The Tcpdump Group git mirrors - libpcap/blob - pcap/bpf.h

   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 /*
  38  * This is libpcap's cut-down version of bpf.h; it includes only
  39  * the stuff needed for the code generator and the userland BPF
  40  * interpreter, and the libpcap APIs for setting filters, etc..
  41  *
  42  * "pcap-bpf.c" will include the native OS version, as it deals with
  43  * the OS's BPF implementation.
  44  *
  45  * At least two programs found by Google Code Search explicitly includes
  46  * <pcap/bpf.h> (even though <pcap.h>/<pcap/pcap.h> includes it for you),
  47  * so moving that stuff to <pcap/pcap.h> would break the build for some
  48  * programs.
  49  */
  50
  51 /*
  52  * If we've already included <net/bpf.h>, don't re-define this stuff.
  53  * We assume BSD-style multiple-include protection in <net/bpf.h>,
  54  * which is true of all but the oldest versions of FreeBSD and NetBSD,
  55  * or Tru64 UNIX-style multiple-include protection (or, at least,
  56  * Tru64 UNIX 5.x-style; I don't have earlier versions available to check),
  57  * or AIX-style multiple-include protection (or, at least, AIX 5.x-style;
  58  * I don't have earlier versions available to check), or QNX-style
  59  * multiple-include protection (as per GitHub pull request #394).
  60  *
  61  * We trust that they will define structures and macros and types in
  62  * a fashion that's source-compatible and binary-compatible with our
  63  * definitions.
  64  *
  65  * We do not check for BPF_MAJOR_VERSION, as that's defined by
  66  * <linux/filter.h>, which is directly or indirectly included in some
  67  * programs that also include pcap.h, and <linux/filter.h> doesn't
  68  * define stuff we need.  We *do* protect against <linux/filter.h>
  69  * defining various macros for BPF code itself; <linux/filter.h> says
  70  *
  71  *      Try and keep these values and structures similar to BSD, especially
  72  *      the BPF code definitions which need to match so you can share filters
  73  *
  74  * so we trust that it will define them in a fashion that's source-compatible
  75  * and binary-compatible with our definitions.
  76  *
  77  * This also provides our own multiple-include protection.
  78  */
  79 #if !defined(_NET_BPF_H_) && !defined(_NET_BPF_H_INCLUDED) && !defined(_BPF_H_) && !defined(_H_BPF) && !defined(lib_pcap_bpf_h)
  80 #define lib_pcap_bpf_h
  81
  82 #include <pcap/funcattrs.h>
  83 #include <pcap/dlt.h>
  84
  85 #ifdef __cplusplus
  86 extern "C" {
  87 #endif
  88
  89 /* BSD style release date */
  90 #define BPF_RELEASE 199606
  91
  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 /*
 101  * Alignment macros.  BPF_WORDALIGN rounds up to the next
 102  * even multiple of BPF_ALIGNMENT.
 103  *
 104  * Tcpdump's print-pflog.c uses this, so we define it here.
 105  */
 106 #ifndef __NetBSD__
 107 #define BPF_ALIGNMENT sizeof(bpf_int32)
 108 #else
 109 #define BPF_ALIGNMENT sizeof(long)
 110 #endif
 111 #define BPF_WORDALIGN(x) (((x)+(BPF_ALIGNMENT-1))&~(BPF_ALIGNMENT-1))
 112
 113 /*
 114  * Structure for "pcap_compile()", "pcap_setfilter()", etc..
 115  */
 116 struct bpf_program {
 117         u_int bf_len;
 118         struct bpf_insn *bf_insns;
 119 };
 120
 121 /*
 122  * The instruction encodings.
 123  *
 124  * Please inform tcpdump-workers@lists.tcpdump.org if you use any
 125  * of the reserved values, so that we can note that they're used
 126  * (and perhaps implement it in the reference BPF implementation
 127  * and encourage its implementation elsewhere).
 128  */
 129
 130 /*
 131  * The upper 8 bits of the opcode aren't used. BSD/OS used 0x8000.
 132  */
 133
 134 /* instruction classes */
 135 #define BPF_CLASS(code) ((code) & 0x07)
 136 #define         BPF_LD          0x00
 137 #define         BPF_LDX         0x01
 138 #define         BPF_ST          0x02
 139 #define         BPF_STX         0x03
 140 #define         BPF_ALU         0x04
 141 #define         BPF_JMP         0x05
 142 #define         BPF_RET         0x06
 143 #define         BPF_MISC        0x07
 144
 145 /* ld/ldx fields */
 146 #define BPF_SIZE(code)  ((code) & 0x18)
 147 #define         BPF_W           0x00
 148 #define         BPF_H           0x08
 149 #define         BPF_B           0x10
 150 /*                              0x18    reserved; used by BSD/OS */
 151 #define BPF_MODE(code)  ((code) & 0xe0)
 152 #define         BPF_IMM 0x00
 153 #define         BPF_ABS         0x20
 154 #define         BPF_IND         0x40
 155 #define         BPF_MEM         0x60
 156 #define         BPF_LEN         0x80
 157 #define         BPF_MSH         0xa0
 158 /*                              0xc0    reserved; used by BSD/OS */
 159 /*                              0xe0    reserved; used by BSD/OS */
 160
 161 /* alu/jmp fields */
 162 #define BPF_OP(code)    ((code) & 0xf0)
 163 #define         BPF_ADD         0x00
 164 #define         BPF_SUB         0x10
 165 #define         BPF_MUL         0x20
 166 #define         BPF_DIV         0x30
 167 #define         BPF_OR          0x40
 168 #define         BPF_AND         0x50
 169 #define         BPF_LSH         0x60
 170 #define         BPF_RSH         0x70
 171 #define         BPF_NEG         0x80
 172 #define         BPF_MOD         0x90
 173 #define         BPF_XOR         0xa0
 174 /*                              0xb0    reserved */
 175 /*                              0xc0    reserved */
 176 /*                              0xd0    reserved */
 177 /*                              0xe0    reserved */
 178 /*                              0xf0    reserved */
 179
 180 #define         BPF_JA          0x00
 181 #define         BPF_JEQ         0x10
 182 #define         BPF_JGT         0x20
 183 #define         BPF_JGE         0x30
 184 #define         BPF_JSET        0x40
 185 /*                              0x50    reserved; used on BSD/OS */
 186 /*                              0x60    reserved */
 187 /*                              0x70    reserved */
 188 /*                              0x80    reserved */
 189 /*                              0x90    reserved */
 190 /*                              0xa0    reserved */
 191 /*                              0xb0    reserved */
 192 /*                              0xc0    reserved */
 193 /*                              0xd0    reserved */
 194 /*                              0xe0    reserved */
 195 /*                              0xf0    reserved */
 196 #define BPF_SRC(code)   ((code) & 0x08)
 197 #define         BPF_K           0x00
 198 #define         BPF_X           0x08
 199
 200 /* ret - BPF_K and BPF_X also apply */
 201 #define BPF_RVAL(code)  ((code) & 0x18)
 202 #define         BPF_A           0x10
 203 /*                              0x18    reserved */
 204
 205 /* misc */
 206 #define BPF_MISCOP(code) ((code) & 0xf8)
 207 #define         BPF_TAX         0x00
 208 /*                              0x08    reserved */
 209 /*                              0x10    reserved */
 210 /*                              0x18    reserved */
 211 /* #define      BPF_COP         0x20    NetBSD "coprocessor" extensions */
 212 /*                              0x28    reserved */
 213 /*                              0x30    reserved */
 214 /*                              0x38    reserved */
 215 /* #define      BPF_COPX        0x40    NetBSD "coprocessor" extensions */
 216 /*                                      also used on BSD/OS */
 217 /*                              0x48    reserved */
 218 /*                              0x50    reserved */
 219 /*                              0x58    reserved */
 220 /*                              0x60    reserved */
 221 /*                              0x68    reserved */
 222 /*                              0x70    reserved */
 223 /*                              0x78    reserved */
 224 #define         BPF_TXA         0x80
 225 /*                              0x88    reserved */
 226 /*                              0x90    reserved */
 227 /*                              0x98    reserved */
 228 /*                              0xa0    reserved */
 229 /*                              0xa8    reserved */
 230 /*                              0xb0    reserved */
 231 /*                              0xb8    reserved */
 232 /*                              0xc0    reserved; used on BSD/OS */
 233 /*                              0xc8    reserved */
 234 /*                              0xd0    reserved */
 235 /*                              0xd8    reserved */
 236 /*                              0xe0    reserved */
 237 /*                              0xe8    reserved */
 238 /*                              0xf0    reserved */
 239 /*                              0xf8    reserved */
 240
 241 /*
 242  * The instruction data structure.
 243  */
 244 struct bpf_insn {
 245         u_short code;
 246         u_char  jt;
 247         u_char  jf;
 248         bpf_u_int32 k;
 249 };
 250
 251 /*
 252  * Macros for insn array initializers.
 253  *
 254  * In case somebody's included <linux/filter.h>, or something else that
 255  * gives the kernel's definitions of BPF statements, get rid of its
 256  * definitions, so we can supply ours instead.  If some kernel's
 257  * definitions aren't *binary-compatible* with what BPF has had
 258  * since it first sprung from the brows of Van Jacobson and Steve
 259  * McCanne, that kernel should be fixed.
 260  */
 261 #ifdef BPF_STMT
 262 #undef BPF_STMT
 263 #endif
 264 #define BPF_STMT(code, k) { (u_short)(code), 0, 0, k }
 265 #ifdef BPF_JUMP
 266 #undef BPF_JUMP
 267 #endif
 268 #define BPF_JUMP(code, k, jt, jf) { (u_short)(code), jt, jf, k }
 269
 270 PCAP_AVAILABLE_0_4
 271 PCAP_API u_int  bpf_filter(const struct bpf_insn *, const u_char *, u_int, u_int);
 272
 273 PCAP_AVAILABLE_0_6
 274 PCAP_API int    bpf_validate(const struct bpf_insn *f, int len);
 275
 276 PCAP_AVAILABLE_0_4
 277 PCAP_API char   *bpf_image(const struct bpf_insn *, int);
 278
 279 PCAP_AVAILABLE_0_6
 280 PCAP_API void   bpf_dump(const struct bpf_program *, int);
 281
 282 /*
 283  * Number of scratch memory words (for BPF_LD|BPF_MEM and BPF_ST).
 284  */
 285 #define BPF_MEMWORDS 16
 286
 287 #ifdef __cplusplus
 288 }
 289 #endif
 290
 291 #endif /* !defined(_NET_BPF_H_) && !defined(_BPF_H_) && !defined(_H_BPF) && !defined(lib_pcap_bpf_h) */