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 __u16 code; /* Actual filter code */ 28 __u8 jt; /* Jump true */ 29 __u8 jf; /* Jump false */ 30 __u32 k; /* Generic multiuse field */ 31 }; 32 33 struct sock_fprog { /* Required for SO_ATTACH_FILTER. */ 34 unsigned short len; /* Number of filter blocks */ 35 struct sock_filter __user *filter; 36 }; 37 38 /* 39 * Instruction classes 40 */ 41 42 #define BPF_CLASS(code) ((code) & 0x07) 43 #define BPF_LD 0x00 44 #define BPF_LDX 0x01 45 #define BPF_ST 0x02 46 #define BPF_STX 0x03 47 #define BPF_ALU 0x04 48 #define BPF_JMP 0x05 49 #define BPF_RET 0x06 50 #define BPF_MISC 0x07 51 52 /* ld/ldx fields */ 53 #define BPF_SIZE(code) ((code) & 0x18) 54 #define BPF_W 0x00 55 #define BPF_H 0x08 56 #define BPF_B 0x10 57 #define BPF_MODE(code) ((code) & 0xe0) 58 #define BPF_IMM 0x00 59 #define BPF_ABS 0x20 60 #define BPF_IND 0x40 61 #define BPF_MEM 0x60 62 #define BPF_LEN 0x80 63 #define BPF_MSH 0xa0 64 65 /* alu/jmp fields */ 66 #define BPF_OP(code) ((code) & 0xf0) 67 #define BPF_ADD 0x00 68 #define BPF_SUB 0x10 69 #define BPF_MUL 0x20 70 #define BPF_DIV 0x30 71 #define BPF_OR 0x40 72 #define BPF_AND 0x50 73 #define BPF_LSH 0x60 74 #define BPF_RSH 0x70 75 #define BPF_NEG 0x80 76 #define BPF_JA 0x00 77 #define BPF_JEQ 0x10 78 #define BPF_JGT 0x20 79 #define BPF_JGE 0x30 80 #define BPF_JSET 0x40 81 #define BPF_SRC(code) ((code) & 0x08) 82 #define BPF_K 0x00 83 #define BPF_X 0x08 84 85 /* ret - BPF_K and BPF_X also apply */ 86 #define BPF_RVAL(code) ((code) & 0x18) 87 #define BPF_A 0x10 88 89 /* misc */ 90 #define BPF_MISCOP(code) ((code) & 0xf8) 91 #define BPF_TAX 0x00 92 #define BPF_TXA 0x80 93 94 #ifndef BPF_MAXINSNS 95 #define BPF_MAXINSNS 4096 96 #endif 97 98 /* 99 * Macros for filter block array initializers. 100 */ 101 #ifndef BPF_STMT 102 #define BPF_STMT(code, k) { (unsigned short)(code), 0, 0, k } 103 #endif 104 #ifndef BPF_JUMP 105 #define BPF_JUMP(code, k, jt, jf) { (unsigned short)(code), jt, jf, k } 106 #endif 107 108 /* 109 * Number of scratch memory words for: BPF_ST and BPF_STX 110 */ 111 #define BPF_MEMWORDS 16 112 113 /* RATIONALE. Negative offsets are invalid in BPF. 114 We use them to reference ancillary data. 115 Unlike introduction new instructions, it does not break 116 existing compilers/optimizers. 117 */ 118 #define SKF_AD_OFF (-0x1000) 119 #define SKF_AD_PROTOCOL 0 120 #define SKF_AD_PKTTYPE 4 121 #define SKF_AD_IFINDEX 8 122 #define SKF_AD_NLATTR 12 123 #define SKF_AD_NLATTR_NEST 16 124 #define SKF_AD_MARK 20 125 #define SKF_AD_QUEUE 24 126 #define SKF_AD_MAX 28 127 #define SKF_NET_OFF (-0x100000) 128 #define SKF_LL_OFF (-0x200000) 129 130 #ifdef __KERNEL__ 131 struct sk_filter 132 { 133 atomic_t refcnt; 134 unsigned int len; /* Number of filter blocks */ 135 struct rcu_head rcu; 136 struct sock_filter insns[0]; 137 }; 138 139 static inline unsigned int sk_filter_len(const struct sk_filter *fp) 140 { 141 return fp->len * sizeof(struct sock_filter) + sizeof(*fp); 142 } 143 144 struct sk_buff; 145 struct sock; 146 147 extern int sk_filter(struct sock *sk, struct sk_buff *skb); 148 extern unsigned int sk_run_filter(struct sk_buff *skb, 149 struct sock_filter *filter, int flen); 150 extern int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk); 151 extern int sk_detach_filter(struct sock *sk); 152 extern int sk_chk_filter(struct sock_filter *filter, int flen); 153 #endif /* __KERNEL__ */ 154 155 #endif /* __LINUX_FILTER_H__ */ 156