2 * Linux Socket Filter Data Structures
4 #ifndef __LINUX_FILTER_H__
5 #define __LINUX_FILTER_H__
7 #include <linux/atomic.h>
8 #include <linux/compat.h>
9 #include <linux/workqueue.h>
10 #include <uapi/linux/filter.h>
12 /* Internally used and optimized filter representation with extended
13 * instruction set based on top of classic BPF.
16 /* instruction classes */
17 #define BPF_ALU64 0x07 /* alu mode in double word width */
20 #define BPF_DW 0x18 /* double word */
21 #define BPF_XADD 0xc0 /* exclusive add */
24 #define BPF_MOV 0xb0 /* mov reg to reg */
25 #define BPF_ARSH 0xc0 /* sign extending arithmetic shift right */
27 /* change endianness of a register */
28 #define BPF_END 0xd0 /* flags for endianness conversion: */
29 #define BPF_TO_LE 0x00 /* convert to little-endian */
30 #define BPF_TO_BE 0x08 /* convert to big-endian */
31 #define BPF_FROM_LE BPF_TO_LE
32 #define BPF_FROM_BE BPF_TO_BE
34 #define BPF_JNE 0x50 /* jump != */
35 #define BPF_JSGT 0x60 /* SGT is signed '>', GT in x86 */
36 #define BPF_JSGE 0x70 /* SGE is signed '>=', GE in x86 */
37 #define BPF_CALL 0x80 /* function call */
38 #define BPF_EXIT 0x90 /* function return */
40 /* Register numbers */
56 /* BPF has 10 general purpose 64-bit registers and stack frame. */
57 #define MAX_BPF_REG __MAX_BPF_REG
59 /* ArgX, context and stack frame pointer register positions. Note,
60 * Arg1, Arg2, Arg3, etc are used as argument mappings of function
61 * calls in BPF_CALL instruction.
63 #define BPF_REG_ARG1 BPF_REG_1
64 #define BPF_REG_ARG2 BPF_REG_2
65 #define BPF_REG_ARG3 BPF_REG_3
66 #define BPF_REG_ARG4 BPF_REG_4
67 #define BPF_REG_ARG5 BPF_REG_5
68 #define BPF_REG_CTX BPF_REG_6
69 #define BPF_REG_FP BPF_REG_10
71 /* Additional register mappings for converted user programs. */
72 #define BPF_REG_A BPF_REG_0
73 #define BPF_REG_X BPF_REG_7
74 #define BPF_REG_TMP BPF_REG_8
76 /* BPF program can access up to 512 bytes of stack space. */
77 #define MAX_BPF_STACK 512
79 /* Helper macros for filter block array initializers. */
81 /* ALU ops on registers, bpf_add|sub|...: dst_reg += src_reg */
83 #define BPF_ALU64_REG(OP, DST, SRC) \
84 ((struct sock_filter_int) { \
85 .code = BPF_ALU64 | BPF_OP(OP) | BPF_X, \
91 #define BPF_ALU32_REG(OP, DST, SRC) \
92 ((struct sock_filter_int) { \
93 .code = BPF_ALU | BPF_OP(OP) | BPF_X, \
99 /* ALU ops on immediates, bpf_add|sub|...: dst_reg += imm32 */
101 #define BPF_ALU64_IMM(OP, DST, IMM) \
102 ((struct sock_filter_int) { \
103 .code = BPF_ALU64 | BPF_OP(OP) | BPF_K, \
109 #define BPF_ALU32_IMM(OP, DST, IMM) \
110 ((struct sock_filter_int) { \
111 .code = BPF_ALU | BPF_OP(OP) | BPF_K, \
117 /* Endianess conversion, cpu_to_{l,b}e(), {l,b}e_to_cpu() */
119 #define BPF_ENDIAN(TYPE, DST, LEN) \
120 ((struct sock_filter_int) { \
121 .code = BPF_ALU | BPF_END | BPF_SRC(TYPE), \
127 /* Short form of mov, dst_reg = src_reg */
129 #define BPF_MOV64_REG(DST, SRC) \
130 ((struct sock_filter_int) { \
131 .code = BPF_ALU64 | BPF_MOV | BPF_X, \
137 #define BPF_MOV32_REG(DST, SRC) \
138 ((struct sock_filter_int) { \
139 .code = BPF_ALU | BPF_MOV | BPF_X, \
145 /* Short form of mov, dst_reg = imm32 */
147 #define BPF_MOV64_IMM(DST, IMM) \
148 ((struct sock_filter_int) { \
149 .code = BPF_ALU64 | BPF_MOV | BPF_K, \
155 #define BPF_MOV32_IMM(DST, IMM) \
156 ((struct sock_filter_int) { \
157 .code = BPF_ALU | BPF_MOV | BPF_K, \
163 /* Short form of mov based on type, BPF_X: dst_reg = src_reg, BPF_K: dst_reg = imm32 */
165 #define BPF_MOV64_RAW(TYPE, DST, SRC, IMM) \
166 ((struct sock_filter_int) { \
167 .code = BPF_ALU64 | BPF_MOV | BPF_SRC(TYPE), \
173 #define BPF_MOV32_RAW(TYPE, DST, SRC, IMM) \
174 ((struct sock_filter_int) { \
175 .code = BPF_ALU | BPF_MOV | BPF_SRC(TYPE), \
181 /* Direct packet access, R0 = *(uint *) (skb->data + imm32) */
183 #define BPF_LD_ABS(SIZE, IMM) \
184 ((struct sock_filter_int) { \
185 .code = BPF_LD | BPF_SIZE(SIZE) | BPF_ABS, \
191 /* Indirect packet access, R0 = *(uint *) (skb->data + src_reg + imm32) */
193 #define BPF_LD_IND(SIZE, SRC, IMM) \
194 ((struct sock_filter_int) { \
195 .code = BPF_LD | BPF_SIZE(SIZE) | BPF_IND, \
201 /* Memory load, dst_reg = *(uint *) (src_reg + off16) */
203 #define BPF_LDX_MEM(SIZE, DST, SRC, OFF) \
204 ((struct sock_filter_int) { \
205 .code = BPF_LDX | BPF_SIZE(SIZE) | BPF_MEM, \
211 /* Memory store, *(uint *) (dst_reg + off16) = src_reg */
213 #define BPF_STX_MEM(SIZE, DST, SRC, OFF) \
214 ((struct sock_filter_int) { \
215 .code = BPF_STX | BPF_SIZE(SIZE) | BPF_MEM, \
221 /* Memory store, *(uint *) (dst_reg + off16) = imm32 */
223 #define BPF_ST_MEM(SIZE, DST, OFF, IMM) \
224 ((struct sock_filter_int) { \
225 .code = BPF_ST | BPF_SIZE(SIZE) | BPF_MEM, \
231 /* Conditional jumps against registers, if (dst_reg 'op' src_reg) goto pc + off16 */
233 #define BPF_JMP_REG(OP, DST, SRC, OFF) \
234 ((struct sock_filter_int) { \
235 .code = BPF_JMP | BPF_OP(OP) | BPF_X, \
241 /* Conditional jumps against immediates, if (dst_reg 'op' imm32) goto pc + off16 */
243 #define BPF_JMP_IMM(OP, DST, IMM, OFF) \
244 ((struct sock_filter_int) { \
245 .code = BPF_JMP | BPF_OP(OP) | BPF_K, \
253 #define BPF_EMIT_CALL(FUNC) \
254 ((struct sock_filter_int) { \
255 .code = BPF_JMP | BPF_CALL, \
259 .imm = ((FUNC) - __bpf_call_base) })
261 /* Raw code statement block */
263 #define BPF_RAW_INSN(CODE, DST, SRC, OFF, IMM) \
264 ((struct sock_filter_int) { \
273 #define BPF_EXIT_INSN() \
274 ((struct sock_filter_int) { \
275 .code = BPF_JMP | BPF_EXIT, \
281 #define bytes_to_bpf_size(bytes) \
283 int bpf_size = -EINVAL; \
285 if (bytes == sizeof(u8)) \
287 else if (bytes == sizeof(u16)) \
289 else if (bytes == sizeof(u32)) \
291 else if (bytes == sizeof(u64)) \
297 /* Macro to invoke filter function. */
298 #define SK_RUN_FILTER(filter, ctx) (*filter->bpf_func)(ctx, filter->insnsi)
300 struct sock_filter_int {
301 __u8 code; /* opcode */
302 __u8 dst_reg:4; /* dest register */
303 __u8 src_reg:4; /* source register */
304 __s16 off; /* signed offset */
305 __s32 imm; /* signed immediate constant */
309 /* A struct sock_filter is architecture independent. */
310 struct compat_sock_fprog {
312 compat_uptr_t filter; /* struct sock_filter * */
316 struct sock_fprog_kern {
318 struct sock_filter *filter;
327 u32 jited:1, /* Is our filter JIT'ed? */
328 len:31; /* Number of filter blocks */
329 struct sock_fprog_kern *orig_prog; /* Original BPF program */
331 unsigned int (*bpf_func)(const struct sk_buff *skb,
332 const struct sock_filter_int *filter);
334 struct sock_filter insns[0];
335 struct sock_filter_int insnsi[0];
336 struct work_struct work;
340 static inline unsigned int sk_filter_size(unsigned int proglen)
342 return max(sizeof(struct sk_filter),
343 offsetof(struct sk_filter, insns[proglen]));
346 #define sk_filter_proglen(fprog) \
347 (fprog->len * sizeof(fprog->filter[0]))
349 int sk_filter_trim_cap(struct sock *sk, struct sk_buff *skb, unsigned int cap);
350 static inline int sk_filter(struct sock *sk, struct sk_buff *skb)
352 return sk_filter_trim_cap(sk, skb, 1);
355 void sk_filter_select_runtime(struct sk_filter *fp);
356 void sk_filter_free(struct sk_filter *fp);
358 int sk_convert_filter(struct sock_filter *prog, int len,
359 struct sock_filter_int *new_prog, int *new_len);
361 int sk_unattached_filter_create(struct sk_filter **pfp,
362 struct sock_fprog_kern *fprog);
363 void sk_unattached_filter_destroy(struct sk_filter *fp);
365 int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk);
366 int __sk_attach_filter(struct sock_fprog *fprog, struct sock *sk,
368 int sk_detach_filter(struct sock *sk);
369 int __sk_detach_filter(struct sock *sk, bool locked);
371 int sk_chk_filter(struct sock_filter *filter, unsigned int flen);
372 int sk_get_filter(struct sock *sk, struct sock_filter __user *filter,
375 void sk_filter_charge(struct sock *sk, struct sk_filter *fp);
376 void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp);
378 u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5);
379 void bpf_int_jit_compile(struct sk_filter *fp);
381 #define BPF_ANC BIT(15)
383 static inline bool bpf_needs_clear_a(const struct sock_filter *first)
385 switch (first->code) {
386 case BPF_RET | BPF_K:
387 case BPF_LD | BPF_W | BPF_LEN:
390 case BPF_LD | BPF_W | BPF_ABS:
391 case BPF_LD | BPF_H | BPF_ABS:
392 case BPF_LD | BPF_B | BPF_ABS:
393 if (first->k == SKF_AD_OFF + SKF_AD_ALU_XOR_X)
402 static inline u16 bpf_anc_helper(const struct sock_filter *ftest)
404 BUG_ON(ftest->code & BPF_ANC);
406 switch (ftest->code) {
407 case BPF_LD | BPF_W | BPF_ABS:
408 case BPF_LD | BPF_H | BPF_ABS:
409 case BPF_LD | BPF_B | BPF_ABS:
410 #define BPF_ANCILLARY(CODE) case SKF_AD_OFF + SKF_AD_##CODE: \
411 return BPF_ANC | SKF_AD_##CODE
413 BPF_ANCILLARY(PROTOCOL);
414 BPF_ANCILLARY(PKTTYPE);
415 BPF_ANCILLARY(IFINDEX);
416 BPF_ANCILLARY(NLATTR);
417 BPF_ANCILLARY(NLATTR_NEST);
419 BPF_ANCILLARY(QUEUE);
420 BPF_ANCILLARY(HATYPE);
421 BPF_ANCILLARY(RXHASH);
423 BPF_ANCILLARY(ALU_XOR_X);
424 BPF_ANCILLARY(VLAN_TAG);
425 BPF_ANCILLARY(VLAN_TAG_PRESENT);
426 BPF_ANCILLARY(PAY_OFFSET);
427 BPF_ANCILLARY(RANDOM);
435 #ifdef CONFIG_BPF_JIT
437 #include <linux/linkage.h>
438 #include <linux/printk.h>
440 void bpf_jit_compile(struct sk_filter *fp);
441 void bpf_jit_free(struct sk_filter *fp);
443 static inline void bpf_jit_dump(unsigned int flen, unsigned int proglen,
444 u32 pass, void *image)
446 pr_err("flen=%u proglen=%u pass=%u image=%pK\n",
447 flen, proglen, pass, image);
449 print_hex_dump(KERN_ERR, "JIT code: ", DUMP_PREFIX_OFFSET,
450 16, 1, image, proglen, false);
453 #include <linux/slab.h>
455 static inline void bpf_jit_compile(struct sk_filter *fp)
459 static inline void bpf_jit_free(struct sk_filter *fp)
463 #endif /* CONFIG_BPF_JIT */
465 static inline int bpf_tell_extensions(void)
470 #endif /* __LINUX_FILTER_H__ */