal classic blocks for direct assignment */

#define __BPF_STMT(CODE, K)					\
	((struct sock_filter) BPF_STMT(CODE, K))

#define __BPF_JUMP(CODE, K, JT, JF)				\
	((struct sock_filter) BPF_JUMP(CODE, K, JT, JF))

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#define bytes_to_bpf_size(bytes)				\
({								\
	int bpf_size = -EINVAL;					\
								\
	if (bytes == sizeof(u8))				\
		bpf_size = BPF_B;				\
	else if (bytes == sizeof(u16))				\
		bpf_size = BPF_H;				\
	else if (bytes == sizeof(u32))				\
		bpf_size = BPF_W;				\
	else if (bytes == sizeof(u64))				\
		bpf_size = BPF_DW;				\
								\
	bpf_size;						\
})
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#define bpf_size_to_bytes(bpf_size)				\
({								\
	int bytes = -EINVAL;					\
								\
	if (bpf_size == BPF_B)					\
		bytes = sizeof(u8);				\
	else if (bpf_size == BPF_H)				\
		bytes = sizeof(u16);				\
	else if (bpf_size == BPF_W)				\
		bytes = sizeof(u32);				\
	else if (bpf_size == BPF_DW)				\
		bytes = sizeof(u64);				\
								\
	bytes;							\
})

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#define BPF_SIZEOF(type)					\
	({							\
		const int __size = bytes_to_bpf_size(sizeof(type)); \
		BUILD_BUG_ON(__size < 0);			\
		__size;						\
	})

#define BPF_FIELD_SIZEOF(type, field)				\
	({							\
		const int __size = bytes_to_bpf_size(FIELD_SIZEOF(type, field)); \
		BUILD_BUG_ON(__size < 0);			\
		__size;						\
	})

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#define BPF_LDST_BYTES(insn)					\
	({							\
		const int __size = bpf_size_to_bytes(BPF_SIZE(insn->code)); \
		WARN_ON(__size < 0);				\
		__size;						\
	})

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#define __BPF_MAP_0(m, v, ...) v
#define __BPF_MAP_1(m, v, t, a, ...) m(t, a)
#define __BPF_MAP_2(m, v, t, a, ...) m(t, a), __BPF_MAP_1(m, v, __VA_ARGS__)
#define __BPF_MAP_3(m, v, t, a, ...) m(t, a), __BPF_MAP_2(m, v, __VA_ARGS__)
#define __BPF_MAP_4(m, v, t, a, ...) m(t, a), __BPF_MAP_3(m, v, __VA_ARGS__)
#define __BPF_MAP_5(m, v, t, a, ...) m(t, a), __BPF_MAP_4(m, v, __VA_ARGS__)

#define __BPF_REG_0(...) __BPF_PAD(5)
#define __BPF_REG_1(...) __BPF_MAP(1, __VA_ARGS__), __BPF_PAD(4)
#define __BPF_REG_2(...) __BPF_MAP(2, __VA_ARGS__), __BPF_PAD(3)
#define __BPF_REG_3(...) __BPF_MAP(3, __VA_ARGS__), __BPF_PAD(2)
#define __BPF_REG_4(...) __BPF_MAP(4, __VA_ARGS__), __BPF_PAD(1)
#define __BPF_REG_5(...) __BPF_MAP(5, __VA_ARGS__)

#define __BPF_MAP(n, ...) __BPF_MAP_##n(__VA_ARGS__)
#define __BPF_REG(n, ...) __BPF_REG_##n(__VA_ARGS__)

#define __BPF_CAST(t, a)						       \
	(__force t)							       \
	(__force							       \
	 typeof(__builtin_choose_expr(sizeof(t) == sizeof(unsigned long),      \
				      (unsigned long)0, (t)0))) a
#define __BPF_V void
#define __BPF_N

#define __BPF_DECL_ARGS(t, a) t   a
#define __BPF_DECL_REGS(t, a) u64 a

#define __BPF_PAD(n)							       \
	__BPF_MAP(n, __BPF_DECL_ARGS, __BPF_N, u64, __ur_1, u64, __ur_2,       \
		  u64, __ur_3, u64, __ur_4, u64, __ur_5)

#define BPF_CALL_x(x, name, ...)					       \
	static __always_inline						       \
	u64 ____##name(__BPF_MAP(x, __BPF_DECL_ARGS, __BPF_V, __VA_ARGS__));   \
	u64 name(__BPF_REG(x, __BPF_DECL_REGS, __BPF_N, __VA_ARGS__));	       \
	u64 name(__BPF_REG(x, __BPF_DECL_REGS, __BPF_N, __VA_ARGS__))	       \
	{								       \
		return ____##name(__BPF_MAP(x,__BPF_CAST,__BPF_N,__VA_ARGS__));\
	}								       \
	static __always_inline						       \
	u64 ____##name(__BPF_MAP(x, __BPF_DECL_ARGS, __BPF_V, __VA_ARGS__))

#define BPF_CALL_0(name, ...)	BPF_CALL_x(0, name, __VA_ARGS__)
#define BPF_CALL_1(name, ...)	BPF_CALL_x(1, name, __VA_ARGS__)
#define BPF_CALL_2(name, ...)	BPF_CALL_x(2, name, __VA_ARGS__)
#define BPF_CALL_3(name, ...)	BPF_CALL_x(3, name, __VA_ARGS__)
#define BPF_CALL_4(name, ...)	BPF_CALL_x(4, name, __VA_ARGS__)
#define BPF_CALL_5(name, ...)	BPF_CALL_x(5, name, __VA_ARGS__)

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#define bpf_ctx_range(TYPE, MEMBER)						\
	offsetof(TYPE, MEMBER) ... offsetofend(TYPE, MEMBER) - 1
#define bpf_ctx_range_till(TYPE, MEMBER1, MEMBER2)				\
	offsetof(TYPE, MEMBER1) ... offsetofend(TYPE, MEMBER2) - 1

#define bpf_target_off(TYPE, MEMBER, SIZE, PTR_SIZE)				\
	({									\
		BUILD_BUG_ON(FIELD_SIZEOF(TYPE, MEMBER) != (SIZE));		\
		*(PTR_SIZE) = (SIZE);						\
		offsetof(TYPE, MEMBER);						\
	})

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#ifdef CONFIG_COMPAT
/* A struct sock_filter is architecture independent. */
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struct compat_sock_fprog {
	u16		len;
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	compat_uptr_t	filter;	/* struct sock_filter * */
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};
#endif

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struct sock_fprog_kern {
	u16			len;
	struct sock_filter	*filter;
};

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struct bpf_binary_header {
	unsigned int pages;
	u8 image[];
};

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struct bpf_prog {
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	u16			pages;		/* Number of allocated pages */
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	u16			jited:1,	/* Is our filter JIT'ed? */
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				locked:1,	/* Program image locked? */
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				gpl_compatible:1, /* Is filter GPL compatible? */
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				cb_access:1,	/* Is control block accessed? */
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				dst_needed:1,	/* Do we need dst entry? */
				kprobe_override:1; /* Do we override a kprobe? */
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	enum bpf_prog_type	type;		/* Type of BPF program */
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	u32			len;		/* Number of filter blocks */
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	u32			jited_len;	/* Size of jited insns in bytes */
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	u8			tag[BPF_TAG_SIZE];
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	struct bpf_prog_aux	*aux;		/* Auxiliary fields */
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	struct sock_fprog_kern	*orig_prog;	/* Original BPF program */
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	unsigned int		(*bpf_func)(const void *ctx,
					    const struct bpf_insn *insn);
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	/* Instructions for interpreter */
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	union {
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		struct sock_filter	insns[0];
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		struct bpf_insn		insnsi[0];
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	};
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};

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struct sk_filter {
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	refcount_t	refcnt;
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	struct rcu_head	rcu;
	struct bpf_prog	*prog;
};

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#define BPF_PROG_RUN(filter, ctx)  (*(filter)->bpf_func)(ctx, (filter)->insnsi)
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#define BPF_SKB_CB_LEN QDISC_CB_PRIV_LEN

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struct bpf_skb_data_end {
	struct qdisc_skb_cb qdisc_cb;
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	void *data_meta;
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	void *data_end;
};

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struct xdp_buff {
	void *data;
	void *data_end;
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	void *data_meta;
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	void *data_hard_start;
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};

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/* Compute the linear packet data range [data, data_end) which
 * will be accessed by various program types (cls_bpf, act_bpf,
 * lwt, ...). Subsystems allowing direct data access must (!)
 * ensure that cb[] area can be written to when BPF program is
 * invoked (otherwise cb[] save/restore is necessary).
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 */
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static inline void bpf_compute_data_pointers(struct sk_buff *skb)
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{
	struct bpf_skb_data_end *cb = (struct bpf_skb_data_end *)skb->cb;

	BUILD_BUG_ON(sizeof(*cb) > FIELD_SIZEOF(struct sk_buff, cb));
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	cb->data_meta = skb->data - skb_metadata_len(skb);
	cb->data_end  = skb->data + skb_headlen(skb);
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}

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static inline u8 *bpf_skb_cb(struct sk_buff *skb)
{
	/* eBPF programs may read/write skb->cb[] area to transfer meta
	 * data between tail calls. Since this also needs to work with
	 * tc, that scratch memory is mapped to qdisc_skb_cb's data area.
	 *
	 * In some socket filter cases, the cb unfortunately needs to be
	 * saved/restored so that protocol specific skb->cb[] data won't
	 * be lost. In any case, due to unpriviledged eBPF programs
	 * attached to sockets, we need to clear the bpf_skb_cb() area
	 * to not leak previous contents to user space.
	 */
	BUILD_BUG_ON(FIELD_SIZEOF(struct __sk_buff, cb) != BPF_SKB_CB_LEN);
	BUILD_BUG_ON(FIELD_SIZEOF(struct __sk_buff, cb) !=
		     FIELD_SIZEOF(struct qdisc_skb_cb, data));

	return qdisc_skb_cb(skb)->data;
}

535 536 537
static inline u32 bpf_prog_run_save_cb(const struct bpf_prog *prog,
				       struct sk_buff *skb)
{
538 539
	u8 *cb_data = bpf_skb_cb(skb);
	u8 cb_saved[BPF_SKB_CB_LEN];
540 541 542
	u32 res;

	if (unlikely(prog->cb_access)) {
543 544
		memcpy(cb_saved, cb_data, sizeof(cb_saved));
		memset(cb_data, 0, sizeof(cb_saved));
545 546 547 548 549
	}

	res = BPF_PROG_RUN(prog, skb);

	if (unlikely(prog->cb_access))
550
		memcpy(cb_data, cb_saved, sizeof(cb_saved));
551 552 553 554 555 556 557

	return res;
}

static inline u32 bpf_prog_run_clear_cb(const struct bpf_prog *prog,
					struct sk_buff *skb)
{
558
	u8 *cb_data = bpf_skb_cb(skb);
559 560

	if (unlikely(prog->cb_access))
561 562
		memset(cb_data, 0, BPF_SKB_CB_LEN);

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	return BPF_PROG_RUN(prog, skb);
}

566 567
static __always_inline u32 bpf_prog_run_xdp(const struct bpf_prog *prog,
					    struct xdp_buff *xdp)
568
{
569 570 571 572 573 574 575
	/* Caller needs to hold rcu_read_lock() (!), otherwise program
	 * can be released while still running, or map elements could be
	 * freed early while still having concurrent users. XDP fastpath
	 * already takes rcu_read_lock() when fetching the program, so
	 * it's not necessary here anymore.
	 */
	return BPF_PROG_RUN(prog, xdp);
576 577
}

578 579 580 581 582
static inline u32 bpf_prog_insn_size(const struct bpf_prog *prog)
{
	return prog->len * sizeof(struct bpf_insn);
}

583
static inline u32 bpf_prog_tag_scratch_size(const struct bpf_prog *prog)
584 585 586 587 588
{
	return round_up(bpf_prog_insn_size(prog) +
			sizeof(__be64) + 1, SHA_MESSAGE_BYTES);
}

589
static inline unsigned int bpf_prog_size(unsigned int proglen)
590
{
591 592
	return max(sizeof(struct bpf_prog),
		   offsetof(struct bpf_prog, insns[proglen]));
593 594
}

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static inline bool bpf_prog_was_classic(const struct bpf_prog *prog)
{
	/* When classic BPF programs have been loaded and the arch
	 * does not have a classic BPF JIT (anymore), they have been
	 * converted via bpf_migrate_filter() to eBPF and thus always
	 * have an unspec program type.
	 */
	return prog->type == BPF_PROG_TYPE_UNSPEC;
}

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static inline bool
bpf_ctx_narrow_access_ok(u32 off, u32 size, const u32 size_default)
{
	bool off_ok;
#ifdef __LITTLE_ENDIAN
	off_ok = (off & (size_default - 1)) == 0;
#else
	off_ok = (off & (size_default - 1)) + size == size_default;
#endif
	return off_ok && size <= size_default && (size & (size - 1)) == 0;
}

617
#define bpf_classic_proglen(fprog) (fprog->len * sizeof(fprog->filter[0]))
618

619
#ifdef CONFIG_ARCH_HAS_SET_MEMORY
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static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
{
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	fp->locked = 1;
	WARN_ON_ONCE(set_memory_ro((unsigned long)fp, fp->pages));
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}

static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
{
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	if (fp->locked) {
		WARN_ON_ONCE(set_memory_rw((unsigned long)fp, fp->pages));
		/* In case set_memory_rw() fails, we want to be the first
		 * to crash here instead of some random place later on.
		 */
		fp->locked = 0;
	}
635
}
636

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static inline void bpf_jit_binary_lock_ro(struct bpf_binary_header *hdr)
{
639
	WARN_ON_ONCE(set_memory_ro((unsigned long)hdr, hdr->pages));
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}

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static inline void bpf_jit_binary_unlock_ro(struct bpf_binary_header *hdr)
{
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	WARN_ON_ONCE(set_memory_rw((unsigned long)hdr, hdr->pages));
645
}
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#else
static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
{
}

static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
{
}
654

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static inline void bpf_jit_binary_lock_ro(struct bpf_binary_header *hdr)
{
}

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static inline void bpf_jit_binary_unlock_ro(struct bpf_binary_header *hdr)
{
}
662
#endif /* CONFIG_ARCH_HAS_SET_MEMORY */
663

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static inline struct bpf_binary_header *
bpf_jit_binary_hdr(const struct bpf_prog *fp)
{
	unsigned long real_start = (unsigned long)fp->bpf_func;
	unsigned long addr = real_start & PAGE_MASK;

	return (void *)addr;
}

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int sk_filter_trim_cap(struct sock *sk, struct sk_buff *skb, unsigned int cap);
static inline int sk_filter(struct sock *sk, struct sk_buff *skb)
{
	return sk_filter_trim_cap(sk, skb, 1);
}
678

679
struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err);
680
void bpf_prog_free(struct bpf_prog *fp);
681

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struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags);
struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
				  gfp_t gfp_extra_flags);
void __bpf_prog_free(struct bpf_prog *fp);

static inline void bpf_prog_unlock_free(struct bpf_prog *fp)
{
	bpf_prog_unlock_ro(fp);
	__bpf_prog_free(fp);
}

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typedef int (*bpf_aux_classic_check_t)(struct sock_filter *filter,
				       unsigned int flen);

696
int bpf_prog_create(struct bpf_prog **pfp, struct sock_fprog_kern *fprog);
697
int bpf_prog_create_from_user(struct bpf_prog **pfp, struct sock_fprog *fprog,
698
			      bpf_aux_classic_check_t trans, bool save_orig);
699
void bpf_prog_destroy(struct bpf_prog *fp);
700

701
int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk);
702
int sk_attach_bpf(u32 ufd, struct sock *sk);
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int sk_reuseport_attach_filter(struct sock_fprog *fprog, struct sock *sk);
int sk_reuseport_attach_bpf(u32 ufd, struct sock *sk);
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int sk_detach_filter(struct sock *sk);
int sk_get_filter(struct sock *sk, struct sock_filter __user *filter,
		  unsigned int len);

709
bool sk_filter_charge(struct sock *sk, struct sk_filter *fp);
710
void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp);
711

712
u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
713 714

struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog);
715
void bpf_jit_compile(struct bpf_prog *prog);
716
bool bpf_helper_changes_pkt_data(void *func);
717

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struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,
				       const struct bpf_insn *patch, u32 len);
720

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/* The pair of xdp_do_redirect and xdp_do_flush_map MUST be called in the
 * same cpu context. Further for best results no more than a single map
 * for the do_redirect/do_flush pair should be used. This limitation is
 * because we only track one map and force a flush when the map changes.
725
 * This does not appear to be a real limitation for existing software.
726
 */
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int xdp_do_generic_redirect(struct net_device *dev, struct sk_buff *skb,
			    struct bpf_prog *prog);
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int xdp_do_redirect(struct net_device *dev,
		    struct xdp_buff *xdp,
		    struct bpf_prog *prog);
732
void xdp_do_flush_map(void);
733

734 735 736 737 738 739 740 741 742 743 744 745 746 747 748
/* Drivers not supporting XDP metadata can use this helper, which
 * rejects any room expansion for metadata as a result.
 */
static __always_inline void
xdp_set_data_meta_invalid(struct xdp_buff *xdp)
{
	xdp->data_meta = xdp->data + 1;
}

static __always_inline bool
xdp_data_meta_unsupported(const struct xdp_buff *xdp)
{
	return unlikely(xdp->data_meta > xdp->data);
}

749
void bpf_warn_invalid_xdp_action(u32 act);
750

751
struct sock *do_sk_redirect_map(struct sk_buff *skb);
752

753
#ifdef CONFIG_BPF_JIT
754
extern int bpf_jit_enable;
755
extern int bpf_jit_harden;
756
extern int bpf_jit_kallsyms;
757

758 759 760 761 762 763 764 765 766 767
typedef void (*bpf_jit_fill_hole_t)(void *area, unsigned int size);

struct bpf_binary_header *
bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
		     unsigned int alignment,
		     bpf_jit_fill_hole_t bpf_fill_ill_insns);
void bpf_jit_binary_free(struct bpf_binary_header *hdr);

void bpf_jit_free(struct bpf_prog *fp);

768 769 770
struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *fp);
void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other);

771 772 773
static inline void bpf_jit_dump(unsigned int flen, unsigned int proglen,
				u32 pass, void *image)
{
774 775 776
	pr_err("flen=%u proglen=%u pass=%u image=%pK from=%s pid=%d\n", flen,
	       proglen, pass, image, current->comm, task_pid_nr(current));

777 778 779 780
	if (image)
		print_hex_dump(KERN_ERR, "JIT code: ", DUMP_PREFIX_OFFSET,
			       16, 1, image, proglen, false);
}
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static inline bool bpf_jit_is_ebpf(void)
{
# ifdef CONFIG_HAVE_EBPF_JIT
	return true;
# else
	return false;
# endif
}

791 792 793 794 795
static inline bool ebpf_jit_enabled(void)
{
	return bpf_jit_enable && bpf_jit_is_ebpf();
}

796 797 798 799 800
static inline bool bpf_prog_ebpf_jited(const struct bpf_prog *fp)
{
	return fp->jited && bpf_jit_is_ebpf();
}

801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817
static inline bool bpf_jit_blinding_enabled(void)
{
	/* These are the prerequisites, should someone ever have the
	 * idea to call blinding outside of them, we make sure to
	 * bail out.
	 */
	if (!bpf_jit_is_ebpf())
		return false;
	if (!bpf_jit_enable)
		return false;
	if (!bpf_jit_harden)
		return false;
	if (bpf_jit_harden == 1 && capable(CAP_SYS_ADMIN))
		return false;

	return true;
}
818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855

static inline bool bpf_jit_kallsyms_enabled(void)
{
	/* There are a couple of corner cases where kallsyms should
	 * not be enabled f.e. on hardening.
	 */
	if (bpf_jit_harden)
		return false;
	if (!bpf_jit_kallsyms)
		return false;
	if (bpf_jit_kallsyms == 1)
		return true;

	return false;
}

const char *__bpf_address_lookup(unsigned long addr, unsigned long *size,
				 unsigned long *off, char *sym);
bool is_bpf_text_address(unsigned long addr);
int bpf_get_kallsym(unsigned int symnum, unsigned long *value, char *type,
		    char *sym);

static inline const char *
bpf_address_lookup(unsigned long addr, unsigned long *size,
		   unsigned long *off, char **modname, char *sym)
{
	const char *ret = __bpf_address_lookup(addr, size, off, sym);

	if (ret && modname)
		*modname = NULL;
	return ret;
}

void bpf_prog_kallsyms_add(struct bpf_prog *fp);
void bpf_prog_kallsyms_del(struct bpf_prog *fp);

#else /* CONFIG_BPF_JIT */

856 857 858 859 860
static inline bool ebpf_jit_enabled(void)
{
	return false;
}

861 862 863 864 865
static inline bool bpf_prog_ebpf_jited(const struct bpf_prog *fp)
{
	return false;
}

866 867 868 869
static inline void bpf_jit_free(struct bpf_prog *fp)
{
	bpf_prog_unlock_free(fp);
}
870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907

static inline bool bpf_jit_kallsyms_enabled(void)
{
	return false;
}

static inline const char *
__bpf_address_lookup(unsigned long addr, unsigned long *size,
		     unsigned long *off, char *sym)
{
	return NULL;
}

static inline bool is_bpf_text_address(unsigned long addr)
{
	return false;
}

static inline int bpf_get_kallsym(unsigned int symnum, unsigned long *value,
				  char *type, char *sym)
{
	return -ERANGE;
}

static inline const char *
bpf_address_lookup(unsigned long addr, unsigned long *size,
		   unsigned long *off, char **modname, char *sym)
{
	return NULL;
}

static inline void bpf_prog_kallsyms_add(struct bpf_prog *fp)
{
}

static inline void bpf_prog_kallsyms_del(struct bpf_prog *fp)
{
}
908 909
#endif /* CONFIG_BPF_JIT */

910 911
#define BPF_ANC		BIT(15)

912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930
static inline bool bpf_needs_clear_a(const struct sock_filter *first)
{
	switch (first->code) {
	case BPF_RET | BPF_K:
	case BPF_LD | BPF_W | BPF_LEN:
		return false;

	case BPF_LD | BPF_W | BPF_ABS:
	case BPF_LD | BPF_H | BPF_ABS:
	case BPF_LD | BPF_B | BPF_ABS:
		if (first->k == SKF_AD_OFF + SKF_AD_ALU_XOR_X)
			return true;
		return false;

	default:
		return true;
	}
}

931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956
static inline u16 bpf_anc_helper(const struct sock_filter *ftest)
{
	BUG_ON(ftest->code & BPF_ANC);

	switch (ftest->code) {
	case BPF_LD | BPF_W | BPF_ABS:
	case BPF_LD | BPF_H | BPF_ABS:
	case BPF_LD | BPF_B | BPF_ABS:
#define BPF_ANCILLARY(CODE)	case SKF_AD_OFF + SKF_AD_##CODE:	\
				return BPF_ANC | SKF_AD_##CODE
		switch (ftest->k) {
		BPF_ANCILLARY(PROTOCOL);
		BPF_ANCILLARY(PKTTYPE);
		BPF_ANCILLARY(IFINDEX);
		BPF_ANCILLARY(NLATTR);
		BPF_ANCILLARY(NLATTR_NEST);
		BPF_ANCILLARY(MARK);
		BPF_ANCILLARY(QUEUE);
		BPF_ANCILLARY(HATYPE);
		BPF_ANCILLARY(RXHASH);
		BPF_ANCILLARY(CPU);
		BPF_ANCILLARY(ALU_XOR_X);
		BPF_ANCILLARY(VLAN_TAG);
		BPF_ANCILLARY(VLAN_TAG_PRESENT);
		BPF_ANCILLARY(PAY_OFFSET);
		BPF_ANCILLARY(RANDOM);
957
		BPF_ANCILLARY(VLAN_TPID);
958 959 960 961 962 963 964
		}
		/* Fallthrough. */
	default:
		return ftest->code;
	}
}

965 966 967 968 969 970 971 972 973 974 975 976
void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb,
					   int k, unsigned int size);

static inline void *bpf_load_pointer(const struct sk_buff *skb, int k,
				     unsigned int size, void *buffer)
{
	if (k >= 0)
		return skb_header_pointer(skb, k, size, buffer);

	return bpf_internal_load_pointer_neg_helper(skb, k, size);
}

977 978
static inline int bpf_tell_extensions(void)
{
979
	return SKF_AD_MAX;
980 981
}

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Lawrence Brakmo 已提交
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struct bpf_sock_ops_kern {
	struct	sock *sk;
	u32	op;
	union {
		u32 reply;
		u32 replylong[4];
	};
989
	u32	is_fullsock;
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Lawrence Brakmo 已提交
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};

L
Linus Torvalds 已提交
992
#endif /* __LINUX_FILTER_H__ */