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