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| Rev | Author | Line No. | Line |
|---|---|---|---|
| 422 | giacomo | 1 | /* |
| 2 | * Linux Socket Filter Data Structures |
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| 3 | */ |
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| 4 | |||
| 5 | #ifndef __LINUX_FILTER_H__ |
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| 6 | #define __LINUX_FILTER_H__ |
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| 7 | |||
| 8 | /* |
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| 9 | * Current version of the filter code architecture. |
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| 10 | */ |
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| 11 | #define BPF_MAJOR_VERSION 1 |
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| 12 | #define BPF_MINOR_VERSION 1 |
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| 13 | |||
| 14 | /* |
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| 15 | * Try and keep these values and structures similar to BSD, especially |
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| 16 | * the BPF code definitions which need to match so you can share filters |
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| 17 | */ |
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| 18 | |||
| 19 | struct sock_filter /* Filter block */ |
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| 20 | { |
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| 21 | __u16 code; /* Actual filter code */ |
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| 22 | __u8 jt; /* Jump true */ |
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| 23 | __u8 jf; /* Jump false */ |
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| 24 | __u32 k; /* Generic multiuse field */ |
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| 25 | }; |
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| 26 | |||
| 27 | struct sock_fprog /* Required for SO_ATTACH_FILTER. */ |
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| 28 | { |
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| 29 | unsigned short len; /* Number of filter blocks */ |
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| 30 | struct sock_filter *filter; |
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| 31 | }; |
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| 32 | |||
| 33 | #ifdef __KERNEL__ |
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| 34 | struct sk_filter |
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| 35 | { |
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| 36 | atomic_t refcnt; |
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| 37 | unsigned int len; /* Number of filter blocks */ |
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| 38 | struct sock_filter insns[0]; |
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| 39 | }; |
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| 40 | |||
| 41 | static inline unsigned int sk_filter_len(struct sk_filter *fp) |
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| 42 | { |
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| 43 | return fp->len*sizeof(struct sock_filter) + sizeof(*fp); |
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| 44 | } |
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| 45 | #endif |
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| 46 | |||
| 47 | /* |
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| 48 | * Instruction classes |
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| 49 | */ |
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| 50 | |||
| 51 | #define BPF_CLASS(code) ((code) & 0x07) |
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| 52 | #define BPF_LD 0x00 |
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| 53 | #define BPF_LDX 0x01 |
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| 54 | #define BPF_ST 0x02 |
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| 55 | #define BPF_STX 0x03 |
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| 56 | #define BPF_ALU 0x04 |
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| 57 | #define BPF_JMP 0x05 |
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| 58 | #define BPF_RET 0x06 |
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| 59 | #define BPF_MISC 0x07 |
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| 60 | |||
| 61 | /* ld/ldx fields */ |
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| 62 | #define BPF_SIZE(code) ((code) & 0x18) |
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| 63 | #define BPF_W 0x00 |
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| 64 | #define BPF_H 0x08 |
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| 65 | #define BPF_B 0x10 |
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| 66 | #define BPF_MODE(code) ((code) & 0xe0) |
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| 67 | #define BPF_IMM 0x00 |
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| 68 | #define BPF_ABS 0x20 |
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| 69 | #define BPF_IND 0x40 |
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| 70 | #define BPF_MEM 0x60 |
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| 71 | #define BPF_LEN 0x80 |
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| 72 | #define BPF_MSH 0xa0 |
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| 73 | |||
| 74 | /* alu/jmp fields */ |
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| 75 | #define BPF_OP(code) ((code) & 0xf0) |
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| 76 | #define BPF_ADD 0x00 |
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| 77 | #define BPF_SUB 0x10 |
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| 78 | #define BPF_MUL 0x20 |
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| 79 | #define BPF_DIV 0x30 |
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| 80 | #define BPF_OR 0x40 |
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| 81 | #define BPF_AND 0x50 |
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| 82 | #define BPF_LSH 0x60 |
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| 83 | #define BPF_RSH 0x70 |
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| 84 | #define BPF_NEG 0x80 |
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| 85 | #define BPF_JA 0x00 |
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| 86 | #define BPF_JEQ 0x10 |
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| 87 | #define BPF_JGT 0x20 |
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| 88 | #define BPF_JGE 0x30 |
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| 89 | #define BPF_JSET 0x40 |
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| 90 | #define BPF_SRC(code) ((code) & 0x08) |
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| 91 | #define BPF_K 0x00 |
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| 92 | #define BPF_X 0x08 |
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| 93 | |||
| 94 | /* ret - BPF_K and BPF_X also apply */ |
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| 95 | #define BPF_RVAL(code) ((code) & 0x18) |
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| 96 | #define BPF_A 0x10 |
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| 97 | |||
| 98 | /* misc */ |
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| 99 | #define BPF_MISCOP(code) ((code) & 0xf8) |
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| 100 | #define BPF_TAX 0x00 |
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| 101 | #define BPF_TXA 0x80 |
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| 102 | |||
| 103 | #ifndef BPF_MAXINSNS |
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| 104 | #define BPF_MAXINSNS 4096 |
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| 105 | #endif |
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| 106 | |||
| 107 | /* |
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| 108 | * Macros for filter block array initializers. |
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| 109 | */ |
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| 110 | #ifndef BPF_STMT |
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| 111 | #define BPF_STMT(code, k) { (unsigned short)(code), 0, 0, k } |
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| 112 | #endif |
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| 113 | #ifndef BPF_JUMP |
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| 114 | #define BPF_JUMP(code, k, jt, jf) { (unsigned short)(code), jt, jf, k } |
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| 115 | #endif |
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| 116 | |||
| 117 | /* |
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| 118 | * Number of scratch memory words for: BPF_ST and BPF_STX |
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| 119 | */ |
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| 120 | #define BPF_MEMWORDS 16 |
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| 121 | |||
| 122 | /* RATIONALE. Negative offsets are invalid in BPF. |
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| 123 | We use them to reference ancillary data. |
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| 124 | Unlike introduction new instructions, it does not break |
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| 125 | existing compilers/optimizers. |
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| 126 | */ |
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| 127 | #define SKF_AD_OFF (-0x1000) |
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| 128 | #define SKF_AD_PROTOCOL 0 |
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| 129 | #define SKF_AD_PKTTYPE 4 |
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| 130 | #define SKF_AD_IFINDEX 8 |
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| 131 | #define SKF_AD_MAX 12 |
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| 132 | #define SKF_NET_OFF (-0x100000) |
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| 133 | #define SKF_LL_OFF (-0x200000) |
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| 134 | |||
| 135 | #ifdef __KERNEL__ |
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| 136 | extern int sk_run_filter(struct sk_buff *skb, struct sock_filter *filter, int flen); |
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| 137 | extern int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk); |
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| 138 | extern int sk_chk_filter(struct sock_filter *filter, int flen); |
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| 139 | #endif /* __KERNEL__ */ |
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| 140 | |||
| 141 | #endif /* __LINUX_FILTER_H__ */ |