/*	$NetBSD: mbuf.h,v 1.155 2014/05/17 23:27:59 rmind Exp $	*/

/*-
 * Copyright (c) 1996, 1997, 1999, 2001, 2007 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
 * NASA Ames Research Center and Matt Thomas of 3am Software Foundry.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */

/*
 * 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. 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
 */

#ifndef _SYS_MBUF_H_
#define _SYS_MBUF_H_

#ifdef _KERNEL_OPT
#include "opt_mbuftrace.h"
#endif

#ifndef M_WAITOK
#include <sys/malloc.h>
#endif
#include <sys/pool.h>
#include <sys/queue.h>
#if defined(_KERNEL)
#include <sys/percpu_types.h>
#endif /* defined(_KERNEL) */

/* For offsetof() */
#if defined(_KERNEL) || defined(_STANDALONE)
#include <sys/systm.h>
#else
#include <stddef.h>
#endif

#include <uvm/uvm_param.h>	/* for MIN_PAGE_SIZE */

/*
 * 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.
 */

/* Packet tags structure */
struct m_tag {
	SLIST_ENTRY(m_tag)	m_tag_link;	/* List of packet tags */
	uint16_t		m_tag_id;	/* Tag ID */
	uint16_t		m_tag_len;	/* Length of data */
};

/* mbuf ownership structure */
struct mowner {
	char mo_name[16];		/* owner name (fxp0) */
	char mo_descr[16];		/* owner description (input) */
	LIST_ENTRY(mowner) mo_link;	/* */
	struct percpu *mo_counters;
};

#define MOWNER_INIT(x, y) { .mo_name = x, .mo_descr = y }

enum mowner_counter_index {
	MOWNER_COUNTER_CLAIMS,		/* # of small mbuf claimed */
	MOWNER_COUNTER_RELEASES,	/* # of small mbuf released */
	MOWNER_COUNTER_CLUSTER_CLAIMS,	/* # of M_CLUSTER mbuf claimed */
	MOWNER_COUNTER_CLUSTER_RELEASES,/* # of M_CLUSTER mbuf released */
	MOWNER_COUNTER_EXT_CLAIMS,	/* # of M_EXT mbuf claimed */
	MOWNER_COUNTER_EXT_RELEASES,	/* # of M_EXT mbuf released */

	MOWNER_COUNTER_NCOUNTERS,
};

#if defined(_KERNEL)
struct mowner_counter {
	u_long mc_counter[MOWNER_COUNTER_NCOUNTERS];
};
#endif /* defined(_KERNEL) */

/* userland-exported version of struct mowner */
struct mowner_user {
	char mo_name[16];		/* owner name (fxp0) */
	char mo_descr[16];		/* owner description (input) */
	LIST_ENTRY(mowner) mo_link;	/* unused padding; for compatibility */
	u_long mo_counter[MOWNER_COUNTER_NCOUNTERS]; /* counters */
};

/*
 * Macros for type conversion
 * mtod(m,t) -	convert mbuf pointer to data pointer of correct type
 */
#define	mtod(m, t)	((t)((m)->m_data))

/* 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 */
	char   *mh_data;		/* location of data */
	struct	mowner *mh_owner;	/* mbuf owner */
	int	mh_len;			/* amount of data in this mbuf */
	int	mh_flags;		/* flags; see below */
	paddr_t	mh_paddr;		/* physical address of mbuf */
	short	mh_type;		/* type of data in this mbuf */
};

/*
 * record/packet header in first mbuf of chain; valid if M_PKTHDR set
 *
 * A note about csum_data: For the out-bound direction, the low 16 bits
 * indicates the offset after the L4 header where the final L4 checksum value
 * is to be stored and the high 16 bits is the length of the L3 header (the
 * start of the data to be checksumed).  For the in-bound direction, it is only
 * valid if the M_CSUM_DATA flag is set.  In this case, an L4 checksum has been
 * calculated by hardware, but it is up to software to perform final
 * verification.
 *
 * Note for in-bound TCP/UDP checksums, we expect the csum_data to NOT
 * be bit-wise inverted (the final step in the calculation of an IP
 * checksum) -- this is so we can accumulate the checksum for fragmented
 * packets during reassembly.
 */
struct	pkthdr {
	struct ifnet	*rcvif;			/* rcv interface */
	SLIST_HEAD(packet_tags, m_tag) tags;	/* list of packet tags */
	int		len;			/* total packet length */
	int		csum_flags;		/* checksum flags */
	uint32_t	csum_data;		/* checksum data */
	u_int		segsz;			/* segment size */
};

/*
 * Note: These bits are carefully arrange so that the compiler can have
 * a prayer of generating a jump table.
 */
#define	M_CSUM_TCPv4		0x00000001	/* TCP header/payload */
#define	M_CSUM_UDPv4		0x00000002	/* UDP header/payload */
#define	M_CSUM_TCP_UDP_BAD	0x00000004	/* TCP/UDP checksum bad */
#define	M_CSUM_DATA		0x00000008	/* consult csum_data */
#define	M_CSUM_TCPv6		0x00000010	/* IPv6 TCP header/payload */
#define	M_CSUM_UDPv6		0x00000020	/* IPv6 UDP header/payload */
#define	M_CSUM_IPv4		0x00000040	/* IPv4 header */
#define	M_CSUM_IPv4_BAD		0x00000080	/* IPv4 header checksum bad */
#define	M_CSUM_TSOv4		0x00000100	/* TCPv4 segmentation offload */
#define	M_CSUM_TSOv6		0x00000200	/* TCPv6 segmentation offload */

/* Checksum-assist quirks: keep separate from jump-table bits. */
#define	M_CSUM_NO_PSEUDOHDR	0x80000000	/* Rx csum_data does not include
						 * the UDP/TCP pseudo-hdr, and
						 * is not yet 1s-complemented.
						 */

#define M_CSUM_BITS \
    "\20\1TCPv4\2UDPv4\3TCP_UDP_BAD\4DATA\5TCPv6\6UDPv6\7IPv4\10IPv4_BAD" \
    "\11TSOv4\12TSOv6\40NO_PSEUDOHDR"

/*
 * Macros for manipulating csum_data on outgoing packets.  These are
 * used to pass information down from the L4/L3 to the L2.
 */
#define	M_CSUM_DATA_IPv4_IPHL(x)	((x) >> 16)
#define	M_CSUM_DATA_IPv4_OFFSET(x)	((x) & 0xffff)

/*
 * Macros for M_CSUM_TCPv6 and M_CSUM_UDPv6
 *
 * M_CSUM_DATA_IPv6_HL: length of ip6_hdr + ext header.
 * ie. offset of UDP/TCP header in the packet.
 *
 * M_CSUM_DATA_IPv6_OFFSET: offset of the checksum field in UDP/TCP header. 
 */

#define	M_CSUM_DATA_IPv6_HL(x)		((x) >> 16)
#define	M_CSUM_DATA_IPv6_HL_SET(x, v)	(x) = ((x) & 0xffff) | ((v) << 16)
#define	M_CSUM_DATA_IPv6_OFFSET(x)	((x) & 0xffff)

/*
 * Max # of pages we can attach to m_ext.  This is carefully chosen
 * to be able to handle SOSEND_LOAN_CHUNK with our minimum sized page.
 */
#ifdef MIN_PAGE_SIZE
#define	M_EXT_MAXPAGES		((65536 / MIN_PAGE_SIZE) + 1)
#endif

/* description of external storage mapped into mbuf, valid if M_EXT set */
struct _m_ext_storage {
	unsigned int ext_refcnt;
	int ext_flags;
	char *ext_buf;			/* start of buffer */
	void (*ext_free)		/* free routine if not the usual */
		(struct mbuf *, void *, size_t, void *);
	void *ext_arg;			/* argument for ext_free */
	size_t ext_size;		/* size of buffer, for ext_free */
	union {
		paddr_t extun_paddr;	/* physical address (M_EXT_CLUSTER) */
					/* pages (M_EXT_PAGES) */
	/*
	 * XXX This is gross, but it doesn't really matter; this is
	 * XXX overlaid on top of the mbuf data area.
	 */
#ifdef M_EXT_MAXPAGES
		struct vm_page *extun_pgs[M_EXT_MAXPAGES];
#endif
	} ext_un;
#define	ext_paddr	ext_un.extun_paddr
#define	ext_pgs		ext_un.extun_pgs
#ifdef DEBUG
	const char *ext_ofile;
	const char *ext_nfile;
	int ext_oline;
	int ext_nline;
#endif
};

struct _m_ext {
	struct mbuf *ext_ref;
	struct _m_ext_storage ext_storage;
};

#define	M_PADDR_INVALID		POOL_PADDR_INVALID

/*
 * Definition of "struct mbuf".
 * Don't change this without understanding how MHLEN/MLEN are defined.
 */
#define	MBUF_DEFINE(name, mhlen, mlen)					\
	struct name {							\
		struct	m_hdr m_hdr;					\
		union {							\
			struct {					\
				struct	pkthdr MH_pkthdr;		\
				union {					\
					struct	_m_ext MH_ext;		\
					char MH_databuf[(mhlen)];	\
				} MH_dat;				\
			} MH;						\
			char M_databuf[(mlen)];				\
		} 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_owner		m_hdr.mh_owner
#define	m_type		m_hdr.mh_type
#define	m_flags		m_hdr.mh_flags
#define	m_nextpkt	m_hdr.mh_nextpkt
#define	m_paddr		m_hdr.mh_paddr
#define	m_pkthdr	M_dat.MH.MH_pkthdr
#define	m_ext_storage	M_dat.MH.MH_dat.MH_ext.ext_storage
#define	m_ext_ref	M_dat.MH.MH_dat.MH_ext.ext_ref
#define	m_ext		m_ext_ref->m_ext_storage
#define	m_pktdat	M_dat.MH.MH_dat.MH_databuf
#define	m_dat		M_dat.M_databuf

/*
 * Dummy mbuf structure to calculate the right values for MLEN/MHLEN, taking
 * into account inter-structure padding.
 */
MBUF_DEFINE(_mbuf_dummy, 1, 1);

/* normal data len */
#define	MLEN		(MSIZE - offsetof(struct _mbuf_dummy, m_dat))
/* data len w/pkthdr */
#define	MHLEN		(MSIZE - offsetof(struct _mbuf_dummy, m_pktdat))

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

/*
 * The *real* struct mbuf
 */
MBUF_DEFINE(mbuf, MHLEN, MLEN);

/* mbuf flags */
#define	M_EXT		0x00001	/* has associated external storage */
#define	M_PKTHDR	0x00002	/* start of record */
#define	M_EOR		0x00004	/* end of record */
#define	M_PROTO1	0x00008	/* protocol-specific */

/* mbuf pkthdr flags, also in m_flags */
#define M_AUTHIPHDR	0x00010	/* data origin authentication for IP header */
#define M_DECRYPTED	0x00020	/* confidentiality */
#define M_LOOP		0x00040	/* for Mbuf statistics */
#define M_AUTHIPDGM     0x00080  /* data origin authentication */
#define	M_BCAST		0x00100	/* send/received as link-level broadcast */
#define	M_MCAST		0x00200	/* send/received as link-level multicast */
#define	M_CANFASTFWD	0x00400	/* used by filters to indicate packet can
				   be fast-forwarded */
#define	M_ANYCAST6	0x00800	/* received as IPv6 anycast */
#define	M_LINK0		0x01000	/* link layer specific flag */
#define	M_LINK1		0x02000	/* link layer specific flag */
#define	M_LINK2		0x04000	/* link layer specific flag */
#define	M_LINK3		0x08000	/* link layer specific flag */
#define	M_LINK4		0x10000	/* link layer specific flag */
#define	M_LINK5		0x20000	/* link layer specific flag */
#define	M_LINK6		0x40000	/* link layer specific flag */
#define	M_LINK7		0x80000	/* link layer specific flag */

/* additional flags for M_EXT mbufs */
#define	M_EXT_FLAGS	0xff000000
#define	M_EXT_CLUSTER	0x01000000	/* ext is a cluster */
#define	M_EXT_PAGES	0x02000000	/* ext_pgs is valid */
#define	M_EXT_ROMAP	0x04000000	/* ext mapping is r-o at MMU */
#define	M_EXT_RW	0x08000000	/* ext storage is writable */

/* for source-level compatibility */
#define	M_CLUSTER	M_EXT_CLUSTER

#define M_FLAGS_BITS \
    "\20\1EXT\2PKTHDR\3EOR\4PROTO1\5AUTHIPHDR\6DECRYPTED\7LOOP\10AUTHIPDGM" \
    "\11BCAST\12MCAST\13CANFASTFWD\14ANYCAST6\15LINK0\16LINK1\17LINK2\20LINK3" \
    "\21LINK4\22LINK5\23LINK6\24LINK7" \
    "\31EXT_CLUSTER\32EXT_PAGES\33EXT_ROMAP\34EXT_RW"

/* flags copied when copying m_pkthdr */
#define	M_COPYFLAGS	(M_PKTHDR|M_EOR|M_BCAST|M_MCAST|M_CANFASTFWD|M_ANYCAST6|M_LINK0|M_LINK1|M_LINK2|M_AUTHIPHDR|M_DECRYPTED|M_LOOP|M_AUTHIPDGM)

/* flag copied when shallow-copying external storage */
#define	M_EXTCOPYFLAGS	(M_EXT|M_EXT_FLAGS)

/* mbuf types */
#define	MT_FREE		0	/* should be on free list */
#define	MT_DATA		1	/* dynamic (data) allocation */
#define	MT_HEADER	2	/* packet header */
#define	MT_SONAME	3	/* socket name */
#define	MT_SOOPTS	4	/* socket options */
#define	MT_FTABLE	5	/* fragment reassembly header */
#define MT_CONTROL	6	/* extra-data protocol message */
#define MT_OOBDATA	7	/* expedited data  */

#ifdef MBUFTYPES
static const char *mbuftypes[] = {
	"mbfree",
	"mbdata",
	"mbheader",
	"mbsoname",
	"mbsopts",
	"mbftable",
	"mbcontrol",
	"mboobdata",
};
#endif

/* flags to m_get/MGET */
#define	M_DONTWAIT	M_NOWAIT
#define	M_WAIT		M_WAITOK

#ifdef MBUFTRACE
/*
 * mbuf allocation tracing
 */
void mowner_init(struct mbuf *, int);
void mowner_ref(struct mbuf *, int);
void m_claim(struct mbuf *, struct mowner *);
void mowner_revoke(struct mbuf *, bool, int);
void mowner_attach(struct mowner *);
void mowner_detach(struct mowner *);
void m_claimm(struct mbuf *, struct mowner *);
#else
#define mowner_init(m, type)		do { } while (/* CONSTCOND */ 0)
#define	mowner_ref(m, flags)		do { } while (/* CONSTCOND */ 0)
#define	mowner_revoke(m, all, flags)	do { } while (/* CONSTCOND */ 0)
#define	m_claim(m, mowner) 		do { } while (/* CONSTCOND */ 0)
#define	mowner_attach(mo)		do { } while (/* CONSTCOND */ 0)
#define	mowner_detach(mo)		do { } while (/* CONSTCOND */ 0)
#define	m_claimm(m, mo)			do { } while (/* CONSTCOND */ 0)
#endif

#define	MCLAIM(m, mo)		m_claim((m), (mo))
#define	MOWNER_ATTACH(mo)	mowner_attach(mo)
#define	MOWNER_DETACH(mo)	mowner_detach(mo)

/*
 * 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.
 *
 * If 'how' is M_WAIT, these macros (and the corresponding functions)
 * are guaranteed to return successfully.
 */
#define	MGET(m, how, type)	m = m_get((how), (type))
#define	MGETHDR(m, how, type)	m = m_gethdr((how), (type))

#if defined(_KERNEL)
#define	_M_
/*
 * Macros for tracking external storage associated with an mbuf.
 */
#ifdef DEBUG
#define MCLREFDEBUGN(m, file, line)					\
do {									\
	(m)->m_ext.ext_nfile = (file);					\
	(m)->m_ext.ext_nline = (line);					\
} while (/* CONSTCOND */ 0)

#define MCLREFDEBUGO(m, file, line)					\
do {									\
	(m)->m_ext.ext_ofile = (file);					\
	(m)->m_ext.ext_oline = (line);					\
} while (/* CONSTCOND */ 0)
#else
#define MCLREFDEBUGN(m, file, line)
#define MCLREFDEBUGO(m, file, line)
#endif

#define	MCLINITREFERENCE(m)						\
do {									\
	KDASSERT(((m)->m_flags & M_EXT) == 0);				\
	(m)->m_ext_ref = (m);						\
	(m)->m_ext.ext_refcnt = 1;					\
	MCLREFDEBUGO((m), __FILE__, __LINE__);				\
	MCLREFDEBUGN((m), NULL, 0);					\
} while (/* CONSTCOND */ 0)

/*
 * Macros for mbuf external storage.
 *
 * MCLGET allocates and adds an mbuf cluster to a normal mbuf;
 * the flag M_EXT is set upon success.
 *
 * MEXTMALLOC allocates external storage and adds it to
 * a normal mbuf; the flag M_EXT is set upon success.
 *
 * MEXTADD adds pre-allocated external storage to
 * a normal mbuf; the flag M_EXT is set upon success.
 */

#define	_MCLGET(m, pool_cache, size, how)				\
do {									\
	(m)->m_ext_storage.ext_buf =					\
	    pool_cache_get_paddr((pool_cache),				\
		(how) == M_WAIT ? (PR_WAITOK|PR_LIMITFAIL) : 0,		\
		&(m)->m_ext_storage.ext_paddr);				\
	if ((m)->m_ext_storage.ext_buf != NULL) {			\
		MCLINITREFERENCE(m);					\
		(m)->m_data = (m)->m_ext.ext_buf;			\
		(m)->m_flags = ((m)->m_flags & ~M_EXTCOPYFLAGS) |	\
				M_EXT|M_CLUSTER|M_EXT_RW;		\
		(m)->m_ext.ext_flags = 0;				\
		(m)->m_ext.ext_size = (size);				\
		(m)->m_ext.ext_free = NULL;				\
		(m)->m_ext.ext_arg = (pool_cache);			\
		/* ext_paddr initialized above */			\
		mowner_ref((m), M_EXT|M_CLUSTER);			\
	}								\
} while (/* CONSTCOND */ 0)

/*
 * The standard mbuf cluster pool.
 */
#define	MCLGET(m, how)	_MCLGET((m), mcl_cache, MCLBYTES, (how))

#define	MEXTMALLOC(m, size, how)					\
do {									\
	(m)->m_ext_storage.ext_buf =					\
	    malloc((size), mbtypes[(m)->m_type], (how));		\
	if ((m)->m_ext_storage.ext_buf != NULL) {			\
		MCLINITREFERENCE(m);					\
		(m)->m_data = (m)->m_ext.ext_buf;			\
		(m)->m_flags = ((m)->m_flags & ~M_EXTCOPYFLAGS) |	\
				M_EXT|M_EXT_RW;				\
		(m)->m_ext.ext_flags = 0;				\
		(m)->m_ext.ext_size = (size);				\
		(m)->m_ext.ext_free = NULL;				\
		(m)->m_ext.ext_arg = NULL;				\
		mowner_ref((m), M_EXT);					\
	}								\
} while (/* CONSTCOND */ 0)

#define	MEXTADD(m, buf, size, type, free, arg)				\
do {									\
	MCLINITREFERENCE(m);						\
	(m)->m_data = (m)->m_ext.ext_buf = (void *)(buf);		\
	(m)->m_flags = ((m)->m_flags & ~M_EXTCOPYFLAGS) | M_EXT;	\
	(m)->m_ext.ext_flags = 0;					\
	(m)->m_ext.ext_size = (size);					\
	(m)->m_ext.ext_free = (free);					\
	(m)->m_ext.ext_arg = (arg);					\
	mowner_ref((m), M_EXT);						\
} while (/* CONSTCOND */ 0)

/*
 * Reset the data pointer on an mbuf.
 */
#define	MRESETDATA(m)							\
do {									\
	if ((m)->m_flags & M_EXT)					\
		(m)->m_data = (m)->m_ext.ext_buf;			\
	else if ((m)->m_flags & M_PKTHDR)				\
		(m)->m_data = (m)->m_pktdat;				\
	else								\
		(m)->m_data = (m)->m_dat;				\
} while (/* CONSTCOND */ 0)

/*
 * MFREE(struct mbuf *m, struct mbuf *n)
 * Free a single mbuf and associated external storage.
 * Place the successor, if any, in n.
 */
#define	MFREE(m, n)							\
	mowner_revoke((m), 1, (m)->m_flags);				\
	mbstat_type_add((m)->m_type, -1);				\
	if ((m)->m_flags & M_PKTHDR)					\
		m_tag_delete_chain((m), NULL);				\
	(n) = (m)->m_next;						\
	if ((m)->m_flags & M_EXT) {					\
		m_ext_free((m));						\
	} else {							\
		KASSERT((m)->m_type != MT_FREE);				\
		(m)->m_type = MT_FREE;					\
		pool_cache_put(mb_cache, (m));				\
	}								\

/*
 * Copy mbuf pkthdr from `from' to `to'.
 * `from' must have M_PKTHDR set, and `to' must be empty.
 */
#define	M_COPY_PKTHDR(to, from)						\
do {									\
	(to)->m_pkthdr = (from)->m_pkthdr;				\
	(to)->m_flags = (from)->m_flags & M_COPYFLAGS;			\
	SLIST_INIT(&(to)->m_pkthdr.tags);				\
	m_tag_copy_chain((to), (from));					\
	(to)->m_data = (to)->m_pktdat;					\
} while (/* CONSTCOND */ 0)

/*
 * Move mbuf pkthdr from `from' to `to'.
 * `from' must have M_PKTHDR set, and `to' must be empty.
 */
#define	M_MOVE_PKTHDR(to, from)	m_move_pkthdr(to, from)

/*
 * Set the m_data pointer of a newly-allocated mbuf (m_get/MGET) to place
 * an object of the specified size at the end of the mbuf, longword aligned.
 */
#define	M_ALIGN(m, len)							\
do {									\
	(m)->m_data += (MLEN - (len)) &~ (sizeof(long) - 1);		\
} while (/* CONSTCOND */ 0)

/*
 * As above, for mbufs allocated with m_gethdr/MGETHDR
 * or initialized by M_COPY_PKTHDR.
 */
#define	MH_ALIGN(m, len)						\
do {									\
	(m)->m_data += (MHLEN - (len)) &~ (sizeof(long) - 1);		\
} while (/* CONSTCOND */ 0)

/*
 * Determine if an mbuf's data area is read-only.  This is true
 * if external storage is read-only mapped, or not marked as R/W,
 * or referenced by more than one mbuf.
 */
#define	M_READONLY(m)							\
	(((m)->m_flags & M_EXT) != 0 &&					\
	  (((m)->m_flags & (M_EXT_ROMAP|M_EXT_RW)) != M_EXT_RW ||	\
	  (m)->m_ext.ext_refcnt > 1))

#define	M_UNWRITABLE(__m, __len)					\
	((__m)->m_len < (__len) || M_READONLY((__m)))
/*
 * Determine if an mbuf's data area is read-only at the MMU.
 */
#define	M_ROMAP(m)							\
	(((m)->m_flags & (M_EXT|M_EXT_ROMAP)) == (M_EXT|M_EXT_ROMAP))

/*
 * Compute the amount of space available
 * before the current start of data in an mbuf.
 */
#define	_M_LEADINGSPACE(m)						\
	((m)->m_flags & M_EXT ? (m)->m_data - (m)->m_ext.ext_buf :	\
	 (m)->m_flags & M_PKTHDR ? (m)->m_data - (m)->m_pktdat :	\
	 (m)->m_data - (m)->m_dat)

#define	M_LEADINGSPACE(m)						\
	(M_READONLY((m)) ? 0 : _M_LEADINGSPACE((m)))

/*
 * Compute the amount of space available
 * after the end of data in an mbuf.
 */
#define	_M_TRAILINGSPACE(m)						\
	((m)->m_flags & M_EXT ? (m)->m_ext.ext_buf + (m)->m_ext.ext_size - \
	 ((m)->m_data + (m)->m_len) :					\
	 &(m)->m_dat[MLEN] - ((m)->m_data + (m)->m_len))

#define	M_TRAILINGSPACE(m)						\
	(M_READONLY((m)) ? 0 : _M_TRAILINGSPACE((m)))

/*
 * Compute the address of an mbuf's data area.
 */
#define	M_BUFADDR(m)							\
	(((m)->m_flags & M_PKTHDR) ? (m)->m_pktdat : (m)->m_dat)

/*
 * Compute the offset of the beginning of the data buffer of a non-ext
 * mbuf.
 */
#define	M_BUFOFFSET(m)							\
	(((m)->m_flags & M_PKTHDR) ?					\
	 offsetof(struct mbuf, m_pktdat) : offsetof(struct mbuf, m_dat))

/*
 * Arrange to prepend space of size plen to mbuf m.
 * If a new mbuf must be allocated, how specifies whether to wait.
 * If how is M_DONTWAIT and allocation fails, the original mbuf chain
 * is freed and m is set to NULL.
 */
#define	M_PREPEND(m, plen, how)						\
do {									\
	if (M_LEADINGSPACE(m) >= (plen)) {				\
		(m)->m_data -= (plen);					\
		(m)->m_len += (plen);					\
	} else								\
		(m) = m_prepend((m), (plen), (how));			\
	if ((m) && (m)->m_flags & M_PKTHDR)				\
		(m)->m_pkthdr.len += (plen);				\
} while (/* CONSTCOND */ 0)

/* change mbuf to new type */
#define MCHTYPE(m, t)							\
do {									\
	KASSERT((t) != MT_FREE);					\
	mbstat_type_add((m)->m_type, -1);				\
	mbstat_type_add(t, 1);						\
	(m)->m_type = t;						\
} while (/* CONSTCOND */ 0)

/* length to m_copy to copy all */
#define	M_COPYALL	-1

/* compatibility with 4.3 */
#define  m_copy(m, o, l)	m_copym((m), (o), (l), M_DONTWAIT)

/*
 * Allow drivers and/or protocols to use the rcvif member of
 * PKTHDR mbufs to store private context information.
 */
#define	M_GETCTX(m, t)		((t)(m)->m_pkthdr.rcvif)
#define	M_SETCTX(m, c)		((void)((m)->m_pkthdr.rcvif = (void *)(c)))

#endif /* defined(_KERNEL) */

/*
 * Simple mbuf queueing system
 *
 * this is basically a SIMPLEQ adapted to mbuf use (ie using
 * m_nextpkt instead of field.sqe_next).
 *
 * m_next is ignored, so queueing chains of mbufs is possible
 */
#define MBUFQ_HEAD(name)					\
struct name {							\
	struct mbuf *mq_first;					\
	struct mbuf **mq_last;					\
}

#define MBUFQ_INIT(q)		do {				\
	(q)->mq_first = NULL;					\
	(q)->mq_last = &(q)->mq_first;				\
} while (/*CONSTCOND*/0)

#define MBUFQ_ENQUEUE(q, m)	do {				\
	(m)->m_nextpkt = NULL;					\
	*(q)->mq_last = (m);					\
	(q)->mq_last = &(m)->m_nextpkt;				\
} while (/*CONSTCOND*/0)

#define MBUFQ_PREPEND(q, m)	do {				\
	if (((m)->m_nextpkt = (q)->mq_first) == NULL)		\
		(q)->mq_last = &(m)->m_nextpkt;			\
	(q)->mq_first = (m);					\
} while (/*CONSTCOND*/0)

#define MBUFQ_DEQUEUE(q, m)	do {				\
	if (((m) = (q)->mq_first) != NULL) { 			\
		if (((q)->mq_first = (m)->m_nextpkt) == NULL)	\
			(q)->mq_last = &(q)->mq_first;		\
		else						\
			(m)->m_nextpkt = NULL;			\
	}							\
} while (/*CONSTCOND*/0)

#define MBUFQ_DRAIN(q)		do {				\
	struct mbuf *__m0;					\
	while ((__m0 = (q)->mq_first) != NULL) {		\
		(q)->mq_first = __m0->m_nextpkt;		\
		m_freem(__m0);					\
	}							\
	(q)->mq_last = &(q)->mq_first;				\
} while (/*CONSTCOND*/0)

#define MBUFQ_FIRST(q)		((q)->mq_first)
#define MBUFQ_NEXT(m)		((m)->m_nextpkt)
#define MBUFQ_LAST(q)		(*(q)->mq_last)

/*
 * Mbuf statistics.
 * For statistics related to mbuf and cluster allocations, see also the
 * pool headers (mb_cache and mcl_cache).
 */
struct mbstat {
	u_long	_m_spare;	/* formerly m_mbufs */
	u_long	_m_spare1;	/* formerly m_clusters */
	u_long	_m_spare2;	/* spare field */
	u_long	_m_spare3;	/* formely 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_short	m_mtypes[256];	/* type specific mbuf allocations */
};

struct mbstat_cpu {
	u_int	m_mtypes[256];	/* type specific mbuf allocations */
};

/*
 * Mbuf sysctl variables.
 */
#define	MBUF_MSIZE		1	/* int: mbuf base size */
#define	MBUF_MCLBYTES		2	/* int: mbuf cluster size */
#define	MBUF_NMBCLUSTERS	3	/* int: limit on the # of clusters */
#define	MBUF_MBLOWAT		4	/* int: mbuf low water mark */
#define	MBUF_MCLLOWAT		5	/* int: mbuf cluster low water mark */
#define	MBUF_STATS		6	/* struct: mbstat */
#define	MBUF_MOWNERS		7	/* struct: m_owner[] */
#define	MBUF_MAXID		8	/* number of valid MBUF ids */

#define	CTL_MBUF_NAMES {						\
	{ 0, 0 },							\
	{ "msize", CTLTYPE_INT },					\
	{ "mclbytes", CTLTYPE_INT },					\
	{ "nmbclusters", CTLTYPE_INT },					\
	{ "mblowat", CTLTYPE_INT },					\
	{ "mcllowat", CTLTYPE_INT },					\
	{ 0 /* "stats" */, CTLTYPE_STRUCT },				\
	{ 0 /* "mowners" */, CTLTYPE_STRUCT },				\
}

#ifdef	_KERNEL
extern struct mbstat mbstat;
extern int	nmbclusters;		/* limit on the # of clusters */
extern int	mblowat;		/* mbuf low water mark */
extern int	mcllowat;		/* mbuf cluster low water mark */
extern int	max_linkhdr;		/* largest link-level header */
extern int	max_protohdr;		/* largest protocol header */
extern int	max_hdr;		/* largest link+protocol header */
extern int	max_datalen;		/* MHLEN - max_hdr */
extern const int msize;			/* mbuf base size */
extern const int mclbytes;		/* mbuf cluster size */
extern pool_cache_t mb_cache;
extern pool_cache_t mcl_cache;
#ifdef MBUFTRACE
LIST_HEAD(mownerhead, mowner);
extern struct mownerhead mowners;
extern struct mowner unknown_mowners[];
extern struct mowner revoked_mowner;
#endif

MALLOC_DECLARE(M_MBUF);
MALLOC_DECLARE(M_SONAME);

struct	mbuf *m_copym(struct mbuf *, int, int, int);
struct	mbuf *m_copypacket(struct mbuf *, int);
struct	mbuf *m_devget(char *, int, int, struct ifnet *,
			    void (*copy)(const void *, void *, size_t));
struct	mbuf *m_dup(struct mbuf *, int, int, int);
struct	mbuf *m_free(struct mbuf *);
struct	mbuf *m_get(int, int);
struct	mbuf *m_getclr(int, int);
struct	mbuf *m_gethdr(int, int);
struct	mbuf *m_prepend(struct mbuf *,int, int);
struct	mbuf *m_pulldown(struct mbuf *, int, int, int *);
struct	mbuf *m_pullup(struct mbuf *, int);
struct	mbuf *m_copyup(struct mbuf *, int, int);
struct	mbuf *m_split(struct mbuf *,int, int);
struct	mbuf *m_getptr(struct mbuf *, int, int *);
void	m_adj(struct mbuf *, int);
struct	mbuf *m_defrag(struct mbuf *, int);
int	m_apply(struct mbuf *, int, int,
		int (*)(void *, void *, unsigned int), void *);
void	m_cat(struct mbuf *,struct mbuf *);
void	m_clget(struct mbuf *, int);
int	m_mballoc(int, int);
void	m_copyback(struct mbuf *, int, int, const void *);
struct	mbuf *m_copyback_cow(struct mbuf *, int, int, const void *, int);
int 	m_makewritable(struct mbuf **, int, int, int);
struct	mbuf *m_getcl(int, int, int);
void	m_copydata(struct mbuf *, int, int, void *);
void	m_freem(struct mbuf *);
void	m_reclaim(void *, int);
void	mbinit(void);
void	m_ext_free(struct mbuf *);
char *	m_mapin(struct mbuf *);
void	m_move_pkthdr(struct mbuf *, struct mbuf *);

bool	m_ensure_contig(struct mbuf **, int);
struct mbuf *m_add(struct mbuf *, struct mbuf *);
void	m_align(struct mbuf *, int);
int	m_append(struct mbuf *, int, const void *);

/* Inline routines. */
static __inline u_int m_length(const struct mbuf *) __unused;

/* Statistics */
void mbstat_type_add(int, int);

/* Packet tag routines */
struct	m_tag *m_tag_get(int, int, int);
void	m_tag_free(struct m_tag *);
void	m_tag_prepend(struct mbuf *, struct m_tag *);
void	m_tag_unlink(struct mbuf *, struct m_tag *);
void	m_tag_delete(struct mbuf *, struct m_tag *);
void	m_tag_delete_chain(struct mbuf *, struct m_tag *);
void	m_tag_delete_nonpersistent(struct mbuf *);
struct	m_tag *m_tag_find(const struct mbuf *, int, struct m_tag *);
struct	m_tag *m_tag_copy(struct m_tag *);
int	m_tag_copy_chain(struct mbuf *, struct mbuf *);
void	m_tag_init(struct mbuf *);
struct	m_tag *m_tag_first(struct mbuf *);
struct	m_tag *m_tag_next(struct mbuf *, struct m_tag *);

/* Packet tag types */
#define PACKET_TAG_NONE				0  /* Nothing */
#define PACKET_TAG_VLAN				1  /* VLAN ID */
#define PACKET_TAG_ENCAP			2  /* encapsulation data */
#define PACKET_TAG_ESP				3  /* ESP information */
#define PACKET_TAG_PF				11 /* packet filter */
#define PACKET_TAG_ALTQ_QID			12 /* ALTQ queue id */

#define PACKET_TAG_IPSEC_IN_CRYPTO_DONE		16
#define PACKET_TAG_IPSEC_IN_DONE		17
#define PACKET_TAG_IPSEC_OUT_DONE		18
#define	PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED	19  /* NIC IPsec crypto req'ed */
#define	PACKET_TAG_IPSEC_IN_COULD_DO_CRYPTO	20  /* NIC notifies IPsec */
#define	PACKET_TAG_IPSEC_PENDING_TDB		21  /* Reminder to do IPsec */

#define	PACKET_TAG_IPSEC_SOCKET			22 /* IPSEC socket ref */
#define	PACKET_TAG_IPSEC_HISTORY		23 /* IPSEC history */

#define	PACKET_TAG_IPSEC_NAT_T_PORTS		25 /* two uint16_t */

#define	PACKET_TAG_INET6			26 /* IPv6 info */

#define	PACKET_TAG_ECO_RETRYPARMS		27 /* Econet retry parameters */

#define	PACKET_TAG_TUNNEL_INFO			28 /* tunnel identification and
						    * protocol callback, for
						    * loop detection/recovery
						    */

/*
 * Return the number of bytes in the mbuf chain, m.
 */
static __inline u_int
m_length(const struct mbuf *m)
{
	const struct mbuf *m0;
	u_int pktlen;

	if ((m->m_flags & M_PKTHDR) != 0)
		return m->m_pkthdr.len;

	pktlen = 0;
	for (m0 = m; m0 != NULL; m0 = m0->m_next)
		pktlen += m0->m_len;
	return pktlen;
}

void m_print(const struct mbuf *, const char *, void (*)(const char *, ...)
    __printflike(1, 2));

#endif /* _KERNEL */
#endif /* !_SYS_MBUF_H_ */
