user_mbuf.h

Go to the documentation of this file.

/*-
 * 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.
 *
 */

#ifndef _USER_MBUF_H_
#define _USER_MBUF_H_

/* __Userspace__ header file for mbufs */
#include <stdio.h>
#if !defined(SCTP_SIMPLE_ALLOCATOR)
#include "umem.h"
#endif
#include "user_malloc.h"
#include "netinet/sctp_os_userspace.h"

#define USING_MBUF_CONSTRUCTOR 0

/* For Linux */
#ifndef MSIZE
#define MSIZE 256
/* #define MSIZE 1024 */
#endif
#ifndef MCLBYTES
#define MCLBYTES 2048
#endif

struct mbuf * m_gethdr(int how, short type);
struct mbuf * m_get(int how, short type);
struct mbuf * m_free(struct mbuf *m);
void m_clget(struct mbuf *m, int how);


/* mbuf initialization function */
void mbuf_init(void *);

#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 M_HDR_PAD ((sizeof(intptr_t)==4) ? 2 : 6) /* modified for __Userspace__ */

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

/* umem_cache_t is defined in user_include/umem.h as
 * typedef struct umem_cache umem_cache_t;
 * Note:umem_zone_t is a pointer.
 */
#if defined(SCTP_SIMPLE_ALLOCATOR)
typedef size_t sctp_zone_t;
#else
typedef umem_cache_t *sctp_zone_t;
#endif

extern sctp_zone_t zone_mbuf;
extern sctp_zone_t zone_clust;
extern sctp_zone_t zone_ext_refcnt;

/*-
 * Macros for type conversion:
 * mtod(m, t)   -- Convert mbuf pointer to data pointer of correct type.
 * dtom(x)  -- Convert data pointer within mbuf to mbuf pointer (XXX).
 */
#define mtod(m, t)  ((t)((m)->m_data))
#define dtom(x)     ((struct mbuf *)((intptr_t)(x) & ~(MSIZE-1)))

struct mb_args {
    int flags;  /* Flags for mbuf being allocated */
    short   type;   /* Type of mbuf being allocated */
};

struct clust_args {
    struct mbuf * parent_mbuf;
};

struct mbuf *    m_split(struct mbuf *, int, int);
void             m_cat(struct mbuf *m, struct mbuf *n);
void         m_adj(struct mbuf *, int);
void  mb_free_ext(struct mbuf *);
void  m_freem(struct mbuf *);
struct m_tag    *m_tag_alloc(u_int32_t, int, int, int);
struct mbuf *m_copym(struct mbuf *, int, int, int);
void         m_copyback(struct mbuf *, int, int, caddr_t);
struct mbuf *m_pullup(struct mbuf *, int);
struct mbuf *m_pulldown(struct mbuf *, int off, int len, int *offp);
int      m_dup_pkthdr(struct mbuf *, struct mbuf *, int);
struct m_tag    *m_tag_copy(struct m_tag *, int);
int      m_tag_copy_chain(struct mbuf *, struct mbuf *, int);
struct mbuf *m_prepend(struct mbuf *, int, int);
void         m_copydata(const struct mbuf *, int, int, caddr_t);

#define MBUF_MEM_NAME "mbuf"
#define MBUF_CLUSTER_MEM_NAME "mbuf_cluster"
#define MBUF_EXTREFCNT_MEM_NAME "mbuf_ext_refcnt"

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

/*
 * General mbuf allocator statistics structure.
 * __Userspace__ mbstat may be useful for gathering statistics.
 * In the kernel many of these statistics are no longer used as
 * they track allocator statistics through kernel UMA's built in statistics mechanism.
 */
struct mbstat {
    u_long  m_mbufs;    /* XXX */
    u_long  m_mclusts;  /* XXX */

    u_long  m_drain;    /* times drained protocols for space */
    u_long  m_mcfail;   /* XXX: times m_copym failed */
    u_long  m_mpfail;   /* XXX: times m_pullup failed */
    u_long  m_msize;    /* length of an mbuf */
    u_long  m_mclbytes; /* length of an mbuf cluster */
    u_long  m_minclsize;    /* min length of data to allocate a cluster */
    u_long  m_mlen;     /* length of data in an mbuf */
    u_long  m_mhlen;    /* length of data in a header mbuf */

    /* Number of mbtypes (gives # elems in mbtypes[] array: */
    short   m_numtypes;

    /* XXX: Sendfile stats should eventually move to their own struct */
    u_long  sf_iocnt;   /* times sendfile had to do disk I/O */
    u_long  sf_allocfail;   /* times sfbuf allocation failed */
    u_long  sf_allocwait;   /* times sfbuf allocation had to wait */
};


/*
 * 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.
 */
#define MLEN        ((int)(MSIZE - sizeof(struct m_hdr)))   /* normal data len */
#define MHLEN       ((int)(MLEN - sizeof(struct pkthdr)))   /* data len w/pkthdr */
#define MINCLSIZE   ((int)(MHLEN + 1))  /* smallest amount to put in cluster */
#define M_MAXCOMPRESS   (MHLEN / 2) /* max amount to copy for compression */


/*
 * Header present at the beginning of every mbuf.
 */
struct m_hdr {
    struct mbuf *mh_next;   /* next buffer in chain */
    struct mbuf *mh_nextpkt;    /* next chain in queue/record */
    caddr_t      mh_data;   /* location of data */
    int      mh_len;    /* amount of data in this mbuf */
    int      mh_flags;  /* flags; see below */
    short        mh_type;   /* type of data in this mbuf */
    uint8_t          pad[M_HDR_PAD];/* word align                  */
};

/*
 * 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.
 */
struct pkthdr {
    struct ifnet    *rcvif;     /* rcv interface */
    /* variables for ip and tcp reassembly */
    void        *header;    /* pointer to packet header */
    int      len;       /* total packet length */
    /* variables for hardware checksum */
    int      csum_flags;    /* flags regarding checksum */
    int      csum_data; /* data field used by csum routines */
    u_int16_t    tso_segsz; /* TSO segment size */
    u_int16_t    ether_vtag;    /* Ethernet 802.1p+q vlan tag */
    SLIST_HEAD(packet_tags, m_tag) tags; /* list of packet tags */
};

/*
 * Description of external storage mapped into mbuf; valid only if M_EXT is
 * set.
 */
struct m_ext {
    caddr_t      ext_buf;   /* start of buffer */
    void        (*ext_free) /* free routine if not the usual */
                (void *, void *);
    void        *ext_args;  /* optional argument pointer */
    u_int        ext_size;  /* size of buffer, for ext_free */
    volatile u_int  *ref_cnt;   /* pointer to ref count info */
    int      ext_type;  /* type of external storage */
};


/*
 * The core of the mbuf object along with some shortcut defined for practical
 * purposes.
 */
struct mbuf {
    struct m_hdr    m_hdr;
    union {
        struct {
            struct pkthdr   MH_pkthdr;  /* M_PKTHDR set */
            union {
                struct m_ext    MH_ext; /* M_EXT set */
                char        MH_databuf[MHLEN];
            } MH_dat;
        } MH;
        char    M_databuf[MLEN];        /* !M_PKTHDR, !M_EXT */
    } M_dat;
};

#define m_next      m_hdr.mh_next
#define m_len       m_hdr.mh_len
#define m_data      m_hdr.mh_data
#define m_type      m_hdr.mh_type
#define m_flags     m_hdr.mh_flags
#define m_nextpkt   m_hdr.mh_nextpkt
#define m_act       m_nextpkt
#define m_pkthdr    M_dat.MH.MH_pkthdr
#define m_ext       M_dat.MH.MH_dat.MH_ext
#define m_pktdat    M_dat.MH.MH_dat.MH_databuf
#define m_dat       M_dat.M_databuf


/*
 * mbuf flags.
 */
#define M_EXT       0x0001  /* has associated external storage */
#define M_PKTHDR    0x0002  /* start of record */
#define M_EOR       0x0004  /* end of record */
#define M_RDONLY    0x0008  /* associated data is marked read-only */
#define M_PROTO1    0x0010  /* protocol-specific */
#define M_PROTO2    0x0020  /* protocol-specific */
#define M_PROTO3    0x0040  /* protocol-specific */
#define M_PROTO4    0x0080  /* protocol-specific */
#define M_PROTO5    0x0100  /* protocol-specific */
#define M_FREELIST  0x8000  /* mbuf is on the free list */


/*
 * Flags copied when copying m_pkthdr.
 */
#define M_COPYFLAGS (M_PKTHDR|M_EOR|M_RDONLY|M_PROTO1|M_PROTO1|M_PROTO2|\
                M_PROTO3|M_PROTO4|M_PROTO5|\
                M_BCAST|M_MCAST|M_FRAG|M_FIRSTFRAG|M_LASTFRAG|\
                M_VLANTAG|M_PROMISC)


/*
 * mbuf pkthdr flags (also stored in m_flags).
 */
#define M_BCAST     0x0200  /* send/received as link-level broadcast */
#define M_MCAST     0x0400  /* send/received as link-level multicast */
#define M_FRAG      0x0800  /* packet is a fragment of a larger packet */
#define M_FIRSTFRAG 0x1000  /* packet is first fragment */
#define M_LASTFRAG  0x2000  /* packet is last fragment */
#define M_VLANTAG   0x10000 /* ether_vtag is valid */
#define M_PROMISC   0x20000 /* packet was not for us */
#define M_NOFREE    0x40000 /* do not free mbuf - it is embedded in the cluster */


/*
 * External buffer types: identify ext_buf type.
 */
#define EXT_CLUSTER 1   /* mbuf cluster */
#define EXT_SFBUF   2   /* sendfile(2)'s sf_bufs */
#define EXT_JUMBOP  3   /* jumbo cluster 4096 bytes */
#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_NET_DRV 100 /* custom ext_buf provided by net driver(s) */
#define EXT_MOD_TYPE    200 /* custom module's ext_buf type */
#define EXT_DISPOSABLE  300 /* can throw this buffer away w/page flipping */
#define EXT_EXTREF  400 /* has externally maintained ref_cnt ptr */


/*
 * mbuf types.
 */
#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_SONAME   8   /* socket name */
#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 */

/*
 * __Userspace__ flags like M_NOWAIT are defined in malloc.h
 * Flags like these are used in functions like uma_zalloc()
 * but don't have an equivalent in userland umem
 * Flags specifying how an allocation should be made.
 *
 * The flag to use is as follows:
 * - M_DONTWAIT or M_NOWAIT from an interrupt handler to not block allocation.
 * - M_WAIT or M_WAITOK or M_TRYWAIT from wherever it is safe to block.
 *
 * M_DONTWAIT/M_NOWAIT means that we will not block the thread explicitly and
 * if we cannot allocate immediately we may return NULL, whereas
 * M_WAIT/M_WAITOK/M_TRYWAIT means that if we cannot allocate resources we
 * will block until they are available, and thus never return NULL.
 *
 * XXX Eventually just phase this out to use M_WAITOK/M_NOWAIT.
 */
#define MBTOM(how)  (how)

void         m_tag_delete(struct mbuf *, struct m_tag *);
void         m_tag_delete_chain(struct mbuf *, struct m_tag *);
void         m_move_pkthdr(struct mbuf *, struct mbuf *);
void         m_tag_free_default(struct m_tag *);

extern int max_linkhdr;    /* Largest link-level header */
extern int max_protohdr; /* Size of largest protocol layer header. See user_mbuf.c */

extern struct mbstat    mbstat;     /* General mbuf stats/infos */


/*
 * 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)->m_ext.ref_cnt) == 1)) )        \


/*
 * 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.
 */
#define M_LEADINGSPACE(m)                       \
    ((m)->m_flags & M_EXT ?                     \
        (M_WRITABLE(m) ? (m)->m_data - (m)->m_ext.ext_buf : 0): \
        (m)->m_flags & M_PKTHDR ? (m)->m_data - (m)->m_pktdat : \
        (m)->m_data - (m)->m_dat)

/*
 * 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.
 */
#define M_TRAILINGSPACE(m)                      \
    ((m)->m_flags & M_EXT ?                     \
        (M_WRITABLE(m) ? (m)->m_ext.ext_buf + (m)->m_ext.ext_size   \
        - ((m)->m_data + (m)->m_len) : 0) :         \
        &(m)->m_dat[MLEN] - ((m)->m_data + (m)->m_len))



/*
 * 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);                     \
                                    \
    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)

/*
 * Set the m_data pointer of a newly-allocated mbuf (m_get/MGET) to place an
 * object of the specified size at the end of the mbuf, longword aligned.
 */
#define M_ALIGN(m, len) do {                        \
        KASSERT(!((m)->m_flags & (M_PKTHDR|M_EXT)),                     \
                ("%s: M_ALIGN not normal mbuf", __func__));             \
        KASSERT((m)->m_data == (m)->m_dat,                              \
                ("%s: M_ALIGN not a virgin mbuf", __func__));           \
    (m)->m_data += (MLEN - (len)) & ~(sizeof(long) - 1);        \
} while (0)

/*
 * As above, for mbufs allocated with m_gethdr/MGETHDR or initialized by
 * M_DUP/MOVE_PKTHDR.
 */
#define MH_ALIGN(m, len) do {                       \
        KASSERT((m)->m_flags & M_PKTHDR && !((m)->m_flags & M_EXT),     \
                ("%s: MH_ALIGN not PKTHDR mbuf", __func__));            \
        KASSERT((m)->m_data == (m)->m_pktdat,                           \
                ("%s: MH_ALIGN not a virgin mbuf", __func__));          \
    (m)->m_data += (MHLEN - (len)) & ~(sizeof(long) - 1);       \
} while (0)

#endif