481 lines
12 KiB
C
481 lines
12 KiB
C
/*
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* Linux Socket Filter Data Structures
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*/
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#ifndef __LINUX_FILTER_H__
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#define __LINUX_FILTER_H__
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#include <stdarg.h>
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#include <linux/atomic.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>
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#include <linux/printk.h>
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#include <linux/workqueue.h>
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#include <asm/cacheflush.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;
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struct sock;
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struct seccomp_data;
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struct bpf_prog_aux;
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/* ArgX, context and stack frame pointer register positions. Note,
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* Arg1, Arg2, Arg3, etc are used as argument mappings of function
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* calls in BPF_CALL instruction.
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*/
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#define BPF_REG_ARG1 BPF_REG_1
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#define BPF_REG_ARG2 BPF_REG_2
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#define BPF_REG_ARG3 BPF_REG_3
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#define BPF_REG_ARG4 BPF_REG_4
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#define BPF_REG_ARG5 BPF_REG_5
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#define BPF_REG_CTX BPF_REG_6
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#define BPF_REG_FP BPF_REG_10
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/* Additional register mappings for converted user programs. */
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#define BPF_REG_A BPF_REG_0
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#define BPF_REG_X BPF_REG_7
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#define BPF_REG_TMP BPF_REG_8
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/* BPF program can access up to 512 bytes of stack space. */
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#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, \
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.src_reg = SRC, \
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.off = 0, \
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.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, \
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.src_reg = SRC, \
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.off = 0, \
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.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, \
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.src_reg = 0, \
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.off = 0, \
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.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, \
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.src_reg = 0, \
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.off = 0, \
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.imm = IMM })
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/* 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, \
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.src_reg = 0, \
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.off = 0, \
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.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, \
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.src_reg = SRC, \
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.off = 0, \
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.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, \
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.src_reg = SRC, \
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.off = 0, \
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.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, \
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.src_reg = 0, \
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.off = 0, \
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.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, \
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.src_reg = 0, \
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.off = 0, \
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.imm = IMM })
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/* BPF_LD_IMM64 macro encodes single 'load 64-bit immediate' insn */
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#define BPF_LD_IMM64(DST, IMM) \
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BPF_LD_IMM64_RAW(DST, 0, IMM)
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#define BPF_LD_IMM64_RAW(DST, SRC, IMM) \
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((struct bpf_insn) { \
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.code = BPF_LD | BPF_DW | BPF_IMM, \
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.dst_reg = DST, \
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.src_reg = SRC, \
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.off = 0, \
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.imm = (__u32) (IMM) }), \
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((struct bpf_insn) { \
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.code = 0, /* zero is reserved opcode */ \
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.dst_reg = 0, \
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.src_reg = 0, \
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.off = 0, \
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.imm = ((__u64) (IMM)) >> 32 })
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#define BPF_PSEUDO_MAP_FD 1
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/* pseudo BPF_LD_IMM64 insn used to refer to process-local map_fd */
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#define BPF_LD_MAP_FD(DST, MAP_FD) \
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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, \
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.src_reg = SRC, \
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.off = 0, \
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.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, \
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.src_reg = SRC, \
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.off = 0, \
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.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, \
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.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, \
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.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, \
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.src_reg = SRC, \
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.off = OFF, \
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.imm = 0 })
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/* Memory store, *(uint *) (dst_reg + off16) = src_reg */
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#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, \
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.src_reg = SRC, \
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.off = OFF, \
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.imm = 0 })
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/* Memory store, *(uint *) (dst_reg + off16) = imm32 */
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#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, \
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.dst_reg = DST, \
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.src_reg = 0, \
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.off = OFF, \
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.imm = IMM })
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/* 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, \
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.src_reg = SRC, \
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.off = OFF, \
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.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, \
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.src_reg = 0, \
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.off = OFF, \
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.imm = IMM })
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/* Function call */
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#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, \
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.src_reg = 0, \
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.off = 0, \
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.imm = ((FUNC) - __bpf_call_base) })
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/* 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, \
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.src_reg = SRC, \
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.off = OFF, \
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.imm = IMM })
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/* Program exit */
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#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, \
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.src_reg = 0, \
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.off = 0, \
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.imm = 0 })
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#define bytes_to_bpf_size(bytes) \
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({ \
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int bpf_size = -EINVAL; \
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\
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if (bytes == sizeof(u8)) \
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bpf_size = BPF_B; \
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else if (bytes == sizeof(u16)) \
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bpf_size = BPF_H; \
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else if (bytes == sizeof(u32)) \
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bpf_size = BPF_W; \
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else if (bytes == sizeof(u64)) \
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bpf_size = BPF_DW; \
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\
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bpf_size; \
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})
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/* Macro to invoke filter function. */
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#define SK_RUN_FILTER(filter, ctx) \
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(*filter->prog->bpf_func)(ctx, filter->prog->insnsi)
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#ifdef CONFIG_COMPAT
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/* A struct sock_filter is architecture independent. */
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struct compat_sock_fprog {
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u16 len;
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compat_uptr_t filter; /* struct sock_filter * */
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};
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#endif
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struct sock_fprog_kern {
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u16 len;
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struct sock_filter *filter;
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};
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struct bpf_binary_header {
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unsigned int pages;
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u8 image[];
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};
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struct bpf_prog {
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u16 pages; /* Number of allocated pages */
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bool jited; /* Is our filter JIT'ed? */
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u32 len; /* Number of filter blocks */
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struct sock_fprog_kern *orig_prog; /* Original BPF program */
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struct bpf_prog_aux *aux; /* Auxiliary fields */
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unsigned int (*bpf_func)(const struct sk_buff *skb,
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const struct bpf_insn *filter);
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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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atomic_t refcnt;
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struct rcu_head rcu;
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struct bpf_prog *prog;
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};
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#define BPF_PROG_RUN(filter, ctx) (*filter->bpf_func)(ctx, filter->insnsi)
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static inline unsigned int bpf_prog_size(unsigned int proglen)
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{
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return max(sizeof(struct bpf_prog),
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offsetof(struct bpf_prog, insns[proglen]));
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}
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#define bpf_classic_proglen(fprog) (fprog->len * sizeof(fprog->filter[0]))
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#ifdef CONFIG_DEBUG_SET_MODULE_RONX
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static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
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{
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set_memory_ro((unsigned long)fp, fp->pages);
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}
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static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
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{
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set_memory_rw((unsigned long)fp, fp->pages);
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}
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#else
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static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
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{
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}
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static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
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{
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}
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#endif /* CONFIG_DEBUG_SET_MODULE_RONX */
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int sk_filter(struct sock *sk, struct sk_buff *skb);
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void bpf_prog_select_runtime(struct bpf_prog *fp);
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void bpf_prog_free(struct bpf_prog *fp);
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int bpf_convert_filter(struct sock_filter *prog, int len,
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struct bpf_insn *new_prog, int *new_len);
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struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags);
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struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
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gfp_t gfp_extra_flags);
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void __bpf_prog_free(struct bpf_prog *fp);
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static inline void bpf_prog_unlock_free(struct bpf_prog *fp)
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{
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bpf_prog_unlock_ro(fp);
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__bpf_prog_free(fp);
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}
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int bpf_prog_create(struct bpf_prog **pfp, struct sock_fprog_kern *fprog);
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void bpf_prog_destroy(struct bpf_prog *fp);
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int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk);
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int sk_detach_filter(struct sock *sk);
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int bpf_check_classic(const struct sock_filter *filter, unsigned int flen);
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int sk_get_filter(struct sock *sk, struct sock_filter __user *filter,
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unsigned int len);
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bool sk_filter_charge(struct sock *sk, struct sk_filter *fp);
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void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp);
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u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
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void bpf_int_jit_compile(struct bpf_prog *fp);
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#ifdef CONFIG_BPF_JIT
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typedef void (*bpf_jit_fill_hole_t)(void *area, unsigned int size);
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struct bpf_binary_header *
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bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
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unsigned int alignment,
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bpf_jit_fill_hole_t bpf_fill_ill_insns);
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void bpf_jit_binary_free(struct bpf_binary_header *hdr);
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void bpf_jit_compile(struct bpf_prog *fp);
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void bpf_jit_free(struct bpf_prog *fp);
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static inline void bpf_jit_dump(unsigned int flen, unsigned int proglen,
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u32 pass, void *image)
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{
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pr_err("flen=%u proglen=%u pass=%u image=%pK\n",
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flen, proglen, pass, image);
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if (image)
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print_hex_dump(KERN_ERR, "JIT code: ", DUMP_PREFIX_OFFSET,
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16, 1, image, proglen, false);
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}
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#else
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static inline void bpf_jit_compile(struct bpf_prog *fp)
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{
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}
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static inline void bpf_jit_free(struct bpf_prog *fp)
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{
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bpf_prog_unlock_free(fp);
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}
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#endif /* CONFIG_BPF_JIT */
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#define BPF_ANC BIT(15)
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static inline u16 bpf_anc_helper(const struct sock_filter *ftest)
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{
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BUG_ON(ftest->code & BPF_ANC);
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switch (ftest->code) {
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case BPF_LD | BPF_W | BPF_ABS:
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case BPF_LD | BPF_H | BPF_ABS:
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case BPF_LD | BPF_B | BPF_ABS:
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#define BPF_ANCILLARY(CODE) case SKF_AD_OFF + SKF_AD_##CODE: \
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return BPF_ANC | SKF_AD_##CODE
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switch (ftest->k) {
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BPF_ANCILLARY(PROTOCOL);
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BPF_ANCILLARY(PKTTYPE);
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BPF_ANCILLARY(IFINDEX);
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BPF_ANCILLARY(NLATTR);
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BPF_ANCILLARY(NLATTR_NEST);
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BPF_ANCILLARY(MARK);
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BPF_ANCILLARY(QUEUE);
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BPF_ANCILLARY(HATYPE);
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BPF_ANCILLARY(RXHASH);
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BPF_ANCILLARY(CPU);
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BPF_ANCILLARY(ALU_XOR_X);
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BPF_ANCILLARY(VLAN_TAG);
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BPF_ANCILLARY(VLAN_TAG_PRESENT);
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BPF_ANCILLARY(PAY_OFFSET);
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BPF_ANCILLARY(RANDOM);
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}
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/* Fallthrough. */
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default:
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return ftest->code;
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}
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}
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void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb,
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int k, unsigned int size);
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static inline void *bpf_load_pointer(const struct sk_buff *skb, int k,
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unsigned int size, void *buffer)
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{
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if (k >= 0)
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return skb_header_pointer(skb, k, size, buffer);
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return bpf_internal_load_pointer_neg_helper(skb, k, size);
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}
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static inline int bpf_tell_extensions(void)
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{
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return SKF_AD_MAX;
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}
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#endif /* __LINUX_FILTER_H__ */
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