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/*
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 * Copyright (c) 1982, 1986, 1988, 1993
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 *        The Regents of the University of California.  All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 * 1. Redistributions of source code must retain the above copyright
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 *    notice, this list of conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    notice, this list of conditions and the following disclaimer in the
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 *    documentation and/or other materials provided with the distribution.
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 * 3. All advertising materials mentioning features or use of this software
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 *    must display the following acknowledgement:
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 *        This product includes software developed by the University of
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 *        California, Berkeley and its contributors.
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 * 4. Neither the name of the University nor the names of its contributors
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 *    may be used to endorse or promote products derived from this software
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 *    without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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 * SUCH DAMAGE.
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 *
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 *        @(#)mbuf.h        8.3 (Berkeley) 1/21/94
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 * mbuf.h,v 1.9 1994/11/14 13:54:20 bde Exp
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 */
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#ifndef _MBUF_H_
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#define _MBUF_H_
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#define m_freem m_free
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#define MINCSIZE 4096        /* Amount to increase mbuf if too small */
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/*
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 * Macros for type conversion
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 * mtod(m,t) -        convert mbuf pointer to data pointer of correct type
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 * dtom(x) -        convert data pointer within mbuf to mbuf pointer (XXX)
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 */
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#define mtod(m,t)        ((t)(m)->m_data)
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/* #define        dtom(x)                ((struct mbuf *)((int)(x) & ~(M_SIZE-1))) */
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/* XXX About mbufs for slirp:
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 * Only one mbuf is ever used in a chain, for each "cell" of data.
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 * m_nextpkt points to the next packet, if fragmented.
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 * If the data is too large, the M_EXT is used, and a larger block
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 * is alloced.  Therefore, m_free[m] must check for M_EXT and if set
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 * free the m_ext.  This is inefficient memory-wise, but who cares.
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 */
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/* XXX should union some of these! */
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/* header at beginning of each mbuf: */
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struct m_hdr {
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        struct        mbuf *mh_next;                /* Linked list of mbufs */
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        struct        mbuf *mh_prev;
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        struct        mbuf *mh_nextpkt;        /* Next packet in queue/record */
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        struct        mbuf *mh_prevpkt; /* Flags aren't used in the output queue */
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        int        mh_flags;          /* Misc flags */
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        int        mh_size;                /* Size of data */
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        struct        socket *mh_so;
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        caddr_t        mh_data;                /* Location of data */
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        int        mh_len;                        /* Amount of data in this mbuf */
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};
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/*
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 * How much room is in the mbuf, from m_data to the end of the mbuf
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 */
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#define M_ROOM(m) ((m->m_flags & M_EXT)? \
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                        (((m)->m_ext + (m)->m_size) - (m)->m_data) \
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                   : \
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                        (((m)->m_dat + (m)->m_size) - (m)->m_data))
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/*
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 * How much free room there is
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 */
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#define M_FREEROOM(m) (M_ROOM(m) - (m)->m_len)
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#define M_TRAILINGSPACE M_FREEROOM
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struct mbuf {
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        struct        m_hdr m_hdr;
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        union M_dat {
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                char        m_dat_[1]; /* ANSI don't like 0 sized arrays */
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                char        *m_ext_;
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        } M_dat;
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};
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#define m_next                m_hdr.mh_next
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#define m_prev                m_hdr.mh_prev
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#define m_nextpkt        m_hdr.mh_nextpkt
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#define m_prevpkt        m_hdr.mh_prevpkt
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#define m_flags                m_hdr.mh_flags
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#define        m_len                m_hdr.mh_len
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#define        m_data                m_hdr.mh_data
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#define m_size                m_hdr.mh_size
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#define m_dat                M_dat.m_dat_
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#define m_ext                M_dat.m_ext_
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#define m_so                m_hdr.mh_so
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#define ifq_prev m_prev
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#define ifq_next m_next
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#define ifs_prev m_prevpkt
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#define ifs_next m_nextpkt
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#define ifq_so m_so
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#define M_EXT                        0x01        /* m_ext points to more (malloced) data */
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#define M_FREELIST                0x02        /* mbuf is on free list */
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#define M_USEDLIST                0x04        /* XXX mbuf is on used list (for dtom()) */
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#define M_DOFREE                0x08        /* when m_free is called on the mbuf, free()
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                                         * it rather than putting it on the free list */
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/*
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 * Mbuf statistics. XXX
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 */
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struct mbstat {
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        int mbs_alloced;                /* Number of mbufs allocated */
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};
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extern struct        mbstat mbstat;
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extern int mbuf_alloced;
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extern struct mbuf m_freelist, m_usedlist;
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extern int mbuf_max;
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void m_init _P((void));
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void msize_init _P((void));
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struct mbuf * m_get _P((void));
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void m_free _P((struct mbuf *));
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void m_cat _P((register struct mbuf *, register struct mbuf *));
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void m_inc _P((struct mbuf *, int));
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void m_adj _P((struct mbuf *, int));
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int m_copy _P((struct mbuf *, struct mbuf *, int, int));
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struct mbuf * dtom _P((void *));
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#endif