mbuf.h

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//==========================================================================
//
//      include/sys/mbuf.h
//
//==========================================================================
//####BSDCOPYRIGHTBEGIN####
//
// -------------------------------------------
//
// Portions of this software may have been derived from OpenBSD, 
// FreeBSD or other sources, and are covered by the appropriate
// copyright disclaimers included herein.
//
// Portions created by Red Hat are
// Copyright (C) 2002 Red Hat, Inc. All Rights Reserved.
//
// -------------------------------------------
//
//####BSDCOPYRIGHTEND####
//==========================================================================

/*
 * Copyright (c) 1982, 1986, 1988, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * 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.
 *
 *	@(#)mbuf.h	8.5 (Berkeley) 2/19/95
 * $FreeBSD: src/sys/sys/mbuf.h,v 1.44.2.10 2001/07/03 11:02:01 ume Exp $
 */

#ifndef _SYS_MBUF_H_
#define	_SYS_MBUF_H_

/*
 * Mbufs are of a single size, MSIZE (machine/param.h), which
 * includes overhead.  An mbuf may add a single "mbuf cluster" of size
 * MCLBYTES (also in machine/param.h), which has no additional overhead
 * and is used instead of the internal data area; this is done when
 * at least MINCLSIZE of data must be stored.
 */

#define	MLEN		(MSIZE - sizeof(struct m_hdr))	/* normal data len */
#define	MHLEN		(MLEN - sizeof(struct pkthdr))	/* data len w/pkthdr */

#define	MINCLSIZE	(MHLEN + 1)	/* smallest amount to put in cluster */
#define	M_MAXCOMPRESS	(MHLEN / 2)	/* max amount to copy for compression */

/*
 * Macros for type conversion
 * mtod(m, t) -	convert mbuf pointer to data pointer of correct type
 * dtom(x) -	convert data pointer within mbuf to mbuf pointer (XXX)
 * mtocl(x) -	convert pointer within cluster to cluster index #
 * cltom(x) -	convert cluster # to ptr to beginning of cluster
 */
#define	mtod(m, t)	((t)((m)->m_data))
#define	dtom(x)		((struct mbuf *)((CYG_ADDRESS)(x) & ~(MSIZE-1)))
extern int cyg_mtocl(u_long);
extern struct mbuf *cyg_cltom(u_long);
#define mtocl(x) cyg_mtocl((u_long)x)
#define cltom(x) cyg_cltom((u_long)x)

/* header at beginning of each mbuf: */
struct m_hdr {
	struct	mbuf *mh_next;		/* next buffer in chain */
	struct	mbuf *mh_nextpkt;	/* next chain in queue/record */
	caddr_t	mh_data;		/* location of data */
	int	mh_len;			/* amount of data in this mbuf */
	short	mh_type;		/* type of data in this mbuf */
	short	mh_flags;		/* flags; see below */
};

/* record/packet header in first mbuf of chain; valid if M_PKTHDR set */
struct pkthdr {
	struct	ifnet *rcvif;		/* rcv interface */
	int	len;			/* total packet length */
	/* variables for ip and tcp reassembly */
	void	*header;		/* pointer to packet header */
	/* variables for hardware checksum */
	int	csum_flags;		/* flags regarding checksum */
	int	csum_data;		/* data field used by csum routines */
	struct	mbuf *aux;		/* extra data buffer; ipsec/others */
};

/* description of external storage mapped into mbuf, valid if M_EXT set */
struct m_ext {
	caddr_t	ext_buf;		/* start of buffer */
	void	(*ext_free)		/* free routine if not the usual */
		__P((caddr_t, u_int));
	u_int	ext_size;		/* size of buffer, for ext_free */
	void	(*ext_ref)		/* add a reference to the ext object */
		__P((caddr_t, u_int));
};

struct mbuf {
	struct	m_hdr m_hdr;
	union {
		struct {
			struct	pkthdr MH_pkthdr;	/* M_PKTHDR set */
			union {
				struct	m_ext MH_ext;	/* M_EXT set */
				char	MH_databuf[MHLEN];
			} MH_dat;
		} MH;
		char	M_databuf[MLEN];		/* !M_PKTHDR, !M_EXT */
	} M_dat;
};
#define	m_next		m_hdr.mh_next
#define	m_len		m_hdr.mh_len
#define	m_data		m_hdr.mh_data
#define	m_type		m_hdr.mh_type
#define	m_flags		m_hdr.mh_flags
#define	m_nextpkt	m_hdr.mh_nextpkt
#define	m_act		m_nextpkt
#define	m_pkthdr	M_dat.MH.MH_pkthdr
#define	m_ext		M_dat.MH.MH_dat.MH_ext
#define	m_pktdat	M_dat.MH.MH_dat.MH_databuf
#define	m_dat		M_dat.M_databuf

/* mbuf flags */
#define	M_EXT		0x0001	/* has associated external storage */
#define	M_PKTHDR	0x0002	/* start of record */
#define	M_EOR		0x0004	/* end of record */
#define	M_PROTO1	0x0008	/* protocol-specific */
#define	M_PROTO2	0x0010	/* protocol-specific */
#define	M_PROTO3	0x0020	/* protocol-specific */
#define	M_PROTO4	0x0040	/* protocol-specific */
#define	M_PROTO5	0x0080	/* protocol-specific */
#define	M_PROTO6	0x2000	/* protocol-specific */

/* mbuf pkthdr flags, also in m_flags */
#define	M_BCAST		0x0100	/* send/received as link-level broadcast */
#define	M_MCAST		0x0200	/* send/received as link-level multicast */
#define	M_FRAG		0x0400	/* packet is a fragment of a larger packet */
#define	M_FIRSTFRAG	0x0800	/* packet is first fragment */
#define	M_LASTFRAG	0x1000	/* packet is last fragment */

#define M_AUX		0x4000	/* mbufs pointed to by m->m_pkthdr.aux */

/* flags copied when copying m_pkthdr */
#define	M_COPYFLAGS	(M_PKTHDR|M_EOR|M_PROTO1|M_PROTO1|M_PROTO2|M_PROTO3| \
			    M_PROTO4|M_PROTO5|M_PROTO6|M_BCAST|M_MCAST|M_FRAG| \
			    M_AUX)

/* flags indicating hw checksum support and sw checksum requirements */
#define CSUM_IP			0x0001		/* will csum IP */
#define CSUM_TCP		0x0002		/* will csum TCP */
#define CSUM_UDP		0x0004		/* will csum UDP */
#define CSUM_IP_FRAGS		0x0008		/* will csum IP fragments */
#define CSUM_FRAGMENT		0x0010		/* will do IP fragmentation */

#define CSUM_IP_CHECKED		0x0100		/* did csum IP */
#define CSUM_IP_VALID		0x0200		/*   ... the csum is valid */
#define CSUM_DATA_VALID		0x0400		/* csum_data field is valid */
#define CSUM_PSEUDO_HDR		0x0800		/* csum_data has pseudo hdr */

#define CSUM_DELAY_DATA		(CSUM_TCP | CSUM_UDP)
#define CSUM_DELAY_IP		(CSUM_IP)	/* XXX add ipv6 here too? */

/* mbuf types */
#define	MT_FREE		0	/* should be on free list */
#define	MT_DATA		1	/* dynamic (data) allocation */
#define	MT_HEADER	2	/* packet header */
#if 0
#define	MT_SOCKET	3	/* socket structure */
#define	MT_PCB		4	/* protocol control block */
#define	MT_RTABLE	5	/* routing tables */
#define	MT_HTABLE	6	/* IMP host tables */
#define	MT_ATABLE	7	/* address resolution tables */
#endif
#define	MT_SONAME	8	/* socket name */
#if 0
#define	MT_SOOPTS	10	/* socket options */
#endif
#define	MT_FTABLE	11	/* fragment reassembly header */
#if 0
#define	MT_RIGHTS	12	/* access rights */
#define	MT_IFADDR	13	/* interface address */
#endif
#define	MT_CONTROL	14	/* extra-data protocol message */
#define	MT_OOBDATA	15	/* expedited data  */

#define	MT_NTYPES	16	/* number of mbuf types for mbtypes[] */

/*
 * mbuf statistics
 */
struct mbstat {
	u_long	m_mbufs;	/* mbufs obtained from page pool */
	u_long	m_clusters;	/* clusters obtained from page pool */
	u_long	m_spare;	/* spare field */
	u_long	m_clfree;	/* free clusters */
	u_long	m_drops;	/* times failed to find space */
	u_long	m_wait;		/* times waited for space */
	u_long	m_drain;	/* times drained protocols for space */
	u_long	m_mcfail;	/* times m_copym failed */
	u_long	m_mpfail;	/* times m_pullup failed */
	u_long	m_msize;	/* length of an mbuf */
	u_long	m_mclbytes;	/* length of an mbuf cluster */
	u_long	m_minclsize;	/* min length of data to allocate a cluster */
	u_long	m_mlen;		/* length of data in an mbuf */
	u_long	m_mhlen;	/* length of data in a header mbuf */

	u_quad_t m_exthdrget;	/* # of calls to IP6_EXTHDR_GET */
	u_quad_t m_exthdrget0;	/* # of calls to IP6_EXTHDR_GET0 */
	u_quad_t m_pulldowns;	/* # of calls to m_pulldown */
	u_quad_t m_pulldown_copy; /* # of mbuf copies in m_pulldown */
	u_quad_t m_pulldown_alloc; /* # of mbuf allocs in m_pulldown */
	u_quad_t m_pullups;	/* # of calls to m_pullup */
	u_quad_t m_pullup_copy;	/* # of possible m_pullup copies */
	u_quad_t m_pullup_alloc; /* # of possible m_pullup mallocs */
	u_quad_t m_pullup_fail;	/* # of possible m_pullup failures */
	u_quad_t m_pullup2;	/* # of calls to m_pullup2 */
	u_quad_t m_pullup2_copy; /* # of possible m_pullup2 copies */
	u_quad_t m_pullup2_alloc; /* # of possible m_pullup2 mallocs */
	u_quad_t m_pullup2_fail; /* # of possible m_pullup2 failures */
};

/* flags to m_get/MGET */
#define	M_DONTWAIT	1
#define	M_WAIT		0

/* Freelists:
 *
 * Normal mbuf clusters are normally treated as character arrays
 * after allocation, but use the first word of the buffer as a free list
 * pointer while on the free list.
 */
union mcluster {
	union	mcluster *mcl_next;
	char	mcl_buf[MCLBYTES];
};


/*
 * These are identifying numbers passed to the m_mballoc_wait function,
 * allowing us to determine whether the call came from an MGETHDR or
 * an MGET.
 */
#define	MGETHDR_C      1
#define	MGET_C         2

/*
 * Wake up the next instance (if any) of m_mballoc_wait() which is
 * waiting for an mbuf to be freed.  This should be called at splimp().
 *
 * XXX: If there is another free mbuf, this routine will be called [again]
 * from the m_mballoc_wait routine in order to wake another sleep instance.
 */
#define	MMBWAKEUP() do {						\
	if (m_mballoc_wid) {						\
		m_mballoc_wid--;					\
		wakeup_one(&m_mballoc_wid); 				\
	}								\
} while (0)

/*
 * Same as above, but for mbuf cluster(s).
 */
#define	MCLWAKEUP() do {						\
	if (m_clalloc_wid) {						\
		m_clalloc_wid--;					\
		wakeup_one(&m_clalloc_wid);				\
	}								\
} while (0)

/*
 * mbuf utility macros:
 *
 *	MBUFLOCK(code)
 * prevents a section of code from from being interrupted by network
 * drivers.
 */
#define	MBUFLOCK(code) do {						\
	int _ms = splimp();						\
									\
	{ code }							\
	splx(_ms);							\
} while (0)

/*
 * mbuf allocation/deallocation macros:
 *
 *	MGET(struct mbuf *m, int how, int type)
 * allocates an mbuf and initializes it to contain internal data.
 *
 *	MGETHDR(struct mbuf *m, int how, int type)
 * allocates an mbuf and initializes it to contain a packet header
 * and internal data.
 */
#define	MGET(m, how, type) do {						\
	struct mbuf *_mm;						\
	int _mhow = (how);						\
	int _mtype = (type);						\
	int _ms = splimp();						\