xref: /src/sys/net/bpf.h

/*	$NetBSD: bpf.h,v 1.64 2014/06/24 10:53:30 alnsn Exp $	*/

/*
 * 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	8.2 (Berkeley) 1/9/95
 * @(#) Header: bpf.h,v 1.36 97/06/12 14:29:53 leres Exp  (LBL)
 */

#ifndef _NET_BPF_H_
#define _NET_BPF_H_

#include <sys/time.h>

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

/* Date when COP instructions and external memory have been released. */
#define BPF_COP_EXTMEM_RELEASE 20140624

__BEGIN_DECLS

typedef	int bpf_int32;
typedef	u_int bpf_u_int32;

/*
 * Alignment macros.  BPF_WORDALIGN rounds up to the next
 * even multiple of BPF_ALIGNMENT.
 */
#define BPF_ALIGNMENT sizeof(long)
#define BPF_ALIGNMENT32 sizeof(int)

#define BPF_WORDALIGN(x) (((x)+(BPF_ALIGNMENT-1))&~(BPF_ALIGNMENT-1))
#define BPF_WORDALIGN32(x) (((x)+(BPF_ALIGNMENT32-1))&~(BPF_ALIGNMENT32-1))

#define BPF_MAXINSNS 512
#define BPF_DFLTBUFSIZE (1024*1024)	/* default static upper limit */
#define BPF_MAXBUFSIZE (1024*1024*16)	/* hard limit on sysctl'able value */
#define BPF_MINBUFSIZE 32

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

/*
 * Struct returned by BIOCGSTATS and net.bpf.stats sysctl.
 */
struct bpf_stat {
	uint64_t bs_recv;	/* number of packets received */
	uint64_t bs_drop;	/* number of packets dropped */
	uint64_t bs_capt;	/* number of packets captured */
	uint64_t bs_padding[13];
};

/*
 * Struct returned by BIOCGSTATSOLD.
 */
struct bpf_stat_old {
	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

/*
 * BPF ioctls
 *
 * The first set is for compatibility with Sun's pcc style
 * header files.  If your using gcc, we assume that you
 * have run fixincludes so the latter set should work.
 */
#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)
#ifdef COMPAT_50
#include <compat/sys/time.h>
#define BIOCSORTIMEOUT	 _IOW('B',109, struct timeval50)
#define BIOCGORTIMEOUT	 _IOR('B',110, struct timeval50)
#endif
#define BIOCGSTATS	 _IOR('B',111, struct bpf_stat)
#define BIOCGSTATSOLD	 _IOR('B',111, struct bpf_stat_old)
#define BIOCIMMEDIATE	 _IOW('B',112, u_int)
#define BIOCVERSION	 _IOR('B',113, struct bpf_version)
#define BIOCSTCPF	 _IOW('B',114, struct bpf_program)
#define BIOCSUDPF	 _IOW('B',115, struct bpf_program)
#define BIOCGHDRCMPLT	 _IOR('B',116, u_int)
#define BIOCSHDRCMPLT	 _IOW('B',117, u_int)
#define BIOCSDLT	 _IOW('B',118, u_int)
#define BIOCGDLTLIST	_IOWR('B',119, struct bpf_dltlist)
#define BIOCGSEESENT	 _IOR('B',120, u_int)
#define BIOCSSEESENT	 _IOW('B',121, u_int)
#define BIOCSRTIMEOUT	 _IOW('B',122, struct timeval)
#define BIOCGRTIMEOUT	 _IOR('B',123, struct timeval)
#define BIOCGFEEDBACK	 _IOR('B',124, u_int)
#define BIOCSFEEDBACK	 _IOW('B',125, u_int)
#define BIOCFEEDBACK     BIOCSFEEDBACK		/* FreeBSD name */

/*
 * Structure prepended to each packet. This is "wire" format, so we
 * cannot change it unfortunately to 64 bit times on 32 bit systems [yet].
 */
struct bpf_timeval {
	long tv_sec;
	long tv_usec;
};

struct bpf_timeval32 {
	int32_t tv_sec;
	int32_t tv_usec;
};

struct bpf_hdr {
	struct bpf_timeval bh_tstamp;	/* time stamp */
	uint32_t	bh_caplen;	/* length of captured portion */
	uint32_t	bh_datalen;	/* original length of packet */
	uint16_t	bh_hdrlen;	/* length of bpf header (this struct
					   plus alignment padding) */
};

struct bpf_hdr32 {
	struct bpf_timeval32 bh_tstamp;	/* time stamp */
	uint32_t	bh_caplen;	/* length of captured portion */
	uint32_t	bh_datalen;	/* original length of packet */
	uint16_t	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.
 * XXX To save a few bytes on 32-bit machines, we avoid end-of-struct
 * XXX padding by using the size of the header data elements.  This is
 * XXX fail-safe: on new machines, we just use the 'safe' sizeof.
 */
#ifdef _KERNEL
#if defined(__arm32__) || defined(__i386__) || defined(__m68k__) || \
    defined(__mips__) || defined(__ns32k__) || defined(__vax__) || \
    defined(__sh__) || (defined(__sparc__) && !defined(__sparc64__))
#define SIZEOF_BPF_HDR 18
#define SIZEOF_BPF_HDR32 18
#else
#define SIZEOF_BPF_HDR sizeof(struct bpf_hdr)
#define SIZEOF_BPF_HDR32 sizeof(struct bpf_hdr32)
#endif
#endif

/* Pull in data-link level type codes. */
#include <net/dlt.h>

/*
 * 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_COP		0x20
#define		BPF_COPX	0x40
#define		BPF_TXA		0x80

/*
 * The instruction data structure.
 */
struct bpf_insn {
	uint16_t  code;
	u_char 	  jt;
	u_char 	  jf;
	uint32_t  k;
};

/*
 * Macros for insn array initializers.
 */
#define BPF_STMT(code, k) { (uint16_t)(code), 0, 0, k }
#define BPF_JUMP(code, k, jt, jf) { (uint16_t)(code), jt, jf, k }

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

/*
 * Each bit in bpf_memword_init_t value indicates if the corresponding
 * external memory word is initialised prior to calling a bpf program.
 * Note that when used internally, a meaning is often flipped: bits
 * indicate which memory words need to be initialised prior to
 * executing a bpf program.
 */
typedef uint32_t bpf_memword_init_t;
#define BPF_MEMWORD_INIT(k) (UINT32_C(1) << (k))

/* Two most significant bits are reserved by bpfjit. */
__CTASSERT(BPF_MEMWORDS + 2 <= sizeof(bpf_memword_init_t) * NBBY);

#ifdef _KERNEL
/*
 * Max number of external memory words (for BPF_LD|BPF_MEM and BPF_ST).
 */
#define	BPF_MAX_MEMWORDS	30
__CTASSERT(BPF_MAX_MEMWORDS >= BPF_MEMWORDS);

#ifdef __BPF_PRIVATE
/* Two most significant bits are reserved by bpfjit. */
__CTASSERT(BPF_MAX_MEMWORDS + 2 <= sizeof(bpf_memword_init_t) * NBBY);
#endif
#endif

/*
 * 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 */
};

struct bpf_ctx;
typedef struct bpf_ctx bpf_ctx_t;

struct bpf_args;
typedef struct bpf_args bpf_args_t;

struct bpf_args {
	const uint8_t *	pkt;
	size_t		wirelen;
	size_t		buflen;
	/*
	 * The following arguments are used only by some kernel
	 * subsystems.
	 * They aren't required for classical bpf filter programs.
	 * For such programs, bpfjit generated code doesn't read
	 * those arguments at all. Note however that bpf interpreter
	 * always needs a pointer to memstore.
	 */
	uint32_t *	mem; /* pointer to external memory store */
	void *		arg; /* auxiliary argument for a copfunc */
};

#if defined(_KERNEL) || defined(__BPF_PRIVATE)
typedef uint32_t (*bpf_copfunc_t)(const bpf_ctx_t *, bpf_args_t *, uint32_t);

struct bpf_ctx {
	const bpf_copfunc_t *	copfuncs;
	size_t			nfuncs;
	/*
	 * Number of external memwords, up to BPF_MAX_MEMWORDS or 0.
	 * The latter forces a switch to internal memstore with a
	 * fixed number (BPF_MEMWORDS) of memwords.
	 */
	size_t			extwords;
	bpf_memword_init_t	noinit; /* pre-initialised external memwords */
};
#endif

#ifdef _KERNEL
#include <net/bpfjit.h>
#include <net/if.h>

struct bpf_if;

struct bpf_ops {
	void (*bpf_attach)(struct ifnet *, u_int, u_int, struct bpf_if **);
	void (*bpf_detach)(struct ifnet *);
	void (*bpf_change_type)(struct ifnet *, u_int, u_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 (*bpf_mtap_af)(struct bpf_if *, uint32_t, struct mbuf *);
	void (*bpf_mtap_sl_in)(struct bpf_if *, u_char *, struct mbuf **);
	void (*bpf_mtap_sl_out)(struct bpf_if *, u_char *, struct mbuf *);
};

extern struct bpf_ops *bpf_ops;

static inline void
bpf_attach(struct ifnet *_ifp, u_int _dlt, u_int _hdrlen)
{
	bpf_ops->bpf_attach(_ifp, _dlt, _hdrlen, &_ifp->if_bpf);
}

static inline void
bpf_attach2(struct ifnet *_ifp, u_int _dlt, u_int _hdrlen, struct bpf_if **_dp)
{
	bpf_ops->bpf_attach(_ifp, _dlt, _hdrlen, _dp);
}

static inline void
bpf_tap(struct ifnet *_ifp, u_char *_pkt, u_int _len)
{
	if (_ifp->if_bpf)
		bpf_ops->bpf_tap(_ifp->if_bpf, _pkt, _len);
}

static inline void
bpf_mtap(struct ifnet *_ifp, struct mbuf *_m)
{
	if (_ifp->if_bpf)
		bpf_ops->bpf_mtap(_ifp->if_bpf, _m);
}

static inline void
bpf_mtap2(struct bpf_if *_bpf, void *_data, u_int _dlen, struct mbuf *_m)
{
	bpf_ops->bpf_mtap2(_bpf, _data, _dlen, _m);
}

static inline void
bpf_mtap3(struct bpf_if *_bpf, struct mbuf *_m)
{
	if (_bpf)
		bpf_ops->bpf_mtap(_bpf, _m);
}

static inline void
bpf_mtap_af(struct ifnet *_ifp, uint32_t _af, struct mbuf *_m)
{
	if (_ifp->if_bpf)
		bpf_ops->bpf_mtap_af(_ifp->if_bpf, _af, _m);
}

static inline void
bpf_change_type(struct ifnet *_ifp, u_int _dlt, u_int _hdrlen)
{
	bpf_ops->bpf_change_type(_ifp, _dlt, _hdrlen);
}

static inline void
bpf_detach(struct ifnet *_ifp)
{
	bpf_ops->bpf_detach(_ifp);
}

static inline void
bpf_mtap_sl_in(struct ifnet *_ifp, u_char *_hdr, struct mbuf **_m)
{
	bpf_ops->bpf_mtap_sl_in(_ifp->if_bpf, _hdr, _m);
}

static inline void
bpf_mtap_sl_out(struct ifnet *_ifp, u_char *_hdr, struct mbuf *_m)
{
	if (_ifp->if_bpf)
		bpf_ops->bpf_mtap_sl_out(_ifp->if_bpf, _hdr, _m);
}


void     bpf_setops(void);

void     bpf_ops_handover_enter(struct bpf_ops *);
void     bpf_ops_handover_exit(void);

void	 bpfilterattach(int);

bpf_ctx_t *bpf_create(void);
void	bpf_destroy(bpf_ctx_t *);

int   bpf_set_cop(bpf_ctx_t *, const bpf_copfunc_t *, size_t);
int   bpf_set_extmem(bpf_ctx_t *, size_t, bpf_memword_init_t);
u_int bpf_filter_ext(const bpf_ctx_t *, const struct bpf_insn *, bpf_args_t *);
int   bpf_validate_ext(const bpf_ctx_t *, const struct bpf_insn *, int);

bpfjit_func_t bpf_jit_generate(bpf_ctx_t *, void *, size_t);
void	bpf_jit_freecode(bpfjit_func_t);

#endif

int	bpf_validate(const struct bpf_insn *, int);
u_int	bpf_filter(const struct bpf_insn *, const u_char *, u_int, u_int);

__END_DECLS

#endif /* !_NET_BPF_H_ */