filter.h 3.9 KB

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