qemu/slirp/mbuf.h

   1 /*
   2  * Copyright (c) 1982, 1986, 1988, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. All advertising materials mentioning features or use of this software
  14  *    must display the following acknowledgement:
  15  *      This product includes software developed by the University of
  16  *      California, Berkeley and its contributors.
  17  * 4. Neither the name of the University nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  *
  33  *      @(#)mbuf.h      8.3 (Berkeley) 1/21/94
  34  * mbuf.h,v 1.9 1994/11/14 13:54:20 bde Exp
  35  */
  36
  37 #ifndef _MBUF_H_
  38 #define _MBUF_H_
  39
  40 #define m_freem m_free
  41
  42
  43 #define MINCSIZE 4096   /* Amount to increase mbuf if too small */
  44
  45 /*
  46  * Macros for type conversion
  47  * mtod(m,t) -  convert mbuf pointer to data pointer of correct type
  48  * dtom(x) -    convert data pointer within mbuf to mbuf pointer (XXX)
  49  */
  50 #define mtod(m,t)       ((t)(m)->m_data)
  51 /* #define      dtom(x)         ((struct mbuf *)((int)(x) & ~(M_SIZE-1))) */
  52
  53 /* XXX About mbufs for slirp:
  54  * Only one mbuf is ever used in a chain, for each "cell" of data.
  55  * m_nextpkt points to the next packet, if fragmented.
  56  * If the data is too large, the M_EXT is used, and a larger block
  57  * is alloced.  Therefore, m_free[m] must check for M_EXT and if set
  58  * free the m_ext.  This is inefficient memory-wise, but who cares.
  59  */
  60
  61 /* XXX should union some of these! */
  62 /* header at beginning of each mbuf: */
  63 struct m_hdr {
  64         struct  mbuf *mh_next;          /* Linked list of mbufs */
  65         struct  mbuf *mh_prev;
  66         struct  mbuf *mh_nextpkt;       /* Next packet in queue/record */
  67         struct  mbuf *mh_prevpkt; /* Flags aren't used in the output queue */
  68         int     mh_flags;         /* Misc flags */
  69
  70         int     mh_size;                /* Size of data */
  71         struct  socket *mh_so;
  72
  73         caddr_t mh_data;                /* Location of data */
  74         int     mh_len;                 /* Amount of data in this mbuf */
  75 };
  76
  77 /*
  78  * How much room is in the mbuf, from m_data to the end of the mbuf
  79  */
  80 #define M_ROOM(m) ((m->m_flags & M_EXT)? \
  81                         (((m)->m_ext + (m)->m_size) - (m)->m_data) \
  82                    : \
  83                         (((m)->m_dat + (m)->m_size) - (m)->m_data))
  84
  85 /*
  86  * How much free room there is
  87  */
  88 #define M_FREEROOM(m) (M_ROOM(m) - (m)->m_len)
  89 #define M_TRAILINGSPACE M_FREEROOM
  90
  91 struct mbuf {
  92         struct  m_hdr m_hdr;
  93         union M_dat {
  94                 char    m_dat_[1]; /* ANSI don't like 0 sized arrays */
  95                 char    *m_ext_;
  96         } M_dat;
  97 };
  98
  99 #define m_next          m_hdr.mh_next
 100 #define m_prev          m_hdr.mh_prev
 101 #define m_nextpkt       m_hdr.mh_nextpkt
 102 #define m_prevpkt       m_hdr.mh_prevpkt
 103 #define m_flags         m_hdr.mh_flags
 104 #define m_len           m_hdr.mh_len
 105 #define m_data          m_hdr.mh_data
 106 #define m_size          m_hdr.mh_size
 107 #define m_dat           M_dat.m_dat_
 108 #define m_ext           M_dat.m_ext_
 109 #define m_so            m_hdr.mh_so
 110
 111 #define ifq_prev m_prev
 112 #define ifq_next m_next
 113 #define ifs_prev m_prevpkt
 114 #define ifs_next m_nextpkt
 115 #define ifq_so m_so
 116
 117 #define M_EXT                   0x01    /* m_ext points to more (malloced) data */
 118 #define M_FREELIST              0x02    /* mbuf is on free list */
 119 #define M_USEDLIST              0x04    /* XXX mbuf is on used list (for dtom()) */
 120 #define M_DOFREE                0x08    /* when m_free is called on the mbuf, free()
 121                                          * it rather than putting it on the free list */
 122
 123 /*
 124  * Mbuf statistics. XXX
 125  */
 126
 127 struct mbstat {
 128         int mbs_alloced;                /* Number of mbufs allocated */
 129
 130 };
 131
 132 extern struct   mbstat mbstat;
 133 extern int mbuf_alloced;
 134 extern struct mbuf m_freelist, m_usedlist;
 135 extern int mbuf_max;
 136
 137 void m_init _P((void));
 138 struct mbuf * m_get _P((void));
 139 void m_free _P((struct mbuf *));
 140 void m_cat _P((register struct mbuf *, register struct mbuf *));
 141 void m_inc _P((struct mbuf *, int));
 142 void m_adj _P((struct mbuf *, int));
 143 int m_copy _P((struct mbuf *, struct mbuf *, int, int));
 144 struct mbuf * dtom _P((void *));
 145
 146 #endif