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/*

 * 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        8.3 (Berkeley) 1/21/94

 * mbuf.h,v 1.9 1994/11/14 13:54:20 bde Exp

 */

#ifndef _MBUF_H_

#define _MBUF_H_

#define MINCSIZE 4096        /* Amount to increase mbuf if too small */

/*

 * Macros for type conversion

 * mtod(m,t) -        convert mbuf pointer to data pointer of correct type

 */

#define mtod(m,t)        ((t)(m)->m_data)

/* XXX About mbufs for slirp:

 * Only one mbuf is ever used in a chain, for each "cell" of data.

 * m_nextpkt points to the next packet, if fragmented.

 * If the data is too large, the M_EXT is used, and a larger block

 * is alloced.  Therefore, m_free[m] must check for M_EXT and if set

 * free the m_ext.  This is inefficient memory-wise, but who cares.

 */

/* XXX should union some of these! */

/* header at beginning of each mbuf: */

struct m_hdr {

        struct        mbuf *mh_next;                /* Linked list of mbufs */

        struct        mbuf *mh_prev;

        struct        mbuf *mh_nextpkt;        /* Next packet in queue/record */

        struct        mbuf *mh_prevpkt; /* Flags aren't used in the output queue */

        int        mh_flags;          /* Misc flags */

        int        mh_size;                /* Size of data */

        struct        socket *mh_so;

        caddr_t        mh_data;                /* Location of data */

        int        mh_len;                        /* Amount of data in this mbuf */

};

/*

 * How much room is in the mbuf, from m_data to the end of the mbuf

 */

#define M_ROOM(m) ((m->m_flags & M_EXT)? \

                        (((m)->m_ext + (m)->m_size) - (m)->m_data) \

                   : \

                        (((m)->m_dat + (m)->m_size) - (m)->m_data))

/*

 * How much free room there is

 */

#define M_FREEROOM(m) (M_ROOM(m) - (m)->m_len)

#define M_TRAILINGSPACE M_FREEROOM

struct mbuf {

        struct        m_hdr m_hdr;

        Slirp *slirp;

        union M_dat {

                char        m_dat_[1]; /* ANSI don't like 0 sized arrays */

                char        *m_ext_;

        } M_dat;

};

#define m_next                m_hdr.mh_next

#define m_prev                m_hdr.mh_prev

#define m_nextpkt        m_hdr.mh_nextpkt

#define m_prevpkt        m_hdr.mh_prevpkt

#define m_flags                m_hdr.mh_flags

#define        m_len                m_hdr.mh_len

#define        m_data                m_hdr.mh_data

#define m_size                m_hdr.mh_size

#define m_dat                M_dat.m_dat_

#define m_ext                M_dat.m_ext_

#define m_so                m_hdr.mh_so

#define ifq_prev m_prev

#define ifq_next m_next

#define ifs_prev m_prevpkt

#define ifs_next m_nextpkt

#define ifq_so m_so

#define M_EXT                        0x01        /* m_ext points to more (malloced) data */

#define M_FREELIST                0x02        /* mbuf is on free list */

#define M_USEDLIST                0x04        /* XXX mbuf is on used list (for dtom()) */

#define M_DOFREE                0x08        /* when m_free is called on the mbuf, free()

                                         * it rather than putting it on the free list */

void m_init(Slirp *);

struct mbuf * m_get(Slirp *);

void m_free(struct mbuf *);

void m_cat(register struct mbuf *, register struct mbuf *);

void m_inc(struct mbuf *, int);

void m_adj(struct mbuf *, int);

int m_copy(struct mbuf *, struct mbuf *, int, int);

struct mbuf * dtom(Slirp *, void *);

#endif