2 * Linux Socket Filter Data Structures
4 #ifndef __LINUX_FILTER_H__
5 #define __LINUX_FILTER_H__
9 #include <linux/atomic.h>
10 #include <linux/compat.h>
11 #include <linux/skbuff.h>
12 #include <linux/linkage.h>
13 #include <linux/printk.h>
14 #include <linux/workqueue.h>
15 #include <linux/sched.h>
16 #include <linux/capability.h>
17 #include <linux/cryptohash.h>
19 #include <net/sch_generic.h>
21 #include <asm/cacheflush.h>
23 #include <uapi/linux/filter.h>
24 #include <uapi/linux/bpf.h>
31 /* ArgX, context and stack frame pointer register positions. Note,
32 * Arg1, Arg2, Arg3, etc are used as argument mappings of function
33 * calls in BPF_CALL instruction.
35 #define BPF_REG_ARG1 BPF_REG_1
36 #define BPF_REG_ARG2 BPF_REG_2
37 #define BPF_REG_ARG3 BPF_REG_3
38 #define BPF_REG_ARG4 BPF_REG_4
39 #define BPF_REG_ARG5 BPF_REG_5
40 #define BPF_REG_CTX BPF_REG_6
41 #define BPF_REG_FP BPF_REG_10
43 /* Additional register mappings for converted user programs. */
44 #define BPF_REG_A BPF_REG_0
45 #define BPF_REG_X BPF_REG_7
46 #define BPF_REG_TMP BPF_REG_8
48 /* Kernel hidden auxiliary/helper register for hardening step.
49 * Only used by eBPF JITs. It's nothing more than a temporary
50 * register that JITs use internally, only that here it's part
51 * of eBPF instructions that have been rewritten for blinding
52 * constants. See JIT pre-step in bpf_jit_blind_constants().
54 #define BPF_REG_AX MAX_BPF_REG
55 #define MAX_BPF_JIT_REG (MAX_BPF_REG + 1)
57 /* BPF program can access up to 512 bytes of stack space. */
58 #define MAX_BPF_STACK 512
60 #define BPF_TAG_SIZE 8
62 /* Helper macros for filter block array initializers. */
64 /* ALU ops on registers, bpf_add|sub|...: dst_reg += src_reg */
66 #define BPF_ALU64_REG(OP, DST, SRC) \
67 ((struct bpf_insn) { \
68 .code = BPF_ALU64 | BPF_OP(OP) | BPF_X, \
74 #define BPF_ALU32_REG(OP, DST, SRC) \
75 ((struct bpf_insn) { \
76 .code = BPF_ALU | BPF_OP(OP) | BPF_X, \
82 /* ALU ops on immediates, bpf_add|sub|...: dst_reg += imm32 */
84 #define BPF_ALU64_IMM(OP, DST, IMM) \
85 ((struct bpf_insn) { \
86 .code = BPF_ALU64 | BPF_OP(OP) | BPF_K, \
92 #define BPF_ALU32_IMM(OP, DST, IMM) \
93 ((struct bpf_insn) { \
94 .code = BPF_ALU | BPF_OP(OP) | BPF_K, \
100 /* Endianess conversion, cpu_to_{l,b}e(), {l,b}e_to_cpu() */
102 #define BPF_ENDIAN(TYPE, DST, LEN) \
103 ((struct bpf_insn) { \
104 .code = BPF_ALU | BPF_END | BPF_SRC(TYPE), \
110 /* Short form of mov, dst_reg = src_reg */
112 #define BPF_MOV64_REG(DST, SRC) \
113 ((struct bpf_insn) { \
114 .code = BPF_ALU64 | BPF_MOV | BPF_X, \
120 #define BPF_MOV32_REG(DST, SRC) \
121 ((struct bpf_insn) { \
122 .code = BPF_ALU | BPF_MOV | BPF_X, \
128 /* Short form of mov, dst_reg = imm32 */
130 #define BPF_MOV64_IMM(DST, IMM) \
131 ((struct bpf_insn) { \
132 .code = BPF_ALU64 | BPF_MOV | BPF_K, \
138 #define BPF_MOV32_IMM(DST, IMM) \
139 ((struct bpf_insn) { \
140 .code = BPF_ALU | BPF_MOV | BPF_K, \
146 /* BPF_LD_IMM64 macro encodes single 'load 64-bit immediate' insn */
147 #define BPF_LD_IMM64(DST, IMM) \
148 BPF_LD_IMM64_RAW(DST, 0, IMM)
150 #define BPF_LD_IMM64_RAW(DST, SRC, IMM) \
151 ((struct bpf_insn) { \
152 .code = BPF_LD | BPF_DW | BPF_IMM, \
156 .imm = (__u32) (IMM) }), \
157 ((struct bpf_insn) { \
158 .code = 0, /* zero is reserved opcode */ \
162 .imm = ((__u64) (IMM)) >> 32 })
164 /* pseudo BPF_LD_IMM64 insn used to refer to process-local map_fd */
165 #define BPF_LD_MAP_FD(DST, MAP_FD) \
166 BPF_LD_IMM64_RAW(DST, BPF_PSEUDO_MAP_FD, MAP_FD)
168 /* Short form of mov based on type, BPF_X: dst_reg = src_reg, BPF_K: dst_reg = imm32 */
170 #define BPF_MOV64_RAW(TYPE, DST, SRC, IMM) \
171 ((struct bpf_insn) { \
172 .code = BPF_ALU64 | BPF_MOV | BPF_SRC(TYPE), \
178 #define BPF_MOV32_RAW(TYPE, DST, SRC, IMM) \
179 ((struct bpf_insn) { \
180 .code = BPF_ALU | BPF_MOV | BPF_SRC(TYPE), \
186 /* Direct packet access, R0 = *(uint *) (skb->data + imm32) */
188 #define BPF_LD_ABS(SIZE, IMM) \
189 ((struct bpf_insn) { \
190 .code = BPF_LD | BPF_SIZE(SIZE) | BPF_ABS, \
196 /* Indirect packet access, R0 = *(uint *) (skb->data + src_reg + imm32) */
198 #define BPF_LD_IND(SIZE, SRC, IMM) \
199 ((struct bpf_insn) { \
200 .code = BPF_LD | BPF_SIZE(SIZE) | BPF_IND, \
206 /* Memory load, dst_reg = *(uint *) (src_reg + off16) */
208 #define BPF_LDX_MEM(SIZE, DST, SRC, OFF) \
209 ((struct bpf_insn) { \
210 .code = BPF_LDX | BPF_SIZE(SIZE) | BPF_MEM, \
216 /* Memory store, *(uint *) (dst_reg + off16) = src_reg */
218 #define BPF_STX_MEM(SIZE, DST, SRC, OFF) \
219 ((struct bpf_insn) { \
220 .code = BPF_STX | BPF_SIZE(SIZE) | BPF_MEM, \
226 /* Atomic memory add, *(uint *)(dst_reg + off16) += src_reg */
228 #define BPF_STX_XADD(SIZE, DST, SRC, OFF) \
229 ((struct bpf_insn) { \
230 .code = BPF_STX | BPF_SIZE(SIZE) | BPF_XADD, \
236 /* Memory store, *(uint *) (dst_reg + off16) = imm32 */
238 #define BPF_ST_MEM(SIZE, DST, OFF, IMM) \
239 ((struct bpf_insn) { \
240 .code = BPF_ST | BPF_SIZE(SIZE) | BPF_MEM, \
246 /* Conditional jumps against registers, if (dst_reg 'op' src_reg) goto pc + off16 */
248 #define BPF_JMP_REG(OP, DST, SRC, OFF) \
249 ((struct bpf_insn) { \
250 .code = BPF_JMP | BPF_OP(OP) | BPF_X, \
256 /* Conditional jumps against immediates, if (dst_reg 'op' imm32) goto pc + off16 */
258 #define BPF_JMP_IMM(OP, DST, IMM, OFF) \
259 ((struct bpf_insn) { \
260 .code = BPF_JMP | BPF_OP(OP) | BPF_K, \
268 #define BPF_EMIT_CALL(FUNC) \
269 ((struct bpf_insn) { \
270 .code = BPF_JMP | BPF_CALL, \
274 .imm = ((FUNC) - __bpf_call_base) })
276 /* Raw code statement block */
278 #define BPF_RAW_INSN(CODE, DST, SRC, OFF, IMM) \
279 ((struct bpf_insn) { \
288 #define BPF_EXIT_INSN() \
289 ((struct bpf_insn) { \
290 .code = BPF_JMP | BPF_EXIT, \
296 /* Internal classic blocks for direct assignment */
298 #define __BPF_STMT(CODE, K) \
299 ((struct sock_filter) BPF_STMT(CODE, K))
301 #define __BPF_JUMP(CODE, K, JT, JF) \
302 ((struct sock_filter) BPF_JUMP(CODE, K, JT, JF))
304 #define bytes_to_bpf_size(bytes) \
306 int bpf_size = -EINVAL; \
308 if (bytes == sizeof(u8)) \
310 else if (bytes == sizeof(u16)) \
312 else if (bytes == sizeof(u32)) \
314 else if (bytes == sizeof(u64)) \
320 #define BPF_SIZEOF(type) \
322 const int __size = bytes_to_bpf_size(sizeof(type)); \
323 BUILD_BUG_ON(__size < 0); \
327 #define BPF_FIELD_SIZEOF(type, field) \
329 const int __size = bytes_to_bpf_size(FIELD_SIZEOF(type, field)); \
330 BUILD_BUG_ON(__size < 0); \
334 #define __BPF_MAP_0(m, v, ...) v
335 #define __BPF_MAP_1(m, v, t, a, ...) m(t, a)
336 #define __BPF_MAP_2(m, v, t, a, ...) m(t, a), __BPF_MAP_1(m, v, __VA_ARGS__)
337 #define __BPF_MAP_3(m, v, t, a, ...) m(t, a), __BPF_MAP_2(m, v, __VA_ARGS__)
338 #define __BPF_MAP_4(m, v, t, a, ...) m(t, a), __BPF_MAP_3(m, v, __VA_ARGS__)
339 #define __BPF_MAP_5(m, v, t, a, ...) m(t, a), __BPF_MAP_4(m, v, __VA_ARGS__)
341 #define __BPF_REG_0(...) __BPF_PAD(5)
342 #define __BPF_REG_1(...) __BPF_MAP(1, __VA_ARGS__), __BPF_PAD(4)
343 #define __BPF_REG_2(...) __BPF_MAP(2, __VA_ARGS__), __BPF_PAD(3)
344 #define __BPF_REG_3(...) __BPF_MAP(3, __VA_ARGS__), __BPF_PAD(2)
345 #define __BPF_REG_4(...) __BPF_MAP(4, __VA_ARGS__), __BPF_PAD(1)
346 #define __BPF_REG_5(...) __BPF_MAP(5, __VA_ARGS__)
348 #define __BPF_MAP(n, ...) __BPF_MAP_##n(__VA_ARGS__)
349 #define __BPF_REG(n, ...) __BPF_REG_##n(__VA_ARGS__)
351 #define __BPF_CAST(t, a) \
354 typeof(__builtin_choose_expr(sizeof(t) == sizeof(unsigned long), \
355 (unsigned long)0, (t)0))) a
359 #define __BPF_DECL_ARGS(t, a) t a
360 #define __BPF_DECL_REGS(t, a) u64 a
362 #define __BPF_PAD(n) \
363 __BPF_MAP(n, __BPF_DECL_ARGS, __BPF_N, u64, __ur_1, u64, __ur_2, \
364 u64, __ur_3, u64, __ur_4, u64, __ur_5)
366 #define BPF_CALL_x(x, name, ...) \
367 static __always_inline \
368 u64 ____##name(__BPF_MAP(x, __BPF_DECL_ARGS, __BPF_V, __VA_ARGS__)); \
369 u64 name(__BPF_REG(x, __BPF_DECL_REGS, __BPF_N, __VA_ARGS__)); \
370 u64 name(__BPF_REG(x, __BPF_DECL_REGS, __BPF_N, __VA_ARGS__)) \
372 return ____##name(__BPF_MAP(x,__BPF_CAST,__BPF_N,__VA_ARGS__));\
374 static __always_inline \
375 u64 ____##name(__BPF_MAP(x, __BPF_DECL_ARGS, __BPF_V, __VA_ARGS__))
377 #define BPF_CALL_0(name, ...) BPF_CALL_x(0, name, __VA_ARGS__)
378 #define BPF_CALL_1(name, ...) BPF_CALL_x(1, name, __VA_ARGS__)
379 #define BPF_CALL_2(name, ...) BPF_CALL_x(2, name, __VA_ARGS__)
380 #define BPF_CALL_3(name, ...) BPF_CALL_x(3, name, __VA_ARGS__)
381 #define BPF_CALL_4(name, ...) BPF_CALL_x(4, name, __VA_ARGS__)
382 #define BPF_CALL_5(name, ...) BPF_CALL_x(5, name, __VA_ARGS__)
385 /* A struct sock_filter is architecture independent. */
386 struct compat_sock_fprog {
388 compat_uptr_t filter; /* struct sock_filter * */
392 struct sock_fprog_kern {
394 struct sock_filter *filter;
397 struct bpf_binary_header {
403 u16 pages; /* Number of allocated pages */
404 kmemcheck_bitfield_begin(meta);
405 u16 jited:1, /* Is our filter JIT'ed? */
406 gpl_compatible:1, /* Is filter GPL compatible? */
407 cb_access:1, /* Is control block accessed? */
408 dst_needed:1, /* Do we need dst entry? */
409 xdp_adjust_head:1; /* Adjusting pkt head? */
410 kmemcheck_bitfield_end(meta);
411 enum bpf_prog_type type; /* Type of BPF program */
412 u32 len; /* Number of filter blocks */
413 u8 tag[BPF_TAG_SIZE];
414 struct bpf_prog_aux *aux; /* Auxiliary fields */
415 struct sock_fprog_kern *orig_prog; /* Original BPF program */
416 unsigned int (*bpf_func)(const void *ctx,
417 const struct bpf_insn *insn);
418 /* Instructions for interpreter */
420 struct sock_filter insns[0];
421 struct bpf_insn insnsi[0];
428 struct bpf_prog *prog;
431 #define BPF_PROG_RUN(filter, ctx) (*filter->bpf_func)(ctx, filter->insnsi)
433 #define BPF_SKB_CB_LEN QDISC_CB_PRIV_LEN
435 struct bpf_skb_data_end {
436 struct qdisc_skb_cb qdisc_cb;
443 void *data_hard_start;
446 /* compute the linear packet data range [data, data_end) which
447 * will be accessed by cls_bpf, act_bpf and lwt programs
449 static inline void bpf_compute_data_end(struct sk_buff *skb)
451 struct bpf_skb_data_end *cb = (struct bpf_skb_data_end *)skb->cb;
453 BUILD_BUG_ON(sizeof(*cb) > FIELD_SIZEOF(struct sk_buff, cb));
454 cb->data_end = skb->data + skb_headlen(skb);
457 static inline u8 *bpf_skb_cb(struct sk_buff *skb)
459 /* eBPF programs may read/write skb->cb[] area to transfer meta
460 * data between tail calls. Since this also needs to work with
461 * tc, that scratch memory is mapped to qdisc_skb_cb's data area.
463 * In some socket filter cases, the cb unfortunately needs to be
464 * saved/restored so that protocol specific skb->cb[] data won't
465 * be lost. In any case, due to unpriviledged eBPF programs
466 * attached to sockets, we need to clear the bpf_skb_cb() area
467 * to not leak previous contents to user space.
469 BUILD_BUG_ON(FIELD_SIZEOF(struct __sk_buff, cb) != BPF_SKB_CB_LEN);
470 BUILD_BUG_ON(FIELD_SIZEOF(struct __sk_buff, cb) !=
471 FIELD_SIZEOF(struct qdisc_skb_cb, data));
473 return qdisc_skb_cb(skb)->data;
476 static inline u32 bpf_prog_run_save_cb(const struct bpf_prog *prog,
479 u8 *cb_data = bpf_skb_cb(skb);
480 u8 cb_saved[BPF_SKB_CB_LEN];
483 if (unlikely(prog->cb_access)) {
484 memcpy(cb_saved, cb_data, sizeof(cb_saved));
485 memset(cb_data, 0, sizeof(cb_saved));
488 res = BPF_PROG_RUN(prog, skb);
490 if (unlikely(prog->cb_access))
491 memcpy(cb_data, cb_saved, sizeof(cb_saved));
496 static inline u32 bpf_prog_run_clear_cb(const struct bpf_prog *prog,
499 u8 *cb_data = bpf_skb_cb(skb);
501 if (unlikely(prog->cb_access))
502 memset(cb_data, 0, BPF_SKB_CB_LEN);
504 return BPF_PROG_RUN(prog, skb);
507 static __always_inline u32 bpf_prog_run_xdp(const struct bpf_prog *prog,
508 struct xdp_buff *xdp)
510 /* Caller needs to hold rcu_read_lock() (!), otherwise program
511 * can be released while still running, or map elements could be
512 * freed early while still having concurrent users. XDP fastpath
513 * already takes rcu_read_lock() when fetching the program, so
514 * it's not necessary here anymore.
516 return BPF_PROG_RUN(prog, xdp);
519 static inline u32 bpf_prog_insn_size(const struct bpf_prog *prog)
521 return prog->len * sizeof(struct bpf_insn);
524 static inline u32 bpf_prog_tag_scratch_size(const struct bpf_prog *prog)
526 return round_up(bpf_prog_insn_size(prog) +
527 sizeof(__be64) + 1, SHA_MESSAGE_BYTES);
530 static inline unsigned int bpf_prog_size(unsigned int proglen)
532 return max(sizeof(struct bpf_prog),
533 offsetof(struct bpf_prog, insns[proglen]));
536 static inline bool bpf_prog_was_classic(const struct bpf_prog *prog)
538 /* When classic BPF programs have been loaded and the arch
539 * does not have a classic BPF JIT (anymore), they have been
540 * converted via bpf_migrate_filter() to eBPF and thus always
541 * have an unspec program type.
543 return prog->type == BPF_PROG_TYPE_UNSPEC;
546 #define bpf_classic_proglen(fprog) (fprog->len * sizeof(fprog->filter[0]))
548 #ifdef CONFIG_STRICT_MODULE_RWX
549 static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
551 set_memory_ro((unsigned long)fp, fp->pages);
554 static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
556 set_memory_rw((unsigned long)fp, fp->pages);
559 static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
563 static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
566 #endif /* CONFIG_STRICT_MODULE_RWX */
568 int sk_filter_trim_cap(struct sock *sk, struct sk_buff *skb, unsigned int cap);
569 static inline int sk_filter(struct sock *sk, struct sk_buff *skb)
571 return sk_filter_trim_cap(sk, skb, 1);
574 struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err);
575 void bpf_prog_free(struct bpf_prog *fp);
577 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags);
578 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
579 gfp_t gfp_extra_flags);
580 void __bpf_prog_free(struct bpf_prog *fp);
582 static inline void bpf_prog_unlock_free(struct bpf_prog *fp)
584 bpf_prog_unlock_ro(fp);
588 typedef int (*bpf_aux_classic_check_t)(struct sock_filter *filter,
591 int bpf_prog_create(struct bpf_prog **pfp, struct sock_fprog_kern *fprog);
592 int bpf_prog_create_from_user(struct bpf_prog **pfp, struct sock_fprog *fprog,
593 bpf_aux_classic_check_t trans, bool save_orig);
594 void bpf_prog_destroy(struct bpf_prog *fp);
596 int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk);
597 int sk_attach_bpf(u32 ufd, struct sock *sk);
598 int sk_reuseport_attach_filter(struct sock_fprog *fprog, struct sock *sk);
599 int sk_reuseport_attach_bpf(u32 ufd, struct sock *sk);
600 int sk_detach_filter(struct sock *sk);
601 int sk_get_filter(struct sock *sk, struct sock_filter __user *filter,
604 bool sk_filter_charge(struct sock *sk, struct sk_filter *fp);
605 void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp);
607 u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
609 struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog);
610 bool bpf_helper_changes_pkt_data(void *func);
612 struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,
613 const struct bpf_insn *patch, u32 len);
614 void bpf_warn_invalid_xdp_action(u32 act);
616 #ifdef CONFIG_BPF_JIT
617 extern int bpf_jit_enable;
618 extern int bpf_jit_harden;
620 typedef void (*bpf_jit_fill_hole_t)(void *area, unsigned int size);
622 struct bpf_binary_header *
623 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
624 unsigned int alignment,
625 bpf_jit_fill_hole_t bpf_fill_ill_insns);
626 void bpf_jit_binary_free(struct bpf_binary_header *hdr);
628 void bpf_jit_compile(struct bpf_prog *fp);
629 void bpf_jit_free(struct bpf_prog *fp);
631 struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *fp);
632 void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other);
634 static inline void bpf_jit_dump(unsigned int flen, unsigned int proglen,
635 u32 pass, void *image)
637 pr_err("flen=%u proglen=%u pass=%u image=%pK from=%s pid=%d\n", flen,
638 proglen, pass, image, current->comm, task_pid_nr(current));
641 print_hex_dump(KERN_ERR, "JIT code: ", DUMP_PREFIX_OFFSET,
642 16, 1, image, proglen, false);
645 static inline bool bpf_jit_is_ebpf(void)
647 # ifdef CONFIG_HAVE_EBPF_JIT
654 static inline bool bpf_jit_blinding_enabled(void)
656 /* These are the prerequisites, should someone ever have the
657 * idea to call blinding outside of them, we make sure to
660 if (!bpf_jit_is_ebpf())
666 if (bpf_jit_harden == 1 && capable(CAP_SYS_ADMIN))
672 static inline void bpf_jit_compile(struct bpf_prog *fp)
676 static inline void bpf_jit_free(struct bpf_prog *fp)
678 bpf_prog_unlock_free(fp);
680 #endif /* CONFIG_BPF_JIT */
682 #define BPF_ANC BIT(15)
684 static inline bool bpf_needs_clear_a(const struct sock_filter *first)
686 switch (first->code) {
687 case BPF_RET | BPF_K:
688 case BPF_LD | BPF_W | BPF_LEN:
691 case BPF_LD | BPF_W | BPF_ABS:
692 case BPF_LD | BPF_H | BPF_ABS:
693 case BPF_LD | BPF_B | BPF_ABS:
694 if (first->k == SKF_AD_OFF + SKF_AD_ALU_XOR_X)
703 static inline u16 bpf_anc_helper(const struct sock_filter *ftest)
705 BUG_ON(ftest->code & BPF_ANC);
707 switch (ftest->code) {
708 case BPF_LD | BPF_W | BPF_ABS:
709 case BPF_LD | BPF_H | BPF_ABS:
710 case BPF_LD | BPF_B | BPF_ABS:
711 #define BPF_ANCILLARY(CODE) case SKF_AD_OFF + SKF_AD_##CODE: \
712 return BPF_ANC | SKF_AD_##CODE
714 BPF_ANCILLARY(PROTOCOL);
715 BPF_ANCILLARY(PKTTYPE);
716 BPF_ANCILLARY(IFINDEX);
717 BPF_ANCILLARY(NLATTR);
718 BPF_ANCILLARY(NLATTR_NEST);
720 BPF_ANCILLARY(QUEUE);
721 BPF_ANCILLARY(HATYPE);
722 BPF_ANCILLARY(RXHASH);
724 BPF_ANCILLARY(ALU_XOR_X);
725 BPF_ANCILLARY(VLAN_TAG);
726 BPF_ANCILLARY(VLAN_TAG_PRESENT);
727 BPF_ANCILLARY(PAY_OFFSET);
728 BPF_ANCILLARY(RANDOM);
729 BPF_ANCILLARY(VLAN_TPID);
737 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb,
738 int k, unsigned int size);
740 static inline void *bpf_load_pointer(const struct sk_buff *skb, int k,
741 unsigned int size, void *buffer)
744 return skb_header_pointer(skb, k, size, buffer);
746 return bpf_internal_load_pointer_neg_helper(skb, k, size);
749 static inline int bpf_tell_extensions(void)
754 #endif /* __LINUX_FILTER_H__ */