xref: /freebsd-11-stable/sys/sys/mbuf.h

/*-
 * 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
 * $FreeBSD: stable/11/sys/sys/mbuf.h 331722 2018-03-29 02:50:57Z eadler $
 */

#ifndef _SYS_MBUF_H_
#define	_SYS_MBUF_H_

/* XXX: These includes suck. Sorry! */
#include <sys/queue.h>
#ifdef _KERNEL
#include <sys/systm.h>
#include <vm/uma.h>
#ifdef WITNESS
#include <sys/lock.h>
#endif
#endif

#ifdef _KERNEL
#include <sys/sdt.h>

#define	MBUF_PROBE1(probe, arg0)					\
	SDT_PROBE1(sdt, , , probe, arg0)
#define	MBUF_PROBE2(probe, arg0, arg1)					\
	SDT_PROBE2(sdt, , , probe, arg0, arg1)
#define	MBUF_PROBE3(probe, arg0, arg1, arg2)				\
	SDT_PROBE3(sdt, , , probe, arg0, arg1, arg2)
#define	MBUF_PROBE4(probe, arg0, arg1, arg2, arg3)			\
	SDT_PROBE4(sdt, , , probe, arg0, arg1, arg2, arg3)
#define	MBUF_PROBE5(probe, arg0, arg1, arg2, arg3, arg4)		\
	SDT_PROBE5(sdt, , , probe, arg0, arg1, arg2, arg3, arg4)

SDT_PROBE_DECLARE(sdt, , , m__init);
SDT_PROBE_DECLARE(sdt, , , m__gethdr);
SDT_PROBE_DECLARE(sdt, , , m__get);
SDT_PROBE_DECLARE(sdt, , , m__getcl);
SDT_PROBE_DECLARE(sdt, , , m__clget);
SDT_PROBE_DECLARE(sdt, , , m__cljget);
SDT_PROBE_DECLARE(sdt, , , m__cljset);
SDT_PROBE_DECLARE(sdt, , , m__free);
SDT_PROBE_DECLARE(sdt, , , m__freem);

#endif /* _KERNEL */

/*
 * Mbufs are of a single size, MSIZE (sys/param.h), which includes overhead.
 * An mbuf may add a single "mbuf cluster" of size MCLBYTES (also in
 * sys/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.  Additionally, it is possible to allocate a separate buffer
 * externally and attach it to the mbuf in a way similar to that of mbuf
 * clusters.
 *
 * NB: These calculation do not take actual compiler-induced alignment and
 * padding inside the complete struct mbuf into account.  Appropriate
 * attention is required when changing members of struct mbuf.
 *
 * MLEN is data length in a normal mbuf.
 * MHLEN is data length in an mbuf with pktheader.
 * MINCLSIZE is a smallest amount of data that should be put into cluster.
 *
 * Compile-time assertions in uipc_mbuf.c test these values to ensure that
 * they are sensible.
 */
struct mbuf;
#define	MHSIZE		offsetof(struct mbuf, m_dat)
#define	MPKTHSIZE	offsetof(struct mbuf, m_pktdat)
#define	MLEN		((int)(MSIZE - MHSIZE))
#define	MHLEN		((int)(MSIZE - MPKTHSIZE))
#define	MINCLSIZE	(MHLEN + 1)

#ifdef _KERNEL
/*-
 * Macro for type conversion: convert mbuf pointer to data pointer of correct
 * type:
 *
 * mtod(m, t)	-- Convert mbuf pointer to data pointer of correct type.
 * mtodo(m, o) -- Same as above but with offset 'o' into data.
 */
#define	mtod(m, t)	((t)((m)->m_data))
#define	mtodo(m, o)	((void *)(((m)->m_data) + (o)))

/*
 * Argument structure passed to UMA routines during mbuf and packet
 * allocations.
 */
struct mb_args {
	int	flags;	/* Flags for mbuf being allocated */
	short	type;	/* Type of mbuf being allocated */
};
#endif /* _KERNEL */

/*
 * Packet tag structure (see below for details).
 */
struct m_tag {
	SLIST_ENTRY(m_tag)	m_tag_link;	/* List of packet tags */
	u_int16_t		m_tag_id;	/* Tag ID */
	u_int16_t		m_tag_len;	/* Length of data */
	u_int32_t		m_tag_cookie;	/* ABI/Module ID */
	void			(*m_tag_free)(struct m_tag *);
};

/*
 * Record/packet header in first mbuf of chain; valid only if M_PKTHDR is set.
 * Size ILP32: 48
 *	 LP64: 56
 * Compile-time assertions in uipc_mbuf.c test these values to ensure that
 * they are correct.
 */
struct pkthdr {
	struct ifnet	*rcvif;		/* rcv interface */
	SLIST_HEAD(packet_tags, m_tag) tags; /* list of packet tags */
	int32_t		 len;		/* total packet length */

	/* Layer crossing persistent information. */
	uint32_t	 flowid;	/* packet's 4-tuple system */
	uint64_t	 csum_flags;	/* checksum and offload features */
	uint16_t	 fibnum;	/* this packet should use this fib */
	uint8_t		 cosqos;	/* class/quality of service */
	uint8_t		 rsstype;	/* hash type */
	uint8_t		 l2hlen;	/* layer 2 header length */
	uint8_t		 l3hlen;	/* layer 3 header length */
	uint8_t		 l4hlen;	/* layer 4 header length */
	uint8_t		 l5hlen;	/* layer 5 header length */
	union {
		uint8_t  eight[8];
		uint16_t sixteen[4];
		uint32_t thirtytwo[2];
		uint64_t sixtyfour[1];
		uintptr_t unintptr[1];
		void	*ptr;
	} PH_per;

	/* Layer specific non-persistent local storage for reassembly, etc. */
	union {
		uint8_t  eight[8];
		uint16_t sixteen[4];
		uint32_t thirtytwo[2];
		uint64_t sixtyfour[1];
		uintptr_t unintptr[1];
		void 	*ptr;
	} PH_loc;
};
#define	ether_vtag	PH_per.sixteen[0]
#define	PH_vt		PH_per
#define	vt_nrecs	sixteen[0]
#define	tso_segsz	PH_per.sixteen[1]
#define	csum_phsum	PH_per.sixteen[2]
#define	csum_data	PH_per.thirtytwo[1]

/*
 * Description of external storage mapped into mbuf; valid only if M_EXT is
 * set.
 * Size ILP32: 28
 *	 LP64: 48
 * Compile-time assertions in uipc_mbuf.c test these values to ensure that
 * they are correct.
 */
struct m_ext {
	union {
		volatile u_int	 ext_count;	/* value of ref count info */
		volatile u_int	*ext_cnt;	/* pointer to ref count info */
	};
	caddr_t		 ext_buf;	/* start of buffer */
	uint32_t	 ext_size;	/* size of buffer, for ext_free */
	uint32_t	 ext_type:8,	/* type of external storage */
			 ext_flags:24;	/* external storage mbuf flags */
	void		(*ext_free)	/* free routine if not the usual */
			    (struct mbuf *, void *, void *);
	void		*ext_arg1;	/* optional argument pointer */
	void		*ext_arg2;	/* optional argument pointer */
};

/*
 * The core of the mbuf object along with some shortcut defines for practical
 * purposes.
 */
struct mbuf {
	/*
	 * Header present at the beginning of every mbuf.
	 * Size ILP32: 24
	 *      LP64: 32
	 * Compile-time assertions in uipc_mbuf.c test these values to ensure
	 * that they are correct.
	 */
	union {	/* next buffer in chain */
		struct mbuf		*m_next;
		SLIST_ENTRY(mbuf)	m_slist;
		STAILQ_ENTRY(mbuf)	m_stailq;
	};
	union {	/* next chain in queue/record */
		struct mbuf		*m_nextpkt;
		SLIST_ENTRY(mbuf)	m_slistpkt;
		STAILQ_ENTRY(mbuf)	m_stailqpkt;
	};
	caddr_t		 m_data;	/* location of data */
	int32_t		 m_len;		/* amount of data in this mbuf */
	uint32_t	 m_type:8,	/* type of data in this mbuf */
			 m_flags:24;	/* flags; see below */
#if !defined(__LP64__)
	uint32_t	 m_pad;		/* pad for 64bit alignment */
#endif

	/*
	 * A set of optional headers (packet header, external storage header)
	 * and internal data storage.  Historically, these arrays were sized
	 * to MHLEN (space left after a packet header) and MLEN (space left
	 * after only a regular mbuf header); they are now variable size in
	 * order to support future work on variable-size mbufs.
	 */
	union {
		struct {
			struct pkthdr	m_pkthdr;	/* M_PKTHDR set */
			union {
				struct m_ext	m_ext;	/* M_EXT set */
				char		m_pktdat[0];
			};
		};
		char	m_dat[0];			/* !M_PKTHDR, !M_EXT */
	};
};

/*
 * mbuf flags of global significance and layer crossing.
 * Those of only protocol/layer specific significance are to be mapped
 * to M_PROTO[1-12] and cleared at layer handoff boundaries.
 * NB: Limited to the lower 24 bits.
 */
#define	M_EXT		0x00000001 /* has associated external storage */
#define	M_PKTHDR	0x00000002 /* start of record */
#define	M_EOR		0x00000004 /* end of record */
#define	M_RDONLY	0x00000008 /* associated data is marked read-only */
#define	M_BCAST		0x00000010 /* send/received as link-level broadcast */
#define	M_MCAST		0x00000020 /* send/received as link-level multicast */
#define	M_PROMISC	0x00000040 /* packet was not for us */
#define	M_VLANTAG	0x00000080 /* ether_vtag is valid */
#define	M_UNUSED_8	0x00000100 /* --available-- */
#define	M_NOFREE	0x00000200 /* do not free mbuf, embedded in cluster */

#define	M_PROTO1	0x00001000 /* protocol-specific */
#define	M_PROTO2	0x00002000 /* protocol-specific */
#define	M_PROTO3	0x00004000 /* protocol-specific */
#define	M_PROTO4	0x00008000 /* protocol-specific */
#define	M_PROTO5	0x00010000 /* protocol-specific */
#define	M_PROTO6	0x00020000 /* protocol-specific */
#define	M_PROTO7	0x00040000 /* protocol-specific */
#define	M_PROTO8	0x00080000 /* protocol-specific */
#define	M_PROTO9	0x00100000 /* protocol-specific */
#define	M_PROTO10	0x00200000 /* protocol-specific */
#define	M_PROTO11	0x00400000 /* protocol-specific */
#define	M_PROTO12	0x00800000 /* protocol-specific */

#define MB_DTOR_SKIP	0x1	/* don't pollute the cache by touching a freed mbuf */

/*
 * Flags to purge when crossing layers.
 */
#define	M_PROTOFLAGS \
    (M_PROTO1|M_PROTO2|M_PROTO3|M_PROTO4|M_PROTO5|M_PROTO6|M_PROTO7|M_PROTO8|\
     M_PROTO9|M_PROTO10|M_PROTO11|M_PROTO12)

/*
 * Flags preserved when copying m_pkthdr.
 */
#define M_COPYFLAGS \
    (M_PKTHDR|M_EOR|M_RDONLY|M_BCAST|M_MCAST|M_PROMISC|M_VLANTAG| \
     M_PROTOFLAGS)

/*
 * Mbuf flag description for use with printf(9) %b identifier.
 */
#define	M_FLAG_BITS \
    "\20\1M_EXT\2M_PKTHDR\3M_EOR\4M_RDONLY\5M_BCAST\6M_MCAST" \
    "\7M_PROMISC\10M_VLANTAG"
#define	M_FLAG_PROTOBITS \
    "\15M_PROTO1\16M_PROTO2\17M_PROTO3\20M_PROTO4\21M_PROTO5" \
    "\22M_PROTO6\23M_PROTO7\24M_PROTO8\25M_PROTO9\26M_PROTO10" \
    "\27M_PROTO11\30M_PROTO12"
#define	M_FLAG_PRINTF (M_FLAG_BITS M_FLAG_PROTOBITS)

/*
 * Network interface cards are able to hash protocol fields (such as IPv4
 * addresses and TCP port numbers) classify packets into flows.  These flows
 * can then be used to maintain ordering while delivering packets to the OS
 * via parallel input queues, as well as to provide a stateless affinity
 * model.  NIC drivers can pass up the hash via m->m_pkthdr.flowid, and set
 * m_flag fields to indicate how the hash should be interpreted by the
 * network stack.
 *
 * Most NICs support RSS, which provides ordering and explicit affinity, and
 * use the hash m_flag bits to indicate what header fields were covered by
 * the hash.  M_HASHTYPE_OPAQUE and M_HASHTYPE_OPAQUE_HASH can be set by non-
 * RSS cards or configurations that provide an opaque flow identifier, allowing
 * for ordering and distribution without explicit affinity.  Additionally,
 * M_HASHTYPE_OPAQUE_HASH indicates that the flow identifier has hash
 * properties.
 */
#define	M_HASHTYPE_HASHPROP		0x80	/* has hash properties */
#define	M_HASHTYPE_HASH(t)		(M_HASHTYPE_HASHPROP | (t))
/* Microsoft RSS standard hash types */
#define	M_HASHTYPE_NONE			0
#define	M_HASHTYPE_RSS_IPV4		M_HASHTYPE_HASH(1) /* IPv4 2-tuple */
#define	M_HASHTYPE_RSS_TCP_IPV4		M_HASHTYPE_HASH(2) /* TCPv4 4-tuple */
#define	M_HASHTYPE_RSS_IPV6		M_HASHTYPE_HASH(3) /* IPv6 2-tuple */
#define	M_HASHTYPE_RSS_TCP_IPV6		M_HASHTYPE_HASH(4) /* TCPv6 4-tuple */
#define	M_HASHTYPE_RSS_IPV6_EX		M_HASHTYPE_HASH(5) /* IPv6 2-tuple +
							    * ext hdrs */
#define	M_HASHTYPE_RSS_TCP_IPV6_EX	M_HASHTYPE_HASH(6) /* TCPv6 4-tuple +
							    * ext hdrs */
/* Non-standard RSS hash types */
#define	M_HASHTYPE_RSS_UDP_IPV4		M_HASHTYPE_HASH(7) /* IPv4 UDP 4-tuple*/
#define	M_HASHTYPE_RSS_UDP_IPV4_EX	M_HASHTYPE_HASH(8) /* IPv4 UDP 4-tuple +
							    * ext hdrs */
#define	M_HASHTYPE_RSS_UDP_IPV6		M_HASHTYPE_HASH(9) /* IPv6 UDP 4-tuple*/
#define	M_HASHTYPE_RSS_UDP_IPV6_EX	M_HASHTYPE_HASH(10)/* IPv6 UDP 4-tuple +
							    * ext hdrs */

#define	M_HASHTYPE_OPAQUE		63	/* ordering, not affinity */
#define	M_HASHTYPE_OPAQUE_HASH		M_HASHTYPE_HASH(M_HASHTYPE_OPAQUE)
						/* ordering+hash, not affinity*/

#define	M_HASHTYPE_CLEAR(m)	((m)->m_pkthdr.rsstype = 0)
#define	M_HASHTYPE_GET(m)	((m)->m_pkthdr.rsstype)
#define	M_HASHTYPE_SET(m, v)	((m)->m_pkthdr.rsstype = (v))
#define	M_HASHTYPE_TEST(m, v)	(M_HASHTYPE_GET(m) == (v))
#define	M_HASHTYPE_ISHASH(m)	(M_HASHTYPE_GET(m) & M_HASHTYPE_HASHPROP)

/*
 * COS/QOS class and quality of service tags.
 * It uses DSCP code points as base.
 */
#define	QOS_DSCP_CS0		0x00
#define	QOS_DSCP_DEF		QOS_DSCP_CS0
#define	QOS_DSCP_CS1		0x20
#define	QOS_DSCP_AF11		0x28
#define	QOS_DSCP_AF12		0x30
#define	QOS_DSCP_AF13		0x38
#define	QOS_DSCP_CS2		0x40
#define	QOS_DSCP_AF21		0x48
#define	QOS_DSCP_AF22		0x50
#define	QOS_DSCP_AF23		0x58
#define	QOS_DSCP_CS3		0x60
#define	QOS_DSCP_AF31		0x68
#define	QOS_DSCP_AF32		0x70
#define	QOS_DSCP_AF33		0x78
#define	QOS_DSCP_CS4		0x80
#define	QOS_DSCP_AF41		0x88
#define	QOS_DSCP_AF42		0x90
#define	QOS_DSCP_AF43		0x98
#define	QOS_DSCP_CS5		0xa0
#define	QOS_DSCP_EF		0xb8
#define	QOS_DSCP_CS6		0xc0
#define	QOS_DSCP_CS7		0xe0

/*
 * External mbuf storage buffer types.
 */
#define	EXT_CLUSTER	1	/* mbuf cluster */
#define	EXT_SFBUF	2	/* sendfile(2)'s sf_buf */
#define	EXT_JUMBOP	3	/* jumbo cluster page sized */
#define	EXT_JUMBO9	4	/* jumbo cluster 9216 bytes */
#define	EXT_JUMBO16	5	/* jumbo cluster 16184 bytes */
#define	EXT_PACKET	6	/* mbuf+cluster from packet zone */
#define	EXT_MBUF	7	/* external mbuf reference (M_IOVEC) */
#define	EXT_SFBUF_NOCACHE 8	/* sendfile(2)'s sf_buf not to be cached */

#define	EXT_VENDOR1	224	/* for vendor-internal use */
#define	EXT_VENDOR2	225	/* for vendor-internal use */
#define	EXT_VENDOR3	226	/* for vendor-internal use */
#define	EXT_VENDOR4	227	/* for vendor-internal use */

#define	EXT_EXP1	244	/* for experimental use */
#define	EXT_EXP2	245	/* for experimental use */
#define	EXT_EXP3	246	/* for experimental use */
#define	EXT_EXP4	247	/* for experimental use */

#define	EXT_NET_DRV	252	/* custom ext_buf provided by net driver(s) */
#define	EXT_MOD_TYPE	253	/* custom module's ext_buf type */
#define	EXT_DISPOSABLE	254	/* can throw this buffer away w/page flipping */
#define	EXT_EXTREF	255	/* has externally maintained ext_cnt ptr */

/*
 * Flags for external mbuf buffer types.
 * NB: limited to the lower 24 bits.
 */
#define	EXT_FLAG_EMBREF		0x000001	/* embedded ext_count */
#define	EXT_FLAG_EXTREF		0x000002	/* external ext_cnt, notyet */

#define	EXT_FLAG_NOFREE		0x000010	/* don't free mbuf to pool, notyet */

#define	EXT_FLAG_VENDOR1	0x010000	/* for vendor-internal use */
#define	EXT_FLAG_VENDOR2	0x020000	/* for vendor-internal use */
#define	EXT_FLAG_VENDOR3	0x040000	/* for vendor-internal use */
#define	EXT_FLAG_VENDOR4	0x080000	/* for vendor-internal use */

#define	EXT_FLAG_EXP1		0x100000	/* for experimental use */
#define	EXT_FLAG_EXP2		0x200000	/* for experimental use */
#define	EXT_FLAG_EXP3		0x400000	/* for experimental use */
#define	EXT_FLAG_EXP4		0x800000	/* for experimental use */

/*
 * EXT flag description for use with printf(9) %b identifier.
 */
#define	EXT_FLAG_BITS \
    "\20\1EXT_FLAG_EMBREF\2EXT_FLAG_EXTREF\5EXT_FLAG_NOFREE" \
    "\21EXT_FLAG_VENDOR1\22EXT_FLAG_VENDOR2\23EXT_FLAG_VENDOR3" \
    "\24EXT_FLAG_VENDOR4\25EXT_FLAG_EXP1\26EXT_FLAG_EXP2\27EXT_FLAG_EXP3" \
    "\30EXT_FLAG_EXP4"

/*
 * External reference/free functions.
 */
void sf_ext_free(void *, void *);
void sf_ext_free_nocache(void *, void *);

/*
 * Flags indicating checksum, segmentation and other offload work to be
 * done, or already done, by hardware or lower layers.  It is split into
 * separate inbound and outbound flags.
 *
 * Outbound flags that are set by upper protocol layers requesting lower
 * layers, or ideally the hardware, to perform these offloading tasks.
 * For outbound packets this field and its flags can be directly tested
 * against ifnet if_hwassist.
 */
#define	CSUM_IP			0x00000001	/* IP header checksum offload */
#define	CSUM_IP_UDP		0x00000002	/* UDP checksum offload */
#define	CSUM_IP_TCP		0x00000004	/* TCP checksum offload */
#define	CSUM_IP_SCTP		0x00000008	/* SCTP checksum offload */
#define	CSUM_IP_TSO		0x00000010	/* TCP segmentation offload */
#define	CSUM_IP_ISCSI		0x00000020	/* iSCSI checksum offload */

#define	CSUM_IP6_UDP		0x00000200	/* UDP checksum offload */
#define	CSUM_IP6_TCP		0x00000400	/* TCP checksum offload */
#define	CSUM_IP6_SCTP		0x00000800	/* SCTP checksum offload */
#define	CSUM_IP6_TSO		0x00001000	/* TCP segmentation offload */
#define	CSUM_IP6_ISCSI		0x00002000	/* iSCSI checksum offload */

/* Inbound checksum support where the checksum was verified by hardware. */
#define	CSUM_L3_CALC		0x01000000	/* calculated layer 3 csum */
#define	CSUM_L3_VALID		0x02000000	/* checksum is correct */
#define	CSUM_L4_CALC		0x04000000	/* calculated layer 4 csum */
#define	CSUM_L4_VALID		0x08000000	/* checksum is correct */
#define	CSUM_L5_CALC		0x10000000	/* calculated layer 5 csum */
#define	CSUM_L5_VALID		0x20000000	/* checksum is correct */
#define	CSUM_COALESCED		0x40000000	/* contains merged segments */

/*
 * CSUM flag description for use with printf(9) %b identifier.
 */
#define	CSUM_BITS \
    "\20\1CSUM_IP\2CSUM_IP_UDP\3CSUM_IP_TCP\4CSUM_IP_SCTP\5CSUM_IP_TSO" \
    "\6CSUM_IP_ISCSI" \
    "\12CSUM_IP6_UDP\13CSUM_IP6_TCP\14CSUM_IP6_SCTP\15CSUM_IP6_TSO" \
    "\16CSUM_IP6_ISCSI" \
    "\31CSUM_L3_CALC\32CSUM_L3_VALID\33CSUM_L4_CALC\34CSUM_L4_VALID" \
    "\35CSUM_L5_CALC\36CSUM_L5_VALID\37CSUM_COALESCED"

/* CSUM flags compatibility mappings. */
#define	CSUM_IP_CHECKED		CSUM_L3_CALC
#define	CSUM_IP_VALID		CSUM_L3_VALID
#define	CSUM_DATA_VALID		CSUM_L4_VALID
#define	CSUM_PSEUDO_HDR		CSUM_L4_CALC
#define	CSUM_SCTP_VALID		CSUM_L4_VALID
#define	CSUM_DELAY_DATA		(CSUM_TCP|CSUM_UDP)
#define	CSUM_DELAY_IP		CSUM_IP		/* Only v4, no v6 IP hdr csum */
#define	CSUM_DELAY_DATA_IPV6	(CSUM_TCP_IPV6|CSUM_UDP_IPV6)
#define	CSUM_DATA_VALID_IPV6	CSUM_DATA_VALID
#define	CSUM_TCP		CSUM_IP_TCP
#define	CSUM_UDP		CSUM_IP_UDP
#define	CSUM_SCTP		CSUM_IP_SCTP
#define	CSUM_TSO		(CSUM_IP_TSO|CSUM_IP6_TSO)
#define	CSUM_UDP_IPV6		CSUM_IP6_UDP
#define	CSUM_TCP_IPV6		CSUM_IP6_TCP
#define	CSUM_SCTP_IPV6		CSUM_IP6_SCTP

/*
 * mbuf types describing the content of the mbuf (including external storage).
 */
#define	MT_NOTMBUF	0	/* USED INTERNALLY ONLY! Object is not mbuf */
#define	MT_DATA		1	/* dynamic (data) allocation */
#define	MT_HEADER	MT_DATA	/* packet header, use M_PKTHDR instead */

#define	MT_VENDOR1	4	/* for vendor-internal use */
#define	MT_VENDOR2	5	/* for vendor-internal use */
#define	MT_VENDOR3	6	/* for vendor-internal use */
#define	MT_VENDOR4	7	/* for vendor-internal use */

#define	MT_SONAME	8	/* socket name */

#define	MT_EXP1		9	/* for experimental use */
#define	MT_EXP2		10	/* for experimental use */
#define	MT_EXP3		11	/* for experimental use */
#define	MT_EXP4		12	/* for experimental use */

#define	MT_CONTROL	14	/* extra-data protocol message */
#define	MT_OOBDATA	15	/* expedited data  */
#define	MT_NTYPES	16	/* number of mbuf types for mbtypes[] */

#define	MT_NOINIT	255	/* Not a type but a flag to allocate
				   a non-initialized mbuf */

/*
 * String names of mbuf-related UMA(9) and malloc(9) types.  Exposed to
 * !_KERNEL so that monitoring tools can look up the zones with
 * libmemstat(3).
 */
#define	MBUF_MEM_NAME		"mbuf"
#define	MBUF_CLUSTER_MEM_NAME	"mbuf_cluster"
#define	MBUF_PACKET_MEM_NAME	"mbuf_packet"
#define	MBUF_JUMBOP_MEM_NAME	"mbuf_jumbo_page"
#define	MBUF_JUMBO9_MEM_NAME	"mbuf_jumbo_9k"
#define	MBUF_JUMBO16_MEM_NAME	"mbuf_jumbo_16k"
#define	MBUF_TAG_MEM_NAME	"mbuf_tag"
#define	MBUF_EXTREFCNT_MEM_NAME	"mbuf_ext_refcnt"

#ifdef _KERNEL

#ifdef WITNESS
#define	MBUF_CHECKSLEEP(how) do {					\
	if (how == M_WAITOK)						\
		WITNESS_WARN(WARN_GIANTOK | WARN_SLEEPOK, NULL,		\
		    "Sleeping in \"%s\"", __func__);			\
} while (0)
#else
#define	MBUF_CHECKSLEEP(how)
#endif

/*
 * Network buffer allocation API
 *
 * The rest of it is defined in kern/kern_mbuf.c
 */
extern uma_zone_t	zone_mbuf;
extern uma_zone_t	zone_clust;
extern uma_zone_t	zone_pack;
extern uma_zone_t	zone_jumbop;
extern uma_zone_t	zone_jumbo9;
extern uma_zone_t	zone_jumbo16;

void		 mb_dupcl(struct mbuf *, struct mbuf *);
void		 mb_free_ext(struct mbuf *);
void		 m_adj(struct mbuf *, int);
int		 m_apply(struct mbuf *, int, int,
		    int (*)(void *, void *, u_int), void *);
int		 m_append(struct mbuf *, int, c_caddr_t);
void		 m_cat(struct mbuf *, struct mbuf *);
void		 m_catpkt(struct mbuf *, struct mbuf *);
int		 m_clget(struct mbuf *m, int how);
void 		*m_cljget(struct mbuf *m, int how, int size);
struct mbuf	*m_collapse(struct mbuf *, int, int);
void		 m_copyback(struct mbuf *, int, int, c_caddr_t);
void		 m_copydata(const struct mbuf *, int, int, caddr_t);
struct mbuf	*m_copym(struct mbuf *, int, int, int);
struct mbuf	*m_copypacket(struct mbuf *, int);
void		 m_copy_pkthdr(struct mbuf *, struct mbuf *);
struct mbuf	*m_copyup(struct mbuf *, int, int);
struct mbuf	*m_defrag(struct mbuf *, int);
void		 m_demote_pkthdr(struct mbuf *);
void		 m_demote(struct mbuf *, int, int);
struct mbuf	*m_devget(char *, int, int, struct ifnet *,
		    void (*)(char *, caddr_t, u_int));
struct mbuf	*m_dup(const struct mbuf *, int);
int		 m_dup_pkthdr(struct mbuf *, const struct mbuf *, int);
void		 m_extadd(struct mbuf *, caddr_t, u_int,
		    void (*)(struct mbuf *, void *, void *), void *, void *,
		    int, int);
u_int		 m_fixhdr(struct mbuf *);
struct mbuf	*m_fragment(struct mbuf *, int, int);
void		 m_freem(struct mbuf *);
struct mbuf	*m_get2(int, int, short, int);
struct mbuf	*m_getjcl(int, short, int, int);
struct mbuf	*m_getm2(struct mbuf *, int, int, short, int);
struct mbuf	*m_getptr(struct mbuf *, int, int *);
u_int		 m_length(struct mbuf *, struct mbuf **);
int		 m_mbuftouio(struct uio *, struct mbuf *, int);
void		 m_move_pkthdr(struct mbuf *, struct mbuf *);
int		 m_pkthdr_init(struct mbuf *, int);
struct mbuf	*m_prepend(struct mbuf *, int, int);
void		 m_print(const struct mbuf *, int);
struct mbuf	*m_pulldown(struct mbuf *, int, int, int *);
struct mbuf	*m_pullup(struct mbuf *, int);
int		 m_sanity(struct mbuf *, int);
struct mbuf	*m_split(struct mbuf *, int, int);
struct mbuf	*m_uiotombuf(struct uio *, int, int, int, int);
struct mbuf	*m_unshare(struct mbuf *, int);

static __inline int
m_gettype(int size)
{
	int type;

	switch (size) {
	case MSIZE:
		type = EXT_MBUF;
		break;
	case MCLBYTES:
		type = EXT_CLUSTER;
		break;
#if MJUMPAGESIZE != MCLBYTES
	case MJUMPAGESIZE:
		type = EXT_JUMBOP;
		break;
#endif
	case MJUM9BYTES:
		type = EXT_JUMBO9;
		break;
	case MJUM16BYTES:
		type = EXT_JUMBO16;
		break;
	default:
		panic("%s: invalid cluster size %d", __func__, size);
	}

	return (type);
}

/*
 * Associated an external reference counted buffer with an mbuf.
 */
static __inline void
m_extaddref(struct mbuf *m, caddr_t buf, u_int size, u_int *ref_cnt,
    void (*freef)(struct mbuf *, void *, void *), void *arg1, void *arg2)
{

	KASSERT(ref_cnt != NULL, ("%s: ref_cnt not provided", __func__));

	atomic_add_int(ref_cnt, 1);
	m->m_flags |= M_EXT;
	m->m_ext.ext_buf = buf;
	m->m_ext.ext_cnt = ref_cnt;
	m->m_data = m->m_ext.ext_buf;
	m->m_ext.ext_size = size;
	m->m_ext.ext_free = freef;
	m->m_ext.ext_arg1 = arg1;
	m->m_ext.ext_arg2 = arg2;
	m->m_ext.ext_type = EXT_EXTREF;
	m->m_ext.ext_flags = 0;
}

static __inline uma_zone_t
m_getzone(int size)
{
	uma_zone_t zone;

	switch (size) {
	case MCLBYTES:
		zone = zone_clust;
		break;
#if MJUMPAGESIZE != MCLBYTES
	case MJUMPAGESIZE:
		zone = zone_jumbop;
		break;
#endif
	case MJUM9BYTES:
		zone = zone_jumbo9;
		break;
	case MJUM16BYTES:
		zone = zone_jumbo16;
		break;
	default:
		panic("%s: invalid cluster size %d", __func__, size);
	}

	return (zone);
}

/*
 * Initialize an mbuf with linear storage.
 *
 * Inline because the consumer text overhead will be roughly the same to
 * initialize or call a function with this many parameters and M_PKTHDR
 * should go away with constant propagation for !MGETHDR.
 */
static __inline int
m_init(struct mbuf *m, int how, short type, int flags)
{
	int error;

	m->m_next = NULL;
	m->m_nextpkt = NULL;
	m->m_data = m->m_dat;
	m->m_len = 0;
	m->m_flags = flags;
	m->m_type = type;
	if (flags & M_PKTHDR)
		error = m_pkthdr_init(m, how);
	else
		error = 0;

	MBUF_PROBE5(m__init, m, how, type, flags, error);
	return (error);
}

static __inline struct mbuf *
m_get(int how, short type)
{
	struct mbuf *m;
	struct mb_args args;

	args.flags = 0;
	args.type = type;
	m = uma_zalloc_arg(zone_mbuf, &args, how);
	MBUF_PROBE3(m__get, how, type, m);
	return (m);
}

static __inline struct mbuf *
m_gethdr(int how, short type)
{
	struct mbuf *m;
	struct mb_args args;

	args.flags = M_PKTHDR;
	args.type = type;
	m = uma_zalloc_arg(zone_mbuf, &args, how);
	MBUF_PROBE3(m__gethdr, how, type, m);
	return (m);
}

static __inline struct mbuf *
m_getcl(int how, short type, int flags)
{
	struct mbuf *m;
	struct mb_args args;

	args.flags = flags;
	args.type = type;
	m = uma_zalloc_arg(zone_pack, &args, how);
	MBUF_PROBE4(m__getcl, how, type, flags, m);
	return (m);
}

/*
 * XXX: m_cljset() is a dangerous API.  One must attach only a new,
 * unreferenced cluster to an mbuf(9).  It is not possible to assert
 * that, so care can be taken only by users of the API.
 */
static __inline void
m_cljset(struct mbuf *m, void *cl, int type)
{
	int size;

	switch (type) {
	case EXT_CLUSTER:
		size = MCLBYTES;
		break;
#if MJUMPAGESIZE != MCLBYTES
	case EXT_JUMBOP:
		size = MJUMPAGESIZE;
		break;
#endif
	case EXT_JUMBO9:
		size = MJUM9BYTES;
		break;
	case EXT_JUMBO16:
		size = MJUM16BYTES;
		break;
	default:
		panic("%s: unknown cluster type %d", __func__, type);
		break;
	}

	m->m_data = m->m_ext.ext_buf = cl;
	m->m_ext.ext_free = m->m_ext.ext_arg1 = m->m_ext.ext_arg2 = NULL;
	m->m_ext.ext_size = size;
	m->m_ext.ext_type = type;
	m->m_ext.ext_flags = EXT_FLAG_EMBREF;
	m->m_ext.ext_count = 1;
	m->m_flags |= M_EXT;
	MBUF_PROBE3(m__cljset, m, cl, type);
}

static __inline void
m_chtype(struct mbuf *m, short new_type)
{

	m->m_type = new_type;
}

static __inline void
m_clrprotoflags(struct mbuf *m)
{

	while (m) {
		m->m_flags &= ~M_PROTOFLAGS;
		m = m->m_next;
	}
}

static __inline struct mbuf *
m_last(struct mbuf *m)
{

	while (m->m_next)
		m = m->m_next;
	return (m);
}

static inline u_int
m_extrefcnt(struct mbuf *m)
{

	KASSERT(m->m_flags & M_EXT, ("%s: M_EXT missing", __func__));

	return ((m->m_ext.ext_flags & EXT_FLAG_EMBREF) ? m->m_ext.ext_count :
	    *m->m_ext.ext_cnt);
}

/*
 * mbuf, cluster, and external object allocation macros (for compatibility
 * purposes).
 */
#define	M_MOVE_PKTHDR(to, from)	m_move_pkthdr((to), (from))
#define	MGET(m, how, type)	((m) = m_get((how), (type)))
#define	MGETHDR(m, how, type)	((m) = m_gethdr((how), (type)))
#define	MCLGET(m, how)		m_clget((m), (how))
#define	MEXTADD(m, buf, size, free, arg1, arg2, flags, type)		\
    m_extadd((m), (caddr_t)(buf), (size), (free), (arg1), (arg2),	\
    (flags), (type))
#define	m_getm(m, len, how, type)					\
    m_getm2((m), (len), (how), (type), M_PKTHDR)

/*
 * Evaluate TRUE if it's safe to write to the mbuf m's data region (this can
 * be both the local data payload, or an external buffer area, depending on
 * whether M_EXT is set).
 */
#define	M_WRITABLE(m)	(!((m)->m_flags & M_RDONLY) &&			\
			 (!(((m)->m_flags & M_EXT)) ||			\
			 (m_extrefcnt(m) == 1)))

/* Check if the supplied mbuf has a packet header, or else panic. */
#define	M_ASSERTPKTHDR(m)						\
	KASSERT((m) != NULL && (m)->m_flags & M_PKTHDR,			\
	    ("%s: no mbuf packet header!", __func__))

/*
 * Ensure that the supplied mbuf is a valid, non-free mbuf.
 *
 * XXX: Broken at the moment.  Need some UMA magic to make it work again.
 */
#define	M_ASSERTVALID(m)						\
	KASSERT((((struct mbuf *)m)->m_flags & 0) == 0,			\
	    ("%s: attempted use of a free mbuf!", __func__))

/*
 * Return the address of the start of the buffer associated with an mbuf,
 * handling external storage, packet-header mbufs, and regular data mbufs.
 */
#define	M_START(m)							\
	(((m)->m_flags & M_EXT) ? (m)->m_ext.ext_buf :			\
	 ((m)->m_flags & M_PKTHDR) ? &(m)->m_pktdat[0] :		\
	 &(m)->m_dat[0])

/*
 * Return the size of the buffer associated with an mbuf, handling external
 * storage, packet-header mbufs, and regular data mbufs.
 */
#define	M_SIZE(m)							\
	(((m)->m_flags & M_EXT) ? (m)->m_ext.ext_size :			\
	 ((m)->m_flags & M_PKTHDR) ? MHLEN :				\
	 MLEN)

/*
 * Set the m_data pointer of a newly allocated mbuf to place an object of the
 * specified size at the end of the mbuf, longword aligned.
 *
 * NB: Historically, we had M_ALIGN(), MH_ALIGN(), and MEXT_ALIGN() as
 * separate macros, each asserting that it was called at the proper moment.
 * This required callers to themselves test the storage type and call the
 * right one.  Rather than require callers to be aware of those layout
 * decisions, we centralize here.
 */
static __inline void
m_align(struct mbuf *m, int len)
{
#ifdef INVARIANTS
	const char *msg = "%s: not a virgin mbuf";
#endif
	int adjust;

	KASSERT(m->m_data == M_START(m), (msg, __func__));

	adjust = M_SIZE(m) - len;
	m->m_data += adjust &~ (sizeof(long)-1);
}

#define	M_ALIGN(m, len)		m_align(m, len)
#define	MH_ALIGN(m, len)	m_align(m, len)
#define	MEXT_ALIGN(m, len)	m_align(m, len)

/*
 * Compute the amount of space available before the current start of data in
 * an mbuf.
 *
 * The M_WRITABLE() is a temporary, conservative safety measure: the burden
 * of checking writability of the mbuf data area rests solely with the caller.
 *
 * NB: In previous versions, M_LEADINGSPACE() would only check M_WRITABLE()
 * for mbufs with external storage.  We now allow mbuf-embedded data to be
 * read-only as well.
 */
#define	M_LEADINGSPACE(m)						\
	(M_WRITABLE(m) ? ((m)->m_data - M_START(m)) : 0)

/*
 * Compute the amount of space available after the end of data in an mbuf.
 *
 * The M_WRITABLE() is a temporary, conservative safety measure: the burden
 * of checking writability of the mbuf data area rests solely with the caller.
 *
 * NB: In previous versions, M_TRAILINGSPACE() would only check M_WRITABLE()
 * for mbufs with external storage.  We now allow mbuf-embedded data to be
 * read-only as well.
 */
#define	M_TRAILINGSPACE(m)						\
	(M_WRITABLE(m) ?						\
	    ((M_START(m) + M_SIZE(m)) - ((m)->m_data + (m)->m_len)) : 0)

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

/*
 * Change mbuf to new type.  This is a relatively expensive operation and
 * should be avoided.
 */
#define	MCHTYPE(m, t)	m_chtype((m), (t))

/* Length to m_copy to copy all. */
#define	M_COPYALL	1000000000

/* Compatibility with 4.3. */
#define	m_copy(m, o, l)	m_copym((m), (o), (l), M_NOWAIT)

extern int		max_datalen;	/* MHLEN - max_hdr */
extern int		max_hdr;	/* Largest link + protocol header */
extern int		max_linkhdr;	/* Largest link-level header */
extern int		max_protohdr;	/* Largest protocol header */
extern int		nmbclusters;	/* Maximum number of clusters */

/*-
 * Network packets may have annotations attached by affixing a list of
 * "packet tags" to the pkthdr structure.  Packet tags are dynamically
 * allocated semi-opaque data structures that have a fixed header
 * (struct m_tag) that specifies the size of the memory block and a
 * <cookie,type> pair that identifies it.  The cookie is a 32-bit unique
 * unsigned value used to identify a module or ABI.  By convention this value
 * is chosen as the date+time that the module is created, expressed as the
 * number of seconds since the epoch (e.g., using date -u +'%s').  The type
 * value is an ABI/module-specific value that identifies a particular
 * annotation and is private to the module.  For compatibility with systems
 * like OpenBSD that define packet tags w/o an ABI/module cookie, the value
 * PACKET_ABI_COMPAT is used to implement m_tag_get and m_tag_find
 * compatibility shim functions and several tag types are defined below.
 * Users that do not require compatibility should use a private cookie value
 * so that packet tag-related definitions can be maintained privately.
 *
 * Note that the packet tag returned by m_tag_alloc has the default memory
 * alignment implemented by malloc.  To reference private data one can use a
 * construct like:
 *
 *	struct m_tag *mtag = m_tag_alloc(...);
 *	struct foo *p = (struct foo *)(mtag+1);
 *
 * if the alignment of struct m_tag is sufficient for referencing members of
 * struct foo.  Otherwise it is necessary to embed struct m_tag within the
 * private data structure to insure proper alignment; e.g.,
 *
 *	struct foo {
 *		struct m_tag	tag;
 *		...
 *	};
 *	struct foo *p = (struct foo *) m_tag_alloc(...);
 *	struct m_tag *mtag = &p->tag;
 */

/*
 * Persistent tags stay with an mbuf until the mbuf is reclaimed.  Otherwise
 * tags are expected to ``vanish'' when they pass through a network
 * interface.  For most interfaces this happens normally as the tags are
 * reclaimed when the mbuf is free'd.  However in some special cases
 * reclaiming must be done manually.  An example is packets that pass through
 * the loopback interface.  Also, one must be careful to do this when
 * ``turning around'' packets (e.g., icmp_reflect).
 *
 * To mark a tag persistent bit-or this flag in when defining the tag id.
 * The tag will then be treated as described above.
 */
#define	MTAG_PERSISTENT				0x800

#define	PACKET_TAG_NONE				0  /* Nadda */

/* Packet tags for use with PACKET_ABI_COMPAT. */
#define	PACKET_TAG_IPSEC_IN_DONE		1  /* IPsec applied, in */
#define	PACKET_TAG_IPSEC_OUT_DONE		2  /* IPsec applied, out */
#define	PACKET_TAG_IPSEC_IN_CRYPTO_DONE		3  /* NIC IPsec crypto done */
#define	PACKET_TAG_IPSEC_OUT_CRYPTO_NEEDED	4  /* NIC IPsec crypto req'ed */
#define	PACKET_TAG_IPSEC_IN_COULD_DO_CRYPTO	5  /* NIC notifies IPsec */
#define	PACKET_TAG_IPSEC_PENDING_TDB		6  /* Reminder to do IPsec */
#define	PACKET_TAG_BRIDGE			7  /* Bridge processing done */
#define	PACKET_TAG_GIF				8  /* GIF processing done */
#define	PACKET_TAG_GRE				9  /* GRE processing done */
#define	PACKET_TAG_IN_PACKET_CHECKSUM		10 /* NIC checksumming done */
#define	PACKET_TAG_ENCAP			11 /* Encap.  processing */
#define	PACKET_TAG_IPSEC_SOCKET			12 /* IPSEC socket ref */
#define	PACKET_TAG_IPSEC_HISTORY		13 /* IPSEC history */
#define	PACKET_TAG_IPV6_INPUT			14 /* IPV6 input processing */
#define	PACKET_TAG_DUMMYNET			15 /* dummynet info */
#define	PACKET_TAG_DIVERT			17 /* divert info */
#define	PACKET_TAG_IPFORWARD			18 /* ipforward info */
#define	PACKET_TAG_MACLABEL	(19 | MTAG_PERSISTENT) /* MAC label */
#define	PACKET_TAG_PF		(21 | MTAG_PERSISTENT) /* PF/ALTQ information */
#define	PACKET_TAG_RTSOCKFAM			25 /* rtsock sa family */
#define	PACKET_TAG_IPOPTIONS			27 /* Saved IP options */
#define	PACKET_TAG_CARP				28 /* CARP info */
#define	PACKET_TAG_IPSEC_NAT_T_PORTS		29 /* two uint16_t */
#define	PACKET_TAG_ND_OUTGOING			30 /* ND outgoing */

/* Specific cookies and tags. */

/* Packet tag routines. */
struct m_tag	*m_tag_alloc(u_int32_t, int, int, int);
void		 m_tag_delete(struct mbuf *, struct m_tag *);
void		 m_tag_delete_chain(struct mbuf *, struct m_tag *);
void		 m_tag_free_default(struct m_tag *);
struct m_tag	*m_tag_locate(struct mbuf *, u_int32_t, int, struct m_tag *);
struct m_tag	*m_tag_copy(struct m_tag *, int);
int		 m_tag_copy_chain(struct mbuf *, const struct mbuf *, int);
void		 m_tag_delete_nonpersistent(struct mbuf *);

/*
 * Initialize the list of tags associated with an mbuf.
 */
static __inline void
m_tag_init(struct mbuf *m)
{

	SLIST_INIT(&m->m_pkthdr.tags);
}

/*
 * Set up the contents of a tag.  Note that this does not fill in the free
 * method; the caller is expected to do that.
 *
 * XXX probably should be called m_tag_init, but that was already taken.
 */
static __inline void
m_tag_setup(struct m_tag *t, u_int32_t cookie, int type, int len)
{

	t->m_tag_id = type;
	t->m_tag_len = len;
	t->m_tag_cookie = cookie;
}

/*
 * Reclaim resources associated with a tag.
 */
static __inline void
m_tag_free(struct m_tag *t)
{

	(*t->m_tag_free)(t);
}

/*
 * Return the first tag associated with an mbuf.
 */
static __inline struct m_tag *
m_tag_first(struct mbuf *m)
{

	return (SLIST_FIRST(&m->m_pkthdr.tags));
}

/*
 * Return the next tag in the list of tags associated with an mbuf.
 */
static __inline struct m_tag *
m_tag_next(struct mbuf *m __unused, struct m_tag *t)
{

	return (SLIST_NEXT(t, m_tag_link));
}

/*
 * Prepend a tag to the list of tags associated with an mbuf.
 */
static __inline void
m_tag_prepend(struct mbuf *m, struct m_tag *t)
{

	SLIST_INSERT_HEAD(&m->m_pkthdr.tags, t, m_tag_link);
}

/*
 * Unlink a tag from the list of tags associated with an mbuf.
 */
static __inline void
m_tag_unlink(struct mbuf *m, struct m_tag *t)
{

	SLIST_REMOVE(&m->m_pkthdr.tags, t, m_tag, m_tag_link);
}

/* These are for OpenBSD compatibility. */
#define	MTAG_ABI_COMPAT		0		/* compatibility ABI */

static __inline struct m_tag *
m_tag_get(int type, int length, int wait)
{
	return (m_tag_alloc(MTAG_ABI_COMPAT, type, length, wait));
}

static __inline struct m_tag *
m_tag_find(struct mbuf *m, int type, struct m_tag *start)
{
	return (SLIST_EMPTY(&m->m_pkthdr.tags) ? (struct m_tag *)NULL :
	    m_tag_locate(m, MTAG_ABI_COMPAT, type, start));
}

static __inline struct mbuf *
m_free(struct mbuf *m)
{
	struct mbuf *n = m->m_next;

	MBUF_PROBE1(m__free, m);
	if ((m->m_flags & (M_PKTHDR|M_NOFREE)) == (M_PKTHDR|M_NOFREE))
		m_tag_delete_chain(m, NULL);
	if (m->m_flags & M_EXT)
		mb_free_ext(m);
	else if ((m->m_flags & M_NOFREE) == 0)
		uma_zfree(zone_mbuf, m);
	return (n);
}

static __inline int
rt_m_getfib(struct mbuf *m)
{
	KASSERT(m->m_flags & M_PKTHDR , ("Attempt to get FIB from non header mbuf."));
	return (m->m_pkthdr.fibnum);
}

#define M_GETFIB(_m)   rt_m_getfib(_m)

#define M_SETFIB(_m, _fib) do {						\
        KASSERT((_m)->m_flags & M_PKTHDR, ("Attempt to set FIB on non header mbuf."));	\
	((_m)->m_pkthdr.fibnum) = (_fib);				\
} while (0)

/* flags passed as first argument for "m_ether_tcpip_hash()" */
#define	MBUF_HASHFLAG_L2	(1 << 2)
#define	MBUF_HASHFLAG_L3	(1 << 3)
#define	MBUF_HASHFLAG_L4	(1 << 4)

/* mbuf hashing helper routines */
uint32_t	m_ether_tcpip_hash_init(void);
uint32_t	m_ether_tcpip_hash(const uint32_t, const struct mbuf *, const uint32_t);

#ifdef MBUF_PROFILING
 void m_profile(struct mbuf *m);
 #define M_PROFILE(m) m_profile(m)
#else
 #define M_PROFILE(m)
#endif

struct mbufq {
	STAILQ_HEAD(, mbuf)	mq_head;
	int			mq_len;
	int			mq_maxlen;
};

static inline void
mbufq_init(struct mbufq *mq, int maxlen)
{

	STAILQ_INIT(&mq->mq_head);
	mq->mq_maxlen = maxlen;
	mq->mq_len = 0;
}

static inline struct mbuf *
mbufq_flush(struct mbufq *mq)
{
	struct mbuf *m;

	m = STAILQ_FIRST(&mq->mq_head);
	STAILQ_INIT(&mq->mq_head);
	mq->mq_len = 0;
	return (m);
}

static inline void
mbufq_drain(struct mbufq *mq)
{
	struct mbuf *m, *n;

	n = mbufq_flush(mq);
	while ((m = n) != NULL) {
		n = STAILQ_NEXT(m, m_stailqpkt);
		m_freem(m);
	}
}

static inline struct mbuf *
mbufq_first(const struct mbufq *mq)
{

	return (STAILQ_FIRST(&mq->mq_head));
}

static inline struct mbuf *
mbufq_last(const struct mbufq *mq)
{

	return (STAILQ_LAST(&mq->mq_head, mbuf, m_stailqpkt));
}

static inline int
mbufq_full(const struct mbufq *mq)
{

	return (mq->mq_len >= mq->mq_maxlen);
}

static inline int
mbufq_len(const struct mbufq *mq)
{

	return (mq->mq_len);
}

static inline int
mbufq_enqueue(struct mbufq *mq, struct mbuf *m)
{

	if (mbufq_full(mq))
		return (ENOBUFS);
	STAILQ_INSERT_TAIL(&mq->mq_head, m, m_stailqpkt);
	mq->mq_len++;
	return (0);
}

static inline struct mbuf *
mbufq_dequeue(struct mbufq *mq)
{
	struct mbuf *m;

	m = STAILQ_FIRST(&mq->mq_head);
	if (m) {
		STAILQ_REMOVE_HEAD(&mq->mq_head, m_stailqpkt);
		m->m_nextpkt = NULL;
		mq->mq_len--;
	}
	return (m);
}

static inline void
mbufq_prepend(struct mbufq *mq, struct mbuf *m)
{

	STAILQ_INSERT_HEAD(&mq->mq_head, m, m_stailqpkt);
	mq->mq_len++;
}
#endif /* _KERNEL */
#endif /* !_SYS_MBUF_H_ */