KTLS: Re-work unmapped mbufs to carry ext_pgs in the mbuf itself.

[FreeBSD/FreeBSD.git] / sys / sys / mbuf.h

/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * 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
 * $FreeBSD$
 */

#ifndef _SYS_MBUF_H_
#define _SYS_MBUF_H_

/* XXX: These includes suck. Sorry! */
#include <sys/queue.h>
#ifdef _KERNEL
#include <sys/systm.h>
#include <sys/refcount.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)
#define M_NODOM         255

#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 *);
};

/*
 * Static network interface owned tag.
 * Allocated through ifp->if_snd_tag_alloc().
 */
struct m_snd_tag {
        struct ifnet *ifp;              /* network interface tag belongs to */
        volatile u_int refcount;
};

/*
 * 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 {
        union {
                struct m_snd_tag *snd_tag;      /* send tag, if any */
                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 */
        uint32_t         csum_flags;    /* checksum and offload features */
        uint16_t         fibnum;        /* this packet should use this fib */
        uint8_t          numa_domain;   /* NUMA domain of recvd pkt */
        uint8_t          rsstype;       /* hash type */
        union {
                uint64_t        rcv_tstmp;      /* timestamp in ns */
                struct {
                        uint8_t          l2hlen;        /* layer 2 hdr len */
                        uint8_t          l3hlen;        /* layer 3 hdr len */
                        uint8_t          l4hlen;        /* layer 4 hdr len */
                        uint8_t          l5hlen;        /* layer 5 hdr len */
                        uint32_t         spare;
                };
        };
        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]        /* mld and v6-ND */
#define tso_segsz       PH_per.sixteen[1] /* inbound after LRO */
#define lro_nsegs       tso_segsz         /* inbound after LRO */
#define csum_data       PH_per.thirtytwo[1] /* inbound from hardware up */
#define lro_len         PH_loc.sixteen[0] /* inbound during LRO (no reassembly) */
#define lro_csum        PH_loc.sixteen[1] /* inbound during LRO (no reassembly) */
/* Note PH_loc is used during IP reassembly (all 8 bytes as a ptr) */

/*
 * TLS records for TLS 1.0-1.2 can have the following header lengths:
 * - 5 (AES-CBC with implicit IV)
 * - 21 (AES-CBC with explicit IV)
 * - 13 (AES-GCM with 8 byte explicit IV)
 */
#define MBUF_PEXT_HDR_LEN       23

/*
 * TLS records for TLS 1.0-1.2 can have the following maximum trailer
 * lengths:
 * - 16 (AES-GCM)
 * - 36 (AES-CBC with SHA1 and up to 16 bytes of padding)
 * - 48 (AES-CBC with SHA2-256 and up to 16 bytes of padding)
 * - 64 (AES-CBC with SHA2-384 and up to 16 bytes of padding)
 */
#define MBUF_PEXT_TRAIL_LEN     64

#if defined(__LP64__)
#define MBUF_PEXT_MAX_PGS (40 / sizeof(vm_paddr_t))
#else
#define MBUF_PEXT_MAX_PGS (72 / sizeof(vm_paddr_t))
#endif

#define MBUF_PEXT_MAX_BYTES                                             \
    (MBUF_PEXT_MAX_PGS * PAGE_SIZE + MBUF_PEXT_HDR_LEN + MBUF_PEXT_TRAIL_LEN)

#define MBUF_PEXT_FLAG_ANON     1       /* Data can be encrypted in place. */


struct mbuf_ext_pgs_data {
        vm_paddr_t      pa[MBUF_PEXT_MAX_PGS];          /* phys addrs of pgs */
        char            trail[MBUF_PEXT_TRAIL_LEN];     /* TLS trailer */
        char            hdr[MBUF_PEXT_HDR_LEN];         /* TLS header */
};

struct ktls_session;
struct socket;

/*
 * 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.
 */
typedef void m_ext_free_t(struct mbuf *);
struct m_ext {
        union {
                /*
                 * If EXT_FLAG_EMBREF is set, then we use refcount in the
                 * mbuf, the 'ext_count' member.  Otherwise, we have a
                 * shadow copy and we use pointer 'ext_cnt'.  The original
                 * mbuf is responsible to carry the pointer to free routine
                 * and its arguments.  They aren't copied into shadows in
                 * mb_dupcl() to avoid dereferencing next cachelines.
                 */
                volatile u_int   ext_count;
                volatile u_int  *ext_cnt;
        };
        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 */
        char            *ext_buf;       /* start of buffer */
        /*
         * Fields below store the free context for the external storage.
         * They are valid only in the refcount carrying mbuf, the one with
         * EXT_FLAG_EMBREF flag, with exclusion for EXT_EXTREF type, where
         * the free context is copied into all mbufs that use same external
         * storage.
         */
#define m_ext_copylen   offsetof(struct m_ext, ext_free)
        m_ext_free_t    *ext_free;      /* free routine if not the usual */
        void            *ext_arg1;      /* optional argument pointer */
        union {
                void            *ext_arg2;      /* optional argument pointer */
                struct mbuf_ext_pgs_data ext_pgs;
        };
};

struct mbuf_ext_pgs {
        uint8_t         npgs;                   /* Number of attached pages */
        uint8_t         nrdy;                   /* Pages with I/O pending */
        uint8_t         hdr_len;                /* TLS header length */
        uint8_t         trail_len;              /* TLS trailer length */
        uint16_t        first_pg_off;           /* Offset into 1st page */
        uint16_t        last_pg_len;            /* Length of last page */
        uint8_t         flags;                  /* Flags */
        uint8_t         record_type;
        uint8_t         spare[2];
        int             enc_cnt;
        struct ktls_session *tls;               /* TLS session */
        struct socket   *so;
        uint64_t        seqno;
        struct mbuf     *mbuf;
        STAILQ_ENTRY(mbuf_ext_pgs) stailq;
#if !defined(__LP64__)
        uint8_t         pad[8];         /* pad to size of pkthdr */
#endif
        struct m_ext    m_ext;
};

#define m_epg_hdr       m_ext.ext_pgs.hdr
#define m_epg_trail     m_ext.ext_pgs.trail
#define m_epg_pa        m_ext.ext_pgs.pa

/*
 * 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 {
                union {
                        struct {
                                struct pkthdr   m_pkthdr; /* M_PKTHDR set */
                                union {
                                        struct m_ext    m_ext;  /* M_EXT set */
                                        char            m_pktdat[0];
                                };
                        };
                        struct mbuf_ext_pgs m_ext_pgs;
                };
                char    m_dat[0];                       /* !M_PKTHDR, !M_EXT */
        };
};

#ifdef _KERNEL
static inline int
mbuf_ext_pg_len(struct mbuf_ext_pgs *ext_pgs, int pidx, int pgoff)
{
        KASSERT(pgoff == 0 || pidx == 0,
            ("page %d with non-zero offset %d in %p", pidx, pgoff, ext_pgs));
        if (pidx == ext_pgs->npgs - 1) {
                return (ext_pgs->last_pg_len);
        } else {
                return (PAGE_SIZE - pgoff);
        }
}

#ifdef INVARIANT_SUPPORT
void    mb_ext_pgs_check(struct mbuf_ext_pgs *ext_pgs);
#endif
#ifdef INVARIANTS
#define MBUF_EXT_PGS_ASSERT_SANITY(ext_pgs)     mb_ext_pgs_check((ext_pgs))
#else
#define MBUF_EXT_PGS_ASSERT_SANITY(ext_pgs)
#endif
#endif

/*
 * mbuf flags of global significance and layer crossing.
 * Those of only protocol/layer specific significance are to be mapped
 * to M_PROTO[1-11] 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_NOMAP         0x00000100 /* mbuf data is unmapped */
#define M_NOFREE        0x00000200 /* do not free mbuf, embedded in cluster */
#define M_TSTMP         0x00000400 /* rcv_tstmp field is valid */
#define M_TSTMP_HPREC   0x00000800 /* rcv_tstmp is high-prec, typically
                                      hw-stamped on port (useful for IEEE 1588
                                      and 802.1AS) */
#define M_TSTMP_LRO     0x00001000 /* Time LRO pushed in pkt is valid in (PH_loc) */

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

/*
 * Flags preserved when copying m_pkthdr.
 */
#define M_COPYFLAGS \
    (M_PKTHDR|M_EOR|M_RDONLY|M_BCAST|M_MCAST|M_PROMISC|M_VLANTAG|M_TSTMP| \
     M_TSTMP_HPREC|M_TSTMP_LRO|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\11M_NOMAP\12M_NOFREE\13M_TSTMP\14M_TSTMP_HPREC\15M_TSTMP_LRO"
#define M_FLAG_PROTOBITS \
    "\16M_PROTO1\17M_PROTO2\20M_PROTO3\21M_PROTO4" \
    "\22M_PROTO5\23M_PROTO6\24M_PROTO7\25M_PROTO8\26M_PROTO9" \
    "\27M_PROTO10\28M_PROTO11"
#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.
 *
 * The meaning of the IPV6_EX suffix:
 * "o  Home address from the home address option in the IPv6 destination
 *     options header.  If the extension header is not present, use the Source
 *     IPv6 Address.
 *  o  IPv6 address that is contained in the Routing-Header-Type-2 from the
 *     associated extension header.  If the extension header is not present,
 *     use the Destination IPv6 Address."
 * Quoted from:
 * https://docs.microsoft.com/en-us/windows-hardware/drivers/network/rss-hashing-types#ndishashipv6ex
 */
#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 */
#define M_HASHTYPE_RSS_UDP_IPV4         M_HASHTYPE_HASH(7) /* IPv4 UDP 4-tuple*/
#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)

/*
 * 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 */
#define EXT_RXRING      8       /* data in NIC receive ring */
#define EXT_PGS         9       /* array of unmapped pages */

#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        /* These flags are vendor */
#define EXT_FLAG_VENDOR2        0x020000        /* or submodule specific, */
#define EXT_FLAG_VENDOR3        0x040000        /* not used by mbuf code. */
#define EXT_FLAG_VENDOR4        0x080000        /* Set/read by submodule. */

#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"

#define MBUF_EXT_PGS_ASSERT(m)                                          \
        KASSERT((((m)->m_flags & M_EXT) != 0) &&                        \
            ((m)->m_ext.ext_type == EXT_PGS),                           \
            ("%s: m %p !M_EXT or !EXT_PGS", __func__, m))

/*
 * 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 */

#define CSUM_SND_TAG            0x80000000      /* Packet header has send tag */

/*
 * 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\40CSUM_SND_TAG"

/* 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_EXTCONTROL   15      /* control message with externalized contents */
#define MT_OOBDATA      16      /* expedited data  */

#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"
#define MBUF_EXTPGS_MEM_NAME    "mbuf_extpgs"

#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;
extern uma_zone_t       zone_extpgs;

void             mb_dupcl(struct mbuf *, struct mbuf *);
void             mb_free_ext(struct mbuf *);
void             mb_free_mext_pgs(struct mbuf *);
struct mbuf     *mb_alloc_ext_pgs(int, m_ext_free_t);
int              mb_unmapped_compress(struct mbuf *m);
struct mbuf     *mb_unmapped_to_ext(struct mbuf *m);
void             mb_free_notready(struct mbuf *m, int count);
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));
void             m_dispose_extcontrolm(struct mbuf *m);
struct mbuf     *m_dup(const struct mbuf *, int);
int              m_dup_pkthdr(struct mbuf *, const struct mbuf *, int);
void             m_extadd(struct mbuf *, char *, u_int, m_ext_free_t,
                    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 *, const struct mbuf *, int);
int              m_unmappedtouio(const struct mbuf *, int, struct uio *, 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);
void             m_snd_tag_init(struct m_snd_tag *, struct ifnet *);
void             m_snd_tag_destroy(struct m_snd_tag *);

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, char *buf, u_int size, u_int *ref_cnt,
    m_ext_free_t freef, 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), (char *)(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_NOMAP)) == 0 &&  \
                         (!(((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_NOMAP) ? NULL :                              \
         ((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))

/* Return the rcvif of a packet header. */
static __inline struct ifnet *
m_rcvif(struct mbuf *m)
{

        M_ASSERTPKTHDR(m);
        if (m->m_pkthdr.csum_flags & CSUM_SND_TAG)
                return (NULL);
        return (m->m_pkthdr.rcvif);
}

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

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 */
extern bool             mb_use_ext_pgs; /* Use ext_pgs for sendfile */

/*-
 * 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 m_snd_tag *
m_snd_tag_ref(struct m_snd_tag *mst)
{

        refcount_acquire(&mst->refcount);
        return (mst);
}

static inline void
m_snd_tag_rele(struct m_snd_tag *mst)
{

        if (refcount_release(&mst->refcount))
                m_snd_tag_destroy(mst);
}

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_PKTHDR && m->m_pkthdr.csum_flags & CSUM_SND_TAG)
                m_snd_tag_rele(m->m_pkthdr.snd_tag);
        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_maxlen > 0 && 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++;
}

/*
 * Note: this doesn't enforce the maximum list size for dst.
 */
static inline void
mbufq_concat(struct mbufq *mq_dst, struct mbufq *mq_src)
{

        mq_dst->mq_len += mq_src->mq_len;
        STAILQ_CONCAT(&mq_dst->mq_head, &mq_src->mq_head);
        mq_src->mq_len = 0;
}

#ifdef _SYS_TIMESPEC_H_
static inline void
mbuf_tstmp2timespec(struct mbuf *m, struct timespec *ts)
{

        KASSERT((m->m_flags & M_PKTHDR) != 0, ("mbuf %p no M_PKTHDR", m));
        KASSERT((m->m_flags & (M_TSTMP|M_TSTMP_LRO)) != 0, ("mbuf %p no M_TSTMP or M_TSTMP_LRO", m));
        ts->tv_sec = m->m_pkthdr.rcv_tstmp / 1000000000;
        ts->tv_nsec = m->m_pkthdr.rcv_tstmp % 1000000000;
}
#endif

#ifdef DEBUGNET
/* Invoked from the debugnet client code. */
void    debugnet_mbuf_drain(void);
void    debugnet_mbuf_start(void);
void    debugnet_mbuf_finish(void);
void    debugnet_mbuf_reinit(int nmbuf, int nclust, int clsize);
#endif

static inline bool
mbuf_has_tls_session(struct mbuf *m)
{

        if (m->m_flags & M_NOMAP) {
                MBUF_EXT_PGS_ASSERT(m);
                if (m->m_ext_pgs.tls != NULL) {
                        return (true);
                }
        }
        return (false);
}

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