Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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kernel
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linux
1/*
2 * Linux Socket Filter Data Structures
3 */
4#ifndef __LINUX_FILTER_H__
5#define __LINUX_FILTER_H__
6
7#include <linux/atomic.h>
8#include <linux/compat.h>
9#include <linux/skbuff.h>
10#include <linux/workqueue.h>
11#include <uapi/linux/filter.h>
12
13/* Internally used and optimized filter representation with extended
14 * instruction set based on top of classic BPF.
15 */
16
17/* instruction classes */
18#define BPF_ALU64 0x07 /* alu mode in double word width */
19
20/* ld/ldx fields */
21#define BPF_DW 0x18 /* double word */
22#define BPF_XADD 0xc0 /* exclusive add */
23
24/* alu/jmp fields */
25#define BPF_MOV 0xb0 /* mov reg to reg */
26#define BPF_ARSH 0xc0 /* sign extending arithmetic shift right */
27
28/* change endianness of a register */
29#define BPF_END 0xd0 /* flags for endianness conversion: */
30#define BPF_TO_LE 0x00 /* convert to little-endian */
31#define BPF_TO_BE 0x08 /* convert to big-endian */
32#define BPF_FROM_LE BPF_TO_LE
33#define BPF_FROM_BE BPF_TO_BE
34
35#define BPF_JNE 0x50 /* jump != */
36#define BPF_JSGT 0x60 /* SGT is signed '>', GT in x86 */
37#define BPF_JSGE 0x70 /* SGE is signed '>=', GE in x86 */
38#define BPF_CALL 0x80 /* function call */
39#define BPF_EXIT 0x90 /* function return */
40
41/* Register numbers */
42enum {
43 BPF_REG_0 = 0,
44 BPF_REG_1,
45 BPF_REG_2,
46 BPF_REG_3,
47 BPF_REG_4,
48 BPF_REG_5,
49 BPF_REG_6,
50 BPF_REG_7,
51 BPF_REG_8,
52 BPF_REG_9,
53 BPF_REG_10,
54 __MAX_BPF_REG,
55};
56
57/* BPF has 10 general purpose 64-bit registers and stack frame. */
58#define MAX_BPF_REG __MAX_BPF_REG
59
60/* ArgX, context and stack frame pointer register positions. Note,
61 * Arg1, Arg2, Arg3, etc are used as argument mappings of function
62 * calls in BPF_CALL instruction.
63 */
64#define BPF_REG_ARG1 BPF_REG_1
65#define BPF_REG_ARG2 BPF_REG_2
66#define BPF_REG_ARG3 BPF_REG_3
67#define BPF_REG_ARG4 BPF_REG_4
68#define BPF_REG_ARG5 BPF_REG_5
69#define BPF_REG_CTX BPF_REG_6
70#define BPF_REG_FP BPF_REG_10
71
72/* Additional register mappings for converted user programs. */
73#define BPF_REG_A BPF_REG_0
74#define BPF_REG_X BPF_REG_7
75#define BPF_REG_TMP BPF_REG_8
76
77/* BPF program can access up to 512 bytes of stack space. */
78#define MAX_BPF_STACK 512
79
80/* Helper macros for filter block array initializers. */
81
82/* ALU ops on registers, bpf_add|sub|...: dst_reg += src_reg */
83
84#define BPF_ALU64_REG(OP, DST, SRC) \
85 ((struct bpf_insn) { \
86 .code = BPF_ALU64 | BPF_OP(OP) | BPF_X, \
87 .dst_reg = DST, \
88 .src_reg = SRC, \
89 .off = 0, \
90 .imm = 0 })
91
92#define BPF_ALU32_REG(OP, DST, SRC) \
93 ((struct bpf_insn) { \
94 .code = BPF_ALU | BPF_OP(OP) | BPF_X, \
95 .dst_reg = DST, \
96 .src_reg = SRC, \
97 .off = 0, \
98 .imm = 0 })
99
100/* ALU ops on immediates, bpf_add|sub|...: dst_reg += imm32 */
101
102#define BPF_ALU64_IMM(OP, DST, IMM) \
103 ((struct bpf_insn) { \
104 .code = BPF_ALU64 | BPF_OP(OP) | BPF_K, \
105 .dst_reg = DST, \
106 .src_reg = 0, \
107 .off = 0, \
108 .imm = IMM })
109
110#define BPF_ALU32_IMM(OP, DST, IMM) \
111 ((struct bpf_insn) { \
112 .code = BPF_ALU | BPF_OP(OP) | BPF_K, \
113 .dst_reg = DST, \
114 .src_reg = 0, \
115 .off = 0, \
116 .imm = IMM })
117
118/* Endianess conversion, cpu_to_{l,b}e(), {l,b}e_to_cpu() */
119
120#define BPF_ENDIAN(TYPE, DST, LEN) \
121 ((struct bpf_insn) { \
122 .code = BPF_ALU | BPF_END | BPF_SRC(TYPE), \
123 .dst_reg = DST, \
124 .src_reg = 0, \
125 .off = 0, \
126 .imm = LEN })
127
128/* Short form of mov, dst_reg = src_reg */
129
130#define BPF_MOV64_REG(DST, SRC) \
131 ((struct bpf_insn) { \
132 .code = BPF_ALU64 | BPF_MOV | BPF_X, \
133 .dst_reg = DST, \
134 .src_reg = SRC, \
135 .off = 0, \
136 .imm = 0 })
137
138#define BPF_MOV32_REG(DST, SRC) \
139 ((struct bpf_insn) { \
140 .code = BPF_ALU | BPF_MOV | BPF_X, \
141 .dst_reg = DST, \
142 .src_reg = SRC, \
143 .off = 0, \
144 .imm = 0 })
145
146/* Short form of mov, dst_reg = imm32 */
147
148#define BPF_MOV64_IMM(DST, IMM) \
149 ((struct bpf_insn) { \
150 .code = BPF_ALU64 | BPF_MOV | BPF_K, \
151 .dst_reg = DST, \
152 .src_reg = 0, \
153 .off = 0, \
154 .imm = IMM })
155
156#define BPF_MOV32_IMM(DST, IMM) \
157 ((struct bpf_insn) { \
158 .code = BPF_ALU | BPF_MOV | BPF_K, \
159 .dst_reg = DST, \
160 .src_reg = 0, \
161 .off = 0, \
162 .imm = IMM })
163
164/* Short form of mov based on type, BPF_X: dst_reg = src_reg, BPF_K: dst_reg = imm32 */
165
166#define BPF_MOV64_RAW(TYPE, DST, SRC, IMM) \
167 ((struct bpf_insn) { \
168 .code = BPF_ALU64 | BPF_MOV | BPF_SRC(TYPE), \
169 .dst_reg = DST, \
170 .src_reg = SRC, \
171 .off = 0, \
172 .imm = IMM })
173
174#define BPF_MOV32_RAW(TYPE, DST, SRC, IMM) \
175 ((struct bpf_insn) { \
176 .code = BPF_ALU | BPF_MOV | BPF_SRC(TYPE), \
177 .dst_reg = DST, \
178 .src_reg = SRC, \
179 .off = 0, \
180 .imm = IMM })
181
182/* Direct packet access, R0 = *(uint *) (skb->data + imm32) */
183
184#define BPF_LD_ABS(SIZE, IMM) \
185 ((struct bpf_insn) { \
186 .code = BPF_LD | BPF_SIZE(SIZE) | BPF_ABS, \
187 .dst_reg = 0, \
188 .src_reg = 0, \
189 .off = 0, \
190 .imm = IMM })
191
192/* Indirect packet access, R0 = *(uint *) (skb->data + src_reg + imm32) */
193
194#define BPF_LD_IND(SIZE, SRC, IMM) \
195 ((struct bpf_insn) { \
196 .code = BPF_LD | BPF_SIZE(SIZE) | BPF_IND, \
197 .dst_reg = 0, \
198 .src_reg = SRC, \
199 .off = 0, \
200 .imm = IMM })
201
202/* Memory load, dst_reg = *(uint *) (src_reg + off16) */
203
204#define BPF_LDX_MEM(SIZE, DST, SRC, OFF) \
205 ((struct bpf_insn) { \
206 .code = BPF_LDX | BPF_SIZE(SIZE) | BPF_MEM, \
207 .dst_reg = DST, \
208 .src_reg = SRC, \
209 .off = OFF, \
210 .imm = 0 })
211
212/* Memory store, *(uint *) (dst_reg + off16) = src_reg */
213
214#define BPF_STX_MEM(SIZE, DST, SRC, OFF) \
215 ((struct bpf_insn) { \
216 .code = BPF_STX | BPF_SIZE(SIZE) | BPF_MEM, \
217 .dst_reg = DST, \
218 .src_reg = SRC, \
219 .off = OFF, \
220 .imm = 0 })
221
222/* Memory store, *(uint *) (dst_reg + off16) = imm32 */
223
224#define BPF_ST_MEM(SIZE, DST, OFF, IMM) \
225 ((struct bpf_insn) { \
226 .code = BPF_ST | BPF_SIZE(SIZE) | BPF_MEM, \
227 .dst_reg = DST, \
228 .src_reg = 0, \
229 .off = OFF, \
230 .imm = IMM })
231
232/* Conditional jumps against registers, if (dst_reg 'op' src_reg) goto pc + off16 */
233
234#define BPF_JMP_REG(OP, DST, SRC, OFF) \
235 ((struct bpf_insn) { \
236 .code = BPF_JMP | BPF_OP(OP) | BPF_X, \
237 .dst_reg = DST, \
238 .src_reg = SRC, \
239 .off = OFF, \
240 .imm = 0 })
241
242/* Conditional jumps against immediates, if (dst_reg 'op' imm32) goto pc + off16 */
243
244#define BPF_JMP_IMM(OP, DST, IMM, OFF) \
245 ((struct bpf_insn) { \
246 .code = BPF_JMP | BPF_OP(OP) | BPF_K, \
247 .dst_reg = DST, \
248 .src_reg = 0, \
249 .off = OFF, \
250 .imm = IMM })
251
252/* Function call */
253
254#define BPF_EMIT_CALL(FUNC) \
255 ((struct bpf_insn) { \
256 .code = BPF_JMP | BPF_CALL, \
257 .dst_reg = 0, \
258 .src_reg = 0, \
259 .off = 0, \
260 .imm = ((FUNC) - __bpf_call_base) })
261
262/* Raw code statement block */
263
264#define BPF_RAW_INSN(CODE, DST, SRC, OFF, IMM) \
265 ((struct bpf_insn) { \
266 .code = CODE, \
267 .dst_reg = DST, \
268 .src_reg = SRC, \
269 .off = OFF, \
270 .imm = IMM })
271
272/* Program exit */
273
274#define BPF_EXIT_INSN() \
275 ((struct bpf_insn) { \
276 .code = BPF_JMP | BPF_EXIT, \
277 .dst_reg = 0, \
278 .src_reg = 0, \
279 .off = 0, \
280 .imm = 0 })
281
282#define bytes_to_bpf_size(bytes) \
283({ \
284 int bpf_size = -EINVAL; \
285 \
286 if (bytes == sizeof(u8)) \
287 bpf_size = BPF_B; \
288 else if (bytes == sizeof(u16)) \
289 bpf_size = BPF_H; \
290 else if (bytes == sizeof(u32)) \
291 bpf_size = BPF_W; \
292 else if (bytes == sizeof(u64)) \
293 bpf_size = BPF_DW; \
294 \
295 bpf_size; \
296})
297
298/* Macro to invoke filter function. */
299#define SK_RUN_FILTER(filter, ctx) \
300 (*filter->prog->bpf_func)(ctx, filter->prog->insnsi)
301
302struct bpf_insn {
303 __u8 code; /* opcode */
304 __u8 dst_reg:4; /* dest register */
305 __u8 src_reg:4; /* source register */
306 __s16 off; /* signed offset */
307 __s32 imm; /* signed immediate constant */
308};
309
310#ifdef CONFIG_COMPAT
311/* A struct sock_filter is architecture independent. */
312struct compat_sock_fprog {
313 u16 len;
314 compat_uptr_t filter; /* struct sock_filter * */
315};
316#endif
317
318struct sock_fprog_kern {
319 u16 len;
320 struct sock_filter *filter;
321};
322
323struct sk_buff;
324struct sock;
325struct seccomp_data;
326
327struct bpf_prog {
328 u32 jited:1, /* Is our filter JIT'ed? */
329 len:31; /* Number of filter blocks */
330 struct sock_fprog_kern *orig_prog; /* Original BPF program */
331 unsigned int (*bpf_func)(const struct sk_buff *skb,
332 const struct bpf_insn *filter);
333 union {
334 struct sock_filter insns[0];
335 struct bpf_insn insnsi[0];
336 struct work_struct work;
337 };
338};
339
340struct sk_filter {
341 atomic_t refcnt;
342 struct rcu_head rcu;
343 struct bpf_prog *prog;
344};
345
346#define BPF_PROG_RUN(filter, ctx) (*filter->bpf_func)(ctx, filter->insnsi)
347
348static inline unsigned int bpf_prog_size(unsigned int proglen)
349{
350 return max(sizeof(struct bpf_prog),
351 offsetof(struct bpf_prog, insns[proglen]));
352}
353
354#define bpf_classic_proglen(fprog) (fprog->len * sizeof(fprog->filter[0]))
355
356int sk_filter(struct sock *sk, struct sk_buff *skb);
357
358void bpf_prog_select_runtime(struct bpf_prog *fp);
359void bpf_prog_free(struct bpf_prog *fp);
360
361int bpf_convert_filter(struct sock_filter *prog, int len,
362 struct bpf_insn *new_prog, int *new_len);
363
364int bpf_prog_create(struct bpf_prog **pfp, struct sock_fprog_kern *fprog);
365void bpf_prog_destroy(struct bpf_prog *fp);
366
367int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk);
368int sk_detach_filter(struct sock *sk);
369
370int bpf_check_classic(const struct sock_filter *filter, unsigned int flen);
371int sk_get_filter(struct sock *sk, struct sock_filter __user *filter,
372 unsigned int len);
373
374bool sk_filter_charge(struct sock *sk, struct sk_filter *fp);
375void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp);
376
377u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
378void bpf_int_jit_compile(struct bpf_prog *fp);
379
380#define BPF_ANC BIT(15)
381
382static inline u16 bpf_anc_helper(const struct sock_filter *ftest)
383{
384 BUG_ON(ftest->code & BPF_ANC);
385
386 switch (ftest->code) {
387 case BPF_LD | BPF_W | BPF_ABS:
388 case BPF_LD | BPF_H | BPF_ABS:
389 case BPF_LD | BPF_B | BPF_ABS:
390#define BPF_ANCILLARY(CODE) case SKF_AD_OFF + SKF_AD_##CODE: \
391 return BPF_ANC | SKF_AD_##CODE
392 switch (ftest->k) {
393 BPF_ANCILLARY(PROTOCOL);
394 BPF_ANCILLARY(PKTTYPE);
395 BPF_ANCILLARY(IFINDEX);
396 BPF_ANCILLARY(NLATTR);
397 BPF_ANCILLARY(NLATTR_NEST);
398 BPF_ANCILLARY(MARK);
399 BPF_ANCILLARY(QUEUE);
400 BPF_ANCILLARY(HATYPE);
401 BPF_ANCILLARY(RXHASH);
402 BPF_ANCILLARY(CPU);
403 BPF_ANCILLARY(ALU_XOR_X);
404 BPF_ANCILLARY(VLAN_TAG);
405 BPF_ANCILLARY(VLAN_TAG_PRESENT);
406 BPF_ANCILLARY(PAY_OFFSET);
407 BPF_ANCILLARY(RANDOM);
408 }
409 /* Fallthrough. */
410 default:
411 return ftest->code;
412 }
413}
414
415void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb,
416 int k, unsigned int size);
417
418static inline void *bpf_load_pointer(const struct sk_buff *skb, int k,
419 unsigned int size, void *buffer)
420{
421 if (k >= 0)
422 return skb_header_pointer(skb, k, size, buffer);
423
424 return bpf_internal_load_pointer_neg_helper(skb, k, size);
425}
426
427#ifdef CONFIG_BPF_JIT
428#include <stdarg.h>
429#include <linux/linkage.h>
430#include <linux/printk.h>
431
432void bpf_jit_compile(struct bpf_prog *fp);
433void bpf_jit_free(struct bpf_prog *fp);
434
435static inline void bpf_jit_dump(unsigned int flen, unsigned int proglen,
436 u32 pass, void *image)
437{
438 pr_err("flen=%u proglen=%u pass=%u image=%pK\n",
439 flen, proglen, pass, image);
440 if (image)
441 print_hex_dump(KERN_ERR, "JIT code: ", DUMP_PREFIX_OFFSET,
442 16, 1, image, proglen, false);
443}
444#else
445#include <linux/slab.h>
446
447static inline void bpf_jit_compile(struct bpf_prog *fp)
448{
449}
450
451static inline void bpf_jit_free(struct bpf_prog *fp)
452{
453 kfree(fp);
454}
455#endif /* CONFIG_BPF_JIT */
456
457static inline int bpf_tell_extensions(void)
458{
459 return SKF_AD_MAX;
460}
461
462#endif /* __LINUX_FILTER_H__ */