bpf.h

Go to the documentation of this file.

/*
 * Copyright (c) 1990, 1991, 1993
 *      The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from the Stanford/CMU enet packet filter,
 * (net/enet.c) distributed as part of 4.3BSD, and code contributed
 * to Berkeley by Steven McCanne and Van Jacobson both of Lawrence
 * Berkeley Laboratory.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *      This product includes software developed by the University of
 *      California, Berkeley and its contributors.
 * 4. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *      @(#)bpf.h       8.1 (Berkeley) 6/10/93
 *      @(#)bpf.h       1.34 (LBL)     6/16/96
 */

#ifndef _NET_BPF_H_
#define _NET_BPF_H_

#include <sys/time.h> /* struct timeval */

/* BSD style release date */
#define BPF_RELEASE 199606

typedef int32_t   bpf_int32;
typedef u_int32_t bpf_u_int32;

/*
 * Alignment macros.  BPF_WORDALIGN rounds up to the next
 * even multiple of BPF_ALIGNMENT.
 */
#define BPF_ALIGNMENT sizeof(bpf_int32)
#define BPF_WORDALIGN(x) (((x)+(BPF_ALIGNMENT-1))&~(BPF_ALIGNMENT-1))

#define BPF_MAXINSNS 512
#define BPF_MAXBUFSIZE 0x8000
#define BPF_MINBUFSIZE 32

/*
 *  Structure for BIOCSETF.
 */
struct bpf_program {
        u_int bf_len;
        struct bpf_insn *bf_insns;
};

/*
 * Struct returned by BIOCGSTATS.
 */
struct bpf_stat {
        u_int bs_recv;          /* number of packets received */
        u_int bs_drop;          /* number of packets dropped */
};

/*
 * Struct return by BIOCVERSION.  This represents the version number of
 * the filter language described by the instruction encodings below.
 * bpf understands a program iff kernel_major == filter_major &&
 * kernel_minor >= filter_minor, that is, if the value returned by the
 * running kernel has the same major number and a minor number equal
 * equal to or less than the filter being downloaded.  Otherwise, the
 * results are undefined, meaning an error may be returned or packets
 * may be accepted haphazardly.
 * It has nothing to do with the source code version.
 */
struct bpf_version {
        u_short bv_major;
        u_short bv_minor;
};
/* Current version number of filter architecture. */
#define BPF_MAJOR_VERSION 1
#define BPF_MINOR_VERSION 1

#define BIOCGBLEN       _IOR('B',102, u_int)
#define BIOCSBLEN       _IOWR('B',102, u_int)
#define BIOCSETF        _IOW('B',103, struct bpf_program)
#define BIOCFLUSH       _IO('B',104)
#define BIOCPROMISC     _IO('B',105)
#define BIOCGDLT        _IOR('B',106, u_int)
#define BIOCGETIF       _IOR('B',107, struct ifreq)
#define BIOCSETIF       _IOW('B',108, struct ifreq)
#define BIOCSRTIMEOUT   _IOW('B',109, struct timeval)
#define BIOCGRTIMEOUT   _IOR('B',110, struct timeval)
#define BIOCGSTATS      _IOR('B',111, struct bpf_stat)
#define BIOCIMMEDIATE   _IOW('B',112, u_int)
#define BIOCVERSION     _IOR('B',113, struct bpf_version)
#define BIOCGRSIG       _IOR('B',114, u_int)
#define BIOCSRSIG       _IOW('B',115, u_int)

/*
 * Structure prepended to each packet.
 */
struct bpf_hdr {
        struct timeval  bh_tstamp;      /* time stamp */
        bpf_u_int32     bh_caplen;      /* length of captured portion */
        bpf_u_int32     bh_datalen;     /* original length of packet */
        u_short         bh_hdrlen;      /* length of bpf header (this struct
                                           plus alignment padding) */
};
/*
 * Because the structure above is not a multiple of 4 bytes, some compilers
 * will insist on inserting padding; hence, sizeof(struct bpf_hdr) won't work.
 * Only the kernel needs to know about it; applications use bh_hdrlen.
 */
#ifdef _KERNEL
#define SIZEOF_BPF_HDR 18
#endif

/*
 * Data-link level type codes.
 */
#define DLT_NULL        0       /* no link-layer encapsulation */
#define DLT_EN10MB      1       /* Ethernet (10Mb) */
#define DLT_EN3MB       2       /* Experimental Ethernet (3Mb) */
#define DLT_AX25        3       /* Amateur Radio AX.25 */
#define DLT_PRONET      4       /* Proteon ProNET Token Ring */
#define DLT_CHAOS       5       /* Chaos */
#define DLT_IEEE802     6       /* IEEE 802 Networks */
#define DLT_ARCNET      7       /* ARCNET */
#define DLT_SLIP        8       /* Serial Line IP */
#define DLT_PPP         9       /* Point-to-point Protocol */
#define DLT_FDDI        10      /* FDDI */
#define DLT_ATM_RFC1483 11      /* LLC/SNAP encapsulated atm */

/*
 * The instruction encodings.
 */
/* instruction classes */
#define BPF_CLASS(code) ((code) & 0x07)
#define         BPF_LD          0x00
#define         BPF_LDX         0x01
#define         BPF_ST          0x02
#define         BPF_STX         0x03
#define         BPF_ALU         0x04
#define         BPF_JMP         0x05
#define         BPF_RET         0x06
#define         BPF_MISC        0x07

/* ld/ldx fields */
#define BPF_SIZE(code)  ((code) & 0x18)
#define         BPF_W           0x00
#define         BPF_H           0x08
#define         BPF_B           0x10
#define BPF_MODE(code)  ((code) & 0xe0)
#define         BPF_IMM         0x00
#define         BPF_ABS         0x20
#define         BPF_IND         0x40
#define         BPF_MEM         0x60
#define         BPF_LEN         0x80
#define         BPF_MSH         0xa0

/* alu/jmp fields */
#define BPF_OP(code)    ((code) & 0xf0)
#define         BPF_ADD         0x00
#define         BPF_SUB         0x10
#define         BPF_MUL         0x20
#define         BPF_DIV         0x30
#define         BPF_OR          0x40
#define         BPF_AND         0x50
#define         BPF_LSH         0x60
#define         BPF_RSH         0x70
#define         BPF_NEG         0x80
#define         BPF_JA          0x00
#define         BPF_JEQ         0x10
#define         BPF_JGT         0x20
#define         BPF_JGE         0x30
#define         BPF_JSET        0x40
#define BPF_SRC(code)   ((code) & 0x08)
#define         BPF_K           0x00
#define         BPF_X           0x08

/* ret - BPF_K and BPF_X also apply */
#define BPF_RVAL(code)  ((code) & 0x18)
#define         BPF_A           0x10

/* misc */
#define BPF_MISCOP(code) ((code) & 0xf8)
#define         BPF_TAX         0x00
#define         BPF_TXA         0x80

/*
 * The instruction data structure.
 */
struct bpf_insn {
        u_short         code;
        u_char          jt;
        u_char          jf;
        bpf_u_int32     k;
};

/*
 * Macros for insn array initializers.
 */
#define BPF_STMT(code, k) { (u_short)(code), 0, 0, k }
#define BPF_JUMP(code, k, jt, jf) { (u_short)(code), jt, jf, k }

#ifdef _KERNEL
int      bpf_validate(struct bpf_insn *, int);
void     bpf_tap(struct ifnet *, u_char *, u_int);
void     bpf_mtap(struct ifnet *, struct mbuf *);
void     bpfattach(struct ifnet *, u_int, u_int);
void     bpfilterattach(int);
u_int    bpf_filter(const struct bpf_insn *, u_char *, u_int, u_int);
#endif

/*
 * Number of scratch memory words (for BPF_LD|BPF_MEM and BPF_ST).
 */
#define BPF_MEMWORDS 16

#endif /* _NET_BPF_H_ */