xref: /linux-6.15/include/linux/filter.h (revision 0f06a678)
1 /*
2  * Linux Socket Filter Data Structures
3  */
4 #ifndef __LINUX_FILTER_H__
5 #define __LINUX_FILTER_H__
6 
7 #include <stdarg.h>
8 
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 
18 #include <net/sch_generic.h>
19 
20 #include <asm/cacheflush.h>
21 
22 #include <uapi/linux/filter.h>
23 #include <uapi/linux/bpf.h>
24 
25 struct sk_buff;
26 struct sock;
27 struct seccomp_data;
28 struct bpf_prog_aux;
29 
30 /* ArgX, context and stack frame pointer register positions. Note,
31  * Arg1, Arg2, Arg3, etc are used as argument mappings of function
32  * calls in BPF_CALL instruction.
33  */
34 #define BPF_REG_ARG1	BPF_REG_1
35 #define BPF_REG_ARG2	BPF_REG_2
36 #define BPF_REG_ARG3	BPF_REG_3
37 #define BPF_REG_ARG4	BPF_REG_4
38 #define BPF_REG_ARG5	BPF_REG_5
39 #define BPF_REG_CTX	BPF_REG_6
40 #define BPF_REG_FP	BPF_REG_10
41 
42 /* Additional register mappings for converted user programs. */
43 #define BPF_REG_A	BPF_REG_0
44 #define BPF_REG_X	BPF_REG_7
45 #define BPF_REG_TMP	BPF_REG_8
46 
47 /* Kernel hidden auxiliary/helper register for hardening step.
48  * Only used by eBPF JITs. It's nothing more than a temporary
49  * register that JITs use internally, only that here it's part
50  * of eBPF instructions that have been rewritten for blinding
51  * constants. See JIT pre-step in bpf_jit_blind_constants().
52  */
53 #define BPF_REG_AX		MAX_BPF_REG
54 #define MAX_BPF_JIT_REG		(MAX_BPF_REG + 1)
55 
56 /* BPF program can access up to 512 bytes of stack space. */
57 #define MAX_BPF_STACK	512
58 
59 /* Helper macros for filter block array initializers. */
60 
61 /* ALU ops on registers, bpf_add|sub|...: dst_reg += src_reg */
62 
63 #define BPF_ALU64_REG(OP, DST, SRC)				\
64 	((struct bpf_insn) {					\
65 		.code  = BPF_ALU64 | BPF_OP(OP) | BPF_X,	\
66 		.dst_reg = DST,					\
67 		.src_reg = SRC,					\
68 		.off   = 0,					\
69 		.imm   = 0 })
70 
71 #define BPF_ALU32_REG(OP, DST, SRC)				\
72 	((struct bpf_insn) {					\
73 		.code  = BPF_ALU | BPF_OP(OP) | BPF_X,		\
74 		.dst_reg = DST,					\
75 		.src_reg = SRC,					\
76 		.off   = 0,					\
77 		.imm   = 0 })
78 
79 /* ALU ops on immediates, bpf_add|sub|...: dst_reg += imm32 */
80 
81 #define BPF_ALU64_IMM(OP, DST, IMM)				\
82 	((struct bpf_insn) {					\
83 		.code  = BPF_ALU64 | BPF_OP(OP) | BPF_K,	\
84 		.dst_reg = DST,					\
85 		.src_reg = 0,					\
86 		.off   = 0,					\
87 		.imm   = IMM })
88 
89 #define BPF_ALU32_IMM(OP, DST, IMM)				\
90 	((struct bpf_insn) {					\
91 		.code  = BPF_ALU | BPF_OP(OP) | BPF_K,		\
92 		.dst_reg = DST,					\
93 		.src_reg = 0,					\
94 		.off   = 0,					\
95 		.imm   = IMM })
96 
97 /* Endianess conversion, cpu_to_{l,b}e(), {l,b}e_to_cpu() */
98 
99 #define BPF_ENDIAN(TYPE, DST, LEN)				\
100 	((struct bpf_insn) {					\
101 		.code  = BPF_ALU | BPF_END | BPF_SRC(TYPE),	\
102 		.dst_reg = DST,					\
103 		.src_reg = 0,					\
104 		.off   = 0,					\
105 		.imm   = LEN })
106 
107 /* Short form of mov, dst_reg = src_reg */
108 
109 #define BPF_MOV64_REG(DST, SRC)					\
110 	((struct bpf_insn) {					\
111 		.code  = BPF_ALU64 | BPF_MOV | BPF_X,		\
112 		.dst_reg = DST,					\
113 		.src_reg = SRC,					\
114 		.off   = 0,					\
115 		.imm   = 0 })
116 
117 #define BPF_MOV32_REG(DST, SRC)					\
118 	((struct bpf_insn) {					\
119 		.code  = BPF_ALU | BPF_MOV | BPF_X,		\
120 		.dst_reg = DST,					\
121 		.src_reg = SRC,					\
122 		.off   = 0,					\
123 		.imm   = 0 })
124 
125 /* Short form of mov, dst_reg = imm32 */
126 
127 #define BPF_MOV64_IMM(DST, IMM)					\
128 	((struct bpf_insn) {					\
129 		.code  = BPF_ALU64 | BPF_MOV | BPF_K,		\
130 		.dst_reg = DST,					\
131 		.src_reg = 0,					\
132 		.off   = 0,					\
133 		.imm   = IMM })
134 
135 #define BPF_MOV32_IMM(DST, IMM)					\
136 	((struct bpf_insn) {					\
137 		.code  = BPF_ALU | BPF_MOV | BPF_K,		\
138 		.dst_reg = DST,					\
139 		.src_reg = 0,					\
140 		.off   = 0,					\
141 		.imm   = IMM })
142 
143 /* BPF_LD_IMM64 macro encodes single 'load 64-bit immediate' insn */
144 #define BPF_LD_IMM64(DST, IMM)					\
145 	BPF_LD_IMM64_RAW(DST, 0, IMM)
146 
147 #define BPF_LD_IMM64_RAW(DST, SRC, IMM)				\
148 	((struct bpf_insn) {					\
149 		.code  = BPF_LD | BPF_DW | BPF_IMM,		\
150 		.dst_reg = DST,					\
151 		.src_reg = SRC,					\
152 		.off   = 0,					\
153 		.imm   = (__u32) (IMM) }),			\
154 	((struct bpf_insn) {					\
155 		.code  = 0, /* zero is reserved opcode */	\
156 		.dst_reg = 0,					\
157 		.src_reg = 0,					\
158 		.off   = 0,					\
159 		.imm   = ((__u64) (IMM)) >> 32 })
160 
161 /* pseudo BPF_LD_IMM64 insn used to refer to process-local map_fd */
162 #define BPF_LD_MAP_FD(DST, MAP_FD)				\
163 	BPF_LD_IMM64_RAW(DST, BPF_PSEUDO_MAP_FD, MAP_FD)
164 
165 /* Short form of mov based on type, BPF_X: dst_reg = src_reg, BPF_K: dst_reg = imm32 */
166 
167 #define BPF_MOV64_RAW(TYPE, DST, SRC, IMM)			\
168 	((struct bpf_insn) {					\
169 		.code  = BPF_ALU64 | BPF_MOV | BPF_SRC(TYPE),	\
170 		.dst_reg = DST,					\
171 		.src_reg = SRC,					\
172 		.off   = 0,					\
173 		.imm   = IMM })
174 
175 #define BPF_MOV32_RAW(TYPE, DST, SRC, IMM)			\
176 	((struct bpf_insn) {					\
177 		.code  = BPF_ALU | BPF_MOV | BPF_SRC(TYPE),	\
178 		.dst_reg = DST,					\
179 		.src_reg = SRC,					\
180 		.off   = 0,					\
181 		.imm   = IMM })
182 
183 /* Direct packet access, R0 = *(uint *) (skb->data + imm32) */
184 
185 #define BPF_LD_ABS(SIZE, IMM)					\
186 	((struct bpf_insn) {					\
187 		.code  = BPF_LD | BPF_SIZE(SIZE) | BPF_ABS,	\
188 		.dst_reg = 0,					\
189 		.src_reg = 0,					\
190 		.off   = 0,					\
191 		.imm   = IMM })
192 
193 /* Indirect packet access, R0 = *(uint *) (skb->data + src_reg + imm32) */
194 
195 #define BPF_LD_IND(SIZE, SRC, IMM)				\
196 	((struct bpf_insn) {					\
197 		.code  = BPF_LD | BPF_SIZE(SIZE) | BPF_IND,	\
198 		.dst_reg = 0,					\
199 		.src_reg = SRC,					\
200 		.off   = 0,					\
201 		.imm   = IMM })
202 
203 /* Memory load, dst_reg = *(uint *) (src_reg + off16) */
204 
205 #define BPF_LDX_MEM(SIZE, DST, SRC, OFF)			\
206 	((struct bpf_insn) {					\
207 		.code  = BPF_LDX | BPF_SIZE(SIZE) | BPF_MEM,	\
208 		.dst_reg = DST,					\
209 		.src_reg = SRC,					\
210 		.off   = OFF,					\
211 		.imm   = 0 })
212 
213 /* Memory store, *(uint *) (dst_reg + off16) = src_reg */
214 
215 #define BPF_STX_MEM(SIZE, DST, SRC, OFF)			\
216 	((struct bpf_insn) {					\
217 		.code  = BPF_STX | BPF_SIZE(SIZE) | BPF_MEM,	\
218 		.dst_reg = DST,					\
219 		.src_reg = SRC,					\
220 		.off   = OFF,					\
221 		.imm   = 0 })
222 
223 /* Atomic memory add, *(uint *)(dst_reg + off16) += src_reg */
224 
225 #define BPF_STX_XADD(SIZE, DST, SRC, OFF)			\
226 	((struct bpf_insn) {					\
227 		.code  = BPF_STX | BPF_SIZE(SIZE) | BPF_XADD,	\
228 		.dst_reg = DST,					\
229 		.src_reg = SRC,					\
230 		.off   = OFF,					\
231 		.imm   = 0 })
232 
233 /* Memory store, *(uint *) (dst_reg + off16) = imm32 */
234 
235 #define BPF_ST_MEM(SIZE, DST, OFF, IMM)				\
236 	((struct bpf_insn) {					\
237 		.code  = BPF_ST | BPF_SIZE(SIZE) | BPF_MEM,	\
238 		.dst_reg = DST,					\
239 		.src_reg = 0,					\
240 		.off   = OFF,					\
241 		.imm   = IMM })
242 
243 /* Conditional jumps against registers, if (dst_reg 'op' src_reg) goto pc + off16 */
244 
245 #define BPF_JMP_REG(OP, DST, SRC, OFF)				\
246 	((struct bpf_insn) {					\
247 		.code  = BPF_JMP | BPF_OP(OP) | BPF_X,		\
248 		.dst_reg = DST,					\
249 		.src_reg = SRC,					\
250 		.off   = OFF,					\
251 		.imm   = 0 })
252 
253 /* Conditional jumps against immediates, if (dst_reg 'op' imm32) goto pc + off16 */
254 
255 #define BPF_JMP_IMM(OP, DST, IMM, OFF)				\
256 	((struct bpf_insn) {					\
257 		.code  = BPF_JMP | BPF_OP(OP) | BPF_K,		\
258 		.dst_reg = DST,					\
259 		.src_reg = 0,					\
260 		.off   = OFF,					\
261 		.imm   = IMM })
262 
263 /* Function call */
264 
265 #define BPF_EMIT_CALL(FUNC)					\
266 	((struct bpf_insn) {					\
267 		.code  = BPF_JMP | BPF_CALL,			\
268 		.dst_reg = 0,					\
269 		.src_reg = 0,					\
270 		.off   = 0,					\
271 		.imm   = ((FUNC) - __bpf_call_base) })
272 
273 /* Raw code statement block */
274 
275 #define BPF_RAW_INSN(CODE, DST, SRC, OFF, IMM)			\
276 	((struct bpf_insn) {					\
277 		.code  = CODE,					\
278 		.dst_reg = DST,					\
279 		.src_reg = SRC,					\
280 		.off   = OFF,					\
281 		.imm   = IMM })
282 
283 /* Program exit */
284 
285 #define BPF_EXIT_INSN()						\
286 	((struct bpf_insn) {					\
287 		.code  = BPF_JMP | BPF_EXIT,			\
288 		.dst_reg = 0,					\
289 		.src_reg = 0,					\
290 		.off   = 0,					\
291 		.imm   = 0 })
292 
293 /* Internal classic blocks for direct assignment */
294 
295 #define __BPF_STMT(CODE, K)					\
296 	((struct sock_filter) BPF_STMT(CODE, K))
297 
298 #define __BPF_JUMP(CODE, K, JT, JF)				\
299 	((struct sock_filter) BPF_JUMP(CODE, K, JT, JF))
300 
301 #define bytes_to_bpf_size(bytes)				\
302 ({								\
303 	int bpf_size = -EINVAL;					\
304 								\
305 	if (bytes == sizeof(u8))				\
306 		bpf_size = BPF_B;				\
307 	else if (bytes == sizeof(u16))				\
308 		bpf_size = BPF_H;				\
309 	else if (bytes == sizeof(u32))				\
310 		bpf_size = BPF_W;				\
311 	else if (bytes == sizeof(u64))				\
312 		bpf_size = BPF_DW;				\
313 								\
314 	bpf_size;						\
315 })
316 
317 #ifdef CONFIG_COMPAT
318 /* A struct sock_filter is architecture independent. */
319 struct compat_sock_fprog {
320 	u16		len;
321 	compat_uptr_t	filter;	/* struct sock_filter * */
322 };
323 #endif
324 
325 struct sock_fprog_kern {
326 	u16			len;
327 	struct sock_filter	*filter;
328 };
329 
330 struct bpf_binary_header {
331 	unsigned int pages;
332 	u8 image[];
333 };
334 
335 struct bpf_prog {
336 	u16			pages;		/* Number of allocated pages */
337 	kmemcheck_bitfield_begin(meta);
338 	u16			jited:1,	/* Is our filter JIT'ed? */
339 				gpl_compatible:1, /* Is filter GPL compatible? */
340 				cb_access:1,	/* Is control block accessed? */
341 				dst_needed:1;	/* Do we need dst entry? */
342 	kmemcheck_bitfield_end(meta);
343 	u32			len;		/* Number of filter blocks */
344 	enum bpf_prog_type	type;		/* Type of BPF program */
345 	struct bpf_prog_aux	*aux;		/* Auxiliary fields */
346 	struct sock_fprog_kern	*orig_prog;	/* Original BPF program */
347 	unsigned int		(*bpf_func)(const struct sk_buff *skb,
348 					    const struct bpf_insn *filter);
349 	/* Instructions for interpreter */
350 	union {
351 		struct sock_filter	insns[0];
352 		struct bpf_insn		insnsi[0];
353 	};
354 };
355 
356 struct sk_filter {
357 	atomic_t	refcnt;
358 	struct rcu_head	rcu;
359 	struct bpf_prog	*prog;
360 };
361 
362 #define BPF_PROG_RUN(filter, ctx)  (*filter->bpf_func)(ctx, filter->insnsi)
363 
364 #define BPF_SKB_CB_LEN QDISC_CB_PRIV_LEN
365 
366 struct bpf_skb_data_end {
367 	struct qdisc_skb_cb qdisc_cb;
368 	void *data_end;
369 };
370 
371 struct xdp_buff {
372 	void *data;
373 	void *data_end;
374 };
375 
376 /* compute the linear packet data range [data, data_end) which
377  * will be accessed by cls_bpf and act_bpf programs
378  */
379 static inline void bpf_compute_data_end(struct sk_buff *skb)
380 {
381 	struct bpf_skb_data_end *cb = (struct bpf_skb_data_end *)skb->cb;
382 
383 	BUILD_BUG_ON(sizeof(*cb) > FIELD_SIZEOF(struct sk_buff, cb));
384 	cb->data_end = skb->data + skb_headlen(skb);
385 }
386 
387 static inline u8 *bpf_skb_cb(struct sk_buff *skb)
388 {
389 	/* eBPF programs may read/write skb->cb[] area to transfer meta
390 	 * data between tail calls. Since this also needs to work with
391 	 * tc, that scratch memory is mapped to qdisc_skb_cb's data area.
392 	 *
393 	 * In some socket filter cases, the cb unfortunately needs to be
394 	 * saved/restored so that protocol specific skb->cb[] data won't
395 	 * be lost. In any case, due to unpriviledged eBPF programs
396 	 * attached to sockets, we need to clear the bpf_skb_cb() area
397 	 * to not leak previous contents to user space.
398 	 */
399 	BUILD_BUG_ON(FIELD_SIZEOF(struct __sk_buff, cb) != BPF_SKB_CB_LEN);
400 	BUILD_BUG_ON(FIELD_SIZEOF(struct __sk_buff, cb) !=
401 		     FIELD_SIZEOF(struct qdisc_skb_cb, data));
402 
403 	return qdisc_skb_cb(skb)->data;
404 }
405 
406 static inline u32 bpf_prog_run_save_cb(const struct bpf_prog *prog,
407 				       struct sk_buff *skb)
408 {
409 	u8 *cb_data = bpf_skb_cb(skb);
410 	u8 cb_saved[BPF_SKB_CB_LEN];
411 	u32 res;
412 
413 	if (unlikely(prog->cb_access)) {
414 		memcpy(cb_saved, cb_data, sizeof(cb_saved));
415 		memset(cb_data, 0, sizeof(cb_saved));
416 	}
417 
418 	res = BPF_PROG_RUN(prog, skb);
419 
420 	if (unlikely(prog->cb_access))
421 		memcpy(cb_data, cb_saved, sizeof(cb_saved));
422 
423 	return res;
424 }
425 
426 static inline u32 bpf_prog_run_clear_cb(const struct bpf_prog *prog,
427 					struct sk_buff *skb)
428 {
429 	u8 *cb_data = bpf_skb_cb(skb);
430 
431 	if (unlikely(prog->cb_access))
432 		memset(cb_data, 0, BPF_SKB_CB_LEN);
433 
434 	return BPF_PROG_RUN(prog, skb);
435 }
436 
437 static inline u32 bpf_prog_run_xdp(const struct bpf_prog *prog,
438 				   struct xdp_buff *xdp)
439 {
440 	u32 ret;
441 
442 	rcu_read_lock();
443 	ret = BPF_PROG_RUN(prog, (void *)xdp);
444 	rcu_read_unlock();
445 
446 	return ret;
447 }
448 
449 static inline unsigned int bpf_prog_size(unsigned int proglen)
450 {
451 	return max(sizeof(struct bpf_prog),
452 		   offsetof(struct bpf_prog, insns[proglen]));
453 }
454 
455 static inline bool bpf_prog_was_classic(const struct bpf_prog *prog)
456 {
457 	/* When classic BPF programs have been loaded and the arch
458 	 * does not have a classic BPF JIT (anymore), they have been
459 	 * converted via bpf_migrate_filter() to eBPF and thus always
460 	 * have an unspec program type.
461 	 */
462 	return prog->type == BPF_PROG_TYPE_UNSPEC;
463 }
464 
465 #define bpf_classic_proglen(fprog) (fprog->len * sizeof(fprog->filter[0]))
466 
467 #ifdef CONFIG_DEBUG_SET_MODULE_RONX
468 static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
469 {
470 	set_memory_ro((unsigned long)fp, fp->pages);
471 }
472 
473 static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
474 {
475 	set_memory_rw((unsigned long)fp, fp->pages);
476 }
477 #else
478 static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
479 {
480 }
481 
482 static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
483 {
484 }
485 #endif /* CONFIG_DEBUG_SET_MODULE_RONX */
486 
487 int sk_filter(struct sock *sk, struct sk_buff *skb);
488 
489 struct bpf_prog *bpf_prog_select_runtime(struct bpf_prog *fp, int *err);
490 void bpf_prog_free(struct bpf_prog *fp);
491 
492 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags);
493 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
494 				  gfp_t gfp_extra_flags);
495 void __bpf_prog_free(struct bpf_prog *fp);
496 
497 static inline void bpf_prog_unlock_free(struct bpf_prog *fp)
498 {
499 	bpf_prog_unlock_ro(fp);
500 	__bpf_prog_free(fp);
501 }
502 
503 typedef int (*bpf_aux_classic_check_t)(struct sock_filter *filter,
504 				       unsigned int flen);
505 
506 int bpf_prog_create(struct bpf_prog **pfp, struct sock_fprog_kern *fprog);
507 int bpf_prog_create_from_user(struct bpf_prog **pfp, struct sock_fprog *fprog,
508 			      bpf_aux_classic_check_t trans, bool save_orig);
509 void bpf_prog_destroy(struct bpf_prog *fp);
510 
511 int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk);
512 int sk_attach_bpf(u32 ufd, struct sock *sk);
513 int sk_reuseport_attach_filter(struct sock_fprog *fprog, struct sock *sk);
514 int sk_reuseport_attach_bpf(u32 ufd, struct sock *sk);
515 int sk_detach_filter(struct sock *sk);
516 int sk_get_filter(struct sock *sk, struct sock_filter __user *filter,
517 		  unsigned int len);
518 
519 bool sk_filter_charge(struct sock *sk, struct sk_filter *fp);
520 void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp);
521 
522 u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
523 
524 struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog);
525 bool bpf_helper_changes_skb_data(void *func);
526 
527 struct bpf_prog *bpf_patch_insn_single(struct bpf_prog *prog, u32 off,
528 				       const struct bpf_insn *patch, u32 len);
529 void bpf_warn_invalid_xdp_action(u32 act);
530 
531 #ifdef CONFIG_BPF_JIT
532 extern int bpf_jit_enable;
533 extern int bpf_jit_harden;
534 
535 typedef void (*bpf_jit_fill_hole_t)(void *area, unsigned int size);
536 
537 struct bpf_binary_header *
538 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
539 		     unsigned int alignment,
540 		     bpf_jit_fill_hole_t bpf_fill_ill_insns);
541 void bpf_jit_binary_free(struct bpf_binary_header *hdr);
542 
543 void bpf_jit_compile(struct bpf_prog *fp);
544 void bpf_jit_free(struct bpf_prog *fp);
545 
546 struct bpf_prog *bpf_jit_blind_constants(struct bpf_prog *fp);
547 void bpf_jit_prog_release_other(struct bpf_prog *fp, struct bpf_prog *fp_other);
548 
549 static inline void bpf_jit_dump(unsigned int flen, unsigned int proglen,
550 				u32 pass, void *image)
551 {
552 	pr_err("flen=%u proglen=%u pass=%u image=%pK from=%s pid=%d\n", flen,
553 	       proglen, pass, image, current->comm, task_pid_nr(current));
554 
555 	if (image)
556 		print_hex_dump(KERN_ERR, "JIT code: ", DUMP_PREFIX_OFFSET,
557 			       16, 1, image, proglen, false);
558 }
559 
560 static inline bool bpf_jit_is_ebpf(void)
561 {
562 # ifdef CONFIG_HAVE_EBPF_JIT
563 	return true;
564 # else
565 	return false;
566 # endif
567 }
568 
569 static inline bool bpf_jit_blinding_enabled(void)
570 {
571 	/* These are the prerequisites, should someone ever have the
572 	 * idea to call blinding outside of them, we make sure to
573 	 * bail out.
574 	 */
575 	if (!bpf_jit_is_ebpf())
576 		return false;
577 	if (!bpf_jit_enable)
578 		return false;
579 	if (!bpf_jit_harden)
580 		return false;
581 	if (bpf_jit_harden == 1 && capable(CAP_SYS_ADMIN))
582 		return false;
583 
584 	return true;
585 }
586 #else
587 static inline void bpf_jit_compile(struct bpf_prog *fp)
588 {
589 }
590 
591 static inline void bpf_jit_free(struct bpf_prog *fp)
592 {
593 	bpf_prog_unlock_free(fp);
594 }
595 #endif /* CONFIG_BPF_JIT */
596 
597 #define BPF_ANC		BIT(15)
598 
599 static inline bool bpf_needs_clear_a(const struct sock_filter *first)
600 {
601 	switch (first->code) {
602 	case BPF_RET | BPF_K:
603 	case BPF_LD | BPF_W | BPF_LEN:
604 		return false;
605 
606 	case BPF_LD | BPF_W | BPF_ABS:
607 	case BPF_LD | BPF_H | BPF_ABS:
608 	case BPF_LD | BPF_B | BPF_ABS:
609 		if (first->k == SKF_AD_OFF + SKF_AD_ALU_XOR_X)
610 			return true;
611 		return false;
612 
613 	default:
614 		return true;
615 	}
616 }
617 
618 static inline u16 bpf_anc_helper(const struct sock_filter *ftest)
619 {
620 	BUG_ON(ftest->code & BPF_ANC);
621 
622 	switch (ftest->code) {
623 	case BPF_LD | BPF_W | BPF_ABS:
624 	case BPF_LD | BPF_H | BPF_ABS:
625 	case BPF_LD | BPF_B | BPF_ABS:
626 #define BPF_ANCILLARY(CODE)	case SKF_AD_OFF + SKF_AD_##CODE:	\
627 				return BPF_ANC | SKF_AD_##CODE
628 		switch (ftest->k) {
629 		BPF_ANCILLARY(PROTOCOL);
630 		BPF_ANCILLARY(PKTTYPE);
631 		BPF_ANCILLARY(IFINDEX);
632 		BPF_ANCILLARY(NLATTR);
633 		BPF_ANCILLARY(NLATTR_NEST);
634 		BPF_ANCILLARY(MARK);
635 		BPF_ANCILLARY(QUEUE);
636 		BPF_ANCILLARY(HATYPE);
637 		BPF_ANCILLARY(RXHASH);
638 		BPF_ANCILLARY(CPU);
639 		BPF_ANCILLARY(ALU_XOR_X);
640 		BPF_ANCILLARY(VLAN_TAG);
641 		BPF_ANCILLARY(VLAN_TAG_PRESENT);
642 		BPF_ANCILLARY(PAY_OFFSET);
643 		BPF_ANCILLARY(RANDOM);
644 		BPF_ANCILLARY(VLAN_TPID);
645 		}
646 		/* Fallthrough. */
647 	default:
648 		return ftest->code;
649 	}
650 }
651 
652 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb,
653 					   int k, unsigned int size);
654 
655 static inline void *bpf_load_pointer(const struct sk_buff *skb, int k,
656 				     unsigned int size, void *buffer)
657 {
658 	if (k >= 0)
659 		return skb_header_pointer(skb, k, size, buffer);
660 
661 	return bpf_internal_load_pointer_neg_helper(skb, k, size);
662 }
663 
664 static inline int bpf_tell_extensions(void)
665 {
666 	return SKF_AD_MAX;
667 }
668 
669 #endif /* __LINUX_FILTER_H__ */
670