Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Linux Socket Filter Data Structures |
| 3 | */ |
| 4 | |
| 5 | #ifndef __LINUX_FILTER_H__ |
| 6 | #define __LINUX_FILTER_H__ |
| 7 | |
| 8 | #include <linux/compiler.h> |
| 9 | #include <linux/types.h> |
| 10 | |
| 11 | #ifdef __KERNEL__ |
| 12 | #include <asm/atomic.h> |
| 13 | #endif |
| 14 | |
| 15 | /* |
| 16 | * Current version of the filter code architecture. |
| 17 | */ |
| 18 | #define BPF_MAJOR_VERSION 1 |
| 19 | #define BPF_MINOR_VERSION 1 |
| 20 | |
| 21 | /* |
| 22 | * Try and keep these values and structures similar to BSD, especially |
| 23 | * the BPF code definitions which need to match so you can share filters |
| 24 | */ |
| 25 | |
| 26 | struct sock_filter /* Filter block */ |
| 27 | { |
| 28 | __u16 code; /* Actual filter code */ |
| 29 | __u8 jt; /* Jump true */ |
| 30 | __u8 jf; /* Jump false */ |
| 31 | __u32 k; /* Generic multiuse field */ |
| 32 | }; |
| 33 | |
| 34 | struct sock_fprog /* Required for SO_ATTACH_FILTER. */ |
| 35 | { |
| 36 | unsigned short len; /* Number of filter blocks */ |
| 37 | struct sock_filter __user *filter; |
| 38 | }; |
| 39 | |
| 40 | #ifdef __KERNEL__ |
| 41 | struct sk_filter |
| 42 | { |
| 43 | atomic_t refcnt; |
| 44 | unsigned int len; /* Number of filter blocks */ |
| 45 | struct sock_filter insns[0]; |
| 46 | }; |
| 47 | |
| 48 | static inline unsigned int sk_filter_len(struct sk_filter *fp) |
| 49 | { |
| 50 | return fp->len*sizeof(struct sock_filter) + sizeof(*fp); |
| 51 | } |
| 52 | #endif |
| 53 | |
| 54 | /* |
| 55 | * Instruction classes |
| 56 | */ |
| 57 | |
| 58 | #define BPF_CLASS(code) ((code) & 0x07) |
| 59 | #define BPF_LD 0x00 |
| 60 | #define BPF_LDX 0x01 |
| 61 | #define BPF_ST 0x02 |
| 62 | #define BPF_STX 0x03 |
| 63 | #define BPF_ALU 0x04 |
| 64 | #define BPF_JMP 0x05 |
| 65 | #define BPF_RET 0x06 |
| 66 | #define BPF_MISC 0x07 |
| 67 | |
| 68 | /* ld/ldx fields */ |
| 69 | #define BPF_SIZE(code) ((code) & 0x18) |
| 70 | #define BPF_W 0x00 |
| 71 | #define BPF_H 0x08 |
| 72 | #define BPF_B 0x10 |
| 73 | #define BPF_MODE(code) ((code) & 0xe0) |
| 74 | #define BPF_IMM 0x00 |
| 75 | #define BPF_ABS 0x20 |
| 76 | #define BPF_IND 0x40 |
| 77 | #define BPF_MEM 0x60 |
| 78 | #define BPF_LEN 0x80 |
| 79 | #define BPF_MSH 0xa0 |
| 80 | |
| 81 | /* alu/jmp fields */ |
| 82 | #define BPF_OP(code) ((code) & 0xf0) |
| 83 | #define BPF_ADD 0x00 |
| 84 | #define BPF_SUB 0x10 |
| 85 | #define BPF_MUL 0x20 |
| 86 | #define BPF_DIV 0x30 |
| 87 | #define BPF_OR 0x40 |
| 88 | #define BPF_AND 0x50 |
| 89 | #define BPF_LSH 0x60 |
| 90 | #define BPF_RSH 0x70 |
| 91 | #define BPF_NEG 0x80 |
| 92 | #define BPF_JA 0x00 |
| 93 | #define BPF_JEQ 0x10 |
| 94 | #define BPF_JGT 0x20 |
| 95 | #define BPF_JGE 0x30 |
| 96 | #define BPF_JSET 0x40 |
| 97 | #define BPF_SRC(code) ((code) & 0x08) |
| 98 | #define BPF_K 0x00 |
| 99 | #define BPF_X 0x08 |
| 100 | |
| 101 | /* ret - BPF_K and BPF_X also apply */ |
| 102 | #define BPF_RVAL(code) ((code) & 0x18) |
| 103 | #define BPF_A 0x10 |
| 104 | |
| 105 | /* misc */ |
| 106 | #define BPF_MISCOP(code) ((code) & 0xf8) |
| 107 | #define BPF_TAX 0x00 |
| 108 | #define BPF_TXA 0x80 |
| 109 | |
| 110 | #ifndef BPF_MAXINSNS |
| 111 | #define BPF_MAXINSNS 4096 |
| 112 | #endif |
| 113 | |
| 114 | /* |
| 115 | * Macros for filter block array initializers. |
| 116 | */ |
| 117 | #ifndef BPF_STMT |
| 118 | #define BPF_STMT(code, k) { (unsigned short)(code), 0, 0, k } |
| 119 | #endif |
| 120 | #ifndef BPF_JUMP |
| 121 | #define BPF_JUMP(code, k, jt, jf) { (unsigned short)(code), jt, jf, k } |
| 122 | #endif |
| 123 | |
| 124 | /* |
| 125 | * Number of scratch memory words for: BPF_ST and BPF_STX |
| 126 | */ |
| 127 | #define BPF_MEMWORDS 16 |
| 128 | |
| 129 | /* RATIONALE. Negative offsets are invalid in BPF. |
| 130 | We use them to reference ancillary data. |
| 131 | Unlike introduction new instructions, it does not break |
| 132 | existing compilers/optimizers. |
| 133 | */ |
| 134 | #define SKF_AD_OFF (-0x1000) |
| 135 | #define SKF_AD_PROTOCOL 0 |
| 136 | #define SKF_AD_PKTTYPE 4 |
| 137 | #define SKF_AD_IFINDEX 8 |
| 138 | #define SKF_AD_MAX 12 |
| 139 | #define SKF_NET_OFF (-0x100000) |
| 140 | #define SKF_LL_OFF (-0x200000) |
| 141 | |
| 142 | #ifdef __KERNEL__ |
| 143 | struct sk_buff; |
| 144 | struct sock; |
| 145 | |
| 146 | extern int sk_run_filter(struct sk_buff *skb, struct sock_filter *filter, int flen); |
| 147 | extern int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk); |
| 148 | extern int sk_chk_filter(struct sock_filter *filter, int flen); |
| 149 | #endif /* __KERNEL__ */ |
| 150 | |
| 151 | #endif /* __LINUX_FILTER_H__ */ |