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
16#include <asm/cacheflush.h>
17
18#include <uapi/linux/filter.h>
19#include <uapi/linux/bpf.h>
20
21struct sk_buff;
22struct sock;
23struct seccomp_data;
24struct bpf_prog_aux;
25
26/* ArgX, context and stack frame pointer register positions. Note,
27 * Arg1, Arg2, Arg3, etc are used as argument mappings of function
28 * calls in BPF_CALL instruction.
29 */
30#define BPF_REG_ARG1	BPF_REG_1
31#define BPF_REG_ARG2	BPF_REG_2
32#define BPF_REG_ARG3	BPF_REG_3
33#define BPF_REG_ARG4	BPF_REG_4
34#define BPF_REG_ARG5	BPF_REG_5
35#define BPF_REG_CTX	BPF_REG_6
36#define BPF_REG_FP	BPF_REG_10
37
38/* Additional register mappings for converted user programs. */
39#define BPF_REG_A	BPF_REG_0
40#define BPF_REG_X	BPF_REG_7
41#define BPF_REG_TMP	BPF_REG_8
42
43/* BPF program can access up to 512 bytes of stack space. */
44#define MAX_BPF_STACK	512
45
46/* Helper macros for filter block array initializers. */
47
48/* ALU ops on registers, bpf_add|sub|...: dst_reg += src_reg */
49
50#define BPF_ALU64_REG(OP, DST, SRC)				\
51	((struct bpf_insn) {					\
52		.code  = BPF_ALU64 | BPF_OP(OP) | BPF_X,	\
53		.dst_reg = DST,					\
54		.src_reg = SRC,					\
55		.off   = 0,					\
56		.imm   = 0 })
57
58#define BPF_ALU32_REG(OP, DST, SRC)				\
59	((struct bpf_insn) {					\
60		.code  = BPF_ALU | BPF_OP(OP) | BPF_X,		\
61		.dst_reg = DST,					\
62		.src_reg = SRC,					\
63		.off   = 0,					\
64		.imm   = 0 })
65
66/* ALU ops on immediates, bpf_add|sub|...: dst_reg += imm32 */
67
68#define BPF_ALU64_IMM(OP, DST, IMM)				\
69	((struct bpf_insn) {					\
70		.code  = BPF_ALU64 | BPF_OP(OP) | BPF_K,	\
71		.dst_reg = DST,					\
72		.src_reg = 0,					\
73		.off   = 0,					\
74		.imm   = IMM })
75
76#define BPF_ALU32_IMM(OP, DST, IMM)				\
77	((struct bpf_insn) {					\
78		.code  = BPF_ALU | BPF_OP(OP) | BPF_K,		\
79		.dst_reg = DST,					\
80		.src_reg = 0,					\
81		.off   = 0,					\
82		.imm   = IMM })
83
84/* Endianess conversion, cpu_to_{l,b}e(), {l,b}e_to_cpu() */
85
86#define BPF_ENDIAN(TYPE, DST, LEN)				\
87	((struct bpf_insn) {					\
88		.code  = BPF_ALU | BPF_END | BPF_SRC(TYPE),	\
89		.dst_reg = DST,					\
90		.src_reg = 0,					\
91		.off   = 0,					\
92		.imm   = LEN })
93
94/* Short form of mov, dst_reg = src_reg */
95
96#define BPF_MOV64_REG(DST, SRC)					\
97	((struct bpf_insn) {					\
98		.code  = BPF_ALU64 | BPF_MOV | BPF_X,		\
99		.dst_reg = DST,					\
100		.src_reg = SRC,					\
101		.off   = 0,					\
102		.imm   = 0 })
103
104#define BPF_MOV32_REG(DST, SRC)					\
105	((struct bpf_insn) {					\
106		.code  = BPF_ALU | BPF_MOV | BPF_X,		\
107		.dst_reg = DST,					\
108		.src_reg = SRC,					\
109		.off   = 0,					\
110		.imm   = 0 })
111
112/* Short form of mov, dst_reg = imm32 */
113
114#define BPF_MOV64_IMM(DST, IMM)					\
115	((struct bpf_insn) {					\
116		.code  = BPF_ALU64 | BPF_MOV | BPF_K,		\
117		.dst_reg = DST,					\
118		.src_reg = 0,					\
119		.off   = 0,					\
120		.imm   = IMM })
121
122#define BPF_MOV32_IMM(DST, IMM)					\
123	((struct bpf_insn) {					\
124		.code  = BPF_ALU | BPF_MOV | BPF_K,		\
125		.dst_reg = DST,					\
126		.src_reg = 0,					\
127		.off   = 0,					\
128		.imm   = IMM })
129
130/* BPF_LD_IMM64 macro encodes single 'load 64-bit immediate' insn */
131#define BPF_LD_IMM64(DST, IMM)					\
132	BPF_LD_IMM64_RAW(DST, 0, IMM)
133
134#define BPF_LD_IMM64_RAW(DST, SRC, IMM)				\
135	((struct bpf_insn) {					\
136		.code  = BPF_LD | BPF_DW | BPF_IMM,		\
137		.dst_reg = DST,					\
138		.src_reg = SRC,					\
139		.off   = 0,					\
140		.imm   = (__u32) (IMM) }),			\
141	((struct bpf_insn) {					\
142		.code  = 0, /* zero is reserved opcode */	\
143		.dst_reg = 0,					\
144		.src_reg = 0,					\
145		.off   = 0,					\
146		.imm   = ((__u64) (IMM)) >> 32 })
147
148/* pseudo BPF_LD_IMM64 insn used to refer to process-local map_fd */
149#define BPF_LD_MAP_FD(DST, MAP_FD)				\
150	BPF_LD_IMM64_RAW(DST, BPF_PSEUDO_MAP_FD, MAP_FD)
151
152/* Short form of mov based on type, BPF_X: dst_reg = src_reg, BPF_K: dst_reg = imm32 */
153
154#define BPF_MOV64_RAW(TYPE, DST, SRC, IMM)			\
155	((struct bpf_insn) {					\
156		.code  = BPF_ALU64 | BPF_MOV | BPF_SRC(TYPE),	\
157		.dst_reg = DST,					\
158		.src_reg = SRC,					\
159		.off   = 0,					\
160		.imm   = IMM })
161
162#define BPF_MOV32_RAW(TYPE, DST, SRC, IMM)			\
163	((struct bpf_insn) {					\
164		.code  = BPF_ALU | BPF_MOV | BPF_SRC(TYPE),	\
165		.dst_reg = DST,					\
166		.src_reg = SRC,					\
167		.off   = 0,					\
168		.imm   = IMM })
169
170/* Direct packet access, R0 = *(uint *) (skb->data + imm32) */
171
172#define BPF_LD_ABS(SIZE, IMM)					\
173	((struct bpf_insn) {					\
174		.code  = BPF_LD | BPF_SIZE(SIZE) | BPF_ABS,	\
175		.dst_reg = 0,					\
176		.src_reg = 0,					\
177		.off   = 0,					\
178		.imm   = IMM })
179
180/* Indirect packet access, R0 = *(uint *) (skb->data + src_reg + imm32) */
181
182#define BPF_LD_IND(SIZE, SRC, IMM)				\
183	((struct bpf_insn) {					\
184		.code  = BPF_LD | BPF_SIZE(SIZE) | BPF_IND,	\
185		.dst_reg = 0,					\
186		.src_reg = SRC,					\
187		.off   = 0,					\
188		.imm   = IMM })
189
190/* Memory load, dst_reg = *(uint *) (src_reg + off16) */
191
192#define BPF_LDX_MEM(SIZE, DST, SRC, OFF)			\
193	((struct bpf_insn) {					\
194		.code  = BPF_LDX | BPF_SIZE(SIZE) | BPF_MEM,	\
195		.dst_reg = DST,					\
196		.src_reg = SRC,					\
197		.off   = OFF,					\
198		.imm   = 0 })
199
200/* Memory store, *(uint *) (dst_reg + off16) = src_reg */
201
202#define BPF_STX_MEM(SIZE, DST, SRC, OFF)			\
203	((struct bpf_insn) {					\
204		.code  = BPF_STX | BPF_SIZE(SIZE) | BPF_MEM,	\
205		.dst_reg = DST,					\
206		.src_reg = SRC,					\
207		.off   = OFF,					\
208		.imm   = 0 })
209
210/* Memory store, *(uint *) (dst_reg + off16) = imm32 */
211
212#define BPF_ST_MEM(SIZE, DST, OFF, IMM)				\
213	((struct bpf_insn) {					\
214		.code  = BPF_ST | BPF_SIZE(SIZE) | BPF_MEM,	\
215		.dst_reg = DST,					\
216		.src_reg = 0,					\
217		.off   = OFF,					\
218		.imm   = IMM })
219
220/* Conditional jumps against registers, if (dst_reg 'op' src_reg) goto pc + off16 */
221
222#define BPF_JMP_REG(OP, DST, SRC, OFF)				\
223	((struct bpf_insn) {					\
224		.code  = BPF_JMP | BPF_OP(OP) | BPF_X,		\
225		.dst_reg = DST,					\
226		.src_reg = SRC,					\
227		.off   = OFF,					\
228		.imm   = 0 })
229
230/* Conditional jumps against immediates, if (dst_reg 'op' imm32) goto pc + off16 */
231
232#define BPF_JMP_IMM(OP, DST, IMM, OFF)				\
233	((struct bpf_insn) {					\
234		.code  = BPF_JMP | BPF_OP(OP) | BPF_K,		\
235		.dst_reg = DST,					\
236		.src_reg = 0,					\
237		.off   = OFF,					\
238		.imm   = IMM })
239
240/* Function call */
241
242#define BPF_EMIT_CALL(FUNC)					\
243	((struct bpf_insn) {					\
244		.code  = BPF_JMP | BPF_CALL,			\
245		.dst_reg = 0,					\
246		.src_reg = 0,					\
247		.off   = 0,					\
248		.imm   = ((FUNC) - __bpf_call_base) })
249
250/* Raw code statement block */
251
252#define BPF_RAW_INSN(CODE, DST, SRC, OFF, IMM)			\
253	((struct bpf_insn) {					\
254		.code  = CODE,					\
255		.dst_reg = DST,					\
256		.src_reg = SRC,					\
257		.off   = OFF,					\
258		.imm   = IMM })
259
260/* Program exit */
261
262#define BPF_EXIT_INSN()						\
263	((struct bpf_insn) {					\
264		.code  = BPF_JMP | BPF_EXIT,			\
265		.dst_reg = 0,					\
266		.src_reg = 0,					\
267		.off   = 0,					\
268		.imm   = 0 })
269
270#define bytes_to_bpf_size(bytes)				\
271({								\
272	int bpf_size = -EINVAL;					\
273								\
274	if (bytes == sizeof(u8))				\
275		bpf_size = BPF_B;				\
276	else if (bytes == sizeof(u16))				\
277		bpf_size = BPF_H;				\
278	else if (bytes == sizeof(u32))				\
279		bpf_size = BPF_W;				\
280	else if (bytes == sizeof(u64))				\
281		bpf_size = BPF_DW;				\
282								\
283	bpf_size;						\
284})
285
286/* Macro to invoke filter function. */
287#define SK_RUN_FILTER(filter, ctx) \
288	(*filter->prog->bpf_func)(ctx, filter->prog->insnsi)
289
290#ifdef CONFIG_COMPAT
291/* A struct sock_filter is architecture independent. */
292struct compat_sock_fprog {
293	u16		len;
294	compat_uptr_t	filter;	/* struct sock_filter * */
295};
296#endif
297
298struct sock_fprog_kern {
299	u16			len;
300	struct sock_filter	*filter;
301};
302
303struct bpf_binary_header {
304	unsigned int pages;
305	u8 image[];
306};
307
308struct bpf_prog {
309	u16			pages;		/* Number of allocated pages */
310	bool			jited;		/* Is our filter JIT'ed? */
311	bool			gpl_compatible;	/* Is our filter GPL compatible? */
312	u32			len;		/* Number of filter blocks */
313	enum bpf_prog_type	type;		/* Type of BPF program */
314	struct bpf_prog_aux	*aux;		/* Auxiliary fields */
315	struct sock_fprog_kern	*orig_prog;	/* Original BPF program */
316	unsigned int		(*bpf_func)(const struct sk_buff *skb,
317					    const struct bpf_insn *filter);
318	/* Instructions for interpreter */
319	union {
320		struct sock_filter	insns[0];
321		struct bpf_insn		insnsi[0];
322	};
323};
324
325struct sk_filter {
326	atomic_t	refcnt;
327	struct rcu_head	rcu;
328	struct bpf_prog	*prog;
329};
330
331#define BPF_PROG_RUN(filter, ctx)  (*filter->bpf_func)(ctx, filter->insnsi)
332
333static inline unsigned int bpf_prog_size(unsigned int proglen)
334{
335	return max(sizeof(struct bpf_prog),
336		   offsetof(struct bpf_prog, insns[proglen]));
337}
338
339#define bpf_classic_proglen(fprog) (fprog->len * sizeof(fprog->filter[0]))
340
341#ifdef CONFIG_DEBUG_SET_MODULE_RONX
342static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
343{
344	set_memory_ro((unsigned long)fp, fp->pages);
345}
346
347static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
348{
349	set_memory_rw((unsigned long)fp, fp->pages);
350}
351#else
352static inline void bpf_prog_lock_ro(struct bpf_prog *fp)
353{
354}
355
356static inline void bpf_prog_unlock_ro(struct bpf_prog *fp)
357{
358}
359#endif /* CONFIG_DEBUG_SET_MODULE_RONX */
360
361int sk_filter(struct sock *sk, struct sk_buff *skb);
362
363void bpf_prog_select_runtime(struct bpf_prog *fp);
364void bpf_prog_free(struct bpf_prog *fp);
365
366int bpf_convert_filter(struct sock_filter *prog, int len,
367		       struct bpf_insn *new_prog, int *new_len);
368
369struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags);
370struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
371				  gfp_t gfp_extra_flags);
372void __bpf_prog_free(struct bpf_prog *fp);
373
374static inline void bpf_prog_unlock_free(struct bpf_prog *fp)
375{
376	bpf_prog_unlock_ro(fp);
377	__bpf_prog_free(fp);
378}
379
380int bpf_prog_create(struct bpf_prog **pfp, struct sock_fprog_kern *fprog);
381void bpf_prog_destroy(struct bpf_prog *fp);
382
383int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk);
384int sk_attach_bpf(u32 ufd, struct sock *sk);
385int sk_detach_filter(struct sock *sk);
386
387int bpf_check_classic(const struct sock_filter *filter, unsigned int flen);
388int sk_get_filter(struct sock *sk, struct sock_filter __user *filter,
389		  unsigned int len);
390
391bool sk_filter_charge(struct sock *sk, struct sk_filter *fp);
392void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp);
393
394u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
395void bpf_int_jit_compile(struct bpf_prog *fp);
396
397#ifdef CONFIG_BPF_JIT
398typedef void (*bpf_jit_fill_hole_t)(void *area, unsigned int size);
399
400struct bpf_binary_header *
401bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
402		     unsigned int alignment,
403		     bpf_jit_fill_hole_t bpf_fill_ill_insns);
404void bpf_jit_binary_free(struct bpf_binary_header *hdr);
405
406void bpf_jit_compile(struct bpf_prog *fp);
407void bpf_jit_free(struct bpf_prog *fp);
408
409static inline void bpf_jit_dump(unsigned int flen, unsigned int proglen,
410				u32 pass, void *image)
411{
412	pr_err("flen=%u proglen=%u pass=%u image=%pK\n",
413	       flen, proglen, pass, image);
414	if (image)
415		print_hex_dump(KERN_ERR, "JIT code: ", DUMP_PREFIX_OFFSET,
416			       16, 1, image, proglen, false);
417}
418#else
419static inline void bpf_jit_compile(struct bpf_prog *fp)
420{
421}
422
423static inline void bpf_jit_free(struct bpf_prog *fp)
424{
425	bpf_prog_unlock_free(fp);
426}
427#endif /* CONFIG_BPF_JIT */
428
429#define BPF_ANC		BIT(15)
430
431static inline bool bpf_needs_clear_a(const struct sock_filter *first)
432{
433	switch (first->code) {
434	case BPF_RET | BPF_K:
435	case BPF_LD | BPF_W | BPF_LEN:
436		return false;
437
438	case BPF_LD | BPF_W | BPF_ABS:
439	case BPF_LD | BPF_H | BPF_ABS:
440	case BPF_LD | BPF_B | BPF_ABS:
441		if (first->k == SKF_AD_OFF + SKF_AD_ALU_XOR_X)
442			return true;
443		return false;
444
445	default:
446		return true;
447	}
448}
449
450static inline u16 bpf_anc_helper(const struct sock_filter *ftest)
451{
452	BUG_ON(ftest->code & BPF_ANC);
453
454	switch (ftest->code) {
455	case BPF_LD | BPF_W | BPF_ABS:
456	case BPF_LD | BPF_H | BPF_ABS:
457	case BPF_LD | BPF_B | BPF_ABS:
458#define BPF_ANCILLARY(CODE)	case SKF_AD_OFF + SKF_AD_##CODE:	\
459				return BPF_ANC | SKF_AD_##CODE
460		switch (ftest->k) {
461		BPF_ANCILLARY(PROTOCOL);
462		BPF_ANCILLARY(PKTTYPE);
463		BPF_ANCILLARY(IFINDEX);
464		BPF_ANCILLARY(NLATTR);
465		BPF_ANCILLARY(NLATTR_NEST);
466		BPF_ANCILLARY(MARK);
467		BPF_ANCILLARY(QUEUE);
468		BPF_ANCILLARY(HATYPE);
469		BPF_ANCILLARY(RXHASH);
470		BPF_ANCILLARY(CPU);
471		BPF_ANCILLARY(ALU_XOR_X);
472		BPF_ANCILLARY(VLAN_TAG);
473		BPF_ANCILLARY(VLAN_TAG_PRESENT);
474		BPF_ANCILLARY(PAY_OFFSET);
475		BPF_ANCILLARY(RANDOM);
476		BPF_ANCILLARY(VLAN_TPID);
477		}
478		/* Fallthrough. */
479	default:
480		return ftest->code;
481	}
482}
483
484void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb,
485					   int k, unsigned int size);
486
487static inline void *bpf_load_pointer(const struct sk_buff *skb, int k,
488				     unsigned int size, void *buffer)
489{
490	if (k >= 0)
491		return skb_header_pointer(skb, k, size, buffer);
492
493	return bpf_internal_load_pointer_neg_helper(skb, k, size);
494}
495
496static inline int bpf_tell_extensions(void)
497{
498	return SKF_AD_MAX;
499}
500
501#endif /* __LINUX_FILTER_H__ */
502