diff options
Diffstat (limited to 'include/linux/filter.h')
| -rw-r--r-- | include/linux/filter.h | 235 |
1 files changed, 235 insertions, 0 deletions
diff --git a/include/linux/filter.h b/include/linux/filter.h new file mode 100644 index 00000000..9ee3f9fb --- /dev/null +++ b/include/linux/filter.h @@ -0,0 +1,235 @@ +/* + * Linux Socket Filter Data Structures + */ + +#ifndef __LINUX_FILTER_H__ +#define __LINUX_FILTER_H__ + +#include <linux/compiler.h> +#include <linux/types.h> + +#ifdef __KERNEL__ +#include <asm/atomic.h> +#endif + +/* + * Current version of the filter code architecture. + */ +#define BPF_MAJOR_VERSION 1 +#define BPF_MINOR_VERSION 1 + +/* + * Try and keep these values and structures similar to BSD, especially + * the BPF code definitions which need to match so you can share filters + */ + +struct sock_filter { /* Filter block */ + __u16 code; /* Actual filter code */ + __u8 jt; /* Jump true */ + __u8 jf; /* Jump false */ + __u32 k; /* Generic multiuse field */ +}; + +struct sock_fprog { /* Required for SO_ATTACH_FILTER. */ + unsigned short len; /* Number of filter blocks */ + struct sock_filter __user *filter; +}; + +/* + * Instruction classes + */ + +#define BPF_CLASS(code) ((code) & 0x07) +#define BPF_LD 0x00 +#define BPF_LDX 0x01 +#define BPF_ST 0x02 +#define BPF_STX 0x03 +#define BPF_ALU 0x04 +#define BPF_JMP 0x05 +#define BPF_RET 0x06 +#define BPF_MISC 0x07 + +/* ld/ldx fields */ +#define BPF_SIZE(code) ((code) & 0x18) +#define BPF_W 0x00 +#define BPF_H 0x08 +#define BPF_B 0x10 +#define BPF_MODE(code) ((code) & 0xe0) +#define BPF_IMM 0x00 +#define BPF_ABS 0x20 +#define BPF_IND 0x40 +#define BPF_MEM 0x60 +#define BPF_LEN 0x80 +#define BPF_MSH 0xa0 + +/* alu/jmp fields */ +#define BPF_OP(code) ((code) & 0xf0) +#define BPF_ADD 0x00 +#define BPF_SUB 0x10 +#define BPF_MUL 0x20 +#define BPF_DIV 0x30 +#define BPF_OR 0x40 +#define BPF_AND 0x50 +#define BPF_LSH 0x60 +#define BPF_RSH 0x70 +#define BPF_NEG 0x80 +#define BPF_JA 0x00 +#define BPF_JEQ 0x10 +#define BPF_JGT 0x20 +#define BPF_JGE 0x30 +#define BPF_JSET 0x40 +#define BPF_SRC(code) ((code) & 0x08) +#define BPF_K 0x00 +#define BPF_X 0x08 + +/* ret - BPF_K and BPF_X also apply */ +#define BPF_RVAL(code) ((code) & 0x18) +#define BPF_A 0x10 + +/* misc */ +#define BPF_MISCOP(code) ((code) & 0xf8) +#define BPF_TAX 0x00 +#define BPF_TXA 0x80 + +#ifndef BPF_MAXINSNS +#define BPF_MAXINSNS 4096 +#endif + +/* + * Macros for filter block array initializers. + */ +#ifndef BPF_STMT +#define BPF_STMT(code, k) { (unsigned short)(code), 0, 0, k } +#endif +#ifndef BPF_JUMP +#define BPF_JUMP(code, k, jt, jf) { (unsigned short)(code), jt, jf, k } +#endif + +/* + * Number of scratch memory words for: BPF_ST and BPF_STX + */ +#define BPF_MEMWORDS 16 + +/* RATIONALE. Negative offsets are invalid in BPF. + We use them to reference ancillary data. + Unlike introduction new instructions, it does not break + existing compilers/optimizers. + */ +#define SKF_AD_OFF (-0x1000) +#define SKF_AD_PROTOCOL 0 +#define SKF_AD_PKTTYPE 4 +#define SKF_AD_IFINDEX 8 +#define SKF_AD_NLATTR 12 +#define SKF_AD_NLATTR_NEST 16 +#define SKF_AD_MARK 20 +#define SKF_AD_QUEUE 24 +#define SKF_AD_HATYPE 28 +#define SKF_AD_RXHASH 32 +#define SKF_AD_CPU 36 +#define SKF_AD_MAX 40 +#define SKF_NET_OFF (-0x100000) +#define SKF_LL_OFF (-0x200000) + +#ifdef __KERNEL__ + +struct sk_buff; +struct sock; + +struct sk_filter +{ + atomic_t refcnt; + unsigned int len; /* Number of filter blocks */ + unsigned int (*bpf_func)(const struct sk_buff *skb, + const struct sock_filter *filter); + struct rcu_head rcu; + struct sock_filter insns[0]; +}; + +static inline unsigned int sk_filter_len(const struct sk_filter *fp) +{ + return fp->len * sizeof(struct sock_filter) + sizeof(*fp); +} + +extern int sk_filter(struct sock *sk, struct sk_buff *skb); +extern unsigned int sk_run_filter(const struct sk_buff *skb, + const struct sock_filter *filter); +extern int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk); +extern int sk_detach_filter(struct sock *sk); +extern int sk_chk_filter(struct sock_filter *filter, int flen); + +#ifdef CONFIG_BPF_JIT +extern void bpf_jit_compile(struct sk_filter *fp); +extern void bpf_jit_free(struct sk_filter *fp); +#define SK_RUN_FILTER(FILTER, SKB) (*FILTER->bpf_func)(SKB, FILTER->insns) +#else +static inline void bpf_jit_compile(struct sk_filter *fp) +{ +} +static inline void bpf_jit_free(struct sk_filter *fp) +{ +} +#define SK_RUN_FILTER(FILTER, SKB) sk_run_filter(SKB, FILTER->insns) +#endif + +enum { + BPF_S_RET_K = 1, + BPF_S_RET_A, + BPF_S_ALU_ADD_K, + BPF_S_ALU_ADD_X, + BPF_S_ALU_SUB_K, + BPF_S_ALU_SUB_X, + BPF_S_ALU_MUL_K, + BPF_S_ALU_MUL_X, + BPF_S_ALU_DIV_X, + BPF_S_ALU_AND_K, + BPF_S_ALU_AND_X, + BPF_S_ALU_OR_K, + BPF_S_ALU_OR_X, + BPF_S_ALU_LSH_K, + BPF_S_ALU_LSH_X, + BPF_S_ALU_RSH_K, + BPF_S_ALU_RSH_X, + BPF_S_ALU_NEG, + BPF_S_LD_W_ABS, + BPF_S_LD_H_ABS, + BPF_S_LD_B_ABS, + BPF_S_LD_W_LEN, + BPF_S_LD_W_IND, + BPF_S_LD_H_IND, + BPF_S_LD_B_IND, + BPF_S_LD_IMM, + BPF_S_LDX_W_LEN, + BPF_S_LDX_B_MSH, + BPF_S_LDX_IMM, + BPF_S_MISC_TAX, + BPF_S_MISC_TXA, + BPF_S_ALU_DIV_K, + BPF_S_LD_MEM, + BPF_S_LDX_MEM, + BPF_S_ST, + BPF_S_STX, + BPF_S_JMP_JA, + BPF_S_JMP_JEQ_K, + BPF_S_JMP_JEQ_X, + BPF_S_JMP_JGE_K, + BPF_S_JMP_JGE_X, + BPF_S_JMP_JGT_K, + BPF_S_JMP_JGT_X, + BPF_S_JMP_JSET_K, + BPF_S_JMP_JSET_X, + /* Ancillary data */ + BPF_S_ANC_PROTOCOL, + BPF_S_ANC_PKTTYPE, + BPF_S_ANC_IFINDEX, + BPF_S_ANC_NLATTR, + BPF_S_ANC_NLATTR_NEST, + BPF_S_ANC_MARK, + BPF_S_ANC_QUEUE, + BPF_S_ANC_HATYPE, + BPF_S_ANC_RXHASH, + BPF_S_ANC_CPU, +}; + +#endif /* __KERNEL__ */ + +#endif /* __LINUX_FILTER_H__ */ |