text: /*-
   * Copyright (c) 1996 - 2001 Brian Somers <brian@Awfulhak.org>
   *          based on work by Toshiharu OHNO <tony-o@iij.ad.jp>
   *                           Internet Initiative Japan, Inc (IIJ)
   * 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.
   *
   * THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
   *
   * $FreeBSD: src/usr.sbin/ppp/mbuf.h,v 1.24.2.3 2002/09/01 02:12:28 brian Exp $
   */
  
  struct mbuf {
    size_t m_size;		/* size allocated (excluding header) */
    u_short m_offset;		/* offset from header end to start position */
    size_t m_len;			/* available byte count in buffer */
    short m_type;			/* MB_* below */
    struct mbuf *m_next;		/* link to next mbuf */
    struct mbuf *m_nextpkt;	/* link to next packet */
    /* buffer space is malloc()d directly after the header */
  };
  
  struct mqueue {
    struct mbuf *top;
    struct mbuf *last;
    size_t len;
  };
  
  #define MBUF_CTOP(bp) \
  	((bp) ? (u_char *)((bp)+1) + (bp)->m_offset : (u_char *)bp)
  
  #define CONST_MBUF_CTOP(bp) \
  	((bp) ? (const u_char *)((bp)+1) + (bp)->m_offset : (const u_char *)bp)
  
  #define MB_IPIN		0
  #define MB_IPOUT	1
  #define MB_IPV6IN	2
  #define MB_IPV6OUT	3
  #define MB_NATIN	4
  #define MB_NATOUT	5
  #define MB_MPIN		6
  #define MB_MPOUT	7
  #define MB_VJIN		8
  #define MB_VJOUT	9
  #define MB_ICOMPDIN	10
  #define MB_ICOMPDOUT	11
  #define MB_COMPDIN	12
  #define MB_COMPDOUT	13
  #define MB_LQRIN	14
  #define MB_LQROUT	15
  #define MB_ECHOIN	16
  #define MB_ECHOOUT	17
  #define MB_PROTOIN	18
  #define MB_PROTOOUT	19
  #define MB_ACFIN	20
  #define MB_ACFOUT	21
  #define MB_SYNCIN	22
  #define MB_SYNCOUT	23
  #define MB_HDLCIN	24
  #define MB_HDLCOUT	25
  #define MB_ASYNCIN	26
  #define MB_ASYNCOUT	27
  #define MB_CBCPIN	28
  #define MB_CBCPOUT	29
  #define MB_CHAPIN	30
  #define MB_CHAPOUT	31
  #define MB_PAPIN	32
  #define MB_PAPOUT	33
  #define MB_CCPIN	34
  #define MB_CCPOUT	35
  #define MB_IPCPIN	36
  #define MB_IPCPOUT	37
  #define MB_IPV6CPIN	38
  #define MB_IPV6CPOUT	39
  #define MB_LCPIN	40
  #define MB_LCPOUT	41
  #define MB_UNKNOWN	42
  #define MB_MAX		MB_UNKNOWN
  
  #define M_MAXLEN	(4352 - sizeof(struct mbuf))	/* > HDLCSIZE */
  
  struct cmdargs;
  
  extern size_t m_length(struct mbuf *);
  extern struct mbuf *m_get(size_t, int);
  extern struct mbuf *m_free(struct mbuf *);
  extern void m_freem(struct mbuf *);
  extern void mbuf_Write(struct mbuf *, const void *, size_t);
  extern struct mbuf *mbuf_Read(struct mbuf *, void *, size_t);
  extern size_t mbuf_View(struct mbuf *, void *, size_t);
  extern struct mbuf *m_prepend(struct mbuf *, const void *, size_t, u_short);
  extern struct mbuf *m_adj(struct mbuf *, ssize_t);
  extern struct mbuf *m_pullup(struct mbuf *);
  extern void m_settype(struct mbuf *, int);
  extern struct mbuf *m_append(struct mbuf *, const void *, size_t);
  
  extern int mbuf_Show(struct cmdargs const *);
  
  extern void m_enqueue(struct mqueue *, struct mbuf *);
  extern struct mbuf *m_dequeue(struct mqueue *);
  