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 rcu_head rcu; 46 struct sock_filter insns[0]; 47 }; 48 49 static inline unsigned int sk_filter_len(struct sk_filter *fp) 50 { 51 return fp->len*sizeof(struct sock_filter) + sizeof(*fp); 52 } 53 #endif 54 55 /* 56 * Instruction classes 57 */ 58 59 #define BPF_CLASS(code) ((code) & 0x07) 60 #define BPF_LD 0x00 61 #define BPF_LDX 0x01 62 #define BPF_ST 0x02 63 #define BPF_STX 0x03 64 #define BPF_ALU 0x04 65 #define BPF_JMP 0x05 66 #define BPF_RET 0x06 67 #define BPF_MISC 0x07 68 69 /* ld/ldx fields */ 70 #define BPF_SIZE(code) ((code) & 0x18) 71 #define BPF_W 0x00 72 #define BPF_H 0x08 73 #define BPF_B 0x10 74 #define BPF_MODE(code) ((code) & 0xe0) 75 #define BPF_IMM 0x00 76 #define BPF_ABS 0x20 77 #define BPF_IND 0x40 78 #define BPF_MEM 0x60 79 #define BPF_LEN 0x80 80 #define BPF_MSH 0xa0 81 82 /* alu/jmp fields */ 83 #define BPF_OP(code) ((code) & 0xf0) 84 #define BPF_ADD 0x00 85 #define BPF_SUB 0x10 86 #define BPF_MUL 0x20 87 #define BPF_DIV 0x30 88 #define BPF_OR 0x40 89 #define BPF_AND 0x50 90 #define BPF_LSH 0x60 91 #define BPF_RSH 0x70 92 #define BPF_NEG 0x80 93 #define BPF_JA 0x00 94 #define BPF_JEQ 0x10 95 #define BPF_JGT 0x20 96 #define BPF_JGE 0x30 97 #define BPF_JSET 0x40 98 #define BPF_SRC(code) ((code) & 0x08) 99 #define BPF_K 0x00 100 #define BPF_X 0x08 101 102 /* ret - BPF_K and BPF_X also apply */ 103 #define BPF_RVAL(code) ((code) & 0x18) 104 #define BPF_A 0x10 105 106 /* misc */ 107 #define BPF_MISCOP(code) ((code) & 0xf8) 108 #define BPF_TAX 0x00 109 #define BPF_TXA 0x80 110 111 #ifndef BPF_MAXINSNS 112 #define BPF_MAXINSNS 4096 113 #endif 114 115 /* 116 * Macros for filter block array initializers. 117 */ 118 #ifndef BPF_STMT 119 #define BPF_STMT(code, k) { (unsigned short)(code), 0, 0, k } 120 #endif 121 #ifndef BPF_JUMP 122 #define BPF_JUMP(code, k, jt, jf) { (unsigned short)(code), jt, jf, k } 123 #endif 124 125 /* 126 * Number of scratch memory words for: BPF_ST and BPF_STX 127 */ 128 #define BPF_MEMWORDS 16 129 130 /* RATIONALE. Negative offsets are invalid in BPF. 131 We use them to reference ancillary data. 132 Unlike introduction new instructions, it does not break 133 existing compilers/optimizers. 134 */ 135 #define SKF_AD_OFF (-0x1000) 136 #define SKF_AD_PROTOCOL 0 137 #define SKF_AD_PKTTYPE 4 138 #define SKF_AD_IFINDEX 8 139 #define SKF_AD_MAX 12 140 #define SKF_NET_OFF (-0x100000) 141 #define SKF_LL_OFF (-0x200000) 142 143 #ifdef __KERNEL__ 144 struct sk_buff; 145 struct sock; 146 147 extern unsigned int sk_run_filter(struct sk_buff *skb, struct sock_filter *filter, int flen); 148 extern int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk); 149 extern int sk_detach_filter(struct sock *sk); 150 extern int sk_chk_filter(struct sock_filter *filter, int flen); 151 #endif /* __KERNEL__ */ 152 153 #endif /* __LINUX_FILTER_H__ */ 154