include/linux/filter.h

   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 <linux/atomic.h>
  13 #include <linux/compat.h>
  14 #endif
  15
  16 /*
  17  * Current version of the filter code architecture.
  18  */
  19 #define BPF_MAJOR_VERSION 1
  20 #define BPF_MINOR_VERSION 1
  21
  22 /*
  23  *      Try and keep these values and structures similar to BSD, especially
  24  *      the BPF code definitions which need to match so you can share filters
  25  */
  26
  27 struct sock_filter {    /* Filter block */
  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         unsigned short          len;    /* Number of filter blocks */
  36         struct sock_filter __user *filter;
  37 };
  38
  39 /*
  40  * Instruction classes
  41  */
  42
  43 #define BPF_CLASS(code) ((code) & 0x07)
  44 #define         BPF_LD          0x00
  45 #define         BPF_LDX         0x01
  46 #define         BPF_ST          0x02
  47 #define         BPF_STX         0x03
  48 #define         BPF_ALU         0x04
  49 #define         BPF_JMP         0x05
  50 #define         BPF_RET         0x06
  51 #define         BPF_MISC        0x07
  52
  53 /* ld/ldx fields */
  54 #define BPF_SIZE(code)  ((code) & 0x18)
  55 #define         BPF_W           0x00
  56 #define         BPF_H           0x08
  57 #define         BPF_B           0x10
  58 #define BPF_MODE(code)  ((code) & 0xe0)
  59 #define         BPF_IMM         0x00
  60 #define         BPF_ABS         0x20
  61 #define         BPF_IND         0x40
  62 #define         BPF_MEM         0x60
  63 #define         BPF_LEN         0x80
  64 #define         BPF_MSH         0xa0
  65
  66 /* alu/jmp fields */
  67 #define BPF_OP(code)    ((code) & 0xf0)
  68 #define         BPF_ADD         0x00
  69 #define         BPF_SUB         0x10
  70 #define         BPF_MUL         0x20
  71 #define         BPF_DIV         0x30
  72 #define         BPF_OR          0x40
  73 #define         BPF_AND         0x50
  74 #define         BPF_LSH         0x60
  75 #define         BPF_RSH         0x70
  76 #define         BPF_NEG         0x80
  77 #define         BPF_JA          0x00
  78 #define         BPF_JEQ         0x10
  79 #define         BPF_JGT         0x20
  80 #define         BPF_JGE         0x30
  81 #define         BPF_JSET        0x40
  82 #define BPF_SRC(code)   ((code) & 0x08)
  83 #define         BPF_K           0x00
  84 #define         BPF_X           0x08
  85
  86 /* ret - BPF_K and BPF_X also apply */
  87 #define BPF_RVAL(code)  ((code) & 0x18)
  88 #define         BPF_A           0x10
  89
  90 /* misc */
  91 #define BPF_MISCOP(code) ((code) & 0xf8)
  92 #define         BPF_TAX         0x00
  93 #define         BPF_TXA         0x80
  94
  95 #ifndef BPF_MAXINSNS
  96 #define BPF_MAXINSNS 4096
  97 #endif
  98
  99 /*
 100  * Macros for filter block array initializers.
 101  */
 102 #ifndef BPF_STMT
 103 #define BPF_STMT(code, k) { (unsigned short)(code), 0, 0, k }
 104 #endif
 105 #ifndef BPF_JUMP
 106 #define BPF_JUMP(code, k, jt, jf) { (unsigned short)(code), jt, jf, k }
 107 #endif
 108
 109 /*
 110  * Number of scratch memory words for: BPF_ST and BPF_STX
 111  */
 112 #define BPF_MEMWORDS 16
 113
 114 /* RATIONALE. Negative offsets are invalid in BPF.
 115    We use them to reference ancillary data.
 116    Unlike introduction new instructions, it does not break
 117    existing compilers/optimizers.
 118  */
 119 #define SKF_AD_OFF    (-0x1000)
 120 #define SKF_AD_PROTOCOL 0
 121 #define SKF_AD_PKTTYPE  4
 122 #define SKF_AD_IFINDEX  8
 123 #define SKF_AD_NLATTR   12
 124 #define SKF_AD_NLATTR_NEST      16
 125 #define SKF_AD_MARK     20
 126 #define SKF_AD_QUEUE    24
 127 #define SKF_AD_HATYPE   28
 128 #define SKF_AD_RXHASH   32
 129 #define SKF_AD_CPU      36
 130 #define SKF_AD_ALU_XOR_X        40
 131 #define SKF_AD_MAX      44
 132 #define SKF_NET_OFF   (-0x100000)
 133 #define SKF_LL_OFF    (-0x200000)
 134
 135 #ifdef __KERNEL__
 136
 137 #ifdef CONFIG_COMPAT
 138 /*
 139  * A struct sock_filter is architecture independent.
 140  */
 141 struct compat_sock_fprog {
 142         u16             len;
 143         compat_uptr_t   filter;         /* struct sock_filter * */
 144 };
 145 #endif
 146
 147 struct sk_buff;
 148 struct sock;
 149
 150 struct sk_filter
 151 {
 152         atomic_t                refcnt;
 153         unsigned int            len;    /* Number of filter blocks */
 154         unsigned int            (*bpf_func)(const struct sk_buff *skb,
 155                                             const struct sock_filter *filter);
 156         struct rcu_head         rcu;
 157         struct sock_filter      insns[0];
 158 };
 159
 160 static inline unsigned int sk_filter_len(const struct sk_filter *fp)
 161 {
 162         return fp->len * sizeof(struct sock_filter) + sizeof(*fp);
 163 }
 164
 165 extern int sk_filter(struct sock *sk, struct sk_buff *skb);
 166 extern unsigned int sk_run_filter(const struct sk_buff *skb,
 167                                   const struct sock_filter *filter);
 168 extern int sk_unattached_filter_create(struct sk_filter **pfp,
 169                                        struct sock_fprog *fprog);
 170 extern void sk_unattached_filter_destroy(struct sk_filter *fp);
 171 extern int sk_attach_filter(struct sock_fprog *fprog, struct sock *sk);
 172 extern int sk_detach_filter(struct sock *sk);
 173 extern int sk_chk_filter(struct sock_filter *filter, unsigned int flen);
 174
 175 #ifdef CONFIG_BPF_JIT
 176 extern void bpf_jit_compile(struct sk_filter *fp);
 177 extern void bpf_jit_free(struct sk_filter *fp);
 178 #define SK_RUN_FILTER(FILTER, SKB) (*FILTER->bpf_func)(SKB, FILTER->insns)
 179 #else
 180 static inline void bpf_jit_compile(struct sk_filter *fp)
 181 {
 182 }
 183 static inline void bpf_jit_free(struct sk_filter *fp)
 184 {
 185 }
 186 #define SK_RUN_FILTER(FILTER, SKB) sk_run_filter(SKB, FILTER->insns)
 187 #endif
 188
 189 enum {
 190         BPF_S_RET_K = 1,
 191         BPF_S_RET_A,
 192         BPF_S_ALU_ADD_K,
 193         BPF_S_ALU_ADD_X,
 194         BPF_S_ALU_SUB_K,
 195         BPF_S_ALU_SUB_X,
 196         BPF_S_ALU_MUL_K,
 197         BPF_S_ALU_MUL_X,
 198         BPF_S_ALU_DIV_X,
 199         BPF_S_ALU_AND_K,
 200         BPF_S_ALU_AND_X,
 201         BPF_S_ALU_OR_K,
 202         BPF_S_ALU_OR_X,
 203         BPF_S_ALU_LSH_K,
 204         BPF_S_ALU_LSH_X,
 205         BPF_S_ALU_RSH_K,
 206         BPF_S_ALU_RSH_X,
 207         BPF_S_ALU_NEG,
 208         BPF_S_LD_W_ABS,
 209         BPF_S_LD_H_ABS,
 210         BPF_S_LD_B_ABS,
 211         BPF_S_LD_W_LEN,
 212         BPF_S_LD_W_IND,
 213         BPF_S_LD_H_IND,
 214         BPF_S_LD_B_IND,
 215         BPF_S_LD_IMM,
 216         BPF_S_LDX_W_LEN,
 217         BPF_S_LDX_B_MSH,
 218         BPF_S_LDX_IMM,
 219         BPF_S_MISC_TAX,
 220         BPF_S_MISC_TXA,
 221         BPF_S_ALU_DIV_K,
 222         BPF_S_LD_MEM,
 223         BPF_S_LDX_MEM,
 224         BPF_S_ST,
 225         BPF_S_STX,
 226         BPF_S_JMP_JA,
 227         BPF_S_JMP_JEQ_K,
 228         BPF_S_JMP_JEQ_X,
 229         BPF_S_JMP_JGE_K,
 230         BPF_S_JMP_JGE_X,
 231         BPF_S_JMP_JGT_K,
 232         BPF_S_JMP_JGT_X,
 233         BPF_S_JMP_JSET_K,
 234         BPF_S_JMP_JSET_X,
 235         /* Ancillary data */
 236         BPF_S_ANC_PROTOCOL,
 237         BPF_S_ANC_PKTTYPE,
 238         BPF_S_ANC_IFINDEX,
 239         BPF_S_ANC_NLATTR,
 240         BPF_S_ANC_NLATTR_NEST,
 241         BPF_S_ANC_MARK,
 242         BPF_S_ANC_QUEUE,
 243         BPF_S_ANC_HATYPE,
 244         BPF_S_ANC_RXHASH,
 245         BPF_S_ANC_CPU,
 246         BPF_S_ANC_ALU_XOR_X,
 247         BPF_S_ANC_SECCOMP_LD_W,
 248 };
 249
 250 #endif /* __KERNEL__ */
 251
 252 #endif /* __LINUX_FILTER_H__ */