FreeBSD/Linux Kernel Cross Reference
sys/net/bpf.h

     /*-
      * SPDX-License-Identifier: BSD-3-Clause
      *
      * 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. 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
     *
     * $FreeBSD: releng/12.0/sys/net/bpf.h 326023 2017-11-20 19:43:44Z pfg $
     */
    
    #ifndef _NET_BPF_H_
    #define _NET_BPF_H_
    
    /* BSD style release date */
    #define BPF_RELEASE 199606
    
    typedef int32_t   bpf_int32;
    typedef u_int32_t bpf_u_int32;
    typedef int64_t   bpf_int64;
    typedef u_int64_t bpf_u_int64;
    
    /*
     * Alignment macros.  BPF_WORDALIGN rounds up to the next
     * even multiple of BPF_ALIGNMENT.
     */
    #define BPF_ALIGNMENT sizeof(long)
    #define BPF_WORDALIGN(x) (((x)+(BPF_ALIGNMENT-1))&~(BPF_ALIGNMENT-1))
    
    #define BPF_MAXINSNS 512
    #define BPF_MAXBUFSIZE 0x80000
    #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
    
    /*
    * Historically, BPF has supported a single buffering model, first using mbuf
    * clusters in kernel, and later using malloc(9) buffers in kernel.  We now
    * support multiple buffering modes, which may be queried and set using
    * BIOCGETBUFMODE and BIOCSETBUFMODE.  So as to avoid handling the complexity
    * of changing modes while sniffing packets, the mode becomes fixed once an
    * interface has been attached to the BPF descriptor.
    */
   #define BPF_BUFMODE_BUFFER      1       /* Kernel buffers with read(). */
   #define BPF_BUFMODE_ZBUF        2       /* Zero-copy buffers. */
   
   /*-
    * Struct used by BIOCSETZBUF, BIOCROTZBUF: describes up to two zero-copy
    * buffer as used by BPF.
    */
   struct bpf_zbuf {
           void    *bz_bufa;       /* Location of 'a' zero-copy buffer. */
           void    *bz_bufb;       /* Location of 'b' zero-copy buffer. */
           size_t   bz_buflen;     /* Size of zero-copy buffers. */
   };
   
   #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)
   #define BIOCGHDRCMPLT   _IOR('B', 116, u_int)
   #define BIOCSHDRCMPLT   _IOW('B', 117, u_int)
   #define BIOCGDIRECTION  _IOR('B', 118, u_int)
   #define BIOCSDIRECTION  _IOW('B', 119, u_int)
   #define BIOCSDLT        _IOW('B', 120, u_int)
   #define BIOCGDLTLIST    _IOWR('B', 121, struct bpf_dltlist)
   #define BIOCLOCK        _IO('B', 122)
   #define BIOCSETWF       _IOW('B', 123, struct bpf_program)
   #define BIOCFEEDBACK    _IOW('B', 124, u_int)
   #define BIOCGETBUFMODE  _IOR('B', 125, u_int)
   #define BIOCSETBUFMODE  _IOW('B', 126, u_int)
   #define BIOCGETZMAX     _IOR('B', 127, size_t)
   #define BIOCROTZBUF     _IOR('B', 128, struct bpf_zbuf)
   #define BIOCSETZBUF     _IOW('B', 129, struct bpf_zbuf)
   #define BIOCSETFNR      _IOW('B', 130, struct bpf_program)
   #define BIOCGTSTAMP     _IOR('B', 131, u_int)
   #define BIOCSTSTAMP     _IOW('B', 132, u_int)
   
   /* Obsolete */
   #define BIOCGSEESENT    BIOCGDIRECTION
   #define BIOCSSEESENT    BIOCSDIRECTION
   
   /* Packet directions */
   enum bpf_direction {
           BPF_D_IN,       /* See incoming packets */
           BPF_D_INOUT,    /* See incoming and outgoing packets */
           BPF_D_OUT       /* See outgoing packets */
   };
   
   /* Time stamping functions */
   #define BPF_T_MICROTIME         0x0000
   #define BPF_T_NANOTIME          0x0001
   #define BPF_T_BINTIME           0x0002
   #define BPF_T_NONE              0x0003
   #define BPF_T_FORMAT_MASK       0x0003
   #define BPF_T_NORMAL            0x0000
   #define BPF_T_FAST              0x0100
   #define BPF_T_MONOTONIC         0x0200
   #define BPF_T_MONOTONIC_FAST    (BPF_T_FAST | BPF_T_MONOTONIC)
   #define BPF_T_FLAG_MASK         0x0300
   #define BPF_T_FORMAT(t)         ((t) & BPF_T_FORMAT_MASK)
   #define BPF_T_FLAG(t)           ((t) & BPF_T_FLAG_MASK)
   #define BPF_T_VALID(t)                                          \
       ((t) == BPF_T_NONE || (BPF_T_FORMAT(t) != BPF_T_NONE &&     \
       ((t) & ~(BPF_T_FORMAT_MASK | BPF_T_FLAG_MASK)) == 0))
   
   #define BPF_T_MICROTIME_FAST            (BPF_T_MICROTIME | BPF_T_FAST)
   #define BPF_T_NANOTIME_FAST             (BPF_T_NANOTIME | BPF_T_FAST)
   #define BPF_T_BINTIME_FAST              (BPF_T_BINTIME | BPF_T_FAST)
   #define BPF_T_MICROTIME_MONOTONIC       (BPF_T_MICROTIME | BPF_T_MONOTONIC)
   #define BPF_T_NANOTIME_MONOTONIC        (BPF_T_NANOTIME | BPF_T_MONOTONIC)
   #define BPF_T_BINTIME_MONOTONIC         (BPF_T_BINTIME | BPF_T_MONOTONIC)
   #define BPF_T_MICROTIME_MONOTONIC_FAST  (BPF_T_MICROTIME | BPF_T_MONOTONIC_FAST)
   #define BPF_T_NANOTIME_MONOTONIC_FAST   (BPF_T_NANOTIME | BPF_T_MONOTONIC_FAST)
   #define BPF_T_BINTIME_MONOTONIC_FAST    (BPF_T_BINTIME | BPF_T_MONOTONIC_FAST)
   
   /*
    * Structure prepended to each packet.
    */
   struct bpf_ts {
           bpf_int64       bt_sec;         /* seconds */
           bpf_u_int64     bt_frac;        /* fraction */
   };
   struct bpf_xhdr {
           struct bpf_ts   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) */
   };
   /* Obsolete */
   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) */
   };
   #ifdef _KERNEL
   #define MTAG_BPF                0x627066
   #define MTAG_BPF_TIMESTAMP      0
   #endif
   
   /*
    * When using zero-copy BPF buffers, a shared memory header is present
    * allowing the kernel BPF implementation and user process to synchronize
    * without using system calls.  This structure defines that header.  When
    * accessing these fields, appropriate atomic operation and memory barriers
    * are required in order not to see stale or out-of-order data; see bpf(4)
    * for reference code to access these fields from userspace.
    *
    * The layout of this structure is critical, and must not be changed; if must
    * fit in a single page on all architectures.
    */
   struct bpf_zbuf_header {
           volatile u_int  bzh_kernel_gen; /* Kernel generation number. */
           volatile u_int  bzh_kernel_len; /* Length of data in the buffer. */
           volatile u_int  bzh_user_gen;   /* User generation number. */
           u_int _bzh_pad[5];
   };
   
   /* Pull in data-link level type codes. */
   #include <net/dlt.h>
   
   /*
    * The instruction encodings.
    *
    * Please inform tcpdump-workers@lists.tcpdump.org if you use any
    * of the reserved values, so that we can note that they're used
    * (and perhaps implement it in the reference BPF implementation
    * and encourage its implementation elsewhere).
    */
   
   /*
    * The upper 8 bits of the opcode aren't used. BSD/OS used 0x8000.
    */
   
   /* 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
   /*                              0x18    reserved; used by BSD/OS */
   #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
   /*                              0xc0    reserved; used by BSD/OS */
   /*                              0xe0    reserved; used by BSD/OS */
   
   /* 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_MOD         0x90
   #define         BPF_XOR         0xa0
   /*                              0xb0    reserved */
   /*                              0xc0    reserved */
   /*                              0xd0    reserved */
   /*                              0xe0    reserved */
   /*                              0xf0    reserved */
   
   #define         BPF_JA          0x00
   #define         BPF_JEQ         0x10
   #define         BPF_JGT         0x20
   #define         BPF_JGE         0x30
   #define         BPF_JSET        0x40
   /*                              0x50    reserved; used on BSD/OS */
   /*                              0x60    reserved */
   /*                              0x70    reserved */
   /*                              0x80    reserved */
   /*                              0x90    reserved */
   /*                              0xa0    reserved */
   /*                              0xb0    reserved */
   /*                              0xc0    reserved */
   /*                              0xd0    reserved */
   /*                              0xe0    reserved */
   /*                              0xf0    reserved */
   #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
   /*                              0x18    reserved */
   
   /* misc */
   #define BPF_MISCOP(code) ((code) & 0xf8)
   #define         BPF_TAX         0x00
   /*                              0x08    reserved */
   /*                              0x10    reserved */
   /*                              0x18    reserved */
   /* #define      BPF_COP         0x20    NetBSD "coprocessor" extensions */
   /*                              0x28    reserved */
   /*                              0x30    reserved */
   /*                              0x38    reserved */
   /* #define      BPF_COPX        0x40    NetBSD "coprocessor" extensions */
   /*                                      also used on BSD/OS */
   /*                              0x48    reserved */
   /*                              0x50    reserved */
   /*                              0x58    reserved */
   /*                              0x60    reserved */
   /*                              0x68    reserved */
   /*                              0x70    reserved */
   /*                              0x78    reserved */
   #define         BPF_TXA         0x80
   /*                              0x88    reserved */
   /*                              0x90    reserved */
   /*                              0x98    reserved */
   /*                              0xa0    reserved */
   /*                              0xa8    reserved */
   /*                              0xb0    reserved */
   /*                              0xb8    reserved */
   /*                              0xc0    reserved; used on BSD/OS */
   /*                              0xc8    reserved */
   /*                              0xd0    reserved */
   /*                              0xd8    reserved */
   /*                              0xe0    reserved */
   /*                              0xe8    reserved */
   /*                              0xf0    reserved */
   /*                              0xf8    reserved */
   
   /*
    * 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 }
   
   /*
    * Structure to retrieve available DLTs for the interface.
    */
   struct bpf_dltlist {
           u_int   bfl_len;        /* number of bfd_list array */
           u_int   *bfl_list;      /* array of DLTs */
   };
   
   #ifdef _KERNEL
   #ifdef MALLOC_DECLARE
   MALLOC_DECLARE(M_BPF);
   #endif
   #ifdef SYSCTL_DECL
   SYSCTL_DECL(_net_bpf);
   #endif
   
   /*
    * Rotate the packet buffers in descriptor d.  Move the store buffer into the
    * hold slot, and the free buffer into the store slot.  Zero the length of the
    * new store buffer.  Descriptor lock should be held.  One must be careful to
    * not rotate the buffers twice, i.e. if fbuf != NULL.
    */
   #define ROTATE_BUFFERS(d)       do {                                    \
           (d)->bd_hbuf = (d)->bd_sbuf;                                    \
           (d)->bd_hlen = (d)->bd_slen;                                    \
           (d)->bd_sbuf = (d)->bd_fbuf;                                    \
           (d)->bd_slen = 0;                                               \
           (d)->bd_fbuf = NULL;                                            \
           bpf_bufheld(d);                                                 \
   } while (0)
   
   /*
    * Descriptor associated with each attached hardware interface.
    * Part of this structure is exposed to external callers to speed up
    * bpf_peers_present() calls.
    */
   struct bpf_if;
   
   struct bpf_if_ext {
           LIST_ENTRY(bpf_if)      bif_next;       /* list of all interfaces */
           LIST_HEAD(, bpf_d)      bif_dlist;      /* descriptor list */
   };
   
   void     bpf_bufheld(struct bpf_d *d);
   int      bpf_validate(const struct bpf_insn *, int);
   void     bpf_tap(struct bpf_if *, u_char *, u_int);
   void     bpf_mtap(struct bpf_if *, struct mbuf *);
   void     bpf_mtap2(struct bpf_if *, void *, u_int, struct mbuf *);
   void     bpfattach(struct ifnet *, u_int, u_int);
   void     bpfattach2(struct ifnet *, u_int, u_int, struct bpf_if **);
   void     bpfdetach(struct ifnet *);
   #ifdef VIMAGE
   int      bpf_get_bp_params(struct bpf_if *, u_int *, u_int *);
   #endif
   
   void     bpfilterattach(int);
   u_int    bpf_filter(const struct bpf_insn *, u_char *, u_int, u_int);
   
   static __inline int
   bpf_peers_present(struct bpf_if *bpf)
   {
           struct bpf_if_ext *ext;
   
           ext = (struct bpf_if_ext *)bpf;
           if (!LIST_EMPTY(&ext->bif_dlist))
                   return (1);
           return (0);
   }
   
   #define BPF_TAP(_ifp,_pkt,_pktlen) do {                         \
           if (bpf_peers_present((_ifp)->if_bpf))                  \
                   bpf_tap((_ifp)->if_bpf, (_pkt), (_pktlen));     \
   } while (0)
   #define BPF_MTAP(_ifp,_m) do {                                  \
           if (bpf_peers_present((_ifp)->if_bpf)) {                \
                   M_ASSERTVALID(_m);                              \
                   bpf_mtap((_ifp)->if_bpf, (_m));                 \
           }                                                       \
   } while (0)
   #define BPF_MTAP2(_ifp,_data,_dlen,_m) do {                     \
           if (bpf_peers_present((_ifp)->if_bpf)) {                \
                   M_ASSERTVALID(_m);                              \
                   bpf_mtap2((_ifp)->if_bpf,(_data),(_dlen),(_m)); \
           }                                                       \
   } while (0)
   #endif
   
   /*
    * Number of scratch memory words (for BPF_LD|BPF_MEM and BPF_ST).
    */
   #define BPF_MEMWORDS 16
   
   #ifdef _SYS_EVENTHANDLER_H_
   /* BPF attach/detach events */
   struct ifnet;
   typedef void (*bpf_track_fn)(void *, struct ifnet *, int /* dlt */,
       int /* 1 =>'s attach */);
   EVENTHANDLER_DECLARE(bpf_track, bpf_track_fn);
   #endif /* _SYS_EVENTHANDLER_H_ */
   
   #endif /* _NET_BPF_H_ */

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