bpf.h 9.3 KB

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  1. /*-
  2. * Copyright (c) 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997
  3. * The Regents of the University of California. All rights reserved.
  4. *
  5. * This code is derived from the Stanford/CMU enet packet filter,
  6. * (net/enet.c) distributed as part of 4.3BSD, and code contributed
  7. * to Berkeley by Steven McCanne and Van Jacobson both of Lawrence
  8. * Berkeley Laboratory.
  9. *
  10. * Redistribution and use in source and binary forms, with or without
  11. * modification, are permitted provided that the following conditions
  12. * are met:
  13. * 1. Redistributions of source code must retain the above copyright
  14. * notice, this list of conditions and the following disclaimer.
  15. * 2. Redistributions in binary form must reproduce the above copyright
  16. * notice, this list of conditions and the following disclaimer in the
  17. * documentation and/or other materials provided with the distribution.
  18. * 3. Neither the name of the University nor the names of its contributors
  19. * may be used to endorse or promote products derived from this software
  20. * without specific prior written permission.
  21. *
  22. * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23. * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24. * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25. * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26. * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27. * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28. * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29. * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30. * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31. * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32. * SUCH DAMAGE.
  33. *
  34. * @(#)bpf.h 7.1 (Berkeley) 5/7/91
  35. */
  36. /*
  37. * This is libpcap's cut-down version of bpf.h; it includes only
  38. * the stuff needed for the code generator and the userland BPF
  39. * interpreter, and the libpcap APIs for setting filters, etc..
  40. *
  41. * "pcap-bpf.c" will include the native OS version, as it deals with
  42. * the OS's BPF implementation.
  43. *
  44. * At least two programs found by Google Code Search explicitly includes
  45. * <pcap/bpf.h> (even though <pcap.h>/<pcap/pcap.h> includes it for you),
  46. * so moving that stuff to <pcap/pcap.h> would break the build for some
  47. * programs.
  48. */
  49. /*
  50. * If we've already included <net/bpf.h>, don't re-define this stuff.
  51. * We assume BSD-style multiple-include protection in <net/bpf.h>,
  52. * which is true of all but the oldest versions of FreeBSD and NetBSD,
  53. * or Tru64 UNIX-style multiple-include protection (or, at least,
  54. * Tru64 UNIX 5.x-style; I don't have earlier versions available to check),
  55. * or AIX-style multiple-include protection (or, at least, AIX 5.x-style;
  56. * I don't have earlier versions available to check), or QNX-style
  57. * multiple-include protection (as per GitHub pull request #394).
  58. *
  59. * We trust that they will define structures and macros and types in
  60. * a fashion that's source-compatible and binary-compatible with our
  61. * definitions.
  62. *
  63. * We do not check for BPF_MAJOR_VERSION, as that's defined by
  64. * <linux/filter.h>, which is directly or indirectly included in some
  65. * programs that also include pcap.h, and <linux/filter.h> doesn't
  66. * define stuff we need. We *do* protect against <linux/filter.h>
  67. * defining various macros for BPF code itself; <linux/filter.h> says
  68. *
  69. * Try and keep these values and structures similar to BSD, especially
  70. * the BPF code definitions which need to match so you can share filters
  71. *
  72. * so we trust that it will define them in a fashion that's source-compatible
  73. * and binary-compatible with our definitions.
  74. *
  75. * This also provides our own multiple-include protection.
  76. */
  77. #if !defined(_NET_BPF_H_) && !defined(_NET_BPF_H_INCLUDED) && !defined(_BPF_H_) && !defined(_H_BPF) && !defined(lib_pcap_bpf_h)
  78. #define lib_pcap_bpf_h
  79. /* u_char, u_short and u_int */
  80. #if defined(_WIN32)
  81. #include <winsock2.h>
  82. #elif defined(HAVE_SYS_TYPES_H)
  83. #include <sys/types.h>
  84. #endif
  85. #include <pcap/funcattrs.h>
  86. #include <pcap/dlt.h>
  87. #ifdef __cplusplus
  88. extern "C" {
  89. #endif
  90. /* BSD style release date */
  91. #define BPF_RELEASE 199606
  92. #ifdef MSDOS /* must be 32-bit */
  93. typedef long bpf_int32;
  94. typedef unsigned long bpf_u_int32;
  95. #else
  96. typedef int bpf_int32;
  97. typedef u_int bpf_u_int32;
  98. #endif
  99. /*
  100. * Alignment macros. BPF_WORDALIGN rounds up to the next
  101. * even multiple of BPF_ALIGNMENT.
  102. *
  103. * Tcpdump's print-pflog.c uses this, so we define it here.
  104. */
  105. #ifndef __NetBSD__
  106. #define BPF_ALIGNMENT sizeof(bpf_int32)
  107. #else
  108. #define BPF_ALIGNMENT sizeof(long)
  109. #endif
  110. #define BPF_WORDALIGN(x) (((x)+(BPF_ALIGNMENT-1))&~(BPF_ALIGNMENT-1))
  111. /*
  112. * Structure for "pcap_compile()", "pcap_setfilter()", etc..
  113. */
  114. struct bpf_program {
  115. u_int bf_len;
  116. struct bpf_insn *bf_insns;
  117. };
  118. /*
  119. * The instruction encodings.
  120. *
  121. * Please inform tcpdump-workers@lists.tcpdump.org if you use any
  122. * of the reserved values, so that we can note that they're used
  123. * (and perhaps implement it in the reference BPF implementation
  124. * and encourage its implementation elsewhere).
  125. */
  126. /*
  127. * The upper 8 bits of the opcode aren't used. BSD/OS used 0x8000.
  128. */
  129. /* instruction classes */
  130. #define BPF_CLASS(code) ((code) & 0x07)
  131. #define BPF_LD 0x00
  132. #define BPF_LDX 0x01
  133. #define BPF_ST 0x02
  134. #define BPF_STX 0x03
  135. #define BPF_ALU 0x04
  136. #define BPF_JMP 0x05
  137. #define BPF_RET 0x06
  138. #define BPF_MISC 0x07
  139. /* ld/ldx fields */
  140. #define BPF_SIZE(code) ((code) & 0x18)
  141. #define BPF_W 0x00
  142. #define BPF_H 0x08
  143. #define BPF_B 0x10
  144. /* 0x18 reserved; used by BSD/OS */
  145. #define BPF_MODE(code) ((code) & 0xe0)
  146. #define BPF_IMM 0x00
  147. #define BPF_ABS 0x20
  148. #define BPF_IND 0x40
  149. #define BPF_MEM 0x60
  150. #define BPF_LEN 0x80
  151. #define BPF_MSH 0xa0
  152. /* 0xc0 reserved; used by BSD/OS */
  153. /* 0xe0 reserved; used by BSD/OS */
  154. /* alu/jmp fields */
  155. #define BPF_OP(code) ((code) & 0xf0)
  156. #define BPF_ADD 0x00
  157. #define BPF_SUB 0x10
  158. #define BPF_MUL 0x20
  159. #define BPF_DIV 0x30
  160. #define BPF_OR 0x40
  161. #define BPF_AND 0x50
  162. #define BPF_LSH 0x60
  163. #define BPF_RSH 0x70
  164. #define BPF_NEG 0x80
  165. #define BPF_MOD 0x90
  166. #define BPF_XOR 0xa0
  167. /* 0xb0 reserved */
  168. /* 0xc0 reserved */
  169. /* 0xd0 reserved */
  170. /* 0xe0 reserved */
  171. /* 0xf0 reserved */
  172. #define BPF_JA 0x00
  173. #define BPF_JEQ 0x10
  174. #define BPF_JGT 0x20
  175. #define BPF_JGE 0x30
  176. #define BPF_JSET 0x40
  177. /* 0x50 reserved; used on BSD/OS */
  178. /* 0x60 reserved */
  179. /* 0x70 reserved */
  180. /* 0x80 reserved */
  181. /* 0x90 reserved */
  182. /* 0xa0 reserved */
  183. /* 0xb0 reserved */
  184. /* 0xc0 reserved */
  185. /* 0xd0 reserved */
  186. /* 0xe0 reserved */
  187. /* 0xf0 reserved */
  188. #define BPF_SRC(code) ((code) & 0x08)
  189. #define BPF_K 0x00
  190. #define BPF_X 0x08
  191. /* ret - BPF_K and BPF_X also apply */
  192. #define BPF_RVAL(code) ((code) & 0x18)
  193. #define BPF_A 0x10
  194. /* 0x18 reserved */
  195. /* misc */
  196. #define BPF_MISCOP(code) ((code) & 0xf8)
  197. #define BPF_TAX 0x00
  198. /* 0x08 reserved */
  199. /* 0x10 reserved */
  200. /* 0x18 reserved */
  201. /* #define BPF_COP 0x20 NetBSD "coprocessor" extensions */
  202. /* 0x28 reserved */
  203. /* 0x30 reserved */
  204. /* 0x38 reserved */
  205. /* #define BPF_COPX 0x40 NetBSD "coprocessor" extensions */
  206. /* also used on BSD/OS */
  207. /* 0x48 reserved */
  208. /* 0x50 reserved */
  209. /* 0x58 reserved */
  210. /* 0x60 reserved */
  211. /* 0x68 reserved */
  212. /* 0x70 reserved */
  213. /* 0x78 reserved */
  214. #define BPF_TXA 0x80
  215. /* 0x88 reserved */
  216. /* 0x90 reserved */
  217. /* 0x98 reserved */
  218. /* 0xa0 reserved */
  219. /* 0xa8 reserved */
  220. /* 0xb0 reserved */
  221. /* 0xb8 reserved */
  222. /* 0xc0 reserved; used on BSD/OS */
  223. /* 0xc8 reserved */
  224. /* 0xd0 reserved */
  225. /* 0xd8 reserved */
  226. /* 0xe0 reserved */
  227. /* 0xe8 reserved */
  228. /* 0xf0 reserved */
  229. /* 0xf8 reserved */
  230. /*
  231. * The instruction data structure.
  232. */
  233. struct bpf_insn {
  234. u_short code;
  235. u_char jt;
  236. u_char jf;
  237. bpf_u_int32 k;
  238. };
  239. /*
  240. * Macros for insn array initializers.
  241. *
  242. * In case somebody's included <linux/filter.h>, or something else that
  243. * gives the kernel's definitions of BPF statements, get rid of its
  244. * definitions, so we can supply ours instead. If some kernel's
  245. * definitions aren't *binary-compatible* with what BPF has had
  246. * since it first sprung from the brows of Van Jacobson and Steve
  247. * McCanne, that kernel should be fixed.
  248. */
  249. #ifdef BPF_STMT
  250. #undef BPF_STMT
  251. #endif
  252. #define BPF_STMT(code, k) { (u_short)(code), 0, 0, k }
  253. #ifdef BPF_JUMP
  254. #undef BPF_JUMP
  255. #endif
  256. #define BPF_JUMP(code, k, jt, jf) { (u_short)(code), jt, jf, k }
  257. PCAP_AVAILABLE_0_4
  258. PCAP_API u_int bpf_filter(const struct bpf_insn *, const u_char *, u_int, u_int);
  259. PCAP_AVAILABLE_0_6
  260. PCAP_API int bpf_validate(const struct bpf_insn *f, int len);
  261. PCAP_AVAILABLE_0_4
  262. PCAP_API char *bpf_image(const struct bpf_insn *, int);
  263. PCAP_AVAILABLE_0_6
  264. PCAP_API void bpf_dump(const struct bpf_program *, int);
  265. /*
  266. * Number of scratch memory words (for BPF_LD|BPF_MEM and BPF_ST).
  267. */
  268. #define BPF_MEMWORDS 16
  269. #ifdef __cplusplus
  270. }
  271. #endif
  272. #endif /* !defined(_NET_BPF_H_) && !defined(_BPF_H_) && !defined(_H_BPF) && !defined(lib_pcap_bpf_h) */