/*      $OpenBSD: mbuf.h,v 1.269 2026/02/05 03:26:00 dlg Exp $  */
/*      $NetBSD: mbuf.h,v 1.19 1996/02/09 18:25:14 christos Exp $       */

/*
 * 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_

#include <sys/queue.h>

/*
 * Constants related to network buffer management.
 * MCLBYTES must be no larger than PAGE_SIZE (the software page size) and,
 * on machines that exchange pages of input or output buffers with mbuf
 * clusters (MAPPED_MBUFS), MCLBYTES must also be an integral multiple
 * of the hardware page size.
 */
#define MSIZE           256             /* size of an mbuf */

/*
 * Mbufs are of a single size, MSIZE, which includes overhead.  An mbuf may
 * add a single "mbuf cluster" of size MCLBYTES, 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 MAXMCLBYTES     (64 * 1024)             /* largest cluster from the stack */
#define MINCLSIZE       (MHLEN + MLEN + 1)      /* smallest amount to put in cluster */

#define MCLSHIFT        11              /* convert bytes to m_buf clusters */
                                        /* 2K cluster can hold Ether frame */
#define MCLBYTES        (1 << MCLSHIFT) /* size of a m_buf cluster */

/* Packet tags structure */
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 */
};

/*
 * 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 */
        caddr_t mh_data;                /* location of data */
        u_int   mh_len;                 /* amount of data in this mbuf */
        short   mh_type;                /* type of data in this mbuf */
        u_short mh_flags;               /* flags; see below */
#ifndef __LP64__
        u_int   mh_pad;                 /* pad to 8-byte boundary */
#endif
};

/* pf stuff */
struct pf_state_key;
struct inpcb;

struct pkthdr_pf {
        struct pf_state_key *statekey;  /* pf stackside statekey */
        struct inpcb    *inp;           /* connected pcb for outgoing packet */
        u_int32_t        qid;           /* queue id */
        u_int16_t        tag;           /* tag id */
        u_int16_t        delay;         /* delay packet by X ms */
        u_int8_t         flags;
        u_int8_t         routed;
        u_int8_t         prio;
        u_int8_t         pad[1];
};

/* pkthdr_pf.flags */
#define PF_TAG_GENERATED                0x01
#define PF_TAG_SYNCOOKIE_RECREATED      0x02
#define PF_TAG_TRANSLATE_LOCALHOST      0x04
#define PF_TAG_DIVERTED                 0x08
#define PF_TAG_DIVERTED_PACKET          0x10
#define PF_TAG_REROUTE                  0x20
#define PF_TAG_REFRAGMENTED             0x40    /* refragmented ipv6 packet */
#define PF_TAG_PROCESSED                0x80    /* packet was checked by pf */

#ifdef _KERNEL
#define MPF_BITS \
    ("\20\1GENERATED\2SYNCOOKIE_RECREATED\3TRANSLATE_LOCALHOST\4DIVERTED" \
    "\5DIVERTED_PACKET\6REROUTE\7REFRAGMENTED\10PROCESSED")
#endif

/* record/packet header in first mbuf of chain; valid if M_PKTHDR set */
struct  pkthdr {
        void                    *ph_cookie;     /* additional data */
        SLIST_HEAD(, m_tag)      ph_tags;       /* list of packet tags */
        int64_t                  ph_timestamp;  /* packet timestamp */
        int                      len;           /* total packet length */
        u_int                    ph_rtableid;   /* routing table id */
        u_int                    ph_ifidx;      /* rcv interface index */
        u_int16_t                ph_tagsset;    /* mtags attached */
        u_int16_t                ph_flowid;     /* pseudo unique flow id */
        u_int16_t                csum_flags;    /* checksum flags */
        u_int16_t                ether_vtag;    /* Ethernet 802.1p+Q vlan tag */
        u_int16_t                ph_mss;        /* TCP max segment size */
        u_int8_t                 ph_loopcnt;    /* mbuf is looping in kernel */
        u_int8_t                 ph_family;     /* af, used when queueing */
        struct pkthdr_pf         pf;
};

/* description of external storage mapped into mbuf, valid if M_EXT set */
struct mbuf_ext {
        caddr_t ext_buf;                /* start of buffer */
        void    *ext_arg;
        u_int   ext_free_fn;            /* index of free function */
        u_int   ext_size;               /* size of buffer, for ext_free_fn */
        struct mbuf *ext_nextref;
        struct mbuf *ext_prevref;
#ifdef DEBUG
        const char *ext_ofile;
        const char *ext_nfile;
        int ext_oline;
        int ext_nline;
#endif
};

struct mbuf {
        struct  m_hdr m_hdr;
        union {
                struct {
                        struct  pkthdr MH_pkthdr;       /* M_PKTHDR set */
                        union {
                                struct  mbuf_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_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_EXTWR         0x0008  /* external storage is writable */
#define M_PROTO1        0x0010  /* protocol-specific */

/* mbuf pkthdr flags, also in m_flags */
#define M_VLANTAG       0x0020  /* ether_vtag is valid */
#define M_LOOP          0x0040  /* packet has been sent from local machine */
#define M_BCAST         0x0100  /* sent/received as link-level broadcast */
#define M_MCAST         0x0200  /* sent/received as link-level multicast */
#define M_CONF          0x0400  /* payload was encrypted (ESP-transport) */
#define M_AUTH          0x0800  /* payload was authenticated (AH or ESP auth) */
#define M_TUNNEL        0x1000  /* IP-in-IP added by tunnel mode IPsec */
#define M_ZEROIZE       0x2000  /* Zeroize data part on free */
#define M_COMP          0x4000  /* header was decompressed */
#define M_LINK0         0x8000  /* link layer specific flag */

#ifdef _KERNEL
#define M_BITS \
    ("\20\1M_EXT\2M_PKTHDR\3M_EOR\4M_EXTWR\5M_PROTO1\6M_VLANTAG\7M_LOOP" \
    "\11M_BCAST\12M_MCAST\13M_CONF\14M_AUTH\15M_TUNNEL" \
    "\16M_ZEROIZE\17M_COMP\20M_LINK0")
#endif

/* flags copied when copying m_pkthdr */
#define M_COPYFLAGS     (M_PKTHDR|M_EOR|M_PROTO1|M_BCAST|M_MCAST|M_CONF|M_COMP|\
                         M_AUTH|M_LOOP|M_TUNNEL|M_LINK0|M_VLANTAG|M_ZEROIZE)

/* Checksumming flags */
#define M_IPV4_CSUM_OUT         0x0001  /* IPv4 checksum needed */
#define M_TCP_CSUM_OUT          0x0002  /* TCP checksum needed */
#define M_UDP_CSUM_OUT          0x0004  /* UDP checksum needed */
#define M_IPV4_CSUM_IN_OK       0x0008  /* IPv4 checksum verified */
#define M_IPV4_CSUM_IN_BAD      0x0010  /* IPv4 checksum bad */
#define M_TCP_CSUM_IN_OK        0x0020  /* TCP checksum verified */
#define M_TCP_CSUM_IN_BAD       0x0040  /* TCP checksum bad */
#define M_UDP_CSUM_IN_OK        0x0080  /* UDP checksum verified */
#define M_UDP_CSUM_IN_BAD       0x0100  /* UDP checksum bad */
#define M_ICMP_CSUM_OUT         0x0200  /* ICMP/ICMPv6 checksum needed */
#define M_ICMP_CSUM_IN_OK       0x0400  /* ICMP/ICMPv6 checksum verified */
#define M_ICMP_CSUM_IN_BAD      0x0800  /* ICMP/ICMPv6 checksum bad */
#define M_IPV6_DF_OUT           0x1000  /* don't fragment outgoing IPv6 */
#define M_TIMESTAMP             0x2000  /* ph_timestamp is set */
#define M_FLOWID                0x4000  /* ph_flowid is set */
#define M_TCP_TSO               0x8000  /* TCP Segmentation Offload needed */

#ifdef _KERNEL
#define MCS_BITS \
    ("\20\1IPV4_CSUM_OUT\2TCP_CSUM_OUT\3UDP_CSUM_OUT\4IPV4_CSUM_IN_OK" \
    "\5IPV4_CSUM_IN_BAD\6TCP_CSUM_IN_OK\7TCP_CSUM_IN_BAD\10UDP_CSUM_IN_OK" \
    "\11UDP_CSUM_IN_BAD\12ICMP_CSUM_OUT\13ICMP_CSUM_IN_OK\14ICMP_CSUM_IN_BAD" \
    "\15IPV6_NODF_OUT" "\16TIMESTAMP" "\17FLOWID" "\20TCP_TSO")
#endif

/* 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  */
#define MT_NTYPES       8

/* flags to m_get/MGET */
#include <sys/malloc.h>
#define M_DONTWAIT      M_NOWAIT
#define M_WAIT          M_WAITOK

/*
 * 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) m = m_get((how), (type))

#define MGETHDR(m, how, type) m = m_gethdr((how), (type))

/*
 * 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 MCLISREFERENCED(m)      ((m)->m_ext.ext_nextref != (m))

#define MCLADDREFERENCE(o, n)   m_extref((o), (n))

#define MCLINITREFERENCE(m)     do {                                    \
                (m)->m_ext.ext_prevref = (m);                           \
                (m)->m_ext.ext_nextref = (m);                           \
                MCLREFDEBUGO((m), __FILE__, __LINE__);                  \
                MCLREFDEBUGN((m), NULL, 0);                             \
        } while (/* CONSTCOND */ 0)

/*
 * Macros for mbuf external storage.
 *
 * MEXTADD adds pre-allocated external storage to
 * a normal mbuf; the flag M_EXT is set.
 *
 * MCLGET allocates and adds an mbuf cluster to a normal mbuf;
 * the flag M_EXT is set upon success.
 */
#define MEXTADD(m, buf, size, mflags, freefn, arg) do {                 \
        (m)->m_data = (m)->m_ext.ext_buf = (caddr_t)(buf);              \
        (m)->m_flags |= M_EXT | (mflags & M_EXTWR);                     \
        (m)->m_ext.ext_size = (size);                                   \
        (m)->m_ext.ext_free_fn = (freefn);                                      \
        (m)->m_ext.ext_arg = (arg);                                     \
        MCLINITREFERENCE(m);                                            \
} while (/* CONSTCOND */ 0)

#define MCLGET(m, how) (void) m_clget((m), (how), MCLBYTES)
#define MCLGETL(m, how, l) m_clget((m), (how), (l))

u_int mextfree_register(void (*)(caddr_t, u_int, void *));
#define MEXTFREE_POOL 0

/*
 * Move just m_pkthdr from from to to,
 * remove M_PKTHDR and clean flags/tags for from.
 */
#define M_MOVE_HDR(to, from) do {                                       \
        (to)->m_pkthdr = (from)->m_pkthdr;                              \
        (from)->m_flags &= ~M_PKTHDR;                                   \
        SLIST_INIT(&(from)->m_pkthdr.ph_tags);                          \
        (from)->m_pkthdr.pf.statekey = NULL;                            \
} 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) do {                                    \
        (to)->m_flags = ((to)->m_flags & (M_EXT | M_EXTWR));            \
        (to)->m_flags |= (from)->m_flags & M_COPYFLAGS;                 \
        M_MOVE_HDR((to), (from));                                       \
        if (((to)->m_flags & M_EXT) == 0)                               \
                (to)->m_data = (to)->m_pktdat;                          \
} while (/* CONSTCOND */ 0)

/*
 * Determine if an mbuf's data area is read-only. This is true for
 * non-cluster external storage and for clusters that are being
 * referenced by more than one mbuf.
 */
#define M_READONLY(m)                                                   \
        (((m)->m_flags & M_EXT) != 0 &&                                 \
          (((m)->m_flags & M_EXTWR) == 0 || MCLISREFERENCED(m)))

/*
 * 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) \
                (m) = m_prepend((m), (plen), (how))

/* length to m_copy to copy all */
#define M_COPYALL       1000000000

enum mbstat_counters {
        mbs_drops = MT_NTYPES,
        mbs_wait,
        mbs_drain,
        mbs_defrag_alloc,
        mbs_prepend_alloc,
        mbs_pullup_alloc,
        mbs_pullup_copy,
        mbs_pulldown_alloc,
        mbs_pulldown_copy,
        mbs_ncounters
};

/*
 * Mbuf statistics.
 * For statistics related to mbuf and cluster allocations, see also the
 * pool headers (mbpool and mclpool).
 */
struct mbstat {
        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_mtypes[MT_NTYPES];    /* type specific mbuf allocations */
        u_long  m_defrag_alloc;
        u_long  m_prepend_alloc;
        u_long  m_pullup_alloc;
        u_long  m_pullup_copy;
        u_long  m_pulldown_alloc;
        u_long  m_pulldown_copy;
};

#include <sys/mutex.h>

struct mbuf_list {
        struct mbuf             *ml_head;
        struct mbuf             *ml_tail;
        u_int                   ml_len;
};

struct mbuf_queue {
        struct mutex            mq_mtx;
        struct mbuf_list        mq_list;
        u_int                   mq_maxlen;
        u_int                   mq_drops;
};

#ifdef  _KERNEL
struct pool;

extern  long nmbclust;                  /* limit on the # of clusters */
extern  int max_linkhdr;                /* largest link-level header */
extern  int max_protohdr;               /* largest protocol header */
extern  int max_hdr;                    /* largest link+protocol header */
extern  struct cpumem *mbstat;          /* mbuf statistics counter */

void    mbinit(void);
void    mbcpuinit(void);
int     nmbclust_update(long);
struct  mbuf *m_copym(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_inithdr(struct mbuf *);
void    m_removehdr(struct mbuf *);
void    m_resethdr(struct mbuf *);
void    m_calchdrlen(struct mbuf *);
int     m_defrag(struct mbuf *, 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_split(struct mbuf *, int, int);
struct  mbuf *m_makespace(struct mbuf *, int, int, int *);
struct  mbuf *m_getptr(struct mbuf *, int, int *);
int     m_leadingspace(struct mbuf *);
int     m_trailingspace(struct mbuf *);
void    m_align(struct mbuf *, int);
struct mbuf *m_clget(struct mbuf *, int, u_int);
void    m_extref(struct mbuf *, struct mbuf *);
void    m_pool_init(struct pool *, u_int, u_int, const char *);
u_int   m_pool_used(void);
void    m_extfree_pool(caddr_t, u_int, void *);
void    m_adj(struct mbuf *, int);
int     m_copyback(struct mbuf *, int, int, const void *, int);
struct mbuf *m_freem(struct mbuf *);
void    m_purge(struct mbuf *);
void    m_copydata(struct mbuf *, int, int, void *);
void    m_cat(struct mbuf *, struct mbuf *);
struct mbuf *m_devget(char *, int, int);
int     m_apply(struct mbuf *, int, int,
            int (*)(caddr_t, caddr_t, unsigned int), caddr_t);
struct mbuf *m_dup_pkt(struct mbuf *, unsigned int, int);
int     m_dup_pkthdr(struct mbuf *, struct mbuf *, int);

void    m_microtime(const struct mbuf *, struct timeval *);

static inline struct mbuf *
m_freemp(struct mbuf **mp)
{
        struct mbuf *m = *mp;

        *mp = NULL;
        return m_freem(m);
}

#include <sys/percpu.h>

static inline void
mbstat_inc(enum mbstat_counters c)
{
        int s = splnet();
        counters_inc(mbstat, c);
        splx(s);
}

/* Packet tag routines */
struct m_tag *m_tag_get(int, int, int);
void    m_tag_prepend(struct mbuf *, struct m_tag *);
void    m_tag_delete(struct mbuf *, struct m_tag *);
void    m_tag_delete_chain(struct mbuf *);
struct m_tag *m_tag_find(struct mbuf *, int, struct m_tag *);
struct m_tag *m_tag_copy(struct m_tag *, int);
int     m_tag_copy_chain(struct mbuf *, struct mbuf *, int);
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_IPSEC_IN_DONE        0x0001  /* IPsec applied, in */
#define PACKET_TAG_IPSEC_OUT_DONE       0x0002  /* IPsec applied, out */
#define PACKET_TAG_IPSEC_FLOWINFO       0x0004  /* IPsec flowinfo */
#define PACKET_TAG_IP_OFFNXT            0x0010  /* IPv4 offset and next proto */
#define PACKET_TAG_IP6_OFFNXT           0x0020  /* IPv6 offset and next proto */
#define PACKET_TAG_WIREGUARD            0x0040  /* WireGuard data */
#define PACKET_TAG_GRE                  0x0080  /* GRE processing done */
#define PACKET_TAG_DLT                  0x0100 /* data link layer type */
#define PACKET_TAG_PF_DIVERT            0x0200 /* pf(4) diverted packet */
#define PACKET_TAG_PF_REASSEMBLED       0x0800 /* pf reassembled ipv6 packet */
#define PACKET_TAG_SRCROUTE             0x1000 /* IPv4 source routing options */
#define PACKET_TAG_TUNNEL               0x2000  /* Tunnel endpoint address */
#define PACKET_TAG_CARP_BAL_IP          0x4000  /* carp(4) ip balanced marker */

#define MTAG_BITS \
    ("\20\1IPSEC_IN_DONE\2IPSEC_OUT_DONE\3IPSEC_FLOWINFO" \
    "\4IPSEC_OUT_CRYPTO_NEEDED\5IPSEC_PENDING_TDB\6BRIDGE\7WG\10GRE\11DLT" \
    "\12PF_DIVERT\14PF_REASSEMBLED\15SRCROUTE\16TUNNEL\17CARP_BAL_IP")

/*
 * Maximum tag payload length (that is excluding the m_tag structure).
 * Please make sure to update this value when increasing the payload
 * length for an existing packet tag type or when adding a new one that
 * has payload larger than the value below.
 */
#define PACKET_TAG_MAXSIZE              80

/* Detect mbufs looping in the kernel when spliced too often. */
#define M_MAXLOOP       128

/*
 * mbuf lists
 */

#define MBUF_LIST_INITIALIZER() { NULL, NULL, 0 }

void                    ml_init(struct mbuf_list *);
void                    ml_enqueue(struct mbuf_list *, struct mbuf *);
struct mbuf *           ml_dequeue(struct mbuf_list *);
void                    ml_enlist(struct mbuf_list *, struct mbuf_list *);
struct mbuf *           ml_dechain(struct mbuf_list *);
unsigned int            ml_purge(struct mbuf_list *);
unsigned int            ml_hdatalen(struct mbuf_list *);

#define ml_len(_ml)             ((_ml)->ml_len)
#define ml_empty(_ml)           ((_ml)->ml_len == 0)

#define MBUF_LIST_FIRST(_ml)    ((_ml)->ml_head)
#define MBUF_LIST_NEXT(_m)      ((_m)->m_nextpkt)

#define MBUF_LIST_FOREACH(_ml, _m)                                      \
        for ((_m) = MBUF_LIST_FIRST(_ml);                               \
            (_m) != NULL;                                               \
            (_m) = MBUF_LIST_NEXT(_m))

/*
 * mbuf queues
 */

#include <sys/atomic.h>

#define MBUF_QUEUE_INITIALIZER(_maxlen, _ipl) \
    { MUTEX_INITIALIZER(_ipl), MBUF_LIST_INITIALIZER(), (_maxlen), 0 }

void                    mq_init(struct mbuf_queue *, u_int, int);
int                     mq_push(struct mbuf_queue *, struct mbuf *);
int                     mq_enqueue(struct mbuf_queue *, struct mbuf *);
struct mbuf *           mq_dequeue(struct mbuf_queue *);
int                     mq_enlist(struct mbuf_queue *, struct mbuf_list *);
void                    mq_delist(struct mbuf_queue *, struct mbuf_list *);
unsigned int            mq_purge(struct mbuf_queue *);
unsigned int            mq_hdatalen(struct mbuf_queue *);
void                    mq_set_maxlen(struct mbuf_queue *, u_int);

#define mq_len(_mq)             READ_ONCE((_mq)->mq_list.ml_len)
#define mq_empty(_mq)           (mq_len(_mq) == 0)
#define mq_full(_mq)            (mq_len((_mq)) >= READ_ONCE((_mq)->mq_maxlen))
#define mq_drops(_mq)           READ_ONCE((_mq)->mq_drops)

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